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.
270 U-Boot can be built natively to run on a Linux host using the 'sandbox'
271 board. This allows feature development which is not board- or architecture-
272 specific to be undertaken on a native platform. The sandbox is also used to
273 run some of U-Boot's tests.
275 See board/sandbox/sandbox/README.sandbox for more details.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Board flavour: (if CONFIG_MPC8260ADS is defined)
327 CONFIG_SYS_8260ADS - original MPC8260ADS
328 CONFIG_SYS_8266ADS - MPC8266ADS
329 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
330 CONFIG_SYS_8272ADS - MPC8272ADS
332 - Marvell Family Member
333 CONFIG_SYS_MVFS - define it if you want to enable
334 multiple fs option at one time
335 for marvell soc family
337 - MPC824X Family Member (if CONFIG_MPC824X is defined)
338 Define exactly one of
339 CONFIG_MPC8240, CONFIG_MPC8245
341 - 8xx CPU Options: (if using an MPC8xx CPU)
342 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
343 get_gclk_freq() cannot work
344 e.g. if there is no 32KHz
345 reference PIT/RTC clock
346 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
349 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
350 CONFIG_SYS_8xx_CPUCLK_MIN
351 CONFIG_SYS_8xx_CPUCLK_MAX
352 CONFIG_8xx_CPUCLK_DEFAULT
353 See doc/README.MPC866
355 CONFIG_SYS_MEASURE_CPUCLK
357 Define this to measure the actual CPU clock instead
358 of relying on the correctness of the configured
359 values. Mostly useful for board bringup to make sure
360 the PLL is locked at the intended frequency. Note
361 that this requires a (stable) reference clock (32 kHz
362 RTC clock or CONFIG_SYS_8XX_XIN)
364 CONFIG_SYS_DELAYED_ICACHE
366 Define this option if you want to enable the
367 ICache only when Code runs from RAM.
372 Specifies that the core is a 64-bit PowerPC implementation (implements
373 the "64" category of the Power ISA). This is necessary for ePAPR
374 compliance, among other possible reasons.
376 CONFIG_SYS_FSL_TBCLK_DIV
378 Defines the core time base clock divider ratio compared to the
379 system clock. On most PQ3 devices this is 8, on newer QorIQ
380 devices it can be 16 or 32. The ratio varies from SoC to Soc.
382 CONFIG_SYS_FSL_PCIE_COMPAT
384 Defines the string to utilize when trying to match PCIe device
385 tree nodes for the given platform.
387 CONFIG_SYS_PPC_E500_DEBUG_TLB
389 Enables a temporary TLB entry to be used during boot to work
390 around limitations in e500v1 and e500v2 external debugger
391 support. This reduces the portions of the boot code where
392 breakpoints and single stepping do not work. The value of this
393 symbol should be set to the TLB1 entry to be used for this
396 CONFIG_SYS_FSL_ERRATUM_A004510
398 Enables a workaround for erratum A004510. If set,
399 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
400 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
402 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
405 Defines one or two SoC revisions (low 8 bits of SVR)
406 for which the A004510 workaround should be applied.
408 The rest of SVR is either not relevant to the decision
409 of whether the erratum is present (e.g. p2040 versus
410 p2041) or is implied by the build target, which controls
411 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
413 See Freescale App Note 4493 for more information about
416 CONFIG_A003399_NOR_WORKAROUND
417 Enables a workaround for IFC erratum A003399. It is only
418 requred during NOR boot.
420 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
422 This is the value to write into CCSR offset 0x18600
423 according to the A004510 workaround.
425 CONFIG_SYS_FSL_DSP_DDR_ADDR
426 This value denotes start offset of DDR memory which is
427 connected exclusively to the DSP cores.
429 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
430 This value denotes start offset of M2 memory
431 which is directly connected to the DSP core.
433 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
434 This value denotes start offset of M3 memory which is directly
435 connected to the DSP core.
437 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
438 This value denotes start offset of DSP CCSR space.
440 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
441 Single Source Clock is clocking mode present in some of FSL SoC's.
442 In this mode, a single differential clock is used to supply
443 clocks to the sysclock, ddrclock and usbclock.
445 CONFIG_SYS_CPC_REINIT_F
446 This CONFIG is defined when the CPC is configured as SRAM at the
447 time of U-boot entry and is required to be re-initialized.
450 Inidcates this SoC supports deep sleep feature. If deep sleep is
451 supported, core will start to execute uboot when wakes up.
453 - Generic CPU options:
454 CONFIG_SYS_GENERIC_GLOBAL_DATA
455 Defines global data is initialized in generic board board_init_f().
456 If this macro is defined, global data is created and cleared in
457 generic board board_init_f(). Without this macro, architecture/board
458 should initialize global data before calling board_init_f().
460 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
462 Defines the endianess of the CPU. Implementation of those
463 values is arch specific.
466 Freescale DDR driver in use. This type of DDR controller is
467 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
470 CONFIG_SYS_FSL_DDR_ADDR
471 Freescale DDR memory-mapped register base.
473 CONFIG_SYS_FSL_DDR_EMU
474 Specify emulator support for DDR. Some DDR features such as
475 deskew training are not available.
477 CONFIG_SYS_FSL_DDRC_GEN1
478 Freescale DDR1 controller.
480 CONFIG_SYS_FSL_DDRC_GEN2
481 Freescale DDR2 controller.
483 CONFIG_SYS_FSL_DDRC_GEN3
484 Freescale DDR3 controller.
486 CONFIG_SYS_FSL_DDRC_GEN4
487 Freescale DDR4 controller.
489 CONFIG_SYS_FSL_DDRC_ARM_GEN3
490 Freescale DDR3 controller for ARM-based SoCs.
493 Board config to use DDR1. It can be enabled for SoCs with
494 Freescale DDR1 or DDR2 controllers, depending on the board
498 Board config to use DDR2. It can be eanbeld for SoCs with
499 Freescale DDR2 or DDR3 controllers, depending on the board
503 Board config to use DDR3. It can be enabled for SoCs with
504 Freescale DDR3 or DDR3L controllers.
507 Board config to use DDR3L. It can be enabled for SoCs with
511 Board config to use DDR4. It can be enabled for SoCs with
514 CONFIG_SYS_FSL_IFC_BE
515 Defines the IFC controller register space as Big Endian
517 CONFIG_SYS_FSL_IFC_LE
518 Defines the IFC controller register space as Little Endian
520 CONFIG_SYS_FSL_PBL_PBI
521 It enables addition of RCW (Power on reset configuration) in built image.
522 Please refer doc/README.pblimage for more details
524 CONFIG_SYS_FSL_PBL_RCW
525 It adds PBI(pre-boot instructions) commands in u-boot build image.
526 PBI commands can be used to configure SoC before it starts the execution.
527 Please refer doc/README.pblimage for more details
530 It adds a target to create boot binary having SPL binary in PBI format
531 concatenated with u-boot binary.
533 CONFIG_SYS_FSL_DDR_BE
534 Defines the DDR controller register space as Big Endian
536 CONFIG_SYS_FSL_DDR_LE
537 Defines the DDR controller register space as Little Endian
539 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
540 Physical address from the view of DDR controllers. It is the
541 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
542 it could be different for ARM SoCs.
544 CONFIG_SYS_FSL_DDR_INTLV_256B
545 DDR controller interleaving on 256-byte. This is a special
546 interleaving mode, handled by Dickens for Freescale layerscape
549 - Intel Monahans options:
550 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
552 Defines the Monahans run mode to oscillator
553 ratio. Valid values are 8, 16, 24, 31. The core
554 frequency is this value multiplied by 13 MHz.
556 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
558 Defines the Monahans turbo mode to oscillator
559 ratio. Valid values are 1 (default if undefined) and
560 2. The core frequency as calculated above is multiplied
564 CONFIG_SYS_INIT_SP_OFFSET
566 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
567 pointer. This is needed for the temporary stack before
570 CONFIG_SYS_MIPS_CACHE_MODE
572 Cache operation mode for the MIPS CPU.
573 See also arch/mips/include/asm/mipsregs.h.
575 CONF_CM_CACHABLE_NO_WA
578 CONF_CM_CACHABLE_NONCOHERENT
582 CONF_CM_CACHABLE_ACCELERATED
584 CONFIG_SYS_XWAY_EBU_BOOTCFG
586 Special option for Lantiq XWAY SoCs for booting from NOR flash.
587 See also arch/mips/cpu/mips32/start.S.
589 CONFIG_XWAY_SWAP_BYTES
591 Enable compilation of tools/xway-swap-bytes needed for Lantiq
592 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
593 be swapped if a flash programmer is used.
596 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
598 Select high exception vectors of the ARM core, e.g., do not
599 clear the V bit of the c1 register of CP15.
601 CONFIG_SYS_THUMB_BUILD
603 Use this flag to build U-Boot using the Thumb instruction
604 set for ARM architectures. Thumb instruction set provides
605 better code density. For ARM architectures that support
606 Thumb2 this flag will result in Thumb2 code generated by
609 CONFIG_ARM_ERRATA_716044
610 CONFIG_ARM_ERRATA_742230
611 CONFIG_ARM_ERRATA_743622
612 CONFIG_ARM_ERRATA_751472
613 CONFIG_ARM_ERRATA_794072
614 CONFIG_ARM_ERRATA_761320
616 If set, the workarounds for these ARM errata are applied early
617 during U-Boot startup. Note that these options force the
618 workarounds to be applied; no CPU-type/version detection
619 exists, unlike the similar options in the Linux kernel. Do not
620 set these options unless they apply!
625 The frequency of the timer returned by get_timer().
626 get_timer() must operate in milliseconds and this CONFIG
627 option must be set to 1000.
629 - Linux Kernel Interface:
632 U-Boot stores all clock information in Hz
633 internally. For binary compatibility with older Linux
634 kernels (which expect the clocks passed in the
635 bd_info data to be in MHz) the environment variable
636 "clocks_in_mhz" can be defined so that U-Boot
637 converts clock data to MHZ before passing it to the
639 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
640 "clocks_in_mhz=1" is automatically included in the
643 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
645 When transferring memsize parameter to linux, some versions
646 expect it to be in bytes, others in MB.
647 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
651 New kernel versions are expecting firmware settings to be
652 passed using flattened device trees (based on open firmware
656 * New libfdt-based support
657 * Adds the "fdt" command
658 * The bootm command automatically updates the fdt
660 OF_CPU - The proper name of the cpus node (only required for
661 MPC512X and MPC5xxx based boards).
662 OF_SOC - The proper name of the soc node (only required for
663 MPC512X and MPC5xxx based boards).
664 OF_TBCLK - The timebase frequency.
665 OF_STDOUT_PATH - The path to the console device
667 boards with QUICC Engines require OF_QE to set UCC MAC
670 CONFIG_OF_BOARD_SETUP
672 Board code has addition modification that it wants to make
673 to the flat device tree before handing it off to the kernel
677 This define fills in the correct boot CPU in the boot
678 param header, the default value is zero if undefined.
682 U-Boot can detect if an IDE device is present or not.
683 If not, and this new config option is activated, U-Boot
684 removes the ATA node from the DTS before booting Linux,
685 so the Linux IDE driver does not probe the device and
686 crash. This is needed for buggy hardware (uc101) where
687 no pull down resistor is connected to the signal IDE5V_DD7.
689 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
691 This setting is mandatory for all boards that have only one
692 machine type and must be used to specify the machine type
693 number as it appears in the ARM machine registry
694 (see http://www.arm.linux.org.uk/developer/machines/).
695 Only boards that have multiple machine types supported
696 in a single configuration file and the machine type is
697 runtime discoverable, do not have to use this setting.
699 - vxWorks boot parameters:
701 bootvx constructs a valid bootline using the following
702 environments variables: bootfile, ipaddr, serverip, hostname.
703 It loads the vxWorks image pointed bootfile.
705 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
706 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
707 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
708 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
710 CONFIG_SYS_VXWORKS_ADD_PARAMS
712 Add it at the end of the bootline. E.g "u=username pw=secret"
714 Note: If a "bootargs" environment is defined, it will overwride
715 the defaults discussed just above.
717 - Cache Configuration:
718 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
719 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
720 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
722 - Cache Configuration for ARM:
723 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
725 CONFIG_SYS_PL310_BASE - Physical base address of PL310
726 controller register space
731 Define this if you want support for Amba PrimeCell PL010 UARTs.
735 Define this if you want support for Amba PrimeCell PL011 UARTs.
739 If you have Amba PrimeCell PL011 UARTs, set this variable to
740 the clock speed of the UARTs.
744 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
745 define this to a list of base addresses for each (supported)
746 port. See e.g. include/configs/versatile.h
748 CONFIG_PL011_SERIAL_RLCR
750 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
751 have separate receive and transmit line control registers. Set
752 this variable to initialize the extra register.
754 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
756 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
757 boot loader that has already initialized the UART. Define this
758 variable to flush the UART at init time.
760 CONFIG_SERIAL_HW_FLOW_CONTROL
762 Define this variable to enable hw flow control in serial driver.
763 Current user of this option is drivers/serial/nsl16550.c driver
766 Depending on board, define exactly one serial port
767 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
768 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
769 console by defining CONFIG_8xx_CONS_NONE
771 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
772 port routines must be defined elsewhere
773 (i.e. serial_init(), serial_getc(), ...)
776 Enables console device for a color framebuffer. Needs following
777 defines (cf. smiLynxEM, i8042)
778 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
780 VIDEO_HW_RECTFILL graphic chip supports
783 VIDEO_HW_BITBLT graphic chip supports
784 bit-blit (cf. smiLynxEM)
785 VIDEO_VISIBLE_COLS visible pixel columns
787 VIDEO_VISIBLE_ROWS visible pixel rows
788 VIDEO_PIXEL_SIZE bytes per pixel
789 VIDEO_DATA_FORMAT graphic data format
790 (0-5, cf. cfb_console.c)
791 VIDEO_FB_ADRS framebuffer address
792 VIDEO_KBD_INIT_FCT keyboard int fct
793 (i.e. i8042_kbd_init())
794 VIDEO_TSTC_FCT test char fct
796 VIDEO_GETC_FCT get char fct
798 CONFIG_CONSOLE_CURSOR cursor drawing on/off
799 (requires blink timer
801 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
802 CONFIG_CONSOLE_TIME display time/date info in
804 (requires CONFIG_CMD_DATE)
805 CONFIG_VIDEO_LOGO display Linux logo in
807 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
808 linux_logo.h for logo.
809 Requires CONFIG_VIDEO_LOGO
810 CONFIG_CONSOLE_EXTRA_INFO
811 additional board info beside
814 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
815 a limited number of ANSI escape sequences (cursor control,
816 erase functions and limited graphics rendition control).
818 When CONFIG_CFB_CONSOLE is defined, video console is
819 default i/o. Serial console can be forced with
820 environment 'console=serial'.
822 When CONFIG_SILENT_CONSOLE is defined, all console
823 messages (by U-Boot and Linux!) can be silenced with
824 the "silent" environment variable. See
825 doc/README.silent for more information.
827 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
829 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
833 CONFIG_BAUDRATE - in bps
834 Select one of the baudrates listed in
835 CONFIG_SYS_BAUDRATE_TABLE, see below.
836 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
838 - Console Rx buffer length
839 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
840 the maximum receive buffer length for the SMC.
841 This option is actual only for 82xx and 8xx possible.
842 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
843 must be defined, to setup the maximum idle timeout for
846 - Pre-Console Buffer:
847 Prior to the console being initialised (i.e. serial UART
848 initialised etc) all console output is silently discarded.
849 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
850 buffer any console messages prior to the console being
851 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
852 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
853 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
854 bytes are output before the console is initialised, the
855 earlier bytes are discarded.
857 'Sane' compilers will generate smaller code if
858 CONFIG_PRE_CON_BUF_SZ is a power of 2
860 - Safe printf() functions
861 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
862 the printf() functions. These are defined in
863 include/vsprintf.h and include snprintf(), vsnprintf() and
864 so on. Code size increase is approximately 300-500 bytes.
865 If this option is not given then these functions will
866 silently discard their buffer size argument - this means
867 you are not getting any overflow checking in this case.
869 - Boot Delay: CONFIG_BOOTDELAY - in seconds
870 Delay before automatically booting the default image;
871 set to -1 to disable autoboot.
872 set to -2 to autoboot with no delay and not check for abort
873 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
875 See doc/README.autoboot for these options that
876 work with CONFIG_BOOTDELAY. None are required.
877 CONFIG_BOOT_RETRY_TIME
878 CONFIG_BOOT_RETRY_MIN
879 CONFIG_AUTOBOOT_KEYED
880 CONFIG_AUTOBOOT_PROMPT
881 CONFIG_AUTOBOOT_DELAY_STR
882 CONFIG_AUTOBOOT_STOP_STR
883 CONFIG_AUTOBOOT_DELAY_STR2
884 CONFIG_AUTOBOOT_STOP_STR2
885 CONFIG_ZERO_BOOTDELAY_CHECK
886 CONFIG_RESET_TO_RETRY
890 Only needed when CONFIG_BOOTDELAY is enabled;
891 define a command string that is automatically executed
892 when no character is read on the console interface
893 within "Boot Delay" after reset.
896 This can be used to pass arguments to the bootm
897 command. The value of CONFIG_BOOTARGS goes into the
898 environment value "bootargs".
900 CONFIG_RAMBOOT and CONFIG_NFSBOOT
901 The value of these goes into the environment as
902 "ramboot" and "nfsboot" respectively, and can be used
903 as a convenience, when switching between booting from
907 CONFIG_BOOTCOUNT_LIMIT
908 Implements a mechanism for detecting a repeating reboot
910 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
913 If no softreset save registers are found on the hardware
914 "bootcount" is stored in the environment. To prevent a
915 saveenv on all reboots, the environment variable
916 "upgrade_available" is used. If "upgrade_available" is
917 0, "bootcount" is always 0, if "upgrade_available" is
918 1 "bootcount" is incremented in the environment.
919 So the Userspace Applikation must set the "upgrade_available"
920 and "bootcount" variable to 0, if a boot was successfully.
925 When this option is #defined, the existence of the
926 environment variable "preboot" will be checked
927 immediately before starting the CONFIG_BOOTDELAY
928 countdown and/or running the auto-boot command resp.
929 entering interactive mode.
931 This feature is especially useful when "preboot" is
932 automatically generated or modified. For an example
933 see the LWMON board specific code: here "preboot" is
934 modified when the user holds down a certain
935 combination of keys on the (special) keyboard when
938 - Serial Download Echo Mode:
940 If defined to 1, all characters received during a
941 serial download (using the "loads" command) are
942 echoed back. This might be needed by some terminal
943 emulations (like "cu"), but may as well just take
944 time on others. This setting #define's the initial
945 value of the "loads_echo" environment variable.
947 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
949 Select one of the baudrates listed in
950 CONFIG_SYS_BAUDRATE_TABLE, see below.
953 Monitor commands can be included or excluded
954 from the build by using the #include files
955 <config_cmd_all.h> and #undef'ing unwanted
956 commands, or using <config_cmd_default.h>
957 and augmenting with additional #define's
960 The default command configuration includes all commands
961 except those marked below with a "*".
963 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
964 CONFIG_CMD_ASKENV * ask for env variable
965 CONFIG_CMD_BDI bdinfo
966 CONFIG_CMD_BEDBUG * Include BedBug Debugger
967 CONFIG_CMD_BMP * BMP support
968 CONFIG_CMD_BSP * Board specific commands
969 CONFIG_CMD_BOOTD bootd
970 CONFIG_CMD_CACHE * icache, dcache
971 CONFIG_CMD_CLK * clock command support
972 CONFIG_CMD_CONSOLE coninfo
973 CONFIG_CMD_CRC32 * crc32
974 CONFIG_CMD_DATE * support for RTC, date/time...
975 CONFIG_CMD_DHCP * DHCP support
976 CONFIG_CMD_DIAG * Diagnostics
977 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
978 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
979 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
980 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
981 CONFIG_CMD_DTT * Digital Therm and Thermostat
982 CONFIG_CMD_ECHO echo arguments
983 CONFIG_CMD_EDITENV edit env variable
984 CONFIG_CMD_EEPROM * EEPROM read/write support
985 CONFIG_CMD_ELF * bootelf, bootvx
986 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
987 CONFIG_CMD_ENV_FLAGS * display details about env flags
988 CONFIG_CMD_ENV_EXISTS * check existence of env variable
989 CONFIG_CMD_EXPORTENV * export the environment
990 CONFIG_CMD_EXT2 * ext2 command support
991 CONFIG_CMD_EXT4 * ext4 command support
992 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
993 that work for multiple fs types
994 CONFIG_CMD_SAVEENV saveenv
995 CONFIG_CMD_FDC * Floppy Disk Support
996 CONFIG_CMD_FAT * FAT command support
997 CONFIG_CMD_FLASH flinfo, erase, protect
998 CONFIG_CMD_FPGA FPGA device initialization support
999 CONFIG_CMD_FUSE * Device fuse support
1000 CONFIG_CMD_GETTIME * Get time since boot
1001 CONFIG_CMD_GO * the 'go' command (exec code)
1002 CONFIG_CMD_GREPENV * search environment
1003 CONFIG_CMD_HASH * calculate hash / digest
1004 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1005 CONFIG_CMD_I2C * I2C serial bus support
1006 CONFIG_CMD_IDE * IDE harddisk support
1007 CONFIG_CMD_IMI iminfo
1008 CONFIG_CMD_IMLS List all images found in NOR flash
1009 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1010 CONFIG_CMD_IMMAP * IMMR dump support
1011 CONFIG_CMD_IMPORTENV * import an environment
1012 CONFIG_CMD_INI * import data from an ini file into the env
1013 CONFIG_CMD_IRQ * irqinfo
1014 CONFIG_CMD_ITEST Integer/string test of 2 values
1015 CONFIG_CMD_JFFS2 * JFFS2 Support
1016 CONFIG_CMD_KGDB * kgdb
1017 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1018 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1020 CONFIG_CMD_LOADB loadb
1021 CONFIG_CMD_LOADS loads
1022 CONFIG_CMD_MD5SUM * print md5 message digest
1023 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1024 CONFIG_CMD_MEMINFO * Display detailed memory information
1025 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1027 CONFIG_CMD_MEMTEST * mtest
1028 CONFIG_CMD_MISC Misc functions like sleep etc
1029 CONFIG_CMD_MMC * MMC memory mapped support
1030 CONFIG_CMD_MII * MII utility commands
1031 CONFIG_CMD_MTDPARTS * MTD partition support
1032 CONFIG_CMD_NAND * NAND support
1033 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1034 CONFIG_CMD_NFS NFS support
1035 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1036 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1037 CONFIG_CMD_PCI * pciinfo
1038 CONFIG_CMD_PCMCIA * PCMCIA support
1039 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1041 CONFIG_CMD_PORTIO * Port I/O
1042 CONFIG_CMD_READ * Read raw data from partition
1043 CONFIG_CMD_REGINFO * Register dump
1044 CONFIG_CMD_RUN run command in env variable
1045 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1046 CONFIG_CMD_SAVES * save S record dump
1047 CONFIG_CMD_SCSI * SCSI Support
1048 CONFIG_CMD_SDRAM * print SDRAM configuration information
1049 (requires CONFIG_CMD_I2C)
1050 CONFIG_CMD_SETGETDCR Support for DCR Register access
1052 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1053 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1054 (requires CONFIG_CMD_MEMORY)
1055 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1056 CONFIG_CMD_SOURCE "source" command Support
1057 CONFIG_CMD_SPI * SPI serial bus support
1058 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1059 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1060 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1061 CONFIG_CMD_TIMER * access to the system tick timer
1062 CONFIG_CMD_USB * USB support
1063 CONFIG_CMD_CDP * Cisco Discover Protocol support
1064 CONFIG_CMD_MFSL * Microblaze FSL support
1065 CONFIG_CMD_XIMG Load part of Multi Image
1066 CONFIG_CMD_UUID * Generate random UUID or GUID string
1068 EXAMPLE: If you want all functions except of network
1069 support you can write:
1071 #include "config_cmd_all.h"
1072 #undef CONFIG_CMD_NET
1075 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1077 Note: Don't enable the "icache" and "dcache" commands
1078 (configuration option CONFIG_CMD_CACHE) unless you know
1079 what you (and your U-Boot users) are doing. Data
1080 cache cannot be enabled on systems like the 8xx or
1081 8260 (where accesses to the IMMR region must be
1082 uncached), and it cannot be disabled on all other
1083 systems where we (mis-) use the data cache to hold an
1084 initial stack and some data.
1087 XXX - this list needs to get updated!
1089 - Regular expression support:
1091 If this variable is defined, U-Boot is linked against
1092 the SLRE (Super Light Regular Expression) library,
1093 which adds regex support to some commands, as for
1094 example "env grep" and "setexpr".
1098 If this variable is defined, U-Boot will use a device tree
1099 to configure its devices, instead of relying on statically
1100 compiled #defines in the board file. This option is
1101 experimental and only available on a few boards. The device
1102 tree is available in the global data as gd->fdt_blob.
1104 U-Boot needs to get its device tree from somewhere. This can
1105 be done using one of the two options below:
1108 If this variable is defined, U-Boot will embed a device tree
1109 binary in its image. This device tree file should be in the
1110 board directory and called <soc>-<board>.dts. The binary file
1111 is then picked up in board_init_f() and made available through
1112 the global data structure as gd->blob.
1115 If this variable is defined, U-Boot will build a device tree
1116 binary. It will be called u-boot.dtb. Architecture-specific
1117 code will locate it at run-time. Generally this works by:
1119 cat u-boot.bin u-boot.dtb >image.bin
1121 and in fact, U-Boot does this for you, creating a file called
1122 u-boot-dtb.bin which is useful in the common case. You can
1123 still use the individual files if you need something more
1128 If this variable is defined, it enables watchdog
1129 support for the SoC. There must be support in the SoC
1130 specific code for a watchdog. For the 8xx and 8260
1131 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1132 register. When supported for a specific SoC is
1133 available, then no further board specific code should
1134 be needed to use it.
1137 When using a watchdog circuitry external to the used
1138 SoC, then define this variable and provide board
1139 specific code for the "hw_watchdog_reset" function.
1142 CONFIG_VERSION_VARIABLE
1143 If this variable is defined, an environment variable
1144 named "ver" is created by U-Boot showing the U-Boot
1145 version as printed by the "version" command.
1146 Any change to this variable will be reverted at the
1151 When CONFIG_CMD_DATE is selected, the type of the RTC
1152 has to be selected, too. Define exactly one of the
1155 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1156 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1157 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1158 CONFIG_RTC_MC146818 - use MC146818 RTC
1159 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1160 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1161 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1162 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1163 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1164 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1165 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1166 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1169 Note that if the RTC uses I2C, then the I2C interface
1170 must also be configured. See I2C Support, below.
1173 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1175 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1176 chip-ngpio pairs that tell the PCA953X driver the number of
1177 pins supported by a particular chip.
1179 Note that if the GPIO device uses I2C, then the I2C interface
1180 must also be configured. See I2C Support, below.
1182 - Timestamp Support:
1184 When CONFIG_TIMESTAMP is selected, the timestamp
1185 (date and time) of an image is printed by image
1186 commands like bootm or iminfo. This option is
1187 automatically enabled when you select CONFIG_CMD_DATE .
1189 - Partition Labels (disklabels) Supported:
1190 Zero or more of the following:
1191 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1192 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1193 Intel architecture, USB sticks, etc.
1194 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1195 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1196 bootloader. Note 2TB partition limit; see
1198 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1200 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1201 CONFIG_CMD_SCSI) you must configure support for at
1202 least one non-MTD partition type as well.
1205 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1206 board configurations files but used nowhere!
1208 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1209 be performed by calling the function
1210 ide_set_reset(int reset)
1211 which has to be defined in a board specific file
1216 Set this to enable ATAPI support.
1221 Set this to enable support for disks larger than 137GB
1222 Also look at CONFIG_SYS_64BIT_LBA.
1223 Whithout these , LBA48 support uses 32bit variables and will 'only'
1224 support disks up to 2.1TB.
1226 CONFIG_SYS_64BIT_LBA:
1227 When enabled, makes the IDE subsystem use 64bit sector addresses.
1231 At the moment only there is only support for the
1232 SYM53C8XX SCSI controller; define
1233 CONFIG_SCSI_SYM53C8XX to enable it.
1235 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1236 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1237 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1238 maximum numbers of LUNs, SCSI ID's and target
1240 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1242 The environment variable 'scsidevs' is set to the number of
1243 SCSI devices found during the last scan.
1245 - NETWORK Support (PCI):
1247 Support for Intel 8254x/8257x gigabit chips.
1250 Utility code for direct access to the SPI bus on Intel 8257x.
1251 This does not do anything useful unless you set at least one
1252 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1254 CONFIG_E1000_SPI_GENERIC
1255 Allow generic access to the SPI bus on the Intel 8257x, for
1256 example with the "sspi" command.
1259 Management command for E1000 devices. When used on devices
1260 with SPI support you can reprogram the EEPROM from U-Boot.
1262 CONFIG_E1000_FALLBACK_MAC
1263 default MAC for empty EEPROM after production.
1266 Support for Intel 82557/82559/82559ER chips.
1267 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1268 write routine for first time initialisation.
1271 Support for Digital 2114x chips.
1272 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1273 modem chip initialisation (KS8761/QS6611).
1276 Support for National dp83815 chips.
1279 Support for National dp8382[01] gigabit chips.
1281 - NETWORK Support (other):
1283 CONFIG_DRIVER_AT91EMAC
1284 Support for AT91RM9200 EMAC.
1287 Define this to use reduced MII inteface
1289 CONFIG_DRIVER_AT91EMAC_QUIET
1290 If this defined, the driver is quiet.
1291 The driver doen't show link status messages.
1293 CONFIG_CALXEDA_XGMAC
1294 Support for the Calxeda XGMAC device
1297 Support for SMSC's LAN91C96 chips.
1299 CONFIG_LAN91C96_BASE
1300 Define this to hold the physical address
1301 of the LAN91C96's I/O space
1303 CONFIG_LAN91C96_USE_32_BIT
1304 Define this to enable 32 bit addressing
1307 Support for SMSC's LAN91C111 chip
1309 CONFIG_SMC91111_BASE
1310 Define this to hold the physical address
1311 of the device (I/O space)
1313 CONFIG_SMC_USE_32_BIT
1314 Define this if data bus is 32 bits
1316 CONFIG_SMC_USE_IOFUNCS
1317 Define this to use i/o functions instead of macros
1318 (some hardware wont work with macros)
1320 CONFIG_DRIVER_TI_EMAC
1321 Support for davinci emac
1323 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1324 Define this if you have more then 3 PHYs.
1327 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1329 CONFIG_FTGMAC100_EGIGA
1330 Define this to use GE link update with gigabit PHY.
1331 Define this if FTGMAC100 is connected to gigabit PHY.
1332 If your system has 10/100 PHY only, it might not occur
1333 wrong behavior. Because PHY usually return timeout or
1334 useless data when polling gigabit status and gigabit
1335 control registers. This behavior won't affect the
1336 correctnessof 10/100 link speed update.
1339 Support for SMSC's LAN911x and LAN921x chips
1342 Define this to hold the physical address
1343 of the device (I/O space)
1345 CONFIG_SMC911X_32_BIT
1346 Define this if data bus is 32 bits
1348 CONFIG_SMC911X_16_BIT
1349 Define this if data bus is 16 bits. If your processor
1350 automatically converts one 32 bit word to two 16 bit
1351 words you may also try CONFIG_SMC911X_32_BIT.
1354 Support for Renesas on-chip Ethernet controller
1356 CONFIG_SH_ETHER_USE_PORT
1357 Define the number of ports to be used
1359 CONFIG_SH_ETHER_PHY_ADDR
1360 Define the ETH PHY's address
1362 CONFIG_SH_ETHER_CACHE_WRITEBACK
1363 If this option is set, the driver enables cache flush.
1367 Support TPM devices.
1370 Support for i2c bus TPM devices. Only one device
1371 per system is supported at this time.
1373 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1374 Define the the i2c bus number for the TPM device
1376 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1377 Define the TPM's address on the i2c bus
1379 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1380 Define the burst count bytes upper limit
1382 CONFIG_TPM_ATMEL_TWI
1383 Support for Atmel TWI TPM device. Requires I2C support.
1386 Support for generic parallel port TPM devices. Only one device
1387 per system is supported at this time.
1389 CONFIG_TPM_TIS_BASE_ADDRESS
1390 Base address where the generic TPM device is mapped
1391 to. Contemporary x86 systems usually map it at
1395 Add tpm monitor functions.
1396 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1397 provides monitor access to authorized functions.
1400 Define this to enable the TPM support library which provides
1401 functional interfaces to some TPM commands.
1402 Requires support for a TPM device.
1404 CONFIG_TPM_AUTH_SESSIONS
1405 Define this to enable authorized functions in the TPM library.
1406 Requires CONFIG_TPM and CONFIG_SHA1.
1409 At the moment only the UHCI host controller is
1410 supported (PIP405, MIP405, MPC5200); define
1411 CONFIG_USB_UHCI to enable it.
1412 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1413 and define CONFIG_USB_STORAGE to enable the USB
1416 Supported are USB Keyboards and USB Floppy drives
1418 MPC5200 USB requires additional defines:
1420 for 528 MHz Clock: 0x0001bbbb
1424 for differential drivers: 0x00001000
1425 for single ended drivers: 0x00005000
1426 for differential drivers on PSC3: 0x00000100
1427 for single ended drivers on PSC3: 0x00004100
1428 CONFIG_SYS_USB_EVENT_POLL
1429 May be defined to allow interrupt polling
1430 instead of using asynchronous interrupts
1432 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1433 txfilltuning field in the EHCI controller on reset.
1435 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1436 interval for usb hub power-on delay.(minimum 100msec)
1439 Define the below if you wish to use the USB console.
1440 Once firmware is rebuilt from a serial console issue the
1441 command "setenv stdin usbtty; setenv stdout usbtty" and
1442 attach your USB cable. The Unix command "dmesg" should print
1443 it has found a new device. The environment variable usbtty
1444 can be set to gserial or cdc_acm to enable your device to
1445 appear to a USB host as a Linux gserial device or a
1446 Common Device Class Abstract Control Model serial device.
1447 If you select usbtty = gserial you should be able to enumerate
1449 # modprobe usbserial vendor=0xVendorID product=0xProductID
1450 else if using cdc_acm, simply setting the environment
1451 variable usbtty to be cdc_acm should suffice. The following
1452 might be defined in YourBoardName.h
1455 Define this to build a UDC device
1458 Define this to have a tty type of device available to
1459 talk to the UDC device
1462 Define this to enable the high speed support for usb
1463 device and usbtty. If this feature is enabled, a routine
1464 int is_usbd_high_speed(void)
1465 also needs to be defined by the driver to dynamically poll
1466 whether the enumeration has succeded at high speed or full
1469 CONFIG_SYS_CONSOLE_IS_IN_ENV
1470 Define this if you want stdin, stdout &/or stderr to
1474 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1475 Derive USB clock from external clock "blah"
1476 - CONFIG_SYS_USB_EXTC_CLK 0x02
1478 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1479 Derive USB clock from brgclk
1480 - CONFIG_SYS_USB_BRG_CLK 0x04
1482 If you have a USB-IF assigned VendorID then you may wish to
1483 define your own vendor specific values either in BoardName.h
1484 or directly in usbd_vendor_info.h. If you don't define
1485 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1486 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1487 should pretend to be a Linux device to it's target host.
1489 CONFIG_USBD_MANUFACTURER
1490 Define this string as the name of your company for
1491 - CONFIG_USBD_MANUFACTURER "my company"
1493 CONFIG_USBD_PRODUCT_NAME
1494 Define this string as the name of your product
1495 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1497 CONFIG_USBD_VENDORID
1498 Define this as your assigned Vendor ID from the USB
1499 Implementors Forum. This *must* be a genuine Vendor ID
1500 to avoid polluting the USB namespace.
1501 - CONFIG_USBD_VENDORID 0xFFFF
1503 CONFIG_USBD_PRODUCTID
1504 Define this as the unique Product ID
1506 - CONFIG_USBD_PRODUCTID 0xFFFF
1508 - ULPI Layer Support:
1509 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1510 the generic ULPI layer. The generic layer accesses the ULPI PHY
1511 via the platform viewport, so you need both the genric layer and
1512 the viewport enabled. Currently only Chipidea/ARC based
1513 viewport is supported.
1514 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1515 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1516 If your ULPI phy needs a different reference clock than the
1517 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1518 the appropriate value in Hz.
1521 The MMC controller on the Intel PXA is supported. To
1522 enable this define CONFIG_MMC. The MMC can be
1523 accessed from the boot prompt by mapping the device
1524 to physical memory similar to flash. Command line is
1525 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1526 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1529 Support for Renesas on-chip MMCIF controller
1531 CONFIG_SH_MMCIF_ADDR
1532 Define the base address of MMCIF registers
1535 Define the clock frequency for MMCIF
1537 - USB Device Firmware Update (DFU) class support:
1539 This enables the USB portion of the DFU USB class
1542 This enables the command "dfu" which is used to have
1543 U-Boot create a DFU class device via USB. This command
1544 requires that the "dfu_alt_info" environment variable be
1545 set and define the alt settings to expose to the host.
1548 This enables support for exposing (e)MMC devices via DFU.
1551 This enables support for exposing NAND devices via DFU.
1554 This enables support for exposing RAM via DFU.
1555 Note: DFU spec refer to non-volatile memory usage, but
1556 allow usages beyond the scope of spec - here RAM usage,
1557 one that would help mostly the developer.
1559 CONFIG_SYS_DFU_DATA_BUF_SIZE
1560 Dfu transfer uses a buffer before writing data to the
1561 raw storage device. Make the size (in bytes) of this buffer
1562 configurable. The size of this buffer is also configurable
1563 through the "dfu_bufsiz" environment variable.
1565 CONFIG_SYS_DFU_MAX_FILE_SIZE
1566 When updating files rather than the raw storage device,
1567 we use a static buffer to copy the file into and then write
1568 the buffer once we've been given the whole file. Define
1569 this to the maximum filesize (in bytes) for the buffer.
1570 Default is 4 MiB if undefined.
1572 DFU_DEFAULT_POLL_TIMEOUT
1573 Poll timeout [ms], is the timeout a device can send to the
1574 host. The host must wait for this timeout before sending
1575 a subsequent DFU_GET_STATUS request to the device.
1577 DFU_MANIFEST_POLL_TIMEOUT
1578 Poll timeout [ms], which the device sends to the host when
1579 entering dfuMANIFEST state. Host waits this timeout, before
1580 sending again an USB request to the device.
1582 - Journaling Flash filesystem support:
1583 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1584 CONFIG_JFFS2_NAND_DEV
1585 Define these for a default partition on a NAND device
1587 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1588 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1589 Define these for a default partition on a NOR device
1591 CONFIG_SYS_JFFS_CUSTOM_PART
1592 Define this to create an own partition. You have to provide a
1593 function struct part_info* jffs2_part_info(int part_num)
1595 If you define only one JFFS2 partition you may also want to
1596 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1597 to disable the command chpart. This is the default when you
1598 have not defined a custom partition
1600 - FAT(File Allocation Table) filesystem write function support:
1603 Define this to enable support for saving memory data as a
1604 file in FAT formatted partition.
1606 This will also enable the command "fatwrite" enabling the
1607 user to write files to FAT.
1609 CBFS (Coreboot Filesystem) support
1612 Define this to enable support for reading from a Coreboot
1613 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1619 Define this to enable standard (PC-Style) keyboard
1623 Standard PC keyboard driver with US (is default) and
1624 GERMAN key layout (switch via environment 'keymap=de') support.
1625 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1626 for cfb_console. Supports cursor blinking.
1629 Enables a Chrome OS keyboard using the CROS_EC interface.
1630 This uses CROS_EC to communicate with a second microcontroller
1631 which provides key scans on request.
1636 Define this to enable video support (for output to
1639 CONFIG_VIDEO_CT69000
1641 Enable Chips & Technologies 69000 Video chip
1643 CONFIG_VIDEO_SMI_LYNXEM
1644 Enable Silicon Motion SMI 712/710/810 Video chip. The
1645 video output is selected via environment 'videoout'
1646 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1649 For the CT69000 and SMI_LYNXEM drivers, videomode is
1650 selected via environment 'videomode'. Two different ways
1652 - "videomode=num" 'num' is a standard LiLo mode numbers.
1653 Following standard modes are supported (* is default):
1655 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1656 -------------+---------------------------------------------
1657 8 bits | 0x301* 0x303 0x305 0x161 0x307
1658 15 bits | 0x310 0x313 0x316 0x162 0x319
1659 16 bits | 0x311 0x314 0x317 0x163 0x31A
1660 24 bits | 0x312 0x315 0x318 ? 0x31B
1661 -------------+---------------------------------------------
1662 (i.e. setenv videomode 317; saveenv; reset;)
1664 - "videomode=bootargs" all the video parameters are parsed
1665 from the bootargs. (See drivers/video/videomodes.c)
1668 CONFIG_VIDEO_SED13806
1669 Enable Epson SED13806 driver. This driver supports 8bpp
1670 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1671 or CONFIG_VIDEO_SED13806_16BPP
1674 Enable the Freescale DIU video driver. Reference boards for
1675 SOCs that have a DIU should define this macro to enable DIU
1676 support, and should also define these other macros:
1682 CONFIG_VIDEO_SW_CURSOR
1683 CONFIG_VGA_AS_SINGLE_DEVICE
1685 CONFIG_VIDEO_BMP_LOGO
1687 The DIU driver will look for the 'video-mode' environment
1688 variable, and if defined, enable the DIU as a console during
1689 boot. See the documentation file README.video for a
1690 description of this variable.
1694 Enable the VGA video / BIOS for x86. The alternative if you
1695 are using coreboot is to use the coreboot frame buffer
1702 Define this to enable a custom keyboard support.
1703 This simply calls drv_keyboard_init() which must be
1704 defined in your board-specific files.
1705 The only board using this so far is RBC823.
1707 - LCD Support: CONFIG_LCD
1709 Define this to enable LCD support (for output to LCD
1710 display); also select one of the supported displays
1711 by defining one of these:
1715 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1717 CONFIG_NEC_NL6448AC33:
1719 NEC NL6448AC33-18. Active, color, single scan.
1721 CONFIG_NEC_NL6448BC20
1723 NEC NL6448BC20-08. 6.5", 640x480.
1724 Active, color, single scan.
1726 CONFIG_NEC_NL6448BC33_54
1728 NEC NL6448BC33-54. 10.4", 640x480.
1729 Active, color, single scan.
1733 Sharp 320x240. Active, color, single scan.
1734 It isn't 16x9, and I am not sure what it is.
1736 CONFIG_SHARP_LQ64D341
1738 Sharp LQ64D341 display, 640x480.
1739 Active, color, single scan.
1743 HLD1045 display, 640x480.
1744 Active, color, single scan.
1748 Optrex CBL50840-2 NF-FW 99 22 M5
1750 Hitachi LMG6912RPFC-00T
1754 320x240. Black & white.
1756 Normally display is black on white background; define
1757 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1759 CONFIG_LCD_ALIGNMENT
1761 Normally the LCD is page-aligned (tyically 4KB). If this is
1762 defined then the LCD will be aligned to this value instead.
1763 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1764 here, since it is cheaper to change data cache settings on
1765 a per-section basis.
1767 CONFIG_CONSOLE_SCROLL_LINES
1769 When the console need to be scrolled, this is the number of
1770 lines to scroll by. It defaults to 1. Increasing this makes
1771 the console jump but can help speed up operation when scrolling
1776 Support drawing of RLE8-compressed bitmaps on the LCD.
1780 Enables an 'i2c edid' command which can read EDID
1781 information over I2C from an attached LCD display.
1783 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1785 If this option is set, the environment is checked for
1786 a variable "splashimage". If found, the usual display
1787 of logo, copyright and system information on the LCD
1788 is suppressed and the BMP image at the address
1789 specified in "splashimage" is loaded instead. The
1790 console is redirected to the "nulldev", too. This
1791 allows for a "silent" boot where a splash screen is
1792 loaded very quickly after power-on.
1794 CONFIG_SPLASHIMAGE_GUARD
1796 If this option is set, then U-Boot will prevent the environment
1797 variable "splashimage" from being set to a problematic address
1798 (see README.displaying-bmps).
1799 This option is useful for targets where, due to alignment
1800 restrictions, an improperly aligned BMP image will cause a data
1801 abort. If you think you will not have problems with unaligned
1802 accesses (for example because your toolchain prevents them)
1803 there is no need to set this option.
1805 CONFIG_SPLASH_SCREEN_ALIGN
1807 If this option is set the splash image can be freely positioned
1808 on the screen. Environment variable "splashpos" specifies the
1809 position as "x,y". If a positive number is given it is used as
1810 number of pixel from left/top. If a negative number is given it
1811 is used as number of pixel from right/bottom. You can also
1812 specify 'm' for centering the image.
1815 setenv splashpos m,m
1816 => image at center of screen
1818 setenv splashpos 30,20
1819 => image at x = 30 and y = 20
1821 setenv splashpos -10,m
1822 => vertically centered image
1823 at x = dspWidth - bmpWidth - 9
1825 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1827 If this option is set, additionally to standard BMP
1828 images, gzipped BMP images can be displayed via the
1829 splashscreen support or the bmp command.
1831 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1833 If this option is set, 8-bit RLE compressed BMP images
1834 can be displayed via the splashscreen support or the
1837 - Do compresssing for memory range:
1840 If this option is set, it would use zlib deflate method
1841 to compress the specified memory at its best effort.
1843 - Compression support:
1846 Enabled by default to support gzip compressed images.
1850 If this option is set, support for bzip2 compressed
1851 images is included. If not, only uncompressed and gzip
1852 compressed images are supported.
1854 NOTE: the bzip2 algorithm requires a lot of RAM, so
1855 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1860 If this option is set, support for lzma compressed
1863 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1864 requires an amount of dynamic memory that is given by the
1867 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1869 Where lc and lp stand for, respectively, Literal context bits
1870 and Literal pos bits.
1872 This value is upper-bounded by 14MB in the worst case. Anyway,
1873 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1874 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1875 a very small buffer.
1877 Use the lzmainfo tool to determinate the lc and lp values and
1878 then calculate the amount of needed dynamic memory (ensuring
1879 the appropriate CONFIG_SYS_MALLOC_LEN value).
1883 If this option is set, support for LZO compressed images
1889 The address of PHY on MII bus.
1891 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1893 The clock frequency of the MII bus
1897 If this option is set, support for speed/duplex
1898 detection of gigabit PHY is included.
1900 CONFIG_PHY_RESET_DELAY
1902 Some PHY like Intel LXT971A need extra delay after
1903 reset before any MII register access is possible.
1904 For such PHY, set this option to the usec delay
1905 required. (minimum 300usec for LXT971A)
1907 CONFIG_PHY_CMD_DELAY (ppc4xx)
1909 Some PHY like Intel LXT971A need extra delay after
1910 command issued before MII status register can be read
1920 Define a default value for Ethernet address to use
1921 for the respective Ethernet interface, in case this
1922 is not determined automatically.
1927 Define a default value for the IP address to use for
1928 the default Ethernet interface, in case this is not
1929 determined through e.g. bootp.
1930 (Environment variable "ipaddr")
1932 - Server IP address:
1935 Defines a default value for the IP address of a TFTP
1936 server to contact when using the "tftboot" command.
1937 (Environment variable "serverip")
1939 CONFIG_KEEP_SERVERADDR
1941 Keeps the server's MAC address, in the env 'serveraddr'
1942 for passing to bootargs (like Linux's netconsole option)
1944 - Gateway IP address:
1947 Defines a default value for the IP address of the
1948 default router where packets to other networks are
1950 (Environment variable "gatewayip")
1955 Defines a default value for the subnet mask (or
1956 routing prefix) which is used to determine if an IP
1957 address belongs to the local subnet or needs to be
1958 forwarded through a router.
1959 (Environment variable "netmask")
1961 - Multicast TFTP Mode:
1964 Defines whether you want to support multicast TFTP as per
1965 rfc-2090; for example to work with atftp. Lets lots of targets
1966 tftp down the same boot image concurrently. Note: the Ethernet
1967 driver in use must provide a function: mcast() to join/leave a
1970 - BOOTP Recovery Mode:
1971 CONFIG_BOOTP_RANDOM_DELAY
1973 If you have many targets in a network that try to
1974 boot using BOOTP, you may want to avoid that all
1975 systems send out BOOTP requests at precisely the same
1976 moment (which would happen for instance at recovery
1977 from a power failure, when all systems will try to
1978 boot, thus flooding the BOOTP server. Defining
1979 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1980 inserted before sending out BOOTP requests. The
1981 following delays are inserted then:
1983 1st BOOTP request: delay 0 ... 1 sec
1984 2nd BOOTP request: delay 0 ... 2 sec
1985 3rd BOOTP request: delay 0 ... 4 sec
1987 BOOTP requests: delay 0 ... 8 sec
1989 - DHCP Advanced Options:
1990 You can fine tune the DHCP functionality by defining
1991 CONFIG_BOOTP_* symbols:
1993 CONFIG_BOOTP_SUBNETMASK
1994 CONFIG_BOOTP_GATEWAY
1995 CONFIG_BOOTP_HOSTNAME
1996 CONFIG_BOOTP_NISDOMAIN
1997 CONFIG_BOOTP_BOOTPATH
1998 CONFIG_BOOTP_BOOTFILESIZE
2001 CONFIG_BOOTP_SEND_HOSTNAME
2002 CONFIG_BOOTP_NTPSERVER
2003 CONFIG_BOOTP_TIMEOFFSET
2004 CONFIG_BOOTP_VENDOREX
2005 CONFIG_BOOTP_MAY_FAIL
2007 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2008 environment variable, not the BOOTP server.
2010 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2011 after the configured retry count, the call will fail
2012 instead of starting over. This can be used to fail over
2013 to Link-local IP address configuration if the DHCP server
2016 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2017 serverip from a DHCP server, it is possible that more
2018 than one DNS serverip is offered to the client.
2019 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2020 serverip will be stored in the additional environment
2021 variable "dnsip2". The first DNS serverip is always
2022 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2025 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2026 to do a dynamic update of a DNS server. To do this, they
2027 need the hostname of the DHCP requester.
2028 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2029 of the "hostname" environment variable is passed as
2030 option 12 to the DHCP server.
2032 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2034 A 32bit value in microseconds for a delay between
2035 receiving a "DHCP Offer" and sending the "DHCP Request".
2036 This fixes a problem with certain DHCP servers that don't
2037 respond 100% of the time to a "DHCP request". E.g. On an
2038 AT91RM9200 processor running at 180MHz, this delay needed
2039 to be *at least* 15,000 usec before a Windows Server 2003
2040 DHCP server would reply 100% of the time. I recommend at
2041 least 50,000 usec to be safe. The alternative is to hope
2042 that one of the retries will be successful but note that
2043 the DHCP timeout and retry process takes a longer than
2046 - Link-local IP address negotiation:
2047 Negotiate with other link-local clients on the local network
2048 for an address that doesn't require explicit configuration.
2049 This is especially useful if a DHCP server cannot be guaranteed
2050 to exist in all environments that the device must operate.
2052 See doc/README.link-local for more information.
2055 CONFIG_CDP_DEVICE_ID
2057 The device id used in CDP trigger frames.
2059 CONFIG_CDP_DEVICE_ID_PREFIX
2061 A two character string which is prefixed to the MAC address
2066 A printf format string which contains the ascii name of
2067 the port. Normally is set to "eth%d" which sets
2068 eth0 for the first Ethernet, eth1 for the second etc.
2070 CONFIG_CDP_CAPABILITIES
2072 A 32bit integer which indicates the device capabilities;
2073 0x00000010 for a normal host which does not forwards.
2077 An ascii string containing the version of the software.
2081 An ascii string containing the name of the platform.
2085 A 32bit integer sent on the trigger.
2087 CONFIG_CDP_POWER_CONSUMPTION
2089 A 16bit integer containing the power consumption of the
2090 device in .1 of milliwatts.
2092 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2094 A byte containing the id of the VLAN.
2096 - Status LED: CONFIG_STATUS_LED
2098 Several configurations allow to display the current
2099 status using a LED. For instance, the LED will blink
2100 fast while running U-Boot code, stop blinking as
2101 soon as a reply to a BOOTP request was received, and
2102 start blinking slow once the Linux kernel is running
2103 (supported by a status LED driver in the Linux
2104 kernel). Defining CONFIG_STATUS_LED enables this
2110 The status LED can be connected to a GPIO pin.
2111 In such cases, the gpio_led driver can be used as a
2112 status LED backend implementation. Define CONFIG_GPIO_LED
2113 to include the gpio_led driver in the U-Boot binary.
2115 CONFIG_GPIO_LED_INVERTED_TABLE
2116 Some GPIO connected LEDs may have inverted polarity in which
2117 case the GPIO high value corresponds to LED off state and
2118 GPIO low value corresponds to LED on state.
2119 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2120 with a list of GPIO LEDs that have inverted polarity.
2122 - CAN Support: CONFIG_CAN_DRIVER
2124 Defining CONFIG_CAN_DRIVER enables CAN driver support
2125 on those systems that support this (optional)
2126 feature, like the TQM8xxL modules.
2128 - I2C Support: CONFIG_SYS_I2C
2130 This enable the NEW i2c subsystem, and will allow you to use
2131 i2c commands at the u-boot command line (as long as you set
2132 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2133 based realtime clock chips or other i2c devices. See
2134 common/cmd_i2c.c for a description of the command line
2137 ported i2c driver to the new framework:
2138 - drivers/i2c/soft_i2c.c:
2139 - activate first bus with CONFIG_SYS_I2C_SOFT define
2140 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2141 for defining speed and slave address
2142 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2143 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2144 for defining speed and slave address
2145 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2146 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2147 for defining speed and slave address
2148 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2149 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2150 for defining speed and slave address
2152 - drivers/i2c/fsl_i2c.c:
2153 - activate i2c driver with CONFIG_SYS_I2C_FSL
2154 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2155 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2156 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2158 - If your board supports a second fsl i2c bus, define
2159 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2160 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2161 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2164 - drivers/i2c/tegra_i2c.c:
2165 - activate this driver with CONFIG_SYS_I2C_TEGRA
2166 - This driver adds 4 i2c buses with a fix speed from
2167 100000 and the slave addr 0!
2169 - drivers/i2c/ppc4xx_i2c.c
2170 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2171 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2172 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2174 - drivers/i2c/i2c_mxc.c
2175 - activate this driver with CONFIG_SYS_I2C_MXC
2176 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2177 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2178 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2179 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2180 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2181 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2182 If thoses defines are not set, default value is 100000
2183 for speed, and 0 for slave.
2185 - drivers/i2c/rcar_i2c.c:
2186 - activate this driver with CONFIG_SYS_I2C_RCAR
2187 - This driver adds 4 i2c buses
2189 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2190 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2191 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2192 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2193 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2194 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2195 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2196 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2197 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2199 - drivers/i2c/sh_i2c.c:
2200 - activate this driver with CONFIG_SYS_I2C_SH
2201 - This driver adds from 2 to 5 i2c buses
2203 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2204 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2205 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2206 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2207 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2208 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2209 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2210 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2211 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2212 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2213 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2214 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2215 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2217 - drivers/i2c/omap24xx_i2c.c
2218 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2219 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2220 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2221 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2222 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2223 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2224 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2225 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2226 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2227 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2228 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2230 - drivers/i2c/zynq_i2c.c
2231 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2232 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2233 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2235 - drivers/i2c/s3c24x0_i2c.c:
2236 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2237 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2238 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2239 with a fix speed from 100000 and the slave addr 0!
2243 CONFIG_SYS_NUM_I2C_BUSES
2244 Hold the number of i2c busses you want to use. If you
2245 don't use/have i2c muxes on your i2c bus, this
2246 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2249 CONFIG_SYS_I2C_DIRECT_BUS
2250 define this, if you don't use i2c muxes on your hardware.
2251 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2254 CONFIG_SYS_I2C_MAX_HOPS
2255 define how many muxes are maximal consecutively connected
2256 on one i2c bus. If you not use i2c muxes, omit this
2259 CONFIG_SYS_I2C_BUSES
2260 hold a list of busses you want to use, only used if
2261 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2262 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2263 CONFIG_SYS_NUM_I2C_BUSES = 9:
2265 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2266 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2267 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2268 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2269 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2270 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2271 {1, {I2C_NULL_HOP}}, \
2272 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2273 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2277 bus 0 on adapter 0 without a mux
2278 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2279 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2280 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2281 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2282 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2283 bus 6 on adapter 1 without a mux
2284 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2285 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2287 If you do not have i2c muxes on your board, omit this define.
2289 - Legacy I2C Support: CONFIG_HARD_I2C
2291 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2292 provides the following compelling advantages:
2294 - more than one i2c adapter is usable
2295 - approved multibus support
2296 - better i2c mux support
2298 ** Please consider updating your I2C driver now. **
2300 These enable legacy I2C serial bus commands. Defining
2301 CONFIG_HARD_I2C will include the appropriate I2C driver
2302 for the selected CPU.
2304 This will allow you to use i2c commands at the u-boot
2305 command line (as long as you set CONFIG_CMD_I2C in
2306 CONFIG_COMMANDS) and communicate with i2c based realtime
2307 clock chips. See common/cmd_i2c.c for a description of the
2308 command line interface.
2310 CONFIG_HARD_I2C selects a hardware I2C controller.
2312 There are several other quantities that must also be
2313 defined when you define CONFIG_HARD_I2C.
2315 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2316 to be the frequency (in Hz) at which you wish your i2c bus
2317 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2318 the CPU's i2c node address).
2320 Now, the u-boot i2c code for the mpc8xx
2321 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2322 and so its address should therefore be cleared to 0 (See,
2323 eg, MPC823e User's Manual p.16-473). So, set
2324 CONFIG_SYS_I2C_SLAVE to 0.
2326 CONFIG_SYS_I2C_INIT_MPC5XXX
2328 When a board is reset during an i2c bus transfer
2329 chips might think that the current transfer is still
2330 in progress. Reset the slave devices by sending start
2331 commands until the slave device responds.
2333 That's all that's required for CONFIG_HARD_I2C.
2335 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2336 then the following macros need to be defined (examples are
2337 from include/configs/lwmon.h):
2341 (Optional). Any commands necessary to enable the I2C
2342 controller or configure ports.
2344 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2348 (Only for MPC8260 CPU). The I/O port to use (the code
2349 assumes both bits are on the same port). Valid values
2350 are 0..3 for ports A..D.
2354 The code necessary to make the I2C data line active
2355 (driven). If the data line is open collector, this
2358 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2362 The code necessary to make the I2C data line tri-stated
2363 (inactive). If the data line is open collector, this
2366 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2370 Code that returns true if the I2C data line is high,
2373 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2377 If <bit> is true, sets the I2C data line high. If it
2378 is false, it clears it (low).
2380 eg: #define I2C_SDA(bit) \
2381 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2382 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2386 If <bit> is true, sets the I2C clock line high. If it
2387 is false, it clears it (low).
2389 eg: #define I2C_SCL(bit) \
2390 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2391 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2395 This delay is invoked four times per clock cycle so this
2396 controls the rate of data transfer. The data rate thus
2397 is 1 / (I2C_DELAY * 4). Often defined to be something
2400 #define I2C_DELAY udelay(2)
2402 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2404 If your arch supports the generic GPIO framework (asm/gpio.h),
2405 then you may alternatively define the two GPIOs that are to be
2406 used as SCL / SDA. Any of the previous I2C_xxx macros will
2407 have GPIO-based defaults assigned to them as appropriate.
2409 You should define these to the GPIO value as given directly to
2410 the generic GPIO functions.
2412 CONFIG_SYS_I2C_INIT_BOARD
2414 When a board is reset during an i2c bus transfer
2415 chips might think that the current transfer is still
2416 in progress. On some boards it is possible to access
2417 the i2c SCLK line directly, either by using the
2418 processor pin as a GPIO or by having a second pin
2419 connected to the bus. If this option is defined a
2420 custom i2c_init_board() routine in boards/xxx/board.c
2421 is run early in the boot sequence.
2423 CONFIG_SYS_I2C_BOARD_LATE_INIT
2425 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2426 defined a custom i2c_board_late_init() routine in
2427 boards/xxx/board.c is run AFTER the operations in i2c_init()
2428 is completed. This callpoint can be used to unreset i2c bus
2429 using CPU i2c controller register accesses for CPUs whose i2c
2430 controller provide such a method. It is called at the end of
2431 i2c_init() to allow i2c_init operations to setup the i2c bus
2432 controller on the CPU (e.g. setting bus speed & slave address).
2434 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2436 This option enables configuration of bi_iic_fast[] flags
2437 in u-boot bd_info structure based on u-boot environment
2438 variable "i2cfast". (see also i2cfast)
2440 CONFIG_I2C_MULTI_BUS
2442 This option allows the use of multiple I2C buses, each of which
2443 must have a controller. At any point in time, only one bus is
2444 active. To switch to a different bus, use the 'i2c dev' command.
2445 Note that bus numbering is zero-based.
2447 CONFIG_SYS_I2C_NOPROBES
2449 This option specifies a list of I2C devices that will be skipped
2450 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2451 is set, specify a list of bus-device pairs. Otherwise, specify
2452 a 1D array of device addresses
2455 #undef CONFIG_I2C_MULTI_BUS
2456 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2458 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2460 #define CONFIG_I2C_MULTI_BUS
2461 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2463 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2465 CONFIG_SYS_SPD_BUS_NUM
2467 If defined, then this indicates the I2C bus number for DDR SPD.
2468 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2470 CONFIG_SYS_RTC_BUS_NUM
2472 If defined, then this indicates the I2C bus number for the RTC.
2473 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2475 CONFIG_SYS_DTT_BUS_NUM
2477 If defined, then this indicates the I2C bus number for the DTT.
2478 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2480 CONFIG_SYS_I2C_DTT_ADDR:
2482 If defined, specifies the I2C address of the DTT device.
2483 If not defined, then U-Boot uses predefined value for
2484 specified DTT device.
2486 CONFIG_SOFT_I2C_READ_REPEATED_START
2488 defining this will force the i2c_read() function in
2489 the soft_i2c driver to perform an I2C repeated start
2490 between writing the address pointer and reading the
2491 data. If this define is omitted the default behaviour
2492 of doing a stop-start sequence will be used. Most I2C
2493 devices can use either method, but some require one or
2496 - SPI Support: CONFIG_SPI
2498 Enables SPI driver (so far only tested with
2499 SPI EEPROM, also an instance works with Crystal A/D and
2500 D/As on the SACSng board)
2504 Enables the driver for SPI controller on SuperH. Currently
2505 only SH7757 is supported.
2509 Enables extended (16-bit) SPI EEPROM addressing.
2510 (symmetrical to CONFIG_I2C_X)
2514 Enables a software (bit-bang) SPI driver rather than
2515 using hardware support. This is a general purpose
2516 driver that only requires three general I/O port pins
2517 (two outputs, one input) to function. If this is
2518 defined, the board configuration must define several
2519 SPI configuration items (port pins to use, etc). For
2520 an example, see include/configs/sacsng.h.
2524 Enables a hardware SPI driver for general-purpose reads
2525 and writes. As with CONFIG_SOFT_SPI, the board configuration
2526 must define a list of chip-select function pointers.
2527 Currently supported on some MPC8xxx processors. For an
2528 example, see include/configs/mpc8349emds.h.
2532 Enables the driver for the SPI controllers on i.MX and MXC
2533 SoCs. Currently i.MX31/35/51 are supported.
2535 - FPGA Support: CONFIG_FPGA
2537 Enables FPGA subsystem.
2539 CONFIG_FPGA_<vendor>
2541 Enables support for specific chip vendors.
2544 CONFIG_FPGA_<family>
2546 Enables support for FPGA family.
2547 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2551 Specify the number of FPGA devices to support.
2553 CONFIG_SYS_FPGA_PROG_FEEDBACK
2555 Enable printing of hash marks during FPGA configuration.
2557 CONFIG_SYS_FPGA_CHECK_BUSY
2559 Enable checks on FPGA configuration interface busy
2560 status by the configuration function. This option
2561 will require a board or device specific function to
2566 If defined, a function that provides delays in the FPGA
2567 configuration driver.
2569 CONFIG_SYS_FPGA_CHECK_CTRLC
2570 Allow Control-C to interrupt FPGA configuration
2572 CONFIG_SYS_FPGA_CHECK_ERROR
2574 Check for configuration errors during FPGA bitfile
2575 loading. For example, abort during Virtex II
2576 configuration if the INIT_B line goes low (which
2577 indicated a CRC error).
2579 CONFIG_SYS_FPGA_WAIT_INIT
2581 Maximum time to wait for the INIT_B line to deassert
2582 after PROB_B has been deasserted during a Virtex II
2583 FPGA configuration sequence. The default time is 500
2586 CONFIG_SYS_FPGA_WAIT_BUSY
2588 Maximum time to wait for BUSY to deassert during
2589 Virtex II FPGA configuration. The default is 5 ms.
2591 CONFIG_SYS_FPGA_WAIT_CONFIG
2593 Time to wait after FPGA configuration. The default is
2596 - Configuration Management:
2599 If defined, this string will be added to the U-Boot
2600 version information (U_BOOT_VERSION)
2602 - Vendor Parameter Protection:
2604 U-Boot considers the values of the environment
2605 variables "serial#" (Board Serial Number) and
2606 "ethaddr" (Ethernet Address) to be parameters that
2607 are set once by the board vendor / manufacturer, and
2608 protects these variables from casual modification by
2609 the user. Once set, these variables are read-only,
2610 and write or delete attempts are rejected. You can
2611 change this behaviour:
2613 If CONFIG_ENV_OVERWRITE is #defined in your config
2614 file, the write protection for vendor parameters is
2615 completely disabled. Anybody can change or delete
2618 Alternatively, if you #define _both_ CONFIG_ETHADDR
2619 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2620 Ethernet address is installed in the environment,
2621 which can be changed exactly ONCE by the user. [The
2622 serial# is unaffected by this, i. e. it remains
2625 The same can be accomplished in a more flexible way
2626 for any variable by configuring the type of access
2627 to allow for those variables in the ".flags" variable
2628 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2633 Define this variable to enable the reservation of
2634 "protected RAM", i. e. RAM which is not overwritten
2635 by U-Boot. Define CONFIG_PRAM to hold the number of
2636 kB you want to reserve for pRAM. You can overwrite
2637 this default value by defining an environment
2638 variable "pram" to the number of kB you want to
2639 reserve. Note that the board info structure will
2640 still show the full amount of RAM. If pRAM is
2641 reserved, a new environment variable "mem" will
2642 automatically be defined to hold the amount of
2643 remaining RAM in a form that can be passed as boot
2644 argument to Linux, for instance like that:
2646 setenv bootargs ... mem=\${mem}
2649 This way you can tell Linux not to use this memory,
2650 either, which results in a memory region that will
2651 not be affected by reboots.
2653 *WARNING* If your board configuration uses automatic
2654 detection of the RAM size, you must make sure that
2655 this memory test is non-destructive. So far, the
2656 following board configurations are known to be
2659 IVMS8, IVML24, SPD8xx, TQM8xxL,
2660 HERMES, IP860, RPXlite, LWMON,
2663 - Access to physical memory region (> 4GB)
2664 Some basic support is provided for operations on memory not
2665 normally accessible to U-Boot - e.g. some architectures
2666 support access to more than 4GB of memory on 32-bit
2667 machines using physical address extension or similar.
2668 Define CONFIG_PHYSMEM to access this basic support, which
2669 currently only supports clearing the memory.
2674 Define this variable to stop the system in case of a
2675 fatal error, so that you have to reset it manually.
2676 This is probably NOT a good idea for an embedded
2677 system where you want the system to reboot
2678 automatically as fast as possible, but it may be
2679 useful during development since you can try to debug
2680 the conditions that lead to the situation.
2682 CONFIG_NET_RETRY_COUNT
2684 This variable defines the number of retries for
2685 network operations like ARP, RARP, TFTP, or BOOTP
2686 before giving up the operation. If not defined, a
2687 default value of 5 is used.
2691 Timeout waiting for an ARP reply in milliseconds.
2695 Timeout in milliseconds used in NFS protocol.
2696 If you encounter "ERROR: Cannot umount" in nfs command,
2697 try longer timeout such as
2698 #define CONFIG_NFS_TIMEOUT 10000UL
2700 - Command Interpreter:
2701 CONFIG_AUTO_COMPLETE
2703 Enable auto completion of commands using TAB.
2705 Note that this feature has NOT been implemented yet
2706 for the "hush" shell.
2709 CONFIG_SYS_HUSH_PARSER
2711 Define this variable to enable the "hush" shell (from
2712 Busybox) as command line interpreter, thus enabling
2713 powerful command line syntax like
2714 if...then...else...fi conditionals or `&&' and '||'
2715 constructs ("shell scripts").
2717 If undefined, you get the old, much simpler behaviour
2718 with a somewhat smaller memory footprint.
2721 CONFIG_SYS_PROMPT_HUSH_PS2
2723 This defines the secondary prompt string, which is
2724 printed when the command interpreter needs more input
2725 to complete a command. Usually "> ".
2729 In the current implementation, the local variables
2730 space and global environment variables space are
2731 separated. Local variables are those you define by
2732 simply typing `name=value'. To access a local
2733 variable later on, you have write `$name' or
2734 `${name}'; to execute the contents of a variable
2735 directly type `$name' at the command prompt.
2737 Global environment variables are those you use
2738 setenv/printenv to work with. To run a command stored
2739 in such a variable, you need to use the run command,
2740 and you must not use the '$' sign to access them.
2742 To store commands and special characters in a
2743 variable, please use double quotation marks
2744 surrounding the whole text of the variable, instead
2745 of the backslashes before semicolons and special
2748 - Commandline Editing and History:
2749 CONFIG_CMDLINE_EDITING
2751 Enable editing and History functions for interactive
2752 commandline input operations
2754 - Default Environment:
2755 CONFIG_EXTRA_ENV_SETTINGS
2757 Define this to contain any number of null terminated
2758 strings (variable = value pairs) that will be part of
2759 the default environment compiled into the boot image.
2761 For example, place something like this in your
2762 board's config file:
2764 #define CONFIG_EXTRA_ENV_SETTINGS \
2768 Warning: This method is based on knowledge about the
2769 internal format how the environment is stored by the
2770 U-Boot code. This is NOT an official, exported
2771 interface! Although it is unlikely that this format
2772 will change soon, there is no guarantee either.
2773 You better know what you are doing here.
2775 Note: overly (ab)use of the default environment is
2776 discouraged. Make sure to check other ways to preset
2777 the environment like the "source" command or the
2780 CONFIG_ENV_VARS_UBOOT_CONFIG
2782 Define this in order to add variables describing the
2783 U-Boot build configuration to the default environment.
2784 These will be named arch, cpu, board, vendor, and soc.
2786 Enabling this option will cause the following to be defined:
2794 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2796 Define this in order to add variables describing certain
2797 run-time determined information about the hardware to the
2798 environment. These will be named board_name, board_rev.
2800 CONFIG_DELAY_ENVIRONMENT
2802 Normally the environment is loaded when the board is
2803 intialised so that it is available to U-Boot. This inhibits
2804 that so that the environment is not available until
2805 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2806 this is instead controlled by the value of
2807 /config/load-environment.
2809 - DataFlash Support:
2810 CONFIG_HAS_DATAFLASH
2812 Defining this option enables DataFlash features and
2813 allows to read/write in Dataflash via the standard
2816 - Serial Flash support
2819 Defining this option enables SPI flash commands
2820 'sf probe/read/write/erase/update'.
2822 Usage requires an initial 'probe' to define the serial
2823 flash parameters, followed by read/write/erase/update
2826 The following defaults may be provided by the platform
2827 to handle the common case when only a single serial
2828 flash is present on the system.
2830 CONFIG_SF_DEFAULT_BUS Bus identifier
2831 CONFIG_SF_DEFAULT_CS Chip-select
2832 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2833 CONFIG_SF_DEFAULT_SPEED in Hz
2837 Define this option to include a destructive SPI flash
2840 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2842 Define this option to use the Bank addr/Extended addr
2843 support on SPI flashes which has size > 16Mbytes.
2845 CONFIG_SF_DUAL_FLASH Dual flash memories
2847 Define this option to use dual flash support where two flash
2848 memories can be connected with a given cs line.
2849 currently Xilinx Zynq qspi support these type of connections.
2851 - SystemACE Support:
2854 Adding this option adds support for Xilinx SystemACE
2855 chips attached via some sort of local bus. The address
2856 of the chip must also be defined in the
2857 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2859 #define CONFIG_SYSTEMACE
2860 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2862 When SystemACE support is added, the "ace" device type
2863 becomes available to the fat commands, i.e. fatls.
2865 - TFTP Fixed UDP Port:
2868 If this is defined, the environment variable tftpsrcp
2869 is used to supply the TFTP UDP source port value.
2870 If tftpsrcp isn't defined, the normal pseudo-random port
2871 number generator is used.
2873 Also, the environment variable tftpdstp is used to supply
2874 the TFTP UDP destination port value. If tftpdstp isn't
2875 defined, the normal port 69 is used.
2877 The purpose for tftpsrcp is to allow a TFTP server to
2878 blindly start the TFTP transfer using the pre-configured
2879 target IP address and UDP port. This has the effect of
2880 "punching through" the (Windows XP) firewall, allowing
2881 the remainder of the TFTP transfer to proceed normally.
2882 A better solution is to properly configure the firewall,
2883 but sometimes that is not allowed.
2888 This enables a generic 'hash' command which can produce
2889 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2893 Enable the hash verify command (hash -v). This adds to code
2896 CONFIG_SHA1 - support SHA1 hashing
2897 CONFIG_SHA256 - support SHA256 hashing
2899 Note: There is also a sha1sum command, which should perhaps
2900 be deprecated in favour of 'hash sha1'.
2902 - Freescale i.MX specific commands:
2903 CONFIG_CMD_HDMIDETECT
2904 This enables 'hdmidet' command which returns true if an
2905 HDMI monitor is detected. This command is i.MX 6 specific.
2908 This enables the 'bmode' (bootmode) command for forcing
2909 a boot from specific media.
2911 This is useful for forcing the ROM's usb downloader to
2912 activate upon a watchdog reset which is nice when iterating
2913 on U-Boot. Using the reset button or running bmode normal
2914 will set it back to normal. This command currently
2915 supports i.MX53 and i.MX6.
2920 This enables the RSA algorithm used for FIT image verification
2921 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2923 The signing part is build into mkimage regardless of this
2926 - bootcount support:
2927 CONFIG_BOOTCOUNT_LIMIT
2929 This enables the bootcounter support, see:
2930 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2933 enable special bootcounter support on at91sam9xe based boards.
2935 enable special bootcounter support on blackfin based boards.
2937 enable special bootcounter support on da850 based boards.
2938 CONFIG_BOOTCOUNT_RAM
2939 enable support for the bootcounter in RAM
2940 CONFIG_BOOTCOUNT_I2C
2941 enable support for the bootcounter on an i2c (like RTC) device.
2942 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2943 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2945 CONFIG_BOOTCOUNT_ALEN = address len
2947 - Show boot progress:
2948 CONFIG_SHOW_BOOT_PROGRESS
2950 Defining this option allows to add some board-
2951 specific code (calling a user-provided function
2952 "show_boot_progress(int)") that enables you to show
2953 the system's boot progress on some display (for
2954 example, some LED's) on your board. At the moment,
2955 the following checkpoints are implemented:
2957 - Detailed boot stage timing
2959 Define this option to get detailed timing of each stage
2960 of the boot process.
2962 CONFIG_BOOTSTAGE_USER_COUNT
2963 This is the number of available user bootstage records.
2964 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2965 a new ID will be allocated from this stash. If you exceed
2966 the limit, recording will stop.
2968 CONFIG_BOOTSTAGE_REPORT
2969 Define this to print a report before boot, similar to this:
2971 Timer summary in microseconds:
2974 3,575,678 3,575,678 board_init_f start
2975 3,575,695 17 arch_cpu_init A9
2976 3,575,777 82 arch_cpu_init done
2977 3,659,598 83,821 board_init_r start
2978 3,910,375 250,777 main_loop
2979 29,916,167 26,005,792 bootm_start
2980 30,361,327 445,160 start_kernel
2982 CONFIG_CMD_BOOTSTAGE
2983 Add a 'bootstage' command which supports printing a report
2984 and un/stashing of bootstage data.
2986 CONFIG_BOOTSTAGE_FDT
2987 Stash the bootstage information in the FDT. A root 'bootstage'
2988 node is created with each bootstage id as a child. Each child
2989 has a 'name' property and either 'mark' containing the
2990 mark time in microsecond, or 'accum' containing the
2991 accumulated time for that bootstage id in microseconds.
2996 name = "board_init_f";
3005 Code in the Linux kernel can find this in /proc/devicetree.
3007 Legacy uImage format:
3010 1 common/cmd_bootm.c before attempting to boot an image
3011 -1 common/cmd_bootm.c Image header has bad magic number
3012 2 common/cmd_bootm.c Image header has correct magic number
3013 -2 common/cmd_bootm.c Image header has bad checksum
3014 3 common/cmd_bootm.c Image header has correct checksum
3015 -3 common/cmd_bootm.c Image data has bad checksum
3016 4 common/cmd_bootm.c Image data has correct checksum
3017 -4 common/cmd_bootm.c Image is for unsupported architecture
3018 5 common/cmd_bootm.c Architecture check OK
3019 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3020 6 common/cmd_bootm.c Image Type check OK
3021 -6 common/cmd_bootm.c gunzip uncompression error
3022 -7 common/cmd_bootm.c Unimplemented compression type
3023 7 common/cmd_bootm.c Uncompression OK
3024 8 common/cmd_bootm.c No uncompress/copy overwrite error
3025 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3027 9 common/image.c Start initial ramdisk verification
3028 -10 common/image.c Ramdisk header has bad magic number
3029 -11 common/image.c Ramdisk header has bad checksum
3030 10 common/image.c Ramdisk header is OK
3031 -12 common/image.c Ramdisk data has bad checksum
3032 11 common/image.c Ramdisk data has correct checksum
3033 12 common/image.c Ramdisk verification complete, start loading
3034 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3035 13 common/image.c Start multifile image verification
3036 14 common/image.c No initial ramdisk, no multifile, continue.
3038 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3040 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3041 -31 post/post.c POST test failed, detected by post_output_backlog()
3042 -32 post/post.c POST test failed, detected by post_run_single()
3044 34 common/cmd_doc.c before loading a Image from a DOC device
3045 -35 common/cmd_doc.c Bad usage of "doc" command
3046 35 common/cmd_doc.c correct usage of "doc" command
3047 -36 common/cmd_doc.c No boot device
3048 36 common/cmd_doc.c correct boot device
3049 -37 common/cmd_doc.c Unknown Chip ID on boot device
3050 37 common/cmd_doc.c correct chip ID found, device available
3051 -38 common/cmd_doc.c Read Error on boot device
3052 38 common/cmd_doc.c reading Image header from DOC device OK
3053 -39 common/cmd_doc.c Image header has bad magic number
3054 39 common/cmd_doc.c Image header has correct magic number
3055 -40 common/cmd_doc.c Error reading Image from DOC device
3056 40 common/cmd_doc.c Image header has correct magic number
3057 41 common/cmd_ide.c before loading a Image from a IDE device
3058 -42 common/cmd_ide.c Bad usage of "ide" command
3059 42 common/cmd_ide.c correct usage of "ide" command
3060 -43 common/cmd_ide.c No boot device
3061 43 common/cmd_ide.c boot device found
3062 -44 common/cmd_ide.c Device not available
3063 44 common/cmd_ide.c Device available
3064 -45 common/cmd_ide.c wrong partition selected
3065 45 common/cmd_ide.c partition selected
3066 -46 common/cmd_ide.c Unknown partition table
3067 46 common/cmd_ide.c valid partition table found
3068 -47 common/cmd_ide.c Invalid partition type
3069 47 common/cmd_ide.c correct partition type
3070 -48 common/cmd_ide.c Error reading Image Header on boot device
3071 48 common/cmd_ide.c reading Image Header from IDE device OK
3072 -49 common/cmd_ide.c Image header has bad magic number
3073 49 common/cmd_ide.c Image header has correct magic number
3074 -50 common/cmd_ide.c Image header has bad checksum
3075 50 common/cmd_ide.c Image header has correct checksum
3076 -51 common/cmd_ide.c Error reading Image from IDE device
3077 51 common/cmd_ide.c reading Image from IDE device OK
3078 52 common/cmd_nand.c before loading a Image from a NAND device
3079 -53 common/cmd_nand.c Bad usage of "nand" command
3080 53 common/cmd_nand.c correct usage of "nand" command
3081 -54 common/cmd_nand.c No boot device
3082 54 common/cmd_nand.c boot device found
3083 -55 common/cmd_nand.c Unknown Chip ID on boot device
3084 55 common/cmd_nand.c correct chip ID found, device available
3085 -56 common/cmd_nand.c Error reading Image Header on boot device
3086 56 common/cmd_nand.c reading Image Header from NAND device OK
3087 -57 common/cmd_nand.c Image header has bad magic number
3088 57 common/cmd_nand.c Image header has correct magic number
3089 -58 common/cmd_nand.c Error reading Image from NAND device
3090 58 common/cmd_nand.c reading Image from NAND device OK
3092 -60 common/env_common.c Environment has a bad CRC, using default
3094 64 net/eth.c starting with Ethernet configuration.
3095 -64 net/eth.c no Ethernet found.
3096 65 net/eth.c Ethernet found.
3098 -80 common/cmd_net.c usage wrong
3099 80 common/cmd_net.c before calling NetLoop()
3100 -81 common/cmd_net.c some error in NetLoop() occurred
3101 81 common/cmd_net.c NetLoop() back without error
3102 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3103 82 common/cmd_net.c trying automatic boot
3104 83 common/cmd_net.c running "source" command
3105 -83 common/cmd_net.c some error in automatic boot or "source" command
3106 84 common/cmd_net.c end without errors
3111 100 common/cmd_bootm.c Kernel FIT Image has correct format
3112 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3113 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3114 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3115 102 common/cmd_bootm.c Kernel unit name specified
3116 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3117 103 common/cmd_bootm.c Found configuration node
3118 104 common/cmd_bootm.c Got kernel subimage node offset
3119 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3120 105 common/cmd_bootm.c Kernel subimage hash verification OK
3121 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3122 106 common/cmd_bootm.c Architecture check OK
3123 -106 common/cmd_bootm.c Kernel subimage has wrong type
3124 107 common/cmd_bootm.c Kernel subimage type OK
3125 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3126 108 common/cmd_bootm.c Got kernel subimage data/size
3127 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3128 -109 common/cmd_bootm.c Can't get kernel subimage type
3129 -110 common/cmd_bootm.c Can't get kernel subimage comp
3130 -111 common/cmd_bootm.c Can't get kernel subimage os
3131 -112 common/cmd_bootm.c Can't get kernel subimage load address
3132 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3134 120 common/image.c Start initial ramdisk verification
3135 -120 common/image.c Ramdisk FIT image has incorrect format
3136 121 common/image.c Ramdisk FIT image has correct format
3137 122 common/image.c No ramdisk subimage unit name, using configuration
3138 -122 common/image.c Can't get configuration for ramdisk subimage
3139 123 common/image.c Ramdisk unit name specified
3140 -124 common/image.c Can't get ramdisk subimage node offset
3141 125 common/image.c Got ramdisk subimage node offset
3142 -125 common/image.c Ramdisk subimage hash verification failed
3143 126 common/image.c Ramdisk subimage hash verification OK
3144 -126 common/image.c Ramdisk subimage for unsupported architecture
3145 127 common/image.c Architecture check OK
3146 -127 common/image.c Can't get ramdisk subimage data/size
3147 128 common/image.c Got ramdisk subimage data/size
3148 129 common/image.c Can't get ramdisk load address
3149 -129 common/image.c Got ramdisk load address
3151 -130 common/cmd_doc.c Incorrect FIT image format
3152 131 common/cmd_doc.c FIT image format OK
3154 -140 common/cmd_ide.c Incorrect FIT image format
3155 141 common/cmd_ide.c FIT image format OK
3157 -150 common/cmd_nand.c Incorrect FIT image format
3158 151 common/cmd_nand.c FIT image format OK
3160 - FIT image support:
3162 Enable support for the FIT uImage format.
3164 CONFIG_FIT_BEST_MATCH
3165 When no configuration is explicitly selected, default to the
3166 one whose fdt's compatibility field best matches that of
3167 U-Boot itself. A match is considered "best" if it matches the
3168 most specific compatibility entry of U-Boot's fdt's root node.
3169 The order of entries in the configuration's fdt is ignored.
3171 CONFIG_FIT_SIGNATURE
3172 This option enables signature verification of FIT uImages,
3173 using a hash signed and verified using RSA. See
3174 doc/uImage.FIT/signature.txt for more details.
3176 - Standalone program support:
3177 CONFIG_STANDALONE_LOAD_ADDR
3179 This option defines a board specific value for the
3180 address where standalone program gets loaded, thus
3181 overwriting the architecture dependent default
3184 - Frame Buffer Address:
3187 Define CONFIG_FB_ADDR if you want to use specific
3188 address for frame buffer. This is typically the case
3189 when using a graphics controller has separate video
3190 memory. U-Boot will then place the frame buffer at
3191 the given address instead of dynamically reserving it
3192 in system RAM by calling lcd_setmem(), which grabs
3193 the memory for the frame buffer depending on the
3194 configured panel size.
3196 Please see board_init_f function.
3198 - Automatic software updates via TFTP server
3200 CONFIG_UPDATE_TFTP_CNT_MAX
3201 CONFIG_UPDATE_TFTP_MSEC_MAX
3203 These options enable and control the auto-update feature;
3204 for a more detailed description refer to doc/README.update.
3206 - MTD Support (mtdparts command, UBI support)
3209 Adds the MTD device infrastructure from the Linux kernel.
3210 Needed for mtdparts command support.
3212 CONFIG_MTD_PARTITIONS
3214 Adds the MTD partitioning infrastructure from the Linux
3215 kernel. Needed for UBI support.
3220 Adds commands for interacting with MTD partitions formatted
3221 with the UBI flash translation layer
3223 Requires also defining CONFIG_RBTREE
3225 CONFIG_UBI_SILENCE_MSG
3227 Make the verbose messages from UBI stop printing. This leaves
3228 warnings and errors enabled.
3233 Adds commands for interacting with UBI volumes formatted as
3234 UBIFS. UBIFS is read-only in u-boot.
3236 Requires UBI support as well as CONFIG_LZO
3238 CONFIG_UBIFS_SILENCE_MSG
3240 Make the verbose messages from UBIFS stop printing. This leaves
3241 warnings and errors enabled.
3245 Enable building of SPL globally.
3248 LDSCRIPT for linking the SPL binary.
3250 CONFIG_SPL_MAX_FOOTPRINT
3251 Maximum size in memory allocated to the SPL, BSS included.
3252 When defined, the linker checks that the actual memory
3253 used by SPL from _start to __bss_end does not exceed it.
3254 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3255 must not be both defined at the same time.
3258 Maximum size of the SPL image (text, data, rodata, and
3259 linker lists sections), BSS excluded.
3260 When defined, the linker checks that the actual size does
3263 CONFIG_SPL_TEXT_BASE
3264 TEXT_BASE for linking the SPL binary.
3266 CONFIG_SPL_RELOC_TEXT_BASE
3267 Address to relocate to. If unspecified, this is equal to
3268 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3270 CONFIG_SPL_BSS_START_ADDR
3271 Link address for the BSS within the SPL binary.
3273 CONFIG_SPL_BSS_MAX_SIZE
3274 Maximum size in memory allocated to the SPL BSS.
3275 When defined, the linker checks that the actual memory used
3276 by SPL from __bss_start to __bss_end does not exceed it.
3277 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3278 must not be both defined at the same time.
3281 Adress of the start of the stack SPL will use
3283 CONFIG_SPL_RELOC_STACK
3284 Adress of the start of the stack SPL will use after
3285 relocation. If unspecified, this is equal to
3288 CONFIG_SYS_SPL_MALLOC_START
3289 Starting address of the malloc pool used in SPL.
3291 CONFIG_SYS_SPL_MALLOC_SIZE
3292 The size of the malloc pool used in SPL.
3294 CONFIG_SPL_FRAMEWORK
3295 Enable the SPL framework under common/. This framework
3296 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3297 NAND loading of the Linux Kernel.
3300 Enable booting directly to an OS from SPL.
3301 See also: doc/README.falcon
3303 CONFIG_SPL_DISPLAY_PRINT
3304 For ARM, enable an optional function to print more information
3305 about the running system.
3307 CONFIG_SPL_INIT_MINIMAL
3308 Arch init code should be built for a very small image
3310 CONFIG_SPL_LIBCOMMON_SUPPORT
3311 Support for common/libcommon.o in SPL binary
3313 CONFIG_SPL_LIBDISK_SUPPORT
3314 Support for disk/libdisk.o in SPL binary
3316 CONFIG_SPL_I2C_SUPPORT
3317 Support for drivers/i2c/libi2c.o in SPL binary
3319 CONFIG_SPL_GPIO_SUPPORT
3320 Support for drivers/gpio/libgpio.o in SPL binary
3322 CONFIG_SPL_MMC_SUPPORT
3323 Support for drivers/mmc/libmmc.o in SPL binary
3325 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3326 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3327 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3328 Address, size and partition on the MMC to load U-Boot from
3329 when the MMC is being used in raw mode.
3331 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3332 Sector to load kernel uImage from when MMC is being
3333 used in raw mode (for Falcon mode)
3335 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3336 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3337 Sector and number of sectors to load kernel argument
3338 parameters from when MMC is being used in raw mode
3341 CONFIG_SPL_FAT_SUPPORT
3342 Support for fs/fat/libfat.o in SPL binary
3344 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3345 Filename to read to load U-Boot when reading from FAT
3347 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3348 Filename to read to load kernel uImage when reading
3349 from FAT (for Falcon mode)
3351 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3352 Filename to read to load kernel argument parameters
3353 when reading from FAT (for Falcon mode)
3355 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3356 Set this for NAND SPL on PPC mpc83xx targets, so that
3357 start.S waits for the rest of the SPL to load before
3358 continuing (the hardware starts execution after just
3359 loading the first page rather than the full 4K).
3361 CONFIG_SPL_SKIP_RELOCATE
3362 Avoid SPL relocation
3364 CONFIG_SPL_NAND_BASE
3365 Include nand_base.c in the SPL. Requires
3366 CONFIG_SPL_NAND_DRIVERS.
3368 CONFIG_SPL_NAND_DRIVERS
3369 SPL uses normal NAND drivers, not minimal drivers.
3372 Include standard software ECC in the SPL
3374 CONFIG_SPL_NAND_SIMPLE
3375 Support for NAND boot using simple NAND drivers that
3376 expose the cmd_ctrl() interface.
3378 CONFIG_SPL_MTD_SUPPORT
3379 Support for the MTD subsystem within SPL. Useful for
3380 environment on NAND support within SPL.
3382 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3383 Set for the SPL on PPC mpc8xxx targets, support for
3384 drivers/ddr/fsl/libddr.o in SPL binary.
3386 CONFIG_SPL_COMMON_INIT_DDR
3387 Set for common ddr init with serial presence detect in
3390 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3391 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3392 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3393 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3394 CONFIG_SYS_NAND_ECCBYTES
3395 Defines the size and behavior of the NAND that SPL uses
3398 CONFIG_SPL_NAND_BOOT
3399 Add support NAND boot
3401 CONFIG_SYS_NAND_U_BOOT_OFFS
3402 Location in NAND to read U-Boot from
3404 CONFIG_SYS_NAND_U_BOOT_DST
3405 Location in memory to load U-Boot to
3407 CONFIG_SYS_NAND_U_BOOT_SIZE
3408 Size of image to load
3410 CONFIG_SYS_NAND_U_BOOT_START
3411 Entry point in loaded image to jump to
3413 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3414 Define this if you need to first read the OOB and then the
3415 data. This is used for example on davinci plattforms.
3417 CONFIG_SPL_OMAP3_ID_NAND
3418 Support for an OMAP3-specific set of functions to return the
3419 ID and MFR of the first attached NAND chip, if present.
3421 CONFIG_SPL_SERIAL_SUPPORT
3422 Support for drivers/serial/libserial.o in SPL binary
3424 CONFIG_SPL_SPI_FLASH_SUPPORT
3425 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3427 CONFIG_SPL_SPI_SUPPORT
3428 Support for drivers/spi/libspi.o in SPL binary
3430 CONFIG_SPL_RAM_DEVICE
3431 Support for running image already present in ram, in SPL binary
3433 CONFIG_SPL_LIBGENERIC_SUPPORT
3434 Support for lib/libgeneric.o in SPL binary
3436 CONFIG_SPL_ENV_SUPPORT
3437 Support for the environment operating in SPL binary
3439 CONFIG_SPL_NET_SUPPORT
3440 Support for the net/libnet.o in SPL binary.
3441 It conflicts with SPL env from storage medium specified by
3442 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3445 Image offset to which the SPL should be padded before appending
3446 the SPL payload. By default, this is defined as
3447 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3448 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3449 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3452 Final target image containing SPL and payload. Some SPLs
3453 use an arch-specific makefile fragment instead, for
3454 example if more than one image needs to be produced.
3456 CONFIG_FIT_SPL_PRINT
3457 Printing information about a FIT image adds quite a bit of
3458 code to SPL. So this is normally disabled in SPL. Use this
3459 option to re-enable it. This will affect the output of the
3460 bootm command when booting a FIT image.
3464 Enable building of TPL globally.
3467 Image offset to which the TPL should be padded before appending
3468 the TPL payload. By default, this is defined as
3469 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3470 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3471 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3476 [so far only for SMDK2400 boards]
3478 - Modem support enable:
3479 CONFIG_MODEM_SUPPORT
3481 - RTS/CTS Flow control enable:
3484 - Modem debug support:
3485 CONFIG_MODEM_SUPPORT_DEBUG
3487 Enables debugging stuff (char screen[1024], dbg())
3488 for modem support. Useful only with BDI2000.
3490 - Interrupt support (PPC):
3492 There are common interrupt_init() and timer_interrupt()
3493 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3494 for CPU specific initialization. interrupt_init_cpu()
3495 should set decrementer_count to appropriate value. If
3496 CPU resets decrementer automatically after interrupt
3497 (ppc4xx) it should set decrementer_count to zero.
3498 timer_interrupt() calls timer_interrupt_cpu() for CPU
3499 specific handling. If board has watchdog / status_led
3500 / other_activity_monitor it works automatically from
3501 general timer_interrupt().
3505 In the target system modem support is enabled when a
3506 specific key (key combination) is pressed during
3507 power-on. Otherwise U-Boot will boot normally
3508 (autoboot). The key_pressed() function is called from
3509 board_init(). Currently key_pressed() is a dummy
3510 function, returning 1 and thus enabling modem
3513 If there are no modem init strings in the
3514 environment, U-Boot proceed to autoboot; the
3515 previous output (banner, info printfs) will be
3518 See also: doc/README.Modem
3520 Board initialization settings:
3521 ------------------------------
3523 During Initialization u-boot calls a number of board specific functions
3524 to allow the preparation of board specific prerequisites, e.g. pin setup
3525 before drivers are initialized. To enable these callbacks the
3526 following configuration macros have to be defined. Currently this is
3527 architecture specific, so please check arch/your_architecture/lib/board.c
3528 typically in board_init_f() and board_init_r().
3530 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3531 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3532 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3533 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3535 Configuration Settings:
3536 -----------------------
3538 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3539 Optionally it can be defined to support 64-bit memory commands.
3541 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3542 undefine this when you're short of memory.
3544 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3545 width of the commands listed in the 'help' command output.
3547 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3548 prompt for user input.
3550 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3552 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3554 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3556 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3557 the application (usually a Linux kernel) when it is
3560 - CONFIG_SYS_BAUDRATE_TABLE:
3561 List of legal baudrate settings for this board.
3563 - CONFIG_SYS_CONSOLE_INFO_QUIET
3564 Suppress display of console information at boot.
3566 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3567 If the board specific function
3568 extern int overwrite_console (void);
3569 returns 1, the stdin, stderr and stdout are switched to the
3570 serial port, else the settings in the environment are used.
3572 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3573 Enable the call to overwrite_console().
3575 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3576 Enable overwrite of previous console environment settings.
3578 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3579 Begin and End addresses of the area used by the
3582 - CONFIG_SYS_ALT_MEMTEST:
3583 Enable an alternate, more extensive memory test.
3585 - CONFIG_SYS_MEMTEST_SCRATCH:
3586 Scratch address used by the alternate memory test
3587 You only need to set this if address zero isn't writeable
3589 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3590 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3591 this specified memory area will get subtracted from the top
3592 (end) of RAM and won't get "touched" at all by U-Boot. By
3593 fixing up gd->ram_size the Linux kernel should gets passed
3594 the now "corrected" memory size and won't touch it either.
3595 This should work for arch/ppc and arch/powerpc. Only Linux
3596 board ports in arch/powerpc with bootwrapper support that
3597 recalculate the memory size from the SDRAM controller setup
3598 will have to get fixed in Linux additionally.
3600 This option can be used as a workaround for the 440EPx/GRx
3601 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3604 WARNING: Please make sure that this value is a multiple of
3605 the Linux page size (normally 4k). If this is not the case,
3606 then the end address of the Linux memory will be located at a
3607 non page size aligned address and this could cause major
3610 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3611 Enable temporary baudrate change while serial download
3613 - CONFIG_SYS_SDRAM_BASE:
3614 Physical start address of SDRAM. _Must_ be 0 here.
3616 - CONFIG_SYS_MBIO_BASE:
3617 Physical start address of Motherboard I/O (if using a
3620 - CONFIG_SYS_FLASH_BASE:
3621 Physical start address of Flash memory.
3623 - CONFIG_SYS_MONITOR_BASE:
3624 Physical start address of boot monitor code (set by
3625 make config files to be same as the text base address
3626 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3627 CONFIG_SYS_FLASH_BASE when booting from flash.
3629 - CONFIG_SYS_MONITOR_LEN:
3630 Size of memory reserved for monitor code, used to
3631 determine _at_compile_time_ (!) if the environment is
3632 embedded within the U-Boot image, or in a separate
3635 - CONFIG_SYS_MALLOC_LEN:
3636 Size of DRAM reserved for malloc() use.
3638 - CONFIG_SYS_BOOTM_LEN:
3639 Normally compressed uImages are limited to an
3640 uncompressed size of 8 MBytes. If this is not enough,
3641 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3642 to adjust this setting to your needs.
3644 - CONFIG_SYS_BOOTMAPSZ:
3645 Maximum size of memory mapped by the startup code of
3646 the Linux kernel; all data that must be processed by
3647 the Linux kernel (bd_info, boot arguments, FDT blob if
3648 used) must be put below this limit, unless "bootm_low"
3649 environment variable is defined and non-zero. In such case
3650 all data for the Linux kernel must be between "bootm_low"
3651 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3652 variable "bootm_mapsize" will override the value of
3653 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3654 then the value in "bootm_size" will be used instead.
3656 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3657 Enable initrd_high functionality. If defined then the
3658 initrd_high feature is enabled and the bootm ramdisk subcommand
3661 - CONFIG_SYS_BOOT_GET_CMDLINE:
3662 Enables allocating and saving kernel cmdline in space between
3663 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3665 - CONFIG_SYS_BOOT_GET_KBD:
3666 Enables allocating and saving a kernel copy of the bd_info in
3667 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3669 - CONFIG_SYS_MAX_FLASH_BANKS:
3670 Max number of Flash memory banks
3672 - CONFIG_SYS_MAX_FLASH_SECT:
3673 Max number of sectors on a Flash chip
3675 - CONFIG_SYS_FLASH_ERASE_TOUT:
3676 Timeout for Flash erase operations (in ms)
3678 - CONFIG_SYS_FLASH_WRITE_TOUT:
3679 Timeout for Flash write operations (in ms)
3681 - CONFIG_SYS_FLASH_LOCK_TOUT
3682 Timeout for Flash set sector lock bit operation (in ms)
3684 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3685 Timeout for Flash clear lock bits operation (in ms)
3687 - CONFIG_SYS_FLASH_PROTECTION
3688 If defined, hardware flash sectors protection is used
3689 instead of U-Boot software protection.
3691 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3693 Enable TFTP transfers directly to flash memory;
3694 without this option such a download has to be
3695 performed in two steps: (1) download to RAM, and (2)
3696 copy from RAM to flash.
3698 The two-step approach is usually more reliable, since
3699 you can check if the download worked before you erase
3700 the flash, but in some situations (when system RAM is
3701 too limited to allow for a temporary copy of the
3702 downloaded image) this option may be very useful.
3704 - CONFIG_SYS_FLASH_CFI:
3705 Define if the flash driver uses extra elements in the
3706 common flash structure for storing flash geometry.
3708 - CONFIG_FLASH_CFI_DRIVER
3709 This option also enables the building of the cfi_flash driver
3710 in the drivers directory
3712 - CONFIG_FLASH_CFI_MTD
3713 This option enables the building of the cfi_mtd driver
3714 in the drivers directory. The driver exports CFI flash
3717 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3718 Use buffered writes to flash.
3720 - CONFIG_FLASH_SPANSION_S29WS_N
3721 s29ws-n MirrorBit flash has non-standard addresses for buffered
3724 - CONFIG_SYS_FLASH_QUIET_TEST
3725 If this option is defined, the common CFI flash doesn't
3726 print it's warning upon not recognized FLASH banks. This
3727 is useful, if some of the configured banks are only
3728 optionally available.
3730 - CONFIG_FLASH_SHOW_PROGRESS
3731 If defined (must be an integer), print out countdown
3732 digits and dots. Recommended value: 45 (9..1) for 80
3733 column displays, 15 (3..1) for 40 column displays.
3735 - CONFIG_FLASH_VERIFY
3736 If defined, the content of the flash (destination) is compared
3737 against the source after the write operation. An error message
3738 will be printed when the contents are not identical.
3739 Please note that this option is useless in nearly all cases,
3740 since such flash programming errors usually are detected earlier
3741 while unprotecting/erasing/programming. Please only enable
3742 this option if you really know what you are doing.
3744 - CONFIG_SYS_RX_ETH_BUFFER:
3745 Defines the number of Ethernet receive buffers. On some
3746 Ethernet controllers it is recommended to set this value
3747 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3748 buffers can be full shortly after enabling the interface
3749 on high Ethernet traffic.
3750 Defaults to 4 if not defined.
3752 - CONFIG_ENV_MAX_ENTRIES
3754 Maximum number of entries in the hash table that is used
3755 internally to store the environment settings. The default
3756 setting is supposed to be generous and should work in most
3757 cases. This setting can be used to tune behaviour; see
3758 lib/hashtable.c for details.
3760 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3761 - CONFIG_ENV_FLAGS_LIST_STATIC
3762 Enable validation of the values given to environment variables when
3763 calling env set. Variables can be restricted to only decimal,
3764 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3765 the variables can also be restricted to IP address or MAC address.
3767 The format of the list is:
3768 type_attribute = [s|d|x|b|i|m]
3769 access_atribute = [a|r|o|c]
3770 attributes = type_attribute[access_atribute]
3771 entry = variable_name[:attributes]
3774 The type attributes are:
3775 s - String (default)
3778 b - Boolean ([1yYtT|0nNfF])
3782 The access attributes are:
3788 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3789 Define this to a list (string) to define the ".flags"
3790 envirnoment variable in the default or embedded environment.
3792 - CONFIG_ENV_FLAGS_LIST_STATIC
3793 Define this to a list (string) to define validation that
3794 should be done if an entry is not found in the ".flags"
3795 environment variable. To override a setting in the static
3796 list, simply add an entry for the same variable name to the
3799 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3800 If defined, don't allow the -f switch to env set override variable
3803 - CONFIG_SYS_GENERIC_BOARD
3804 This selects the architecture-generic board system instead of the
3805 architecture-specific board files. It is intended to move boards
3806 to this new framework over time. Defining this will disable the
3807 arch/foo/lib/board.c file and use common/board_f.c and
3808 common/board_r.c instead. To use this option your architecture
3809 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3810 its config.mk file). If you find problems enabling this option on
3811 your board please report the problem and send patches!
3813 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3814 This is set by OMAP boards for the max time that reset should
3815 be asserted. See doc/README.omap-reset-time for details on how
3816 the value can be calulated on a given board.
3818 The following definitions that deal with the placement and management
3819 of environment data (variable area); in general, we support the
3820 following configurations:
3822 - CONFIG_BUILD_ENVCRC:
3824 Builds up envcrc with the target environment so that external utils
3825 may easily extract it and embed it in final U-Boot images.
3827 - CONFIG_ENV_IS_IN_FLASH:
3829 Define this if the environment is in flash memory.
3831 a) The environment occupies one whole flash sector, which is
3832 "embedded" in the text segment with the U-Boot code. This
3833 happens usually with "bottom boot sector" or "top boot
3834 sector" type flash chips, which have several smaller
3835 sectors at the start or the end. For instance, such a
3836 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3837 such a case you would place the environment in one of the
3838 4 kB sectors - with U-Boot code before and after it. With
3839 "top boot sector" type flash chips, you would put the
3840 environment in one of the last sectors, leaving a gap
3841 between U-Boot and the environment.
3843 - CONFIG_ENV_OFFSET:
3845 Offset of environment data (variable area) to the
3846 beginning of flash memory; for instance, with bottom boot
3847 type flash chips the second sector can be used: the offset
3848 for this sector is given here.
3850 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3854 This is just another way to specify the start address of
3855 the flash sector containing the environment (instead of
3858 - CONFIG_ENV_SECT_SIZE:
3860 Size of the sector containing the environment.
3863 b) Sometimes flash chips have few, equal sized, BIG sectors.
3864 In such a case you don't want to spend a whole sector for
3869 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3870 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3871 of this flash sector for the environment. This saves
3872 memory for the RAM copy of the environment.
3874 It may also save flash memory if you decide to use this
3875 when your environment is "embedded" within U-Boot code,
3876 since then the remainder of the flash sector could be used
3877 for U-Boot code. It should be pointed out that this is
3878 STRONGLY DISCOURAGED from a robustness point of view:
3879 updating the environment in flash makes it always
3880 necessary to erase the WHOLE sector. If something goes
3881 wrong before the contents has been restored from a copy in
3882 RAM, your target system will be dead.
3884 - CONFIG_ENV_ADDR_REDUND
3885 CONFIG_ENV_SIZE_REDUND
3887 These settings describe a second storage area used to hold
3888 a redundant copy of the environment data, so that there is
3889 a valid backup copy in case there is a power failure during
3890 a "saveenv" operation.
3892 BE CAREFUL! Any changes to the flash layout, and some changes to the
3893 source code will make it necessary to adapt <board>/u-boot.lds*
3897 - CONFIG_ENV_IS_IN_NVRAM:
3899 Define this if you have some non-volatile memory device
3900 (NVRAM, battery buffered SRAM) which you want to use for the
3906 These two #defines are used to determine the memory area you
3907 want to use for environment. It is assumed that this memory
3908 can just be read and written to, without any special
3911 BE CAREFUL! The first access to the environment happens quite early
3912 in U-Boot initalization (when we try to get the setting of for the
3913 console baudrate). You *MUST* have mapped your NVRAM area then, or
3916 Please note that even with NVRAM we still use a copy of the
3917 environment in RAM: we could work on NVRAM directly, but we want to
3918 keep settings there always unmodified except somebody uses "saveenv"
3919 to save the current settings.
3922 - CONFIG_ENV_IS_IN_EEPROM:
3924 Use this if you have an EEPROM or similar serial access
3925 device and a driver for it.
3927 - CONFIG_ENV_OFFSET:
3930 These two #defines specify the offset and size of the
3931 environment area within the total memory of your EEPROM.
3933 - CONFIG_SYS_I2C_EEPROM_ADDR:
3934 If defined, specified the chip address of the EEPROM device.
3935 The default address is zero.
3937 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3938 If defined, the number of bits used to address bytes in a
3939 single page in the EEPROM device. A 64 byte page, for example
3940 would require six bits.
3942 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3943 If defined, the number of milliseconds to delay between
3944 page writes. The default is zero milliseconds.
3946 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3947 The length in bytes of the EEPROM memory array address. Note
3948 that this is NOT the chip address length!
3950 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3951 EEPROM chips that implement "address overflow" are ones
3952 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3953 address and the extra bits end up in the "chip address" bit
3954 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3957 Note that we consider the length of the address field to
3958 still be one byte because the extra address bits are hidden
3959 in the chip address.
3961 - CONFIG_SYS_EEPROM_SIZE:
3962 The size in bytes of the EEPROM device.
3964 - CONFIG_ENV_EEPROM_IS_ON_I2C
3965 define this, if you have I2C and SPI activated, and your
3966 EEPROM, which holds the environment, is on the I2C bus.
3968 - CONFIG_I2C_ENV_EEPROM_BUS
3969 if you have an Environment on an EEPROM reached over
3970 I2C muxes, you can define here, how to reach this
3971 EEPROM. For example:
3973 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3975 EEPROM which holds the environment, is reached over
3976 a pca9547 i2c mux with address 0x70, channel 3.
3978 - CONFIG_ENV_IS_IN_DATAFLASH:
3980 Define this if you have a DataFlash memory device which you
3981 want to use for the environment.
3983 - CONFIG_ENV_OFFSET:
3987 These three #defines specify the offset and size of the
3988 environment area within the total memory of your DataFlash placed
3989 at the specified address.
3991 - CONFIG_ENV_IS_IN_REMOTE:
3993 Define this if you have a remote memory space which you
3994 want to use for the local device's environment.
3999 These two #defines specify the address and size of the
4000 environment area within the remote memory space. The
4001 local device can get the environment from remote memory
4002 space by SRIO or PCIE links.
4004 BE CAREFUL! For some special cases, the local device can not use
4005 "saveenv" command. For example, the local device will get the
4006 environment stored in a remote NOR flash by SRIO or PCIE link,
4007 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4009 - CONFIG_ENV_IS_IN_NAND:
4011 Define this if you have a NAND device which you want to use
4012 for the environment.
4014 - CONFIG_ENV_OFFSET:
4017 These two #defines specify the offset and size of the environment
4018 area within the first NAND device. CONFIG_ENV_OFFSET must be
4019 aligned to an erase block boundary.
4021 - CONFIG_ENV_OFFSET_REDUND (optional):
4023 This setting describes a second storage area of CONFIG_ENV_SIZE
4024 size used to hold a redundant copy of the environment data, so
4025 that there is a valid backup copy in case there is a power failure
4026 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4027 aligned to an erase block boundary.
4029 - CONFIG_ENV_RANGE (optional):
4031 Specifies the length of the region in which the environment
4032 can be written. This should be a multiple of the NAND device's
4033 block size. Specifying a range with more erase blocks than
4034 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4035 the range to be avoided.
4037 - CONFIG_ENV_OFFSET_OOB (optional):
4039 Enables support for dynamically retrieving the offset of the
4040 environment from block zero's out-of-band data. The
4041 "nand env.oob" command can be used to record this offset.
4042 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4043 using CONFIG_ENV_OFFSET_OOB.
4045 - CONFIG_NAND_ENV_DST
4047 Defines address in RAM to which the nand_spl code should copy the
4048 environment. If redundant environment is used, it will be copied to
4049 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4051 - CONFIG_ENV_IS_IN_UBI:
4053 Define this if you have an UBI volume that you want to use for the
4054 environment. This has the benefit of wear-leveling the environment
4055 accesses, which is important on NAND.
4057 - CONFIG_ENV_UBI_PART:
4059 Define this to a string that is the mtd partition containing the UBI.
4061 - CONFIG_ENV_UBI_VOLUME:
4063 Define this to the name of the volume that you want to store the
4066 - CONFIG_ENV_UBI_VOLUME_REDUND:
4068 Define this to the name of another volume to store a second copy of
4069 the environment in. This will enable redundant environments in UBI.
4070 It is assumed that both volumes are in the same MTD partition.
4072 - CONFIG_UBI_SILENCE_MSG
4073 - CONFIG_UBIFS_SILENCE_MSG
4075 You will probably want to define these to avoid a really noisy system
4076 when storing the env in UBI.
4078 - CONFIG_ENV_IS_IN_MMC:
4080 Define this if you have an MMC device which you want to use for the
4083 - CONFIG_SYS_MMC_ENV_DEV:
4085 Specifies which MMC device the environment is stored in.
4087 - CONFIG_SYS_MMC_ENV_PART (optional):
4089 Specifies which MMC partition the environment is stored in. If not
4090 set, defaults to partition 0, the user area. Common values might be
4091 1 (first MMC boot partition), 2 (second MMC boot partition).
4093 - CONFIG_ENV_OFFSET:
4096 These two #defines specify the offset and size of the environment
4097 area within the specified MMC device.
4099 If offset is positive (the usual case), it is treated as relative to
4100 the start of the MMC partition. If offset is negative, it is treated
4101 as relative to the end of the MMC partition. This can be useful if
4102 your board may be fitted with different MMC devices, which have
4103 different sizes for the MMC partitions, and you always want the
4104 environment placed at the very end of the partition, to leave the
4105 maximum possible space before it, to store other data.
4107 These two values are in units of bytes, but must be aligned to an
4108 MMC sector boundary.
4110 - CONFIG_ENV_OFFSET_REDUND (optional):
4112 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4113 hold a redundant copy of the environment data. This provides a
4114 valid backup copy in case the other copy is corrupted, e.g. due
4115 to a power failure during a "saveenv" operation.
4117 This value may also be positive or negative; this is handled in the
4118 same way as CONFIG_ENV_OFFSET.
4120 This value is also in units of bytes, but must also be aligned to
4121 an MMC sector boundary.
4123 - CONFIG_ENV_SIZE_REDUND (optional):
4125 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4126 set. If this value is set, it must be set to the same value as
4129 - CONFIG_SYS_SPI_INIT_OFFSET
4131 Defines offset to the initial SPI buffer area in DPRAM. The
4132 area is used at an early stage (ROM part) if the environment
4133 is configured to reside in the SPI EEPROM: We need a 520 byte
4134 scratch DPRAM area. It is used between the two initialization
4135 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4136 to be a good choice since it makes it far enough from the
4137 start of the data area as well as from the stack pointer.
4139 Please note that the environment is read-only until the monitor
4140 has been relocated to RAM and a RAM copy of the environment has been
4141 created; also, when using EEPROM you will have to use getenv_f()
4142 until then to read environment variables.
4144 The environment is protected by a CRC32 checksum. Before the monitor
4145 is relocated into RAM, as a result of a bad CRC you will be working
4146 with the compiled-in default environment - *silently*!!! [This is
4147 necessary, because the first environment variable we need is the
4148 "baudrate" setting for the console - if we have a bad CRC, we don't
4149 have any device yet where we could complain.]
4151 Note: once the monitor has been relocated, then it will complain if
4152 the default environment is used; a new CRC is computed as soon as you
4153 use the "saveenv" command to store a valid environment.
4155 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4156 Echo the inverted Ethernet link state to the fault LED.
4158 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4159 also needs to be defined.
4161 - CONFIG_SYS_FAULT_MII_ADDR:
4162 MII address of the PHY to check for the Ethernet link state.
4164 - CONFIG_NS16550_MIN_FUNCTIONS:
4165 Define this if you desire to only have use of the NS16550_init
4166 and NS16550_putc functions for the serial driver located at
4167 drivers/serial/ns16550.c. This option is useful for saving
4168 space for already greatly restricted images, including but not
4169 limited to NAND_SPL configurations.
4171 - CONFIG_DISPLAY_BOARDINFO
4172 Display information about the board that U-Boot is running on
4173 when U-Boot starts up. The board function checkboard() is called
4176 - CONFIG_DISPLAY_BOARDINFO_LATE
4177 Similar to the previous option, but display this information
4178 later, once stdio is running and output goes to the LCD, if
4181 Low Level (hardware related) configuration options:
4182 ---------------------------------------------------
4184 - CONFIG_SYS_CACHELINE_SIZE:
4185 Cache Line Size of the CPU.
4187 - CONFIG_SYS_DEFAULT_IMMR:
4188 Default address of the IMMR after system reset.
4190 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4191 and RPXsuper) to be able to adjust the position of
4192 the IMMR register after a reset.
4194 - CONFIG_SYS_CCSRBAR_DEFAULT:
4195 Default (power-on reset) physical address of CCSR on Freescale
4198 - CONFIG_SYS_CCSRBAR:
4199 Virtual address of CCSR. On a 32-bit build, this is typically
4200 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4202 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4203 for cross-platform code that uses that macro instead.
4205 - CONFIG_SYS_CCSRBAR_PHYS:
4206 Physical address of CCSR. CCSR can be relocated to a new
4207 physical address, if desired. In this case, this macro should
4208 be set to that address. Otherwise, it should be set to the
4209 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4210 is typically relocated on 36-bit builds. It is recommended
4211 that this macro be defined via the _HIGH and _LOW macros:
4213 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4214 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4216 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4217 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4218 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4219 used in assembly code, so it must not contain typecasts or
4220 integer size suffixes (e.g. "ULL").
4222 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4223 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4224 used in assembly code, so it must not contain typecasts or
4225 integer size suffixes (e.g. "ULL").
4227 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4228 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4229 forced to a value that ensures that CCSR is not relocated.
4231 - Floppy Disk Support:
4232 CONFIG_SYS_FDC_DRIVE_NUMBER
4234 the default drive number (default value 0)
4236 CONFIG_SYS_ISA_IO_STRIDE
4238 defines the spacing between FDC chipset registers
4241 CONFIG_SYS_ISA_IO_OFFSET
4243 defines the offset of register from address. It
4244 depends on which part of the data bus is connected to
4245 the FDC chipset. (default value 0)
4247 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4248 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4251 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4252 fdc_hw_init() is called at the beginning of the FDC
4253 setup. fdc_hw_init() must be provided by the board
4254 source code. It is used to make hardware dependant
4258 Most IDE controllers were designed to be connected with PCI
4259 interface. Only few of them were designed for AHB interface.
4260 When software is doing ATA command and data transfer to
4261 IDE devices through IDE-AHB controller, some additional
4262 registers accessing to these kind of IDE-AHB controller
4265 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4266 DO NOT CHANGE unless you know exactly what you're
4267 doing! (11-4) [MPC8xx/82xx systems only]
4269 - CONFIG_SYS_INIT_RAM_ADDR:
4271 Start address of memory area that can be used for
4272 initial data and stack; please note that this must be
4273 writable memory that is working WITHOUT special
4274 initialization, i. e. you CANNOT use normal RAM which
4275 will become available only after programming the
4276 memory controller and running certain initialization
4279 U-Boot uses the following memory types:
4280 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4281 - MPC824X: data cache
4282 - PPC4xx: data cache
4284 - CONFIG_SYS_GBL_DATA_OFFSET:
4286 Offset of the initial data structure in the memory
4287 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4288 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4289 data is located at the end of the available space
4290 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4291 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4292 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4293 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4296 On the MPC824X (or other systems that use the data
4297 cache for initial memory) the address chosen for
4298 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4299 point to an otherwise UNUSED address space between
4300 the top of RAM and the start of the PCI space.
4302 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4304 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4306 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4308 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4310 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4312 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4314 - CONFIG_SYS_OR_TIMING_SDRAM:
4317 - CONFIG_SYS_MAMR_PTA:
4318 periodic timer for refresh
4320 - CONFIG_SYS_DER: Debug Event Register (37-47)
4322 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4323 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4324 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4325 CONFIG_SYS_BR1_PRELIM:
4326 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4328 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4329 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4330 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4331 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4333 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4334 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4335 Machine Mode Register and Memory Periodic Timer
4336 Prescaler definitions (SDRAM timing)
4338 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4339 enable I2C microcode relocation patch (MPC8xx);
4340 define relocation offset in DPRAM [DSP2]
4342 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4343 enable SMC microcode relocation patch (MPC8xx);
4344 define relocation offset in DPRAM [SMC1]
4346 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4347 enable SPI microcode relocation patch (MPC8xx);
4348 define relocation offset in DPRAM [SCC4]
4350 - CONFIG_SYS_USE_OSCCLK:
4351 Use OSCM clock mode on MBX8xx board. Be careful,
4352 wrong setting might damage your board. Read
4353 doc/README.MBX before setting this variable!
4355 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4356 Offset of the bootmode word in DPRAM used by post
4357 (Power On Self Tests). This definition overrides
4358 #define'd default value in commproc.h resp.
4361 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4362 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4363 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4364 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4365 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4366 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4367 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4368 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4369 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4371 - CONFIG_PCI_DISABLE_PCIE:
4372 Disable PCI-Express on systems where it is supported but not
4375 - CONFIG_PCI_ENUM_ONLY
4376 Only scan through and get the devices on the busses.
4377 Don't do any setup work, presumably because someone or
4378 something has already done it, and we don't need to do it
4379 a second time. Useful for platforms that are pre-booted
4380 by coreboot or similar.
4382 - CONFIG_PCI_INDIRECT_BRIDGE:
4383 Enable support for indirect PCI bridges.
4386 Chip has SRIO or not
4389 Board has SRIO 1 port available
4392 Board has SRIO 2 port available
4394 - CONFIG_SRIO_PCIE_BOOT_MASTER
4395 Board can support master function for Boot from SRIO and PCIE
4397 - CONFIG_SYS_SRIOn_MEM_VIRT:
4398 Virtual Address of SRIO port 'n' memory region
4400 - CONFIG_SYS_SRIOn_MEM_PHYS:
4401 Physical Address of SRIO port 'n' memory region
4403 - CONFIG_SYS_SRIOn_MEM_SIZE:
4404 Size of SRIO port 'n' memory region
4406 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4407 Defined to tell the NAND controller that the NAND chip is using
4409 Not all NAND drivers use this symbol.
4410 Example of drivers that use it:
4411 - drivers/mtd/nand/ndfc.c
4412 - drivers/mtd/nand/mxc_nand.c
4414 - CONFIG_SYS_NDFC_EBC0_CFG
4415 Sets the EBC0_CFG register for the NDFC. If not defined
4416 a default value will be used.
4419 Get DDR timing information from an I2C EEPROM. Common
4420 with pluggable memory modules such as SODIMMs
4423 I2C address of the SPD EEPROM
4425 - CONFIG_SYS_SPD_BUS_NUM
4426 If SPD EEPROM is on an I2C bus other than the first
4427 one, specify here. Note that the value must resolve
4428 to something your driver can deal with.
4430 - CONFIG_SYS_DDR_RAW_TIMING
4431 Get DDR timing information from other than SPD. Common with
4432 soldered DDR chips onboard without SPD. DDR raw timing
4433 parameters are extracted from datasheet and hard-coded into
4434 header files or board specific files.
4436 - CONFIG_FSL_DDR_INTERACTIVE
4437 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4439 - CONFIG_SYS_83XX_DDR_USES_CS0
4440 Only for 83xx systems. If specified, then DDR should
4441 be configured using CS0 and CS1 instead of CS2 and CS3.
4443 - CONFIG_ETHER_ON_FEC[12]
4444 Define to enable FEC[12] on a 8xx series processor.
4446 - CONFIG_FEC[12]_PHY
4447 Define to the hardcoded PHY address which corresponds
4448 to the given FEC; i. e.
4449 #define CONFIG_FEC1_PHY 4
4450 means that the PHY with address 4 is connected to FEC1
4452 When set to -1, means to probe for first available.
4454 - CONFIG_FEC[12]_PHY_NORXERR
4455 The PHY does not have a RXERR line (RMII only).
4456 (so program the FEC to ignore it).
4459 Enable RMII mode for all FECs.
4460 Note that this is a global option, we can't
4461 have one FEC in standard MII mode and another in RMII mode.
4463 - CONFIG_CRC32_VERIFY
4464 Add a verify option to the crc32 command.
4467 => crc32 -v <address> <count> <crc32>
4469 Where address/count indicate a memory area
4470 and crc32 is the correct crc32 which the
4474 Add the "loopw" memory command. This only takes effect if
4475 the memory commands are activated globally (CONFIG_CMD_MEM).
4478 Add the "mdc" and "mwc" memory commands. These are cyclic
4483 This command will print 4 bytes (10,11,12,13) each 500 ms.
4485 => mwc.l 100 12345678 10
4486 This command will write 12345678 to address 100 all 10 ms.
4488 This only takes effect if the memory commands are activated
4489 globally (CONFIG_CMD_MEM).
4491 - CONFIG_SKIP_LOWLEVEL_INIT
4492 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4493 low level initializations (like setting up the memory
4494 controller) are omitted and/or U-Boot does not
4495 relocate itself into RAM.
4497 Normally this variable MUST NOT be defined. The only
4498 exception is when U-Boot is loaded (to RAM) by some
4499 other boot loader or by a debugger which performs
4500 these initializations itself.
4503 Modifies the behaviour of start.S when compiling a loader
4504 that is executed before the actual U-Boot. E.g. when
4505 compiling a NAND SPL.
4508 Modifies the behaviour of start.S when compiling a loader
4509 that is executed after the SPL and before the actual U-Boot.
4510 It is loaded by the SPL.
4512 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4513 Only for 85xx systems. If this variable is specified, the section
4514 .resetvec is not kept and the section .bootpg is placed in the
4515 previous 4k of the .text section.
4517 - CONFIG_ARCH_MAP_SYSMEM
4518 Generally U-Boot (and in particular the md command) uses
4519 effective address. It is therefore not necessary to regard
4520 U-Boot address as virtual addresses that need to be translated
4521 to physical addresses. However, sandbox requires this, since
4522 it maintains its own little RAM buffer which contains all
4523 addressable memory. This option causes some memory accesses
4524 to be mapped through map_sysmem() / unmap_sysmem().
4526 - CONFIG_USE_ARCH_MEMCPY
4527 CONFIG_USE_ARCH_MEMSET
4528 If these options are used a optimized version of memcpy/memset will
4529 be used if available. These functions may be faster under some
4530 conditions but may increase the binary size.
4532 - CONFIG_X86_RESET_VECTOR
4533 If defined, the x86 reset vector code is included. This is not
4534 needed when U-Boot is running from Coreboot.
4537 Defines the MPU clock speed (in MHz).
4539 NOTE : currently only supported on AM335x platforms.
4541 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4542 Enables the RTC32K OSC on AM33xx based plattforms
4544 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4545 Option to disable subpage write in NAND driver
4546 driver that uses this:
4547 drivers/mtd/nand/davinci_nand.c
4549 Freescale QE/FMAN Firmware Support:
4550 -----------------------------------
4552 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4553 loading of "firmware", which is encoded in the QE firmware binary format.
4554 This firmware often needs to be loaded during U-Boot booting, so macros
4555 are used to identify the storage device (NOR flash, SPI, etc) and the address
4558 - CONFIG_SYS_FMAN_FW_ADDR
4559 The address in the storage device where the FMAN microcode is located. The
4560 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4563 - CONFIG_SYS_QE_FW_ADDR
4564 The address in the storage device where the QE microcode is located. The
4565 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4568 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4569 The maximum possible size of the firmware. The firmware binary format
4570 has a field that specifies the actual size of the firmware, but it
4571 might not be possible to read any part of the firmware unless some
4572 local storage is allocated to hold the entire firmware first.
4574 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4575 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4576 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4577 virtual address in NOR flash.
4579 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4580 Specifies that QE/FMAN firmware is located in NAND flash.
4581 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4583 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4584 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4585 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4587 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4588 Specifies that QE/FMAN firmware is located on the primary SPI
4589 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4591 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4592 Specifies that QE/FMAN firmware is located in the remote (master)
4593 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4594 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4595 window->master inbound window->master LAW->the ucode address in
4596 master's memory space.
4598 Building the Software:
4599 ======================
4601 Building U-Boot has been tested in several native build environments
4602 and in many different cross environments. Of course we cannot support
4603 all possibly existing versions of cross development tools in all
4604 (potentially obsolete) versions. In case of tool chain problems we
4605 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4606 which is extensively used to build and test U-Boot.
4608 If you are not using a native environment, it is assumed that you
4609 have GNU cross compiling tools available in your path. In this case,
4610 you must set the environment variable CROSS_COMPILE in your shell.
4611 Note that no changes to the Makefile or any other source files are
4612 necessary. For example using the ELDK on a 4xx CPU, please enter:
4614 $ CROSS_COMPILE=ppc_4xx-
4615 $ export CROSS_COMPILE
4617 Note: If you wish to generate Windows versions of the utilities in
4618 the tools directory you can use the MinGW toolchain
4619 (http://www.mingw.org). Set your HOST tools to the MinGW
4620 toolchain and execute 'make tools'. For example:
4622 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4624 Binaries such as tools/mkimage.exe will be created which can
4625 be executed on computers running Windows.
4627 U-Boot is intended to be simple to build. After installing the
4628 sources you must configure U-Boot for one specific board type. This
4633 where "NAME_config" is the name of one of the existing configu-
4634 rations; see boards.cfg for supported names.
4636 Note: for some board special configuration names may exist; check if
4637 additional information is available from the board vendor; for
4638 instance, the TQM823L systems are available without (standard)
4639 or with LCD support. You can select such additional "features"
4640 when choosing the configuration, i. e.
4643 - will configure for a plain TQM823L, i. e. no LCD support
4645 make TQM823L_LCD_config
4646 - will configure for a TQM823L with U-Boot console on LCD
4651 Finally, type "make all", and you should get some working U-Boot
4652 images ready for download to / installation on your system:
4654 - "u-boot.bin" is a raw binary image
4655 - "u-boot" is an image in ELF binary format
4656 - "u-boot.srec" is in Motorola S-Record format
4658 By default the build is performed locally and the objects are saved
4659 in the source directory. One of the two methods can be used to change
4660 this behavior and build U-Boot to some external directory:
4662 1. Add O= to the make command line invocations:
4664 make O=/tmp/build distclean
4665 make O=/tmp/build NAME_config
4666 make O=/tmp/build all
4668 2. Set environment variable BUILD_DIR to point to the desired location:
4670 export BUILD_DIR=/tmp/build
4675 Note that the command line "O=" setting overrides the BUILD_DIR environment
4679 Please be aware that the Makefiles assume you are using GNU make, so
4680 for instance on NetBSD you might need to use "gmake" instead of
4684 If the system board that you have is not listed, then you will need
4685 to port U-Boot to your hardware platform. To do this, follow these
4688 1. Add a new configuration option for your board to the toplevel
4689 "boards.cfg" file, using the existing entries as examples.
4690 Follow the instructions there to keep the boards in order.
4691 2. Create a new directory to hold your board specific code. Add any
4692 files you need. In your board directory, you will need at least
4693 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4694 3. Create a new configuration file "include/configs/<board>.h" for
4696 3. If you're porting U-Boot to a new CPU, then also create a new
4697 directory to hold your CPU specific code. Add any files you need.
4698 4. Run "make <board>_config" with your new name.
4699 5. Type "make", and you should get a working "u-boot.srec" file
4700 to be installed on your target system.
4701 6. Debug and solve any problems that might arise.
4702 [Of course, this last step is much harder than it sounds.]
4705 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4706 ==============================================================
4708 If you have modified U-Boot sources (for instance added a new board
4709 or support for new devices, a new CPU, etc.) you are expected to
4710 provide feedback to the other developers. The feedback normally takes
4711 the form of a "patch", i. e. a context diff against a certain (latest
4712 official or latest in the git repository) version of U-Boot sources.
4714 But before you submit such a patch, please verify that your modifi-
4715 cation did not break existing code. At least make sure that *ALL* of
4716 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4717 just run the "MAKEALL" script, which will configure and build U-Boot
4718 for ALL supported system. Be warned, this will take a while. You can
4719 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4720 environment variable to the script, i. e. to use the ELDK cross tools
4723 CROSS_COMPILE=ppc_8xx- MAKEALL
4725 or to build on a native PowerPC system you can type
4727 CROSS_COMPILE=' ' MAKEALL
4729 When using the MAKEALL script, the default behaviour is to build
4730 U-Boot in the source directory. This location can be changed by
4731 setting the BUILD_DIR environment variable. Also, for each target
4732 built, the MAKEALL script saves two log files (<target>.ERR and
4733 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4734 location can be changed by setting the MAKEALL_LOGDIR environment
4735 variable. For example:
4737 export BUILD_DIR=/tmp/build
4738 export MAKEALL_LOGDIR=/tmp/log
4739 CROSS_COMPILE=ppc_8xx- MAKEALL
4741 With the above settings build objects are saved in the /tmp/build,
4742 log files are saved in the /tmp/log and the source tree remains clean
4743 during the whole build process.
4746 See also "U-Boot Porting Guide" below.
4749 Monitor Commands - Overview:
4750 ============================
4752 go - start application at address 'addr'
4753 run - run commands in an environment variable
4754 bootm - boot application image from memory
4755 bootp - boot image via network using BootP/TFTP protocol
4756 bootz - boot zImage from memory
4757 tftpboot- boot image via network using TFTP protocol
4758 and env variables "ipaddr" and "serverip"
4759 (and eventually "gatewayip")
4760 tftpput - upload a file via network using TFTP protocol
4761 rarpboot- boot image via network using RARP/TFTP protocol
4762 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4763 loads - load S-Record file over serial line
4764 loadb - load binary file over serial line (kermit mode)
4766 mm - memory modify (auto-incrementing)
4767 nm - memory modify (constant address)
4768 mw - memory write (fill)
4770 cmp - memory compare
4771 crc32 - checksum calculation
4772 i2c - I2C sub-system
4773 sspi - SPI utility commands
4774 base - print or set address offset
4775 printenv- print environment variables
4776 setenv - set environment variables
4777 saveenv - save environment variables to persistent storage
4778 protect - enable or disable FLASH write protection
4779 erase - erase FLASH memory
4780 flinfo - print FLASH memory information
4781 nand - NAND memory operations (see doc/README.nand)
4782 bdinfo - print Board Info structure
4783 iminfo - print header information for application image
4784 coninfo - print console devices and informations
4785 ide - IDE sub-system
4786 loop - infinite loop on address range
4787 loopw - infinite write loop on address range
4788 mtest - simple RAM test
4789 icache - enable or disable instruction cache
4790 dcache - enable or disable data cache
4791 reset - Perform RESET of the CPU
4792 echo - echo args to console
4793 version - print monitor version
4794 help - print online help
4795 ? - alias for 'help'
4798 Monitor Commands - Detailed Description:
4799 ========================================
4803 For now: just type "help <command>".
4806 Environment Variables:
4807 ======================
4809 U-Boot supports user configuration using Environment Variables which
4810 can be made persistent by saving to Flash memory.
4812 Environment Variables are set using "setenv", printed using
4813 "printenv", and saved to Flash using "saveenv". Using "setenv"
4814 without a value can be used to delete a variable from the
4815 environment. As long as you don't save the environment you are
4816 working with an in-memory copy. In case the Flash area containing the
4817 environment is erased by accident, a default environment is provided.
4819 Some configuration options can be set using Environment Variables.
4821 List of environment variables (most likely not complete):
4823 baudrate - see CONFIG_BAUDRATE
4825 bootdelay - see CONFIG_BOOTDELAY
4827 bootcmd - see CONFIG_BOOTCOMMAND
4829 bootargs - Boot arguments when booting an RTOS image
4831 bootfile - Name of the image to load with TFTP
4833 bootm_low - Memory range available for image processing in the bootm
4834 command can be restricted. This variable is given as
4835 a hexadecimal number and defines lowest address allowed
4836 for use by the bootm command. See also "bootm_size"
4837 environment variable. Address defined by "bootm_low" is
4838 also the base of the initial memory mapping for the Linux
4839 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4842 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4843 This variable is given as a hexadecimal number and it
4844 defines the size of the memory region starting at base
4845 address bootm_low that is accessible by the Linux kernel
4846 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4847 as the default value if it is defined, and bootm_size is
4850 bootm_size - Memory range available for image processing in the bootm
4851 command can be restricted. This variable is given as
4852 a hexadecimal number and defines the size of the region
4853 allowed for use by the bootm command. See also "bootm_low"
4854 environment variable.
4856 updatefile - Location of the software update file on a TFTP server, used
4857 by the automatic software update feature. Please refer to
4858 documentation in doc/README.update for more details.
4860 autoload - if set to "no" (any string beginning with 'n'),
4861 "bootp" will just load perform a lookup of the
4862 configuration from the BOOTP server, but not try to
4863 load any image using TFTP
4865 autostart - if set to "yes", an image loaded using the "bootp",
4866 "rarpboot", "tftpboot" or "diskboot" commands will
4867 be automatically started (by internally calling
4870 If set to "no", a standalone image passed to the
4871 "bootm" command will be copied to the load address
4872 (and eventually uncompressed), but NOT be started.
4873 This can be used to load and uncompress arbitrary
4876 fdt_high - if set this restricts the maximum address that the
4877 flattened device tree will be copied into upon boot.
4878 For example, if you have a system with 1 GB memory
4879 at physical address 0x10000000, while Linux kernel
4880 only recognizes the first 704 MB as low memory, you
4881 may need to set fdt_high as 0x3C000000 to have the
4882 device tree blob be copied to the maximum address
4883 of the 704 MB low memory, so that Linux kernel can
4884 access it during the boot procedure.
4886 If this is set to the special value 0xFFFFFFFF then
4887 the fdt will not be copied at all on boot. For this
4888 to work it must reside in writable memory, have
4889 sufficient padding on the end of it for u-boot to
4890 add the information it needs into it, and the memory
4891 must be accessible by the kernel.
4893 fdtcontroladdr- if set this is the address of the control flattened
4894 device tree used by U-Boot when CONFIG_OF_CONTROL is
4897 i2cfast - (PPC405GP|PPC405EP only)
4898 if set to 'y' configures Linux I2C driver for fast
4899 mode (400kHZ). This environment variable is used in
4900 initialization code. So, for changes to be effective
4901 it must be saved and board must be reset.
4903 initrd_high - restrict positioning of initrd images:
4904 If this variable is not set, initrd images will be
4905 copied to the highest possible address in RAM; this
4906 is usually what you want since it allows for
4907 maximum initrd size. If for some reason you want to
4908 make sure that the initrd image is loaded below the
4909 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4910 variable to a value of "no" or "off" or "0".
4911 Alternatively, you can set it to a maximum upper
4912 address to use (U-Boot will still check that it
4913 does not overwrite the U-Boot stack and data).
4915 For instance, when you have a system with 16 MB
4916 RAM, and want to reserve 4 MB from use by Linux,
4917 you can do this by adding "mem=12M" to the value of
4918 the "bootargs" variable. However, now you must make
4919 sure that the initrd image is placed in the first
4920 12 MB as well - this can be done with
4922 setenv initrd_high 00c00000
4924 If you set initrd_high to 0xFFFFFFFF, this is an
4925 indication to U-Boot that all addresses are legal
4926 for the Linux kernel, including addresses in flash
4927 memory. In this case U-Boot will NOT COPY the
4928 ramdisk at all. This may be useful to reduce the
4929 boot time on your system, but requires that this
4930 feature is supported by your Linux kernel.
4932 ipaddr - IP address; needed for tftpboot command
4934 loadaddr - Default load address for commands like "bootp",
4935 "rarpboot", "tftpboot", "loadb" or "diskboot"
4937 loads_echo - see CONFIG_LOADS_ECHO
4939 serverip - TFTP server IP address; needed for tftpboot command
4941 bootretry - see CONFIG_BOOT_RETRY_TIME
4943 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4945 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4947 ethprime - controls which interface is used first.
4949 ethact - controls which interface is currently active.
4950 For example you can do the following
4952 => setenv ethact FEC
4953 => ping 192.168.0.1 # traffic sent on FEC
4954 => setenv ethact SCC
4955 => ping 10.0.0.1 # traffic sent on SCC
4957 ethrotate - When set to "no" U-Boot does not go through all
4958 available network interfaces.
4959 It just stays at the currently selected interface.
4961 netretry - When set to "no" each network operation will
4962 either succeed or fail without retrying.
4963 When set to "once" the network operation will
4964 fail when all the available network interfaces
4965 are tried once without success.
4966 Useful on scripts which control the retry operation
4969 npe_ucode - set load address for the NPE microcode
4971 silent_linux - If set then linux will be told to boot silently, by
4972 changing the console to be empty. If "yes" it will be
4973 made silent. If "no" it will not be made silent. If
4974 unset, then it will be made silent if the U-Boot console
4977 tftpsrcport - If this is set, the value is used for TFTP's
4980 tftpdstport - If this is set, the value is used for TFTP's UDP
4981 destination port instead of the Well Know Port 69.
4983 tftpblocksize - Block size to use for TFTP transfers; if not set,
4984 we use the TFTP server's default block size
4986 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4987 seconds, minimum value is 1000 = 1 second). Defines
4988 when a packet is considered to be lost so it has to
4989 be retransmitted. The default is 5000 = 5 seconds.
4990 Lowering this value may make downloads succeed
4991 faster in networks with high packet loss rates or
4992 with unreliable TFTP servers.
4994 vlan - When set to a value < 4095 the traffic over
4995 Ethernet is encapsulated/received over 802.1q
4998 The following image location variables contain the location of images
4999 used in booting. The "Image" column gives the role of the image and is
5000 not an environment variable name. The other columns are environment
5001 variable names. "File Name" gives the name of the file on a TFTP
5002 server, "RAM Address" gives the location in RAM the image will be
5003 loaded to, and "Flash Location" gives the image's address in NOR
5004 flash or offset in NAND flash.
5006 *Note* - these variables don't have to be defined for all boards, some
5007 boards currenlty use other variables for these purposes, and some
5008 boards use these variables for other purposes.
5010 Image File Name RAM Address Flash Location
5011 ----- --------- ----------- --------------
5012 u-boot u-boot u-boot_addr_r u-boot_addr
5013 Linux kernel bootfile kernel_addr_r kernel_addr
5014 device tree blob fdtfile fdt_addr_r fdt_addr
5015 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5017 The following environment variables may be used and automatically
5018 updated by the network boot commands ("bootp" and "rarpboot"),
5019 depending the information provided by your boot server:
5021 bootfile - see above
5022 dnsip - IP address of your Domain Name Server
5023 dnsip2 - IP address of your secondary Domain Name Server
5024 gatewayip - IP address of the Gateway (Router) to use
5025 hostname - Target hostname
5027 netmask - Subnet Mask
5028 rootpath - Pathname of the root filesystem on the NFS server
5029 serverip - see above
5032 There are two special Environment Variables:
5034 serial# - contains hardware identification information such
5035 as type string and/or serial number
5036 ethaddr - Ethernet address
5038 These variables can be set only once (usually during manufacturing of
5039 the board). U-Boot refuses to delete or overwrite these variables
5040 once they have been set once.
5043 Further special Environment Variables:
5045 ver - Contains the U-Boot version string as printed
5046 with the "version" command. This variable is
5047 readonly (see CONFIG_VERSION_VARIABLE).
5050 Please note that changes to some configuration parameters may take
5051 only effect after the next boot (yes, that's just like Windoze :-).
5054 Callback functions for environment variables:
5055 ---------------------------------------------
5057 For some environment variables, the behavior of u-boot needs to change
5058 when their values are changed. This functionailty allows functions to
5059 be associated with arbitrary variables. On creation, overwrite, or
5060 deletion, the callback will provide the opportunity for some side
5061 effect to happen or for the change to be rejected.
5063 The callbacks are named and associated with a function using the
5064 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5066 These callbacks are associated with variables in one of two ways. The
5067 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5068 in the board configuration to a string that defines a list of
5069 associations. The list must be in the following format:
5071 entry = variable_name[:callback_name]
5074 If the callback name is not specified, then the callback is deleted.
5075 Spaces are also allowed anywhere in the list.
5077 Callbacks can also be associated by defining the ".callbacks" variable
5078 with the same list format above. Any association in ".callbacks" will
5079 override any association in the static list. You can define
5080 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5081 ".callbacks" envirnoment variable in the default or embedded environment.
5084 Command Line Parsing:
5085 =====================
5087 There are two different command line parsers available with U-Boot:
5088 the old "simple" one, and the much more powerful "hush" shell:
5090 Old, simple command line parser:
5091 --------------------------------
5093 - supports environment variables (through setenv / saveenv commands)
5094 - several commands on one line, separated by ';'
5095 - variable substitution using "... ${name} ..." syntax
5096 - special characters ('$', ';') can be escaped by prefixing with '\',
5098 setenv bootcmd bootm \${address}
5099 - You can also escape text by enclosing in single apostrophes, for example:
5100 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5105 - similar to Bourne shell, with control structures like
5106 if...then...else...fi, for...do...done; while...do...done,
5107 until...do...done, ...
5108 - supports environment ("global") variables (through setenv / saveenv
5109 commands) and local shell variables (through standard shell syntax
5110 "name=value"); only environment variables can be used with "run"
5116 (1) If a command line (or an environment variable executed by a "run"
5117 command) contains several commands separated by semicolon, and
5118 one of these commands fails, then the remaining commands will be
5121 (2) If you execute several variables with one call to run (i. e.
5122 calling run with a list of variables as arguments), any failing
5123 command will cause "run" to terminate, i. e. the remaining
5124 variables are not executed.
5126 Note for Redundant Ethernet Interfaces:
5127 =======================================
5129 Some boards come with redundant Ethernet interfaces; U-Boot supports
5130 such configurations and is capable of automatic selection of a
5131 "working" interface when needed. MAC assignment works as follows:
5133 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5134 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5135 "eth1addr" (=>eth1), "eth2addr", ...
5137 If the network interface stores some valid MAC address (for instance
5138 in SROM), this is used as default address if there is NO correspon-
5139 ding setting in the environment; if the corresponding environment
5140 variable is set, this overrides the settings in the card; that means:
5142 o If the SROM has a valid MAC address, and there is no address in the
5143 environment, the SROM's address is used.
5145 o If there is no valid address in the SROM, and a definition in the
5146 environment exists, then the value from the environment variable is
5149 o If both the SROM and the environment contain a MAC address, and
5150 both addresses are the same, this MAC address is used.
5152 o If both the SROM and the environment contain a MAC address, and the
5153 addresses differ, the value from the environment is used and a
5156 o If neither SROM nor the environment contain a MAC address, an error
5159 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5160 will be programmed into hardware as part of the initialization process. This
5161 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5162 The naming convention is as follows:
5163 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5168 U-Boot is capable of booting (and performing other auxiliary operations on)
5169 images in two formats:
5171 New uImage format (FIT)
5172 -----------------------
5174 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5175 to Flattened Device Tree). It allows the use of images with multiple
5176 components (several kernels, ramdisks, etc.), with contents protected by
5177 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5183 Old image format is based on binary files which can be basically anything,
5184 preceded by a special header; see the definitions in include/image.h for
5185 details; basically, the header defines the following image properties:
5187 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5188 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5189 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5190 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5192 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5193 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5194 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5195 * Compression Type (uncompressed, gzip, bzip2)
5201 The header is marked by a special Magic Number, and both the header
5202 and the data portions of the image are secured against corruption by
5209 Although U-Boot should support any OS or standalone application
5210 easily, the main focus has always been on Linux during the design of
5213 U-Boot includes many features that so far have been part of some
5214 special "boot loader" code within the Linux kernel. Also, any
5215 "initrd" images to be used are no longer part of one big Linux image;
5216 instead, kernel and "initrd" are separate images. This implementation
5217 serves several purposes:
5219 - the same features can be used for other OS or standalone
5220 applications (for instance: using compressed images to reduce the
5221 Flash memory footprint)
5223 - it becomes much easier to port new Linux kernel versions because
5224 lots of low-level, hardware dependent stuff are done by U-Boot
5226 - the same Linux kernel image can now be used with different "initrd"
5227 images; of course this also means that different kernel images can
5228 be run with the same "initrd". This makes testing easier (you don't
5229 have to build a new "zImage.initrd" Linux image when you just
5230 change a file in your "initrd"). Also, a field-upgrade of the
5231 software is easier now.
5237 Porting Linux to U-Boot based systems:
5238 ---------------------------------------
5240 U-Boot cannot save you from doing all the necessary modifications to
5241 configure the Linux device drivers for use with your target hardware
5242 (no, we don't intend to provide a full virtual machine interface to
5245 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5247 Just make sure your machine specific header file (for instance
5248 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5249 Information structure as we define in include/asm-<arch>/u-boot.h,
5250 and make sure that your definition of IMAP_ADDR uses the same value
5251 as your U-Boot configuration in CONFIG_SYS_IMMR.
5254 Configuring the Linux kernel:
5255 -----------------------------
5257 No specific requirements for U-Boot. Make sure you have some root
5258 device (initial ramdisk, NFS) for your target system.
5261 Building a Linux Image:
5262 -----------------------
5264 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5265 not used. If you use recent kernel source, a new build target
5266 "uImage" will exist which automatically builds an image usable by
5267 U-Boot. Most older kernels also have support for a "pImage" target,
5268 which was introduced for our predecessor project PPCBoot and uses a
5269 100% compatible format.
5278 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5279 encapsulate a compressed Linux kernel image with header information,
5280 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5282 * build a standard "vmlinux" kernel image (in ELF binary format):
5284 * convert the kernel into a raw binary image:
5286 ${CROSS_COMPILE}-objcopy -O binary \
5287 -R .note -R .comment \
5288 -S vmlinux linux.bin
5290 * compress the binary image:
5294 * package compressed binary image for U-Boot:
5296 mkimage -A ppc -O linux -T kernel -C gzip \
5297 -a 0 -e 0 -n "Linux Kernel Image" \
5298 -d linux.bin.gz uImage
5301 The "mkimage" tool can also be used to create ramdisk images for use
5302 with U-Boot, either separated from the Linux kernel image, or
5303 combined into one file. "mkimage" encapsulates the images with a 64
5304 byte header containing information about target architecture,
5305 operating system, image type, compression method, entry points, time
5306 stamp, CRC32 checksums, etc.
5308 "mkimage" can be called in two ways: to verify existing images and
5309 print the header information, or to build new images.
5311 In the first form (with "-l" option) mkimage lists the information
5312 contained in the header of an existing U-Boot image; this includes
5313 checksum verification:
5315 tools/mkimage -l image
5316 -l ==> list image header information
5318 The second form (with "-d" option) is used to build a U-Boot image
5319 from a "data file" which is used as image payload:
5321 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5322 -n name -d data_file image
5323 -A ==> set architecture to 'arch'
5324 -O ==> set operating system to 'os'
5325 -T ==> set image type to 'type'
5326 -C ==> set compression type 'comp'
5327 -a ==> set load address to 'addr' (hex)
5328 -e ==> set entry point to 'ep' (hex)
5329 -n ==> set image name to 'name'
5330 -d ==> use image data from 'datafile'
5332 Right now, all Linux kernels for PowerPC systems use the same load
5333 address (0x00000000), but the entry point address depends on the
5336 - 2.2.x kernels have the entry point at 0x0000000C,
5337 - 2.3.x and later kernels have the entry point at 0x00000000.
5339 So a typical call to build a U-Boot image would read:
5341 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5342 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5343 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5344 > examples/uImage.TQM850L
5345 Image Name: 2.4.4 kernel for TQM850L
5346 Created: Wed Jul 19 02:34:59 2000
5347 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5348 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5349 Load Address: 0x00000000
5350 Entry Point: 0x00000000
5352 To verify the contents of the image (or check for corruption):
5354 -> tools/mkimage -l examples/uImage.TQM850L
5355 Image Name: 2.4.4 kernel for TQM850L
5356 Created: Wed Jul 19 02:34:59 2000
5357 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5358 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5359 Load Address: 0x00000000
5360 Entry Point: 0x00000000
5362 NOTE: for embedded systems where boot time is critical you can trade
5363 speed for memory and install an UNCOMPRESSED image instead: this
5364 needs more space in Flash, but boots much faster since it does not
5365 need to be uncompressed:
5367 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5368 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5369 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5370 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5371 > examples/uImage.TQM850L-uncompressed
5372 Image Name: 2.4.4 kernel for TQM850L
5373 Created: Wed Jul 19 02:34:59 2000
5374 Image Type: PowerPC Linux Kernel Image (uncompressed)
5375 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5376 Load Address: 0x00000000
5377 Entry Point: 0x00000000
5380 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5381 when your kernel is intended to use an initial ramdisk:
5383 -> tools/mkimage -n 'Simple Ramdisk Image' \
5384 > -A ppc -O linux -T ramdisk -C gzip \
5385 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5386 Image Name: Simple Ramdisk Image
5387 Created: Wed Jan 12 14:01:50 2000
5388 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5389 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5390 Load Address: 0x00000000
5391 Entry Point: 0x00000000
5393 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5394 option performs the converse operation of the mkimage's second form (the "-d"
5395 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5398 tools/dumpimage -i image -p position data_file
5399 -i ==> extract from the 'image' a specific 'data_file', \
5400 indexed by 'position'
5403 Installing a Linux Image:
5404 -------------------------
5406 To downloading a U-Boot image over the serial (console) interface,
5407 you must convert the image to S-Record format:
5409 objcopy -I binary -O srec examples/image examples/image.srec
5411 The 'objcopy' does not understand the information in the U-Boot
5412 image header, so the resulting S-Record file will be relative to
5413 address 0x00000000. To load it to a given address, you need to
5414 specify the target address as 'offset' parameter with the 'loads'
5417 Example: install the image to address 0x40100000 (which on the
5418 TQM8xxL is in the first Flash bank):
5420 => erase 40100000 401FFFFF
5426 ## Ready for S-Record download ...
5427 ~>examples/image.srec
5428 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5430 15989 15990 15991 15992
5431 [file transfer complete]
5433 ## Start Addr = 0x00000000
5436 You can check the success of the download using the 'iminfo' command;
5437 this includes a checksum verification so you can be sure no data
5438 corruption happened:
5442 ## Checking Image at 40100000 ...
5443 Image Name: 2.2.13 for initrd on TQM850L
5444 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5445 Data Size: 335725 Bytes = 327 kB = 0 MB
5446 Load Address: 00000000
5447 Entry Point: 0000000c
5448 Verifying Checksum ... OK
5454 The "bootm" command is used to boot an application that is stored in
5455 memory (RAM or Flash). In case of a Linux kernel image, the contents
5456 of the "bootargs" environment variable is passed to the kernel as
5457 parameters. You can check and modify this variable using the
5458 "printenv" and "setenv" commands:
5461 => printenv bootargs
5462 bootargs=root=/dev/ram
5464 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5466 => printenv bootargs
5467 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5470 ## Booting Linux kernel at 40020000 ...
5471 Image Name: 2.2.13 for NFS on TQM850L
5472 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5473 Data Size: 381681 Bytes = 372 kB = 0 MB
5474 Load Address: 00000000
5475 Entry Point: 0000000c
5476 Verifying Checksum ... OK
5477 Uncompressing Kernel Image ... OK
5478 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
5479 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5480 time_init: decrementer frequency = 187500000/60
5481 Calibrating delay loop... 49.77 BogoMIPS
5482 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5485 If you want to boot a Linux kernel with initial RAM disk, you pass
5486 the memory addresses of both the kernel and the initrd image (PPBCOOT
5487 format!) to the "bootm" command:
5489 => imi 40100000 40200000
5491 ## Checking Image at 40100000 ...
5492 Image Name: 2.2.13 for initrd on TQM850L
5493 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5494 Data Size: 335725 Bytes = 327 kB = 0 MB
5495 Load Address: 00000000
5496 Entry Point: 0000000c
5497 Verifying Checksum ... OK
5499 ## Checking Image at 40200000 ...
5500 Image Name: Simple Ramdisk Image
5501 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5502 Data Size: 566530 Bytes = 553 kB = 0 MB
5503 Load Address: 00000000
5504 Entry Point: 00000000
5505 Verifying Checksum ... OK
5507 => bootm 40100000 40200000
5508 ## Booting Linux kernel at 40100000 ...
5509 Image Name: 2.2.13 for initrd on TQM850L
5510 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5511 Data Size: 335725 Bytes = 327 kB = 0 MB
5512 Load Address: 00000000
5513 Entry Point: 0000000c
5514 Verifying Checksum ... OK
5515 Uncompressing Kernel Image ... OK
5516 ## Loading RAMDisk Image at 40200000 ...
5517 Image Name: Simple Ramdisk Image
5518 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5519 Data Size: 566530 Bytes = 553 kB = 0 MB
5520 Load Address: 00000000
5521 Entry Point: 00000000
5522 Verifying Checksum ... OK
5523 Loading Ramdisk ... OK
5524 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
5525 Boot arguments: root=/dev/ram
5526 time_init: decrementer frequency = 187500000/60
5527 Calibrating delay loop... 49.77 BogoMIPS
5529 RAMDISK: Compressed image found at block 0
5530 VFS: Mounted root (ext2 filesystem).
5534 Boot Linux and pass a flat device tree:
5537 First, U-Boot must be compiled with the appropriate defines. See the section
5538 titled "Linux Kernel Interface" above for a more in depth explanation. The
5539 following is an example of how to start a kernel and pass an updated
5545 oft=oftrees/mpc8540ads.dtb
5546 => tftp $oftaddr $oft
5547 Speed: 1000, full duplex
5549 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5550 Filename 'oftrees/mpc8540ads.dtb'.
5551 Load address: 0x300000
5554 Bytes transferred = 4106 (100a hex)
5555 => tftp $loadaddr $bootfile
5556 Speed: 1000, full duplex
5558 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5560 Load address: 0x200000
5561 Loading:############
5563 Bytes transferred = 1029407 (fb51f hex)
5568 => bootm $loadaddr - $oftaddr
5569 ## Booting image at 00200000 ...
5570 Image Name: Linux-2.6.17-dirty
5571 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5572 Data Size: 1029343 Bytes = 1005.2 kB
5573 Load Address: 00000000
5574 Entry Point: 00000000
5575 Verifying Checksum ... OK
5576 Uncompressing Kernel Image ... OK
5577 Booting using flat device tree at 0x300000
5578 Using MPC85xx ADS machine description
5579 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5583 More About U-Boot Image Types:
5584 ------------------------------
5586 U-Boot supports the following image types:
5588 "Standalone Programs" are directly runnable in the environment
5589 provided by U-Boot; it is expected that (if they behave
5590 well) you can continue to work in U-Boot after return from
5591 the Standalone Program.
5592 "OS Kernel Images" are usually images of some Embedded OS which
5593 will take over control completely. Usually these programs
5594 will install their own set of exception handlers, device
5595 drivers, set up the MMU, etc. - this means, that you cannot
5596 expect to re-enter U-Boot except by resetting the CPU.
5597 "RAMDisk Images" are more or less just data blocks, and their
5598 parameters (address, size) are passed to an OS kernel that is
5600 "Multi-File Images" contain several images, typically an OS
5601 (Linux) kernel image and one or more data images like
5602 RAMDisks. This construct is useful for instance when you want
5603 to boot over the network using BOOTP etc., where the boot
5604 server provides just a single image file, but you want to get
5605 for instance an OS kernel and a RAMDisk image.
5607 "Multi-File Images" start with a list of image sizes, each
5608 image size (in bytes) specified by an "uint32_t" in network
5609 byte order. This list is terminated by an "(uint32_t)0".
5610 Immediately after the terminating 0 follow the images, one by
5611 one, all aligned on "uint32_t" boundaries (size rounded up to
5612 a multiple of 4 bytes).
5614 "Firmware Images" are binary images containing firmware (like
5615 U-Boot or FPGA images) which usually will be programmed to
5618 "Script files" are command sequences that will be executed by
5619 U-Boot's command interpreter; this feature is especially
5620 useful when you configure U-Boot to use a real shell (hush)
5621 as command interpreter.
5623 Booting the Linux zImage:
5624 -------------------------
5626 On some platforms, it's possible to boot Linux zImage. This is done
5627 using the "bootz" command. The syntax of "bootz" command is the same
5628 as the syntax of "bootm" command.
5630 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5631 kernel with raw initrd images. The syntax is slightly different, the
5632 address of the initrd must be augmented by it's size, in the following
5633 format: "<initrd addres>:<initrd size>".
5639 One of the features of U-Boot is that you can dynamically load and
5640 run "standalone" applications, which can use some resources of
5641 U-Boot like console I/O functions or interrupt services.
5643 Two simple examples are included with the sources:
5648 'examples/hello_world.c' contains a small "Hello World" Demo
5649 application; it is automatically compiled when you build U-Boot.
5650 It's configured to run at address 0x00040004, so you can play with it
5654 ## Ready for S-Record download ...
5655 ~>examples/hello_world.srec
5656 1 2 3 4 5 6 7 8 9 10 11 ...
5657 [file transfer complete]
5659 ## Start Addr = 0x00040004
5661 => go 40004 Hello World! This is a test.
5662 ## Starting application at 0x00040004 ...
5673 Hit any key to exit ...
5675 ## Application terminated, rc = 0x0
5677 Another example, which demonstrates how to register a CPM interrupt
5678 handler with the U-Boot code, can be found in 'examples/timer.c'.
5679 Here, a CPM timer is set up to generate an interrupt every second.
5680 The interrupt service routine is trivial, just printing a '.'
5681 character, but this is just a demo program. The application can be
5682 controlled by the following keys:
5684 ? - print current values og the CPM Timer registers
5685 b - enable interrupts and start timer
5686 e - stop timer and disable interrupts
5687 q - quit application
5690 ## Ready for S-Record download ...
5691 ~>examples/timer.srec
5692 1 2 3 4 5 6 7 8 9 10 11 ...
5693 [file transfer complete]
5695 ## Start Addr = 0x00040004
5698 ## Starting application at 0x00040004 ...
5701 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5704 [q, b, e, ?] Set interval 1000000 us
5707 [q, b, e, ?] ........
5708 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5711 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5714 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5717 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5719 [q, b, e, ?] ...Stopping timer
5721 [q, b, e, ?] ## Application terminated, rc = 0x0
5727 Over time, many people have reported problems when trying to use the
5728 "minicom" terminal emulation program for serial download. I (wd)
5729 consider minicom to be broken, and recommend not to use it. Under
5730 Unix, I recommend to use C-Kermit for general purpose use (and
5731 especially for kermit binary protocol download ("loadb" command), and
5732 use "cu" for S-Record download ("loads" command). See
5733 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5734 for help with kermit.
5737 Nevertheless, if you absolutely want to use it try adding this
5738 configuration to your "File transfer protocols" section:
5740 Name Program Name U/D FullScr IO-Red. Multi
5741 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5742 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5748 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5749 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5751 Building requires a cross environment; it is known to work on
5752 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5753 need gmake since the Makefiles are not compatible with BSD make).
5754 Note that the cross-powerpc package does not install include files;
5755 attempting to build U-Boot will fail because <machine/ansi.h> is
5756 missing. This file has to be installed and patched manually:
5758 # cd /usr/pkg/cross/powerpc-netbsd/include
5760 # ln -s powerpc machine
5761 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5762 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5764 Native builds *don't* work due to incompatibilities between native
5765 and U-Boot include files.
5767 Booting assumes that (the first part of) the image booted is a
5768 stage-2 loader which in turn loads and then invokes the kernel
5769 proper. Loader sources will eventually appear in the NetBSD source
5770 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5771 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5774 Implementation Internals:
5775 =========================
5777 The following is not intended to be a complete description of every
5778 implementation detail. However, it should help to understand the
5779 inner workings of U-Boot and make it easier to port it to custom
5783 Initial Stack, Global Data:
5784 ---------------------------
5786 The implementation of U-Boot is complicated by the fact that U-Boot
5787 starts running out of ROM (flash memory), usually without access to
5788 system RAM (because the memory controller is not initialized yet).
5789 This means that we don't have writable Data or BSS segments, and BSS
5790 is not initialized as zero. To be able to get a C environment working
5791 at all, we have to allocate at least a minimal stack. Implementation
5792 options for this are defined and restricted by the CPU used: Some CPU
5793 models provide on-chip memory (like the IMMR area on MPC8xx and
5794 MPC826x processors), on others (parts of) the data cache can be
5795 locked as (mis-) used as memory, etc.
5797 Chris Hallinan posted a good summary of these issues to the
5798 U-Boot mailing list:
5800 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5801 From: "Chris Hallinan" <clh@net1plus.com>
5802 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5805 Correct me if I'm wrong, folks, but the way I understand it
5806 is this: Using DCACHE as initial RAM for Stack, etc, does not
5807 require any physical RAM backing up the cache. The cleverness
5808 is that the cache is being used as a temporary supply of
5809 necessary storage before the SDRAM controller is setup. It's
5810 beyond the scope of this list to explain the details, but you
5811 can see how this works by studying the cache architecture and
5812 operation in the architecture and processor-specific manuals.
5814 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5815 is another option for the system designer to use as an
5816 initial stack/RAM area prior to SDRAM being available. Either
5817 option should work for you. Using CS 4 should be fine if your
5818 board designers haven't used it for something that would
5819 cause you grief during the initial boot! It is frequently not
5822 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5823 with your processor/board/system design. The default value
5824 you will find in any recent u-boot distribution in
5825 walnut.h should work for you. I'd set it to a value larger
5826 than your SDRAM module. If you have a 64MB SDRAM module, set
5827 it above 400_0000. Just make sure your board has no resources
5828 that are supposed to respond to that address! That code in
5829 start.S has been around a while and should work as is when
5830 you get the config right.
5835 It is essential to remember this, since it has some impact on the C
5836 code for the initialization procedures:
5838 * Initialized global data (data segment) is read-only. Do not attempt
5841 * Do not use any uninitialized global data (or implicitely initialized
5842 as zero data - BSS segment) at all - this is undefined, initiali-
5843 zation is performed later (when relocating to RAM).
5845 * Stack space is very limited. Avoid big data buffers or things like
5848 Having only the stack as writable memory limits means we cannot use
5849 normal global data to share information beween the code. But it
5850 turned out that the implementation of U-Boot can be greatly
5851 simplified by making a global data structure (gd_t) available to all
5852 functions. We could pass a pointer to this data as argument to _all_
5853 functions, but this would bloat the code. Instead we use a feature of
5854 the GCC compiler (Global Register Variables) to share the data: we
5855 place a pointer (gd) to the global data into a register which we
5856 reserve for this purpose.
5858 When choosing a register for such a purpose we are restricted by the
5859 relevant (E)ABI specifications for the current architecture, and by
5860 GCC's implementation.
5862 For PowerPC, the following registers have specific use:
5864 R2: reserved for system use
5865 R3-R4: parameter passing and return values
5866 R5-R10: parameter passing
5867 R13: small data area pointer
5871 (U-Boot also uses R12 as internal GOT pointer. r12
5872 is a volatile register so r12 needs to be reset when
5873 going back and forth between asm and C)
5875 ==> U-Boot will use R2 to hold a pointer to the global data
5877 Note: on PPC, we could use a static initializer (since the
5878 address of the global data structure is known at compile time),
5879 but it turned out that reserving a register results in somewhat
5880 smaller code - although the code savings are not that big (on
5881 average for all boards 752 bytes for the whole U-Boot image,
5882 624 text + 127 data).
5884 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5885 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5887 ==> U-Boot will use P3 to hold a pointer to the global data
5889 On ARM, the following registers are used:
5891 R0: function argument word/integer result
5892 R1-R3: function argument word
5893 R9: platform specific
5894 R10: stack limit (used only if stack checking is enabled)
5895 R11: argument (frame) pointer
5896 R12: temporary workspace
5899 R15: program counter
5901 ==> U-Boot will use R9 to hold a pointer to the global data
5903 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5905 On Nios II, the ABI is documented here:
5906 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5908 ==> U-Boot will use gp to hold a pointer to the global data
5910 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5911 to access small data sections, so gp is free.
5913 On NDS32, the following registers are used:
5915 R0-R1: argument/return
5917 R15: temporary register for assembler
5918 R16: trampoline register
5919 R28: frame pointer (FP)
5920 R29: global pointer (GP)
5921 R30: link register (LP)
5922 R31: stack pointer (SP)
5923 PC: program counter (PC)
5925 ==> U-Boot will use R10 to hold a pointer to the global data
5927 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5928 or current versions of GCC may "optimize" the code too much.
5933 U-Boot runs in system state and uses physical addresses, i.e. the
5934 MMU is not used either for address mapping nor for memory protection.
5936 The available memory is mapped to fixed addresses using the memory
5937 controller. In this process, a contiguous block is formed for each
5938 memory type (Flash, SDRAM, SRAM), even when it consists of several
5939 physical memory banks.
5941 U-Boot is installed in the first 128 kB of the first Flash bank (on
5942 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5943 booting and sizing and initializing DRAM, the code relocates itself
5944 to the upper end of DRAM. Immediately below the U-Boot code some
5945 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5946 configuration setting]. Below that, a structure with global Board
5947 Info data is placed, followed by the stack (growing downward).
5949 Additionally, some exception handler code is copied to the low 8 kB
5950 of DRAM (0x00000000 ... 0x00001FFF).
5952 So a typical memory configuration with 16 MB of DRAM could look like
5955 0x0000 0000 Exception Vector code
5958 0x0000 2000 Free for Application Use
5964 0x00FB FF20 Monitor Stack (Growing downward)
5965 0x00FB FFAC Board Info Data and permanent copy of global data
5966 0x00FC 0000 Malloc Arena
5969 0x00FE 0000 RAM Copy of Monitor Code
5970 ... eventually: LCD or video framebuffer
5971 ... eventually: pRAM (Protected RAM - unchanged by reset)
5972 0x00FF FFFF [End of RAM]
5975 System Initialization:
5976 ----------------------
5978 In the reset configuration, U-Boot starts at the reset entry point
5979 (on most PowerPC systems at address 0x00000100). Because of the reset
5980 configuration for CS0# this is a mirror of the onboard Flash memory.
5981 To be able to re-map memory U-Boot then jumps to its link address.
5982 To be able to implement the initialization code in C, a (small!)
5983 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5984 which provide such a feature like MPC8xx or MPC8260), or in a locked
5985 part of the data cache. After that, U-Boot initializes the CPU core,
5986 the caches and the SIU.
5988 Next, all (potentially) available memory banks are mapped using a
5989 preliminary mapping. For example, we put them on 512 MB boundaries
5990 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5991 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5992 programmed for SDRAM access. Using the temporary configuration, a
5993 simple memory test is run that determines the size of the SDRAM
5996 When there is more than one SDRAM bank, and the banks are of
5997 different size, the largest is mapped first. For equal size, the first
5998 bank (CS2#) is mapped first. The first mapping is always for address
5999 0x00000000, with any additional banks following immediately to create
6000 contiguous memory starting from 0.
6002 Then, the monitor installs itself at the upper end of the SDRAM area
6003 and allocates memory for use by malloc() and for the global Board
6004 Info data; also, the exception vector code is copied to the low RAM
6005 pages, and the final stack is set up.
6007 Only after this relocation will you have a "normal" C environment;
6008 until that you are restricted in several ways, mostly because you are
6009 running from ROM, and because the code will have to be relocated to a
6013 U-Boot Porting Guide:
6014 ----------------------
6016 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6020 int main(int argc, char *argv[])
6022 sighandler_t no_more_time;
6024 signal(SIGALRM, no_more_time);
6025 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6027 if (available_money > available_manpower) {
6028 Pay consultant to port U-Boot;
6032 Download latest U-Boot source;
6034 Subscribe to u-boot mailing list;
6037 email("Hi, I am new to U-Boot, how do I get started?");
6040 Read the README file in the top level directory;
6041 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6042 Read applicable doc/*.README;
6043 Read the source, Luke;
6044 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6047 if (available_money > toLocalCurrency ($2500))
6050 Add a lot of aggravation and time;
6052 if (a similar board exists) { /* hopefully... */
6053 cp -a board/<similar> board/<myboard>
6054 cp include/configs/<similar>.h include/configs/<myboard>.h
6056 Create your own board support subdirectory;
6057 Create your own board include/configs/<myboard>.h file;
6059 Edit new board/<myboard> files
6060 Edit new include/configs/<myboard>.h
6065 Add / modify source code;
6069 email("Hi, I am having problems...");
6071 Send patch file to the U-Boot email list;
6072 if (reasonable critiques)
6073 Incorporate improvements from email list code review;
6075 Defend code as written;
6081 void no_more_time (int sig)
6090 All contributions to U-Boot should conform to the Linux kernel
6091 coding style; see the file "Documentation/CodingStyle" and the script
6092 "scripts/Lindent" in your Linux kernel source directory.
6094 Source files originating from a different project (for example the
6095 MTD subsystem) are generally exempt from these guidelines and are not
6096 reformated to ease subsequent migration to newer versions of those
6099 Please note that U-Boot is implemented in C (and to some small parts in
6100 Assembler); no C++ is used, so please do not use C++ style comments (//)
6103 Please also stick to the following formatting rules:
6104 - remove any trailing white space
6105 - use TAB characters for indentation and vertical alignment, not spaces
6106 - make sure NOT to use DOS '\r\n' line feeds
6107 - do not add more than 2 consecutive empty lines to source files
6108 - do not add trailing empty lines to source files
6110 Submissions which do not conform to the standards may be returned
6111 with a request to reformat the changes.
6117 Since the number of patches for U-Boot is growing, we need to
6118 establish some rules. Submissions which do not conform to these rules
6119 may be rejected, even when they contain important and valuable stuff.
6121 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6123 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6124 see http://lists.denx.de/mailman/listinfo/u-boot
6126 When you send a patch, please include the following information with
6129 * For bug fixes: a description of the bug and how your patch fixes
6130 this bug. Please try to include a way of demonstrating that the
6131 patch actually fixes something.
6133 * For new features: a description of the feature and your
6136 * A CHANGELOG entry as plaintext (separate from the patch)
6138 * For major contributions, your entry to the CREDITS file
6140 * When you add support for a new board, don't forget to add a
6141 maintainer e-mail address to the boards.cfg file, too.
6143 * If your patch adds new configuration options, don't forget to
6144 document these in the README file.
6146 * The patch itself. If you are using git (which is *strongly*
6147 recommended) you can easily generate the patch using the
6148 "git format-patch". If you then use "git send-email" to send it to
6149 the U-Boot mailing list, you will avoid most of the common problems
6150 with some other mail clients.
6152 If you cannot use git, use "diff -purN OLD NEW". If your version of
6153 diff does not support these options, then get the latest version of
6156 The current directory when running this command shall be the parent
6157 directory of the U-Boot source tree (i. e. please make sure that
6158 your patch includes sufficient directory information for the
6161 We prefer patches as plain text. MIME attachments are discouraged,
6162 and compressed attachments must not be used.
6164 * If one logical set of modifications affects or creates several
6165 files, all these changes shall be submitted in a SINGLE patch file.
6167 * Changesets that contain different, unrelated modifications shall be
6168 submitted as SEPARATE patches, one patch per changeset.
6173 * Before sending the patch, run the MAKEALL script on your patched
6174 source tree and make sure that no errors or warnings are reported
6175 for any of the boards.
6177 * Keep your modifications to the necessary minimum: A patch
6178 containing several unrelated changes or arbitrary reformats will be
6179 returned with a request to re-formatting / split it.
6181 * If you modify existing code, make sure that your new code does not
6182 add to the memory footprint of the code ;-) Small is beautiful!
6183 When adding new features, these should compile conditionally only
6184 (using #ifdef), and the resulting code with the new feature
6185 disabled must not need more memory than the old code without your
6188 * Remember that there is a size limit of 100 kB per message on the
6189 u-boot mailing list. Bigger patches will be moderated. If they are
6190 reasonable and not too big, they will be acknowledged. But patches
6191 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob