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 - Marvell Family Member
325 CONFIG_SYS_MVFS - define it if you want to enable
326 multiple fs option at one time
327 for marvell soc family
329 - MPC824X Family Member (if CONFIG_MPC824X is defined)
330 Define exactly one of
331 CONFIG_MPC8240, CONFIG_MPC8245
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_PPC_E500_DEBUG_TLB
381 Enables a temporary TLB entry to be used during boot to work
382 around limitations in e500v1 and e500v2 external debugger
383 support. This reduces the portions of the boot code where
384 breakpoints and single stepping do not work. The value of this
385 symbol should be set to the TLB1 entry to be used for this
388 CONFIG_SYS_FSL_ERRATUM_A004510
390 Enables a workaround for erratum A004510. If set,
391 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
394 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
397 Defines one or two SoC revisions (low 8 bits of SVR)
398 for which the A004510 workaround should be applied.
400 The rest of SVR is either not relevant to the decision
401 of whether the erratum is present (e.g. p2040 versus
402 p2041) or is implied by the build target, which controls
403 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
405 See Freescale App Note 4493 for more information about
408 CONFIG_A003399_NOR_WORKAROUND
409 Enables a workaround for IFC erratum A003399. It is only
410 requred during NOR boot.
412 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
414 This is the value to write into CCSR offset 0x18600
415 according to the A004510 workaround.
417 CONFIG_SYS_FSL_DSP_DDR_ADDR
418 This value denotes start offset of DDR memory which is
419 connected exclusively to the DSP cores.
421 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
422 This value denotes start offset of M2 memory
423 which is directly connected to the DSP core.
425 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
426 This value denotes start offset of M3 memory which is directly
427 connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430 This value denotes start offset of DSP CCSR space.
432 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
433 Single Source Clock is clocking mode present in some of FSL SoC's.
434 In this mode, a single differential clock is used to supply
435 clocks to the sysclock, ddrclock and usbclock.
437 CONFIG_SYS_CPC_REINIT_F
438 This CONFIG is defined when the CPC is configured as SRAM at the
439 time of U-boot entry and is required to be re-initialized.
442 Inidcates this SoC supports deep sleep feature. If deep sleep is
443 supported, core will start to execute uboot when wakes up.
445 - Generic CPU options:
446 CONFIG_SYS_GENERIC_GLOBAL_DATA
447 Defines global data is initialized in generic board board_init_f().
448 If this macro is defined, global data is created and cleared in
449 generic board board_init_f(). Without this macro, architecture/board
450 should initialize global data before calling board_init_f().
452 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
454 Defines the endianess of the CPU. Implementation of those
455 values is arch specific.
458 Freescale DDR driver in use. This type of DDR controller is
459 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
462 CONFIG_SYS_FSL_DDR_ADDR
463 Freescale DDR memory-mapped register base.
465 CONFIG_SYS_FSL_DDR_EMU
466 Specify emulator support for DDR. Some DDR features such as
467 deskew training are not available.
469 CONFIG_SYS_FSL_DDRC_GEN1
470 Freescale DDR1 controller.
472 CONFIG_SYS_FSL_DDRC_GEN2
473 Freescale DDR2 controller.
475 CONFIG_SYS_FSL_DDRC_GEN3
476 Freescale DDR3 controller.
478 CONFIG_SYS_FSL_DDRC_GEN4
479 Freescale DDR4 controller.
481 CONFIG_SYS_FSL_DDRC_ARM_GEN3
482 Freescale DDR3 controller for ARM-based SoCs.
485 Board config to use DDR1. It can be enabled for SoCs with
486 Freescale DDR1 or DDR2 controllers, depending on the board
490 Board config to use DDR2. It can be eanbeld for SoCs with
491 Freescale DDR2 or DDR3 controllers, depending on the board
495 Board config to use DDR3. It can be enabled for SoCs with
496 Freescale DDR3 or DDR3L controllers.
499 Board config to use DDR3L. It can be enabled for SoCs with
503 Board config to use DDR4. It can be enabled for SoCs with
506 CONFIG_SYS_FSL_IFC_BE
507 Defines the IFC controller register space as Big Endian
509 CONFIG_SYS_FSL_IFC_LE
510 Defines the IFC controller register space as Little Endian
512 CONFIG_SYS_FSL_PBL_PBI
513 It enables addition of RCW (Power on reset configuration) in built image.
514 Please refer doc/README.pblimage for more details
516 CONFIG_SYS_FSL_PBL_RCW
517 It adds PBI(pre-boot instructions) commands in u-boot build image.
518 PBI commands can be used to configure SoC before it starts the execution.
519 Please refer doc/README.pblimage for more details
522 It adds a target to create boot binary having SPL binary in PBI format
523 concatenated with u-boot binary.
525 CONFIG_SYS_FSL_DDR_BE
526 Defines the DDR controller register space as Big Endian
528 CONFIG_SYS_FSL_DDR_LE
529 Defines the DDR controller register space as Little Endian
531 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532 Physical address from the view of DDR controllers. It is the
533 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
534 it could be different for ARM SoCs.
536 CONFIG_SYS_FSL_DDR_INTLV_256B
537 DDR controller interleaving on 256-byte. This is a special
538 interleaving mode, handled by Dickens for Freescale layerscape
541 - Intel Monahans options:
542 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
544 Defines the Monahans run mode to oscillator
545 ratio. Valid values are 8, 16, 24, 31. The core
546 frequency is this value multiplied by 13 MHz.
548 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
550 Defines the Monahans turbo mode to oscillator
551 ratio. Valid values are 1 (default if undefined) and
552 2. The core frequency as calculated above is multiplied
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
593 CONFIG_SYS_THUMB_BUILD
595 Use this flag to build U-Boot using the Thumb instruction
596 set for ARM architectures. Thumb instruction set provides
597 better code density. For ARM architectures that support
598 Thumb2 this flag will result in Thumb2 code generated by
601 CONFIG_ARM_ERRATA_716044
602 CONFIG_ARM_ERRATA_742230
603 CONFIG_ARM_ERRATA_743622
604 CONFIG_ARM_ERRATA_751472
605 CONFIG_ARM_ERRATA_794072
606 CONFIG_ARM_ERRATA_761320
608 If set, the workarounds for these ARM errata are applied early
609 during U-Boot startup. Note that these options force the
610 workarounds to be applied; no CPU-type/version detection
611 exists, unlike the similar options in the Linux kernel. Do not
612 set these options unless they apply!
617 The frequency of the timer returned by get_timer().
618 get_timer() must operate in milliseconds and this CONFIG
619 option must be set to 1000.
621 - Linux Kernel Interface:
624 U-Boot stores all clock information in Hz
625 internally. For binary compatibility with older Linux
626 kernels (which expect the clocks passed in the
627 bd_info data to be in MHz) the environment variable
628 "clocks_in_mhz" can be defined so that U-Boot
629 converts clock data to MHZ before passing it to the
631 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
632 "clocks_in_mhz=1" is automatically included in the
635 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
637 When transferring memsize parameter to linux, some versions
638 expect it to be in bytes, others in MB.
639 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
643 New kernel versions are expecting firmware settings to be
644 passed using flattened device trees (based on open firmware
648 * New libfdt-based support
649 * Adds the "fdt" command
650 * The bootm command automatically updates the fdt
652 OF_CPU - The proper name of the cpus node (only required for
653 MPC512X and MPC5xxx based boards).
654 OF_SOC - The proper name of the soc node (only required for
655 MPC512X and MPC5xxx based boards).
656 OF_TBCLK - The timebase frequency.
657 OF_STDOUT_PATH - The path to the console device
659 boards with QUICC Engines require OF_QE to set UCC MAC
662 CONFIG_OF_BOARD_SETUP
664 Board code has addition modification that it wants to make
665 to the flat device tree before handing it off to the kernel
669 This define fills in the correct boot CPU in the boot
670 param header, the default value is zero if undefined.
674 U-Boot can detect if an IDE device is present or not.
675 If not, and this new config option is activated, U-Boot
676 removes the ATA node from the DTS before booting Linux,
677 so the Linux IDE driver does not probe the device and
678 crash. This is needed for buggy hardware (uc101) where
679 no pull down resistor is connected to the signal IDE5V_DD7.
681 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
683 This setting is mandatory for all boards that have only one
684 machine type and must be used to specify the machine type
685 number as it appears in the ARM machine registry
686 (see http://www.arm.linux.org.uk/developer/machines/).
687 Only boards that have multiple machine types supported
688 in a single configuration file and the machine type is
689 runtime discoverable, do not have to use this setting.
691 - vxWorks boot parameters:
693 bootvx constructs a valid bootline using the following
694 environments variables: bootfile, ipaddr, serverip, hostname.
695 It loads the vxWorks image pointed bootfile.
697 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
698 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
699 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
700 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
702 CONFIG_SYS_VXWORKS_ADD_PARAMS
704 Add it at the end of the bootline. E.g "u=username pw=secret"
706 Note: If a "bootargs" environment is defined, it will overwride
707 the defaults discussed just above.
709 - Cache Configuration:
710 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
711 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
712 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
714 - Cache Configuration for ARM:
715 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
717 CONFIG_SYS_PL310_BASE - Physical base address of PL310
718 controller register space
723 Define this if you want support for Amba PrimeCell PL010 UARTs.
727 Define this if you want support for Amba PrimeCell PL011 UARTs.
731 If you have Amba PrimeCell PL011 UARTs, set this variable to
732 the clock speed of the UARTs.
736 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
737 define this to a list of base addresses for each (supported)
738 port. See e.g. include/configs/versatile.h
740 CONFIG_PL011_SERIAL_RLCR
742 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
743 have separate receive and transmit line control registers. Set
744 this variable to initialize the extra register.
746 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
748 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
749 boot loader that has already initialized the UART. Define this
750 variable to flush the UART at init time.
752 CONFIG_SERIAL_HW_FLOW_CONTROL
754 Define this variable to enable hw flow control in serial driver.
755 Current user of this option is drivers/serial/nsl16550.c driver
758 Depending on board, define exactly one serial port
759 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
760 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
761 console by defining CONFIG_8xx_CONS_NONE
763 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
764 port routines must be defined elsewhere
765 (i.e. serial_init(), serial_getc(), ...)
768 Enables console device for a color framebuffer. Needs following
769 defines (cf. smiLynxEM, i8042)
770 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
772 VIDEO_HW_RECTFILL graphic chip supports
775 VIDEO_HW_BITBLT graphic chip supports
776 bit-blit (cf. smiLynxEM)
777 VIDEO_VISIBLE_COLS visible pixel columns
779 VIDEO_VISIBLE_ROWS visible pixel rows
780 VIDEO_PIXEL_SIZE bytes per pixel
781 VIDEO_DATA_FORMAT graphic data format
782 (0-5, cf. cfb_console.c)
783 VIDEO_FB_ADRS framebuffer address
784 VIDEO_KBD_INIT_FCT keyboard int fct
785 (i.e. i8042_kbd_init())
786 VIDEO_TSTC_FCT test char fct
788 VIDEO_GETC_FCT get char fct
790 CONFIG_CONSOLE_CURSOR cursor drawing on/off
791 (requires blink timer
793 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
794 CONFIG_CONSOLE_TIME display time/date info in
796 (requires CONFIG_CMD_DATE)
797 CONFIG_VIDEO_LOGO display Linux logo in
799 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
800 linux_logo.h for logo.
801 Requires CONFIG_VIDEO_LOGO
802 CONFIG_CONSOLE_EXTRA_INFO
803 additional board info beside
806 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
807 a limited number of ANSI escape sequences (cursor control,
808 erase functions and limited graphics rendition control).
810 When CONFIG_CFB_CONSOLE is defined, video console is
811 default i/o. Serial console can be forced with
812 environment 'console=serial'.
814 When CONFIG_SILENT_CONSOLE is defined, all console
815 messages (by U-Boot and Linux!) can be silenced with
816 the "silent" environment variable. See
817 doc/README.silent for more information.
819 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
821 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
825 CONFIG_BAUDRATE - in bps
826 Select one of the baudrates listed in
827 CONFIG_SYS_BAUDRATE_TABLE, see below.
828 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
830 - Console Rx buffer length
831 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
832 the maximum receive buffer length for the SMC.
833 This option is actual only for 82xx and 8xx possible.
834 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
835 must be defined, to setup the maximum idle timeout for
838 - Pre-Console Buffer:
839 Prior to the console being initialised (i.e. serial UART
840 initialised etc) all console output is silently discarded.
841 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
842 buffer any console messages prior to the console being
843 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
844 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
845 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
846 bytes are output before the console is initialised, the
847 earlier bytes are discarded.
849 'Sane' compilers will generate smaller code if
850 CONFIG_PRE_CON_BUF_SZ is a power of 2
852 - Safe printf() functions
853 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
854 the printf() functions. These are defined in
855 include/vsprintf.h and include snprintf(), vsnprintf() and
856 so on. Code size increase is approximately 300-500 bytes.
857 If this option is not given then these functions will
858 silently discard their buffer size argument - this means
859 you are not getting any overflow checking in this case.
861 - Boot Delay: CONFIG_BOOTDELAY - in seconds
862 Delay before automatically booting the default image;
863 set to -1 to disable autoboot.
864 set to -2 to autoboot with no delay and not check for abort
865 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
867 See doc/README.autoboot for these options that
868 work with CONFIG_BOOTDELAY. None are required.
869 CONFIG_BOOT_RETRY_TIME
870 CONFIG_BOOT_RETRY_MIN
871 CONFIG_AUTOBOOT_KEYED
872 CONFIG_AUTOBOOT_PROMPT
873 CONFIG_AUTOBOOT_DELAY_STR
874 CONFIG_AUTOBOOT_STOP_STR
875 CONFIG_AUTOBOOT_DELAY_STR2
876 CONFIG_AUTOBOOT_STOP_STR2
877 CONFIG_ZERO_BOOTDELAY_CHECK
878 CONFIG_RESET_TO_RETRY
882 Only needed when CONFIG_BOOTDELAY is enabled;
883 define a command string that is automatically executed
884 when no character is read on the console interface
885 within "Boot Delay" after reset.
888 This can be used to pass arguments to the bootm
889 command. The value of CONFIG_BOOTARGS goes into the
890 environment value "bootargs".
892 CONFIG_RAMBOOT and CONFIG_NFSBOOT
893 The value of these goes into the environment as
894 "ramboot" and "nfsboot" respectively, and can be used
895 as a convenience, when switching between booting from
899 CONFIG_BOOTCOUNT_LIMIT
900 Implements a mechanism for detecting a repeating reboot
902 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
905 If no softreset save registers are found on the hardware
906 "bootcount" is stored in the environment. To prevent a
907 saveenv on all reboots, the environment variable
908 "upgrade_available" is used. If "upgrade_available" is
909 0, "bootcount" is always 0, if "upgrade_available" is
910 1 "bootcount" is incremented in the environment.
911 So the Userspace Applikation must set the "upgrade_available"
912 and "bootcount" variable to 0, if a boot was successfully.
917 When this option is #defined, the existence of the
918 environment variable "preboot" will be checked
919 immediately before starting the CONFIG_BOOTDELAY
920 countdown and/or running the auto-boot command resp.
921 entering interactive mode.
923 This feature is especially useful when "preboot" is
924 automatically generated or modified. For an example
925 see the LWMON board specific code: here "preboot" is
926 modified when the user holds down a certain
927 combination of keys on the (special) keyboard when
930 - Serial Download Echo Mode:
932 If defined to 1, all characters received during a
933 serial download (using the "loads" command) are
934 echoed back. This might be needed by some terminal
935 emulations (like "cu"), but may as well just take
936 time on others. This setting #define's the initial
937 value of the "loads_echo" environment variable.
939 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
941 Select one of the baudrates listed in
942 CONFIG_SYS_BAUDRATE_TABLE, see below.
945 Monitor commands can be included or excluded
946 from the build by using the #include files
947 <config_cmd_all.h> and #undef'ing unwanted
948 commands, or using <config_cmd_default.h>
949 and augmenting with additional #define's
952 The default command configuration includes all commands
953 except those marked below with a "*".
955 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
956 CONFIG_CMD_ASKENV * ask for env variable
957 CONFIG_CMD_BDI bdinfo
958 CONFIG_CMD_BEDBUG * Include BedBug Debugger
959 CONFIG_CMD_BMP * BMP support
960 CONFIG_CMD_BSP * Board specific commands
961 CONFIG_CMD_BOOTD bootd
962 CONFIG_CMD_CACHE * icache, dcache
963 CONFIG_CMD_CLK * clock command support
964 CONFIG_CMD_CONSOLE coninfo
965 CONFIG_CMD_CRC32 * crc32
966 CONFIG_CMD_DATE * support for RTC, date/time...
967 CONFIG_CMD_DHCP * DHCP support
968 CONFIG_CMD_DIAG * Diagnostics
969 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
970 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
971 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
972 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
973 CONFIG_CMD_DTT * Digital Therm and Thermostat
974 CONFIG_CMD_ECHO echo arguments
975 CONFIG_CMD_EDITENV edit env variable
976 CONFIG_CMD_EEPROM * EEPROM read/write support
977 CONFIG_CMD_ELF * bootelf, bootvx
978 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
979 CONFIG_CMD_ENV_FLAGS * display details about env flags
980 CONFIG_CMD_ENV_EXISTS * check existence of env variable
981 CONFIG_CMD_EXPORTENV * export the environment
982 CONFIG_CMD_EXT2 * ext2 command support
983 CONFIG_CMD_EXT4 * ext4 command support
984 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
985 that work for multiple fs types
986 CONFIG_CMD_SAVEENV saveenv
987 CONFIG_CMD_FDC * Floppy Disk Support
988 CONFIG_CMD_FAT * FAT command support
989 CONFIG_CMD_FLASH flinfo, erase, protect
990 CONFIG_CMD_FPGA FPGA device initialization support
991 CONFIG_CMD_FUSE * Device fuse support
992 CONFIG_CMD_GETTIME * Get time since boot
993 CONFIG_CMD_GO * the 'go' command (exec code)
994 CONFIG_CMD_GREPENV * search environment
995 CONFIG_CMD_HASH * calculate hash / digest
996 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
997 CONFIG_CMD_I2C * I2C serial bus support
998 CONFIG_CMD_IDE * IDE harddisk support
999 CONFIG_CMD_IMI iminfo
1000 CONFIG_CMD_IMLS List all images found in NOR flash
1001 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1002 CONFIG_CMD_IMMAP * IMMR dump support
1003 CONFIG_CMD_IMPORTENV * import an environment
1004 CONFIG_CMD_INI * import data from an ini file into the env
1005 CONFIG_CMD_IRQ * irqinfo
1006 CONFIG_CMD_ITEST Integer/string test of 2 values
1007 CONFIG_CMD_JFFS2 * JFFS2 Support
1008 CONFIG_CMD_KGDB * kgdb
1009 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1010 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1012 CONFIG_CMD_LOADB loadb
1013 CONFIG_CMD_LOADS loads
1014 CONFIG_CMD_MD5SUM * print md5 message digest
1015 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1016 CONFIG_CMD_MEMINFO * Display detailed memory information
1017 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1019 CONFIG_CMD_MEMTEST * mtest
1020 CONFIG_CMD_MISC Misc functions like sleep etc
1021 CONFIG_CMD_MMC * MMC memory mapped support
1022 CONFIG_CMD_MII * MII utility commands
1023 CONFIG_CMD_MTDPARTS * MTD partition support
1024 CONFIG_CMD_NAND * NAND support
1025 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1026 CONFIG_CMD_NFS NFS support
1027 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1028 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1029 CONFIG_CMD_PCI * pciinfo
1030 CONFIG_CMD_PCMCIA * PCMCIA support
1031 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1033 CONFIG_CMD_PORTIO * Port I/O
1034 CONFIG_CMD_READ * Read raw data from partition
1035 CONFIG_CMD_REGINFO * Register dump
1036 CONFIG_CMD_RUN run command in env variable
1037 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1038 CONFIG_CMD_SAVES * save S record dump
1039 CONFIG_CMD_SCSI * SCSI Support
1040 CONFIG_CMD_SDRAM * print SDRAM configuration information
1041 (requires CONFIG_CMD_I2C)
1042 CONFIG_CMD_SETGETDCR Support for DCR Register access
1044 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1045 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1046 (requires CONFIG_CMD_MEMORY)
1047 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1048 CONFIG_CMD_SOURCE "source" command Support
1049 CONFIG_CMD_SPI * SPI serial bus support
1050 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1051 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1052 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1053 CONFIG_CMD_TIMER * access to the system tick timer
1054 CONFIG_CMD_USB * USB support
1055 CONFIG_CMD_CDP * Cisco Discover Protocol support
1056 CONFIG_CMD_MFSL * Microblaze FSL support
1057 CONFIG_CMD_XIMG Load part of Multi Image
1058 CONFIG_CMD_UUID * Generate random UUID or GUID string
1060 EXAMPLE: If you want all functions except of network
1061 support you can write:
1063 #include "config_cmd_all.h"
1064 #undef CONFIG_CMD_NET
1067 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1069 Note: Don't enable the "icache" and "dcache" commands
1070 (configuration option CONFIG_CMD_CACHE) unless you know
1071 what you (and your U-Boot users) are doing. Data
1072 cache cannot be enabled on systems like the 8xx or
1073 8260 (where accesses to the IMMR region must be
1074 uncached), and it cannot be disabled on all other
1075 systems where we (mis-) use the data cache to hold an
1076 initial stack and some data.
1079 XXX - this list needs to get updated!
1081 - Regular expression support:
1083 If this variable is defined, U-Boot is linked against
1084 the SLRE (Super Light Regular Expression) library,
1085 which adds regex support to some commands, as for
1086 example "env grep" and "setexpr".
1090 If this variable is defined, U-Boot will use a device tree
1091 to configure its devices, instead of relying on statically
1092 compiled #defines in the board file. This option is
1093 experimental and only available on a few boards. The device
1094 tree is available in the global data as gd->fdt_blob.
1096 U-Boot needs to get its device tree from somewhere. This can
1097 be done using one of the two options below:
1100 If this variable is defined, U-Boot will embed a device tree
1101 binary in its image. This device tree file should be in the
1102 board directory and called <soc>-<board>.dts. The binary file
1103 is then picked up in board_init_f() and made available through
1104 the global data structure as gd->blob.
1107 If this variable is defined, U-Boot will build a device tree
1108 binary. It will be called u-boot.dtb. Architecture-specific
1109 code will locate it at run-time. Generally this works by:
1111 cat u-boot.bin u-boot.dtb >image.bin
1113 and in fact, U-Boot does this for you, creating a file called
1114 u-boot-dtb.bin which is useful in the common case. You can
1115 still use the individual files if you need something more
1120 If this variable is defined, it enables watchdog
1121 support for the SoC. There must be support in the SoC
1122 specific code for a watchdog. For the 8xx and 8260
1123 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1124 register. When supported for a specific SoC is
1125 available, then no further board specific code should
1126 be needed to use it.
1129 When using a watchdog circuitry external to the used
1130 SoC, then define this variable and provide board
1131 specific code for the "hw_watchdog_reset" function.
1134 CONFIG_VERSION_VARIABLE
1135 If this variable is defined, an environment variable
1136 named "ver" is created by U-Boot showing the U-Boot
1137 version as printed by the "version" command.
1138 Any change to this variable will be reverted at the
1143 When CONFIG_CMD_DATE is selected, the type of the RTC
1144 has to be selected, too. Define exactly one of the
1147 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1148 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1149 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1150 CONFIG_RTC_MC146818 - use MC146818 RTC
1151 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1152 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1153 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1154 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1155 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1156 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1157 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1158 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1161 Note that if the RTC uses I2C, then the I2C interface
1162 must also be configured. See I2C Support, below.
1165 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1167 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1168 chip-ngpio pairs that tell the PCA953X driver the number of
1169 pins supported by a particular chip.
1171 Note that if the GPIO device uses I2C, then the I2C interface
1172 must also be configured. See I2C Support, below.
1174 - Timestamp Support:
1176 When CONFIG_TIMESTAMP is selected, the timestamp
1177 (date and time) of an image is printed by image
1178 commands like bootm or iminfo. This option is
1179 automatically enabled when you select CONFIG_CMD_DATE .
1181 - Partition Labels (disklabels) Supported:
1182 Zero or more of the following:
1183 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1184 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1185 Intel architecture, USB sticks, etc.
1186 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1187 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1188 bootloader. Note 2TB partition limit; see
1190 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1192 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1193 CONFIG_CMD_SCSI) you must configure support for at
1194 least one non-MTD partition type as well.
1197 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1198 board configurations files but used nowhere!
1200 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1201 be performed by calling the function
1202 ide_set_reset(int reset)
1203 which has to be defined in a board specific file
1208 Set this to enable ATAPI support.
1213 Set this to enable support for disks larger than 137GB
1214 Also look at CONFIG_SYS_64BIT_LBA.
1215 Whithout these , LBA48 support uses 32bit variables and will 'only'
1216 support disks up to 2.1TB.
1218 CONFIG_SYS_64BIT_LBA:
1219 When enabled, makes the IDE subsystem use 64bit sector addresses.
1223 At the moment only there is only support for the
1224 SYM53C8XX SCSI controller; define
1225 CONFIG_SCSI_SYM53C8XX to enable it.
1227 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1228 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1229 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1230 maximum numbers of LUNs, SCSI ID's and target
1232 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1234 The environment variable 'scsidevs' is set to the number of
1235 SCSI devices found during the last scan.
1237 - NETWORK Support (PCI):
1239 Support for Intel 8254x/8257x gigabit chips.
1242 Utility code for direct access to the SPI bus on Intel 8257x.
1243 This does not do anything useful unless you set at least one
1244 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1246 CONFIG_E1000_SPI_GENERIC
1247 Allow generic access to the SPI bus on the Intel 8257x, for
1248 example with the "sspi" command.
1251 Management command for E1000 devices. When used on devices
1252 with SPI support you can reprogram the EEPROM from U-Boot.
1254 CONFIG_E1000_FALLBACK_MAC
1255 default MAC for empty EEPROM after production.
1258 Support for Intel 82557/82559/82559ER chips.
1259 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1260 write routine for first time initialisation.
1263 Support for Digital 2114x chips.
1264 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1265 modem chip initialisation (KS8761/QS6611).
1268 Support for National dp83815 chips.
1271 Support for National dp8382[01] gigabit chips.
1273 - NETWORK Support (other):
1275 CONFIG_DRIVER_AT91EMAC
1276 Support for AT91RM9200 EMAC.
1279 Define this to use reduced MII inteface
1281 CONFIG_DRIVER_AT91EMAC_QUIET
1282 If this defined, the driver is quiet.
1283 The driver doen't show link status messages.
1285 CONFIG_CALXEDA_XGMAC
1286 Support for the Calxeda XGMAC device
1289 Support for SMSC's LAN91C96 chips.
1291 CONFIG_LAN91C96_BASE
1292 Define this to hold the physical address
1293 of the LAN91C96's I/O space
1295 CONFIG_LAN91C96_USE_32_BIT
1296 Define this to enable 32 bit addressing
1299 Support for SMSC's LAN91C111 chip
1301 CONFIG_SMC91111_BASE
1302 Define this to hold the physical address
1303 of the device (I/O space)
1305 CONFIG_SMC_USE_32_BIT
1306 Define this if data bus is 32 bits
1308 CONFIG_SMC_USE_IOFUNCS
1309 Define this to use i/o functions instead of macros
1310 (some hardware wont work with macros)
1312 CONFIG_DRIVER_TI_EMAC
1313 Support for davinci emac
1315 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1316 Define this if you have more then 3 PHYs.
1319 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1321 CONFIG_FTGMAC100_EGIGA
1322 Define this to use GE link update with gigabit PHY.
1323 Define this if FTGMAC100 is connected to gigabit PHY.
1324 If your system has 10/100 PHY only, it might not occur
1325 wrong behavior. Because PHY usually return timeout or
1326 useless data when polling gigabit status and gigabit
1327 control registers. This behavior won't affect the
1328 correctnessof 10/100 link speed update.
1331 Support for SMSC's LAN911x and LAN921x chips
1334 Define this to hold the physical address
1335 of the device (I/O space)
1337 CONFIG_SMC911X_32_BIT
1338 Define this if data bus is 32 bits
1340 CONFIG_SMC911X_16_BIT
1341 Define this if data bus is 16 bits. If your processor
1342 automatically converts one 32 bit word to two 16 bit
1343 words you may also try CONFIG_SMC911X_32_BIT.
1346 Support for Renesas on-chip Ethernet controller
1348 CONFIG_SH_ETHER_USE_PORT
1349 Define the number of ports to be used
1351 CONFIG_SH_ETHER_PHY_ADDR
1352 Define the ETH PHY's address
1354 CONFIG_SH_ETHER_CACHE_WRITEBACK
1355 If this option is set, the driver enables cache flush.
1359 Support TPM devices.
1362 Support for i2c bus TPM devices. Only one device
1363 per system is supported at this time.
1365 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1366 Define the the i2c bus number for the TPM device
1368 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1369 Define the TPM's address on the i2c bus
1371 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1372 Define the burst count bytes upper limit
1374 CONFIG_TPM_ATMEL_TWI
1375 Support for Atmel TWI TPM device. Requires I2C support.
1378 Support for generic parallel port TPM devices. Only one device
1379 per system is supported at this time.
1381 CONFIG_TPM_TIS_BASE_ADDRESS
1382 Base address where the generic TPM device is mapped
1383 to. Contemporary x86 systems usually map it at
1387 Add tpm monitor functions.
1388 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1389 provides monitor access to authorized functions.
1392 Define this to enable the TPM support library which provides
1393 functional interfaces to some TPM commands.
1394 Requires support for a TPM device.
1396 CONFIG_TPM_AUTH_SESSIONS
1397 Define this to enable authorized functions in the TPM library.
1398 Requires CONFIG_TPM and CONFIG_SHA1.
1401 At the moment only the UHCI host controller is
1402 supported (PIP405, MIP405, MPC5200); define
1403 CONFIG_USB_UHCI to enable it.
1404 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1405 and define CONFIG_USB_STORAGE to enable the USB
1408 Supported are USB Keyboards and USB Floppy drives
1410 MPC5200 USB requires additional defines:
1412 for 528 MHz Clock: 0x0001bbbb
1416 for differential drivers: 0x00001000
1417 for single ended drivers: 0x00005000
1418 for differential drivers on PSC3: 0x00000100
1419 for single ended drivers on PSC3: 0x00004100
1420 CONFIG_SYS_USB_EVENT_POLL
1421 May be defined to allow interrupt polling
1422 instead of using asynchronous interrupts
1424 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1425 txfilltuning field in the EHCI controller on reset.
1427 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1428 interval for usb hub power-on delay.(minimum 100msec)
1431 Define the below if you wish to use the USB console.
1432 Once firmware is rebuilt from a serial console issue the
1433 command "setenv stdin usbtty; setenv stdout usbtty" and
1434 attach your USB cable. The Unix command "dmesg" should print
1435 it has found a new device. The environment variable usbtty
1436 can be set to gserial or cdc_acm to enable your device to
1437 appear to a USB host as a Linux gserial device or a
1438 Common Device Class Abstract Control Model serial device.
1439 If you select usbtty = gserial you should be able to enumerate
1441 # modprobe usbserial vendor=0xVendorID product=0xProductID
1442 else if using cdc_acm, simply setting the environment
1443 variable usbtty to be cdc_acm should suffice. The following
1444 might be defined in YourBoardName.h
1447 Define this to build a UDC device
1450 Define this to have a tty type of device available to
1451 talk to the UDC device
1454 Define this to enable the high speed support for usb
1455 device and usbtty. If this feature is enabled, a routine
1456 int is_usbd_high_speed(void)
1457 also needs to be defined by the driver to dynamically poll
1458 whether the enumeration has succeded at high speed or full
1461 CONFIG_SYS_CONSOLE_IS_IN_ENV
1462 Define this if you want stdin, stdout &/or stderr to
1466 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1467 Derive USB clock from external clock "blah"
1468 - CONFIG_SYS_USB_EXTC_CLK 0x02
1470 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1471 Derive USB clock from brgclk
1472 - CONFIG_SYS_USB_BRG_CLK 0x04
1474 If you have a USB-IF assigned VendorID then you may wish to
1475 define your own vendor specific values either in BoardName.h
1476 or directly in usbd_vendor_info.h. If you don't define
1477 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1478 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1479 should pretend to be a Linux device to it's target host.
1481 CONFIG_USBD_MANUFACTURER
1482 Define this string as the name of your company for
1483 - CONFIG_USBD_MANUFACTURER "my company"
1485 CONFIG_USBD_PRODUCT_NAME
1486 Define this string as the name of your product
1487 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1489 CONFIG_USBD_VENDORID
1490 Define this as your assigned Vendor ID from the USB
1491 Implementors Forum. This *must* be a genuine Vendor ID
1492 to avoid polluting the USB namespace.
1493 - CONFIG_USBD_VENDORID 0xFFFF
1495 CONFIG_USBD_PRODUCTID
1496 Define this as the unique Product ID
1498 - CONFIG_USBD_PRODUCTID 0xFFFF
1500 - ULPI Layer Support:
1501 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1502 the generic ULPI layer. The generic layer accesses the ULPI PHY
1503 via the platform viewport, so you need both the genric layer and
1504 the viewport enabled. Currently only Chipidea/ARC based
1505 viewport is supported.
1506 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1507 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1508 If your ULPI phy needs a different reference clock than the
1509 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1510 the appropriate value in Hz.
1513 The MMC controller on the Intel PXA is supported. To
1514 enable this define CONFIG_MMC. The MMC can be
1515 accessed from the boot prompt by mapping the device
1516 to physical memory similar to flash. Command line is
1517 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1518 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1521 Support for Renesas on-chip MMCIF controller
1523 CONFIG_SH_MMCIF_ADDR
1524 Define the base address of MMCIF registers
1527 Define the clock frequency for MMCIF
1530 Enable the generic MMC driver
1532 CONFIG_SUPPORT_EMMC_BOOT
1533 Enable some additional features of the eMMC boot partitions.
1535 CONFIG_SUPPORT_EMMC_RPMB
1536 Enable the commands for reading, writing and programming the
1537 key for the Replay Protection Memory Block partition in eMMC.
1539 - USB Device Firmware Update (DFU) class support:
1541 This enables the USB portion of the DFU USB class
1544 This enables the command "dfu" which is used to have
1545 U-Boot create a DFU class device via USB. This command
1546 requires that the "dfu_alt_info" environment variable be
1547 set and define the alt settings to expose to the host.
1550 This enables support for exposing (e)MMC devices via DFU.
1553 This enables support for exposing NAND devices via DFU.
1556 This enables support for exposing RAM via DFU.
1557 Note: DFU spec refer to non-volatile memory usage, but
1558 allow usages beyond the scope of spec - here RAM usage,
1559 one that would help mostly the developer.
1561 CONFIG_SYS_DFU_DATA_BUF_SIZE
1562 Dfu transfer uses a buffer before writing data to the
1563 raw storage device. Make the size (in bytes) of this buffer
1564 configurable. The size of this buffer is also configurable
1565 through the "dfu_bufsiz" environment variable.
1567 CONFIG_SYS_DFU_MAX_FILE_SIZE
1568 When updating files rather than the raw storage device,
1569 we use a static buffer to copy the file into and then write
1570 the buffer once we've been given the whole file. Define
1571 this to the maximum filesize (in bytes) for the buffer.
1572 Default is 4 MiB if undefined.
1574 DFU_DEFAULT_POLL_TIMEOUT
1575 Poll timeout [ms], is the timeout a device can send to the
1576 host. The host must wait for this timeout before sending
1577 a subsequent DFU_GET_STATUS request to the device.
1579 DFU_MANIFEST_POLL_TIMEOUT
1580 Poll timeout [ms], which the device sends to the host when
1581 entering dfuMANIFEST state. Host waits this timeout, before
1582 sending again an USB request to the device.
1584 - USB Device Android Fastboot support:
1586 This enables the command "fastboot" which enables the Android
1587 fastboot mode for the platform's USB device. Fastboot is a USB
1588 protocol for downloading images, flashing and device control
1589 used on Android devices.
1590 See doc/README.android-fastboot for more information.
1592 CONFIG_ANDROID_BOOT_IMAGE
1593 This enables support for booting images which use the Android
1594 image format header.
1596 CONFIG_USB_FASTBOOT_BUF_ADDR
1597 The fastboot protocol requires a large memory buffer for
1598 downloads. Define this to the starting RAM address to use for
1601 CONFIG_USB_FASTBOOT_BUF_SIZE
1602 The fastboot protocol requires a large memory buffer for
1603 downloads. This buffer should be as large as possible for a
1604 platform. Define this to the size available RAM for fastboot.
1606 - Journaling Flash filesystem support:
1607 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1608 CONFIG_JFFS2_NAND_DEV
1609 Define these for a default partition on a NAND device
1611 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1612 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1613 Define these for a default partition on a NOR device
1615 CONFIG_SYS_JFFS_CUSTOM_PART
1616 Define this to create an own partition. You have to provide a
1617 function struct part_info* jffs2_part_info(int part_num)
1619 If you define only one JFFS2 partition you may also want to
1620 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1621 to disable the command chpart. This is the default when you
1622 have not defined a custom partition
1624 - FAT(File Allocation Table) filesystem write function support:
1627 Define this to enable support for saving memory data as a
1628 file in FAT formatted partition.
1630 This will also enable the command "fatwrite" enabling the
1631 user to write files to FAT.
1633 CBFS (Coreboot Filesystem) support
1636 Define this to enable support for reading from a Coreboot
1637 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1643 Define this to enable standard (PC-Style) keyboard
1647 Standard PC keyboard driver with US (is default) and
1648 GERMAN key layout (switch via environment 'keymap=de') support.
1649 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1650 for cfb_console. Supports cursor blinking.
1653 Enables a Chrome OS keyboard using the CROS_EC interface.
1654 This uses CROS_EC to communicate with a second microcontroller
1655 which provides key scans on request.
1660 Define this to enable video support (for output to
1663 CONFIG_VIDEO_CT69000
1665 Enable Chips & Technologies 69000 Video chip
1667 CONFIG_VIDEO_SMI_LYNXEM
1668 Enable Silicon Motion SMI 712/710/810 Video chip. The
1669 video output is selected via environment 'videoout'
1670 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1673 For the CT69000 and SMI_LYNXEM drivers, videomode is
1674 selected via environment 'videomode'. Two different ways
1676 - "videomode=num" 'num' is a standard LiLo mode numbers.
1677 Following standard modes are supported (* is default):
1679 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1680 -------------+---------------------------------------------
1681 8 bits | 0x301* 0x303 0x305 0x161 0x307
1682 15 bits | 0x310 0x313 0x316 0x162 0x319
1683 16 bits | 0x311 0x314 0x317 0x163 0x31A
1684 24 bits | 0x312 0x315 0x318 ? 0x31B
1685 -------------+---------------------------------------------
1686 (i.e. setenv videomode 317; saveenv; reset;)
1688 - "videomode=bootargs" all the video parameters are parsed
1689 from the bootargs. (See drivers/video/videomodes.c)
1692 CONFIG_VIDEO_SED13806
1693 Enable Epson SED13806 driver. This driver supports 8bpp
1694 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1695 or CONFIG_VIDEO_SED13806_16BPP
1698 Enable the Freescale DIU video driver. Reference boards for
1699 SOCs that have a DIU should define this macro to enable DIU
1700 support, and should also define these other macros:
1706 CONFIG_VIDEO_SW_CURSOR
1707 CONFIG_VGA_AS_SINGLE_DEVICE
1709 CONFIG_VIDEO_BMP_LOGO
1711 The DIU driver will look for the 'video-mode' environment
1712 variable, and if defined, enable the DIU as a console during
1713 boot. See the documentation file README.video for a
1714 description of this variable.
1718 Enable the VGA video / BIOS for x86. The alternative if you
1719 are using coreboot is to use the coreboot frame buffer
1726 Define this to enable a custom keyboard support.
1727 This simply calls drv_keyboard_init() which must be
1728 defined in your board-specific files.
1729 The only board using this so far is RBC823.
1731 - LCD Support: CONFIG_LCD
1733 Define this to enable LCD support (for output to LCD
1734 display); also select one of the supported displays
1735 by defining one of these:
1739 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1741 CONFIG_NEC_NL6448AC33:
1743 NEC NL6448AC33-18. Active, color, single scan.
1745 CONFIG_NEC_NL6448BC20
1747 NEC NL6448BC20-08. 6.5", 640x480.
1748 Active, color, single scan.
1750 CONFIG_NEC_NL6448BC33_54
1752 NEC NL6448BC33-54. 10.4", 640x480.
1753 Active, color, single scan.
1757 Sharp 320x240. Active, color, single scan.
1758 It isn't 16x9, and I am not sure what it is.
1760 CONFIG_SHARP_LQ64D341
1762 Sharp LQ64D341 display, 640x480.
1763 Active, color, single scan.
1767 HLD1045 display, 640x480.
1768 Active, color, single scan.
1772 Optrex CBL50840-2 NF-FW 99 22 M5
1774 Hitachi LMG6912RPFC-00T
1778 320x240. Black & white.
1780 Normally display is black on white background; define
1781 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1783 CONFIG_LCD_ALIGNMENT
1785 Normally the LCD is page-aligned (tyically 4KB). If this is
1786 defined then the LCD will be aligned to this value instead.
1787 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1788 here, since it is cheaper to change data cache settings on
1789 a per-section basis.
1791 CONFIG_CONSOLE_SCROLL_LINES
1793 When the console need to be scrolled, this is the number of
1794 lines to scroll by. It defaults to 1. Increasing this makes
1795 the console jump but can help speed up operation when scrolling
1800 Support drawing of RLE8-compressed bitmaps on the LCD.
1804 Enables an 'i2c edid' command which can read EDID
1805 information over I2C from an attached LCD display.
1807 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1809 If this option is set, the environment is checked for
1810 a variable "splashimage". If found, the usual display
1811 of logo, copyright and system information on the LCD
1812 is suppressed and the BMP image at the address
1813 specified in "splashimage" is loaded instead. The
1814 console is redirected to the "nulldev", too. This
1815 allows for a "silent" boot where a splash screen is
1816 loaded very quickly after power-on.
1818 CONFIG_SPLASHIMAGE_GUARD
1820 If this option is set, then U-Boot will prevent the environment
1821 variable "splashimage" from being set to a problematic address
1822 (see README.displaying-bmps).
1823 This option is useful for targets where, due to alignment
1824 restrictions, an improperly aligned BMP image will cause a data
1825 abort. If you think you will not have problems with unaligned
1826 accesses (for example because your toolchain prevents them)
1827 there is no need to set this option.
1829 CONFIG_SPLASH_SCREEN_ALIGN
1831 If this option is set the splash image can be freely positioned
1832 on the screen. Environment variable "splashpos" specifies the
1833 position as "x,y". If a positive number is given it is used as
1834 number of pixel from left/top. If a negative number is given it
1835 is used as number of pixel from right/bottom. You can also
1836 specify 'm' for centering the image.
1839 setenv splashpos m,m
1840 => image at center of screen
1842 setenv splashpos 30,20
1843 => image at x = 30 and y = 20
1845 setenv splashpos -10,m
1846 => vertically centered image
1847 at x = dspWidth - bmpWidth - 9
1849 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1851 If this option is set, additionally to standard BMP
1852 images, gzipped BMP images can be displayed via the
1853 splashscreen support or the bmp command.
1855 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1857 If this option is set, 8-bit RLE compressed BMP images
1858 can be displayed via the splashscreen support or the
1861 - Do compresssing for memory range:
1864 If this option is set, it would use zlib deflate method
1865 to compress the specified memory at its best effort.
1867 - Compression support:
1870 Enabled by default to support gzip compressed images.
1874 If this option is set, support for bzip2 compressed
1875 images is included. If not, only uncompressed and gzip
1876 compressed images are supported.
1878 NOTE: the bzip2 algorithm requires a lot of RAM, so
1879 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1884 If this option is set, support for lzma compressed
1887 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1888 requires an amount of dynamic memory that is given by the
1891 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1893 Where lc and lp stand for, respectively, Literal context bits
1894 and Literal pos bits.
1896 This value is upper-bounded by 14MB in the worst case. Anyway,
1897 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1898 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1899 a very small buffer.
1901 Use the lzmainfo tool to determinate the lc and lp values and
1902 then calculate the amount of needed dynamic memory (ensuring
1903 the appropriate CONFIG_SYS_MALLOC_LEN value).
1907 If this option is set, support for LZO compressed images
1913 The address of PHY on MII bus.
1915 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1917 The clock frequency of the MII bus
1921 If this option is set, support for speed/duplex
1922 detection of gigabit PHY is included.
1924 CONFIG_PHY_RESET_DELAY
1926 Some PHY like Intel LXT971A need extra delay after
1927 reset before any MII register access is possible.
1928 For such PHY, set this option to the usec delay
1929 required. (minimum 300usec for LXT971A)
1931 CONFIG_PHY_CMD_DELAY (ppc4xx)
1933 Some PHY like Intel LXT971A need extra delay after
1934 command issued before MII status register can be read
1944 Define a default value for Ethernet address to use
1945 for the respective Ethernet interface, in case this
1946 is not determined automatically.
1951 Define a default value for the IP address to use for
1952 the default Ethernet interface, in case this is not
1953 determined through e.g. bootp.
1954 (Environment variable "ipaddr")
1956 - Server IP address:
1959 Defines a default value for the IP address of a TFTP
1960 server to contact when using the "tftboot" command.
1961 (Environment variable "serverip")
1963 CONFIG_KEEP_SERVERADDR
1965 Keeps the server's MAC address, in the env 'serveraddr'
1966 for passing to bootargs (like Linux's netconsole option)
1968 - Gateway IP address:
1971 Defines a default value for the IP address of the
1972 default router where packets to other networks are
1974 (Environment variable "gatewayip")
1979 Defines a default value for the subnet mask (or
1980 routing prefix) which is used to determine if an IP
1981 address belongs to the local subnet or needs to be
1982 forwarded through a router.
1983 (Environment variable "netmask")
1985 - Multicast TFTP Mode:
1988 Defines whether you want to support multicast TFTP as per
1989 rfc-2090; for example to work with atftp. Lets lots of targets
1990 tftp down the same boot image concurrently. Note: the Ethernet
1991 driver in use must provide a function: mcast() to join/leave a
1994 - BOOTP Recovery Mode:
1995 CONFIG_BOOTP_RANDOM_DELAY
1997 If you have many targets in a network that try to
1998 boot using BOOTP, you may want to avoid that all
1999 systems send out BOOTP requests at precisely the same
2000 moment (which would happen for instance at recovery
2001 from a power failure, when all systems will try to
2002 boot, thus flooding the BOOTP server. Defining
2003 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2004 inserted before sending out BOOTP requests. The
2005 following delays are inserted then:
2007 1st BOOTP request: delay 0 ... 1 sec
2008 2nd BOOTP request: delay 0 ... 2 sec
2009 3rd BOOTP request: delay 0 ... 4 sec
2011 BOOTP requests: delay 0 ... 8 sec
2013 - DHCP Advanced Options:
2014 You can fine tune the DHCP functionality by defining
2015 CONFIG_BOOTP_* symbols:
2017 CONFIG_BOOTP_SUBNETMASK
2018 CONFIG_BOOTP_GATEWAY
2019 CONFIG_BOOTP_HOSTNAME
2020 CONFIG_BOOTP_NISDOMAIN
2021 CONFIG_BOOTP_BOOTPATH
2022 CONFIG_BOOTP_BOOTFILESIZE
2025 CONFIG_BOOTP_SEND_HOSTNAME
2026 CONFIG_BOOTP_NTPSERVER
2027 CONFIG_BOOTP_TIMEOFFSET
2028 CONFIG_BOOTP_VENDOREX
2029 CONFIG_BOOTP_MAY_FAIL
2031 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2032 environment variable, not the BOOTP server.
2034 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2035 after the configured retry count, the call will fail
2036 instead of starting over. This can be used to fail over
2037 to Link-local IP address configuration if the DHCP server
2040 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2041 serverip from a DHCP server, it is possible that more
2042 than one DNS serverip is offered to the client.
2043 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2044 serverip will be stored in the additional environment
2045 variable "dnsip2". The first DNS serverip is always
2046 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2049 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2050 to do a dynamic update of a DNS server. To do this, they
2051 need the hostname of the DHCP requester.
2052 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2053 of the "hostname" environment variable is passed as
2054 option 12 to the DHCP server.
2056 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2058 A 32bit value in microseconds for a delay between
2059 receiving a "DHCP Offer" and sending the "DHCP Request".
2060 This fixes a problem with certain DHCP servers that don't
2061 respond 100% of the time to a "DHCP request". E.g. On an
2062 AT91RM9200 processor running at 180MHz, this delay needed
2063 to be *at least* 15,000 usec before a Windows Server 2003
2064 DHCP server would reply 100% of the time. I recommend at
2065 least 50,000 usec to be safe. The alternative is to hope
2066 that one of the retries will be successful but note that
2067 the DHCP timeout and retry process takes a longer than
2070 - Link-local IP address negotiation:
2071 Negotiate with other link-local clients on the local network
2072 for an address that doesn't require explicit configuration.
2073 This is especially useful if a DHCP server cannot be guaranteed
2074 to exist in all environments that the device must operate.
2076 See doc/README.link-local for more information.
2079 CONFIG_CDP_DEVICE_ID
2081 The device id used in CDP trigger frames.
2083 CONFIG_CDP_DEVICE_ID_PREFIX
2085 A two character string which is prefixed to the MAC address
2090 A printf format string which contains the ascii name of
2091 the port. Normally is set to "eth%d" which sets
2092 eth0 for the first Ethernet, eth1 for the second etc.
2094 CONFIG_CDP_CAPABILITIES
2096 A 32bit integer which indicates the device capabilities;
2097 0x00000010 for a normal host which does not forwards.
2101 An ascii string containing the version of the software.
2105 An ascii string containing the name of the platform.
2109 A 32bit integer sent on the trigger.
2111 CONFIG_CDP_POWER_CONSUMPTION
2113 A 16bit integer containing the power consumption of the
2114 device in .1 of milliwatts.
2116 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2118 A byte containing the id of the VLAN.
2120 - Status LED: CONFIG_STATUS_LED
2122 Several configurations allow to display the current
2123 status using a LED. For instance, the LED will blink
2124 fast while running U-Boot code, stop blinking as
2125 soon as a reply to a BOOTP request was received, and
2126 start blinking slow once the Linux kernel is running
2127 (supported by a status LED driver in the Linux
2128 kernel). Defining CONFIG_STATUS_LED enables this
2134 The status LED can be connected to a GPIO pin.
2135 In such cases, the gpio_led driver can be used as a
2136 status LED backend implementation. Define CONFIG_GPIO_LED
2137 to include the gpio_led driver in the U-Boot binary.
2139 CONFIG_GPIO_LED_INVERTED_TABLE
2140 Some GPIO connected LEDs may have inverted polarity in which
2141 case the GPIO high value corresponds to LED off state and
2142 GPIO low value corresponds to LED on state.
2143 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2144 with a list of GPIO LEDs that have inverted polarity.
2146 - CAN Support: CONFIG_CAN_DRIVER
2148 Defining CONFIG_CAN_DRIVER enables CAN driver support
2149 on those systems that support this (optional)
2150 feature, like the TQM8xxL modules.
2152 - I2C Support: CONFIG_SYS_I2C
2154 This enable the NEW i2c subsystem, and will allow you to use
2155 i2c commands at the u-boot command line (as long as you set
2156 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2157 based realtime clock chips or other i2c devices. See
2158 common/cmd_i2c.c for a description of the command line
2161 ported i2c driver to the new framework:
2162 - drivers/i2c/soft_i2c.c:
2163 - activate first bus with CONFIG_SYS_I2C_SOFT define
2164 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2165 for defining speed and slave address
2166 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2167 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2168 for defining speed and slave address
2169 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2170 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2171 for defining speed and slave address
2172 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2173 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2174 for defining speed and slave address
2176 - drivers/i2c/fsl_i2c.c:
2177 - activate i2c driver with CONFIG_SYS_I2C_FSL
2178 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2179 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2180 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2182 - If your board supports a second fsl i2c bus, define
2183 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2184 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2185 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2188 - drivers/i2c/tegra_i2c.c:
2189 - activate this driver with CONFIG_SYS_I2C_TEGRA
2190 - This driver adds 4 i2c buses with a fix speed from
2191 100000 and the slave addr 0!
2193 - drivers/i2c/ppc4xx_i2c.c
2194 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2195 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2196 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2198 - drivers/i2c/i2c_mxc.c
2199 - activate this driver with CONFIG_SYS_I2C_MXC
2200 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2201 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2202 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2203 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2204 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2205 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2206 If thoses defines are not set, default value is 100000
2207 for speed, and 0 for slave.
2209 - drivers/i2c/rcar_i2c.c:
2210 - activate this driver with CONFIG_SYS_I2C_RCAR
2211 - This driver adds 4 i2c buses
2213 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2214 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2215 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2216 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2217 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2218 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2219 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2220 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2221 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2223 - drivers/i2c/sh_i2c.c:
2224 - activate this driver with CONFIG_SYS_I2C_SH
2225 - This driver adds from 2 to 5 i2c buses
2227 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2228 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2229 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2230 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2231 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2232 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2233 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2234 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2235 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2236 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2237 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2238 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2239 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2241 - drivers/i2c/omap24xx_i2c.c
2242 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2243 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2244 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2245 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2246 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2247 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2248 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2249 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2250 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2251 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2252 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2254 - drivers/i2c/zynq_i2c.c
2255 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2256 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2257 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2259 - drivers/i2c/s3c24x0_i2c.c:
2260 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2261 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2262 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2263 with a fix speed from 100000 and the slave addr 0!
2267 CONFIG_SYS_NUM_I2C_BUSES
2268 Hold the number of i2c busses you want to use. If you
2269 don't use/have i2c muxes on your i2c bus, this
2270 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2273 CONFIG_SYS_I2C_DIRECT_BUS
2274 define this, if you don't use i2c muxes on your hardware.
2275 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2278 CONFIG_SYS_I2C_MAX_HOPS
2279 define how many muxes are maximal consecutively connected
2280 on one i2c bus. If you not use i2c muxes, omit this
2283 CONFIG_SYS_I2C_BUSES
2284 hold a list of busses you want to use, only used if
2285 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2286 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2287 CONFIG_SYS_NUM_I2C_BUSES = 9:
2289 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2290 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2291 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2292 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2293 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2294 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2295 {1, {I2C_NULL_HOP}}, \
2296 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2297 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2301 bus 0 on adapter 0 without a mux
2302 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2303 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2304 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2305 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2306 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2307 bus 6 on adapter 1 without a mux
2308 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2309 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2311 If you do not have i2c muxes on your board, omit this define.
2313 - Legacy I2C Support: CONFIG_HARD_I2C
2315 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2316 provides the following compelling advantages:
2318 - more than one i2c adapter is usable
2319 - approved multibus support
2320 - better i2c mux support
2322 ** Please consider updating your I2C driver now. **
2324 These enable legacy I2C serial bus commands. Defining
2325 CONFIG_HARD_I2C will include the appropriate I2C driver
2326 for the selected CPU.
2328 This will allow you to use i2c commands at the u-boot
2329 command line (as long as you set CONFIG_CMD_I2C in
2330 CONFIG_COMMANDS) and communicate with i2c based realtime
2331 clock chips. See common/cmd_i2c.c for a description of the
2332 command line interface.
2334 CONFIG_HARD_I2C selects a hardware I2C controller.
2336 There are several other quantities that must also be
2337 defined when you define CONFIG_HARD_I2C.
2339 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2340 to be the frequency (in Hz) at which you wish your i2c bus
2341 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2342 the CPU's i2c node address).
2344 Now, the u-boot i2c code for the mpc8xx
2345 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2346 and so its address should therefore be cleared to 0 (See,
2347 eg, MPC823e User's Manual p.16-473). So, set
2348 CONFIG_SYS_I2C_SLAVE to 0.
2350 CONFIG_SYS_I2C_INIT_MPC5XXX
2352 When a board is reset during an i2c bus transfer
2353 chips might think that the current transfer is still
2354 in progress. Reset the slave devices by sending start
2355 commands until the slave device responds.
2357 That's all that's required for CONFIG_HARD_I2C.
2359 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2360 then the following macros need to be defined (examples are
2361 from include/configs/lwmon.h):
2365 (Optional). Any commands necessary to enable the I2C
2366 controller or configure ports.
2368 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2372 (Only for MPC8260 CPU). The I/O port to use (the code
2373 assumes both bits are on the same port). Valid values
2374 are 0..3 for ports A..D.
2378 The code necessary to make the I2C data line active
2379 (driven). If the data line is open collector, this
2382 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2386 The code necessary to make the I2C data line tri-stated
2387 (inactive). If the data line is open collector, this
2390 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2394 Code that returns true if the I2C data line is high,
2397 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2401 If <bit> is true, sets the I2C data line high. If it
2402 is false, it clears it (low).
2404 eg: #define I2C_SDA(bit) \
2405 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2406 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2410 If <bit> is true, sets the I2C clock line high. If it
2411 is false, it clears it (low).
2413 eg: #define I2C_SCL(bit) \
2414 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2415 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2419 This delay is invoked four times per clock cycle so this
2420 controls the rate of data transfer. The data rate thus
2421 is 1 / (I2C_DELAY * 4). Often defined to be something
2424 #define I2C_DELAY udelay(2)
2426 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2428 If your arch supports the generic GPIO framework (asm/gpio.h),
2429 then you may alternatively define the two GPIOs that are to be
2430 used as SCL / SDA. Any of the previous I2C_xxx macros will
2431 have GPIO-based defaults assigned to them as appropriate.
2433 You should define these to the GPIO value as given directly to
2434 the generic GPIO functions.
2436 CONFIG_SYS_I2C_INIT_BOARD
2438 When a board is reset during an i2c bus transfer
2439 chips might think that the current transfer is still
2440 in progress. On some boards it is possible to access
2441 the i2c SCLK line directly, either by using the
2442 processor pin as a GPIO or by having a second pin
2443 connected to the bus. If this option is defined a
2444 custom i2c_init_board() routine in boards/xxx/board.c
2445 is run early in the boot sequence.
2447 CONFIG_SYS_I2C_BOARD_LATE_INIT
2449 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2450 defined a custom i2c_board_late_init() routine in
2451 boards/xxx/board.c is run AFTER the operations in i2c_init()
2452 is completed. This callpoint can be used to unreset i2c bus
2453 using CPU i2c controller register accesses for CPUs whose i2c
2454 controller provide such a method. It is called at the end of
2455 i2c_init() to allow i2c_init operations to setup the i2c bus
2456 controller on the CPU (e.g. setting bus speed & slave address).
2458 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2460 This option enables configuration of bi_iic_fast[] flags
2461 in u-boot bd_info structure based on u-boot environment
2462 variable "i2cfast". (see also i2cfast)
2464 CONFIG_I2C_MULTI_BUS
2466 This option allows the use of multiple I2C buses, each of which
2467 must have a controller. At any point in time, only one bus is
2468 active. To switch to a different bus, use the 'i2c dev' command.
2469 Note that bus numbering is zero-based.
2471 CONFIG_SYS_I2C_NOPROBES
2473 This option specifies a list of I2C devices that will be skipped
2474 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2475 is set, specify a list of bus-device pairs. Otherwise, specify
2476 a 1D array of device addresses
2479 #undef CONFIG_I2C_MULTI_BUS
2480 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2482 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2484 #define CONFIG_I2C_MULTI_BUS
2485 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2487 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2489 CONFIG_SYS_SPD_BUS_NUM
2491 If defined, then this indicates the I2C bus number for DDR SPD.
2492 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2494 CONFIG_SYS_RTC_BUS_NUM
2496 If defined, then this indicates the I2C bus number for the RTC.
2497 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2499 CONFIG_SYS_DTT_BUS_NUM
2501 If defined, then this indicates the I2C bus number for the DTT.
2502 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2504 CONFIG_SYS_I2C_DTT_ADDR:
2506 If defined, specifies the I2C address of the DTT device.
2507 If not defined, then U-Boot uses predefined value for
2508 specified DTT device.
2510 CONFIG_SOFT_I2C_READ_REPEATED_START
2512 defining this will force the i2c_read() function in
2513 the soft_i2c driver to perform an I2C repeated start
2514 between writing the address pointer and reading the
2515 data. If this define is omitted the default behaviour
2516 of doing a stop-start sequence will be used. Most I2C
2517 devices can use either method, but some require one or
2520 - SPI Support: CONFIG_SPI
2522 Enables SPI driver (so far only tested with
2523 SPI EEPROM, also an instance works with Crystal A/D and
2524 D/As on the SACSng board)
2528 Enables the driver for SPI controller on SuperH. Currently
2529 only SH7757 is supported.
2533 Enables extended (16-bit) SPI EEPROM addressing.
2534 (symmetrical to CONFIG_I2C_X)
2538 Enables a software (bit-bang) SPI driver rather than
2539 using hardware support. This is a general purpose
2540 driver that only requires three general I/O port pins
2541 (two outputs, one input) to function. If this is
2542 defined, the board configuration must define several
2543 SPI configuration items (port pins to use, etc). For
2544 an example, see include/configs/sacsng.h.
2548 Enables a hardware SPI driver for general-purpose reads
2549 and writes. As with CONFIG_SOFT_SPI, the board configuration
2550 must define a list of chip-select function pointers.
2551 Currently supported on some MPC8xxx processors. For an
2552 example, see include/configs/mpc8349emds.h.
2556 Enables the driver for the SPI controllers on i.MX and MXC
2557 SoCs. Currently i.MX31/35/51 are supported.
2559 - FPGA Support: CONFIG_FPGA
2561 Enables FPGA subsystem.
2563 CONFIG_FPGA_<vendor>
2565 Enables support for specific chip vendors.
2568 CONFIG_FPGA_<family>
2570 Enables support for FPGA family.
2571 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2575 Specify the number of FPGA devices to support.
2577 CONFIG_CMD_FPGA_LOADMK
2579 Enable support for fpga loadmk command
2581 CONFIG_CMD_FPGA_LOADP
2583 Enable support for fpga loadp command - load partial bitstream
2585 CONFIG_CMD_FPGA_LOADBP
2587 Enable support for fpga loadbp command - load partial bitstream
2590 CONFIG_SYS_FPGA_PROG_FEEDBACK
2592 Enable printing of hash marks during FPGA configuration.
2594 CONFIG_SYS_FPGA_CHECK_BUSY
2596 Enable checks on FPGA configuration interface busy
2597 status by the configuration function. This option
2598 will require a board or device specific function to
2603 If defined, a function that provides delays in the FPGA
2604 configuration driver.
2606 CONFIG_SYS_FPGA_CHECK_CTRLC
2607 Allow Control-C to interrupt FPGA configuration
2609 CONFIG_SYS_FPGA_CHECK_ERROR
2611 Check for configuration errors during FPGA bitfile
2612 loading. For example, abort during Virtex II
2613 configuration if the INIT_B line goes low (which
2614 indicated a CRC error).
2616 CONFIG_SYS_FPGA_WAIT_INIT
2618 Maximum time to wait for the INIT_B line to deassert
2619 after PROB_B has been deasserted during a Virtex II
2620 FPGA configuration sequence. The default time is 500
2623 CONFIG_SYS_FPGA_WAIT_BUSY
2625 Maximum time to wait for BUSY to deassert during
2626 Virtex II FPGA configuration. The default is 5 ms.
2628 CONFIG_SYS_FPGA_WAIT_CONFIG
2630 Time to wait after FPGA configuration. The default is
2633 - Configuration Management:
2636 If defined, this string will be added to the U-Boot
2637 version information (U_BOOT_VERSION)
2639 - Vendor Parameter Protection:
2641 U-Boot considers the values of the environment
2642 variables "serial#" (Board Serial Number) and
2643 "ethaddr" (Ethernet Address) to be parameters that
2644 are set once by the board vendor / manufacturer, and
2645 protects these variables from casual modification by
2646 the user. Once set, these variables are read-only,
2647 and write or delete attempts are rejected. You can
2648 change this behaviour:
2650 If CONFIG_ENV_OVERWRITE is #defined in your config
2651 file, the write protection for vendor parameters is
2652 completely disabled. Anybody can change or delete
2655 Alternatively, if you #define _both_ CONFIG_ETHADDR
2656 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2657 Ethernet address is installed in the environment,
2658 which can be changed exactly ONCE by the user. [The
2659 serial# is unaffected by this, i. e. it remains
2662 The same can be accomplished in a more flexible way
2663 for any variable by configuring the type of access
2664 to allow for those variables in the ".flags" variable
2665 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2670 Define this variable to enable the reservation of
2671 "protected RAM", i. e. RAM which is not overwritten
2672 by U-Boot. Define CONFIG_PRAM to hold the number of
2673 kB you want to reserve for pRAM. You can overwrite
2674 this default value by defining an environment
2675 variable "pram" to the number of kB you want to
2676 reserve. Note that the board info structure will
2677 still show the full amount of RAM. If pRAM is
2678 reserved, a new environment variable "mem" will
2679 automatically be defined to hold the amount of
2680 remaining RAM in a form that can be passed as boot
2681 argument to Linux, for instance like that:
2683 setenv bootargs ... mem=\${mem}
2686 This way you can tell Linux not to use this memory,
2687 either, which results in a memory region that will
2688 not be affected by reboots.
2690 *WARNING* If your board configuration uses automatic
2691 detection of the RAM size, you must make sure that
2692 this memory test is non-destructive. So far, the
2693 following board configurations are known to be
2696 IVMS8, IVML24, SPD8xx, TQM8xxL,
2697 HERMES, IP860, RPXlite, LWMON,
2700 - Access to physical memory region (> 4GB)
2701 Some basic support is provided for operations on memory not
2702 normally accessible to U-Boot - e.g. some architectures
2703 support access to more than 4GB of memory on 32-bit
2704 machines using physical address extension or similar.
2705 Define CONFIG_PHYSMEM to access this basic support, which
2706 currently only supports clearing the memory.
2711 Define this variable to stop the system in case of a
2712 fatal error, so that you have to reset it manually.
2713 This is probably NOT a good idea for an embedded
2714 system where you want the system to reboot
2715 automatically as fast as possible, but it may be
2716 useful during development since you can try to debug
2717 the conditions that lead to the situation.
2719 CONFIG_NET_RETRY_COUNT
2721 This variable defines the number of retries for
2722 network operations like ARP, RARP, TFTP, or BOOTP
2723 before giving up the operation. If not defined, a
2724 default value of 5 is used.
2728 Timeout waiting for an ARP reply in milliseconds.
2732 Timeout in milliseconds used in NFS protocol.
2733 If you encounter "ERROR: Cannot umount" in nfs command,
2734 try longer timeout such as
2735 #define CONFIG_NFS_TIMEOUT 10000UL
2737 - Command Interpreter:
2738 CONFIG_AUTO_COMPLETE
2740 Enable auto completion of commands using TAB.
2742 Note that this feature has NOT been implemented yet
2743 for the "hush" shell.
2746 CONFIG_SYS_HUSH_PARSER
2748 Define this variable to enable the "hush" shell (from
2749 Busybox) as command line interpreter, thus enabling
2750 powerful command line syntax like
2751 if...then...else...fi conditionals or `&&' and '||'
2752 constructs ("shell scripts").
2754 If undefined, you get the old, much simpler behaviour
2755 with a somewhat smaller memory footprint.
2758 CONFIG_SYS_PROMPT_HUSH_PS2
2760 This defines the secondary prompt string, which is
2761 printed when the command interpreter needs more input
2762 to complete a command. Usually "> ".
2766 In the current implementation, the local variables
2767 space and global environment variables space are
2768 separated. Local variables are those you define by
2769 simply typing `name=value'. To access a local
2770 variable later on, you have write `$name' or
2771 `${name}'; to execute the contents of a variable
2772 directly type `$name' at the command prompt.
2774 Global environment variables are those you use
2775 setenv/printenv to work with. To run a command stored
2776 in such a variable, you need to use the run command,
2777 and you must not use the '$' sign to access them.
2779 To store commands and special characters in a
2780 variable, please use double quotation marks
2781 surrounding the whole text of the variable, instead
2782 of the backslashes before semicolons and special
2785 - Commandline Editing and History:
2786 CONFIG_CMDLINE_EDITING
2788 Enable editing and History functions for interactive
2789 commandline input operations
2791 - Default Environment:
2792 CONFIG_EXTRA_ENV_SETTINGS
2794 Define this to contain any number of null terminated
2795 strings (variable = value pairs) that will be part of
2796 the default environment compiled into the boot image.
2798 For example, place something like this in your
2799 board's config file:
2801 #define CONFIG_EXTRA_ENV_SETTINGS \
2805 Warning: This method is based on knowledge about the
2806 internal format how the environment is stored by the
2807 U-Boot code. This is NOT an official, exported
2808 interface! Although it is unlikely that this format
2809 will change soon, there is no guarantee either.
2810 You better know what you are doing here.
2812 Note: overly (ab)use of the default environment is
2813 discouraged. Make sure to check other ways to preset
2814 the environment like the "source" command or the
2817 CONFIG_ENV_VARS_UBOOT_CONFIG
2819 Define this in order to add variables describing the
2820 U-Boot build configuration to the default environment.
2821 These will be named arch, cpu, board, vendor, and soc.
2823 Enabling this option will cause the following to be defined:
2831 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2833 Define this in order to add variables describing certain
2834 run-time determined information about the hardware to the
2835 environment. These will be named board_name, board_rev.
2837 CONFIG_DELAY_ENVIRONMENT
2839 Normally the environment is loaded when the board is
2840 intialised so that it is available to U-Boot. This inhibits
2841 that so that the environment is not available until
2842 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2843 this is instead controlled by the value of
2844 /config/load-environment.
2846 - DataFlash Support:
2847 CONFIG_HAS_DATAFLASH
2849 Defining this option enables DataFlash features and
2850 allows to read/write in Dataflash via the standard
2853 - Serial Flash support
2856 Defining this option enables SPI flash commands
2857 'sf probe/read/write/erase/update'.
2859 Usage requires an initial 'probe' to define the serial
2860 flash parameters, followed by read/write/erase/update
2863 The following defaults may be provided by the platform
2864 to handle the common case when only a single serial
2865 flash is present on the system.
2867 CONFIG_SF_DEFAULT_BUS Bus identifier
2868 CONFIG_SF_DEFAULT_CS Chip-select
2869 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2870 CONFIG_SF_DEFAULT_SPEED in Hz
2874 Define this option to include a destructive SPI flash
2877 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2879 Define this option to use the Bank addr/Extended addr
2880 support on SPI flashes which has size > 16Mbytes.
2882 CONFIG_SF_DUAL_FLASH Dual flash memories
2884 Define this option to use dual flash support where two flash
2885 memories can be connected with a given cs line.
2886 currently Xilinx Zynq qspi support these type of connections.
2888 - SystemACE Support:
2891 Adding this option adds support for Xilinx SystemACE
2892 chips attached via some sort of local bus. The address
2893 of the chip must also be defined in the
2894 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2896 #define CONFIG_SYSTEMACE
2897 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2899 When SystemACE support is added, the "ace" device type
2900 becomes available to the fat commands, i.e. fatls.
2902 - TFTP Fixed UDP Port:
2905 If this is defined, the environment variable tftpsrcp
2906 is used to supply the TFTP UDP source port value.
2907 If tftpsrcp isn't defined, the normal pseudo-random port
2908 number generator is used.
2910 Also, the environment variable tftpdstp is used to supply
2911 the TFTP UDP destination port value. If tftpdstp isn't
2912 defined, the normal port 69 is used.
2914 The purpose for tftpsrcp is to allow a TFTP server to
2915 blindly start the TFTP transfer using the pre-configured
2916 target IP address and UDP port. This has the effect of
2917 "punching through" the (Windows XP) firewall, allowing
2918 the remainder of the TFTP transfer to proceed normally.
2919 A better solution is to properly configure the firewall,
2920 but sometimes that is not allowed.
2925 This enables a generic 'hash' command which can produce
2926 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2930 Enable the hash verify command (hash -v). This adds to code
2933 CONFIG_SHA1 - support SHA1 hashing
2934 CONFIG_SHA256 - support SHA256 hashing
2936 Note: There is also a sha1sum command, which should perhaps
2937 be deprecated in favour of 'hash sha1'.
2939 - Freescale i.MX specific commands:
2940 CONFIG_CMD_HDMIDETECT
2941 This enables 'hdmidet' command which returns true if an
2942 HDMI monitor is detected. This command is i.MX 6 specific.
2945 This enables the 'bmode' (bootmode) command for forcing
2946 a boot from specific media.
2948 This is useful for forcing the ROM's usb downloader to
2949 activate upon a watchdog reset which is nice when iterating
2950 on U-Boot. Using the reset button or running bmode normal
2951 will set it back to normal. This command currently
2952 supports i.MX53 and i.MX6.
2957 This enables the RSA algorithm used for FIT image verification
2958 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2960 The signing part is build into mkimage regardless of this
2963 - bootcount support:
2964 CONFIG_BOOTCOUNT_LIMIT
2966 This enables the bootcounter support, see:
2967 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2970 enable special bootcounter support on at91sam9xe based boards.
2972 enable special bootcounter support on blackfin based boards.
2974 enable special bootcounter support on da850 based boards.
2975 CONFIG_BOOTCOUNT_RAM
2976 enable support for the bootcounter in RAM
2977 CONFIG_BOOTCOUNT_I2C
2978 enable support for the bootcounter on an i2c (like RTC) device.
2979 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2980 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2982 CONFIG_BOOTCOUNT_ALEN = address len
2984 - Show boot progress:
2985 CONFIG_SHOW_BOOT_PROGRESS
2987 Defining this option allows to add some board-
2988 specific code (calling a user-provided function
2989 "show_boot_progress(int)") that enables you to show
2990 the system's boot progress on some display (for
2991 example, some LED's) on your board. At the moment,
2992 the following checkpoints are implemented:
2994 - Detailed boot stage timing
2996 Define this option to get detailed timing of each stage
2997 of the boot process.
2999 CONFIG_BOOTSTAGE_USER_COUNT
3000 This is the number of available user bootstage records.
3001 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3002 a new ID will be allocated from this stash. If you exceed
3003 the limit, recording will stop.
3005 CONFIG_BOOTSTAGE_REPORT
3006 Define this to print a report before boot, similar to this:
3008 Timer summary in microseconds:
3011 3,575,678 3,575,678 board_init_f start
3012 3,575,695 17 arch_cpu_init A9
3013 3,575,777 82 arch_cpu_init done
3014 3,659,598 83,821 board_init_r start
3015 3,910,375 250,777 main_loop
3016 29,916,167 26,005,792 bootm_start
3017 30,361,327 445,160 start_kernel
3019 CONFIG_CMD_BOOTSTAGE
3020 Add a 'bootstage' command which supports printing a report
3021 and un/stashing of bootstage data.
3023 CONFIG_BOOTSTAGE_FDT
3024 Stash the bootstage information in the FDT. A root 'bootstage'
3025 node is created with each bootstage id as a child. Each child
3026 has a 'name' property and either 'mark' containing the
3027 mark time in microsecond, or 'accum' containing the
3028 accumulated time for that bootstage id in microseconds.
3033 name = "board_init_f";
3042 Code in the Linux kernel can find this in /proc/devicetree.
3044 Legacy uImage format:
3047 1 common/cmd_bootm.c before attempting to boot an image
3048 -1 common/cmd_bootm.c Image header has bad magic number
3049 2 common/cmd_bootm.c Image header has correct magic number
3050 -2 common/cmd_bootm.c Image header has bad checksum
3051 3 common/cmd_bootm.c Image header has correct checksum
3052 -3 common/cmd_bootm.c Image data has bad checksum
3053 4 common/cmd_bootm.c Image data has correct checksum
3054 -4 common/cmd_bootm.c Image is for unsupported architecture
3055 5 common/cmd_bootm.c Architecture check OK
3056 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3057 6 common/cmd_bootm.c Image Type check OK
3058 -6 common/cmd_bootm.c gunzip uncompression error
3059 -7 common/cmd_bootm.c Unimplemented compression type
3060 7 common/cmd_bootm.c Uncompression OK
3061 8 common/cmd_bootm.c No uncompress/copy overwrite error
3062 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3064 9 common/image.c Start initial ramdisk verification
3065 -10 common/image.c Ramdisk header has bad magic number
3066 -11 common/image.c Ramdisk header has bad checksum
3067 10 common/image.c Ramdisk header is OK
3068 -12 common/image.c Ramdisk data has bad checksum
3069 11 common/image.c Ramdisk data has correct checksum
3070 12 common/image.c Ramdisk verification complete, start loading
3071 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3072 13 common/image.c Start multifile image verification
3073 14 common/image.c No initial ramdisk, no multifile, continue.
3075 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3077 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3078 -31 post/post.c POST test failed, detected by post_output_backlog()
3079 -32 post/post.c POST test failed, detected by post_run_single()
3081 34 common/cmd_doc.c before loading a Image from a DOC device
3082 -35 common/cmd_doc.c Bad usage of "doc" command
3083 35 common/cmd_doc.c correct usage of "doc" command
3084 -36 common/cmd_doc.c No boot device
3085 36 common/cmd_doc.c correct boot device
3086 -37 common/cmd_doc.c Unknown Chip ID on boot device
3087 37 common/cmd_doc.c correct chip ID found, device available
3088 -38 common/cmd_doc.c Read Error on boot device
3089 38 common/cmd_doc.c reading Image header from DOC device OK
3090 -39 common/cmd_doc.c Image header has bad magic number
3091 39 common/cmd_doc.c Image header has correct magic number
3092 -40 common/cmd_doc.c Error reading Image from DOC device
3093 40 common/cmd_doc.c Image header has correct magic number
3094 41 common/cmd_ide.c before loading a Image from a IDE device
3095 -42 common/cmd_ide.c Bad usage of "ide" command
3096 42 common/cmd_ide.c correct usage of "ide" command
3097 -43 common/cmd_ide.c No boot device
3098 43 common/cmd_ide.c boot device found
3099 -44 common/cmd_ide.c Device not available
3100 44 common/cmd_ide.c Device available
3101 -45 common/cmd_ide.c wrong partition selected
3102 45 common/cmd_ide.c partition selected
3103 -46 common/cmd_ide.c Unknown partition table
3104 46 common/cmd_ide.c valid partition table found
3105 -47 common/cmd_ide.c Invalid partition type
3106 47 common/cmd_ide.c correct partition type
3107 -48 common/cmd_ide.c Error reading Image Header on boot device
3108 48 common/cmd_ide.c reading Image Header from IDE device OK
3109 -49 common/cmd_ide.c Image header has bad magic number
3110 49 common/cmd_ide.c Image header has correct magic number
3111 -50 common/cmd_ide.c Image header has bad checksum
3112 50 common/cmd_ide.c Image header has correct checksum
3113 -51 common/cmd_ide.c Error reading Image from IDE device
3114 51 common/cmd_ide.c reading Image from IDE device OK
3115 52 common/cmd_nand.c before loading a Image from a NAND device
3116 -53 common/cmd_nand.c Bad usage of "nand" command
3117 53 common/cmd_nand.c correct usage of "nand" command
3118 -54 common/cmd_nand.c No boot device
3119 54 common/cmd_nand.c boot device found
3120 -55 common/cmd_nand.c Unknown Chip ID on boot device
3121 55 common/cmd_nand.c correct chip ID found, device available
3122 -56 common/cmd_nand.c Error reading Image Header on boot device
3123 56 common/cmd_nand.c reading Image Header from NAND device OK
3124 -57 common/cmd_nand.c Image header has bad magic number
3125 57 common/cmd_nand.c Image header has correct magic number
3126 -58 common/cmd_nand.c Error reading Image from NAND device
3127 58 common/cmd_nand.c reading Image from NAND device OK
3129 -60 common/env_common.c Environment has a bad CRC, using default
3131 64 net/eth.c starting with Ethernet configuration.
3132 -64 net/eth.c no Ethernet found.
3133 65 net/eth.c Ethernet found.
3135 -80 common/cmd_net.c usage wrong
3136 80 common/cmd_net.c before calling NetLoop()
3137 -81 common/cmd_net.c some error in NetLoop() occurred
3138 81 common/cmd_net.c NetLoop() back without error
3139 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3140 82 common/cmd_net.c trying automatic boot
3141 83 common/cmd_net.c running "source" command
3142 -83 common/cmd_net.c some error in automatic boot or "source" command
3143 84 common/cmd_net.c end without errors
3148 100 common/cmd_bootm.c Kernel FIT Image has correct format
3149 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3150 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3151 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3152 102 common/cmd_bootm.c Kernel unit name specified
3153 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3154 103 common/cmd_bootm.c Found configuration node
3155 104 common/cmd_bootm.c Got kernel subimage node offset
3156 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3157 105 common/cmd_bootm.c Kernel subimage hash verification OK
3158 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3159 106 common/cmd_bootm.c Architecture check OK
3160 -106 common/cmd_bootm.c Kernel subimage has wrong type
3161 107 common/cmd_bootm.c Kernel subimage type OK
3162 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3163 108 common/cmd_bootm.c Got kernel subimage data/size
3164 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3165 -109 common/cmd_bootm.c Can't get kernel subimage type
3166 -110 common/cmd_bootm.c Can't get kernel subimage comp
3167 -111 common/cmd_bootm.c Can't get kernel subimage os
3168 -112 common/cmd_bootm.c Can't get kernel subimage load address
3169 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3171 120 common/image.c Start initial ramdisk verification
3172 -120 common/image.c Ramdisk FIT image has incorrect format
3173 121 common/image.c Ramdisk FIT image has correct format
3174 122 common/image.c No ramdisk subimage unit name, using configuration
3175 -122 common/image.c Can't get configuration for ramdisk subimage
3176 123 common/image.c Ramdisk unit name specified
3177 -124 common/image.c Can't get ramdisk subimage node offset
3178 125 common/image.c Got ramdisk subimage node offset
3179 -125 common/image.c Ramdisk subimage hash verification failed
3180 126 common/image.c Ramdisk subimage hash verification OK
3181 -126 common/image.c Ramdisk subimage for unsupported architecture
3182 127 common/image.c Architecture check OK
3183 -127 common/image.c Can't get ramdisk subimage data/size
3184 128 common/image.c Got ramdisk subimage data/size
3185 129 common/image.c Can't get ramdisk load address
3186 -129 common/image.c Got ramdisk load address
3188 -130 common/cmd_doc.c Incorrect FIT image format
3189 131 common/cmd_doc.c FIT image format OK
3191 -140 common/cmd_ide.c Incorrect FIT image format
3192 141 common/cmd_ide.c FIT image format OK
3194 -150 common/cmd_nand.c Incorrect FIT image format
3195 151 common/cmd_nand.c FIT image format OK
3197 - FIT image support:
3199 Enable support for the FIT uImage format.
3201 CONFIG_FIT_BEST_MATCH
3202 When no configuration is explicitly selected, default to the
3203 one whose fdt's compatibility field best matches that of
3204 U-Boot itself. A match is considered "best" if it matches the
3205 most specific compatibility entry of U-Boot's fdt's root node.
3206 The order of entries in the configuration's fdt is ignored.
3208 CONFIG_FIT_SIGNATURE
3209 This option enables signature verification of FIT uImages,
3210 using a hash signed and verified using RSA. See
3211 doc/uImage.FIT/signature.txt for more details.
3213 - Standalone program support:
3214 CONFIG_STANDALONE_LOAD_ADDR
3216 This option defines a board specific value for the
3217 address where standalone program gets loaded, thus
3218 overwriting the architecture dependent default
3221 - Frame Buffer Address:
3224 Define CONFIG_FB_ADDR if you want to use specific
3225 address for frame buffer. This is typically the case
3226 when using a graphics controller has separate video
3227 memory. U-Boot will then place the frame buffer at
3228 the given address instead of dynamically reserving it
3229 in system RAM by calling lcd_setmem(), which grabs
3230 the memory for the frame buffer depending on the
3231 configured panel size.
3233 Please see board_init_f function.
3235 - Automatic software updates via TFTP server
3237 CONFIG_UPDATE_TFTP_CNT_MAX
3238 CONFIG_UPDATE_TFTP_MSEC_MAX
3240 These options enable and control the auto-update feature;
3241 for a more detailed description refer to doc/README.update.
3243 - MTD Support (mtdparts command, UBI support)
3246 Adds the MTD device infrastructure from the Linux kernel.
3247 Needed for mtdparts command support.
3249 CONFIG_MTD_PARTITIONS
3251 Adds the MTD partitioning infrastructure from the Linux
3252 kernel. Needed for UBI support.
3257 Adds commands for interacting with MTD partitions formatted
3258 with the UBI flash translation layer
3260 Requires also defining CONFIG_RBTREE
3262 CONFIG_UBI_SILENCE_MSG
3264 Make the verbose messages from UBI stop printing. This leaves
3265 warnings and errors enabled.
3270 Adds commands for interacting with UBI volumes formatted as
3271 UBIFS. UBIFS is read-only in u-boot.
3273 Requires UBI support as well as CONFIG_LZO
3275 CONFIG_UBIFS_SILENCE_MSG
3277 Make the verbose messages from UBIFS stop printing. This leaves
3278 warnings and errors enabled.
3282 Enable building of SPL globally.
3285 LDSCRIPT for linking the SPL binary.
3287 CONFIG_SPL_MAX_FOOTPRINT
3288 Maximum size in memory allocated to the SPL, BSS included.
3289 When defined, the linker checks that the actual memory
3290 used by SPL from _start to __bss_end does not exceed it.
3291 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3292 must not be both defined at the same time.
3295 Maximum size of the SPL image (text, data, rodata, and
3296 linker lists sections), BSS excluded.
3297 When defined, the linker checks that the actual size does
3300 CONFIG_SPL_TEXT_BASE
3301 TEXT_BASE for linking the SPL binary.
3303 CONFIG_SPL_RELOC_TEXT_BASE
3304 Address to relocate to. If unspecified, this is equal to
3305 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3307 CONFIG_SPL_BSS_START_ADDR
3308 Link address for the BSS within the SPL binary.
3310 CONFIG_SPL_BSS_MAX_SIZE
3311 Maximum size in memory allocated to the SPL BSS.
3312 When defined, the linker checks that the actual memory used
3313 by SPL from __bss_start to __bss_end does not exceed it.
3314 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3315 must not be both defined at the same time.
3318 Adress of the start of the stack SPL will use
3320 CONFIG_SPL_RELOC_STACK
3321 Adress of the start of the stack SPL will use after
3322 relocation. If unspecified, this is equal to
3325 CONFIG_SYS_SPL_MALLOC_START
3326 Starting address of the malloc pool used in SPL.
3328 CONFIG_SYS_SPL_MALLOC_SIZE
3329 The size of the malloc pool used in SPL.
3331 CONFIG_SPL_FRAMEWORK
3332 Enable the SPL framework under common/. This framework
3333 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3334 NAND loading of the Linux Kernel.
3337 Enable booting directly to an OS from SPL.
3338 See also: doc/README.falcon
3340 CONFIG_SPL_DISPLAY_PRINT
3341 For ARM, enable an optional function to print more information
3342 about the running system.
3344 CONFIG_SPL_INIT_MINIMAL
3345 Arch init code should be built for a very small image
3347 CONFIG_SPL_LIBCOMMON_SUPPORT
3348 Support for common/libcommon.o in SPL binary
3350 CONFIG_SPL_LIBDISK_SUPPORT
3351 Support for disk/libdisk.o in SPL binary
3353 CONFIG_SPL_I2C_SUPPORT
3354 Support for drivers/i2c/libi2c.o in SPL binary
3356 CONFIG_SPL_GPIO_SUPPORT
3357 Support for drivers/gpio/libgpio.o in SPL binary
3359 CONFIG_SPL_MMC_SUPPORT
3360 Support for drivers/mmc/libmmc.o in SPL binary
3362 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3363 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3364 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3365 Address, size and partition on the MMC to load U-Boot from
3366 when the MMC is being used in raw mode.
3368 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3369 Sector to load kernel uImage from when MMC is being
3370 used in raw mode (for Falcon mode)
3372 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3373 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3374 Sector and number of sectors to load kernel argument
3375 parameters from when MMC is being used in raw mode
3378 CONFIG_SPL_FAT_SUPPORT
3379 Support for fs/fat/libfat.o in SPL binary
3381 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3382 Filename to read to load U-Boot when reading from FAT
3384 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3385 Filename to read to load kernel uImage when reading
3386 from FAT (for Falcon mode)
3388 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3389 Filename to read to load kernel argument parameters
3390 when reading from FAT (for Falcon mode)
3392 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3393 Set this for NAND SPL on PPC mpc83xx targets, so that
3394 start.S waits for the rest of the SPL to load before
3395 continuing (the hardware starts execution after just
3396 loading the first page rather than the full 4K).
3398 CONFIG_SPL_SKIP_RELOCATE
3399 Avoid SPL relocation
3401 CONFIG_SPL_NAND_BASE
3402 Include nand_base.c in the SPL. Requires
3403 CONFIG_SPL_NAND_DRIVERS.
3405 CONFIG_SPL_NAND_DRIVERS
3406 SPL uses normal NAND drivers, not minimal drivers.
3409 Include standard software ECC in the SPL
3411 CONFIG_SPL_NAND_SIMPLE
3412 Support for NAND boot using simple NAND drivers that
3413 expose the cmd_ctrl() interface.
3415 CONFIG_SPL_MTD_SUPPORT
3416 Support for the MTD subsystem within SPL. Useful for
3417 environment on NAND support within SPL.
3419 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3420 Set for the SPL on PPC mpc8xxx targets, support for
3421 drivers/ddr/fsl/libddr.o in SPL binary.
3423 CONFIG_SPL_COMMON_INIT_DDR
3424 Set for common ddr init with serial presence detect in
3427 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3428 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3429 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3430 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3431 CONFIG_SYS_NAND_ECCBYTES
3432 Defines the size and behavior of the NAND that SPL uses
3435 CONFIG_SPL_NAND_BOOT
3436 Add support NAND boot
3438 CONFIG_SYS_NAND_U_BOOT_OFFS
3439 Location in NAND to read U-Boot from
3441 CONFIG_SYS_NAND_U_BOOT_DST
3442 Location in memory to load U-Boot to
3444 CONFIG_SYS_NAND_U_BOOT_SIZE
3445 Size of image to load
3447 CONFIG_SYS_NAND_U_BOOT_START
3448 Entry point in loaded image to jump to
3450 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3451 Define this if you need to first read the OOB and then the
3452 data. This is used for example on davinci plattforms.
3454 CONFIG_SPL_OMAP3_ID_NAND
3455 Support for an OMAP3-specific set of functions to return the
3456 ID and MFR of the first attached NAND chip, if present.
3458 CONFIG_SPL_SERIAL_SUPPORT
3459 Support for drivers/serial/libserial.o in SPL binary
3461 CONFIG_SPL_SPI_FLASH_SUPPORT
3462 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3464 CONFIG_SPL_SPI_SUPPORT
3465 Support for drivers/spi/libspi.o in SPL binary
3467 CONFIG_SPL_RAM_DEVICE
3468 Support for running image already present in ram, in SPL binary
3470 CONFIG_SPL_LIBGENERIC_SUPPORT
3471 Support for lib/libgeneric.o in SPL binary
3473 CONFIG_SPL_ENV_SUPPORT
3474 Support for the environment operating in SPL binary
3476 CONFIG_SPL_NET_SUPPORT
3477 Support for the net/libnet.o in SPL binary.
3478 It conflicts with SPL env from storage medium specified by
3479 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3482 Image offset to which the SPL should be padded before appending
3483 the SPL payload. By default, this is defined as
3484 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3485 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3486 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3489 Final target image containing SPL and payload. Some SPLs
3490 use an arch-specific makefile fragment instead, for
3491 example if more than one image needs to be produced.
3493 CONFIG_FIT_SPL_PRINT
3494 Printing information about a FIT image adds quite a bit of
3495 code to SPL. So this is normally disabled in SPL. Use this
3496 option to re-enable it. This will affect the output of the
3497 bootm command when booting a FIT image.
3501 Enable building of TPL globally.
3504 Image offset to which the TPL should be padded before appending
3505 the TPL payload. By default, this is defined as
3506 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3507 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3508 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3513 [so far only for SMDK2400 boards]
3515 - Modem support enable:
3516 CONFIG_MODEM_SUPPORT
3518 - RTS/CTS Flow control enable:
3521 - Modem debug support:
3522 CONFIG_MODEM_SUPPORT_DEBUG
3524 Enables debugging stuff (char screen[1024], dbg())
3525 for modem support. Useful only with BDI2000.
3527 - Interrupt support (PPC):
3529 There are common interrupt_init() and timer_interrupt()
3530 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3531 for CPU specific initialization. interrupt_init_cpu()
3532 should set decrementer_count to appropriate value. If
3533 CPU resets decrementer automatically after interrupt
3534 (ppc4xx) it should set decrementer_count to zero.
3535 timer_interrupt() calls timer_interrupt_cpu() for CPU
3536 specific handling. If board has watchdog / status_led
3537 / other_activity_monitor it works automatically from
3538 general timer_interrupt().
3542 In the target system modem support is enabled when a
3543 specific key (key combination) is pressed during
3544 power-on. Otherwise U-Boot will boot normally
3545 (autoboot). The key_pressed() function is called from
3546 board_init(). Currently key_pressed() is a dummy
3547 function, returning 1 and thus enabling modem
3550 If there are no modem init strings in the
3551 environment, U-Boot proceed to autoboot; the
3552 previous output (banner, info printfs) will be
3555 See also: doc/README.Modem
3557 Board initialization settings:
3558 ------------------------------
3560 During Initialization u-boot calls a number of board specific functions
3561 to allow the preparation of board specific prerequisites, e.g. pin setup
3562 before drivers are initialized. To enable these callbacks the
3563 following configuration macros have to be defined. Currently this is
3564 architecture specific, so please check arch/your_architecture/lib/board.c
3565 typically in board_init_f() and board_init_r().
3567 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3568 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3569 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3570 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3572 Configuration Settings:
3573 -----------------------
3575 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3576 Optionally it can be defined to support 64-bit memory commands.
3578 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3579 undefine this when you're short of memory.
3581 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3582 width of the commands listed in the 'help' command output.
3584 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3585 prompt for user input.
3587 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3589 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3591 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3593 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3594 the application (usually a Linux kernel) when it is
3597 - CONFIG_SYS_BAUDRATE_TABLE:
3598 List of legal baudrate settings for this board.
3600 - CONFIG_SYS_CONSOLE_INFO_QUIET
3601 Suppress display of console information at boot.
3603 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3604 If the board specific function
3605 extern int overwrite_console (void);
3606 returns 1, the stdin, stderr and stdout are switched to the
3607 serial port, else the settings in the environment are used.
3609 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3610 Enable the call to overwrite_console().
3612 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3613 Enable overwrite of previous console environment settings.
3615 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3616 Begin and End addresses of the area used by the
3619 - CONFIG_SYS_ALT_MEMTEST:
3620 Enable an alternate, more extensive memory test.
3622 - CONFIG_SYS_MEMTEST_SCRATCH:
3623 Scratch address used by the alternate memory test
3624 You only need to set this if address zero isn't writeable
3626 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3627 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3628 this specified memory area will get subtracted from the top
3629 (end) of RAM and won't get "touched" at all by U-Boot. By
3630 fixing up gd->ram_size the Linux kernel should gets passed
3631 the now "corrected" memory size and won't touch it either.
3632 This should work for arch/ppc and arch/powerpc. Only Linux
3633 board ports in arch/powerpc with bootwrapper support that
3634 recalculate the memory size from the SDRAM controller setup
3635 will have to get fixed in Linux additionally.
3637 This option can be used as a workaround for the 440EPx/GRx
3638 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3641 WARNING: Please make sure that this value is a multiple of
3642 the Linux page size (normally 4k). If this is not the case,
3643 then the end address of the Linux memory will be located at a
3644 non page size aligned address and this could cause major
3647 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3648 Enable temporary baudrate change while serial download
3650 - CONFIG_SYS_SDRAM_BASE:
3651 Physical start address of SDRAM. _Must_ be 0 here.
3653 - CONFIG_SYS_MBIO_BASE:
3654 Physical start address of Motherboard I/O (if using a
3657 - CONFIG_SYS_FLASH_BASE:
3658 Physical start address of Flash memory.
3660 - CONFIG_SYS_MONITOR_BASE:
3661 Physical start address of boot monitor code (set by
3662 make config files to be same as the text base address
3663 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3664 CONFIG_SYS_FLASH_BASE when booting from flash.
3666 - CONFIG_SYS_MONITOR_LEN:
3667 Size of memory reserved for monitor code, used to
3668 determine _at_compile_time_ (!) if the environment is
3669 embedded within the U-Boot image, or in a separate
3672 - CONFIG_SYS_MALLOC_LEN:
3673 Size of DRAM reserved for malloc() use.
3675 - CONFIG_SYS_BOOTM_LEN:
3676 Normally compressed uImages are limited to an
3677 uncompressed size of 8 MBytes. If this is not enough,
3678 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3679 to adjust this setting to your needs.
3681 - CONFIG_SYS_BOOTMAPSZ:
3682 Maximum size of memory mapped by the startup code of
3683 the Linux kernel; all data that must be processed by
3684 the Linux kernel (bd_info, boot arguments, FDT blob if
3685 used) must be put below this limit, unless "bootm_low"
3686 environment variable is defined and non-zero. In such case
3687 all data for the Linux kernel must be between "bootm_low"
3688 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3689 variable "bootm_mapsize" will override the value of
3690 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3691 then the value in "bootm_size" will be used instead.
3693 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3694 Enable initrd_high functionality. If defined then the
3695 initrd_high feature is enabled and the bootm ramdisk subcommand
3698 - CONFIG_SYS_BOOT_GET_CMDLINE:
3699 Enables allocating and saving kernel cmdline in space between
3700 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3702 - CONFIG_SYS_BOOT_GET_KBD:
3703 Enables allocating and saving a kernel copy of the bd_info in
3704 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3706 - CONFIG_SYS_MAX_FLASH_BANKS:
3707 Max number of Flash memory banks
3709 - CONFIG_SYS_MAX_FLASH_SECT:
3710 Max number of sectors on a Flash chip
3712 - CONFIG_SYS_FLASH_ERASE_TOUT:
3713 Timeout for Flash erase operations (in ms)
3715 - CONFIG_SYS_FLASH_WRITE_TOUT:
3716 Timeout for Flash write operations (in ms)
3718 - CONFIG_SYS_FLASH_LOCK_TOUT
3719 Timeout for Flash set sector lock bit operation (in ms)
3721 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3722 Timeout for Flash clear lock bits operation (in ms)
3724 - CONFIG_SYS_FLASH_PROTECTION
3725 If defined, hardware flash sectors protection is used
3726 instead of U-Boot software protection.
3728 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3730 Enable TFTP transfers directly to flash memory;
3731 without this option such a download has to be
3732 performed in two steps: (1) download to RAM, and (2)
3733 copy from RAM to flash.
3735 The two-step approach is usually more reliable, since
3736 you can check if the download worked before you erase
3737 the flash, but in some situations (when system RAM is
3738 too limited to allow for a temporary copy of the
3739 downloaded image) this option may be very useful.
3741 - CONFIG_SYS_FLASH_CFI:
3742 Define if the flash driver uses extra elements in the
3743 common flash structure for storing flash geometry.
3745 - CONFIG_FLASH_CFI_DRIVER
3746 This option also enables the building of the cfi_flash driver
3747 in the drivers directory
3749 - CONFIG_FLASH_CFI_MTD
3750 This option enables the building of the cfi_mtd driver
3751 in the drivers directory. The driver exports CFI flash
3754 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3755 Use buffered writes to flash.
3757 - CONFIG_FLASH_SPANSION_S29WS_N
3758 s29ws-n MirrorBit flash has non-standard addresses for buffered
3761 - CONFIG_SYS_FLASH_QUIET_TEST
3762 If this option is defined, the common CFI flash doesn't
3763 print it's warning upon not recognized FLASH banks. This
3764 is useful, if some of the configured banks are only
3765 optionally available.
3767 - CONFIG_FLASH_SHOW_PROGRESS
3768 If defined (must be an integer), print out countdown
3769 digits and dots. Recommended value: 45 (9..1) for 80
3770 column displays, 15 (3..1) for 40 column displays.
3772 - CONFIG_FLASH_VERIFY
3773 If defined, the content of the flash (destination) is compared
3774 against the source after the write operation. An error message
3775 will be printed when the contents are not identical.
3776 Please note that this option is useless in nearly all cases,
3777 since such flash programming errors usually are detected earlier
3778 while unprotecting/erasing/programming. Please only enable
3779 this option if you really know what you are doing.
3781 - CONFIG_SYS_RX_ETH_BUFFER:
3782 Defines the number of Ethernet receive buffers. On some
3783 Ethernet controllers it is recommended to set this value
3784 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3785 buffers can be full shortly after enabling the interface
3786 on high Ethernet traffic.
3787 Defaults to 4 if not defined.
3789 - CONFIG_ENV_MAX_ENTRIES
3791 Maximum number of entries in the hash table that is used
3792 internally to store the environment settings. The default
3793 setting is supposed to be generous and should work in most
3794 cases. This setting can be used to tune behaviour; see
3795 lib/hashtable.c for details.
3797 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3798 - CONFIG_ENV_FLAGS_LIST_STATIC
3799 Enable validation of the values given to environment variables when
3800 calling env set. Variables can be restricted to only decimal,
3801 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3802 the variables can also be restricted to IP address or MAC address.
3804 The format of the list is:
3805 type_attribute = [s|d|x|b|i|m]
3806 access_atribute = [a|r|o|c]
3807 attributes = type_attribute[access_atribute]
3808 entry = variable_name[:attributes]
3811 The type attributes are:
3812 s - String (default)
3815 b - Boolean ([1yYtT|0nNfF])
3819 The access attributes are:
3825 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3826 Define this to a list (string) to define the ".flags"
3827 envirnoment variable in the default or embedded environment.
3829 - CONFIG_ENV_FLAGS_LIST_STATIC
3830 Define this to a list (string) to define validation that
3831 should be done if an entry is not found in the ".flags"
3832 environment variable. To override a setting in the static
3833 list, simply add an entry for the same variable name to the
3836 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3837 If defined, don't allow the -f switch to env set override variable
3840 - CONFIG_SYS_GENERIC_BOARD
3841 This selects the architecture-generic board system instead of the
3842 architecture-specific board files. It is intended to move boards
3843 to this new framework over time. Defining this will disable the
3844 arch/foo/lib/board.c file and use common/board_f.c and
3845 common/board_r.c instead. To use this option your architecture
3846 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3847 its config.mk file). If you find problems enabling this option on
3848 your board please report the problem and send patches!
3850 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3851 This is set by OMAP boards for the max time that reset should
3852 be asserted. See doc/README.omap-reset-time for details on how
3853 the value can be calulated on a given board.
3855 The following definitions that deal with the placement and management
3856 of environment data (variable area); in general, we support the
3857 following configurations:
3859 - CONFIG_BUILD_ENVCRC:
3861 Builds up envcrc with the target environment so that external utils
3862 may easily extract it and embed it in final U-Boot images.
3864 - CONFIG_ENV_IS_IN_FLASH:
3866 Define this if the environment is in flash memory.
3868 a) The environment occupies one whole flash sector, which is
3869 "embedded" in the text segment with the U-Boot code. This
3870 happens usually with "bottom boot sector" or "top boot
3871 sector" type flash chips, which have several smaller
3872 sectors at the start or the end. For instance, such a
3873 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3874 such a case you would place the environment in one of the
3875 4 kB sectors - with U-Boot code before and after it. With
3876 "top boot sector" type flash chips, you would put the
3877 environment in one of the last sectors, leaving a gap
3878 between U-Boot and the environment.
3880 - CONFIG_ENV_OFFSET:
3882 Offset of environment data (variable area) to the
3883 beginning of flash memory; for instance, with bottom boot
3884 type flash chips the second sector can be used: the offset
3885 for this sector is given here.
3887 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3891 This is just another way to specify the start address of
3892 the flash sector containing the environment (instead of
3895 - CONFIG_ENV_SECT_SIZE:
3897 Size of the sector containing the environment.
3900 b) Sometimes flash chips have few, equal sized, BIG sectors.
3901 In such a case you don't want to spend a whole sector for
3906 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3907 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3908 of this flash sector for the environment. This saves
3909 memory for the RAM copy of the environment.
3911 It may also save flash memory if you decide to use this
3912 when your environment is "embedded" within U-Boot code,
3913 since then the remainder of the flash sector could be used
3914 for U-Boot code. It should be pointed out that this is
3915 STRONGLY DISCOURAGED from a robustness point of view:
3916 updating the environment in flash makes it always
3917 necessary to erase the WHOLE sector. If something goes
3918 wrong before the contents has been restored from a copy in
3919 RAM, your target system will be dead.
3921 - CONFIG_ENV_ADDR_REDUND
3922 CONFIG_ENV_SIZE_REDUND
3924 These settings describe a second storage area used to hold
3925 a redundant copy of the environment data, so that there is
3926 a valid backup copy in case there is a power failure during
3927 a "saveenv" operation.
3929 BE CAREFUL! Any changes to the flash layout, and some changes to the
3930 source code will make it necessary to adapt <board>/u-boot.lds*
3934 - CONFIG_ENV_IS_IN_NVRAM:
3936 Define this if you have some non-volatile memory device
3937 (NVRAM, battery buffered SRAM) which you want to use for the
3943 These two #defines are used to determine the memory area you
3944 want to use for environment. It is assumed that this memory
3945 can just be read and written to, without any special
3948 BE CAREFUL! The first access to the environment happens quite early
3949 in U-Boot initalization (when we try to get the setting of for the
3950 console baudrate). You *MUST* have mapped your NVRAM area then, or
3953 Please note that even with NVRAM we still use a copy of the
3954 environment in RAM: we could work on NVRAM directly, but we want to
3955 keep settings there always unmodified except somebody uses "saveenv"
3956 to save the current settings.
3959 - CONFIG_ENV_IS_IN_EEPROM:
3961 Use this if you have an EEPROM or similar serial access
3962 device and a driver for it.
3964 - CONFIG_ENV_OFFSET:
3967 These two #defines specify the offset and size of the
3968 environment area within the total memory of your EEPROM.
3970 - CONFIG_SYS_I2C_EEPROM_ADDR:
3971 If defined, specified the chip address of the EEPROM device.
3972 The default address is zero.
3974 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3975 If defined, the number of bits used to address bytes in a
3976 single page in the EEPROM device. A 64 byte page, for example
3977 would require six bits.
3979 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3980 If defined, the number of milliseconds to delay between
3981 page writes. The default is zero milliseconds.
3983 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3984 The length in bytes of the EEPROM memory array address. Note
3985 that this is NOT the chip address length!
3987 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3988 EEPROM chips that implement "address overflow" are ones
3989 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3990 address and the extra bits end up in the "chip address" bit
3991 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3994 Note that we consider the length of the address field to
3995 still be one byte because the extra address bits are hidden
3996 in the chip address.
3998 - CONFIG_SYS_EEPROM_SIZE:
3999 The size in bytes of the EEPROM device.
4001 - CONFIG_ENV_EEPROM_IS_ON_I2C
4002 define this, if you have I2C and SPI activated, and your
4003 EEPROM, which holds the environment, is on the I2C bus.
4005 - CONFIG_I2C_ENV_EEPROM_BUS
4006 if you have an Environment on an EEPROM reached over
4007 I2C muxes, you can define here, how to reach this
4008 EEPROM. For example:
4010 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4012 EEPROM which holds the environment, is reached over
4013 a pca9547 i2c mux with address 0x70, channel 3.
4015 - CONFIG_ENV_IS_IN_DATAFLASH:
4017 Define this if you have a DataFlash memory device which you
4018 want to use for the environment.
4020 - CONFIG_ENV_OFFSET:
4024 These three #defines specify the offset and size of the
4025 environment area within the total memory of your DataFlash placed
4026 at the specified address.
4028 - CONFIG_ENV_IS_IN_REMOTE:
4030 Define this if you have a remote memory space which you
4031 want to use for the local device's environment.
4036 These two #defines specify the address and size of the
4037 environment area within the remote memory space. The
4038 local device can get the environment from remote memory
4039 space by SRIO or PCIE links.
4041 BE CAREFUL! For some special cases, the local device can not use
4042 "saveenv" command. For example, the local device will get the
4043 environment stored in a remote NOR flash by SRIO or PCIE link,
4044 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4046 - CONFIG_ENV_IS_IN_NAND:
4048 Define this if you have a NAND device which you want to use
4049 for the environment.
4051 - CONFIG_ENV_OFFSET:
4054 These two #defines specify the offset and size of the environment
4055 area within the first NAND device. CONFIG_ENV_OFFSET must be
4056 aligned to an erase block boundary.
4058 - CONFIG_ENV_OFFSET_REDUND (optional):
4060 This setting describes a second storage area of CONFIG_ENV_SIZE
4061 size used to hold a redundant copy of the environment data, so
4062 that there is a valid backup copy in case there is a power failure
4063 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4064 aligned to an erase block boundary.
4066 - CONFIG_ENV_RANGE (optional):
4068 Specifies the length of the region in which the environment
4069 can be written. This should be a multiple of the NAND device's
4070 block size. Specifying a range with more erase blocks than
4071 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4072 the range to be avoided.
4074 - CONFIG_ENV_OFFSET_OOB (optional):
4076 Enables support for dynamically retrieving the offset of the
4077 environment from block zero's out-of-band data. The
4078 "nand env.oob" command can be used to record this offset.
4079 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4080 using CONFIG_ENV_OFFSET_OOB.
4082 - CONFIG_NAND_ENV_DST
4084 Defines address in RAM to which the nand_spl code should copy the
4085 environment. If redundant environment is used, it will be copied to
4086 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4088 - CONFIG_ENV_IS_IN_UBI:
4090 Define this if you have an UBI volume that you want to use for the
4091 environment. This has the benefit of wear-leveling the environment
4092 accesses, which is important on NAND.
4094 - CONFIG_ENV_UBI_PART:
4096 Define this to a string that is the mtd partition containing the UBI.
4098 - CONFIG_ENV_UBI_VOLUME:
4100 Define this to the name of the volume that you want to store the
4103 - CONFIG_ENV_UBI_VOLUME_REDUND:
4105 Define this to the name of another volume to store a second copy of
4106 the environment in. This will enable redundant environments in UBI.
4107 It is assumed that both volumes are in the same MTD partition.
4109 - CONFIG_UBI_SILENCE_MSG
4110 - CONFIG_UBIFS_SILENCE_MSG
4112 You will probably want to define these to avoid a really noisy system
4113 when storing the env in UBI.
4115 - CONFIG_ENV_IS_IN_MMC:
4117 Define this if you have an MMC device which you want to use for the
4120 - CONFIG_SYS_MMC_ENV_DEV:
4122 Specifies which MMC device the environment is stored in.
4124 - CONFIG_SYS_MMC_ENV_PART (optional):
4126 Specifies which MMC partition the environment is stored in. If not
4127 set, defaults to partition 0, the user area. Common values might be
4128 1 (first MMC boot partition), 2 (second MMC boot partition).
4130 - CONFIG_ENV_OFFSET:
4133 These two #defines specify the offset and size of the environment
4134 area within the specified MMC device.
4136 If offset is positive (the usual case), it is treated as relative to
4137 the start of the MMC partition. If offset is negative, it is treated
4138 as relative to the end of the MMC partition. This can be useful if
4139 your board may be fitted with different MMC devices, which have
4140 different sizes for the MMC partitions, and you always want the
4141 environment placed at the very end of the partition, to leave the
4142 maximum possible space before it, to store other data.
4144 These two values are in units of bytes, but must be aligned to an
4145 MMC sector boundary.
4147 - CONFIG_ENV_OFFSET_REDUND (optional):
4149 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4150 hold a redundant copy of the environment data. This provides a
4151 valid backup copy in case the other copy is corrupted, e.g. due
4152 to a power failure during a "saveenv" operation.
4154 This value may also be positive or negative; this is handled in the
4155 same way as CONFIG_ENV_OFFSET.
4157 This value is also in units of bytes, but must also be aligned to
4158 an MMC sector boundary.
4160 - CONFIG_ENV_SIZE_REDUND (optional):
4162 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4163 set. If this value is set, it must be set to the same value as
4166 - CONFIG_SYS_SPI_INIT_OFFSET
4168 Defines offset to the initial SPI buffer area in DPRAM. The
4169 area is used at an early stage (ROM part) if the environment
4170 is configured to reside in the SPI EEPROM: We need a 520 byte
4171 scratch DPRAM area. It is used between the two initialization
4172 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4173 to be a good choice since it makes it far enough from the
4174 start of the data area as well as from the stack pointer.
4176 Please note that the environment is read-only until the monitor
4177 has been relocated to RAM and a RAM copy of the environment has been
4178 created; also, when using EEPROM you will have to use getenv_f()
4179 until then to read environment variables.
4181 The environment is protected by a CRC32 checksum. Before the monitor
4182 is relocated into RAM, as a result of a bad CRC you will be working
4183 with the compiled-in default environment - *silently*!!! [This is
4184 necessary, because the first environment variable we need is the
4185 "baudrate" setting for the console - if we have a bad CRC, we don't
4186 have any device yet where we could complain.]
4188 Note: once the monitor has been relocated, then it will complain if
4189 the default environment is used; a new CRC is computed as soon as you
4190 use the "saveenv" command to store a valid environment.
4192 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4193 Echo the inverted Ethernet link state to the fault LED.
4195 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4196 also needs to be defined.
4198 - CONFIG_SYS_FAULT_MII_ADDR:
4199 MII address of the PHY to check for the Ethernet link state.
4201 - CONFIG_NS16550_MIN_FUNCTIONS:
4202 Define this if you desire to only have use of the NS16550_init
4203 and NS16550_putc functions for the serial driver located at
4204 drivers/serial/ns16550.c. This option is useful for saving
4205 space for already greatly restricted images, including but not
4206 limited to NAND_SPL configurations.
4208 - CONFIG_DISPLAY_BOARDINFO
4209 Display information about the board that U-Boot is running on
4210 when U-Boot starts up. The board function checkboard() is called
4213 - CONFIG_DISPLAY_BOARDINFO_LATE
4214 Similar to the previous option, but display this information
4215 later, once stdio is running and output goes to the LCD, if
4218 Low Level (hardware related) configuration options:
4219 ---------------------------------------------------
4221 - CONFIG_SYS_CACHELINE_SIZE:
4222 Cache Line Size of the CPU.
4224 - CONFIG_SYS_DEFAULT_IMMR:
4225 Default address of the IMMR after system reset.
4227 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4228 and RPXsuper) to be able to adjust the position of
4229 the IMMR register after a reset.
4231 - CONFIG_SYS_CCSRBAR_DEFAULT:
4232 Default (power-on reset) physical address of CCSR on Freescale
4235 - CONFIG_SYS_CCSRBAR:
4236 Virtual address of CCSR. On a 32-bit build, this is typically
4237 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4239 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4240 for cross-platform code that uses that macro instead.
4242 - CONFIG_SYS_CCSRBAR_PHYS:
4243 Physical address of CCSR. CCSR can be relocated to a new
4244 physical address, if desired. In this case, this macro should
4245 be set to that address. Otherwise, it should be set to the
4246 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4247 is typically relocated on 36-bit builds. It is recommended
4248 that this macro be defined via the _HIGH and _LOW macros:
4250 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4251 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4253 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4254 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4255 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4256 used in assembly code, so it must not contain typecasts or
4257 integer size suffixes (e.g. "ULL").
4259 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4260 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4261 used in assembly code, so it must not contain typecasts or
4262 integer size suffixes (e.g. "ULL").
4264 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4265 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4266 forced to a value that ensures that CCSR is not relocated.
4268 - Floppy Disk Support:
4269 CONFIG_SYS_FDC_DRIVE_NUMBER
4271 the default drive number (default value 0)
4273 CONFIG_SYS_ISA_IO_STRIDE
4275 defines the spacing between FDC chipset registers
4278 CONFIG_SYS_ISA_IO_OFFSET
4280 defines the offset of register from address. It
4281 depends on which part of the data bus is connected to
4282 the FDC chipset. (default value 0)
4284 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4285 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4288 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4289 fdc_hw_init() is called at the beginning of the FDC
4290 setup. fdc_hw_init() must be provided by the board
4291 source code. It is used to make hardware dependant
4295 Most IDE controllers were designed to be connected with PCI
4296 interface. Only few of them were designed for AHB interface.
4297 When software is doing ATA command and data transfer to
4298 IDE devices through IDE-AHB controller, some additional
4299 registers accessing to these kind of IDE-AHB controller
4302 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4303 DO NOT CHANGE unless you know exactly what you're
4304 doing! (11-4) [MPC8xx/82xx systems only]
4306 - CONFIG_SYS_INIT_RAM_ADDR:
4308 Start address of memory area that can be used for
4309 initial data and stack; please note that this must be
4310 writable memory that is working WITHOUT special
4311 initialization, i. e. you CANNOT use normal RAM which
4312 will become available only after programming the
4313 memory controller and running certain initialization
4316 U-Boot uses the following memory types:
4317 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4318 - MPC824X: data cache
4319 - PPC4xx: data cache
4321 - CONFIG_SYS_GBL_DATA_OFFSET:
4323 Offset of the initial data structure in the memory
4324 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4325 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4326 data is located at the end of the available space
4327 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4328 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4329 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4330 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4333 On the MPC824X (or other systems that use the data
4334 cache for initial memory) the address chosen for
4335 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4336 point to an otherwise UNUSED address space between
4337 the top of RAM and the start of the PCI space.
4339 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4341 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4343 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4345 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4347 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4349 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4351 - CONFIG_SYS_OR_TIMING_SDRAM:
4354 - CONFIG_SYS_MAMR_PTA:
4355 periodic timer for refresh
4357 - CONFIG_SYS_DER: Debug Event Register (37-47)
4359 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4360 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4361 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4362 CONFIG_SYS_BR1_PRELIM:
4363 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4365 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4366 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4367 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4368 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4370 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4371 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4372 Machine Mode Register and Memory Periodic Timer
4373 Prescaler definitions (SDRAM timing)
4375 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4376 enable I2C microcode relocation patch (MPC8xx);
4377 define relocation offset in DPRAM [DSP2]
4379 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4380 enable SMC microcode relocation patch (MPC8xx);
4381 define relocation offset in DPRAM [SMC1]
4383 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4384 enable SPI microcode relocation patch (MPC8xx);
4385 define relocation offset in DPRAM [SCC4]
4387 - CONFIG_SYS_USE_OSCCLK:
4388 Use OSCM clock mode on MBX8xx board. Be careful,
4389 wrong setting might damage your board. Read
4390 doc/README.MBX before setting this variable!
4392 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4393 Offset of the bootmode word in DPRAM used by post
4394 (Power On Self Tests). This definition overrides
4395 #define'd default value in commproc.h resp.
4398 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4399 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4400 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4401 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4402 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4403 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4404 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4405 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4406 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4408 - CONFIG_PCI_DISABLE_PCIE:
4409 Disable PCI-Express on systems where it is supported but not
4412 - CONFIG_PCI_ENUM_ONLY
4413 Only scan through and get the devices on the busses.
4414 Don't do any setup work, presumably because someone or
4415 something has already done it, and we don't need to do it
4416 a second time. Useful for platforms that are pre-booted
4417 by coreboot or similar.
4419 - CONFIG_PCI_INDIRECT_BRIDGE:
4420 Enable support for indirect PCI bridges.
4423 Chip has SRIO or not
4426 Board has SRIO 1 port available
4429 Board has SRIO 2 port available
4431 - CONFIG_SRIO_PCIE_BOOT_MASTER
4432 Board can support master function for Boot from SRIO and PCIE
4434 - CONFIG_SYS_SRIOn_MEM_VIRT:
4435 Virtual Address of SRIO port 'n' memory region
4437 - CONFIG_SYS_SRIOn_MEM_PHYS:
4438 Physical Address of SRIO port 'n' memory region
4440 - CONFIG_SYS_SRIOn_MEM_SIZE:
4441 Size of SRIO port 'n' memory region
4443 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4444 Defined to tell the NAND controller that the NAND chip is using
4446 Not all NAND drivers use this symbol.
4447 Example of drivers that use it:
4448 - drivers/mtd/nand/ndfc.c
4449 - drivers/mtd/nand/mxc_nand.c
4451 - CONFIG_SYS_NDFC_EBC0_CFG
4452 Sets the EBC0_CFG register for the NDFC. If not defined
4453 a default value will be used.
4456 Get DDR timing information from an I2C EEPROM. Common
4457 with pluggable memory modules such as SODIMMs
4460 I2C address of the SPD EEPROM
4462 - CONFIG_SYS_SPD_BUS_NUM
4463 If SPD EEPROM is on an I2C bus other than the first
4464 one, specify here. Note that the value must resolve
4465 to something your driver can deal with.
4467 - CONFIG_SYS_DDR_RAW_TIMING
4468 Get DDR timing information from other than SPD. Common with
4469 soldered DDR chips onboard without SPD. DDR raw timing
4470 parameters are extracted from datasheet and hard-coded into
4471 header files or board specific files.
4473 - CONFIG_FSL_DDR_INTERACTIVE
4474 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4476 - CONFIG_SYS_83XX_DDR_USES_CS0
4477 Only for 83xx systems. If specified, then DDR should
4478 be configured using CS0 and CS1 instead of CS2 and CS3.
4480 - CONFIG_ETHER_ON_FEC[12]
4481 Define to enable FEC[12] on a 8xx series processor.
4483 - CONFIG_FEC[12]_PHY
4484 Define to the hardcoded PHY address which corresponds
4485 to the given FEC; i. e.
4486 #define CONFIG_FEC1_PHY 4
4487 means that the PHY with address 4 is connected to FEC1
4489 When set to -1, means to probe for first available.
4491 - CONFIG_FEC[12]_PHY_NORXERR
4492 The PHY does not have a RXERR line (RMII only).
4493 (so program the FEC to ignore it).
4496 Enable RMII mode for all FECs.
4497 Note that this is a global option, we can't
4498 have one FEC in standard MII mode and another in RMII mode.
4500 - CONFIG_CRC32_VERIFY
4501 Add a verify option to the crc32 command.
4504 => crc32 -v <address> <count> <crc32>
4506 Where address/count indicate a memory area
4507 and crc32 is the correct crc32 which the
4511 Add the "loopw" memory command. This only takes effect if
4512 the memory commands are activated globally (CONFIG_CMD_MEM).
4515 Add the "mdc" and "mwc" memory commands. These are cyclic
4520 This command will print 4 bytes (10,11,12,13) each 500 ms.
4522 => mwc.l 100 12345678 10
4523 This command will write 12345678 to address 100 all 10 ms.
4525 This only takes effect if the memory commands are activated
4526 globally (CONFIG_CMD_MEM).
4528 - CONFIG_SKIP_LOWLEVEL_INIT
4529 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4530 low level initializations (like setting up the memory
4531 controller) are omitted and/or U-Boot does not
4532 relocate itself into RAM.
4534 Normally this variable MUST NOT be defined. The only
4535 exception is when U-Boot is loaded (to RAM) by some
4536 other boot loader or by a debugger which performs
4537 these initializations itself.
4540 Modifies the behaviour of start.S when compiling a loader
4541 that is executed before the actual U-Boot. E.g. when
4542 compiling a NAND SPL.
4545 Modifies the behaviour of start.S when compiling a loader
4546 that is executed after the SPL and before the actual U-Boot.
4547 It is loaded by the SPL.
4549 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4550 Only for 85xx systems. If this variable is specified, the section
4551 .resetvec is not kept and the section .bootpg is placed in the
4552 previous 4k of the .text section.
4554 - CONFIG_ARCH_MAP_SYSMEM
4555 Generally U-Boot (and in particular the md command) uses
4556 effective address. It is therefore not necessary to regard
4557 U-Boot address as virtual addresses that need to be translated
4558 to physical addresses. However, sandbox requires this, since
4559 it maintains its own little RAM buffer which contains all
4560 addressable memory. This option causes some memory accesses
4561 to be mapped through map_sysmem() / unmap_sysmem().
4563 - CONFIG_USE_ARCH_MEMCPY
4564 CONFIG_USE_ARCH_MEMSET
4565 If these options are used a optimized version of memcpy/memset will
4566 be used if available. These functions may be faster under some
4567 conditions but may increase the binary size.
4569 - CONFIG_X86_RESET_VECTOR
4570 If defined, the x86 reset vector code is included. This is not
4571 needed when U-Boot is running from Coreboot.
4574 Defines the MPU clock speed (in MHz).
4576 NOTE : currently only supported on AM335x platforms.
4578 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4579 Enables the RTC32K OSC on AM33xx based plattforms
4581 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4582 Option to disable subpage write in NAND driver
4583 driver that uses this:
4584 drivers/mtd/nand/davinci_nand.c
4586 Freescale QE/FMAN Firmware Support:
4587 -----------------------------------
4589 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4590 loading of "firmware", which is encoded in the QE firmware binary format.
4591 This firmware often needs to be loaded during U-Boot booting, so macros
4592 are used to identify the storage device (NOR flash, SPI, etc) and the address
4595 - CONFIG_SYS_FMAN_FW_ADDR
4596 The address in the storage device where the FMAN microcode is located. The
4597 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4600 - CONFIG_SYS_QE_FW_ADDR
4601 The address in the storage device where the QE microcode is located. The
4602 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4605 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4606 The maximum possible size of the firmware. The firmware binary format
4607 has a field that specifies the actual size of the firmware, but it
4608 might not be possible to read any part of the firmware unless some
4609 local storage is allocated to hold the entire firmware first.
4611 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4612 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4613 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4614 virtual address in NOR flash.
4616 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4617 Specifies that QE/FMAN firmware is located in NAND flash.
4618 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4620 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4621 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4622 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4624 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4625 Specifies that QE/FMAN firmware is located on the primary SPI
4626 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4628 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4629 Specifies that QE/FMAN firmware is located in the remote (master)
4630 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4631 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4632 window->master inbound window->master LAW->the ucode address in
4633 master's memory space.
4635 Building the Software:
4636 ======================
4638 Building U-Boot has been tested in several native build environments
4639 and in many different cross environments. Of course we cannot support
4640 all possibly existing versions of cross development tools in all
4641 (potentially obsolete) versions. In case of tool chain problems we
4642 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4643 which is extensively used to build and test U-Boot.
4645 If you are not using a native environment, it is assumed that you
4646 have GNU cross compiling tools available in your path. In this case,
4647 you must set the environment variable CROSS_COMPILE in your shell.
4648 Note that no changes to the Makefile or any other source files are
4649 necessary. For example using the ELDK on a 4xx CPU, please enter:
4651 $ CROSS_COMPILE=ppc_4xx-
4652 $ export CROSS_COMPILE
4654 Note: If you wish to generate Windows versions of the utilities in
4655 the tools directory you can use the MinGW toolchain
4656 (http://www.mingw.org). Set your HOST tools to the MinGW
4657 toolchain and execute 'make tools'. For example:
4659 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4661 Binaries such as tools/mkimage.exe will be created which can
4662 be executed on computers running Windows.
4664 U-Boot is intended to be simple to build. After installing the
4665 sources you must configure U-Boot for one specific board type. This
4670 where "NAME_config" is the name of one of the existing configu-
4671 rations; see boards.cfg for supported names.
4673 Note: for some board special configuration names may exist; check if
4674 additional information is available from the board vendor; for
4675 instance, the TQM823L systems are available without (standard)
4676 or with LCD support. You can select such additional "features"
4677 when choosing the configuration, i. e.
4680 - will configure for a plain TQM823L, i. e. no LCD support
4682 make TQM823L_LCD_config
4683 - will configure for a TQM823L with U-Boot console on LCD
4688 Finally, type "make all", and you should get some working U-Boot
4689 images ready for download to / installation on your system:
4691 - "u-boot.bin" is a raw binary image
4692 - "u-boot" is an image in ELF binary format
4693 - "u-boot.srec" is in Motorola S-Record format
4695 By default the build is performed locally and the objects are saved
4696 in the source directory. One of the two methods can be used to change
4697 this behavior and build U-Boot to some external directory:
4699 1. Add O= to the make command line invocations:
4701 make O=/tmp/build distclean
4702 make O=/tmp/build NAME_config
4703 make O=/tmp/build all
4705 2. Set environment variable BUILD_DIR to point to the desired location:
4707 export BUILD_DIR=/tmp/build
4712 Note that the command line "O=" setting overrides the BUILD_DIR environment
4716 Please be aware that the Makefiles assume you are using GNU make, so
4717 for instance on NetBSD you might need to use "gmake" instead of
4721 If the system board that you have is not listed, then you will need
4722 to port U-Boot to your hardware platform. To do this, follow these
4725 1. Add a new configuration option for your board to the toplevel
4726 "boards.cfg" file, using the existing entries as examples.
4727 Follow the instructions there to keep the boards in order.
4728 2. Create a new directory to hold your board specific code. Add any
4729 files you need. In your board directory, you will need at least
4730 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4731 3. Create a new configuration file "include/configs/<board>.h" for
4733 3. If you're porting U-Boot to a new CPU, then also create a new
4734 directory to hold your CPU specific code. Add any files you need.
4735 4. Run "make <board>_config" with your new name.
4736 5. Type "make", and you should get a working "u-boot.srec" file
4737 to be installed on your target system.
4738 6. Debug and solve any problems that might arise.
4739 [Of course, this last step is much harder than it sounds.]
4742 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4743 ==============================================================
4745 If you have modified U-Boot sources (for instance added a new board
4746 or support for new devices, a new CPU, etc.) you are expected to
4747 provide feedback to the other developers. The feedback normally takes
4748 the form of a "patch", i. e. a context diff against a certain (latest
4749 official or latest in the git repository) version of U-Boot sources.
4751 But before you submit such a patch, please verify that your modifi-
4752 cation did not break existing code. At least make sure that *ALL* of
4753 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4754 just run the "MAKEALL" script, which will configure and build U-Boot
4755 for ALL supported system. Be warned, this will take a while. You can
4756 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4757 environment variable to the script, i. e. to use the ELDK cross tools
4760 CROSS_COMPILE=ppc_8xx- MAKEALL
4762 or to build on a native PowerPC system you can type
4764 CROSS_COMPILE=' ' MAKEALL
4766 When using the MAKEALL script, the default behaviour is to build
4767 U-Boot in the source directory. This location can be changed by
4768 setting the BUILD_DIR environment variable. Also, for each target
4769 built, the MAKEALL script saves two log files (<target>.ERR and
4770 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4771 location can be changed by setting the MAKEALL_LOGDIR environment
4772 variable. For example:
4774 export BUILD_DIR=/tmp/build
4775 export MAKEALL_LOGDIR=/tmp/log
4776 CROSS_COMPILE=ppc_8xx- MAKEALL
4778 With the above settings build objects are saved in the /tmp/build,
4779 log files are saved in the /tmp/log and the source tree remains clean
4780 during the whole build process.
4783 See also "U-Boot Porting Guide" below.
4786 Monitor Commands - Overview:
4787 ============================
4789 go - start application at address 'addr'
4790 run - run commands in an environment variable
4791 bootm - boot application image from memory
4792 bootp - boot image via network using BootP/TFTP protocol
4793 bootz - boot zImage from memory
4794 tftpboot- boot image via network using TFTP protocol
4795 and env variables "ipaddr" and "serverip"
4796 (and eventually "gatewayip")
4797 tftpput - upload a file via network using TFTP protocol
4798 rarpboot- boot image via network using RARP/TFTP protocol
4799 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4800 loads - load S-Record file over serial line
4801 loadb - load binary file over serial line (kermit mode)
4803 mm - memory modify (auto-incrementing)
4804 nm - memory modify (constant address)
4805 mw - memory write (fill)
4807 cmp - memory compare
4808 crc32 - checksum calculation
4809 i2c - I2C sub-system
4810 sspi - SPI utility commands
4811 base - print or set address offset
4812 printenv- print environment variables
4813 setenv - set environment variables
4814 saveenv - save environment variables to persistent storage
4815 protect - enable or disable FLASH write protection
4816 erase - erase FLASH memory
4817 flinfo - print FLASH memory information
4818 nand - NAND memory operations (see doc/README.nand)
4819 bdinfo - print Board Info structure
4820 iminfo - print header information for application image
4821 coninfo - print console devices and informations
4822 ide - IDE sub-system
4823 loop - infinite loop on address range
4824 loopw - infinite write loop on address range
4825 mtest - simple RAM test
4826 icache - enable or disable instruction cache
4827 dcache - enable or disable data cache
4828 reset - Perform RESET of the CPU
4829 echo - echo args to console
4830 version - print monitor version
4831 help - print online help
4832 ? - alias for 'help'
4835 Monitor Commands - Detailed Description:
4836 ========================================
4840 For now: just type "help <command>".
4843 Environment Variables:
4844 ======================
4846 U-Boot supports user configuration using Environment Variables which
4847 can be made persistent by saving to Flash memory.
4849 Environment Variables are set using "setenv", printed using
4850 "printenv", and saved to Flash using "saveenv". Using "setenv"
4851 without a value can be used to delete a variable from the
4852 environment. As long as you don't save the environment you are
4853 working with an in-memory copy. In case the Flash area containing the
4854 environment is erased by accident, a default environment is provided.
4856 Some configuration options can be set using Environment Variables.
4858 List of environment variables (most likely not complete):
4860 baudrate - see CONFIG_BAUDRATE
4862 bootdelay - see CONFIG_BOOTDELAY
4864 bootcmd - see CONFIG_BOOTCOMMAND
4866 bootargs - Boot arguments when booting an RTOS image
4868 bootfile - Name of the image to load with TFTP
4870 bootm_low - Memory range available for image processing in the bootm
4871 command can be restricted. This variable is given as
4872 a hexadecimal number and defines lowest address allowed
4873 for use by the bootm command. See also "bootm_size"
4874 environment variable. Address defined by "bootm_low" is
4875 also the base of the initial memory mapping for the Linux
4876 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4879 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4880 This variable is given as a hexadecimal number and it
4881 defines the size of the memory region starting at base
4882 address bootm_low that is accessible by the Linux kernel
4883 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4884 as the default value if it is defined, and bootm_size is
4887 bootm_size - Memory range available for image processing in the bootm
4888 command can be restricted. This variable is given as
4889 a hexadecimal number and defines the size of the region
4890 allowed for use by the bootm command. See also "bootm_low"
4891 environment variable.
4893 updatefile - Location of the software update file on a TFTP server, used
4894 by the automatic software update feature. Please refer to
4895 documentation in doc/README.update for more details.
4897 autoload - if set to "no" (any string beginning with 'n'),
4898 "bootp" will just load perform a lookup of the
4899 configuration from the BOOTP server, but not try to
4900 load any image using TFTP
4902 autostart - if set to "yes", an image loaded using the "bootp",
4903 "rarpboot", "tftpboot" or "diskboot" commands will
4904 be automatically started (by internally calling
4907 If set to "no", a standalone image passed to the
4908 "bootm" command will be copied to the load address
4909 (and eventually uncompressed), but NOT be started.
4910 This can be used to load and uncompress arbitrary
4913 fdt_high - if set this restricts the maximum address that the
4914 flattened device tree will be copied into upon boot.
4915 For example, if you have a system with 1 GB memory
4916 at physical address 0x10000000, while Linux kernel
4917 only recognizes the first 704 MB as low memory, you
4918 may need to set fdt_high as 0x3C000000 to have the
4919 device tree blob be copied to the maximum address
4920 of the 704 MB low memory, so that Linux kernel can
4921 access it during the boot procedure.
4923 If this is set to the special value 0xFFFFFFFF then
4924 the fdt will not be copied at all on boot. For this
4925 to work it must reside in writable memory, have
4926 sufficient padding on the end of it for u-boot to
4927 add the information it needs into it, and the memory
4928 must be accessible by the kernel.
4930 fdtcontroladdr- if set this is the address of the control flattened
4931 device tree used by U-Boot when CONFIG_OF_CONTROL is
4934 i2cfast - (PPC405GP|PPC405EP only)
4935 if set to 'y' configures Linux I2C driver for fast
4936 mode (400kHZ). This environment variable is used in
4937 initialization code. So, for changes to be effective
4938 it must be saved and board must be reset.
4940 initrd_high - restrict positioning of initrd images:
4941 If this variable is not set, initrd images will be
4942 copied to the highest possible address in RAM; this
4943 is usually what you want since it allows for
4944 maximum initrd size. If for some reason you want to
4945 make sure that the initrd image is loaded below the
4946 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4947 variable to a value of "no" or "off" or "0".
4948 Alternatively, you can set it to a maximum upper
4949 address to use (U-Boot will still check that it
4950 does not overwrite the U-Boot stack and data).
4952 For instance, when you have a system with 16 MB
4953 RAM, and want to reserve 4 MB from use by Linux,
4954 you can do this by adding "mem=12M" to the value of
4955 the "bootargs" variable. However, now you must make
4956 sure that the initrd image is placed in the first
4957 12 MB as well - this can be done with
4959 setenv initrd_high 00c00000
4961 If you set initrd_high to 0xFFFFFFFF, this is an
4962 indication to U-Boot that all addresses are legal
4963 for the Linux kernel, including addresses in flash
4964 memory. In this case U-Boot will NOT COPY the
4965 ramdisk at all. This may be useful to reduce the
4966 boot time on your system, but requires that this
4967 feature is supported by your Linux kernel.
4969 ipaddr - IP address; needed for tftpboot command
4971 loadaddr - Default load address for commands like "bootp",
4972 "rarpboot", "tftpboot", "loadb" or "diskboot"
4974 loads_echo - see CONFIG_LOADS_ECHO
4976 serverip - TFTP server IP address; needed for tftpboot command
4978 bootretry - see CONFIG_BOOT_RETRY_TIME
4980 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4982 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4984 ethprime - controls which interface is used first.
4986 ethact - controls which interface is currently active.
4987 For example you can do the following
4989 => setenv ethact FEC
4990 => ping 192.168.0.1 # traffic sent on FEC
4991 => setenv ethact SCC
4992 => ping 10.0.0.1 # traffic sent on SCC
4994 ethrotate - When set to "no" U-Boot does not go through all
4995 available network interfaces.
4996 It just stays at the currently selected interface.
4998 netretry - When set to "no" each network operation will
4999 either succeed or fail without retrying.
5000 When set to "once" the network operation will
5001 fail when all the available network interfaces
5002 are tried once without success.
5003 Useful on scripts which control the retry operation
5006 npe_ucode - set load address for the NPE microcode
5008 silent_linux - If set then linux will be told to boot silently, by
5009 changing the console to be empty. If "yes" it will be
5010 made silent. If "no" it will not be made silent. If
5011 unset, then it will be made silent if the U-Boot console
5014 tftpsrcport - If this is set, the value is used for TFTP's
5017 tftpdstport - If this is set, the value is used for TFTP's UDP
5018 destination port instead of the Well Know Port 69.
5020 tftpblocksize - Block size to use for TFTP transfers; if not set,
5021 we use the TFTP server's default block size
5023 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5024 seconds, minimum value is 1000 = 1 second). Defines
5025 when a packet is considered to be lost so it has to
5026 be retransmitted. The default is 5000 = 5 seconds.
5027 Lowering this value may make downloads succeed
5028 faster in networks with high packet loss rates or
5029 with unreliable TFTP servers.
5031 vlan - When set to a value < 4095 the traffic over
5032 Ethernet is encapsulated/received over 802.1q
5035 The following image location variables contain the location of images
5036 used in booting. The "Image" column gives the role of the image and is
5037 not an environment variable name. The other columns are environment
5038 variable names. "File Name" gives the name of the file on a TFTP
5039 server, "RAM Address" gives the location in RAM the image will be
5040 loaded to, and "Flash Location" gives the image's address in NOR
5041 flash or offset in NAND flash.
5043 *Note* - these variables don't have to be defined for all boards, some
5044 boards currenlty use other variables for these purposes, and some
5045 boards use these variables for other purposes.
5047 Image File Name RAM Address Flash Location
5048 ----- --------- ----------- --------------
5049 u-boot u-boot u-boot_addr_r u-boot_addr
5050 Linux kernel bootfile kernel_addr_r kernel_addr
5051 device tree blob fdtfile fdt_addr_r fdt_addr
5052 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5054 The following environment variables may be used and automatically
5055 updated by the network boot commands ("bootp" and "rarpboot"),
5056 depending the information provided by your boot server:
5058 bootfile - see above
5059 dnsip - IP address of your Domain Name Server
5060 dnsip2 - IP address of your secondary Domain Name Server
5061 gatewayip - IP address of the Gateway (Router) to use
5062 hostname - Target hostname
5064 netmask - Subnet Mask
5065 rootpath - Pathname of the root filesystem on the NFS server
5066 serverip - see above
5069 There are two special Environment Variables:
5071 serial# - contains hardware identification information such
5072 as type string and/or serial number
5073 ethaddr - Ethernet address
5075 These variables can be set only once (usually during manufacturing of
5076 the board). U-Boot refuses to delete or overwrite these variables
5077 once they have been set once.
5080 Further special Environment Variables:
5082 ver - Contains the U-Boot version string as printed
5083 with the "version" command. This variable is
5084 readonly (see CONFIG_VERSION_VARIABLE).
5087 Please note that changes to some configuration parameters may take
5088 only effect after the next boot (yes, that's just like Windoze :-).
5091 Callback functions for environment variables:
5092 ---------------------------------------------
5094 For some environment variables, the behavior of u-boot needs to change
5095 when their values are changed. This functionailty allows functions to
5096 be associated with arbitrary variables. On creation, overwrite, or
5097 deletion, the callback will provide the opportunity for some side
5098 effect to happen or for the change to be rejected.
5100 The callbacks are named and associated with a function using the
5101 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5103 These callbacks are associated with variables in one of two ways. The
5104 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5105 in the board configuration to a string that defines a list of
5106 associations. The list must be in the following format:
5108 entry = variable_name[:callback_name]
5111 If the callback name is not specified, then the callback is deleted.
5112 Spaces are also allowed anywhere in the list.
5114 Callbacks can also be associated by defining the ".callbacks" variable
5115 with the same list format above. Any association in ".callbacks" will
5116 override any association in the static list. You can define
5117 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5118 ".callbacks" envirnoment variable in the default or embedded environment.
5121 Command Line Parsing:
5122 =====================
5124 There are two different command line parsers available with U-Boot:
5125 the old "simple" one, and the much more powerful "hush" shell:
5127 Old, simple command line parser:
5128 --------------------------------
5130 - supports environment variables (through setenv / saveenv commands)
5131 - several commands on one line, separated by ';'
5132 - variable substitution using "... ${name} ..." syntax
5133 - special characters ('$', ';') can be escaped by prefixing with '\',
5135 setenv bootcmd bootm \${address}
5136 - You can also escape text by enclosing in single apostrophes, for example:
5137 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5142 - similar to Bourne shell, with control structures like
5143 if...then...else...fi, for...do...done; while...do...done,
5144 until...do...done, ...
5145 - supports environment ("global") variables (through setenv / saveenv
5146 commands) and local shell variables (through standard shell syntax
5147 "name=value"); only environment variables can be used with "run"
5153 (1) If a command line (or an environment variable executed by a "run"
5154 command) contains several commands separated by semicolon, and
5155 one of these commands fails, then the remaining commands will be
5158 (2) If you execute several variables with one call to run (i. e.
5159 calling run with a list of variables as arguments), any failing
5160 command will cause "run" to terminate, i. e. the remaining
5161 variables are not executed.
5163 Note for Redundant Ethernet Interfaces:
5164 =======================================
5166 Some boards come with redundant Ethernet interfaces; U-Boot supports
5167 such configurations and is capable of automatic selection of a
5168 "working" interface when needed. MAC assignment works as follows:
5170 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5171 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5172 "eth1addr" (=>eth1), "eth2addr", ...
5174 If the network interface stores some valid MAC address (for instance
5175 in SROM), this is used as default address if there is NO correspon-
5176 ding setting in the environment; if the corresponding environment
5177 variable is set, this overrides the settings in the card; that means:
5179 o If the SROM has a valid MAC address, and there is no address in the
5180 environment, the SROM's address is used.
5182 o If there is no valid address in the SROM, and a definition in the
5183 environment exists, then the value from the environment variable is
5186 o If both the SROM and the environment contain a MAC address, and
5187 both addresses are the same, this MAC address is used.
5189 o If both the SROM and the environment contain a MAC address, and the
5190 addresses differ, the value from the environment is used and a
5193 o If neither SROM nor the environment contain a MAC address, an error
5196 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5197 will be programmed into hardware as part of the initialization process. This
5198 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5199 The naming convention is as follows:
5200 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5205 U-Boot is capable of booting (and performing other auxiliary operations on)
5206 images in two formats:
5208 New uImage format (FIT)
5209 -----------------------
5211 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5212 to Flattened Device Tree). It allows the use of images with multiple
5213 components (several kernels, ramdisks, etc.), with contents protected by
5214 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5220 Old image format is based on binary files which can be basically anything,
5221 preceded by a special header; see the definitions in include/image.h for
5222 details; basically, the header defines the following image properties:
5224 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5225 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5226 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5227 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5229 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5230 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5231 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5232 * Compression Type (uncompressed, gzip, bzip2)
5238 The header is marked by a special Magic Number, and both the header
5239 and the data portions of the image are secured against corruption by
5246 Although U-Boot should support any OS or standalone application
5247 easily, the main focus has always been on Linux during the design of
5250 U-Boot includes many features that so far have been part of some
5251 special "boot loader" code within the Linux kernel. Also, any
5252 "initrd" images to be used are no longer part of one big Linux image;
5253 instead, kernel and "initrd" are separate images. This implementation
5254 serves several purposes:
5256 - the same features can be used for other OS or standalone
5257 applications (for instance: using compressed images to reduce the
5258 Flash memory footprint)
5260 - it becomes much easier to port new Linux kernel versions because
5261 lots of low-level, hardware dependent stuff are done by U-Boot
5263 - the same Linux kernel image can now be used with different "initrd"
5264 images; of course this also means that different kernel images can
5265 be run with the same "initrd". This makes testing easier (you don't
5266 have to build a new "zImage.initrd" Linux image when you just
5267 change a file in your "initrd"). Also, a field-upgrade of the
5268 software is easier now.
5274 Porting Linux to U-Boot based systems:
5275 ---------------------------------------
5277 U-Boot cannot save you from doing all the necessary modifications to
5278 configure the Linux device drivers for use with your target hardware
5279 (no, we don't intend to provide a full virtual machine interface to
5282 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5284 Just make sure your machine specific header file (for instance
5285 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5286 Information structure as we define in include/asm-<arch>/u-boot.h,
5287 and make sure that your definition of IMAP_ADDR uses the same value
5288 as your U-Boot configuration in CONFIG_SYS_IMMR.
5291 Configuring the Linux kernel:
5292 -----------------------------
5294 No specific requirements for U-Boot. Make sure you have some root
5295 device (initial ramdisk, NFS) for your target system.
5298 Building a Linux Image:
5299 -----------------------
5301 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5302 not used. If you use recent kernel source, a new build target
5303 "uImage" will exist which automatically builds an image usable by
5304 U-Boot. Most older kernels also have support for a "pImage" target,
5305 which was introduced for our predecessor project PPCBoot and uses a
5306 100% compatible format.
5315 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5316 encapsulate a compressed Linux kernel image with header information,
5317 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5319 * build a standard "vmlinux" kernel image (in ELF binary format):
5321 * convert the kernel into a raw binary image:
5323 ${CROSS_COMPILE}-objcopy -O binary \
5324 -R .note -R .comment \
5325 -S vmlinux linux.bin
5327 * compress the binary image:
5331 * package compressed binary image for U-Boot:
5333 mkimage -A ppc -O linux -T kernel -C gzip \
5334 -a 0 -e 0 -n "Linux Kernel Image" \
5335 -d linux.bin.gz uImage
5338 The "mkimage" tool can also be used to create ramdisk images for use
5339 with U-Boot, either separated from the Linux kernel image, or
5340 combined into one file. "mkimage" encapsulates the images with a 64
5341 byte header containing information about target architecture,
5342 operating system, image type, compression method, entry points, time
5343 stamp, CRC32 checksums, etc.
5345 "mkimage" can be called in two ways: to verify existing images and
5346 print the header information, or to build new images.
5348 In the first form (with "-l" option) mkimage lists the information
5349 contained in the header of an existing U-Boot image; this includes
5350 checksum verification:
5352 tools/mkimage -l image
5353 -l ==> list image header information
5355 The second form (with "-d" option) is used to build a U-Boot image
5356 from a "data file" which is used as image payload:
5358 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5359 -n name -d data_file image
5360 -A ==> set architecture to 'arch'
5361 -O ==> set operating system to 'os'
5362 -T ==> set image type to 'type'
5363 -C ==> set compression type 'comp'
5364 -a ==> set load address to 'addr' (hex)
5365 -e ==> set entry point to 'ep' (hex)
5366 -n ==> set image name to 'name'
5367 -d ==> use image data from 'datafile'
5369 Right now, all Linux kernels for PowerPC systems use the same load
5370 address (0x00000000), but the entry point address depends on the
5373 - 2.2.x kernels have the entry point at 0x0000000C,
5374 - 2.3.x and later kernels have the entry point at 0x00000000.
5376 So a typical call to build a U-Boot image would read:
5378 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5379 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5380 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5381 > examples/uImage.TQM850L
5382 Image Name: 2.4.4 kernel for TQM850L
5383 Created: Wed Jul 19 02:34:59 2000
5384 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5385 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5386 Load Address: 0x00000000
5387 Entry Point: 0x00000000
5389 To verify the contents of the image (or check for corruption):
5391 -> tools/mkimage -l examples/uImage.TQM850L
5392 Image Name: 2.4.4 kernel for TQM850L
5393 Created: Wed Jul 19 02:34:59 2000
5394 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5395 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5396 Load Address: 0x00000000
5397 Entry Point: 0x00000000
5399 NOTE: for embedded systems where boot time is critical you can trade
5400 speed for memory and install an UNCOMPRESSED image instead: this
5401 needs more space in Flash, but boots much faster since it does not
5402 need to be uncompressed:
5404 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5405 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5406 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5407 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5408 > examples/uImage.TQM850L-uncompressed
5409 Image Name: 2.4.4 kernel for TQM850L
5410 Created: Wed Jul 19 02:34:59 2000
5411 Image Type: PowerPC Linux Kernel Image (uncompressed)
5412 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5413 Load Address: 0x00000000
5414 Entry Point: 0x00000000
5417 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5418 when your kernel is intended to use an initial ramdisk:
5420 -> tools/mkimage -n 'Simple Ramdisk Image' \
5421 > -A ppc -O linux -T ramdisk -C gzip \
5422 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5423 Image Name: Simple Ramdisk Image
5424 Created: Wed Jan 12 14:01:50 2000
5425 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5426 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5427 Load Address: 0x00000000
5428 Entry Point: 0x00000000
5430 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5431 option performs the converse operation of the mkimage's second form (the "-d"
5432 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5435 tools/dumpimage -i image -p position data_file
5436 -i ==> extract from the 'image' a specific 'data_file', \
5437 indexed by 'position'
5440 Installing a Linux Image:
5441 -------------------------
5443 To downloading a U-Boot image over the serial (console) interface,
5444 you must convert the image to S-Record format:
5446 objcopy -I binary -O srec examples/image examples/image.srec
5448 The 'objcopy' does not understand the information in the U-Boot
5449 image header, so the resulting S-Record file will be relative to
5450 address 0x00000000. To load it to a given address, you need to
5451 specify the target address as 'offset' parameter with the 'loads'
5454 Example: install the image to address 0x40100000 (which on the
5455 TQM8xxL is in the first Flash bank):
5457 => erase 40100000 401FFFFF
5463 ## Ready for S-Record download ...
5464 ~>examples/image.srec
5465 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5467 15989 15990 15991 15992
5468 [file transfer complete]
5470 ## Start Addr = 0x00000000
5473 You can check the success of the download using the 'iminfo' command;
5474 this includes a checksum verification so you can be sure no data
5475 corruption happened:
5479 ## Checking Image at 40100000 ...
5480 Image Name: 2.2.13 for initrd on TQM850L
5481 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5482 Data Size: 335725 Bytes = 327 kB = 0 MB
5483 Load Address: 00000000
5484 Entry Point: 0000000c
5485 Verifying Checksum ... OK
5491 The "bootm" command is used to boot an application that is stored in
5492 memory (RAM or Flash). In case of a Linux kernel image, the contents
5493 of the "bootargs" environment variable is passed to the kernel as
5494 parameters. You can check and modify this variable using the
5495 "printenv" and "setenv" commands:
5498 => printenv bootargs
5499 bootargs=root=/dev/ram
5501 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5503 => printenv bootargs
5504 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5507 ## Booting Linux kernel at 40020000 ...
5508 Image Name: 2.2.13 for NFS on TQM850L
5509 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5510 Data Size: 381681 Bytes = 372 kB = 0 MB
5511 Load Address: 00000000
5512 Entry Point: 0000000c
5513 Verifying Checksum ... OK
5514 Uncompressing Kernel Image ... OK
5515 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
5516 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5517 time_init: decrementer frequency = 187500000/60
5518 Calibrating delay loop... 49.77 BogoMIPS
5519 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5522 If you want to boot a Linux kernel with initial RAM disk, you pass
5523 the memory addresses of both the kernel and the initrd image (PPBCOOT
5524 format!) to the "bootm" command:
5526 => imi 40100000 40200000
5528 ## Checking Image at 40100000 ...
5529 Image Name: 2.2.13 for initrd on TQM850L
5530 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5531 Data Size: 335725 Bytes = 327 kB = 0 MB
5532 Load Address: 00000000
5533 Entry Point: 0000000c
5534 Verifying Checksum ... OK
5536 ## Checking Image at 40200000 ...
5537 Image Name: Simple Ramdisk Image
5538 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5539 Data Size: 566530 Bytes = 553 kB = 0 MB
5540 Load Address: 00000000
5541 Entry Point: 00000000
5542 Verifying Checksum ... OK
5544 => bootm 40100000 40200000
5545 ## Booting Linux kernel at 40100000 ...
5546 Image Name: 2.2.13 for initrd on TQM850L
5547 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5548 Data Size: 335725 Bytes = 327 kB = 0 MB
5549 Load Address: 00000000
5550 Entry Point: 0000000c
5551 Verifying Checksum ... OK
5552 Uncompressing Kernel Image ... OK
5553 ## Loading RAMDisk Image at 40200000 ...
5554 Image Name: Simple Ramdisk Image
5555 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5556 Data Size: 566530 Bytes = 553 kB = 0 MB
5557 Load Address: 00000000
5558 Entry Point: 00000000
5559 Verifying Checksum ... OK
5560 Loading Ramdisk ... OK
5561 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
5562 Boot arguments: root=/dev/ram
5563 time_init: decrementer frequency = 187500000/60
5564 Calibrating delay loop... 49.77 BogoMIPS
5566 RAMDISK: Compressed image found at block 0
5567 VFS: Mounted root (ext2 filesystem).
5571 Boot Linux and pass a flat device tree:
5574 First, U-Boot must be compiled with the appropriate defines. See the section
5575 titled "Linux Kernel Interface" above for a more in depth explanation. The
5576 following is an example of how to start a kernel and pass an updated
5582 oft=oftrees/mpc8540ads.dtb
5583 => tftp $oftaddr $oft
5584 Speed: 1000, full duplex
5586 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5587 Filename 'oftrees/mpc8540ads.dtb'.
5588 Load address: 0x300000
5591 Bytes transferred = 4106 (100a hex)
5592 => tftp $loadaddr $bootfile
5593 Speed: 1000, full duplex
5595 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5597 Load address: 0x200000
5598 Loading:############
5600 Bytes transferred = 1029407 (fb51f hex)
5605 => bootm $loadaddr - $oftaddr
5606 ## Booting image at 00200000 ...
5607 Image Name: Linux-2.6.17-dirty
5608 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5609 Data Size: 1029343 Bytes = 1005.2 kB
5610 Load Address: 00000000
5611 Entry Point: 00000000
5612 Verifying Checksum ... OK
5613 Uncompressing Kernel Image ... OK
5614 Booting using flat device tree at 0x300000
5615 Using MPC85xx ADS machine description
5616 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5620 More About U-Boot Image Types:
5621 ------------------------------
5623 U-Boot supports the following image types:
5625 "Standalone Programs" are directly runnable in the environment
5626 provided by U-Boot; it is expected that (if they behave
5627 well) you can continue to work in U-Boot after return from
5628 the Standalone Program.
5629 "OS Kernel Images" are usually images of some Embedded OS which
5630 will take over control completely. Usually these programs
5631 will install their own set of exception handlers, device
5632 drivers, set up the MMU, etc. - this means, that you cannot
5633 expect to re-enter U-Boot except by resetting the CPU.
5634 "RAMDisk Images" are more or less just data blocks, and their
5635 parameters (address, size) are passed to an OS kernel that is
5637 "Multi-File Images" contain several images, typically an OS
5638 (Linux) kernel image and one or more data images like
5639 RAMDisks. This construct is useful for instance when you want
5640 to boot over the network using BOOTP etc., where the boot
5641 server provides just a single image file, but you want to get
5642 for instance an OS kernel and a RAMDisk image.
5644 "Multi-File Images" start with a list of image sizes, each
5645 image size (in bytes) specified by an "uint32_t" in network
5646 byte order. This list is terminated by an "(uint32_t)0".
5647 Immediately after the terminating 0 follow the images, one by
5648 one, all aligned on "uint32_t" boundaries (size rounded up to
5649 a multiple of 4 bytes).
5651 "Firmware Images" are binary images containing firmware (like
5652 U-Boot or FPGA images) which usually will be programmed to
5655 "Script files" are command sequences that will be executed by
5656 U-Boot's command interpreter; this feature is especially
5657 useful when you configure U-Boot to use a real shell (hush)
5658 as command interpreter.
5660 Booting the Linux zImage:
5661 -------------------------
5663 On some platforms, it's possible to boot Linux zImage. This is done
5664 using the "bootz" command. The syntax of "bootz" command is the same
5665 as the syntax of "bootm" command.
5667 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5668 kernel with raw initrd images. The syntax is slightly different, the
5669 address of the initrd must be augmented by it's size, in the following
5670 format: "<initrd addres>:<initrd size>".
5676 One of the features of U-Boot is that you can dynamically load and
5677 run "standalone" applications, which can use some resources of
5678 U-Boot like console I/O functions or interrupt services.
5680 Two simple examples are included with the sources:
5685 'examples/hello_world.c' contains a small "Hello World" Demo
5686 application; it is automatically compiled when you build U-Boot.
5687 It's configured to run at address 0x00040004, so you can play with it
5691 ## Ready for S-Record download ...
5692 ~>examples/hello_world.srec
5693 1 2 3 4 5 6 7 8 9 10 11 ...
5694 [file transfer complete]
5696 ## Start Addr = 0x00040004
5698 => go 40004 Hello World! This is a test.
5699 ## Starting application at 0x00040004 ...
5710 Hit any key to exit ...
5712 ## Application terminated, rc = 0x0
5714 Another example, which demonstrates how to register a CPM interrupt
5715 handler with the U-Boot code, can be found in 'examples/timer.c'.
5716 Here, a CPM timer is set up to generate an interrupt every second.
5717 The interrupt service routine is trivial, just printing a '.'
5718 character, but this is just a demo program. The application can be
5719 controlled by the following keys:
5721 ? - print current values og the CPM Timer registers
5722 b - enable interrupts and start timer
5723 e - stop timer and disable interrupts
5724 q - quit application
5727 ## Ready for S-Record download ...
5728 ~>examples/timer.srec
5729 1 2 3 4 5 6 7 8 9 10 11 ...
5730 [file transfer complete]
5732 ## Start Addr = 0x00040004
5735 ## Starting application at 0x00040004 ...
5738 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5741 [q, b, e, ?] Set interval 1000000 us
5744 [q, b, e, ?] ........
5745 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5748 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5751 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5754 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5756 [q, b, e, ?] ...Stopping timer
5758 [q, b, e, ?] ## Application terminated, rc = 0x0
5764 Over time, many people have reported problems when trying to use the
5765 "minicom" terminal emulation program for serial download. I (wd)
5766 consider minicom to be broken, and recommend not to use it. Under
5767 Unix, I recommend to use C-Kermit for general purpose use (and
5768 especially for kermit binary protocol download ("loadb" command), and
5769 use "cu" for S-Record download ("loads" command). See
5770 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5771 for help with kermit.
5774 Nevertheless, if you absolutely want to use it try adding this
5775 configuration to your "File transfer protocols" section:
5777 Name Program Name U/D FullScr IO-Red. Multi
5778 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5779 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5785 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5786 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5788 Building requires a cross environment; it is known to work on
5789 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5790 need gmake since the Makefiles are not compatible with BSD make).
5791 Note that the cross-powerpc package does not install include files;
5792 attempting to build U-Boot will fail because <machine/ansi.h> is
5793 missing. This file has to be installed and patched manually:
5795 # cd /usr/pkg/cross/powerpc-netbsd/include
5797 # ln -s powerpc machine
5798 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5799 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5801 Native builds *don't* work due to incompatibilities between native
5802 and U-Boot include files.
5804 Booting assumes that (the first part of) the image booted is a
5805 stage-2 loader which in turn loads and then invokes the kernel
5806 proper. Loader sources will eventually appear in the NetBSD source
5807 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5808 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5811 Implementation Internals:
5812 =========================
5814 The following is not intended to be a complete description of every
5815 implementation detail. However, it should help to understand the
5816 inner workings of U-Boot and make it easier to port it to custom
5820 Initial Stack, Global Data:
5821 ---------------------------
5823 The implementation of U-Boot is complicated by the fact that U-Boot
5824 starts running out of ROM (flash memory), usually without access to
5825 system RAM (because the memory controller is not initialized yet).
5826 This means that we don't have writable Data or BSS segments, and BSS
5827 is not initialized as zero. To be able to get a C environment working
5828 at all, we have to allocate at least a minimal stack. Implementation
5829 options for this are defined and restricted by the CPU used: Some CPU
5830 models provide on-chip memory (like the IMMR area on MPC8xx and
5831 MPC826x processors), on others (parts of) the data cache can be
5832 locked as (mis-) used as memory, etc.
5834 Chris Hallinan posted a good summary of these issues to the
5835 U-Boot mailing list:
5837 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5838 From: "Chris Hallinan" <clh@net1plus.com>
5839 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5842 Correct me if I'm wrong, folks, but the way I understand it
5843 is this: Using DCACHE as initial RAM for Stack, etc, does not
5844 require any physical RAM backing up the cache. The cleverness
5845 is that the cache is being used as a temporary supply of
5846 necessary storage before the SDRAM controller is setup. It's
5847 beyond the scope of this list to explain the details, but you
5848 can see how this works by studying the cache architecture and
5849 operation in the architecture and processor-specific manuals.
5851 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5852 is another option for the system designer to use as an
5853 initial stack/RAM area prior to SDRAM being available. Either
5854 option should work for you. Using CS 4 should be fine if your
5855 board designers haven't used it for something that would
5856 cause you grief during the initial boot! It is frequently not
5859 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5860 with your processor/board/system design. The default value
5861 you will find in any recent u-boot distribution in
5862 walnut.h should work for you. I'd set it to a value larger
5863 than your SDRAM module. If you have a 64MB SDRAM module, set
5864 it above 400_0000. Just make sure your board has no resources
5865 that are supposed to respond to that address! That code in
5866 start.S has been around a while and should work as is when
5867 you get the config right.
5872 It is essential to remember this, since it has some impact on the C
5873 code for the initialization procedures:
5875 * Initialized global data (data segment) is read-only. Do not attempt
5878 * Do not use any uninitialized global data (or implicitely initialized
5879 as zero data - BSS segment) at all - this is undefined, initiali-
5880 zation is performed later (when relocating to RAM).
5882 * Stack space is very limited. Avoid big data buffers or things like
5885 Having only the stack as writable memory limits means we cannot use
5886 normal global data to share information beween the code. But it
5887 turned out that the implementation of U-Boot can be greatly
5888 simplified by making a global data structure (gd_t) available to all
5889 functions. We could pass a pointer to this data as argument to _all_
5890 functions, but this would bloat the code. Instead we use a feature of
5891 the GCC compiler (Global Register Variables) to share the data: we
5892 place a pointer (gd) to the global data into a register which we
5893 reserve for this purpose.
5895 When choosing a register for such a purpose we are restricted by the
5896 relevant (E)ABI specifications for the current architecture, and by
5897 GCC's implementation.
5899 For PowerPC, the following registers have specific use:
5901 R2: reserved for system use
5902 R3-R4: parameter passing and return values
5903 R5-R10: parameter passing
5904 R13: small data area pointer
5908 (U-Boot also uses R12 as internal GOT pointer. r12
5909 is a volatile register so r12 needs to be reset when
5910 going back and forth between asm and C)
5912 ==> U-Boot will use R2 to hold a pointer to the global data
5914 Note: on PPC, we could use a static initializer (since the
5915 address of the global data structure is known at compile time),
5916 but it turned out that reserving a register results in somewhat
5917 smaller code - although the code savings are not that big (on
5918 average for all boards 752 bytes for the whole U-Boot image,
5919 624 text + 127 data).
5921 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5922 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5924 ==> U-Boot will use P3 to hold a pointer to the global data
5926 On ARM, the following registers are used:
5928 R0: function argument word/integer result
5929 R1-R3: function argument word
5930 R9: platform specific
5931 R10: stack limit (used only if stack checking is enabled)
5932 R11: argument (frame) pointer
5933 R12: temporary workspace
5936 R15: program counter
5938 ==> U-Boot will use R9 to hold a pointer to the global data
5940 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5942 On Nios II, the ABI is documented here:
5943 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5945 ==> U-Boot will use gp to hold a pointer to the global data
5947 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5948 to access small data sections, so gp is free.
5950 On NDS32, the following registers are used:
5952 R0-R1: argument/return
5954 R15: temporary register for assembler
5955 R16: trampoline register
5956 R28: frame pointer (FP)
5957 R29: global pointer (GP)
5958 R30: link register (LP)
5959 R31: stack pointer (SP)
5960 PC: program counter (PC)
5962 ==> U-Boot will use R10 to hold a pointer to the global data
5964 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5965 or current versions of GCC may "optimize" the code too much.
5970 U-Boot runs in system state and uses physical addresses, i.e. the
5971 MMU is not used either for address mapping nor for memory protection.
5973 The available memory is mapped to fixed addresses using the memory
5974 controller. In this process, a contiguous block is formed for each
5975 memory type (Flash, SDRAM, SRAM), even when it consists of several
5976 physical memory banks.
5978 U-Boot is installed in the first 128 kB of the first Flash bank (on
5979 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5980 booting and sizing and initializing DRAM, the code relocates itself
5981 to the upper end of DRAM. Immediately below the U-Boot code some
5982 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5983 configuration setting]. Below that, a structure with global Board
5984 Info data is placed, followed by the stack (growing downward).
5986 Additionally, some exception handler code is copied to the low 8 kB
5987 of DRAM (0x00000000 ... 0x00001FFF).
5989 So a typical memory configuration with 16 MB of DRAM could look like
5992 0x0000 0000 Exception Vector code
5995 0x0000 2000 Free for Application Use
6001 0x00FB FF20 Monitor Stack (Growing downward)
6002 0x00FB FFAC Board Info Data and permanent copy of global data
6003 0x00FC 0000 Malloc Arena
6006 0x00FE 0000 RAM Copy of Monitor Code
6007 ... eventually: LCD or video framebuffer
6008 ... eventually: pRAM (Protected RAM - unchanged by reset)
6009 0x00FF FFFF [End of RAM]
6012 System Initialization:
6013 ----------------------
6015 In the reset configuration, U-Boot starts at the reset entry point
6016 (on most PowerPC systems at address 0x00000100). Because of the reset
6017 configuration for CS0# this is a mirror of the onboard Flash memory.
6018 To be able to re-map memory U-Boot then jumps to its link address.
6019 To be able to implement the initialization code in C, a (small!)
6020 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6021 which provide such a feature like MPC8xx or MPC8260), or in a locked
6022 part of the data cache. After that, U-Boot initializes the CPU core,
6023 the caches and the SIU.
6025 Next, all (potentially) available memory banks are mapped using a
6026 preliminary mapping. For example, we put them on 512 MB boundaries
6027 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6028 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6029 programmed for SDRAM access. Using the temporary configuration, a
6030 simple memory test is run that determines the size of the SDRAM
6033 When there is more than one SDRAM bank, and the banks are of
6034 different size, the largest is mapped first. For equal size, the first
6035 bank (CS2#) is mapped first. The first mapping is always for address
6036 0x00000000, with any additional banks following immediately to create
6037 contiguous memory starting from 0.
6039 Then, the monitor installs itself at the upper end of the SDRAM area
6040 and allocates memory for use by malloc() and for the global Board
6041 Info data; also, the exception vector code is copied to the low RAM
6042 pages, and the final stack is set up.
6044 Only after this relocation will you have a "normal" C environment;
6045 until that you are restricted in several ways, mostly because you are
6046 running from ROM, and because the code will have to be relocated to a
6050 U-Boot Porting Guide:
6051 ----------------------
6053 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6057 int main(int argc, char *argv[])
6059 sighandler_t no_more_time;
6061 signal(SIGALRM, no_more_time);
6062 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6064 if (available_money > available_manpower) {
6065 Pay consultant to port U-Boot;
6069 Download latest U-Boot source;
6071 Subscribe to u-boot mailing list;
6074 email("Hi, I am new to U-Boot, how do I get started?");
6077 Read the README file in the top level directory;
6078 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6079 Read applicable doc/*.README;
6080 Read the source, Luke;
6081 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6084 if (available_money > toLocalCurrency ($2500))
6087 Add a lot of aggravation and time;
6089 if (a similar board exists) { /* hopefully... */
6090 cp -a board/<similar> board/<myboard>
6091 cp include/configs/<similar>.h include/configs/<myboard>.h
6093 Create your own board support subdirectory;
6094 Create your own board include/configs/<myboard>.h file;
6096 Edit new board/<myboard> files
6097 Edit new include/configs/<myboard>.h
6102 Add / modify source code;
6106 email("Hi, I am having problems...");
6108 Send patch file to the U-Boot email list;
6109 if (reasonable critiques)
6110 Incorporate improvements from email list code review;
6112 Defend code as written;
6118 void no_more_time (int sig)
6127 All contributions to U-Boot should conform to the Linux kernel
6128 coding style; see the file "Documentation/CodingStyle" and the script
6129 "scripts/Lindent" in your Linux kernel source directory.
6131 Source files originating from a different project (for example the
6132 MTD subsystem) are generally exempt from these guidelines and are not
6133 reformated to ease subsequent migration to newer versions of those
6136 Please note that U-Boot is implemented in C (and to some small parts in
6137 Assembler); no C++ is used, so please do not use C++ style comments (//)
6140 Please also stick to the following formatting rules:
6141 - remove any trailing white space
6142 - use TAB characters for indentation and vertical alignment, not spaces
6143 - make sure NOT to use DOS '\r\n' line feeds
6144 - do not add more than 2 consecutive empty lines to source files
6145 - do not add trailing empty lines to source files
6147 Submissions which do not conform to the standards may be returned
6148 with a request to reformat the changes.
6154 Since the number of patches for U-Boot is growing, we need to
6155 establish some rules. Submissions which do not conform to these rules
6156 may be rejected, even when they contain important and valuable stuff.
6158 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6160 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6161 see http://lists.denx.de/mailman/listinfo/u-boot
6163 When you send a patch, please include the following information with
6166 * For bug fixes: a description of the bug and how your patch fixes
6167 this bug. Please try to include a way of demonstrating that the
6168 patch actually fixes something.
6170 * For new features: a description of the feature and your
6173 * A CHANGELOG entry as plaintext (separate from the patch)
6175 * For major contributions, your entry to the CREDITS file
6177 * When you add support for a new board, don't forget to add a
6178 maintainer e-mail address to the boards.cfg file, too.
6180 * If your patch adds new configuration options, don't forget to
6181 document these in the README file.
6183 * The patch itself. If you are using git (which is *strongly*
6184 recommended) you can easily generate the patch using the
6185 "git format-patch". If you then use "git send-email" to send it to
6186 the U-Boot mailing list, you will avoid most of the common problems
6187 with some other mail clients.
6189 If you cannot use git, use "diff -purN OLD NEW". If your version of
6190 diff does not support these options, then get the latest version of
6193 The current directory when running this command shall be the parent
6194 directory of the U-Boot source tree (i. e. please make sure that
6195 your patch includes sufficient directory information for the
6198 We prefer patches as plain text. MIME attachments are discouraged,
6199 and compressed attachments must not be used.
6201 * If one logical set of modifications affects or creates several
6202 files, all these changes shall be submitted in a SINGLE patch file.
6204 * Changesets that contain different, unrelated modifications shall be
6205 submitted as SEPARATE patches, one patch per changeset.
6210 * Before sending the patch, run the MAKEALL script on your patched
6211 source tree and make sure that no errors or warnings are reported
6212 for any of the boards.
6214 * Keep your modifications to the necessary minimum: A patch
6215 containing several unrelated changes or arbitrary reformats will be
6216 returned with a request to re-formatting / split it.
6218 * If you modify existing code, make sure that your new code does not
6219 add to the memory footprint of the code ;-) Small is beautiful!
6220 When adding new features, these should compile conditionally only
6221 (using #ifdef), and the resulting code with the new feature
6222 disabled must not need more memory than the old code without your
6225 * Remember that there is a size limit of 100 kB per message on the
6226 u-boot mailing list. Bigger patches will be moderated. If they are
6227 reasonable and not too big, they will be acknowledged. But patches
6228 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob