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 - USB Device Android Fastboot support:
1563 This enables the command "fastboot" which enables the Android
1564 fastboot mode for the platform's USB device. Fastboot is a USB
1565 protocol for downloading images, flashing and device control
1566 used on Android devices.
1567 See doc/README.android-fastboot for more information.
1569 CONFIG_ANDROID_BOOT_IMAGE
1570 This enables support for booting images which use the Android
1571 image format header.
1573 CONFIG_USB_FASTBOOT_BUF_ADDR
1574 The fastboot protocol requires a large memory buffer for
1575 downloads. Define this to the starting RAM address to use for
1578 CONFIG_USB_FASTBOOT_BUF_SIZE
1579 The fastboot protocol requires a large memory buffer for
1580 downloads. This buffer should be as large as possible for a
1581 platform. Define this to the size available RAM for fastboot.
1583 - Journaling Flash filesystem support:
1584 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1585 CONFIG_JFFS2_NAND_DEV
1586 Define these for a default partition on a NAND device
1588 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1589 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1590 Define these for a default partition on a NOR device
1592 CONFIG_SYS_JFFS_CUSTOM_PART
1593 Define this to create an own partition. You have to provide a
1594 function struct part_info* jffs2_part_info(int part_num)
1596 If you define only one JFFS2 partition you may also want to
1597 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1598 to disable the command chpart. This is the default when you
1599 have not defined a custom partition
1601 - FAT(File Allocation Table) filesystem write function support:
1604 Define this to enable support for saving memory data as a
1605 file in FAT formatted partition.
1607 This will also enable the command "fatwrite" enabling the
1608 user to write files to FAT.
1610 CBFS (Coreboot Filesystem) support
1613 Define this to enable support for reading from a Coreboot
1614 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1620 Define this to enable standard (PC-Style) keyboard
1624 Standard PC keyboard driver with US (is default) and
1625 GERMAN key layout (switch via environment 'keymap=de') support.
1626 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1627 for cfb_console. Supports cursor blinking.
1630 Enables a Chrome OS keyboard using the CROS_EC interface.
1631 This uses CROS_EC to communicate with a second microcontroller
1632 which provides key scans on request.
1637 Define this to enable video support (for output to
1640 CONFIG_VIDEO_CT69000
1642 Enable Chips & Technologies 69000 Video chip
1644 CONFIG_VIDEO_SMI_LYNXEM
1645 Enable Silicon Motion SMI 712/710/810 Video chip. The
1646 video output is selected via environment 'videoout'
1647 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1650 For the CT69000 and SMI_LYNXEM drivers, videomode is
1651 selected via environment 'videomode'. Two different ways
1653 - "videomode=num" 'num' is a standard LiLo mode numbers.
1654 Following standard modes are supported (* is default):
1656 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1657 -------------+---------------------------------------------
1658 8 bits | 0x301* 0x303 0x305 0x161 0x307
1659 15 bits | 0x310 0x313 0x316 0x162 0x319
1660 16 bits | 0x311 0x314 0x317 0x163 0x31A
1661 24 bits | 0x312 0x315 0x318 ? 0x31B
1662 -------------+---------------------------------------------
1663 (i.e. setenv videomode 317; saveenv; reset;)
1665 - "videomode=bootargs" all the video parameters are parsed
1666 from the bootargs. (See drivers/video/videomodes.c)
1669 CONFIG_VIDEO_SED13806
1670 Enable Epson SED13806 driver. This driver supports 8bpp
1671 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1672 or CONFIG_VIDEO_SED13806_16BPP
1675 Enable the Freescale DIU video driver. Reference boards for
1676 SOCs that have a DIU should define this macro to enable DIU
1677 support, and should also define these other macros:
1683 CONFIG_VIDEO_SW_CURSOR
1684 CONFIG_VGA_AS_SINGLE_DEVICE
1686 CONFIG_VIDEO_BMP_LOGO
1688 The DIU driver will look for the 'video-mode' environment
1689 variable, and if defined, enable the DIU as a console during
1690 boot. See the documentation file README.video for a
1691 description of this variable.
1695 Enable the VGA video / BIOS for x86. The alternative if you
1696 are using coreboot is to use the coreboot frame buffer
1703 Define this to enable a custom keyboard support.
1704 This simply calls drv_keyboard_init() which must be
1705 defined in your board-specific files.
1706 The only board using this so far is RBC823.
1708 - LCD Support: CONFIG_LCD
1710 Define this to enable LCD support (for output to LCD
1711 display); also select one of the supported displays
1712 by defining one of these:
1716 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1718 CONFIG_NEC_NL6448AC33:
1720 NEC NL6448AC33-18. Active, color, single scan.
1722 CONFIG_NEC_NL6448BC20
1724 NEC NL6448BC20-08. 6.5", 640x480.
1725 Active, color, single scan.
1727 CONFIG_NEC_NL6448BC33_54
1729 NEC NL6448BC33-54. 10.4", 640x480.
1730 Active, color, single scan.
1734 Sharp 320x240. Active, color, single scan.
1735 It isn't 16x9, and I am not sure what it is.
1737 CONFIG_SHARP_LQ64D341
1739 Sharp LQ64D341 display, 640x480.
1740 Active, color, single scan.
1744 HLD1045 display, 640x480.
1745 Active, color, single scan.
1749 Optrex CBL50840-2 NF-FW 99 22 M5
1751 Hitachi LMG6912RPFC-00T
1755 320x240. Black & white.
1757 Normally display is black on white background; define
1758 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1760 CONFIG_LCD_ALIGNMENT
1762 Normally the LCD is page-aligned (tyically 4KB). If this is
1763 defined then the LCD will be aligned to this value instead.
1764 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1765 here, since it is cheaper to change data cache settings on
1766 a per-section basis.
1768 CONFIG_CONSOLE_SCROLL_LINES
1770 When the console need to be scrolled, this is the number of
1771 lines to scroll by. It defaults to 1. Increasing this makes
1772 the console jump but can help speed up operation when scrolling
1777 Support drawing of RLE8-compressed bitmaps on the LCD.
1781 Enables an 'i2c edid' command which can read EDID
1782 information over I2C from an attached LCD display.
1784 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1786 If this option is set, the environment is checked for
1787 a variable "splashimage". If found, the usual display
1788 of logo, copyright and system information on the LCD
1789 is suppressed and the BMP image at the address
1790 specified in "splashimage" is loaded instead. The
1791 console is redirected to the "nulldev", too. This
1792 allows for a "silent" boot where a splash screen is
1793 loaded very quickly after power-on.
1795 CONFIG_SPLASHIMAGE_GUARD
1797 If this option is set, then U-Boot will prevent the environment
1798 variable "splashimage" from being set to a problematic address
1799 (see README.displaying-bmps).
1800 This option is useful for targets where, due to alignment
1801 restrictions, an improperly aligned BMP image will cause a data
1802 abort. If you think you will not have problems with unaligned
1803 accesses (for example because your toolchain prevents them)
1804 there is no need to set this option.
1806 CONFIG_SPLASH_SCREEN_ALIGN
1808 If this option is set the splash image can be freely positioned
1809 on the screen. Environment variable "splashpos" specifies the
1810 position as "x,y". If a positive number is given it is used as
1811 number of pixel from left/top. If a negative number is given it
1812 is used as number of pixel from right/bottom. You can also
1813 specify 'm' for centering the image.
1816 setenv splashpos m,m
1817 => image at center of screen
1819 setenv splashpos 30,20
1820 => image at x = 30 and y = 20
1822 setenv splashpos -10,m
1823 => vertically centered image
1824 at x = dspWidth - bmpWidth - 9
1826 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1828 If this option is set, additionally to standard BMP
1829 images, gzipped BMP images can be displayed via the
1830 splashscreen support or the bmp command.
1832 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1834 If this option is set, 8-bit RLE compressed BMP images
1835 can be displayed via the splashscreen support or the
1838 - Do compresssing for memory range:
1841 If this option is set, it would use zlib deflate method
1842 to compress the specified memory at its best effort.
1844 - Compression support:
1847 Enabled by default to support gzip compressed images.
1851 If this option is set, support for bzip2 compressed
1852 images is included. If not, only uncompressed and gzip
1853 compressed images are supported.
1855 NOTE: the bzip2 algorithm requires a lot of RAM, so
1856 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1861 If this option is set, support for lzma compressed
1864 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1865 requires an amount of dynamic memory that is given by the
1868 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1870 Where lc and lp stand for, respectively, Literal context bits
1871 and Literal pos bits.
1873 This value is upper-bounded by 14MB in the worst case. Anyway,
1874 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1875 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1876 a very small buffer.
1878 Use the lzmainfo tool to determinate the lc and lp values and
1879 then calculate the amount of needed dynamic memory (ensuring
1880 the appropriate CONFIG_SYS_MALLOC_LEN value).
1884 If this option is set, support for LZO compressed images
1890 The address of PHY on MII bus.
1892 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1894 The clock frequency of the MII bus
1898 If this option is set, support for speed/duplex
1899 detection of gigabit PHY is included.
1901 CONFIG_PHY_RESET_DELAY
1903 Some PHY like Intel LXT971A need extra delay after
1904 reset before any MII register access is possible.
1905 For such PHY, set this option to the usec delay
1906 required. (minimum 300usec for LXT971A)
1908 CONFIG_PHY_CMD_DELAY (ppc4xx)
1910 Some PHY like Intel LXT971A need extra delay after
1911 command issued before MII status register can be read
1921 Define a default value for Ethernet address to use
1922 for the respective Ethernet interface, in case this
1923 is not determined automatically.
1928 Define a default value for the IP address to use for
1929 the default Ethernet interface, in case this is not
1930 determined through e.g. bootp.
1931 (Environment variable "ipaddr")
1933 - Server IP address:
1936 Defines a default value for the IP address of a TFTP
1937 server to contact when using the "tftboot" command.
1938 (Environment variable "serverip")
1940 CONFIG_KEEP_SERVERADDR
1942 Keeps the server's MAC address, in the env 'serveraddr'
1943 for passing to bootargs (like Linux's netconsole option)
1945 - Gateway IP address:
1948 Defines a default value for the IP address of the
1949 default router where packets to other networks are
1951 (Environment variable "gatewayip")
1956 Defines a default value for the subnet mask (or
1957 routing prefix) which is used to determine if an IP
1958 address belongs to the local subnet or needs to be
1959 forwarded through a router.
1960 (Environment variable "netmask")
1962 - Multicast TFTP Mode:
1965 Defines whether you want to support multicast TFTP as per
1966 rfc-2090; for example to work with atftp. Lets lots of targets
1967 tftp down the same boot image concurrently. Note: the Ethernet
1968 driver in use must provide a function: mcast() to join/leave a
1971 - BOOTP Recovery Mode:
1972 CONFIG_BOOTP_RANDOM_DELAY
1974 If you have many targets in a network that try to
1975 boot using BOOTP, you may want to avoid that all
1976 systems send out BOOTP requests at precisely the same
1977 moment (which would happen for instance at recovery
1978 from a power failure, when all systems will try to
1979 boot, thus flooding the BOOTP server. Defining
1980 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1981 inserted before sending out BOOTP requests. The
1982 following delays are inserted then:
1984 1st BOOTP request: delay 0 ... 1 sec
1985 2nd BOOTP request: delay 0 ... 2 sec
1986 3rd BOOTP request: delay 0 ... 4 sec
1988 BOOTP requests: delay 0 ... 8 sec
1990 - DHCP Advanced Options:
1991 You can fine tune the DHCP functionality by defining
1992 CONFIG_BOOTP_* symbols:
1994 CONFIG_BOOTP_SUBNETMASK
1995 CONFIG_BOOTP_GATEWAY
1996 CONFIG_BOOTP_HOSTNAME
1997 CONFIG_BOOTP_NISDOMAIN
1998 CONFIG_BOOTP_BOOTPATH
1999 CONFIG_BOOTP_BOOTFILESIZE
2002 CONFIG_BOOTP_SEND_HOSTNAME
2003 CONFIG_BOOTP_NTPSERVER
2004 CONFIG_BOOTP_TIMEOFFSET
2005 CONFIG_BOOTP_VENDOREX
2006 CONFIG_BOOTP_MAY_FAIL
2008 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2009 environment variable, not the BOOTP server.
2011 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2012 after the configured retry count, the call will fail
2013 instead of starting over. This can be used to fail over
2014 to Link-local IP address configuration if the DHCP server
2017 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2018 serverip from a DHCP server, it is possible that more
2019 than one DNS serverip is offered to the client.
2020 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2021 serverip will be stored in the additional environment
2022 variable "dnsip2". The first DNS serverip is always
2023 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2026 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2027 to do a dynamic update of a DNS server. To do this, they
2028 need the hostname of the DHCP requester.
2029 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2030 of the "hostname" environment variable is passed as
2031 option 12 to the DHCP server.
2033 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2035 A 32bit value in microseconds for a delay between
2036 receiving a "DHCP Offer" and sending the "DHCP Request".
2037 This fixes a problem with certain DHCP servers that don't
2038 respond 100% of the time to a "DHCP request". E.g. On an
2039 AT91RM9200 processor running at 180MHz, this delay needed
2040 to be *at least* 15,000 usec before a Windows Server 2003
2041 DHCP server would reply 100% of the time. I recommend at
2042 least 50,000 usec to be safe. The alternative is to hope
2043 that one of the retries will be successful but note that
2044 the DHCP timeout and retry process takes a longer than
2047 - Link-local IP address negotiation:
2048 Negotiate with other link-local clients on the local network
2049 for an address that doesn't require explicit configuration.
2050 This is especially useful if a DHCP server cannot be guaranteed
2051 to exist in all environments that the device must operate.
2053 See doc/README.link-local for more information.
2056 CONFIG_CDP_DEVICE_ID
2058 The device id used in CDP trigger frames.
2060 CONFIG_CDP_DEVICE_ID_PREFIX
2062 A two character string which is prefixed to the MAC address
2067 A printf format string which contains the ascii name of
2068 the port. Normally is set to "eth%d" which sets
2069 eth0 for the first Ethernet, eth1 for the second etc.
2071 CONFIG_CDP_CAPABILITIES
2073 A 32bit integer which indicates the device capabilities;
2074 0x00000010 for a normal host which does not forwards.
2078 An ascii string containing the version of the software.
2082 An ascii string containing the name of the platform.
2086 A 32bit integer sent on the trigger.
2088 CONFIG_CDP_POWER_CONSUMPTION
2090 A 16bit integer containing the power consumption of the
2091 device in .1 of milliwatts.
2093 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2095 A byte containing the id of the VLAN.
2097 - Status LED: CONFIG_STATUS_LED
2099 Several configurations allow to display the current
2100 status using a LED. For instance, the LED will blink
2101 fast while running U-Boot code, stop blinking as
2102 soon as a reply to a BOOTP request was received, and
2103 start blinking slow once the Linux kernel is running
2104 (supported by a status LED driver in the Linux
2105 kernel). Defining CONFIG_STATUS_LED enables this
2111 The status LED can be connected to a GPIO pin.
2112 In such cases, the gpio_led driver can be used as a
2113 status LED backend implementation. Define CONFIG_GPIO_LED
2114 to include the gpio_led driver in the U-Boot binary.
2116 CONFIG_GPIO_LED_INVERTED_TABLE
2117 Some GPIO connected LEDs may have inverted polarity in which
2118 case the GPIO high value corresponds to LED off state and
2119 GPIO low value corresponds to LED on state.
2120 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2121 with a list of GPIO LEDs that have inverted polarity.
2123 - CAN Support: CONFIG_CAN_DRIVER
2125 Defining CONFIG_CAN_DRIVER enables CAN driver support
2126 on those systems that support this (optional)
2127 feature, like the TQM8xxL modules.
2129 - I2C Support: CONFIG_SYS_I2C
2131 This enable the NEW i2c subsystem, and will allow you to use
2132 i2c commands at the u-boot command line (as long as you set
2133 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2134 based realtime clock chips or other i2c devices. See
2135 common/cmd_i2c.c for a description of the command line
2138 ported i2c driver to the new framework:
2139 - drivers/i2c/soft_i2c.c:
2140 - activate first bus with CONFIG_SYS_I2C_SOFT define
2141 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2142 for defining speed and slave address
2143 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2144 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2145 for defining speed and slave address
2146 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2147 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2148 for defining speed and slave address
2149 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2150 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2151 for defining speed and slave address
2153 - drivers/i2c/fsl_i2c.c:
2154 - activate i2c driver with CONFIG_SYS_I2C_FSL
2155 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2156 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2157 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2159 - If your board supports a second fsl i2c bus, define
2160 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2161 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2162 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2165 - drivers/i2c/tegra_i2c.c:
2166 - activate this driver with CONFIG_SYS_I2C_TEGRA
2167 - This driver adds 4 i2c buses with a fix speed from
2168 100000 and the slave addr 0!
2170 - drivers/i2c/ppc4xx_i2c.c
2171 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2172 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2173 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2175 - drivers/i2c/i2c_mxc.c
2176 - activate this driver with CONFIG_SYS_I2C_MXC
2177 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2178 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2179 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2180 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2181 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2182 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2183 If thoses defines are not set, default value is 100000
2184 for speed, and 0 for slave.
2186 - drivers/i2c/rcar_i2c.c:
2187 - activate this driver with CONFIG_SYS_I2C_RCAR
2188 - This driver adds 4 i2c buses
2190 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2191 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2192 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2193 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2194 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2195 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2196 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2197 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2198 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2200 - drivers/i2c/sh_i2c.c:
2201 - activate this driver with CONFIG_SYS_I2C_SH
2202 - This driver adds from 2 to 5 i2c buses
2204 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2205 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2206 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2207 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2208 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2209 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2210 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2211 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2212 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2213 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2214 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2215 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2216 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2218 - drivers/i2c/omap24xx_i2c.c
2219 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2220 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2221 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2222 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2223 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2224 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2225 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2226 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2227 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2228 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2229 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2231 - drivers/i2c/zynq_i2c.c
2232 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2233 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2234 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2236 - drivers/i2c/s3c24x0_i2c.c:
2237 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2238 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2239 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2240 with a fix speed from 100000 and the slave addr 0!
2244 CONFIG_SYS_NUM_I2C_BUSES
2245 Hold the number of i2c busses you want to use. If you
2246 don't use/have i2c muxes on your i2c bus, this
2247 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2250 CONFIG_SYS_I2C_DIRECT_BUS
2251 define this, if you don't use i2c muxes on your hardware.
2252 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2255 CONFIG_SYS_I2C_MAX_HOPS
2256 define how many muxes are maximal consecutively connected
2257 on one i2c bus. If you not use i2c muxes, omit this
2260 CONFIG_SYS_I2C_BUSES
2261 hold a list of busses you want to use, only used if
2262 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2263 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2264 CONFIG_SYS_NUM_I2C_BUSES = 9:
2266 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2267 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2268 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2269 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2270 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2271 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2272 {1, {I2C_NULL_HOP}}, \
2273 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2274 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2278 bus 0 on adapter 0 without a mux
2279 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2280 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2281 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2282 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2283 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2284 bus 6 on adapter 1 without a mux
2285 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2286 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2288 If you do not have i2c muxes on your board, omit this define.
2290 - Legacy I2C Support: CONFIG_HARD_I2C
2292 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2293 provides the following compelling advantages:
2295 - more than one i2c adapter is usable
2296 - approved multibus support
2297 - better i2c mux support
2299 ** Please consider updating your I2C driver now. **
2301 These enable legacy I2C serial bus commands. Defining
2302 CONFIG_HARD_I2C will include the appropriate I2C driver
2303 for the selected CPU.
2305 This will allow you to use i2c commands at the u-boot
2306 command line (as long as you set CONFIG_CMD_I2C in
2307 CONFIG_COMMANDS) and communicate with i2c based realtime
2308 clock chips. See common/cmd_i2c.c for a description of the
2309 command line interface.
2311 CONFIG_HARD_I2C selects a hardware I2C controller.
2313 There are several other quantities that must also be
2314 defined when you define CONFIG_HARD_I2C.
2316 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2317 to be the frequency (in Hz) at which you wish your i2c bus
2318 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2319 the CPU's i2c node address).
2321 Now, the u-boot i2c code for the mpc8xx
2322 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2323 and so its address should therefore be cleared to 0 (See,
2324 eg, MPC823e User's Manual p.16-473). So, set
2325 CONFIG_SYS_I2C_SLAVE to 0.
2327 CONFIG_SYS_I2C_INIT_MPC5XXX
2329 When a board is reset during an i2c bus transfer
2330 chips might think that the current transfer is still
2331 in progress. Reset the slave devices by sending start
2332 commands until the slave device responds.
2334 That's all that's required for CONFIG_HARD_I2C.
2336 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2337 then the following macros need to be defined (examples are
2338 from include/configs/lwmon.h):
2342 (Optional). Any commands necessary to enable the I2C
2343 controller or configure ports.
2345 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2349 (Only for MPC8260 CPU). The I/O port to use (the code
2350 assumes both bits are on the same port). Valid values
2351 are 0..3 for ports A..D.
2355 The code necessary to make the I2C data line active
2356 (driven). If the data line is open collector, this
2359 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2363 The code necessary to make the I2C data line tri-stated
2364 (inactive). If the data line is open collector, this
2367 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2371 Code that returns true if the I2C data line is high,
2374 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2378 If <bit> is true, sets the I2C data line high. If it
2379 is false, it clears it (low).
2381 eg: #define I2C_SDA(bit) \
2382 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2383 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2387 If <bit> is true, sets the I2C clock line high. If it
2388 is false, it clears it (low).
2390 eg: #define I2C_SCL(bit) \
2391 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2392 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2396 This delay is invoked four times per clock cycle so this
2397 controls the rate of data transfer. The data rate thus
2398 is 1 / (I2C_DELAY * 4). Often defined to be something
2401 #define I2C_DELAY udelay(2)
2403 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2405 If your arch supports the generic GPIO framework (asm/gpio.h),
2406 then you may alternatively define the two GPIOs that are to be
2407 used as SCL / SDA. Any of the previous I2C_xxx macros will
2408 have GPIO-based defaults assigned to them as appropriate.
2410 You should define these to the GPIO value as given directly to
2411 the generic GPIO functions.
2413 CONFIG_SYS_I2C_INIT_BOARD
2415 When a board is reset during an i2c bus transfer
2416 chips might think that the current transfer is still
2417 in progress. On some boards it is possible to access
2418 the i2c SCLK line directly, either by using the
2419 processor pin as a GPIO or by having a second pin
2420 connected to the bus. If this option is defined a
2421 custom i2c_init_board() routine in boards/xxx/board.c
2422 is run early in the boot sequence.
2424 CONFIG_SYS_I2C_BOARD_LATE_INIT
2426 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2427 defined a custom i2c_board_late_init() routine in
2428 boards/xxx/board.c is run AFTER the operations in i2c_init()
2429 is completed. This callpoint can be used to unreset i2c bus
2430 using CPU i2c controller register accesses for CPUs whose i2c
2431 controller provide such a method. It is called at the end of
2432 i2c_init() to allow i2c_init operations to setup the i2c bus
2433 controller on the CPU (e.g. setting bus speed & slave address).
2435 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2437 This option enables configuration of bi_iic_fast[] flags
2438 in u-boot bd_info structure based on u-boot environment
2439 variable "i2cfast". (see also i2cfast)
2441 CONFIG_I2C_MULTI_BUS
2443 This option allows the use of multiple I2C buses, each of which
2444 must have a controller. At any point in time, only one bus is
2445 active. To switch to a different bus, use the 'i2c dev' command.
2446 Note that bus numbering is zero-based.
2448 CONFIG_SYS_I2C_NOPROBES
2450 This option specifies a list of I2C devices that will be skipped
2451 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2452 is set, specify a list of bus-device pairs. Otherwise, specify
2453 a 1D array of device addresses
2456 #undef CONFIG_I2C_MULTI_BUS
2457 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2459 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2461 #define CONFIG_I2C_MULTI_BUS
2462 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2464 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2466 CONFIG_SYS_SPD_BUS_NUM
2468 If defined, then this indicates the I2C bus number for DDR SPD.
2469 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2471 CONFIG_SYS_RTC_BUS_NUM
2473 If defined, then this indicates the I2C bus number for the RTC.
2474 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2476 CONFIG_SYS_DTT_BUS_NUM
2478 If defined, then this indicates the I2C bus number for the DTT.
2479 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2481 CONFIG_SYS_I2C_DTT_ADDR:
2483 If defined, specifies the I2C address of the DTT device.
2484 If not defined, then U-Boot uses predefined value for
2485 specified DTT device.
2487 CONFIG_SOFT_I2C_READ_REPEATED_START
2489 defining this will force the i2c_read() function in
2490 the soft_i2c driver to perform an I2C repeated start
2491 between writing the address pointer and reading the
2492 data. If this define is omitted the default behaviour
2493 of doing a stop-start sequence will be used. Most I2C
2494 devices can use either method, but some require one or
2497 - SPI Support: CONFIG_SPI
2499 Enables SPI driver (so far only tested with
2500 SPI EEPROM, also an instance works with Crystal A/D and
2501 D/As on the SACSng board)
2505 Enables the driver for SPI controller on SuperH. Currently
2506 only SH7757 is supported.
2510 Enables extended (16-bit) SPI EEPROM addressing.
2511 (symmetrical to CONFIG_I2C_X)
2515 Enables a software (bit-bang) SPI driver rather than
2516 using hardware support. This is a general purpose
2517 driver that only requires three general I/O port pins
2518 (two outputs, one input) to function. If this is
2519 defined, the board configuration must define several
2520 SPI configuration items (port pins to use, etc). For
2521 an example, see include/configs/sacsng.h.
2525 Enables a hardware SPI driver for general-purpose reads
2526 and writes. As with CONFIG_SOFT_SPI, the board configuration
2527 must define a list of chip-select function pointers.
2528 Currently supported on some MPC8xxx processors. For an
2529 example, see include/configs/mpc8349emds.h.
2533 Enables the driver for the SPI controllers on i.MX and MXC
2534 SoCs. Currently i.MX31/35/51 are supported.
2536 - FPGA Support: CONFIG_FPGA
2538 Enables FPGA subsystem.
2540 CONFIG_FPGA_<vendor>
2542 Enables support for specific chip vendors.
2545 CONFIG_FPGA_<family>
2547 Enables support for FPGA family.
2548 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2552 Specify the number of FPGA devices to support.
2554 CONFIG_SYS_FPGA_PROG_FEEDBACK
2556 Enable printing of hash marks during FPGA configuration.
2558 CONFIG_SYS_FPGA_CHECK_BUSY
2560 Enable checks on FPGA configuration interface busy
2561 status by the configuration function. This option
2562 will require a board or device specific function to
2567 If defined, a function that provides delays in the FPGA
2568 configuration driver.
2570 CONFIG_SYS_FPGA_CHECK_CTRLC
2571 Allow Control-C to interrupt FPGA configuration
2573 CONFIG_SYS_FPGA_CHECK_ERROR
2575 Check for configuration errors during FPGA bitfile
2576 loading. For example, abort during Virtex II
2577 configuration if the INIT_B line goes low (which
2578 indicated a CRC error).
2580 CONFIG_SYS_FPGA_WAIT_INIT
2582 Maximum time to wait for the INIT_B line to deassert
2583 after PROB_B has been deasserted during a Virtex II
2584 FPGA configuration sequence. The default time is 500
2587 CONFIG_SYS_FPGA_WAIT_BUSY
2589 Maximum time to wait for BUSY to deassert during
2590 Virtex II FPGA configuration. The default is 5 ms.
2592 CONFIG_SYS_FPGA_WAIT_CONFIG
2594 Time to wait after FPGA configuration. The default is
2597 - Configuration Management:
2600 If defined, this string will be added to the U-Boot
2601 version information (U_BOOT_VERSION)
2603 - Vendor Parameter Protection:
2605 U-Boot considers the values of the environment
2606 variables "serial#" (Board Serial Number) and
2607 "ethaddr" (Ethernet Address) to be parameters that
2608 are set once by the board vendor / manufacturer, and
2609 protects these variables from casual modification by
2610 the user. Once set, these variables are read-only,
2611 and write or delete attempts are rejected. You can
2612 change this behaviour:
2614 If CONFIG_ENV_OVERWRITE is #defined in your config
2615 file, the write protection for vendor parameters is
2616 completely disabled. Anybody can change or delete
2619 Alternatively, if you #define _both_ CONFIG_ETHADDR
2620 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2621 Ethernet address is installed in the environment,
2622 which can be changed exactly ONCE by the user. [The
2623 serial# is unaffected by this, i. e. it remains
2626 The same can be accomplished in a more flexible way
2627 for any variable by configuring the type of access
2628 to allow for those variables in the ".flags" variable
2629 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2634 Define this variable to enable the reservation of
2635 "protected RAM", i. e. RAM which is not overwritten
2636 by U-Boot. Define CONFIG_PRAM to hold the number of
2637 kB you want to reserve for pRAM. You can overwrite
2638 this default value by defining an environment
2639 variable "pram" to the number of kB you want to
2640 reserve. Note that the board info structure will
2641 still show the full amount of RAM. If pRAM is
2642 reserved, a new environment variable "mem" will
2643 automatically be defined to hold the amount of
2644 remaining RAM in a form that can be passed as boot
2645 argument to Linux, for instance like that:
2647 setenv bootargs ... mem=\${mem}
2650 This way you can tell Linux not to use this memory,
2651 either, which results in a memory region that will
2652 not be affected by reboots.
2654 *WARNING* If your board configuration uses automatic
2655 detection of the RAM size, you must make sure that
2656 this memory test is non-destructive. So far, the
2657 following board configurations are known to be
2660 IVMS8, IVML24, SPD8xx, TQM8xxL,
2661 HERMES, IP860, RPXlite, LWMON,
2664 - Access to physical memory region (> 4GB)
2665 Some basic support is provided for operations on memory not
2666 normally accessible to U-Boot - e.g. some architectures
2667 support access to more than 4GB of memory on 32-bit
2668 machines using physical address extension or similar.
2669 Define CONFIG_PHYSMEM to access this basic support, which
2670 currently only supports clearing the memory.
2675 Define this variable to stop the system in case of a
2676 fatal error, so that you have to reset it manually.
2677 This is probably NOT a good idea for an embedded
2678 system where you want the system to reboot
2679 automatically as fast as possible, but it may be
2680 useful during development since you can try to debug
2681 the conditions that lead to the situation.
2683 CONFIG_NET_RETRY_COUNT
2685 This variable defines the number of retries for
2686 network operations like ARP, RARP, TFTP, or BOOTP
2687 before giving up the operation. If not defined, a
2688 default value of 5 is used.
2692 Timeout waiting for an ARP reply in milliseconds.
2696 Timeout in milliseconds used in NFS protocol.
2697 If you encounter "ERROR: Cannot umount" in nfs command,
2698 try longer timeout such as
2699 #define CONFIG_NFS_TIMEOUT 10000UL
2701 - Command Interpreter:
2702 CONFIG_AUTO_COMPLETE
2704 Enable auto completion of commands using TAB.
2706 Note that this feature has NOT been implemented yet
2707 for the "hush" shell.
2710 CONFIG_SYS_HUSH_PARSER
2712 Define this variable to enable the "hush" shell (from
2713 Busybox) as command line interpreter, thus enabling
2714 powerful command line syntax like
2715 if...then...else...fi conditionals or `&&' and '||'
2716 constructs ("shell scripts").
2718 If undefined, you get the old, much simpler behaviour
2719 with a somewhat smaller memory footprint.
2722 CONFIG_SYS_PROMPT_HUSH_PS2
2724 This defines the secondary prompt string, which is
2725 printed when the command interpreter needs more input
2726 to complete a command. Usually "> ".
2730 In the current implementation, the local variables
2731 space and global environment variables space are
2732 separated. Local variables are those you define by
2733 simply typing `name=value'. To access a local
2734 variable later on, you have write `$name' or
2735 `${name}'; to execute the contents of a variable
2736 directly type `$name' at the command prompt.
2738 Global environment variables are those you use
2739 setenv/printenv to work with. To run a command stored
2740 in such a variable, you need to use the run command,
2741 and you must not use the '$' sign to access them.
2743 To store commands and special characters in a
2744 variable, please use double quotation marks
2745 surrounding the whole text of the variable, instead
2746 of the backslashes before semicolons and special
2749 - Commandline Editing and History:
2750 CONFIG_CMDLINE_EDITING
2752 Enable editing and History functions for interactive
2753 commandline input operations
2755 - Default Environment:
2756 CONFIG_EXTRA_ENV_SETTINGS
2758 Define this to contain any number of null terminated
2759 strings (variable = value pairs) that will be part of
2760 the default environment compiled into the boot image.
2762 For example, place something like this in your
2763 board's config file:
2765 #define CONFIG_EXTRA_ENV_SETTINGS \
2769 Warning: This method is based on knowledge about the
2770 internal format how the environment is stored by the
2771 U-Boot code. This is NOT an official, exported
2772 interface! Although it is unlikely that this format
2773 will change soon, there is no guarantee either.
2774 You better know what you are doing here.
2776 Note: overly (ab)use of the default environment is
2777 discouraged. Make sure to check other ways to preset
2778 the environment like the "source" command or the
2781 CONFIG_ENV_VARS_UBOOT_CONFIG
2783 Define this in order to add variables describing the
2784 U-Boot build configuration to the default environment.
2785 These will be named arch, cpu, board, vendor, and soc.
2787 Enabling this option will cause the following to be defined:
2795 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2797 Define this in order to add variables describing certain
2798 run-time determined information about the hardware to the
2799 environment. These will be named board_name, board_rev.
2801 CONFIG_DELAY_ENVIRONMENT
2803 Normally the environment is loaded when the board is
2804 intialised so that it is available to U-Boot. This inhibits
2805 that so that the environment is not available until
2806 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2807 this is instead controlled by the value of
2808 /config/load-environment.
2810 - DataFlash Support:
2811 CONFIG_HAS_DATAFLASH
2813 Defining this option enables DataFlash features and
2814 allows to read/write in Dataflash via the standard
2817 - Serial Flash support
2820 Defining this option enables SPI flash commands
2821 'sf probe/read/write/erase/update'.
2823 Usage requires an initial 'probe' to define the serial
2824 flash parameters, followed by read/write/erase/update
2827 The following defaults may be provided by the platform
2828 to handle the common case when only a single serial
2829 flash is present on the system.
2831 CONFIG_SF_DEFAULT_BUS Bus identifier
2832 CONFIG_SF_DEFAULT_CS Chip-select
2833 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2834 CONFIG_SF_DEFAULT_SPEED in Hz
2838 Define this option to include a destructive SPI flash
2841 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2843 Define this option to use the Bank addr/Extended addr
2844 support on SPI flashes which has size > 16Mbytes.
2846 CONFIG_SF_DUAL_FLASH Dual flash memories
2848 Define this option to use dual flash support where two flash
2849 memories can be connected with a given cs line.
2850 currently Xilinx Zynq qspi support these type of connections.
2852 - SystemACE Support:
2855 Adding this option adds support for Xilinx SystemACE
2856 chips attached via some sort of local bus. The address
2857 of the chip must also be defined in the
2858 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2860 #define CONFIG_SYSTEMACE
2861 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2863 When SystemACE support is added, the "ace" device type
2864 becomes available to the fat commands, i.e. fatls.
2866 - TFTP Fixed UDP Port:
2869 If this is defined, the environment variable tftpsrcp
2870 is used to supply the TFTP UDP source port value.
2871 If tftpsrcp isn't defined, the normal pseudo-random port
2872 number generator is used.
2874 Also, the environment variable tftpdstp is used to supply
2875 the TFTP UDP destination port value. If tftpdstp isn't
2876 defined, the normal port 69 is used.
2878 The purpose for tftpsrcp is to allow a TFTP server to
2879 blindly start the TFTP transfer using the pre-configured
2880 target IP address and UDP port. This has the effect of
2881 "punching through" the (Windows XP) firewall, allowing
2882 the remainder of the TFTP transfer to proceed normally.
2883 A better solution is to properly configure the firewall,
2884 but sometimes that is not allowed.
2889 This enables a generic 'hash' command which can produce
2890 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2894 Enable the hash verify command (hash -v). This adds to code
2897 CONFIG_SHA1 - support SHA1 hashing
2898 CONFIG_SHA256 - support SHA256 hashing
2900 Note: There is also a sha1sum command, which should perhaps
2901 be deprecated in favour of 'hash sha1'.
2903 - Freescale i.MX specific commands:
2904 CONFIG_CMD_HDMIDETECT
2905 This enables 'hdmidet' command which returns true if an
2906 HDMI monitor is detected. This command is i.MX 6 specific.
2909 This enables the 'bmode' (bootmode) command for forcing
2910 a boot from specific media.
2912 This is useful for forcing the ROM's usb downloader to
2913 activate upon a watchdog reset which is nice when iterating
2914 on U-Boot. Using the reset button or running bmode normal
2915 will set it back to normal. This command currently
2916 supports i.MX53 and i.MX6.
2921 This enables the RSA algorithm used for FIT image verification
2922 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2924 The signing part is build into mkimage regardless of this
2927 - bootcount support:
2928 CONFIG_BOOTCOUNT_LIMIT
2930 This enables the bootcounter support, see:
2931 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2934 enable special bootcounter support on at91sam9xe based boards.
2936 enable special bootcounter support on blackfin based boards.
2938 enable special bootcounter support on da850 based boards.
2939 CONFIG_BOOTCOUNT_RAM
2940 enable support for the bootcounter in RAM
2941 CONFIG_BOOTCOUNT_I2C
2942 enable support for the bootcounter on an i2c (like RTC) device.
2943 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2944 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2946 CONFIG_BOOTCOUNT_ALEN = address len
2948 - Show boot progress:
2949 CONFIG_SHOW_BOOT_PROGRESS
2951 Defining this option allows to add some board-
2952 specific code (calling a user-provided function
2953 "show_boot_progress(int)") that enables you to show
2954 the system's boot progress on some display (for
2955 example, some LED's) on your board. At the moment,
2956 the following checkpoints are implemented:
2958 - Detailed boot stage timing
2960 Define this option to get detailed timing of each stage
2961 of the boot process.
2963 CONFIG_BOOTSTAGE_USER_COUNT
2964 This is the number of available user bootstage records.
2965 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2966 a new ID will be allocated from this stash. If you exceed
2967 the limit, recording will stop.
2969 CONFIG_BOOTSTAGE_REPORT
2970 Define this to print a report before boot, similar to this:
2972 Timer summary in microseconds:
2975 3,575,678 3,575,678 board_init_f start
2976 3,575,695 17 arch_cpu_init A9
2977 3,575,777 82 arch_cpu_init done
2978 3,659,598 83,821 board_init_r start
2979 3,910,375 250,777 main_loop
2980 29,916,167 26,005,792 bootm_start
2981 30,361,327 445,160 start_kernel
2983 CONFIG_CMD_BOOTSTAGE
2984 Add a 'bootstage' command which supports printing a report
2985 and un/stashing of bootstage data.
2987 CONFIG_BOOTSTAGE_FDT
2988 Stash the bootstage information in the FDT. A root 'bootstage'
2989 node is created with each bootstage id as a child. Each child
2990 has a 'name' property and either 'mark' containing the
2991 mark time in microsecond, or 'accum' containing the
2992 accumulated time for that bootstage id in microseconds.
2997 name = "board_init_f";
3006 Code in the Linux kernel can find this in /proc/devicetree.
3008 Legacy uImage format:
3011 1 common/cmd_bootm.c before attempting to boot an image
3012 -1 common/cmd_bootm.c Image header has bad magic number
3013 2 common/cmd_bootm.c Image header has correct magic number
3014 -2 common/cmd_bootm.c Image header has bad checksum
3015 3 common/cmd_bootm.c Image header has correct checksum
3016 -3 common/cmd_bootm.c Image data has bad checksum
3017 4 common/cmd_bootm.c Image data has correct checksum
3018 -4 common/cmd_bootm.c Image is for unsupported architecture
3019 5 common/cmd_bootm.c Architecture check OK
3020 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3021 6 common/cmd_bootm.c Image Type check OK
3022 -6 common/cmd_bootm.c gunzip uncompression error
3023 -7 common/cmd_bootm.c Unimplemented compression type
3024 7 common/cmd_bootm.c Uncompression OK
3025 8 common/cmd_bootm.c No uncompress/copy overwrite error
3026 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3028 9 common/image.c Start initial ramdisk verification
3029 -10 common/image.c Ramdisk header has bad magic number
3030 -11 common/image.c Ramdisk header has bad checksum
3031 10 common/image.c Ramdisk header is OK
3032 -12 common/image.c Ramdisk data has bad checksum
3033 11 common/image.c Ramdisk data has correct checksum
3034 12 common/image.c Ramdisk verification complete, start loading
3035 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3036 13 common/image.c Start multifile image verification
3037 14 common/image.c No initial ramdisk, no multifile, continue.
3039 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3041 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3042 -31 post/post.c POST test failed, detected by post_output_backlog()
3043 -32 post/post.c POST test failed, detected by post_run_single()
3045 34 common/cmd_doc.c before loading a Image from a DOC device
3046 -35 common/cmd_doc.c Bad usage of "doc" command
3047 35 common/cmd_doc.c correct usage of "doc" command
3048 -36 common/cmd_doc.c No boot device
3049 36 common/cmd_doc.c correct boot device
3050 -37 common/cmd_doc.c Unknown Chip ID on boot device
3051 37 common/cmd_doc.c correct chip ID found, device available
3052 -38 common/cmd_doc.c Read Error on boot device
3053 38 common/cmd_doc.c reading Image header from DOC device OK
3054 -39 common/cmd_doc.c Image header has bad magic number
3055 39 common/cmd_doc.c Image header has correct magic number
3056 -40 common/cmd_doc.c Error reading Image from DOC device
3057 40 common/cmd_doc.c Image header has correct magic number
3058 41 common/cmd_ide.c before loading a Image from a IDE device
3059 -42 common/cmd_ide.c Bad usage of "ide" command
3060 42 common/cmd_ide.c correct usage of "ide" command
3061 -43 common/cmd_ide.c No boot device
3062 43 common/cmd_ide.c boot device found
3063 -44 common/cmd_ide.c Device not available
3064 44 common/cmd_ide.c Device available
3065 -45 common/cmd_ide.c wrong partition selected
3066 45 common/cmd_ide.c partition selected
3067 -46 common/cmd_ide.c Unknown partition table
3068 46 common/cmd_ide.c valid partition table found
3069 -47 common/cmd_ide.c Invalid partition type
3070 47 common/cmd_ide.c correct partition type
3071 -48 common/cmd_ide.c Error reading Image Header on boot device
3072 48 common/cmd_ide.c reading Image Header from IDE device OK
3073 -49 common/cmd_ide.c Image header has bad magic number
3074 49 common/cmd_ide.c Image header has correct magic number
3075 -50 common/cmd_ide.c Image header has bad checksum
3076 50 common/cmd_ide.c Image header has correct checksum
3077 -51 common/cmd_ide.c Error reading Image from IDE device
3078 51 common/cmd_ide.c reading Image from IDE device OK
3079 52 common/cmd_nand.c before loading a Image from a NAND device
3080 -53 common/cmd_nand.c Bad usage of "nand" command
3081 53 common/cmd_nand.c correct usage of "nand" command
3082 -54 common/cmd_nand.c No boot device
3083 54 common/cmd_nand.c boot device found
3084 -55 common/cmd_nand.c Unknown Chip ID on boot device
3085 55 common/cmd_nand.c correct chip ID found, device available
3086 -56 common/cmd_nand.c Error reading Image Header on boot device
3087 56 common/cmd_nand.c reading Image Header from NAND device OK
3088 -57 common/cmd_nand.c Image header has bad magic number
3089 57 common/cmd_nand.c Image header has correct magic number
3090 -58 common/cmd_nand.c Error reading Image from NAND device
3091 58 common/cmd_nand.c reading Image from NAND device OK
3093 -60 common/env_common.c Environment has a bad CRC, using default
3095 64 net/eth.c starting with Ethernet configuration.
3096 -64 net/eth.c no Ethernet found.
3097 65 net/eth.c Ethernet found.
3099 -80 common/cmd_net.c usage wrong
3100 80 common/cmd_net.c before calling NetLoop()
3101 -81 common/cmd_net.c some error in NetLoop() occurred
3102 81 common/cmd_net.c NetLoop() back without error
3103 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3104 82 common/cmd_net.c trying automatic boot
3105 83 common/cmd_net.c running "source" command
3106 -83 common/cmd_net.c some error in automatic boot or "source" command
3107 84 common/cmd_net.c end without errors
3112 100 common/cmd_bootm.c Kernel FIT Image has correct format
3113 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3114 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3115 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3116 102 common/cmd_bootm.c Kernel unit name specified
3117 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3118 103 common/cmd_bootm.c Found configuration node
3119 104 common/cmd_bootm.c Got kernel subimage node offset
3120 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3121 105 common/cmd_bootm.c Kernel subimage hash verification OK
3122 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3123 106 common/cmd_bootm.c Architecture check OK
3124 -106 common/cmd_bootm.c Kernel subimage has wrong type
3125 107 common/cmd_bootm.c Kernel subimage type OK
3126 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3127 108 common/cmd_bootm.c Got kernel subimage data/size
3128 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3129 -109 common/cmd_bootm.c Can't get kernel subimage type
3130 -110 common/cmd_bootm.c Can't get kernel subimage comp
3131 -111 common/cmd_bootm.c Can't get kernel subimage os
3132 -112 common/cmd_bootm.c Can't get kernel subimage load address
3133 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3135 120 common/image.c Start initial ramdisk verification
3136 -120 common/image.c Ramdisk FIT image has incorrect format
3137 121 common/image.c Ramdisk FIT image has correct format
3138 122 common/image.c No ramdisk subimage unit name, using configuration
3139 -122 common/image.c Can't get configuration for ramdisk subimage
3140 123 common/image.c Ramdisk unit name specified
3141 -124 common/image.c Can't get ramdisk subimage node offset
3142 125 common/image.c Got ramdisk subimage node offset
3143 -125 common/image.c Ramdisk subimage hash verification failed
3144 126 common/image.c Ramdisk subimage hash verification OK
3145 -126 common/image.c Ramdisk subimage for unsupported architecture
3146 127 common/image.c Architecture check OK
3147 -127 common/image.c Can't get ramdisk subimage data/size
3148 128 common/image.c Got ramdisk subimage data/size
3149 129 common/image.c Can't get ramdisk load address
3150 -129 common/image.c Got ramdisk load address
3152 -130 common/cmd_doc.c Incorrect FIT image format
3153 131 common/cmd_doc.c FIT image format OK
3155 -140 common/cmd_ide.c Incorrect FIT image format
3156 141 common/cmd_ide.c FIT image format OK
3158 -150 common/cmd_nand.c Incorrect FIT image format
3159 151 common/cmd_nand.c FIT image format OK
3161 - FIT image support:
3163 Enable support for the FIT uImage format.
3165 CONFIG_FIT_BEST_MATCH
3166 When no configuration is explicitly selected, default to the
3167 one whose fdt's compatibility field best matches that of
3168 U-Boot itself. A match is considered "best" if it matches the
3169 most specific compatibility entry of U-Boot's fdt's root node.
3170 The order of entries in the configuration's fdt is ignored.
3172 CONFIG_FIT_SIGNATURE
3173 This option enables signature verification of FIT uImages,
3174 using a hash signed and verified using RSA. See
3175 doc/uImage.FIT/signature.txt for more details.
3177 - Standalone program support:
3178 CONFIG_STANDALONE_LOAD_ADDR
3180 This option defines a board specific value for the
3181 address where standalone program gets loaded, thus
3182 overwriting the architecture dependent default
3185 - Frame Buffer Address:
3188 Define CONFIG_FB_ADDR if you want to use specific
3189 address for frame buffer. This is typically the case
3190 when using a graphics controller has separate video
3191 memory. U-Boot will then place the frame buffer at
3192 the given address instead of dynamically reserving it
3193 in system RAM by calling lcd_setmem(), which grabs
3194 the memory for the frame buffer depending on the
3195 configured panel size.
3197 Please see board_init_f function.
3199 - Automatic software updates via TFTP server
3201 CONFIG_UPDATE_TFTP_CNT_MAX
3202 CONFIG_UPDATE_TFTP_MSEC_MAX
3204 These options enable and control the auto-update feature;
3205 for a more detailed description refer to doc/README.update.
3207 - MTD Support (mtdparts command, UBI support)
3210 Adds the MTD device infrastructure from the Linux kernel.
3211 Needed for mtdparts command support.
3213 CONFIG_MTD_PARTITIONS
3215 Adds the MTD partitioning infrastructure from the Linux
3216 kernel. Needed for UBI support.
3221 Adds commands for interacting with MTD partitions formatted
3222 with the UBI flash translation layer
3224 Requires also defining CONFIG_RBTREE
3226 CONFIG_UBI_SILENCE_MSG
3228 Make the verbose messages from UBI stop printing. This leaves
3229 warnings and errors enabled.
3234 Adds commands for interacting with UBI volumes formatted as
3235 UBIFS. UBIFS is read-only in u-boot.
3237 Requires UBI support as well as CONFIG_LZO
3239 CONFIG_UBIFS_SILENCE_MSG
3241 Make the verbose messages from UBIFS stop printing. This leaves
3242 warnings and errors enabled.
3246 Enable building of SPL globally.
3249 LDSCRIPT for linking the SPL binary.
3251 CONFIG_SPL_MAX_FOOTPRINT
3252 Maximum size in memory allocated to the SPL, BSS included.
3253 When defined, the linker checks that the actual memory
3254 used by SPL from _start to __bss_end does not exceed it.
3255 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3256 must not be both defined at the same time.
3259 Maximum size of the SPL image (text, data, rodata, and
3260 linker lists sections), BSS excluded.
3261 When defined, the linker checks that the actual size does
3264 CONFIG_SPL_TEXT_BASE
3265 TEXT_BASE for linking the SPL binary.
3267 CONFIG_SPL_RELOC_TEXT_BASE
3268 Address to relocate to. If unspecified, this is equal to
3269 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3271 CONFIG_SPL_BSS_START_ADDR
3272 Link address for the BSS within the SPL binary.
3274 CONFIG_SPL_BSS_MAX_SIZE
3275 Maximum size in memory allocated to the SPL BSS.
3276 When defined, the linker checks that the actual memory used
3277 by SPL from __bss_start to __bss_end does not exceed it.
3278 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3279 must not be both defined at the same time.
3282 Adress of the start of the stack SPL will use
3284 CONFIG_SPL_RELOC_STACK
3285 Adress of the start of the stack SPL will use after
3286 relocation. If unspecified, this is equal to
3289 CONFIG_SYS_SPL_MALLOC_START
3290 Starting address of the malloc pool used in SPL.
3292 CONFIG_SYS_SPL_MALLOC_SIZE
3293 The size of the malloc pool used in SPL.
3295 CONFIG_SPL_FRAMEWORK
3296 Enable the SPL framework under common/. This framework
3297 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3298 NAND loading of the Linux Kernel.
3300 CONFIG_SPL_DISPLAY_PRINT
3301 For ARM, enable an optional function to print more information
3302 about the running system.
3304 CONFIG_SPL_INIT_MINIMAL
3305 Arch init code should be built for a very small image
3307 CONFIG_SPL_LIBCOMMON_SUPPORT
3308 Support for common/libcommon.o in SPL binary
3310 CONFIG_SPL_LIBDISK_SUPPORT
3311 Support for disk/libdisk.o in SPL binary
3313 CONFIG_SPL_I2C_SUPPORT
3314 Support for drivers/i2c/libi2c.o in SPL binary
3316 CONFIG_SPL_GPIO_SUPPORT
3317 Support for drivers/gpio/libgpio.o in SPL binary
3319 CONFIG_SPL_MMC_SUPPORT
3320 Support for drivers/mmc/libmmc.o in SPL binary
3322 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3323 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3324 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3325 Address, size and partition on the MMC to load U-Boot from
3326 when the MMC is being used in raw mode.
3328 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3329 Sector to load kernel uImage from when MMC is being
3330 used in raw mode (for Falcon mode)
3332 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3333 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3334 Sector and number of sectors to load kernel argument
3335 parameters from when MMC is being used in raw mode
3338 CONFIG_SPL_FAT_SUPPORT
3339 Support for fs/fat/libfat.o in SPL binary
3341 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3342 Filename to read to load U-Boot when reading from FAT
3344 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3345 Filename to read to load kernel uImage when reading
3346 from FAT (for Falcon mode)
3348 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3349 Filename to read to load kernel argument parameters
3350 when reading from FAT (for Falcon mode)
3352 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3353 Set this for NAND SPL on PPC mpc83xx targets, so that
3354 start.S waits for the rest of the SPL to load before
3355 continuing (the hardware starts execution after just
3356 loading the first page rather than the full 4K).
3358 CONFIG_SPL_SKIP_RELOCATE
3359 Avoid SPL relocation
3361 CONFIG_SPL_NAND_BASE
3362 Include nand_base.c in the SPL. Requires
3363 CONFIG_SPL_NAND_DRIVERS.
3365 CONFIG_SPL_NAND_DRIVERS
3366 SPL uses normal NAND drivers, not minimal drivers.
3369 Include standard software ECC in the SPL
3371 CONFIG_SPL_NAND_SIMPLE
3372 Support for NAND boot using simple NAND drivers that
3373 expose the cmd_ctrl() interface.
3375 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3376 Set for the SPL on PPC mpc8xxx targets, support for
3377 drivers/ddr/fsl/libddr.o in SPL binary.
3379 CONFIG_SPL_COMMON_INIT_DDR
3380 Set for common ddr init with serial presence detect in
3383 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3384 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3385 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3386 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3387 CONFIG_SYS_NAND_ECCBYTES
3388 Defines the size and behavior of the NAND that SPL uses
3391 CONFIG_SPL_NAND_BOOT
3392 Add support NAND boot
3394 CONFIG_SYS_NAND_U_BOOT_OFFS
3395 Location in NAND to read U-Boot from
3397 CONFIG_SYS_NAND_U_BOOT_DST
3398 Location in memory to load U-Boot to
3400 CONFIG_SYS_NAND_U_BOOT_SIZE
3401 Size of image to load
3403 CONFIG_SYS_NAND_U_BOOT_START
3404 Entry point in loaded image to jump to
3406 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3407 Define this if you need to first read the OOB and then the
3408 data. This is used for example on davinci plattforms.
3410 CONFIG_SPL_OMAP3_ID_NAND
3411 Support for an OMAP3-specific set of functions to return the
3412 ID and MFR of the first attached NAND chip, if present.
3414 CONFIG_SPL_SERIAL_SUPPORT
3415 Support for drivers/serial/libserial.o in SPL binary
3417 CONFIG_SPL_SPI_FLASH_SUPPORT
3418 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3420 CONFIG_SPL_SPI_SUPPORT
3421 Support for drivers/spi/libspi.o in SPL binary
3423 CONFIG_SPL_RAM_DEVICE
3424 Support for running image already present in ram, in SPL binary
3426 CONFIG_SPL_LIBGENERIC_SUPPORT
3427 Support for lib/libgeneric.o in SPL binary
3429 CONFIG_SPL_ENV_SUPPORT
3430 Support for the environment operating in SPL binary
3432 CONFIG_SPL_NET_SUPPORT
3433 Support for the net/libnet.o in SPL binary.
3434 It conflicts with SPL env from storage medium specified by
3435 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3438 Image offset to which the SPL should be padded before appending
3439 the SPL payload. By default, this is defined as
3440 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3441 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3442 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3445 Final target image containing SPL and payload. Some SPLs
3446 use an arch-specific makefile fragment instead, for
3447 example if more than one image needs to be produced.
3449 CONFIG_FIT_SPL_PRINT
3450 Printing information about a FIT image adds quite a bit of
3451 code to SPL. So this is normally disabled in SPL. Use this
3452 option to re-enable it. This will affect the output of the
3453 bootm command when booting a FIT image.
3457 Enable building of TPL globally.
3460 Image offset to which the TPL should be padded before appending
3461 the TPL payload. By default, this is defined as
3462 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3463 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3464 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3469 [so far only for SMDK2400 boards]
3471 - Modem support enable:
3472 CONFIG_MODEM_SUPPORT
3474 - RTS/CTS Flow control enable:
3477 - Modem debug support:
3478 CONFIG_MODEM_SUPPORT_DEBUG
3480 Enables debugging stuff (char screen[1024], dbg())
3481 for modem support. Useful only with BDI2000.
3483 - Interrupt support (PPC):
3485 There are common interrupt_init() and timer_interrupt()
3486 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3487 for CPU specific initialization. interrupt_init_cpu()
3488 should set decrementer_count to appropriate value. If
3489 CPU resets decrementer automatically after interrupt
3490 (ppc4xx) it should set decrementer_count to zero.
3491 timer_interrupt() calls timer_interrupt_cpu() for CPU
3492 specific handling. If board has watchdog / status_led
3493 / other_activity_monitor it works automatically from
3494 general timer_interrupt().
3498 In the target system modem support is enabled when a
3499 specific key (key combination) is pressed during
3500 power-on. Otherwise U-Boot will boot normally
3501 (autoboot). The key_pressed() function is called from
3502 board_init(). Currently key_pressed() is a dummy
3503 function, returning 1 and thus enabling modem
3506 If there are no modem init strings in the
3507 environment, U-Boot proceed to autoboot; the
3508 previous output (banner, info printfs) will be
3511 See also: doc/README.Modem
3513 Board initialization settings:
3514 ------------------------------
3516 During Initialization u-boot calls a number of board specific functions
3517 to allow the preparation of board specific prerequisites, e.g. pin setup
3518 before drivers are initialized. To enable these callbacks the
3519 following configuration macros have to be defined. Currently this is
3520 architecture specific, so please check arch/your_architecture/lib/board.c
3521 typically in board_init_f() and board_init_r().
3523 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3524 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3525 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3526 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3528 Configuration Settings:
3529 -----------------------
3531 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3532 Optionally it can be defined to support 64-bit memory commands.
3534 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3535 undefine this when you're short of memory.
3537 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3538 width of the commands listed in the 'help' command output.
3540 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3541 prompt for user input.
3543 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3545 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3547 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3549 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3550 the application (usually a Linux kernel) when it is
3553 - CONFIG_SYS_BAUDRATE_TABLE:
3554 List of legal baudrate settings for this board.
3556 - CONFIG_SYS_CONSOLE_INFO_QUIET
3557 Suppress display of console information at boot.
3559 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3560 If the board specific function
3561 extern int overwrite_console (void);
3562 returns 1, the stdin, stderr and stdout are switched to the
3563 serial port, else the settings in the environment are used.
3565 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3566 Enable the call to overwrite_console().
3568 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3569 Enable overwrite of previous console environment settings.
3571 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3572 Begin and End addresses of the area used by the
3575 - CONFIG_SYS_ALT_MEMTEST:
3576 Enable an alternate, more extensive memory test.
3578 - CONFIG_SYS_MEMTEST_SCRATCH:
3579 Scratch address used by the alternate memory test
3580 You only need to set this if address zero isn't writeable
3582 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3583 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3584 this specified memory area will get subtracted from the top
3585 (end) of RAM and won't get "touched" at all by U-Boot. By
3586 fixing up gd->ram_size the Linux kernel should gets passed
3587 the now "corrected" memory size and won't touch it either.
3588 This should work for arch/ppc and arch/powerpc. Only Linux
3589 board ports in arch/powerpc with bootwrapper support that
3590 recalculate the memory size from the SDRAM controller setup
3591 will have to get fixed in Linux additionally.
3593 This option can be used as a workaround for the 440EPx/GRx
3594 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3597 WARNING: Please make sure that this value is a multiple of
3598 the Linux page size (normally 4k). If this is not the case,
3599 then the end address of the Linux memory will be located at a
3600 non page size aligned address and this could cause major
3603 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3604 Enable temporary baudrate change while serial download
3606 - CONFIG_SYS_SDRAM_BASE:
3607 Physical start address of SDRAM. _Must_ be 0 here.
3609 - CONFIG_SYS_MBIO_BASE:
3610 Physical start address of Motherboard I/O (if using a
3613 - CONFIG_SYS_FLASH_BASE:
3614 Physical start address of Flash memory.
3616 - CONFIG_SYS_MONITOR_BASE:
3617 Physical start address of boot monitor code (set by
3618 make config files to be same as the text base address
3619 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3620 CONFIG_SYS_FLASH_BASE when booting from flash.
3622 - CONFIG_SYS_MONITOR_LEN:
3623 Size of memory reserved for monitor code, used to
3624 determine _at_compile_time_ (!) if the environment is
3625 embedded within the U-Boot image, or in a separate
3628 - CONFIG_SYS_MALLOC_LEN:
3629 Size of DRAM reserved for malloc() use.
3631 - CONFIG_SYS_BOOTM_LEN:
3632 Normally compressed uImages are limited to an
3633 uncompressed size of 8 MBytes. If this is not enough,
3634 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3635 to adjust this setting to your needs.
3637 - CONFIG_SYS_BOOTMAPSZ:
3638 Maximum size of memory mapped by the startup code of
3639 the Linux kernel; all data that must be processed by
3640 the Linux kernel (bd_info, boot arguments, FDT blob if
3641 used) must be put below this limit, unless "bootm_low"
3642 environment variable is defined and non-zero. In such case
3643 all data for the Linux kernel must be between "bootm_low"
3644 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3645 variable "bootm_mapsize" will override the value of
3646 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3647 then the value in "bootm_size" will be used instead.
3649 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3650 Enable initrd_high functionality. If defined then the
3651 initrd_high feature is enabled and the bootm ramdisk subcommand
3654 - CONFIG_SYS_BOOT_GET_CMDLINE:
3655 Enables allocating and saving kernel cmdline in space between
3656 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3658 - CONFIG_SYS_BOOT_GET_KBD:
3659 Enables allocating and saving a kernel copy of the bd_info in
3660 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3662 - CONFIG_SYS_MAX_FLASH_BANKS:
3663 Max number of Flash memory banks
3665 - CONFIG_SYS_MAX_FLASH_SECT:
3666 Max number of sectors on a Flash chip
3668 - CONFIG_SYS_FLASH_ERASE_TOUT:
3669 Timeout for Flash erase operations (in ms)
3671 - CONFIG_SYS_FLASH_WRITE_TOUT:
3672 Timeout for Flash write operations (in ms)
3674 - CONFIG_SYS_FLASH_LOCK_TOUT
3675 Timeout for Flash set sector lock bit operation (in ms)
3677 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3678 Timeout for Flash clear lock bits operation (in ms)
3680 - CONFIG_SYS_FLASH_PROTECTION
3681 If defined, hardware flash sectors protection is used
3682 instead of U-Boot software protection.
3684 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3686 Enable TFTP transfers directly to flash memory;
3687 without this option such a download has to be
3688 performed in two steps: (1) download to RAM, and (2)
3689 copy from RAM to flash.
3691 The two-step approach is usually more reliable, since
3692 you can check if the download worked before you erase
3693 the flash, but in some situations (when system RAM is
3694 too limited to allow for a temporary copy of the
3695 downloaded image) this option may be very useful.
3697 - CONFIG_SYS_FLASH_CFI:
3698 Define if the flash driver uses extra elements in the
3699 common flash structure for storing flash geometry.
3701 - CONFIG_FLASH_CFI_DRIVER
3702 This option also enables the building of the cfi_flash driver
3703 in the drivers directory
3705 - CONFIG_FLASH_CFI_MTD
3706 This option enables the building of the cfi_mtd driver
3707 in the drivers directory. The driver exports CFI flash
3710 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3711 Use buffered writes to flash.
3713 - CONFIG_FLASH_SPANSION_S29WS_N
3714 s29ws-n MirrorBit flash has non-standard addresses for buffered
3717 - CONFIG_SYS_FLASH_QUIET_TEST
3718 If this option is defined, the common CFI flash doesn't
3719 print it's warning upon not recognized FLASH banks. This
3720 is useful, if some of the configured banks are only
3721 optionally available.
3723 - CONFIG_FLASH_SHOW_PROGRESS
3724 If defined (must be an integer), print out countdown
3725 digits and dots. Recommended value: 45 (9..1) for 80
3726 column displays, 15 (3..1) for 40 column displays.
3728 - CONFIG_FLASH_VERIFY
3729 If defined, the content of the flash (destination) is compared
3730 against the source after the write operation. An error message
3731 will be printed when the contents are not identical.
3732 Please note that this option is useless in nearly all cases,
3733 since such flash programming errors usually are detected earlier
3734 while unprotecting/erasing/programming. Please only enable
3735 this option if you really know what you are doing.
3737 - CONFIG_SYS_RX_ETH_BUFFER:
3738 Defines the number of Ethernet receive buffers. On some
3739 Ethernet controllers it is recommended to set this value
3740 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3741 buffers can be full shortly after enabling the interface
3742 on high Ethernet traffic.
3743 Defaults to 4 if not defined.
3745 - CONFIG_ENV_MAX_ENTRIES
3747 Maximum number of entries in the hash table that is used
3748 internally to store the environment settings. The default
3749 setting is supposed to be generous and should work in most
3750 cases. This setting can be used to tune behaviour; see
3751 lib/hashtable.c for details.
3753 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3754 - CONFIG_ENV_FLAGS_LIST_STATIC
3755 Enable validation of the values given to environment variables when
3756 calling env set. Variables can be restricted to only decimal,
3757 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3758 the variables can also be restricted to IP address or MAC address.
3760 The format of the list is:
3761 type_attribute = [s|d|x|b|i|m]
3762 access_atribute = [a|r|o|c]
3763 attributes = type_attribute[access_atribute]
3764 entry = variable_name[:attributes]
3767 The type attributes are:
3768 s - String (default)
3771 b - Boolean ([1yYtT|0nNfF])
3775 The access attributes are:
3781 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3782 Define this to a list (string) to define the ".flags"
3783 envirnoment variable in the default or embedded environment.
3785 - CONFIG_ENV_FLAGS_LIST_STATIC
3786 Define this to a list (string) to define validation that
3787 should be done if an entry is not found in the ".flags"
3788 environment variable. To override a setting in the static
3789 list, simply add an entry for the same variable name to the
3792 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3793 If defined, don't allow the -f switch to env set override variable
3796 - CONFIG_SYS_GENERIC_BOARD
3797 This selects the architecture-generic board system instead of the
3798 architecture-specific board files. It is intended to move boards
3799 to this new framework over time. Defining this will disable the
3800 arch/foo/lib/board.c file and use common/board_f.c and
3801 common/board_r.c instead. To use this option your architecture
3802 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3803 its config.mk file). If you find problems enabling this option on
3804 your board please report the problem and send patches!
3806 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3807 This is set by OMAP boards for the max time that reset should
3808 be asserted. See doc/README.omap-reset-time for details on how
3809 the value can be calulated on a given board.
3811 The following definitions that deal with the placement and management
3812 of environment data (variable area); in general, we support the
3813 following configurations:
3815 - CONFIG_BUILD_ENVCRC:
3817 Builds up envcrc with the target environment so that external utils
3818 may easily extract it and embed it in final U-Boot images.
3820 - CONFIG_ENV_IS_IN_FLASH:
3822 Define this if the environment is in flash memory.
3824 a) The environment occupies one whole flash sector, which is
3825 "embedded" in the text segment with the U-Boot code. This
3826 happens usually with "bottom boot sector" or "top boot
3827 sector" type flash chips, which have several smaller
3828 sectors at the start or the end. For instance, such a
3829 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3830 such a case you would place the environment in one of the
3831 4 kB sectors - with U-Boot code before and after it. With
3832 "top boot sector" type flash chips, you would put the
3833 environment in one of the last sectors, leaving a gap
3834 between U-Boot and the environment.
3836 - CONFIG_ENV_OFFSET:
3838 Offset of environment data (variable area) to the
3839 beginning of flash memory; for instance, with bottom boot
3840 type flash chips the second sector can be used: the offset
3841 for this sector is given here.
3843 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3847 This is just another way to specify the start address of
3848 the flash sector containing the environment (instead of
3851 - CONFIG_ENV_SECT_SIZE:
3853 Size of the sector containing the environment.
3856 b) Sometimes flash chips have few, equal sized, BIG sectors.
3857 In such a case you don't want to spend a whole sector for
3862 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3863 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3864 of this flash sector for the environment. This saves
3865 memory for the RAM copy of the environment.
3867 It may also save flash memory if you decide to use this
3868 when your environment is "embedded" within U-Boot code,
3869 since then the remainder of the flash sector could be used
3870 for U-Boot code. It should be pointed out that this is
3871 STRONGLY DISCOURAGED from a robustness point of view:
3872 updating the environment in flash makes it always
3873 necessary to erase the WHOLE sector. If something goes
3874 wrong before the contents has been restored from a copy in
3875 RAM, your target system will be dead.
3877 - CONFIG_ENV_ADDR_REDUND
3878 CONFIG_ENV_SIZE_REDUND
3880 These settings describe a second storage area used to hold
3881 a redundant copy of the environment data, so that there is
3882 a valid backup copy in case there is a power failure during
3883 a "saveenv" operation.
3885 BE CAREFUL! Any changes to the flash layout, and some changes to the
3886 source code will make it necessary to adapt <board>/u-boot.lds*
3890 - CONFIG_ENV_IS_IN_NVRAM:
3892 Define this if you have some non-volatile memory device
3893 (NVRAM, battery buffered SRAM) which you want to use for the
3899 These two #defines are used to determine the memory area you
3900 want to use for environment. It is assumed that this memory
3901 can just be read and written to, without any special
3904 BE CAREFUL! The first access to the environment happens quite early
3905 in U-Boot initalization (when we try to get the setting of for the
3906 console baudrate). You *MUST* have mapped your NVRAM area then, or
3909 Please note that even with NVRAM we still use a copy of the
3910 environment in RAM: we could work on NVRAM directly, but we want to
3911 keep settings there always unmodified except somebody uses "saveenv"
3912 to save the current settings.
3915 - CONFIG_ENV_IS_IN_EEPROM:
3917 Use this if you have an EEPROM or similar serial access
3918 device and a driver for it.
3920 - CONFIG_ENV_OFFSET:
3923 These two #defines specify the offset and size of the
3924 environment area within the total memory of your EEPROM.
3926 - CONFIG_SYS_I2C_EEPROM_ADDR:
3927 If defined, specified the chip address of the EEPROM device.
3928 The default address is zero.
3930 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3931 If defined, the number of bits used to address bytes in a
3932 single page in the EEPROM device. A 64 byte page, for example
3933 would require six bits.
3935 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3936 If defined, the number of milliseconds to delay between
3937 page writes. The default is zero milliseconds.
3939 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3940 The length in bytes of the EEPROM memory array address. Note
3941 that this is NOT the chip address length!
3943 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3944 EEPROM chips that implement "address overflow" are ones
3945 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3946 address and the extra bits end up in the "chip address" bit
3947 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3950 Note that we consider the length of the address field to
3951 still be one byte because the extra address bits are hidden
3952 in the chip address.
3954 - CONFIG_SYS_EEPROM_SIZE:
3955 The size in bytes of the EEPROM device.
3957 - CONFIG_ENV_EEPROM_IS_ON_I2C
3958 define this, if you have I2C and SPI activated, and your
3959 EEPROM, which holds the environment, is on the I2C bus.
3961 - CONFIG_I2C_ENV_EEPROM_BUS
3962 if you have an Environment on an EEPROM reached over
3963 I2C muxes, you can define here, how to reach this
3964 EEPROM. For example:
3966 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3968 EEPROM which holds the environment, is reached over
3969 a pca9547 i2c mux with address 0x70, channel 3.
3971 - CONFIG_ENV_IS_IN_DATAFLASH:
3973 Define this if you have a DataFlash memory device which you
3974 want to use for the environment.
3976 - CONFIG_ENV_OFFSET:
3980 These three #defines specify the offset and size of the
3981 environment area within the total memory of your DataFlash placed
3982 at the specified address.
3984 - CONFIG_ENV_IS_IN_REMOTE:
3986 Define this if you have a remote memory space which you
3987 want to use for the local device's environment.
3992 These two #defines specify the address and size of the
3993 environment area within the remote memory space. The
3994 local device can get the environment from remote memory
3995 space by SRIO or PCIE links.
3997 BE CAREFUL! For some special cases, the local device can not use
3998 "saveenv" command. For example, the local device will get the
3999 environment stored in a remote NOR flash by SRIO or PCIE link,
4000 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4002 - CONFIG_ENV_IS_IN_NAND:
4004 Define this if you have a NAND device which you want to use
4005 for the environment.
4007 - CONFIG_ENV_OFFSET:
4010 These two #defines specify the offset and size of the environment
4011 area within the first NAND device. CONFIG_ENV_OFFSET must be
4012 aligned to an erase block boundary.
4014 - CONFIG_ENV_OFFSET_REDUND (optional):
4016 This setting describes a second storage area of CONFIG_ENV_SIZE
4017 size used to hold a redundant copy of the environment data, so
4018 that there is a valid backup copy in case there is a power failure
4019 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4020 aligned to an erase block boundary.
4022 - CONFIG_ENV_RANGE (optional):
4024 Specifies the length of the region in which the environment
4025 can be written. This should be a multiple of the NAND device's
4026 block size. Specifying a range with more erase blocks than
4027 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4028 the range to be avoided.
4030 - CONFIG_ENV_OFFSET_OOB (optional):
4032 Enables support for dynamically retrieving the offset of the
4033 environment from block zero's out-of-band data. The
4034 "nand env.oob" command can be used to record this offset.
4035 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4036 using CONFIG_ENV_OFFSET_OOB.
4038 - CONFIG_NAND_ENV_DST
4040 Defines address in RAM to which the nand_spl code should copy the
4041 environment. If redundant environment is used, it will be copied to
4042 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4044 - CONFIG_ENV_IS_IN_UBI:
4046 Define this if you have an UBI volume that you want to use for the
4047 environment. This has the benefit of wear-leveling the environment
4048 accesses, which is important on NAND.
4050 - CONFIG_ENV_UBI_PART:
4052 Define this to a string that is the mtd partition containing the UBI.
4054 - CONFIG_ENV_UBI_VOLUME:
4056 Define this to the name of the volume that you want to store the
4059 - CONFIG_ENV_UBI_VOLUME_REDUND:
4061 Define this to the name of another volume to store a second copy of
4062 the environment in. This will enable redundant environments in UBI.
4063 It is assumed that both volumes are in the same MTD partition.
4065 - CONFIG_UBI_SILENCE_MSG
4066 - CONFIG_UBIFS_SILENCE_MSG
4068 You will probably want to define these to avoid a really noisy system
4069 when storing the env in UBI.
4071 - CONFIG_ENV_IS_IN_MMC:
4073 Define this if you have an MMC device which you want to use for the
4076 - CONFIG_SYS_MMC_ENV_DEV:
4078 Specifies which MMC device the environment is stored in.
4080 - CONFIG_SYS_MMC_ENV_PART (optional):
4082 Specifies which MMC partition the environment is stored in. If not
4083 set, defaults to partition 0, the user area. Common values might be
4084 1 (first MMC boot partition), 2 (second MMC boot partition).
4086 - CONFIG_ENV_OFFSET:
4089 These two #defines specify the offset and size of the environment
4090 area within the specified MMC device.
4092 If offset is positive (the usual case), it is treated as relative to
4093 the start of the MMC partition. If offset is negative, it is treated
4094 as relative to the end of the MMC partition. This can be useful if
4095 your board may be fitted with different MMC devices, which have
4096 different sizes for the MMC partitions, and you always want the
4097 environment placed at the very end of the partition, to leave the
4098 maximum possible space before it, to store other data.
4100 These two values are in units of bytes, but must be aligned to an
4101 MMC sector boundary.
4103 - CONFIG_ENV_OFFSET_REDUND (optional):
4105 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4106 hold a redundant copy of the environment data. This provides a
4107 valid backup copy in case the other copy is corrupted, e.g. due
4108 to a power failure during a "saveenv" operation.
4110 This value may also be positive or negative; this is handled in the
4111 same way as CONFIG_ENV_OFFSET.
4113 This value is also in units of bytes, but must also be aligned to
4114 an MMC sector boundary.
4116 - CONFIG_ENV_SIZE_REDUND (optional):
4118 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4119 set. If this value is set, it must be set to the same value as
4122 - CONFIG_SYS_SPI_INIT_OFFSET
4124 Defines offset to the initial SPI buffer area in DPRAM. The
4125 area is used at an early stage (ROM part) if the environment
4126 is configured to reside in the SPI EEPROM: We need a 520 byte
4127 scratch DPRAM area. It is used between the two initialization
4128 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4129 to be a good choice since it makes it far enough from the
4130 start of the data area as well as from the stack pointer.
4132 Please note that the environment is read-only until the monitor
4133 has been relocated to RAM and a RAM copy of the environment has been
4134 created; also, when using EEPROM you will have to use getenv_f()
4135 until then to read environment variables.
4137 The environment is protected by a CRC32 checksum. Before the monitor
4138 is relocated into RAM, as a result of a bad CRC you will be working
4139 with the compiled-in default environment - *silently*!!! [This is
4140 necessary, because the first environment variable we need is the
4141 "baudrate" setting for the console - if we have a bad CRC, we don't
4142 have any device yet where we could complain.]
4144 Note: once the monitor has been relocated, then it will complain if
4145 the default environment is used; a new CRC is computed as soon as you
4146 use the "saveenv" command to store a valid environment.
4148 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4149 Echo the inverted Ethernet link state to the fault LED.
4151 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4152 also needs to be defined.
4154 - CONFIG_SYS_FAULT_MII_ADDR:
4155 MII address of the PHY to check for the Ethernet link state.
4157 - CONFIG_NS16550_MIN_FUNCTIONS:
4158 Define this if you desire to only have use of the NS16550_init
4159 and NS16550_putc functions for the serial driver located at
4160 drivers/serial/ns16550.c. This option is useful for saving
4161 space for already greatly restricted images, including but not
4162 limited to NAND_SPL configurations.
4164 - CONFIG_DISPLAY_BOARDINFO
4165 Display information about the board that U-Boot is running on
4166 when U-Boot starts up. The board function checkboard() is called
4169 - CONFIG_DISPLAY_BOARDINFO_LATE
4170 Similar to the previous option, but display this information
4171 later, once stdio is running and output goes to the LCD, if
4174 Low Level (hardware related) configuration options:
4175 ---------------------------------------------------
4177 - CONFIG_SYS_CACHELINE_SIZE:
4178 Cache Line Size of the CPU.
4180 - CONFIG_SYS_DEFAULT_IMMR:
4181 Default address of the IMMR after system reset.
4183 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4184 and RPXsuper) to be able to adjust the position of
4185 the IMMR register after a reset.
4187 - CONFIG_SYS_CCSRBAR_DEFAULT:
4188 Default (power-on reset) physical address of CCSR on Freescale
4191 - CONFIG_SYS_CCSRBAR:
4192 Virtual address of CCSR. On a 32-bit build, this is typically
4193 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4195 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4196 for cross-platform code that uses that macro instead.
4198 - CONFIG_SYS_CCSRBAR_PHYS:
4199 Physical address of CCSR. CCSR can be relocated to a new
4200 physical address, if desired. In this case, this macro should
4201 be set to that address. Otherwise, it should be set to the
4202 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4203 is typically relocated on 36-bit builds. It is recommended
4204 that this macro be defined via the _HIGH and _LOW macros:
4206 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4207 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4209 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4210 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4211 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4212 used in assembly code, so it must not contain typecasts or
4213 integer size suffixes (e.g. "ULL").
4215 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4216 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4217 used in assembly code, so it must not contain typecasts or
4218 integer size suffixes (e.g. "ULL").
4220 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4221 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4222 forced to a value that ensures that CCSR is not relocated.
4224 - Floppy Disk Support:
4225 CONFIG_SYS_FDC_DRIVE_NUMBER
4227 the default drive number (default value 0)
4229 CONFIG_SYS_ISA_IO_STRIDE
4231 defines the spacing between FDC chipset registers
4234 CONFIG_SYS_ISA_IO_OFFSET
4236 defines the offset of register from address. It
4237 depends on which part of the data bus is connected to
4238 the FDC chipset. (default value 0)
4240 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4241 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4244 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4245 fdc_hw_init() is called at the beginning of the FDC
4246 setup. fdc_hw_init() must be provided by the board
4247 source code. It is used to make hardware dependant
4251 Most IDE controllers were designed to be connected with PCI
4252 interface. Only few of them were designed for AHB interface.
4253 When software is doing ATA command and data transfer to
4254 IDE devices through IDE-AHB controller, some additional
4255 registers accessing to these kind of IDE-AHB controller
4258 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4259 DO NOT CHANGE unless you know exactly what you're
4260 doing! (11-4) [MPC8xx/82xx systems only]
4262 - CONFIG_SYS_INIT_RAM_ADDR:
4264 Start address of memory area that can be used for
4265 initial data and stack; please note that this must be
4266 writable memory that is working WITHOUT special
4267 initialization, i. e. you CANNOT use normal RAM which
4268 will become available only after programming the
4269 memory controller and running certain initialization
4272 U-Boot uses the following memory types:
4273 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4274 - MPC824X: data cache
4275 - PPC4xx: data cache
4277 - CONFIG_SYS_GBL_DATA_OFFSET:
4279 Offset of the initial data structure in the memory
4280 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4281 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4282 data is located at the end of the available space
4283 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4284 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4285 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4286 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4289 On the MPC824X (or other systems that use the data
4290 cache for initial memory) the address chosen for
4291 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4292 point to an otherwise UNUSED address space between
4293 the top of RAM and the start of the PCI space.
4295 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4297 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4299 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4301 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4303 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4305 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4307 - CONFIG_SYS_OR_TIMING_SDRAM:
4310 - CONFIG_SYS_MAMR_PTA:
4311 periodic timer for refresh
4313 - CONFIG_SYS_DER: Debug Event Register (37-47)
4315 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4316 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4317 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4318 CONFIG_SYS_BR1_PRELIM:
4319 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4321 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4322 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4323 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4324 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4326 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4327 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4328 Machine Mode Register and Memory Periodic Timer
4329 Prescaler definitions (SDRAM timing)
4331 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4332 enable I2C microcode relocation patch (MPC8xx);
4333 define relocation offset in DPRAM [DSP2]
4335 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4336 enable SMC microcode relocation patch (MPC8xx);
4337 define relocation offset in DPRAM [SMC1]
4339 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4340 enable SPI microcode relocation patch (MPC8xx);
4341 define relocation offset in DPRAM [SCC4]
4343 - CONFIG_SYS_USE_OSCCLK:
4344 Use OSCM clock mode on MBX8xx board. Be careful,
4345 wrong setting might damage your board. Read
4346 doc/README.MBX before setting this variable!
4348 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4349 Offset of the bootmode word in DPRAM used by post
4350 (Power On Self Tests). This definition overrides
4351 #define'd default value in commproc.h resp.
4354 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4355 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4356 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4357 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4358 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4359 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4360 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4361 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4362 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4364 - CONFIG_PCI_DISABLE_PCIE:
4365 Disable PCI-Express on systems where it is supported but not
4368 - CONFIG_PCI_ENUM_ONLY
4369 Only scan through and get the devices on the busses.
4370 Don't do any setup work, presumably because someone or
4371 something has already done it, and we don't need to do it
4372 a second time. Useful for platforms that are pre-booted
4373 by coreboot or similar.
4375 - CONFIG_PCI_INDIRECT_BRIDGE:
4376 Enable support for indirect PCI bridges.
4379 Chip has SRIO or not
4382 Board has SRIO 1 port available
4385 Board has SRIO 2 port available
4387 - CONFIG_SRIO_PCIE_BOOT_MASTER
4388 Board can support master function for Boot from SRIO and PCIE
4390 - CONFIG_SYS_SRIOn_MEM_VIRT:
4391 Virtual Address of SRIO port 'n' memory region
4393 - CONFIG_SYS_SRIOn_MEM_PHYS:
4394 Physical Address of SRIO port 'n' memory region
4396 - CONFIG_SYS_SRIOn_MEM_SIZE:
4397 Size of SRIO port 'n' memory region
4399 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4400 Defined to tell the NAND controller that the NAND chip is using
4402 Not all NAND drivers use this symbol.
4403 Example of drivers that use it:
4404 - drivers/mtd/nand/ndfc.c
4405 - drivers/mtd/nand/mxc_nand.c
4407 - CONFIG_SYS_NDFC_EBC0_CFG
4408 Sets the EBC0_CFG register for the NDFC. If not defined
4409 a default value will be used.
4412 Get DDR timing information from an I2C EEPROM. Common
4413 with pluggable memory modules such as SODIMMs
4416 I2C address of the SPD EEPROM
4418 - CONFIG_SYS_SPD_BUS_NUM
4419 If SPD EEPROM is on an I2C bus other than the first
4420 one, specify here. Note that the value must resolve
4421 to something your driver can deal with.
4423 - CONFIG_SYS_DDR_RAW_TIMING
4424 Get DDR timing information from other than SPD. Common with
4425 soldered DDR chips onboard without SPD. DDR raw timing
4426 parameters are extracted from datasheet and hard-coded into
4427 header files or board specific files.
4429 - CONFIG_FSL_DDR_INTERACTIVE
4430 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4432 - CONFIG_SYS_83XX_DDR_USES_CS0
4433 Only for 83xx systems. If specified, then DDR should
4434 be configured using CS0 and CS1 instead of CS2 and CS3.
4436 - CONFIG_ETHER_ON_FEC[12]
4437 Define to enable FEC[12] on a 8xx series processor.
4439 - CONFIG_FEC[12]_PHY
4440 Define to the hardcoded PHY address which corresponds
4441 to the given FEC; i. e.
4442 #define CONFIG_FEC1_PHY 4
4443 means that the PHY with address 4 is connected to FEC1
4445 When set to -1, means to probe for first available.
4447 - CONFIG_FEC[12]_PHY_NORXERR
4448 The PHY does not have a RXERR line (RMII only).
4449 (so program the FEC to ignore it).
4452 Enable RMII mode for all FECs.
4453 Note that this is a global option, we can't
4454 have one FEC in standard MII mode and another in RMII mode.
4456 - CONFIG_CRC32_VERIFY
4457 Add a verify option to the crc32 command.
4460 => crc32 -v <address> <count> <crc32>
4462 Where address/count indicate a memory area
4463 and crc32 is the correct crc32 which the
4467 Add the "loopw" memory command. This only takes effect if
4468 the memory commands are activated globally (CONFIG_CMD_MEM).
4471 Add the "mdc" and "mwc" memory commands. These are cyclic
4476 This command will print 4 bytes (10,11,12,13) each 500 ms.
4478 => mwc.l 100 12345678 10
4479 This command will write 12345678 to address 100 all 10 ms.
4481 This only takes effect if the memory commands are activated
4482 globally (CONFIG_CMD_MEM).
4484 - CONFIG_SKIP_LOWLEVEL_INIT
4485 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4486 low level initializations (like setting up the memory
4487 controller) are omitted and/or U-Boot does not
4488 relocate itself into RAM.
4490 Normally this variable MUST NOT be defined. The only
4491 exception is when U-Boot is loaded (to RAM) by some
4492 other boot loader or by a debugger which performs
4493 these initializations itself.
4496 Modifies the behaviour of start.S when compiling a loader
4497 that is executed before the actual U-Boot. E.g. when
4498 compiling a NAND SPL.
4501 Modifies the behaviour of start.S when compiling a loader
4502 that is executed after the SPL and before the actual U-Boot.
4503 It is loaded by the SPL.
4505 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4506 Only for 85xx systems. If this variable is specified, the section
4507 .resetvec is not kept and the section .bootpg is placed in the
4508 previous 4k of the .text section.
4510 - CONFIG_ARCH_MAP_SYSMEM
4511 Generally U-Boot (and in particular the md command) uses
4512 effective address. It is therefore not necessary to regard
4513 U-Boot address as virtual addresses that need to be translated
4514 to physical addresses. However, sandbox requires this, since
4515 it maintains its own little RAM buffer which contains all
4516 addressable memory. This option causes some memory accesses
4517 to be mapped through map_sysmem() / unmap_sysmem().
4519 - CONFIG_USE_ARCH_MEMCPY
4520 CONFIG_USE_ARCH_MEMSET
4521 If these options are used a optimized version of memcpy/memset will
4522 be used if available. These functions may be faster under some
4523 conditions but may increase the binary size.
4525 - CONFIG_X86_RESET_VECTOR
4526 If defined, the x86 reset vector code is included. This is not
4527 needed when U-Boot is running from Coreboot.
4530 Defines the MPU clock speed (in MHz).
4532 NOTE : currently only supported on AM335x platforms.
4534 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4535 Enables the RTC32K OSC on AM33xx based plattforms
4537 Freescale QE/FMAN Firmware Support:
4538 -----------------------------------
4540 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4541 loading of "firmware", which is encoded in the QE firmware binary format.
4542 This firmware often needs to be loaded during U-Boot booting, so macros
4543 are used to identify the storage device (NOR flash, SPI, etc) and the address
4546 - CONFIG_SYS_FMAN_FW_ADDR
4547 The address in the storage device where the FMAN microcode is located. The
4548 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4551 - CONFIG_SYS_QE_FW_ADDR
4552 The address in the storage device where the QE microcode is located. The
4553 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4556 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4557 The maximum possible size of the firmware. The firmware binary format
4558 has a field that specifies the actual size of the firmware, but it
4559 might not be possible to read any part of the firmware unless some
4560 local storage is allocated to hold the entire firmware first.
4562 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4563 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4564 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4565 virtual address in NOR flash.
4567 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4568 Specifies that QE/FMAN firmware is located in NAND flash.
4569 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4571 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4572 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4573 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4575 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4576 Specifies that QE/FMAN firmware is located on the primary SPI
4577 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4579 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4580 Specifies that QE/FMAN firmware is located in the remote (master)
4581 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4582 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4583 window->master inbound window->master LAW->the ucode address in
4584 master's memory space.
4586 Building the Software:
4587 ======================
4589 Building U-Boot has been tested in several native build environments
4590 and in many different cross environments. Of course we cannot support
4591 all possibly existing versions of cross development tools in all
4592 (potentially obsolete) versions. In case of tool chain problems we
4593 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4594 which is extensively used to build and test U-Boot.
4596 If you are not using a native environment, it is assumed that you
4597 have GNU cross compiling tools available in your path. In this case,
4598 you must set the environment variable CROSS_COMPILE in your shell.
4599 Note that no changes to the Makefile or any other source files are
4600 necessary. For example using the ELDK on a 4xx CPU, please enter:
4602 $ CROSS_COMPILE=ppc_4xx-
4603 $ export CROSS_COMPILE
4605 Note: If you wish to generate Windows versions of the utilities in
4606 the tools directory you can use the MinGW toolchain
4607 (http://www.mingw.org). Set your HOST tools to the MinGW
4608 toolchain and execute 'make tools'. For example:
4610 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4612 Binaries such as tools/mkimage.exe will be created which can
4613 be executed on computers running Windows.
4615 U-Boot is intended to be simple to build. After installing the
4616 sources you must configure U-Boot for one specific board type. This
4621 where "NAME_config" is the name of one of the existing configu-
4622 rations; see boards.cfg for supported names.
4624 Note: for some board special configuration names may exist; check if
4625 additional information is available from the board vendor; for
4626 instance, the TQM823L systems are available without (standard)
4627 or with LCD support. You can select such additional "features"
4628 when choosing the configuration, i. e.
4631 - will configure for a plain TQM823L, i. e. no LCD support
4633 make TQM823L_LCD_config
4634 - will configure for a TQM823L with U-Boot console on LCD
4639 Finally, type "make all", and you should get some working U-Boot
4640 images ready for download to / installation on your system:
4642 - "u-boot.bin" is a raw binary image
4643 - "u-boot" is an image in ELF binary format
4644 - "u-boot.srec" is in Motorola S-Record format
4646 By default the build is performed locally and the objects are saved
4647 in the source directory. One of the two methods can be used to change
4648 this behavior and build U-Boot to some external directory:
4650 1. Add O= to the make command line invocations:
4652 make O=/tmp/build distclean
4653 make O=/tmp/build NAME_config
4654 make O=/tmp/build all
4656 2. Set environment variable BUILD_DIR to point to the desired location:
4658 export BUILD_DIR=/tmp/build
4663 Note that the command line "O=" setting overrides the BUILD_DIR environment
4667 Please be aware that the Makefiles assume you are using GNU make, so
4668 for instance on NetBSD you might need to use "gmake" instead of
4672 If the system board that you have is not listed, then you will need
4673 to port U-Boot to your hardware platform. To do this, follow these
4676 1. Add a new configuration option for your board to the toplevel
4677 "boards.cfg" file, using the existing entries as examples.
4678 Follow the instructions there to keep the boards in order.
4679 2. Create a new directory to hold your board specific code. Add any
4680 files you need. In your board directory, you will need at least
4681 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4682 3. Create a new configuration file "include/configs/<board>.h" for
4684 3. If you're porting U-Boot to a new CPU, then also create a new
4685 directory to hold your CPU specific code. Add any files you need.
4686 4. Run "make <board>_config" with your new name.
4687 5. Type "make", and you should get a working "u-boot.srec" file
4688 to be installed on your target system.
4689 6. Debug and solve any problems that might arise.
4690 [Of course, this last step is much harder than it sounds.]
4693 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4694 ==============================================================
4696 If you have modified U-Boot sources (for instance added a new board
4697 or support for new devices, a new CPU, etc.) you are expected to
4698 provide feedback to the other developers. The feedback normally takes
4699 the form of a "patch", i. e. a context diff against a certain (latest
4700 official or latest in the git repository) version of U-Boot sources.
4702 But before you submit such a patch, please verify that your modifi-
4703 cation did not break existing code. At least make sure that *ALL* of
4704 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4705 just run the "MAKEALL" script, which will configure and build U-Boot
4706 for ALL supported system. Be warned, this will take a while. You can
4707 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4708 environment variable to the script, i. e. to use the ELDK cross tools
4711 CROSS_COMPILE=ppc_8xx- MAKEALL
4713 or to build on a native PowerPC system you can type
4715 CROSS_COMPILE=' ' MAKEALL
4717 When using the MAKEALL script, the default behaviour is to build
4718 U-Boot in the source directory. This location can be changed by
4719 setting the BUILD_DIR environment variable. Also, for each target
4720 built, the MAKEALL script saves two log files (<target>.ERR and
4721 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4722 location can be changed by setting the MAKEALL_LOGDIR environment
4723 variable. For example:
4725 export BUILD_DIR=/tmp/build
4726 export MAKEALL_LOGDIR=/tmp/log
4727 CROSS_COMPILE=ppc_8xx- MAKEALL
4729 With the above settings build objects are saved in the /tmp/build,
4730 log files are saved in the /tmp/log and the source tree remains clean
4731 during the whole build process.
4734 See also "U-Boot Porting Guide" below.
4737 Monitor Commands - Overview:
4738 ============================
4740 go - start application at address 'addr'
4741 run - run commands in an environment variable
4742 bootm - boot application image from memory
4743 bootp - boot image via network using BootP/TFTP protocol
4744 bootz - boot zImage from memory
4745 tftpboot- boot image via network using TFTP protocol
4746 and env variables "ipaddr" and "serverip"
4747 (and eventually "gatewayip")
4748 tftpput - upload a file via network using TFTP protocol
4749 rarpboot- boot image via network using RARP/TFTP protocol
4750 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4751 loads - load S-Record file over serial line
4752 loadb - load binary file over serial line (kermit mode)
4754 mm - memory modify (auto-incrementing)
4755 nm - memory modify (constant address)
4756 mw - memory write (fill)
4758 cmp - memory compare
4759 crc32 - checksum calculation
4760 i2c - I2C sub-system
4761 sspi - SPI utility commands
4762 base - print or set address offset
4763 printenv- print environment variables
4764 setenv - set environment variables
4765 saveenv - save environment variables to persistent storage
4766 protect - enable or disable FLASH write protection
4767 erase - erase FLASH memory
4768 flinfo - print FLASH memory information
4769 nand - NAND memory operations (see doc/README.nand)
4770 bdinfo - print Board Info structure
4771 iminfo - print header information for application image
4772 coninfo - print console devices and informations
4773 ide - IDE sub-system
4774 loop - infinite loop on address range
4775 loopw - infinite write loop on address range
4776 mtest - simple RAM test
4777 icache - enable or disable instruction cache
4778 dcache - enable or disable data cache
4779 reset - Perform RESET of the CPU
4780 echo - echo args to console
4781 version - print monitor version
4782 help - print online help
4783 ? - alias for 'help'
4786 Monitor Commands - Detailed Description:
4787 ========================================
4791 For now: just type "help <command>".
4794 Environment Variables:
4795 ======================
4797 U-Boot supports user configuration using Environment Variables which
4798 can be made persistent by saving to Flash memory.
4800 Environment Variables are set using "setenv", printed using
4801 "printenv", and saved to Flash using "saveenv". Using "setenv"
4802 without a value can be used to delete a variable from the
4803 environment. As long as you don't save the environment you are
4804 working with an in-memory copy. In case the Flash area containing the
4805 environment is erased by accident, a default environment is provided.
4807 Some configuration options can be set using Environment Variables.
4809 List of environment variables (most likely not complete):
4811 baudrate - see CONFIG_BAUDRATE
4813 bootdelay - see CONFIG_BOOTDELAY
4815 bootcmd - see CONFIG_BOOTCOMMAND
4817 bootargs - Boot arguments when booting an RTOS image
4819 bootfile - Name of the image to load with TFTP
4821 bootm_low - Memory range available for image processing in the bootm
4822 command can be restricted. This variable is given as
4823 a hexadecimal number and defines lowest address allowed
4824 for use by the bootm command. See also "bootm_size"
4825 environment variable. Address defined by "bootm_low" is
4826 also the base of the initial memory mapping for the Linux
4827 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4830 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4831 This variable is given as a hexadecimal number and it
4832 defines the size of the memory region starting at base
4833 address bootm_low that is accessible by the Linux kernel
4834 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4835 as the default value if it is defined, and bootm_size is
4838 bootm_size - Memory range available for image processing in the bootm
4839 command can be restricted. This variable is given as
4840 a hexadecimal number and defines the size of the region
4841 allowed for use by the bootm command. See also "bootm_low"
4842 environment variable.
4844 updatefile - Location of the software update file on a TFTP server, used
4845 by the automatic software update feature. Please refer to
4846 documentation in doc/README.update for more details.
4848 autoload - if set to "no" (any string beginning with 'n'),
4849 "bootp" will just load perform a lookup of the
4850 configuration from the BOOTP server, but not try to
4851 load any image using TFTP
4853 autostart - if set to "yes", an image loaded using the "bootp",
4854 "rarpboot", "tftpboot" or "diskboot" commands will
4855 be automatically started (by internally calling
4858 If set to "no", a standalone image passed to the
4859 "bootm" command will be copied to the load address
4860 (and eventually uncompressed), but NOT be started.
4861 This can be used to load and uncompress arbitrary
4864 fdt_high - if set this restricts the maximum address that the
4865 flattened device tree will be copied into upon boot.
4866 For example, if you have a system with 1 GB memory
4867 at physical address 0x10000000, while Linux kernel
4868 only recognizes the first 704 MB as low memory, you
4869 may need to set fdt_high as 0x3C000000 to have the
4870 device tree blob be copied to the maximum address
4871 of the 704 MB low memory, so that Linux kernel can
4872 access it during the boot procedure.
4874 If this is set to the special value 0xFFFFFFFF then
4875 the fdt will not be copied at all on boot. For this
4876 to work it must reside in writable memory, have
4877 sufficient padding on the end of it for u-boot to
4878 add the information it needs into it, and the memory
4879 must be accessible by the kernel.
4881 fdtcontroladdr- if set this is the address of the control flattened
4882 device tree used by U-Boot when CONFIG_OF_CONTROL is
4885 i2cfast - (PPC405GP|PPC405EP only)
4886 if set to 'y' configures Linux I2C driver for fast
4887 mode (400kHZ). This environment variable is used in
4888 initialization code. So, for changes to be effective
4889 it must be saved and board must be reset.
4891 initrd_high - restrict positioning of initrd images:
4892 If this variable is not set, initrd images will be
4893 copied to the highest possible address in RAM; this
4894 is usually what you want since it allows for
4895 maximum initrd size. If for some reason you want to
4896 make sure that the initrd image is loaded below the
4897 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4898 variable to a value of "no" or "off" or "0".
4899 Alternatively, you can set it to a maximum upper
4900 address to use (U-Boot will still check that it
4901 does not overwrite the U-Boot stack and data).
4903 For instance, when you have a system with 16 MB
4904 RAM, and want to reserve 4 MB from use by Linux,
4905 you can do this by adding "mem=12M" to the value of
4906 the "bootargs" variable. However, now you must make
4907 sure that the initrd image is placed in the first
4908 12 MB as well - this can be done with
4910 setenv initrd_high 00c00000
4912 If you set initrd_high to 0xFFFFFFFF, this is an
4913 indication to U-Boot that all addresses are legal
4914 for the Linux kernel, including addresses in flash
4915 memory. In this case U-Boot will NOT COPY the
4916 ramdisk at all. This may be useful to reduce the
4917 boot time on your system, but requires that this
4918 feature is supported by your Linux kernel.
4920 ipaddr - IP address; needed for tftpboot command
4922 loadaddr - Default load address for commands like "bootp",
4923 "rarpboot", "tftpboot", "loadb" or "diskboot"
4925 loads_echo - see CONFIG_LOADS_ECHO
4927 serverip - TFTP server IP address; needed for tftpboot command
4929 bootretry - see CONFIG_BOOT_RETRY_TIME
4931 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4933 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4935 ethprime - controls which interface is used first.
4937 ethact - controls which interface is currently active.
4938 For example you can do the following
4940 => setenv ethact FEC
4941 => ping 192.168.0.1 # traffic sent on FEC
4942 => setenv ethact SCC
4943 => ping 10.0.0.1 # traffic sent on SCC
4945 ethrotate - When set to "no" U-Boot does not go through all
4946 available network interfaces.
4947 It just stays at the currently selected interface.
4949 netretry - When set to "no" each network operation will
4950 either succeed or fail without retrying.
4951 When set to "once" the network operation will
4952 fail when all the available network interfaces
4953 are tried once without success.
4954 Useful on scripts which control the retry operation
4957 npe_ucode - set load address for the NPE microcode
4959 silent_linux - If set then linux will be told to boot silently, by
4960 changing the console to be empty. If "yes" it will be
4961 made silent. If "no" it will not be made silent. If
4962 unset, then it will be made silent if the U-Boot console
4965 tftpsrcport - If this is set, the value is used for TFTP's
4968 tftpdstport - If this is set, the value is used for TFTP's UDP
4969 destination port instead of the Well Know Port 69.
4971 tftpblocksize - Block size to use for TFTP transfers; if not set,
4972 we use the TFTP server's default block size
4974 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4975 seconds, minimum value is 1000 = 1 second). Defines
4976 when a packet is considered to be lost so it has to
4977 be retransmitted. The default is 5000 = 5 seconds.
4978 Lowering this value may make downloads succeed
4979 faster in networks with high packet loss rates or
4980 with unreliable TFTP servers.
4982 vlan - When set to a value < 4095 the traffic over
4983 Ethernet is encapsulated/received over 802.1q
4986 The following image location variables contain the location of images
4987 used in booting. The "Image" column gives the role of the image and is
4988 not an environment variable name. The other columns are environment
4989 variable names. "File Name" gives the name of the file on a TFTP
4990 server, "RAM Address" gives the location in RAM the image will be
4991 loaded to, and "Flash Location" gives the image's address in NOR
4992 flash or offset in NAND flash.
4994 *Note* - these variables don't have to be defined for all boards, some
4995 boards currenlty use other variables for these purposes, and some
4996 boards use these variables for other purposes.
4998 Image File Name RAM Address Flash Location
4999 ----- --------- ----------- --------------
5000 u-boot u-boot u-boot_addr_r u-boot_addr
5001 Linux kernel bootfile kernel_addr_r kernel_addr
5002 device tree blob fdtfile fdt_addr_r fdt_addr
5003 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5005 The following environment variables may be used and automatically
5006 updated by the network boot commands ("bootp" and "rarpboot"),
5007 depending the information provided by your boot server:
5009 bootfile - see above
5010 dnsip - IP address of your Domain Name Server
5011 dnsip2 - IP address of your secondary Domain Name Server
5012 gatewayip - IP address of the Gateway (Router) to use
5013 hostname - Target hostname
5015 netmask - Subnet Mask
5016 rootpath - Pathname of the root filesystem on the NFS server
5017 serverip - see above
5020 There are two special Environment Variables:
5022 serial# - contains hardware identification information such
5023 as type string and/or serial number
5024 ethaddr - Ethernet address
5026 These variables can be set only once (usually during manufacturing of
5027 the board). U-Boot refuses to delete or overwrite these variables
5028 once they have been set once.
5031 Further special Environment Variables:
5033 ver - Contains the U-Boot version string as printed
5034 with the "version" command. This variable is
5035 readonly (see CONFIG_VERSION_VARIABLE).
5038 Please note that changes to some configuration parameters may take
5039 only effect after the next boot (yes, that's just like Windoze :-).
5042 Callback functions for environment variables:
5043 ---------------------------------------------
5045 For some environment variables, the behavior of u-boot needs to change
5046 when their values are changed. This functionailty allows functions to
5047 be associated with arbitrary variables. On creation, overwrite, or
5048 deletion, the callback will provide the opportunity for some side
5049 effect to happen or for the change to be rejected.
5051 The callbacks are named and associated with a function using the
5052 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5054 These callbacks are associated with variables in one of two ways. The
5055 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5056 in the board configuration to a string that defines a list of
5057 associations. The list must be in the following format:
5059 entry = variable_name[:callback_name]
5062 If the callback name is not specified, then the callback is deleted.
5063 Spaces are also allowed anywhere in the list.
5065 Callbacks can also be associated by defining the ".callbacks" variable
5066 with the same list format above. Any association in ".callbacks" will
5067 override any association in the static list. You can define
5068 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5069 ".callbacks" envirnoment variable in the default or embedded environment.
5072 Command Line Parsing:
5073 =====================
5075 There are two different command line parsers available with U-Boot:
5076 the old "simple" one, and the much more powerful "hush" shell:
5078 Old, simple command line parser:
5079 --------------------------------
5081 - supports environment variables (through setenv / saveenv commands)
5082 - several commands on one line, separated by ';'
5083 - variable substitution using "... ${name} ..." syntax
5084 - special characters ('$', ';') can be escaped by prefixing with '\',
5086 setenv bootcmd bootm \${address}
5087 - You can also escape text by enclosing in single apostrophes, for example:
5088 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5093 - similar to Bourne shell, with control structures like
5094 if...then...else...fi, for...do...done; while...do...done,
5095 until...do...done, ...
5096 - supports environment ("global") variables (through setenv / saveenv
5097 commands) and local shell variables (through standard shell syntax
5098 "name=value"); only environment variables can be used with "run"
5104 (1) If a command line (or an environment variable executed by a "run"
5105 command) contains several commands separated by semicolon, and
5106 one of these commands fails, then the remaining commands will be
5109 (2) If you execute several variables with one call to run (i. e.
5110 calling run with a list of variables as arguments), any failing
5111 command will cause "run" to terminate, i. e. the remaining
5112 variables are not executed.
5114 Note for Redundant Ethernet Interfaces:
5115 =======================================
5117 Some boards come with redundant Ethernet interfaces; U-Boot supports
5118 such configurations and is capable of automatic selection of a
5119 "working" interface when needed. MAC assignment works as follows:
5121 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5122 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5123 "eth1addr" (=>eth1), "eth2addr", ...
5125 If the network interface stores some valid MAC address (for instance
5126 in SROM), this is used as default address if there is NO correspon-
5127 ding setting in the environment; if the corresponding environment
5128 variable is set, this overrides the settings in the card; that means:
5130 o If the SROM has a valid MAC address, and there is no address in the
5131 environment, the SROM's address is used.
5133 o If there is no valid address in the SROM, and a definition in the
5134 environment exists, then the value from the environment variable is
5137 o If both the SROM and the environment contain a MAC address, and
5138 both addresses are the same, this MAC address is used.
5140 o If both the SROM and the environment contain a MAC address, and the
5141 addresses differ, the value from the environment is used and a
5144 o If neither SROM nor the environment contain a MAC address, an error
5147 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5148 will be programmed into hardware as part of the initialization process. This
5149 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5150 The naming convention is as follows:
5151 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5156 U-Boot is capable of booting (and performing other auxiliary operations on)
5157 images in two formats:
5159 New uImage format (FIT)
5160 -----------------------
5162 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5163 to Flattened Device Tree). It allows the use of images with multiple
5164 components (several kernels, ramdisks, etc.), with contents protected by
5165 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5171 Old image format is based on binary files which can be basically anything,
5172 preceded by a special header; see the definitions in include/image.h for
5173 details; basically, the header defines the following image properties:
5175 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5176 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5177 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5178 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5180 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5181 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5182 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5183 * Compression Type (uncompressed, gzip, bzip2)
5189 The header is marked by a special Magic Number, and both the header
5190 and the data portions of the image are secured against corruption by
5197 Although U-Boot should support any OS or standalone application
5198 easily, the main focus has always been on Linux during the design of
5201 U-Boot includes many features that so far have been part of some
5202 special "boot loader" code within the Linux kernel. Also, any
5203 "initrd" images to be used are no longer part of one big Linux image;
5204 instead, kernel and "initrd" are separate images. This implementation
5205 serves several purposes:
5207 - the same features can be used for other OS or standalone
5208 applications (for instance: using compressed images to reduce the
5209 Flash memory footprint)
5211 - it becomes much easier to port new Linux kernel versions because
5212 lots of low-level, hardware dependent stuff are done by U-Boot
5214 - the same Linux kernel image can now be used with different "initrd"
5215 images; of course this also means that different kernel images can
5216 be run with the same "initrd". This makes testing easier (you don't
5217 have to build a new "zImage.initrd" Linux image when you just
5218 change a file in your "initrd"). Also, a field-upgrade of the
5219 software is easier now.
5225 Porting Linux to U-Boot based systems:
5226 ---------------------------------------
5228 U-Boot cannot save you from doing all the necessary modifications to
5229 configure the Linux device drivers for use with your target hardware
5230 (no, we don't intend to provide a full virtual machine interface to
5233 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5235 Just make sure your machine specific header file (for instance
5236 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5237 Information structure as we define in include/asm-<arch>/u-boot.h,
5238 and make sure that your definition of IMAP_ADDR uses the same value
5239 as your U-Boot configuration in CONFIG_SYS_IMMR.
5242 Configuring the Linux kernel:
5243 -----------------------------
5245 No specific requirements for U-Boot. Make sure you have some root
5246 device (initial ramdisk, NFS) for your target system.
5249 Building a Linux Image:
5250 -----------------------
5252 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5253 not used. If you use recent kernel source, a new build target
5254 "uImage" will exist which automatically builds an image usable by
5255 U-Boot. Most older kernels also have support for a "pImage" target,
5256 which was introduced for our predecessor project PPCBoot and uses a
5257 100% compatible format.
5266 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5267 encapsulate a compressed Linux kernel image with header information,
5268 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5270 * build a standard "vmlinux" kernel image (in ELF binary format):
5272 * convert the kernel into a raw binary image:
5274 ${CROSS_COMPILE}-objcopy -O binary \
5275 -R .note -R .comment \
5276 -S vmlinux linux.bin
5278 * compress the binary image:
5282 * package compressed binary image for U-Boot:
5284 mkimage -A ppc -O linux -T kernel -C gzip \
5285 -a 0 -e 0 -n "Linux Kernel Image" \
5286 -d linux.bin.gz uImage
5289 The "mkimage" tool can also be used to create ramdisk images for use
5290 with U-Boot, either separated from the Linux kernel image, or
5291 combined into one file. "mkimage" encapsulates the images with a 64
5292 byte header containing information about target architecture,
5293 operating system, image type, compression method, entry points, time
5294 stamp, CRC32 checksums, etc.
5296 "mkimage" can be called in two ways: to verify existing images and
5297 print the header information, or to build new images.
5299 In the first form (with "-l" option) mkimage lists the information
5300 contained in the header of an existing U-Boot image; this includes
5301 checksum verification:
5303 tools/mkimage -l image
5304 -l ==> list image header information
5306 The second form (with "-d" option) is used to build a U-Boot image
5307 from a "data file" which is used as image payload:
5309 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5310 -n name -d data_file image
5311 -A ==> set architecture to 'arch'
5312 -O ==> set operating system to 'os'
5313 -T ==> set image type to 'type'
5314 -C ==> set compression type 'comp'
5315 -a ==> set load address to 'addr' (hex)
5316 -e ==> set entry point to 'ep' (hex)
5317 -n ==> set image name to 'name'
5318 -d ==> use image data from 'datafile'
5320 Right now, all Linux kernels for PowerPC systems use the same load
5321 address (0x00000000), but the entry point address depends on the
5324 - 2.2.x kernels have the entry point at 0x0000000C,
5325 - 2.3.x and later kernels have the entry point at 0x00000000.
5327 So a typical call to build a U-Boot image would read:
5329 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5330 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5331 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5332 > examples/uImage.TQM850L
5333 Image Name: 2.4.4 kernel for TQM850L
5334 Created: Wed Jul 19 02:34:59 2000
5335 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5336 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5337 Load Address: 0x00000000
5338 Entry Point: 0x00000000
5340 To verify the contents of the image (or check for corruption):
5342 -> tools/mkimage -l examples/uImage.TQM850L
5343 Image Name: 2.4.4 kernel for TQM850L
5344 Created: Wed Jul 19 02:34:59 2000
5345 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5346 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5347 Load Address: 0x00000000
5348 Entry Point: 0x00000000
5350 NOTE: for embedded systems where boot time is critical you can trade
5351 speed for memory and install an UNCOMPRESSED image instead: this
5352 needs more space in Flash, but boots much faster since it does not
5353 need to be uncompressed:
5355 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5356 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5357 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5358 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5359 > examples/uImage.TQM850L-uncompressed
5360 Image Name: 2.4.4 kernel for TQM850L
5361 Created: Wed Jul 19 02:34:59 2000
5362 Image Type: PowerPC Linux Kernel Image (uncompressed)
5363 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5364 Load Address: 0x00000000
5365 Entry Point: 0x00000000
5368 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5369 when your kernel is intended to use an initial ramdisk:
5371 -> tools/mkimage -n 'Simple Ramdisk Image' \
5372 > -A ppc -O linux -T ramdisk -C gzip \
5373 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5374 Image Name: Simple Ramdisk Image
5375 Created: Wed Jan 12 14:01:50 2000
5376 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5377 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5378 Load Address: 0x00000000
5379 Entry Point: 0x00000000
5381 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5382 option performs the converse operation of the mkimage's second form (the "-d"
5383 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5386 tools/dumpimage -i image -p position data_file
5387 -i ==> extract from the 'image' a specific 'data_file', \
5388 indexed by 'position'
5391 Installing a Linux Image:
5392 -------------------------
5394 To downloading a U-Boot image over the serial (console) interface,
5395 you must convert the image to S-Record format:
5397 objcopy -I binary -O srec examples/image examples/image.srec
5399 The 'objcopy' does not understand the information in the U-Boot
5400 image header, so the resulting S-Record file will be relative to
5401 address 0x00000000. To load it to a given address, you need to
5402 specify the target address as 'offset' parameter with the 'loads'
5405 Example: install the image to address 0x40100000 (which on the
5406 TQM8xxL is in the first Flash bank):
5408 => erase 40100000 401FFFFF
5414 ## Ready for S-Record download ...
5415 ~>examples/image.srec
5416 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5418 15989 15990 15991 15992
5419 [file transfer complete]
5421 ## Start Addr = 0x00000000
5424 You can check the success of the download using the 'iminfo' command;
5425 this includes a checksum verification so you can be sure no data
5426 corruption happened:
5430 ## Checking Image at 40100000 ...
5431 Image Name: 2.2.13 for initrd on TQM850L
5432 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5433 Data Size: 335725 Bytes = 327 kB = 0 MB
5434 Load Address: 00000000
5435 Entry Point: 0000000c
5436 Verifying Checksum ... OK
5442 The "bootm" command is used to boot an application that is stored in
5443 memory (RAM or Flash). In case of a Linux kernel image, the contents
5444 of the "bootargs" environment variable is passed to the kernel as
5445 parameters. You can check and modify this variable using the
5446 "printenv" and "setenv" commands:
5449 => printenv bootargs
5450 bootargs=root=/dev/ram
5452 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5454 => printenv bootargs
5455 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5458 ## Booting Linux kernel at 40020000 ...
5459 Image Name: 2.2.13 for NFS on TQM850L
5460 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5461 Data Size: 381681 Bytes = 372 kB = 0 MB
5462 Load Address: 00000000
5463 Entry Point: 0000000c
5464 Verifying Checksum ... OK
5465 Uncompressing Kernel Image ... OK
5466 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
5467 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5468 time_init: decrementer frequency = 187500000/60
5469 Calibrating delay loop... 49.77 BogoMIPS
5470 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5473 If you want to boot a Linux kernel with initial RAM disk, you pass
5474 the memory addresses of both the kernel and the initrd image (PPBCOOT
5475 format!) to the "bootm" command:
5477 => imi 40100000 40200000
5479 ## Checking Image at 40100000 ...
5480 Image Name: 2.2.13 for initrd on TQM850L
5481 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5482 Data Size: 335725 Bytes = 327 kB = 0 MB
5483 Load Address: 00000000
5484 Entry Point: 0000000c
5485 Verifying Checksum ... OK
5487 ## Checking Image at 40200000 ...
5488 Image Name: Simple Ramdisk Image
5489 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5490 Data Size: 566530 Bytes = 553 kB = 0 MB
5491 Load Address: 00000000
5492 Entry Point: 00000000
5493 Verifying Checksum ... OK
5495 => bootm 40100000 40200000
5496 ## Booting Linux kernel at 40100000 ...
5497 Image Name: 2.2.13 for initrd on TQM850L
5498 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5499 Data Size: 335725 Bytes = 327 kB = 0 MB
5500 Load Address: 00000000
5501 Entry Point: 0000000c
5502 Verifying Checksum ... OK
5503 Uncompressing Kernel Image ... OK
5504 ## Loading RAMDisk Image at 40200000 ...
5505 Image Name: Simple Ramdisk Image
5506 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5507 Data Size: 566530 Bytes = 553 kB = 0 MB
5508 Load Address: 00000000
5509 Entry Point: 00000000
5510 Verifying Checksum ... OK
5511 Loading Ramdisk ... OK
5512 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
5513 Boot arguments: root=/dev/ram
5514 time_init: decrementer frequency = 187500000/60
5515 Calibrating delay loop... 49.77 BogoMIPS
5517 RAMDISK: Compressed image found at block 0
5518 VFS: Mounted root (ext2 filesystem).
5522 Boot Linux and pass a flat device tree:
5525 First, U-Boot must be compiled with the appropriate defines. See the section
5526 titled "Linux Kernel Interface" above for a more in depth explanation. The
5527 following is an example of how to start a kernel and pass an updated
5533 oft=oftrees/mpc8540ads.dtb
5534 => tftp $oftaddr $oft
5535 Speed: 1000, full duplex
5537 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5538 Filename 'oftrees/mpc8540ads.dtb'.
5539 Load address: 0x300000
5542 Bytes transferred = 4106 (100a hex)
5543 => tftp $loadaddr $bootfile
5544 Speed: 1000, full duplex
5546 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5548 Load address: 0x200000
5549 Loading:############
5551 Bytes transferred = 1029407 (fb51f hex)
5556 => bootm $loadaddr - $oftaddr
5557 ## Booting image at 00200000 ...
5558 Image Name: Linux-2.6.17-dirty
5559 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5560 Data Size: 1029343 Bytes = 1005.2 kB
5561 Load Address: 00000000
5562 Entry Point: 00000000
5563 Verifying Checksum ... OK
5564 Uncompressing Kernel Image ... OK
5565 Booting using flat device tree at 0x300000
5566 Using MPC85xx ADS machine description
5567 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5571 More About U-Boot Image Types:
5572 ------------------------------
5574 U-Boot supports the following image types:
5576 "Standalone Programs" are directly runnable in the environment
5577 provided by U-Boot; it is expected that (if they behave
5578 well) you can continue to work in U-Boot after return from
5579 the Standalone Program.
5580 "OS Kernel Images" are usually images of some Embedded OS which
5581 will take over control completely. Usually these programs
5582 will install their own set of exception handlers, device
5583 drivers, set up the MMU, etc. - this means, that you cannot
5584 expect to re-enter U-Boot except by resetting the CPU.
5585 "RAMDisk Images" are more or less just data blocks, and their
5586 parameters (address, size) are passed to an OS kernel that is
5588 "Multi-File Images" contain several images, typically an OS
5589 (Linux) kernel image and one or more data images like
5590 RAMDisks. This construct is useful for instance when you want
5591 to boot over the network using BOOTP etc., where the boot
5592 server provides just a single image file, but you want to get
5593 for instance an OS kernel and a RAMDisk image.
5595 "Multi-File Images" start with a list of image sizes, each
5596 image size (in bytes) specified by an "uint32_t" in network
5597 byte order. This list is terminated by an "(uint32_t)0".
5598 Immediately after the terminating 0 follow the images, one by
5599 one, all aligned on "uint32_t" boundaries (size rounded up to
5600 a multiple of 4 bytes).
5602 "Firmware Images" are binary images containing firmware (like
5603 U-Boot or FPGA images) which usually will be programmed to
5606 "Script files" are command sequences that will be executed by
5607 U-Boot's command interpreter; this feature is especially
5608 useful when you configure U-Boot to use a real shell (hush)
5609 as command interpreter.
5611 Booting the Linux zImage:
5612 -------------------------
5614 On some platforms, it's possible to boot Linux zImage. This is done
5615 using the "bootz" command. The syntax of "bootz" command is the same
5616 as the syntax of "bootm" command.
5618 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5619 kernel with raw initrd images. The syntax is slightly different, the
5620 address of the initrd must be augmented by it's size, in the following
5621 format: "<initrd addres>:<initrd size>".
5627 One of the features of U-Boot is that you can dynamically load and
5628 run "standalone" applications, which can use some resources of
5629 U-Boot like console I/O functions or interrupt services.
5631 Two simple examples are included with the sources:
5636 'examples/hello_world.c' contains a small "Hello World" Demo
5637 application; it is automatically compiled when you build U-Boot.
5638 It's configured to run at address 0x00040004, so you can play with it
5642 ## Ready for S-Record download ...
5643 ~>examples/hello_world.srec
5644 1 2 3 4 5 6 7 8 9 10 11 ...
5645 [file transfer complete]
5647 ## Start Addr = 0x00040004
5649 => go 40004 Hello World! This is a test.
5650 ## Starting application at 0x00040004 ...
5661 Hit any key to exit ...
5663 ## Application terminated, rc = 0x0
5665 Another example, which demonstrates how to register a CPM interrupt
5666 handler with the U-Boot code, can be found in 'examples/timer.c'.
5667 Here, a CPM timer is set up to generate an interrupt every second.
5668 The interrupt service routine is trivial, just printing a '.'
5669 character, but this is just a demo program. The application can be
5670 controlled by the following keys:
5672 ? - print current values og the CPM Timer registers
5673 b - enable interrupts and start timer
5674 e - stop timer and disable interrupts
5675 q - quit application
5678 ## Ready for S-Record download ...
5679 ~>examples/timer.srec
5680 1 2 3 4 5 6 7 8 9 10 11 ...
5681 [file transfer complete]
5683 ## Start Addr = 0x00040004
5686 ## Starting application at 0x00040004 ...
5689 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5692 [q, b, e, ?] Set interval 1000000 us
5695 [q, b, e, ?] ........
5696 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5699 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5702 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5705 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5707 [q, b, e, ?] ...Stopping timer
5709 [q, b, e, ?] ## Application terminated, rc = 0x0
5715 Over time, many people have reported problems when trying to use the
5716 "minicom" terminal emulation program for serial download. I (wd)
5717 consider minicom to be broken, and recommend not to use it. Under
5718 Unix, I recommend to use C-Kermit for general purpose use (and
5719 especially for kermit binary protocol download ("loadb" command), and
5720 use "cu" for S-Record download ("loads" command). See
5721 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5722 for help with kermit.
5725 Nevertheless, if you absolutely want to use it try adding this
5726 configuration to your "File transfer protocols" section:
5728 Name Program Name U/D FullScr IO-Red. Multi
5729 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5730 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5736 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5737 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5739 Building requires a cross environment; it is known to work on
5740 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5741 need gmake since the Makefiles are not compatible with BSD make).
5742 Note that the cross-powerpc package does not install include files;
5743 attempting to build U-Boot will fail because <machine/ansi.h> is
5744 missing. This file has to be installed and patched manually:
5746 # cd /usr/pkg/cross/powerpc-netbsd/include
5748 # ln -s powerpc machine
5749 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5750 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5752 Native builds *don't* work due to incompatibilities between native
5753 and U-Boot include files.
5755 Booting assumes that (the first part of) the image booted is a
5756 stage-2 loader which in turn loads and then invokes the kernel
5757 proper. Loader sources will eventually appear in the NetBSD source
5758 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5759 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5762 Implementation Internals:
5763 =========================
5765 The following is not intended to be a complete description of every
5766 implementation detail. However, it should help to understand the
5767 inner workings of U-Boot and make it easier to port it to custom
5771 Initial Stack, Global Data:
5772 ---------------------------
5774 The implementation of U-Boot is complicated by the fact that U-Boot
5775 starts running out of ROM (flash memory), usually without access to
5776 system RAM (because the memory controller is not initialized yet).
5777 This means that we don't have writable Data or BSS segments, and BSS
5778 is not initialized as zero. To be able to get a C environment working
5779 at all, we have to allocate at least a minimal stack. Implementation
5780 options for this are defined and restricted by the CPU used: Some CPU
5781 models provide on-chip memory (like the IMMR area on MPC8xx and
5782 MPC826x processors), on others (parts of) the data cache can be
5783 locked as (mis-) used as memory, etc.
5785 Chris Hallinan posted a good summary of these issues to the
5786 U-Boot mailing list:
5788 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5789 From: "Chris Hallinan" <clh@net1plus.com>
5790 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5793 Correct me if I'm wrong, folks, but the way I understand it
5794 is this: Using DCACHE as initial RAM for Stack, etc, does not
5795 require any physical RAM backing up the cache. The cleverness
5796 is that the cache is being used as a temporary supply of
5797 necessary storage before the SDRAM controller is setup. It's
5798 beyond the scope of this list to explain the details, but you
5799 can see how this works by studying the cache architecture and
5800 operation in the architecture and processor-specific manuals.
5802 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5803 is another option for the system designer to use as an
5804 initial stack/RAM area prior to SDRAM being available. Either
5805 option should work for you. Using CS 4 should be fine if your
5806 board designers haven't used it for something that would
5807 cause you grief during the initial boot! It is frequently not
5810 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5811 with your processor/board/system design. The default value
5812 you will find in any recent u-boot distribution in
5813 walnut.h should work for you. I'd set it to a value larger
5814 than your SDRAM module. If you have a 64MB SDRAM module, set
5815 it above 400_0000. Just make sure your board has no resources
5816 that are supposed to respond to that address! That code in
5817 start.S has been around a while and should work as is when
5818 you get the config right.
5823 It is essential to remember this, since it has some impact on the C
5824 code for the initialization procedures:
5826 * Initialized global data (data segment) is read-only. Do not attempt
5829 * Do not use any uninitialized global data (or implicitely initialized
5830 as zero data - BSS segment) at all - this is undefined, initiali-
5831 zation is performed later (when relocating to RAM).
5833 * Stack space is very limited. Avoid big data buffers or things like
5836 Having only the stack as writable memory limits means we cannot use
5837 normal global data to share information beween the code. But it
5838 turned out that the implementation of U-Boot can be greatly
5839 simplified by making a global data structure (gd_t) available to all
5840 functions. We could pass a pointer to this data as argument to _all_
5841 functions, but this would bloat the code. Instead we use a feature of
5842 the GCC compiler (Global Register Variables) to share the data: we
5843 place a pointer (gd) to the global data into a register which we
5844 reserve for this purpose.
5846 When choosing a register for such a purpose we are restricted by the
5847 relevant (E)ABI specifications for the current architecture, and by
5848 GCC's implementation.
5850 For PowerPC, the following registers have specific use:
5852 R2: reserved for system use
5853 R3-R4: parameter passing and return values
5854 R5-R10: parameter passing
5855 R13: small data area pointer
5859 (U-Boot also uses R12 as internal GOT pointer. r12
5860 is a volatile register so r12 needs to be reset when
5861 going back and forth between asm and C)
5863 ==> U-Boot will use R2 to hold a pointer to the global data
5865 Note: on PPC, we could use a static initializer (since the
5866 address of the global data structure is known at compile time),
5867 but it turned out that reserving a register results in somewhat
5868 smaller code - although the code savings are not that big (on
5869 average for all boards 752 bytes for the whole U-Boot image,
5870 624 text + 127 data).
5872 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5873 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5875 ==> U-Boot will use P3 to hold a pointer to the global data
5877 On ARM, the following registers are used:
5879 R0: function argument word/integer result
5880 R1-R3: function argument word
5881 R9: platform specific
5882 R10: stack limit (used only if stack checking is enabled)
5883 R11: argument (frame) pointer
5884 R12: temporary workspace
5887 R15: program counter
5889 ==> U-Boot will use R9 to hold a pointer to the global data
5891 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5893 On Nios II, the ABI is documented here:
5894 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5896 ==> U-Boot will use gp to hold a pointer to the global data
5898 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5899 to access small data sections, so gp is free.
5901 On NDS32, the following registers are used:
5903 R0-R1: argument/return
5905 R15: temporary register for assembler
5906 R16: trampoline register
5907 R28: frame pointer (FP)
5908 R29: global pointer (GP)
5909 R30: link register (LP)
5910 R31: stack pointer (SP)
5911 PC: program counter (PC)
5913 ==> U-Boot will use R10 to hold a pointer to the global data
5915 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5916 or current versions of GCC may "optimize" the code too much.
5921 U-Boot runs in system state and uses physical addresses, i.e. the
5922 MMU is not used either for address mapping nor for memory protection.
5924 The available memory is mapped to fixed addresses using the memory
5925 controller. In this process, a contiguous block is formed for each
5926 memory type (Flash, SDRAM, SRAM), even when it consists of several
5927 physical memory banks.
5929 U-Boot is installed in the first 128 kB of the first Flash bank (on
5930 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5931 booting and sizing and initializing DRAM, the code relocates itself
5932 to the upper end of DRAM. Immediately below the U-Boot code some
5933 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5934 configuration setting]. Below that, a structure with global Board
5935 Info data is placed, followed by the stack (growing downward).
5937 Additionally, some exception handler code is copied to the low 8 kB
5938 of DRAM (0x00000000 ... 0x00001FFF).
5940 So a typical memory configuration with 16 MB of DRAM could look like
5943 0x0000 0000 Exception Vector code
5946 0x0000 2000 Free for Application Use
5952 0x00FB FF20 Monitor Stack (Growing downward)
5953 0x00FB FFAC Board Info Data and permanent copy of global data
5954 0x00FC 0000 Malloc Arena
5957 0x00FE 0000 RAM Copy of Monitor Code
5958 ... eventually: LCD or video framebuffer
5959 ... eventually: pRAM (Protected RAM - unchanged by reset)
5960 0x00FF FFFF [End of RAM]
5963 System Initialization:
5964 ----------------------
5966 In the reset configuration, U-Boot starts at the reset entry point
5967 (on most PowerPC systems at address 0x00000100). Because of the reset
5968 configuration for CS0# this is a mirror of the onboard Flash memory.
5969 To be able to re-map memory U-Boot then jumps to its link address.
5970 To be able to implement the initialization code in C, a (small!)
5971 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5972 which provide such a feature like MPC8xx or MPC8260), or in a locked
5973 part of the data cache. After that, U-Boot initializes the CPU core,
5974 the caches and the SIU.
5976 Next, all (potentially) available memory banks are mapped using a
5977 preliminary mapping. For example, we put them on 512 MB boundaries
5978 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5979 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5980 programmed for SDRAM access. Using the temporary configuration, a
5981 simple memory test is run that determines the size of the SDRAM
5984 When there is more than one SDRAM bank, and the banks are of
5985 different size, the largest is mapped first. For equal size, the first
5986 bank (CS2#) is mapped first. The first mapping is always for address
5987 0x00000000, with any additional banks following immediately to create
5988 contiguous memory starting from 0.
5990 Then, the monitor installs itself at the upper end of the SDRAM area
5991 and allocates memory for use by malloc() and for the global Board
5992 Info data; also, the exception vector code is copied to the low RAM
5993 pages, and the final stack is set up.
5995 Only after this relocation will you have a "normal" C environment;
5996 until that you are restricted in several ways, mostly because you are
5997 running from ROM, and because the code will have to be relocated to a
6001 U-Boot Porting Guide:
6002 ----------------------
6004 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6008 int main(int argc, char *argv[])
6010 sighandler_t no_more_time;
6012 signal(SIGALRM, no_more_time);
6013 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6015 if (available_money > available_manpower) {
6016 Pay consultant to port U-Boot;
6020 Download latest U-Boot source;
6022 Subscribe to u-boot mailing list;
6025 email("Hi, I am new to U-Boot, how do I get started?");
6028 Read the README file in the top level directory;
6029 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6030 Read applicable doc/*.README;
6031 Read the source, Luke;
6032 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6035 if (available_money > toLocalCurrency ($2500))
6038 Add a lot of aggravation and time;
6040 if (a similar board exists) { /* hopefully... */
6041 cp -a board/<similar> board/<myboard>
6042 cp include/configs/<similar>.h include/configs/<myboard>.h
6044 Create your own board support subdirectory;
6045 Create your own board include/configs/<myboard>.h file;
6047 Edit new board/<myboard> files
6048 Edit new include/configs/<myboard>.h
6053 Add / modify source code;
6057 email("Hi, I am having problems...");
6059 Send patch file to the U-Boot email list;
6060 if (reasonable critiques)
6061 Incorporate improvements from email list code review;
6063 Defend code as written;
6069 void no_more_time (int sig)
6078 All contributions to U-Boot should conform to the Linux kernel
6079 coding style; see the file "Documentation/CodingStyle" and the script
6080 "scripts/Lindent" in your Linux kernel source directory.
6082 Source files originating from a different project (for example the
6083 MTD subsystem) are generally exempt from these guidelines and are not
6084 reformated to ease subsequent migration to newer versions of those
6087 Please note that U-Boot is implemented in C (and to some small parts in
6088 Assembler); no C++ is used, so please do not use C++ style comments (//)
6091 Please also stick to the following formatting rules:
6092 - remove any trailing white space
6093 - use TAB characters for indentation and vertical alignment, not spaces
6094 - make sure NOT to use DOS '\r\n' line feeds
6095 - do not add more than 2 consecutive empty lines to source files
6096 - do not add trailing empty lines to source files
6098 Submissions which do not conform to the standards may be returned
6099 with a request to reformat the changes.
6105 Since the number of patches for U-Boot is growing, we need to
6106 establish some rules. Submissions which do not conform to these rules
6107 may be rejected, even when they contain important and valuable stuff.
6109 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6111 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6112 see http://lists.denx.de/mailman/listinfo/u-boot
6114 When you send a patch, please include the following information with
6117 * For bug fixes: a description of the bug and how your patch fixes
6118 this bug. Please try to include a way of demonstrating that the
6119 patch actually fixes something.
6121 * For new features: a description of the feature and your
6124 * A CHANGELOG entry as plaintext (separate from the patch)
6126 * For major contributions, your entry to the CREDITS file
6128 * When you add support for a new board, don't forget to add a
6129 maintainer e-mail address to the boards.cfg file, too.
6131 * If your patch adds new configuration options, don't forget to
6132 document these in the README file.
6134 * The patch itself. If you are using git (which is *strongly*
6135 recommended) you can easily generate the patch using the
6136 "git format-patch". If you then use "git send-email" to send it to
6137 the U-Boot mailing list, you will avoid most of the common problems
6138 with some other mail clients.
6140 If you cannot use git, use "diff -purN OLD NEW". If your version of
6141 diff does not support these options, then get the latest version of
6144 The current directory when running this command shall be the parent
6145 directory of the U-Boot source tree (i. e. please make sure that
6146 your patch includes sufficient directory information for the
6149 We prefer patches as plain text. MIME attachments are discouraged,
6150 and compressed attachments must not be used.
6152 * If one logical set of modifications affects or creates several
6153 files, all these changes shall be submitted in a SINGLE patch file.
6155 * Changesets that contain different, unrelated modifications shall be
6156 submitted as SEPARATE patches, one patch per changeset.
6161 * Before sending the patch, run the MAKEALL script on your patched
6162 source tree and make sure that no errors or warnings are reported
6163 for any of the boards.
6165 * Keep your modifications to the necessary minimum: A patch
6166 containing several unrelated changes or arbitrary reformats will be
6167 returned with a request to re-formatting / split it.
6169 * If you modify existing code, make sure that your new code does not
6170 add to the memory footprint of the code ;-) Small is beautiful!
6171 When adding new features, these should compile conditionally only
6172 (using #ifdef), and the resulting code with the new feature
6173 disabled must not need more memory than the old code without your
6176 * Remember that there is a size limit of 100 kB per message on the
6177 u-boot mailing list. Bigger patches will be moderated. If they are
6178 reasonable and not too big, they will be acknowledged. But patches
6179 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob