2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arm Files generic to ARM architecture
136 /cpu CPU specific files
137 /arm720t Files specific to ARM 720 CPUs
138 /arm920t Files specific to ARM 920 CPUs
139 /at91 Files specific to Atmel AT91RM9200 CPU
140 /imx Files specific to Freescale MC9328 i.MX CPUs
141 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
142 /arm926ejs Files specific to ARM 926 CPUs
143 /arm1136 Files specific to ARM 1136 CPUs
144 /ixp Files specific to Intel XScale IXP CPUs
145 /pxa Files specific to Intel XScale PXA CPUs
146 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
147 /lib Architecture specific library files
148 /avr32 Files generic to AVR32 architecture
149 /cpu CPU specific files
150 /lib Architecture specific library files
151 /blackfin Files generic to Analog Devices Blackfin architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /m68k Files generic to m68k architecture
155 /cpu CPU specific files
156 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
157 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
158 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
159 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
160 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
161 /lib Architecture specific library files
162 /microblaze Files generic to microblaze architecture
163 /cpu CPU specific files
164 /lib Architecture specific library files
165 /mips Files generic to MIPS architecture
166 /cpu CPU specific files
167 /mips32 Files specific to MIPS32 CPUs
168 /xburst Files specific to Ingenic XBurst CPUs
169 /lib Architecture specific library files
170 /nds32 Files generic to NDS32 architecture
171 /cpu CPU specific files
172 /n1213 Files specific to Andes Technology N1213 CPUs
173 /lib Architecture specific library files
174 /nios2 Files generic to Altera NIOS2 architecture
175 /cpu CPU specific files
176 /lib Architecture specific library files
177 /openrisc Files generic to OpenRISC architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /powerpc Files generic to PowerPC architecture
181 /cpu CPU specific files
182 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
183 /mpc5xx Files specific to Freescale MPC5xx CPUs
184 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
185 /mpc8xx Files specific to Freescale MPC8xx CPUs
186 /mpc824x Files specific to Freescale MPC824x CPUs
187 /mpc8260 Files specific to Freescale MPC8260 CPUs
188 /mpc85xx Files specific to Freescale MPC85xx CPUs
189 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
190 /lib Architecture specific library files
191 /sh Files generic to SH architecture
192 /cpu CPU specific files
193 /sh2 Files specific to sh2 CPUs
194 /sh3 Files specific to sh3 CPUs
195 /sh4 Files specific to sh4 CPUs
196 /lib Architecture specific library files
197 /sparc Files generic to SPARC architecture
198 /cpu CPU specific files
199 /leon2 Files specific to Gaisler LEON2 SPARC CPU
200 /leon3 Files specific to Gaisler LEON3 SPARC CPU
201 /lib Architecture specific library files
202 /x86 Files generic to x86 architecture
203 /cpu CPU specific files
204 /lib Architecture specific library files
205 /api Machine/arch independent API for external apps
206 /board Board dependent files
207 /common Misc architecture independent functions
208 /disk Code for disk drive partition handling
209 /doc Documentation (don't expect too much)
210 /drivers Commonly used device drivers
211 /dts Contains Makefile for building internal U-Boot fdt.
212 /examples Example code for standalone applications, etc.
213 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
214 /include Header Files
215 /lib Files generic to all architectures
216 /libfdt Library files to support flattened device trees
217 /lzma Library files to support LZMA decompression
218 /lzo Library files to support LZO decompression
220 /post Power On Self Test
221 /spl Secondary Program Loader framework
222 /tools Tools to build S-Record or U-Boot images, etc.
224 Software Configuration:
225 =======================
227 Configuration is usually done using C preprocessor defines; the
228 rationale behind that is to avoid dead code whenever possible.
230 There are two classes of configuration variables:
232 * Configuration _OPTIONS_:
233 These are selectable by the user and have names beginning with
236 * Configuration _SETTINGS_:
237 These depend on the hardware etc. and should not be meddled with if
238 you don't know what you're doing; they have names beginning with
241 Later we will add a configuration tool - probably similar to or even
242 identical to what's used for the Linux kernel. Right now, we have to
243 do the configuration by hand, which means creating some symbolic
244 links and editing some configuration files. We use the TQM8xxL boards
248 Selection of Processor Architecture and Board Type:
249 ---------------------------------------------------
251 For all supported boards there are ready-to-use default
252 configurations available; just type "make <board_name>_config".
254 Example: For a TQM823L module type:
259 For the Cogent platform, you need to specify the CPU type as well;
260 e.g. "make cogent_mpc8xx_config". And also configure the cogent
261 directory according to the instructions in cogent/README.
264 Configuration Options:
265 ----------------------
267 Configuration depends on the combination of board and CPU type; all
268 such information is kept in a configuration file
269 "include/configs/<board_name>.h".
271 Example: For a TQM823L module, all configuration settings are in
272 "include/configs/TQM823L.h".
275 Many of the options are named exactly as the corresponding Linux
276 kernel configuration options. The intention is to make it easier to
277 build a config tool - later.
280 The following options need to be configured:
282 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
284 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
286 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
287 Define exactly one, e.g. CONFIG_ATSTK1002
289 - CPU Module Type: (if CONFIG_COGENT is defined)
290 Define exactly one of
292 --- FIXME --- not tested yet:
293 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
294 CONFIG_CMA287_23, CONFIG_CMA287_50
296 - Motherboard Type: (if CONFIG_COGENT is defined)
297 Define exactly one of
298 CONFIG_CMA101, CONFIG_CMA102
300 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
301 Define one or more of
304 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
305 Define one or more of
306 CONFIG_LCD_HEARTBEAT - update a character position on
307 the LCD display every second with
310 - Board flavour: (if CONFIG_MPC8260ADS is defined)
313 CONFIG_SYS_8260ADS - original MPC8260ADS
314 CONFIG_SYS_8266ADS - MPC8266ADS
315 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
316 CONFIG_SYS_8272ADS - MPC8272ADS
318 - Marvell Family Member
319 CONFIG_SYS_MVFS - define it if you want to enable
320 multiple fs option at one time
321 for marvell soc family
323 - MPC824X Family Member (if CONFIG_MPC824X is defined)
324 Define exactly one of
325 CONFIG_MPC8240, CONFIG_MPC8245
327 - 8xx CPU Options: (if using an MPC8xx CPU)
328 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
329 get_gclk_freq() cannot work
330 e.g. if there is no 32KHz
331 reference PIT/RTC clock
332 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
335 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
336 CONFIG_SYS_8xx_CPUCLK_MIN
337 CONFIG_SYS_8xx_CPUCLK_MAX
338 CONFIG_8xx_CPUCLK_DEFAULT
339 See doc/README.MPC866
341 CONFIG_SYS_MEASURE_CPUCLK
343 Define this to measure the actual CPU clock instead
344 of relying on the correctness of the configured
345 values. Mostly useful for board bringup to make sure
346 the PLL is locked at the intended frequency. Note
347 that this requires a (stable) reference clock (32 kHz
348 RTC clock or CONFIG_SYS_8XX_XIN)
350 CONFIG_SYS_DELAYED_ICACHE
352 Define this option if you want to enable the
353 ICache only when Code runs from RAM.
358 Specifies that the core is a 64-bit PowerPC implementation (implements
359 the "64" category of the Power ISA). This is necessary for ePAPR
360 compliance, among other possible reasons.
362 CONFIG_SYS_FSL_TBCLK_DIV
364 Defines the core time base clock divider ratio compared to the
365 system clock. On most PQ3 devices this is 8, on newer QorIQ
366 devices it can be 16 or 32. The ratio varies from SoC to Soc.
368 CONFIG_SYS_FSL_PCIE_COMPAT
370 Defines the string to utilize when trying to match PCIe device
371 tree nodes for the given platform.
373 CONFIG_SYS_PPC_E500_DEBUG_TLB
375 Enables a temporary TLB entry to be used during boot to work
376 around limitations in e500v1 and e500v2 external debugger
377 support. This reduces the portions of the boot code where
378 breakpoints and single stepping do not work. The value of this
379 symbol should be set to the TLB1 entry to be used for this
382 CONFIG_SYS_FSL_ERRATUM_A004510
384 Enables a workaround for erratum A004510. If set,
385 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
386 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
388 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
389 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
391 Defines one or two SoC revisions (low 8 bits of SVR)
392 for which the A004510 workaround should be applied.
394 The rest of SVR is either not relevant to the decision
395 of whether the erratum is present (e.g. p2040 versus
396 p2041) or is implied by the build target, which controls
397 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
399 See Freescale App Note 4493 for more information about
402 CONFIG_A003399_NOR_WORKAROUND
403 Enables a workaround for IFC erratum A003399. It is only
404 requred during NOR boot.
406 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
408 This is the value to write into CCSR offset 0x18600
409 according to the A004510 workaround.
411 CONFIG_SYS_FSL_DSP_DDR_ADDR
412 This value denotes start offset of DDR memory which is
413 connected exclusively to the DSP cores.
415 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
416 This value denotes start offset of M2 memory
417 which is directly connected to the DSP core.
419 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
420 This value denotes start offset of M3 memory which is directly
421 connected to the DSP core.
423 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
424 This value denotes start offset of DSP CCSR space.
426 CONFIG_SYS_FSL_DDR_EMU
427 Specify emulator support for DDR. Some DDR features such as
428 deskew training are not available.
430 - Generic CPU options:
431 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
433 Defines the endianess of the CPU. Implementation of those
434 values is arch specific.
436 - Intel Monahans options:
437 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
439 Defines the Monahans run mode to oscillator
440 ratio. Valid values are 8, 16, 24, 31. The core
441 frequency is this value multiplied by 13 MHz.
443 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
445 Defines the Monahans turbo mode to oscillator
446 ratio. Valid values are 1 (default if undefined) and
447 2. The core frequency as calculated above is multiplied
451 CONFIG_SYS_INIT_SP_OFFSET
453 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
454 pointer. This is needed for the temporary stack before
457 CONFIG_SYS_MIPS_CACHE_MODE
459 Cache operation mode for the MIPS CPU.
460 See also arch/mips/include/asm/mipsregs.h.
462 CONF_CM_CACHABLE_NO_WA
465 CONF_CM_CACHABLE_NONCOHERENT
469 CONF_CM_CACHABLE_ACCELERATED
471 CONFIG_SYS_XWAY_EBU_BOOTCFG
473 Special option for Lantiq XWAY SoCs for booting from NOR flash.
474 See also arch/mips/cpu/mips32/start.S.
476 CONFIG_XWAY_SWAP_BYTES
478 Enable compilation of tools/xway-swap-bytes needed for Lantiq
479 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
480 be swapped if a flash programmer is used.
483 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
485 Select high exception vectors of the ARM core, e.g., do not
486 clear the V bit of the c1 register of CP15.
488 CONFIG_SYS_THUMB_BUILD
490 Use this flag to build U-Boot using the Thumb instruction
491 set for ARM architectures. Thumb instruction set provides
492 better code density. For ARM architectures that support
493 Thumb2 this flag will result in Thumb2 code generated by
496 CONFIG_ARM_ERRATA_716044
497 CONFIG_ARM_ERRATA_742230
498 CONFIG_ARM_ERRATA_743622
499 CONFIG_ARM_ERRATA_751472
501 If set, the workarounds for these ARM errata are applied early
502 during U-Boot startup. Note that these options force the
503 workarounds to be applied; no CPU-type/version detection
504 exists, unlike the similar options in the Linux kernel. Do not
505 set these options unless they apply!
510 The frequency of the timer returned by get_timer().
511 get_timer() must operate in milliseconds and this CONFIG
512 option must be set to 1000.
514 - Linux Kernel Interface:
517 U-Boot stores all clock information in Hz
518 internally. For binary compatibility with older Linux
519 kernels (which expect the clocks passed in the
520 bd_info data to be in MHz) the environment variable
521 "clocks_in_mhz" can be defined so that U-Boot
522 converts clock data to MHZ before passing it to the
524 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
525 "clocks_in_mhz=1" is automatically included in the
528 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
530 When transferring memsize parameter to linux, some versions
531 expect it to be in bytes, others in MB.
532 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
536 New kernel versions are expecting firmware settings to be
537 passed using flattened device trees (based on open firmware
541 * New libfdt-based support
542 * Adds the "fdt" command
543 * The bootm command automatically updates the fdt
545 OF_CPU - The proper name of the cpus node (only required for
546 MPC512X and MPC5xxx based boards).
547 OF_SOC - The proper name of the soc node (only required for
548 MPC512X and MPC5xxx based boards).
549 OF_TBCLK - The timebase frequency.
550 OF_STDOUT_PATH - The path to the console device
552 boards with QUICC Engines require OF_QE to set UCC MAC
555 CONFIG_OF_BOARD_SETUP
557 Board code has addition modification that it wants to make
558 to the flat device tree before handing it off to the kernel
562 This define fills in the correct boot CPU in the boot
563 param header, the default value is zero if undefined.
567 U-Boot can detect if an IDE device is present or not.
568 If not, and this new config option is activated, U-Boot
569 removes the ATA node from the DTS before booting Linux,
570 so the Linux IDE driver does not probe the device and
571 crash. This is needed for buggy hardware (uc101) where
572 no pull down resistor is connected to the signal IDE5V_DD7.
574 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
576 This setting is mandatory for all boards that have only one
577 machine type and must be used to specify the machine type
578 number as it appears in the ARM machine registry
579 (see http://www.arm.linux.org.uk/developer/machines/).
580 Only boards that have multiple machine types supported
581 in a single configuration file and the machine type is
582 runtime discoverable, do not have to use this setting.
584 - vxWorks boot parameters:
586 bootvx constructs a valid bootline using the following
587 environments variables: bootfile, ipaddr, serverip, hostname.
588 It loads the vxWorks image pointed bootfile.
590 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
591 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
592 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
593 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
595 CONFIG_SYS_VXWORKS_ADD_PARAMS
597 Add it at the end of the bootline. E.g "u=username pw=secret"
599 Note: If a "bootargs" environment is defined, it will overwride
600 the defaults discussed just above.
602 - Cache Configuration:
603 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
604 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
605 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
607 - Cache Configuration for ARM:
608 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
610 CONFIG_SYS_PL310_BASE - Physical base address of PL310
611 controller register space
616 Define this if you want support for Amba PrimeCell PL010 UARTs.
620 Define this if you want support for Amba PrimeCell PL011 UARTs.
624 If you have Amba PrimeCell PL011 UARTs, set this variable to
625 the clock speed of the UARTs.
629 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
630 define this to a list of base addresses for each (supported)
631 port. See e.g. include/configs/versatile.h
633 CONFIG_PL011_SERIAL_RLCR
635 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
636 have separate receive and transmit line control registers. Set
637 this variable to initialize the extra register.
639 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
641 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
642 boot loader that has already initialized the UART. Define this
643 variable to flush the UART at init time.
647 Depending on board, define exactly one serial port
648 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
649 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
650 console by defining CONFIG_8xx_CONS_NONE
652 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
653 port routines must be defined elsewhere
654 (i.e. serial_init(), serial_getc(), ...)
657 Enables console device for a color framebuffer. Needs following
658 defines (cf. smiLynxEM, i8042)
659 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
661 VIDEO_HW_RECTFILL graphic chip supports
664 VIDEO_HW_BITBLT graphic chip supports
665 bit-blit (cf. smiLynxEM)
666 VIDEO_VISIBLE_COLS visible pixel columns
668 VIDEO_VISIBLE_ROWS visible pixel rows
669 VIDEO_PIXEL_SIZE bytes per pixel
670 VIDEO_DATA_FORMAT graphic data format
671 (0-5, cf. cfb_console.c)
672 VIDEO_FB_ADRS framebuffer address
673 VIDEO_KBD_INIT_FCT keyboard int fct
674 (i.e. i8042_kbd_init())
675 VIDEO_TSTC_FCT test char fct
677 VIDEO_GETC_FCT get char fct
679 CONFIG_CONSOLE_CURSOR cursor drawing on/off
680 (requires blink timer
682 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
683 CONFIG_CONSOLE_TIME display time/date info in
685 (requires CONFIG_CMD_DATE)
686 CONFIG_VIDEO_LOGO display Linux logo in
688 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
689 linux_logo.h for logo.
690 Requires CONFIG_VIDEO_LOGO
691 CONFIG_CONSOLE_EXTRA_INFO
692 additional board info beside
695 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
696 a limited number of ANSI escape sequences (cursor control,
697 erase functions and limited graphics rendition control).
699 When CONFIG_CFB_CONSOLE is defined, video console is
700 default i/o. Serial console can be forced with
701 environment 'console=serial'.
703 When CONFIG_SILENT_CONSOLE is defined, all console
704 messages (by U-Boot and Linux!) can be silenced with
705 the "silent" environment variable. See
706 doc/README.silent for more information.
708 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
710 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
714 CONFIG_BAUDRATE - in bps
715 Select one of the baudrates listed in
716 CONFIG_SYS_BAUDRATE_TABLE, see below.
717 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
719 - Console Rx buffer length
720 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
721 the maximum receive buffer length for the SMC.
722 This option is actual only for 82xx and 8xx possible.
723 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
724 must be defined, to setup the maximum idle timeout for
727 - Pre-Console Buffer:
728 Prior to the console being initialised (i.e. serial UART
729 initialised etc) all console output is silently discarded.
730 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
731 buffer any console messages prior to the console being
732 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
733 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
734 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
735 bytes are output before the console is initialised, the
736 earlier bytes are discarded.
738 'Sane' compilers will generate smaller code if
739 CONFIG_PRE_CON_BUF_SZ is a power of 2
741 - Safe printf() functions
742 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
743 the printf() functions. These are defined in
744 include/vsprintf.h and include snprintf(), vsnprintf() and
745 so on. Code size increase is approximately 300-500 bytes.
746 If this option is not given then these functions will
747 silently discard their buffer size argument - this means
748 you are not getting any overflow checking in this case.
750 - Boot Delay: CONFIG_BOOTDELAY - in seconds
751 Delay before automatically booting the default image;
752 set to -1 to disable autoboot.
753 set to -2 to autoboot with no delay and not check for abort
754 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
756 See doc/README.autoboot for these options that
757 work with CONFIG_BOOTDELAY. None are required.
758 CONFIG_BOOT_RETRY_TIME
759 CONFIG_BOOT_RETRY_MIN
760 CONFIG_AUTOBOOT_KEYED
761 CONFIG_AUTOBOOT_PROMPT
762 CONFIG_AUTOBOOT_DELAY_STR
763 CONFIG_AUTOBOOT_STOP_STR
764 CONFIG_AUTOBOOT_DELAY_STR2
765 CONFIG_AUTOBOOT_STOP_STR2
766 CONFIG_ZERO_BOOTDELAY_CHECK
767 CONFIG_RESET_TO_RETRY
771 Only needed when CONFIG_BOOTDELAY is enabled;
772 define a command string that is automatically executed
773 when no character is read on the console interface
774 within "Boot Delay" after reset.
777 This can be used to pass arguments to the bootm
778 command. The value of CONFIG_BOOTARGS goes into the
779 environment value "bootargs".
781 CONFIG_RAMBOOT and CONFIG_NFSBOOT
782 The value of these goes into the environment as
783 "ramboot" and "nfsboot" respectively, and can be used
784 as a convenience, when switching between booting from
788 CONFIG_BOOTCOUNT_LIMIT
789 Implements a mechanism for detecting a repeating reboot
791 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
794 If no softreset save registers are found on the hardware
795 "bootcount" is stored in the environment. To prevent a
796 saveenv on all reboots, the environment variable
797 "upgrade_available" is used. If "upgrade_available" is
798 0, "bootcount" is always 0, if "upgrade_available" is
799 1 "bootcount" is incremented in the environment.
800 So the Userspace Applikation must set the "upgrade_available"
801 and "bootcount" variable to 0, if a boot was successfully.
806 When this option is #defined, the existence of the
807 environment variable "preboot" will be checked
808 immediately before starting the CONFIG_BOOTDELAY
809 countdown and/or running the auto-boot command resp.
810 entering interactive mode.
812 This feature is especially useful when "preboot" is
813 automatically generated or modified. For an example
814 see the LWMON board specific code: here "preboot" is
815 modified when the user holds down a certain
816 combination of keys on the (special) keyboard when
819 - Serial Download Echo Mode:
821 If defined to 1, all characters received during a
822 serial download (using the "loads" command) are
823 echoed back. This might be needed by some terminal
824 emulations (like "cu"), but may as well just take
825 time on others. This setting #define's the initial
826 value of the "loads_echo" environment variable.
828 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
830 Select one of the baudrates listed in
831 CONFIG_SYS_BAUDRATE_TABLE, see below.
834 Monitor commands can be included or excluded
835 from the build by using the #include files
836 <config_cmd_all.h> and #undef'ing unwanted
837 commands, or using <config_cmd_default.h>
838 and augmenting with additional #define's
841 The default command configuration includes all commands
842 except those marked below with a "*".
844 CONFIG_CMD_ASKENV * ask for env variable
845 CONFIG_CMD_BDI bdinfo
846 CONFIG_CMD_BEDBUG * Include BedBug Debugger
847 CONFIG_CMD_BMP * BMP support
848 CONFIG_CMD_BSP * Board specific commands
849 CONFIG_CMD_BOOTD bootd
850 CONFIG_CMD_CACHE * icache, dcache
851 CONFIG_CMD_CONSOLE coninfo
852 CONFIG_CMD_CRC32 * crc32
853 CONFIG_CMD_DATE * support for RTC, date/time...
854 CONFIG_CMD_DHCP * DHCP support
855 CONFIG_CMD_DIAG * Diagnostics
856 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
857 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
858 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
859 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
860 CONFIG_CMD_DTT * Digital Therm and Thermostat
861 CONFIG_CMD_ECHO echo arguments
862 CONFIG_CMD_EDITENV edit env variable
863 CONFIG_CMD_EEPROM * EEPROM read/write support
864 CONFIG_CMD_ELF * bootelf, bootvx
865 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
866 CONFIG_CMD_ENV_FLAGS * display details about env flags
867 CONFIG_CMD_ENV_EXISTS * check existence of env variable
868 CONFIG_CMD_EXPORTENV * export the environment
869 CONFIG_CMD_EXT2 * ext2 command support
870 CONFIG_CMD_EXT4 * ext4 command support
871 CONFIG_CMD_SAVEENV saveenv
872 CONFIG_CMD_FDC * Floppy Disk Support
873 CONFIG_CMD_FAT * FAT command support
874 CONFIG_CMD_FDOS * Dos diskette Support
875 CONFIG_CMD_FLASH flinfo, erase, protect
876 CONFIG_CMD_FPGA FPGA device initialization support
877 CONFIG_CMD_FUSE * Device fuse support
878 CONFIG_CMD_GETTIME * Get time since boot
879 CONFIG_CMD_GO * the 'go' command (exec code)
880 CONFIG_CMD_GREPENV * search environment
881 CONFIG_CMD_HASH * calculate hash / digest
882 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
883 CONFIG_CMD_I2C * I2C serial bus support
884 CONFIG_CMD_IDE * IDE harddisk support
885 CONFIG_CMD_IMI iminfo
886 CONFIG_CMD_IMLS List all images found in NOR flash
887 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
888 CONFIG_CMD_IMMAP * IMMR dump support
889 CONFIG_CMD_IMPORTENV * import an environment
890 CONFIG_CMD_INI * import data from an ini file into the env
891 CONFIG_CMD_IRQ * irqinfo
892 CONFIG_CMD_ITEST Integer/string test of 2 values
893 CONFIG_CMD_JFFS2 * JFFS2 Support
894 CONFIG_CMD_KGDB * kgdb
895 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
896 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
898 CONFIG_CMD_LOADB loadb
899 CONFIG_CMD_LOADS loads
900 CONFIG_CMD_MD5SUM * print md5 message digest
901 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
902 CONFIG_CMD_MEMINFO * Display detailed memory information
903 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
905 CONFIG_CMD_MEMTEST * mtest
906 CONFIG_CMD_MISC Misc functions like sleep etc
907 CONFIG_CMD_MMC * MMC memory mapped support
908 CONFIG_CMD_MII * MII utility commands
909 CONFIG_CMD_MTDPARTS * MTD partition support
910 CONFIG_CMD_NAND * NAND support
911 CONFIG_CMD_NET bootp, tftpboot, rarpboot
912 CONFIG_CMD_NFS NFS support
913 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
914 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
915 CONFIG_CMD_PCI * pciinfo
916 CONFIG_CMD_PCMCIA * PCMCIA support
917 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
919 CONFIG_CMD_PORTIO * Port I/O
920 CONFIG_CMD_READ * Read raw data from partition
921 CONFIG_CMD_REGINFO * Register dump
922 CONFIG_CMD_RUN run command in env variable
923 CONFIG_CMD_SANDBOX * sb command to access sandbox features
924 CONFIG_CMD_SAVES * save S record dump
925 CONFIG_CMD_SCSI * SCSI Support
926 CONFIG_CMD_SDRAM * print SDRAM configuration information
927 (requires CONFIG_CMD_I2C)
928 CONFIG_CMD_SETGETDCR Support for DCR Register access
930 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
931 CONFIG_CMD_SHA1SUM * print sha1 memory digest
932 (requires CONFIG_CMD_MEMORY)
933 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
934 CONFIG_CMD_SOURCE "source" command Support
935 CONFIG_CMD_SPI * SPI serial bus support
936 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
937 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
938 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
939 CONFIG_CMD_TIMER * access to the system tick timer
940 CONFIG_CMD_USB * USB support
941 CONFIG_CMD_CDP * Cisco Discover Protocol support
942 CONFIG_CMD_MFSL * Microblaze FSL support
943 CONFIG_CMD_XIMG Load part of Multi Image
946 EXAMPLE: If you want all functions except of network
947 support you can write:
949 #include "config_cmd_all.h"
950 #undef CONFIG_CMD_NET
953 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
955 Note: Don't enable the "icache" and "dcache" commands
956 (configuration option CONFIG_CMD_CACHE) unless you know
957 what you (and your U-Boot users) are doing. Data
958 cache cannot be enabled on systems like the 8xx or
959 8260 (where accesses to the IMMR region must be
960 uncached), and it cannot be disabled on all other
961 systems where we (mis-) use the data cache to hold an
962 initial stack and some data.
965 XXX - this list needs to get updated!
967 - Regular expression support:
969 If this variable is defined, U-Boot is linked against
970 the SLRE (Super Light Regular Expression) library,
971 which adds regex support to some commands, as for
972 example "env grep" and "setexpr".
976 If this variable is defined, U-Boot will use a device tree
977 to configure its devices, instead of relying on statically
978 compiled #defines in the board file. This option is
979 experimental and only available on a few boards. The device
980 tree is available in the global data as gd->fdt_blob.
982 U-Boot needs to get its device tree from somewhere. This can
983 be done using one of the two options below:
986 If this variable is defined, U-Boot will embed a device tree
987 binary in its image. This device tree file should be in the
988 board directory and called <soc>-<board>.dts. The binary file
989 is then picked up in board_init_f() and made available through
990 the global data structure as gd->blob.
993 If this variable is defined, U-Boot will build a device tree
994 binary. It will be called u-boot.dtb. Architecture-specific
995 code will locate it at run-time. Generally this works by:
997 cat u-boot.bin u-boot.dtb >image.bin
999 and in fact, U-Boot does this for you, creating a file called
1000 u-boot-dtb.bin which is useful in the common case. You can
1001 still use the individual files if you need something more
1006 If this variable is defined, it enables watchdog
1007 support for the SoC. There must be support in the SoC
1008 specific code for a watchdog. For the 8xx and 8260
1009 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1010 register. When supported for a specific SoC is
1011 available, then no further board specific code should
1012 be needed to use it.
1015 When using a watchdog circuitry external to the used
1016 SoC, then define this variable and provide board
1017 specific code for the "hw_watchdog_reset" function.
1020 CONFIG_VERSION_VARIABLE
1021 If this variable is defined, an environment variable
1022 named "ver" is created by U-Boot showing the U-Boot
1023 version as printed by the "version" command.
1024 Any change to this variable will be reverted at the
1029 When CONFIG_CMD_DATE is selected, the type of the RTC
1030 has to be selected, too. Define exactly one of the
1033 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1034 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1035 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1036 CONFIG_RTC_MC146818 - use MC146818 RTC
1037 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1038 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1039 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1040 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1041 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1042 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1043 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1044 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1047 Note that if the RTC uses I2C, then the I2C interface
1048 must also be configured. See I2C Support, below.
1051 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1053 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1054 chip-ngpio pairs that tell the PCA953X driver the number of
1055 pins supported by a particular chip.
1057 Note that if the GPIO device uses I2C, then the I2C interface
1058 must also be configured. See I2C Support, below.
1060 - Timestamp Support:
1062 When CONFIG_TIMESTAMP is selected, the timestamp
1063 (date and time) of an image is printed by image
1064 commands like bootm or iminfo. This option is
1065 automatically enabled when you select CONFIG_CMD_DATE .
1067 - Partition Labels (disklabels) Supported:
1068 Zero or more of the following:
1069 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1070 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1071 Intel architecture, USB sticks, etc.
1072 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1073 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1074 bootloader. Note 2TB partition limit; see
1076 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1078 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1079 CONFIG_CMD_SCSI) you must configure support for at
1080 least one non-MTD partition type as well.
1083 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1084 board configurations files but used nowhere!
1086 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1087 be performed by calling the function
1088 ide_set_reset(int reset)
1089 which has to be defined in a board specific file
1094 Set this to enable ATAPI support.
1099 Set this to enable support for disks larger than 137GB
1100 Also look at CONFIG_SYS_64BIT_LBA.
1101 Whithout these , LBA48 support uses 32bit variables and will 'only'
1102 support disks up to 2.1TB.
1104 CONFIG_SYS_64BIT_LBA:
1105 When enabled, makes the IDE subsystem use 64bit sector addresses.
1109 At the moment only there is only support for the
1110 SYM53C8XX SCSI controller; define
1111 CONFIG_SCSI_SYM53C8XX to enable it.
1113 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1114 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1115 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1116 maximum numbers of LUNs, SCSI ID's and target
1118 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1120 The environment variable 'scsidevs' is set to the number of
1121 SCSI devices found during the last scan.
1123 - NETWORK Support (PCI):
1125 Support for Intel 8254x/8257x gigabit chips.
1128 Utility code for direct access to the SPI bus on Intel 8257x.
1129 This does not do anything useful unless you set at least one
1130 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1132 CONFIG_E1000_SPI_GENERIC
1133 Allow generic access to the SPI bus on the Intel 8257x, for
1134 example with the "sspi" command.
1137 Management command for E1000 devices. When used on devices
1138 with SPI support you can reprogram the EEPROM from U-Boot.
1140 CONFIG_E1000_FALLBACK_MAC
1141 default MAC for empty EEPROM after production.
1144 Support for Intel 82557/82559/82559ER chips.
1145 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1146 write routine for first time initialisation.
1149 Support for Digital 2114x chips.
1150 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1151 modem chip initialisation (KS8761/QS6611).
1154 Support for National dp83815 chips.
1157 Support for National dp8382[01] gigabit chips.
1159 - NETWORK Support (other):
1161 CONFIG_DRIVER_AT91EMAC
1162 Support for AT91RM9200 EMAC.
1165 Define this to use reduced MII inteface
1167 CONFIG_DRIVER_AT91EMAC_QUIET
1168 If this defined, the driver is quiet.
1169 The driver doen't show link status messages.
1171 CONFIG_CALXEDA_XGMAC
1172 Support for the Calxeda XGMAC device
1175 Support for SMSC's LAN91C96 chips.
1177 CONFIG_LAN91C96_BASE
1178 Define this to hold the physical address
1179 of the LAN91C96's I/O space
1181 CONFIG_LAN91C96_USE_32_BIT
1182 Define this to enable 32 bit addressing
1185 Support for SMSC's LAN91C111 chip
1187 CONFIG_SMC91111_BASE
1188 Define this to hold the physical address
1189 of the device (I/O space)
1191 CONFIG_SMC_USE_32_BIT
1192 Define this if data bus is 32 bits
1194 CONFIG_SMC_USE_IOFUNCS
1195 Define this to use i/o functions instead of macros
1196 (some hardware wont work with macros)
1198 CONFIG_DRIVER_TI_EMAC
1199 Support for davinci emac
1201 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1202 Define this if you have more then 3 PHYs.
1205 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1207 CONFIG_FTGMAC100_EGIGA
1208 Define this to use GE link update with gigabit PHY.
1209 Define this if FTGMAC100 is connected to gigabit PHY.
1210 If your system has 10/100 PHY only, it might not occur
1211 wrong behavior. Because PHY usually return timeout or
1212 useless data when polling gigabit status and gigabit
1213 control registers. This behavior won't affect the
1214 correctnessof 10/100 link speed update.
1217 Support for SMSC's LAN911x and LAN921x chips
1220 Define this to hold the physical address
1221 of the device (I/O space)
1223 CONFIG_SMC911X_32_BIT
1224 Define this if data bus is 32 bits
1226 CONFIG_SMC911X_16_BIT
1227 Define this if data bus is 16 bits. If your processor
1228 automatically converts one 32 bit word to two 16 bit
1229 words you may also try CONFIG_SMC911X_32_BIT.
1232 Support for Renesas on-chip Ethernet controller
1234 CONFIG_SH_ETHER_USE_PORT
1235 Define the number of ports to be used
1237 CONFIG_SH_ETHER_PHY_ADDR
1238 Define the ETH PHY's address
1240 CONFIG_SH_ETHER_CACHE_WRITEBACK
1241 If this option is set, the driver enables cache flush.
1245 Support TPM devices.
1248 Support for i2c bus TPM devices. Only one device
1249 per system is supported at this time.
1251 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1252 Define the the i2c bus number for the TPM device
1254 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1255 Define the TPM's address on the i2c bus
1257 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1258 Define the burst count bytes upper limit
1260 CONFIG_TPM_ATMEL_TWI
1261 Support for Atmel TWI TPM device. Requires I2C support.
1264 Support for generic parallel port TPM devices. Only one device
1265 per system is supported at this time.
1267 CONFIG_TPM_TIS_BASE_ADDRESS
1268 Base address where the generic TPM device is mapped
1269 to. Contemporary x86 systems usually map it at
1273 Add tpm monitor functions.
1274 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1275 provides monitor access to authorized functions.
1278 Define this to enable the TPM support library which provides
1279 functional interfaces to some TPM commands.
1280 Requires support for a TPM device.
1282 CONFIG_TPM_AUTH_SESSIONS
1283 Define this to enable authorized functions in the TPM library.
1284 Requires CONFIG_TPM and CONFIG_SHA1.
1287 At the moment only the UHCI host controller is
1288 supported (PIP405, MIP405, MPC5200); define
1289 CONFIG_USB_UHCI to enable it.
1290 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1291 and define CONFIG_USB_STORAGE to enable the USB
1294 Supported are USB Keyboards and USB Floppy drives
1296 MPC5200 USB requires additional defines:
1298 for 528 MHz Clock: 0x0001bbbb
1302 for differential drivers: 0x00001000
1303 for single ended drivers: 0x00005000
1304 for differential drivers on PSC3: 0x00000100
1305 for single ended drivers on PSC3: 0x00004100
1306 CONFIG_SYS_USB_EVENT_POLL
1307 May be defined to allow interrupt polling
1308 instead of using asynchronous interrupts
1310 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1311 txfilltuning field in the EHCI controller on reset.
1313 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1314 interval for usb hub power-on delay.(minimum 100msec)
1317 Define the below if you wish to use the USB console.
1318 Once firmware is rebuilt from a serial console issue the
1319 command "setenv stdin usbtty; setenv stdout usbtty" and
1320 attach your USB cable. The Unix command "dmesg" should print
1321 it has found a new device. The environment variable usbtty
1322 can be set to gserial or cdc_acm to enable your device to
1323 appear to a USB host as a Linux gserial device or a
1324 Common Device Class Abstract Control Model serial device.
1325 If you select usbtty = gserial you should be able to enumerate
1327 # modprobe usbserial vendor=0xVendorID product=0xProductID
1328 else if using cdc_acm, simply setting the environment
1329 variable usbtty to be cdc_acm should suffice. The following
1330 might be defined in YourBoardName.h
1333 Define this to build a UDC device
1336 Define this to have a tty type of device available to
1337 talk to the UDC device
1340 Define this to enable the high speed support for usb
1341 device and usbtty. If this feature is enabled, a routine
1342 int is_usbd_high_speed(void)
1343 also needs to be defined by the driver to dynamically poll
1344 whether the enumeration has succeded at high speed or full
1347 CONFIG_SYS_CONSOLE_IS_IN_ENV
1348 Define this if you want stdin, stdout &/or stderr to
1352 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1353 Derive USB clock from external clock "blah"
1354 - CONFIG_SYS_USB_EXTC_CLK 0x02
1356 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1357 Derive USB clock from brgclk
1358 - CONFIG_SYS_USB_BRG_CLK 0x04
1360 If you have a USB-IF assigned VendorID then you may wish to
1361 define your own vendor specific values either in BoardName.h
1362 or directly in usbd_vendor_info.h. If you don't define
1363 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1364 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1365 should pretend to be a Linux device to it's target host.
1367 CONFIG_USBD_MANUFACTURER
1368 Define this string as the name of your company for
1369 - CONFIG_USBD_MANUFACTURER "my company"
1371 CONFIG_USBD_PRODUCT_NAME
1372 Define this string as the name of your product
1373 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1375 CONFIG_USBD_VENDORID
1376 Define this as your assigned Vendor ID from the USB
1377 Implementors Forum. This *must* be a genuine Vendor ID
1378 to avoid polluting the USB namespace.
1379 - CONFIG_USBD_VENDORID 0xFFFF
1381 CONFIG_USBD_PRODUCTID
1382 Define this as the unique Product ID
1384 - CONFIG_USBD_PRODUCTID 0xFFFF
1386 Some USB device drivers may need to check USB cable attachment.
1387 In this case you can enable following config in BoardName.h:
1388 CONFIG_USB_CABLE_CHECK
1389 This enables function definition:
1390 - usb_cable_connected() in include/usb.h
1391 Implementation of this function is board-specific.
1393 - ULPI Layer Support:
1394 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1395 the generic ULPI layer. The generic layer accesses the ULPI PHY
1396 via the platform viewport, so you need both the genric layer and
1397 the viewport enabled. Currently only Chipidea/ARC based
1398 viewport is supported.
1399 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1400 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1401 If your ULPI phy needs a different reference clock than the
1402 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1403 the appropriate value in Hz.
1406 The MMC controller on the Intel PXA is supported. To
1407 enable this define CONFIG_MMC. The MMC can be
1408 accessed from the boot prompt by mapping the device
1409 to physical memory similar to flash. Command line is
1410 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1411 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1414 Support for Renesas on-chip MMCIF controller
1416 CONFIG_SH_MMCIF_ADDR
1417 Define the base address of MMCIF registers
1420 Define the clock frequency for MMCIF
1422 - USB Device Firmware Update (DFU) class support:
1424 This enables the USB portion of the DFU USB class
1427 This enables the command "dfu" which is used to have
1428 U-Boot create a DFU class device via USB. This command
1429 requires that the "dfu_alt_info" environment variable be
1430 set and define the alt settings to expose to the host.
1433 This enables support for exposing (e)MMC devices via DFU.
1436 This enables support for exposing NAND devices via DFU.
1439 This enables support for exposing RAM via DFU.
1440 Note: DFU spec refer to non-volatile memory usage, but
1441 allow usages beyond the scope of spec - here RAM usage,
1442 one that would help mostly the developer.
1444 CONFIG_SYS_DFU_DATA_BUF_SIZE
1445 Dfu transfer uses a buffer before writing data to the
1446 raw storage device. Make the size (in bytes) of this buffer
1447 configurable. The size of this buffer is also configurable
1448 through the "dfu_bufsiz" environment variable.
1450 CONFIG_SYS_DFU_MAX_FILE_SIZE
1451 When updating files rather than the raw storage device,
1452 we use a static buffer to copy the file into and then write
1453 the buffer once we've been given the whole file. Define
1454 this to the maximum filesize (in bytes) for the buffer.
1455 Default is 4 MiB if undefined.
1457 - Journaling Flash filesystem support:
1458 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1459 CONFIG_JFFS2_NAND_DEV
1460 Define these for a default partition on a NAND device
1462 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1463 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1464 Define these for a default partition on a NOR device
1466 CONFIG_SYS_JFFS_CUSTOM_PART
1467 Define this to create an own partition. You have to provide a
1468 function struct part_info* jffs2_part_info(int part_num)
1470 If you define only one JFFS2 partition you may also want to
1471 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1472 to disable the command chpart. This is the default when you
1473 have not defined a custom partition
1475 - FAT(File Allocation Table) filesystem write function support:
1478 Define this to enable support for saving memory data as a
1479 file in FAT formatted partition.
1481 This will also enable the command "fatwrite" enabling the
1482 user to write files to FAT.
1484 CBFS (Coreboot Filesystem) support
1487 Define this to enable support for reading from a Coreboot
1488 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1494 Define this to enable standard (PC-Style) keyboard
1498 Standard PC keyboard driver with US (is default) and
1499 GERMAN key layout (switch via environment 'keymap=de') support.
1500 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1501 for cfb_console. Supports cursor blinking.
1504 Enables a Chrome OS keyboard using the CROS_EC interface.
1505 This uses CROS_EC to communicate with a second microcontroller
1506 which provides key scans on request.
1511 Define this to enable video support (for output to
1514 CONFIG_VIDEO_CT69000
1516 Enable Chips & Technologies 69000 Video chip
1518 CONFIG_VIDEO_SMI_LYNXEM
1519 Enable Silicon Motion SMI 712/710/810 Video chip. The
1520 video output is selected via environment 'videoout'
1521 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1524 For the CT69000 and SMI_LYNXEM drivers, videomode is
1525 selected via environment 'videomode'. Two different ways
1527 - "videomode=num" 'num' is a standard LiLo mode numbers.
1528 Following standard modes are supported (* is default):
1530 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1531 -------------+---------------------------------------------
1532 8 bits | 0x301* 0x303 0x305 0x161 0x307
1533 15 bits | 0x310 0x313 0x316 0x162 0x319
1534 16 bits | 0x311 0x314 0x317 0x163 0x31A
1535 24 bits | 0x312 0x315 0x318 ? 0x31B
1536 -------------+---------------------------------------------
1537 (i.e. setenv videomode 317; saveenv; reset;)
1539 - "videomode=bootargs" all the video parameters are parsed
1540 from the bootargs. (See drivers/video/videomodes.c)
1543 CONFIG_VIDEO_SED13806
1544 Enable Epson SED13806 driver. This driver supports 8bpp
1545 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1546 or CONFIG_VIDEO_SED13806_16BPP
1549 Enable the Freescale DIU video driver. Reference boards for
1550 SOCs that have a DIU should define this macro to enable DIU
1551 support, and should also define these other macros:
1557 CONFIG_VIDEO_SW_CURSOR
1558 CONFIG_VGA_AS_SINGLE_DEVICE
1560 CONFIG_VIDEO_BMP_LOGO
1562 The DIU driver will look for the 'video-mode' environment
1563 variable, and if defined, enable the DIU as a console during
1564 boot. See the documentation file README.video for a
1565 description of this variable.
1569 Enable the VGA video / BIOS for x86. The alternative if you
1570 are using coreboot is to use the coreboot frame buffer
1577 Define this to enable a custom keyboard support.
1578 This simply calls drv_keyboard_init() which must be
1579 defined in your board-specific files.
1580 The only board using this so far is RBC823.
1582 - LCD Support: CONFIG_LCD
1584 Define this to enable LCD support (for output to LCD
1585 display); also select one of the supported displays
1586 by defining one of these:
1590 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1592 CONFIG_NEC_NL6448AC33:
1594 NEC NL6448AC33-18. Active, color, single scan.
1596 CONFIG_NEC_NL6448BC20
1598 NEC NL6448BC20-08. 6.5", 640x480.
1599 Active, color, single scan.
1601 CONFIG_NEC_NL6448BC33_54
1603 NEC NL6448BC33-54. 10.4", 640x480.
1604 Active, color, single scan.
1608 Sharp 320x240. Active, color, single scan.
1609 It isn't 16x9, and I am not sure what it is.
1611 CONFIG_SHARP_LQ64D341
1613 Sharp LQ64D341 display, 640x480.
1614 Active, color, single scan.
1618 HLD1045 display, 640x480.
1619 Active, color, single scan.
1623 Optrex CBL50840-2 NF-FW 99 22 M5
1625 Hitachi LMG6912RPFC-00T
1629 320x240. Black & white.
1631 Normally display is black on white background; define
1632 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1634 CONFIG_LCD_ALIGNMENT
1636 Normally the LCD is page-aligned (tyically 4KB). If this is
1637 defined then the LCD will be aligned to this value instead.
1638 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1639 here, since it is cheaper to change data cache settings on
1640 a per-section basis.
1642 CONFIG_CONSOLE_SCROLL_LINES
1644 When the console need to be scrolled, this is the number of
1645 lines to scroll by. It defaults to 1. Increasing this makes
1646 the console jump but can help speed up operation when scrolling
1651 Support drawing of RLE8-compressed bitmaps on the LCD.
1655 Enables an 'i2c edid' command which can read EDID
1656 information over I2C from an attached LCD display.
1658 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1660 If this option is set, the environment is checked for
1661 a variable "splashimage". If found, the usual display
1662 of logo, copyright and system information on the LCD
1663 is suppressed and the BMP image at the address
1664 specified in "splashimage" is loaded instead. The
1665 console is redirected to the "nulldev", too. This
1666 allows for a "silent" boot where a splash screen is
1667 loaded very quickly after power-on.
1669 CONFIG_SPLASHIMAGE_GUARD
1671 If this option is set, then U-Boot will prevent the environment
1672 variable "splashimage" from being set to a problematic address
1673 (see README.displaying-bmps and README.arm-unaligned-accesses).
1674 This option is useful for targets where, due to alignment
1675 restrictions, an improperly aligned BMP image will cause a data
1676 abort. If you think you will not have problems with unaligned
1677 accesses (for example because your toolchain prevents them)
1678 there is no need to set this option.
1680 CONFIG_SPLASH_SCREEN_ALIGN
1682 If this option is set the splash image can be freely positioned
1683 on the screen. Environment variable "splashpos" specifies the
1684 position as "x,y". If a positive number is given it is used as
1685 number of pixel from left/top. If a negative number is given it
1686 is used as number of pixel from right/bottom. You can also
1687 specify 'm' for centering the image.
1690 setenv splashpos m,m
1691 => image at center of screen
1693 setenv splashpos 30,20
1694 => image at x = 30 and y = 20
1696 setenv splashpos -10,m
1697 => vertically centered image
1698 at x = dspWidth - bmpWidth - 9
1700 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1702 If this option is set, additionally to standard BMP
1703 images, gzipped BMP images can be displayed via the
1704 splashscreen support or the bmp command.
1706 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1708 If this option is set, 8-bit RLE compressed BMP images
1709 can be displayed via the splashscreen support or the
1712 - Do compresssing for memory range:
1715 If this option is set, it would use zlib deflate method
1716 to compress the specified memory at its best effort.
1718 - Compression support:
1721 Enabled by default to support gzip compressed images.
1725 If this option is set, support for bzip2 compressed
1726 images is included. If not, only uncompressed and gzip
1727 compressed images are supported.
1729 NOTE: the bzip2 algorithm requires a lot of RAM, so
1730 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1735 If this option is set, support for lzma compressed
1738 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1739 requires an amount of dynamic memory that is given by the
1742 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1744 Where lc and lp stand for, respectively, Literal context bits
1745 and Literal pos bits.
1747 This value is upper-bounded by 14MB in the worst case. Anyway,
1748 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1749 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1750 a very small buffer.
1752 Use the lzmainfo tool to determinate the lc and lp values and
1753 then calculate the amount of needed dynamic memory (ensuring
1754 the appropriate CONFIG_SYS_MALLOC_LEN value).
1758 If this option is set, support for LZO compressed images
1764 The address of PHY on MII bus.
1766 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1768 The clock frequency of the MII bus
1772 If this option is set, support for speed/duplex
1773 detection of gigabit PHY is included.
1775 CONFIG_PHY_RESET_DELAY
1777 Some PHY like Intel LXT971A need extra delay after
1778 reset before any MII register access is possible.
1779 For such PHY, set this option to the usec delay
1780 required. (minimum 300usec for LXT971A)
1782 CONFIG_PHY_CMD_DELAY (ppc4xx)
1784 Some PHY like Intel LXT971A need extra delay after
1785 command issued before MII status register can be read
1795 Define a default value for Ethernet address to use
1796 for the respective Ethernet interface, in case this
1797 is not determined automatically.
1802 Define a default value for the IP address to use for
1803 the default Ethernet interface, in case this is not
1804 determined through e.g. bootp.
1805 (Environment variable "ipaddr")
1807 - Server IP address:
1810 Defines a default value for the IP address of a TFTP
1811 server to contact when using the "tftboot" command.
1812 (Environment variable "serverip")
1814 CONFIG_KEEP_SERVERADDR
1816 Keeps the server's MAC address, in the env 'serveraddr'
1817 for passing to bootargs (like Linux's netconsole option)
1819 - Gateway IP address:
1822 Defines a default value for the IP address of the
1823 default router where packets to other networks are
1825 (Environment variable "gatewayip")
1830 Defines a default value for the subnet mask (or
1831 routing prefix) which is used to determine if an IP
1832 address belongs to the local subnet or needs to be
1833 forwarded through a router.
1834 (Environment variable "netmask")
1836 - Multicast TFTP Mode:
1839 Defines whether you want to support multicast TFTP as per
1840 rfc-2090; for example to work with atftp. Lets lots of targets
1841 tftp down the same boot image concurrently. Note: the Ethernet
1842 driver in use must provide a function: mcast() to join/leave a
1845 - BOOTP Recovery Mode:
1846 CONFIG_BOOTP_RANDOM_DELAY
1848 If you have many targets in a network that try to
1849 boot using BOOTP, you may want to avoid that all
1850 systems send out BOOTP requests at precisely the same
1851 moment (which would happen for instance at recovery
1852 from a power failure, when all systems will try to
1853 boot, thus flooding the BOOTP server. Defining
1854 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1855 inserted before sending out BOOTP requests. The
1856 following delays are inserted then:
1858 1st BOOTP request: delay 0 ... 1 sec
1859 2nd BOOTP request: delay 0 ... 2 sec
1860 3rd BOOTP request: delay 0 ... 4 sec
1862 BOOTP requests: delay 0 ... 8 sec
1864 - DHCP Advanced Options:
1865 You can fine tune the DHCP functionality by defining
1866 CONFIG_BOOTP_* symbols:
1868 CONFIG_BOOTP_SUBNETMASK
1869 CONFIG_BOOTP_GATEWAY
1870 CONFIG_BOOTP_HOSTNAME
1871 CONFIG_BOOTP_NISDOMAIN
1872 CONFIG_BOOTP_BOOTPATH
1873 CONFIG_BOOTP_BOOTFILESIZE
1876 CONFIG_BOOTP_SEND_HOSTNAME
1877 CONFIG_BOOTP_NTPSERVER
1878 CONFIG_BOOTP_TIMEOFFSET
1879 CONFIG_BOOTP_VENDOREX
1880 CONFIG_BOOTP_MAY_FAIL
1882 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1883 environment variable, not the BOOTP server.
1885 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1886 after the configured retry count, the call will fail
1887 instead of starting over. This can be used to fail over
1888 to Link-local IP address configuration if the DHCP server
1891 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1892 serverip from a DHCP server, it is possible that more
1893 than one DNS serverip is offered to the client.
1894 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1895 serverip will be stored in the additional environment
1896 variable "dnsip2". The first DNS serverip is always
1897 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1900 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1901 to do a dynamic update of a DNS server. To do this, they
1902 need the hostname of the DHCP requester.
1903 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1904 of the "hostname" environment variable is passed as
1905 option 12 to the DHCP server.
1907 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1909 A 32bit value in microseconds for a delay between
1910 receiving a "DHCP Offer" and sending the "DHCP Request".
1911 This fixes a problem with certain DHCP servers that don't
1912 respond 100% of the time to a "DHCP request". E.g. On an
1913 AT91RM9200 processor running at 180MHz, this delay needed
1914 to be *at least* 15,000 usec before a Windows Server 2003
1915 DHCP server would reply 100% of the time. I recommend at
1916 least 50,000 usec to be safe. The alternative is to hope
1917 that one of the retries will be successful but note that
1918 the DHCP timeout and retry process takes a longer than
1921 - Link-local IP address negotiation:
1922 Negotiate with other link-local clients on the local network
1923 for an address that doesn't require explicit configuration.
1924 This is especially useful if a DHCP server cannot be guaranteed
1925 to exist in all environments that the device must operate.
1927 See doc/README.link-local for more information.
1930 CONFIG_CDP_DEVICE_ID
1932 The device id used in CDP trigger frames.
1934 CONFIG_CDP_DEVICE_ID_PREFIX
1936 A two character string which is prefixed to the MAC address
1941 A printf format string which contains the ascii name of
1942 the port. Normally is set to "eth%d" which sets
1943 eth0 for the first Ethernet, eth1 for the second etc.
1945 CONFIG_CDP_CAPABILITIES
1947 A 32bit integer which indicates the device capabilities;
1948 0x00000010 for a normal host which does not forwards.
1952 An ascii string containing the version of the software.
1956 An ascii string containing the name of the platform.
1960 A 32bit integer sent on the trigger.
1962 CONFIG_CDP_POWER_CONSUMPTION
1964 A 16bit integer containing the power consumption of the
1965 device in .1 of milliwatts.
1967 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1969 A byte containing the id of the VLAN.
1971 - Status LED: CONFIG_STATUS_LED
1973 Several configurations allow to display the current
1974 status using a LED. For instance, the LED will blink
1975 fast while running U-Boot code, stop blinking as
1976 soon as a reply to a BOOTP request was received, and
1977 start blinking slow once the Linux kernel is running
1978 (supported by a status LED driver in the Linux
1979 kernel). Defining CONFIG_STATUS_LED enables this
1982 - CAN Support: CONFIG_CAN_DRIVER
1984 Defining CONFIG_CAN_DRIVER enables CAN driver support
1985 on those systems that support this (optional)
1986 feature, like the TQM8xxL modules.
1988 - I2C Support: CONFIG_SYS_I2C
1990 This enable the NEW i2c subsystem, and will allow you to use
1991 i2c commands at the u-boot command line (as long as you set
1992 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1993 based realtime clock chips or other i2c devices. See
1994 common/cmd_i2c.c for a description of the command line
1997 ported i2c driver to the new framework:
1998 - drivers/i2c/soft_i2c.c:
1999 - activate first bus with CONFIG_SYS_I2C_SOFT define
2000 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2001 for defining speed and slave address
2002 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2003 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2004 for defining speed and slave address
2005 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2006 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2007 for defining speed and slave address
2008 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2009 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2010 for defining speed and slave address
2012 - drivers/i2c/fsl_i2c.c:
2013 - activate i2c driver with CONFIG_SYS_I2C_FSL
2014 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2015 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2016 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2018 - If your board supports a second fsl i2c bus, define
2019 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2020 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2021 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2024 - drivers/i2c/tegra_i2c.c:
2025 - activate this driver with CONFIG_SYS_I2C_TEGRA
2026 - This driver adds 4 i2c buses with a fix speed from
2027 100000 and the slave addr 0!
2029 - drivers/i2c/ppc4xx_i2c.c
2030 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2031 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2032 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2034 - drivers/i2c/i2c_mxc.c
2035 - activate this driver with CONFIG_SYS_I2C_MXC
2036 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2037 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2038 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2039 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2040 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2041 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2042 If thoses defines are not set, default value is 100000
2043 for speed, and 0 for slave.
2045 - drivers/i2c/rcar_i2c.c:
2046 - activate this driver with CONFIG_SYS_I2C_RCAR
2047 - This driver adds 4 i2c buses
2049 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2050 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2051 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2052 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2053 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2054 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2055 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2056 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2057 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2061 CONFIG_SYS_NUM_I2C_BUSES
2062 Hold the number of i2c busses you want to use. If you
2063 don't use/have i2c muxes on your i2c bus, this
2064 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2067 CONFIG_SYS_I2C_DIRECT_BUS
2068 define this, if you don't use i2c muxes on your hardware.
2069 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2072 CONFIG_SYS_I2C_MAX_HOPS
2073 define how many muxes are maximal consecutively connected
2074 on one i2c bus. If you not use i2c muxes, omit this
2077 CONFIG_SYS_I2C_BUSES
2078 hold a list of busses you want to use, only used if
2079 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2080 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2081 CONFIG_SYS_NUM_I2C_BUSES = 9:
2083 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2084 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2085 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2086 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2087 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2088 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2089 {1, {I2C_NULL_HOP}}, \
2090 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2091 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2095 bus 0 on adapter 0 without a mux
2096 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2097 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2098 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2099 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2100 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2101 bus 6 on adapter 1 without a mux
2102 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2103 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2105 If you do not have i2c muxes on your board, omit this define.
2107 - Legacy I2C Support: CONFIG_HARD_I2C
2109 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2110 provides the following compelling advantages:
2112 - more than one i2c adapter is usable
2113 - approved multibus support
2114 - better i2c mux support
2116 ** Please consider updating your I2C driver now. **
2118 These enable legacy I2C serial bus commands. Defining
2119 CONFIG_HARD_I2C will include the appropriate I2C driver
2120 for the selected CPU.
2122 This will allow you to use i2c commands at the u-boot
2123 command line (as long as you set CONFIG_CMD_I2C in
2124 CONFIG_COMMANDS) and communicate with i2c based realtime
2125 clock chips. See common/cmd_i2c.c for a description of the
2126 command line interface.
2128 CONFIG_HARD_I2C selects a hardware I2C controller.
2130 There are several other quantities that must also be
2131 defined when you define CONFIG_HARD_I2C.
2133 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2134 to be the frequency (in Hz) at which you wish your i2c bus
2135 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2136 the CPU's i2c node address).
2138 Now, the u-boot i2c code for the mpc8xx
2139 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2140 and so its address should therefore be cleared to 0 (See,
2141 eg, MPC823e User's Manual p.16-473). So, set
2142 CONFIG_SYS_I2C_SLAVE to 0.
2144 CONFIG_SYS_I2C_INIT_MPC5XXX
2146 When a board is reset during an i2c bus transfer
2147 chips might think that the current transfer is still
2148 in progress. Reset the slave devices by sending start
2149 commands until the slave device responds.
2151 That's all that's required for CONFIG_HARD_I2C.
2153 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2154 then the following macros need to be defined (examples are
2155 from include/configs/lwmon.h):
2159 (Optional). Any commands necessary to enable the I2C
2160 controller or configure ports.
2162 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2166 (Only for MPC8260 CPU). The I/O port to use (the code
2167 assumes both bits are on the same port). Valid values
2168 are 0..3 for ports A..D.
2172 The code necessary to make the I2C data line active
2173 (driven). If the data line is open collector, this
2176 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2180 The code necessary to make the I2C data line tri-stated
2181 (inactive). If the data line is open collector, this
2184 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2188 Code that returns true if the I2C data line is high,
2191 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2195 If <bit> is true, sets the I2C data line high. If it
2196 is false, it clears it (low).
2198 eg: #define I2C_SDA(bit) \
2199 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2200 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2204 If <bit> is true, sets the I2C clock line high. If it
2205 is false, it clears it (low).
2207 eg: #define I2C_SCL(bit) \
2208 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2209 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2213 This delay is invoked four times per clock cycle so this
2214 controls the rate of data transfer. The data rate thus
2215 is 1 / (I2C_DELAY * 4). Often defined to be something
2218 #define I2C_DELAY udelay(2)
2220 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2222 If your arch supports the generic GPIO framework (asm/gpio.h),
2223 then you may alternatively define the two GPIOs that are to be
2224 used as SCL / SDA. Any of the previous I2C_xxx macros will
2225 have GPIO-based defaults assigned to them as appropriate.
2227 You should define these to the GPIO value as given directly to
2228 the generic GPIO functions.
2230 CONFIG_SYS_I2C_INIT_BOARD
2232 When a board is reset during an i2c bus transfer
2233 chips might think that the current transfer is still
2234 in progress. On some boards it is possible to access
2235 the i2c SCLK line directly, either by using the
2236 processor pin as a GPIO or by having a second pin
2237 connected to the bus. If this option is defined a
2238 custom i2c_init_board() routine in boards/xxx/board.c
2239 is run early in the boot sequence.
2241 CONFIG_SYS_I2C_BOARD_LATE_INIT
2243 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2244 defined a custom i2c_board_late_init() routine in
2245 boards/xxx/board.c is run AFTER the operations in i2c_init()
2246 is completed. This callpoint can be used to unreset i2c bus
2247 using CPU i2c controller register accesses for CPUs whose i2c
2248 controller provide such a method. It is called at the end of
2249 i2c_init() to allow i2c_init operations to setup the i2c bus
2250 controller on the CPU (e.g. setting bus speed & slave address).
2252 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2254 This option enables configuration of bi_iic_fast[] flags
2255 in u-boot bd_info structure based on u-boot environment
2256 variable "i2cfast". (see also i2cfast)
2258 CONFIG_I2C_MULTI_BUS
2260 This option allows the use of multiple I2C buses, each of which
2261 must have a controller. At any point in time, only one bus is
2262 active. To switch to a different bus, use the 'i2c dev' command.
2263 Note that bus numbering is zero-based.
2265 CONFIG_SYS_I2C_NOPROBES
2267 This option specifies a list of I2C devices that will be skipped
2268 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2269 is set, specify a list of bus-device pairs. Otherwise, specify
2270 a 1D array of device addresses
2273 #undef CONFIG_I2C_MULTI_BUS
2274 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2276 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2278 #define CONFIG_I2C_MULTI_BUS
2279 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2281 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2283 CONFIG_SYS_SPD_BUS_NUM
2285 If defined, then this indicates the I2C bus number for DDR SPD.
2286 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2288 CONFIG_SYS_RTC_BUS_NUM
2290 If defined, then this indicates the I2C bus number for the RTC.
2291 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2293 CONFIG_SYS_DTT_BUS_NUM
2295 If defined, then this indicates the I2C bus number for the DTT.
2296 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2298 CONFIG_SYS_I2C_DTT_ADDR:
2300 If defined, specifies the I2C address of the DTT device.
2301 If not defined, then U-Boot uses predefined value for
2302 specified DTT device.
2304 CONFIG_SOFT_I2C_READ_REPEATED_START
2306 defining this will force the i2c_read() function in
2307 the soft_i2c driver to perform an I2C repeated start
2308 between writing the address pointer and reading the
2309 data. If this define is omitted the default behaviour
2310 of doing a stop-start sequence will be used. Most I2C
2311 devices can use either method, but some require one or
2314 - SPI Support: CONFIG_SPI
2316 Enables SPI driver (so far only tested with
2317 SPI EEPROM, also an instance works with Crystal A/D and
2318 D/As on the SACSng board)
2322 Enables the driver for SPI controller on SuperH. Currently
2323 only SH7757 is supported.
2327 Enables extended (16-bit) SPI EEPROM addressing.
2328 (symmetrical to CONFIG_I2C_X)
2332 Enables a software (bit-bang) SPI driver rather than
2333 using hardware support. This is a general purpose
2334 driver that only requires three general I/O port pins
2335 (two outputs, one input) to function. If this is
2336 defined, the board configuration must define several
2337 SPI configuration items (port pins to use, etc). For
2338 an example, see include/configs/sacsng.h.
2342 Enables a hardware SPI driver for general-purpose reads
2343 and writes. As with CONFIG_SOFT_SPI, the board configuration
2344 must define a list of chip-select function pointers.
2345 Currently supported on some MPC8xxx processors. For an
2346 example, see include/configs/mpc8349emds.h.
2350 Enables the driver for the SPI controllers on i.MX and MXC
2351 SoCs. Currently i.MX31/35/51 are supported.
2353 - FPGA Support: CONFIG_FPGA
2355 Enables FPGA subsystem.
2357 CONFIG_FPGA_<vendor>
2359 Enables support for specific chip vendors.
2362 CONFIG_FPGA_<family>
2364 Enables support for FPGA family.
2365 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2369 Specify the number of FPGA devices to support.
2371 CONFIG_SYS_FPGA_PROG_FEEDBACK
2373 Enable printing of hash marks during FPGA configuration.
2375 CONFIG_SYS_FPGA_CHECK_BUSY
2377 Enable checks on FPGA configuration interface busy
2378 status by the configuration function. This option
2379 will require a board or device specific function to
2384 If defined, a function that provides delays in the FPGA
2385 configuration driver.
2387 CONFIG_SYS_FPGA_CHECK_CTRLC
2388 Allow Control-C to interrupt FPGA configuration
2390 CONFIG_SYS_FPGA_CHECK_ERROR
2392 Check for configuration errors during FPGA bitfile
2393 loading. For example, abort during Virtex II
2394 configuration if the INIT_B line goes low (which
2395 indicated a CRC error).
2397 CONFIG_SYS_FPGA_WAIT_INIT
2399 Maximum time to wait for the INIT_B line to deassert
2400 after PROB_B has been deasserted during a Virtex II
2401 FPGA configuration sequence. The default time is 500
2404 CONFIG_SYS_FPGA_WAIT_BUSY
2406 Maximum time to wait for BUSY to deassert during
2407 Virtex II FPGA configuration. The default is 5 ms.
2409 CONFIG_SYS_FPGA_WAIT_CONFIG
2411 Time to wait after FPGA configuration. The default is
2414 - Configuration Management:
2417 If defined, this string will be added to the U-Boot
2418 version information (U_BOOT_VERSION)
2420 - Vendor Parameter Protection:
2422 U-Boot considers the values of the environment
2423 variables "serial#" (Board Serial Number) and
2424 "ethaddr" (Ethernet Address) to be parameters that
2425 are set once by the board vendor / manufacturer, and
2426 protects these variables from casual modification by
2427 the user. Once set, these variables are read-only,
2428 and write or delete attempts are rejected. You can
2429 change this behaviour:
2431 If CONFIG_ENV_OVERWRITE is #defined in your config
2432 file, the write protection for vendor parameters is
2433 completely disabled. Anybody can change or delete
2436 Alternatively, if you #define _both_ CONFIG_ETHADDR
2437 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2438 Ethernet address is installed in the environment,
2439 which can be changed exactly ONCE by the user. [The
2440 serial# is unaffected by this, i. e. it remains
2443 The same can be accomplished in a more flexible way
2444 for any variable by configuring the type of access
2445 to allow for those variables in the ".flags" variable
2446 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2451 Define this variable to enable the reservation of
2452 "protected RAM", i. e. RAM which is not overwritten
2453 by U-Boot. Define CONFIG_PRAM to hold the number of
2454 kB you want to reserve for pRAM. You can overwrite
2455 this default value by defining an environment
2456 variable "pram" to the number of kB you want to
2457 reserve. Note that the board info structure will
2458 still show the full amount of RAM. If pRAM is
2459 reserved, a new environment variable "mem" will
2460 automatically be defined to hold the amount of
2461 remaining RAM in a form that can be passed as boot
2462 argument to Linux, for instance like that:
2464 setenv bootargs ... mem=\${mem}
2467 This way you can tell Linux not to use this memory,
2468 either, which results in a memory region that will
2469 not be affected by reboots.
2471 *WARNING* If your board configuration uses automatic
2472 detection of the RAM size, you must make sure that
2473 this memory test is non-destructive. So far, the
2474 following board configurations are known to be
2477 IVMS8, IVML24, SPD8xx, TQM8xxL,
2478 HERMES, IP860, RPXlite, LWMON,
2481 - Access to physical memory region (> 4GB)
2482 Some basic support is provided for operations on memory not
2483 normally accessible to U-Boot - e.g. some architectures
2484 support access to more than 4GB of memory on 32-bit
2485 machines using physical address extension or similar.
2486 Define CONFIG_PHYSMEM to access this basic support, which
2487 currently only supports clearing the memory.
2492 Define this variable to stop the system in case of a
2493 fatal error, so that you have to reset it manually.
2494 This is probably NOT a good idea for an embedded
2495 system where you want the system to reboot
2496 automatically as fast as possible, but it may be
2497 useful during development since you can try to debug
2498 the conditions that lead to the situation.
2500 CONFIG_NET_RETRY_COUNT
2502 This variable defines the number of retries for
2503 network operations like ARP, RARP, TFTP, or BOOTP
2504 before giving up the operation. If not defined, a
2505 default value of 5 is used.
2509 Timeout waiting for an ARP reply in milliseconds.
2513 Timeout in milliseconds used in NFS protocol.
2514 If you encounter "ERROR: Cannot umount" in nfs command,
2515 try longer timeout such as
2516 #define CONFIG_NFS_TIMEOUT 10000UL
2518 - Command Interpreter:
2519 CONFIG_AUTO_COMPLETE
2521 Enable auto completion of commands using TAB.
2523 Note that this feature has NOT been implemented yet
2524 for the "hush" shell.
2527 CONFIG_SYS_HUSH_PARSER
2529 Define this variable to enable the "hush" shell (from
2530 Busybox) as command line interpreter, thus enabling
2531 powerful command line syntax like
2532 if...then...else...fi conditionals or `&&' and '||'
2533 constructs ("shell scripts").
2535 If undefined, you get the old, much simpler behaviour
2536 with a somewhat smaller memory footprint.
2539 CONFIG_SYS_PROMPT_HUSH_PS2
2541 This defines the secondary prompt string, which is
2542 printed when the command interpreter needs more input
2543 to complete a command. Usually "> ".
2547 In the current implementation, the local variables
2548 space and global environment variables space are
2549 separated. Local variables are those you define by
2550 simply typing `name=value'. To access a local
2551 variable later on, you have write `$name' or
2552 `${name}'; to execute the contents of a variable
2553 directly type `$name' at the command prompt.
2555 Global environment variables are those you use
2556 setenv/printenv to work with. To run a command stored
2557 in such a variable, you need to use the run command,
2558 and you must not use the '$' sign to access them.
2560 To store commands and special characters in a
2561 variable, please use double quotation marks
2562 surrounding the whole text of the variable, instead
2563 of the backslashes before semicolons and special
2566 - Commandline Editing and History:
2567 CONFIG_CMDLINE_EDITING
2569 Enable editing and History functions for interactive
2570 commandline input operations
2572 - Default Environment:
2573 CONFIG_EXTRA_ENV_SETTINGS
2575 Define this to contain any number of null terminated
2576 strings (variable = value pairs) that will be part of
2577 the default environment compiled into the boot image.
2579 For example, place something like this in your
2580 board's config file:
2582 #define CONFIG_EXTRA_ENV_SETTINGS \
2586 Warning: This method is based on knowledge about the
2587 internal format how the environment is stored by the
2588 U-Boot code. This is NOT an official, exported
2589 interface! Although it is unlikely that this format
2590 will change soon, there is no guarantee either.
2591 You better know what you are doing here.
2593 Note: overly (ab)use of the default environment is
2594 discouraged. Make sure to check other ways to preset
2595 the environment like the "source" command or the
2598 CONFIG_ENV_VARS_UBOOT_CONFIG
2600 Define this in order to add variables describing the
2601 U-Boot build configuration to the default environment.
2602 These will be named arch, cpu, board, vendor, and soc.
2604 Enabling this option will cause the following to be defined:
2612 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2614 Define this in order to add variables describing certain
2615 run-time determined information about the hardware to the
2616 environment. These will be named board_name, board_rev.
2618 CONFIG_DELAY_ENVIRONMENT
2620 Normally the environment is loaded when the board is
2621 intialised so that it is available to U-Boot. This inhibits
2622 that so that the environment is not available until
2623 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2624 this is instead controlled by the value of
2625 /config/load-environment.
2627 - DataFlash Support:
2628 CONFIG_HAS_DATAFLASH
2630 Defining this option enables DataFlash features and
2631 allows to read/write in Dataflash via the standard
2634 - Serial Flash support
2637 Defining this option enables SPI flash commands
2638 'sf probe/read/write/erase/update'.
2640 Usage requires an initial 'probe' to define the serial
2641 flash parameters, followed by read/write/erase/update
2644 The following defaults may be provided by the platform
2645 to handle the common case when only a single serial
2646 flash is present on the system.
2648 CONFIG_SF_DEFAULT_BUS Bus identifier
2649 CONFIG_SF_DEFAULT_CS Chip-select
2650 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2651 CONFIG_SF_DEFAULT_SPEED in Hz
2655 Define this option to include a destructive SPI flash
2658 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2660 Define this option to use the Bank addr/Extended addr
2661 support on SPI flashes which has size > 16Mbytes.
2663 - SystemACE Support:
2666 Adding this option adds support for Xilinx SystemACE
2667 chips attached via some sort of local bus. The address
2668 of the chip must also be defined in the
2669 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2671 #define CONFIG_SYSTEMACE
2672 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2674 When SystemACE support is added, the "ace" device type
2675 becomes available to the fat commands, i.e. fatls.
2677 - TFTP Fixed UDP Port:
2680 If this is defined, the environment variable tftpsrcp
2681 is used to supply the TFTP UDP source port value.
2682 If tftpsrcp isn't defined, the normal pseudo-random port
2683 number generator is used.
2685 Also, the environment variable tftpdstp is used to supply
2686 the TFTP UDP destination port value. If tftpdstp isn't
2687 defined, the normal port 69 is used.
2689 The purpose for tftpsrcp is to allow a TFTP server to
2690 blindly start the TFTP transfer using the pre-configured
2691 target IP address and UDP port. This has the effect of
2692 "punching through" the (Windows XP) firewall, allowing
2693 the remainder of the TFTP transfer to proceed normally.
2694 A better solution is to properly configure the firewall,
2695 but sometimes that is not allowed.
2700 This enables a generic 'hash' command which can produce
2701 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2705 Enable the hash verify command (hash -v). This adds to code
2708 CONFIG_SHA1 - support SHA1 hashing
2709 CONFIG_SHA256 - support SHA256 hashing
2711 Note: There is also a sha1sum command, which should perhaps
2712 be deprecated in favour of 'hash sha1'.
2714 - Freescale i.MX specific commands:
2715 CONFIG_CMD_HDMIDETECT
2716 This enables 'hdmidet' command which returns true if an
2717 HDMI monitor is detected. This command is i.MX 6 specific.
2720 This enables the 'bmode' (bootmode) command for forcing
2721 a boot from specific media.
2723 This is useful for forcing the ROM's usb downloader to
2724 activate upon a watchdog reset which is nice when iterating
2725 on U-Boot. Using the reset button or running bmode normal
2726 will set it back to normal. This command currently
2727 supports i.MX53 and i.MX6.
2732 This enables the RSA algorithm used for FIT image verification
2733 in U-Boot. See doc/uImage/signature for more information.
2735 The signing part is build into mkimage regardless of this
2739 - Show boot progress:
2740 CONFIG_SHOW_BOOT_PROGRESS
2742 Defining this option allows to add some board-
2743 specific code (calling a user-provided function
2744 "show_boot_progress(int)") that enables you to show
2745 the system's boot progress on some display (for
2746 example, some LED's) on your board. At the moment,
2747 the following checkpoints are implemented:
2749 - Detailed boot stage timing
2751 Define this option to get detailed timing of each stage
2752 of the boot process.
2754 CONFIG_BOOTSTAGE_USER_COUNT
2755 This is the number of available user bootstage records.
2756 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2757 a new ID will be allocated from this stash. If you exceed
2758 the limit, recording will stop.
2760 CONFIG_BOOTSTAGE_REPORT
2761 Define this to print a report before boot, similar to this:
2763 Timer summary in microseconds:
2766 3,575,678 3,575,678 board_init_f start
2767 3,575,695 17 arch_cpu_init A9
2768 3,575,777 82 arch_cpu_init done
2769 3,659,598 83,821 board_init_r start
2770 3,910,375 250,777 main_loop
2771 29,916,167 26,005,792 bootm_start
2772 30,361,327 445,160 start_kernel
2774 CONFIG_CMD_BOOTSTAGE
2775 Add a 'bootstage' command which supports printing a report
2776 and un/stashing of bootstage data.
2778 CONFIG_BOOTSTAGE_FDT
2779 Stash the bootstage information in the FDT. A root 'bootstage'
2780 node is created with each bootstage id as a child. Each child
2781 has a 'name' property and either 'mark' containing the
2782 mark time in microsecond, or 'accum' containing the
2783 accumulated time for that bootstage id in microseconds.
2788 name = "board_init_f";
2797 Code in the Linux kernel can find this in /proc/devicetree.
2799 Legacy uImage format:
2802 1 common/cmd_bootm.c before attempting to boot an image
2803 -1 common/cmd_bootm.c Image header has bad magic number
2804 2 common/cmd_bootm.c Image header has correct magic number
2805 -2 common/cmd_bootm.c Image header has bad checksum
2806 3 common/cmd_bootm.c Image header has correct checksum
2807 -3 common/cmd_bootm.c Image data has bad checksum
2808 4 common/cmd_bootm.c Image data has correct checksum
2809 -4 common/cmd_bootm.c Image is for unsupported architecture
2810 5 common/cmd_bootm.c Architecture check OK
2811 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2812 6 common/cmd_bootm.c Image Type check OK
2813 -6 common/cmd_bootm.c gunzip uncompression error
2814 -7 common/cmd_bootm.c Unimplemented compression type
2815 7 common/cmd_bootm.c Uncompression OK
2816 8 common/cmd_bootm.c No uncompress/copy overwrite error
2817 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2819 9 common/image.c Start initial ramdisk verification
2820 -10 common/image.c Ramdisk header has bad magic number
2821 -11 common/image.c Ramdisk header has bad checksum
2822 10 common/image.c Ramdisk header is OK
2823 -12 common/image.c Ramdisk data has bad checksum
2824 11 common/image.c Ramdisk data has correct checksum
2825 12 common/image.c Ramdisk verification complete, start loading
2826 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2827 13 common/image.c Start multifile image verification
2828 14 common/image.c No initial ramdisk, no multifile, continue.
2830 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2832 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2833 -31 post/post.c POST test failed, detected by post_output_backlog()
2834 -32 post/post.c POST test failed, detected by post_run_single()
2836 34 common/cmd_doc.c before loading a Image from a DOC device
2837 -35 common/cmd_doc.c Bad usage of "doc" command
2838 35 common/cmd_doc.c correct usage of "doc" command
2839 -36 common/cmd_doc.c No boot device
2840 36 common/cmd_doc.c correct boot device
2841 -37 common/cmd_doc.c Unknown Chip ID on boot device
2842 37 common/cmd_doc.c correct chip ID found, device available
2843 -38 common/cmd_doc.c Read Error on boot device
2844 38 common/cmd_doc.c reading Image header from DOC device OK
2845 -39 common/cmd_doc.c Image header has bad magic number
2846 39 common/cmd_doc.c Image header has correct magic number
2847 -40 common/cmd_doc.c Error reading Image from DOC device
2848 40 common/cmd_doc.c Image header has correct magic number
2849 41 common/cmd_ide.c before loading a Image from a IDE device
2850 -42 common/cmd_ide.c Bad usage of "ide" command
2851 42 common/cmd_ide.c correct usage of "ide" command
2852 -43 common/cmd_ide.c No boot device
2853 43 common/cmd_ide.c boot device found
2854 -44 common/cmd_ide.c Device not available
2855 44 common/cmd_ide.c Device available
2856 -45 common/cmd_ide.c wrong partition selected
2857 45 common/cmd_ide.c partition selected
2858 -46 common/cmd_ide.c Unknown partition table
2859 46 common/cmd_ide.c valid partition table found
2860 -47 common/cmd_ide.c Invalid partition type
2861 47 common/cmd_ide.c correct partition type
2862 -48 common/cmd_ide.c Error reading Image Header on boot device
2863 48 common/cmd_ide.c reading Image Header from IDE device OK
2864 -49 common/cmd_ide.c Image header has bad magic number
2865 49 common/cmd_ide.c Image header has correct magic number
2866 -50 common/cmd_ide.c Image header has bad checksum
2867 50 common/cmd_ide.c Image header has correct checksum
2868 -51 common/cmd_ide.c Error reading Image from IDE device
2869 51 common/cmd_ide.c reading Image from IDE device OK
2870 52 common/cmd_nand.c before loading a Image from a NAND device
2871 -53 common/cmd_nand.c Bad usage of "nand" command
2872 53 common/cmd_nand.c correct usage of "nand" command
2873 -54 common/cmd_nand.c No boot device
2874 54 common/cmd_nand.c boot device found
2875 -55 common/cmd_nand.c Unknown Chip ID on boot device
2876 55 common/cmd_nand.c correct chip ID found, device available
2877 -56 common/cmd_nand.c Error reading Image Header on boot device
2878 56 common/cmd_nand.c reading Image Header from NAND device OK
2879 -57 common/cmd_nand.c Image header has bad magic number
2880 57 common/cmd_nand.c Image header has correct magic number
2881 -58 common/cmd_nand.c Error reading Image from NAND device
2882 58 common/cmd_nand.c reading Image from NAND device OK
2884 -60 common/env_common.c Environment has a bad CRC, using default
2886 64 net/eth.c starting with Ethernet configuration.
2887 -64 net/eth.c no Ethernet found.
2888 65 net/eth.c Ethernet found.
2890 -80 common/cmd_net.c usage wrong
2891 80 common/cmd_net.c before calling NetLoop()
2892 -81 common/cmd_net.c some error in NetLoop() occurred
2893 81 common/cmd_net.c NetLoop() back without error
2894 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2895 82 common/cmd_net.c trying automatic boot
2896 83 common/cmd_net.c running "source" command
2897 -83 common/cmd_net.c some error in automatic boot or "source" command
2898 84 common/cmd_net.c end without errors
2903 100 common/cmd_bootm.c Kernel FIT Image has correct format
2904 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2905 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2906 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2907 102 common/cmd_bootm.c Kernel unit name specified
2908 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2909 103 common/cmd_bootm.c Found configuration node
2910 104 common/cmd_bootm.c Got kernel subimage node offset
2911 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2912 105 common/cmd_bootm.c Kernel subimage hash verification OK
2913 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2914 106 common/cmd_bootm.c Architecture check OK
2915 -106 common/cmd_bootm.c Kernel subimage has wrong type
2916 107 common/cmd_bootm.c Kernel subimage type OK
2917 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2918 108 common/cmd_bootm.c Got kernel subimage data/size
2919 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2920 -109 common/cmd_bootm.c Can't get kernel subimage type
2921 -110 common/cmd_bootm.c Can't get kernel subimage comp
2922 -111 common/cmd_bootm.c Can't get kernel subimage os
2923 -112 common/cmd_bootm.c Can't get kernel subimage load address
2924 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2926 120 common/image.c Start initial ramdisk verification
2927 -120 common/image.c Ramdisk FIT image has incorrect format
2928 121 common/image.c Ramdisk FIT image has correct format
2929 122 common/image.c No ramdisk subimage unit name, using configuration
2930 -122 common/image.c Can't get configuration for ramdisk subimage
2931 123 common/image.c Ramdisk unit name specified
2932 -124 common/image.c Can't get ramdisk subimage node offset
2933 125 common/image.c Got ramdisk subimage node offset
2934 -125 common/image.c Ramdisk subimage hash verification failed
2935 126 common/image.c Ramdisk subimage hash verification OK
2936 -126 common/image.c Ramdisk subimage for unsupported architecture
2937 127 common/image.c Architecture check OK
2938 -127 common/image.c Can't get ramdisk subimage data/size
2939 128 common/image.c Got ramdisk subimage data/size
2940 129 common/image.c Can't get ramdisk load address
2941 -129 common/image.c Got ramdisk load address
2943 -130 common/cmd_doc.c Incorrect FIT image format
2944 131 common/cmd_doc.c FIT image format OK
2946 -140 common/cmd_ide.c Incorrect FIT image format
2947 141 common/cmd_ide.c FIT image format OK
2949 -150 common/cmd_nand.c Incorrect FIT image format
2950 151 common/cmd_nand.c FIT image format OK
2952 - FIT image support:
2954 Enable support for the FIT uImage format.
2956 CONFIG_FIT_BEST_MATCH
2957 When no configuration is explicitly selected, default to the
2958 one whose fdt's compatibility field best matches that of
2959 U-Boot itself. A match is considered "best" if it matches the
2960 most specific compatibility entry of U-Boot's fdt's root node.
2961 The order of entries in the configuration's fdt is ignored.
2963 CONFIG_FIT_SIGNATURE
2964 This option enables signature verification of FIT uImages,
2965 using a hash signed and verified using RSA. See
2966 doc/uImage.FIT/signature.txt for more details.
2968 - Standalone program support:
2969 CONFIG_STANDALONE_LOAD_ADDR
2971 This option defines a board specific value for the
2972 address where standalone program gets loaded, thus
2973 overwriting the architecture dependent default
2976 - Frame Buffer Address:
2979 Define CONFIG_FB_ADDR if you want to use specific
2980 address for frame buffer. This is typically the case
2981 when using a graphics controller has separate video
2982 memory. U-Boot will then place the frame buffer at
2983 the given address instead of dynamically reserving it
2984 in system RAM by calling lcd_setmem(), which grabs
2985 the memory for the frame buffer depending on the
2986 configured panel size.
2988 Please see board_init_f function.
2990 - Automatic software updates via TFTP server
2992 CONFIG_UPDATE_TFTP_CNT_MAX
2993 CONFIG_UPDATE_TFTP_MSEC_MAX
2995 These options enable and control the auto-update feature;
2996 for a more detailed description refer to doc/README.update.
2998 - MTD Support (mtdparts command, UBI support)
3001 Adds the MTD device infrastructure from the Linux kernel.
3002 Needed for mtdparts command support.
3004 CONFIG_MTD_PARTITIONS
3006 Adds the MTD partitioning infrastructure from the Linux
3007 kernel. Needed for UBI support.
3012 Adds commands for interacting with MTD partitions formatted
3013 with the UBI flash translation layer
3015 Requires also defining CONFIG_RBTREE
3017 CONFIG_UBI_SILENCE_MSG
3019 Make the verbose messages from UBI stop printing. This leaves
3020 warnings and errors enabled.
3025 Adds commands for interacting with UBI volumes formatted as
3026 UBIFS. UBIFS is read-only in u-boot.
3028 Requires UBI support as well as CONFIG_LZO
3030 CONFIG_UBIFS_SILENCE_MSG
3032 Make the verbose messages from UBIFS stop printing. This leaves
3033 warnings and errors enabled.
3037 Enable building of SPL globally.
3040 LDSCRIPT for linking the SPL binary.
3042 CONFIG_SPL_MAX_FOOTPRINT
3043 Maximum size in memory allocated to the SPL, BSS included.
3044 When defined, the linker checks that the actual memory
3045 used by SPL from _start to __bss_end does not exceed it.
3046 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3047 must not be both defined at the same time.
3050 Maximum size of the SPL image (text, data, rodata, and
3051 linker lists sections), BSS excluded.
3052 When defined, the linker checks that the actual size does
3055 CONFIG_SPL_TEXT_BASE
3056 TEXT_BASE for linking the SPL binary.
3058 CONFIG_SPL_RELOC_TEXT_BASE
3059 Address to relocate to. If unspecified, this is equal to
3060 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3062 CONFIG_SPL_BSS_START_ADDR
3063 Link address for the BSS within the SPL binary.
3065 CONFIG_SPL_BSS_MAX_SIZE
3066 Maximum size in memory allocated to the SPL BSS.
3067 When defined, the linker checks that the actual memory used
3068 by SPL from __bss_start to __bss_end does not exceed it.
3069 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3070 must not be both defined at the same time.
3073 Adress of the start of the stack SPL will use
3075 CONFIG_SPL_RELOC_STACK
3076 Adress of the start of the stack SPL will use after
3077 relocation. If unspecified, this is equal to
3080 CONFIG_SYS_SPL_MALLOC_START
3081 Starting address of the malloc pool used in SPL.
3083 CONFIG_SYS_SPL_MALLOC_SIZE
3084 The size of the malloc pool used in SPL.
3086 CONFIG_SPL_FRAMEWORK
3087 Enable the SPL framework under common/. This framework
3088 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3089 NAND loading of the Linux Kernel.
3091 CONFIG_SPL_DISPLAY_PRINT
3092 For ARM, enable an optional function to print more information
3093 about the running system.
3095 CONFIG_SPL_INIT_MINIMAL
3096 Arch init code should be built for a very small image
3098 CONFIG_SPL_LIBCOMMON_SUPPORT
3099 Support for common/libcommon.o in SPL binary
3101 CONFIG_SPL_LIBDISK_SUPPORT
3102 Support for disk/libdisk.o in SPL binary
3104 CONFIG_SPL_I2C_SUPPORT
3105 Support for drivers/i2c/libi2c.o in SPL binary
3107 CONFIG_SPL_GPIO_SUPPORT
3108 Support for drivers/gpio/libgpio.o in SPL binary
3110 CONFIG_SPL_MMC_SUPPORT
3111 Support for drivers/mmc/libmmc.o in SPL binary
3113 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3114 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3115 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3116 Address, size and partition on the MMC to load U-Boot from
3117 when the MMC is being used in raw mode.
3119 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3120 Sector to load kernel uImage from when MMC is being
3121 used in raw mode (for Falcon mode)
3123 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3124 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3125 Sector and number of sectors to load kernel argument
3126 parameters from when MMC is being used in raw mode
3129 CONFIG_SPL_FAT_SUPPORT
3130 Support for fs/fat/libfat.o in SPL binary
3132 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3133 Filename to read to load U-Boot when reading from FAT
3135 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3136 Filename to read to load kernel uImage when reading
3137 from FAT (for Falcon mode)
3139 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3140 Filename to read to load kernel argument parameters
3141 when reading from FAT (for Falcon mode)
3143 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3144 Set this for NAND SPL on PPC mpc83xx targets, so that
3145 start.S waits for the rest of the SPL to load before
3146 continuing (the hardware starts execution after just
3147 loading the first page rather than the full 4K).
3149 CONFIG_SPL_NAND_BASE
3150 Include nand_base.c in the SPL. Requires
3151 CONFIG_SPL_NAND_DRIVERS.
3153 CONFIG_SPL_NAND_DRIVERS
3154 SPL uses normal NAND drivers, not minimal drivers.
3157 Include standard software ECC in the SPL
3159 CONFIG_SPL_NAND_SIMPLE
3160 Support for NAND boot using simple NAND drivers that
3161 expose the cmd_ctrl() interface.
3163 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3164 Set for the SPL on PPC mpc8xxx targets, support for
3165 arch/powerpc/cpu/mpc8xxx/ddr/libddr.o in SPL binary.
3167 CONFIG_SPL_COMMON_INIT_DDR
3168 Set for common ddr init with serial presence detect in
3171 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3172 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3173 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3174 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3175 CONFIG_SYS_NAND_ECCBYTES
3176 Defines the size and behavior of the NAND that SPL uses
3179 CONFIG_SYS_NAND_U_BOOT_OFFS
3180 Location in NAND to read U-Boot from
3182 CONFIG_SYS_NAND_U_BOOT_DST
3183 Location in memory to load U-Boot to
3185 CONFIG_SYS_NAND_U_BOOT_SIZE
3186 Size of image to load
3188 CONFIG_SYS_NAND_U_BOOT_START
3189 Entry point in loaded image to jump to
3191 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3192 Define this if you need to first read the OOB and then the
3193 data. This is used for example on davinci plattforms.
3195 CONFIG_SPL_OMAP3_ID_NAND
3196 Support for an OMAP3-specific set of functions to return the
3197 ID and MFR of the first attached NAND chip, if present.
3199 CONFIG_SPL_SERIAL_SUPPORT
3200 Support for drivers/serial/libserial.o in SPL binary
3202 CONFIG_SPL_SPI_FLASH_SUPPORT
3203 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3205 CONFIG_SPL_SPI_SUPPORT
3206 Support for drivers/spi/libspi.o in SPL binary
3208 CONFIG_SPL_RAM_DEVICE
3209 Support for running image already present in ram, in SPL binary
3211 CONFIG_SPL_LIBGENERIC_SUPPORT
3212 Support for lib/libgeneric.o in SPL binary
3214 CONFIG_SPL_ENV_SUPPORT
3215 Support for the environment operating in SPL binary
3217 CONFIG_SPL_NET_SUPPORT
3218 Support for the net/libnet.o in SPL binary.
3219 It conflicts with SPL env from storage medium specified by
3220 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3223 Image offset to which the SPL should be padded before appending
3224 the SPL payload. By default, this is defined as
3225 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3226 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3227 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3230 Final target image containing SPL and payload. Some SPLs
3231 use an arch-specific makefile fragment instead, for
3232 example if more than one image needs to be produced.
3234 CONFIG_FIT_SPL_PRINT
3235 Printing information about a FIT image adds quite a bit of
3236 code to SPL. So this is normally disabled in SPL. Use this
3237 option to re-enable it. This will affect the output of the
3238 bootm command when booting a FIT image.
3242 Enable building of TPL globally.
3245 Image offset to which the TPL should be padded before appending
3246 the TPL payload. By default, this is defined as
3247 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3248 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3249 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3254 [so far only for SMDK2400 boards]
3256 - Modem support enable:
3257 CONFIG_MODEM_SUPPORT
3259 - RTS/CTS Flow control enable:
3262 - Modem debug support:
3263 CONFIG_MODEM_SUPPORT_DEBUG
3265 Enables debugging stuff (char screen[1024], dbg())
3266 for modem support. Useful only with BDI2000.
3268 - Interrupt support (PPC):
3270 There are common interrupt_init() and timer_interrupt()
3271 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3272 for CPU specific initialization. interrupt_init_cpu()
3273 should set decrementer_count to appropriate value. If
3274 CPU resets decrementer automatically after interrupt
3275 (ppc4xx) it should set decrementer_count to zero.
3276 timer_interrupt() calls timer_interrupt_cpu() for CPU
3277 specific handling. If board has watchdog / status_led
3278 / other_activity_monitor it works automatically from
3279 general timer_interrupt().
3283 In the target system modem support is enabled when a
3284 specific key (key combination) is pressed during
3285 power-on. Otherwise U-Boot will boot normally
3286 (autoboot). The key_pressed() function is called from
3287 board_init(). Currently key_pressed() is a dummy
3288 function, returning 1 and thus enabling modem
3291 If there are no modem init strings in the
3292 environment, U-Boot proceed to autoboot; the
3293 previous output (banner, info printfs) will be
3296 See also: doc/README.Modem
3298 Board initialization settings:
3299 ------------------------------
3301 During Initialization u-boot calls a number of board specific functions
3302 to allow the preparation of board specific prerequisites, e.g. pin setup
3303 before drivers are initialized. To enable these callbacks the
3304 following configuration macros have to be defined. Currently this is
3305 architecture specific, so please check arch/your_architecture/lib/board.c
3306 typically in board_init_f() and board_init_r().
3308 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3309 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3310 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3311 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3313 Configuration Settings:
3314 -----------------------
3316 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3317 undefine this when you're short of memory.
3319 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3320 width of the commands listed in the 'help' command output.
3322 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3323 prompt for user input.
3325 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3327 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3329 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3331 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3332 the application (usually a Linux kernel) when it is
3335 - CONFIG_SYS_BAUDRATE_TABLE:
3336 List of legal baudrate settings for this board.
3338 - CONFIG_SYS_CONSOLE_INFO_QUIET
3339 Suppress display of console information at boot.
3341 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3342 If the board specific function
3343 extern int overwrite_console (void);
3344 returns 1, the stdin, stderr and stdout are switched to the
3345 serial port, else the settings in the environment are used.
3347 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3348 Enable the call to overwrite_console().
3350 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3351 Enable overwrite of previous console environment settings.
3353 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3354 Begin and End addresses of the area used by the
3357 - CONFIG_SYS_ALT_MEMTEST:
3358 Enable an alternate, more extensive memory test.
3360 - CONFIG_SYS_MEMTEST_SCRATCH:
3361 Scratch address used by the alternate memory test
3362 You only need to set this if address zero isn't writeable
3364 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3365 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3366 this specified memory area will get subtracted from the top
3367 (end) of RAM and won't get "touched" at all by U-Boot. By
3368 fixing up gd->ram_size the Linux kernel should gets passed
3369 the now "corrected" memory size and won't touch it either.
3370 This should work for arch/ppc and arch/powerpc. Only Linux
3371 board ports in arch/powerpc with bootwrapper support that
3372 recalculate the memory size from the SDRAM controller setup
3373 will have to get fixed in Linux additionally.
3375 This option can be used as a workaround for the 440EPx/GRx
3376 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3379 WARNING: Please make sure that this value is a multiple of
3380 the Linux page size (normally 4k). If this is not the case,
3381 then the end address of the Linux memory will be located at a
3382 non page size aligned address and this could cause major
3385 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3386 Enable temporary baudrate change while serial download
3388 - CONFIG_SYS_SDRAM_BASE:
3389 Physical start address of SDRAM. _Must_ be 0 here.
3391 - CONFIG_SYS_MBIO_BASE:
3392 Physical start address of Motherboard I/O (if using a
3395 - CONFIG_SYS_FLASH_BASE:
3396 Physical start address of Flash memory.
3398 - CONFIG_SYS_MONITOR_BASE:
3399 Physical start address of boot monitor code (set by
3400 make config files to be same as the text base address
3401 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3402 CONFIG_SYS_FLASH_BASE when booting from flash.
3404 - CONFIG_SYS_MONITOR_LEN:
3405 Size of memory reserved for monitor code, used to
3406 determine _at_compile_time_ (!) if the environment is
3407 embedded within the U-Boot image, or in a separate
3410 - CONFIG_SYS_MALLOC_LEN:
3411 Size of DRAM reserved for malloc() use.
3413 - CONFIG_SYS_BOOTM_LEN:
3414 Normally compressed uImages are limited to an
3415 uncompressed size of 8 MBytes. If this is not enough,
3416 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3417 to adjust this setting to your needs.
3419 - CONFIG_SYS_BOOTMAPSZ:
3420 Maximum size of memory mapped by the startup code of
3421 the Linux kernel; all data that must be processed by
3422 the Linux kernel (bd_info, boot arguments, FDT blob if
3423 used) must be put below this limit, unless "bootm_low"
3424 environment variable is defined and non-zero. In such case
3425 all data for the Linux kernel must be between "bootm_low"
3426 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3427 variable "bootm_mapsize" will override the value of
3428 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3429 then the value in "bootm_size" will be used instead.
3431 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3432 Enable initrd_high functionality. If defined then the
3433 initrd_high feature is enabled and the bootm ramdisk subcommand
3436 - CONFIG_SYS_BOOT_GET_CMDLINE:
3437 Enables allocating and saving kernel cmdline in space between
3438 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3440 - CONFIG_SYS_BOOT_GET_KBD:
3441 Enables allocating and saving a kernel copy of the bd_info in
3442 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3444 - CONFIG_SYS_MAX_FLASH_BANKS:
3445 Max number of Flash memory banks
3447 - CONFIG_SYS_MAX_FLASH_SECT:
3448 Max number of sectors on a Flash chip
3450 - CONFIG_SYS_FLASH_ERASE_TOUT:
3451 Timeout for Flash erase operations (in ms)
3453 - CONFIG_SYS_FLASH_WRITE_TOUT:
3454 Timeout for Flash write operations (in ms)
3456 - CONFIG_SYS_FLASH_LOCK_TOUT
3457 Timeout for Flash set sector lock bit operation (in ms)
3459 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3460 Timeout for Flash clear lock bits operation (in ms)
3462 - CONFIG_SYS_FLASH_PROTECTION
3463 If defined, hardware flash sectors protection is used
3464 instead of U-Boot software protection.
3466 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3468 Enable TFTP transfers directly to flash memory;
3469 without this option such a download has to be
3470 performed in two steps: (1) download to RAM, and (2)
3471 copy from RAM to flash.
3473 The two-step approach is usually more reliable, since
3474 you can check if the download worked before you erase
3475 the flash, but in some situations (when system RAM is
3476 too limited to allow for a temporary copy of the
3477 downloaded image) this option may be very useful.
3479 - CONFIG_SYS_FLASH_CFI:
3480 Define if the flash driver uses extra elements in the
3481 common flash structure for storing flash geometry.
3483 - CONFIG_FLASH_CFI_DRIVER
3484 This option also enables the building of the cfi_flash driver
3485 in the drivers directory
3487 - CONFIG_FLASH_CFI_MTD
3488 This option enables the building of the cfi_mtd driver
3489 in the drivers directory. The driver exports CFI flash
3492 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3493 Use buffered writes to flash.
3495 - CONFIG_FLASH_SPANSION_S29WS_N
3496 s29ws-n MirrorBit flash has non-standard addresses for buffered
3499 - CONFIG_SYS_FLASH_QUIET_TEST
3500 If this option is defined, the common CFI flash doesn't
3501 print it's warning upon not recognized FLASH banks. This
3502 is useful, if some of the configured banks are only
3503 optionally available.
3505 - CONFIG_FLASH_SHOW_PROGRESS
3506 If defined (must be an integer), print out countdown
3507 digits and dots. Recommended value: 45 (9..1) for 80
3508 column displays, 15 (3..1) for 40 column displays.
3510 - CONFIG_FLASH_VERIFY
3511 If defined, the content of the flash (destination) is compared
3512 against the source after the write operation. An error message
3513 will be printed when the contents are not identical.
3514 Please note that this option is useless in nearly all cases,
3515 since such flash programming errors usually are detected earlier
3516 while unprotecting/erasing/programming. Please only enable
3517 this option if you really know what you are doing.
3519 - CONFIG_SYS_RX_ETH_BUFFER:
3520 Defines the number of Ethernet receive buffers. On some
3521 Ethernet controllers it is recommended to set this value
3522 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3523 buffers can be full shortly after enabling the interface
3524 on high Ethernet traffic.
3525 Defaults to 4 if not defined.
3527 - CONFIG_ENV_MAX_ENTRIES
3529 Maximum number of entries in the hash table that is used
3530 internally to store the environment settings. The default
3531 setting is supposed to be generous and should work in most
3532 cases. This setting can be used to tune behaviour; see
3533 lib/hashtable.c for details.
3535 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3536 - CONFIG_ENV_FLAGS_LIST_STATIC
3537 Enable validation of the values given to environment variables when
3538 calling env set. Variables can be restricted to only decimal,
3539 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3540 the variables can also be restricted to IP address or MAC address.
3542 The format of the list is:
3543 type_attribute = [s|d|x|b|i|m]
3544 access_atribute = [a|r|o|c]
3545 attributes = type_attribute[access_atribute]
3546 entry = variable_name[:attributes]
3549 The type attributes are:
3550 s - String (default)
3553 b - Boolean ([1yYtT|0nNfF])
3557 The access attributes are:
3563 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3564 Define this to a list (string) to define the ".flags"
3565 envirnoment variable in the default or embedded environment.
3567 - CONFIG_ENV_FLAGS_LIST_STATIC
3568 Define this to a list (string) to define validation that
3569 should be done if an entry is not found in the ".flags"
3570 environment variable. To override a setting in the static
3571 list, simply add an entry for the same variable name to the
3574 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3575 If defined, don't allow the -f switch to env set override variable
3578 - CONFIG_SYS_GENERIC_BOARD
3579 This selects the architecture-generic board system instead of the
3580 architecture-specific board files. It is intended to move boards
3581 to this new framework over time. Defining this will disable the
3582 arch/foo/lib/board.c file and use common/board_f.c and
3583 common/board_r.c instead. To use this option your architecture
3584 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3585 its config.mk file). If you find problems enabling this option on
3586 your board please report the problem and send patches!
3588 - CONFIG_SYS_SYM_OFFSETS
3589 This is set by architectures that use offsets for link symbols
3590 instead of absolute values. So bss_start is obtained using an
3591 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3592 directly. You should not need to touch this setting.
3594 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3595 This is set by OMAP boards for the max time that reset should
3596 be asserted. See doc/README.omap-reset-time for details on how
3597 the value can be calulated on a given board.
3599 The following definitions that deal with the placement and management
3600 of environment data (variable area); in general, we support the
3601 following configurations:
3603 - CONFIG_BUILD_ENVCRC:
3605 Builds up envcrc with the target environment so that external utils
3606 may easily extract it and embed it in final U-Boot images.
3608 - CONFIG_ENV_IS_IN_FLASH:
3610 Define this if the environment is in flash memory.
3612 a) The environment occupies one whole flash sector, which is
3613 "embedded" in the text segment with the U-Boot code. This
3614 happens usually with "bottom boot sector" or "top boot
3615 sector" type flash chips, which have several smaller
3616 sectors at the start or the end. For instance, such a
3617 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3618 such a case you would place the environment in one of the
3619 4 kB sectors - with U-Boot code before and after it. With
3620 "top boot sector" type flash chips, you would put the
3621 environment in one of the last sectors, leaving a gap
3622 between U-Boot and the environment.
3624 - CONFIG_ENV_OFFSET:
3626 Offset of environment data (variable area) to the
3627 beginning of flash memory; for instance, with bottom boot
3628 type flash chips the second sector can be used: the offset
3629 for this sector is given here.
3631 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3635 This is just another way to specify the start address of
3636 the flash sector containing the environment (instead of
3639 - CONFIG_ENV_SECT_SIZE:
3641 Size of the sector containing the environment.
3644 b) Sometimes flash chips have few, equal sized, BIG sectors.
3645 In such a case you don't want to spend a whole sector for
3650 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3651 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3652 of this flash sector for the environment. This saves
3653 memory for the RAM copy of the environment.
3655 It may also save flash memory if you decide to use this
3656 when your environment is "embedded" within U-Boot code,
3657 since then the remainder of the flash sector could be used
3658 for U-Boot code. It should be pointed out that this is
3659 STRONGLY DISCOURAGED from a robustness point of view:
3660 updating the environment in flash makes it always
3661 necessary to erase the WHOLE sector. If something goes
3662 wrong before the contents has been restored from a copy in
3663 RAM, your target system will be dead.
3665 - CONFIG_ENV_ADDR_REDUND
3666 CONFIG_ENV_SIZE_REDUND
3668 These settings describe a second storage area used to hold
3669 a redundant copy of the environment data, so that there is
3670 a valid backup copy in case there is a power failure during
3671 a "saveenv" operation.
3673 BE CAREFUL! Any changes to the flash layout, and some changes to the
3674 source code will make it necessary to adapt <board>/u-boot.lds*
3678 - CONFIG_ENV_IS_IN_NVRAM:
3680 Define this if you have some non-volatile memory device
3681 (NVRAM, battery buffered SRAM) which you want to use for the
3687 These two #defines are used to determine the memory area you
3688 want to use for environment. It is assumed that this memory
3689 can just be read and written to, without any special
3692 BE CAREFUL! The first access to the environment happens quite early
3693 in U-Boot initalization (when we try to get the setting of for the
3694 console baudrate). You *MUST* have mapped your NVRAM area then, or
3697 Please note that even with NVRAM we still use a copy of the
3698 environment in RAM: we could work on NVRAM directly, but we want to
3699 keep settings there always unmodified except somebody uses "saveenv"
3700 to save the current settings.
3703 - CONFIG_ENV_IS_IN_EEPROM:
3705 Use this if you have an EEPROM or similar serial access
3706 device and a driver for it.
3708 - CONFIG_ENV_OFFSET:
3711 These two #defines specify the offset and size of the
3712 environment area within the total memory of your EEPROM.
3714 - CONFIG_SYS_I2C_EEPROM_ADDR:
3715 If defined, specified the chip address of the EEPROM device.
3716 The default address is zero.
3718 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3719 If defined, the number of bits used to address bytes in a
3720 single page in the EEPROM device. A 64 byte page, for example
3721 would require six bits.
3723 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3724 If defined, the number of milliseconds to delay between
3725 page writes. The default is zero milliseconds.
3727 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3728 The length in bytes of the EEPROM memory array address. Note
3729 that this is NOT the chip address length!
3731 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3732 EEPROM chips that implement "address overflow" are ones
3733 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3734 address and the extra bits end up in the "chip address" bit
3735 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3738 Note that we consider the length of the address field to
3739 still be one byte because the extra address bits are hidden
3740 in the chip address.
3742 - CONFIG_SYS_EEPROM_SIZE:
3743 The size in bytes of the EEPROM device.
3745 - CONFIG_ENV_EEPROM_IS_ON_I2C
3746 define this, if you have I2C and SPI activated, and your
3747 EEPROM, which holds the environment, is on the I2C bus.
3749 - CONFIG_I2C_ENV_EEPROM_BUS
3750 if you have an Environment on an EEPROM reached over
3751 I2C muxes, you can define here, how to reach this
3752 EEPROM. For example:
3754 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3756 EEPROM which holds the environment, is reached over
3757 a pca9547 i2c mux with address 0x70, channel 3.
3759 - CONFIG_ENV_IS_IN_DATAFLASH:
3761 Define this if you have a DataFlash memory device which you
3762 want to use for the environment.
3764 - CONFIG_ENV_OFFSET:
3768 These three #defines specify the offset and size of the
3769 environment area within the total memory of your DataFlash placed
3770 at the specified address.
3772 - CONFIG_ENV_IS_IN_REMOTE:
3774 Define this if you have a remote memory space which you
3775 want to use for the local device's environment.
3780 These two #defines specify the address and size of the
3781 environment area within the remote memory space. The
3782 local device can get the environment from remote memory
3783 space by SRIO or PCIE links.
3785 BE CAREFUL! For some special cases, the local device can not use
3786 "saveenv" command. For example, the local device will get the
3787 environment stored in a remote NOR flash by SRIO or PCIE link,
3788 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3790 - CONFIG_ENV_IS_IN_NAND:
3792 Define this if you have a NAND device which you want to use
3793 for the environment.
3795 - CONFIG_ENV_OFFSET:
3798 These two #defines specify the offset and size of the environment
3799 area within the first NAND device. CONFIG_ENV_OFFSET must be
3800 aligned to an erase block boundary.
3802 - CONFIG_ENV_OFFSET_REDUND (optional):
3804 This setting describes a second storage area of CONFIG_ENV_SIZE
3805 size used to hold a redundant copy of the environment data, so
3806 that there is a valid backup copy in case there is a power failure
3807 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3808 aligned to an erase block boundary.
3810 - CONFIG_ENV_RANGE (optional):
3812 Specifies the length of the region in which the environment
3813 can be written. This should be a multiple of the NAND device's
3814 block size. Specifying a range with more erase blocks than
3815 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3816 the range to be avoided.
3818 - CONFIG_ENV_OFFSET_OOB (optional):
3820 Enables support for dynamically retrieving the offset of the
3821 environment from block zero's out-of-band data. The
3822 "nand env.oob" command can be used to record this offset.
3823 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3824 using CONFIG_ENV_OFFSET_OOB.
3826 - CONFIG_NAND_ENV_DST
3828 Defines address in RAM to which the nand_spl code should copy the
3829 environment. If redundant environment is used, it will be copied to
3830 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3832 - CONFIG_ENV_IS_IN_UBI:
3834 Define this if you have an UBI volume that you want to use for the
3835 environment. This has the benefit of wear-leveling the environment
3836 accesses, which is important on NAND.
3838 - CONFIG_ENV_UBI_PART:
3840 Define this to a string that is the mtd partition containing the UBI.
3842 - CONFIG_ENV_UBI_VOLUME:
3844 Define this to the name of the volume that you want to store the
3847 - CONFIG_ENV_UBI_VOLUME_REDUND:
3849 Define this to the name of another volume to store a second copy of
3850 the environment in. This will enable redundant environments in UBI.
3851 It is assumed that both volumes are in the same MTD partition.
3853 - CONFIG_UBI_SILENCE_MSG
3854 - CONFIG_UBIFS_SILENCE_MSG
3856 You will probably want to define these to avoid a really noisy system
3857 when storing the env in UBI.
3859 - CONFIG_ENV_IS_IN_MMC:
3861 Define this if you have an MMC device which you want to use for the
3864 - CONFIG_SYS_MMC_ENV_DEV:
3866 Specifies which MMC device the environment is stored in.
3868 - CONFIG_SYS_MMC_ENV_PART (optional):
3870 Specifies which MMC partition the environment is stored in. If not
3871 set, defaults to partition 0, the user area. Common values might be
3872 1 (first MMC boot partition), 2 (second MMC boot partition).
3874 - CONFIG_ENV_OFFSET:
3877 These two #defines specify the offset and size of the environment
3878 area within the specified MMC device.
3880 If offset is positive (the usual case), it is treated as relative to
3881 the start of the MMC partition. If offset is negative, it is treated
3882 as relative to the end of the MMC partition. This can be useful if
3883 your board may be fitted with different MMC devices, which have
3884 different sizes for the MMC partitions, and you always want the
3885 environment placed at the very end of the partition, to leave the
3886 maximum possible space before it, to store other data.
3888 These two values are in units of bytes, but must be aligned to an
3889 MMC sector boundary.
3891 - CONFIG_ENV_OFFSET_REDUND (optional):
3893 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3894 hold a redundant copy of the environment data. This provides a
3895 valid backup copy in case the other copy is corrupted, e.g. due
3896 to a power failure during a "saveenv" operation.
3898 This value may also be positive or negative; this is handled in the
3899 same way as CONFIG_ENV_OFFSET.
3901 This value is also in units of bytes, but must also be aligned to
3902 an MMC sector boundary.
3904 - CONFIG_ENV_SIZE_REDUND (optional):
3906 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3907 set. If this value is set, it must be set to the same value as
3910 - CONFIG_SYS_SPI_INIT_OFFSET
3912 Defines offset to the initial SPI buffer area in DPRAM. The
3913 area is used at an early stage (ROM part) if the environment
3914 is configured to reside in the SPI EEPROM: We need a 520 byte
3915 scratch DPRAM area. It is used between the two initialization
3916 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3917 to be a good choice since it makes it far enough from the
3918 start of the data area as well as from the stack pointer.
3920 Please note that the environment is read-only until the monitor
3921 has been relocated to RAM and a RAM copy of the environment has been
3922 created; also, when using EEPROM you will have to use getenv_f()
3923 until then to read environment variables.
3925 The environment is protected by a CRC32 checksum. Before the monitor
3926 is relocated into RAM, as a result of a bad CRC you will be working
3927 with the compiled-in default environment - *silently*!!! [This is
3928 necessary, because the first environment variable we need is the
3929 "baudrate" setting for the console - if we have a bad CRC, we don't
3930 have any device yet where we could complain.]
3932 Note: once the monitor has been relocated, then it will complain if
3933 the default environment is used; a new CRC is computed as soon as you
3934 use the "saveenv" command to store a valid environment.
3936 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3937 Echo the inverted Ethernet link state to the fault LED.
3939 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3940 also needs to be defined.
3942 - CONFIG_SYS_FAULT_MII_ADDR:
3943 MII address of the PHY to check for the Ethernet link state.
3945 - CONFIG_NS16550_MIN_FUNCTIONS:
3946 Define this if you desire to only have use of the NS16550_init
3947 and NS16550_putc functions for the serial driver located at
3948 drivers/serial/ns16550.c. This option is useful for saving
3949 space for already greatly restricted images, including but not
3950 limited to NAND_SPL configurations.
3952 - CONFIG_DISPLAY_BOARDINFO
3953 Display information about the board that U-Boot is running on
3954 when U-Boot starts up. The board function checkboard() is called
3957 - CONFIG_DISPLAY_BOARDINFO_LATE
3958 Similar to the previous option, but display this information
3959 later, once stdio is running and output goes to the LCD, if
3962 Low Level (hardware related) configuration options:
3963 ---------------------------------------------------
3965 - CONFIG_SYS_CACHELINE_SIZE:
3966 Cache Line Size of the CPU.
3968 - CONFIG_SYS_DEFAULT_IMMR:
3969 Default address of the IMMR after system reset.
3971 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3972 and RPXsuper) to be able to adjust the position of
3973 the IMMR register after a reset.
3975 - CONFIG_SYS_CCSRBAR_DEFAULT:
3976 Default (power-on reset) physical address of CCSR on Freescale
3979 - CONFIG_SYS_CCSRBAR:
3980 Virtual address of CCSR. On a 32-bit build, this is typically
3981 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3983 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3984 for cross-platform code that uses that macro instead.
3986 - CONFIG_SYS_CCSRBAR_PHYS:
3987 Physical address of CCSR. CCSR can be relocated to a new
3988 physical address, if desired. In this case, this macro should
3989 be set to that address. Otherwise, it should be set to the
3990 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3991 is typically relocated on 36-bit builds. It is recommended
3992 that this macro be defined via the _HIGH and _LOW macros:
3994 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3995 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3997 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3998 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3999 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4000 used in assembly code, so it must not contain typecasts or
4001 integer size suffixes (e.g. "ULL").
4003 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4004 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4005 used in assembly code, so it must not contain typecasts or
4006 integer size suffixes (e.g. "ULL").
4008 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4009 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4010 forced to a value that ensures that CCSR is not relocated.
4012 - Floppy Disk Support:
4013 CONFIG_SYS_FDC_DRIVE_NUMBER
4015 the default drive number (default value 0)
4017 CONFIG_SYS_ISA_IO_STRIDE
4019 defines the spacing between FDC chipset registers
4022 CONFIG_SYS_ISA_IO_OFFSET
4024 defines the offset of register from address. It
4025 depends on which part of the data bus is connected to
4026 the FDC chipset. (default value 0)
4028 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4029 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4032 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4033 fdc_hw_init() is called at the beginning of the FDC
4034 setup. fdc_hw_init() must be provided by the board
4035 source code. It is used to make hardware dependant
4039 Most IDE controllers were designed to be connected with PCI
4040 interface. Only few of them were designed for AHB interface.
4041 When software is doing ATA command and data transfer to
4042 IDE devices through IDE-AHB controller, some additional
4043 registers accessing to these kind of IDE-AHB controller
4046 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4047 DO NOT CHANGE unless you know exactly what you're
4048 doing! (11-4) [MPC8xx/82xx systems only]
4050 - CONFIG_SYS_INIT_RAM_ADDR:
4052 Start address of memory area that can be used for
4053 initial data and stack; please note that this must be
4054 writable memory that is working WITHOUT special
4055 initialization, i. e. you CANNOT use normal RAM which
4056 will become available only after programming the
4057 memory controller and running certain initialization
4060 U-Boot uses the following memory types:
4061 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4062 - MPC824X: data cache
4063 - PPC4xx: data cache
4065 - CONFIG_SYS_GBL_DATA_OFFSET:
4067 Offset of the initial data structure in the memory
4068 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4069 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4070 data is located at the end of the available space
4071 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4072 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4073 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4074 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4077 On the MPC824X (or other systems that use the data
4078 cache for initial memory) the address chosen for
4079 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4080 point to an otherwise UNUSED address space between
4081 the top of RAM and the start of the PCI space.
4083 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4085 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4087 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4089 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4091 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4093 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4095 - CONFIG_SYS_OR_TIMING_SDRAM:
4098 - CONFIG_SYS_MAMR_PTA:
4099 periodic timer for refresh
4101 - CONFIG_SYS_DER: Debug Event Register (37-47)
4103 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4104 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4105 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4106 CONFIG_SYS_BR1_PRELIM:
4107 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4109 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4110 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4111 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4112 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4114 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4115 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4116 Machine Mode Register and Memory Periodic Timer
4117 Prescaler definitions (SDRAM timing)
4119 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4120 enable I2C microcode relocation patch (MPC8xx);
4121 define relocation offset in DPRAM [DSP2]
4123 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4124 enable SMC microcode relocation patch (MPC8xx);
4125 define relocation offset in DPRAM [SMC1]
4127 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4128 enable SPI microcode relocation patch (MPC8xx);
4129 define relocation offset in DPRAM [SCC4]
4131 - CONFIG_SYS_USE_OSCCLK:
4132 Use OSCM clock mode on MBX8xx board. Be careful,
4133 wrong setting might damage your board. Read
4134 doc/README.MBX before setting this variable!
4136 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4137 Offset of the bootmode word in DPRAM used by post
4138 (Power On Self Tests). This definition overrides
4139 #define'd default value in commproc.h resp.
4142 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4143 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4144 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4145 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4146 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4147 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4148 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4149 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4150 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4152 - CONFIG_PCI_DISABLE_PCIE:
4153 Disable PCI-Express on systems where it is supported but not
4156 - CONFIG_PCI_ENUM_ONLY
4157 Only scan through and get the devices on the busses.
4158 Don't do any setup work, presumably because someone or
4159 something has already done it, and we don't need to do it
4160 a second time. Useful for platforms that are pre-booted
4161 by coreboot or similar.
4163 - CONFIG_PCI_INDIRECT_BRIDGE:
4164 Enable support for indirect PCI bridges.
4167 Chip has SRIO or not
4170 Board has SRIO 1 port available
4173 Board has SRIO 2 port available
4175 - CONFIG_SRIO_PCIE_BOOT_MASTER
4176 Board can support master function for Boot from SRIO and PCIE
4178 - CONFIG_SYS_SRIOn_MEM_VIRT:
4179 Virtual Address of SRIO port 'n' memory region
4181 - CONFIG_SYS_SRIOn_MEM_PHYS:
4182 Physical Address of SRIO port 'n' memory region
4184 - CONFIG_SYS_SRIOn_MEM_SIZE:
4185 Size of SRIO port 'n' memory region
4187 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4188 Defined to tell the NAND controller that the NAND chip is using
4190 Not all NAND drivers use this symbol.
4191 Example of drivers that use it:
4192 - drivers/mtd/nand/ndfc.c
4193 - drivers/mtd/nand/mxc_nand.c
4195 - CONFIG_SYS_NDFC_EBC0_CFG
4196 Sets the EBC0_CFG register for the NDFC. If not defined
4197 a default value will be used.
4200 Get DDR timing information from an I2C EEPROM. Common
4201 with pluggable memory modules such as SODIMMs
4204 I2C address of the SPD EEPROM
4206 - CONFIG_SYS_SPD_BUS_NUM
4207 If SPD EEPROM is on an I2C bus other than the first
4208 one, specify here. Note that the value must resolve
4209 to something your driver can deal with.
4211 - CONFIG_SYS_DDR_RAW_TIMING
4212 Get DDR timing information from other than SPD. Common with
4213 soldered DDR chips onboard without SPD. DDR raw timing
4214 parameters are extracted from datasheet and hard-coded into
4215 header files or board specific files.
4217 - CONFIG_FSL_DDR_INTERACTIVE
4218 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4220 - CONFIG_SYS_83XX_DDR_USES_CS0
4221 Only for 83xx systems. If specified, then DDR should
4222 be configured using CS0 and CS1 instead of CS2 and CS3.
4224 - CONFIG_ETHER_ON_FEC[12]
4225 Define to enable FEC[12] on a 8xx series processor.
4227 - CONFIG_FEC[12]_PHY
4228 Define to the hardcoded PHY address which corresponds
4229 to the given FEC; i. e.
4230 #define CONFIG_FEC1_PHY 4
4231 means that the PHY with address 4 is connected to FEC1
4233 When set to -1, means to probe for first available.
4235 - CONFIG_FEC[12]_PHY_NORXERR
4236 The PHY does not have a RXERR line (RMII only).
4237 (so program the FEC to ignore it).
4240 Enable RMII mode for all FECs.
4241 Note that this is a global option, we can't
4242 have one FEC in standard MII mode and another in RMII mode.
4244 - CONFIG_CRC32_VERIFY
4245 Add a verify option to the crc32 command.
4248 => crc32 -v <address> <count> <crc32>
4250 Where address/count indicate a memory area
4251 and crc32 is the correct crc32 which the
4255 Add the "loopw" memory command. This only takes effect if
4256 the memory commands are activated globally (CONFIG_CMD_MEM).
4259 Add the "mdc" and "mwc" memory commands. These are cyclic
4264 This command will print 4 bytes (10,11,12,13) each 500 ms.
4266 => mwc.l 100 12345678 10
4267 This command will write 12345678 to address 100 all 10 ms.
4269 This only takes effect if the memory commands are activated
4270 globally (CONFIG_CMD_MEM).
4272 - CONFIG_SKIP_LOWLEVEL_INIT
4273 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4274 low level initializations (like setting up the memory
4275 controller) are omitted and/or U-Boot does not
4276 relocate itself into RAM.
4278 Normally this variable MUST NOT be defined. The only
4279 exception is when U-Boot is loaded (to RAM) by some
4280 other boot loader or by a debugger which performs
4281 these initializations itself.
4284 Modifies the behaviour of start.S when compiling a loader
4285 that is executed before the actual U-Boot. E.g. when
4286 compiling a NAND SPL.
4289 Modifies the behaviour of start.S when compiling a loader
4290 that is executed after the SPL and before the actual U-Boot.
4291 It is loaded by the SPL.
4293 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4294 Only for 85xx systems. If this variable is specified, the section
4295 .resetvec is not kept and the section .bootpg is placed in the
4296 previous 4k of the .text section.
4298 - CONFIG_ARCH_MAP_SYSMEM
4299 Generally U-Boot (and in particular the md command) uses
4300 effective address. It is therefore not necessary to regard
4301 U-Boot address as virtual addresses that need to be translated
4302 to physical addresses. However, sandbox requires this, since
4303 it maintains its own little RAM buffer which contains all
4304 addressable memory. This option causes some memory accesses
4305 to be mapped through map_sysmem() / unmap_sysmem().
4307 - CONFIG_USE_ARCH_MEMCPY
4308 CONFIG_USE_ARCH_MEMSET
4309 If these options are used a optimized version of memcpy/memset will
4310 be used if available. These functions may be faster under some
4311 conditions but may increase the binary size.
4313 - CONFIG_X86_RESET_VECTOR
4314 If defined, the x86 reset vector code is included. This is not
4315 needed when U-Boot is running from Coreboot.
4318 Defines the MPU clock speed (in MHz).
4320 NOTE : currently only supported on AM335x platforms.
4322 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4323 Enables the RTC32K OSC on AM33xx based plattforms
4325 Freescale QE/FMAN Firmware Support:
4326 -----------------------------------
4328 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4329 loading of "firmware", which is encoded in the QE firmware binary format.
4330 This firmware often needs to be loaded during U-Boot booting, so macros
4331 are used to identify the storage device (NOR flash, SPI, etc) and the address
4334 - CONFIG_SYS_QE_FMAN_FW_ADDR
4335 The address in the storage device where the firmware is located. The
4336 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4339 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4340 The maximum possible size of the firmware. The firmware binary format
4341 has a field that specifies the actual size of the firmware, but it
4342 might not be possible to read any part of the firmware unless some
4343 local storage is allocated to hold the entire firmware first.
4345 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4346 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4347 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4348 virtual address in NOR flash.
4350 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4351 Specifies that QE/FMAN firmware is located in NAND flash.
4352 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4354 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4355 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4356 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4358 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4359 Specifies that QE/FMAN firmware is located on the primary SPI
4360 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4362 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4363 Specifies that QE/FMAN firmware is located in the remote (master)
4364 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4365 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4366 window->master inbound window->master LAW->the ucode address in
4367 master's memory space.
4369 Building the Software:
4370 ======================
4372 Building U-Boot has been tested in several native build environments
4373 and in many different cross environments. Of course we cannot support
4374 all possibly existing versions of cross development tools in all
4375 (potentially obsolete) versions. In case of tool chain problems we
4376 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4377 which is extensively used to build and test U-Boot.
4379 If you are not using a native environment, it is assumed that you
4380 have GNU cross compiling tools available in your path. In this case,
4381 you must set the environment variable CROSS_COMPILE in your shell.
4382 Note that no changes to the Makefile or any other source files are
4383 necessary. For example using the ELDK on a 4xx CPU, please enter:
4385 $ CROSS_COMPILE=ppc_4xx-
4386 $ export CROSS_COMPILE
4388 Note: If you wish to generate Windows versions of the utilities in
4389 the tools directory you can use the MinGW toolchain
4390 (http://www.mingw.org). Set your HOST tools to the MinGW
4391 toolchain and execute 'make tools'. For example:
4393 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4395 Binaries such as tools/mkimage.exe will be created which can
4396 be executed on computers running Windows.
4398 U-Boot is intended to be simple to build. After installing the
4399 sources you must configure U-Boot for one specific board type. This
4404 where "NAME_config" is the name of one of the existing configu-
4405 rations; see boards.cfg for supported names.
4407 Note: for some board special configuration names may exist; check if
4408 additional information is available from the board vendor; for
4409 instance, the TQM823L systems are available without (standard)
4410 or with LCD support. You can select such additional "features"
4411 when choosing the configuration, i. e.
4414 - will configure for a plain TQM823L, i. e. no LCD support
4416 make TQM823L_LCD_config
4417 - will configure for a TQM823L with U-Boot console on LCD
4422 Finally, type "make all", and you should get some working U-Boot
4423 images ready for download to / installation on your system:
4425 - "u-boot.bin" is a raw binary image
4426 - "u-boot" is an image in ELF binary format
4427 - "u-boot.srec" is in Motorola S-Record format
4429 By default the build is performed locally and the objects are saved
4430 in the source directory. One of the two methods can be used to change
4431 this behavior and build U-Boot to some external directory:
4433 1. Add O= to the make command line invocations:
4435 make O=/tmp/build distclean
4436 make O=/tmp/build NAME_config
4437 make O=/tmp/build all
4439 2. Set environment variable BUILD_DIR to point to the desired location:
4441 export BUILD_DIR=/tmp/build
4446 Note that the command line "O=" setting overrides the BUILD_DIR environment
4450 Please be aware that the Makefiles assume you are using GNU make, so
4451 for instance on NetBSD you might need to use "gmake" instead of
4455 If the system board that you have is not listed, then you will need
4456 to port U-Boot to your hardware platform. To do this, follow these
4459 1. Add a new configuration option for your board to the toplevel
4460 "boards.cfg" file, using the existing entries as examples.
4461 Follow the instructions there to keep the boards in order.
4462 2. Create a new directory to hold your board specific code. Add any
4463 files you need. In your board directory, you will need at least
4464 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4465 3. Create a new configuration file "include/configs/<board>.h" for
4467 3. If you're porting U-Boot to a new CPU, then also create a new
4468 directory to hold your CPU specific code. Add any files you need.
4469 4. Run "make <board>_config" with your new name.
4470 5. Type "make", and you should get a working "u-boot.srec" file
4471 to be installed on your target system.
4472 6. Debug and solve any problems that might arise.
4473 [Of course, this last step is much harder than it sounds.]
4476 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4477 ==============================================================
4479 If you have modified U-Boot sources (for instance added a new board
4480 or support for new devices, a new CPU, etc.) you are expected to
4481 provide feedback to the other developers. The feedback normally takes
4482 the form of a "patch", i. e. a context diff against a certain (latest
4483 official or latest in the git repository) version of U-Boot sources.
4485 But before you submit such a patch, please verify that your modifi-
4486 cation did not break existing code. At least make sure that *ALL* of
4487 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4488 just run the "MAKEALL" script, which will configure and build U-Boot
4489 for ALL supported system. Be warned, this will take a while. You can
4490 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4491 environment variable to the script, i. e. to use the ELDK cross tools
4494 CROSS_COMPILE=ppc_8xx- MAKEALL
4496 or to build on a native PowerPC system you can type
4498 CROSS_COMPILE=' ' MAKEALL
4500 When using the MAKEALL script, the default behaviour is to build
4501 U-Boot in the source directory. This location can be changed by
4502 setting the BUILD_DIR environment variable. Also, for each target
4503 built, the MAKEALL script saves two log files (<target>.ERR and
4504 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4505 location can be changed by setting the MAKEALL_LOGDIR environment
4506 variable. For example:
4508 export BUILD_DIR=/tmp/build
4509 export MAKEALL_LOGDIR=/tmp/log
4510 CROSS_COMPILE=ppc_8xx- MAKEALL
4512 With the above settings build objects are saved in the /tmp/build,
4513 log files are saved in the /tmp/log and the source tree remains clean
4514 during the whole build process.
4517 See also "U-Boot Porting Guide" below.
4520 Monitor Commands - Overview:
4521 ============================
4523 go - start application at address 'addr'
4524 run - run commands in an environment variable
4525 bootm - boot application image from memory
4526 bootp - boot image via network using BootP/TFTP protocol
4527 bootz - boot zImage from memory
4528 tftpboot- boot image via network using TFTP protocol
4529 and env variables "ipaddr" and "serverip"
4530 (and eventually "gatewayip")
4531 tftpput - upload a file via network using TFTP protocol
4532 rarpboot- boot image via network using RARP/TFTP protocol
4533 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4534 loads - load S-Record file over serial line
4535 loadb - load binary file over serial line (kermit mode)
4537 mm - memory modify (auto-incrementing)
4538 nm - memory modify (constant address)
4539 mw - memory write (fill)
4541 cmp - memory compare
4542 crc32 - checksum calculation
4543 i2c - I2C sub-system
4544 sspi - SPI utility commands
4545 base - print or set address offset
4546 printenv- print environment variables
4547 setenv - set environment variables
4548 saveenv - save environment variables to persistent storage
4549 protect - enable or disable FLASH write protection
4550 erase - erase FLASH memory
4551 flinfo - print FLASH memory information
4552 nand - NAND memory operations (see doc/README.nand)
4553 bdinfo - print Board Info structure
4554 iminfo - print header information for application image
4555 coninfo - print console devices and informations
4556 ide - IDE sub-system
4557 loop - infinite loop on address range
4558 loopw - infinite write loop on address range
4559 mtest - simple RAM test
4560 icache - enable or disable instruction cache
4561 dcache - enable or disable data cache
4562 reset - Perform RESET of the CPU
4563 echo - echo args to console
4564 version - print monitor version
4565 help - print online help
4566 ? - alias for 'help'
4569 Monitor Commands - Detailed Description:
4570 ========================================
4574 For now: just type "help <command>".
4577 Environment Variables:
4578 ======================
4580 U-Boot supports user configuration using Environment Variables which
4581 can be made persistent by saving to Flash memory.
4583 Environment Variables are set using "setenv", printed using
4584 "printenv", and saved to Flash using "saveenv". Using "setenv"
4585 without a value can be used to delete a variable from the
4586 environment. As long as you don't save the environment you are
4587 working with an in-memory copy. In case the Flash area containing the
4588 environment is erased by accident, a default environment is provided.
4590 Some configuration options can be set using Environment Variables.
4592 List of environment variables (most likely not complete):
4594 baudrate - see CONFIG_BAUDRATE
4596 bootdelay - see CONFIG_BOOTDELAY
4598 bootcmd - see CONFIG_BOOTCOMMAND
4600 bootargs - Boot arguments when booting an RTOS image
4602 bootfile - Name of the image to load with TFTP
4604 bootm_low - Memory range available for image processing in the bootm
4605 command can be restricted. This variable is given as
4606 a hexadecimal number and defines lowest address allowed
4607 for use by the bootm command. See also "bootm_size"
4608 environment variable. Address defined by "bootm_low" is
4609 also the base of the initial memory mapping for the Linux
4610 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4613 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4614 This variable is given as a hexadecimal number and it
4615 defines the size of the memory region starting at base
4616 address bootm_low that is accessible by the Linux kernel
4617 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4618 as the default value if it is defined, and bootm_size is
4621 bootm_size - Memory range available for image processing in the bootm
4622 command can be restricted. This variable is given as
4623 a hexadecimal number and defines the size of the region
4624 allowed for use by the bootm command. See also "bootm_low"
4625 environment variable.
4627 updatefile - Location of the software update file on a TFTP server, used
4628 by the automatic software update feature. Please refer to
4629 documentation in doc/README.update for more details.
4631 autoload - if set to "no" (any string beginning with 'n'),
4632 "bootp" will just load perform a lookup of the
4633 configuration from the BOOTP server, but not try to
4634 load any image using TFTP
4636 autostart - if set to "yes", an image loaded using the "bootp",
4637 "rarpboot", "tftpboot" or "diskboot" commands will
4638 be automatically started (by internally calling
4641 If set to "no", a standalone image passed to the
4642 "bootm" command will be copied to the load address
4643 (and eventually uncompressed), but NOT be started.
4644 This can be used to load and uncompress arbitrary
4647 fdt_high - if set this restricts the maximum address that the
4648 flattened device tree will be copied into upon boot.
4649 For example, if you have a system with 1 GB memory
4650 at physical address 0x10000000, while Linux kernel
4651 only recognizes the first 704 MB as low memory, you
4652 may need to set fdt_high as 0x3C000000 to have the
4653 device tree blob be copied to the maximum address
4654 of the 704 MB low memory, so that Linux kernel can
4655 access it during the boot procedure.
4657 If this is set to the special value 0xFFFFFFFF then
4658 the fdt will not be copied at all on boot. For this
4659 to work it must reside in writable memory, have
4660 sufficient padding on the end of it for u-boot to
4661 add the information it needs into it, and the memory
4662 must be accessible by the kernel.
4664 fdtcontroladdr- if set this is the address of the control flattened
4665 device tree used by U-Boot when CONFIG_OF_CONTROL is
4668 i2cfast - (PPC405GP|PPC405EP only)
4669 if set to 'y' configures Linux I2C driver for fast
4670 mode (400kHZ). This environment variable is used in
4671 initialization code. So, for changes to be effective
4672 it must be saved and board must be reset.
4674 initrd_high - restrict positioning of initrd images:
4675 If this variable is not set, initrd images will be
4676 copied to the highest possible address in RAM; this
4677 is usually what you want since it allows for
4678 maximum initrd size. If for some reason you want to
4679 make sure that the initrd image is loaded below the
4680 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4681 variable to a value of "no" or "off" or "0".
4682 Alternatively, you can set it to a maximum upper
4683 address to use (U-Boot will still check that it
4684 does not overwrite the U-Boot stack and data).
4686 For instance, when you have a system with 16 MB
4687 RAM, and want to reserve 4 MB from use by Linux,
4688 you can do this by adding "mem=12M" to the value of
4689 the "bootargs" variable. However, now you must make
4690 sure that the initrd image is placed in the first
4691 12 MB as well - this can be done with
4693 setenv initrd_high 00c00000
4695 If you set initrd_high to 0xFFFFFFFF, this is an
4696 indication to U-Boot that all addresses are legal
4697 for the Linux kernel, including addresses in flash
4698 memory. In this case U-Boot will NOT COPY the
4699 ramdisk at all. This may be useful to reduce the
4700 boot time on your system, but requires that this
4701 feature is supported by your Linux kernel.
4703 ipaddr - IP address; needed for tftpboot command
4705 loadaddr - Default load address for commands like "bootp",
4706 "rarpboot", "tftpboot", "loadb" or "diskboot"
4708 loads_echo - see CONFIG_LOADS_ECHO
4710 serverip - TFTP server IP address; needed for tftpboot command
4712 bootretry - see CONFIG_BOOT_RETRY_TIME
4714 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4716 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4718 ethprime - controls which interface is used first.
4720 ethact - controls which interface is currently active.
4721 For example you can do the following
4723 => setenv ethact FEC
4724 => ping 192.168.0.1 # traffic sent on FEC
4725 => setenv ethact SCC
4726 => ping 10.0.0.1 # traffic sent on SCC
4728 ethrotate - When set to "no" U-Boot does not go through all
4729 available network interfaces.
4730 It just stays at the currently selected interface.
4732 netretry - When set to "no" each network operation will
4733 either succeed or fail without retrying.
4734 When set to "once" the network operation will
4735 fail when all the available network interfaces
4736 are tried once without success.
4737 Useful on scripts which control the retry operation
4740 npe_ucode - set load address for the NPE microcode
4742 silent_linux - If set then linux will be told to boot silently, by
4743 changing the console to be empty. If "yes" it will be
4744 made silent. If "no" it will not be made silent. If
4745 unset, then it will be made silent if the U-Boot console
4748 tftpsrcport - If this is set, the value is used for TFTP's
4751 tftpdstport - If this is set, the value is used for TFTP's UDP
4752 destination port instead of the Well Know Port 69.
4754 tftpblocksize - Block size to use for TFTP transfers; if not set,
4755 we use the TFTP server's default block size
4757 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4758 seconds, minimum value is 1000 = 1 second). Defines
4759 when a packet is considered to be lost so it has to
4760 be retransmitted. The default is 5000 = 5 seconds.
4761 Lowering this value may make downloads succeed
4762 faster in networks with high packet loss rates or
4763 with unreliable TFTP servers.
4765 vlan - When set to a value < 4095 the traffic over
4766 Ethernet is encapsulated/received over 802.1q
4769 The following image location variables contain the location of images
4770 used in booting. The "Image" column gives the role of the image and is
4771 not an environment variable name. The other columns are environment
4772 variable names. "File Name" gives the name of the file on a TFTP
4773 server, "RAM Address" gives the location in RAM the image will be
4774 loaded to, and "Flash Location" gives the image's address in NOR
4775 flash or offset in NAND flash.
4777 *Note* - these variables don't have to be defined for all boards, some
4778 boards currenlty use other variables for these purposes, and some
4779 boards use these variables for other purposes.
4781 Image File Name RAM Address Flash Location
4782 ----- --------- ----------- --------------
4783 u-boot u-boot u-boot_addr_r u-boot_addr
4784 Linux kernel bootfile kernel_addr_r kernel_addr
4785 device tree blob fdtfile fdt_addr_r fdt_addr
4786 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4788 The following environment variables may be used and automatically
4789 updated by the network boot commands ("bootp" and "rarpboot"),
4790 depending the information provided by your boot server:
4792 bootfile - see above
4793 dnsip - IP address of your Domain Name Server
4794 dnsip2 - IP address of your secondary Domain Name Server
4795 gatewayip - IP address of the Gateway (Router) to use
4796 hostname - Target hostname
4798 netmask - Subnet Mask
4799 rootpath - Pathname of the root filesystem on the NFS server
4800 serverip - see above
4803 There are two special Environment Variables:
4805 serial# - contains hardware identification information such
4806 as type string and/or serial number
4807 ethaddr - Ethernet address
4809 These variables can be set only once (usually during manufacturing of
4810 the board). U-Boot refuses to delete or overwrite these variables
4811 once they have been set once.
4814 Further special Environment Variables:
4816 ver - Contains the U-Boot version string as printed
4817 with the "version" command. This variable is
4818 readonly (see CONFIG_VERSION_VARIABLE).
4821 Please note that changes to some configuration parameters may take
4822 only effect after the next boot (yes, that's just like Windoze :-).
4825 Callback functions for environment variables:
4826 ---------------------------------------------
4828 For some environment variables, the behavior of u-boot needs to change
4829 when their values are changed. This functionailty allows functions to
4830 be associated with arbitrary variables. On creation, overwrite, or
4831 deletion, the callback will provide the opportunity for some side
4832 effect to happen or for the change to be rejected.
4834 The callbacks are named and associated with a function using the
4835 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4837 These callbacks are associated with variables in one of two ways. The
4838 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4839 in the board configuration to a string that defines a list of
4840 associations. The list must be in the following format:
4842 entry = variable_name[:callback_name]
4845 If the callback name is not specified, then the callback is deleted.
4846 Spaces are also allowed anywhere in the list.
4848 Callbacks can also be associated by defining the ".callbacks" variable
4849 with the same list format above. Any association in ".callbacks" will
4850 override any association in the static list. You can define
4851 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4852 ".callbacks" envirnoment variable in the default or embedded environment.
4855 Command Line Parsing:
4856 =====================
4858 There are two different command line parsers available with U-Boot:
4859 the old "simple" one, and the much more powerful "hush" shell:
4861 Old, simple command line parser:
4862 --------------------------------
4864 - supports environment variables (through setenv / saveenv commands)
4865 - several commands on one line, separated by ';'
4866 - variable substitution using "... ${name} ..." syntax
4867 - special characters ('$', ';') can be escaped by prefixing with '\',
4869 setenv bootcmd bootm \${address}
4870 - You can also escape text by enclosing in single apostrophes, for example:
4871 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4876 - similar to Bourne shell, with control structures like
4877 if...then...else...fi, for...do...done; while...do...done,
4878 until...do...done, ...
4879 - supports environment ("global") variables (through setenv / saveenv
4880 commands) and local shell variables (through standard shell syntax
4881 "name=value"); only environment variables can be used with "run"
4887 (1) If a command line (or an environment variable executed by a "run"
4888 command) contains several commands separated by semicolon, and
4889 one of these commands fails, then the remaining commands will be
4892 (2) If you execute several variables with one call to run (i. e.
4893 calling run with a list of variables as arguments), any failing
4894 command will cause "run" to terminate, i. e. the remaining
4895 variables are not executed.
4897 Note for Redundant Ethernet Interfaces:
4898 =======================================
4900 Some boards come with redundant Ethernet interfaces; U-Boot supports
4901 such configurations and is capable of automatic selection of a
4902 "working" interface when needed. MAC assignment works as follows:
4904 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4905 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4906 "eth1addr" (=>eth1), "eth2addr", ...
4908 If the network interface stores some valid MAC address (for instance
4909 in SROM), this is used as default address if there is NO correspon-
4910 ding setting in the environment; if the corresponding environment
4911 variable is set, this overrides the settings in the card; that means:
4913 o If the SROM has a valid MAC address, and there is no address in the
4914 environment, the SROM's address is used.
4916 o If there is no valid address in the SROM, and a definition in the
4917 environment exists, then the value from the environment variable is
4920 o If both the SROM and the environment contain a MAC address, and
4921 both addresses are the same, this MAC address is used.
4923 o If both the SROM and the environment contain a MAC address, and the
4924 addresses differ, the value from the environment is used and a
4927 o If neither SROM nor the environment contain a MAC address, an error
4930 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4931 will be programmed into hardware as part of the initialization process. This
4932 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4933 The naming convention is as follows:
4934 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4939 U-Boot is capable of booting (and performing other auxiliary operations on)
4940 images in two formats:
4942 New uImage format (FIT)
4943 -----------------------
4945 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4946 to Flattened Device Tree). It allows the use of images with multiple
4947 components (several kernels, ramdisks, etc.), with contents protected by
4948 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4954 Old image format is based on binary files which can be basically anything,
4955 preceded by a special header; see the definitions in include/image.h for
4956 details; basically, the header defines the following image properties:
4958 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4959 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4960 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4961 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4963 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4964 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4965 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4966 * Compression Type (uncompressed, gzip, bzip2)
4972 The header is marked by a special Magic Number, and both the header
4973 and the data portions of the image are secured against corruption by
4980 Although U-Boot should support any OS or standalone application
4981 easily, the main focus has always been on Linux during the design of
4984 U-Boot includes many features that so far have been part of some
4985 special "boot loader" code within the Linux kernel. Also, any
4986 "initrd" images to be used are no longer part of one big Linux image;
4987 instead, kernel and "initrd" are separate images. This implementation
4988 serves several purposes:
4990 - the same features can be used for other OS or standalone
4991 applications (for instance: using compressed images to reduce the
4992 Flash memory footprint)
4994 - it becomes much easier to port new Linux kernel versions because
4995 lots of low-level, hardware dependent stuff are done by U-Boot
4997 - the same Linux kernel image can now be used with different "initrd"
4998 images; of course this also means that different kernel images can
4999 be run with the same "initrd". This makes testing easier (you don't
5000 have to build a new "zImage.initrd" Linux image when you just
5001 change a file in your "initrd"). Also, a field-upgrade of the
5002 software is easier now.
5008 Porting Linux to U-Boot based systems:
5009 ---------------------------------------
5011 U-Boot cannot save you from doing all the necessary modifications to
5012 configure the Linux device drivers for use with your target hardware
5013 (no, we don't intend to provide a full virtual machine interface to
5016 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5018 Just make sure your machine specific header file (for instance
5019 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5020 Information structure as we define in include/asm-<arch>/u-boot.h,
5021 and make sure that your definition of IMAP_ADDR uses the same value
5022 as your U-Boot configuration in CONFIG_SYS_IMMR.
5025 Configuring the Linux kernel:
5026 -----------------------------
5028 No specific requirements for U-Boot. Make sure you have some root
5029 device (initial ramdisk, NFS) for your target system.
5032 Building a Linux Image:
5033 -----------------------
5035 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5036 not used. If you use recent kernel source, a new build target
5037 "uImage" will exist which automatically builds an image usable by
5038 U-Boot. Most older kernels also have support for a "pImage" target,
5039 which was introduced for our predecessor project PPCBoot and uses a
5040 100% compatible format.
5049 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5050 encapsulate a compressed Linux kernel image with header information,
5051 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5053 * build a standard "vmlinux" kernel image (in ELF binary format):
5055 * convert the kernel into a raw binary image:
5057 ${CROSS_COMPILE}-objcopy -O binary \
5058 -R .note -R .comment \
5059 -S vmlinux linux.bin
5061 * compress the binary image:
5065 * package compressed binary image for U-Boot:
5067 mkimage -A ppc -O linux -T kernel -C gzip \
5068 -a 0 -e 0 -n "Linux Kernel Image" \
5069 -d linux.bin.gz uImage
5072 The "mkimage" tool can also be used to create ramdisk images for use
5073 with U-Boot, either separated from the Linux kernel image, or
5074 combined into one file. "mkimage" encapsulates the images with a 64
5075 byte header containing information about target architecture,
5076 operating system, image type, compression method, entry points, time
5077 stamp, CRC32 checksums, etc.
5079 "mkimage" can be called in two ways: to verify existing images and
5080 print the header information, or to build new images.
5082 In the first form (with "-l" option) mkimage lists the information
5083 contained in the header of an existing U-Boot image; this includes
5084 checksum verification:
5086 tools/mkimage -l image
5087 -l ==> list image header information
5089 The second form (with "-d" option) is used to build a U-Boot image
5090 from a "data file" which is used as image payload:
5092 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5093 -n name -d data_file image
5094 -A ==> set architecture to 'arch'
5095 -O ==> set operating system to 'os'
5096 -T ==> set image type to 'type'
5097 -C ==> set compression type 'comp'
5098 -a ==> set load address to 'addr' (hex)
5099 -e ==> set entry point to 'ep' (hex)
5100 -n ==> set image name to 'name'
5101 -d ==> use image data from 'datafile'
5103 Right now, all Linux kernels for PowerPC systems use the same load
5104 address (0x00000000), but the entry point address depends on the
5107 - 2.2.x kernels have the entry point at 0x0000000C,
5108 - 2.3.x and later kernels have the entry point at 0x00000000.
5110 So a typical call to build a U-Boot image would read:
5112 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5113 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5114 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5115 > examples/uImage.TQM850L
5116 Image Name: 2.4.4 kernel for TQM850L
5117 Created: Wed Jul 19 02:34:59 2000
5118 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5119 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5120 Load Address: 0x00000000
5121 Entry Point: 0x00000000
5123 To verify the contents of the image (or check for corruption):
5125 -> tools/mkimage -l examples/uImage.TQM850L
5126 Image Name: 2.4.4 kernel for TQM850L
5127 Created: Wed Jul 19 02:34:59 2000
5128 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5129 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5130 Load Address: 0x00000000
5131 Entry Point: 0x00000000
5133 NOTE: for embedded systems where boot time is critical you can trade
5134 speed for memory and install an UNCOMPRESSED image instead: this
5135 needs more space in Flash, but boots much faster since it does not
5136 need to be uncompressed:
5138 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5139 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5140 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5141 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5142 > examples/uImage.TQM850L-uncompressed
5143 Image Name: 2.4.4 kernel for TQM850L
5144 Created: Wed Jul 19 02:34:59 2000
5145 Image Type: PowerPC Linux Kernel Image (uncompressed)
5146 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5147 Load Address: 0x00000000
5148 Entry Point: 0x00000000
5151 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5152 when your kernel is intended to use an initial ramdisk:
5154 -> tools/mkimage -n 'Simple Ramdisk Image' \
5155 > -A ppc -O linux -T ramdisk -C gzip \
5156 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5157 Image Name: Simple Ramdisk Image
5158 Created: Wed Jan 12 14:01:50 2000
5159 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5160 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5161 Load Address: 0x00000000
5162 Entry Point: 0x00000000
5165 Installing a Linux Image:
5166 -------------------------
5168 To downloading a U-Boot image over the serial (console) interface,
5169 you must convert the image to S-Record format:
5171 objcopy -I binary -O srec examples/image examples/image.srec
5173 The 'objcopy' does not understand the information in the U-Boot
5174 image header, so the resulting S-Record file will be relative to
5175 address 0x00000000. To load it to a given address, you need to
5176 specify the target address as 'offset' parameter with the 'loads'
5179 Example: install the image to address 0x40100000 (which on the
5180 TQM8xxL is in the first Flash bank):
5182 => erase 40100000 401FFFFF
5188 ## Ready for S-Record download ...
5189 ~>examples/image.srec
5190 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5192 15989 15990 15991 15992
5193 [file transfer complete]
5195 ## Start Addr = 0x00000000
5198 You can check the success of the download using the 'iminfo' command;
5199 this includes a checksum verification so you can be sure no data
5200 corruption happened:
5204 ## Checking Image at 40100000 ...
5205 Image Name: 2.2.13 for initrd on TQM850L
5206 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5207 Data Size: 335725 Bytes = 327 kB = 0 MB
5208 Load Address: 00000000
5209 Entry Point: 0000000c
5210 Verifying Checksum ... OK
5216 The "bootm" command is used to boot an application that is stored in
5217 memory (RAM or Flash). In case of a Linux kernel image, the contents
5218 of the "bootargs" environment variable is passed to the kernel as
5219 parameters. You can check and modify this variable using the
5220 "printenv" and "setenv" commands:
5223 => printenv bootargs
5224 bootargs=root=/dev/ram
5226 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5228 => printenv bootargs
5229 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5232 ## Booting Linux kernel at 40020000 ...
5233 Image Name: 2.2.13 for NFS on TQM850L
5234 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5235 Data Size: 381681 Bytes = 372 kB = 0 MB
5236 Load Address: 00000000
5237 Entry Point: 0000000c
5238 Verifying Checksum ... OK
5239 Uncompressing Kernel Image ... OK
5240 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
5241 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5242 time_init: decrementer frequency = 187500000/60
5243 Calibrating delay loop... 49.77 BogoMIPS
5244 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5247 If you want to boot a Linux kernel with initial RAM disk, you pass
5248 the memory addresses of both the kernel and the initrd image (PPBCOOT
5249 format!) to the "bootm" command:
5251 => imi 40100000 40200000
5253 ## Checking Image at 40100000 ...
5254 Image Name: 2.2.13 for initrd on TQM850L
5255 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5256 Data Size: 335725 Bytes = 327 kB = 0 MB
5257 Load Address: 00000000
5258 Entry Point: 0000000c
5259 Verifying Checksum ... OK
5261 ## Checking Image at 40200000 ...
5262 Image Name: Simple Ramdisk Image
5263 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5264 Data Size: 566530 Bytes = 553 kB = 0 MB
5265 Load Address: 00000000
5266 Entry Point: 00000000
5267 Verifying Checksum ... OK
5269 => bootm 40100000 40200000
5270 ## Booting Linux kernel at 40100000 ...
5271 Image Name: 2.2.13 for initrd on TQM850L
5272 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5273 Data Size: 335725 Bytes = 327 kB = 0 MB
5274 Load Address: 00000000
5275 Entry Point: 0000000c
5276 Verifying Checksum ... OK
5277 Uncompressing Kernel Image ... OK
5278 ## Loading RAMDisk Image at 40200000 ...
5279 Image Name: Simple Ramdisk Image
5280 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5281 Data Size: 566530 Bytes = 553 kB = 0 MB
5282 Load Address: 00000000
5283 Entry Point: 00000000
5284 Verifying Checksum ... OK
5285 Loading Ramdisk ... OK
5286 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
5287 Boot arguments: root=/dev/ram
5288 time_init: decrementer frequency = 187500000/60
5289 Calibrating delay loop... 49.77 BogoMIPS
5291 RAMDISK: Compressed image found at block 0
5292 VFS: Mounted root (ext2 filesystem).
5296 Boot Linux and pass a flat device tree:
5299 First, U-Boot must be compiled with the appropriate defines. See the section
5300 titled "Linux Kernel Interface" above for a more in depth explanation. The
5301 following is an example of how to start a kernel and pass an updated
5307 oft=oftrees/mpc8540ads.dtb
5308 => tftp $oftaddr $oft
5309 Speed: 1000, full duplex
5311 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5312 Filename 'oftrees/mpc8540ads.dtb'.
5313 Load address: 0x300000
5316 Bytes transferred = 4106 (100a hex)
5317 => tftp $loadaddr $bootfile
5318 Speed: 1000, full duplex
5320 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5322 Load address: 0x200000
5323 Loading:############
5325 Bytes transferred = 1029407 (fb51f hex)
5330 => bootm $loadaddr - $oftaddr
5331 ## Booting image at 00200000 ...
5332 Image Name: Linux-2.6.17-dirty
5333 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5334 Data Size: 1029343 Bytes = 1005.2 kB
5335 Load Address: 00000000
5336 Entry Point: 00000000
5337 Verifying Checksum ... OK
5338 Uncompressing Kernel Image ... OK
5339 Booting using flat device tree at 0x300000
5340 Using MPC85xx ADS machine description
5341 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5345 More About U-Boot Image Types:
5346 ------------------------------
5348 U-Boot supports the following image types:
5350 "Standalone Programs" are directly runnable in the environment
5351 provided by U-Boot; it is expected that (if they behave
5352 well) you can continue to work in U-Boot after return from
5353 the Standalone Program.
5354 "OS Kernel Images" are usually images of some Embedded OS which
5355 will take over control completely. Usually these programs
5356 will install their own set of exception handlers, device
5357 drivers, set up the MMU, etc. - this means, that you cannot
5358 expect to re-enter U-Boot except by resetting the CPU.
5359 "RAMDisk Images" are more or less just data blocks, and their
5360 parameters (address, size) are passed to an OS kernel that is
5362 "Multi-File Images" contain several images, typically an OS
5363 (Linux) kernel image and one or more data images like
5364 RAMDisks. This construct is useful for instance when you want
5365 to boot over the network using BOOTP etc., where the boot
5366 server provides just a single image file, but you want to get
5367 for instance an OS kernel and a RAMDisk image.
5369 "Multi-File Images" start with a list of image sizes, each
5370 image size (in bytes) specified by an "uint32_t" in network
5371 byte order. This list is terminated by an "(uint32_t)0".
5372 Immediately after the terminating 0 follow the images, one by
5373 one, all aligned on "uint32_t" boundaries (size rounded up to
5374 a multiple of 4 bytes).
5376 "Firmware Images" are binary images containing firmware (like
5377 U-Boot or FPGA images) which usually will be programmed to
5380 "Script files" are command sequences that will be executed by
5381 U-Boot's command interpreter; this feature is especially
5382 useful when you configure U-Boot to use a real shell (hush)
5383 as command interpreter.
5385 Booting the Linux zImage:
5386 -------------------------
5388 On some platforms, it's possible to boot Linux zImage. This is done
5389 using the "bootz" command. The syntax of "bootz" command is the same
5390 as the syntax of "bootm" command.
5392 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5393 kernel with raw initrd images. The syntax is slightly different, the
5394 address of the initrd must be augmented by it's size, in the following
5395 format: "<initrd addres>:<initrd size>".
5401 One of the features of U-Boot is that you can dynamically load and
5402 run "standalone" applications, which can use some resources of
5403 U-Boot like console I/O functions or interrupt services.
5405 Two simple examples are included with the sources:
5410 'examples/hello_world.c' contains a small "Hello World" Demo
5411 application; it is automatically compiled when you build U-Boot.
5412 It's configured to run at address 0x00040004, so you can play with it
5416 ## Ready for S-Record download ...
5417 ~>examples/hello_world.srec
5418 1 2 3 4 5 6 7 8 9 10 11 ...
5419 [file transfer complete]
5421 ## Start Addr = 0x00040004
5423 => go 40004 Hello World! This is a test.
5424 ## Starting application at 0x00040004 ...
5435 Hit any key to exit ...
5437 ## Application terminated, rc = 0x0
5439 Another example, which demonstrates how to register a CPM interrupt
5440 handler with the U-Boot code, can be found in 'examples/timer.c'.
5441 Here, a CPM timer is set up to generate an interrupt every second.
5442 The interrupt service routine is trivial, just printing a '.'
5443 character, but this is just a demo program. The application can be
5444 controlled by the following keys:
5446 ? - print current values og the CPM Timer registers
5447 b - enable interrupts and start timer
5448 e - stop timer and disable interrupts
5449 q - quit application
5452 ## Ready for S-Record download ...
5453 ~>examples/timer.srec
5454 1 2 3 4 5 6 7 8 9 10 11 ...
5455 [file transfer complete]
5457 ## Start Addr = 0x00040004
5460 ## Starting application at 0x00040004 ...
5463 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5466 [q, b, e, ?] Set interval 1000000 us
5469 [q, b, e, ?] ........
5470 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5473 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5476 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5479 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5481 [q, b, e, ?] ...Stopping timer
5483 [q, b, e, ?] ## Application terminated, rc = 0x0
5489 Over time, many people have reported problems when trying to use the
5490 "minicom" terminal emulation program for serial download. I (wd)
5491 consider minicom to be broken, and recommend not to use it. Under
5492 Unix, I recommend to use C-Kermit for general purpose use (and
5493 especially for kermit binary protocol download ("loadb" command), and
5494 use "cu" for S-Record download ("loads" command). See
5495 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5496 for help with kermit.
5499 Nevertheless, if you absolutely want to use it try adding this
5500 configuration to your "File transfer protocols" section:
5502 Name Program Name U/D FullScr IO-Red. Multi
5503 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5504 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5510 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5511 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5513 Building requires a cross environment; it is known to work on
5514 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5515 need gmake since the Makefiles are not compatible with BSD make).
5516 Note that the cross-powerpc package does not install include files;
5517 attempting to build U-Boot will fail because <machine/ansi.h> is
5518 missing. This file has to be installed and patched manually:
5520 # cd /usr/pkg/cross/powerpc-netbsd/include
5522 # ln -s powerpc machine
5523 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5524 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5526 Native builds *don't* work due to incompatibilities between native
5527 and U-Boot include files.
5529 Booting assumes that (the first part of) the image booted is a
5530 stage-2 loader which in turn loads and then invokes the kernel
5531 proper. Loader sources will eventually appear in the NetBSD source
5532 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5533 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5536 Implementation Internals:
5537 =========================
5539 The following is not intended to be a complete description of every
5540 implementation detail. However, it should help to understand the
5541 inner workings of U-Boot and make it easier to port it to custom
5545 Initial Stack, Global Data:
5546 ---------------------------
5548 The implementation of U-Boot is complicated by the fact that U-Boot
5549 starts running out of ROM (flash memory), usually without access to
5550 system RAM (because the memory controller is not initialized yet).
5551 This means that we don't have writable Data or BSS segments, and BSS
5552 is not initialized as zero. To be able to get a C environment working
5553 at all, we have to allocate at least a minimal stack. Implementation
5554 options for this are defined and restricted by the CPU used: Some CPU
5555 models provide on-chip memory (like the IMMR area on MPC8xx and
5556 MPC826x processors), on others (parts of) the data cache can be
5557 locked as (mis-) used as memory, etc.
5559 Chris Hallinan posted a good summary of these issues to the
5560 U-Boot mailing list:
5562 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5563 From: "Chris Hallinan" <clh@net1plus.com>
5564 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5567 Correct me if I'm wrong, folks, but the way I understand it
5568 is this: Using DCACHE as initial RAM for Stack, etc, does not
5569 require any physical RAM backing up the cache. The cleverness
5570 is that the cache is being used as a temporary supply of
5571 necessary storage before the SDRAM controller is setup. It's
5572 beyond the scope of this list to explain the details, but you
5573 can see how this works by studying the cache architecture and
5574 operation in the architecture and processor-specific manuals.
5576 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5577 is another option for the system designer to use as an
5578 initial stack/RAM area prior to SDRAM being available. Either
5579 option should work for you. Using CS 4 should be fine if your
5580 board designers haven't used it for something that would
5581 cause you grief during the initial boot! It is frequently not
5584 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5585 with your processor/board/system design. The default value
5586 you will find in any recent u-boot distribution in
5587 walnut.h should work for you. I'd set it to a value larger
5588 than your SDRAM module. If you have a 64MB SDRAM module, set
5589 it above 400_0000. Just make sure your board has no resources
5590 that are supposed to respond to that address! That code in
5591 start.S has been around a while and should work as is when
5592 you get the config right.
5597 It is essential to remember this, since it has some impact on the C
5598 code for the initialization procedures:
5600 * Initialized global data (data segment) is read-only. Do not attempt
5603 * Do not use any uninitialized global data (or implicitely initialized
5604 as zero data - BSS segment) at all - this is undefined, initiali-
5605 zation is performed later (when relocating to RAM).
5607 * Stack space is very limited. Avoid big data buffers or things like
5610 Having only the stack as writable memory limits means we cannot use
5611 normal global data to share information beween the code. But it
5612 turned out that the implementation of U-Boot can be greatly
5613 simplified by making a global data structure (gd_t) available to all
5614 functions. We could pass a pointer to this data as argument to _all_
5615 functions, but this would bloat the code. Instead we use a feature of
5616 the GCC compiler (Global Register Variables) to share the data: we
5617 place a pointer (gd) to the global data into a register which we
5618 reserve for this purpose.
5620 When choosing a register for such a purpose we are restricted by the
5621 relevant (E)ABI specifications for the current architecture, and by
5622 GCC's implementation.
5624 For PowerPC, the following registers have specific use:
5626 R2: reserved for system use
5627 R3-R4: parameter passing and return values
5628 R5-R10: parameter passing
5629 R13: small data area pointer
5633 (U-Boot also uses R12 as internal GOT pointer. r12
5634 is a volatile register so r12 needs to be reset when
5635 going back and forth between asm and C)
5637 ==> U-Boot will use R2 to hold a pointer to the global data
5639 Note: on PPC, we could use a static initializer (since the
5640 address of the global data structure is known at compile time),
5641 but it turned out that reserving a register results in somewhat
5642 smaller code - although the code savings are not that big (on
5643 average for all boards 752 bytes for the whole U-Boot image,
5644 624 text + 127 data).
5646 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5647 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5649 ==> U-Boot will use P3 to hold a pointer to the global data
5651 On ARM, the following registers are used:
5653 R0: function argument word/integer result
5654 R1-R3: function argument word
5655 R9: platform specific
5656 R10: stack limit (used only if stack checking is enabled)
5657 R11: argument (frame) pointer
5658 R12: temporary workspace
5661 R15: program counter
5663 ==> U-Boot will use R9 to hold a pointer to the global data
5665 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5667 On Nios II, the ABI is documented here:
5668 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5670 ==> U-Boot will use gp to hold a pointer to the global data
5672 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5673 to access small data sections, so gp is free.
5675 On NDS32, the following registers are used:
5677 R0-R1: argument/return
5679 R15: temporary register for assembler
5680 R16: trampoline register
5681 R28: frame pointer (FP)
5682 R29: global pointer (GP)
5683 R30: link register (LP)
5684 R31: stack pointer (SP)
5685 PC: program counter (PC)
5687 ==> U-Boot will use R10 to hold a pointer to the global data
5689 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5690 or current versions of GCC may "optimize" the code too much.
5695 U-Boot runs in system state and uses physical addresses, i.e. the
5696 MMU is not used either for address mapping nor for memory protection.
5698 The available memory is mapped to fixed addresses using the memory
5699 controller. In this process, a contiguous block is formed for each
5700 memory type (Flash, SDRAM, SRAM), even when it consists of several
5701 physical memory banks.
5703 U-Boot is installed in the first 128 kB of the first Flash bank (on
5704 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5705 booting and sizing and initializing DRAM, the code relocates itself
5706 to the upper end of DRAM. Immediately below the U-Boot code some
5707 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5708 configuration setting]. Below that, a structure with global Board
5709 Info data is placed, followed by the stack (growing downward).
5711 Additionally, some exception handler code is copied to the low 8 kB
5712 of DRAM (0x00000000 ... 0x00001FFF).
5714 So a typical memory configuration with 16 MB of DRAM could look like
5717 0x0000 0000 Exception Vector code
5720 0x0000 2000 Free for Application Use
5726 0x00FB FF20 Monitor Stack (Growing downward)
5727 0x00FB FFAC Board Info Data and permanent copy of global data
5728 0x00FC 0000 Malloc Arena
5731 0x00FE 0000 RAM Copy of Monitor Code
5732 ... eventually: LCD or video framebuffer
5733 ... eventually: pRAM (Protected RAM - unchanged by reset)
5734 0x00FF FFFF [End of RAM]
5737 System Initialization:
5738 ----------------------
5740 In the reset configuration, U-Boot starts at the reset entry point
5741 (on most PowerPC systems at address 0x00000100). Because of the reset
5742 configuration for CS0# this is a mirror of the onboard Flash memory.
5743 To be able to re-map memory U-Boot then jumps to its link address.
5744 To be able to implement the initialization code in C, a (small!)
5745 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5746 which provide such a feature like MPC8xx or MPC8260), or in a locked
5747 part of the data cache. After that, U-Boot initializes the CPU core,
5748 the caches and the SIU.
5750 Next, all (potentially) available memory banks are mapped using a
5751 preliminary mapping. For example, we put them on 512 MB boundaries
5752 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5753 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5754 programmed for SDRAM access. Using the temporary configuration, a
5755 simple memory test is run that determines the size of the SDRAM
5758 When there is more than one SDRAM bank, and the banks are of
5759 different size, the largest is mapped first. For equal size, the first
5760 bank (CS2#) is mapped first. The first mapping is always for address
5761 0x00000000, with any additional banks following immediately to create
5762 contiguous memory starting from 0.
5764 Then, the monitor installs itself at the upper end of the SDRAM area
5765 and allocates memory for use by malloc() and for the global Board
5766 Info data; also, the exception vector code is copied to the low RAM
5767 pages, and the final stack is set up.
5769 Only after this relocation will you have a "normal" C environment;
5770 until that you are restricted in several ways, mostly because you are
5771 running from ROM, and because the code will have to be relocated to a
5775 U-Boot Porting Guide:
5776 ----------------------
5778 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5782 int main(int argc, char *argv[])
5784 sighandler_t no_more_time;
5786 signal(SIGALRM, no_more_time);
5787 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5789 if (available_money > available_manpower) {
5790 Pay consultant to port U-Boot;
5794 Download latest U-Boot source;
5796 Subscribe to u-boot mailing list;
5799 email("Hi, I am new to U-Boot, how do I get started?");
5802 Read the README file in the top level directory;
5803 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5804 Read applicable doc/*.README;
5805 Read the source, Luke;
5806 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5809 if (available_money > toLocalCurrency ($2500))
5812 Add a lot of aggravation and time;
5814 if (a similar board exists) { /* hopefully... */
5815 cp -a board/<similar> board/<myboard>
5816 cp include/configs/<similar>.h include/configs/<myboard>.h
5818 Create your own board support subdirectory;
5819 Create your own board include/configs/<myboard>.h file;
5821 Edit new board/<myboard> files
5822 Edit new include/configs/<myboard>.h
5827 Add / modify source code;
5831 email("Hi, I am having problems...");
5833 Send patch file to the U-Boot email list;
5834 if (reasonable critiques)
5835 Incorporate improvements from email list code review;
5837 Defend code as written;
5843 void no_more_time (int sig)
5852 All contributions to U-Boot should conform to the Linux kernel
5853 coding style; see the file "Documentation/CodingStyle" and the script
5854 "scripts/Lindent" in your Linux kernel source directory.
5856 Source files originating from a different project (for example the
5857 MTD subsystem) are generally exempt from these guidelines and are not
5858 reformated to ease subsequent migration to newer versions of those
5861 Please note that U-Boot is implemented in C (and to some small parts in
5862 Assembler); no C++ is used, so please do not use C++ style comments (//)
5865 Please also stick to the following formatting rules:
5866 - remove any trailing white space
5867 - use TAB characters for indentation and vertical alignment, not spaces
5868 - make sure NOT to use DOS '\r\n' line feeds
5869 - do not add more than 2 consecutive empty lines to source files
5870 - do not add trailing empty lines to source files
5872 Submissions which do not conform to the standards may be returned
5873 with a request to reformat the changes.
5879 Since the number of patches for U-Boot is growing, we need to
5880 establish some rules. Submissions which do not conform to these rules
5881 may be rejected, even when they contain important and valuable stuff.
5883 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5885 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5886 see http://lists.denx.de/mailman/listinfo/u-boot
5888 When you send a patch, please include the following information with
5891 * For bug fixes: a description of the bug and how your patch fixes
5892 this bug. Please try to include a way of demonstrating that the
5893 patch actually fixes something.
5895 * For new features: a description of the feature and your
5898 * A CHANGELOG entry as plaintext (separate from the patch)
5900 * For major contributions, your entry to the CREDITS file
5902 * When you add support for a new board, don't forget to add a
5903 maintainer e-mail address to the boards.cfg file, too.
5905 * If your patch adds new configuration options, don't forget to
5906 document these in the README file.
5908 * The patch itself. If you are using git (which is *strongly*
5909 recommended) you can easily generate the patch using the
5910 "git format-patch". If you then use "git send-email" to send it to
5911 the U-Boot mailing list, you will avoid most of the common problems
5912 with some other mail clients.
5914 If you cannot use git, use "diff -purN OLD NEW". If your version of
5915 diff does not support these options, then get the latest version of
5918 The current directory when running this command shall be the parent
5919 directory of the U-Boot source tree (i. e. please make sure that
5920 your patch includes sufficient directory information for the
5923 We prefer patches as plain text. MIME attachments are discouraged,
5924 and compressed attachments must not be used.
5926 * If one logical set of modifications affects or creates several
5927 files, all these changes shall be submitted in a SINGLE patch file.
5929 * Changesets that contain different, unrelated modifications shall be
5930 submitted as SEPARATE patches, one patch per changeset.
5935 * Before sending the patch, run the MAKEALL script on your patched
5936 source tree and make sure that no errors or warnings are reported
5937 for any of the boards.
5939 * Keep your modifications to the necessary minimum: A patch
5940 containing several unrelated changes or arbitrary reformats will be
5941 returned with a request to re-formatting / split it.
5943 * If you modify existing code, make sure that your new code does not
5944 add to the memory footprint of the code ;-) Small is beautiful!
5945 When adding new features, these should compile conditionally only
5946 (using #ifdef), and the resulting code with the new feature
5947 disabled must not need more memory than the old code without your
5950 * Remember that there is a size limit of 100 kB per message on the
5951 u-boot mailing list. Bigger patches will be moderated. If they are
5952 reasonable and not too big, they will be acknowledged. But patches
5953 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob