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
1538 Enable the generic MMC driver
1540 CONFIG_SUPPORT_EMMC_BOOT
1541 Enable some additional features of the eMMC boot partitions.
1543 CONFIG_SUPPORT_EMMC_RPMB
1544 Enable the commands for reading, writing and programming the
1545 key for the Replay Protection Memory Block partition in eMMC.
1547 - USB Device Firmware Update (DFU) class support:
1549 This enables the USB portion of the DFU USB class
1552 This enables the command "dfu" which is used to have
1553 U-Boot create a DFU class device via USB. This command
1554 requires that the "dfu_alt_info" environment variable be
1555 set and define the alt settings to expose to the host.
1558 This enables support for exposing (e)MMC devices via DFU.
1561 This enables support for exposing NAND devices via DFU.
1564 This enables support for exposing RAM via DFU.
1565 Note: DFU spec refer to non-volatile memory usage, but
1566 allow usages beyond the scope of spec - here RAM usage,
1567 one that would help mostly the developer.
1569 CONFIG_SYS_DFU_DATA_BUF_SIZE
1570 Dfu transfer uses a buffer before writing data to the
1571 raw storage device. Make the size (in bytes) of this buffer
1572 configurable. The size of this buffer is also configurable
1573 through the "dfu_bufsiz" environment variable.
1575 CONFIG_SYS_DFU_MAX_FILE_SIZE
1576 When updating files rather than the raw storage device,
1577 we use a static buffer to copy the file into and then write
1578 the buffer once we've been given the whole file. Define
1579 this to the maximum filesize (in bytes) for the buffer.
1580 Default is 4 MiB if undefined.
1582 DFU_DEFAULT_POLL_TIMEOUT
1583 Poll timeout [ms], is the timeout a device can send to the
1584 host. The host must wait for this timeout before sending
1585 a subsequent DFU_GET_STATUS request to the device.
1587 DFU_MANIFEST_POLL_TIMEOUT
1588 Poll timeout [ms], which the device sends to the host when
1589 entering dfuMANIFEST state. Host waits this timeout, before
1590 sending again an USB request to the device.
1592 - USB Device Android Fastboot support:
1594 This enables the command "fastboot" which enables the Android
1595 fastboot mode for the platform's USB device. Fastboot is a USB
1596 protocol for downloading images, flashing and device control
1597 used on Android devices.
1598 See doc/README.android-fastboot for more information.
1600 CONFIG_ANDROID_BOOT_IMAGE
1601 This enables support for booting images which use the Android
1602 image format header.
1604 CONFIG_USB_FASTBOOT_BUF_ADDR
1605 The fastboot protocol requires a large memory buffer for
1606 downloads. Define this to the starting RAM address to use for
1609 CONFIG_USB_FASTBOOT_BUF_SIZE
1610 The fastboot protocol requires a large memory buffer for
1611 downloads. This buffer should be as large as possible for a
1612 platform. Define this to the size available RAM for fastboot.
1614 - Journaling Flash filesystem support:
1615 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1616 CONFIG_JFFS2_NAND_DEV
1617 Define these for a default partition on a NAND device
1619 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1620 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1621 Define these for a default partition on a NOR device
1623 CONFIG_SYS_JFFS_CUSTOM_PART
1624 Define this to create an own partition. You have to provide a
1625 function struct part_info* jffs2_part_info(int part_num)
1627 If you define only one JFFS2 partition you may also want to
1628 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1629 to disable the command chpart. This is the default when you
1630 have not defined a custom partition
1632 - FAT(File Allocation Table) filesystem write function support:
1635 Define this to enable support for saving memory data as a
1636 file in FAT formatted partition.
1638 This will also enable the command "fatwrite" enabling the
1639 user to write files to FAT.
1641 CBFS (Coreboot Filesystem) support
1644 Define this to enable support for reading from a Coreboot
1645 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1651 Define this to enable standard (PC-Style) keyboard
1655 Standard PC keyboard driver with US (is default) and
1656 GERMAN key layout (switch via environment 'keymap=de') support.
1657 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1658 for cfb_console. Supports cursor blinking.
1661 Enables a Chrome OS keyboard using the CROS_EC interface.
1662 This uses CROS_EC to communicate with a second microcontroller
1663 which provides key scans on request.
1668 Define this to enable video support (for output to
1671 CONFIG_VIDEO_CT69000
1673 Enable Chips & Technologies 69000 Video chip
1675 CONFIG_VIDEO_SMI_LYNXEM
1676 Enable Silicon Motion SMI 712/710/810 Video chip. The
1677 video output is selected via environment 'videoout'
1678 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1681 For the CT69000 and SMI_LYNXEM drivers, videomode is
1682 selected via environment 'videomode'. Two different ways
1684 - "videomode=num" 'num' is a standard LiLo mode numbers.
1685 Following standard modes are supported (* is default):
1687 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1688 -------------+---------------------------------------------
1689 8 bits | 0x301* 0x303 0x305 0x161 0x307
1690 15 bits | 0x310 0x313 0x316 0x162 0x319
1691 16 bits | 0x311 0x314 0x317 0x163 0x31A
1692 24 bits | 0x312 0x315 0x318 ? 0x31B
1693 -------------+---------------------------------------------
1694 (i.e. setenv videomode 317; saveenv; reset;)
1696 - "videomode=bootargs" all the video parameters are parsed
1697 from the bootargs. (See drivers/video/videomodes.c)
1700 CONFIG_VIDEO_SED13806
1701 Enable Epson SED13806 driver. This driver supports 8bpp
1702 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1703 or CONFIG_VIDEO_SED13806_16BPP
1706 Enable the Freescale DIU video driver. Reference boards for
1707 SOCs that have a DIU should define this macro to enable DIU
1708 support, and should also define these other macros:
1714 CONFIG_VIDEO_SW_CURSOR
1715 CONFIG_VGA_AS_SINGLE_DEVICE
1717 CONFIG_VIDEO_BMP_LOGO
1719 The DIU driver will look for the 'video-mode' environment
1720 variable, and if defined, enable the DIU as a console during
1721 boot. See the documentation file README.video for a
1722 description of this variable.
1726 Enable the VGA video / BIOS for x86. The alternative if you
1727 are using coreboot is to use the coreboot frame buffer
1734 Define this to enable a custom keyboard support.
1735 This simply calls drv_keyboard_init() which must be
1736 defined in your board-specific files.
1737 The only board using this so far is RBC823.
1739 - LCD Support: CONFIG_LCD
1741 Define this to enable LCD support (for output to LCD
1742 display); also select one of the supported displays
1743 by defining one of these:
1747 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1749 CONFIG_NEC_NL6448AC33:
1751 NEC NL6448AC33-18. Active, color, single scan.
1753 CONFIG_NEC_NL6448BC20
1755 NEC NL6448BC20-08. 6.5", 640x480.
1756 Active, color, single scan.
1758 CONFIG_NEC_NL6448BC33_54
1760 NEC NL6448BC33-54. 10.4", 640x480.
1761 Active, color, single scan.
1765 Sharp 320x240. Active, color, single scan.
1766 It isn't 16x9, and I am not sure what it is.
1768 CONFIG_SHARP_LQ64D341
1770 Sharp LQ64D341 display, 640x480.
1771 Active, color, single scan.
1775 HLD1045 display, 640x480.
1776 Active, color, single scan.
1780 Optrex CBL50840-2 NF-FW 99 22 M5
1782 Hitachi LMG6912RPFC-00T
1786 320x240. Black & white.
1788 Normally display is black on white background; define
1789 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1791 CONFIG_LCD_ALIGNMENT
1793 Normally the LCD is page-aligned (tyically 4KB). If this is
1794 defined then the LCD will be aligned to this value instead.
1795 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1796 here, since it is cheaper to change data cache settings on
1797 a per-section basis.
1799 CONFIG_CONSOLE_SCROLL_LINES
1801 When the console need to be scrolled, this is the number of
1802 lines to scroll by. It defaults to 1. Increasing this makes
1803 the console jump but can help speed up operation when scrolling
1808 Support drawing of RLE8-compressed bitmaps on the LCD.
1812 Enables an 'i2c edid' command which can read EDID
1813 information over I2C from an attached LCD display.
1815 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1817 If this option is set, the environment is checked for
1818 a variable "splashimage". If found, the usual display
1819 of logo, copyright and system information on the LCD
1820 is suppressed and the BMP image at the address
1821 specified in "splashimage" is loaded instead. The
1822 console is redirected to the "nulldev", too. This
1823 allows for a "silent" boot where a splash screen is
1824 loaded very quickly after power-on.
1826 CONFIG_SPLASHIMAGE_GUARD
1828 If this option is set, then U-Boot will prevent the environment
1829 variable "splashimage" from being set to a problematic address
1830 (see README.displaying-bmps).
1831 This option is useful for targets where, due to alignment
1832 restrictions, an improperly aligned BMP image will cause a data
1833 abort. If you think you will not have problems with unaligned
1834 accesses (for example because your toolchain prevents them)
1835 there is no need to set this option.
1837 CONFIG_SPLASH_SCREEN_ALIGN
1839 If this option is set the splash image can be freely positioned
1840 on the screen. Environment variable "splashpos" specifies the
1841 position as "x,y". If a positive number is given it is used as
1842 number of pixel from left/top. If a negative number is given it
1843 is used as number of pixel from right/bottom. You can also
1844 specify 'm' for centering the image.
1847 setenv splashpos m,m
1848 => image at center of screen
1850 setenv splashpos 30,20
1851 => image at x = 30 and y = 20
1853 setenv splashpos -10,m
1854 => vertically centered image
1855 at x = dspWidth - bmpWidth - 9
1857 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1859 If this option is set, additionally to standard BMP
1860 images, gzipped BMP images can be displayed via the
1861 splashscreen support or the bmp command.
1863 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1865 If this option is set, 8-bit RLE compressed BMP images
1866 can be displayed via the splashscreen support or the
1869 - Do compresssing for memory range:
1872 If this option is set, it would use zlib deflate method
1873 to compress the specified memory at its best effort.
1875 - Compression support:
1878 Enabled by default to support gzip compressed images.
1882 If this option is set, support for bzip2 compressed
1883 images is included. If not, only uncompressed and gzip
1884 compressed images are supported.
1886 NOTE: the bzip2 algorithm requires a lot of RAM, so
1887 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1892 If this option is set, support for lzma compressed
1895 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1896 requires an amount of dynamic memory that is given by the
1899 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1901 Where lc and lp stand for, respectively, Literal context bits
1902 and Literal pos bits.
1904 This value is upper-bounded by 14MB in the worst case. Anyway,
1905 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1906 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1907 a very small buffer.
1909 Use the lzmainfo tool to determinate the lc and lp values and
1910 then calculate the amount of needed dynamic memory (ensuring
1911 the appropriate CONFIG_SYS_MALLOC_LEN value).
1915 If this option is set, support for LZO compressed images
1921 The address of PHY on MII bus.
1923 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1925 The clock frequency of the MII bus
1929 If this option is set, support for speed/duplex
1930 detection of gigabit PHY is included.
1932 CONFIG_PHY_RESET_DELAY
1934 Some PHY like Intel LXT971A need extra delay after
1935 reset before any MII register access is possible.
1936 For such PHY, set this option to the usec delay
1937 required. (minimum 300usec for LXT971A)
1939 CONFIG_PHY_CMD_DELAY (ppc4xx)
1941 Some PHY like Intel LXT971A need extra delay after
1942 command issued before MII status register can be read
1952 Define a default value for Ethernet address to use
1953 for the respective Ethernet interface, in case this
1954 is not determined automatically.
1959 Define a default value for the IP address to use for
1960 the default Ethernet interface, in case this is not
1961 determined through e.g. bootp.
1962 (Environment variable "ipaddr")
1964 - Server IP address:
1967 Defines a default value for the IP address of a TFTP
1968 server to contact when using the "tftboot" command.
1969 (Environment variable "serverip")
1971 CONFIG_KEEP_SERVERADDR
1973 Keeps the server's MAC address, in the env 'serveraddr'
1974 for passing to bootargs (like Linux's netconsole option)
1976 - Gateway IP address:
1979 Defines a default value for the IP address of the
1980 default router where packets to other networks are
1982 (Environment variable "gatewayip")
1987 Defines a default value for the subnet mask (or
1988 routing prefix) which is used to determine if an IP
1989 address belongs to the local subnet or needs to be
1990 forwarded through a router.
1991 (Environment variable "netmask")
1993 - Multicast TFTP Mode:
1996 Defines whether you want to support multicast TFTP as per
1997 rfc-2090; for example to work with atftp. Lets lots of targets
1998 tftp down the same boot image concurrently. Note: the Ethernet
1999 driver in use must provide a function: mcast() to join/leave a
2002 - BOOTP Recovery Mode:
2003 CONFIG_BOOTP_RANDOM_DELAY
2005 If you have many targets in a network that try to
2006 boot using BOOTP, you may want to avoid that all
2007 systems send out BOOTP requests at precisely the same
2008 moment (which would happen for instance at recovery
2009 from a power failure, when all systems will try to
2010 boot, thus flooding the BOOTP server. Defining
2011 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2012 inserted before sending out BOOTP requests. The
2013 following delays are inserted then:
2015 1st BOOTP request: delay 0 ... 1 sec
2016 2nd BOOTP request: delay 0 ... 2 sec
2017 3rd BOOTP request: delay 0 ... 4 sec
2019 BOOTP requests: delay 0 ... 8 sec
2021 - DHCP Advanced Options:
2022 You can fine tune the DHCP functionality by defining
2023 CONFIG_BOOTP_* symbols:
2025 CONFIG_BOOTP_SUBNETMASK
2026 CONFIG_BOOTP_GATEWAY
2027 CONFIG_BOOTP_HOSTNAME
2028 CONFIG_BOOTP_NISDOMAIN
2029 CONFIG_BOOTP_BOOTPATH
2030 CONFIG_BOOTP_BOOTFILESIZE
2033 CONFIG_BOOTP_SEND_HOSTNAME
2034 CONFIG_BOOTP_NTPSERVER
2035 CONFIG_BOOTP_TIMEOFFSET
2036 CONFIG_BOOTP_VENDOREX
2037 CONFIG_BOOTP_MAY_FAIL
2039 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2040 environment variable, not the BOOTP server.
2042 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2043 after the configured retry count, the call will fail
2044 instead of starting over. This can be used to fail over
2045 to Link-local IP address configuration if the DHCP server
2048 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2049 serverip from a DHCP server, it is possible that more
2050 than one DNS serverip is offered to the client.
2051 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2052 serverip will be stored in the additional environment
2053 variable "dnsip2". The first DNS serverip is always
2054 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2057 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2058 to do a dynamic update of a DNS server. To do this, they
2059 need the hostname of the DHCP requester.
2060 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2061 of the "hostname" environment variable is passed as
2062 option 12 to the DHCP server.
2064 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2066 A 32bit value in microseconds for a delay between
2067 receiving a "DHCP Offer" and sending the "DHCP Request".
2068 This fixes a problem with certain DHCP servers that don't
2069 respond 100% of the time to a "DHCP request". E.g. On an
2070 AT91RM9200 processor running at 180MHz, this delay needed
2071 to be *at least* 15,000 usec before a Windows Server 2003
2072 DHCP server would reply 100% of the time. I recommend at
2073 least 50,000 usec to be safe. The alternative is to hope
2074 that one of the retries will be successful but note that
2075 the DHCP timeout and retry process takes a longer than
2078 - Link-local IP address negotiation:
2079 Negotiate with other link-local clients on the local network
2080 for an address that doesn't require explicit configuration.
2081 This is especially useful if a DHCP server cannot be guaranteed
2082 to exist in all environments that the device must operate.
2084 See doc/README.link-local for more information.
2087 CONFIG_CDP_DEVICE_ID
2089 The device id used in CDP trigger frames.
2091 CONFIG_CDP_DEVICE_ID_PREFIX
2093 A two character string which is prefixed to the MAC address
2098 A printf format string which contains the ascii name of
2099 the port. Normally is set to "eth%d" which sets
2100 eth0 for the first Ethernet, eth1 for the second etc.
2102 CONFIG_CDP_CAPABILITIES
2104 A 32bit integer which indicates the device capabilities;
2105 0x00000010 for a normal host which does not forwards.
2109 An ascii string containing the version of the software.
2113 An ascii string containing the name of the platform.
2117 A 32bit integer sent on the trigger.
2119 CONFIG_CDP_POWER_CONSUMPTION
2121 A 16bit integer containing the power consumption of the
2122 device in .1 of milliwatts.
2124 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2126 A byte containing the id of the VLAN.
2128 - Status LED: CONFIG_STATUS_LED
2130 Several configurations allow to display the current
2131 status using a LED. For instance, the LED will blink
2132 fast while running U-Boot code, stop blinking as
2133 soon as a reply to a BOOTP request was received, and
2134 start blinking slow once the Linux kernel is running
2135 (supported by a status LED driver in the Linux
2136 kernel). Defining CONFIG_STATUS_LED enables this
2142 The status LED can be connected to a GPIO pin.
2143 In such cases, the gpio_led driver can be used as a
2144 status LED backend implementation. Define CONFIG_GPIO_LED
2145 to include the gpio_led driver in the U-Boot binary.
2147 CONFIG_GPIO_LED_INVERTED_TABLE
2148 Some GPIO connected LEDs may have inverted polarity in which
2149 case the GPIO high value corresponds to LED off state and
2150 GPIO low value corresponds to LED on state.
2151 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2152 with a list of GPIO LEDs that have inverted polarity.
2154 - CAN Support: CONFIG_CAN_DRIVER
2156 Defining CONFIG_CAN_DRIVER enables CAN driver support
2157 on those systems that support this (optional)
2158 feature, like the TQM8xxL modules.
2160 - I2C Support: CONFIG_SYS_I2C
2162 This enable the NEW i2c subsystem, and will allow you to use
2163 i2c commands at the u-boot command line (as long as you set
2164 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2165 based realtime clock chips or other i2c devices. See
2166 common/cmd_i2c.c for a description of the command line
2169 ported i2c driver to the new framework:
2170 - drivers/i2c/soft_i2c.c:
2171 - activate first bus with CONFIG_SYS_I2C_SOFT define
2172 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2173 for defining speed and slave address
2174 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2175 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2176 for defining speed and slave address
2177 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2178 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2179 for defining speed and slave address
2180 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2181 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2182 for defining speed and slave address
2184 - drivers/i2c/fsl_i2c.c:
2185 - activate i2c driver with CONFIG_SYS_I2C_FSL
2186 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2187 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2188 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2190 - If your board supports a second fsl i2c bus, define
2191 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2192 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2193 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2196 - drivers/i2c/tegra_i2c.c:
2197 - activate this driver with CONFIG_SYS_I2C_TEGRA
2198 - This driver adds 4 i2c buses with a fix speed from
2199 100000 and the slave addr 0!
2201 - drivers/i2c/ppc4xx_i2c.c
2202 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2203 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2204 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2206 - drivers/i2c/i2c_mxc.c
2207 - activate this driver with CONFIG_SYS_I2C_MXC
2208 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2209 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2210 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2211 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2212 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2213 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2214 If thoses defines are not set, default value is 100000
2215 for speed, and 0 for slave.
2217 - drivers/i2c/rcar_i2c.c:
2218 - activate this driver with CONFIG_SYS_I2C_RCAR
2219 - This driver adds 4 i2c buses
2221 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2222 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2223 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2224 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2225 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2226 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2227 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2228 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2229 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2231 - drivers/i2c/sh_i2c.c:
2232 - activate this driver with CONFIG_SYS_I2C_SH
2233 - This driver adds from 2 to 5 i2c buses
2235 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2236 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2237 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2238 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2239 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2240 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2241 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2242 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2243 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2244 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2245 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2246 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2247 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2249 - drivers/i2c/omap24xx_i2c.c
2250 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2251 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2252 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2253 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2254 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2255 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2256 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2257 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2258 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2259 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2260 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2262 - drivers/i2c/zynq_i2c.c
2263 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2264 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2265 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2267 - drivers/i2c/s3c24x0_i2c.c:
2268 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2269 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2270 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2271 with a fix speed from 100000 and the slave addr 0!
2275 CONFIG_SYS_NUM_I2C_BUSES
2276 Hold the number of i2c busses you want to use. If you
2277 don't use/have i2c muxes on your i2c bus, this
2278 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2281 CONFIG_SYS_I2C_DIRECT_BUS
2282 define this, if you don't use i2c muxes on your hardware.
2283 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2286 CONFIG_SYS_I2C_MAX_HOPS
2287 define how many muxes are maximal consecutively connected
2288 on one i2c bus. If you not use i2c muxes, omit this
2291 CONFIG_SYS_I2C_BUSES
2292 hold a list of busses you want to use, only used if
2293 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2294 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2295 CONFIG_SYS_NUM_I2C_BUSES = 9:
2297 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2298 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2299 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2300 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2301 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2302 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2303 {1, {I2C_NULL_HOP}}, \
2304 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2305 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2309 bus 0 on adapter 0 without a mux
2310 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2311 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2312 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2313 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2314 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2315 bus 6 on adapter 1 without a mux
2316 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2317 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2319 If you do not have i2c muxes on your board, omit this define.
2321 - Legacy I2C Support: CONFIG_HARD_I2C
2323 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2324 provides the following compelling advantages:
2326 - more than one i2c adapter is usable
2327 - approved multibus support
2328 - better i2c mux support
2330 ** Please consider updating your I2C driver now. **
2332 These enable legacy I2C serial bus commands. Defining
2333 CONFIG_HARD_I2C will include the appropriate I2C driver
2334 for the selected CPU.
2336 This will allow you to use i2c commands at the u-boot
2337 command line (as long as you set CONFIG_CMD_I2C in
2338 CONFIG_COMMANDS) and communicate with i2c based realtime
2339 clock chips. See common/cmd_i2c.c for a description of the
2340 command line interface.
2342 CONFIG_HARD_I2C selects a hardware I2C controller.
2344 There are several other quantities that must also be
2345 defined when you define CONFIG_HARD_I2C.
2347 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2348 to be the frequency (in Hz) at which you wish your i2c bus
2349 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2350 the CPU's i2c node address).
2352 Now, the u-boot i2c code for the mpc8xx
2353 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2354 and so its address should therefore be cleared to 0 (See,
2355 eg, MPC823e User's Manual p.16-473). So, set
2356 CONFIG_SYS_I2C_SLAVE to 0.
2358 CONFIG_SYS_I2C_INIT_MPC5XXX
2360 When a board is reset during an i2c bus transfer
2361 chips might think that the current transfer is still
2362 in progress. Reset the slave devices by sending start
2363 commands until the slave device responds.
2365 That's all that's required for CONFIG_HARD_I2C.
2367 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2368 then the following macros need to be defined (examples are
2369 from include/configs/lwmon.h):
2373 (Optional). Any commands necessary to enable the I2C
2374 controller or configure ports.
2376 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2380 (Only for MPC8260 CPU). The I/O port to use (the code
2381 assumes both bits are on the same port). Valid values
2382 are 0..3 for ports A..D.
2386 The code necessary to make the I2C data line active
2387 (driven). If the data line is open collector, this
2390 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2394 The code necessary to make the I2C data line tri-stated
2395 (inactive). If the data line is open collector, this
2398 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2402 Code that returns true if the I2C data line is high,
2405 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2409 If <bit> is true, sets the I2C data line high. If it
2410 is false, it clears it (low).
2412 eg: #define I2C_SDA(bit) \
2413 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2414 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2418 If <bit> is true, sets the I2C clock line high. If it
2419 is false, it clears it (low).
2421 eg: #define I2C_SCL(bit) \
2422 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2423 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2427 This delay is invoked four times per clock cycle so this
2428 controls the rate of data transfer. The data rate thus
2429 is 1 / (I2C_DELAY * 4). Often defined to be something
2432 #define I2C_DELAY udelay(2)
2434 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2436 If your arch supports the generic GPIO framework (asm/gpio.h),
2437 then you may alternatively define the two GPIOs that are to be
2438 used as SCL / SDA. Any of the previous I2C_xxx macros will
2439 have GPIO-based defaults assigned to them as appropriate.
2441 You should define these to the GPIO value as given directly to
2442 the generic GPIO functions.
2444 CONFIG_SYS_I2C_INIT_BOARD
2446 When a board is reset during an i2c bus transfer
2447 chips might think that the current transfer is still
2448 in progress. On some boards it is possible to access
2449 the i2c SCLK line directly, either by using the
2450 processor pin as a GPIO or by having a second pin
2451 connected to the bus. If this option is defined a
2452 custom i2c_init_board() routine in boards/xxx/board.c
2453 is run early in the boot sequence.
2455 CONFIG_SYS_I2C_BOARD_LATE_INIT
2457 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2458 defined a custom i2c_board_late_init() routine in
2459 boards/xxx/board.c is run AFTER the operations in i2c_init()
2460 is completed. This callpoint can be used to unreset i2c bus
2461 using CPU i2c controller register accesses for CPUs whose i2c
2462 controller provide such a method. It is called at the end of
2463 i2c_init() to allow i2c_init operations to setup the i2c bus
2464 controller on the CPU (e.g. setting bus speed & slave address).
2466 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2468 This option enables configuration of bi_iic_fast[] flags
2469 in u-boot bd_info structure based on u-boot environment
2470 variable "i2cfast". (see also i2cfast)
2472 CONFIG_I2C_MULTI_BUS
2474 This option allows the use of multiple I2C buses, each of which
2475 must have a controller. At any point in time, only one bus is
2476 active. To switch to a different bus, use the 'i2c dev' command.
2477 Note that bus numbering is zero-based.
2479 CONFIG_SYS_I2C_NOPROBES
2481 This option specifies a list of I2C devices that will be skipped
2482 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2483 is set, specify a list of bus-device pairs. Otherwise, specify
2484 a 1D array of device addresses
2487 #undef CONFIG_I2C_MULTI_BUS
2488 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2490 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2492 #define CONFIG_I2C_MULTI_BUS
2493 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2495 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2497 CONFIG_SYS_SPD_BUS_NUM
2499 If defined, then this indicates the I2C bus number for DDR SPD.
2500 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2502 CONFIG_SYS_RTC_BUS_NUM
2504 If defined, then this indicates the I2C bus number for the RTC.
2505 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2507 CONFIG_SYS_DTT_BUS_NUM
2509 If defined, then this indicates the I2C bus number for the DTT.
2510 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2512 CONFIG_SYS_I2C_DTT_ADDR:
2514 If defined, specifies the I2C address of the DTT device.
2515 If not defined, then U-Boot uses predefined value for
2516 specified DTT device.
2518 CONFIG_SOFT_I2C_READ_REPEATED_START
2520 defining this will force the i2c_read() function in
2521 the soft_i2c driver to perform an I2C repeated start
2522 between writing the address pointer and reading the
2523 data. If this define is omitted the default behaviour
2524 of doing a stop-start sequence will be used. Most I2C
2525 devices can use either method, but some require one or
2528 - SPI Support: CONFIG_SPI
2530 Enables SPI driver (so far only tested with
2531 SPI EEPROM, also an instance works with Crystal A/D and
2532 D/As on the SACSng board)
2536 Enables the driver for SPI controller on SuperH. Currently
2537 only SH7757 is supported.
2541 Enables extended (16-bit) SPI EEPROM addressing.
2542 (symmetrical to CONFIG_I2C_X)
2546 Enables a software (bit-bang) SPI driver rather than
2547 using hardware support. This is a general purpose
2548 driver that only requires three general I/O port pins
2549 (two outputs, one input) to function. If this is
2550 defined, the board configuration must define several
2551 SPI configuration items (port pins to use, etc). For
2552 an example, see include/configs/sacsng.h.
2556 Enables a hardware SPI driver for general-purpose reads
2557 and writes. As with CONFIG_SOFT_SPI, the board configuration
2558 must define a list of chip-select function pointers.
2559 Currently supported on some MPC8xxx processors. For an
2560 example, see include/configs/mpc8349emds.h.
2564 Enables the driver for the SPI controllers on i.MX and MXC
2565 SoCs. Currently i.MX31/35/51 are supported.
2567 - FPGA Support: CONFIG_FPGA
2569 Enables FPGA subsystem.
2571 CONFIG_FPGA_<vendor>
2573 Enables support for specific chip vendors.
2576 CONFIG_FPGA_<family>
2578 Enables support for FPGA family.
2579 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2583 Specify the number of FPGA devices to support.
2585 CONFIG_CMD_FPGA_LOADMK
2587 Enable support for fpga loadmk command
2589 CONFIG_CMD_FPGA_LOADP
2591 Enable support for fpga loadp command - load partial bitstream
2593 CONFIG_CMD_FPGA_LOADBP
2595 Enable support for fpga loadbp command - load partial bitstream
2598 CONFIG_SYS_FPGA_PROG_FEEDBACK
2600 Enable printing of hash marks during FPGA configuration.
2602 CONFIG_SYS_FPGA_CHECK_BUSY
2604 Enable checks on FPGA configuration interface busy
2605 status by the configuration function. This option
2606 will require a board or device specific function to
2611 If defined, a function that provides delays in the FPGA
2612 configuration driver.
2614 CONFIG_SYS_FPGA_CHECK_CTRLC
2615 Allow Control-C to interrupt FPGA configuration
2617 CONFIG_SYS_FPGA_CHECK_ERROR
2619 Check for configuration errors during FPGA bitfile
2620 loading. For example, abort during Virtex II
2621 configuration if the INIT_B line goes low (which
2622 indicated a CRC error).
2624 CONFIG_SYS_FPGA_WAIT_INIT
2626 Maximum time to wait for the INIT_B line to deassert
2627 after PROB_B has been deasserted during a Virtex II
2628 FPGA configuration sequence. The default time is 500
2631 CONFIG_SYS_FPGA_WAIT_BUSY
2633 Maximum time to wait for BUSY to deassert during
2634 Virtex II FPGA configuration. The default is 5 ms.
2636 CONFIG_SYS_FPGA_WAIT_CONFIG
2638 Time to wait after FPGA configuration. The default is
2641 - Configuration Management:
2644 If defined, this string will be added to the U-Boot
2645 version information (U_BOOT_VERSION)
2647 - Vendor Parameter Protection:
2649 U-Boot considers the values of the environment
2650 variables "serial#" (Board Serial Number) and
2651 "ethaddr" (Ethernet Address) to be parameters that
2652 are set once by the board vendor / manufacturer, and
2653 protects these variables from casual modification by
2654 the user. Once set, these variables are read-only,
2655 and write or delete attempts are rejected. You can
2656 change this behaviour:
2658 If CONFIG_ENV_OVERWRITE is #defined in your config
2659 file, the write protection for vendor parameters is
2660 completely disabled. Anybody can change or delete
2663 Alternatively, if you #define _both_ CONFIG_ETHADDR
2664 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2665 Ethernet address is installed in the environment,
2666 which can be changed exactly ONCE by the user. [The
2667 serial# is unaffected by this, i. e. it remains
2670 The same can be accomplished in a more flexible way
2671 for any variable by configuring the type of access
2672 to allow for those variables in the ".flags" variable
2673 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2678 Define this variable to enable the reservation of
2679 "protected RAM", i. e. RAM which is not overwritten
2680 by U-Boot. Define CONFIG_PRAM to hold the number of
2681 kB you want to reserve for pRAM. You can overwrite
2682 this default value by defining an environment
2683 variable "pram" to the number of kB you want to
2684 reserve. Note that the board info structure will
2685 still show the full amount of RAM. If pRAM is
2686 reserved, a new environment variable "mem" will
2687 automatically be defined to hold the amount of
2688 remaining RAM in a form that can be passed as boot
2689 argument to Linux, for instance like that:
2691 setenv bootargs ... mem=\${mem}
2694 This way you can tell Linux not to use this memory,
2695 either, which results in a memory region that will
2696 not be affected by reboots.
2698 *WARNING* If your board configuration uses automatic
2699 detection of the RAM size, you must make sure that
2700 this memory test is non-destructive. So far, the
2701 following board configurations are known to be
2704 IVMS8, IVML24, SPD8xx, TQM8xxL,
2705 HERMES, IP860, RPXlite, LWMON,
2708 - Access to physical memory region (> 4GB)
2709 Some basic support is provided for operations on memory not
2710 normally accessible to U-Boot - e.g. some architectures
2711 support access to more than 4GB of memory on 32-bit
2712 machines using physical address extension or similar.
2713 Define CONFIG_PHYSMEM to access this basic support, which
2714 currently only supports clearing the memory.
2719 Define this variable to stop the system in case of a
2720 fatal error, so that you have to reset it manually.
2721 This is probably NOT a good idea for an embedded
2722 system where you want the system to reboot
2723 automatically as fast as possible, but it may be
2724 useful during development since you can try to debug
2725 the conditions that lead to the situation.
2727 CONFIG_NET_RETRY_COUNT
2729 This variable defines the number of retries for
2730 network operations like ARP, RARP, TFTP, or BOOTP
2731 before giving up the operation. If not defined, a
2732 default value of 5 is used.
2736 Timeout waiting for an ARP reply in milliseconds.
2740 Timeout in milliseconds used in NFS protocol.
2741 If you encounter "ERROR: Cannot umount" in nfs command,
2742 try longer timeout such as
2743 #define CONFIG_NFS_TIMEOUT 10000UL
2745 - Command Interpreter:
2746 CONFIG_AUTO_COMPLETE
2748 Enable auto completion of commands using TAB.
2750 Note that this feature has NOT been implemented yet
2751 for the "hush" shell.
2754 CONFIG_SYS_HUSH_PARSER
2756 Define this variable to enable the "hush" shell (from
2757 Busybox) as command line interpreter, thus enabling
2758 powerful command line syntax like
2759 if...then...else...fi conditionals or `&&' and '||'
2760 constructs ("shell scripts").
2762 If undefined, you get the old, much simpler behaviour
2763 with a somewhat smaller memory footprint.
2766 CONFIG_SYS_PROMPT_HUSH_PS2
2768 This defines the secondary prompt string, which is
2769 printed when the command interpreter needs more input
2770 to complete a command. Usually "> ".
2774 In the current implementation, the local variables
2775 space and global environment variables space are
2776 separated. Local variables are those you define by
2777 simply typing `name=value'. To access a local
2778 variable later on, you have write `$name' or
2779 `${name}'; to execute the contents of a variable
2780 directly type `$name' at the command prompt.
2782 Global environment variables are those you use
2783 setenv/printenv to work with. To run a command stored
2784 in such a variable, you need to use the run command,
2785 and you must not use the '$' sign to access them.
2787 To store commands and special characters in a
2788 variable, please use double quotation marks
2789 surrounding the whole text of the variable, instead
2790 of the backslashes before semicolons and special
2793 - Commandline Editing and History:
2794 CONFIG_CMDLINE_EDITING
2796 Enable editing and History functions for interactive
2797 commandline input operations
2799 - Default Environment:
2800 CONFIG_EXTRA_ENV_SETTINGS
2802 Define this to contain any number of null terminated
2803 strings (variable = value pairs) that will be part of
2804 the default environment compiled into the boot image.
2806 For example, place something like this in your
2807 board's config file:
2809 #define CONFIG_EXTRA_ENV_SETTINGS \
2813 Warning: This method is based on knowledge about the
2814 internal format how the environment is stored by the
2815 U-Boot code. This is NOT an official, exported
2816 interface! Although it is unlikely that this format
2817 will change soon, there is no guarantee either.
2818 You better know what you are doing here.
2820 Note: overly (ab)use of the default environment is
2821 discouraged. Make sure to check other ways to preset
2822 the environment like the "source" command or the
2825 CONFIG_ENV_VARS_UBOOT_CONFIG
2827 Define this in order to add variables describing the
2828 U-Boot build configuration to the default environment.
2829 These will be named arch, cpu, board, vendor, and soc.
2831 Enabling this option will cause the following to be defined:
2839 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2841 Define this in order to add variables describing certain
2842 run-time determined information about the hardware to the
2843 environment. These will be named board_name, board_rev.
2845 CONFIG_DELAY_ENVIRONMENT
2847 Normally the environment is loaded when the board is
2848 intialised so that it is available to U-Boot. This inhibits
2849 that so that the environment is not available until
2850 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2851 this is instead controlled by the value of
2852 /config/load-environment.
2854 - DataFlash Support:
2855 CONFIG_HAS_DATAFLASH
2857 Defining this option enables DataFlash features and
2858 allows to read/write in Dataflash via the standard
2861 - Serial Flash support
2864 Defining this option enables SPI flash commands
2865 'sf probe/read/write/erase/update'.
2867 Usage requires an initial 'probe' to define the serial
2868 flash parameters, followed by read/write/erase/update
2871 The following defaults may be provided by the platform
2872 to handle the common case when only a single serial
2873 flash is present on the system.
2875 CONFIG_SF_DEFAULT_BUS Bus identifier
2876 CONFIG_SF_DEFAULT_CS Chip-select
2877 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2878 CONFIG_SF_DEFAULT_SPEED in Hz
2882 Define this option to include a destructive SPI flash
2885 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2887 Define this option to use the Bank addr/Extended addr
2888 support on SPI flashes which has size > 16Mbytes.
2890 CONFIG_SF_DUAL_FLASH Dual flash memories
2892 Define this option to use dual flash support where two flash
2893 memories can be connected with a given cs line.
2894 currently Xilinx Zynq qspi support these type of connections.
2896 - SystemACE Support:
2899 Adding this option adds support for Xilinx SystemACE
2900 chips attached via some sort of local bus. The address
2901 of the chip must also be defined in the
2902 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2904 #define CONFIG_SYSTEMACE
2905 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2907 When SystemACE support is added, the "ace" device type
2908 becomes available to the fat commands, i.e. fatls.
2910 - TFTP Fixed UDP Port:
2913 If this is defined, the environment variable tftpsrcp
2914 is used to supply the TFTP UDP source port value.
2915 If tftpsrcp isn't defined, the normal pseudo-random port
2916 number generator is used.
2918 Also, the environment variable tftpdstp is used to supply
2919 the TFTP UDP destination port value. If tftpdstp isn't
2920 defined, the normal port 69 is used.
2922 The purpose for tftpsrcp is to allow a TFTP server to
2923 blindly start the TFTP transfer using the pre-configured
2924 target IP address and UDP port. This has the effect of
2925 "punching through" the (Windows XP) firewall, allowing
2926 the remainder of the TFTP transfer to proceed normally.
2927 A better solution is to properly configure the firewall,
2928 but sometimes that is not allowed.
2933 This enables a generic 'hash' command which can produce
2934 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2938 Enable the hash verify command (hash -v). This adds to code
2941 CONFIG_SHA1 - support SHA1 hashing
2942 CONFIG_SHA256 - support SHA256 hashing
2944 Note: There is also a sha1sum command, which should perhaps
2945 be deprecated in favour of 'hash sha1'.
2947 - Freescale i.MX specific commands:
2948 CONFIG_CMD_HDMIDETECT
2949 This enables 'hdmidet' command which returns true if an
2950 HDMI monitor is detected. This command is i.MX 6 specific.
2953 This enables the 'bmode' (bootmode) command for forcing
2954 a boot from specific media.
2956 This is useful for forcing the ROM's usb downloader to
2957 activate upon a watchdog reset which is nice when iterating
2958 on U-Boot. Using the reset button or running bmode normal
2959 will set it back to normal. This command currently
2960 supports i.MX53 and i.MX6.
2965 This enables the RSA algorithm used for FIT image verification
2966 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2968 The signing part is build into mkimage regardless of this
2971 - bootcount support:
2972 CONFIG_BOOTCOUNT_LIMIT
2974 This enables the bootcounter support, see:
2975 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2978 enable special bootcounter support on at91sam9xe based boards.
2980 enable special bootcounter support on blackfin based boards.
2982 enable special bootcounter support on da850 based boards.
2983 CONFIG_BOOTCOUNT_RAM
2984 enable support for the bootcounter in RAM
2985 CONFIG_BOOTCOUNT_I2C
2986 enable support for the bootcounter on an i2c (like RTC) device.
2987 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2988 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2990 CONFIG_BOOTCOUNT_ALEN = address len
2992 - Show boot progress:
2993 CONFIG_SHOW_BOOT_PROGRESS
2995 Defining this option allows to add some board-
2996 specific code (calling a user-provided function
2997 "show_boot_progress(int)") that enables you to show
2998 the system's boot progress on some display (for
2999 example, some LED's) on your board. At the moment,
3000 the following checkpoints are implemented:
3002 - Detailed boot stage timing
3004 Define this option to get detailed timing of each stage
3005 of the boot process.
3007 CONFIG_BOOTSTAGE_USER_COUNT
3008 This is the number of available user bootstage records.
3009 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3010 a new ID will be allocated from this stash. If you exceed
3011 the limit, recording will stop.
3013 CONFIG_BOOTSTAGE_REPORT
3014 Define this to print a report before boot, similar to this:
3016 Timer summary in microseconds:
3019 3,575,678 3,575,678 board_init_f start
3020 3,575,695 17 arch_cpu_init A9
3021 3,575,777 82 arch_cpu_init done
3022 3,659,598 83,821 board_init_r start
3023 3,910,375 250,777 main_loop
3024 29,916,167 26,005,792 bootm_start
3025 30,361,327 445,160 start_kernel
3027 CONFIG_CMD_BOOTSTAGE
3028 Add a 'bootstage' command which supports printing a report
3029 and un/stashing of bootstage data.
3031 CONFIG_BOOTSTAGE_FDT
3032 Stash the bootstage information in the FDT. A root 'bootstage'
3033 node is created with each bootstage id as a child. Each child
3034 has a 'name' property and either 'mark' containing the
3035 mark time in microsecond, or 'accum' containing the
3036 accumulated time for that bootstage id in microseconds.
3041 name = "board_init_f";
3050 Code in the Linux kernel can find this in /proc/devicetree.
3052 Legacy uImage format:
3055 1 common/cmd_bootm.c before attempting to boot an image
3056 -1 common/cmd_bootm.c Image header has bad magic number
3057 2 common/cmd_bootm.c Image header has correct magic number
3058 -2 common/cmd_bootm.c Image header has bad checksum
3059 3 common/cmd_bootm.c Image header has correct checksum
3060 -3 common/cmd_bootm.c Image data has bad checksum
3061 4 common/cmd_bootm.c Image data has correct checksum
3062 -4 common/cmd_bootm.c Image is for unsupported architecture
3063 5 common/cmd_bootm.c Architecture check OK
3064 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3065 6 common/cmd_bootm.c Image Type check OK
3066 -6 common/cmd_bootm.c gunzip uncompression error
3067 -7 common/cmd_bootm.c Unimplemented compression type
3068 7 common/cmd_bootm.c Uncompression OK
3069 8 common/cmd_bootm.c No uncompress/copy overwrite error
3070 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3072 9 common/image.c Start initial ramdisk verification
3073 -10 common/image.c Ramdisk header has bad magic number
3074 -11 common/image.c Ramdisk header has bad checksum
3075 10 common/image.c Ramdisk header is OK
3076 -12 common/image.c Ramdisk data has bad checksum
3077 11 common/image.c Ramdisk data has correct checksum
3078 12 common/image.c Ramdisk verification complete, start loading
3079 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3080 13 common/image.c Start multifile image verification
3081 14 common/image.c No initial ramdisk, no multifile, continue.
3083 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3085 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3086 -31 post/post.c POST test failed, detected by post_output_backlog()
3087 -32 post/post.c POST test failed, detected by post_run_single()
3089 34 common/cmd_doc.c before loading a Image from a DOC device
3090 -35 common/cmd_doc.c Bad usage of "doc" command
3091 35 common/cmd_doc.c correct usage of "doc" command
3092 -36 common/cmd_doc.c No boot device
3093 36 common/cmd_doc.c correct boot device
3094 -37 common/cmd_doc.c Unknown Chip ID on boot device
3095 37 common/cmd_doc.c correct chip ID found, device available
3096 -38 common/cmd_doc.c Read Error on boot device
3097 38 common/cmd_doc.c reading Image header from DOC device OK
3098 -39 common/cmd_doc.c Image header has bad magic number
3099 39 common/cmd_doc.c Image header has correct magic number
3100 -40 common/cmd_doc.c Error reading Image from DOC device
3101 40 common/cmd_doc.c Image header has correct magic number
3102 41 common/cmd_ide.c before loading a Image from a IDE device
3103 -42 common/cmd_ide.c Bad usage of "ide" command
3104 42 common/cmd_ide.c correct usage of "ide" command
3105 -43 common/cmd_ide.c No boot device
3106 43 common/cmd_ide.c boot device found
3107 -44 common/cmd_ide.c Device not available
3108 44 common/cmd_ide.c Device available
3109 -45 common/cmd_ide.c wrong partition selected
3110 45 common/cmd_ide.c partition selected
3111 -46 common/cmd_ide.c Unknown partition table
3112 46 common/cmd_ide.c valid partition table found
3113 -47 common/cmd_ide.c Invalid partition type
3114 47 common/cmd_ide.c correct partition type
3115 -48 common/cmd_ide.c Error reading Image Header on boot device
3116 48 common/cmd_ide.c reading Image Header from IDE device OK
3117 -49 common/cmd_ide.c Image header has bad magic number
3118 49 common/cmd_ide.c Image header has correct magic number
3119 -50 common/cmd_ide.c Image header has bad checksum
3120 50 common/cmd_ide.c Image header has correct checksum
3121 -51 common/cmd_ide.c Error reading Image from IDE device
3122 51 common/cmd_ide.c reading Image from IDE device OK
3123 52 common/cmd_nand.c before loading a Image from a NAND device
3124 -53 common/cmd_nand.c Bad usage of "nand" command
3125 53 common/cmd_nand.c correct usage of "nand" command
3126 -54 common/cmd_nand.c No boot device
3127 54 common/cmd_nand.c boot device found
3128 -55 common/cmd_nand.c Unknown Chip ID on boot device
3129 55 common/cmd_nand.c correct chip ID found, device available
3130 -56 common/cmd_nand.c Error reading Image Header on boot device
3131 56 common/cmd_nand.c reading Image Header from NAND device OK
3132 -57 common/cmd_nand.c Image header has bad magic number
3133 57 common/cmd_nand.c Image header has correct magic number
3134 -58 common/cmd_nand.c Error reading Image from NAND device
3135 58 common/cmd_nand.c reading Image from NAND device OK
3137 -60 common/env_common.c Environment has a bad CRC, using default
3139 64 net/eth.c starting with Ethernet configuration.
3140 -64 net/eth.c no Ethernet found.
3141 65 net/eth.c Ethernet found.
3143 -80 common/cmd_net.c usage wrong
3144 80 common/cmd_net.c before calling NetLoop()
3145 -81 common/cmd_net.c some error in NetLoop() occurred
3146 81 common/cmd_net.c NetLoop() back without error
3147 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3148 82 common/cmd_net.c trying automatic boot
3149 83 common/cmd_net.c running "source" command
3150 -83 common/cmd_net.c some error in automatic boot or "source" command
3151 84 common/cmd_net.c end without errors
3156 100 common/cmd_bootm.c Kernel FIT Image has correct format
3157 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3158 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3159 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3160 102 common/cmd_bootm.c Kernel unit name specified
3161 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3162 103 common/cmd_bootm.c Found configuration node
3163 104 common/cmd_bootm.c Got kernel subimage node offset
3164 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3165 105 common/cmd_bootm.c Kernel subimage hash verification OK
3166 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3167 106 common/cmd_bootm.c Architecture check OK
3168 -106 common/cmd_bootm.c Kernel subimage has wrong type
3169 107 common/cmd_bootm.c Kernel subimage type OK
3170 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3171 108 common/cmd_bootm.c Got kernel subimage data/size
3172 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3173 -109 common/cmd_bootm.c Can't get kernel subimage type
3174 -110 common/cmd_bootm.c Can't get kernel subimage comp
3175 -111 common/cmd_bootm.c Can't get kernel subimage os
3176 -112 common/cmd_bootm.c Can't get kernel subimage load address
3177 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3179 120 common/image.c Start initial ramdisk verification
3180 -120 common/image.c Ramdisk FIT image has incorrect format
3181 121 common/image.c Ramdisk FIT image has correct format
3182 122 common/image.c No ramdisk subimage unit name, using configuration
3183 -122 common/image.c Can't get configuration for ramdisk subimage
3184 123 common/image.c Ramdisk unit name specified
3185 -124 common/image.c Can't get ramdisk subimage node offset
3186 125 common/image.c Got ramdisk subimage node offset
3187 -125 common/image.c Ramdisk subimage hash verification failed
3188 126 common/image.c Ramdisk subimage hash verification OK
3189 -126 common/image.c Ramdisk subimage for unsupported architecture
3190 127 common/image.c Architecture check OK
3191 -127 common/image.c Can't get ramdisk subimage data/size
3192 128 common/image.c Got ramdisk subimage data/size
3193 129 common/image.c Can't get ramdisk load address
3194 -129 common/image.c Got ramdisk load address
3196 -130 common/cmd_doc.c Incorrect FIT image format
3197 131 common/cmd_doc.c FIT image format OK
3199 -140 common/cmd_ide.c Incorrect FIT image format
3200 141 common/cmd_ide.c FIT image format OK
3202 -150 common/cmd_nand.c Incorrect FIT image format
3203 151 common/cmd_nand.c FIT image format OK
3205 - FIT image support:
3207 Enable support for the FIT uImage format.
3209 CONFIG_FIT_BEST_MATCH
3210 When no configuration is explicitly selected, default to the
3211 one whose fdt's compatibility field best matches that of
3212 U-Boot itself. A match is considered "best" if it matches the
3213 most specific compatibility entry of U-Boot's fdt's root node.
3214 The order of entries in the configuration's fdt is ignored.
3216 CONFIG_FIT_SIGNATURE
3217 This option enables signature verification of FIT uImages,
3218 using a hash signed and verified using RSA. See
3219 doc/uImage.FIT/signature.txt for more details.
3221 - Standalone program support:
3222 CONFIG_STANDALONE_LOAD_ADDR
3224 This option defines a board specific value for the
3225 address where standalone program gets loaded, thus
3226 overwriting the architecture dependent default
3229 - Frame Buffer Address:
3232 Define CONFIG_FB_ADDR if you want to use specific
3233 address for frame buffer. This is typically the case
3234 when using a graphics controller has separate video
3235 memory. U-Boot will then place the frame buffer at
3236 the given address instead of dynamically reserving it
3237 in system RAM by calling lcd_setmem(), which grabs
3238 the memory for the frame buffer depending on the
3239 configured panel size.
3241 Please see board_init_f function.
3243 - Automatic software updates via TFTP server
3245 CONFIG_UPDATE_TFTP_CNT_MAX
3246 CONFIG_UPDATE_TFTP_MSEC_MAX
3248 These options enable and control the auto-update feature;
3249 for a more detailed description refer to doc/README.update.
3251 - MTD Support (mtdparts command, UBI support)
3254 Adds the MTD device infrastructure from the Linux kernel.
3255 Needed for mtdparts command support.
3257 CONFIG_MTD_PARTITIONS
3259 Adds the MTD partitioning infrastructure from the Linux
3260 kernel. Needed for UBI support.
3265 Adds commands for interacting with MTD partitions formatted
3266 with the UBI flash translation layer
3268 Requires also defining CONFIG_RBTREE
3270 CONFIG_UBI_SILENCE_MSG
3272 Make the verbose messages from UBI stop printing. This leaves
3273 warnings and errors enabled.
3278 Adds commands for interacting with UBI volumes formatted as
3279 UBIFS. UBIFS is read-only in u-boot.
3281 Requires UBI support as well as CONFIG_LZO
3283 CONFIG_UBIFS_SILENCE_MSG
3285 Make the verbose messages from UBIFS stop printing. This leaves
3286 warnings and errors enabled.
3290 Enable building of SPL globally.
3293 LDSCRIPT for linking the SPL binary.
3295 CONFIG_SPL_MAX_FOOTPRINT
3296 Maximum size in memory allocated to the SPL, BSS included.
3297 When defined, the linker checks that the actual memory
3298 used by SPL from _start to __bss_end does not exceed it.
3299 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3300 must not be both defined at the same time.
3303 Maximum size of the SPL image (text, data, rodata, and
3304 linker lists sections), BSS excluded.
3305 When defined, the linker checks that the actual size does
3308 CONFIG_SPL_TEXT_BASE
3309 TEXT_BASE for linking the SPL binary.
3311 CONFIG_SPL_RELOC_TEXT_BASE
3312 Address to relocate to. If unspecified, this is equal to
3313 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3315 CONFIG_SPL_BSS_START_ADDR
3316 Link address for the BSS within the SPL binary.
3318 CONFIG_SPL_BSS_MAX_SIZE
3319 Maximum size in memory allocated to the SPL BSS.
3320 When defined, the linker checks that the actual memory used
3321 by SPL from __bss_start to __bss_end does not exceed it.
3322 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3323 must not be both defined at the same time.
3326 Adress of the start of the stack SPL will use
3328 CONFIG_SPL_RELOC_STACK
3329 Adress of the start of the stack SPL will use after
3330 relocation. If unspecified, this is equal to
3333 CONFIG_SYS_SPL_MALLOC_START
3334 Starting address of the malloc pool used in SPL.
3336 CONFIG_SYS_SPL_MALLOC_SIZE
3337 The size of the malloc pool used in SPL.
3339 CONFIG_SPL_FRAMEWORK
3340 Enable the SPL framework under common/. This framework
3341 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3342 NAND loading of the Linux Kernel.
3345 Enable booting directly to an OS from SPL.
3346 See also: doc/README.falcon
3348 CONFIG_SPL_DISPLAY_PRINT
3349 For ARM, enable an optional function to print more information
3350 about the running system.
3352 CONFIG_SPL_INIT_MINIMAL
3353 Arch init code should be built for a very small image
3355 CONFIG_SPL_LIBCOMMON_SUPPORT
3356 Support for common/libcommon.o in SPL binary
3358 CONFIG_SPL_LIBDISK_SUPPORT
3359 Support for disk/libdisk.o in SPL binary
3361 CONFIG_SPL_I2C_SUPPORT
3362 Support for drivers/i2c/libi2c.o in SPL binary
3364 CONFIG_SPL_GPIO_SUPPORT
3365 Support for drivers/gpio/libgpio.o in SPL binary
3367 CONFIG_SPL_MMC_SUPPORT
3368 Support for drivers/mmc/libmmc.o in SPL binary
3370 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3371 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3372 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3373 Address, size and partition on the MMC to load U-Boot from
3374 when the MMC is being used in raw mode.
3376 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3377 Sector to load kernel uImage from when MMC is being
3378 used in raw mode (for Falcon mode)
3380 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3381 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3382 Sector and number of sectors to load kernel argument
3383 parameters from when MMC is being used in raw mode
3386 CONFIG_SPL_FAT_SUPPORT
3387 Support for fs/fat/libfat.o in SPL binary
3389 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3390 Filename to read to load U-Boot when reading from FAT
3392 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3393 Filename to read to load kernel uImage when reading
3394 from FAT (for Falcon mode)
3396 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3397 Filename to read to load kernel argument parameters
3398 when reading from FAT (for Falcon mode)
3400 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3401 Set this for NAND SPL on PPC mpc83xx targets, so that
3402 start.S waits for the rest of the SPL to load before
3403 continuing (the hardware starts execution after just
3404 loading the first page rather than the full 4K).
3406 CONFIG_SPL_SKIP_RELOCATE
3407 Avoid SPL relocation
3409 CONFIG_SPL_NAND_BASE
3410 Include nand_base.c in the SPL. Requires
3411 CONFIG_SPL_NAND_DRIVERS.
3413 CONFIG_SPL_NAND_DRIVERS
3414 SPL uses normal NAND drivers, not minimal drivers.
3417 Include standard software ECC in the SPL
3419 CONFIG_SPL_NAND_SIMPLE
3420 Support for NAND boot using simple NAND drivers that
3421 expose the cmd_ctrl() interface.
3423 CONFIG_SPL_MTD_SUPPORT
3424 Support for the MTD subsystem within SPL. Useful for
3425 environment on NAND support within SPL.
3427 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3428 Set for the SPL on PPC mpc8xxx targets, support for
3429 drivers/ddr/fsl/libddr.o in SPL binary.
3431 CONFIG_SPL_COMMON_INIT_DDR
3432 Set for common ddr init with serial presence detect in
3435 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3436 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3437 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3438 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3439 CONFIG_SYS_NAND_ECCBYTES
3440 Defines the size and behavior of the NAND that SPL uses
3443 CONFIG_SPL_NAND_BOOT
3444 Add support NAND boot
3446 CONFIG_SYS_NAND_U_BOOT_OFFS
3447 Location in NAND to read U-Boot from
3449 CONFIG_SYS_NAND_U_BOOT_DST
3450 Location in memory to load U-Boot to
3452 CONFIG_SYS_NAND_U_BOOT_SIZE
3453 Size of image to load
3455 CONFIG_SYS_NAND_U_BOOT_START
3456 Entry point in loaded image to jump to
3458 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3459 Define this if you need to first read the OOB and then the
3460 data. This is used for example on davinci plattforms.
3462 CONFIG_SPL_OMAP3_ID_NAND
3463 Support for an OMAP3-specific set of functions to return the
3464 ID and MFR of the first attached NAND chip, if present.
3466 CONFIG_SPL_SERIAL_SUPPORT
3467 Support for drivers/serial/libserial.o in SPL binary
3469 CONFIG_SPL_SPI_FLASH_SUPPORT
3470 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3472 CONFIG_SPL_SPI_SUPPORT
3473 Support for drivers/spi/libspi.o in SPL binary
3475 CONFIG_SPL_RAM_DEVICE
3476 Support for running image already present in ram, in SPL binary
3478 CONFIG_SPL_LIBGENERIC_SUPPORT
3479 Support for lib/libgeneric.o in SPL binary
3481 CONFIG_SPL_ENV_SUPPORT
3482 Support for the environment operating in SPL binary
3484 CONFIG_SPL_NET_SUPPORT
3485 Support for the net/libnet.o in SPL binary.
3486 It conflicts with SPL env from storage medium specified by
3487 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3490 Image offset to which the SPL should be padded before appending
3491 the SPL payload. By default, this is defined as
3492 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3493 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3494 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3497 Final target image containing SPL and payload. Some SPLs
3498 use an arch-specific makefile fragment instead, for
3499 example if more than one image needs to be produced.
3501 CONFIG_FIT_SPL_PRINT
3502 Printing information about a FIT image adds quite a bit of
3503 code to SPL. So this is normally disabled in SPL. Use this
3504 option to re-enable it. This will affect the output of the
3505 bootm command when booting a FIT image.
3509 Enable building of TPL globally.
3512 Image offset to which the TPL should be padded before appending
3513 the TPL payload. By default, this is defined as
3514 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3515 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3516 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3521 [so far only for SMDK2400 boards]
3523 - Modem support enable:
3524 CONFIG_MODEM_SUPPORT
3526 - RTS/CTS Flow control enable:
3529 - Modem debug support:
3530 CONFIG_MODEM_SUPPORT_DEBUG
3532 Enables debugging stuff (char screen[1024], dbg())
3533 for modem support. Useful only with BDI2000.
3535 - Interrupt support (PPC):
3537 There are common interrupt_init() and timer_interrupt()
3538 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3539 for CPU specific initialization. interrupt_init_cpu()
3540 should set decrementer_count to appropriate value. If
3541 CPU resets decrementer automatically after interrupt
3542 (ppc4xx) it should set decrementer_count to zero.
3543 timer_interrupt() calls timer_interrupt_cpu() for CPU
3544 specific handling. If board has watchdog / status_led
3545 / other_activity_monitor it works automatically from
3546 general timer_interrupt().
3550 In the target system modem support is enabled when a
3551 specific key (key combination) is pressed during
3552 power-on. Otherwise U-Boot will boot normally
3553 (autoboot). The key_pressed() function is called from
3554 board_init(). Currently key_pressed() is a dummy
3555 function, returning 1 and thus enabling modem
3558 If there are no modem init strings in the
3559 environment, U-Boot proceed to autoboot; the
3560 previous output (banner, info printfs) will be
3563 See also: doc/README.Modem
3565 Board initialization settings:
3566 ------------------------------
3568 During Initialization u-boot calls a number of board specific functions
3569 to allow the preparation of board specific prerequisites, e.g. pin setup
3570 before drivers are initialized. To enable these callbacks the
3571 following configuration macros have to be defined. Currently this is
3572 architecture specific, so please check arch/your_architecture/lib/board.c
3573 typically in board_init_f() and board_init_r().
3575 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3576 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3577 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3578 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3580 Configuration Settings:
3581 -----------------------
3583 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3584 Optionally it can be defined to support 64-bit memory commands.
3586 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3587 undefine this when you're short of memory.
3589 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3590 width of the commands listed in the 'help' command output.
3592 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3593 prompt for user input.
3595 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3597 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3599 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3601 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3602 the application (usually a Linux kernel) when it is
3605 - CONFIG_SYS_BAUDRATE_TABLE:
3606 List of legal baudrate settings for this board.
3608 - CONFIG_SYS_CONSOLE_INFO_QUIET
3609 Suppress display of console information at boot.
3611 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3612 If the board specific function
3613 extern int overwrite_console (void);
3614 returns 1, the stdin, stderr and stdout are switched to the
3615 serial port, else the settings in the environment are used.
3617 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3618 Enable the call to overwrite_console().
3620 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3621 Enable overwrite of previous console environment settings.
3623 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3624 Begin and End addresses of the area used by the
3627 - CONFIG_SYS_ALT_MEMTEST:
3628 Enable an alternate, more extensive memory test.
3630 - CONFIG_SYS_MEMTEST_SCRATCH:
3631 Scratch address used by the alternate memory test
3632 You only need to set this if address zero isn't writeable
3634 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3635 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3636 this specified memory area will get subtracted from the top
3637 (end) of RAM and won't get "touched" at all by U-Boot. By
3638 fixing up gd->ram_size the Linux kernel should gets passed
3639 the now "corrected" memory size and won't touch it either.
3640 This should work for arch/ppc and arch/powerpc. Only Linux
3641 board ports in arch/powerpc with bootwrapper support that
3642 recalculate the memory size from the SDRAM controller setup
3643 will have to get fixed in Linux additionally.
3645 This option can be used as a workaround for the 440EPx/GRx
3646 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3649 WARNING: Please make sure that this value is a multiple of
3650 the Linux page size (normally 4k). If this is not the case,
3651 then the end address of the Linux memory will be located at a
3652 non page size aligned address and this could cause major
3655 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3656 Enable temporary baudrate change while serial download
3658 - CONFIG_SYS_SDRAM_BASE:
3659 Physical start address of SDRAM. _Must_ be 0 here.
3661 - CONFIG_SYS_MBIO_BASE:
3662 Physical start address of Motherboard I/O (if using a
3665 - CONFIG_SYS_FLASH_BASE:
3666 Physical start address of Flash memory.
3668 - CONFIG_SYS_MONITOR_BASE:
3669 Physical start address of boot monitor code (set by
3670 make config files to be same as the text base address
3671 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3672 CONFIG_SYS_FLASH_BASE when booting from flash.
3674 - CONFIG_SYS_MONITOR_LEN:
3675 Size of memory reserved for monitor code, used to
3676 determine _at_compile_time_ (!) if the environment is
3677 embedded within the U-Boot image, or in a separate
3680 - CONFIG_SYS_MALLOC_LEN:
3681 Size of DRAM reserved for malloc() use.
3683 - CONFIG_SYS_BOOTM_LEN:
3684 Normally compressed uImages are limited to an
3685 uncompressed size of 8 MBytes. If this is not enough,
3686 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3687 to adjust this setting to your needs.
3689 - CONFIG_SYS_BOOTMAPSZ:
3690 Maximum size of memory mapped by the startup code of
3691 the Linux kernel; all data that must be processed by
3692 the Linux kernel (bd_info, boot arguments, FDT blob if
3693 used) must be put below this limit, unless "bootm_low"
3694 environment variable is defined and non-zero. In such case
3695 all data for the Linux kernel must be between "bootm_low"
3696 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3697 variable "bootm_mapsize" will override the value of
3698 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3699 then the value in "bootm_size" will be used instead.
3701 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3702 Enable initrd_high functionality. If defined then the
3703 initrd_high feature is enabled and the bootm ramdisk subcommand
3706 - CONFIG_SYS_BOOT_GET_CMDLINE:
3707 Enables allocating and saving kernel cmdline in space between
3708 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3710 - CONFIG_SYS_BOOT_GET_KBD:
3711 Enables allocating and saving a kernel copy of the bd_info in
3712 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3714 - CONFIG_SYS_MAX_FLASH_BANKS:
3715 Max number of Flash memory banks
3717 - CONFIG_SYS_MAX_FLASH_SECT:
3718 Max number of sectors on a Flash chip
3720 - CONFIG_SYS_FLASH_ERASE_TOUT:
3721 Timeout for Flash erase operations (in ms)
3723 - CONFIG_SYS_FLASH_WRITE_TOUT:
3724 Timeout for Flash write operations (in ms)
3726 - CONFIG_SYS_FLASH_LOCK_TOUT
3727 Timeout for Flash set sector lock bit operation (in ms)
3729 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3730 Timeout for Flash clear lock bits operation (in ms)
3732 - CONFIG_SYS_FLASH_PROTECTION
3733 If defined, hardware flash sectors protection is used
3734 instead of U-Boot software protection.
3736 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3738 Enable TFTP transfers directly to flash memory;
3739 without this option such a download has to be
3740 performed in two steps: (1) download to RAM, and (2)
3741 copy from RAM to flash.
3743 The two-step approach is usually more reliable, since
3744 you can check if the download worked before you erase
3745 the flash, but in some situations (when system RAM is
3746 too limited to allow for a temporary copy of the
3747 downloaded image) this option may be very useful.
3749 - CONFIG_SYS_FLASH_CFI:
3750 Define if the flash driver uses extra elements in the
3751 common flash structure for storing flash geometry.
3753 - CONFIG_FLASH_CFI_DRIVER
3754 This option also enables the building of the cfi_flash driver
3755 in the drivers directory
3757 - CONFIG_FLASH_CFI_MTD
3758 This option enables the building of the cfi_mtd driver
3759 in the drivers directory. The driver exports CFI flash
3762 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3763 Use buffered writes to flash.
3765 - CONFIG_FLASH_SPANSION_S29WS_N
3766 s29ws-n MirrorBit flash has non-standard addresses for buffered
3769 - CONFIG_SYS_FLASH_QUIET_TEST
3770 If this option is defined, the common CFI flash doesn't
3771 print it's warning upon not recognized FLASH banks. This
3772 is useful, if some of the configured banks are only
3773 optionally available.
3775 - CONFIG_FLASH_SHOW_PROGRESS
3776 If defined (must be an integer), print out countdown
3777 digits and dots. Recommended value: 45 (9..1) for 80
3778 column displays, 15 (3..1) for 40 column displays.
3780 - CONFIG_FLASH_VERIFY
3781 If defined, the content of the flash (destination) is compared
3782 against the source after the write operation. An error message
3783 will be printed when the contents are not identical.
3784 Please note that this option is useless in nearly all cases,
3785 since such flash programming errors usually are detected earlier
3786 while unprotecting/erasing/programming. Please only enable
3787 this option if you really know what you are doing.
3789 - CONFIG_SYS_RX_ETH_BUFFER:
3790 Defines the number of Ethernet receive buffers. On some
3791 Ethernet controllers it is recommended to set this value
3792 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3793 buffers can be full shortly after enabling the interface
3794 on high Ethernet traffic.
3795 Defaults to 4 if not defined.
3797 - CONFIG_ENV_MAX_ENTRIES
3799 Maximum number of entries in the hash table that is used
3800 internally to store the environment settings. The default
3801 setting is supposed to be generous and should work in most
3802 cases. This setting can be used to tune behaviour; see
3803 lib/hashtable.c for details.
3805 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3806 - CONFIG_ENV_FLAGS_LIST_STATIC
3807 Enable validation of the values given to environment variables when
3808 calling env set. Variables can be restricted to only decimal,
3809 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3810 the variables can also be restricted to IP address or MAC address.
3812 The format of the list is:
3813 type_attribute = [s|d|x|b|i|m]
3814 access_atribute = [a|r|o|c]
3815 attributes = type_attribute[access_atribute]
3816 entry = variable_name[:attributes]
3819 The type attributes are:
3820 s - String (default)
3823 b - Boolean ([1yYtT|0nNfF])
3827 The access attributes are:
3833 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3834 Define this to a list (string) to define the ".flags"
3835 envirnoment variable in the default or embedded environment.
3837 - CONFIG_ENV_FLAGS_LIST_STATIC
3838 Define this to a list (string) to define validation that
3839 should be done if an entry is not found in the ".flags"
3840 environment variable. To override a setting in the static
3841 list, simply add an entry for the same variable name to the
3844 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3845 If defined, don't allow the -f switch to env set override variable
3848 - CONFIG_SYS_GENERIC_BOARD
3849 This selects the architecture-generic board system instead of the
3850 architecture-specific board files. It is intended to move boards
3851 to this new framework over time. Defining this will disable the
3852 arch/foo/lib/board.c file and use common/board_f.c and
3853 common/board_r.c instead. To use this option your architecture
3854 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3855 its config.mk file). If you find problems enabling this option on
3856 your board please report the problem and send patches!
3858 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3859 This is set by OMAP boards for the max time that reset should
3860 be asserted. See doc/README.omap-reset-time for details on how
3861 the value can be calulated on a given board.
3863 The following definitions that deal with the placement and management
3864 of environment data (variable area); in general, we support the
3865 following configurations:
3867 - CONFIG_BUILD_ENVCRC:
3869 Builds up envcrc with the target environment so that external utils
3870 may easily extract it and embed it in final U-Boot images.
3872 - CONFIG_ENV_IS_IN_FLASH:
3874 Define this if the environment is in flash memory.
3876 a) The environment occupies one whole flash sector, which is
3877 "embedded" in the text segment with the U-Boot code. This
3878 happens usually with "bottom boot sector" or "top boot
3879 sector" type flash chips, which have several smaller
3880 sectors at the start or the end. For instance, such a
3881 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3882 such a case you would place the environment in one of the
3883 4 kB sectors - with U-Boot code before and after it. With
3884 "top boot sector" type flash chips, you would put the
3885 environment in one of the last sectors, leaving a gap
3886 between U-Boot and the environment.
3888 - CONFIG_ENV_OFFSET:
3890 Offset of environment data (variable area) to the
3891 beginning of flash memory; for instance, with bottom boot
3892 type flash chips the second sector can be used: the offset
3893 for this sector is given here.
3895 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3899 This is just another way to specify the start address of
3900 the flash sector containing the environment (instead of
3903 - CONFIG_ENV_SECT_SIZE:
3905 Size of the sector containing the environment.
3908 b) Sometimes flash chips have few, equal sized, BIG sectors.
3909 In such a case you don't want to spend a whole sector for
3914 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3915 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3916 of this flash sector for the environment. This saves
3917 memory for the RAM copy of the environment.
3919 It may also save flash memory if you decide to use this
3920 when your environment is "embedded" within U-Boot code,
3921 since then the remainder of the flash sector could be used
3922 for U-Boot code. It should be pointed out that this is
3923 STRONGLY DISCOURAGED from a robustness point of view:
3924 updating the environment in flash makes it always
3925 necessary to erase the WHOLE sector. If something goes
3926 wrong before the contents has been restored from a copy in
3927 RAM, your target system will be dead.
3929 - CONFIG_ENV_ADDR_REDUND
3930 CONFIG_ENV_SIZE_REDUND
3932 These settings describe a second storage area used to hold
3933 a redundant copy of the environment data, so that there is
3934 a valid backup copy in case there is a power failure during
3935 a "saveenv" operation.
3937 BE CAREFUL! Any changes to the flash layout, and some changes to the
3938 source code will make it necessary to adapt <board>/u-boot.lds*
3942 - CONFIG_ENV_IS_IN_NVRAM:
3944 Define this if you have some non-volatile memory device
3945 (NVRAM, battery buffered SRAM) which you want to use for the
3951 These two #defines are used to determine the memory area you
3952 want to use for environment. It is assumed that this memory
3953 can just be read and written to, without any special
3956 BE CAREFUL! The first access to the environment happens quite early
3957 in U-Boot initalization (when we try to get the setting of for the
3958 console baudrate). You *MUST* have mapped your NVRAM area then, or
3961 Please note that even with NVRAM we still use a copy of the
3962 environment in RAM: we could work on NVRAM directly, but we want to
3963 keep settings there always unmodified except somebody uses "saveenv"
3964 to save the current settings.
3967 - CONFIG_ENV_IS_IN_EEPROM:
3969 Use this if you have an EEPROM or similar serial access
3970 device and a driver for it.
3972 - CONFIG_ENV_OFFSET:
3975 These two #defines specify the offset and size of the
3976 environment area within the total memory of your EEPROM.
3978 - CONFIG_SYS_I2C_EEPROM_ADDR:
3979 If defined, specified the chip address of the EEPROM device.
3980 The default address is zero.
3982 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3983 If defined, the number of bits used to address bytes in a
3984 single page in the EEPROM device. A 64 byte page, for example
3985 would require six bits.
3987 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3988 If defined, the number of milliseconds to delay between
3989 page writes. The default is zero milliseconds.
3991 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3992 The length in bytes of the EEPROM memory array address. Note
3993 that this is NOT the chip address length!
3995 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3996 EEPROM chips that implement "address overflow" are ones
3997 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3998 address and the extra bits end up in the "chip address" bit
3999 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4002 Note that we consider the length of the address field to
4003 still be one byte because the extra address bits are hidden
4004 in the chip address.
4006 - CONFIG_SYS_EEPROM_SIZE:
4007 The size in bytes of the EEPROM device.
4009 - CONFIG_ENV_EEPROM_IS_ON_I2C
4010 define this, if you have I2C and SPI activated, and your
4011 EEPROM, which holds the environment, is on the I2C bus.
4013 - CONFIG_I2C_ENV_EEPROM_BUS
4014 if you have an Environment on an EEPROM reached over
4015 I2C muxes, you can define here, how to reach this
4016 EEPROM. For example:
4018 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4020 EEPROM which holds the environment, is reached over
4021 a pca9547 i2c mux with address 0x70, channel 3.
4023 - CONFIG_ENV_IS_IN_DATAFLASH:
4025 Define this if you have a DataFlash memory device which you
4026 want to use for the environment.
4028 - CONFIG_ENV_OFFSET:
4032 These three #defines specify the offset and size of the
4033 environment area within the total memory of your DataFlash placed
4034 at the specified address.
4036 - CONFIG_ENV_IS_IN_REMOTE:
4038 Define this if you have a remote memory space which you
4039 want to use for the local device's environment.
4044 These two #defines specify the address and size of the
4045 environment area within the remote memory space. The
4046 local device can get the environment from remote memory
4047 space by SRIO or PCIE links.
4049 BE CAREFUL! For some special cases, the local device can not use
4050 "saveenv" command. For example, the local device will get the
4051 environment stored in a remote NOR flash by SRIO or PCIE link,
4052 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4054 - CONFIG_ENV_IS_IN_NAND:
4056 Define this if you have a NAND device which you want to use
4057 for the environment.
4059 - CONFIG_ENV_OFFSET:
4062 These two #defines specify the offset and size of the environment
4063 area within the first NAND device. CONFIG_ENV_OFFSET must be
4064 aligned to an erase block boundary.
4066 - CONFIG_ENV_OFFSET_REDUND (optional):
4068 This setting describes a second storage area of CONFIG_ENV_SIZE
4069 size used to hold a redundant copy of the environment data, so
4070 that there is a valid backup copy in case there is a power failure
4071 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4072 aligned to an erase block boundary.
4074 - CONFIG_ENV_RANGE (optional):
4076 Specifies the length of the region in which the environment
4077 can be written. This should be a multiple of the NAND device's
4078 block size. Specifying a range with more erase blocks than
4079 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4080 the range to be avoided.
4082 - CONFIG_ENV_OFFSET_OOB (optional):
4084 Enables support for dynamically retrieving the offset of the
4085 environment from block zero's out-of-band data. The
4086 "nand env.oob" command can be used to record this offset.
4087 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4088 using CONFIG_ENV_OFFSET_OOB.
4090 - CONFIG_NAND_ENV_DST
4092 Defines address in RAM to which the nand_spl code should copy the
4093 environment. If redundant environment is used, it will be copied to
4094 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4096 - CONFIG_ENV_IS_IN_UBI:
4098 Define this if you have an UBI volume that you want to use for the
4099 environment. This has the benefit of wear-leveling the environment
4100 accesses, which is important on NAND.
4102 - CONFIG_ENV_UBI_PART:
4104 Define this to a string that is the mtd partition containing the UBI.
4106 - CONFIG_ENV_UBI_VOLUME:
4108 Define this to the name of the volume that you want to store the
4111 - CONFIG_ENV_UBI_VOLUME_REDUND:
4113 Define this to the name of another volume to store a second copy of
4114 the environment in. This will enable redundant environments in UBI.
4115 It is assumed that both volumes are in the same MTD partition.
4117 - CONFIG_UBI_SILENCE_MSG
4118 - CONFIG_UBIFS_SILENCE_MSG
4120 You will probably want to define these to avoid a really noisy system
4121 when storing the env in UBI.
4123 - CONFIG_ENV_IS_IN_MMC:
4125 Define this if you have an MMC device which you want to use for the
4128 - CONFIG_SYS_MMC_ENV_DEV:
4130 Specifies which MMC device the environment is stored in.
4132 - CONFIG_SYS_MMC_ENV_PART (optional):
4134 Specifies which MMC partition the environment is stored in. If not
4135 set, defaults to partition 0, the user area. Common values might be
4136 1 (first MMC boot partition), 2 (second MMC boot partition).
4138 - CONFIG_ENV_OFFSET:
4141 These two #defines specify the offset and size of the environment
4142 area within the specified MMC device.
4144 If offset is positive (the usual case), it is treated as relative to
4145 the start of the MMC partition. If offset is negative, it is treated
4146 as relative to the end of the MMC partition. This can be useful if
4147 your board may be fitted with different MMC devices, which have
4148 different sizes for the MMC partitions, and you always want the
4149 environment placed at the very end of the partition, to leave the
4150 maximum possible space before it, to store other data.
4152 These two values are in units of bytes, but must be aligned to an
4153 MMC sector boundary.
4155 - CONFIG_ENV_OFFSET_REDUND (optional):
4157 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4158 hold a redundant copy of the environment data. This provides a
4159 valid backup copy in case the other copy is corrupted, e.g. due
4160 to a power failure during a "saveenv" operation.
4162 This value may also be positive or negative; this is handled in the
4163 same way as CONFIG_ENV_OFFSET.
4165 This value is also in units of bytes, but must also be aligned to
4166 an MMC sector boundary.
4168 - CONFIG_ENV_SIZE_REDUND (optional):
4170 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4171 set. If this value is set, it must be set to the same value as
4174 - CONFIG_SYS_SPI_INIT_OFFSET
4176 Defines offset to the initial SPI buffer area in DPRAM. The
4177 area is used at an early stage (ROM part) if the environment
4178 is configured to reside in the SPI EEPROM: We need a 520 byte
4179 scratch DPRAM area. It is used between the two initialization
4180 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4181 to be a good choice since it makes it far enough from the
4182 start of the data area as well as from the stack pointer.
4184 Please note that the environment is read-only until the monitor
4185 has been relocated to RAM and a RAM copy of the environment has been
4186 created; also, when using EEPROM you will have to use getenv_f()
4187 until then to read environment variables.
4189 The environment is protected by a CRC32 checksum. Before the monitor
4190 is relocated into RAM, as a result of a bad CRC you will be working
4191 with the compiled-in default environment - *silently*!!! [This is
4192 necessary, because the first environment variable we need is the
4193 "baudrate" setting for the console - if we have a bad CRC, we don't
4194 have any device yet where we could complain.]
4196 Note: once the monitor has been relocated, then it will complain if
4197 the default environment is used; a new CRC is computed as soon as you
4198 use the "saveenv" command to store a valid environment.
4200 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4201 Echo the inverted Ethernet link state to the fault LED.
4203 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4204 also needs to be defined.
4206 - CONFIG_SYS_FAULT_MII_ADDR:
4207 MII address of the PHY to check for the Ethernet link state.
4209 - CONFIG_NS16550_MIN_FUNCTIONS:
4210 Define this if you desire to only have use of the NS16550_init
4211 and NS16550_putc functions for the serial driver located at
4212 drivers/serial/ns16550.c. This option is useful for saving
4213 space for already greatly restricted images, including but not
4214 limited to NAND_SPL configurations.
4216 - CONFIG_DISPLAY_BOARDINFO
4217 Display information about the board that U-Boot is running on
4218 when U-Boot starts up. The board function checkboard() is called
4221 - CONFIG_DISPLAY_BOARDINFO_LATE
4222 Similar to the previous option, but display this information
4223 later, once stdio is running and output goes to the LCD, if
4226 Low Level (hardware related) configuration options:
4227 ---------------------------------------------------
4229 - CONFIG_SYS_CACHELINE_SIZE:
4230 Cache Line Size of the CPU.
4232 - CONFIG_SYS_DEFAULT_IMMR:
4233 Default address of the IMMR after system reset.
4235 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4236 and RPXsuper) to be able to adjust the position of
4237 the IMMR register after a reset.
4239 - CONFIG_SYS_CCSRBAR_DEFAULT:
4240 Default (power-on reset) physical address of CCSR on Freescale
4243 - CONFIG_SYS_CCSRBAR:
4244 Virtual address of CCSR. On a 32-bit build, this is typically
4245 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4247 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4248 for cross-platform code that uses that macro instead.
4250 - CONFIG_SYS_CCSRBAR_PHYS:
4251 Physical address of CCSR. CCSR can be relocated to a new
4252 physical address, if desired. In this case, this macro should
4253 be set to that address. Otherwise, it should be set to the
4254 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4255 is typically relocated on 36-bit builds. It is recommended
4256 that this macro be defined via the _HIGH and _LOW macros:
4258 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4259 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4261 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4262 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4263 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4264 used in assembly code, so it must not contain typecasts or
4265 integer size suffixes (e.g. "ULL").
4267 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4268 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4269 used in assembly code, so it must not contain typecasts or
4270 integer size suffixes (e.g. "ULL").
4272 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4273 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4274 forced to a value that ensures that CCSR is not relocated.
4276 - Floppy Disk Support:
4277 CONFIG_SYS_FDC_DRIVE_NUMBER
4279 the default drive number (default value 0)
4281 CONFIG_SYS_ISA_IO_STRIDE
4283 defines the spacing between FDC chipset registers
4286 CONFIG_SYS_ISA_IO_OFFSET
4288 defines the offset of register from address. It
4289 depends on which part of the data bus is connected to
4290 the FDC chipset. (default value 0)
4292 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4293 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4296 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4297 fdc_hw_init() is called at the beginning of the FDC
4298 setup. fdc_hw_init() must be provided by the board
4299 source code. It is used to make hardware dependant
4303 Most IDE controllers were designed to be connected with PCI
4304 interface. Only few of them were designed for AHB interface.
4305 When software is doing ATA command and data transfer to
4306 IDE devices through IDE-AHB controller, some additional
4307 registers accessing to these kind of IDE-AHB controller
4310 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4311 DO NOT CHANGE unless you know exactly what you're
4312 doing! (11-4) [MPC8xx/82xx systems only]
4314 - CONFIG_SYS_INIT_RAM_ADDR:
4316 Start address of memory area that can be used for
4317 initial data and stack; please note that this must be
4318 writable memory that is working WITHOUT special
4319 initialization, i. e. you CANNOT use normal RAM which
4320 will become available only after programming the
4321 memory controller and running certain initialization
4324 U-Boot uses the following memory types:
4325 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4326 - MPC824X: data cache
4327 - PPC4xx: data cache
4329 - CONFIG_SYS_GBL_DATA_OFFSET:
4331 Offset of the initial data structure in the memory
4332 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4333 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4334 data is located at the end of the available space
4335 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4336 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4337 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4338 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4341 On the MPC824X (or other systems that use the data
4342 cache for initial memory) the address chosen for
4343 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4344 point to an otherwise UNUSED address space between
4345 the top of RAM and the start of the PCI space.
4347 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4349 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4351 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4353 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4355 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4357 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4359 - CONFIG_SYS_OR_TIMING_SDRAM:
4362 - CONFIG_SYS_MAMR_PTA:
4363 periodic timer for refresh
4365 - CONFIG_SYS_DER: Debug Event Register (37-47)
4367 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4368 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4369 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4370 CONFIG_SYS_BR1_PRELIM:
4371 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4373 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4374 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4375 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4376 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4378 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4379 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4380 Machine Mode Register and Memory Periodic Timer
4381 Prescaler definitions (SDRAM timing)
4383 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4384 enable I2C microcode relocation patch (MPC8xx);
4385 define relocation offset in DPRAM [DSP2]
4387 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4388 enable SMC microcode relocation patch (MPC8xx);
4389 define relocation offset in DPRAM [SMC1]
4391 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4392 enable SPI microcode relocation patch (MPC8xx);
4393 define relocation offset in DPRAM [SCC4]
4395 - CONFIG_SYS_USE_OSCCLK:
4396 Use OSCM clock mode on MBX8xx board. Be careful,
4397 wrong setting might damage your board. Read
4398 doc/README.MBX before setting this variable!
4400 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4401 Offset of the bootmode word in DPRAM used by post
4402 (Power On Self Tests). This definition overrides
4403 #define'd default value in commproc.h resp.
4406 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4407 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4408 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4409 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4410 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4411 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4412 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4413 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4414 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4416 - CONFIG_PCI_DISABLE_PCIE:
4417 Disable PCI-Express on systems where it is supported but not
4420 - CONFIG_PCI_ENUM_ONLY
4421 Only scan through and get the devices on the busses.
4422 Don't do any setup work, presumably because someone or
4423 something has already done it, and we don't need to do it
4424 a second time. Useful for platforms that are pre-booted
4425 by coreboot or similar.
4427 - CONFIG_PCI_INDIRECT_BRIDGE:
4428 Enable support for indirect PCI bridges.
4431 Chip has SRIO or not
4434 Board has SRIO 1 port available
4437 Board has SRIO 2 port available
4439 - CONFIG_SRIO_PCIE_BOOT_MASTER
4440 Board can support master function for Boot from SRIO and PCIE
4442 - CONFIG_SYS_SRIOn_MEM_VIRT:
4443 Virtual Address of SRIO port 'n' memory region
4445 - CONFIG_SYS_SRIOn_MEM_PHYS:
4446 Physical Address of SRIO port 'n' memory region
4448 - CONFIG_SYS_SRIOn_MEM_SIZE:
4449 Size of SRIO port 'n' memory region
4451 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4452 Defined to tell the NAND controller that the NAND chip is using
4454 Not all NAND drivers use this symbol.
4455 Example of drivers that use it:
4456 - drivers/mtd/nand/ndfc.c
4457 - drivers/mtd/nand/mxc_nand.c
4459 - CONFIG_SYS_NDFC_EBC0_CFG
4460 Sets the EBC0_CFG register for the NDFC. If not defined
4461 a default value will be used.
4464 Get DDR timing information from an I2C EEPROM. Common
4465 with pluggable memory modules such as SODIMMs
4468 I2C address of the SPD EEPROM
4470 - CONFIG_SYS_SPD_BUS_NUM
4471 If SPD EEPROM is on an I2C bus other than the first
4472 one, specify here. Note that the value must resolve
4473 to something your driver can deal with.
4475 - CONFIG_SYS_DDR_RAW_TIMING
4476 Get DDR timing information from other than SPD. Common with
4477 soldered DDR chips onboard without SPD. DDR raw timing
4478 parameters are extracted from datasheet and hard-coded into
4479 header files or board specific files.
4481 - CONFIG_FSL_DDR_INTERACTIVE
4482 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4484 - CONFIG_SYS_83XX_DDR_USES_CS0
4485 Only for 83xx systems. If specified, then DDR should
4486 be configured using CS0 and CS1 instead of CS2 and CS3.
4488 - CONFIG_ETHER_ON_FEC[12]
4489 Define to enable FEC[12] on a 8xx series processor.
4491 - CONFIG_FEC[12]_PHY
4492 Define to the hardcoded PHY address which corresponds
4493 to the given FEC; i. e.
4494 #define CONFIG_FEC1_PHY 4
4495 means that the PHY with address 4 is connected to FEC1
4497 When set to -1, means to probe for first available.
4499 - CONFIG_FEC[12]_PHY_NORXERR
4500 The PHY does not have a RXERR line (RMII only).
4501 (so program the FEC to ignore it).
4504 Enable RMII mode for all FECs.
4505 Note that this is a global option, we can't
4506 have one FEC in standard MII mode and another in RMII mode.
4508 - CONFIG_CRC32_VERIFY
4509 Add a verify option to the crc32 command.
4512 => crc32 -v <address> <count> <crc32>
4514 Where address/count indicate a memory area
4515 and crc32 is the correct crc32 which the
4519 Add the "loopw" memory command. This only takes effect if
4520 the memory commands are activated globally (CONFIG_CMD_MEM).
4523 Add the "mdc" and "mwc" memory commands. These are cyclic
4528 This command will print 4 bytes (10,11,12,13) each 500 ms.
4530 => mwc.l 100 12345678 10
4531 This command will write 12345678 to address 100 all 10 ms.
4533 This only takes effect if the memory commands are activated
4534 globally (CONFIG_CMD_MEM).
4536 - CONFIG_SKIP_LOWLEVEL_INIT
4537 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4538 low level initializations (like setting up the memory
4539 controller) are omitted and/or U-Boot does not
4540 relocate itself into RAM.
4542 Normally this variable MUST NOT be defined. The only
4543 exception is when U-Boot is loaded (to RAM) by some
4544 other boot loader or by a debugger which performs
4545 these initializations itself.
4548 Modifies the behaviour of start.S when compiling a loader
4549 that is executed before the actual U-Boot. E.g. when
4550 compiling a NAND SPL.
4553 Modifies the behaviour of start.S when compiling a loader
4554 that is executed after the SPL and before the actual U-Boot.
4555 It is loaded by the SPL.
4557 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4558 Only for 85xx systems. If this variable is specified, the section
4559 .resetvec is not kept and the section .bootpg is placed in the
4560 previous 4k of the .text section.
4562 - CONFIG_ARCH_MAP_SYSMEM
4563 Generally U-Boot (and in particular the md command) uses
4564 effective address. It is therefore not necessary to regard
4565 U-Boot address as virtual addresses that need to be translated
4566 to physical addresses. However, sandbox requires this, since
4567 it maintains its own little RAM buffer which contains all
4568 addressable memory. This option causes some memory accesses
4569 to be mapped through map_sysmem() / unmap_sysmem().
4571 - CONFIG_USE_ARCH_MEMCPY
4572 CONFIG_USE_ARCH_MEMSET
4573 If these options are used a optimized version of memcpy/memset will
4574 be used if available. These functions may be faster under some
4575 conditions but may increase the binary size.
4577 - CONFIG_X86_RESET_VECTOR
4578 If defined, the x86 reset vector code is included. This is not
4579 needed when U-Boot is running from Coreboot.
4582 Defines the MPU clock speed (in MHz).
4584 NOTE : currently only supported on AM335x platforms.
4586 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4587 Enables the RTC32K OSC on AM33xx based plattforms
4589 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4590 Option to disable subpage write in NAND driver
4591 driver that uses this:
4592 drivers/mtd/nand/davinci_nand.c
4594 Freescale QE/FMAN Firmware Support:
4595 -----------------------------------
4597 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4598 loading of "firmware", which is encoded in the QE firmware binary format.
4599 This firmware often needs to be loaded during U-Boot booting, so macros
4600 are used to identify the storage device (NOR flash, SPI, etc) and the address
4603 - CONFIG_SYS_FMAN_FW_ADDR
4604 The address in the storage device where the FMAN microcode is located. The
4605 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4608 - CONFIG_SYS_QE_FW_ADDR
4609 The address in the storage device where the QE microcode is located. The
4610 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4613 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4614 The maximum possible size of the firmware. The firmware binary format
4615 has a field that specifies the actual size of the firmware, but it
4616 might not be possible to read any part of the firmware unless some
4617 local storage is allocated to hold the entire firmware first.
4619 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4620 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4621 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4622 virtual address in NOR flash.
4624 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4625 Specifies that QE/FMAN firmware is located in NAND flash.
4626 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4628 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4629 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4630 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4632 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4633 Specifies that QE/FMAN firmware is located on the primary SPI
4634 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4636 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4637 Specifies that QE/FMAN firmware is located in the remote (master)
4638 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4639 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4640 window->master inbound window->master LAW->the ucode address in
4641 master's memory space.
4643 Building the Software:
4644 ======================
4646 Building U-Boot has been tested in several native build environments
4647 and in many different cross environments. Of course we cannot support
4648 all possibly existing versions of cross development tools in all
4649 (potentially obsolete) versions. In case of tool chain problems we
4650 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4651 which is extensively used to build and test U-Boot.
4653 If you are not using a native environment, it is assumed that you
4654 have GNU cross compiling tools available in your path. In this case,
4655 you must set the environment variable CROSS_COMPILE in your shell.
4656 Note that no changes to the Makefile or any other source files are
4657 necessary. For example using the ELDK on a 4xx CPU, please enter:
4659 $ CROSS_COMPILE=ppc_4xx-
4660 $ export CROSS_COMPILE
4662 Note: If you wish to generate Windows versions of the utilities in
4663 the tools directory you can use the MinGW toolchain
4664 (http://www.mingw.org). Set your HOST tools to the MinGW
4665 toolchain and execute 'make tools'. For example:
4667 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4669 Binaries such as tools/mkimage.exe will be created which can
4670 be executed on computers running Windows.
4672 U-Boot is intended to be simple to build. After installing the
4673 sources you must configure U-Boot for one specific board type. This
4678 where "NAME_config" is the name of one of the existing configu-
4679 rations; see boards.cfg for supported names.
4681 Note: for some board special configuration names may exist; check if
4682 additional information is available from the board vendor; for
4683 instance, the TQM823L systems are available without (standard)
4684 or with LCD support. You can select such additional "features"
4685 when choosing the configuration, i. e.
4688 - will configure for a plain TQM823L, i. e. no LCD support
4690 make TQM823L_LCD_config
4691 - will configure for a TQM823L with U-Boot console on LCD
4696 Finally, type "make all", and you should get some working U-Boot
4697 images ready for download to / installation on your system:
4699 - "u-boot.bin" is a raw binary image
4700 - "u-boot" is an image in ELF binary format
4701 - "u-boot.srec" is in Motorola S-Record format
4703 By default the build is performed locally and the objects are saved
4704 in the source directory. One of the two methods can be used to change
4705 this behavior and build U-Boot to some external directory:
4707 1. Add O= to the make command line invocations:
4709 make O=/tmp/build distclean
4710 make O=/tmp/build NAME_config
4711 make O=/tmp/build all
4713 2. Set environment variable BUILD_DIR to point to the desired location:
4715 export BUILD_DIR=/tmp/build
4720 Note that the command line "O=" setting overrides the BUILD_DIR environment
4724 Please be aware that the Makefiles assume you are using GNU make, so
4725 for instance on NetBSD you might need to use "gmake" instead of
4729 If the system board that you have is not listed, then you will need
4730 to port U-Boot to your hardware platform. To do this, follow these
4733 1. Add a new configuration option for your board to the toplevel
4734 "boards.cfg" file, using the existing entries as examples.
4735 Follow the instructions there to keep the boards in order.
4736 2. Create a new directory to hold your board specific code. Add any
4737 files you need. In your board directory, you will need at least
4738 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4739 3. Create a new configuration file "include/configs/<board>.h" for
4741 3. If you're porting U-Boot to a new CPU, then also create a new
4742 directory to hold your CPU specific code. Add any files you need.
4743 4. Run "make <board>_config" with your new name.
4744 5. Type "make", and you should get a working "u-boot.srec" file
4745 to be installed on your target system.
4746 6. Debug and solve any problems that might arise.
4747 [Of course, this last step is much harder than it sounds.]
4750 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4751 ==============================================================
4753 If you have modified U-Boot sources (for instance added a new board
4754 or support for new devices, a new CPU, etc.) you are expected to
4755 provide feedback to the other developers. The feedback normally takes
4756 the form of a "patch", i. e. a context diff against a certain (latest
4757 official or latest in the git repository) version of U-Boot sources.
4759 But before you submit such a patch, please verify that your modifi-
4760 cation did not break existing code. At least make sure that *ALL* of
4761 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4762 just run the "MAKEALL" script, which will configure and build U-Boot
4763 for ALL supported system. Be warned, this will take a while. You can
4764 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4765 environment variable to the script, i. e. to use the ELDK cross tools
4768 CROSS_COMPILE=ppc_8xx- MAKEALL
4770 or to build on a native PowerPC system you can type
4772 CROSS_COMPILE=' ' MAKEALL
4774 When using the MAKEALL script, the default behaviour is to build
4775 U-Boot in the source directory. This location can be changed by
4776 setting the BUILD_DIR environment variable. Also, for each target
4777 built, the MAKEALL script saves two log files (<target>.ERR and
4778 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4779 location can be changed by setting the MAKEALL_LOGDIR environment
4780 variable. For example:
4782 export BUILD_DIR=/tmp/build
4783 export MAKEALL_LOGDIR=/tmp/log
4784 CROSS_COMPILE=ppc_8xx- MAKEALL
4786 With the above settings build objects are saved in the /tmp/build,
4787 log files are saved in the /tmp/log and the source tree remains clean
4788 during the whole build process.
4791 See also "U-Boot Porting Guide" below.
4794 Monitor Commands - Overview:
4795 ============================
4797 go - start application at address 'addr'
4798 run - run commands in an environment variable
4799 bootm - boot application image from memory
4800 bootp - boot image via network using BootP/TFTP protocol
4801 bootz - boot zImage from memory
4802 tftpboot- boot image via network using TFTP protocol
4803 and env variables "ipaddr" and "serverip"
4804 (and eventually "gatewayip")
4805 tftpput - upload a file via network using TFTP protocol
4806 rarpboot- boot image via network using RARP/TFTP protocol
4807 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4808 loads - load S-Record file over serial line
4809 loadb - load binary file over serial line (kermit mode)
4811 mm - memory modify (auto-incrementing)
4812 nm - memory modify (constant address)
4813 mw - memory write (fill)
4815 cmp - memory compare
4816 crc32 - checksum calculation
4817 i2c - I2C sub-system
4818 sspi - SPI utility commands
4819 base - print or set address offset
4820 printenv- print environment variables
4821 setenv - set environment variables
4822 saveenv - save environment variables to persistent storage
4823 protect - enable or disable FLASH write protection
4824 erase - erase FLASH memory
4825 flinfo - print FLASH memory information
4826 nand - NAND memory operations (see doc/README.nand)
4827 bdinfo - print Board Info structure
4828 iminfo - print header information for application image
4829 coninfo - print console devices and informations
4830 ide - IDE sub-system
4831 loop - infinite loop on address range
4832 loopw - infinite write loop on address range
4833 mtest - simple RAM test
4834 icache - enable or disable instruction cache
4835 dcache - enable or disable data cache
4836 reset - Perform RESET of the CPU
4837 echo - echo args to console
4838 version - print monitor version
4839 help - print online help
4840 ? - alias for 'help'
4843 Monitor Commands - Detailed Description:
4844 ========================================
4848 For now: just type "help <command>".
4851 Environment Variables:
4852 ======================
4854 U-Boot supports user configuration using Environment Variables which
4855 can be made persistent by saving to Flash memory.
4857 Environment Variables are set using "setenv", printed using
4858 "printenv", and saved to Flash using "saveenv". Using "setenv"
4859 without a value can be used to delete a variable from the
4860 environment. As long as you don't save the environment you are
4861 working with an in-memory copy. In case the Flash area containing the
4862 environment is erased by accident, a default environment is provided.
4864 Some configuration options can be set using Environment Variables.
4866 List of environment variables (most likely not complete):
4868 baudrate - see CONFIG_BAUDRATE
4870 bootdelay - see CONFIG_BOOTDELAY
4872 bootcmd - see CONFIG_BOOTCOMMAND
4874 bootargs - Boot arguments when booting an RTOS image
4876 bootfile - Name of the image to load with TFTP
4878 bootm_low - Memory range available for image processing in the bootm
4879 command can be restricted. This variable is given as
4880 a hexadecimal number and defines lowest address allowed
4881 for use by the bootm command. See also "bootm_size"
4882 environment variable. Address defined by "bootm_low" is
4883 also the base of the initial memory mapping for the Linux
4884 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4887 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4888 This variable is given as a hexadecimal number and it
4889 defines the size of the memory region starting at base
4890 address bootm_low that is accessible by the Linux kernel
4891 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4892 as the default value if it is defined, and bootm_size is
4895 bootm_size - Memory range available for image processing in the bootm
4896 command can be restricted. This variable is given as
4897 a hexadecimal number and defines the size of the region
4898 allowed for use by the bootm command. See also "bootm_low"
4899 environment variable.
4901 updatefile - Location of the software update file on a TFTP server, used
4902 by the automatic software update feature. Please refer to
4903 documentation in doc/README.update for more details.
4905 autoload - if set to "no" (any string beginning with 'n'),
4906 "bootp" will just load perform a lookup of the
4907 configuration from the BOOTP server, but not try to
4908 load any image using TFTP
4910 autostart - if set to "yes", an image loaded using the "bootp",
4911 "rarpboot", "tftpboot" or "diskboot" commands will
4912 be automatically started (by internally calling
4915 If set to "no", a standalone image passed to the
4916 "bootm" command will be copied to the load address
4917 (and eventually uncompressed), but NOT be started.
4918 This can be used to load and uncompress arbitrary
4921 fdt_high - if set this restricts the maximum address that the
4922 flattened device tree will be copied into upon boot.
4923 For example, if you have a system with 1 GB memory
4924 at physical address 0x10000000, while Linux kernel
4925 only recognizes the first 704 MB as low memory, you
4926 may need to set fdt_high as 0x3C000000 to have the
4927 device tree blob be copied to the maximum address
4928 of the 704 MB low memory, so that Linux kernel can
4929 access it during the boot procedure.
4931 If this is set to the special value 0xFFFFFFFF then
4932 the fdt will not be copied at all on boot. For this
4933 to work it must reside in writable memory, have
4934 sufficient padding on the end of it for u-boot to
4935 add the information it needs into it, and the memory
4936 must be accessible by the kernel.
4938 fdtcontroladdr- if set this is the address of the control flattened
4939 device tree used by U-Boot when CONFIG_OF_CONTROL is
4942 i2cfast - (PPC405GP|PPC405EP only)
4943 if set to 'y' configures Linux I2C driver for fast
4944 mode (400kHZ). This environment variable is used in
4945 initialization code. So, for changes to be effective
4946 it must be saved and board must be reset.
4948 initrd_high - restrict positioning of initrd images:
4949 If this variable is not set, initrd images will be
4950 copied to the highest possible address in RAM; this
4951 is usually what you want since it allows for
4952 maximum initrd size. If for some reason you want to
4953 make sure that the initrd image is loaded below the
4954 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4955 variable to a value of "no" or "off" or "0".
4956 Alternatively, you can set it to a maximum upper
4957 address to use (U-Boot will still check that it
4958 does not overwrite the U-Boot stack and data).
4960 For instance, when you have a system with 16 MB
4961 RAM, and want to reserve 4 MB from use by Linux,
4962 you can do this by adding "mem=12M" to the value of
4963 the "bootargs" variable. However, now you must make
4964 sure that the initrd image is placed in the first
4965 12 MB as well - this can be done with
4967 setenv initrd_high 00c00000
4969 If you set initrd_high to 0xFFFFFFFF, this is an
4970 indication to U-Boot that all addresses are legal
4971 for the Linux kernel, including addresses in flash
4972 memory. In this case U-Boot will NOT COPY the
4973 ramdisk at all. This may be useful to reduce the
4974 boot time on your system, but requires that this
4975 feature is supported by your Linux kernel.
4977 ipaddr - IP address; needed for tftpboot command
4979 loadaddr - Default load address for commands like "bootp",
4980 "rarpboot", "tftpboot", "loadb" or "diskboot"
4982 loads_echo - see CONFIG_LOADS_ECHO
4984 serverip - TFTP server IP address; needed for tftpboot command
4986 bootretry - see CONFIG_BOOT_RETRY_TIME
4988 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4990 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4992 ethprime - controls which interface is used first.
4994 ethact - controls which interface is currently active.
4995 For example you can do the following
4997 => setenv ethact FEC
4998 => ping 192.168.0.1 # traffic sent on FEC
4999 => setenv ethact SCC
5000 => ping 10.0.0.1 # traffic sent on SCC
5002 ethrotate - When set to "no" U-Boot does not go through all
5003 available network interfaces.
5004 It just stays at the currently selected interface.
5006 netretry - When set to "no" each network operation will
5007 either succeed or fail without retrying.
5008 When set to "once" the network operation will
5009 fail when all the available network interfaces
5010 are tried once without success.
5011 Useful on scripts which control the retry operation
5014 npe_ucode - set load address for the NPE microcode
5016 silent_linux - If set then linux will be told to boot silently, by
5017 changing the console to be empty. If "yes" it will be
5018 made silent. If "no" it will not be made silent. If
5019 unset, then it will be made silent if the U-Boot console
5022 tftpsrcport - If this is set, the value is used for TFTP's
5025 tftpdstport - If this is set, the value is used for TFTP's UDP
5026 destination port instead of the Well Know Port 69.
5028 tftpblocksize - Block size to use for TFTP transfers; if not set,
5029 we use the TFTP server's default block size
5031 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5032 seconds, minimum value is 1000 = 1 second). Defines
5033 when a packet is considered to be lost so it has to
5034 be retransmitted. The default is 5000 = 5 seconds.
5035 Lowering this value may make downloads succeed
5036 faster in networks with high packet loss rates or
5037 with unreliable TFTP servers.
5039 vlan - When set to a value < 4095 the traffic over
5040 Ethernet is encapsulated/received over 802.1q
5043 The following image location variables contain the location of images
5044 used in booting. The "Image" column gives the role of the image and is
5045 not an environment variable name. The other columns are environment
5046 variable names. "File Name" gives the name of the file on a TFTP
5047 server, "RAM Address" gives the location in RAM the image will be
5048 loaded to, and "Flash Location" gives the image's address in NOR
5049 flash or offset in NAND flash.
5051 *Note* - these variables don't have to be defined for all boards, some
5052 boards currenlty use other variables for these purposes, and some
5053 boards use these variables for other purposes.
5055 Image File Name RAM Address Flash Location
5056 ----- --------- ----------- --------------
5057 u-boot u-boot u-boot_addr_r u-boot_addr
5058 Linux kernel bootfile kernel_addr_r kernel_addr
5059 device tree blob fdtfile fdt_addr_r fdt_addr
5060 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5062 The following environment variables may be used and automatically
5063 updated by the network boot commands ("bootp" and "rarpboot"),
5064 depending the information provided by your boot server:
5066 bootfile - see above
5067 dnsip - IP address of your Domain Name Server
5068 dnsip2 - IP address of your secondary Domain Name Server
5069 gatewayip - IP address of the Gateway (Router) to use
5070 hostname - Target hostname
5072 netmask - Subnet Mask
5073 rootpath - Pathname of the root filesystem on the NFS server
5074 serverip - see above
5077 There are two special Environment Variables:
5079 serial# - contains hardware identification information such
5080 as type string and/or serial number
5081 ethaddr - Ethernet address
5083 These variables can be set only once (usually during manufacturing of
5084 the board). U-Boot refuses to delete or overwrite these variables
5085 once they have been set once.
5088 Further special Environment Variables:
5090 ver - Contains the U-Boot version string as printed
5091 with the "version" command. This variable is
5092 readonly (see CONFIG_VERSION_VARIABLE).
5095 Please note that changes to some configuration parameters may take
5096 only effect after the next boot (yes, that's just like Windoze :-).
5099 Callback functions for environment variables:
5100 ---------------------------------------------
5102 For some environment variables, the behavior of u-boot needs to change
5103 when their values are changed. This functionailty allows functions to
5104 be associated with arbitrary variables. On creation, overwrite, or
5105 deletion, the callback will provide the opportunity for some side
5106 effect to happen or for the change to be rejected.
5108 The callbacks are named and associated with a function using the
5109 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5111 These callbacks are associated with variables in one of two ways. The
5112 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5113 in the board configuration to a string that defines a list of
5114 associations. The list must be in the following format:
5116 entry = variable_name[:callback_name]
5119 If the callback name is not specified, then the callback is deleted.
5120 Spaces are also allowed anywhere in the list.
5122 Callbacks can also be associated by defining the ".callbacks" variable
5123 with the same list format above. Any association in ".callbacks" will
5124 override any association in the static list. You can define
5125 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5126 ".callbacks" envirnoment variable in the default or embedded environment.
5129 Command Line Parsing:
5130 =====================
5132 There are two different command line parsers available with U-Boot:
5133 the old "simple" one, and the much more powerful "hush" shell:
5135 Old, simple command line parser:
5136 --------------------------------
5138 - supports environment variables (through setenv / saveenv commands)
5139 - several commands on one line, separated by ';'
5140 - variable substitution using "... ${name} ..." syntax
5141 - special characters ('$', ';') can be escaped by prefixing with '\',
5143 setenv bootcmd bootm \${address}
5144 - You can also escape text by enclosing in single apostrophes, for example:
5145 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5150 - similar to Bourne shell, with control structures like
5151 if...then...else...fi, for...do...done; while...do...done,
5152 until...do...done, ...
5153 - supports environment ("global") variables (through setenv / saveenv
5154 commands) and local shell variables (through standard shell syntax
5155 "name=value"); only environment variables can be used with "run"
5161 (1) If a command line (or an environment variable executed by a "run"
5162 command) contains several commands separated by semicolon, and
5163 one of these commands fails, then the remaining commands will be
5166 (2) If you execute several variables with one call to run (i. e.
5167 calling run with a list of variables as arguments), any failing
5168 command will cause "run" to terminate, i. e. the remaining
5169 variables are not executed.
5171 Note for Redundant Ethernet Interfaces:
5172 =======================================
5174 Some boards come with redundant Ethernet interfaces; U-Boot supports
5175 such configurations and is capable of automatic selection of a
5176 "working" interface when needed. MAC assignment works as follows:
5178 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5179 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5180 "eth1addr" (=>eth1), "eth2addr", ...
5182 If the network interface stores some valid MAC address (for instance
5183 in SROM), this is used as default address if there is NO correspon-
5184 ding setting in the environment; if the corresponding environment
5185 variable is set, this overrides the settings in the card; that means:
5187 o If the SROM has a valid MAC address, and there is no address in the
5188 environment, the SROM's address is used.
5190 o If there is no valid address in the SROM, and a definition in the
5191 environment exists, then the value from the environment variable is
5194 o If both the SROM and the environment contain a MAC address, and
5195 both addresses are the same, this MAC address is used.
5197 o If both the SROM and the environment contain a MAC address, and the
5198 addresses differ, the value from the environment is used and a
5201 o If neither SROM nor the environment contain a MAC address, an error
5204 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5205 will be programmed into hardware as part of the initialization process. This
5206 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5207 The naming convention is as follows:
5208 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5213 U-Boot is capable of booting (and performing other auxiliary operations on)
5214 images in two formats:
5216 New uImage format (FIT)
5217 -----------------------
5219 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5220 to Flattened Device Tree). It allows the use of images with multiple
5221 components (several kernels, ramdisks, etc.), with contents protected by
5222 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5228 Old image format is based on binary files which can be basically anything,
5229 preceded by a special header; see the definitions in include/image.h for
5230 details; basically, the header defines the following image properties:
5232 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5233 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5234 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5235 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5237 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5238 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5239 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5240 * Compression Type (uncompressed, gzip, bzip2)
5246 The header is marked by a special Magic Number, and both the header
5247 and the data portions of the image are secured against corruption by
5254 Although U-Boot should support any OS or standalone application
5255 easily, the main focus has always been on Linux during the design of
5258 U-Boot includes many features that so far have been part of some
5259 special "boot loader" code within the Linux kernel. Also, any
5260 "initrd" images to be used are no longer part of one big Linux image;
5261 instead, kernel and "initrd" are separate images. This implementation
5262 serves several purposes:
5264 - the same features can be used for other OS or standalone
5265 applications (for instance: using compressed images to reduce the
5266 Flash memory footprint)
5268 - it becomes much easier to port new Linux kernel versions because
5269 lots of low-level, hardware dependent stuff are done by U-Boot
5271 - the same Linux kernel image can now be used with different "initrd"
5272 images; of course this also means that different kernel images can
5273 be run with the same "initrd". This makes testing easier (you don't
5274 have to build a new "zImage.initrd" Linux image when you just
5275 change a file in your "initrd"). Also, a field-upgrade of the
5276 software is easier now.
5282 Porting Linux to U-Boot based systems:
5283 ---------------------------------------
5285 U-Boot cannot save you from doing all the necessary modifications to
5286 configure the Linux device drivers for use with your target hardware
5287 (no, we don't intend to provide a full virtual machine interface to
5290 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5292 Just make sure your machine specific header file (for instance
5293 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5294 Information structure as we define in include/asm-<arch>/u-boot.h,
5295 and make sure that your definition of IMAP_ADDR uses the same value
5296 as your U-Boot configuration in CONFIG_SYS_IMMR.
5299 Configuring the Linux kernel:
5300 -----------------------------
5302 No specific requirements for U-Boot. Make sure you have some root
5303 device (initial ramdisk, NFS) for your target system.
5306 Building a Linux Image:
5307 -----------------------
5309 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5310 not used. If you use recent kernel source, a new build target
5311 "uImage" will exist which automatically builds an image usable by
5312 U-Boot. Most older kernels also have support for a "pImage" target,
5313 which was introduced for our predecessor project PPCBoot and uses a
5314 100% compatible format.
5323 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5324 encapsulate a compressed Linux kernel image with header information,
5325 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5327 * build a standard "vmlinux" kernel image (in ELF binary format):
5329 * convert the kernel into a raw binary image:
5331 ${CROSS_COMPILE}-objcopy -O binary \
5332 -R .note -R .comment \
5333 -S vmlinux linux.bin
5335 * compress the binary image:
5339 * package compressed binary image for U-Boot:
5341 mkimage -A ppc -O linux -T kernel -C gzip \
5342 -a 0 -e 0 -n "Linux Kernel Image" \
5343 -d linux.bin.gz uImage
5346 The "mkimage" tool can also be used to create ramdisk images for use
5347 with U-Boot, either separated from the Linux kernel image, or
5348 combined into one file. "mkimage" encapsulates the images with a 64
5349 byte header containing information about target architecture,
5350 operating system, image type, compression method, entry points, time
5351 stamp, CRC32 checksums, etc.
5353 "mkimage" can be called in two ways: to verify existing images and
5354 print the header information, or to build new images.
5356 In the first form (with "-l" option) mkimage lists the information
5357 contained in the header of an existing U-Boot image; this includes
5358 checksum verification:
5360 tools/mkimage -l image
5361 -l ==> list image header information
5363 The second form (with "-d" option) is used to build a U-Boot image
5364 from a "data file" which is used as image payload:
5366 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5367 -n name -d data_file image
5368 -A ==> set architecture to 'arch'
5369 -O ==> set operating system to 'os'
5370 -T ==> set image type to 'type'
5371 -C ==> set compression type 'comp'
5372 -a ==> set load address to 'addr' (hex)
5373 -e ==> set entry point to 'ep' (hex)
5374 -n ==> set image name to 'name'
5375 -d ==> use image data from 'datafile'
5377 Right now, all Linux kernels for PowerPC systems use the same load
5378 address (0x00000000), but the entry point address depends on the
5381 - 2.2.x kernels have the entry point at 0x0000000C,
5382 - 2.3.x and later kernels have the entry point at 0x00000000.
5384 So a typical call to build a U-Boot image would read:
5386 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5387 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5388 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5389 > examples/uImage.TQM850L
5390 Image Name: 2.4.4 kernel for TQM850L
5391 Created: Wed Jul 19 02:34:59 2000
5392 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5393 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5394 Load Address: 0x00000000
5395 Entry Point: 0x00000000
5397 To verify the contents of the image (or check for corruption):
5399 -> tools/mkimage -l examples/uImage.TQM850L
5400 Image Name: 2.4.4 kernel for TQM850L
5401 Created: Wed Jul 19 02:34:59 2000
5402 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5403 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5404 Load Address: 0x00000000
5405 Entry Point: 0x00000000
5407 NOTE: for embedded systems where boot time is critical you can trade
5408 speed for memory and install an UNCOMPRESSED image instead: this
5409 needs more space in Flash, but boots much faster since it does not
5410 need to be uncompressed:
5412 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5413 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5414 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5415 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5416 > examples/uImage.TQM850L-uncompressed
5417 Image Name: 2.4.4 kernel for TQM850L
5418 Created: Wed Jul 19 02:34:59 2000
5419 Image Type: PowerPC Linux Kernel Image (uncompressed)
5420 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5421 Load Address: 0x00000000
5422 Entry Point: 0x00000000
5425 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5426 when your kernel is intended to use an initial ramdisk:
5428 -> tools/mkimage -n 'Simple Ramdisk Image' \
5429 > -A ppc -O linux -T ramdisk -C gzip \
5430 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5431 Image Name: Simple Ramdisk Image
5432 Created: Wed Jan 12 14:01:50 2000
5433 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5434 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5435 Load Address: 0x00000000
5436 Entry Point: 0x00000000
5438 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5439 option performs the converse operation of the mkimage's second form (the "-d"
5440 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5443 tools/dumpimage -i image -p position data_file
5444 -i ==> extract from the 'image' a specific 'data_file', \
5445 indexed by 'position'
5448 Installing a Linux Image:
5449 -------------------------
5451 To downloading a U-Boot image over the serial (console) interface,
5452 you must convert the image to S-Record format:
5454 objcopy -I binary -O srec examples/image examples/image.srec
5456 The 'objcopy' does not understand the information in the U-Boot
5457 image header, so the resulting S-Record file will be relative to
5458 address 0x00000000. To load it to a given address, you need to
5459 specify the target address as 'offset' parameter with the 'loads'
5462 Example: install the image to address 0x40100000 (which on the
5463 TQM8xxL is in the first Flash bank):
5465 => erase 40100000 401FFFFF
5471 ## Ready for S-Record download ...
5472 ~>examples/image.srec
5473 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5475 15989 15990 15991 15992
5476 [file transfer complete]
5478 ## Start Addr = 0x00000000
5481 You can check the success of the download using the 'iminfo' command;
5482 this includes a checksum verification so you can be sure no data
5483 corruption happened:
5487 ## Checking Image at 40100000 ...
5488 Image Name: 2.2.13 for initrd on TQM850L
5489 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5490 Data Size: 335725 Bytes = 327 kB = 0 MB
5491 Load Address: 00000000
5492 Entry Point: 0000000c
5493 Verifying Checksum ... OK
5499 The "bootm" command is used to boot an application that is stored in
5500 memory (RAM or Flash). In case of a Linux kernel image, the contents
5501 of the "bootargs" environment variable is passed to the kernel as
5502 parameters. You can check and modify this variable using the
5503 "printenv" and "setenv" commands:
5506 => printenv bootargs
5507 bootargs=root=/dev/ram
5509 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5511 => printenv bootargs
5512 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5515 ## Booting Linux kernel at 40020000 ...
5516 Image Name: 2.2.13 for NFS on TQM850L
5517 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5518 Data Size: 381681 Bytes = 372 kB = 0 MB
5519 Load Address: 00000000
5520 Entry Point: 0000000c
5521 Verifying Checksum ... OK
5522 Uncompressing Kernel Image ... OK
5523 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
5524 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5525 time_init: decrementer frequency = 187500000/60
5526 Calibrating delay loop... 49.77 BogoMIPS
5527 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5530 If you want to boot a Linux kernel with initial RAM disk, you pass
5531 the memory addresses of both the kernel and the initrd image (PPBCOOT
5532 format!) to the "bootm" command:
5534 => imi 40100000 40200000
5536 ## Checking Image at 40100000 ...
5537 Image Name: 2.2.13 for initrd on TQM850L
5538 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5539 Data Size: 335725 Bytes = 327 kB = 0 MB
5540 Load Address: 00000000
5541 Entry Point: 0000000c
5542 Verifying Checksum ... OK
5544 ## Checking Image at 40200000 ...
5545 Image Name: Simple Ramdisk Image
5546 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5547 Data Size: 566530 Bytes = 553 kB = 0 MB
5548 Load Address: 00000000
5549 Entry Point: 00000000
5550 Verifying Checksum ... OK
5552 => bootm 40100000 40200000
5553 ## Booting Linux kernel at 40100000 ...
5554 Image Name: 2.2.13 for initrd on TQM850L
5555 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5556 Data Size: 335725 Bytes = 327 kB = 0 MB
5557 Load Address: 00000000
5558 Entry Point: 0000000c
5559 Verifying Checksum ... OK
5560 Uncompressing Kernel Image ... OK
5561 ## Loading RAMDisk Image at 40200000 ...
5562 Image Name: Simple Ramdisk Image
5563 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5564 Data Size: 566530 Bytes = 553 kB = 0 MB
5565 Load Address: 00000000
5566 Entry Point: 00000000
5567 Verifying Checksum ... OK
5568 Loading Ramdisk ... OK
5569 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
5570 Boot arguments: root=/dev/ram
5571 time_init: decrementer frequency = 187500000/60
5572 Calibrating delay loop... 49.77 BogoMIPS
5574 RAMDISK: Compressed image found at block 0
5575 VFS: Mounted root (ext2 filesystem).
5579 Boot Linux and pass a flat device tree:
5582 First, U-Boot must be compiled with the appropriate defines. See the section
5583 titled "Linux Kernel Interface" above for a more in depth explanation. The
5584 following is an example of how to start a kernel and pass an updated
5590 oft=oftrees/mpc8540ads.dtb
5591 => tftp $oftaddr $oft
5592 Speed: 1000, full duplex
5594 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5595 Filename 'oftrees/mpc8540ads.dtb'.
5596 Load address: 0x300000
5599 Bytes transferred = 4106 (100a hex)
5600 => tftp $loadaddr $bootfile
5601 Speed: 1000, full duplex
5603 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5605 Load address: 0x200000
5606 Loading:############
5608 Bytes transferred = 1029407 (fb51f hex)
5613 => bootm $loadaddr - $oftaddr
5614 ## Booting image at 00200000 ...
5615 Image Name: Linux-2.6.17-dirty
5616 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5617 Data Size: 1029343 Bytes = 1005.2 kB
5618 Load Address: 00000000
5619 Entry Point: 00000000
5620 Verifying Checksum ... OK
5621 Uncompressing Kernel Image ... OK
5622 Booting using flat device tree at 0x300000
5623 Using MPC85xx ADS machine description
5624 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5628 More About U-Boot Image Types:
5629 ------------------------------
5631 U-Boot supports the following image types:
5633 "Standalone Programs" are directly runnable in the environment
5634 provided by U-Boot; it is expected that (if they behave
5635 well) you can continue to work in U-Boot after return from
5636 the Standalone Program.
5637 "OS Kernel Images" are usually images of some Embedded OS which
5638 will take over control completely. Usually these programs
5639 will install their own set of exception handlers, device
5640 drivers, set up the MMU, etc. - this means, that you cannot
5641 expect to re-enter U-Boot except by resetting the CPU.
5642 "RAMDisk Images" are more or less just data blocks, and their
5643 parameters (address, size) are passed to an OS kernel that is
5645 "Multi-File Images" contain several images, typically an OS
5646 (Linux) kernel image and one or more data images like
5647 RAMDisks. This construct is useful for instance when you want
5648 to boot over the network using BOOTP etc., where the boot
5649 server provides just a single image file, but you want to get
5650 for instance an OS kernel and a RAMDisk image.
5652 "Multi-File Images" start with a list of image sizes, each
5653 image size (in bytes) specified by an "uint32_t" in network
5654 byte order. This list is terminated by an "(uint32_t)0".
5655 Immediately after the terminating 0 follow the images, one by
5656 one, all aligned on "uint32_t" boundaries (size rounded up to
5657 a multiple of 4 bytes).
5659 "Firmware Images" are binary images containing firmware (like
5660 U-Boot or FPGA images) which usually will be programmed to
5663 "Script files" are command sequences that will be executed by
5664 U-Boot's command interpreter; this feature is especially
5665 useful when you configure U-Boot to use a real shell (hush)
5666 as command interpreter.
5668 Booting the Linux zImage:
5669 -------------------------
5671 On some platforms, it's possible to boot Linux zImage. This is done
5672 using the "bootz" command. The syntax of "bootz" command is the same
5673 as the syntax of "bootm" command.
5675 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5676 kernel with raw initrd images. The syntax is slightly different, the
5677 address of the initrd must be augmented by it's size, in the following
5678 format: "<initrd addres>:<initrd size>".
5684 One of the features of U-Boot is that you can dynamically load and
5685 run "standalone" applications, which can use some resources of
5686 U-Boot like console I/O functions or interrupt services.
5688 Two simple examples are included with the sources:
5693 'examples/hello_world.c' contains a small "Hello World" Demo
5694 application; it is automatically compiled when you build U-Boot.
5695 It's configured to run at address 0x00040004, so you can play with it
5699 ## Ready for S-Record download ...
5700 ~>examples/hello_world.srec
5701 1 2 3 4 5 6 7 8 9 10 11 ...
5702 [file transfer complete]
5704 ## Start Addr = 0x00040004
5706 => go 40004 Hello World! This is a test.
5707 ## Starting application at 0x00040004 ...
5718 Hit any key to exit ...
5720 ## Application terminated, rc = 0x0
5722 Another example, which demonstrates how to register a CPM interrupt
5723 handler with the U-Boot code, can be found in 'examples/timer.c'.
5724 Here, a CPM timer is set up to generate an interrupt every second.
5725 The interrupt service routine is trivial, just printing a '.'
5726 character, but this is just a demo program. The application can be
5727 controlled by the following keys:
5729 ? - print current values og the CPM Timer registers
5730 b - enable interrupts and start timer
5731 e - stop timer and disable interrupts
5732 q - quit application
5735 ## Ready for S-Record download ...
5736 ~>examples/timer.srec
5737 1 2 3 4 5 6 7 8 9 10 11 ...
5738 [file transfer complete]
5740 ## Start Addr = 0x00040004
5743 ## Starting application at 0x00040004 ...
5746 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5749 [q, b, e, ?] Set interval 1000000 us
5752 [q, b, e, ?] ........
5753 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5756 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5759 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5762 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5764 [q, b, e, ?] ...Stopping timer
5766 [q, b, e, ?] ## Application terminated, rc = 0x0
5772 Over time, many people have reported problems when trying to use the
5773 "minicom" terminal emulation program for serial download. I (wd)
5774 consider minicom to be broken, and recommend not to use it. Under
5775 Unix, I recommend to use C-Kermit for general purpose use (and
5776 especially for kermit binary protocol download ("loadb" command), and
5777 use "cu" for S-Record download ("loads" command). See
5778 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5779 for help with kermit.
5782 Nevertheless, if you absolutely want to use it try adding this
5783 configuration to your "File transfer protocols" section:
5785 Name Program Name U/D FullScr IO-Red. Multi
5786 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5787 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5793 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5794 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5796 Building requires a cross environment; it is known to work on
5797 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5798 need gmake since the Makefiles are not compatible with BSD make).
5799 Note that the cross-powerpc package does not install include files;
5800 attempting to build U-Boot will fail because <machine/ansi.h> is
5801 missing. This file has to be installed and patched manually:
5803 # cd /usr/pkg/cross/powerpc-netbsd/include
5805 # ln -s powerpc machine
5806 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5807 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5809 Native builds *don't* work due to incompatibilities between native
5810 and U-Boot include files.
5812 Booting assumes that (the first part of) the image booted is a
5813 stage-2 loader which in turn loads and then invokes the kernel
5814 proper. Loader sources will eventually appear in the NetBSD source
5815 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5816 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5819 Implementation Internals:
5820 =========================
5822 The following is not intended to be a complete description of every
5823 implementation detail. However, it should help to understand the
5824 inner workings of U-Boot and make it easier to port it to custom
5828 Initial Stack, Global Data:
5829 ---------------------------
5831 The implementation of U-Boot is complicated by the fact that U-Boot
5832 starts running out of ROM (flash memory), usually without access to
5833 system RAM (because the memory controller is not initialized yet).
5834 This means that we don't have writable Data or BSS segments, and BSS
5835 is not initialized as zero. To be able to get a C environment working
5836 at all, we have to allocate at least a minimal stack. Implementation
5837 options for this are defined and restricted by the CPU used: Some CPU
5838 models provide on-chip memory (like the IMMR area on MPC8xx and
5839 MPC826x processors), on others (parts of) the data cache can be
5840 locked as (mis-) used as memory, etc.
5842 Chris Hallinan posted a good summary of these issues to the
5843 U-Boot mailing list:
5845 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5846 From: "Chris Hallinan" <clh@net1plus.com>
5847 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5850 Correct me if I'm wrong, folks, but the way I understand it
5851 is this: Using DCACHE as initial RAM for Stack, etc, does not
5852 require any physical RAM backing up the cache. The cleverness
5853 is that the cache is being used as a temporary supply of
5854 necessary storage before the SDRAM controller is setup. It's
5855 beyond the scope of this list to explain the details, but you
5856 can see how this works by studying the cache architecture and
5857 operation in the architecture and processor-specific manuals.
5859 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5860 is another option for the system designer to use as an
5861 initial stack/RAM area prior to SDRAM being available. Either
5862 option should work for you. Using CS 4 should be fine if your
5863 board designers haven't used it for something that would
5864 cause you grief during the initial boot! It is frequently not
5867 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5868 with your processor/board/system design. The default value
5869 you will find in any recent u-boot distribution in
5870 walnut.h should work for you. I'd set it to a value larger
5871 than your SDRAM module. If you have a 64MB SDRAM module, set
5872 it above 400_0000. Just make sure your board has no resources
5873 that are supposed to respond to that address! That code in
5874 start.S has been around a while and should work as is when
5875 you get the config right.
5880 It is essential to remember this, since it has some impact on the C
5881 code for the initialization procedures:
5883 * Initialized global data (data segment) is read-only. Do not attempt
5886 * Do not use any uninitialized global data (or implicitely initialized
5887 as zero data - BSS segment) at all - this is undefined, initiali-
5888 zation is performed later (when relocating to RAM).
5890 * Stack space is very limited. Avoid big data buffers or things like
5893 Having only the stack as writable memory limits means we cannot use
5894 normal global data to share information beween the code. But it
5895 turned out that the implementation of U-Boot can be greatly
5896 simplified by making a global data structure (gd_t) available to all
5897 functions. We could pass a pointer to this data as argument to _all_
5898 functions, but this would bloat the code. Instead we use a feature of
5899 the GCC compiler (Global Register Variables) to share the data: we
5900 place a pointer (gd) to the global data into a register which we
5901 reserve for this purpose.
5903 When choosing a register for such a purpose we are restricted by the
5904 relevant (E)ABI specifications for the current architecture, and by
5905 GCC's implementation.
5907 For PowerPC, the following registers have specific use:
5909 R2: reserved for system use
5910 R3-R4: parameter passing and return values
5911 R5-R10: parameter passing
5912 R13: small data area pointer
5916 (U-Boot also uses R12 as internal GOT pointer. r12
5917 is a volatile register so r12 needs to be reset when
5918 going back and forth between asm and C)
5920 ==> U-Boot will use R2 to hold a pointer to the global data
5922 Note: on PPC, we could use a static initializer (since the
5923 address of the global data structure is known at compile time),
5924 but it turned out that reserving a register results in somewhat
5925 smaller code - although the code savings are not that big (on
5926 average for all boards 752 bytes for the whole U-Boot image,
5927 624 text + 127 data).
5929 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5930 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5932 ==> U-Boot will use P3 to hold a pointer to the global data
5934 On ARM, the following registers are used:
5936 R0: function argument word/integer result
5937 R1-R3: function argument word
5938 R9: platform specific
5939 R10: stack limit (used only if stack checking is enabled)
5940 R11: argument (frame) pointer
5941 R12: temporary workspace
5944 R15: program counter
5946 ==> U-Boot will use R9 to hold a pointer to the global data
5948 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5950 On Nios II, the ABI is documented here:
5951 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5953 ==> U-Boot will use gp to hold a pointer to the global data
5955 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5956 to access small data sections, so gp is free.
5958 On NDS32, the following registers are used:
5960 R0-R1: argument/return
5962 R15: temporary register for assembler
5963 R16: trampoline register
5964 R28: frame pointer (FP)
5965 R29: global pointer (GP)
5966 R30: link register (LP)
5967 R31: stack pointer (SP)
5968 PC: program counter (PC)
5970 ==> U-Boot will use R10 to hold a pointer to the global data
5972 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5973 or current versions of GCC may "optimize" the code too much.
5978 U-Boot runs in system state and uses physical addresses, i.e. the
5979 MMU is not used either for address mapping nor for memory protection.
5981 The available memory is mapped to fixed addresses using the memory
5982 controller. In this process, a contiguous block is formed for each
5983 memory type (Flash, SDRAM, SRAM), even when it consists of several
5984 physical memory banks.
5986 U-Boot is installed in the first 128 kB of the first Flash bank (on
5987 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5988 booting and sizing and initializing DRAM, the code relocates itself
5989 to the upper end of DRAM. Immediately below the U-Boot code some
5990 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5991 configuration setting]. Below that, a structure with global Board
5992 Info data is placed, followed by the stack (growing downward).
5994 Additionally, some exception handler code is copied to the low 8 kB
5995 of DRAM (0x00000000 ... 0x00001FFF).
5997 So a typical memory configuration with 16 MB of DRAM could look like
6000 0x0000 0000 Exception Vector code
6003 0x0000 2000 Free for Application Use
6009 0x00FB FF20 Monitor Stack (Growing downward)
6010 0x00FB FFAC Board Info Data and permanent copy of global data
6011 0x00FC 0000 Malloc Arena
6014 0x00FE 0000 RAM Copy of Monitor Code
6015 ... eventually: LCD or video framebuffer
6016 ... eventually: pRAM (Protected RAM - unchanged by reset)
6017 0x00FF FFFF [End of RAM]
6020 System Initialization:
6021 ----------------------
6023 In the reset configuration, U-Boot starts at the reset entry point
6024 (on most PowerPC systems at address 0x00000100). Because of the reset
6025 configuration for CS0# this is a mirror of the onboard Flash memory.
6026 To be able to re-map memory U-Boot then jumps to its link address.
6027 To be able to implement the initialization code in C, a (small!)
6028 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6029 which provide such a feature like MPC8xx or MPC8260), or in a locked
6030 part of the data cache. After that, U-Boot initializes the CPU core,
6031 the caches and the SIU.
6033 Next, all (potentially) available memory banks are mapped using a
6034 preliminary mapping. For example, we put them on 512 MB boundaries
6035 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6036 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6037 programmed for SDRAM access. Using the temporary configuration, a
6038 simple memory test is run that determines the size of the SDRAM
6041 When there is more than one SDRAM bank, and the banks are of
6042 different size, the largest is mapped first. For equal size, the first
6043 bank (CS2#) is mapped first. The first mapping is always for address
6044 0x00000000, with any additional banks following immediately to create
6045 contiguous memory starting from 0.
6047 Then, the monitor installs itself at the upper end of the SDRAM area
6048 and allocates memory for use by malloc() and for the global Board
6049 Info data; also, the exception vector code is copied to the low RAM
6050 pages, and the final stack is set up.
6052 Only after this relocation will you have a "normal" C environment;
6053 until that you are restricted in several ways, mostly because you are
6054 running from ROM, and because the code will have to be relocated to a
6058 U-Boot Porting Guide:
6059 ----------------------
6061 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6065 int main(int argc, char *argv[])
6067 sighandler_t no_more_time;
6069 signal(SIGALRM, no_more_time);
6070 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6072 if (available_money > available_manpower) {
6073 Pay consultant to port U-Boot;
6077 Download latest U-Boot source;
6079 Subscribe to u-boot mailing list;
6082 email("Hi, I am new to U-Boot, how do I get started?");
6085 Read the README file in the top level directory;
6086 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6087 Read applicable doc/*.README;
6088 Read the source, Luke;
6089 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6092 if (available_money > toLocalCurrency ($2500))
6095 Add a lot of aggravation and time;
6097 if (a similar board exists) { /* hopefully... */
6098 cp -a board/<similar> board/<myboard>
6099 cp include/configs/<similar>.h include/configs/<myboard>.h
6101 Create your own board support subdirectory;
6102 Create your own board include/configs/<myboard>.h file;
6104 Edit new board/<myboard> files
6105 Edit new include/configs/<myboard>.h
6110 Add / modify source code;
6114 email("Hi, I am having problems...");
6116 Send patch file to the U-Boot email list;
6117 if (reasonable critiques)
6118 Incorporate improvements from email list code review;
6120 Defend code as written;
6126 void no_more_time (int sig)
6135 All contributions to U-Boot should conform to the Linux kernel
6136 coding style; see the file "Documentation/CodingStyle" and the script
6137 "scripts/Lindent" in your Linux kernel source directory.
6139 Source files originating from a different project (for example the
6140 MTD subsystem) are generally exempt from these guidelines and are not
6141 reformated to ease subsequent migration to newer versions of those
6144 Please note that U-Boot is implemented in C (and to some small parts in
6145 Assembler); no C++ is used, so please do not use C++ style comments (//)
6148 Please also stick to the following formatting rules:
6149 - remove any trailing white space
6150 - use TAB characters for indentation and vertical alignment, not spaces
6151 - make sure NOT to use DOS '\r\n' line feeds
6152 - do not add more than 2 consecutive empty lines to source files
6153 - do not add trailing empty lines to source files
6155 Submissions which do not conform to the standards may be returned
6156 with a request to reformat the changes.
6162 Since the number of patches for U-Boot is growing, we need to
6163 establish some rules. Submissions which do not conform to these rules
6164 may be rejected, even when they contain important and valuable stuff.
6166 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6168 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6169 see http://lists.denx.de/mailman/listinfo/u-boot
6171 When you send a patch, please include the following information with
6174 * For bug fixes: a description of the bug and how your patch fixes
6175 this bug. Please try to include a way of demonstrating that the
6176 patch actually fixes something.
6178 * For new features: a description of the feature and your
6181 * A CHANGELOG entry as plaintext (separate from the patch)
6183 * For major contributions, your entry to the CREDITS file
6185 * When you add support for a new board, don't forget to add a
6186 maintainer e-mail address to the boards.cfg file, too.
6188 * If your patch adds new configuration options, don't forget to
6189 document these in the README file.
6191 * The patch itself. If you are using git (which is *strongly*
6192 recommended) you can easily generate the patch using the
6193 "git format-patch". If you then use "git send-email" to send it to
6194 the U-Boot mailing list, you will avoid most of the common problems
6195 with some other mail clients.
6197 If you cannot use git, use "diff -purN OLD NEW". If your version of
6198 diff does not support these options, then get the latest version of
6201 The current directory when running this command shall be the parent
6202 directory of the U-Boot source tree (i. e. please make sure that
6203 your patch includes sufficient directory information for the
6206 We prefer patches as plain text. MIME attachments are discouraged,
6207 and compressed attachments must not be used.
6209 * If one logical set of modifications affects or creates several
6210 files, all these changes shall be submitted in a SINGLE patch file.
6212 * Changesets that contain different, unrelated modifications shall be
6213 submitted as SEPARATE patches, one patch per changeset.
6218 * Before sending the patch, run the MAKEALL script on your patched
6219 source tree and make sure that no errors or warnings are reported
6220 for any of the boards.
6222 * Keep your modifications to the necessary minimum: A patch
6223 containing several unrelated changes or arbitrary reformats will be
6224 returned with a request to re-formatting / split it.
6226 * If you modify existing code, make sure that your new code does not
6227 add to the memory footprint of the code ;-) Small is beautiful!
6228 When adding new features, these should compile conditionally only
6229 (using #ifdef), and the resulting code with the new feature
6230 disabled must not need more memory than the old code without your
6233 * Remember that there is a size limit of 100 kB per message on the
6234 u-boot mailing list. Bigger patches will be moderated. If they are
6235 reasonable and not too big, they will be acknowledged. But patches
6236 bigger than the size limit should be avoided.
projects / people / ms / u-boot.git / blob