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 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
186 /mpc5xx Files specific to Freescale MPC5xx CPUs
187 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
188 /mpc8xx Files specific to Freescale MPC8xx CPUs
189 /mpc824x Files specific to Freescale MPC824x CPUs
190 /mpc8260 Files specific to Freescale MPC8260 CPUs
191 /mpc85xx Files specific to Freescale MPC85xx CPUs
192 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
193 /lib Architecture specific library files
194 /sh Files generic to SH architecture
195 /cpu CPU specific files
196 /sh2 Files specific to sh2 CPUs
197 /sh3 Files specific to sh3 CPUs
198 /sh4 Files specific to sh4 CPUs
199 /lib Architecture specific library files
200 /sparc Files generic to SPARC architecture
201 /cpu CPU specific files
202 /leon2 Files specific to Gaisler LEON2 SPARC CPU
203 /leon3 Files specific to Gaisler LEON3 SPARC CPU
204 /lib Architecture specific library files
205 /x86 Files generic to x86 architecture
206 /cpu CPU specific files
207 /lib Architecture specific library files
208 /api Machine/arch independent API for external apps
209 /board Board dependent files
210 /common Misc architecture independent functions
211 /disk Code for disk drive partition handling
212 /doc Documentation (don't expect too much)
213 /drivers Commonly used device drivers
214 /dts Contains Makefile for building internal U-Boot fdt.
215 /examples Example code for standalone applications, etc.
216 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
217 /include Header Files
218 /lib Files generic to all architectures
219 /libfdt Library files to support flattened device trees
220 /lzma Library files to support LZMA decompression
221 /lzo Library files to support LZO decompression
223 /post Power On Self Test
224 /spl Secondary Program Loader framework
225 /tools Tools to build S-Record or U-Boot images, etc.
227 Software Configuration:
228 =======================
230 Configuration is usually done using C preprocessor defines; the
231 rationale behind that is to avoid dead code whenever possible.
233 There are two classes of configuration variables:
235 * Configuration _OPTIONS_:
236 These are selectable by the user and have names beginning with
239 * Configuration _SETTINGS_:
240 These depend on the hardware etc. and should not be meddled with if
241 you don't know what you're doing; they have names beginning with
244 Later we will add a configuration tool - probably similar to or even
245 identical to what's used for the Linux kernel. Right now, we have to
246 do the configuration by hand, which means creating some symbolic
247 links and editing some configuration files. We use the TQM8xxL boards
251 Selection of Processor Architecture and Board Type:
252 ---------------------------------------------------
254 For all supported boards there are ready-to-use default
255 configurations available; just type "make <board_name>_config".
257 Example: For a TQM823L module type:
262 For the Cogent platform, you need to specify the CPU type as well;
263 e.g. "make cogent_mpc8xx_config". And also configure the cogent
264 directory according to the instructions in cogent/README.
267 Configuration Options:
268 ----------------------
270 Configuration depends on the combination of board and CPU type; all
271 such information is kept in a configuration file
272 "include/configs/<board_name>.h".
274 Example: For a TQM823L module, all configuration settings are in
275 "include/configs/TQM823L.h".
278 Many of the options are named exactly as the corresponding Linux
279 kernel configuration options. The intention is to make it easier to
280 build a config tool - later.
283 The following options need to be configured:
285 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
287 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
289 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
290 Define exactly one, e.g. CONFIG_ATSTK1002
292 - CPU Module Type: (if CONFIG_COGENT is defined)
293 Define exactly one of
295 --- FIXME --- not tested yet:
296 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
297 CONFIG_CMA287_23, CONFIG_CMA287_50
299 - Motherboard Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
301 CONFIG_CMA101, CONFIG_CMA102
303 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
304 Define one or more of
307 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
308 Define one or more of
309 CONFIG_LCD_HEARTBEAT - update a character position on
310 the LCD display every second with
313 - Board flavour: (if CONFIG_MPC8260ADS is defined)
316 CONFIG_SYS_8260ADS - original MPC8260ADS
317 CONFIG_SYS_8266ADS - MPC8266ADS
318 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
319 CONFIG_SYS_8272ADS - MPC8272ADS
321 - Marvell Family Member
322 CONFIG_SYS_MVFS - define it if you want to enable
323 multiple fs option at one time
324 for marvell soc family
326 - MPC824X Family Member (if CONFIG_MPC824X is defined)
327 Define exactly one of
328 CONFIG_MPC8240, CONFIG_MPC8245
330 - 8xx CPU Options: (if using an MPC8xx CPU)
331 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
332 get_gclk_freq() cannot work
333 e.g. if there is no 32KHz
334 reference PIT/RTC clock
335 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
338 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
339 CONFIG_SYS_8xx_CPUCLK_MIN
340 CONFIG_SYS_8xx_CPUCLK_MAX
341 CONFIG_8xx_CPUCLK_DEFAULT
342 See doc/README.MPC866
344 CONFIG_SYS_MEASURE_CPUCLK
346 Define this to measure the actual CPU clock instead
347 of relying on the correctness of the configured
348 values. Mostly useful for board bringup to make sure
349 the PLL is locked at the intended frequency. Note
350 that this requires a (stable) reference clock (32 kHz
351 RTC clock or CONFIG_SYS_8XX_XIN)
353 CONFIG_SYS_DELAYED_ICACHE
355 Define this option if you want to enable the
356 ICache only when Code runs from RAM.
361 Specifies that the core is a 64-bit PowerPC implementation (implements
362 the "64" category of the Power ISA). This is necessary for ePAPR
363 compliance, among other possible reasons.
365 CONFIG_SYS_FSL_TBCLK_DIV
367 Defines the core time base clock divider ratio compared to the
368 system clock. On most PQ3 devices this is 8, on newer QorIQ
369 devices it can be 16 or 32. The ratio varies from SoC to Soc.
371 CONFIG_SYS_FSL_PCIE_COMPAT
373 Defines the string to utilize when trying to match PCIe device
374 tree nodes for the given platform.
376 CONFIG_SYS_PPC_E500_DEBUG_TLB
378 Enables a temporary TLB entry to be used during boot to work
379 around limitations in e500v1 and e500v2 external debugger
380 support. This reduces the portions of the boot code where
381 breakpoints and single stepping do not work. The value of this
382 symbol should be set to the TLB1 entry to be used for this
385 CONFIG_SYS_FSL_ERRATUM_A004510
387 Enables a workaround for erratum A004510. If set,
388 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
389 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
391 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
392 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
394 Defines one or two SoC revisions (low 8 bits of SVR)
395 for which the A004510 workaround should be applied.
397 The rest of SVR is either not relevant to the decision
398 of whether the erratum is present (e.g. p2040 versus
399 p2041) or is implied by the build target, which controls
400 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
402 See Freescale App Note 4493 for more information about
405 CONFIG_A003399_NOR_WORKAROUND
406 Enables a workaround for IFC erratum A003399. It is only
407 requred during NOR boot.
409 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
411 This is the value to write into CCSR offset 0x18600
412 according to the A004510 workaround.
414 CONFIG_SYS_FSL_DSP_DDR_ADDR
415 This value denotes start offset of DDR memory which is
416 connected exclusively to the DSP cores.
418 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
419 This value denotes start offset of M2 memory
420 which is directly connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
423 This value denotes start offset of M3 memory which is directly
424 connected to the DSP core.
426 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
427 This value denotes start offset of DSP CCSR space.
429 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
430 Single Source Clock is clocking mode present in some of FSL SoC's.
431 In this mode, a single differential clock is used to supply
432 clocks to the sysclock, ddrclock and usbclock.
434 CONFIG_SYS_CPC_REINIT_F
435 This CONFIG is defined when the CPC is configured as SRAM at the
436 time of U-boot entry and is required to be re-initialized.
439 Inidcates this SoC supports deep sleep feature. If deep sleep is
440 supported, core will start to execute uboot when wakes up.
442 - Generic CPU options:
443 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
445 Defines the endianess of the CPU. Implementation of those
446 values is arch specific.
449 Freescale DDR driver in use. This type of DDR controller is
450 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
453 CONFIG_SYS_FSL_DDR_ADDR
454 Freescale DDR memory-mapped register base.
456 CONFIG_SYS_FSL_DDR_EMU
457 Specify emulator support for DDR. Some DDR features such as
458 deskew training are not available.
460 CONFIG_SYS_FSL_DDRC_GEN1
461 Freescale DDR1 controller.
463 CONFIG_SYS_FSL_DDRC_GEN2
464 Freescale DDR2 controller.
466 CONFIG_SYS_FSL_DDRC_GEN3
467 Freescale DDR3 controller.
469 CONFIG_SYS_FSL_DDRC_GEN4
470 Freescale DDR4 controller.
472 CONFIG_SYS_FSL_DDRC_ARM_GEN3
473 Freescale DDR3 controller for ARM-based SoCs.
476 Board config to use DDR1. It can be enabled for SoCs with
477 Freescale DDR1 or DDR2 controllers, depending on the board
481 Board config to use DDR2. It can be eanbeld for SoCs with
482 Freescale DDR2 or DDR3 controllers, depending on the board
486 Board config to use DDR3. It can be enabled for SoCs with
487 Freescale DDR3 or DDR3L controllers.
490 Board config to use DDR3L. It can be enabled for SoCs with
494 Board config to use DDR4. It can be enabled for SoCs with
497 CONFIG_SYS_FSL_IFC_BE
498 Defines the IFC controller register space as Big Endian
500 CONFIG_SYS_FSL_IFC_LE
501 Defines the IFC controller register space as Little Endian
503 CONFIG_SYS_FSL_PBL_PBI
504 It enables addition of RCW (Power on reset configuration) in built image.
505 Please refer doc/README.pblimage for more details
507 CONFIG_SYS_FSL_PBL_RCW
508 It adds PBI(pre-boot instructions) commands in u-boot build image.
509 PBI commands can be used to configure SoC before it starts the execution.
510 Please refer doc/README.pblimage for more details
513 It adds a target to create boot binary having SPL binary in PBI format
514 concatenated with u-boot binary.
516 CONFIG_SYS_FSL_DDR_BE
517 Defines the DDR controller register space as Big Endian
519 CONFIG_SYS_FSL_DDR_LE
520 Defines the DDR controller register space as Little Endian
522 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
523 Physical address from the view of DDR controllers. It is the
524 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
525 it could be different for ARM SoCs.
527 CONFIG_SYS_FSL_DDR_INTLV_256B
528 DDR controller interleaving on 256-byte. This is a special
529 interleaving mode, handled by Dickens for Freescale layerscape
532 - Intel Monahans options:
533 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
535 Defines the Monahans run mode to oscillator
536 ratio. Valid values are 8, 16, 24, 31. The core
537 frequency is this value multiplied by 13 MHz.
539 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
541 Defines the Monahans turbo mode to oscillator
542 ratio. Valid values are 1 (default if undefined) and
543 2. The core frequency as calculated above is multiplied
547 CONFIG_SYS_INIT_SP_OFFSET
549 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
550 pointer. This is needed for the temporary stack before
553 CONFIG_SYS_MIPS_CACHE_MODE
555 Cache operation mode for the MIPS CPU.
556 See also arch/mips/include/asm/mipsregs.h.
558 CONF_CM_CACHABLE_NO_WA
561 CONF_CM_CACHABLE_NONCOHERENT
565 CONF_CM_CACHABLE_ACCELERATED
567 CONFIG_SYS_XWAY_EBU_BOOTCFG
569 Special option for Lantiq XWAY SoCs for booting from NOR flash.
570 See also arch/mips/cpu/mips32/start.S.
572 CONFIG_XWAY_SWAP_BYTES
574 Enable compilation of tools/xway-swap-bytes needed for Lantiq
575 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
576 be swapped if a flash programmer is used.
579 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
581 Select high exception vectors of the ARM core, e.g., do not
582 clear the V bit of the c1 register of CP15.
584 CONFIG_SYS_THUMB_BUILD
586 Use this flag to build U-Boot using the Thumb instruction
587 set for ARM architectures. Thumb instruction set provides
588 better code density. For ARM architectures that support
589 Thumb2 this flag will result in Thumb2 code generated by
592 CONFIG_ARM_ERRATA_716044
593 CONFIG_ARM_ERRATA_742230
594 CONFIG_ARM_ERRATA_743622
595 CONFIG_ARM_ERRATA_751472
596 CONFIG_ARM_ERRATA_794072
597 CONFIG_ARM_ERRATA_761320
599 If set, the workarounds for these ARM errata are applied early
600 during U-Boot startup. Note that these options force the
601 workarounds to be applied; no CPU-type/version detection
602 exists, unlike the similar options in the Linux kernel. Do not
603 set these options unless they apply!
608 The frequency of the timer returned by get_timer().
609 get_timer() must operate in milliseconds and this CONFIG
610 option must be set to 1000.
612 - Linux Kernel Interface:
615 U-Boot stores all clock information in Hz
616 internally. For binary compatibility with older Linux
617 kernels (which expect the clocks passed in the
618 bd_info data to be in MHz) the environment variable
619 "clocks_in_mhz" can be defined so that U-Boot
620 converts clock data to MHZ before passing it to the
622 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
623 "clocks_in_mhz=1" is automatically included in the
626 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
628 When transferring memsize parameter to linux, some versions
629 expect it to be in bytes, others in MB.
630 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
634 New kernel versions are expecting firmware settings to be
635 passed using flattened device trees (based on open firmware
639 * New libfdt-based support
640 * Adds the "fdt" command
641 * The bootm command automatically updates the fdt
643 OF_CPU - The proper name of the cpus node (only required for
644 MPC512X and MPC5xxx based boards).
645 OF_SOC - The proper name of the soc node (only required for
646 MPC512X and MPC5xxx based boards).
647 OF_TBCLK - The timebase frequency.
648 OF_STDOUT_PATH - The path to the console device
650 boards with QUICC Engines require OF_QE to set UCC MAC
653 CONFIG_OF_BOARD_SETUP
655 Board code has addition modification that it wants to make
656 to the flat device tree before handing it off to the kernel
660 This define fills in the correct boot CPU in the boot
661 param header, the default value is zero if undefined.
665 U-Boot can detect if an IDE device is present or not.
666 If not, and this new config option is activated, U-Boot
667 removes the ATA node from the DTS before booting Linux,
668 so the Linux IDE driver does not probe the device and
669 crash. This is needed for buggy hardware (uc101) where
670 no pull down resistor is connected to the signal IDE5V_DD7.
672 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
674 This setting is mandatory for all boards that have only one
675 machine type and must be used to specify the machine type
676 number as it appears in the ARM machine registry
677 (see http://www.arm.linux.org.uk/developer/machines/).
678 Only boards that have multiple machine types supported
679 in a single configuration file and the machine type is
680 runtime discoverable, do not have to use this setting.
682 - vxWorks boot parameters:
684 bootvx constructs a valid bootline using the following
685 environments variables: bootfile, ipaddr, serverip, hostname.
686 It loads the vxWorks image pointed bootfile.
688 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
689 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
690 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
691 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
693 CONFIG_SYS_VXWORKS_ADD_PARAMS
695 Add it at the end of the bootline. E.g "u=username pw=secret"
697 Note: If a "bootargs" environment is defined, it will overwride
698 the defaults discussed just above.
700 - Cache Configuration:
701 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
702 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
703 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
705 - Cache Configuration for ARM:
706 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
708 CONFIG_SYS_PL310_BASE - Physical base address of PL310
709 controller register space
714 Define this if you want support for Amba PrimeCell PL010 UARTs.
718 Define this if you want support for Amba PrimeCell PL011 UARTs.
722 If you have Amba PrimeCell PL011 UARTs, set this variable to
723 the clock speed of the UARTs.
727 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
728 define this to a list of base addresses for each (supported)
729 port. See e.g. include/configs/versatile.h
731 CONFIG_PL011_SERIAL_RLCR
733 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
734 have separate receive and transmit line control registers. Set
735 this variable to initialize the extra register.
737 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
739 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
740 boot loader that has already initialized the UART. Define this
741 variable to flush the UART at init time.
745 Depending on board, define exactly one serial port
746 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
747 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
748 console by defining CONFIG_8xx_CONS_NONE
750 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
751 port routines must be defined elsewhere
752 (i.e. serial_init(), serial_getc(), ...)
755 Enables console device for a color framebuffer. Needs following
756 defines (cf. smiLynxEM, i8042)
757 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
759 VIDEO_HW_RECTFILL graphic chip supports
762 VIDEO_HW_BITBLT graphic chip supports
763 bit-blit (cf. smiLynxEM)
764 VIDEO_VISIBLE_COLS visible pixel columns
766 VIDEO_VISIBLE_ROWS visible pixel rows
767 VIDEO_PIXEL_SIZE bytes per pixel
768 VIDEO_DATA_FORMAT graphic data format
769 (0-5, cf. cfb_console.c)
770 VIDEO_FB_ADRS framebuffer address
771 VIDEO_KBD_INIT_FCT keyboard int fct
772 (i.e. i8042_kbd_init())
773 VIDEO_TSTC_FCT test char fct
775 VIDEO_GETC_FCT get char fct
777 CONFIG_CONSOLE_CURSOR cursor drawing on/off
778 (requires blink timer
780 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
781 CONFIG_CONSOLE_TIME display time/date info in
783 (requires CONFIG_CMD_DATE)
784 CONFIG_VIDEO_LOGO display Linux logo in
786 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
787 linux_logo.h for logo.
788 Requires CONFIG_VIDEO_LOGO
789 CONFIG_CONSOLE_EXTRA_INFO
790 additional board info beside
793 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
794 a limited number of ANSI escape sequences (cursor control,
795 erase functions and limited graphics rendition control).
797 When CONFIG_CFB_CONSOLE is defined, video console is
798 default i/o. Serial console can be forced with
799 environment 'console=serial'.
801 When CONFIG_SILENT_CONSOLE is defined, all console
802 messages (by U-Boot and Linux!) can be silenced with
803 the "silent" environment variable. See
804 doc/README.silent for more information.
806 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
808 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
812 CONFIG_BAUDRATE - in bps
813 Select one of the baudrates listed in
814 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
817 - Console Rx buffer length
818 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
819 the maximum receive buffer length for the SMC.
820 This option is actual only for 82xx and 8xx possible.
821 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
822 must be defined, to setup the maximum idle timeout for
825 - Pre-Console Buffer:
826 Prior to the console being initialised (i.e. serial UART
827 initialised etc) all console output is silently discarded.
828 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
829 buffer any console messages prior to the console being
830 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
831 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
832 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
833 bytes are output before the console is initialised, the
834 earlier bytes are discarded.
836 'Sane' compilers will generate smaller code if
837 CONFIG_PRE_CON_BUF_SZ is a power of 2
839 - Safe printf() functions
840 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
841 the printf() functions. These are defined in
842 include/vsprintf.h and include snprintf(), vsnprintf() and
843 so on. Code size increase is approximately 300-500 bytes.
844 If this option is not given then these functions will
845 silently discard their buffer size argument - this means
846 you are not getting any overflow checking in this case.
848 - Boot Delay: CONFIG_BOOTDELAY - in seconds
849 Delay before automatically booting the default image;
850 set to -1 to disable autoboot.
851 set to -2 to autoboot with no delay and not check for abort
852 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
854 See doc/README.autoboot for these options that
855 work with CONFIG_BOOTDELAY. None are required.
856 CONFIG_BOOT_RETRY_TIME
857 CONFIG_BOOT_RETRY_MIN
858 CONFIG_AUTOBOOT_KEYED
859 CONFIG_AUTOBOOT_PROMPT
860 CONFIG_AUTOBOOT_DELAY_STR
861 CONFIG_AUTOBOOT_STOP_STR
862 CONFIG_AUTOBOOT_DELAY_STR2
863 CONFIG_AUTOBOOT_STOP_STR2
864 CONFIG_ZERO_BOOTDELAY_CHECK
865 CONFIG_RESET_TO_RETRY
869 Only needed when CONFIG_BOOTDELAY is enabled;
870 define a command string that is automatically executed
871 when no character is read on the console interface
872 within "Boot Delay" after reset.
875 This can be used to pass arguments to the bootm
876 command. The value of CONFIG_BOOTARGS goes into the
877 environment value "bootargs".
879 CONFIG_RAMBOOT and CONFIG_NFSBOOT
880 The value of these goes into the environment as
881 "ramboot" and "nfsboot" respectively, and can be used
882 as a convenience, when switching between booting from
886 CONFIG_BOOTCOUNT_LIMIT
887 Implements a mechanism for detecting a repeating reboot
889 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
892 If no softreset save registers are found on the hardware
893 "bootcount" is stored in the environment. To prevent a
894 saveenv on all reboots, the environment variable
895 "upgrade_available" is used. If "upgrade_available" is
896 0, "bootcount" is always 0, if "upgrade_available" is
897 1 "bootcount" is incremented in the environment.
898 So the Userspace Applikation must set the "upgrade_available"
899 and "bootcount" variable to 0, if a boot was successfully.
904 When this option is #defined, the existence of the
905 environment variable "preboot" will be checked
906 immediately before starting the CONFIG_BOOTDELAY
907 countdown and/or running the auto-boot command resp.
908 entering interactive mode.
910 This feature is especially useful when "preboot" is
911 automatically generated or modified. For an example
912 see the LWMON board specific code: here "preboot" is
913 modified when the user holds down a certain
914 combination of keys on the (special) keyboard when
917 - Serial Download Echo Mode:
919 If defined to 1, all characters received during a
920 serial download (using the "loads" command) are
921 echoed back. This might be needed by some terminal
922 emulations (like "cu"), but may as well just take
923 time on others. This setting #define's the initial
924 value of the "loads_echo" environment variable.
926 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
928 Select one of the baudrates listed in
929 CONFIG_SYS_BAUDRATE_TABLE, see below.
932 Monitor commands can be included or excluded
933 from the build by using the #include files
934 <config_cmd_all.h> and #undef'ing unwanted
935 commands, or using <config_cmd_default.h>
936 and augmenting with additional #define's
939 The default command configuration includes all commands
940 except those marked below with a "*".
942 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
943 CONFIG_CMD_ASKENV * ask for env variable
944 CONFIG_CMD_BDI bdinfo
945 CONFIG_CMD_BEDBUG * Include BedBug Debugger
946 CONFIG_CMD_BMP * BMP support
947 CONFIG_CMD_BSP * Board specific commands
948 CONFIG_CMD_BOOTD bootd
949 CONFIG_CMD_CACHE * icache, dcache
950 CONFIG_CMD_CLK * clock command support
951 CONFIG_CMD_CONSOLE coninfo
952 CONFIG_CMD_CRC32 * crc32
953 CONFIG_CMD_DATE * support for RTC, date/time...
954 CONFIG_CMD_DHCP * DHCP support
955 CONFIG_CMD_DIAG * Diagnostics
956 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
957 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
958 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
959 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
960 CONFIG_CMD_DTT * Digital Therm and Thermostat
961 CONFIG_CMD_ECHO echo arguments
962 CONFIG_CMD_EDITENV edit env variable
963 CONFIG_CMD_EEPROM * EEPROM read/write support
964 CONFIG_CMD_ELF * bootelf, bootvx
965 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
966 CONFIG_CMD_ENV_FLAGS * display details about env flags
967 CONFIG_CMD_ENV_EXISTS * check existence of env variable
968 CONFIG_CMD_EXPORTENV * export the environment
969 CONFIG_CMD_EXT2 * ext2 command support
970 CONFIG_CMD_EXT4 * ext4 command support
971 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
972 that work for multiple fs types
973 CONFIG_CMD_SAVEENV saveenv
974 CONFIG_CMD_FDC * Floppy Disk Support
975 CONFIG_CMD_FAT * FAT command support
976 CONFIG_CMD_FLASH flinfo, erase, protect
977 CONFIG_CMD_FPGA FPGA device initialization support
978 CONFIG_CMD_FUSE * Device fuse support
979 CONFIG_CMD_GETTIME * Get time since boot
980 CONFIG_CMD_GO * the 'go' command (exec code)
981 CONFIG_CMD_GREPENV * search environment
982 CONFIG_CMD_HASH * calculate hash / digest
983 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
984 CONFIG_CMD_I2C * I2C serial bus support
985 CONFIG_CMD_IDE * IDE harddisk support
986 CONFIG_CMD_IMI iminfo
987 CONFIG_CMD_IMLS List all images found in NOR flash
988 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
989 CONFIG_CMD_IMMAP * IMMR dump support
990 CONFIG_CMD_IMPORTENV * import an environment
991 CONFIG_CMD_INI * import data from an ini file into the env
992 CONFIG_CMD_IRQ * irqinfo
993 CONFIG_CMD_ITEST Integer/string test of 2 values
994 CONFIG_CMD_JFFS2 * JFFS2 Support
995 CONFIG_CMD_KGDB * kgdb
996 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
997 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
999 CONFIG_CMD_LOADB loadb
1000 CONFIG_CMD_LOADS loads
1001 CONFIG_CMD_MD5SUM * print md5 message digest
1002 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1003 CONFIG_CMD_MEMINFO * Display detailed memory information
1004 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1006 CONFIG_CMD_MEMTEST * mtest
1007 CONFIG_CMD_MISC Misc functions like sleep etc
1008 CONFIG_CMD_MMC * MMC memory mapped support
1009 CONFIG_CMD_MII * MII utility commands
1010 CONFIG_CMD_MTDPARTS * MTD partition support
1011 CONFIG_CMD_NAND * NAND support
1012 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1013 CONFIG_CMD_NFS NFS support
1014 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1015 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1016 CONFIG_CMD_PCI * pciinfo
1017 CONFIG_CMD_PCMCIA * PCMCIA support
1018 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1020 CONFIG_CMD_PORTIO * Port I/O
1021 CONFIG_CMD_READ * Read raw data from partition
1022 CONFIG_CMD_REGINFO * Register dump
1023 CONFIG_CMD_RUN run command in env variable
1024 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1025 CONFIG_CMD_SAVES * save S record dump
1026 CONFIG_CMD_SCSI * SCSI Support
1027 CONFIG_CMD_SDRAM * print SDRAM configuration information
1028 (requires CONFIG_CMD_I2C)
1029 CONFIG_CMD_SETGETDCR Support for DCR Register access
1031 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1032 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1033 (requires CONFIG_CMD_MEMORY)
1034 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1035 CONFIG_CMD_SOURCE "source" command Support
1036 CONFIG_CMD_SPI * SPI serial bus support
1037 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1038 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1039 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1040 CONFIG_CMD_TIMER * access to the system tick timer
1041 CONFIG_CMD_USB * USB support
1042 CONFIG_CMD_CDP * Cisco Discover Protocol support
1043 CONFIG_CMD_MFSL * Microblaze FSL support
1044 CONFIG_CMD_XIMG Load part of Multi Image
1045 CONFIG_CMD_UUID * Generate random UUID or GUID string
1047 EXAMPLE: If you want all functions except of network
1048 support you can write:
1050 #include "config_cmd_all.h"
1051 #undef CONFIG_CMD_NET
1054 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1056 Note: Don't enable the "icache" and "dcache" commands
1057 (configuration option CONFIG_CMD_CACHE) unless you know
1058 what you (and your U-Boot users) are doing. Data
1059 cache cannot be enabled on systems like the 8xx or
1060 8260 (where accesses to the IMMR region must be
1061 uncached), and it cannot be disabled on all other
1062 systems where we (mis-) use the data cache to hold an
1063 initial stack and some data.
1066 XXX - this list needs to get updated!
1068 - Regular expression support:
1070 If this variable is defined, U-Boot is linked against
1071 the SLRE (Super Light Regular Expression) library,
1072 which adds regex support to some commands, as for
1073 example "env grep" and "setexpr".
1077 If this variable is defined, U-Boot will use a device tree
1078 to configure its devices, instead of relying on statically
1079 compiled #defines in the board file. This option is
1080 experimental and only available on a few boards. The device
1081 tree is available in the global data as gd->fdt_blob.
1083 U-Boot needs to get its device tree from somewhere. This can
1084 be done using one of the two options below:
1087 If this variable is defined, U-Boot will embed a device tree
1088 binary in its image. This device tree file should be in the
1089 board directory and called <soc>-<board>.dts. The binary file
1090 is then picked up in board_init_f() and made available through
1091 the global data structure as gd->blob.
1094 If this variable is defined, U-Boot will build a device tree
1095 binary. It will be called u-boot.dtb. Architecture-specific
1096 code will locate it at run-time. Generally this works by:
1098 cat u-boot.bin u-boot.dtb >image.bin
1100 and in fact, U-Boot does this for you, creating a file called
1101 u-boot-dtb.bin which is useful in the common case. You can
1102 still use the individual files if you need something more
1107 If this variable is defined, it enables watchdog
1108 support for the SoC. There must be support in the SoC
1109 specific code for a watchdog. For the 8xx and 8260
1110 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1111 register. When supported for a specific SoC is
1112 available, then no further board specific code should
1113 be needed to use it.
1116 When using a watchdog circuitry external to the used
1117 SoC, then define this variable and provide board
1118 specific code for the "hw_watchdog_reset" function.
1121 CONFIG_VERSION_VARIABLE
1122 If this variable is defined, an environment variable
1123 named "ver" is created by U-Boot showing the U-Boot
1124 version as printed by the "version" command.
1125 Any change to this variable will be reverted at the
1130 When CONFIG_CMD_DATE is selected, the type of the RTC
1131 has to be selected, too. Define exactly one of the
1134 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1135 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1136 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1137 CONFIG_RTC_MC146818 - use MC146818 RTC
1138 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1139 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1140 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1141 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1142 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1143 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1144 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1145 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1148 Note that if the RTC uses I2C, then the I2C interface
1149 must also be configured. See I2C Support, below.
1152 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1154 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1155 chip-ngpio pairs that tell the PCA953X driver the number of
1156 pins supported by a particular chip.
1158 Note that if the GPIO device uses I2C, then the I2C interface
1159 must also be configured. See I2C Support, below.
1161 - Timestamp Support:
1163 When CONFIG_TIMESTAMP is selected, the timestamp
1164 (date and time) of an image is printed by image
1165 commands like bootm or iminfo. This option is
1166 automatically enabled when you select CONFIG_CMD_DATE .
1168 - Partition Labels (disklabels) Supported:
1169 Zero or more of the following:
1170 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1171 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1172 Intel architecture, USB sticks, etc.
1173 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1174 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1175 bootloader. Note 2TB partition limit; see
1177 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1179 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1180 CONFIG_CMD_SCSI) you must configure support for at
1181 least one non-MTD partition type as well.
1184 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1185 board configurations files but used nowhere!
1187 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1188 be performed by calling the function
1189 ide_set_reset(int reset)
1190 which has to be defined in a board specific file
1195 Set this to enable ATAPI support.
1200 Set this to enable support for disks larger than 137GB
1201 Also look at CONFIG_SYS_64BIT_LBA.
1202 Whithout these , LBA48 support uses 32bit variables and will 'only'
1203 support disks up to 2.1TB.
1205 CONFIG_SYS_64BIT_LBA:
1206 When enabled, makes the IDE subsystem use 64bit sector addresses.
1210 At the moment only there is only support for the
1211 SYM53C8XX SCSI controller; define
1212 CONFIG_SCSI_SYM53C8XX to enable it.
1214 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1215 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1216 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1217 maximum numbers of LUNs, SCSI ID's and target
1219 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1221 The environment variable 'scsidevs' is set to the number of
1222 SCSI devices found during the last scan.
1224 - NETWORK Support (PCI):
1226 Support for Intel 8254x/8257x gigabit chips.
1229 Utility code for direct access to the SPI bus on Intel 8257x.
1230 This does not do anything useful unless you set at least one
1231 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1233 CONFIG_E1000_SPI_GENERIC
1234 Allow generic access to the SPI bus on the Intel 8257x, for
1235 example with the "sspi" command.
1238 Management command for E1000 devices. When used on devices
1239 with SPI support you can reprogram the EEPROM from U-Boot.
1241 CONFIG_E1000_FALLBACK_MAC
1242 default MAC for empty EEPROM after production.
1245 Support for Intel 82557/82559/82559ER chips.
1246 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1247 write routine for first time initialisation.
1250 Support for Digital 2114x chips.
1251 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1252 modem chip initialisation (KS8761/QS6611).
1255 Support for National dp83815 chips.
1258 Support for National dp8382[01] gigabit chips.
1260 - NETWORK Support (other):
1262 CONFIG_DRIVER_AT91EMAC
1263 Support for AT91RM9200 EMAC.
1266 Define this to use reduced MII inteface
1268 CONFIG_DRIVER_AT91EMAC_QUIET
1269 If this defined, the driver is quiet.
1270 The driver doen't show link status messages.
1272 CONFIG_CALXEDA_XGMAC
1273 Support for the Calxeda XGMAC device
1276 Support for SMSC's LAN91C96 chips.
1278 CONFIG_LAN91C96_BASE
1279 Define this to hold the physical address
1280 of the LAN91C96's I/O space
1282 CONFIG_LAN91C96_USE_32_BIT
1283 Define this to enable 32 bit addressing
1286 Support for SMSC's LAN91C111 chip
1288 CONFIG_SMC91111_BASE
1289 Define this to hold the physical address
1290 of the device (I/O space)
1292 CONFIG_SMC_USE_32_BIT
1293 Define this if data bus is 32 bits
1295 CONFIG_SMC_USE_IOFUNCS
1296 Define this to use i/o functions instead of macros
1297 (some hardware wont work with macros)
1299 CONFIG_DRIVER_TI_EMAC
1300 Support for davinci emac
1302 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1303 Define this if you have more then 3 PHYs.
1306 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1308 CONFIG_FTGMAC100_EGIGA
1309 Define this to use GE link update with gigabit PHY.
1310 Define this if FTGMAC100 is connected to gigabit PHY.
1311 If your system has 10/100 PHY only, it might not occur
1312 wrong behavior. Because PHY usually return timeout or
1313 useless data when polling gigabit status and gigabit
1314 control registers. This behavior won't affect the
1315 correctnessof 10/100 link speed update.
1318 Support for SMSC's LAN911x and LAN921x chips
1321 Define this to hold the physical address
1322 of the device (I/O space)
1324 CONFIG_SMC911X_32_BIT
1325 Define this if data bus is 32 bits
1327 CONFIG_SMC911X_16_BIT
1328 Define this if data bus is 16 bits. If your processor
1329 automatically converts one 32 bit word to two 16 bit
1330 words you may also try CONFIG_SMC911X_32_BIT.
1333 Support for Renesas on-chip Ethernet controller
1335 CONFIG_SH_ETHER_USE_PORT
1336 Define the number of ports to be used
1338 CONFIG_SH_ETHER_PHY_ADDR
1339 Define the ETH PHY's address
1341 CONFIG_SH_ETHER_CACHE_WRITEBACK
1342 If this option is set, the driver enables cache flush.
1346 Support TPM devices.
1349 Support for i2c bus TPM devices. Only one device
1350 per system is supported at this time.
1352 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1353 Define the the i2c bus number for the TPM device
1355 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1356 Define the TPM's address on the i2c bus
1358 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1359 Define the burst count bytes upper limit
1361 CONFIG_TPM_ATMEL_TWI
1362 Support for Atmel TWI TPM device. Requires I2C support.
1365 Support for generic parallel port TPM devices. Only one device
1366 per system is supported at this time.
1368 CONFIG_TPM_TIS_BASE_ADDRESS
1369 Base address where the generic TPM device is mapped
1370 to. Contemporary x86 systems usually map it at
1374 Add tpm monitor functions.
1375 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1376 provides monitor access to authorized functions.
1379 Define this to enable the TPM support library which provides
1380 functional interfaces to some TPM commands.
1381 Requires support for a TPM device.
1383 CONFIG_TPM_AUTH_SESSIONS
1384 Define this to enable authorized functions in the TPM library.
1385 Requires CONFIG_TPM and CONFIG_SHA1.
1388 At the moment only the UHCI host controller is
1389 supported (PIP405, MIP405, MPC5200); define
1390 CONFIG_USB_UHCI to enable it.
1391 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1392 and define CONFIG_USB_STORAGE to enable the USB
1395 Supported are USB Keyboards and USB Floppy drives
1397 MPC5200 USB requires additional defines:
1399 for 528 MHz Clock: 0x0001bbbb
1403 for differential drivers: 0x00001000
1404 for single ended drivers: 0x00005000
1405 for differential drivers on PSC3: 0x00000100
1406 for single ended drivers on PSC3: 0x00004100
1407 CONFIG_SYS_USB_EVENT_POLL
1408 May be defined to allow interrupt polling
1409 instead of using asynchronous interrupts
1411 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1412 txfilltuning field in the EHCI controller on reset.
1414 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1415 interval for usb hub power-on delay.(minimum 100msec)
1418 Define the below if you wish to use the USB console.
1419 Once firmware is rebuilt from a serial console issue the
1420 command "setenv stdin usbtty; setenv stdout usbtty" and
1421 attach your USB cable. The Unix command "dmesg" should print
1422 it has found a new device. The environment variable usbtty
1423 can be set to gserial or cdc_acm to enable your device to
1424 appear to a USB host as a Linux gserial device or a
1425 Common Device Class Abstract Control Model serial device.
1426 If you select usbtty = gserial you should be able to enumerate
1428 # modprobe usbserial vendor=0xVendorID product=0xProductID
1429 else if using cdc_acm, simply setting the environment
1430 variable usbtty to be cdc_acm should suffice. The following
1431 might be defined in YourBoardName.h
1434 Define this to build a UDC device
1437 Define this to have a tty type of device available to
1438 talk to the UDC device
1441 Define this to enable the high speed support for usb
1442 device and usbtty. If this feature is enabled, a routine
1443 int is_usbd_high_speed(void)
1444 also needs to be defined by the driver to dynamically poll
1445 whether the enumeration has succeded at high speed or full
1448 CONFIG_SYS_CONSOLE_IS_IN_ENV
1449 Define this if you want stdin, stdout &/or stderr to
1453 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1454 Derive USB clock from external clock "blah"
1455 - CONFIG_SYS_USB_EXTC_CLK 0x02
1457 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1458 Derive USB clock from brgclk
1459 - CONFIG_SYS_USB_BRG_CLK 0x04
1461 If you have a USB-IF assigned VendorID then you may wish to
1462 define your own vendor specific values either in BoardName.h
1463 or directly in usbd_vendor_info.h. If you don't define
1464 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1465 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1466 should pretend to be a Linux device to it's target host.
1468 CONFIG_USBD_MANUFACTURER
1469 Define this string as the name of your company for
1470 - CONFIG_USBD_MANUFACTURER "my company"
1472 CONFIG_USBD_PRODUCT_NAME
1473 Define this string as the name of your product
1474 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1476 CONFIG_USBD_VENDORID
1477 Define this as your assigned Vendor ID from the USB
1478 Implementors Forum. This *must* be a genuine Vendor ID
1479 to avoid polluting the USB namespace.
1480 - CONFIG_USBD_VENDORID 0xFFFF
1482 CONFIG_USBD_PRODUCTID
1483 Define this as the unique Product ID
1485 - CONFIG_USBD_PRODUCTID 0xFFFF
1487 - ULPI Layer Support:
1488 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1489 the generic ULPI layer. The generic layer accesses the ULPI PHY
1490 via the platform viewport, so you need both the genric layer and
1491 the viewport enabled. Currently only Chipidea/ARC based
1492 viewport is supported.
1493 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1494 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1495 If your ULPI phy needs a different reference clock than the
1496 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1497 the appropriate value in Hz.
1500 The MMC controller on the Intel PXA is supported. To
1501 enable this define CONFIG_MMC. The MMC can be
1502 accessed from the boot prompt by mapping the device
1503 to physical memory similar to flash. Command line is
1504 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1505 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1508 Support for Renesas on-chip MMCIF controller
1510 CONFIG_SH_MMCIF_ADDR
1511 Define the base address of MMCIF registers
1514 Define the clock frequency for MMCIF
1516 - USB Device Firmware Update (DFU) class support:
1518 This enables the USB portion of the DFU USB class
1521 This enables the command "dfu" which is used to have
1522 U-Boot create a DFU class device via USB. This command
1523 requires that the "dfu_alt_info" environment variable be
1524 set and define the alt settings to expose to the host.
1527 This enables support for exposing (e)MMC devices via DFU.
1530 This enables support for exposing NAND devices via DFU.
1533 This enables support for exposing RAM via DFU.
1534 Note: DFU spec refer to non-volatile memory usage, but
1535 allow usages beyond the scope of spec - here RAM usage,
1536 one that would help mostly the developer.
1538 CONFIG_SYS_DFU_DATA_BUF_SIZE
1539 Dfu transfer uses a buffer before writing data to the
1540 raw storage device. Make the size (in bytes) of this buffer
1541 configurable. The size of this buffer is also configurable
1542 through the "dfu_bufsiz" environment variable.
1544 CONFIG_SYS_DFU_MAX_FILE_SIZE
1545 When updating files rather than the raw storage device,
1546 we use a static buffer to copy the file into and then write
1547 the buffer once we've been given the whole file. Define
1548 this to the maximum filesize (in bytes) for the buffer.
1549 Default is 4 MiB if undefined.
1551 DFU_DEFAULT_POLL_TIMEOUT
1552 Poll timeout [ms], is the timeout a device can send to the
1553 host. The host must wait for this timeout before sending
1554 a subsequent DFU_GET_STATUS request to the device.
1556 DFU_MANIFEST_POLL_TIMEOUT
1557 Poll timeout [ms], which the device sends to the host when
1558 entering dfuMANIFEST state. Host waits this timeout, before
1559 sending again an USB request to the device.
1561 - Journaling Flash filesystem support:
1562 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1563 CONFIG_JFFS2_NAND_DEV
1564 Define these for a default partition on a NAND device
1566 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1567 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1568 Define these for a default partition on a NOR device
1570 CONFIG_SYS_JFFS_CUSTOM_PART
1571 Define this to create an own partition. You have to provide a
1572 function struct part_info* jffs2_part_info(int part_num)
1574 If you define only one JFFS2 partition you may also want to
1575 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1576 to disable the command chpart. This is the default when you
1577 have not defined a custom partition
1579 - FAT(File Allocation Table) filesystem write function support:
1582 Define this to enable support for saving memory data as a
1583 file in FAT formatted partition.
1585 This will also enable the command "fatwrite" enabling the
1586 user to write files to FAT.
1588 CBFS (Coreboot Filesystem) support
1591 Define this to enable support for reading from a Coreboot
1592 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1598 Define this to enable standard (PC-Style) keyboard
1602 Standard PC keyboard driver with US (is default) and
1603 GERMAN key layout (switch via environment 'keymap=de') support.
1604 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1605 for cfb_console. Supports cursor blinking.
1608 Enables a Chrome OS keyboard using the CROS_EC interface.
1609 This uses CROS_EC to communicate with a second microcontroller
1610 which provides key scans on request.
1615 Define this to enable video support (for output to
1618 CONFIG_VIDEO_CT69000
1620 Enable Chips & Technologies 69000 Video chip
1622 CONFIG_VIDEO_SMI_LYNXEM
1623 Enable Silicon Motion SMI 712/710/810 Video chip. The
1624 video output is selected via environment 'videoout'
1625 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1628 For the CT69000 and SMI_LYNXEM drivers, videomode is
1629 selected via environment 'videomode'. Two different ways
1631 - "videomode=num" 'num' is a standard LiLo mode numbers.
1632 Following standard modes are supported (* is default):
1634 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1635 -------------+---------------------------------------------
1636 8 bits | 0x301* 0x303 0x305 0x161 0x307
1637 15 bits | 0x310 0x313 0x316 0x162 0x319
1638 16 bits | 0x311 0x314 0x317 0x163 0x31A
1639 24 bits | 0x312 0x315 0x318 ? 0x31B
1640 -------------+---------------------------------------------
1641 (i.e. setenv videomode 317; saveenv; reset;)
1643 - "videomode=bootargs" all the video parameters are parsed
1644 from the bootargs. (See drivers/video/videomodes.c)
1647 CONFIG_VIDEO_SED13806
1648 Enable Epson SED13806 driver. This driver supports 8bpp
1649 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1650 or CONFIG_VIDEO_SED13806_16BPP
1653 Enable the Freescale DIU video driver. Reference boards for
1654 SOCs that have a DIU should define this macro to enable DIU
1655 support, and should also define these other macros:
1661 CONFIG_VIDEO_SW_CURSOR
1662 CONFIG_VGA_AS_SINGLE_DEVICE
1664 CONFIG_VIDEO_BMP_LOGO
1666 The DIU driver will look for the 'video-mode' environment
1667 variable, and if defined, enable the DIU as a console during
1668 boot. See the documentation file README.video for a
1669 description of this variable.
1673 Enable the VGA video / BIOS for x86. The alternative if you
1674 are using coreboot is to use the coreboot frame buffer
1681 Define this to enable a custom keyboard support.
1682 This simply calls drv_keyboard_init() which must be
1683 defined in your board-specific files.
1684 The only board using this so far is RBC823.
1686 - LCD Support: CONFIG_LCD
1688 Define this to enable LCD support (for output to LCD
1689 display); also select one of the supported displays
1690 by defining one of these:
1694 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1696 CONFIG_NEC_NL6448AC33:
1698 NEC NL6448AC33-18. Active, color, single scan.
1700 CONFIG_NEC_NL6448BC20
1702 NEC NL6448BC20-08. 6.5", 640x480.
1703 Active, color, single scan.
1705 CONFIG_NEC_NL6448BC33_54
1707 NEC NL6448BC33-54. 10.4", 640x480.
1708 Active, color, single scan.
1712 Sharp 320x240. Active, color, single scan.
1713 It isn't 16x9, and I am not sure what it is.
1715 CONFIG_SHARP_LQ64D341
1717 Sharp LQ64D341 display, 640x480.
1718 Active, color, single scan.
1722 HLD1045 display, 640x480.
1723 Active, color, single scan.
1727 Optrex CBL50840-2 NF-FW 99 22 M5
1729 Hitachi LMG6912RPFC-00T
1733 320x240. Black & white.
1735 Normally display is black on white background; define
1736 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1738 CONFIG_LCD_ALIGNMENT
1740 Normally the LCD is page-aligned (tyically 4KB). If this is
1741 defined then the LCD will be aligned to this value instead.
1742 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1743 here, since it is cheaper to change data cache settings on
1744 a per-section basis.
1746 CONFIG_CONSOLE_SCROLL_LINES
1748 When the console need to be scrolled, this is the number of
1749 lines to scroll by. It defaults to 1. Increasing this makes
1750 the console jump but can help speed up operation when scrolling
1755 Support drawing of RLE8-compressed bitmaps on the LCD.
1759 Enables an 'i2c edid' command which can read EDID
1760 information over I2C from an attached LCD display.
1762 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1764 If this option is set, the environment is checked for
1765 a variable "splashimage". If found, the usual display
1766 of logo, copyright and system information on the LCD
1767 is suppressed and the BMP image at the address
1768 specified in "splashimage" is loaded instead. The
1769 console is redirected to the "nulldev", too. This
1770 allows for a "silent" boot where a splash screen is
1771 loaded very quickly after power-on.
1773 CONFIG_SPLASHIMAGE_GUARD
1775 If this option is set, then U-Boot will prevent the environment
1776 variable "splashimage" from being set to a problematic address
1777 (see README.displaying-bmps).
1778 This option is useful for targets where, due to alignment
1779 restrictions, an improperly aligned BMP image will cause a data
1780 abort. If you think you will not have problems with unaligned
1781 accesses (for example because your toolchain prevents them)
1782 there is no need to set this option.
1784 CONFIG_SPLASH_SCREEN_ALIGN
1786 If this option is set the splash image can be freely positioned
1787 on the screen. Environment variable "splashpos" specifies the
1788 position as "x,y". If a positive number is given it is used as
1789 number of pixel from left/top. If a negative number is given it
1790 is used as number of pixel from right/bottom. You can also
1791 specify 'm' for centering the image.
1794 setenv splashpos m,m
1795 => image at center of screen
1797 setenv splashpos 30,20
1798 => image at x = 30 and y = 20
1800 setenv splashpos -10,m
1801 => vertically centered image
1802 at x = dspWidth - bmpWidth - 9
1804 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1806 If this option is set, additionally to standard BMP
1807 images, gzipped BMP images can be displayed via the
1808 splashscreen support or the bmp command.
1810 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1812 If this option is set, 8-bit RLE compressed BMP images
1813 can be displayed via the splashscreen support or the
1816 - Do compresssing for memory range:
1819 If this option is set, it would use zlib deflate method
1820 to compress the specified memory at its best effort.
1822 - Compression support:
1825 Enabled by default to support gzip compressed images.
1829 If this option is set, support for bzip2 compressed
1830 images is included. If not, only uncompressed and gzip
1831 compressed images are supported.
1833 NOTE: the bzip2 algorithm requires a lot of RAM, so
1834 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1839 If this option is set, support for lzma compressed
1842 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1843 requires an amount of dynamic memory that is given by the
1846 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1848 Where lc and lp stand for, respectively, Literal context bits
1849 and Literal pos bits.
1851 This value is upper-bounded by 14MB in the worst case. Anyway,
1852 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1853 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1854 a very small buffer.
1856 Use the lzmainfo tool to determinate the lc and lp values and
1857 then calculate the amount of needed dynamic memory (ensuring
1858 the appropriate CONFIG_SYS_MALLOC_LEN value).
1862 If this option is set, support for LZO compressed images
1868 The address of PHY on MII bus.
1870 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1872 The clock frequency of the MII bus
1876 If this option is set, support for speed/duplex
1877 detection of gigabit PHY is included.
1879 CONFIG_PHY_RESET_DELAY
1881 Some PHY like Intel LXT971A need extra delay after
1882 reset before any MII register access is possible.
1883 For such PHY, set this option to the usec delay
1884 required. (minimum 300usec for LXT971A)
1886 CONFIG_PHY_CMD_DELAY (ppc4xx)
1888 Some PHY like Intel LXT971A need extra delay after
1889 command issued before MII status register can be read
1899 Define a default value for Ethernet address to use
1900 for the respective Ethernet interface, in case this
1901 is not determined automatically.
1906 Define a default value for the IP address to use for
1907 the default Ethernet interface, in case this is not
1908 determined through e.g. bootp.
1909 (Environment variable "ipaddr")
1911 - Server IP address:
1914 Defines a default value for the IP address of a TFTP
1915 server to contact when using the "tftboot" command.
1916 (Environment variable "serverip")
1918 CONFIG_KEEP_SERVERADDR
1920 Keeps the server's MAC address, in the env 'serveraddr'
1921 for passing to bootargs (like Linux's netconsole option)
1923 - Gateway IP address:
1926 Defines a default value for the IP address of the
1927 default router where packets to other networks are
1929 (Environment variable "gatewayip")
1934 Defines a default value for the subnet mask (or
1935 routing prefix) which is used to determine if an IP
1936 address belongs to the local subnet or needs to be
1937 forwarded through a router.
1938 (Environment variable "netmask")
1940 - Multicast TFTP Mode:
1943 Defines whether you want to support multicast TFTP as per
1944 rfc-2090; for example to work with atftp. Lets lots of targets
1945 tftp down the same boot image concurrently. Note: the Ethernet
1946 driver in use must provide a function: mcast() to join/leave a
1949 - BOOTP Recovery Mode:
1950 CONFIG_BOOTP_RANDOM_DELAY
1952 If you have many targets in a network that try to
1953 boot using BOOTP, you may want to avoid that all
1954 systems send out BOOTP requests at precisely the same
1955 moment (which would happen for instance at recovery
1956 from a power failure, when all systems will try to
1957 boot, thus flooding the BOOTP server. Defining
1958 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1959 inserted before sending out BOOTP requests. The
1960 following delays are inserted then:
1962 1st BOOTP request: delay 0 ... 1 sec
1963 2nd BOOTP request: delay 0 ... 2 sec
1964 3rd BOOTP request: delay 0 ... 4 sec
1966 BOOTP requests: delay 0 ... 8 sec
1968 - DHCP Advanced Options:
1969 You can fine tune the DHCP functionality by defining
1970 CONFIG_BOOTP_* symbols:
1972 CONFIG_BOOTP_SUBNETMASK
1973 CONFIG_BOOTP_GATEWAY
1974 CONFIG_BOOTP_HOSTNAME
1975 CONFIG_BOOTP_NISDOMAIN
1976 CONFIG_BOOTP_BOOTPATH
1977 CONFIG_BOOTP_BOOTFILESIZE
1980 CONFIG_BOOTP_SEND_HOSTNAME
1981 CONFIG_BOOTP_NTPSERVER
1982 CONFIG_BOOTP_TIMEOFFSET
1983 CONFIG_BOOTP_VENDOREX
1984 CONFIG_BOOTP_MAY_FAIL
1986 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1987 environment variable, not the BOOTP server.
1989 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1990 after the configured retry count, the call will fail
1991 instead of starting over. This can be used to fail over
1992 to Link-local IP address configuration if the DHCP server
1995 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1996 serverip from a DHCP server, it is possible that more
1997 than one DNS serverip is offered to the client.
1998 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1999 serverip will be stored in the additional environment
2000 variable "dnsip2". The first DNS serverip is always
2001 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2004 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2005 to do a dynamic update of a DNS server. To do this, they
2006 need the hostname of the DHCP requester.
2007 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2008 of the "hostname" environment variable is passed as
2009 option 12 to the DHCP server.
2011 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2013 A 32bit value in microseconds for a delay between
2014 receiving a "DHCP Offer" and sending the "DHCP Request".
2015 This fixes a problem with certain DHCP servers that don't
2016 respond 100% of the time to a "DHCP request". E.g. On an
2017 AT91RM9200 processor running at 180MHz, this delay needed
2018 to be *at least* 15,000 usec before a Windows Server 2003
2019 DHCP server would reply 100% of the time. I recommend at
2020 least 50,000 usec to be safe. The alternative is to hope
2021 that one of the retries will be successful but note that
2022 the DHCP timeout and retry process takes a longer than
2025 - Link-local IP address negotiation:
2026 Negotiate with other link-local clients on the local network
2027 for an address that doesn't require explicit configuration.
2028 This is especially useful if a DHCP server cannot be guaranteed
2029 to exist in all environments that the device must operate.
2031 See doc/README.link-local for more information.
2034 CONFIG_CDP_DEVICE_ID
2036 The device id used in CDP trigger frames.
2038 CONFIG_CDP_DEVICE_ID_PREFIX
2040 A two character string which is prefixed to the MAC address
2045 A printf format string which contains the ascii name of
2046 the port. Normally is set to "eth%d" which sets
2047 eth0 for the first Ethernet, eth1 for the second etc.
2049 CONFIG_CDP_CAPABILITIES
2051 A 32bit integer which indicates the device capabilities;
2052 0x00000010 for a normal host which does not forwards.
2056 An ascii string containing the version of the software.
2060 An ascii string containing the name of the platform.
2064 A 32bit integer sent on the trigger.
2066 CONFIG_CDP_POWER_CONSUMPTION
2068 A 16bit integer containing the power consumption of the
2069 device in .1 of milliwatts.
2071 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2073 A byte containing the id of the VLAN.
2075 - Status LED: CONFIG_STATUS_LED
2077 Several configurations allow to display the current
2078 status using a LED. For instance, the LED will blink
2079 fast while running U-Boot code, stop blinking as
2080 soon as a reply to a BOOTP request was received, and
2081 start blinking slow once the Linux kernel is running
2082 (supported by a status LED driver in the Linux
2083 kernel). Defining CONFIG_STATUS_LED enables this
2089 The status LED can be connected to a GPIO pin.
2090 In such cases, the gpio_led driver can be used as a
2091 status LED backend implementation. Define CONFIG_GPIO_LED
2092 to include the gpio_led driver in the U-Boot binary.
2094 CONFIG_GPIO_LED_INVERTED_TABLE
2095 Some GPIO connected LEDs may have inverted polarity in which
2096 case the GPIO high value corresponds to LED off state and
2097 GPIO low value corresponds to LED on state.
2098 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2099 with a list of GPIO LEDs that have inverted polarity.
2101 - CAN Support: CONFIG_CAN_DRIVER
2103 Defining CONFIG_CAN_DRIVER enables CAN driver support
2104 on those systems that support this (optional)
2105 feature, like the TQM8xxL modules.
2107 - I2C Support: CONFIG_SYS_I2C
2109 This enable the NEW i2c subsystem, and will allow you to use
2110 i2c commands at the u-boot command line (as long as you set
2111 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2112 based realtime clock chips or other i2c devices. See
2113 common/cmd_i2c.c for a description of the command line
2116 ported i2c driver to the new framework:
2117 - drivers/i2c/soft_i2c.c:
2118 - activate first bus with CONFIG_SYS_I2C_SOFT define
2119 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2120 for defining speed and slave address
2121 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2122 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2123 for defining speed and slave address
2124 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2125 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2126 for defining speed and slave address
2127 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2128 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2129 for defining speed and slave address
2131 - drivers/i2c/fsl_i2c.c:
2132 - activate i2c driver with CONFIG_SYS_I2C_FSL
2133 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2134 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2135 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2137 - If your board supports a second fsl i2c bus, define
2138 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2139 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2140 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2143 - drivers/i2c/tegra_i2c.c:
2144 - activate this driver with CONFIG_SYS_I2C_TEGRA
2145 - This driver adds 4 i2c buses with a fix speed from
2146 100000 and the slave addr 0!
2148 - drivers/i2c/ppc4xx_i2c.c
2149 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2150 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2151 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2153 - drivers/i2c/i2c_mxc.c
2154 - activate this driver with CONFIG_SYS_I2C_MXC
2155 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2156 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2157 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2158 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2159 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2160 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2161 If thoses defines are not set, default value is 100000
2162 for speed, and 0 for slave.
2164 - drivers/i2c/rcar_i2c.c:
2165 - activate this driver with CONFIG_SYS_I2C_RCAR
2166 - This driver adds 4 i2c buses
2168 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2169 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2170 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2171 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2172 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2173 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2174 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2175 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2176 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2178 - drivers/i2c/sh_i2c.c:
2179 - activate this driver with CONFIG_SYS_I2C_SH
2180 - This driver adds from 2 to 5 i2c buses
2182 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2183 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2184 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2185 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2186 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2187 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2188 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2189 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2190 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2191 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2192 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2193 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2194 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2196 - drivers/i2c/omap24xx_i2c.c
2197 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2198 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2199 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2200 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2201 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2202 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2203 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2204 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2205 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2206 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2207 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2209 - drivers/i2c/zynq_i2c.c
2210 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2211 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2212 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2214 - drivers/i2c/s3c24x0_i2c.c:
2215 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2216 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2217 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2218 with a fix speed from 100000 and the slave addr 0!
2222 CONFIG_SYS_NUM_I2C_BUSES
2223 Hold the number of i2c busses you want to use. If you
2224 don't use/have i2c muxes on your i2c bus, this
2225 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2228 CONFIG_SYS_I2C_DIRECT_BUS
2229 define this, if you don't use i2c muxes on your hardware.
2230 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2233 CONFIG_SYS_I2C_MAX_HOPS
2234 define how many muxes are maximal consecutively connected
2235 on one i2c bus. If you not use i2c muxes, omit this
2238 CONFIG_SYS_I2C_BUSES
2239 hold a list of busses you want to use, only used if
2240 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2241 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2242 CONFIG_SYS_NUM_I2C_BUSES = 9:
2244 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2245 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2246 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2247 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2248 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2249 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2250 {1, {I2C_NULL_HOP}}, \
2251 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2252 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2256 bus 0 on adapter 0 without a mux
2257 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2258 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2259 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2260 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2261 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2262 bus 6 on adapter 1 without a mux
2263 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2264 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2266 If you do not have i2c muxes on your board, omit this define.
2268 - Legacy I2C Support: CONFIG_HARD_I2C
2270 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2271 provides the following compelling advantages:
2273 - more than one i2c adapter is usable
2274 - approved multibus support
2275 - better i2c mux support
2277 ** Please consider updating your I2C driver now. **
2279 These enable legacy I2C serial bus commands. Defining
2280 CONFIG_HARD_I2C will include the appropriate I2C driver
2281 for the selected CPU.
2283 This will allow you to use i2c commands at the u-boot
2284 command line (as long as you set CONFIG_CMD_I2C in
2285 CONFIG_COMMANDS) and communicate with i2c based realtime
2286 clock chips. See common/cmd_i2c.c for a description of the
2287 command line interface.
2289 CONFIG_HARD_I2C selects a hardware I2C controller.
2291 There are several other quantities that must also be
2292 defined when you define CONFIG_HARD_I2C.
2294 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2295 to be the frequency (in Hz) at which you wish your i2c bus
2296 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2297 the CPU's i2c node address).
2299 Now, the u-boot i2c code for the mpc8xx
2300 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2301 and so its address should therefore be cleared to 0 (See,
2302 eg, MPC823e User's Manual p.16-473). So, set
2303 CONFIG_SYS_I2C_SLAVE to 0.
2305 CONFIG_SYS_I2C_INIT_MPC5XXX
2307 When a board is reset during an i2c bus transfer
2308 chips might think that the current transfer is still
2309 in progress. Reset the slave devices by sending start
2310 commands until the slave device responds.
2312 That's all that's required for CONFIG_HARD_I2C.
2314 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2315 then the following macros need to be defined (examples are
2316 from include/configs/lwmon.h):
2320 (Optional). Any commands necessary to enable the I2C
2321 controller or configure ports.
2323 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2327 (Only for MPC8260 CPU). The I/O port to use (the code
2328 assumes both bits are on the same port). Valid values
2329 are 0..3 for ports A..D.
2333 The code necessary to make the I2C data line active
2334 (driven). If the data line is open collector, this
2337 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2341 The code necessary to make the I2C data line tri-stated
2342 (inactive). If the data line is open collector, this
2345 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2349 Code that returns true if the I2C data line is high,
2352 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2356 If <bit> is true, sets the I2C data line high. If it
2357 is false, it clears it (low).
2359 eg: #define I2C_SDA(bit) \
2360 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2361 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2365 If <bit> is true, sets the I2C clock line high. If it
2366 is false, it clears it (low).
2368 eg: #define I2C_SCL(bit) \
2369 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2370 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2374 This delay is invoked four times per clock cycle so this
2375 controls the rate of data transfer. The data rate thus
2376 is 1 / (I2C_DELAY * 4). Often defined to be something
2379 #define I2C_DELAY udelay(2)
2381 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2383 If your arch supports the generic GPIO framework (asm/gpio.h),
2384 then you may alternatively define the two GPIOs that are to be
2385 used as SCL / SDA. Any of the previous I2C_xxx macros will
2386 have GPIO-based defaults assigned to them as appropriate.
2388 You should define these to the GPIO value as given directly to
2389 the generic GPIO functions.
2391 CONFIG_SYS_I2C_INIT_BOARD
2393 When a board is reset during an i2c bus transfer
2394 chips might think that the current transfer is still
2395 in progress. On some boards it is possible to access
2396 the i2c SCLK line directly, either by using the
2397 processor pin as a GPIO or by having a second pin
2398 connected to the bus. If this option is defined a
2399 custom i2c_init_board() routine in boards/xxx/board.c
2400 is run early in the boot sequence.
2402 CONFIG_SYS_I2C_BOARD_LATE_INIT
2404 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2405 defined a custom i2c_board_late_init() routine in
2406 boards/xxx/board.c is run AFTER the operations in i2c_init()
2407 is completed. This callpoint can be used to unreset i2c bus
2408 using CPU i2c controller register accesses for CPUs whose i2c
2409 controller provide such a method. It is called at the end of
2410 i2c_init() to allow i2c_init operations to setup the i2c bus
2411 controller on the CPU (e.g. setting bus speed & slave address).
2413 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2415 This option enables configuration of bi_iic_fast[] flags
2416 in u-boot bd_info structure based on u-boot environment
2417 variable "i2cfast". (see also i2cfast)
2419 CONFIG_I2C_MULTI_BUS
2421 This option allows the use of multiple I2C buses, each of which
2422 must have a controller. At any point in time, only one bus is
2423 active. To switch to a different bus, use the 'i2c dev' command.
2424 Note that bus numbering is zero-based.
2426 CONFIG_SYS_I2C_NOPROBES
2428 This option specifies a list of I2C devices that will be skipped
2429 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2430 is set, specify a list of bus-device pairs. Otherwise, specify
2431 a 1D array of device addresses
2434 #undef CONFIG_I2C_MULTI_BUS
2435 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2437 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2439 #define CONFIG_I2C_MULTI_BUS
2440 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2442 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2444 CONFIG_SYS_SPD_BUS_NUM
2446 If defined, then this indicates the I2C bus number for DDR SPD.
2447 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2449 CONFIG_SYS_RTC_BUS_NUM
2451 If defined, then this indicates the I2C bus number for the RTC.
2452 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2454 CONFIG_SYS_DTT_BUS_NUM
2456 If defined, then this indicates the I2C bus number for the DTT.
2457 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2459 CONFIG_SYS_I2C_DTT_ADDR:
2461 If defined, specifies the I2C address of the DTT device.
2462 If not defined, then U-Boot uses predefined value for
2463 specified DTT device.
2465 CONFIG_SOFT_I2C_READ_REPEATED_START
2467 defining this will force the i2c_read() function in
2468 the soft_i2c driver to perform an I2C repeated start
2469 between writing the address pointer and reading the
2470 data. If this define is omitted the default behaviour
2471 of doing a stop-start sequence will be used. Most I2C
2472 devices can use either method, but some require one or
2475 - SPI Support: CONFIG_SPI
2477 Enables SPI driver (so far only tested with
2478 SPI EEPROM, also an instance works with Crystal A/D and
2479 D/As on the SACSng board)
2483 Enables the driver for SPI controller on SuperH. Currently
2484 only SH7757 is supported.
2488 Enables extended (16-bit) SPI EEPROM addressing.
2489 (symmetrical to CONFIG_I2C_X)
2493 Enables a software (bit-bang) SPI driver rather than
2494 using hardware support. This is a general purpose
2495 driver that only requires three general I/O port pins
2496 (two outputs, one input) to function. If this is
2497 defined, the board configuration must define several
2498 SPI configuration items (port pins to use, etc). For
2499 an example, see include/configs/sacsng.h.
2503 Enables a hardware SPI driver for general-purpose reads
2504 and writes. As with CONFIG_SOFT_SPI, the board configuration
2505 must define a list of chip-select function pointers.
2506 Currently supported on some MPC8xxx processors. For an
2507 example, see include/configs/mpc8349emds.h.
2511 Enables the driver for the SPI controllers on i.MX and MXC
2512 SoCs. Currently i.MX31/35/51 are supported.
2514 - FPGA Support: CONFIG_FPGA
2516 Enables FPGA subsystem.
2518 CONFIG_FPGA_<vendor>
2520 Enables support for specific chip vendors.
2523 CONFIG_FPGA_<family>
2525 Enables support for FPGA family.
2526 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2530 Specify the number of FPGA devices to support.
2532 CONFIG_SYS_FPGA_PROG_FEEDBACK
2534 Enable printing of hash marks during FPGA configuration.
2536 CONFIG_SYS_FPGA_CHECK_BUSY
2538 Enable checks on FPGA configuration interface busy
2539 status by the configuration function. This option
2540 will require a board or device specific function to
2545 If defined, a function that provides delays in the FPGA
2546 configuration driver.
2548 CONFIG_SYS_FPGA_CHECK_CTRLC
2549 Allow Control-C to interrupt FPGA configuration
2551 CONFIG_SYS_FPGA_CHECK_ERROR
2553 Check for configuration errors during FPGA bitfile
2554 loading. For example, abort during Virtex II
2555 configuration if the INIT_B line goes low (which
2556 indicated a CRC error).
2558 CONFIG_SYS_FPGA_WAIT_INIT
2560 Maximum time to wait for the INIT_B line to deassert
2561 after PROB_B has been deasserted during a Virtex II
2562 FPGA configuration sequence. The default time is 500
2565 CONFIG_SYS_FPGA_WAIT_BUSY
2567 Maximum time to wait for BUSY to deassert during
2568 Virtex II FPGA configuration. The default is 5 ms.
2570 CONFIG_SYS_FPGA_WAIT_CONFIG
2572 Time to wait after FPGA configuration. The default is
2575 - Configuration Management:
2578 If defined, this string will be added to the U-Boot
2579 version information (U_BOOT_VERSION)
2581 - Vendor Parameter Protection:
2583 U-Boot considers the values of the environment
2584 variables "serial#" (Board Serial Number) and
2585 "ethaddr" (Ethernet Address) to be parameters that
2586 are set once by the board vendor / manufacturer, and
2587 protects these variables from casual modification by
2588 the user. Once set, these variables are read-only,
2589 and write or delete attempts are rejected. You can
2590 change this behaviour:
2592 If CONFIG_ENV_OVERWRITE is #defined in your config
2593 file, the write protection for vendor parameters is
2594 completely disabled. Anybody can change or delete
2597 Alternatively, if you #define _both_ CONFIG_ETHADDR
2598 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2599 Ethernet address is installed in the environment,
2600 which can be changed exactly ONCE by the user. [The
2601 serial# is unaffected by this, i. e. it remains
2604 The same can be accomplished in a more flexible way
2605 for any variable by configuring the type of access
2606 to allow for those variables in the ".flags" variable
2607 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2612 Define this variable to enable the reservation of
2613 "protected RAM", i. e. RAM which is not overwritten
2614 by U-Boot. Define CONFIG_PRAM to hold the number of
2615 kB you want to reserve for pRAM. You can overwrite
2616 this default value by defining an environment
2617 variable "pram" to the number of kB you want to
2618 reserve. Note that the board info structure will
2619 still show the full amount of RAM. If pRAM is
2620 reserved, a new environment variable "mem" will
2621 automatically be defined to hold the amount of
2622 remaining RAM in a form that can be passed as boot
2623 argument to Linux, for instance like that:
2625 setenv bootargs ... mem=\${mem}
2628 This way you can tell Linux not to use this memory,
2629 either, which results in a memory region that will
2630 not be affected by reboots.
2632 *WARNING* If your board configuration uses automatic
2633 detection of the RAM size, you must make sure that
2634 this memory test is non-destructive. So far, the
2635 following board configurations are known to be
2638 IVMS8, IVML24, SPD8xx, TQM8xxL,
2639 HERMES, IP860, RPXlite, LWMON,
2642 - Access to physical memory region (> 4GB)
2643 Some basic support is provided for operations on memory not
2644 normally accessible to U-Boot - e.g. some architectures
2645 support access to more than 4GB of memory on 32-bit
2646 machines using physical address extension or similar.
2647 Define CONFIG_PHYSMEM to access this basic support, which
2648 currently only supports clearing the memory.
2653 Define this variable to stop the system in case of a
2654 fatal error, so that you have to reset it manually.
2655 This is probably NOT a good idea for an embedded
2656 system where you want the system to reboot
2657 automatically as fast as possible, but it may be
2658 useful during development since you can try to debug
2659 the conditions that lead to the situation.
2661 CONFIG_NET_RETRY_COUNT
2663 This variable defines the number of retries for
2664 network operations like ARP, RARP, TFTP, or BOOTP
2665 before giving up the operation. If not defined, a
2666 default value of 5 is used.
2670 Timeout waiting for an ARP reply in milliseconds.
2674 Timeout in milliseconds used in NFS protocol.
2675 If you encounter "ERROR: Cannot umount" in nfs command,
2676 try longer timeout such as
2677 #define CONFIG_NFS_TIMEOUT 10000UL
2679 - Command Interpreter:
2680 CONFIG_AUTO_COMPLETE
2682 Enable auto completion of commands using TAB.
2684 Note that this feature has NOT been implemented yet
2685 for the "hush" shell.
2688 CONFIG_SYS_HUSH_PARSER
2690 Define this variable to enable the "hush" shell (from
2691 Busybox) as command line interpreter, thus enabling
2692 powerful command line syntax like
2693 if...then...else...fi conditionals or `&&' and '||'
2694 constructs ("shell scripts").
2696 If undefined, you get the old, much simpler behaviour
2697 with a somewhat smaller memory footprint.
2700 CONFIG_SYS_PROMPT_HUSH_PS2
2702 This defines the secondary prompt string, which is
2703 printed when the command interpreter needs more input
2704 to complete a command. Usually "> ".
2708 In the current implementation, the local variables
2709 space and global environment variables space are
2710 separated. Local variables are those you define by
2711 simply typing `name=value'. To access a local
2712 variable later on, you have write `$name' or
2713 `${name}'; to execute the contents of a variable
2714 directly type `$name' at the command prompt.
2716 Global environment variables are those you use
2717 setenv/printenv to work with. To run a command stored
2718 in such a variable, you need to use the run command,
2719 and you must not use the '$' sign to access them.
2721 To store commands and special characters in a
2722 variable, please use double quotation marks
2723 surrounding the whole text of the variable, instead
2724 of the backslashes before semicolons and special
2727 - Commandline Editing and History:
2728 CONFIG_CMDLINE_EDITING
2730 Enable editing and History functions for interactive
2731 commandline input operations
2733 - Default Environment:
2734 CONFIG_EXTRA_ENV_SETTINGS
2736 Define this to contain any number of null terminated
2737 strings (variable = value pairs) that will be part of
2738 the default environment compiled into the boot image.
2740 For example, place something like this in your
2741 board's config file:
2743 #define CONFIG_EXTRA_ENV_SETTINGS \
2747 Warning: This method is based on knowledge about the
2748 internal format how the environment is stored by the
2749 U-Boot code. This is NOT an official, exported
2750 interface! Although it is unlikely that this format
2751 will change soon, there is no guarantee either.
2752 You better know what you are doing here.
2754 Note: overly (ab)use of the default environment is
2755 discouraged. Make sure to check other ways to preset
2756 the environment like the "source" command or the
2759 CONFIG_ENV_VARS_UBOOT_CONFIG
2761 Define this in order to add variables describing the
2762 U-Boot build configuration to the default environment.
2763 These will be named arch, cpu, board, vendor, and soc.
2765 Enabling this option will cause the following to be defined:
2773 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2775 Define this in order to add variables describing certain
2776 run-time determined information about the hardware to the
2777 environment. These will be named board_name, board_rev.
2779 CONFIG_DELAY_ENVIRONMENT
2781 Normally the environment is loaded when the board is
2782 intialised so that it is available to U-Boot. This inhibits
2783 that so that the environment is not available until
2784 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2785 this is instead controlled by the value of
2786 /config/load-environment.
2788 - DataFlash Support:
2789 CONFIG_HAS_DATAFLASH
2791 Defining this option enables DataFlash features and
2792 allows to read/write in Dataflash via the standard
2795 - Serial Flash support
2798 Defining this option enables SPI flash commands
2799 'sf probe/read/write/erase/update'.
2801 Usage requires an initial 'probe' to define the serial
2802 flash parameters, followed by read/write/erase/update
2805 The following defaults may be provided by the platform
2806 to handle the common case when only a single serial
2807 flash is present on the system.
2809 CONFIG_SF_DEFAULT_BUS Bus identifier
2810 CONFIG_SF_DEFAULT_CS Chip-select
2811 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2812 CONFIG_SF_DEFAULT_SPEED in Hz
2816 Define this option to include a destructive SPI flash
2819 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2821 Define this option to use the Bank addr/Extended addr
2822 support on SPI flashes which has size > 16Mbytes.
2824 CONFIG_SF_DUAL_FLASH Dual flash memories
2826 Define this option to use dual flash support where two flash
2827 memories can be connected with a given cs line.
2828 currently Xilinx Zynq qspi support these type of connections.
2830 - SystemACE Support:
2833 Adding this option adds support for Xilinx SystemACE
2834 chips attached via some sort of local bus. The address
2835 of the chip must also be defined in the
2836 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2838 #define CONFIG_SYSTEMACE
2839 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2841 When SystemACE support is added, the "ace" device type
2842 becomes available to the fat commands, i.e. fatls.
2844 - TFTP Fixed UDP Port:
2847 If this is defined, the environment variable tftpsrcp
2848 is used to supply the TFTP UDP source port value.
2849 If tftpsrcp isn't defined, the normal pseudo-random port
2850 number generator is used.
2852 Also, the environment variable tftpdstp is used to supply
2853 the TFTP UDP destination port value. If tftpdstp isn't
2854 defined, the normal port 69 is used.
2856 The purpose for tftpsrcp is to allow a TFTP server to
2857 blindly start the TFTP transfer using the pre-configured
2858 target IP address and UDP port. This has the effect of
2859 "punching through" the (Windows XP) firewall, allowing
2860 the remainder of the TFTP transfer to proceed normally.
2861 A better solution is to properly configure the firewall,
2862 but sometimes that is not allowed.
2867 This enables a generic 'hash' command which can produce
2868 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2872 Enable the hash verify command (hash -v). This adds to code
2875 CONFIG_SHA1 - support SHA1 hashing
2876 CONFIG_SHA256 - support SHA256 hashing
2878 Note: There is also a sha1sum command, which should perhaps
2879 be deprecated in favour of 'hash sha1'.
2881 - Freescale i.MX specific commands:
2882 CONFIG_CMD_HDMIDETECT
2883 This enables 'hdmidet' command which returns true if an
2884 HDMI monitor is detected. This command is i.MX 6 specific.
2887 This enables the 'bmode' (bootmode) command for forcing
2888 a boot from specific media.
2890 This is useful for forcing the ROM's usb downloader to
2891 activate upon a watchdog reset which is nice when iterating
2892 on U-Boot. Using the reset button or running bmode normal
2893 will set it back to normal. This command currently
2894 supports i.MX53 and i.MX6.
2899 This enables the RSA algorithm used for FIT image verification
2900 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2902 The signing part is build into mkimage regardless of this
2905 - bootcount support:
2906 CONFIG_BOOTCOUNT_LIMIT
2908 This enables the bootcounter support, see:
2909 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2912 enable special bootcounter support on at91sam9xe based boards.
2914 enable special bootcounter support on blackfin based boards.
2916 enable special bootcounter support on da850 based boards.
2917 CONFIG_BOOTCOUNT_RAM
2918 enable support for the bootcounter in RAM
2919 CONFIG_BOOTCOUNT_I2C
2920 enable support for the bootcounter on an i2c (like RTC) device.
2921 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2922 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2924 CONFIG_BOOTCOUNT_ALEN = address len
2926 - Show boot progress:
2927 CONFIG_SHOW_BOOT_PROGRESS
2929 Defining this option allows to add some board-
2930 specific code (calling a user-provided function
2931 "show_boot_progress(int)") that enables you to show
2932 the system's boot progress on some display (for
2933 example, some LED's) on your board. At the moment,
2934 the following checkpoints are implemented:
2936 - Detailed boot stage timing
2938 Define this option to get detailed timing of each stage
2939 of the boot process.
2941 CONFIG_BOOTSTAGE_USER_COUNT
2942 This is the number of available user bootstage records.
2943 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2944 a new ID will be allocated from this stash. If you exceed
2945 the limit, recording will stop.
2947 CONFIG_BOOTSTAGE_REPORT
2948 Define this to print a report before boot, similar to this:
2950 Timer summary in microseconds:
2953 3,575,678 3,575,678 board_init_f start
2954 3,575,695 17 arch_cpu_init A9
2955 3,575,777 82 arch_cpu_init done
2956 3,659,598 83,821 board_init_r start
2957 3,910,375 250,777 main_loop
2958 29,916,167 26,005,792 bootm_start
2959 30,361,327 445,160 start_kernel
2961 CONFIG_CMD_BOOTSTAGE
2962 Add a 'bootstage' command which supports printing a report
2963 and un/stashing of bootstage data.
2965 CONFIG_BOOTSTAGE_FDT
2966 Stash the bootstage information in the FDT. A root 'bootstage'
2967 node is created with each bootstage id as a child. Each child
2968 has a 'name' property and either 'mark' containing the
2969 mark time in microsecond, or 'accum' containing the
2970 accumulated time for that bootstage id in microseconds.
2975 name = "board_init_f";
2984 Code in the Linux kernel can find this in /proc/devicetree.
2986 Legacy uImage format:
2989 1 common/cmd_bootm.c before attempting to boot an image
2990 -1 common/cmd_bootm.c Image header has bad magic number
2991 2 common/cmd_bootm.c Image header has correct magic number
2992 -2 common/cmd_bootm.c Image header has bad checksum
2993 3 common/cmd_bootm.c Image header has correct checksum
2994 -3 common/cmd_bootm.c Image data has bad checksum
2995 4 common/cmd_bootm.c Image data has correct checksum
2996 -4 common/cmd_bootm.c Image is for unsupported architecture
2997 5 common/cmd_bootm.c Architecture check OK
2998 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2999 6 common/cmd_bootm.c Image Type check OK
3000 -6 common/cmd_bootm.c gunzip uncompression error
3001 -7 common/cmd_bootm.c Unimplemented compression type
3002 7 common/cmd_bootm.c Uncompression OK
3003 8 common/cmd_bootm.c No uncompress/copy overwrite error
3004 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3006 9 common/image.c Start initial ramdisk verification
3007 -10 common/image.c Ramdisk header has bad magic number
3008 -11 common/image.c Ramdisk header has bad checksum
3009 10 common/image.c Ramdisk header is OK
3010 -12 common/image.c Ramdisk data has bad checksum
3011 11 common/image.c Ramdisk data has correct checksum
3012 12 common/image.c Ramdisk verification complete, start loading
3013 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3014 13 common/image.c Start multifile image verification
3015 14 common/image.c No initial ramdisk, no multifile, continue.
3017 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3019 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3020 -31 post/post.c POST test failed, detected by post_output_backlog()
3021 -32 post/post.c POST test failed, detected by post_run_single()
3023 34 common/cmd_doc.c before loading a Image from a DOC device
3024 -35 common/cmd_doc.c Bad usage of "doc" command
3025 35 common/cmd_doc.c correct usage of "doc" command
3026 -36 common/cmd_doc.c No boot device
3027 36 common/cmd_doc.c correct boot device
3028 -37 common/cmd_doc.c Unknown Chip ID on boot device
3029 37 common/cmd_doc.c correct chip ID found, device available
3030 -38 common/cmd_doc.c Read Error on boot device
3031 38 common/cmd_doc.c reading Image header from DOC device OK
3032 -39 common/cmd_doc.c Image header has bad magic number
3033 39 common/cmd_doc.c Image header has correct magic number
3034 -40 common/cmd_doc.c Error reading Image from DOC device
3035 40 common/cmd_doc.c Image header has correct magic number
3036 41 common/cmd_ide.c before loading a Image from a IDE device
3037 -42 common/cmd_ide.c Bad usage of "ide" command
3038 42 common/cmd_ide.c correct usage of "ide" command
3039 -43 common/cmd_ide.c No boot device
3040 43 common/cmd_ide.c boot device found
3041 -44 common/cmd_ide.c Device not available
3042 44 common/cmd_ide.c Device available
3043 -45 common/cmd_ide.c wrong partition selected
3044 45 common/cmd_ide.c partition selected
3045 -46 common/cmd_ide.c Unknown partition table
3046 46 common/cmd_ide.c valid partition table found
3047 -47 common/cmd_ide.c Invalid partition type
3048 47 common/cmd_ide.c correct partition type
3049 -48 common/cmd_ide.c Error reading Image Header on boot device
3050 48 common/cmd_ide.c reading Image Header from IDE device OK
3051 -49 common/cmd_ide.c Image header has bad magic number
3052 49 common/cmd_ide.c Image header has correct magic number
3053 -50 common/cmd_ide.c Image header has bad checksum
3054 50 common/cmd_ide.c Image header has correct checksum
3055 -51 common/cmd_ide.c Error reading Image from IDE device
3056 51 common/cmd_ide.c reading Image from IDE device OK
3057 52 common/cmd_nand.c before loading a Image from a NAND device
3058 -53 common/cmd_nand.c Bad usage of "nand" command
3059 53 common/cmd_nand.c correct usage of "nand" command
3060 -54 common/cmd_nand.c No boot device
3061 54 common/cmd_nand.c boot device found
3062 -55 common/cmd_nand.c Unknown Chip ID on boot device
3063 55 common/cmd_nand.c correct chip ID found, device available
3064 -56 common/cmd_nand.c Error reading Image Header on boot device
3065 56 common/cmd_nand.c reading Image Header from NAND device OK
3066 -57 common/cmd_nand.c Image header has bad magic number
3067 57 common/cmd_nand.c Image header has correct magic number
3068 -58 common/cmd_nand.c Error reading Image from NAND device
3069 58 common/cmd_nand.c reading Image from NAND device OK
3071 -60 common/env_common.c Environment has a bad CRC, using default
3073 64 net/eth.c starting with Ethernet configuration.
3074 -64 net/eth.c no Ethernet found.
3075 65 net/eth.c Ethernet found.
3077 -80 common/cmd_net.c usage wrong
3078 80 common/cmd_net.c before calling NetLoop()
3079 -81 common/cmd_net.c some error in NetLoop() occurred
3080 81 common/cmd_net.c NetLoop() back without error
3081 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3082 82 common/cmd_net.c trying automatic boot
3083 83 common/cmd_net.c running "source" command
3084 -83 common/cmd_net.c some error in automatic boot or "source" command
3085 84 common/cmd_net.c end without errors
3090 100 common/cmd_bootm.c Kernel FIT Image has correct format
3091 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3092 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3093 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3094 102 common/cmd_bootm.c Kernel unit name specified
3095 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3096 103 common/cmd_bootm.c Found configuration node
3097 104 common/cmd_bootm.c Got kernel subimage node offset
3098 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3099 105 common/cmd_bootm.c Kernel subimage hash verification OK
3100 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3101 106 common/cmd_bootm.c Architecture check OK
3102 -106 common/cmd_bootm.c Kernel subimage has wrong type
3103 107 common/cmd_bootm.c Kernel subimage type OK
3104 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3105 108 common/cmd_bootm.c Got kernel subimage data/size
3106 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3107 -109 common/cmd_bootm.c Can't get kernel subimage type
3108 -110 common/cmd_bootm.c Can't get kernel subimage comp
3109 -111 common/cmd_bootm.c Can't get kernel subimage os
3110 -112 common/cmd_bootm.c Can't get kernel subimage load address
3111 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3113 120 common/image.c Start initial ramdisk verification
3114 -120 common/image.c Ramdisk FIT image has incorrect format
3115 121 common/image.c Ramdisk FIT image has correct format
3116 122 common/image.c No ramdisk subimage unit name, using configuration
3117 -122 common/image.c Can't get configuration for ramdisk subimage
3118 123 common/image.c Ramdisk unit name specified
3119 -124 common/image.c Can't get ramdisk subimage node offset
3120 125 common/image.c Got ramdisk subimage node offset
3121 -125 common/image.c Ramdisk subimage hash verification failed
3122 126 common/image.c Ramdisk subimage hash verification OK
3123 -126 common/image.c Ramdisk subimage for unsupported architecture
3124 127 common/image.c Architecture check OK
3125 -127 common/image.c Can't get ramdisk subimage data/size
3126 128 common/image.c Got ramdisk subimage data/size
3127 129 common/image.c Can't get ramdisk load address
3128 -129 common/image.c Got ramdisk load address
3130 -130 common/cmd_doc.c Incorrect FIT image format
3131 131 common/cmd_doc.c FIT image format OK
3133 -140 common/cmd_ide.c Incorrect FIT image format
3134 141 common/cmd_ide.c FIT image format OK
3136 -150 common/cmd_nand.c Incorrect FIT image format
3137 151 common/cmd_nand.c FIT image format OK
3139 - FIT image support:
3141 Enable support for the FIT uImage format.
3143 CONFIG_FIT_BEST_MATCH
3144 When no configuration is explicitly selected, default to the
3145 one whose fdt's compatibility field best matches that of
3146 U-Boot itself. A match is considered "best" if it matches the
3147 most specific compatibility entry of U-Boot's fdt's root node.
3148 The order of entries in the configuration's fdt is ignored.
3150 CONFIG_FIT_SIGNATURE
3151 This option enables signature verification of FIT uImages,
3152 using a hash signed and verified using RSA. See
3153 doc/uImage.FIT/signature.txt for more details.
3155 - Standalone program support:
3156 CONFIG_STANDALONE_LOAD_ADDR
3158 This option defines a board specific value for the
3159 address where standalone program gets loaded, thus
3160 overwriting the architecture dependent default
3163 - Frame Buffer Address:
3166 Define CONFIG_FB_ADDR if you want to use specific
3167 address for frame buffer. This is typically the case
3168 when using a graphics controller has separate video
3169 memory. U-Boot will then place the frame buffer at
3170 the given address instead of dynamically reserving it
3171 in system RAM by calling lcd_setmem(), which grabs
3172 the memory for the frame buffer depending on the
3173 configured panel size.
3175 Please see board_init_f function.
3177 - Automatic software updates via TFTP server
3179 CONFIG_UPDATE_TFTP_CNT_MAX
3180 CONFIG_UPDATE_TFTP_MSEC_MAX
3182 These options enable and control the auto-update feature;
3183 for a more detailed description refer to doc/README.update.
3185 - MTD Support (mtdparts command, UBI support)
3188 Adds the MTD device infrastructure from the Linux kernel.
3189 Needed for mtdparts command support.
3191 CONFIG_MTD_PARTITIONS
3193 Adds the MTD partitioning infrastructure from the Linux
3194 kernel. Needed for UBI support.
3199 Adds commands for interacting with MTD partitions formatted
3200 with the UBI flash translation layer
3202 Requires also defining CONFIG_RBTREE
3204 CONFIG_UBI_SILENCE_MSG
3206 Make the verbose messages from UBI stop printing. This leaves
3207 warnings and errors enabled.
3212 Adds commands for interacting with UBI volumes formatted as
3213 UBIFS. UBIFS is read-only in u-boot.
3215 Requires UBI support as well as CONFIG_LZO
3217 CONFIG_UBIFS_SILENCE_MSG
3219 Make the verbose messages from UBIFS stop printing. This leaves
3220 warnings and errors enabled.
3224 Enable building of SPL globally.
3227 LDSCRIPT for linking the SPL binary.
3229 CONFIG_SPL_MAX_FOOTPRINT
3230 Maximum size in memory allocated to the SPL, BSS included.
3231 When defined, the linker checks that the actual memory
3232 used by SPL from _start to __bss_end does not exceed it.
3233 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3234 must not be both defined at the same time.
3237 Maximum size of the SPL image (text, data, rodata, and
3238 linker lists sections), BSS excluded.
3239 When defined, the linker checks that the actual size does
3242 CONFIG_SPL_TEXT_BASE
3243 TEXT_BASE for linking the SPL binary.
3245 CONFIG_SPL_RELOC_TEXT_BASE
3246 Address to relocate to. If unspecified, this is equal to
3247 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3249 CONFIG_SPL_BSS_START_ADDR
3250 Link address for the BSS within the SPL binary.
3252 CONFIG_SPL_BSS_MAX_SIZE
3253 Maximum size in memory allocated to the SPL BSS.
3254 When defined, the linker checks that the actual memory used
3255 by SPL from __bss_start to __bss_end does not exceed it.
3256 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3257 must not be both defined at the same time.
3260 Adress of the start of the stack SPL will use
3262 CONFIG_SPL_RELOC_STACK
3263 Adress of the start of the stack SPL will use after
3264 relocation. If unspecified, this is equal to
3267 CONFIG_SYS_SPL_MALLOC_START
3268 Starting address of the malloc pool used in SPL.
3270 CONFIG_SYS_SPL_MALLOC_SIZE
3271 The size of the malloc pool used in SPL.
3273 CONFIG_SPL_FRAMEWORK
3274 Enable the SPL framework under common/. This framework
3275 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3276 NAND loading of the Linux Kernel.
3279 Enable booting directly to an OS from SPL.
3280 See also: doc/README.falcon
3282 CONFIG_SPL_DISPLAY_PRINT
3283 For ARM, enable an optional function to print more information
3284 about the running system.
3286 CONFIG_SPL_INIT_MINIMAL
3287 Arch init code should be built for a very small image
3289 CONFIG_SPL_LIBCOMMON_SUPPORT
3290 Support for common/libcommon.o in SPL binary
3292 CONFIG_SPL_LIBDISK_SUPPORT
3293 Support for disk/libdisk.o in SPL binary
3295 CONFIG_SPL_I2C_SUPPORT
3296 Support for drivers/i2c/libi2c.o in SPL binary
3298 CONFIG_SPL_GPIO_SUPPORT
3299 Support for drivers/gpio/libgpio.o in SPL binary
3301 CONFIG_SPL_MMC_SUPPORT
3302 Support for drivers/mmc/libmmc.o in SPL binary
3304 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3305 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3306 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3307 Address, size and partition on the MMC to load U-Boot from
3308 when the MMC is being used in raw mode.
3310 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3311 Sector to load kernel uImage from when MMC is being
3312 used in raw mode (for Falcon mode)
3314 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3315 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3316 Sector and number of sectors to load kernel argument
3317 parameters from when MMC is being used in raw mode
3320 CONFIG_SPL_FAT_SUPPORT
3321 Support for fs/fat/libfat.o in SPL binary
3323 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3324 Filename to read to load U-Boot when reading from FAT
3326 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3327 Filename to read to load kernel uImage when reading
3328 from FAT (for Falcon mode)
3330 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3331 Filename to read to load kernel argument parameters
3332 when reading from FAT (for Falcon mode)
3334 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3335 Set this for NAND SPL on PPC mpc83xx targets, so that
3336 start.S waits for the rest of the SPL to load before
3337 continuing (the hardware starts execution after just
3338 loading the first page rather than the full 4K).
3340 CONFIG_SPL_SKIP_RELOCATE
3341 Avoid SPL relocation
3343 CONFIG_SPL_NAND_BASE
3344 Include nand_base.c in the SPL. Requires
3345 CONFIG_SPL_NAND_DRIVERS.
3347 CONFIG_SPL_NAND_DRIVERS
3348 SPL uses normal NAND drivers, not minimal drivers.
3351 Include standard software ECC in the SPL
3353 CONFIG_SPL_NAND_SIMPLE
3354 Support for NAND boot using simple NAND drivers that
3355 expose the cmd_ctrl() interface.
3357 CONFIG_SPL_MTD_SUPPORT
3358 Support for the MTD subsystem within SPL. Useful for
3359 environment on NAND support within SPL.
3361 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3362 Set for the SPL on PPC mpc8xxx targets, support for
3363 drivers/ddr/fsl/libddr.o in SPL binary.
3365 CONFIG_SPL_COMMON_INIT_DDR
3366 Set for common ddr init with serial presence detect in
3369 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3370 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3371 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3372 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3373 CONFIG_SYS_NAND_ECCBYTES
3374 Defines the size and behavior of the NAND that SPL uses
3377 CONFIG_SPL_NAND_BOOT
3378 Add support NAND boot
3380 CONFIG_SYS_NAND_U_BOOT_OFFS
3381 Location in NAND to read U-Boot from
3383 CONFIG_SYS_NAND_U_BOOT_DST
3384 Location in memory to load U-Boot to
3386 CONFIG_SYS_NAND_U_BOOT_SIZE
3387 Size of image to load
3389 CONFIG_SYS_NAND_U_BOOT_START
3390 Entry point in loaded image to jump to
3392 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3393 Define this if you need to first read the OOB and then the
3394 data. This is used for example on davinci plattforms.
3396 CONFIG_SPL_OMAP3_ID_NAND
3397 Support for an OMAP3-specific set of functions to return the
3398 ID and MFR of the first attached NAND chip, if present.
3400 CONFIG_SPL_SERIAL_SUPPORT
3401 Support for drivers/serial/libserial.o in SPL binary
3403 CONFIG_SPL_SPI_FLASH_SUPPORT
3404 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3406 CONFIG_SPL_SPI_SUPPORT
3407 Support for drivers/spi/libspi.o in SPL binary
3409 CONFIG_SPL_RAM_DEVICE
3410 Support for running image already present in ram, in SPL binary
3412 CONFIG_SPL_LIBGENERIC_SUPPORT
3413 Support for lib/libgeneric.o in SPL binary
3415 CONFIG_SPL_ENV_SUPPORT
3416 Support for the environment operating in SPL binary
3418 CONFIG_SPL_NET_SUPPORT
3419 Support for the net/libnet.o in SPL binary.
3420 It conflicts with SPL env from storage medium specified by
3421 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3424 Image offset to which the SPL should be padded before appending
3425 the SPL payload. By default, this is defined as
3426 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3427 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3428 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3431 Final target image containing SPL and payload. Some SPLs
3432 use an arch-specific makefile fragment instead, for
3433 example if more than one image needs to be produced.
3435 CONFIG_FIT_SPL_PRINT
3436 Printing information about a FIT image adds quite a bit of
3437 code to SPL. So this is normally disabled in SPL. Use this
3438 option to re-enable it. This will affect the output of the
3439 bootm command when booting a FIT image.
3443 Enable building of TPL globally.
3446 Image offset to which the TPL should be padded before appending
3447 the TPL payload. By default, this is defined as
3448 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3449 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3450 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3455 [so far only for SMDK2400 boards]
3457 - Modem support enable:
3458 CONFIG_MODEM_SUPPORT
3460 - RTS/CTS Flow control enable:
3463 - Modem debug support:
3464 CONFIG_MODEM_SUPPORT_DEBUG
3466 Enables debugging stuff (char screen[1024], dbg())
3467 for modem support. Useful only with BDI2000.
3469 - Interrupt support (PPC):
3471 There are common interrupt_init() and timer_interrupt()
3472 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3473 for CPU specific initialization. interrupt_init_cpu()
3474 should set decrementer_count to appropriate value. If
3475 CPU resets decrementer automatically after interrupt
3476 (ppc4xx) it should set decrementer_count to zero.
3477 timer_interrupt() calls timer_interrupt_cpu() for CPU
3478 specific handling. If board has watchdog / status_led
3479 / other_activity_monitor it works automatically from
3480 general timer_interrupt().
3484 In the target system modem support is enabled when a
3485 specific key (key combination) is pressed during
3486 power-on. Otherwise U-Boot will boot normally
3487 (autoboot). The key_pressed() function is called from
3488 board_init(). Currently key_pressed() is a dummy
3489 function, returning 1 and thus enabling modem
3492 If there are no modem init strings in the
3493 environment, U-Boot proceed to autoboot; the
3494 previous output (banner, info printfs) will be
3497 See also: doc/README.Modem
3499 Board initialization settings:
3500 ------------------------------
3502 During Initialization u-boot calls a number of board specific functions
3503 to allow the preparation of board specific prerequisites, e.g. pin setup
3504 before drivers are initialized. To enable these callbacks the
3505 following configuration macros have to be defined. Currently this is
3506 architecture specific, so please check arch/your_architecture/lib/board.c
3507 typically in board_init_f() and board_init_r().
3509 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3510 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3511 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3512 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3514 Configuration Settings:
3515 -----------------------
3517 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3518 Optionally it can be defined to support 64-bit memory commands.
3520 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3521 undefine this when you're short of memory.
3523 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3524 width of the commands listed in the 'help' command output.
3526 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3527 prompt for user input.
3529 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3531 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3533 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3535 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3536 the application (usually a Linux kernel) when it is
3539 - CONFIG_SYS_BAUDRATE_TABLE:
3540 List of legal baudrate settings for this board.
3542 - CONFIG_SYS_CONSOLE_INFO_QUIET
3543 Suppress display of console information at boot.
3545 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3546 If the board specific function
3547 extern int overwrite_console (void);
3548 returns 1, the stdin, stderr and stdout are switched to the
3549 serial port, else the settings in the environment are used.
3551 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3552 Enable the call to overwrite_console().
3554 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3555 Enable overwrite of previous console environment settings.
3557 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3558 Begin and End addresses of the area used by the
3561 - CONFIG_SYS_ALT_MEMTEST:
3562 Enable an alternate, more extensive memory test.
3564 - CONFIG_SYS_MEMTEST_SCRATCH:
3565 Scratch address used by the alternate memory test
3566 You only need to set this if address zero isn't writeable
3568 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3569 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3570 this specified memory area will get subtracted from the top
3571 (end) of RAM and won't get "touched" at all by U-Boot. By
3572 fixing up gd->ram_size the Linux kernel should gets passed
3573 the now "corrected" memory size and won't touch it either.
3574 This should work for arch/ppc and arch/powerpc. Only Linux
3575 board ports in arch/powerpc with bootwrapper support that
3576 recalculate the memory size from the SDRAM controller setup
3577 will have to get fixed in Linux additionally.
3579 This option can be used as a workaround for the 440EPx/GRx
3580 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3583 WARNING: Please make sure that this value is a multiple of
3584 the Linux page size (normally 4k). If this is not the case,
3585 then the end address of the Linux memory will be located at a
3586 non page size aligned address and this could cause major
3589 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3590 Enable temporary baudrate change while serial download
3592 - CONFIG_SYS_SDRAM_BASE:
3593 Physical start address of SDRAM. _Must_ be 0 here.
3595 - CONFIG_SYS_MBIO_BASE:
3596 Physical start address of Motherboard I/O (if using a
3599 - CONFIG_SYS_FLASH_BASE:
3600 Physical start address of Flash memory.
3602 - CONFIG_SYS_MONITOR_BASE:
3603 Physical start address of boot monitor code (set by
3604 make config files to be same as the text base address
3605 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3606 CONFIG_SYS_FLASH_BASE when booting from flash.
3608 - CONFIG_SYS_MONITOR_LEN:
3609 Size of memory reserved for monitor code, used to
3610 determine _at_compile_time_ (!) if the environment is
3611 embedded within the U-Boot image, or in a separate
3614 - CONFIG_SYS_MALLOC_LEN:
3615 Size of DRAM reserved for malloc() use.
3617 - CONFIG_SYS_BOOTM_LEN:
3618 Normally compressed uImages are limited to an
3619 uncompressed size of 8 MBytes. If this is not enough,
3620 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3621 to adjust this setting to your needs.
3623 - CONFIG_SYS_BOOTMAPSZ:
3624 Maximum size of memory mapped by the startup code of
3625 the Linux kernel; all data that must be processed by
3626 the Linux kernel (bd_info, boot arguments, FDT blob if
3627 used) must be put below this limit, unless "bootm_low"
3628 environment variable is defined and non-zero. In such case
3629 all data for the Linux kernel must be between "bootm_low"
3630 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3631 variable "bootm_mapsize" will override the value of
3632 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3633 then the value in "bootm_size" will be used instead.
3635 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3636 Enable initrd_high functionality. If defined then the
3637 initrd_high feature is enabled and the bootm ramdisk subcommand
3640 - CONFIG_SYS_BOOT_GET_CMDLINE:
3641 Enables allocating and saving kernel cmdline in space between
3642 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3644 - CONFIG_SYS_BOOT_GET_KBD:
3645 Enables allocating and saving a kernel copy of the bd_info in
3646 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3648 - CONFIG_SYS_MAX_FLASH_BANKS:
3649 Max number of Flash memory banks
3651 - CONFIG_SYS_MAX_FLASH_SECT:
3652 Max number of sectors on a Flash chip
3654 - CONFIG_SYS_FLASH_ERASE_TOUT:
3655 Timeout for Flash erase operations (in ms)
3657 - CONFIG_SYS_FLASH_WRITE_TOUT:
3658 Timeout for Flash write operations (in ms)
3660 - CONFIG_SYS_FLASH_LOCK_TOUT
3661 Timeout for Flash set sector lock bit operation (in ms)
3663 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3664 Timeout for Flash clear lock bits operation (in ms)
3666 - CONFIG_SYS_FLASH_PROTECTION
3667 If defined, hardware flash sectors protection is used
3668 instead of U-Boot software protection.
3670 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3672 Enable TFTP transfers directly to flash memory;
3673 without this option such a download has to be
3674 performed in two steps: (1) download to RAM, and (2)
3675 copy from RAM to flash.
3677 The two-step approach is usually more reliable, since
3678 you can check if the download worked before you erase
3679 the flash, but in some situations (when system RAM is
3680 too limited to allow for a temporary copy of the
3681 downloaded image) this option may be very useful.
3683 - CONFIG_SYS_FLASH_CFI:
3684 Define if the flash driver uses extra elements in the
3685 common flash structure for storing flash geometry.
3687 - CONFIG_FLASH_CFI_DRIVER
3688 This option also enables the building of the cfi_flash driver
3689 in the drivers directory
3691 - CONFIG_FLASH_CFI_MTD
3692 This option enables the building of the cfi_mtd driver
3693 in the drivers directory. The driver exports CFI flash
3696 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3697 Use buffered writes to flash.
3699 - CONFIG_FLASH_SPANSION_S29WS_N
3700 s29ws-n MirrorBit flash has non-standard addresses for buffered
3703 - CONFIG_SYS_FLASH_QUIET_TEST
3704 If this option is defined, the common CFI flash doesn't
3705 print it's warning upon not recognized FLASH banks. This
3706 is useful, if some of the configured banks are only
3707 optionally available.
3709 - CONFIG_FLASH_SHOW_PROGRESS
3710 If defined (must be an integer), print out countdown
3711 digits and dots. Recommended value: 45 (9..1) for 80
3712 column displays, 15 (3..1) for 40 column displays.
3714 - CONFIG_FLASH_VERIFY
3715 If defined, the content of the flash (destination) is compared
3716 against the source after the write operation. An error message
3717 will be printed when the contents are not identical.
3718 Please note that this option is useless in nearly all cases,
3719 since such flash programming errors usually are detected earlier
3720 while unprotecting/erasing/programming. Please only enable
3721 this option if you really know what you are doing.
3723 - CONFIG_SYS_RX_ETH_BUFFER:
3724 Defines the number of Ethernet receive buffers. On some
3725 Ethernet controllers it is recommended to set this value
3726 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3727 buffers can be full shortly after enabling the interface
3728 on high Ethernet traffic.
3729 Defaults to 4 if not defined.
3731 - CONFIG_ENV_MAX_ENTRIES
3733 Maximum number of entries in the hash table that is used
3734 internally to store the environment settings. The default
3735 setting is supposed to be generous and should work in most
3736 cases. This setting can be used to tune behaviour; see
3737 lib/hashtable.c for details.
3739 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3740 - CONFIG_ENV_FLAGS_LIST_STATIC
3741 Enable validation of the values given to environment variables when
3742 calling env set. Variables can be restricted to only decimal,
3743 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3744 the variables can also be restricted to IP address or MAC address.
3746 The format of the list is:
3747 type_attribute = [s|d|x|b|i|m]
3748 access_atribute = [a|r|o|c]
3749 attributes = type_attribute[access_atribute]
3750 entry = variable_name[:attributes]
3753 The type attributes are:
3754 s - String (default)
3757 b - Boolean ([1yYtT|0nNfF])
3761 The access attributes are:
3767 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3768 Define this to a list (string) to define the ".flags"
3769 envirnoment variable in the default or embedded environment.
3771 - CONFIG_ENV_FLAGS_LIST_STATIC
3772 Define this to a list (string) to define validation that
3773 should be done if an entry is not found in the ".flags"
3774 environment variable. To override a setting in the static
3775 list, simply add an entry for the same variable name to the
3778 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3779 If defined, don't allow the -f switch to env set override variable
3782 - CONFIG_SYS_GENERIC_BOARD
3783 This selects the architecture-generic board system instead of the
3784 architecture-specific board files. It is intended to move boards
3785 to this new framework over time. Defining this will disable the
3786 arch/foo/lib/board.c file and use common/board_f.c and
3787 common/board_r.c instead. To use this option your architecture
3788 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3789 its config.mk file). If you find problems enabling this option on
3790 your board please report the problem and send patches!
3792 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3793 This is set by OMAP boards for the max time that reset should
3794 be asserted. See doc/README.omap-reset-time for details on how
3795 the value can be calulated on a given board.
3797 The following definitions that deal with the placement and management
3798 of environment data (variable area); in general, we support the
3799 following configurations:
3801 - CONFIG_BUILD_ENVCRC:
3803 Builds up envcrc with the target environment so that external utils
3804 may easily extract it and embed it in final U-Boot images.
3806 - CONFIG_ENV_IS_IN_FLASH:
3808 Define this if the environment is in flash memory.
3810 a) The environment occupies one whole flash sector, which is
3811 "embedded" in the text segment with the U-Boot code. This
3812 happens usually with "bottom boot sector" or "top boot
3813 sector" type flash chips, which have several smaller
3814 sectors at the start or the end. For instance, such a
3815 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3816 such a case you would place the environment in one of the
3817 4 kB sectors - with U-Boot code before and after it. With
3818 "top boot sector" type flash chips, you would put the
3819 environment in one of the last sectors, leaving a gap
3820 between U-Boot and the environment.
3822 - CONFIG_ENV_OFFSET:
3824 Offset of environment data (variable area) to the
3825 beginning of flash memory; for instance, with bottom boot
3826 type flash chips the second sector can be used: the offset
3827 for this sector is given here.
3829 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3833 This is just another way to specify the start address of
3834 the flash sector containing the environment (instead of
3837 - CONFIG_ENV_SECT_SIZE:
3839 Size of the sector containing the environment.
3842 b) Sometimes flash chips have few, equal sized, BIG sectors.
3843 In such a case you don't want to spend a whole sector for
3848 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3849 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3850 of this flash sector for the environment. This saves
3851 memory for the RAM copy of the environment.
3853 It may also save flash memory if you decide to use this
3854 when your environment is "embedded" within U-Boot code,
3855 since then the remainder of the flash sector could be used
3856 for U-Boot code. It should be pointed out that this is
3857 STRONGLY DISCOURAGED from a robustness point of view:
3858 updating the environment in flash makes it always
3859 necessary to erase the WHOLE sector. If something goes
3860 wrong before the contents has been restored from a copy in
3861 RAM, your target system will be dead.
3863 - CONFIG_ENV_ADDR_REDUND
3864 CONFIG_ENV_SIZE_REDUND
3866 These settings describe a second storage area used to hold
3867 a redundant copy of the environment data, so that there is
3868 a valid backup copy in case there is a power failure during
3869 a "saveenv" operation.
3871 BE CAREFUL! Any changes to the flash layout, and some changes to the
3872 source code will make it necessary to adapt <board>/u-boot.lds*
3876 - CONFIG_ENV_IS_IN_NVRAM:
3878 Define this if you have some non-volatile memory device
3879 (NVRAM, battery buffered SRAM) which you want to use for the
3885 These two #defines are used to determine the memory area you
3886 want to use for environment. It is assumed that this memory
3887 can just be read and written to, without any special
3890 BE CAREFUL! The first access to the environment happens quite early
3891 in U-Boot initalization (when we try to get the setting of for the
3892 console baudrate). You *MUST* have mapped your NVRAM area then, or
3895 Please note that even with NVRAM we still use a copy of the
3896 environment in RAM: we could work on NVRAM directly, but we want to
3897 keep settings there always unmodified except somebody uses "saveenv"
3898 to save the current settings.
3901 - CONFIG_ENV_IS_IN_EEPROM:
3903 Use this if you have an EEPROM or similar serial access
3904 device and a driver for it.
3906 - CONFIG_ENV_OFFSET:
3909 These two #defines specify the offset and size of the
3910 environment area within the total memory of your EEPROM.
3912 - CONFIG_SYS_I2C_EEPROM_ADDR:
3913 If defined, specified the chip address of the EEPROM device.
3914 The default address is zero.
3916 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3917 If defined, the number of bits used to address bytes in a
3918 single page in the EEPROM device. A 64 byte page, for example
3919 would require six bits.
3921 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3922 If defined, the number of milliseconds to delay between
3923 page writes. The default is zero milliseconds.
3925 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3926 The length in bytes of the EEPROM memory array address. Note
3927 that this is NOT the chip address length!
3929 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3930 EEPROM chips that implement "address overflow" are ones
3931 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3932 address and the extra bits end up in the "chip address" bit
3933 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3936 Note that we consider the length of the address field to
3937 still be one byte because the extra address bits are hidden
3938 in the chip address.
3940 - CONFIG_SYS_EEPROM_SIZE:
3941 The size in bytes of the EEPROM device.
3943 - CONFIG_ENV_EEPROM_IS_ON_I2C
3944 define this, if you have I2C and SPI activated, and your
3945 EEPROM, which holds the environment, is on the I2C bus.
3947 - CONFIG_I2C_ENV_EEPROM_BUS
3948 if you have an Environment on an EEPROM reached over
3949 I2C muxes, you can define here, how to reach this
3950 EEPROM. For example:
3952 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3954 EEPROM which holds the environment, is reached over
3955 a pca9547 i2c mux with address 0x70, channel 3.
3957 - CONFIG_ENV_IS_IN_DATAFLASH:
3959 Define this if you have a DataFlash memory device which you
3960 want to use for the environment.
3962 - CONFIG_ENV_OFFSET:
3966 These three #defines specify the offset and size of the
3967 environment area within the total memory of your DataFlash placed
3968 at the specified address.
3970 - CONFIG_ENV_IS_IN_REMOTE:
3972 Define this if you have a remote memory space which you
3973 want to use for the local device's environment.
3978 These two #defines specify the address and size of the
3979 environment area within the remote memory space. The
3980 local device can get the environment from remote memory
3981 space by SRIO or PCIE links.
3983 BE CAREFUL! For some special cases, the local device can not use
3984 "saveenv" command. For example, the local device will get the
3985 environment stored in a remote NOR flash by SRIO or PCIE link,
3986 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3988 - CONFIG_ENV_IS_IN_NAND:
3990 Define this if you have a NAND device which you want to use
3991 for the environment.
3993 - CONFIG_ENV_OFFSET:
3996 These two #defines specify the offset and size of the environment
3997 area within the first NAND device. CONFIG_ENV_OFFSET must be
3998 aligned to an erase block boundary.
4000 - CONFIG_ENV_OFFSET_REDUND (optional):
4002 This setting describes a second storage area of CONFIG_ENV_SIZE
4003 size used to hold a redundant copy of the environment data, so
4004 that there is a valid backup copy in case there is a power failure
4005 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4006 aligned to an erase block boundary.
4008 - CONFIG_ENV_RANGE (optional):
4010 Specifies the length of the region in which the environment
4011 can be written. This should be a multiple of the NAND device's
4012 block size. Specifying a range with more erase blocks than
4013 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4014 the range to be avoided.
4016 - CONFIG_ENV_OFFSET_OOB (optional):
4018 Enables support for dynamically retrieving the offset of the
4019 environment from block zero's out-of-band data. The
4020 "nand env.oob" command can be used to record this offset.
4021 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4022 using CONFIG_ENV_OFFSET_OOB.
4024 - CONFIG_NAND_ENV_DST
4026 Defines address in RAM to which the nand_spl code should copy the
4027 environment. If redundant environment is used, it will be copied to
4028 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4030 - CONFIG_ENV_IS_IN_UBI:
4032 Define this if you have an UBI volume that you want to use for the
4033 environment. This has the benefit of wear-leveling the environment
4034 accesses, which is important on NAND.
4036 - CONFIG_ENV_UBI_PART:
4038 Define this to a string that is the mtd partition containing the UBI.
4040 - CONFIG_ENV_UBI_VOLUME:
4042 Define this to the name of the volume that you want to store the
4045 - CONFIG_ENV_UBI_VOLUME_REDUND:
4047 Define this to the name of another volume to store a second copy of
4048 the environment in. This will enable redundant environments in UBI.
4049 It is assumed that both volumes are in the same MTD partition.
4051 - CONFIG_UBI_SILENCE_MSG
4052 - CONFIG_UBIFS_SILENCE_MSG
4054 You will probably want to define these to avoid a really noisy system
4055 when storing the env in UBI.
4057 - CONFIG_ENV_IS_IN_MMC:
4059 Define this if you have an MMC device which you want to use for the
4062 - CONFIG_SYS_MMC_ENV_DEV:
4064 Specifies which MMC device the environment is stored in.
4066 - CONFIG_SYS_MMC_ENV_PART (optional):
4068 Specifies which MMC partition the environment is stored in. If not
4069 set, defaults to partition 0, the user area. Common values might be
4070 1 (first MMC boot partition), 2 (second MMC boot partition).
4072 - CONFIG_ENV_OFFSET:
4075 These two #defines specify the offset and size of the environment
4076 area within the specified MMC device.
4078 If offset is positive (the usual case), it is treated as relative to
4079 the start of the MMC partition. If offset is negative, it is treated
4080 as relative to the end of the MMC partition. This can be useful if
4081 your board may be fitted with different MMC devices, which have
4082 different sizes for the MMC partitions, and you always want the
4083 environment placed at the very end of the partition, to leave the
4084 maximum possible space before it, to store other data.
4086 These two values are in units of bytes, but must be aligned to an
4087 MMC sector boundary.
4089 - CONFIG_ENV_OFFSET_REDUND (optional):
4091 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4092 hold a redundant copy of the environment data. This provides a
4093 valid backup copy in case the other copy is corrupted, e.g. due
4094 to a power failure during a "saveenv" operation.
4096 This value may also be positive or negative; this is handled in the
4097 same way as CONFIG_ENV_OFFSET.
4099 This value is also in units of bytes, but must also be aligned to
4100 an MMC sector boundary.
4102 - CONFIG_ENV_SIZE_REDUND (optional):
4104 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4105 set. If this value is set, it must be set to the same value as
4108 - CONFIG_SYS_SPI_INIT_OFFSET
4110 Defines offset to the initial SPI buffer area in DPRAM. The
4111 area is used at an early stage (ROM part) if the environment
4112 is configured to reside in the SPI EEPROM: We need a 520 byte
4113 scratch DPRAM area. It is used between the two initialization
4114 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4115 to be a good choice since it makes it far enough from the
4116 start of the data area as well as from the stack pointer.
4118 Please note that the environment is read-only until the monitor
4119 has been relocated to RAM and a RAM copy of the environment has been
4120 created; also, when using EEPROM you will have to use getenv_f()
4121 until then to read environment variables.
4123 The environment is protected by a CRC32 checksum. Before the monitor
4124 is relocated into RAM, as a result of a bad CRC you will be working
4125 with the compiled-in default environment - *silently*!!! [This is
4126 necessary, because the first environment variable we need is the
4127 "baudrate" setting for the console - if we have a bad CRC, we don't
4128 have any device yet where we could complain.]
4130 Note: once the monitor has been relocated, then it will complain if
4131 the default environment is used; a new CRC is computed as soon as you
4132 use the "saveenv" command to store a valid environment.
4134 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4135 Echo the inverted Ethernet link state to the fault LED.
4137 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4138 also needs to be defined.
4140 - CONFIG_SYS_FAULT_MII_ADDR:
4141 MII address of the PHY to check for the Ethernet link state.
4143 - CONFIG_NS16550_MIN_FUNCTIONS:
4144 Define this if you desire to only have use of the NS16550_init
4145 and NS16550_putc functions for the serial driver located at
4146 drivers/serial/ns16550.c. This option is useful for saving
4147 space for already greatly restricted images, including but not
4148 limited to NAND_SPL configurations.
4150 - CONFIG_DISPLAY_BOARDINFO
4151 Display information about the board that U-Boot is running on
4152 when U-Boot starts up. The board function checkboard() is called
4155 - CONFIG_DISPLAY_BOARDINFO_LATE
4156 Similar to the previous option, but display this information
4157 later, once stdio is running and output goes to the LCD, if
4160 Low Level (hardware related) configuration options:
4161 ---------------------------------------------------
4163 - CONFIG_SYS_CACHELINE_SIZE:
4164 Cache Line Size of the CPU.
4166 - CONFIG_SYS_DEFAULT_IMMR:
4167 Default address of the IMMR after system reset.
4169 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4170 and RPXsuper) to be able to adjust the position of
4171 the IMMR register after a reset.
4173 - CONFIG_SYS_CCSRBAR_DEFAULT:
4174 Default (power-on reset) physical address of CCSR on Freescale
4177 - CONFIG_SYS_CCSRBAR:
4178 Virtual address of CCSR. On a 32-bit build, this is typically
4179 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4181 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4182 for cross-platform code that uses that macro instead.
4184 - CONFIG_SYS_CCSRBAR_PHYS:
4185 Physical address of CCSR. CCSR can be relocated to a new
4186 physical address, if desired. In this case, this macro should
4187 be set to that address. Otherwise, it should be set to the
4188 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4189 is typically relocated on 36-bit builds. It is recommended
4190 that this macro be defined via the _HIGH and _LOW macros:
4192 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4193 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4195 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4196 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4197 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4198 used in assembly code, so it must not contain typecasts or
4199 integer size suffixes (e.g. "ULL").
4201 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4202 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4203 used in assembly code, so it must not contain typecasts or
4204 integer size suffixes (e.g. "ULL").
4206 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4207 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4208 forced to a value that ensures that CCSR is not relocated.
4210 - Floppy Disk Support:
4211 CONFIG_SYS_FDC_DRIVE_NUMBER
4213 the default drive number (default value 0)
4215 CONFIG_SYS_ISA_IO_STRIDE
4217 defines the spacing between FDC chipset registers
4220 CONFIG_SYS_ISA_IO_OFFSET
4222 defines the offset of register from address. It
4223 depends on which part of the data bus is connected to
4224 the FDC chipset. (default value 0)
4226 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4227 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4230 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4231 fdc_hw_init() is called at the beginning of the FDC
4232 setup. fdc_hw_init() must be provided by the board
4233 source code. It is used to make hardware dependant
4237 Most IDE controllers were designed to be connected with PCI
4238 interface. Only few of them were designed for AHB interface.
4239 When software is doing ATA command and data transfer to
4240 IDE devices through IDE-AHB controller, some additional
4241 registers accessing to these kind of IDE-AHB controller
4244 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4245 DO NOT CHANGE unless you know exactly what you're
4246 doing! (11-4) [MPC8xx/82xx systems only]
4248 - CONFIG_SYS_INIT_RAM_ADDR:
4250 Start address of memory area that can be used for
4251 initial data and stack; please note that this must be
4252 writable memory that is working WITHOUT special
4253 initialization, i. e. you CANNOT use normal RAM which
4254 will become available only after programming the
4255 memory controller and running certain initialization
4258 U-Boot uses the following memory types:
4259 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4260 - MPC824X: data cache
4261 - PPC4xx: data cache
4263 - CONFIG_SYS_GBL_DATA_OFFSET:
4265 Offset of the initial data structure in the memory
4266 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4267 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4268 data is located at the end of the available space
4269 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4270 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4271 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4272 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4275 On the MPC824X (or other systems that use the data
4276 cache for initial memory) the address chosen for
4277 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4278 point to an otherwise UNUSED address space between
4279 the top of RAM and the start of the PCI space.
4281 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4283 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4285 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4287 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4289 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4291 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4293 - CONFIG_SYS_OR_TIMING_SDRAM:
4296 - CONFIG_SYS_MAMR_PTA:
4297 periodic timer for refresh
4299 - CONFIG_SYS_DER: Debug Event Register (37-47)
4301 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4302 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4303 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4304 CONFIG_SYS_BR1_PRELIM:
4305 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4307 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4308 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4309 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4310 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4312 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4313 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4314 Machine Mode Register and Memory Periodic Timer
4315 Prescaler definitions (SDRAM timing)
4317 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4318 enable I2C microcode relocation patch (MPC8xx);
4319 define relocation offset in DPRAM [DSP2]
4321 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4322 enable SMC microcode relocation patch (MPC8xx);
4323 define relocation offset in DPRAM [SMC1]
4325 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4326 enable SPI microcode relocation patch (MPC8xx);
4327 define relocation offset in DPRAM [SCC4]
4329 - CONFIG_SYS_USE_OSCCLK:
4330 Use OSCM clock mode on MBX8xx board. Be careful,
4331 wrong setting might damage your board. Read
4332 doc/README.MBX before setting this variable!
4334 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4335 Offset of the bootmode word in DPRAM used by post
4336 (Power On Self Tests). This definition overrides
4337 #define'd default value in commproc.h resp.
4340 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4341 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4342 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4343 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4344 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4345 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4346 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4347 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4348 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4350 - CONFIG_PCI_DISABLE_PCIE:
4351 Disable PCI-Express on systems where it is supported but not
4354 - CONFIG_PCI_ENUM_ONLY
4355 Only scan through and get the devices on the busses.
4356 Don't do any setup work, presumably because someone or
4357 something has already done it, and we don't need to do it
4358 a second time. Useful for platforms that are pre-booted
4359 by coreboot or similar.
4361 - CONFIG_PCI_INDIRECT_BRIDGE:
4362 Enable support for indirect PCI bridges.
4365 Chip has SRIO or not
4368 Board has SRIO 1 port available
4371 Board has SRIO 2 port available
4373 - CONFIG_SRIO_PCIE_BOOT_MASTER
4374 Board can support master function for Boot from SRIO and PCIE
4376 - CONFIG_SYS_SRIOn_MEM_VIRT:
4377 Virtual Address of SRIO port 'n' memory region
4379 - CONFIG_SYS_SRIOn_MEM_PHYS:
4380 Physical Address of SRIO port 'n' memory region
4382 - CONFIG_SYS_SRIOn_MEM_SIZE:
4383 Size of SRIO port 'n' memory region
4385 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4386 Defined to tell the NAND controller that the NAND chip is using
4388 Not all NAND drivers use this symbol.
4389 Example of drivers that use it:
4390 - drivers/mtd/nand/ndfc.c
4391 - drivers/mtd/nand/mxc_nand.c
4393 - CONFIG_SYS_NDFC_EBC0_CFG
4394 Sets the EBC0_CFG register for the NDFC. If not defined
4395 a default value will be used.
4398 Get DDR timing information from an I2C EEPROM. Common
4399 with pluggable memory modules such as SODIMMs
4402 I2C address of the SPD EEPROM
4404 - CONFIG_SYS_SPD_BUS_NUM
4405 If SPD EEPROM is on an I2C bus other than the first
4406 one, specify here. Note that the value must resolve
4407 to something your driver can deal with.
4409 - CONFIG_SYS_DDR_RAW_TIMING
4410 Get DDR timing information from other than SPD. Common with
4411 soldered DDR chips onboard without SPD. DDR raw timing
4412 parameters are extracted from datasheet and hard-coded into
4413 header files or board specific files.
4415 - CONFIG_FSL_DDR_INTERACTIVE
4416 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4418 - CONFIG_SYS_83XX_DDR_USES_CS0
4419 Only for 83xx systems. If specified, then DDR should
4420 be configured using CS0 and CS1 instead of CS2 and CS3.
4422 - CONFIG_ETHER_ON_FEC[12]
4423 Define to enable FEC[12] on a 8xx series processor.
4425 - CONFIG_FEC[12]_PHY
4426 Define to the hardcoded PHY address which corresponds
4427 to the given FEC; i. e.
4428 #define CONFIG_FEC1_PHY 4
4429 means that the PHY with address 4 is connected to FEC1
4431 When set to -1, means to probe for first available.
4433 - CONFIG_FEC[12]_PHY_NORXERR
4434 The PHY does not have a RXERR line (RMII only).
4435 (so program the FEC to ignore it).
4438 Enable RMII mode for all FECs.
4439 Note that this is a global option, we can't
4440 have one FEC in standard MII mode and another in RMII mode.
4442 - CONFIG_CRC32_VERIFY
4443 Add a verify option to the crc32 command.
4446 => crc32 -v <address> <count> <crc32>
4448 Where address/count indicate a memory area
4449 and crc32 is the correct crc32 which the
4453 Add the "loopw" memory command. This only takes effect if
4454 the memory commands are activated globally (CONFIG_CMD_MEM).
4457 Add the "mdc" and "mwc" memory commands. These are cyclic
4462 This command will print 4 bytes (10,11,12,13) each 500 ms.
4464 => mwc.l 100 12345678 10
4465 This command will write 12345678 to address 100 all 10 ms.
4467 This only takes effect if the memory commands are activated
4468 globally (CONFIG_CMD_MEM).
4470 - CONFIG_SKIP_LOWLEVEL_INIT
4471 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4472 low level initializations (like setting up the memory
4473 controller) are omitted and/or U-Boot does not
4474 relocate itself into RAM.
4476 Normally this variable MUST NOT be defined. The only
4477 exception is when U-Boot is loaded (to RAM) by some
4478 other boot loader or by a debugger which performs
4479 these initializations itself.
4482 Modifies the behaviour of start.S when compiling a loader
4483 that is executed before the actual U-Boot. E.g. when
4484 compiling a NAND SPL.
4487 Modifies the behaviour of start.S when compiling a loader
4488 that is executed after the SPL and before the actual U-Boot.
4489 It is loaded by the SPL.
4491 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4492 Only for 85xx systems. If this variable is specified, the section
4493 .resetvec is not kept and the section .bootpg is placed in the
4494 previous 4k of the .text section.
4496 - CONFIG_ARCH_MAP_SYSMEM
4497 Generally U-Boot (and in particular the md command) uses
4498 effective address. It is therefore not necessary to regard
4499 U-Boot address as virtual addresses that need to be translated
4500 to physical addresses. However, sandbox requires this, since
4501 it maintains its own little RAM buffer which contains all
4502 addressable memory. This option causes some memory accesses
4503 to be mapped through map_sysmem() / unmap_sysmem().
4505 - CONFIG_USE_ARCH_MEMCPY
4506 CONFIG_USE_ARCH_MEMSET
4507 If these options are used a optimized version of memcpy/memset will
4508 be used if available. These functions may be faster under some
4509 conditions but may increase the binary size.
4511 - CONFIG_X86_RESET_VECTOR
4512 If defined, the x86 reset vector code is included. This is not
4513 needed when U-Boot is running from Coreboot.
4516 Defines the MPU clock speed (in MHz).
4518 NOTE : currently only supported on AM335x platforms.
4520 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4521 Enables the RTC32K OSC on AM33xx based plattforms
4523 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4524 Option to disable subpage write in NAND driver
4525 driver that uses this:
4526 drivers/mtd/nand/davinci_nand.c
4528 Freescale QE/FMAN Firmware Support:
4529 -----------------------------------
4531 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4532 loading of "firmware", which is encoded in the QE firmware binary format.
4533 This firmware often needs to be loaded during U-Boot booting, so macros
4534 are used to identify the storage device (NOR flash, SPI, etc) and the address
4537 - CONFIG_SYS_FMAN_FW_ADDR
4538 The address in the storage device where the FMAN microcode is located. The
4539 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4542 - CONFIG_SYS_QE_FW_ADDR
4543 The address in the storage device where the QE microcode is located. The
4544 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4547 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4548 The maximum possible size of the firmware. The firmware binary format
4549 has a field that specifies the actual size of the firmware, but it
4550 might not be possible to read any part of the firmware unless some
4551 local storage is allocated to hold the entire firmware first.
4553 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4554 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4555 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4556 virtual address in NOR flash.
4558 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4559 Specifies that QE/FMAN firmware is located in NAND flash.
4560 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4562 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4563 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4564 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4566 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4567 Specifies that QE/FMAN firmware is located on the primary SPI
4568 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4570 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4571 Specifies that QE/FMAN firmware is located in the remote (master)
4572 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4573 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4574 window->master inbound window->master LAW->the ucode address in
4575 master's memory space.
4577 Building the Software:
4578 ======================
4580 Building U-Boot has been tested in several native build environments
4581 and in many different cross environments. Of course we cannot support
4582 all possibly existing versions of cross development tools in all
4583 (potentially obsolete) versions. In case of tool chain problems we
4584 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4585 which is extensively used to build and test U-Boot.
4587 If you are not using a native environment, it is assumed that you
4588 have GNU cross compiling tools available in your path. In this case,
4589 you must set the environment variable CROSS_COMPILE in your shell.
4590 Note that no changes to the Makefile or any other source files are
4591 necessary. For example using the ELDK on a 4xx CPU, please enter:
4593 $ CROSS_COMPILE=ppc_4xx-
4594 $ export CROSS_COMPILE
4596 Note: If you wish to generate Windows versions of the utilities in
4597 the tools directory you can use the MinGW toolchain
4598 (http://www.mingw.org). Set your HOST tools to the MinGW
4599 toolchain and execute 'make tools'. For example:
4601 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4603 Binaries such as tools/mkimage.exe will be created which can
4604 be executed on computers running Windows.
4606 U-Boot is intended to be simple to build. After installing the
4607 sources you must configure U-Boot for one specific board type. This
4612 where "NAME_config" is the name of one of the existing configu-
4613 rations; see boards.cfg for supported names.
4615 Note: for some board special configuration names may exist; check if
4616 additional information is available from the board vendor; for
4617 instance, the TQM823L systems are available without (standard)
4618 or with LCD support. You can select such additional "features"
4619 when choosing the configuration, i. e.
4622 - will configure for a plain TQM823L, i. e. no LCD support
4624 make TQM823L_LCD_config
4625 - will configure for a TQM823L with U-Boot console on LCD
4630 Finally, type "make all", and you should get some working U-Boot
4631 images ready for download to / installation on your system:
4633 - "u-boot.bin" is a raw binary image
4634 - "u-boot" is an image in ELF binary format
4635 - "u-boot.srec" is in Motorola S-Record format
4637 By default the build is performed locally and the objects are saved
4638 in the source directory. One of the two methods can be used to change
4639 this behavior and build U-Boot to some external directory:
4641 1. Add O= to the make command line invocations:
4643 make O=/tmp/build distclean
4644 make O=/tmp/build NAME_config
4645 make O=/tmp/build all
4647 2. Set environment variable BUILD_DIR to point to the desired location:
4649 export BUILD_DIR=/tmp/build
4654 Note that the command line "O=" setting overrides the BUILD_DIR environment
4658 Please be aware that the Makefiles assume you are using GNU make, so
4659 for instance on NetBSD you might need to use "gmake" instead of
4663 If the system board that you have is not listed, then you will need
4664 to port U-Boot to your hardware platform. To do this, follow these
4667 1. Add a new configuration option for your board to the toplevel
4668 "boards.cfg" file, using the existing entries as examples.
4669 Follow the instructions there to keep the boards in order.
4670 2. Create a new directory to hold your board specific code. Add any
4671 files you need. In your board directory, you will need at least
4672 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4673 3. Create a new configuration file "include/configs/<board>.h" for
4675 3. If you're porting U-Boot to a new CPU, then also create a new
4676 directory to hold your CPU specific code. Add any files you need.
4677 4. Run "make <board>_config" with your new name.
4678 5. Type "make", and you should get a working "u-boot.srec" file
4679 to be installed on your target system.
4680 6. Debug and solve any problems that might arise.
4681 [Of course, this last step is much harder than it sounds.]
4684 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4685 ==============================================================
4687 If you have modified U-Boot sources (for instance added a new board
4688 or support for new devices, a new CPU, etc.) you are expected to
4689 provide feedback to the other developers. The feedback normally takes
4690 the form of a "patch", i. e. a context diff against a certain (latest
4691 official or latest in the git repository) version of U-Boot sources.
4693 But before you submit such a patch, please verify that your modifi-
4694 cation did not break existing code. At least make sure that *ALL* of
4695 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4696 just run the "MAKEALL" script, which will configure and build U-Boot
4697 for ALL supported system. Be warned, this will take a while. You can
4698 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4699 environment variable to the script, i. e. to use the ELDK cross tools
4702 CROSS_COMPILE=ppc_8xx- MAKEALL
4704 or to build on a native PowerPC system you can type
4706 CROSS_COMPILE=' ' MAKEALL
4708 When using the MAKEALL script, the default behaviour is to build
4709 U-Boot in the source directory. This location can be changed by
4710 setting the BUILD_DIR environment variable. Also, for each target
4711 built, the MAKEALL script saves two log files (<target>.ERR and
4712 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4713 location can be changed by setting the MAKEALL_LOGDIR environment
4714 variable. For example:
4716 export BUILD_DIR=/tmp/build
4717 export MAKEALL_LOGDIR=/tmp/log
4718 CROSS_COMPILE=ppc_8xx- MAKEALL
4720 With the above settings build objects are saved in the /tmp/build,
4721 log files are saved in the /tmp/log and the source tree remains clean
4722 during the whole build process.
4725 See also "U-Boot Porting Guide" below.
4728 Monitor Commands - Overview:
4729 ============================
4731 go - start application at address 'addr'
4732 run - run commands in an environment variable
4733 bootm - boot application image from memory
4734 bootp - boot image via network using BootP/TFTP protocol
4735 bootz - boot zImage from memory
4736 tftpboot- boot image via network using TFTP protocol
4737 and env variables "ipaddr" and "serverip"
4738 (and eventually "gatewayip")
4739 tftpput - upload a file via network using TFTP protocol
4740 rarpboot- boot image via network using RARP/TFTP protocol
4741 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4742 loads - load S-Record file over serial line
4743 loadb - load binary file over serial line (kermit mode)
4745 mm - memory modify (auto-incrementing)
4746 nm - memory modify (constant address)
4747 mw - memory write (fill)
4749 cmp - memory compare
4750 crc32 - checksum calculation
4751 i2c - I2C sub-system
4752 sspi - SPI utility commands
4753 base - print or set address offset
4754 printenv- print environment variables
4755 setenv - set environment variables
4756 saveenv - save environment variables to persistent storage
4757 protect - enable or disable FLASH write protection
4758 erase - erase FLASH memory
4759 flinfo - print FLASH memory information
4760 nand - NAND memory operations (see doc/README.nand)
4761 bdinfo - print Board Info structure
4762 iminfo - print header information for application image
4763 coninfo - print console devices and informations
4764 ide - IDE sub-system
4765 loop - infinite loop on address range
4766 loopw - infinite write loop on address range
4767 mtest - simple RAM test
4768 icache - enable or disable instruction cache
4769 dcache - enable or disable data cache
4770 reset - Perform RESET of the CPU
4771 echo - echo args to console
4772 version - print monitor version
4773 help - print online help
4774 ? - alias for 'help'
4777 Monitor Commands - Detailed Description:
4778 ========================================
4782 For now: just type "help <command>".
4785 Environment Variables:
4786 ======================
4788 U-Boot supports user configuration using Environment Variables which
4789 can be made persistent by saving to Flash memory.
4791 Environment Variables are set using "setenv", printed using
4792 "printenv", and saved to Flash using "saveenv". Using "setenv"
4793 without a value can be used to delete a variable from the
4794 environment. As long as you don't save the environment you are
4795 working with an in-memory copy. In case the Flash area containing the
4796 environment is erased by accident, a default environment is provided.
4798 Some configuration options can be set using Environment Variables.
4800 List of environment variables (most likely not complete):
4802 baudrate - see CONFIG_BAUDRATE
4804 bootdelay - see CONFIG_BOOTDELAY
4806 bootcmd - see CONFIG_BOOTCOMMAND
4808 bootargs - Boot arguments when booting an RTOS image
4810 bootfile - Name of the image to load with TFTP
4812 bootm_low - Memory range available for image processing in the bootm
4813 command can be restricted. This variable is given as
4814 a hexadecimal number and defines lowest address allowed
4815 for use by the bootm command. See also "bootm_size"
4816 environment variable. Address defined by "bootm_low" is
4817 also the base of the initial memory mapping for the Linux
4818 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4821 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4822 This variable is given as a hexadecimal number and it
4823 defines the size of the memory region starting at base
4824 address bootm_low that is accessible by the Linux kernel
4825 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4826 as the default value if it is defined, and bootm_size is
4829 bootm_size - Memory range available for image processing in the bootm
4830 command can be restricted. This variable is given as
4831 a hexadecimal number and defines the size of the region
4832 allowed for use by the bootm command. See also "bootm_low"
4833 environment variable.
4835 updatefile - Location of the software update file on a TFTP server, used
4836 by the automatic software update feature. Please refer to
4837 documentation in doc/README.update for more details.
4839 autoload - if set to "no" (any string beginning with 'n'),
4840 "bootp" will just load perform a lookup of the
4841 configuration from the BOOTP server, but not try to
4842 load any image using TFTP
4844 autostart - if set to "yes", an image loaded using the "bootp",
4845 "rarpboot", "tftpboot" or "diskboot" commands will
4846 be automatically started (by internally calling
4849 If set to "no", a standalone image passed to the
4850 "bootm" command will be copied to the load address
4851 (and eventually uncompressed), but NOT be started.
4852 This can be used to load and uncompress arbitrary
4855 fdt_high - if set this restricts the maximum address that the
4856 flattened device tree will be copied into upon boot.
4857 For example, if you have a system with 1 GB memory
4858 at physical address 0x10000000, while Linux kernel
4859 only recognizes the first 704 MB as low memory, you
4860 may need to set fdt_high as 0x3C000000 to have the
4861 device tree blob be copied to the maximum address
4862 of the 704 MB low memory, so that Linux kernel can
4863 access it during the boot procedure.
4865 If this is set to the special value 0xFFFFFFFF then
4866 the fdt will not be copied at all on boot. For this
4867 to work it must reside in writable memory, have
4868 sufficient padding on the end of it for u-boot to
4869 add the information it needs into it, and the memory
4870 must be accessible by the kernel.
4872 fdtcontroladdr- if set this is the address of the control flattened
4873 device tree used by U-Boot when CONFIG_OF_CONTROL is
4876 i2cfast - (PPC405GP|PPC405EP only)
4877 if set to 'y' configures Linux I2C driver for fast
4878 mode (400kHZ). This environment variable is used in
4879 initialization code. So, for changes to be effective
4880 it must be saved and board must be reset.
4882 initrd_high - restrict positioning of initrd images:
4883 If this variable is not set, initrd images will be
4884 copied to the highest possible address in RAM; this
4885 is usually what you want since it allows for
4886 maximum initrd size. If for some reason you want to
4887 make sure that the initrd image is loaded below the
4888 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4889 variable to a value of "no" or "off" or "0".
4890 Alternatively, you can set it to a maximum upper
4891 address to use (U-Boot will still check that it
4892 does not overwrite the U-Boot stack and data).
4894 For instance, when you have a system with 16 MB
4895 RAM, and want to reserve 4 MB from use by Linux,
4896 you can do this by adding "mem=12M" to the value of
4897 the "bootargs" variable. However, now you must make
4898 sure that the initrd image is placed in the first
4899 12 MB as well - this can be done with
4901 setenv initrd_high 00c00000
4903 If you set initrd_high to 0xFFFFFFFF, this is an
4904 indication to U-Boot that all addresses are legal
4905 for the Linux kernel, including addresses in flash
4906 memory. In this case U-Boot will NOT COPY the
4907 ramdisk at all. This may be useful to reduce the
4908 boot time on your system, but requires that this
4909 feature is supported by your Linux kernel.
4911 ipaddr - IP address; needed for tftpboot command
4913 loadaddr - Default load address for commands like "bootp",
4914 "rarpboot", "tftpboot", "loadb" or "diskboot"
4916 loads_echo - see CONFIG_LOADS_ECHO
4918 serverip - TFTP server IP address; needed for tftpboot command
4920 bootretry - see CONFIG_BOOT_RETRY_TIME
4922 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4924 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4926 ethprime - controls which interface is used first.
4928 ethact - controls which interface is currently active.
4929 For example you can do the following
4931 => setenv ethact FEC
4932 => ping 192.168.0.1 # traffic sent on FEC
4933 => setenv ethact SCC
4934 => ping 10.0.0.1 # traffic sent on SCC
4936 ethrotate - When set to "no" U-Boot does not go through all
4937 available network interfaces.
4938 It just stays at the currently selected interface.
4940 netretry - When set to "no" each network operation will
4941 either succeed or fail without retrying.
4942 When set to "once" the network operation will
4943 fail when all the available network interfaces
4944 are tried once without success.
4945 Useful on scripts which control the retry operation
4948 npe_ucode - set load address for the NPE microcode
4950 silent_linux - If set then linux will be told to boot silently, by
4951 changing the console to be empty. If "yes" it will be
4952 made silent. If "no" it will not be made silent. If
4953 unset, then it will be made silent if the U-Boot console
4956 tftpsrcport - If this is set, the value is used for TFTP's
4959 tftpdstport - If this is set, the value is used for TFTP's UDP
4960 destination port instead of the Well Know Port 69.
4962 tftpblocksize - Block size to use for TFTP transfers; if not set,
4963 we use the TFTP server's default block size
4965 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4966 seconds, minimum value is 1000 = 1 second). Defines
4967 when a packet is considered to be lost so it has to
4968 be retransmitted. The default is 5000 = 5 seconds.
4969 Lowering this value may make downloads succeed
4970 faster in networks with high packet loss rates or
4971 with unreliable TFTP servers.
4973 vlan - When set to a value < 4095 the traffic over
4974 Ethernet is encapsulated/received over 802.1q
4977 The following image location variables contain the location of images
4978 used in booting. The "Image" column gives the role of the image and is
4979 not an environment variable name. The other columns are environment
4980 variable names. "File Name" gives the name of the file on a TFTP
4981 server, "RAM Address" gives the location in RAM the image will be
4982 loaded to, and "Flash Location" gives the image's address in NOR
4983 flash or offset in NAND flash.
4985 *Note* - these variables don't have to be defined for all boards, some
4986 boards currenlty use other variables for these purposes, and some
4987 boards use these variables for other purposes.
4989 Image File Name RAM Address Flash Location
4990 ----- --------- ----------- --------------
4991 u-boot u-boot u-boot_addr_r u-boot_addr
4992 Linux kernel bootfile kernel_addr_r kernel_addr
4993 device tree blob fdtfile fdt_addr_r fdt_addr
4994 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4996 The following environment variables may be used and automatically
4997 updated by the network boot commands ("bootp" and "rarpboot"),
4998 depending the information provided by your boot server:
5000 bootfile - see above
5001 dnsip - IP address of your Domain Name Server
5002 dnsip2 - IP address of your secondary Domain Name Server
5003 gatewayip - IP address of the Gateway (Router) to use
5004 hostname - Target hostname
5006 netmask - Subnet Mask
5007 rootpath - Pathname of the root filesystem on the NFS server
5008 serverip - see above
5011 There are two special Environment Variables:
5013 serial# - contains hardware identification information such
5014 as type string and/or serial number
5015 ethaddr - Ethernet address
5017 These variables can be set only once (usually during manufacturing of
5018 the board). U-Boot refuses to delete or overwrite these variables
5019 once they have been set once.
5022 Further special Environment Variables:
5024 ver - Contains the U-Boot version string as printed
5025 with the "version" command. This variable is
5026 readonly (see CONFIG_VERSION_VARIABLE).
5029 Please note that changes to some configuration parameters may take
5030 only effect after the next boot (yes, that's just like Windoze :-).
5033 Callback functions for environment variables:
5034 ---------------------------------------------
5036 For some environment variables, the behavior of u-boot needs to change
5037 when their values are changed. This functionailty allows functions to
5038 be associated with arbitrary variables. On creation, overwrite, or
5039 deletion, the callback will provide the opportunity for some side
5040 effect to happen or for the change to be rejected.
5042 The callbacks are named and associated with a function using the
5043 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5045 These callbacks are associated with variables in one of two ways. The
5046 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5047 in the board configuration to a string that defines a list of
5048 associations. The list must be in the following format:
5050 entry = variable_name[:callback_name]
5053 If the callback name is not specified, then the callback is deleted.
5054 Spaces are also allowed anywhere in the list.
5056 Callbacks can also be associated by defining the ".callbacks" variable
5057 with the same list format above. Any association in ".callbacks" will
5058 override any association in the static list. You can define
5059 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5060 ".callbacks" envirnoment variable in the default or embedded environment.
5063 Command Line Parsing:
5064 =====================
5066 There are two different command line parsers available with U-Boot:
5067 the old "simple" one, and the much more powerful "hush" shell:
5069 Old, simple command line parser:
5070 --------------------------------
5072 - supports environment variables (through setenv / saveenv commands)
5073 - several commands on one line, separated by ';'
5074 - variable substitution using "... ${name} ..." syntax
5075 - special characters ('$', ';') can be escaped by prefixing with '\',
5077 setenv bootcmd bootm \${address}
5078 - You can also escape text by enclosing in single apostrophes, for example:
5079 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5084 - similar to Bourne shell, with control structures like
5085 if...then...else...fi, for...do...done; while...do...done,
5086 until...do...done, ...
5087 - supports environment ("global") variables (through setenv / saveenv
5088 commands) and local shell variables (through standard shell syntax
5089 "name=value"); only environment variables can be used with "run"
5095 (1) If a command line (or an environment variable executed by a "run"
5096 command) contains several commands separated by semicolon, and
5097 one of these commands fails, then the remaining commands will be
5100 (2) If you execute several variables with one call to run (i. e.
5101 calling run with a list of variables as arguments), any failing
5102 command will cause "run" to terminate, i. e. the remaining
5103 variables are not executed.
5105 Note for Redundant Ethernet Interfaces:
5106 =======================================
5108 Some boards come with redundant Ethernet interfaces; U-Boot supports
5109 such configurations and is capable of automatic selection of a
5110 "working" interface when needed. MAC assignment works as follows:
5112 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5113 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5114 "eth1addr" (=>eth1), "eth2addr", ...
5116 If the network interface stores some valid MAC address (for instance
5117 in SROM), this is used as default address if there is NO correspon-
5118 ding setting in the environment; if the corresponding environment
5119 variable is set, this overrides the settings in the card; that means:
5121 o If the SROM has a valid MAC address, and there is no address in the
5122 environment, the SROM's address is used.
5124 o If there is no valid address in the SROM, and a definition in the
5125 environment exists, then the value from the environment variable is
5128 o If both the SROM and the environment contain a MAC address, and
5129 both addresses are the same, this MAC address is used.
5131 o If both the SROM and the environment contain a MAC address, and the
5132 addresses differ, the value from the environment is used and a
5135 o If neither SROM nor the environment contain a MAC address, an error
5138 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5139 will be programmed into hardware as part of the initialization process. This
5140 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5141 The naming convention is as follows:
5142 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5147 U-Boot is capable of booting (and performing other auxiliary operations on)
5148 images in two formats:
5150 New uImage format (FIT)
5151 -----------------------
5153 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5154 to Flattened Device Tree). It allows the use of images with multiple
5155 components (several kernels, ramdisks, etc.), with contents protected by
5156 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5162 Old image format is based on binary files which can be basically anything,
5163 preceded by a special header; see the definitions in include/image.h for
5164 details; basically, the header defines the following image properties:
5166 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5167 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5168 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5169 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5171 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5172 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5173 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5174 * Compression Type (uncompressed, gzip, bzip2)
5180 The header is marked by a special Magic Number, and both the header
5181 and the data portions of the image are secured against corruption by
5188 Although U-Boot should support any OS or standalone application
5189 easily, the main focus has always been on Linux during the design of
5192 U-Boot includes many features that so far have been part of some
5193 special "boot loader" code within the Linux kernel. Also, any
5194 "initrd" images to be used are no longer part of one big Linux image;
5195 instead, kernel and "initrd" are separate images. This implementation
5196 serves several purposes:
5198 - the same features can be used for other OS or standalone
5199 applications (for instance: using compressed images to reduce the
5200 Flash memory footprint)
5202 - it becomes much easier to port new Linux kernel versions because
5203 lots of low-level, hardware dependent stuff are done by U-Boot
5205 - the same Linux kernel image can now be used with different "initrd"
5206 images; of course this also means that different kernel images can
5207 be run with the same "initrd". This makes testing easier (you don't
5208 have to build a new "zImage.initrd" Linux image when you just
5209 change a file in your "initrd"). Also, a field-upgrade of the
5210 software is easier now.
5216 Porting Linux to U-Boot based systems:
5217 ---------------------------------------
5219 U-Boot cannot save you from doing all the necessary modifications to
5220 configure the Linux device drivers for use with your target hardware
5221 (no, we don't intend to provide a full virtual machine interface to
5224 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5226 Just make sure your machine specific header file (for instance
5227 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5228 Information structure as we define in include/asm-<arch>/u-boot.h,
5229 and make sure that your definition of IMAP_ADDR uses the same value
5230 as your U-Boot configuration in CONFIG_SYS_IMMR.
5233 Configuring the Linux kernel:
5234 -----------------------------
5236 No specific requirements for U-Boot. Make sure you have some root
5237 device (initial ramdisk, NFS) for your target system.
5240 Building a Linux Image:
5241 -----------------------
5243 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5244 not used. If you use recent kernel source, a new build target
5245 "uImage" will exist which automatically builds an image usable by
5246 U-Boot. Most older kernels also have support for a "pImage" target,
5247 which was introduced for our predecessor project PPCBoot and uses a
5248 100% compatible format.
5257 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5258 encapsulate a compressed Linux kernel image with header information,
5259 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5261 * build a standard "vmlinux" kernel image (in ELF binary format):
5263 * convert the kernel into a raw binary image:
5265 ${CROSS_COMPILE}-objcopy -O binary \
5266 -R .note -R .comment \
5267 -S vmlinux linux.bin
5269 * compress the binary image:
5273 * package compressed binary image for U-Boot:
5275 mkimage -A ppc -O linux -T kernel -C gzip \
5276 -a 0 -e 0 -n "Linux Kernel Image" \
5277 -d linux.bin.gz uImage
5280 The "mkimage" tool can also be used to create ramdisk images for use
5281 with U-Boot, either separated from the Linux kernel image, or
5282 combined into one file. "mkimage" encapsulates the images with a 64
5283 byte header containing information about target architecture,
5284 operating system, image type, compression method, entry points, time
5285 stamp, CRC32 checksums, etc.
5287 "mkimage" can be called in two ways: to verify existing images and
5288 print the header information, or to build new images.
5290 In the first form (with "-l" option) mkimage lists the information
5291 contained in the header of an existing U-Boot image; this includes
5292 checksum verification:
5294 tools/mkimage -l image
5295 -l ==> list image header information
5297 The second form (with "-d" option) is used to build a U-Boot image
5298 from a "data file" which is used as image payload:
5300 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5301 -n name -d data_file image
5302 -A ==> set architecture to 'arch'
5303 -O ==> set operating system to 'os'
5304 -T ==> set image type to 'type'
5305 -C ==> set compression type 'comp'
5306 -a ==> set load address to 'addr' (hex)
5307 -e ==> set entry point to 'ep' (hex)
5308 -n ==> set image name to 'name'
5309 -d ==> use image data from 'datafile'
5311 Right now, all Linux kernels for PowerPC systems use the same load
5312 address (0x00000000), but the entry point address depends on the
5315 - 2.2.x kernels have the entry point at 0x0000000C,
5316 - 2.3.x and later kernels have the entry point at 0x00000000.
5318 So a typical call to build a U-Boot image would read:
5320 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5321 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5322 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5323 > examples/uImage.TQM850L
5324 Image Name: 2.4.4 kernel for TQM850L
5325 Created: Wed Jul 19 02:34:59 2000
5326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5327 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5328 Load Address: 0x00000000
5329 Entry Point: 0x00000000
5331 To verify the contents of the image (or check for corruption):
5333 -> tools/mkimage -l examples/uImage.TQM850L
5334 Image Name: 2.4.4 kernel for TQM850L
5335 Created: Wed Jul 19 02:34:59 2000
5336 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5337 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5338 Load Address: 0x00000000
5339 Entry Point: 0x00000000
5341 NOTE: for embedded systems where boot time is critical you can trade
5342 speed for memory and install an UNCOMPRESSED image instead: this
5343 needs more space in Flash, but boots much faster since it does not
5344 need to be uncompressed:
5346 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5347 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5348 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5349 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5350 > examples/uImage.TQM850L-uncompressed
5351 Image Name: 2.4.4 kernel for TQM850L
5352 Created: Wed Jul 19 02:34:59 2000
5353 Image Type: PowerPC Linux Kernel Image (uncompressed)
5354 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5355 Load Address: 0x00000000
5356 Entry Point: 0x00000000
5359 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5360 when your kernel is intended to use an initial ramdisk:
5362 -> tools/mkimage -n 'Simple Ramdisk Image' \
5363 > -A ppc -O linux -T ramdisk -C gzip \
5364 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5365 Image Name: Simple Ramdisk Image
5366 Created: Wed Jan 12 14:01:50 2000
5367 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5368 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5369 Load Address: 0x00000000
5370 Entry Point: 0x00000000
5372 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5373 option performs the converse operation of the mkimage's second form (the "-d"
5374 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5377 tools/dumpimage -i image -p position data_file
5378 -i ==> extract from the 'image' a specific 'data_file', \
5379 indexed by 'position'
5382 Installing a Linux Image:
5383 -------------------------
5385 To downloading a U-Boot image over the serial (console) interface,
5386 you must convert the image to S-Record format:
5388 objcopy -I binary -O srec examples/image examples/image.srec
5390 The 'objcopy' does not understand the information in the U-Boot
5391 image header, so the resulting S-Record file will be relative to
5392 address 0x00000000. To load it to a given address, you need to
5393 specify the target address as 'offset' parameter with the 'loads'
5396 Example: install the image to address 0x40100000 (which on the
5397 TQM8xxL is in the first Flash bank):
5399 => erase 40100000 401FFFFF
5405 ## Ready for S-Record download ...
5406 ~>examples/image.srec
5407 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5409 15989 15990 15991 15992
5410 [file transfer complete]
5412 ## Start Addr = 0x00000000
5415 You can check the success of the download using the 'iminfo' command;
5416 this includes a checksum verification so you can be sure no data
5417 corruption happened:
5421 ## Checking Image at 40100000 ...
5422 Image Name: 2.2.13 for initrd on TQM850L
5423 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5424 Data Size: 335725 Bytes = 327 kB = 0 MB
5425 Load Address: 00000000
5426 Entry Point: 0000000c
5427 Verifying Checksum ... OK
5433 The "bootm" command is used to boot an application that is stored in
5434 memory (RAM or Flash). In case of a Linux kernel image, the contents
5435 of the "bootargs" environment variable is passed to the kernel as
5436 parameters. You can check and modify this variable using the
5437 "printenv" and "setenv" commands:
5440 => printenv bootargs
5441 bootargs=root=/dev/ram
5443 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5445 => printenv bootargs
5446 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5449 ## Booting Linux kernel at 40020000 ...
5450 Image Name: 2.2.13 for NFS on TQM850L
5451 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5452 Data Size: 381681 Bytes = 372 kB = 0 MB
5453 Load Address: 00000000
5454 Entry Point: 0000000c
5455 Verifying Checksum ... OK
5456 Uncompressing Kernel Image ... OK
5457 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
5458 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5459 time_init: decrementer frequency = 187500000/60
5460 Calibrating delay loop... 49.77 BogoMIPS
5461 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5464 If you want to boot a Linux kernel with initial RAM disk, you pass
5465 the memory addresses of both the kernel and the initrd image (PPBCOOT
5466 format!) to the "bootm" command:
5468 => imi 40100000 40200000
5470 ## Checking Image at 40100000 ...
5471 Image Name: 2.2.13 for initrd on TQM850L
5472 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5473 Data Size: 335725 Bytes = 327 kB = 0 MB
5474 Load Address: 00000000
5475 Entry Point: 0000000c
5476 Verifying Checksum ... OK
5478 ## Checking Image at 40200000 ...
5479 Image Name: Simple Ramdisk Image
5480 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5481 Data Size: 566530 Bytes = 553 kB = 0 MB
5482 Load Address: 00000000
5483 Entry Point: 00000000
5484 Verifying Checksum ... OK
5486 => bootm 40100000 40200000
5487 ## Booting Linux kernel at 40100000 ...
5488 Image Name: 2.2.13 for initrd on TQM850L
5489 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5490 Data Size: 335725 Bytes = 327 kB = 0 MB
5491 Load Address: 00000000
5492 Entry Point: 0000000c
5493 Verifying Checksum ... OK
5494 Uncompressing Kernel Image ... OK
5495 ## Loading RAMDisk Image at 40200000 ...
5496 Image Name: Simple Ramdisk Image
5497 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5498 Data Size: 566530 Bytes = 553 kB = 0 MB
5499 Load Address: 00000000
5500 Entry Point: 00000000
5501 Verifying Checksum ... OK
5502 Loading Ramdisk ... OK
5503 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
5504 Boot arguments: root=/dev/ram
5505 time_init: decrementer frequency = 187500000/60
5506 Calibrating delay loop... 49.77 BogoMIPS
5508 RAMDISK: Compressed image found at block 0
5509 VFS: Mounted root (ext2 filesystem).
5513 Boot Linux and pass a flat device tree:
5516 First, U-Boot must be compiled with the appropriate defines. See the section
5517 titled "Linux Kernel Interface" above for a more in depth explanation. The
5518 following is an example of how to start a kernel and pass an updated
5524 oft=oftrees/mpc8540ads.dtb
5525 => tftp $oftaddr $oft
5526 Speed: 1000, full duplex
5528 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5529 Filename 'oftrees/mpc8540ads.dtb'.
5530 Load address: 0x300000
5533 Bytes transferred = 4106 (100a hex)
5534 => tftp $loadaddr $bootfile
5535 Speed: 1000, full duplex
5537 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5539 Load address: 0x200000
5540 Loading:############
5542 Bytes transferred = 1029407 (fb51f hex)
5547 => bootm $loadaddr - $oftaddr
5548 ## Booting image at 00200000 ...
5549 Image Name: Linux-2.6.17-dirty
5550 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5551 Data Size: 1029343 Bytes = 1005.2 kB
5552 Load Address: 00000000
5553 Entry Point: 00000000
5554 Verifying Checksum ... OK
5555 Uncompressing Kernel Image ... OK
5556 Booting using flat device tree at 0x300000
5557 Using MPC85xx ADS machine description
5558 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5562 More About U-Boot Image Types:
5563 ------------------------------
5565 U-Boot supports the following image types:
5567 "Standalone Programs" are directly runnable in the environment
5568 provided by U-Boot; it is expected that (if they behave
5569 well) you can continue to work in U-Boot after return from
5570 the Standalone Program.
5571 "OS Kernel Images" are usually images of some Embedded OS which
5572 will take over control completely. Usually these programs
5573 will install their own set of exception handlers, device
5574 drivers, set up the MMU, etc. - this means, that you cannot
5575 expect to re-enter U-Boot except by resetting the CPU.
5576 "RAMDisk Images" are more or less just data blocks, and their
5577 parameters (address, size) are passed to an OS kernel that is
5579 "Multi-File Images" contain several images, typically an OS
5580 (Linux) kernel image and one or more data images like
5581 RAMDisks. This construct is useful for instance when you want
5582 to boot over the network using BOOTP etc., where the boot
5583 server provides just a single image file, but you want to get
5584 for instance an OS kernel and a RAMDisk image.
5586 "Multi-File Images" start with a list of image sizes, each
5587 image size (in bytes) specified by an "uint32_t" in network
5588 byte order. This list is terminated by an "(uint32_t)0".
5589 Immediately after the terminating 0 follow the images, one by
5590 one, all aligned on "uint32_t" boundaries (size rounded up to
5591 a multiple of 4 bytes).
5593 "Firmware Images" are binary images containing firmware (like
5594 U-Boot or FPGA images) which usually will be programmed to
5597 "Script files" are command sequences that will be executed by
5598 U-Boot's command interpreter; this feature is especially
5599 useful when you configure U-Boot to use a real shell (hush)
5600 as command interpreter.
5602 Booting the Linux zImage:
5603 -------------------------
5605 On some platforms, it's possible to boot Linux zImage. This is done
5606 using the "bootz" command. The syntax of "bootz" command is the same
5607 as the syntax of "bootm" command.
5609 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5610 kernel with raw initrd images. The syntax is slightly different, the
5611 address of the initrd must be augmented by it's size, in the following
5612 format: "<initrd addres>:<initrd size>".
5618 One of the features of U-Boot is that you can dynamically load and
5619 run "standalone" applications, which can use some resources of
5620 U-Boot like console I/O functions or interrupt services.
5622 Two simple examples are included with the sources:
5627 'examples/hello_world.c' contains a small "Hello World" Demo
5628 application; it is automatically compiled when you build U-Boot.
5629 It's configured to run at address 0x00040004, so you can play with it
5633 ## Ready for S-Record download ...
5634 ~>examples/hello_world.srec
5635 1 2 3 4 5 6 7 8 9 10 11 ...
5636 [file transfer complete]
5638 ## Start Addr = 0x00040004
5640 => go 40004 Hello World! This is a test.
5641 ## Starting application at 0x00040004 ...
5652 Hit any key to exit ...
5654 ## Application terminated, rc = 0x0
5656 Another example, which demonstrates how to register a CPM interrupt
5657 handler with the U-Boot code, can be found in 'examples/timer.c'.
5658 Here, a CPM timer is set up to generate an interrupt every second.
5659 The interrupt service routine is trivial, just printing a '.'
5660 character, but this is just a demo program. The application can be
5661 controlled by the following keys:
5663 ? - print current values og the CPM Timer registers
5664 b - enable interrupts and start timer
5665 e - stop timer and disable interrupts
5666 q - quit application
5669 ## Ready for S-Record download ...
5670 ~>examples/timer.srec
5671 1 2 3 4 5 6 7 8 9 10 11 ...
5672 [file transfer complete]
5674 ## Start Addr = 0x00040004
5677 ## Starting application at 0x00040004 ...
5680 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5683 [q, b, e, ?] Set interval 1000000 us
5686 [q, b, e, ?] ........
5687 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5690 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5693 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5696 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5698 [q, b, e, ?] ...Stopping timer
5700 [q, b, e, ?] ## Application terminated, rc = 0x0
5706 Over time, many people have reported problems when trying to use the
5707 "minicom" terminal emulation program for serial download. I (wd)
5708 consider minicom to be broken, and recommend not to use it. Under
5709 Unix, I recommend to use C-Kermit for general purpose use (and
5710 especially for kermit binary protocol download ("loadb" command), and
5711 use "cu" for S-Record download ("loads" command). See
5712 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5713 for help with kermit.
5716 Nevertheless, if you absolutely want to use it try adding this
5717 configuration to your "File transfer protocols" section:
5719 Name Program Name U/D FullScr IO-Red. Multi
5720 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5721 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5727 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5728 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5730 Building requires a cross environment; it is known to work on
5731 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5732 need gmake since the Makefiles are not compatible with BSD make).
5733 Note that the cross-powerpc package does not install include files;
5734 attempting to build U-Boot will fail because <machine/ansi.h> is
5735 missing. This file has to be installed and patched manually:
5737 # cd /usr/pkg/cross/powerpc-netbsd/include
5739 # ln -s powerpc machine
5740 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5741 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5743 Native builds *don't* work due to incompatibilities between native
5744 and U-Boot include files.
5746 Booting assumes that (the first part of) the image booted is a
5747 stage-2 loader which in turn loads and then invokes the kernel
5748 proper. Loader sources will eventually appear in the NetBSD source
5749 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5750 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5753 Implementation Internals:
5754 =========================
5756 The following is not intended to be a complete description of every
5757 implementation detail. However, it should help to understand the
5758 inner workings of U-Boot and make it easier to port it to custom
5762 Initial Stack, Global Data:
5763 ---------------------------
5765 The implementation of U-Boot is complicated by the fact that U-Boot
5766 starts running out of ROM (flash memory), usually without access to
5767 system RAM (because the memory controller is not initialized yet).
5768 This means that we don't have writable Data or BSS segments, and BSS
5769 is not initialized as zero. To be able to get a C environment working
5770 at all, we have to allocate at least a minimal stack. Implementation
5771 options for this are defined and restricted by the CPU used: Some CPU
5772 models provide on-chip memory (like the IMMR area on MPC8xx and
5773 MPC826x processors), on others (parts of) the data cache can be
5774 locked as (mis-) used as memory, etc.
5776 Chris Hallinan posted a good summary of these issues to the
5777 U-Boot mailing list:
5779 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5780 From: "Chris Hallinan" <clh@net1plus.com>
5781 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5784 Correct me if I'm wrong, folks, but the way I understand it
5785 is this: Using DCACHE as initial RAM for Stack, etc, does not
5786 require any physical RAM backing up the cache. The cleverness
5787 is that the cache is being used as a temporary supply of
5788 necessary storage before the SDRAM controller is setup. It's
5789 beyond the scope of this list to explain the details, but you
5790 can see how this works by studying the cache architecture and
5791 operation in the architecture and processor-specific manuals.
5793 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5794 is another option for the system designer to use as an
5795 initial stack/RAM area prior to SDRAM being available. Either
5796 option should work for you. Using CS 4 should be fine if your
5797 board designers haven't used it for something that would
5798 cause you grief during the initial boot! It is frequently not
5801 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5802 with your processor/board/system design. The default value
5803 you will find in any recent u-boot distribution in
5804 walnut.h should work for you. I'd set it to a value larger
5805 than your SDRAM module. If you have a 64MB SDRAM module, set
5806 it above 400_0000. Just make sure your board has no resources
5807 that are supposed to respond to that address! That code in
5808 start.S has been around a while and should work as is when
5809 you get the config right.
5814 It is essential to remember this, since it has some impact on the C
5815 code for the initialization procedures:
5817 * Initialized global data (data segment) is read-only. Do not attempt
5820 * Do not use any uninitialized global data (or implicitely initialized
5821 as zero data - BSS segment) at all - this is undefined, initiali-
5822 zation is performed later (when relocating to RAM).
5824 * Stack space is very limited. Avoid big data buffers or things like
5827 Having only the stack as writable memory limits means we cannot use
5828 normal global data to share information beween the code. But it
5829 turned out that the implementation of U-Boot can be greatly
5830 simplified by making a global data structure (gd_t) available to all
5831 functions. We could pass a pointer to this data as argument to _all_
5832 functions, but this would bloat the code. Instead we use a feature of
5833 the GCC compiler (Global Register Variables) to share the data: we
5834 place a pointer (gd) to the global data into a register which we
5835 reserve for this purpose.
5837 When choosing a register for such a purpose we are restricted by the
5838 relevant (E)ABI specifications for the current architecture, and by
5839 GCC's implementation.
5841 For PowerPC, the following registers have specific use:
5843 R2: reserved for system use
5844 R3-R4: parameter passing and return values
5845 R5-R10: parameter passing
5846 R13: small data area pointer
5850 (U-Boot also uses R12 as internal GOT pointer. r12
5851 is a volatile register so r12 needs to be reset when
5852 going back and forth between asm and C)
5854 ==> U-Boot will use R2 to hold a pointer to the global data
5856 Note: on PPC, we could use a static initializer (since the
5857 address of the global data structure is known at compile time),
5858 but it turned out that reserving a register results in somewhat
5859 smaller code - although the code savings are not that big (on
5860 average for all boards 752 bytes for the whole U-Boot image,
5861 624 text + 127 data).
5863 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5864 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5866 ==> U-Boot will use P3 to hold a pointer to the global data
5868 On ARM, the following registers are used:
5870 R0: function argument word/integer result
5871 R1-R3: function argument word
5872 R9: platform specific
5873 R10: stack limit (used only if stack checking is enabled)
5874 R11: argument (frame) pointer
5875 R12: temporary workspace
5878 R15: program counter
5880 ==> U-Boot will use R9 to hold a pointer to the global data
5882 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5884 On Nios II, the ABI is documented here:
5885 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5887 ==> U-Boot will use gp to hold a pointer to the global data
5889 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5890 to access small data sections, so gp is free.
5892 On NDS32, the following registers are used:
5894 R0-R1: argument/return
5896 R15: temporary register for assembler
5897 R16: trampoline register
5898 R28: frame pointer (FP)
5899 R29: global pointer (GP)
5900 R30: link register (LP)
5901 R31: stack pointer (SP)
5902 PC: program counter (PC)
5904 ==> U-Boot will use R10 to hold a pointer to the global data
5906 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5907 or current versions of GCC may "optimize" the code too much.
5912 U-Boot runs in system state and uses physical addresses, i.e. the
5913 MMU is not used either for address mapping nor for memory protection.
5915 The available memory is mapped to fixed addresses using the memory
5916 controller. In this process, a contiguous block is formed for each
5917 memory type (Flash, SDRAM, SRAM), even when it consists of several
5918 physical memory banks.
5920 U-Boot is installed in the first 128 kB of the first Flash bank (on
5921 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5922 booting and sizing and initializing DRAM, the code relocates itself
5923 to the upper end of DRAM. Immediately below the U-Boot code some
5924 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5925 configuration setting]. Below that, a structure with global Board
5926 Info data is placed, followed by the stack (growing downward).
5928 Additionally, some exception handler code is copied to the low 8 kB
5929 of DRAM (0x00000000 ... 0x00001FFF).
5931 So a typical memory configuration with 16 MB of DRAM could look like
5934 0x0000 0000 Exception Vector code
5937 0x0000 2000 Free for Application Use
5943 0x00FB FF20 Monitor Stack (Growing downward)
5944 0x00FB FFAC Board Info Data and permanent copy of global data
5945 0x00FC 0000 Malloc Arena
5948 0x00FE 0000 RAM Copy of Monitor Code
5949 ... eventually: LCD or video framebuffer
5950 ... eventually: pRAM (Protected RAM - unchanged by reset)
5951 0x00FF FFFF [End of RAM]
5954 System Initialization:
5955 ----------------------
5957 In the reset configuration, U-Boot starts at the reset entry point
5958 (on most PowerPC systems at address 0x00000100). Because of the reset
5959 configuration for CS0# this is a mirror of the onboard Flash memory.
5960 To be able to re-map memory U-Boot then jumps to its link address.
5961 To be able to implement the initialization code in C, a (small!)
5962 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5963 which provide such a feature like MPC8xx or MPC8260), or in a locked
5964 part of the data cache. After that, U-Boot initializes the CPU core,
5965 the caches and the SIU.
5967 Next, all (potentially) available memory banks are mapped using a
5968 preliminary mapping. For example, we put them on 512 MB boundaries
5969 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5970 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5971 programmed for SDRAM access. Using the temporary configuration, a
5972 simple memory test is run that determines the size of the SDRAM
5975 When there is more than one SDRAM bank, and the banks are of
5976 different size, the largest is mapped first. For equal size, the first
5977 bank (CS2#) is mapped first. The first mapping is always for address
5978 0x00000000, with any additional banks following immediately to create
5979 contiguous memory starting from 0.
5981 Then, the monitor installs itself at the upper end of the SDRAM area
5982 and allocates memory for use by malloc() and for the global Board
5983 Info data; also, the exception vector code is copied to the low RAM
5984 pages, and the final stack is set up.
5986 Only after this relocation will you have a "normal" C environment;
5987 until that you are restricted in several ways, mostly because you are
5988 running from ROM, and because the code will have to be relocated to a
5992 U-Boot Porting Guide:
5993 ----------------------
5995 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5999 int main(int argc, char *argv[])
6001 sighandler_t no_more_time;
6003 signal(SIGALRM, no_more_time);
6004 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6006 if (available_money > available_manpower) {
6007 Pay consultant to port U-Boot;
6011 Download latest U-Boot source;
6013 Subscribe to u-boot mailing list;
6016 email("Hi, I am new to U-Boot, how do I get started?");
6019 Read the README file in the top level directory;
6020 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6021 Read applicable doc/*.README;
6022 Read the source, Luke;
6023 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6026 if (available_money > toLocalCurrency ($2500))
6029 Add a lot of aggravation and time;
6031 if (a similar board exists) { /* hopefully... */
6032 cp -a board/<similar> board/<myboard>
6033 cp include/configs/<similar>.h include/configs/<myboard>.h
6035 Create your own board support subdirectory;
6036 Create your own board include/configs/<myboard>.h file;
6038 Edit new board/<myboard> files
6039 Edit new include/configs/<myboard>.h
6044 Add / modify source code;
6048 email("Hi, I am having problems...");
6050 Send patch file to the U-Boot email list;
6051 if (reasonable critiques)
6052 Incorporate improvements from email list code review;
6054 Defend code as written;
6060 void no_more_time (int sig)
6069 All contributions to U-Boot should conform to the Linux kernel
6070 coding style; see the file "Documentation/CodingStyle" and the script
6071 "scripts/Lindent" in your Linux kernel source directory.
6073 Source files originating from a different project (for example the
6074 MTD subsystem) are generally exempt from these guidelines and are not
6075 reformated to ease subsequent migration to newer versions of those
6078 Please note that U-Boot is implemented in C (and to some small parts in
6079 Assembler); no C++ is used, so please do not use C++ style comments (//)
6082 Please also stick to the following formatting rules:
6083 - remove any trailing white space
6084 - use TAB characters for indentation and vertical alignment, not spaces
6085 - make sure NOT to use DOS '\r\n' line feeds
6086 - do not add more than 2 consecutive empty lines to source files
6087 - do not add trailing empty lines to source files
6089 Submissions which do not conform to the standards may be returned
6090 with a request to reformat the changes.
6096 Since the number of patches for U-Boot is growing, we need to
6097 establish some rules. Submissions which do not conform to these rules
6098 may be rejected, even when they contain important and valuable stuff.
6100 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6102 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6103 see http://lists.denx.de/mailman/listinfo/u-boot
6105 When you send a patch, please include the following information with
6108 * For bug fixes: a description of the bug and how your patch fixes
6109 this bug. Please try to include a way of demonstrating that the
6110 patch actually fixes something.
6112 * For new features: a description of the feature and your
6115 * A CHANGELOG entry as plaintext (separate from the patch)
6117 * For major contributions, your entry to the CREDITS file
6119 * When you add support for a new board, don't forget to add a
6120 maintainer e-mail address to the boards.cfg file, too.
6122 * If your patch adds new configuration options, don't forget to
6123 document these in the README file.
6125 * The patch itself. If you are using git (which is *strongly*
6126 recommended) you can easily generate the patch using the
6127 "git format-patch". If you then use "git send-email" to send it to
6128 the U-Boot mailing list, you will avoid most of the common problems
6129 with some other mail clients.
6131 If you cannot use git, use "diff -purN OLD NEW". If your version of
6132 diff does not support these options, then get the latest version of
6135 The current directory when running this command shall be the parent
6136 directory of the U-Boot source tree (i. e. please make sure that
6137 your patch includes sufficient directory information for the
6140 We prefer patches as plain text. MIME attachments are discouraged,
6141 and compressed attachments must not be used.
6143 * If one logical set of modifications affects or creates several
6144 files, all these changes shall be submitted in a SINGLE patch file.
6146 * Changesets that contain different, unrelated modifications shall be
6147 submitted as SEPARATE patches, one patch per changeset.
6152 * Before sending the patch, run the MAKEALL script on your patched
6153 source tree and make sure that no errors or warnings are reported
6154 for any of the boards.
6156 * Keep your modifications to the necessary minimum: A patch
6157 containing several unrelated changes or arbitrary reformats will be
6158 returned with a request to re-formatting / split it.
6160 * If you modify existing code, make sure that your new code does not
6161 add to the memory footprint of the code ;-) Small is beautiful!
6162 When adding new features, these should compile conditionally only
6163 (using #ifdef), and the resulting code with the new feature
6164 disabled must not need more memory than the old code without your
6167 * Remember that there is a size limit of 100 kB per message on the
6168 u-boot mailing list. Bigger patches will be moderated. If they are
6169 reasonable and not too big, they will be acknowledged. But patches
6170 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob