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_IOTRACE * I/O tracing for debugging
1004 CONFIG_CMD_IMPORTENV * import an environment
1005 CONFIG_CMD_INI * import data from an ini file into the env
1006 CONFIG_CMD_IRQ * irqinfo
1007 CONFIG_CMD_ITEST Integer/string test of 2 values
1008 CONFIG_CMD_JFFS2 * JFFS2 Support
1009 CONFIG_CMD_KGDB * kgdb
1010 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1011 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1013 CONFIG_CMD_LOADB loadb
1014 CONFIG_CMD_LOADS loads
1015 CONFIG_CMD_MD5SUM * print md5 message digest
1016 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1017 CONFIG_CMD_MEMINFO * Display detailed memory information
1018 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1020 CONFIG_CMD_MEMTEST * mtest
1021 CONFIG_CMD_MISC Misc functions like sleep etc
1022 CONFIG_CMD_MMC * MMC memory mapped support
1023 CONFIG_CMD_MII * MII utility commands
1024 CONFIG_CMD_MTDPARTS * MTD partition support
1025 CONFIG_CMD_NAND * NAND support
1026 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1027 CONFIG_CMD_NFS NFS support
1028 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1029 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1030 CONFIG_CMD_PCI * pciinfo
1031 CONFIG_CMD_PCMCIA * PCMCIA support
1032 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1034 CONFIG_CMD_PORTIO * Port I/O
1035 CONFIG_CMD_READ * Read raw data from partition
1036 CONFIG_CMD_REGINFO * Register dump
1037 CONFIG_CMD_RUN run command in env variable
1038 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1039 CONFIG_CMD_SAVES * save S record dump
1040 CONFIG_CMD_SCSI * SCSI Support
1041 CONFIG_CMD_SDRAM * print SDRAM configuration information
1042 (requires CONFIG_CMD_I2C)
1043 CONFIG_CMD_SETGETDCR Support for DCR Register access
1045 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1046 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1047 (requires CONFIG_CMD_MEMORY)
1048 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1049 CONFIG_CMD_SOURCE "source" command Support
1050 CONFIG_CMD_SPI * SPI serial bus support
1051 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1052 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1053 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1054 CONFIG_CMD_TIMER * access to the system tick timer
1055 CONFIG_CMD_USB * USB support
1056 CONFIG_CMD_CDP * Cisco Discover Protocol support
1057 CONFIG_CMD_MFSL * Microblaze FSL support
1058 CONFIG_CMD_XIMG Load part of Multi Image
1059 CONFIG_CMD_UUID * Generate random UUID or GUID string
1061 EXAMPLE: If you want all functions except of network
1062 support you can write:
1064 #include "config_cmd_all.h"
1065 #undef CONFIG_CMD_NET
1068 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1070 Note: Don't enable the "icache" and "dcache" commands
1071 (configuration option CONFIG_CMD_CACHE) unless you know
1072 what you (and your U-Boot users) are doing. Data
1073 cache cannot be enabled on systems like the 8xx or
1074 8260 (where accesses to the IMMR region must be
1075 uncached), and it cannot be disabled on all other
1076 systems where we (mis-) use the data cache to hold an
1077 initial stack and some data.
1080 XXX - this list needs to get updated!
1082 - Regular expression support:
1084 If this variable is defined, U-Boot is linked against
1085 the SLRE (Super Light Regular Expression) library,
1086 which adds regex support to some commands, as for
1087 example "env grep" and "setexpr".
1091 If this variable is defined, U-Boot will use a device tree
1092 to configure its devices, instead of relying on statically
1093 compiled #defines in the board file. This option is
1094 experimental and only available on a few boards. The device
1095 tree is available in the global data as gd->fdt_blob.
1097 U-Boot needs to get its device tree from somewhere. This can
1098 be done using one of the two options below:
1101 If this variable is defined, U-Boot will embed a device tree
1102 binary in its image. This device tree file should be in the
1103 board directory and called <soc>-<board>.dts. The binary file
1104 is then picked up in board_init_f() and made available through
1105 the global data structure as gd->blob.
1108 If this variable is defined, U-Boot will build a device tree
1109 binary. It will be called u-boot.dtb. Architecture-specific
1110 code will locate it at run-time. Generally this works by:
1112 cat u-boot.bin u-boot.dtb >image.bin
1114 and in fact, U-Boot does this for you, creating a file called
1115 u-boot-dtb.bin which is useful in the common case. You can
1116 still use the individual files if you need something more
1121 If this variable is defined, it enables watchdog
1122 support for the SoC. There must be support in the SoC
1123 specific code for a watchdog. For the 8xx and 8260
1124 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1125 register. When supported for a specific SoC is
1126 available, then no further board specific code should
1127 be needed to use it.
1130 When using a watchdog circuitry external to the used
1131 SoC, then define this variable and provide board
1132 specific code for the "hw_watchdog_reset" function.
1135 CONFIG_VERSION_VARIABLE
1136 If this variable is defined, an environment variable
1137 named "ver" is created by U-Boot showing the U-Boot
1138 version as printed by the "version" command.
1139 Any change to this variable will be reverted at the
1144 When CONFIG_CMD_DATE is selected, the type of the RTC
1145 has to be selected, too. Define exactly one of the
1148 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1149 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1150 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1151 CONFIG_RTC_MC146818 - use MC146818 RTC
1152 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1153 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1154 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1155 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1156 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1157 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1158 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1159 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1162 Note that if the RTC uses I2C, then the I2C interface
1163 must also be configured. See I2C Support, below.
1166 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1168 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1169 chip-ngpio pairs that tell the PCA953X driver the number of
1170 pins supported by a particular chip.
1172 Note that if the GPIO device uses I2C, then the I2C interface
1173 must also be configured. See I2C Support, below.
1176 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1177 accesses and can checksum them or write a list of them out
1178 to memory. See the 'iotrace' command for details. This is
1179 useful for testing device drivers since it can confirm that
1180 the driver behaves the same way before and after a code
1181 change. Currently this is supported on sandbox and arm. To
1182 add support for your architecture, add '#include <iotrace.h>'
1183 to the bottom of arch/<arch>/include/asm/io.h and test.
1185 Example output from the 'iotrace stats' command is below.
1186 Note that if the trace buffer is exhausted, the checksum will
1187 still continue to operate.
1190 Start: 10000000 (buffer start address)
1191 Size: 00010000 (buffer size)
1192 Offset: 00000120 (current buffer offset)
1193 Output: 10000120 (start + offset)
1194 Count: 00000018 (number of trace records)
1195 CRC32: 9526fb66 (CRC32 of all trace records)
1197 - Timestamp Support:
1199 When CONFIG_TIMESTAMP is selected, the timestamp
1200 (date and time) of an image is printed by image
1201 commands like bootm or iminfo. This option is
1202 automatically enabled when you select CONFIG_CMD_DATE .
1204 - Partition Labels (disklabels) Supported:
1205 Zero or more of the following:
1206 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1207 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1208 Intel architecture, USB sticks, etc.
1209 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1210 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1211 bootloader. Note 2TB partition limit; see
1213 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1215 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1216 CONFIG_CMD_SCSI) you must configure support for at
1217 least one non-MTD partition type as well.
1220 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1221 board configurations files but used nowhere!
1223 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1224 be performed by calling the function
1225 ide_set_reset(int reset)
1226 which has to be defined in a board specific file
1231 Set this to enable ATAPI support.
1236 Set this to enable support for disks larger than 137GB
1237 Also look at CONFIG_SYS_64BIT_LBA.
1238 Whithout these , LBA48 support uses 32bit variables and will 'only'
1239 support disks up to 2.1TB.
1241 CONFIG_SYS_64BIT_LBA:
1242 When enabled, makes the IDE subsystem use 64bit sector addresses.
1246 At the moment only there is only support for the
1247 SYM53C8XX SCSI controller; define
1248 CONFIG_SCSI_SYM53C8XX to enable it.
1250 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1251 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1252 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1253 maximum numbers of LUNs, SCSI ID's and target
1255 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1257 The environment variable 'scsidevs' is set to the number of
1258 SCSI devices found during the last scan.
1260 - NETWORK Support (PCI):
1262 Support for Intel 8254x/8257x gigabit chips.
1265 Utility code for direct access to the SPI bus on Intel 8257x.
1266 This does not do anything useful unless you set at least one
1267 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1269 CONFIG_E1000_SPI_GENERIC
1270 Allow generic access to the SPI bus on the Intel 8257x, for
1271 example with the "sspi" command.
1274 Management command for E1000 devices. When used on devices
1275 with SPI support you can reprogram the EEPROM from U-Boot.
1277 CONFIG_E1000_FALLBACK_MAC
1278 default MAC for empty EEPROM after production.
1281 Support for Intel 82557/82559/82559ER chips.
1282 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1283 write routine for first time initialisation.
1286 Support for Digital 2114x chips.
1287 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1288 modem chip initialisation (KS8761/QS6611).
1291 Support for National dp83815 chips.
1294 Support for National dp8382[01] gigabit chips.
1296 - NETWORK Support (other):
1298 CONFIG_DRIVER_AT91EMAC
1299 Support for AT91RM9200 EMAC.
1302 Define this to use reduced MII inteface
1304 CONFIG_DRIVER_AT91EMAC_QUIET
1305 If this defined, the driver is quiet.
1306 The driver doen't show link status messages.
1308 CONFIG_CALXEDA_XGMAC
1309 Support for the Calxeda XGMAC device
1312 Support for SMSC's LAN91C96 chips.
1314 CONFIG_LAN91C96_BASE
1315 Define this to hold the physical address
1316 of the LAN91C96's I/O space
1318 CONFIG_LAN91C96_USE_32_BIT
1319 Define this to enable 32 bit addressing
1322 Support for SMSC's LAN91C111 chip
1324 CONFIG_SMC91111_BASE
1325 Define this to hold the physical address
1326 of the device (I/O space)
1328 CONFIG_SMC_USE_32_BIT
1329 Define this if data bus is 32 bits
1331 CONFIG_SMC_USE_IOFUNCS
1332 Define this to use i/o functions instead of macros
1333 (some hardware wont work with macros)
1335 CONFIG_DRIVER_TI_EMAC
1336 Support for davinci emac
1338 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1339 Define this if you have more then 3 PHYs.
1342 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1344 CONFIG_FTGMAC100_EGIGA
1345 Define this to use GE link update with gigabit PHY.
1346 Define this if FTGMAC100 is connected to gigabit PHY.
1347 If your system has 10/100 PHY only, it might not occur
1348 wrong behavior. Because PHY usually return timeout or
1349 useless data when polling gigabit status and gigabit
1350 control registers. This behavior won't affect the
1351 correctnessof 10/100 link speed update.
1354 Support for SMSC's LAN911x and LAN921x chips
1357 Define this to hold the physical address
1358 of the device (I/O space)
1360 CONFIG_SMC911X_32_BIT
1361 Define this if data bus is 32 bits
1363 CONFIG_SMC911X_16_BIT
1364 Define this if data bus is 16 bits. If your processor
1365 automatically converts one 32 bit word to two 16 bit
1366 words you may also try CONFIG_SMC911X_32_BIT.
1369 Support for Renesas on-chip Ethernet controller
1371 CONFIG_SH_ETHER_USE_PORT
1372 Define the number of ports to be used
1374 CONFIG_SH_ETHER_PHY_ADDR
1375 Define the ETH PHY's address
1377 CONFIG_SH_ETHER_CACHE_WRITEBACK
1378 If this option is set, the driver enables cache flush.
1382 Support TPM devices.
1385 Support for i2c bus TPM devices. Only one device
1386 per system is supported at this time.
1388 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1389 Define the the i2c bus number for the TPM device
1391 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1392 Define the TPM's address on the i2c bus
1394 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1395 Define the burst count bytes upper limit
1397 CONFIG_TPM_ATMEL_TWI
1398 Support for Atmel TWI TPM device. Requires I2C support.
1401 Support for generic parallel port TPM devices. Only one device
1402 per system is supported at this time.
1404 CONFIG_TPM_TIS_BASE_ADDRESS
1405 Base address where the generic TPM device is mapped
1406 to. Contemporary x86 systems usually map it at
1410 Add tpm monitor functions.
1411 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1412 provides monitor access to authorized functions.
1415 Define this to enable the TPM support library which provides
1416 functional interfaces to some TPM commands.
1417 Requires support for a TPM device.
1419 CONFIG_TPM_AUTH_SESSIONS
1420 Define this to enable authorized functions in the TPM library.
1421 Requires CONFIG_TPM and CONFIG_SHA1.
1424 At the moment only the UHCI host controller is
1425 supported (PIP405, MIP405, MPC5200); define
1426 CONFIG_USB_UHCI to enable it.
1427 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1428 and define CONFIG_USB_STORAGE to enable the USB
1431 Supported are USB Keyboards and USB Floppy drives
1433 MPC5200 USB requires additional defines:
1435 for 528 MHz Clock: 0x0001bbbb
1439 for differential drivers: 0x00001000
1440 for single ended drivers: 0x00005000
1441 for differential drivers on PSC3: 0x00000100
1442 for single ended drivers on PSC3: 0x00004100
1443 CONFIG_SYS_USB_EVENT_POLL
1444 May be defined to allow interrupt polling
1445 instead of using asynchronous interrupts
1447 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1448 txfilltuning field in the EHCI controller on reset.
1451 Define the below if you wish to use the USB console.
1452 Once firmware is rebuilt from a serial console issue the
1453 command "setenv stdin usbtty; setenv stdout usbtty" and
1454 attach your USB cable. The Unix command "dmesg" should print
1455 it has found a new device. The environment variable usbtty
1456 can be set to gserial or cdc_acm to enable your device to
1457 appear to a USB host as a Linux gserial device or a
1458 Common Device Class Abstract Control Model serial device.
1459 If you select usbtty = gserial you should be able to enumerate
1461 # modprobe usbserial vendor=0xVendorID product=0xProductID
1462 else if using cdc_acm, simply setting the environment
1463 variable usbtty to be cdc_acm should suffice. The following
1464 might be defined in YourBoardName.h
1467 Define this to build a UDC device
1470 Define this to have a tty type of device available to
1471 talk to the UDC device
1474 Define this to enable the high speed support for usb
1475 device and usbtty. If this feature is enabled, a routine
1476 int is_usbd_high_speed(void)
1477 also needs to be defined by the driver to dynamically poll
1478 whether the enumeration has succeded at high speed or full
1481 CONFIG_SYS_CONSOLE_IS_IN_ENV
1482 Define this if you want stdin, stdout &/or stderr to
1486 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1487 Derive USB clock from external clock "blah"
1488 - CONFIG_SYS_USB_EXTC_CLK 0x02
1490 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1491 Derive USB clock from brgclk
1492 - CONFIG_SYS_USB_BRG_CLK 0x04
1494 If you have a USB-IF assigned VendorID then you may wish to
1495 define your own vendor specific values either in BoardName.h
1496 or directly in usbd_vendor_info.h. If you don't define
1497 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1498 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1499 should pretend to be a Linux device to it's target host.
1501 CONFIG_USBD_MANUFACTURER
1502 Define this string as the name of your company for
1503 - CONFIG_USBD_MANUFACTURER "my company"
1505 CONFIG_USBD_PRODUCT_NAME
1506 Define this string as the name of your product
1507 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1509 CONFIG_USBD_VENDORID
1510 Define this as your assigned Vendor ID from the USB
1511 Implementors Forum. This *must* be a genuine Vendor ID
1512 to avoid polluting the USB namespace.
1513 - CONFIG_USBD_VENDORID 0xFFFF
1515 CONFIG_USBD_PRODUCTID
1516 Define this as the unique Product ID
1518 - CONFIG_USBD_PRODUCTID 0xFFFF
1520 - ULPI Layer Support:
1521 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1522 the generic ULPI layer. The generic layer accesses the ULPI PHY
1523 via the platform viewport, so you need both the genric layer and
1524 the viewport enabled. Currently only Chipidea/ARC based
1525 viewport is supported.
1526 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1527 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1528 If your ULPI phy needs a different reference clock than the
1529 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1530 the appropriate value in Hz.
1533 The MMC controller on the Intel PXA is supported. To
1534 enable this define CONFIG_MMC. The MMC can be
1535 accessed from the boot prompt by mapping the device
1536 to physical memory similar to flash. Command line is
1537 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1538 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1541 Support for Renesas on-chip MMCIF controller
1543 CONFIG_SH_MMCIF_ADDR
1544 Define the base address of MMCIF registers
1547 Define the clock frequency for MMCIF
1550 Enable the generic MMC driver
1552 CONFIG_SUPPORT_EMMC_BOOT
1553 Enable some additional features of the eMMC boot partitions.
1555 CONFIG_SUPPORT_EMMC_RPMB
1556 Enable the commands for reading, writing and programming the
1557 key for the Replay Protection Memory Block partition in eMMC.
1559 - USB Device Firmware Update (DFU) class support:
1561 This enables the USB portion of the DFU USB class
1564 This enables the command "dfu" which is used to have
1565 U-Boot create a DFU class device via USB. This command
1566 requires that the "dfu_alt_info" environment variable be
1567 set and define the alt settings to expose to the host.
1570 This enables support for exposing (e)MMC devices via DFU.
1573 This enables support for exposing NAND devices via DFU.
1576 This enables support for exposing RAM via DFU.
1577 Note: DFU spec refer to non-volatile memory usage, but
1578 allow usages beyond the scope of spec - here RAM usage,
1579 one that would help mostly the developer.
1581 CONFIG_SYS_DFU_DATA_BUF_SIZE
1582 Dfu transfer uses a buffer before writing data to the
1583 raw storage device. Make the size (in bytes) of this buffer
1584 configurable. The size of this buffer is also configurable
1585 through the "dfu_bufsiz" environment variable.
1587 CONFIG_SYS_DFU_MAX_FILE_SIZE
1588 When updating files rather than the raw storage device,
1589 we use a static buffer to copy the file into and then write
1590 the buffer once we've been given the whole file. Define
1591 this to the maximum filesize (in bytes) for the buffer.
1592 Default is 4 MiB if undefined.
1594 DFU_DEFAULT_POLL_TIMEOUT
1595 Poll timeout [ms], is the timeout a device can send to the
1596 host. The host must wait for this timeout before sending
1597 a subsequent DFU_GET_STATUS request to the device.
1599 DFU_MANIFEST_POLL_TIMEOUT
1600 Poll timeout [ms], which the device sends to the host when
1601 entering dfuMANIFEST state. Host waits this timeout, before
1602 sending again an USB request to the device.
1604 - USB Device Android Fastboot support:
1606 This enables the command "fastboot" which enables the Android
1607 fastboot mode for the platform's USB device. Fastboot is a USB
1608 protocol for downloading images, flashing and device control
1609 used on Android devices.
1610 See doc/README.android-fastboot for more information.
1612 CONFIG_ANDROID_BOOT_IMAGE
1613 This enables support for booting images which use the Android
1614 image format header.
1616 CONFIG_USB_FASTBOOT_BUF_ADDR
1617 The fastboot protocol requires a large memory buffer for
1618 downloads. Define this to the starting RAM address to use for
1621 CONFIG_USB_FASTBOOT_BUF_SIZE
1622 The fastboot protocol requires a large memory buffer for
1623 downloads. This buffer should be as large as possible for a
1624 platform. Define this to the size available RAM for fastboot.
1626 - Journaling Flash filesystem support:
1627 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1628 CONFIG_JFFS2_NAND_DEV
1629 Define these for a default partition on a NAND device
1631 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1632 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1633 Define these for a default partition on a NOR device
1635 CONFIG_SYS_JFFS_CUSTOM_PART
1636 Define this to create an own partition. You have to provide a
1637 function struct part_info* jffs2_part_info(int part_num)
1639 If you define only one JFFS2 partition you may also want to
1640 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1641 to disable the command chpart. This is the default when you
1642 have not defined a custom partition
1644 - FAT(File Allocation Table) filesystem write function support:
1647 Define this to enable support for saving memory data as a
1648 file in FAT formatted partition.
1650 This will also enable the command "fatwrite" enabling the
1651 user to write files to FAT.
1653 CBFS (Coreboot Filesystem) support
1656 Define this to enable support for reading from a Coreboot
1657 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1660 - FAT(File Allocation Table) filesystem cluster size:
1661 CONFIG_FS_FAT_MAX_CLUSTSIZE
1663 Define the max cluster size for fat operations else
1664 a default value of 65536 will be defined.
1669 Define this to enable standard (PC-Style) keyboard
1673 Standard PC keyboard driver with US (is default) and
1674 GERMAN key layout (switch via environment 'keymap=de') support.
1675 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1676 for cfb_console. Supports cursor blinking.
1679 Enables a Chrome OS keyboard using the CROS_EC interface.
1680 This uses CROS_EC to communicate with a second microcontroller
1681 which provides key scans on request.
1686 Define this to enable video support (for output to
1689 CONFIG_VIDEO_CT69000
1691 Enable Chips & Technologies 69000 Video chip
1693 CONFIG_VIDEO_SMI_LYNXEM
1694 Enable Silicon Motion SMI 712/710/810 Video chip. The
1695 video output is selected via environment 'videoout'
1696 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1699 For the CT69000 and SMI_LYNXEM drivers, videomode is
1700 selected via environment 'videomode'. Two different ways
1702 - "videomode=num" 'num' is a standard LiLo mode numbers.
1703 Following standard modes are supported (* is default):
1705 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1706 -------------+---------------------------------------------
1707 8 bits | 0x301* 0x303 0x305 0x161 0x307
1708 15 bits | 0x310 0x313 0x316 0x162 0x319
1709 16 bits | 0x311 0x314 0x317 0x163 0x31A
1710 24 bits | 0x312 0x315 0x318 ? 0x31B
1711 -------------+---------------------------------------------
1712 (i.e. setenv videomode 317; saveenv; reset;)
1714 - "videomode=bootargs" all the video parameters are parsed
1715 from the bootargs. (See drivers/video/videomodes.c)
1718 CONFIG_VIDEO_SED13806
1719 Enable Epson SED13806 driver. This driver supports 8bpp
1720 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1721 or CONFIG_VIDEO_SED13806_16BPP
1724 Enable the Freescale DIU video driver. Reference boards for
1725 SOCs that have a DIU should define this macro to enable DIU
1726 support, and should also define these other macros:
1732 CONFIG_VIDEO_SW_CURSOR
1733 CONFIG_VGA_AS_SINGLE_DEVICE
1735 CONFIG_VIDEO_BMP_LOGO
1737 The DIU driver will look for the 'video-mode' environment
1738 variable, and if defined, enable the DIU as a console during
1739 boot. See the documentation file README.video for a
1740 description of this variable.
1744 Enable the VGA video / BIOS for x86. The alternative if you
1745 are using coreboot is to use the coreboot frame buffer
1752 Define this to enable a custom keyboard support.
1753 This simply calls drv_keyboard_init() which must be
1754 defined in your board-specific files.
1755 The only board using this so far is RBC823.
1757 - LCD Support: CONFIG_LCD
1759 Define this to enable LCD support (for output to LCD
1760 display); also select one of the supported displays
1761 by defining one of these:
1765 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1767 CONFIG_NEC_NL6448AC33:
1769 NEC NL6448AC33-18. Active, color, single scan.
1771 CONFIG_NEC_NL6448BC20
1773 NEC NL6448BC20-08. 6.5", 640x480.
1774 Active, color, single scan.
1776 CONFIG_NEC_NL6448BC33_54
1778 NEC NL6448BC33-54. 10.4", 640x480.
1779 Active, color, single scan.
1783 Sharp 320x240. Active, color, single scan.
1784 It isn't 16x9, and I am not sure what it is.
1786 CONFIG_SHARP_LQ64D341
1788 Sharp LQ64D341 display, 640x480.
1789 Active, color, single scan.
1793 HLD1045 display, 640x480.
1794 Active, color, single scan.
1798 Optrex CBL50840-2 NF-FW 99 22 M5
1800 Hitachi LMG6912RPFC-00T
1804 320x240. Black & white.
1806 Normally display is black on white background; define
1807 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1809 CONFIG_LCD_ALIGNMENT
1811 Normally the LCD is page-aligned (tyically 4KB). If this is
1812 defined then the LCD will be aligned to this value instead.
1813 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1814 here, since it is cheaper to change data cache settings on
1815 a per-section basis.
1817 CONFIG_CONSOLE_SCROLL_LINES
1819 When the console need to be scrolled, this is the number of
1820 lines to scroll by. It defaults to 1. Increasing this makes
1821 the console jump but can help speed up operation when scrolling
1826 Support drawing of RLE8-compressed bitmaps on the LCD.
1830 Enables an 'i2c edid' command which can read EDID
1831 information over I2C from an attached LCD display.
1833 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1835 If this option is set, the environment is checked for
1836 a variable "splashimage". If found, the usual display
1837 of logo, copyright and system information on the LCD
1838 is suppressed and the BMP image at the address
1839 specified in "splashimage" is loaded instead. The
1840 console is redirected to the "nulldev", too. This
1841 allows for a "silent" boot where a splash screen is
1842 loaded very quickly after power-on.
1844 CONFIG_SPLASHIMAGE_GUARD
1846 If this option is set, then U-Boot will prevent the environment
1847 variable "splashimage" from being set to a problematic address
1848 (see README.displaying-bmps).
1849 This option is useful for targets where, due to alignment
1850 restrictions, an improperly aligned BMP image will cause a data
1851 abort. If you think you will not have problems with unaligned
1852 accesses (for example because your toolchain prevents them)
1853 there is no need to set this option.
1855 CONFIG_SPLASH_SCREEN_ALIGN
1857 If this option is set the splash image can be freely positioned
1858 on the screen. Environment variable "splashpos" specifies the
1859 position as "x,y". If a positive number is given it is used as
1860 number of pixel from left/top. If a negative number is given it
1861 is used as number of pixel from right/bottom. You can also
1862 specify 'm' for centering the image.
1865 setenv splashpos m,m
1866 => image at center of screen
1868 setenv splashpos 30,20
1869 => image at x = 30 and y = 20
1871 setenv splashpos -10,m
1872 => vertically centered image
1873 at x = dspWidth - bmpWidth - 9
1875 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1877 If this option is set, additionally to standard BMP
1878 images, gzipped BMP images can be displayed via the
1879 splashscreen support or the bmp command.
1881 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1883 If this option is set, 8-bit RLE compressed BMP images
1884 can be displayed via the splashscreen support or the
1887 - Do compresssing for memory range:
1890 If this option is set, it would use zlib deflate method
1891 to compress the specified memory at its best effort.
1893 - Compression support:
1896 Enabled by default to support gzip compressed images.
1900 If this option is set, support for bzip2 compressed
1901 images is included. If not, only uncompressed and gzip
1902 compressed images are supported.
1904 NOTE: the bzip2 algorithm requires a lot of RAM, so
1905 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1910 If this option is set, support for lzma compressed
1913 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1914 requires an amount of dynamic memory that is given by the
1917 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1919 Where lc and lp stand for, respectively, Literal context bits
1920 and Literal pos bits.
1922 This value is upper-bounded by 14MB in the worst case. Anyway,
1923 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1924 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1925 a very small buffer.
1927 Use the lzmainfo tool to determinate the lc and lp values and
1928 then calculate the amount of needed dynamic memory (ensuring
1929 the appropriate CONFIG_SYS_MALLOC_LEN value).
1933 If this option is set, support for LZO compressed images
1939 The address of PHY on MII bus.
1941 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1943 The clock frequency of the MII bus
1947 If this option is set, support for speed/duplex
1948 detection of gigabit PHY is included.
1950 CONFIG_PHY_RESET_DELAY
1952 Some PHY like Intel LXT971A need extra delay after
1953 reset before any MII register access is possible.
1954 For such PHY, set this option to the usec delay
1955 required. (minimum 300usec for LXT971A)
1957 CONFIG_PHY_CMD_DELAY (ppc4xx)
1959 Some PHY like Intel LXT971A need extra delay after
1960 command issued before MII status register can be read
1970 Define a default value for Ethernet address to use
1971 for the respective Ethernet interface, in case this
1972 is not determined automatically.
1977 Define a default value for the IP address to use for
1978 the default Ethernet interface, in case this is not
1979 determined through e.g. bootp.
1980 (Environment variable "ipaddr")
1982 - Server IP address:
1985 Defines a default value for the IP address of a TFTP
1986 server to contact when using the "tftboot" command.
1987 (Environment variable "serverip")
1989 CONFIG_KEEP_SERVERADDR
1991 Keeps the server's MAC address, in the env 'serveraddr'
1992 for passing to bootargs (like Linux's netconsole option)
1994 - Gateway IP address:
1997 Defines a default value for the IP address of the
1998 default router where packets to other networks are
2000 (Environment variable "gatewayip")
2005 Defines a default value for the subnet mask (or
2006 routing prefix) which is used to determine if an IP
2007 address belongs to the local subnet or needs to be
2008 forwarded through a router.
2009 (Environment variable "netmask")
2011 - Multicast TFTP Mode:
2014 Defines whether you want to support multicast TFTP as per
2015 rfc-2090; for example to work with atftp. Lets lots of targets
2016 tftp down the same boot image concurrently. Note: the Ethernet
2017 driver in use must provide a function: mcast() to join/leave a
2020 - BOOTP Recovery Mode:
2021 CONFIG_BOOTP_RANDOM_DELAY
2023 If you have many targets in a network that try to
2024 boot using BOOTP, you may want to avoid that all
2025 systems send out BOOTP requests at precisely the same
2026 moment (which would happen for instance at recovery
2027 from a power failure, when all systems will try to
2028 boot, thus flooding the BOOTP server. Defining
2029 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2030 inserted before sending out BOOTP requests. The
2031 following delays are inserted then:
2033 1st BOOTP request: delay 0 ... 1 sec
2034 2nd BOOTP request: delay 0 ... 2 sec
2035 3rd BOOTP request: delay 0 ... 4 sec
2037 BOOTP requests: delay 0 ... 8 sec
2039 - DHCP Advanced Options:
2040 You can fine tune the DHCP functionality by defining
2041 CONFIG_BOOTP_* symbols:
2043 CONFIG_BOOTP_SUBNETMASK
2044 CONFIG_BOOTP_GATEWAY
2045 CONFIG_BOOTP_HOSTNAME
2046 CONFIG_BOOTP_NISDOMAIN
2047 CONFIG_BOOTP_BOOTPATH
2048 CONFIG_BOOTP_BOOTFILESIZE
2051 CONFIG_BOOTP_SEND_HOSTNAME
2052 CONFIG_BOOTP_NTPSERVER
2053 CONFIG_BOOTP_TIMEOFFSET
2054 CONFIG_BOOTP_VENDOREX
2055 CONFIG_BOOTP_MAY_FAIL
2057 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2058 environment variable, not the BOOTP server.
2060 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2061 after the configured retry count, the call will fail
2062 instead of starting over. This can be used to fail over
2063 to Link-local IP address configuration if the DHCP server
2066 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2067 serverip from a DHCP server, it is possible that more
2068 than one DNS serverip is offered to the client.
2069 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2070 serverip will be stored in the additional environment
2071 variable "dnsip2". The first DNS serverip is always
2072 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2075 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2076 to do a dynamic update of a DNS server. To do this, they
2077 need the hostname of the DHCP requester.
2078 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2079 of the "hostname" environment variable is passed as
2080 option 12 to the DHCP server.
2082 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2084 A 32bit value in microseconds for a delay between
2085 receiving a "DHCP Offer" and sending the "DHCP Request".
2086 This fixes a problem with certain DHCP servers that don't
2087 respond 100% of the time to a "DHCP request". E.g. On an
2088 AT91RM9200 processor running at 180MHz, this delay needed
2089 to be *at least* 15,000 usec before a Windows Server 2003
2090 DHCP server would reply 100% of the time. I recommend at
2091 least 50,000 usec to be safe. The alternative is to hope
2092 that one of the retries will be successful but note that
2093 the DHCP timeout and retry process takes a longer than
2096 - Link-local IP address negotiation:
2097 Negotiate with other link-local clients on the local network
2098 for an address that doesn't require explicit configuration.
2099 This is especially useful if a DHCP server cannot be guaranteed
2100 to exist in all environments that the device must operate.
2102 See doc/README.link-local for more information.
2105 CONFIG_CDP_DEVICE_ID
2107 The device id used in CDP trigger frames.
2109 CONFIG_CDP_DEVICE_ID_PREFIX
2111 A two character string which is prefixed to the MAC address
2116 A printf format string which contains the ascii name of
2117 the port. Normally is set to "eth%d" which sets
2118 eth0 for the first Ethernet, eth1 for the second etc.
2120 CONFIG_CDP_CAPABILITIES
2122 A 32bit integer which indicates the device capabilities;
2123 0x00000010 for a normal host which does not forwards.
2127 An ascii string containing the version of the software.
2131 An ascii string containing the name of the platform.
2135 A 32bit integer sent on the trigger.
2137 CONFIG_CDP_POWER_CONSUMPTION
2139 A 16bit integer containing the power consumption of the
2140 device in .1 of milliwatts.
2142 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2144 A byte containing the id of the VLAN.
2146 - Status LED: CONFIG_STATUS_LED
2148 Several configurations allow to display the current
2149 status using a LED. For instance, the LED will blink
2150 fast while running U-Boot code, stop blinking as
2151 soon as a reply to a BOOTP request was received, and
2152 start blinking slow once the Linux kernel is running
2153 (supported by a status LED driver in the Linux
2154 kernel). Defining CONFIG_STATUS_LED enables this
2160 The status LED can be connected to a GPIO pin.
2161 In such cases, the gpio_led driver can be used as a
2162 status LED backend implementation. Define CONFIG_GPIO_LED
2163 to include the gpio_led driver in the U-Boot binary.
2165 CONFIG_GPIO_LED_INVERTED_TABLE
2166 Some GPIO connected LEDs may have inverted polarity in which
2167 case the GPIO high value corresponds to LED off state and
2168 GPIO low value corresponds to LED on state.
2169 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2170 with a list of GPIO LEDs that have inverted polarity.
2172 - CAN Support: CONFIG_CAN_DRIVER
2174 Defining CONFIG_CAN_DRIVER enables CAN driver support
2175 on those systems that support this (optional)
2176 feature, like the TQM8xxL modules.
2178 - I2C Support: CONFIG_SYS_I2C
2180 This enable the NEW i2c subsystem, and will allow you to use
2181 i2c commands at the u-boot command line (as long as you set
2182 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2183 based realtime clock chips or other i2c devices. See
2184 common/cmd_i2c.c for a description of the command line
2187 ported i2c driver to the new framework:
2188 - drivers/i2c/soft_i2c.c:
2189 - activate first bus with CONFIG_SYS_I2C_SOFT define
2190 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2191 for defining speed and slave address
2192 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2193 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2194 for defining speed and slave address
2195 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2196 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2197 for defining speed and slave address
2198 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2199 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2200 for defining speed and slave address
2202 - drivers/i2c/fsl_i2c.c:
2203 - activate i2c driver with CONFIG_SYS_I2C_FSL
2204 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2205 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2206 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2208 - If your board supports a second fsl i2c bus, define
2209 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2210 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2211 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2214 - drivers/i2c/tegra_i2c.c:
2215 - activate this driver with CONFIG_SYS_I2C_TEGRA
2216 - This driver adds 4 i2c buses with a fix speed from
2217 100000 and the slave addr 0!
2219 - drivers/i2c/ppc4xx_i2c.c
2220 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2221 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2222 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2224 - drivers/i2c/i2c_mxc.c
2225 - activate this driver with CONFIG_SYS_I2C_MXC
2226 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2227 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2228 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2229 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2230 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2231 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2232 If thoses defines are not set, default value is 100000
2233 for speed, and 0 for slave.
2235 - drivers/i2c/rcar_i2c.c:
2236 - activate this driver with CONFIG_SYS_I2C_RCAR
2237 - This driver adds 4 i2c buses
2239 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2240 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2241 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2242 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2243 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2244 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2245 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2246 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2247 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2249 - drivers/i2c/sh_i2c.c:
2250 - activate this driver with CONFIG_SYS_I2C_SH
2251 - This driver adds from 2 to 5 i2c buses
2253 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2254 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2255 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2256 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2257 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2258 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2259 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2260 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2261 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2262 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2263 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2264 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2265 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2267 - drivers/i2c/omap24xx_i2c.c
2268 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2269 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2270 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2271 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2272 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2273 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2274 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2275 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2276 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2277 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2278 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2280 - drivers/i2c/zynq_i2c.c
2281 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2282 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2283 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2285 - drivers/i2c/s3c24x0_i2c.c:
2286 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2287 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2288 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2289 with a fix speed from 100000 and the slave addr 0!
2293 CONFIG_SYS_NUM_I2C_BUSES
2294 Hold the number of i2c busses you want to use. If you
2295 don't use/have i2c muxes on your i2c bus, this
2296 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2299 CONFIG_SYS_I2C_DIRECT_BUS
2300 define this, if you don't use i2c muxes on your hardware.
2301 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2304 CONFIG_SYS_I2C_MAX_HOPS
2305 define how many muxes are maximal consecutively connected
2306 on one i2c bus. If you not use i2c muxes, omit this
2309 CONFIG_SYS_I2C_BUSES
2310 hold a list of busses you want to use, only used if
2311 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2312 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2313 CONFIG_SYS_NUM_I2C_BUSES = 9:
2315 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2316 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2317 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2318 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2319 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2320 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2321 {1, {I2C_NULL_HOP}}, \
2322 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2323 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2327 bus 0 on adapter 0 without a mux
2328 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2329 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2330 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2331 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2332 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2333 bus 6 on adapter 1 without a mux
2334 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2335 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2337 If you do not have i2c muxes on your board, omit this define.
2339 - Legacy I2C Support: CONFIG_HARD_I2C
2341 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2342 provides the following compelling advantages:
2344 - more than one i2c adapter is usable
2345 - approved multibus support
2346 - better i2c mux support
2348 ** Please consider updating your I2C driver now. **
2350 These enable legacy I2C serial bus commands. Defining
2351 CONFIG_HARD_I2C will include the appropriate I2C driver
2352 for the selected CPU.
2354 This will allow you to use i2c commands at the u-boot
2355 command line (as long as you set CONFIG_CMD_I2C in
2356 CONFIG_COMMANDS) and communicate with i2c based realtime
2357 clock chips. See common/cmd_i2c.c for a description of the
2358 command line interface.
2360 CONFIG_HARD_I2C selects a hardware I2C controller.
2362 There are several other quantities that must also be
2363 defined when you define CONFIG_HARD_I2C.
2365 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2366 to be the frequency (in Hz) at which you wish your i2c bus
2367 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2368 the CPU's i2c node address).
2370 Now, the u-boot i2c code for the mpc8xx
2371 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2372 and so its address should therefore be cleared to 0 (See,
2373 eg, MPC823e User's Manual p.16-473). So, set
2374 CONFIG_SYS_I2C_SLAVE to 0.
2376 CONFIG_SYS_I2C_INIT_MPC5XXX
2378 When a board is reset during an i2c bus transfer
2379 chips might think that the current transfer is still
2380 in progress. Reset the slave devices by sending start
2381 commands until the slave device responds.
2383 That's all that's required for CONFIG_HARD_I2C.
2385 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2386 then the following macros need to be defined (examples are
2387 from include/configs/lwmon.h):
2391 (Optional). Any commands necessary to enable the I2C
2392 controller or configure ports.
2394 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2398 (Only for MPC8260 CPU). The I/O port to use (the code
2399 assumes both bits are on the same port). Valid values
2400 are 0..3 for ports A..D.
2404 The code necessary to make the I2C data line active
2405 (driven). If the data line is open collector, this
2408 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2412 The code necessary to make the I2C data line tri-stated
2413 (inactive). If the data line is open collector, this
2416 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2420 Code that returns true if the I2C data line is high,
2423 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2427 If <bit> is true, sets the I2C data line high. If it
2428 is false, it clears it (low).
2430 eg: #define I2C_SDA(bit) \
2431 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2432 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2436 If <bit> is true, sets the I2C clock line high. If it
2437 is false, it clears it (low).
2439 eg: #define I2C_SCL(bit) \
2440 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2441 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2445 This delay is invoked four times per clock cycle so this
2446 controls the rate of data transfer. The data rate thus
2447 is 1 / (I2C_DELAY * 4). Often defined to be something
2450 #define I2C_DELAY udelay(2)
2452 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2454 If your arch supports the generic GPIO framework (asm/gpio.h),
2455 then you may alternatively define the two GPIOs that are to be
2456 used as SCL / SDA. Any of the previous I2C_xxx macros will
2457 have GPIO-based defaults assigned to them as appropriate.
2459 You should define these to the GPIO value as given directly to
2460 the generic GPIO functions.
2462 CONFIG_SYS_I2C_INIT_BOARD
2464 When a board is reset during an i2c bus transfer
2465 chips might think that the current transfer is still
2466 in progress. On some boards it is possible to access
2467 the i2c SCLK line directly, either by using the
2468 processor pin as a GPIO or by having a second pin
2469 connected to the bus. If this option is defined a
2470 custom i2c_init_board() routine in boards/xxx/board.c
2471 is run early in the boot sequence.
2473 CONFIG_SYS_I2C_BOARD_LATE_INIT
2475 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2476 defined a custom i2c_board_late_init() routine in
2477 boards/xxx/board.c is run AFTER the operations in i2c_init()
2478 is completed. This callpoint can be used to unreset i2c bus
2479 using CPU i2c controller register accesses for CPUs whose i2c
2480 controller provide such a method. It is called at the end of
2481 i2c_init() to allow i2c_init operations to setup the i2c bus
2482 controller on the CPU (e.g. setting bus speed & slave address).
2484 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2486 This option enables configuration of bi_iic_fast[] flags
2487 in u-boot bd_info structure based on u-boot environment
2488 variable "i2cfast". (see also i2cfast)
2490 CONFIG_I2C_MULTI_BUS
2492 This option allows the use of multiple I2C buses, each of which
2493 must have a controller. At any point in time, only one bus is
2494 active. To switch to a different bus, use the 'i2c dev' command.
2495 Note that bus numbering is zero-based.
2497 CONFIG_SYS_I2C_NOPROBES
2499 This option specifies a list of I2C devices that will be skipped
2500 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2501 is set, specify a list of bus-device pairs. Otherwise, specify
2502 a 1D array of device addresses
2505 #undef CONFIG_I2C_MULTI_BUS
2506 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2508 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2510 #define CONFIG_I2C_MULTI_BUS
2511 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2513 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2515 CONFIG_SYS_SPD_BUS_NUM
2517 If defined, then this indicates the I2C bus number for DDR SPD.
2518 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2520 CONFIG_SYS_RTC_BUS_NUM
2522 If defined, then this indicates the I2C bus number for the RTC.
2523 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2525 CONFIG_SYS_DTT_BUS_NUM
2527 If defined, then this indicates the I2C bus number for the DTT.
2528 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2530 CONFIG_SYS_I2C_DTT_ADDR:
2532 If defined, specifies the I2C address of the DTT device.
2533 If not defined, then U-Boot uses predefined value for
2534 specified DTT device.
2536 CONFIG_SOFT_I2C_READ_REPEATED_START
2538 defining this will force the i2c_read() function in
2539 the soft_i2c driver to perform an I2C repeated start
2540 between writing the address pointer and reading the
2541 data. If this define is omitted the default behaviour
2542 of doing a stop-start sequence will be used. Most I2C
2543 devices can use either method, but some require one or
2546 - SPI Support: CONFIG_SPI
2548 Enables SPI driver (so far only tested with
2549 SPI EEPROM, also an instance works with Crystal A/D and
2550 D/As on the SACSng board)
2554 Enables the driver for SPI controller on SuperH. Currently
2555 only SH7757 is supported.
2559 Enables extended (16-bit) SPI EEPROM addressing.
2560 (symmetrical to CONFIG_I2C_X)
2564 Enables a software (bit-bang) SPI driver rather than
2565 using hardware support. This is a general purpose
2566 driver that only requires three general I/O port pins
2567 (two outputs, one input) to function. If this is
2568 defined, the board configuration must define several
2569 SPI configuration items (port pins to use, etc). For
2570 an example, see include/configs/sacsng.h.
2574 Enables a hardware SPI driver for general-purpose reads
2575 and writes. As with CONFIG_SOFT_SPI, the board configuration
2576 must define a list of chip-select function pointers.
2577 Currently supported on some MPC8xxx processors. For an
2578 example, see include/configs/mpc8349emds.h.
2582 Enables the driver for the SPI controllers on i.MX and MXC
2583 SoCs. Currently i.MX31/35/51 are supported.
2585 - FPGA Support: CONFIG_FPGA
2587 Enables FPGA subsystem.
2589 CONFIG_FPGA_<vendor>
2591 Enables support for specific chip vendors.
2594 CONFIG_FPGA_<family>
2596 Enables support for FPGA family.
2597 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2601 Specify the number of FPGA devices to support.
2603 CONFIG_CMD_FPGA_LOADMK
2605 Enable support for fpga loadmk command
2607 CONFIG_CMD_FPGA_LOADP
2609 Enable support for fpga loadp command - load partial bitstream
2611 CONFIG_CMD_FPGA_LOADBP
2613 Enable support for fpga loadbp command - load partial bitstream
2616 CONFIG_SYS_FPGA_PROG_FEEDBACK
2618 Enable printing of hash marks during FPGA configuration.
2620 CONFIG_SYS_FPGA_CHECK_BUSY
2622 Enable checks on FPGA configuration interface busy
2623 status by the configuration function. This option
2624 will require a board or device specific function to
2629 If defined, a function that provides delays in the FPGA
2630 configuration driver.
2632 CONFIG_SYS_FPGA_CHECK_CTRLC
2633 Allow Control-C to interrupt FPGA configuration
2635 CONFIG_SYS_FPGA_CHECK_ERROR
2637 Check for configuration errors during FPGA bitfile
2638 loading. For example, abort during Virtex II
2639 configuration if the INIT_B line goes low (which
2640 indicated a CRC error).
2642 CONFIG_SYS_FPGA_WAIT_INIT
2644 Maximum time to wait for the INIT_B line to deassert
2645 after PROB_B has been deasserted during a Virtex II
2646 FPGA configuration sequence. The default time is 500
2649 CONFIG_SYS_FPGA_WAIT_BUSY
2651 Maximum time to wait for BUSY to deassert during
2652 Virtex II FPGA configuration. The default is 5 ms.
2654 CONFIG_SYS_FPGA_WAIT_CONFIG
2656 Time to wait after FPGA configuration. The default is
2659 - Configuration Management:
2662 If defined, this string will be added to the U-Boot
2663 version information (U_BOOT_VERSION)
2665 - Vendor Parameter Protection:
2667 U-Boot considers the values of the environment
2668 variables "serial#" (Board Serial Number) and
2669 "ethaddr" (Ethernet Address) to be parameters that
2670 are set once by the board vendor / manufacturer, and
2671 protects these variables from casual modification by
2672 the user. Once set, these variables are read-only,
2673 and write or delete attempts are rejected. You can
2674 change this behaviour:
2676 If CONFIG_ENV_OVERWRITE is #defined in your config
2677 file, the write protection for vendor parameters is
2678 completely disabled. Anybody can change or delete
2681 Alternatively, if you #define _both_ CONFIG_ETHADDR
2682 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2683 Ethernet address is installed in the environment,
2684 which can be changed exactly ONCE by the user. [The
2685 serial# is unaffected by this, i. e. it remains
2688 The same can be accomplished in a more flexible way
2689 for any variable by configuring the type of access
2690 to allow for those variables in the ".flags" variable
2691 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2696 Define this variable to enable the reservation of
2697 "protected RAM", i. e. RAM which is not overwritten
2698 by U-Boot. Define CONFIG_PRAM to hold the number of
2699 kB you want to reserve for pRAM. You can overwrite
2700 this default value by defining an environment
2701 variable "pram" to the number of kB you want to
2702 reserve. Note that the board info structure will
2703 still show the full amount of RAM. If pRAM is
2704 reserved, a new environment variable "mem" will
2705 automatically be defined to hold the amount of
2706 remaining RAM in a form that can be passed as boot
2707 argument to Linux, for instance like that:
2709 setenv bootargs ... mem=\${mem}
2712 This way you can tell Linux not to use this memory,
2713 either, which results in a memory region that will
2714 not be affected by reboots.
2716 *WARNING* If your board configuration uses automatic
2717 detection of the RAM size, you must make sure that
2718 this memory test is non-destructive. So far, the
2719 following board configurations are known to be
2722 IVMS8, IVML24, SPD8xx, TQM8xxL,
2723 HERMES, IP860, RPXlite, LWMON,
2726 - Access to physical memory region (> 4GB)
2727 Some basic support is provided for operations on memory not
2728 normally accessible to U-Boot - e.g. some architectures
2729 support access to more than 4GB of memory on 32-bit
2730 machines using physical address extension or similar.
2731 Define CONFIG_PHYSMEM to access this basic support, which
2732 currently only supports clearing the memory.
2737 Define this variable to stop the system in case of a
2738 fatal error, so that you have to reset it manually.
2739 This is probably NOT a good idea for an embedded
2740 system where you want the system to reboot
2741 automatically as fast as possible, but it may be
2742 useful during development since you can try to debug
2743 the conditions that lead to the situation.
2745 CONFIG_NET_RETRY_COUNT
2747 This variable defines the number of retries for
2748 network operations like ARP, RARP, TFTP, or BOOTP
2749 before giving up the operation. If not defined, a
2750 default value of 5 is used.
2754 Timeout waiting for an ARP reply in milliseconds.
2758 Timeout in milliseconds used in NFS protocol.
2759 If you encounter "ERROR: Cannot umount" in nfs command,
2760 try longer timeout such as
2761 #define CONFIG_NFS_TIMEOUT 10000UL
2763 - Command Interpreter:
2764 CONFIG_AUTO_COMPLETE
2766 Enable auto completion of commands using TAB.
2768 Note that this feature has NOT been implemented yet
2769 for the "hush" shell.
2772 CONFIG_SYS_HUSH_PARSER
2774 Define this variable to enable the "hush" shell (from
2775 Busybox) as command line interpreter, thus enabling
2776 powerful command line syntax like
2777 if...then...else...fi conditionals or `&&' and '||'
2778 constructs ("shell scripts").
2780 If undefined, you get the old, much simpler behaviour
2781 with a somewhat smaller memory footprint.
2784 CONFIG_SYS_PROMPT_HUSH_PS2
2786 This defines the secondary prompt string, which is
2787 printed when the command interpreter needs more input
2788 to complete a command. Usually "> ".
2792 In the current implementation, the local variables
2793 space and global environment variables space are
2794 separated. Local variables are those you define by
2795 simply typing `name=value'. To access a local
2796 variable later on, you have write `$name' or
2797 `${name}'; to execute the contents of a variable
2798 directly type `$name' at the command prompt.
2800 Global environment variables are those you use
2801 setenv/printenv to work with. To run a command stored
2802 in such a variable, you need to use the run command,
2803 and you must not use the '$' sign to access them.
2805 To store commands and special characters in a
2806 variable, please use double quotation marks
2807 surrounding the whole text of the variable, instead
2808 of the backslashes before semicolons and special
2811 - Commandline Editing and History:
2812 CONFIG_CMDLINE_EDITING
2814 Enable editing and History functions for interactive
2815 commandline input operations
2817 - Default Environment:
2818 CONFIG_EXTRA_ENV_SETTINGS
2820 Define this to contain any number of null terminated
2821 strings (variable = value pairs) that will be part of
2822 the default environment compiled into the boot image.
2824 For example, place something like this in your
2825 board's config file:
2827 #define CONFIG_EXTRA_ENV_SETTINGS \
2831 Warning: This method is based on knowledge about the
2832 internal format how the environment is stored by the
2833 U-Boot code. This is NOT an official, exported
2834 interface! Although it is unlikely that this format
2835 will change soon, there is no guarantee either.
2836 You better know what you are doing here.
2838 Note: overly (ab)use of the default environment is
2839 discouraged. Make sure to check other ways to preset
2840 the environment like the "source" command or the
2843 CONFIG_ENV_VARS_UBOOT_CONFIG
2845 Define this in order to add variables describing the
2846 U-Boot build configuration to the default environment.
2847 These will be named arch, cpu, board, vendor, and soc.
2849 Enabling this option will cause the following to be defined:
2857 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2859 Define this in order to add variables describing certain
2860 run-time determined information about the hardware to the
2861 environment. These will be named board_name, board_rev.
2863 CONFIG_DELAY_ENVIRONMENT
2865 Normally the environment is loaded when the board is
2866 intialised so that it is available to U-Boot. This inhibits
2867 that so that the environment is not available until
2868 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2869 this is instead controlled by the value of
2870 /config/load-environment.
2872 - DataFlash Support:
2873 CONFIG_HAS_DATAFLASH
2875 Defining this option enables DataFlash features and
2876 allows to read/write in Dataflash via the standard
2879 - Serial Flash support
2882 Defining this option enables SPI flash commands
2883 'sf probe/read/write/erase/update'.
2885 Usage requires an initial 'probe' to define the serial
2886 flash parameters, followed by read/write/erase/update
2889 The following defaults may be provided by the platform
2890 to handle the common case when only a single serial
2891 flash is present on the system.
2893 CONFIG_SF_DEFAULT_BUS Bus identifier
2894 CONFIG_SF_DEFAULT_CS Chip-select
2895 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2896 CONFIG_SF_DEFAULT_SPEED in Hz
2900 Define this option to include a destructive SPI flash
2903 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2905 Define this option to use the Bank addr/Extended addr
2906 support on SPI flashes which has size > 16Mbytes.
2908 CONFIG_SF_DUAL_FLASH Dual flash memories
2910 Define this option to use dual flash support where two flash
2911 memories can be connected with a given cs line.
2912 currently Xilinx Zynq qspi support these type of connections.
2914 - SystemACE Support:
2917 Adding this option adds support for Xilinx SystemACE
2918 chips attached via some sort of local bus. The address
2919 of the chip must also be defined in the
2920 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2922 #define CONFIG_SYSTEMACE
2923 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2925 When SystemACE support is added, the "ace" device type
2926 becomes available to the fat commands, i.e. fatls.
2928 - TFTP Fixed UDP Port:
2931 If this is defined, the environment variable tftpsrcp
2932 is used to supply the TFTP UDP source port value.
2933 If tftpsrcp isn't defined, the normal pseudo-random port
2934 number generator is used.
2936 Also, the environment variable tftpdstp is used to supply
2937 the TFTP UDP destination port value. If tftpdstp isn't
2938 defined, the normal port 69 is used.
2940 The purpose for tftpsrcp is to allow a TFTP server to
2941 blindly start the TFTP transfer using the pre-configured
2942 target IP address and UDP port. This has the effect of
2943 "punching through" the (Windows XP) firewall, allowing
2944 the remainder of the TFTP transfer to proceed normally.
2945 A better solution is to properly configure the firewall,
2946 but sometimes that is not allowed.
2951 This enables a generic 'hash' command which can produce
2952 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2956 Enable the hash verify command (hash -v). This adds to code
2959 CONFIG_SHA1 - support SHA1 hashing
2960 CONFIG_SHA256 - support SHA256 hashing
2962 Note: There is also a sha1sum command, which should perhaps
2963 be deprecated in favour of 'hash sha1'.
2965 - Freescale i.MX specific commands:
2966 CONFIG_CMD_HDMIDETECT
2967 This enables 'hdmidet' command which returns true if an
2968 HDMI monitor is detected. This command is i.MX 6 specific.
2971 This enables the 'bmode' (bootmode) command for forcing
2972 a boot from specific media.
2974 This is useful for forcing the ROM's usb downloader to
2975 activate upon a watchdog reset which is nice when iterating
2976 on U-Boot. Using the reset button or running bmode normal
2977 will set it back to normal. This command currently
2978 supports i.MX53 and i.MX6.
2983 This enables the RSA algorithm used for FIT image verification
2984 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2986 The signing part is build into mkimage regardless of this
2989 - bootcount support:
2990 CONFIG_BOOTCOUNT_LIMIT
2992 This enables the bootcounter support, see:
2993 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2996 enable special bootcounter support on at91sam9xe based boards.
2998 enable special bootcounter support on blackfin based boards.
3000 enable special bootcounter support on da850 based boards.
3001 CONFIG_BOOTCOUNT_RAM
3002 enable support for the bootcounter in RAM
3003 CONFIG_BOOTCOUNT_I2C
3004 enable support for the bootcounter on an i2c (like RTC) device.
3005 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3006 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3008 CONFIG_BOOTCOUNT_ALEN = address len
3010 - Show boot progress:
3011 CONFIG_SHOW_BOOT_PROGRESS
3013 Defining this option allows to add some board-
3014 specific code (calling a user-provided function
3015 "show_boot_progress(int)") that enables you to show
3016 the system's boot progress on some display (for
3017 example, some LED's) on your board. At the moment,
3018 the following checkpoints are implemented:
3020 - Detailed boot stage timing
3022 Define this option to get detailed timing of each stage
3023 of the boot process.
3025 CONFIG_BOOTSTAGE_USER_COUNT
3026 This is the number of available user bootstage records.
3027 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3028 a new ID will be allocated from this stash. If you exceed
3029 the limit, recording will stop.
3031 CONFIG_BOOTSTAGE_REPORT
3032 Define this to print a report before boot, similar to this:
3034 Timer summary in microseconds:
3037 3,575,678 3,575,678 board_init_f start
3038 3,575,695 17 arch_cpu_init A9
3039 3,575,777 82 arch_cpu_init done
3040 3,659,598 83,821 board_init_r start
3041 3,910,375 250,777 main_loop
3042 29,916,167 26,005,792 bootm_start
3043 30,361,327 445,160 start_kernel
3045 CONFIG_CMD_BOOTSTAGE
3046 Add a 'bootstage' command which supports printing a report
3047 and un/stashing of bootstage data.
3049 CONFIG_BOOTSTAGE_FDT
3050 Stash the bootstage information in the FDT. A root 'bootstage'
3051 node is created with each bootstage id as a child. Each child
3052 has a 'name' property and either 'mark' containing the
3053 mark time in microsecond, or 'accum' containing the
3054 accumulated time for that bootstage id in microseconds.
3059 name = "board_init_f";
3068 Code in the Linux kernel can find this in /proc/devicetree.
3070 Legacy uImage format:
3073 1 common/cmd_bootm.c before attempting to boot an image
3074 -1 common/cmd_bootm.c Image header has bad magic number
3075 2 common/cmd_bootm.c Image header has correct magic number
3076 -2 common/cmd_bootm.c Image header has bad checksum
3077 3 common/cmd_bootm.c Image header has correct checksum
3078 -3 common/cmd_bootm.c Image data has bad checksum
3079 4 common/cmd_bootm.c Image data has correct checksum
3080 -4 common/cmd_bootm.c Image is for unsupported architecture
3081 5 common/cmd_bootm.c Architecture check OK
3082 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3083 6 common/cmd_bootm.c Image Type check OK
3084 -6 common/cmd_bootm.c gunzip uncompression error
3085 -7 common/cmd_bootm.c Unimplemented compression type
3086 7 common/cmd_bootm.c Uncompression OK
3087 8 common/cmd_bootm.c No uncompress/copy overwrite error
3088 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3090 9 common/image.c Start initial ramdisk verification
3091 -10 common/image.c Ramdisk header has bad magic number
3092 -11 common/image.c Ramdisk header has bad checksum
3093 10 common/image.c Ramdisk header is OK
3094 -12 common/image.c Ramdisk data has bad checksum
3095 11 common/image.c Ramdisk data has correct checksum
3096 12 common/image.c Ramdisk verification complete, start loading
3097 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3098 13 common/image.c Start multifile image verification
3099 14 common/image.c No initial ramdisk, no multifile, continue.
3101 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3103 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3104 -31 post/post.c POST test failed, detected by post_output_backlog()
3105 -32 post/post.c POST test failed, detected by post_run_single()
3107 34 common/cmd_doc.c before loading a Image from a DOC device
3108 -35 common/cmd_doc.c Bad usage of "doc" command
3109 35 common/cmd_doc.c correct usage of "doc" command
3110 -36 common/cmd_doc.c No boot device
3111 36 common/cmd_doc.c correct boot device
3112 -37 common/cmd_doc.c Unknown Chip ID on boot device
3113 37 common/cmd_doc.c correct chip ID found, device available
3114 -38 common/cmd_doc.c Read Error on boot device
3115 38 common/cmd_doc.c reading Image header from DOC device OK
3116 -39 common/cmd_doc.c Image header has bad magic number
3117 39 common/cmd_doc.c Image header has correct magic number
3118 -40 common/cmd_doc.c Error reading Image from DOC device
3119 40 common/cmd_doc.c Image header has correct magic number
3120 41 common/cmd_ide.c before loading a Image from a IDE device
3121 -42 common/cmd_ide.c Bad usage of "ide" command
3122 42 common/cmd_ide.c correct usage of "ide" command
3123 -43 common/cmd_ide.c No boot device
3124 43 common/cmd_ide.c boot device found
3125 -44 common/cmd_ide.c Device not available
3126 44 common/cmd_ide.c Device available
3127 -45 common/cmd_ide.c wrong partition selected
3128 45 common/cmd_ide.c partition selected
3129 -46 common/cmd_ide.c Unknown partition table
3130 46 common/cmd_ide.c valid partition table found
3131 -47 common/cmd_ide.c Invalid partition type
3132 47 common/cmd_ide.c correct partition type
3133 -48 common/cmd_ide.c Error reading Image Header on boot device
3134 48 common/cmd_ide.c reading Image Header from IDE device OK
3135 -49 common/cmd_ide.c Image header has bad magic number
3136 49 common/cmd_ide.c Image header has correct magic number
3137 -50 common/cmd_ide.c Image header has bad checksum
3138 50 common/cmd_ide.c Image header has correct checksum
3139 -51 common/cmd_ide.c Error reading Image from IDE device
3140 51 common/cmd_ide.c reading Image from IDE device OK
3141 52 common/cmd_nand.c before loading a Image from a NAND device
3142 -53 common/cmd_nand.c Bad usage of "nand" command
3143 53 common/cmd_nand.c correct usage of "nand" command
3144 -54 common/cmd_nand.c No boot device
3145 54 common/cmd_nand.c boot device found
3146 -55 common/cmd_nand.c Unknown Chip ID on boot device
3147 55 common/cmd_nand.c correct chip ID found, device available
3148 -56 common/cmd_nand.c Error reading Image Header on boot device
3149 56 common/cmd_nand.c reading Image Header from NAND device OK
3150 -57 common/cmd_nand.c Image header has bad magic number
3151 57 common/cmd_nand.c Image header has correct magic number
3152 -58 common/cmd_nand.c Error reading Image from NAND device
3153 58 common/cmd_nand.c reading Image from NAND device OK
3155 -60 common/env_common.c Environment has a bad CRC, using default
3157 64 net/eth.c starting with Ethernet configuration.
3158 -64 net/eth.c no Ethernet found.
3159 65 net/eth.c Ethernet found.
3161 -80 common/cmd_net.c usage wrong
3162 80 common/cmd_net.c before calling NetLoop()
3163 -81 common/cmd_net.c some error in NetLoop() occurred
3164 81 common/cmd_net.c NetLoop() back without error
3165 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3166 82 common/cmd_net.c trying automatic boot
3167 83 common/cmd_net.c running "source" command
3168 -83 common/cmd_net.c some error in automatic boot or "source" command
3169 84 common/cmd_net.c end without errors
3174 100 common/cmd_bootm.c Kernel FIT Image has correct format
3175 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3176 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3177 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3178 102 common/cmd_bootm.c Kernel unit name specified
3179 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3180 103 common/cmd_bootm.c Found configuration node
3181 104 common/cmd_bootm.c Got kernel subimage node offset
3182 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3183 105 common/cmd_bootm.c Kernel subimage hash verification OK
3184 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3185 106 common/cmd_bootm.c Architecture check OK
3186 -106 common/cmd_bootm.c Kernel subimage has wrong type
3187 107 common/cmd_bootm.c Kernel subimage type OK
3188 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3189 108 common/cmd_bootm.c Got kernel subimage data/size
3190 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3191 -109 common/cmd_bootm.c Can't get kernel subimage type
3192 -110 common/cmd_bootm.c Can't get kernel subimage comp
3193 -111 common/cmd_bootm.c Can't get kernel subimage os
3194 -112 common/cmd_bootm.c Can't get kernel subimage load address
3195 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3197 120 common/image.c Start initial ramdisk verification
3198 -120 common/image.c Ramdisk FIT image has incorrect format
3199 121 common/image.c Ramdisk FIT image has correct format
3200 122 common/image.c No ramdisk subimage unit name, using configuration
3201 -122 common/image.c Can't get configuration for ramdisk subimage
3202 123 common/image.c Ramdisk unit name specified
3203 -124 common/image.c Can't get ramdisk subimage node offset
3204 125 common/image.c Got ramdisk subimage node offset
3205 -125 common/image.c Ramdisk subimage hash verification failed
3206 126 common/image.c Ramdisk subimage hash verification OK
3207 -126 common/image.c Ramdisk subimage for unsupported architecture
3208 127 common/image.c Architecture check OK
3209 -127 common/image.c Can't get ramdisk subimage data/size
3210 128 common/image.c Got ramdisk subimage data/size
3211 129 common/image.c Can't get ramdisk load address
3212 -129 common/image.c Got ramdisk load address
3214 -130 common/cmd_doc.c Incorrect FIT image format
3215 131 common/cmd_doc.c FIT image format OK
3217 -140 common/cmd_ide.c Incorrect FIT image format
3218 141 common/cmd_ide.c FIT image format OK
3220 -150 common/cmd_nand.c Incorrect FIT image format
3221 151 common/cmd_nand.c FIT image format OK
3223 - legacy image format:
3224 CONFIG_IMAGE_FORMAT_LEGACY
3225 enables the legacy image format support in U-Boot.
3228 enabled if CONFIG_FIT_SIGNATURE is not defined.
3230 CONFIG_DISABLE_IMAGE_LEGACY
3231 disable the legacy image format
3233 This define is introduced, as the legacy image format is
3234 enabled per default for backward compatibility.
3236 - FIT image support:
3238 Enable support for the FIT uImage format.
3240 CONFIG_FIT_BEST_MATCH
3241 When no configuration is explicitly selected, default to the
3242 one whose fdt's compatibility field best matches that of
3243 U-Boot itself. A match is considered "best" if it matches the
3244 most specific compatibility entry of U-Boot's fdt's root node.
3245 The order of entries in the configuration's fdt is ignored.
3247 CONFIG_FIT_SIGNATURE
3248 This option enables signature verification of FIT uImages,
3249 using a hash signed and verified using RSA. See
3250 doc/uImage.FIT/signature.txt for more details.
3252 WARNING: When relying on signed FIT images with required
3253 signature check the legacy image format is default
3254 disabled. If a board need legacy image format support
3255 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3257 - Standalone program support:
3258 CONFIG_STANDALONE_LOAD_ADDR
3260 This option defines a board specific value for the
3261 address where standalone program gets loaded, thus
3262 overwriting the architecture dependent default
3265 - Frame Buffer Address:
3268 Define CONFIG_FB_ADDR if you want to use specific
3269 address for frame buffer. This is typically the case
3270 when using a graphics controller has separate video
3271 memory. U-Boot will then place the frame buffer at
3272 the given address instead of dynamically reserving it
3273 in system RAM by calling lcd_setmem(), which grabs
3274 the memory for the frame buffer depending on the
3275 configured panel size.
3277 Please see board_init_f function.
3279 - Automatic software updates via TFTP server
3281 CONFIG_UPDATE_TFTP_CNT_MAX
3282 CONFIG_UPDATE_TFTP_MSEC_MAX
3284 These options enable and control the auto-update feature;
3285 for a more detailed description refer to doc/README.update.
3287 - MTD Support (mtdparts command, UBI support)
3290 Adds the MTD device infrastructure from the Linux kernel.
3291 Needed for mtdparts command support.
3293 CONFIG_MTD_PARTITIONS
3295 Adds the MTD partitioning infrastructure from the Linux
3296 kernel. Needed for UBI support.
3301 Adds commands for interacting with MTD partitions formatted
3302 with the UBI flash translation layer
3304 Requires also defining CONFIG_RBTREE
3306 CONFIG_UBI_SILENCE_MSG
3308 Make the verbose messages from UBI stop printing. This leaves
3309 warnings and errors enabled.
3314 Adds commands for interacting with UBI volumes formatted as
3315 UBIFS. UBIFS is read-only in u-boot.
3317 Requires UBI support as well as CONFIG_LZO
3319 CONFIG_UBIFS_SILENCE_MSG
3321 Make the verbose messages from UBIFS stop printing. This leaves
3322 warnings and errors enabled.
3326 Enable building of SPL globally.
3329 LDSCRIPT for linking the SPL binary.
3331 CONFIG_SPL_MAX_FOOTPRINT
3332 Maximum size in memory allocated to the SPL, BSS included.
3333 When defined, the linker checks that the actual memory
3334 used by SPL from _start to __bss_end does not exceed it.
3335 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3336 must not be both defined at the same time.
3339 Maximum size of the SPL image (text, data, rodata, and
3340 linker lists sections), BSS excluded.
3341 When defined, the linker checks that the actual size does
3344 CONFIG_SPL_TEXT_BASE
3345 TEXT_BASE for linking the SPL binary.
3347 CONFIG_SPL_RELOC_TEXT_BASE
3348 Address to relocate to. If unspecified, this is equal to
3349 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3351 CONFIG_SPL_BSS_START_ADDR
3352 Link address for the BSS within the SPL binary.
3354 CONFIG_SPL_BSS_MAX_SIZE
3355 Maximum size in memory allocated to the SPL BSS.
3356 When defined, the linker checks that the actual memory used
3357 by SPL from __bss_start to __bss_end does not exceed it.
3358 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3359 must not be both defined at the same time.
3362 Adress of the start of the stack SPL will use
3364 CONFIG_SPL_RELOC_STACK
3365 Adress of the start of the stack SPL will use after
3366 relocation. If unspecified, this is equal to
3369 CONFIG_SYS_SPL_MALLOC_START
3370 Starting address of the malloc pool used in SPL.
3372 CONFIG_SYS_SPL_MALLOC_SIZE
3373 The size of the malloc pool used in SPL.
3375 CONFIG_SPL_FRAMEWORK
3376 Enable the SPL framework under common/. This framework
3377 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3378 NAND loading of the Linux Kernel.
3381 Enable booting directly to an OS from SPL.
3382 See also: doc/README.falcon
3384 CONFIG_SPL_DISPLAY_PRINT
3385 For ARM, enable an optional function to print more information
3386 about the running system.
3388 CONFIG_SPL_INIT_MINIMAL
3389 Arch init code should be built for a very small image
3391 CONFIG_SPL_LIBCOMMON_SUPPORT
3392 Support for common/libcommon.o in SPL binary
3394 CONFIG_SPL_LIBDISK_SUPPORT
3395 Support for disk/libdisk.o in SPL binary
3397 CONFIG_SPL_I2C_SUPPORT
3398 Support for drivers/i2c/libi2c.o in SPL binary
3400 CONFIG_SPL_GPIO_SUPPORT
3401 Support for drivers/gpio/libgpio.o in SPL binary
3403 CONFIG_SPL_MMC_SUPPORT
3404 Support for drivers/mmc/libmmc.o in SPL binary
3406 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3407 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3408 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3409 Address, size and partition on the MMC to load U-Boot from
3410 when the MMC is being used in raw mode.
3412 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3413 Sector to load kernel uImage from when MMC is being
3414 used in raw mode (for Falcon mode)
3416 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3417 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3418 Sector and number of sectors to load kernel argument
3419 parameters from when MMC is being used in raw mode
3422 CONFIG_SPL_FAT_SUPPORT
3423 Support for fs/fat/libfat.o in SPL binary
3425 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3426 Filename to read to load U-Boot when reading from FAT
3428 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3429 Filename to read to load kernel uImage when reading
3430 from FAT (for Falcon mode)
3432 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3433 Filename to read to load kernel argument parameters
3434 when reading from FAT (for Falcon mode)
3436 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3437 Set this for NAND SPL on PPC mpc83xx targets, so that
3438 start.S waits for the rest of the SPL to load before
3439 continuing (the hardware starts execution after just
3440 loading the first page rather than the full 4K).
3442 CONFIG_SPL_SKIP_RELOCATE
3443 Avoid SPL relocation
3445 CONFIG_SPL_NAND_BASE
3446 Include nand_base.c in the SPL. Requires
3447 CONFIG_SPL_NAND_DRIVERS.
3449 CONFIG_SPL_NAND_DRIVERS
3450 SPL uses normal NAND drivers, not minimal drivers.
3453 Include standard software ECC in the SPL
3455 CONFIG_SPL_NAND_SIMPLE
3456 Support for NAND boot using simple NAND drivers that
3457 expose the cmd_ctrl() interface.
3459 CONFIG_SPL_MTD_SUPPORT
3460 Support for the MTD subsystem within SPL. Useful for
3461 environment on NAND support within SPL.
3463 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3464 Set for the SPL on PPC mpc8xxx targets, support for
3465 drivers/ddr/fsl/libddr.o in SPL binary.
3467 CONFIG_SPL_COMMON_INIT_DDR
3468 Set for common ddr init with serial presence detect in
3471 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3472 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3473 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3474 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3475 CONFIG_SYS_NAND_ECCBYTES
3476 Defines the size and behavior of the NAND that SPL uses
3479 CONFIG_SPL_NAND_BOOT
3480 Add support NAND boot
3482 CONFIG_SYS_NAND_U_BOOT_OFFS
3483 Location in NAND to read U-Boot from
3485 CONFIG_SYS_NAND_U_BOOT_DST
3486 Location in memory to load U-Boot to
3488 CONFIG_SYS_NAND_U_BOOT_SIZE
3489 Size of image to load
3491 CONFIG_SYS_NAND_U_BOOT_START
3492 Entry point in loaded image to jump to
3494 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3495 Define this if you need to first read the OOB and then the
3496 data. This is used for example on davinci plattforms.
3498 CONFIG_SPL_OMAP3_ID_NAND
3499 Support for an OMAP3-specific set of functions to return the
3500 ID and MFR of the first attached NAND chip, if present.
3502 CONFIG_SPL_SERIAL_SUPPORT
3503 Support for drivers/serial/libserial.o in SPL binary
3505 CONFIG_SPL_SPI_FLASH_SUPPORT
3506 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3508 CONFIG_SPL_SPI_SUPPORT
3509 Support for drivers/spi/libspi.o in SPL binary
3511 CONFIG_SPL_RAM_DEVICE
3512 Support for running image already present in ram, in SPL binary
3514 CONFIG_SPL_LIBGENERIC_SUPPORT
3515 Support for lib/libgeneric.o in SPL binary
3517 CONFIG_SPL_ENV_SUPPORT
3518 Support for the environment operating in SPL binary
3520 CONFIG_SPL_NET_SUPPORT
3521 Support for the net/libnet.o in SPL binary.
3522 It conflicts with SPL env from storage medium specified by
3523 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3526 Image offset to which the SPL should be padded before appending
3527 the SPL payload. By default, this is defined as
3528 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3529 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3530 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3533 Final target image containing SPL and payload. Some SPLs
3534 use an arch-specific makefile fragment instead, for
3535 example if more than one image needs to be produced.
3537 CONFIG_FIT_SPL_PRINT
3538 Printing information about a FIT image adds quite a bit of
3539 code to SPL. So this is normally disabled in SPL. Use this
3540 option to re-enable it. This will affect the output of the
3541 bootm command when booting a FIT image.
3545 Enable building of TPL globally.
3548 Image offset to which the TPL should be padded before appending
3549 the TPL payload. By default, this is defined as
3550 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3551 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3552 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3557 [so far only for SMDK2400 boards]
3559 - Modem support enable:
3560 CONFIG_MODEM_SUPPORT
3562 - RTS/CTS Flow control enable:
3565 - Modem debug support:
3566 CONFIG_MODEM_SUPPORT_DEBUG
3568 Enables debugging stuff (char screen[1024], dbg())
3569 for modem support. Useful only with BDI2000.
3571 - Interrupt support (PPC):
3573 There are common interrupt_init() and timer_interrupt()
3574 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3575 for CPU specific initialization. interrupt_init_cpu()
3576 should set decrementer_count to appropriate value. If
3577 CPU resets decrementer automatically after interrupt
3578 (ppc4xx) it should set decrementer_count to zero.
3579 timer_interrupt() calls timer_interrupt_cpu() for CPU
3580 specific handling. If board has watchdog / status_led
3581 / other_activity_monitor it works automatically from
3582 general timer_interrupt().
3586 In the target system modem support is enabled when a
3587 specific key (key combination) is pressed during
3588 power-on. Otherwise U-Boot will boot normally
3589 (autoboot). The key_pressed() function is called from
3590 board_init(). Currently key_pressed() is a dummy
3591 function, returning 1 and thus enabling modem
3594 If there are no modem init strings in the
3595 environment, U-Boot proceed to autoboot; the
3596 previous output (banner, info printfs) will be
3599 See also: doc/README.Modem
3601 Board initialization settings:
3602 ------------------------------
3604 During Initialization u-boot calls a number of board specific functions
3605 to allow the preparation of board specific prerequisites, e.g. pin setup
3606 before drivers are initialized. To enable these callbacks the
3607 following configuration macros have to be defined. Currently this is
3608 architecture specific, so please check arch/your_architecture/lib/board.c
3609 typically in board_init_f() and board_init_r().
3611 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3612 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3613 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3614 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3616 Configuration Settings:
3617 -----------------------
3619 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3620 Optionally it can be defined to support 64-bit memory commands.
3622 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3623 undefine this when you're short of memory.
3625 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3626 width of the commands listed in the 'help' command output.
3628 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3629 prompt for user input.
3631 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3633 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3635 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3637 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3638 the application (usually a Linux kernel) when it is
3641 - CONFIG_SYS_BAUDRATE_TABLE:
3642 List of legal baudrate settings for this board.
3644 - CONFIG_SYS_CONSOLE_INFO_QUIET
3645 Suppress display of console information at boot.
3647 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3648 If the board specific function
3649 extern int overwrite_console (void);
3650 returns 1, the stdin, stderr and stdout are switched to the
3651 serial port, else the settings in the environment are used.
3653 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3654 Enable the call to overwrite_console().
3656 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3657 Enable overwrite of previous console environment settings.
3659 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3660 Begin and End addresses of the area used by the
3663 - CONFIG_SYS_ALT_MEMTEST:
3664 Enable an alternate, more extensive memory test.
3666 - CONFIG_SYS_MEMTEST_SCRATCH:
3667 Scratch address used by the alternate memory test
3668 You only need to set this if address zero isn't writeable
3670 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3671 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3672 this specified memory area will get subtracted from the top
3673 (end) of RAM and won't get "touched" at all by U-Boot. By
3674 fixing up gd->ram_size the Linux kernel should gets passed
3675 the now "corrected" memory size and won't touch it either.
3676 This should work for arch/ppc and arch/powerpc. Only Linux
3677 board ports in arch/powerpc with bootwrapper support that
3678 recalculate the memory size from the SDRAM controller setup
3679 will have to get fixed in Linux additionally.
3681 This option can be used as a workaround for the 440EPx/GRx
3682 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3685 WARNING: Please make sure that this value is a multiple of
3686 the Linux page size (normally 4k). If this is not the case,
3687 then the end address of the Linux memory will be located at a
3688 non page size aligned address and this could cause major
3691 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3692 Enable temporary baudrate change while serial download
3694 - CONFIG_SYS_SDRAM_BASE:
3695 Physical start address of SDRAM. _Must_ be 0 here.
3697 - CONFIG_SYS_MBIO_BASE:
3698 Physical start address of Motherboard I/O (if using a
3701 - CONFIG_SYS_FLASH_BASE:
3702 Physical start address of Flash memory.
3704 - CONFIG_SYS_MONITOR_BASE:
3705 Physical start address of boot monitor code (set by
3706 make config files to be same as the text base address
3707 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3708 CONFIG_SYS_FLASH_BASE when booting from flash.
3710 - CONFIG_SYS_MONITOR_LEN:
3711 Size of memory reserved for monitor code, used to
3712 determine _at_compile_time_ (!) if the environment is
3713 embedded within the U-Boot image, or in a separate
3716 - CONFIG_SYS_MALLOC_LEN:
3717 Size of DRAM reserved for malloc() use.
3719 - CONFIG_SYS_BOOTM_LEN:
3720 Normally compressed uImages are limited to an
3721 uncompressed size of 8 MBytes. If this is not enough,
3722 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3723 to adjust this setting to your needs.
3725 - CONFIG_SYS_BOOTMAPSZ:
3726 Maximum size of memory mapped by the startup code of
3727 the Linux kernel; all data that must be processed by
3728 the Linux kernel (bd_info, boot arguments, FDT blob if
3729 used) must be put below this limit, unless "bootm_low"
3730 environment variable is defined and non-zero. In such case
3731 all data for the Linux kernel must be between "bootm_low"
3732 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3733 variable "bootm_mapsize" will override the value of
3734 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3735 then the value in "bootm_size" will be used instead.
3737 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3738 Enable initrd_high functionality. If defined then the
3739 initrd_high feature is enabled and the bootm ramdisk subcommand
3742 - CONFIG_SYS_BOOT_GET_CMDLINE:
3743 Enables allocating and saving kernel cmdline in space between
3744 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3746 - CONFIG_SYS_BOOT_GET_KBD:
3747 Enables allocating and saving a kernel copy of the bd_info in
3748 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3750 - CONFIG_SYS_MAX_FLASH_BANKS:
3751 Max number of Flash memory banks
3753 - CONFIG_SYS_MAX_FLASH_SECT:
3754 Max number of sectors on a Flash chip
3756 - CONFIG_SYS_FLASH_ERASE_TOUT:
3757 Timeout for Flash erase operations (in ms)
3759 - CONFIG_SYS_FLASH_WRITE_TOUT:
3760 Timeout for Flash write operations (in ms)
3762 - CONFIG_SYS_FLASH_LOCK_TOUT
3763 Timeout for Flash set sector lock bit operation (in ms)
3765 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3766 Timeout for Flash clear lock bits operation (in ms)
3768 - CONFIG_SYS_FLASH_PROTECTION
3769 If defined, hardware flash sectors protection is used
3770 instead of U-Boot software protection.
3772 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3774 Enable TFTP transfers directly to flash memory;
3775 without this option such a download has to be
3776 performed in two steps: (1) download to RAM, and (2)
3777 copy from RAM to flash.
3779 The two-step approach is usually more reliable, since
3780 you can check if the download worked before you erase
3781 the flash, but in some situations (when system RAM is
3782 too limited to allow for a temporary copy of the
3783 downloaded image) this option may be very useful.
3785 - CONFIG_SYS_FLASH_CFI:
3786 Define if the flash driver uses extra elements in the
3787 common flash structure for storing flash geometry.
3789 - CONFIG_FLASH_CFI_DRIVER
3790 This option also enables the building of the cfi_flash driver
3791 in the drivers directory
3793 - CONFIG_FLASH_CFI_MTD
3794 This option enables the building of the cfi_mtd driver
3795 in the drivers directory. The driver exports CFI flash
3798 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3799 Use buffered writes to flash.
3801 - CONFIG_FLASH_SPANSION_S29WS_N
3802 s29ws-n MirrorBit flash has non-standard addresses for buffered
3805 - CONFIG_SYS_FLASH_QUIET_TEST
3806 If this option is defined, the common CFI flash doesn't
3807 print it's warning upon not recognized FLASH banks. This
3808 is useful, if some of the configured banks are only
3809 optionally available.
3811 - CONFIG_FLASH_SHOW_PROGRESS
3812 If defined (must be an integer), print out countdown
3813 digits and dots. Recommended value: 45 (9..1) for 80
3814 column displays, 15 (3..1) for 40 column displays.
3816 - CONFIG_FLASH_VERIFY
3817 If defined, the content of the flash (destination) is compared
3818 against the source after the write operation. An error message
3819 will be printed when the contents are not identical.
3820 Please note that this option is useless in nearly all cases,
3821 since such flash programming errors usually are detected earlier
3822 while unprotecting/erasing/programming. Please only enable
3823 this option if you really know what you are doing.
3825 - CONFIG_SYS_RX_ETH_BUFFER:
3826 Defines the number of Ethernet receive buffers. On some
3827 Ethernet controllers it is recommended to set this value
3828 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3829 buffers can be full shortly after enabling the interface
3830 on high Ethernet traffic.
3831 Defaults to 4 if not defined.
3833 - CONFIG_ENV_MAX_ENTRIES
3835 Maximum number of entries in the hash table that is used
3836 internally to store the environment settings. The default
3837 setting is supposed to be generous and should work in most
3838 cases. This setting can be used to tune behaviour; see
3839 lib/hashtable.c for details.
3841 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3842 - CONFIG_ENV_FLAGS_LIST_STATIC
3843 Enable validation of the values given to environment variables when
3844 calling env set. Variables can be restricted to only decimal,
3845 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3846 the variables can also be restricted to IP address or MAC address.
3848 The format of the list is:
3849 type_attribute = [s|d|x|b|i|m]
3850 access_atribute = [a|r|o|c]
3851 attributes = type_attribute[access_atribute]
3852 entry = variable_name[:attributes]
3855 The type attributes are:
3856 s - String (default)
3859 b - Boolean ([1yYtT|0nNfF])
3863 The access attributes are:
3869 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3870 Define this to a list (string) to define the ".flags"
3871 envirnoment variable in the default or embedded environment.
3873 - CONFIG_ENV_FLAGS_LIST_STATIC
3874 Define this to a list (string) to define validation that
3875 should be done if an entry is not found in the ".flags"
3876 environment variable. To override a setting in the static
3877 list, simply add an entry for the same variable name to the
3880 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3881 If defined, don't allow the -f switch to env set override variable
3884 - CONFIG_SYS_GENERIC_BOARD
3885 This selects the architecture-generic board system instead of the
3886 architecture-specific board files. It is intended to move boards
3887 to this new framework over time. Defining this will disable the
3888 arch/foo/lib/board.c file and use common/board_f.c and
3889 common/board_r.c instead. To use this option your architecture
3890 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3891 its config.mk file). If you find problems enabling this option on
3892 your board please report the problem and send patches!
3894 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3895 This is set by OMAP boards for the max time that reset should
3896 be asserted. See doc/README.omap-reset-time for details on how
3897 the value can be calulated on a given board.
3899 The following definitions that deal with the placement and management
3900 of environment data (variable area); in general, we support the
3901 following configurations:
3903 - CONFIG_BUILD_ENVCRC:
3905 Builds up envcrc with the target environment so that external utils
3906 may easily extract it and embed it in final U-Boot images.
3908 - CONFIG_ENV_IS_IN_FLASH:
3910 Define this if the environment is in flash memory.
3912 a) The environment occupies one whole flash sector, which is
3913 "embedded" in the text segment with the U-Boot code. This
3914 happens usually with "bottom boot sector" or "top boot
3915 sector" type flash chips, which have several smaller
3916 sectors at the start or the end. For instance, such a
3917 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3918 such a case you would place the environment in one of the
3919 4 kB sectors - with U-Boot code before and after it. With
3920 "top boot sector" type flash chips, you would put the
3921 environment in one of the last sectors, leaving a gap
3922 between U-Boot and the environment.
3924 - CONFIG_ENV_OFFSET:
3926 Offset of environment data (variable area) to the
3927 beginning of flash memory; for instance, with bottom boot
3928 type flash chips the second sector can be used: the offset
3929 for this sector is given here.
3931 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3935 This is just another way to specify the start address of
3936 the flash sector containing the environment (instead of
3939 - CONFIG_ENV_SECT_SIZE:
3941 Size of the sector containing the environment.
3944 b) Sometimes flash chips have few, equal sized, BIG sectors.
3945 In such a case you don't want to spend a whole sector for
3950 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3951 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3952 of this flash sector for the environment. This saves
3953 memory for the RAM copy of the environment.
3955 It may also save flash memory if you decide to use this
3956 when your environment is "embedded" within U-Boot code,
3957 since then the remainder of the flash sector could be used
3958 for U-Boot code. It should be pointed out that this is
3959 STRONGLY DISCOURAGED from a robustness point of view:
3960 updating the environment in flash makes it always
3961 necessary to erase the WHOLE sector. If something goes
3962 wrong before the contents has been restored from a copy in
3963 RAM, your target system will be dead.
3965 - CONFIG_ENV_ADDR_REDUND
3966 CONFIG_ENV_SIZE_REDUND
3968 These settings describe a second storage area used to hold
3969 a redundant copy of the environment data, so that there is
3970 a valid backup copy in case there is a power failure during
3971 a "saveenv" operation.
3973 BE CAREFUL! Any changes to the flash layout, and some changes to the
3974 source code will make it necessary to adapt <board>/u-boot.lds*
3978 - CONFIG_ENV_IS_IN_NVRAM:
3980 Define this if you have some non-volatile memory device
3981 (NVRAM, battery buffered SRAM) which you want to use for the
3987 These two #defines are used to determine the memory area you
3988 want to use for environment. It is assumed that this memory
3989 can just be read and written to, without any special
3992 BE CAREFUL! The first access to the environment happens quite early
3993 in U-Boot initalization (when we try to get the setting of for the
3994 console baudrate). You *MUST* have mapped your NVRAM area then, or
3997 Please note that even with NVRAM we still use a copy of the
3998 environment in RAM: we could work on NVRAM directly, but we want to
3999 keep settings there always unmodified except somebody uses "saveenv"
4000 to save the current settings.
4003 - CONFIG_ENV_IS_IN_EEPROM:
4005 Use this if you have an EEPROM or similar serial access
4006 device and a driver for it.
4008 - CONFIG_ENV_OFFSET:
4011 These two #defines specify the offset and size of the
4012 environment area within the total memory of your EEPROM.
4014 - CONFIG_SYS_I2C_EEPROM_ADDR:
4015 If defined, specified the chip address of the EEPROM device.
4016 The default address is zero.
4018 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4019 If defined, the number of bits used to address bytes in a
4020 single page in the EEPROM device. A 64 byte page, for example
4021 would require six bits.
4023 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4024 If defined, the number of milliseconds to delay between
4025 page writes. The default is zero milliseconds.
4027 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4028 The length in bytes of the EEPROM memory array address. Note
4029 that this is NOT the chip address length!
4031 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4032 EEPROM chips that implement "address overflow" are ones
4033 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4034 address and the extra bits end up in the "chip address" bit
4035 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4038 Note that we consider the length of the address field to
4039 still be one byte because the extra address bits are hidden
4040 in the chip address.
4042 - CONFIG_SYS_EEPROM_SIZE:
4043 The size in bytes of the EEPROM device.
4045 - CONFIG_ENV_EEPROM_IS_ON_I2C
4046 define this, if you have I2C and SPI activated, and your
4047 EEPROM, which holds the environment, is on the I2C bus.
4049 - CONFIG_I2C_ENV_EEPROM_BUS
4050 if you have an Environment on an EEPROM reached over
4051 I2C muxes, you can define here, how to reach this
4052 EEPROM. For example:
4054 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4056 EEPROM which holds the environment, is reached over
4057 a pca9547 i2c mux with address 0x70, channel 3.
4059 - CONFIG_ENV_IS_IN_DATAFLASH:
4061 Define this if you have a DataFlash memory device which you
4062 want to use for the environment.
4064 - CONFIG_ENV_OFFSET:
4068 These three #defines specify the offset and size of the
4069 environment area within the total memory of your DataFlash placed
4070 at the specified address.
4072 - CONFIG_ENV_IS_IN_REMOTE:
4074 Define this if you have a remote memory space which you
4075 want to use for the local device's environment.
4080 These two #defines specify the address and size of the
4081 environment area within the remote memory space. The
4082 local device can get the environment from remote memory
4083 space by SRIO or PCIE links.
4085 BE CAREFUL! For some special cases, the local device can not use
4086 "saveenv" command. For example, the local device will get the
4087 environment stored in a remote NOR flash by SRIO or PCIE link,
4088 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4090 - CONFIG_ENV_IS_IN_NAND:
4092 Define this if you have a NAND device which you want to use
4093 for the environment.
4095 - CONFIG_ENV_OFFSET:
4098 These two #defines specify the offset and size of the environment
4099 area within the first NAND device. CONFIG_ENV_OFFSET must be
4100 aligned to an erase block boundary.
4102 - CONFIG_ENV_OFFSET_REDUND (optional):
4104 This setting describes a second storage area of CONFIG_ENV_SIZE
4105 size used to hold a redundant copy of the environment data, so
4106 that there is a valid backup copy in case there is a power failure
4107 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4108 aligned to an erase block boundary.
4110 - CONFIG_ENV_RANGE (optional):
4112 Specifies the length of the region in which the environment
4113 can be written. This should be a multiple of the NAND device's
4114 block size. Specifying a range with more erase blocks than
4115 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4116 the range to be avoided.
4118 - CONFIG_ENV_OFFSET_OOB (optional):
4120 Enables support for dynamically retrieving the offset of the
4121 environment from block zero's out-of-band data. The
4122 "nand env.oob" command can be used to record this offset.
4123 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4124 using CONFIG_ENV_OFFSET_OOB.
4126 - CONFIG_NAND_ENV_DST
4128 Defines address in RAM to which the nand_spl code should copy the
4129 environment. If redundant environment is used, it will be copied to
4130 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4132 - CONFIG_ENV_IS_IN_UBI:
4134 Define this if you have an UBI volume that you want to use for the
4135 environment. This has the benefit of wear-leveling the environment
4136 accesses, which is important on NAND.
4138 - CONFIG_ENV_UBI_PART:
4140 Define this to a string that is the mtd partition containing the UBI.
4142 - CONFIG_ENV_UBI_VOLUME:
4144 Define this to the name of the volume that you want to store the
4147 - CONFIG_ENV_UBI_VOLUME_REDUND:
4149 Define this to the name of another volume to store a second copy of
4150 the environment in. This will enable redundant environments in UBI.
4151 It is assumed that both volumes are in the same MTD partition.
4153 - CONFIG_UBI_SILENCE_MSG
4154 - CONFIG_UBIFS_SILENCE_MSG
4156 You will probably want to define these to avoid a really noisy system
4157 when storing the env in UBI.
4159 - CONFIG_ENV_IS_IN_MMC:
4161 Define this if you have an MMC device which you want to use for the
4164 - CONFIG_SYS_MMC_ENV_DEV:
4166 Specifies which MMC device the environment is stored in.
4168 - CONFIG_SYS_MMC_ENV_PART (optional):
4170 Specifies which MMC partition the environment is stored in. If not
4171 set, defaults to partition 0, the user area. Common values might be
4172 1 (first MMC boot partition), 2 (second MMC boot partition).
4174 - CONFIG_ENV_OFFSET:
4177 These two #defines specify the offset and size of the environment
4178 area within the specified MMC device.
4180 If offset is positive (the usual case), it is treated as relative to
4181 the start of the MMC partition. If offset is negative, it is treated
4182 as relative to the end of the MMC partition. This can be useful if
4183 your board may be fitted with different MMC devices, which have
4184 different sizes for the MMC partitions, and you always want the
4185 environment placed at the very end of the partition, to leave the
4186 maximum possible space before it, to store other data.
4188 These two values are in units of bytes, but must be aligned to an
4189 MMC sector boundary.
4191 - CONFIG_ENV_OFFSET_REDUND (optional):
4193 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4194 hold a redundant copy of the environment data. This provides a
4195 valid backup copy in case the other copy is corrupted, e.g. due
4196 to a power failure during a "saveenv" operation.
4198 This value may also be positive or negative; this is handled in the
4199 same way as CONFIG_ENV_OFFSET.
4201 This value is also in units of bytes, but must also be aligned to
4202 an MMC sector boundary.
4204 - CONFIG_ENV_SIZE_REDUND (optional):
4206 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4207 set. If this value is set, it must be set to the same value as
4210 - CONFIG_SYS_SPI_INIT_OFFSET
4212 Defines offset to the initial SPI buffer area in DPRAM. The
4213 area is used at an early stage (ROM part) if the environment
4214 is configured to reside in the SPI EEPROM: We need a 520 byte
4215 scratch DPRAM area. It is used between the two initialization
4216 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4217 to be a good choice since it makes it far enough from the
4218 start of the data area as well as from the stack pointer.
4220 Please note that the environment is read-only until the monitor
4221 has been relocated to RAM and a RAM copy of the environment has been
4222 created; also, when using EEPROM you will have to use getenv_f()
4223 until then to read environment variables.
4225 The environment is protected by a CRC32 checksum. Before the monitor
4226 is relocated into RAM, as a result of a bad CRC you will be working
4227 with the compiled-in default environment - *silently*!!! [This is
4228 necessary, because the first environment variable we need is the
4229 "baudrate" setting for the console - if we have a bad CRC, we don't
4230 have any device yet where we could complain.]
4232 Note: once the monitor has been relocated, then it will complain if
4233 the default environment is used; a new CRC is computed as soon as you
4234 use the "saveenv" command to store a valid environment.
4236 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4237 Echo the inverted Ethernet link state to the fault LED.
4239 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4240 also needs to be defined.
4242 - CONFIG_SYS_FAULT_MII_ADDR:
4243 MII address of the PHY to check for the Ethernet link state.
4245 - CONFIG_NS16550_MIN_FUNCTIONS:
4246 Define this if you desire to only have use of the NS16550_init
4247 and NS16550_putc functions for the serial driver located at
4248 drivers/serial/ns16550.c. This option is useful for saving
4249 space for already greatly restricted images, including but not
4250 limited to NAND_SPL configurations.
4252 - CONFIG_DISPLAY_BOARDINFO
4253 Display information about the board that U-Boot is running on
4254 when U-Boot starts up. The board function checkboard() is called
4257 - CONFIG_DISPLAY_BOARDINFO_LATE
4258 Similar to the previous option, but display this information
4259 later, once stdio is running and output goes to the LCD, if
4262 Low Level (hardware related) configuration options:
4263 ---------------------------------------------------
4265 - CONFIG_SYS_CACHELINE_SIZE:
4266 Cache Line Size of the CPU.
4268 - CONFIG_SYS_DEFAULT_IMMR:
4269 Default address of the IMMR after system reset.
4271 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4272 and RPXsuper) to be able to adjust the position of
4273 the IMMR register after a reset.
4275 - CONFIG_SYS_CCSRBAR_DEFAULT:
4276 Default (power-on reset) physical address of CCSR on Freescale
4279 - CONFIG_SYS_CCSRBAR:
4280 Virtual address of CCSR. On a 32-bit build, this is typically
4281 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4283 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4284 for cross-platform code that uses that macro instead.
4286 - CONFIG_SYS_CCSRBAR_PHYS:
4287 Physical address of CCSR. CCSR can be relocated to a new
4288 physical address, if desired. In this case, this macro should
4289 be set to that address. Otherwise, it should be set to the
4290 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4291 is typically relocated on 36-bit builds. It is recommended
4292 that this macro be defined via the _HIGH and _LOW macros:
4294 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4295 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4297 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4298 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4299 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4300 used in assembly code, so it must not contain typecasts or
4301 integer size suffixes (e.g. "ULL").
4303 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4304 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4305 used in assembly code, so it must not contain typecasts or
4306 integer size suffixes (e.g. "ULL").
4308 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4309 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4310 forced to a value that ensures that CCSR is not relocated.
4312 - Floppy Disk Support:
4313 CONFIG_SYS_FDC_DRIVE_NUMBER
4315 the default drive number (default value 0)
4317 CONFIG_SYS_ISA_IO_STRIDE
4319 defines the spacing between FDC chipset registers
4322 CONFIG_SYS_ISA_IO_OFFSET
4324 defines the offset of register from address. It
4325 depends on which part of the data bus is connected to
4326 the FDC chipset. (default value 0)
4328 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4329 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4332 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4333 fdc_hw_init() is called at the beginning of the FDC
4334 setup. fdc_hw_init() must be provided by the board
4335 source code. It is used to make hardware dependant
4339 Most IDE controllers were designed to be connected with PCI
4340 interface. Only few of them were designed for AHB interface.
4341 When software is doing ATA command and data transfer to
4342 IDE devices through IDE-AHB controller, some additional
4343 registers accessing to these kind of IDE-AHB controller
4346 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4347 DO NOT CHANGE unless you know exactly what you're
4348 doing! (11-4) [MPC8xx/82xx systems only]
4350 - CONFIG_SYS_INIT_RAM_ADDR:
4352 Start address of memory area that can be used for
4353 initial data and stack; please note that this must be
4354 writable memory that is working WITHOUT special
4355 initialization, i. e. you CANNOT use normal RAM which
4356 will become available only after programming the
4357 memory controller and running certain initialization
4360 U-Boot uses the following memory types:
4361 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4362 - MPC824X: data cache
4363 - PPC4xx: data cache
4365 - CONFIG_SYS_GBL_DATA_OFFSET:
4367 Offset of the initial data structure in the memory
4368 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4369 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4370 data is located at the end of the available space
4371 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4372 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4373 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4374 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4377 On the MPC824X (or other systems that use the data
4378 cache for initial memory) the address chosen for
4379 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4380 point to an otherwise UNUSED address space between
4381 the top of RAM and the start of the PCI space.
4383 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4385 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4387 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4389 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4391 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4393 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4395 - CONFIG_SYS_OR_TIMING_SDRAM:
4398 - CONFIG_SYS_MAMR_PTA:
4399 periodic timer for refresh
4401 - CONFIG_SYS_DER: Debug Event Register (37-47)
4403 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4404 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4405 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4406 CONFIG_SYS_BR1_PRELIM:
4407 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4409 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4410 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4411 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4412 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4414 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4415 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4416 Machine Mode Register and Memory Periodic Timer
4417 Prescaler definitions (SDRAM timing)
4419 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4420 enable I2C microcode relocation patch (MPC8xx);
4421 define relocation offset in DPRAM [DSP2]
4423 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4424 enable SMC microcode relocation patch (MPC8xx);
4425 define relocation offset in DPRAM [SMC1]
4427 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4428 enable SPI microcode relocation patch (MPC8xx);
4429 define relocation offset in DPRAM [SCC4]
4431 - CONFIG_SYS_USE_OSCCLK:
4432 Use OSCM clock mode on MBX8xx board. Be careful,
4433 wrong setting might damage your board. Read
4434 doc/README.MBX before setting this variable!
4436 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4437 Offset of the bootmode word in DPRAM used by post
4438 (Power On Self Tests). This definition overrides
4439 #define'd default value in commproc.h resp.
4442 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4443 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4444 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4445 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4446 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4447 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4448 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4449 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4450 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4452 - CONFIG_PCI_DISABLE_PCIE:
4453 Disable PCI-Express on systems where it is supported but not
4456 - CONFIG_PCI_ENUM_ONLY
4457 Only scan through and get the devices on the busses.
4458 Don't do any setup work, presumably because someone or
4459 something has already done it, and we don't need to do it
4460 a second time. Useful for platforms that are pre-booted
4461 by coreboot or similar.
4463 - CONFIG_PCI_INDIRECT_BRIDGE:
4464 Enable support for indirect PCI bridges.
4467 Chip has SRIO or not
4470 Board has SRIO 1 port available
4473 Board has SRIO 2 port available
4475 - CONFIG_SRIO_PCIE_BOOT_MASTER
4476 Board can support master function for Boot from SRIO and PCIE
4478 - CONFIG_SYS_SRIOn_MEM_VIRT:
4479 Virtual Address of SRIO port 'n' memory region
4481 - CONFIG_SYS_SRIOn_MEM_PHYS:
4482 Physical Address of SRIO port 'n' memory region
4484 - CONFIG_SYS_SRIOn_MEM_SIZE:
4485 Size of SRIO port 'n' memory region
4487 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4488 Defined to tell the NAND controller that the NAND chip is using
4490 Not all NAND drivers use this symbol.
4491 Example of drivers that use it:
4492 - drivers/mtd/nand/ndfc.c
4493 - drivers/mtd/nand/mxc_nand.c
4495 - CONFIG_SYS_NDFC_EBC0_CFG
4496 Sets the EBC0_CFG register for the NDFC. If not defined
4497 a default value will be used.
4500 Get DDR timing information from an I2C EEPROM. Common
4501 with pluggable memory modules such as SODIMMs
4504 I2C address of the SPD EEPROM
4506 - CONFIG_SYS_SPD_BUS_NUM
4507 If SPD EEPROM is on an I2C bus other than the first
4508 one, specify here. Note that the value must resolve
4509 to something your driver can deal with.
4511 - CONFIG_SYS_DDR_RAW_TIMING
4512 Get DDR timing information from other than SPD. Common with
4513 soldered DDR chips onboard without SPD. DDR raw timing
4514 parameters are extracted from datasheet and hard-coded into
4515 header files or board specific files.
4517 - CONFIG_FSL_DDR_INTERACTIVE
4518 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4520 - CONFIG_SYS_83XX_DDR_USES_CS0
4521 Only for 83xx systems. If specified, then DDR should
4522 be configured using CS0 and CS1 instead of CS2 and CS3.
4524 - CONFIG_ETHER_ON_FEC[12]
4525 Define to enable FEC[12] on a 8xx series processor.
4527 - CONFIG_FEC[12]_PHY
4528 Define to the hardcoded PHY address which corresponds
4529 to the given FEC; i. e.
4530 #define CONFIG_FEC1_PHY 4
4531 means that the PHY with address 4 is connected to FEC1
4533 When set to -1, means to probe for first available.
4535 - CONFIG_FEC[12]_PHY_NORXERR
4536 The PHY does not have a RXERR line (RMII only).
4537 (so program the FEC to ignore it).
4540 Enable RMII mode for all FECs.
4541 Note that this is a global option, we can't
4542 have one FEC in standard MII mode and another in RMII mode.
4544 - CONFIG_CRC32_VERIFY
4545 Add a verify option to the crc32 command.
4548 => crc32 -v <address> <count> <crc32>
4550 Where address/count indicate a memory area
4551 and crc32 is the correct crc32 which the
4555 Add the "loopw" memory command. This only takes effect if
4556 the memory commands are activated globally (CONFIG_CMD_MEM).
4559 Add the "mdc" and "mwc" memory commands. These are cyclic
4564 This command will print 4 bytes (10,11,12,13) each 500 ms.
4566 => mwc.l 100 12345678 10
4567 This command will write 12345678 to address 100 all 10 ms.
4569 This only takes effect if the memory commands are activated
4570 globally (CONFIG_CMD_MEM).
4572 - CONFIG_SKIP_LOWLEVEL_INIT
4573 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4574 low level initializations (like setting up the memory
4575 controller) are omitted and/or U-Boot does not
4576 relocate itself into RAM.
4578 Normally this variable MUST NOT be defined. The only
4579 exception is when U-Boot is loaded (to RAM) by some
4580 other boot loader or by a debugger which performs
4581 these initializations itself.
4584 Modifies the behaviour of start.S when compiling a loader
4585 that is executed before the actual U-Boot. E.g. when
4586 compiling a NAND SPL.
4589 Modifies the behaviour of start.S when compiling a loader
4590 that is executed after the SPL and before the actual U-Boot.
4591 It is loaded by the SPL.
4593 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4594 Only for 85xx systems. If this variable is specified, the section
4595 .resetvec is not kept and the section .bootpg is placed in the
4596 previous 4k of the .text section.
4598 - CONFIG_ARCH_MAP_SYSMEM
4599 Generally U-Boot (and in particular the md command) uses
4600 effective address. It is therefore not necessary to regard
4601 U-Boot address as virtual addresses that need to be translated
4602 to physical addresses. However, sandbox requires this, since
4603 it maintains its own little RAM buffer which contains all
4604 addressable memory. This option causes some memory accesses
4605 to be mapped through map_sysmem() / unmap_sysmem().
4607 - CONFIG_USE_ARCH_MEMCPY
4608 CONFIG_USE_ARCH_MEMSET
4609 If these options are used a optimized version of memcpy/memset will
4610 be used if available. These functions may be faster under some
4611 conditions but may increase the binary size.
4613 - CONFIG_X86_RESET_VECTOR
4614 If defined, the x86 reset vector code is included. This is not
4615 needed when U-Boot is running from Coreboot.
4618 Defines the MPU clock speed (in MHz).
4620 NOTE : currently only supported on AM335x platforms.
4622 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4623 Enables the RTC32K OSC on AM33xx based plattforms
4625 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4626 Option to disable subpage write in NAND driver
4627 driver that uses this:
4628 drivers/mtd/nand/davinci_nand.c
4630 Freescale QE/FMAN Firmware Support:
4631 -----------------------------------
4633 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4634 loading of "firmware", which is encoded in the QE firmware binary format.
4635 This firmware often needs to be loaded during U-Boot booting, so macros
4636 are used to identify the storage device (NOR flash, SPI, etc) and the address
4639 - CONFIG_SYS_FMAN_FW_ADDR
4640 The address in the storage device where the FMAN microcode is located. The
4641 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4644 - CONFIG_SYS_QE_FW_ADDR
4645 The address in the storage device where the QE microcode is located. The
4646 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4649 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4650 The maximum possible size of the firmware. The firmware binary format
4651 has a field that specifies the actual size of the firmware, but it
4652 might not be possible to read any part of the firmware unless some
4653 local storage is allocated to hold the entire firmware first.
4655 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4656 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4657 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4658 virtual address in NOR flash.
4660 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4661 Specifies that QE/FMAN firmware is located in NAND flash.
4662 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4664 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4665 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4666 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4668 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4669 Specifies that QE/FMAN firmware is located on the primary SPI
4670 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4672 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4673 Specifies that QE/FMAN firmware is located in the remote (master)
4674 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4675 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4676 window->master inbound window->master LAW->the ucode address in
4677 master's memory space.
4679 Building the Software:
4680 ======================
4682 Building U-Boot has been tested in several native build environments
4683 and in many different cross environments. Of course we cannot support
4684 all possibly existing versions of cross development tools in all
4685 (potentially obsolete) versions. In case of tool chain problems we
4686 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4687 which is extensively used to build and test U-Boot.
4689 If you are not using a native environment, it is assumed that you
4690 have GNU cross compiling tools available in your path. In this case,
4691 you must set the environment variable CROSS_COMPILE in your shell.
4692 Note that no changes to the Makefile or any other source files are
4693 necessary. For example using the ELDK on a 4xx CPU, please enter:
4695 $ CROSS_COMPILE=ppc_4xx-
4696 $ export CROSS_COMPILE
4698 Note: If you wish to generate Windows versions of the utilities in
4699 the tools directory you can use the MinGW toolchain
4700 (http://www.mingw.org). Set your HOST tools to the MinGW
4701 toolchain and execute 'make tools'. For example:
4703 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4705 Binaries such as tools/mkimage.exe will be created which can
4706 be executed on computers running Windows.
4708 U-Boot is intended to be simple to build. After installing the
4709 sources you must configure U-Boot for one specific board type. This
4714 where "NAME_config" is the name of one of the existing configu-
4715 rations; see boards.cfg for supported names.
4717 Note: for some board special configuration names may exist; check if
4718 additional information is available from the board vendor; for
4719 instance, the TQM823L systems are available without (standard)
4720 or with LCD support. You can select such additional "features"
4721 when choosing the configuration, i. e.
4724 - will configure for a plain TQM823L, i. e. no LCD support
4726 make TQM823L_LCD_config
4727 - will configure for a TQM823L with U-Boot console on LCD
4732 Finally, type "make all", and you should get some working U-Boot
4733 images ready for download to / installation on your system:
4735 - "u-boot.bin" is a raw binary image
4736 - "u-boot" is an image in ELF binary format
4737 - "u-boot.srec" is in Motorola S-Record format
4739 By default the build is performed locally and the objects are saved
4740 in the source directory. One of the two methods can be used to change
4741 this behavior and build U-Boot to some external directory:
4743 1. Add O= to the make command line invocations:
4745 make O=/tmp/build distclean
4746 make O=/tmp/build NAME_config
4747 make O=/tmp/build all
4749 2. Set environment variable BUILD_DIR to point to the desired location:
4751 export BUILD_DIR=/tmp/build
4756 Note that the command line "O=" setting overrides the BUILD_DIR environment
4760 Please be aware that the Makefiles assume you are using GNU make, so
4761 for instance on NetBSD you might need to use "gmake" instead of
4765 If the system board that you have is not listed, then you will need
4766 to port U-Boot to your hardware platform. To do this, follow these
4769 1. Add a new configuration option for your board to the toplevel
4770 "boards.cfg" file, using the existing entries as examples.
4771 Follow the instructions there to keep the boards in order.
4772 2. Create a new directory to hold your board specific code. Add any
4773 files you need. In your board directory, you will need at least
4774 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4775 3. Create a new configuration file "include/configs/<board>.h" for
4777 3. If you're porting U-Boot to a new CPU, then also create a new
4778 directory to hold your CPU specific code. Add any files you need.
4779 4. Run "make <board>_config" with your new name.
4780 5. Type "make", and you should get a working "u-boot.srec" file
4781 to be installed on your target system.
4782 6. Debug and solve any problems that might arise.
4783 [Of course, this last step is much harder than it sounds.]
4786 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4787 ==============================================================
4789 If you have modified U-Boot sources (for instance added a new board
4790 or support for new devices, a new CPU, etc.) you are expected to
4791 provide feedback to the other developers. The feedback normally takes
4792 the form of a "patch", i. e. a context diff against a certain (latest
4793 official or latest in the git repository) version of U-Boot sources.
4795 But before you submit such a patch, please verify that your modifi-
4796 cation did not break existing code. At least make sure that *ALL* of
4797 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4798 just run the "MAKEALL" script, which will configure and build U-Boot
4799 for ALL supported system. Be warned, this will take a while. You can
4800 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4801 environment variable to the script, i. e. to use the ELDK cross tools
4804 CROSS_COMPILE=ppc_8xx- MAKEALL
4806 or to build on a native PowerPC system you can type
4808 CROSS_COMPILE=' ' MAKEALL
4810 When using the MAKEALL script, the default behaviour is to build
4811 U-Boot in the source directory. This location can be changed by
4812 setting the BUILD_DIR environment variable. Also, for each target
4813 built, the MAKEALL script saves two log files (<target>.ERR and
4814 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4815 location can be changed by setting the MAKEALL_LOGDIR environment
4816 variable. For example:
4818 export BUILD_DIR=/tmp/build
4819 export MAKEALL_LOGDIR=/tmp/log
4820 CROSS_COMPILE=ppc_8xx- MAKEALL
4822 With the above settings build objects are saved in the /tmp/build,
4823 log files are saved in the /tmp/log and the source tree remains clean
4824 during the whole build process.
4827 See also "U-Boot Porting Guide" below.
4830 Monitor Commands - Overview:
4831 ============================
4833 go - start application at address 'addr'
4834 run - run commands in an environment variable
4835 bootm - boot application image from memory
4836 bootp - boot image via network using BootP/TFTP protocol
4837 bootz - boot zImage from memory
4838 tftpboot- boot image via network using TFTP protocol
4839 and env variables "ipaddr" and "serverip"
4840 (and eventually "gatewayip")
4841 tftpput - upload a file via network using TFTP protocol
4842 rarpboot- boot image via network using RARP/TFTP protocol
4843 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4844 loads - load S-Record file over serial line
4845 loadb - load binary file over serial line (kermit mode)
4847 mm - memory modify (auto-incrementing)
4848 nm - memory modify (constant address)
4849 mw - memory write (fill)
4851 cmp - memory compare
4852 crc32 - checksum calculation
4853 i2c - I2C sub-system
4854 sspi - SPI utility commands
4855 base - print or set address offset
4856 printenv- print environment variables
4857 setenv - set environment variables
4858 saveenv - save environment variables to persistent storage
4859 protect - enable or disable FLASH write protection
4860 erase - erase FLASH memory
4861 flinfo - print FLASH memory information
4862 nand - NAND memory operations (see doc/README.nand)
4863 bdinfo - print Board Info structure
4864 iminfo - print header information for application image
4865 coninfo - print console devices and informations
4866 ide - IDE sub-system
4867 loop - infinite loop on address range
4868 loopw - infinite write loop on address range
4869 mtest - simple RAM test
4870 icache - enable or disable instruction cache
4871 dcache - enable or disable data cache
4872 reset - Perform RESET of the CPU
4873 echo - echo args to console
4874 version - print monitor version
4875 help - print online help
4876 ? - alias for 'help'
4879 Monitor Commands - Detailed Description:
4880 ========================================
4884 For now: just type "help <command>".
4887 Environment Variables:
4888 ======================
4890 U-Boot supports user configuration using Environment Variables which
4891 can be made persistent by saving to Flash memory.
4893 Environment Variables are set using "setenv", printed using
4894 "printenv", and saved to Flash using "saveenv". Using "setenv"
4895 without a value can be used to delete a variable from the
4896 environment. As long as you don't save the environment you are
4897 working with an in-memory copy. In case the Flash area containing the
4898 environment is erased by accident, a default environment is provided.
4900 Some configuration options can be set using Environment Variables.
4902 List of environment variables (most likely not complete):
4904 baudrate - see CONFIG_BAUDRATE
4906 bootdelay - see CONFIG_BOOTDELAY
4908 bootcmd - see CONFIG_BOOTCOMMAND
4910 bootargs - Boot arguments when booting an RTOS image
4912 bootfile - Name of the image to load with TFTP
4914 bootm_low - Memory range available for image processing in the bootm
4915 command can be restricted. This variable is given as
4916 a hexadecimal number and defines lowest address allowed
4917 for use by the bootm command. See also "bootm_size"
4918 environment variable. Address defined by "bootm_low" is
4919 also the base of the initial memory mapping for the Linux
4920 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4923 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4924 This variable is given as a hexadecimal number and it
4925 defines the size of the memory region starting at base
4926 address bootm_low that is accessible by the Linux kernel
4927 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4928 as the default value if it is defined, and bootm_size is
4931 bootm_size - Memory range available for image processing in the bootm
4932 command can be restricted. This variable is given as
4933 a hexadecimal number and defines the size of the region
4934 allowed for use by the bootm command. See also "bootm_low"
4935 environment variable.
4937 updatefile - Location of the software update file on a TFTP server, used
4938 by the automatic software update feature. Please refer to
4939 documentation in doc/README.update for more details.
4941 autoload - if set to "no" (any string beginning with 'n'),
4942 "bootp" will just load perform a lookup of the
4943 configuration from the BOOTP server, but not try to
4944 load any image using TFTP
4946 autostart - if set to "yes", an image loaded using the "bootp",
4947 "rarpboot", "tftpboot" or "diskboot" commands will
4948 be automatically started (by internally calling
4951 If set to "no", a standalone image passed to the
4952 "bootm" command will be copied to the load address
4953 (and eventually uncompressed), but NOT be started.
4954 This can be used to load and uncompress arbitrary
4957 fdt_high - if set this restricts the maximum address that the
4958 flattened device tree will be copied into upon boot.
4959 For example, if you have a system with 1 GB memory
4960 at physical address 0x10000000, while Linux kernel
4961 only recognizes the first 704 MB as low memory, you
4962 may need to set fdt_high as 0x3C000000 to have the
4963 device tree blob be copied to the maximum address
4964 of the 704 MB low memory, so that Linux kernel can
4965 access it during the boot procedure.
4967 If this is set to the special value 0xFFFFFFFF then
4968 the fdt will not be copied at all on boot. For this
4969 to work it must reside in writable memory, have
4970 sufficient padding on the end of it for u-boot to
4971 add the information it needs into it, and the memory
4972 must be accessible by the kernel.
4974 fdtcontroladdr- if set this is the address of the control flattened
4975 device tree used by U-Boot when CONFIG_OF_CONTROL is
4978 i2cfast - (PPC405GP|PPC405EP only)
4979 if set to 'y' configures Linux I2C driver for fast
4980 mode (400kHZ). This environment variable is used in
4981 initialization code. So, for changes to be effective
4982 it must be saved and board must be reset.
4984 initrd_high - restrict positioning of initrd images:
4985 If this variable is not set, initrd images will be
4986 copied to the highest possible address in RAM; this
4987 is usually what you want since it allows for
4988 maximum initrd size. If for some reason you want to
4989 make sure that the initrd image is loaded below the
4990 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4991 variable to a value of "no" or "off" or "0".
4992 Alternatively, you can set it to a maximum upper
4993 address to use (U-Boot will still check that it
4994 does not overwrite the U-Boot stack and data).
4996 For instance, when you have a system with 16 MB
4997 RAM, and want to reserve 4 MB from use by Linux,
4998 you can do this by adding "mem=12M" to the value of
4999 the "bootargs" variable. However, now you must make
5000 sure that the initrd image is placed in the first
5001 12 MB as well - this can be done with
5003 setenv initrd_high 00c00000
5005 If you set initrd_high to 0xFFFFFFFF, this is an
5006 indication to U-Boot that all addresses are legal
5007 for the Linux kernel, including addresses in flash
5008 memory. In this case U-Boot will NOT COPY the
5009 ramdisk at all. This may be useful to reduce the
5010 boot time on your system, but requires that this
5011 feature is supported by your Linux kernel.
5013 ipaddr - IP address; needed for tftpboot command
5015 loadaddr - Default load address for commands like "bootp",
5016 "rarpboot", "tftpboot", "loadb" or "diskboot"
5018 loads_echo - see CONFIG_LOADS_ECHO
5020 serverip - TFTP server IP address; needed for tftpboot command
5022 bootretry - see CONFIG_BOOT_RETRY_TIME
5024 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5026 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5028 ethprime - controls which interface is used first.
5030 ethact - controls which interface is currently active.
5031 For example you can do the following
5033 => setenv ethact FEC
5034 => ping 192.168.0.1 # traffic sent on FEC
5035 => setenv ethact SCC
5036 => ping 10.0.0.1 # traffic sent on SCC
5038 ethrotate - When set to "no" U-Boot does not go through all
5039 available network interfaces.
5040 It just stays at the currently selected interface.
5042 netretry - When set to "no" each network operation will
5043 either succeed or fail without retrying.
5044 When set to "once" the network operation will
5045 fail when all the available network interfaces
5046 are tried once without success.
5047 Useful on scripts which control the retry operation
5050 npe_ucode - set load address for the NPE microcode
5052 silent_linux - If set then linux will be told to boot silently, by
5053 changing the console to be empty. If "yes" it will be
5054 made silent. If "no" it will not be made silent. If
5055 unset, then it will be made silent if the U-Boot console
5058 tftpsrcport - If this is set, the value is used for TFTP's
5061 tftpdstport - If this is set, the value is used for TFTP's UDP
5062 destination port instead of the Well Know Port 69.
5064 tftpblocksize - Block size to use for TFTP transfers; if not set,
5065 we use the TFTP server's default block size
5067 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5068 seconds, minimum value is 1000 = 1 second). Defines
5069 when a packet is considered to be lost so it has to
5070 be retransmitted. The default is 5000 = 5 seconds.
5071 Lowering this value may make downloads succeed
5072 faster in networks with high packet loss rates or
5073 with unreliable TFTP servers.
5075 vlan - When set to a value < 4095 the traffic over
5076 Ethernet is encapsulated/received over 802.1q
5079 The following image location variables contain the location of images
5080 used in booting. The "Image" column gives the role of the image and is
5081 not an environment variable name. The other columns are environment
5082 variable names. "File Name" gives the name of the file on a TFTP
5083 server, "RAM Address" gives the location in RAM the image will be
5084 loaded to, and "Flash Location" gives the image's address in NOR
5085 flash or offset in NAND flash.
5087 *Note* - these variables don't have to be defined for all boards, some
5088 boards currenlty use other variables for these purposes, and some
5089 boards use these variables for other purposes.
5091 Image File Name RAM Address Flash Location
5092 ----- --------- ----------- --------------
5093 u-boot u-boot u-boot_addr_r u-boot_addr
5094 Linux kernel bootfile kernel_addr_r kernel_addr
5095 device tree blob fdtfile fdt_addr_r fdt_addr
5096 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5098 The following environment variables may be used and automatically
5099 updated by the network boot commands ("bootp" and "rarpboot"),
5100 depending the information provided by your boot server:
5102 bootfile - see above
5103 dnsip - IP address of your Domain Name Server
5104 dnsip2 - IP address of your secondary Domain Name Server
5105 gatewayip - IP address of the Gateway (Router) to use
5106 hostname - Target hostname
5108 netmask - Subnet Mask
5109 rootpath - Pathname of the root filesystem on the NFS server
5110 serverip - see above
5113 There are two special Environment Variables:
5115 serial# - contains hardware identification information such
5116 as type string and/or serial number
5117 ethaddr - Ethernet address
5119 These variables can be set only once (usually during manufacturing of
5120 the board). U-Boot refuses to delete or overwrite these variables
5121 once they have been set once.
5124 Further special Environment Variables:
5126 ver - Contains the U-Boot version string as printed
5127 with the "version" command. This variable is
5128 readonly (see CONFIG_VERSION_VARIABLE).
5131 Please note that changes to some configuration parameters may take
5132 only effect after the next boot (yes, that's just like Windoze :-).
5135 Callback functions for environment variables:
5136 ---------------------------------------------
5138 For some environment variables, the behavior of u-boot needs to change
5139 when their values are changed. This functionailty allows functions to
5140 be associated with arbitrary variables. On creation, overwrite, or
5141 deletion, the callback will provide the opportunity for some side
5142 effect to happen or for the change to be rejected.
5144 The callbacks are named and associated with a function using the
5145 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5147 These callbacks are associated with variables in one of two ways. The
5148 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5149 in the board configuration to a string that defines a list of
5150 associations. The list must be in the following format:
5152 entry = variable_name[:callback_name]
5155 If the callback name is not specified, then the callback is deleted.
5156 Spaces are also allowed anywhere in the list.
5158 Callbacks can also be associated by defining the ".callbacks" variable
5159 with the same list format above. Any association in ".callbacks" will
5160 override any association in the static list. You can define
5161 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5162 ".callbacks" envirnoment variable in the default or embedded environment.
5165 Command Line Parsing:
5166 =====================
5168 There are two different command line parsers available with U-Boot:
5169 the old "simple" one, and the much more powerful "hush" shell:
5171 Old, simple command line parser:
5172 --------------------------------
5174 - supports environment variables (through setenv / saveenv commands)
5175 - several commands on one line, separated by ';'
5176 - variable substitution using "... ${name} ..." syntax
5177 - special characters ('$', ';') can be escaped by prefixing with '\',
5179 setenv bootcmd bootm \${address}
5180 - You can also escape text by enclosing in single apostrophes, for example:
5181 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5186 - similar to Bourne shell, with control structures like
5187 if...then...else...fi, for...do...done; while...do...done,
5188 until...do...done, ...
5189 - supports environment ("global") variables (through setenv / saveenv
5190 commands) and local shell variables (through standard shell syntax
5191 "name=value"); only environment variables can be used with "run"
5197 (1) If a command line (or an environment variable executed by a "run"
5198 command) contains several commands separated by semicolon, and
5199 one of these commands fails, then the remaining commands will be
5202 (2) If you execute several variables with one call to run (i. e.
5203 calling run with a list of variables as arguments), any failing
5204 command will cause "run" to terminate, i. e. the remaining
5205 variables are not executed.
5207 Note for Redundant Ethernet Interfaces:
5208 =======================================
5210 Some boards come with redundant Ethernet interfaces; U-Boot supports
5211 such configurations and is capable of automatic selection of a
5212 "working" interface when needed. MAC assignment works as follows:
5214 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5215 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5216 "eth1addr" (=>eth1), "eth2addr", ...
5218 If the network interface stores some valid MAC address (for instance
5219 in SROM), this is used as default address if there is NO correspon-
5220 ding setting in the environment; if the corresponding environment
5221 variable is set, this overrides the settings in the card; that means:
5223 o If the SROM has a valid MAC address, and there is no address in the
5224 environment, the SROM's address is used.
5226 o If there is no valid address in the SROM, and a definition in the
5227 environment exists, then the value from the environment variable is
5230 o If both the SROM and the environment contain a MAC address, and
5231 both addresses are the same, this MAC address is used.
5233 o If both the SROM and the environment contain a MAC address, and the
5234 addresses differ, the value from the environment is used and a
5237 o If neither SROM nor the environment contain a MAC address, an error
5240 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5241 will be programmed into hardware as part of the initialization process. This
5242 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5243 The naming convention is as follows:
5244 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5249 U-Boot is capable of booting (and performing other auxiliary operations on)
5250 images in two formats:
5252 New uImage format (FIT)
5253 -----------------------
5255 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5256 to Flattened Device Tree). It allows the use of images with multiple
5257 components (several kernels, ramdisks, etc.), with contents protected by
5258 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5264 Old image format is based on binary files which can be basically anything,
5265 preceded by a special header; see the definitions in include/image.h for
5266 details; basically, the header defines the following image properties:
5268 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5269 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5270 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5271 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5273 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5274 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5275 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5276 * Compression Type (uncompressed, gzip, bzip2)
5282 The header is marked by a special Magic Number, and both the header
5283 and the data portions of the image are secured against corruption by
5290 Although U-Boot should support any OS or standalone application
5291 easily, the main focus has always been on Linux during the design of
5294 U-Boot includes many features that so far have been part of some
5295 special "boot loader" code within the Linux kernel. Also, any
5296 "initrd" images to be used are no longer part of one big Linux image;
5297 instead, kernel and "initrd" are separate images. This implementation
5298 serves several purposes:
5300 - the same features can be used for other OS or standalone
5301 applications (for instance: using compressed images to reduce the
5302 Flash memory footprint)
5304 - it becomes much easier to port new Linux kernel versions because
5305 lots of low-level, hardware dependent stuff are done by U-Boot
5307 - the same Linux kernel image can now be used with different "initrd"
5308 images; of course this also means that different kernel images can
5309 be run with the same "initrd". This makes testing easier (you don't
5310 have to build a new "zImage.initrd" Linux image when you just
5311 change a file in your "initrd"). Also, a field-upgrade of the
5312 software is easier now.
5318 Porting Linux to U-Boot based systems:
5319 ---------------------------------------
5321 U-Boot cannot save you from doing all the necessary modifications to
5322 configure the Linux device drivers for use with your target hardware
5323 (no, we don't intend to provide a full virtual machine interface to
5326 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5328 Just make sure your machine specific header file (for instance
5329 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5330 Information structure as we define in include/asm-<arch>/u-boot.h,
5331 and make sure that your definition of IMAP_ADDR uses the same value
5332 as your U-Boot configuration in CONFIG_SYS_IMMR.
5334 Note that U-Boot now has a driver model, a unified model for drivers.
5335 If you are adding a new driver, plumb it into driver model. If there
5336 is no uclass available, you are encouraged to create one. See
5340 Configuring the Linux kernel:
5341 -----------------------------
5343 No specific requirements for U-Boot. Make sure you have some root
5344 device (initial ramdisk, NFS) for your target system.
5347 Building a Linux Image:
5348 -----------------------
5350 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5351 not used. If you use recent kernel source, a new build target
5352 "uImage" will exist which automatically builds an image usable by
5353 U-Boot. Most older kernels also have support for a "pImage" target,
5354 which was introduced for our predecessor project PPCBoot and uses a
5355 100% compatible format.
5364 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5365 encapsulate a compressed Linux kernel image with header information,
5366 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5368 * build a standard "vmlinux" kernel image (in ELF binary format):
5370 * convert the kernel into a raw binary image:
5372 ${CROSS_COMPILE}-objcopy -O binary \
5373 -R .note -R .comment \
5374 -S vmlinux linux.bin
5376 * compress the binary image:
5380 * package compressed binary image for U-Boot:
5382 mkimage -A ppc -O linux -T kernel -C gzip \
5383 -a 0 -e 0 -n "Linux Kernel Image" \
5384 -d linux.bin.gz uImage
5387 The "mkimage" tool can also be used to create ramdisk images for use
5388 with U-Boot, either separated from the Linux kernel image, or
5389 combined into one file. "mkimage" encapsulates the images with a 64
5390 byte header containing information about target architecture,
5391 operating system, image type, compression method, entry points, time
5392 stamp, CRC32 checksums, etc.
5394 "mkimage" can be called in two ways: to verify existing images and
5395 print the header information, or to build new images.
5397 In the first form (with "-l" option) mkimage lists the information
5398 contained in the header of an existing U-Boot image; this includes
5399 checksum verification:
5401 tools/mkimage -l image
5402 -l ==> list image header information
5404 The second form (with "-d" option) is used to build a U-Boot image
5405 from a "data file" which is used as image payload:
5407 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5408 -n name -d data_file image
5409 -A ==> set architecture to 'arch'
5410 -O ==> set operating system to 'os'
5411 -T ==> set image type to 'type'
5412 -C ==> set compression type 'comp'
5413 -a ==> set load address to 'addr' (hex)
5414 -e ==> set entry point to 'ep' (hex)
5415 -n ==> set image name to 'name'
5416 -d ==> use image data from 'datafile'
5418 Right now, all Linux kernels for PowerPC systems use the same load
5419 address (0x00000000), but the entry point address depends on the
5422 - 2.2.x kernels have the entry point at 0x0000000C,
5423 - 2.3.x and later kernels have the entry point at 0x00000000.
5425 So a typical call to build a U-Boot image would read:
5427 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5428 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5429 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5430 > examples/uImage.TQM850L
5431 Image Name: 2.4.4 kernel for TQM850L
5432 Created: Wed Jul 19 02:34:59 2000
5433 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5434 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5435 Load Address: 0x00000000
5436 Entry Point: 0x00000000
5438 To verify the contents of the image (or check for corruption):
5440 -> tools/mkimage -l examples/uImage.TQM850L
5441 Image Name: 2.4.4 kernel for TQM850L
5442 Created: Wed Jul 19 02:34:59 2000
5443 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5444 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5445 Load Address: 0x00000000
5446 Entry Point: 0x00000000
5448 NOTE: for embedded systems where boot time is critical you can trade
5449 speed for memory and install an UNCOMPRESSED image instead: this
5450 needs more space in Flash, but boots much faster since it does not
5451 need to be uncompressed:
5453 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5454 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5455 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5456 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5457 > examples/uImage.TQM850L-uncompressed
5458 Image Name: 2.4.4 kernel for TQM850L
5459 Created: Wed Jul 19 02:34:59 2000
5460 Image Type: PowerPC Linux Kernel Image (uncompressed)
5461 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5462 Load Address: 0x00000000
5463 Entry Point: 0x00000000
5466 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5467 when your kernel is intended to use an initial ramdisk:
5469 -> tools/mkimage -n 'Simple Ramdisk Image' \
5470 > -A ppc -O linux -T ramdisk -C gzip \
5471 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5472 Image Name: Simple Ramdisk Image
5473 Created: Wed Jan 12 14:01:50 2000
5474 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5475 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5476 Load Address: 0x00000000
5477 Entry Point: 0x00000000
5479 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5480 option performs the converse operation of the mkimage's second form (the "-d"
5481 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5484 tools/dumpimage -i image -p position data_file
5485 -i ==> extract from the 'image' a specific 'data_file', \
5486 indexed by 'position'
5489 Installing a Linux Image:
5490 -------------------------
5492 To downloading a U-Boot image over the serial (console) interface,
5493 you must convert the image to S-Record format:
5495 objcopy -I binary -O srec examples/image examples/image.srec
5497 The 'objcopy' does not understand the information in the U-Boot
5498 image header, so the resulting S-Record file will be relative to
5499 address 0x00000000. To load it to a given address, you need to
5500 specify the target address as 'offset' parameter with the 'loads'
5503 Example: install the image to address 0x40100000 (which on the
5504 TQM8xxL is in the first Flash bank):
5506 => erase 40100000 401FFFFF
5512 ## Ready for S-Record download ...
5513 ~>examples/image.srec
5514 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5516 15989 15990 15991 15992
5517 [file transfer complete]
5519 ## Start Addr = 0x00000000
5522 You can check the success of the download using the 'iminfo' command;
5523 this includes a checksum verification so you can be sure no data
5524 corruption happened:
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
5540 The "bootm" command is used to boot an application that is stored in
5541 memory (RAM or Flash). In case of a Linux kernel image, the contents
5542 of the "bootargs" environment variable is passed to the kernel as
5543 parameters. You can check and modify this variable using the
5544 "printenv" and "setenv" commands:
5547 => printenv bootargs
5548 bootargs=root=/dev/ram
5550 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5552 => printenv bootargs
5553 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5556 ## Booting Linux kernel at 40020000 ...
5557 Image Name: 2.2.13 for NFS on TQM850L
5558 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5559 Data Size: 381681 Bytes = 372 kB = 0 MB
5560 Load Address: 00000000
5561 Entry Point: 0000000c
5562 Verifying Checksum ... OK
5563 Uncompressing Kernel Image ... OK
5564 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
5565 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5566 time_init: decrementer frequency = 187500000/60
5567 Calibrating delay loop... 49.77 BogoMIPS
5568 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5571 If you want to boot a Linux kernel with initial RAM disk, you pass
5572 the memory addresses of both the kernel and the initrd image (PPBCOOT
5573 format!) to the "bootm" command:
5575 => imi 40100000 40200000
5577 ## Checking Image at 40100000 ...
5578 Image Name: 2.2.13 for initrd on TQM850L
5579 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5580 Data Size: 335725 Bytes = 327 kB = 0 MB
5581 Load Address: 00000000
5582 Entry Point: 0000000c
5583 Verifying Checksum ... OK
5585 ## Checking Image at 40200000 ...
5586 Image Name: Simple Ramdisk Image
5587 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5588 Data Size: 566530 Bytes = 553 kB = 0 MB
5589 Load Address: 00000000
5590 Entry Point: 00000000
5591 Verifying Checksum ... OK
5593 => bootm 40100000 40200000
5594 ## Booting Linux kernel at 40100000 ...
5595 Image Name: 2.2.13 for initrd on TQM850L
5596 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5597 Data Size: 335725 Bytes = 327 kB = 0 MB
5598 Load Address: 00000000
5599 Entry Point: 0000000c
5600 Verifying Checksum ... OK
5601 Uncompressing Kernel Image ... OK
5602 ## Loading RAMDisk Image at 40200000 ...
5603 Image Name: Simple Ramdisk Image
5604 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5605 Data Size: 566530 Bytes = 553 kB = 0 MB
5606 Load Address: 00000000
5607 Entry Point: 00000000
5608 Verifying Checksum ... OK
5609 Loading Ramdisk ... OK
5610 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
5611 Boot arguments: root=/dev/ram
5612 time_init: decrementer frequency = 187500000/60
5613 Calibrating delay loop... 49.77 BogoMIPS
5615 RAMDISK: Compressed image found at block 0
5616 VFS: Mounted root (ext2 filesystem).
5620 Boot Linux and pass a flat device tree:
5623 First, U-Boot must be compiled with the appropriate defines. See the section
5624 titled "Linux Kernel Interface" above for a more in depth explanation. The
5625 following is an example of how to start a kernel and pass an updated
5631 oft=oftrees/mpc8540ads.dtb
5632 => tftp $oftaddr $oft
5633 Speed: 1000, full duplex
5635 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5636 Filename 'oftrees/mpc8540ads.dtb'.
5637 Load address: 0x300000
5640 Bytes transferred = 4106 (100a hex)
5641 => tftp $loadaddr $bootfile
5642 Speed: 1000, full duplex
5644 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5646 Load address: 0x200000
5647 Loading:############
5649 Bytes transferred = 1029407 (fb51f hex)
5654 => bootm $loadaddr - $oftaddr
5655 ## Booting image at 00200000 ...
5656 Image Name: Linux-2.6.17-dirty
5657 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5658 Data Size: 1029343 Bytes = 1005.2 kB
5659 Load Address: 00000000
5660 Entry Point: 00000000
5661 Verifying Checksum ... OK
5662 Uncompressing Kernel Image ... OK
5663 Booting using flat device tree at 0x300000
5664 Using MPC85xx ADS machine description
5665 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5669 More About U-Boot Image Types:
5670 ------------------------------
5672 U-Boot supports the following image types:
5674 "Standalone Programs" are directly runnable in the environment
5675 provided by U-Boot; it is expected that (if they behave
5676 well) you can continue to work in U-Boot after return from
5677 the Standalone Program.
5678 "OS Kernel Images" are usually images of some Embedded OS which
5679 will take over control completely. Usually these programs
5680 will install their own set of exception handlers, device
5681 drivers, set up the MMU, etc. - this means, that you cannot
5682 expect to re-enter U-Boot except by resetting the CPU.
5683 "RAMDisk Images" are more or less just data blocks, and their
5684 parameters (address, size) are passed to an OS kernel that is
5686 "Multi-File Images" contain several images, typically an OS
5687 (Linux) kernel image and one or more data images like
5688 RAMDisks. This construct is useful for instance when you want
5689 to boot over the network using BOOTP etc., where the boot
5690 server provides just a single image file, but you want to get
5691 for instance an OS kernel and a RAMDisk image.
5693 "Multi-File Images" start with a list of image sizes, each
5694 image size (in bytes) specified by an "uint32_t" in network
5695 byte order. This list is terminated by an "(uint32_t)0".
5696 Immediately after the terminating 0 follow the images, one by
5697 one, all aligned on "uint32_t" boundaries (size rounded up to
5698 a multiple of 4 bytes).
5700 "Firmware Images" are binary images containing firmware (like
5701 U-Boot or FPGA images) which usually will be programmed to
5704 "Script files" are command sequences that will be executed by
5705 U-Boot's command interpreter; this feature is especially
5706 useful when you configure U-Boot to use a real shell (hush)
5707 as command interpreter.
5709 Booting the Linux zImage:
5710 -------------------------
5712 On some platforms, it's possible to boot Linux zImage. This is done
5713 using the "bootz" command. The syntax of "bootz" command is the same
5714 as the syntax of "bootm" command.
5716 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5717 kernel with raw initrd images. The syntax is slightly different, the
5718 address of the initrd must be augmented by it's size, in the following
5719 format: "<initrd addres>:<initrd size>".
5725 One of the features of U-Boot is that you can dynamically load and
5726 run "standalone" applications, which can use some resources of
5727 U-Boot like console I/O functions or interrupt services.
5729 Two simple examples are included with the sources:
5734 'examples/hello_world.c' contains a small "Hello World" Demo
5735 application; it is automatically compiled when you build U-Boot.
5736 It's configured to run at address 0x00040004, so you can play with it
5740 ## Ready for S-Record download ...
5741 ~>examples/hello_world.srec
5742 1 2 3 4 5 6 7 8 9 10 11 ...
5743 [file transfer complete]
5745 ## Start Addr = 0x00040004
5747 => go 40004 Hello World! This is a test.
5748 ## Starting application at 0x00040004 ...
5759 Hit any key to exit ...
5761 ## Application terminated, rc = 0x0
5763 Another example, which demonstrates how to register a CPM interrupt
5764 handler with the U-Boot code, can be found in 'examples/timer.c'.
5765 Here, a CPM timer is set up to generate an interrupt every second.
5766 The interrupt service routine is trivial, just printing a '.'
5767 character, but this is just a demo program. The application can be
5768 controlled by the following keys:
5770 ? - print current values og the CPM Timer registers
5771 b - enable interrupts and start timer
5772 e - stop timer and disable interrupts
5773 q - quit application
5776 ## Ready for S-Record download ...
5777 ~>examples/timer.srec
5778 1 2 3 4 5 6 7 8 9 10 11 ...
5779 [file transfer complete]
5781 ## Start Addr = 0x00040004
5784 ## Starting application at 0x00040004 ...
5787 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5790 [q, b, e, ?] Set interval 1000000 us
5793 [q, b, e, ?] ........
5794 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5797 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5800 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5803 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5805 [q, b, e, ?] ...Stopping timer
5807 [q, b, e, ?] ## Application terminated, rc = 0x0
5813 Over time, many people have reported problems when trying to use the
5814 "minicom" terminal emulation program for serial download. I (wd)
5815 consider minicom to be broken, and recommend not to use it. Under
5816 Unix, I recommend to use C-Kermit for general purpose use (and
5817 especially for kermit binary protocol download ("loadb" command), and
5818 use "cu" for S-Record download ("loads" command). See
5819 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5820 for help with kermit.
5823 Nevertheless, if you absolutely want to use it try adding this
5824 configuration to your "File transfer protocols" section:
5826 Name Program Name U/D FullScr IO-Red. Multi
5827 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5828 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5834 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5835 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5837 Building requires a cross environment; it is known to work on
5838 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5839 need gmake since the Makefiles are not compatible with BSD make).
5840 Note that the cross-powerpc package does not install include files;
5841 attempting to build U-Boot will fail because <machine/ansi.h> is
5842 missing. This file has to be installed and patched manually:
5844 # cd /usr/pkg/cross/powerpc-netbsd/include
5846 # ln -s powerpc machine
5847 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5848 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5850 Native builds *don't* work due to incompatibilities between native
5851 and U-Boot include files.
5853 Booting assumes that (the first part of) the image booted is a
5854 stage-2 loader which in turn loads and then invokes the kernel
5855 proper. Loader sources will eventually appear in the NetBSD source
5856 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5857 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5860 Implementation Internals:
5861 =========================
5863 The following is not intended to be a complete description of every
5864 implementation detail. However, it should help to understand the
5865 inner workings of U-Boot and make it easier to port it to custom
5869 Initial Stack, Global Data:
5870 ---------------------------
5872 The implementation of U-Boot is complicated by the fact that U-Boot
5873 starts running out of ROM (flash memory), usually without access to
5874 system RAM (because the memory controller is not initialized yet).
5875 This means that we don't have writable Data or BSS segments, and BSS
5876 is not initialized as zero. To be able to get a C environment working
5877 at all, we have to allocate at least a minimal stack. Implementation
5878 options for this are defined and restricted by the CPU used: Some CPU
5879 models provide on-chip memory (like the IMMR area on MPC8xx and
5880 MPC826x processors), on others (parts of) the data cache can be
5881 locked as (mis-) used as memory, etc.
5883 Chris Hallinan posted a good summary of these issues to the
5884 U-Boot mailing list:
5886 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5887 From: "Chris Hallinan" <clh@net1plus.com>
5888 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5891 Correct me if I'm wrong, folks, but the way I understand it
5892 is this: Using DCACHE as initial RAM for Stack, etc, does not
5893 require any physical RAM backing up the cache. The cleverness
5894 is that the cache is being used as a temporary supply of
5895 necessary storage before the SDRAM controller is setup. It's
5896 beyond the scope of this list to explain the details, but you
5897 can see how this works by studying the cache architecture and
5898 operation in the architecture and processor-specific manuals.
5900 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5901 is another option for the system designer to use as an
5902 initial stack/RAM area prior to SDRAM being available. Either
5903 option should work for you. Using CS 4 should be fine if your
5904 board designers haven't used it for something that would
5905 cause you grief during the initial boot! It is frequently not
5908 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5909 with your processor/board/system design. The default value
5910 you will find in any recent u-boot distribution in
5911 walnut.h should work for you. I'd set it to a value larger
5912 than your SDRAM module. If you have a 64MB SDRAM module, set
5913 it above 400_0000. Just make sure your board has no resources
5914 that are supposed to respond to that address! That code in
5915 start.S has been around a while and should work as is when
5916 you get the config right.
5921 It is essential to remember this, since it has some impact on the C
5922 code for the initialization procedures:
5924 * Initialized global data (data segment) is read-only. Do not attempt
5927 * Do not use any uninitialized global data (or implicitely initialized
5928 as zero data - BSS segment) at all - this is undefined, initiali-
5929 zation is performed later (when relocating to RAM).
5931 * Stack space is very limited. Avoid big data buffers or things like
5934 Having only the stack as writable memory limits means we cannot use
5935 normal global data to share information beween the code. But it
5936 turned out that the implementation of U-Boot can be greatly
5937 simplified by making a global data structure (gd_t) available to all
5938 functions. We could pass a pointer to this data as argument to _all_
5939 functions, but this would bloat the code. Instead we use a feature of
5940 the GCC compiler (Global Register Variables) to share the data: we
5941 place a pointer (gd) to the global data into a register which we
5942 reserve for this purpose.
5944 When choosing a register for such a purpose we are restricted by the
5945 relevant (E)ABI specifications for the current architecture, and by
5946 GCC's implementation.
5948 For PowerPC, the following registers have specific use:
5950 R2: reserved for system use
5951 R3-R4: parameter passing and return values
5952 R5-R10: parameter passing
5953 R13: small data area pointer
5957 (U-Boot also uses R12 as internal GOT pointer. r12
5958 is a volatile register so r12 needs to be reset when
5959 going back and forth between asm and C)
5961 ==> U-Boot will use R2 to hold a pointer to the global data
5963 Note: on PPC, we could use a static initializer (since the
5964 address of the global data structure is known at compile time),
5965 but it turned out that reserving a register results in somewhat
5966 smaller code - although the code savings are not that big (on
5967 average for all boards 752 bytes for the whole U-Boot image,
5968 624 text + 127 data).
5970 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5971 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5973 ==> U-Boot will use P3 to hold a pointer to the global data
5975 On ARM, the following registers are used:
5977 R0: function argument word/integer result
5978 R1-R3: function argument word
5979 R9: platform specific
5980 R10: stack limit (used only if stack checking is enabled)
5981 R11: argument (frame) pointer
5982 R12: temporary workspace
5985 R15: program counter
5987 ==> U-Boot will use R9 to hold a pointer to the global data
5989 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5991 On Nios II, the ABI is documented here:
5992 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5994 ==> U-Boot will use gp to hold a pointer to the global data
5996 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5997 to access small data sections, so gp is free.
5999 On NDS32, the following registers are used:
6001 R0-R1: argument/return
6003 R15: temporary register for assembler
6004 R16: trampoline register
6005 R28: frame pointer (FP)
6006 R29: global pointer (GP)
6007 R30: link register (LP)
6008 R31: stack pointer (SP)
6009 PC: program counter (PC)
6011 ==> U-Boot will use R10 to hold a pointer to the global data
6013 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6014 or current versions of GCC may "optimize" the code too much.
6019 U-Boot runs in system state and uses physical addresses, i.e. the
6020 MMU is not used either for address mapping nor for memory protection.
6022 The available memory is mapped to fixed addresses using the memory
6023 controller. In this process, a contiguous block is formed for each
6024 memory type (Flash, SDRAM, SRAM), even when it consists of several
6025 physical memory banks.
6027 U-Boot is installed in the first 128 kB of the first Flash bank (on
6028 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6029 booting and sizing and initializing DRAM, the code relocates itself
6030 to the upper end of DRAM. Immediately below the U-Boot code some
6031 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6032 configuration setting]. Below that, a structure with global Board
6033 Info data is placed, followed by the stack (growing downward).
6035 Additionally, some exception handler code is copied to the low 8 kB
6036 of DRAM (0x00000000 ... 0x00001FFF).
6038 So a typical memory configuration with 16 MB of DRAM could look like
6041 0x0000 0000 Exception Vector code
6044 0x0000 2000 Free for Application Use
6050 0x00FB FF20 Monitor Stack (Growing downward)
6051 0x00FB FFAC Board Info Data and permanent copy of global data
6052 0x00FC 0000 Malloc Arena
6055 0x00FE 0000 RAM Copy of Monitor Code
6056 ... eventually: LCD or video framebuffer
6057 ... eventually: pRAM (Protected RAM - unchanged by reset)
6058 0x00FF FFFF [End of RAM]
6061 System Initialization:
6062 ----------------------
6064 In the reset configuration, U-Boot starts at the reset entry point
6065 (on most PowerPC systems at address 0x00000100). Because of the reset
6066 configuration for CS0# this is a mirror of the onboard Flash memory.
6067 To be able to re-map memory U-Boot then jumps to its link address.
6068 To be able to implement the initialization code in C, a (small!)
6069 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6070 which provide such a feature like MPC8xx or MPC8260), or in a locked
6071 part of the data cache. After that, U-Boot initializes the CPU core,
6072 the caches and the SIU.
6074 Next, all (potentially) available memory banks are mapped using a
6075 preliminary mapping. For example, we put them on 512 MB boundaries
6076 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6077 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6078 programmed for SDRAM access. Using the temporary configuration, a
6079 simple memory test is run that determines the size of the SDRAM
6082 When there is more than one SDRAM bank, and the banks are of
6083 different size, the largest is mapped first. For equal size, the first
6084 bank (CS2#) is mapped first. The first mapping is always for address
6085 0x00000000, with any additional banks following immediately to create
6086 contiguous memory starting from 0.
6088 Then, the monitor installs itself at the upper end of the SDRAM area
6089 and allocates memory for use by malloc() and for the global Board
6090 Info data; also, the exception vector code is copied to the low RAM
6091 pages, and the final stack is set up.
6093 Only after this relocation will you have a "normal" C environment;
6094 until that you are restricted in several ways, mostly because you are
6095 running from ROM, and because the code will have to be relocated to a
6099 U-Boot Porting Guide:
6100 ----------------------
6102 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6106 int main(int argc, char *argv[])
6108 sighandler_t no_more_time;
6110 signal(SIGALRM, no_more_time);
6111 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6113 if (available_money > available_manpower) {
6114 Pay consultant to port U-Boot;
6118 Download latest U-Boot source;
6120 Subscribe to u-boot mailing list;
6123 email("Hi, I am new to U-Boot, how do I get started?");
6126 Read the README file in the top level directory;
6127 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6128 Read applicable doc/*.README;
6129 Read the source, Luke;
6130 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6133 if (available_money > toLocalCurrency ($2500))
6136 Add a lot of aggravation and time;
6138 if (a similar board exists) { /* hopefully... */
6139 cp -a board/<similar> board/<myboard>
6140 cp include/configs/<similar>.h include/configs/<myboard>.h
6142 Create your own board support subdirectory;
6143 Create your own board include/configs/<myboard>.h file;
6145 Edit new board/<myboard> files
6146 Edit new include/configs/<myboard>.h
6151 Add / modify source code;
6155 email("Hi, I am having problems...");
6157 Send patch file to the U-Boot email list;
6158 if (reasonable critiques)
6159 Incorporate improvements from email list code review;
6161 Defend code as written;
6167 void no_more_time (int sig)
6176 All contributions to U-Boot should conform to the Linux kernel
6177 coding style; see the file "Documentation/CodingStyle" and the script
6178 "scripts/Lindent" in your Linux kernel source directory.
6180 Source files originating from a different project (for example the
6181 MTD subsystem) are generally exempt from these guidelines and are not
6182 reformated to ease subsequent migration to newer versions of those
6185 Please note that U-Boot is implemented in C (and to some small parts in
6186 Assembler); no C++ is used, so please do not use C++ style comments (//)
6189 Please also stick to the following formatting rules:
6190 - remove any trailing white space
6191 - use TAB characters for indentation and vertical alignment, not spaces
6192 - make sure NOT to use DOS '\r\n' line feeds
6193 - do not add more than 2 consecutive empty lines to source files
6194 - do not add trailing empty lines to source files
6196 Submissions which do not conform to the standards may be returned
6197 with a request to reformat the changes.
6203 Since the number of patches for U-Boot is growing, we need to
6204 establish some rules. Submissions which do not conform to these rules
6205 may be rejected, even when they contain important and valuable stuff.
6207 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6209 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6210 see http://lists.denx.de/mailman/listinfo/u-boot
6212 When you send a patch, please include the following information with
6215 * For bug fixes: a description of the bug and how your patch fixes
6216 this bug. Please try to include a way of demonstrating that the
6217 patch actually fixes something.
6219 * For new features: a description of the feature and your
6222 * A CHANGELOG entry as plaintext (separate from the patch)
6224 * For major contributions, your entry to the CREDITS file
6226 * When you add support for a new board, don't forget to add a
6227 maintainer e-mail address to the boards.cfg file, too.
6229 * If your patch adds new configuration options, don't forget to
6230 document these in the README file.
6232 * The patch itself. If you are using git (which is *strongly*
6233 recommended) you can easily generate the patch using the
6234 "git format-patch". If you then use "git send-email" to send it to
6235 the U-Boot mailing list, you will avoid most of the common problems
6236 with some other mail clients.
6238 If you cannot use git, use "diff -purN OLD NEW". If your version of
6239 diff does not support these options, then get the latest version of
6242 The current directory when running this command shall be the parent
6243 directory of the U-Boot source tree (i. e. please make sure that
6244 your patch includes sufficient directory information for the
6247 We prefer patches as plain text. MIME attachments are discouraged,
6248 and compressed attachments must not be used.
6250 * If one logical set of modifications affects or creates several
6251 files, all these changes shall be submitted in a SINGLE patch file.
6253 * Changesets that contain different, unrelated modifications shall be
6254 submitted as SEPARATE patches, one patch per changeset.
6259 * Before sending the patch, run the MAKEALL script on your patched
6260 source tree and make sure that no errors or warnings are reported
6261 for any of the boards.
6263 * Keep your modifications to the necessary minimum: A patch
6264 containing several unrelated changes or arbitrary reformats will be
6265 returned with a request to re-formatting / split it.
6267 * If you modify existing code, make sure that your new code does not
6268 add to the memory footprint of the code ;-) Small is beautiful!
6269 When adding new features, these should compile conditionally only
6270 (using #ifdef), and the resulting code with the new feature
6271 disabled must not need more memory than the old code without your
6274 * Remember that there is a size limit of 100 kB per message on the
6275 u-boot mailing list. Bigger patches will be moderated. If they are
6276 reasonable and not too big, they will be acknowledged. But patches
6277 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob