2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
186 /mpc5xx Files specific to Freescale MPC5xx CPUs
187 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
188 /mpc8xx Files specific to Freescale MPC8xx CPUs
189 /mpc824x Files specific to Freescale MPC824x CPUs
190 /mpc8260 Files specific to Freescale MPC8260 CPUs
191 /mpc85xx Files specific to Freescale MPC85xx CPUs
192 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
193 /lib Architecture specific library files
194 /sh Files generic to SH architecture
195 /cpu CPU specific files
196 /sh2 Files specific to sh2 CPUs
197 /sh3 Files specific to sh3 CPUs
198 /sh4 Files specific to sh4 CPUs
199 /lib Architecture specific library files
200 /sparc Files generic to SPARC architecture
201 /cpu CPU specific files
202 /leon2 Files specific to Gaisler LEON2 SPARC CPU
203 /leon3 Files specific to Gaisler LEON3 SPARC CPU
204 /lib Architecture specific library files
205 /x86 Files generic to x86 architecture
206 /cpu CPU specific files
207 /lib Architecture specific library files
208 /api Machine/arch independent API for external apps
209 /board Board dependent files
210 /common Misc architecture independent functions
211 /disk Code for disk drive partition handling
212 /doc Documentation (don't expect too much)
213 /drivers Commonly used device drivers
214 /dts Contains Makefile for building internal U-Boot fdt.
215 /examples Example code for standalone applications, etc.
216 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
217 /include Header Files
218 /lib Files generic to all architectures
219 /libfdt Library files to support flattened device trees
220 /lzma Library files to support LZMA decompression
221 /lzo Library files to support LZO decompression
223 /post Power On Self Test
224 /spl Secondary Program Loader framework
225 /tools Tools to build S-Record or U-Boot images, etc.
227 Software Configuration:
228 =======================
230 Configuration is usually done using C preprocessor defines; the
231 rationale behind that is to avoid dead code whenever possible.
233 There are two classes of configuration variables:
235 * Configuration _OPTIONS_:
236 These are selectable by the user and have names beginning with
239 * Configuration _SETTINGS_:
240 These depend on the hardware etc. and should not be meddled with if
241 you don't know what you're doing; they have names beginning with
244 Later we will add a configuration tool - probably similar to or even
245 identical to what's used for the Linux kernel. Right now, we have to
246 do the configuration by hand, which means creating some symbolic
247 links and editing some configuration files. We use the TQM8xxL boards
251 Selection of Processor Architecture and Board Type:
252 ---------------------------------------------------
254 For all supported boards there are ready-to-use default
255 configurations available; just type "make <board_name>_config".
257 Example: For a TQM823L module type:
262 For the Cogent platform, you need to specify the CPU type as well;
263 e.g. "make cogent_mpc8xx_config". And also configure the cogent
264 directory according to the instructions in cogent/README.
270 U-Boot can be built natively to run on a Linux host using the 'sandbox'
271 board. This allows feature development which is not board- or architecture-
272 specific to be undertaken on a native platform. The sandbox is also used to
273 run some of U-Boot's tests.
275 See board/sandbox/sandbox/README.sandbox for more details.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Marvell Family Member
325 CONFIG_SYS_MVFS - define it if you want to enable
326 multiple fs option at one time
327 for marvell soc family
329 - MPC824X Family Member (if CONFIG_MPC824X is defined)
330 Define exactly one of
331 CONFIG_MPC8240, CONFIG_MPC8245
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_PPC_E500_DEBUG_TLB
381 Enables a temporary TLB entry to be used during boot to work
382 around limitations in e500v1 and e500v2 external debugger
383 support. This reduces the portions of the boot code where
384 breakpoints and single stepping do not work. The value of this
385 symbol should be set to the TLB1 entry to be used for this
388 CONFIG_SYS_FSL_ERRATUM_A004510
390 Enables a workaround for erratum A004510. If set,
391 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
394 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
397 Defines one or two SoC revisions (low 8 bits of SVR)
398 for which the A004510 workaround should be applied.
400 The rest of SVR is either not relevant to the decision
401 of whether the erratum is present (e.g. p2040 versus
402 p2041) or is implied by the build target, which controls
403 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
405 See Freescale App Note 4493 for more information about
408 CONFIG_A003399_NOR_WORKAROUND
409 Enables a workaround for IFC erratum A003399. It is only
410 requred during NOR boot.
412 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
414 This is the value to write into CCSR offset 0x18600
415 according to the A004510 workaround.
417 CONFIG_SYS_FSL_DSP_DDR_ADDR
418 This value denotes start offset of DDR memory which is
419 connected exclusively to the DSP cores.
421 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
422 This value denotes start offset of M2 memory
423 which is directly connected to the DSP core.
425 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
426 This value denotes start offset of M3 memory which is directly
427 connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430 This value denotes start offset of DSP CCSR space.
432 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
433 Single Source Clock is clocking mode present in some of FSL SoC's.
434 In this mode, a single differential clock is used to supply
435 clocks to the sysclock, ddrclock and usbclock.
437 CONFIG_SYS_CPC_REINIT_F
438 This CONFIG is defined when the CPC is configured as SRAM at the
439 time of U-boot entry and is required to be re-initialized.
442 Inidcates this SoC supports deep sleep feature. If deep sleep is
443 supported, core will start to execute uboot when wakes up.
445 - Generic CPU options:
446 CONFIG_SYS_GENERIC_GLOBAL_DATA
447 Defines global data is initialized in generic board board_init_f().
448 If this macro is defined, global data is created and cleared in
449 generic board board_init_f(). Without this macro, architecture/board
450 should initialize global data before calling board_init_f().
452 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
454 Defines the endianess of the CPU. Implementation of those
455 values is arch specific.
458 Freescale DDR driver in use. This type of DDR controller is
459 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
462 CONFIG_SYS_FSL_DDR_ADDR
463 Freescale DDR memory-mapped register base.
465 CONFIG_SYS_FSL_DDR_EMU
466 Specify emulator support for DDR. Some DDR features such as
467 deskew training are not available.
469 CONFIG_SYS_FSL_DDRC_GEN1
470 Freescale DDR1 controller.
472 CONFIG_SYS_FSL_DDRC_GEN2
473 Freescale DDR2 controller.
475 CONFIG_SYS_FSL_DDRC_GEN3
476 Freescale DDR3 controller.
478 CONFIG_SYS_FSL_DDRC_GEN4
479 Freescale DDR4 controller.
481 CONFIG_SYS_FSL_DDRC_ARM_GEN3
482 Freescale DDR3 controller for ARM-based SoCs.
485 Board config to use DDR1. It can be enabled for SoCs with
486 Freescale DDR1 or DDR2 controllers, depending on the board
490 Board config to use DDR2. It can be eanbeld for SoCs with
491 Freescale DDR2 or DDR3 controllers, depending on the board
495 Board config to use DDR3. It can be enabled for SoCs with
496 Freescale DDR3 or DDR3L controllers.
499 Board config to use DDR3L. It can be enabled for SoCs with
503 Board config to use DDR4. It can be enabled for SoCs with
506 CONFIG_SYS_FSL_IFC_BE
507 Defines the IFC controller register space as Big Endian
509 CONFIG_SYS_FSL_IFC_LE
510 Defines the IFC controller register space as Little Endian
512 CONFIG_SYS_FSL_PBL_PBI
513 It enables addition of RCW (Power on reset configuration) in built image.
514 Please refer doc/README.pblimage for more details
516 CONFIG_SYS_FSL_PBL_RCW
517 It adds PBI(pre-boot instructions) commands in u-boot build image.
518 PBI commands can be used to configure SoC before it starts the execution.
519 Please refer doc/README.pblimage for more details
522 It adds a target to create boot binary having SPL binary in PBI format
523 concatenated with u-boot binary.
525 CONFIG_SYS_FSL_DDR_BE
526 Defines the DDR controller register space as Big Endian
528 CONFIG_SYS_FSL_DDR_LE
529 Defines the DDR controller register space as Little Endian
531 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532 Physical address from the view of DDR controllers. It is the
533 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
534 it could be different for ARM SoCs.
536 CONFIG_SYS_FSL_DDR_INTLV_256B
537 DDR controller interleaving on 256-byte. This is a special
538 interleaving mode, handled by Dickens for Freescale layerscape
541 - Intel Monahans options:
542 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
544 Defines the Monahans run mode to oscillator
545 ratio. Valid values are 8, 16, 24, 31. The core
546 frequency is this value multiplied by 13 MHz.
548 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
550 Defines the Monahans turbo mode to oscillator
551 ratio. Valid values are 1 (default if undefined) and
552 2. The core frequency as calculated above is multiplied
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
593 CONFIG_SYS_THUMB_BUILD
595 Use this flag to build U-Boot using the Thumb instruction
596 set for ARM architectures. Thumb instruction set provides
597 better code density. For ARM architectures that support
598 Thumb2 this flag will result in Thumb2 code generated by
601 CONFIG_ARM_ERRATA_716044
602 CONFIG_ARM_ERRATA_742230
603 CONFIG_ARM_ERRATA_743622
604 CONFIG_ARM_ERRATA_751472
605 CONFIG_ARM_ERRATA_794072
606 CONFIG_ARM_ERRATA_761320
608 If set, the workarounds for these ARM errata are applied early
609 during U-Boot startup. Note that these options force the
610 workarounds to be applied; no CPU-type/version detection
611 exists, unlike the similar options in the Linux kernel. Do not
612 set these options unless they apply!
617 The frequency of the timer returned by get_timer().
618 get_timer() must operate in milliseconds and this CONFIG
619 option must be set to 1000.
621 - Linux Kernel Interface:
624 U-Boot stores all clock information in Hz
625 internally. For binary compatibility with older Linux
626 kernels (which expect the clocks passed in the
627 bd_info data to be in MHz) the environment variable
628 "clocks_in_mhz" can be defined so that U-Boot
629 converts clock data to MHZ before passing it to the
631 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
632 "clocks_in_mhz=1" is automatically included in the
635 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
637 When transferring memsize parameter to linux, some versions
638 expect it to be in bytes, others in MB.
639 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
643 New kernel versions are expecting firmware settings to be
644 passed using flattened device trees (based on open firmware
648 * New libfdt-based support
649 * Adds the "fdt" command
650 * The bootm command automatically updates the fdt
652 OF_CPU - The proper name of the cpus node (only required for
653 MPC512X and MPC5xxx based boards).
654 OF_SOC - The proper name of the soc node (only required for
655 MPC512X and MPC5xxx based boards).
656 OF_TBCLK - The timebase frequency.
657 OF_STDOUT_PATH - The path to the console device
659 boards with QUICC Engines require OF_QE to set UCC MAC
662 CONFIG_OF_BOARD_SETUP
664 Board code has addition modification that it wants to make
665 to the flat device tree before handing it off to the kernel
669 This define fills in the correct boot CPU in the boot
670 param header, the default value is zero if undefined.
674 U-Boot can detect if an IDE device is present or not.
675 If not, and this new config option is activated, U-Boot
676 removes the ATA node from the DTS before booting Linux,
677 so the Linux IDE driver does not probe the device and
678 crash. This is needed for buggy hardware (uc101) where
679 no pull down resistor is connected to the signal IDE5V_DD7.
681 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
683 This setting is mandatory for all boards that have only one
684 machine type and must be used to specify the machine type
685 number as it appears in the ARM machine registry
686 (see http://www.arm.linux.org.uk/developer/machines/).
687 Only boards that have multiple machine types supported
688 in a single configuration file and the machine type is
689 runtime discoverable, do not have to use this setting.
691 - vxWorks boot parameters:
693 bootvx constructs a valid bootline using the following
694 environments variables: bootfile, ipaddr, serverip, hostname.
695 It loads the vxWorks image pointed bootfile.
697 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
698 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
699 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
700 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
702 CONFIG_SYS_VXWORKS_ADD_PARAMS
704 Add it at the end of the bootline. E.g "u=username pw=secret"
706 Note: If a "bootargs" environment is defined, it will overwride
707 the defaults discussed just above.
709 - Cache Configuration:
710 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
711 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
712 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
714 - Cache Configuration for ARM:
715 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
717 CONFIG_SYS_PL310_BASE - Physical base address of PL310
718 controller register space
723 Define this if you want support for Amba PrimeCell PL010 UARTs.
727 Define this if you want support for Amba PrimeCell PL011 UARTs.
731 If you have Amba PrimeCell PL011 UARTs, set this variable to
732 the clock speed of the UARTs.
736 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
737 define this to a list of base addresses for each (supported)
738 port. See e.g. include/configs/versatile.h
740 CONFIG_PL011_SERIAL_RLCR
742 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
743 have separate receive and transmit line control registers. Set
744 this variable to initialize the extra register.
746 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
748 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
749 boot loader that has already initialized the UART. Define this
750 variable to flush the UART at init time.
752 CONFIG_SERIAL_HW_FLOW_CONTROL
754 Define this variable to enable hw flow control in serial driver.
755 Current user of this option is drivers/serial/nsl16550.c driver
758 Depending on board, define exactly one serial port
759 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
760 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
761 console by defining CONFIG_8xx_CONS_NONE
763 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
764 port routines must be defined elsewhere
765 (i.e. serial_init(), serial_getc(), ...)
768 Enables console device for a color framebuffer. Needs following
769 defines (cf. smiLynxEM, i8042)
770 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
772 VIDEO_HW_RECTFILL graphic chip supports
775 VIDEO_HW_BITBLT graphic chip supports
776 bit-blit (cf. smiLynxEM)
777 VIDEO_VISIBLE_COLS visible pixel columns
779 VIDEO_VISIBLE_ROWS visible pixel rows
780 VIDEO_PIXEL_SIZE bytes per pixel
781 VIDEO_DATA_FORMAT graphic data format
782 (0-5, cf. cfb_console.c)
783 VIDEO_FB_ADRS framebuffer address
784 VIDEO_KBD_INIT_FCT keyboard int fct
785 (i.e. i8042_kbd_init())
786 VIDEO_TSTC_FCT test char fct
788 VIDEO_GETC_FCT get char fct
790 CONFIG_CONSOLE_CURSOR cursor drawing on/off
791 (requires blink timer
793 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
794 CONFIG_CONSOLE_TIME display time/date info in
796 (requires CONFIG_CMD_DATE)
797 CONFIG_VIDEO_LOGO display Linux logo in
799 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
800 linux_logo.h for logo.
801 Requires CONFIG_VIDEO_LOGO
802 CONFIG_CONSOLE_EXTRA_INFO
803 additional board info beside
806 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
807 a limited number of ANSI escape sequences (cursor control,
808 erase functions and limited graphics rendition control).
810 When CONFIG_CFB_CONSOLE is defined, video console is
811 default i/o. Serial console can be forced with
812 environment 'console=serial'.
814 When CONFIG_SILENT_CONSOLE is defined, all console
815 messages (by U-Boot and Linux!) can be silenced with
816 the "silent" environment variable. See
817 doc/README.silent for more information.
819 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
821 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
825 CONFIG_BAUDRATE - in bps
826 Select one of the baudrates listed in
827 CONFIG_SYS_BAUDRATE_TABLE, see below.
828 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
830 - Console Rx buffer length
831 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
832 the maximum receive buffer length for the SMC.
833 This option is actual only for 82xx and 8xx possible.
834 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
835 must be defined, to setup the maximum idle timeout for
838 - Pre-Console Buffer:
839 Prior to the console being initialised (i.e. serial UART
840 initialised etc) all console output is silently discarded.
841 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
842 buffer any console messages prior to the console being
843 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
844 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
845 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
846 bytes are output before the console is initialised, the
847 earlier bytes are discarded.
849 'Sane' compilers will generate smaller code if
850 CONFIG_PRE_CON_BUF_SZ is a power of 2
852 - Safe printf() functions
853 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
854 the printf() functions. These are defined in
855 include/vsprintf.h and include snprintf(), vsnprintf() and
856 so on. Code size increase is approximately 300-500 bytes.
857 If this option is not given then these functions will
858 silently discard their buffer size argument - this means
859 you are not getting any overflow checking in this case.
861 - Boot Delay: CONFIG_BOOTDELAY - in seconds
862 Delay before automatically booting the default image;
863 set to -1 to disable autoboot.
864 set to -2 to autoboot with no delay and not check for abort
865 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
867 See doc/README.autoboot for these options that
868 work with CONFIG_BOOTDELAY. None are required.
869 CONFIG_BOOT_RETRY_TIME
870 CONFIG_BOOT_RETRY_MIN
871 CONFIG_AUTOBOOT_KEYED
872 CONFIG_AUTOBOOT_PROMPT
873 CONFIG_AUTOBOOT_DELAY_STR
874 CONFIG_AUTOBOOT_STOP_STR
875 CONFIG_AUTOBOOT_DELAY_STR2
876 CONFIG_AUTOBOOT_STOP_STR2
877 CONFIG_ZERO_BOOTDELAY_CHECK
878 CONFIG_RESET_TO_RETRY
882 Only needed when CONFIG_BOOTDELAY is enabled;
883 define a command string that is automatically executed
884 when no character is read on the console interface
885 within "Boot Delay" after reset.
888 This can be used to pass arguments to the bootm
889 command. The value of CONFIG_BOOTARGS goes into the
890 environment value "bootargs".
892 CONFIG_RAMBOOT and CONFIG_NFSBOOT
893 The value of these goes into the environment as
894 "ramboot" and "nfsboot" respectively, and can be used
895 as a convenience, when switching between booting from
899 CONFIG_BOOTCOUNT_LIMIT
900 Implements a mechanism for detecting a repeating reboot
902 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
905 If no softreset save registers are found on the hardware
906 "bootcount" is stored in the environment. To prevent a
907 saveenv on all reboots, the environment variable
908 "upgrade_available" is used. If "upgrade_available" is
909 0, "bootcount" is always 0, if "upgrade_available" is
910 1 "bootcount" is incremented in the environment.
911 So the Userspace Applikation must set the "upgrade_available"
912 and "bootcount" variable to 0, if a boot was successfully.
917 When this option is #defined, the existence of the
918 environment variable "preboot" will be checked
919 immediately before starting the CONFIG_BOOTDELAY
920 countdown and/or running the auto-boot command resp.
921 entering interactive mode.
923 This feature is especially useful when "preboot" is
924 automatically generated or modified. For an example
925 see the LWMON board specific code: here "preboot" is
926 modified when the user holds down a certain
927 combination of keys on the (special) keyboard when
930 - Serial Download Echo Mode:
932 If defined to 1, all characters received during a
933 serial download (using the "loads" command) are
934 echoed back. This might be needed by some terminal
935 emulations (like "cu"), but may as well just take
936 time on others. This setting #define's the initial
937 value of the "loads_echo" environment variable.
939 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
941 Select one of the baudrates listed in
942 CONFIG_SYS_BAUDRATE_TABLE, see below.
945 Monitor commands can be included or excluded
946 from the build by using the #include files
947 <config_cmd_all.h> and #undef'ing unwanted
948 commands, or using <config_cmd_default.h>
949 and augmenting with additional #define's
952 The default command configuration includes all commands
953 except those marked below with a "*".
955 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
956 CONFIG_CMD_ASKENV * ask for env variable
957 CONFIG_CMD_BDI bdinfo
958 CONFIG_CMD_BEDBUG * Include BedBug Debugger
959 CONFIG_CMD_BMP * BMP support
960 CONFIG_CMD_BSP * Board specific commands
961 CONFIG_CMD_BOOTD bootd
962 CONFIG_CMD_CACHE * icache, dcache
963 CONFIG_CMD_CLK * clock command support
964 CONFIG_CMD_CONSOLE coninfo
965 CONFIG_CMD_CRC32 * crc32
966 CONFIG_CMD_DATE * support for RTC, date/time...
967 CONFIG_CMD_DHCP * DHCP support
968 CONFIG_CMD_DIAG * Diagnostics
969 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
970 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
971 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
972 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
973 CONFIG_CMD_DTT * Digital Therm and Thermostat
974 CONFIG_CMD_ECHO echo arguments
975 CONFIG_CMD_EDITENV edit env variable
976 CONFIG_CMD_EEPROM * EEPROM read/write support
977 CONFIG_CMD_ELF * bootelf, bootvx
978 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
979 CONFIG_CMD_ENV_FLAGS * display details about env flags
980 CONFIG_CMD_ENV_EXISTS * check existence of env variable
981 CONFIG_CMD_EXPORTENV * export the environment
982 CONFIG_CMD_EXT2 * ext2 command support
983 CONFIG_CMD_EXT4 * ext4 command support
984 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
985 that work for multiple fs types
986 CONFIG_CMD_SAVEENV saveenv
987 CONFIG_CMD_FDC * Floppy Disk Support
988 CONFIG_CMD_FAT * FAT command support
989 CONFIG_CMD_FLASH flinfo, erase, protect
990 CONFIG_CMD_FPGA FPGA device initialization support
991 CONFIG_CMD_FUSE * Device fuse support
992 CONFIG_CMD_GETTIME * Get time since boot
993 CONFIG_CMD_GO * the 'go' command (exec code)
994 CONFIG_CMD_GREPENV * search environment
995 CONFIG_CMD_HASH * calculate hash / digest
996 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
997 CONFIG_CMD_I2C * I2C serial bus support
998 CONFIG_CMD_IDE * IDE harddisk support
999 CONFIG_CMD_IMI iminfo
1000 CONFIG_CMD_IMLS List all images found in NOR flash
1001 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1002 CONFIG_CMD_IMMAP * IMMR dump support
1003 CONFIG_CMD_IMPORTENV * import an environment
1004 CONFIG_CMD_INI * import data from an ini file into the env
1005 CONFIG_CMD_IRQ * irqinfo
1006 CONFIG_CMD_ITEST Integer/string test of 2 values
1007 CONFIG_CMD_JFFS2 * JFFS2 Support
1008 CONFIG_CMD_KGDB * kgdb
1009 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1010 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1012 CONFIG_CMD_LOADB loadb
1013 CONFIG_CMD_LOADS loads
1014 CONFIG_CMD_MD5SUM * print md5 message digest
1015 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1016 CONFIG_CMD_MEMINFO * Display detailed memory information
1017 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1019 CONFIG_CMD_MEMTEST * mtest
1020 CONFIG_CMD_MISC Misc functions like sleep etc
1021 CONFIG_CMD_MMC * MMC memory mapped support
1022 CONFIG_CMD_MII * MII utility commands
1023 CONFIG_CMD_MTDPARTS * MTD partition support
1024 CONFIG_CMD_NAND * NAND support
1025 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1026 CONFIG_CMD_NFS NFS support
1027 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1028 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1029 CONFIG_CMD_PCI * pciinfo
1030 CONFIG_CMD_PCMCIA * PCMCIA support
1031 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1033 CONFIG_CMD_PORTIO * Port I/O
1034 CONFIG_CMD_READ * Read raw data from partition
1035 CONFIG_CMD_REGINFO * Register dump
1036 CONFIG_CMD_RUN run command in env variable
1037 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1038 CONFIG_CMD_SAVES * save S record dump
1039 CONFIG_CMD_SCSI * SCSI Support
1040 CONFIG_CMD_SDRAM * print SDRAM configuration information
1041 (requires CONFIG_CMD_I2C)
1042 CONFIG_CMD_SETGETDCR Support for DCR Register access
1044 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1045 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1046 (requires CONFIG_CMD_MEMORY)
1047 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1048 CONFIG_CMD_SOURCE "source" command Support
1049 CONFIG_CMD_SPI * SPI serial bus support
1050 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1051 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1052 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1053 CONFIG_CMD_TIMER * access to the system tick timer
1054 CONFIG_CMD_USB * USB support
1055 CONFIG_CMD_CDP * Cisco Discover Protocol support
1056 CONFIG_CMD_MFSL * Microblaze FSL support
1057 CONFIG_CMD_XIMG Load part of Multi Image
1058 CONFIG_CMD_UUID * Generate random UUID or GUID string
1060 EXAMPLE: If you want all functions except of network
1061 support you can write:
1063 #include "config_cmd_all.h"
1064 #undef CONFIG_CMD_NET
1067 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1069 Note: Don't enable the "icache" and "dcache" commands
1070 (configuration option CONFIG_CMD_CACHE) unless you know
1071 what you (and your U-Boot users) are doing. Data
1072 cache cannot be enabled on systems like the 8xx or
1073 8260 (where accesses to the IMMR region must be
1074 uncached), and it cannot be disabled on all other
1075 systems where we (mis-) use the data cache to hold an
1076 initial stack and some data.
1079 XXX - this list needs to get updated!
1081 - Regular expression support:
1083 If this variable is defined, U-Boot is linked against
1084 the SLRE (Super Light Regular Expression) library,
1085 which adds regex support to some commands, as for
1086 example "env grep" and "setexpr".
1090 If this variable is defined, U-Boot will use a device tree
1091 to configure its devices, instead of relying on statically
1092 compiled #defines in the board file. This option is
1093 experimental and only available on a few boards. The device
1094 tree is available in the global data as gd->fdt_blob.
1096 U-Boot needs to get its device tree from somewhere. This can
1097 be done using one of the two options below:
1100 If this variable is defined, U-Boot will embed a device tree
1101 binary in its image. This device tree file should be in the
1102 board directory and called <soc>-<board>.dts. The binary file
1103 is then picked up in board_init_f() and made available through
1104 the global data structure as gd->blob.
1107 If this variable is defined, U-Boot will build a device tree
1108 binary. It will be called u-boot.dtb. Architecture-specific
1109 code will locate it at run-time. Generally this works by:
1111 cat u-boot.bin u-boot.dtb >image.bin
1113 and in fact, U-Boot does this for you, creating a file called
1114 u-boot-dtb.bin which is useful in the common case. You can
1115 still use the individual files if you need something more
1120 If this variable is defined, it enables watchdog
1121 support for the SoC. There must be support in the SoC
1122 specific code for a watchdog. For the 8xx and 8260
1123 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1124 register. When supported for a specific SoC is
1125 available, then no further board specific code should
1126 be needed to use it.
1129 When using a watchdog circuitry external to the used
1130 SoC, then define this variable and provide board
1131 specific code for the "hw_watchdog_reset" function.
1134 CONFIG_VERSION_VARIABLE
1135 If this variable is defined, an environment variable
1136 named "ver" is created by U-Boot showing the U-Boot
1137 version as printed by the "version" command.
1138 Any change to this variable will be reverted at the
1143 When CONFIG_CMD_DATE is selected, the type of the RTC
1144 has to be selected, too. Define exactly one of the
1147 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1148 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1149 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1150 CONFIG_RTC_MC146818 - use MC146818 RTC
1151 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1152 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1153 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1154 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1155 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1156 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1157 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1158 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1161 Note that if the RTC uses I2C, then the I2C interface
1162 must also be configured. See I2C Support, below.
1165 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1167 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1168 chip-ngpio pairs that tell the PCA953X driver the number of
1169 pins supported by a particular chip.
1171 Note that if the GPIO device uses I2C, then the I2C interface
1172 must also be configured. See I2C Support, below.
1174 - Timestamp Support:
1176 When CONFIG_TIMESTAMP is selected, the timestamp
1177 (date and time) of an image is printed by image
1178 commands like bootm or iminfo. This option is
1179 automatically enabled when you select CONFIG_CMD_DATE .
1181 - Partition Labels (disklabels) Supported:
1182 Zero or more of the following:
1183 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1184 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1185 Intel architecture, USB sticks, etc.
1186 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1187 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1188 bootloader. Note 2TB partition limit; see
1190 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1192 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1193 CONFIG_CMD_SCSI) you must configure support for at
1194 least one non-MTD partition type as well.
1197 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1198 board configurations files but used nowhere!
1200 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1201 be performed by calling the function
1202 ide_set_reset(int reset)
1203 which has to be defined in a board specific file
1208 Set this to enable ATAPI support.
1213 Set this to enable support for disks larger than 137GB
1214 Also look at CONFIG_SYS_64BIT_LBA.
1215 Whithout these , LBA48 support uses 32bit variables and will 'only'
1216 support disks up to 2.1TB.
1218 CONFIG_SYS_64BIT_LBA:
1219 When enabled, makes the IDE subsystem use 64bit sector addresses.
1223 At the moment only there is only support for the
1224 SYM53C8XX SCSI controller; define
1225 CONFIG_SCSI_SYM53C8XX to enable it.
1227 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1228 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1229 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1230 maximum numbers of LUNs, SCSI ID's and target
1232 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1234 The environment variable 'scsidevs' is set to the number of
1235 SCSI devices found during the last scan.
1237 - NETWORK Support (PCI):
1239 Support for Intel 8254x/8257x gigabit chips.
1242 Utility code for direct access to the SPI bus on Intel 8257x.
1243 This does not do anything useful unless you set at least one
1244 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1246 CONFIG_E1000_SPI_GENERIC
1247 Allow generic access to the SPI bus on the Intel 8257x, for
1248 example with the "sspi" command.
1251 Management command for E1000 devices. When used on devices
1252 with SPI support you can reprogram the EEPROM from U-Boot.
1254 CONFIG_E1000_FALLBACK_MAC
1255 default MAC for empty EEPROM after production.
1258 Support for Intel 82557/82559/82559ER chips.
1259 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1260 write routine for first time initialisation.
1263 Support for Digital 2114x chips.
1264 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1265 modem chip initialisation (KS8761/QS6611).
1268 Support for National dp83815 chips.
1271 Support for National dp8382[01] gigabit chips.
1273 - NETWORK Support (other):
1275 CONFIG_DRIVER_AT91EMAC
1276 Support for AT91RM9200 EMAC.
1279 Define this to use reduced MII inteface
1281 CONFIG_DRIVER_AT91EMAC_QUIET
1282 If this defined, the driver is quiet.
1283 The driver doen't show link status messages.
1285 CONFIG_CALXEDA_XGMAC
1286 Support for the Calxeda XGMAC device
1289 Support for SMSC's LAN91C96 chips.
1291 CONFIG_LAN91C96_BASE
1292 Define this to hold the physical address
1293 of the LAN91C96's I/O space
1295 CONFIG_LAN91C96_USE_32_BIT
1296 Define this to enable 32 bit addressing
1299 Support for SMSC's LAN91C111 chip
1301 CONFIG_SMC91111_BASE
1302 Define this to hold the physical address
1303 of the device (I/O space)
1305 CONFIG_SMC_USE_32_BIT
1306 Define this if data bus is 32 bits
1308 CONFIG_SMC_USE_IOFUNCS
1309 Define this to use i/o functions instead of macros
1310 (some hardware wont work with macros)
1312 CONFIG_DRIVER_TI_EMAC
1313 Support for davinci emac
1315 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1316 Define this if you have more then 3 PHYs.
1319 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1321 CONFIG_FTGMAC100_EGIGA
1322 Define this to use GE link update with gigabit PHY.
1323 Define this if FTGMAC100 is connected to gigabit PHY.
1324 If your system has 10/100 PHY only, it might not occur
1325 wrong behavior. Because PHY usually return timeout or
1326 useless data when polling gigabit status and gigabit
1327 control registers. This behavior won't affect the
1328 correctnessof 10/100 link speed update.
1331 Support for SMSC's LAN911x and LAN921x chips
1334 Define this to hold the physical address
1335 of the device (I/O space)
1337 CONFIG_SMC911X_32_BIT
1338 Define this if data bus is 32 bits
1340 CONFIG_SMC911X_16_BIT
1341 Define this if data bus is 16 bits. If your processor
1342 automatically converts one 32 bit word to two 16 bit
1343 words you may also try CONFIG_SMC911X_32_BIT.
1346 Support for Renesas on-chip Ethernet controller
1348 CONFIG_SH_ETHER_USE_PORT
1349 Define the number of ports to be used
1351 CONFIG_SH_ETHER_PHY_ADDR
1352 Define the ETH PHY's address
1354 CONFIG_SH_ETHER_CACHE_WRITEBACK
1355 If this option is set, the driver enables cache flush.
1359 Support TPM devices.
1362 Support for i2c bus TPM devices. Only one device
1363 per system is supported at this time.
1365 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1366 Define the the i2c bus number for the TPM device
1368 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1369 Define the TPM's address on the i2c bus
1371 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1372 Define the burst count bytes upper limit
1374 CONFIG_TPM_ATMEL_TWI
1375 Support for Atmel TWI TPM device. Requires I2C support.
1378 Support for generic parallel port TPM devices. Only one device
1379 per system is supported at this time.
1381 CONFIG_TPM_TIS_BASE_ADDRESS
1382 Base address where the generic TPM device is mapped
1383 to. Contemporary x86 systems usually map it at
1387 Add tpm monitor functions.
1388 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1389 provides monitor access to authorized functions.
1392 Define this to enable the TPM support library which provides
1393 functional interfaces to some TPM commands.
1394 Requires support for a TPM device.
1396 CONFIG_TPM_AUTH_SESSIONS
1397 Define this to enable authorized functions in the TPM library.
1398 Requires CONFIG_TPM and CONFIG_SHA1.
1401 At the moment only the UHCI host controller is
1402 supported (PIP405, MIP405, MPC5200); define
1403 CONFIG_USB_UHCI to enable it.
1404 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1405 and define CONFIG_USB_STORAGE to enable the USB
1408 Supported are USB Keyboards and USB Floppy drives
1410 MPC5200 USB requires additional defines:
1412 for 528 MHz Clock: 0x0001bbbb
1416 for differential drivers: 0x00001000
1417 for single ended drivers: 0x00005000
1418 for differential drivers on PSC3: 0x00000100
1419 for single ended drivers on PSC3: 0x00004100
1420 CONFIG_SYS_USB_EVENT_POLL
1421 May be defined to allow interrupt polling
1422 instead of using asynchronous interrupts
1424 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1425 txfilltuning field in the EHCI controller on reset.
1428 Define the below if you wish to use the USB console.
1429 Once firmware is rebuilt from a serial console issue the
1430 command "setenv stdin usbtty; setenv stdout usbtty" and
1431 attach your USB cable. The Unix command "dmesg" should print
1432 it has found a new device. The environment variable usbtty
1433 can be set to gserial or cdc_acm to enable your device to
1434 appear to a USB host as a Linux gserial device or a
1435 Common Device Class Abstract Control Model serial device.
1436 If you select usbtty = gserial you should be able to enumerate
1438 # modprobe usbserial vendor=0xVendorID product=0xProductID
1439 else if using cdc_acm, simply setting the environment
1440 variable usbtty to be cdc_acm should suffice. The following
1441 might be defined in YourBoardName.h
1444 Define this to build a UDC device
1447 Define this to have a tty type of device available to
1448 talk to the UDC device
1451 Define this to enable the high speed support for usb
1452 device and usbtty. If this feature is enabled, a routine
1453 int is_usbd_high_speed(void)
1454 also needs to be defined by the driver to dynamically poll
1455 whether the enumeration has succeded at high speed or full
1458 CONFIG_SYS_CONSOLE_IS_IN_ENV
1459 Define this if you want stdin, stdout &/or stderr to
1463 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1464 Derive USB clock from external clock "blah"
1465 - CONFIG_SYS_USB_EXTC_CLK 0x02
1467 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1468 Derive USB clock from brgclk
1469 - CONFIG_SYS_USB_BRG_CLK 0x04
1471 If you have a USB-IF assigned VendorID then you may wish to
1472 define your own vendor specific values either in BoardName.h
1473 or directly in usbd_vendor_info.h. If you don't define
1474 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1475 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1476 should pretend to be a Linux device to it's target host.
1478 CONFIG_USBD_MANUFACTURER
1479 Define this string as the name of your company for
1480 - CONFIG_USBD_MANUFACTURER "my company"
1482 CONFIG_USBD_PRODUCT_NAME
1483 Define this string as the name of your product
1484 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1486 CONFIG_USBD_VENDORID
1487 Define this as your assigned Vendor ID from the USB
1488 Implementors Forum. This *must* be a genuine Vendor ID
1489 to avoid polluting the USB namespace.
1490 - CONFIG_USBD_VENDORID 0xFFFF
1492 CONFIG_USBD_PRODUCTID
1493 Define this as the unique Product ID
1495 - CONFIG_USBD_PRODUCTID 0xFFFF
1497 - ULPI Layer Support:
1498 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1499 the generic ULPI layer. The generic layer accesses the ULPI PHY
1500 via the platform viewport, so you need both the genric layer and
1501 the viewport enabled. Currently only Chipidea/ARC based
1502 viewport is supported.
1503 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1504 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1505 If your ULPI phy needs a different reference clock than the
1506 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1507 the appropriate value in Hz.
1510 The MMC controller on the Intel PXA is supported. To
1511 enable this define CONFIG_MMC. The MMC can be
1512 accessed from the boot prompt by mapping the device
1513 to physical memory similar to flash. Command line is
1514 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1515 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1518 Support for Renesas on-chip MMCIF controller
1520 CONFIG_SH_MMCIF_ADDR
1521 Define the base address of MMCIF registers
1524 Define the clock frequency for MMCIF
1527 Enable the generic MMC driver
1529 CONFIG_SUPPORT_EMMC_BOOT
1530 Enable some additional features of the eMMC boot partitions.
1532 CONFIG_SUPPORT_EMMC_RPMB
1533 Enable the commands for reading, writing and programming the
1534 key for the Replay Protection Memory Block partition in eMMC.
1536 - USB Device Firmware Update (DFU) class support:
1538 This enables the USB portion of the DFU USB class
1541 This enables the command "dfu" which is used to have
1542 U-Boot create a DFU class device via USB. This command
1543 requires that the "dfu_alt_info" environment variable be
1544 set and define the alt settings to expose to the host.
1547 This enables support for exposing (e)MMC devices via DFU.
1550 This enables support for exposing NAND devices via DFU.
1553 This enables support for exposing RAM via DFU.
1554 Note: DFU spec refer to non-volatile memory usage, but
1555 allow usages beyond the scope of spec - here RAM usage,
1556 one that would help mostly the developer.
1558 CONFIG_SYS_DFU_DATA_BUF_SIZE
1559 Dfu transfer uses a buffer before writing data to the
1560 raw storage device. Make the size (in bytes) of this buffer
1561 configurable. The size of this buffer is also configurable
1562 through the "dfu_bufsiz" environment variable.
1564 CONFIG_SYS_DFU_MAX_FILE_SIZE
1565 When updating files rather than the raw storage device,
1566 we use a static buffer to copy the file into and then write
1567 the buffer once we've been given the whole file. Define
1568 this to the maximum filesize (in bytes) for the buffer.
1569 Default is 4 MiB if undefined.
1571 DFU_DEFAULT_POLL_TIMEOUT
1572 Poll timeout [ms], is the timeout a device can send to the
1573 host. The host must wait for this timeout before sending
1574 a subsequent DFU_GET_STATUS request to the device.
1576 DFU_MANIFEST_POLL_TIMEOUT
1577 Poll timeout [ms], which the device sends to the host when
1578 entering dfuMANIFEST state. Host waits this timeout, before
1579 sending again an USB request to the device.
1581 - USB Device Android Fastboot support:
1583 This enables the command "fastboot" which enables the Android
1584 fastboot mode for the platform's USB device. Fastboot is a USB
1585 protocol for downloading images, flashing and device control
1586 used on Android devices.
1587 See doc/README.android-fastboot for more information.
1589 CONFIG_ANDROID_BOOT_IMAGE
1590 This enables support for booting images which use the Android
1591 image format header.
1593 CONFIG_USB_FASTBOOT_BUF_ADDR
1594 The fastboot protocol requires a large memory buffer for
1595 downloads. Define this to the starting RAM address to use for
1598 CONFIG_USB_FASTBOOT_BUF_SIZE
1599 The fastboot protocol requires a large memory buffer for
1600 downloads. This buffer should be as large as possible for a
1601 platform. Define this to the size available RAM for fastboot.
1603 - Journaling Flash filesystem support:
1604 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1605 CONFIG_JFFS2_NAND_DEV
1606 Define these for a default partition on a NAND device
1608 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1609 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1610 Define these for a default partition on a NOR device
1612 CONFIG_SYS_JFFS_CUSTOM_PART
1613 Define this to create an own partition. You have to provide a
1614 function struct part_info* jffs2_part_info(int part_num)
1616 If you define only one JFFS2 partition you may also want to
1617 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1618 to disable the command chpart. This is the default when you
1619 have not defined a custom partition
1621 - FAT(File Allocation Table) filesystem write function support:
1624 Define this to enable support for saving memory data as a
1625 file in FAT formatted partition.
1627 This will also enable the command "fatwrite" enabling the
1628 user to write files to FAT.
1630 CBFS (Coreboot Filesystem) support
1633 Define this to enable support for reading from a Coreboot
1634 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1637 - FAT(File Allocation Table) filesystem cluster size:
1638 CONFIG_FS_FAT_MAX_CLUSTSIZE
1640 Define the max cluster size for fat operations else
1641 a default value of 65536 will be defined.
1646 Define this to enable standard (PC-Style) keyboard
1650 Standard PC keyboard driver with US (is default) and
1651 GERMAN key layout (switch via environment 'keymap=de') support.
1652 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1653 for cfb_console. Supports cursor blinking.
1656 Enables a Chrome OS keyboard using the CROS_EC interface.
1657 This uses CROS_EC to communicate with a second microcontroller
1658 which provides key scans on request.
1663 Define this to enable video support (for output to
1666 CONFIG_VIDEO_CT69000
1668 Enable Chips & Technologies 69000 Video chip
1670 CONFIG_VIDEO_SMI_LYNXEM
1671 Enable Silicon Motion SMI 712/710/810 Video chip. The
1672 video output is selected via environment 'videoout'
1673 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1676 For the CT69000 and SMI_LYNXEM drivers, videomode is
1677 selected via environment 'videomode'. Two different ways
1679 - "videomode=num" 'num' is a standard LiLo mode numbers.
1680 Following standard modes are supported (* is default):
1682 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1683 -------------+---------------------------------------------
1684 8 bits | 0x301* 0x303 0x305 0x161 0x307
1685 15 bits | 0x310 0x313 0x316 0x162 0x319
1686 16 bits | 0x311 0x314 0x317 0x163 0x31A
1687 24 bits | 0x312 0x315 0x318 ? 0x31B
1688 -------------+---------------------------------------------
1689 (i.e. setenv videomode 317; saveenv; reset;)
1691 - "videomode=bootargs" all the video parameters are parsed
1692 from the bootargs. (See drivers/video/videomodes.c)
1695 CONFIG_VIDEO_SED13806
1696 Enable Epson SED13806 driver. This driver supports 8bpp
1697 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1698 or CONFIG_VIDEO_SED13806_16BPP
1701 Enable the Freescale DIU video driver. Reference boards for
1702 SOCs that have a DIU should define this macro to enable DIU
1703 support, and should also define these other macros:
1709 CONFIG_VIDEO_SW_CURSOR
1710 CONFIG_VGA_AS_SINGLE_DEVICE
1712 CONFIG_VIDEO_BMP_LOGO
1714 The DIU driver will look for the 'video-mode' environment
1715 variable, and if defined, enable the DIU as a console during
1716 boot. See the documentation file README.video for a
1717 description of this variable.
1721 Enable the VGA video / BIOS for x86. The alternative if you
1722 are using coreboot is to use the coreboot frame buffer
1729 Define this to enable a custom keyboard support.
1730 This simply calls drv_keyboard_init() which must be
1731 defined in your board-specific files.
1732 The only board using this so far is RBC823.
1734 - LCD Support: CONFIG_LCD
1736 Define this to enable LCD support (for output to LCD
1737 display); also select one of the supported displays
1738 by defining one of these:
1742 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1744 CONFIG_NEC_NL6448AC33:
1746 NEC NL6448AC33-18. Active, color, single scan.
1748 CONFIG_NEC_NL6448BC20
1750 NEC NL6448BC20-08. 6.5", 640x480.
1751 Active, color, single scan.
1753 CONFIG_NEC_NL6448BC33_54
1755 NEC NL6448BC33-54. 10.4", 640x480.
1756 Active, color, single scan.
1760 Sharp 320x240. Active, color, single scan.
1761 It isn't 16x9, and I am not sure what it is.
1763 CONFIG_SHARP_LQ64D341
1765 Sharp LQ64D341 display, 640x480.
1766 Active, color, single scan.
1770 HLD1045 display, 640x480.
1771 Active, color, single scan.
1775 Optrex CBL50840-2 NF-FW 99 22 M5
1777 Hitachi LMG6912RPFC-00T
1781 320x240. Black & white.
1783 Normally display is black on white background; define
1784 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1786 CONFIG_LCD_ALIGNMENT
1788 Normally the LCD is page-aligned (tyically 4KB). If this is
1789 defined then the LCD will be aligned to this value instead.
1790 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1791 here, since it is cheaper to change data cache settings on
1792 a per-section basis.
1794 CONFIG_CONSOLE_SCROLL_LINES
1796 When the console need to be scrolled, this is the number of
1797 lines to scroll by. It defaults to 1. Increasing this makes
1798 the console jump but can help speed up operation when scrolling
1803 Support drawing of RLE8-compressed bitmaps on the LCD.
1807 Enables an 'i2c edid' command which can read EDID
1808 information over I2C from an attached LCD display.
1810 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1812 If this option is set, the environment is checked for
1813 a variable "splashimage". If found, the usual display
1814 of logo, copyright and system information on the LCD
1815 is suppressed and the BMP image at the address
1816 specified in "splashimage" is loaded instead. The
1817 console is redirected to the "nulldev", too. This
1818 allows for a "silent" boot where a splash screen is
1819 loaded very quickly after power-on.
1821 CONFIG_SPLASHIMAGE_GUARD
1823 If this option is set, then U-Boot will prevent the environment
1824 variable "splashimage" from being set to a problematic address
1825 (see README.displaying-bmps).
1826 This option is useful for targets where, due to alignment
1827 restrictions, an improperly aligned BMP image will cause a data
1828 abort. If you think you will not have problems with unaligned
1829 accesses (for example because your toolchain prevents them)
1830 there is no need to set this option.
1832 CONFIG_SPLASH_SCREEN_ALIGN
1834 If this option is set the splash image can be freely positioned
1835 on the screen. Environment variable "splashpos" specifies the
1836 position as "x,y". If a positive number is given it is used as
1837 number of pixel from left/top. If a negative number is given it
1838 is used as number of pixel from right/bottom. You can also
1839 specify 'm' for centering the image.
1842 setenv splashpos m,m
1843 => image at center of screen
1845 setenv splashpos 30,20
1846 => image at x = 30 and y = 20
1848 setenv splashpos -10,m
1849 => vertically centered image
1850 at x = dspWidth - bmpWidth - 9
1852 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1854 If this option is set, additionally to standard BMP
1855 images, gzipped BMP images can be displayed via the
1856 splashscreen support or the bmp command.
1858 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1860 If this option is set, 8-bit RLE compressed BMP images
1861 can be displayed via the splashscreen support or the
1864 - Do compresssing for memory range:
1867 If this option is set, it would use zlib deflate method
1868 to compress the specified memory at its best effort.
1870 - Compression support:
1873 Enabled by default to support gzip compressed images.
1877 If this option is set, support for bzip2 compressed
1878 images is included. If not, only uncompressed and gzip
1879 compressed images are supported.
1881 NOTE: the bzip2 algorithm requires a lot of RAM, so
1882 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1887 If this option is set, support for lzma compressed
1890 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1891 requires an amount of dynamic memory that is given by the
1894 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1896 Where lc and lp stand for, respectively, Literal context bits
1897 and Literal pos bits.
1899 This value is upper-bounded by 14MB in the worst case. Anyway,
1900 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1901 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1902 a very small buffer.
1904 Use the lzmainfo tool to determinate the lc and lp values and
1905 then calculate the amount of needed dynamic memory (ensuring
1906 the appropriate CONFIG_SYS_MALLOC_LEN value).
1910 If this option is set, support for LZO compressed images
1916 The address of PHY on MII bus.
1918 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1920 The clock frequency of the MII bus
1924 If this option is set, support for speed/duplex
1925 detection of gigabit PHY is included.
1927 CONFIG_PHY_RESET_DELAY
1929 Some PHY like Intel LXT971A need extra delay after
1930 reset before any MII register access is possible.
1931 For such PHY, set this option to the usec delay
1932 required. (minimum 300usec for LXT971A)
1934 CONFIG_PHY_CMD_DELAY (ppc4xx)
1936 Some PHY like Intel LXT971A need extra delay after
1937 command issued before MII status register can be read
1947 Define a default value for Ethernet address to use
1948 for the respective Ethernet interface, in case this
1949 is not determined automatically.
1954 Define a default value for the IP address to use for
1955 the default Ethernet interface, in case this is not
1956 determined through e.g. bootp.
1957 (Environment variable "ipaddr")
1959 - Server IP address:
1962 Defines a default value for the IP address of a TFTP
1963 server to contact when using the "tftboot" command.
1964 (Environment variable "serverip")
1966 CONFIG_KEEP_SERVERADDR
1968 Keeps the server's MAC address, in the env 'serveraddr'
1969 for passing to bootargs (like Linux's netconsole option)
1971 - Gateway IP address:
1974 Defines a default value for the IP address of the
1975 default router where packets to other networks are
1977 (Environment variable "gatewayip")
1982 Defines a default value for the subnet mask (or
1983 routing prefix) which is used to determine if an IP
1984 address belongs to the local subnet or needs to be
1985 forwarded through a router.
1986 (Environment variable "netmask")
1988 - Multicast TFTP Mode:
1991 Defines whether you want to support multicast TFTP as per
1992 rfc-2090; for example to work with atftp. Lets lots of targets
1993 tftp down the same boot image concurrently. Note: the Ethernet
1994 driver in use must provide a function: mcast() to join/leave a
1997 - BOOTP Recovery Mode:
1998 CONFIG_BOOTP_RANDOM_DELAY
2000 If you have many targets in a network that try to
2001 boot using BOOTP, you may want to avoid that all
2002 systems send out BOOTP requests at precisely the same
2003 moment (which would happen for instance at recovery
2004 from a power failure, when all systems will try to
2005 boot, thus flooding the BOOTP server. Defining
2006 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2007 inserted before sending out BOOTP requests. The
2008 following delays are inserted then:
2010 1st BOOTP request: delay 0 ... 1 sec
2011 2nd BOOTP request: delay 0 ... 2 sec
2012 3rd BOOTP request: delay 0 ... 4 sec
2014 BOOTP requests: delay 0 ... 8 sec
2016 - DHCP Advanced Options:
2017 You can fine tune the DHCP functionality by defining
2018 CONFIG_BOOTP_* symbols:
2020 CONFIG_BOOTP_SUBNETMASK
2021 CONFIG_BOOTP_GATEWAY
2022 CONFIG_BOOTP_HOSTNAME
2023 CONFIG_BOOTP_NISDOMAIN
2024 CONFIG_BOOTP_BOOTPATH
2025 CONFIG_BOOTP_BOOTFILESIZE
2028 CONFIG_BOOTP_SEND_HOSTNAME
2029 CONFIG_BOOTP_NTPSERVER
2030 CONFIG_BOOTP_TIMEOFFSET
2031 CONFIG_BOOTP_VENDOREX
2032 CONFIG_BOOTP_MAY_FAIL
2034 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2035 environment variable, not the BOOTP server.
2037 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2038 after the configured retry count, the call will fail
2039 instead of starting over. This can be used to fail over
2040 to Link-local IP address configuration if the DHCP server
2043 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2044 serverip from a DHCP server, it is possible that more
2045 than one DNS serverip is offered to the client.
2046 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2047 serverip will be stored in the additional environment
2048 variable "dnsip2". The first DNS serverip is always
2049 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2052 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2053 to do a dynamic update of a DNS server. To do this, they
2054 need the hostname of the DHCP requester.
2055 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2056 of the "hostname" environment variable is passed as
2057 option 12 to the DHCP server.
2059 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2061 A 32bit value in microseconds for a delay between
2062 receiving a "DHCP Offer" and sending the "DHCP Request".
2063 This fixes a problem with certain DHCP servers that don't
2064 respond 100% of the time to a "DHCP request". E.g. On an
2065 AT91RM9200 processor running at 180MHz, this delay needed
2066 to be *at least* 15,000 usec before a Windows Server 2003
2067 DHCP server would reply 100% of the time. I recommend at
2068 least 50,000 usec to be safe. The alternative is to hope
2069 that one of the retries will be successful but note that
2070 the DHCP timeout and retry process takes a longer than
2073 - Link-local IP address negotiation:
2074 Negotiate with other link-local clients on the local network
2075 for an address that doesn't require explicit configuration.
2076 This is especially useful if a DHCP server cannot be guaranteed
2077 to exist in all environments that the device must operate.
2079 See doc/README.link-local for more information.
2082 CONFIG_CDP_DEVICE_ID
2084 The device id used in CDP trigger frames.
2086 CONFIG_CDP_DEVICE_ID_PREFIX
2088 A two character string which is prefixed to the MAC address
2093 A printf format string which contains the ascii name of
2094 the port. Normally is set to "eth%d" which sets
2095 eth0 for the first Ethernet, eth1 for the second etc.
2097 CONFIG_CDP_CAPABILITIES
2099 A 32bit integer which indicates the device capabilities;
2100 0x00000010 for a normal host which does not forwards.
2104 An ascii string containing the version of the software.
2108 An ascii string containing the name of the platform.
2112 A 32bit integer sent on the trigger.
2114 CONFIG_CDP_POWER_CONSUMPTION
2116 A 16bit integer containing the power consumption of the
2117 device in .1 of milliwatts.
2119 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2121 A byte containing the id of the VLAN.
2123 - Status LED: CONFIG_STATUS_LED
2125 Several configurations allow to display the current
2126 status using a LED. For instance, the LED will blink
2127 fast while running U-Boot code, stop blinking as
2128 soon as a reply to a BOOTP request was received, and
2129 start blinking slow once the Linux kernel is running
2130 (supported by a status LED driver in the Linux
2131 kernel). Defining CONFIG_STATUS_LED enables this
2137 The status LED can be connected to a GPIO pin.
2138 In such cases, the gpio_led driver can be used as a
2139 status LED backend implementation. Define CONFIG_GPIO_LED
2140 to include the gpio_led driver in the U-Boot binary.
2142 CONFIG_GPIO_LED_INVERTED_TABLE
2143 Some GPIO connected LEDs may have inverted polarity in which
2144 case the GPIO high value corresponds to LED off state and
2145 GPIO low value corresponds to LED on state.
2146 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2147 with a list of GPIO LEDs that have inverted polarity.
2149 - CAN Support: CONFIG_CAN_DRIVER
2151 Defining CONFIG_CAN_DRIVER enables CAN driver support
2152 on those systems that support this (optional)
2153 feature, like the TQM8xxL modules.
2155 - I2C Support: CONFIG_SYS_I2C
2157 This enable the NEW i2c subsystem, and will allow you to use
2158 i2c commands at the u-boot command line (as long as you set
2159 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2160 based realtime clock chips or other i2c devices. See
2161 common/cmd_i2c.c for a description of the command line
2164 ported i2c driver to the new framework:
2165 - drivers/i2c/soft_i2c.c:
2166 - activate first bus with CONFIG_SYS_I2C_SOFT define
2167 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2168 for defining speed and slave address
2169 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2170 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2171 for defining speed and slave address
2172 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2173 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2174 for defining speed and slave address
2175 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2176 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2177 for defining speed and slave address
2179 - drivers/i2c/fsl_i2c.c:
2180 - activate i2c driver with CONFIG_SYS_I2C_FSL
2181 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2182 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2183 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2185 - If your board supports a second fsl i2c bus, define
2186 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2187 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2188 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2191 - drivers/i2c/tegra_i2c.c:
2192 - activate this driver with CONFIG_SYS_I2C_TEGRA
2193 - This driver adds 4 i2c buses with a fix speed from
2194 100000 and the slave addr 0!
2196 - drivers/i2c/ppc4xx_i2c.c
2197 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2198 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2199 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2201 - drivers/i2c/i2c_mxc.c
2202 - activate this driver with CONFIG_SYS_I2C_MXC
2203 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2204 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2205 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2206 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2207 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2208 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2209 If thoses defines are not set, default value is 100000
2210 for speed, and 0 for slave.
2212 - drivers/i2c/rcar_i2c.c:
2213 - activate this driver with CONFIG_SYS_I2C_RCAR
2214 - This driver adds 4 i2c buses
2216 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2217 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2218 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2219 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2220 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2221 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2222 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2223 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2224 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2226 - drivers/i2c/sh_i2c.c:
2227 - activate this driver with CONFIG_SYS_I2C_SH
2228 - This driver adds from 2 to 5 i2c buses
2230 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2231 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2232 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2233 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2234 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2235 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2236 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2237 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2238 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2239 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2240 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2241 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2242 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2244 - drivers/i2c/omap24xx_i2c.c
2245 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2246 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2247 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2248 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2249 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2250 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2251 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2252 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2253 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2254 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2255 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2257 - drivers/i2c/zynq_i2c.c
2258 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2259 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2260 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2262 - drivers/i2c/s3c24x0_i2c.c:
2263 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2264 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2265 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2266 with a fix speed from 100000 and the slave addr 0!
2270 CONFIG_SYS_NUM_I2C_BUSES
2271 Hold the number of i2c busses you want to use. If you
2272 don't use/have i2c muxes on your i2c bus, this
2273 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2276 CONFIG_SYS_I2C_DIRECT_BUS
2277 define this, if you don't use i2c muxes on your hardware.
2278 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2281 CONFIG_SYS_I2C_MAX_HOPS
2282 define how many muxes are maximal consecutively connected
2283 on one i2c bus. If you not use i2c muxes, omit this
2286 CONFIG_SYS_I2C_BUSES
2287 hold a list of busses you want to use, only used if
2288 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2289 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2290 CONFIG_SYS_NUM_I2C_BUSES = 9:
2292 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2293 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2294 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2295 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2296 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2297 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2298 {1, {I2C_NULL_HOP}}, \
2299 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2300 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2304 bus 0 on adapter 0 without a mux
2305 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2306 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2307 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2308 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2309 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2310 bus 6 on adapter 1 without a mux
2311 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2312 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2314 If you do not have i2c muxes on your board, omit this define.
2316 - Legacy I2C Support: CONFIG_HARD_I2C
2318 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2319 provides the following compelling advantages:
2321 - more than one i2c adapter is usable
2322 - approved multibus support
2323 - better i2c mux support
2325 ** Please consider updating your I2C driver now. **
2327 These enable legacy I2C serial bus commands. Defining
2328 CONFIG_HARD_I2C will include the appropriate I2C driver
2329 for the selected CPU.
2331 This will allow you to use i2c commands at the u-boot
2332 command line (as long as you set CONFIG_CMD_I2C in
2333 CONFIG_COMMANDS) and communicate with i2c based realtime
2334 clock chips. See common/cmd_i2c.c for a description of the
2335 command line interface.
2337 CONFIG_HARD_I2C selects a hardware I2C controller.
2339 There are several other quantities that must also be
2340 defined when you define CONFIG_HARD_I2C.
2342 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2343 to be the frequency (in Hz) at which you wish your i2c bus
2344 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2345 the CPU's i2c node address).
2347 Now, the u-boot i2c code for the mpc8xx
2348 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2349 and so its address should therefore be cleared to 0 (See,
2350 eg, MPC823e User's Manual p.16-473). So, set
2351 CONFIG_SYS_I2C_SLAVE to 0.
2353 CONFIG_SYS_I2C_INIT_MPC5XXX
2355 When a board is reset during an i2c bus transfer
2356 chips might think that the current transfer is still
2357 in progress. Reset the slave devices by sending start
2358 commands until the slave device responds.
2360 That's all that's required for CONFIG_HARD_I2C.
2362 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2363 then the following macros need to be defined (examples are
2364 from include/configs/lwmon.h):
2368 (Optional). Any commands necessary to enable the I2C
2369 controller or configure ports.
2371 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2375 (Only for MPC8260 CPU). The I/O port to use (the code
2376 assumes both bits are on the same port). Valid values
2377 are 0..3 for ports A..D.
2381 The code necessary to make the I2C data line active
2382 (driven). If the data line is open collector, this
2385 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2389 The code necessary to make the I2C data line tri-stated
2390 (inactive). If the data line is open collector, this
2393 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2397 Code that returns true if the I2C data line is high,
2400 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2404 If <bit> is true, sets the I2C data line high. If it
2405 is false, it clears it (low).
2407 eg: #define I2C_SDA(bit) \
2408 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2409 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2413 If <bit> is true, sets the I2C clock line high. If it
2414 is false, it clears it (low).
2416 eg: #define I2C_SCL(bit) \
2417 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2418 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2422 This delay is invoked four times per clock cycle so this
2423 controls the rate of data transfer. The data rate thus
2424 is 1 / (I2C_DELAY * 4). Often defined to be something
2427 #define I2C_DELAY udelay(2)
2429 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2431 If your arch supports the generic GPIO framework (asm/gpio.h),
2432 then you may alternatively define the two GPIOs that are to be
2433 used as SCL / SDA. Any of the previous I2C_xxx macros will
2434 have GPIO-based defaults assigned to them as appropriate.
2436 You should define these to the GPIO value as given directly to
2437 the generic GPIO functions.
2439 CONFIG_SYS_I2C_INIT_BOARD
2441 When a board is reset during an i2c bus transfer
2442 chips might think that the current transfer is still
2443 in progress. On some boards it is possible to access
2444 the i2c SCLK line directly, either by using the
2445 processor pin as a GPIO or by having a second pin
2446 connected to the bus. If this option is defined a
2447 custom i2c_init_board() routine in boards/xxx/board.c
2448 is run early in the boot sequence.
2450 CONFIG_SYS_I2C_BOARD_LATE_INIT
2452 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2453 defined a custom i2c_board_late_init() routine in
2454 boards/xxx/board.c is run AFTER the operations in i2c_init()
2455 is completed. This callpoint can be used to unreset i2c bus
2456 using CPU i2c controller register accesses for CPUs whose i2c
2457 controller provide such a method. It is called at the end of
2458 i2c_init() to allow i2c_init operations to setup the i2c bus
2459 controller on the CPU (e.g. setting bus speed & slave address).
2461 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2463 This option enables configuration of bi_iic_fast[] flags
2464 in u-boot bd_info structure based on u-boot environment
2465 variable "i2cfast". (see also i2cfast)
2467 CONFIG_I2C_MULTI_BUS
2469 This option allows the use of multiple I2C buses, each of which
2470 must have a controller. At any point in time, only one bus is
2471 active. To switch to a different bus, use the 'i2c dev' command.
2472 Note that bus numbering is zero-based.
2474 CONFIG_SYS_I2C_NOPROBES
2476 This option specifies a list of I2C devices that will be skipped
2477 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2478 is set, specify a list of bus-device pairs. Otherwise, specify
2479 a 1D array of device addresses
2482 #undef CONFIG_I2C_MULTI_BUS
2483 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2485 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2487 #define CONFIG_I2C_MULTI_BUS
2488 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2490 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2492 CONFIG_SYS_SPD_BUS_NUM
2494 If defined, then this indicates the I2C bus number for DDR SPD.
2495 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2497 CONFIG_SYS_RTC_BUS_NUM
2499 If defined, then this indicates the I2C bus number for the RTC.
2500 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2502 CONFIG_SYS_DTT_BUS_NUM
2504 If defined, then this indicates the I2C bus number for the DTT.
2505 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2507 CONFIG_SYS_I2C_DTT_ADDR:
2509 If defined, specifies the I2C address of the DTT device.
2510 If not defined, then U-Boot uses predefined value for
2511 specified DTT device.
2513 CONFIG_SOFT_I2C_READ_REPEATED_START
2515 defining this will force the i2c_read() function in
2516 the soft_i2c driver to perform an I2C repeated start
2517 between writing the address pointer and reading the
2518 data. If this define is omitted the default behaviour
2519 of doing a stop-start sequence will be used. Most I2C
2520 devices can use either method, but some require one or
2523 - SPI Support: CONFIG_SPI
2525 Enables SPI driver (so far only tested with
2526 SPI EEPROM, also an instance works with Crystal A/D and
2527 D/As on the SACSng board)
2531 Enables the driver for SPI controller on SuperH. Currently
2532 only SH7757 is supported.
2536 Enables extended (16-bit) SPI EEPROM addressing.
2537 (symmetrical to CONFIG_I2C_X)
2541 Enables a software (bit-bang) SPI driver rather than
2542 using hardware support. This is a general purpose
2543 driver that only requires three general I/O port pins
2544 (two outputs, one input) to function. If this is
2545 defined, the board configuration must define several
2546 SPI configuration items (port pins to use, etc). For
2547 an example, see include/configs/sacsng.h.
2551 Enables a hardware SPI driver for general-purpose reads
2552 and writes. As with CONFIG_SOFT_SPI, the board configuration
2553 must define a list of chip-select function pointers.
2554 Currently supported on some MPC8xxx processors. For an
2555 example, see include/configs/mpc8349emds.h.
2559 Enables the driver for the SPI controllers on i.MX and MXC
2560 SoCs. Currently i.MX31/35/51 are supported.
2562 - FPGA Support: CONFIG_FPGA
2564 Enables FPGA subsystem.
2566 CONFIG_FPGA_<vendor>
2568 Enables support for specific chip vendors.
2571 CONFIG_FPGA_<family>
2573 Enables support for FPGA family.
2574 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2578 Specify the number of FPGA devices to support.
2580 CONFIG_CMD_FPGA_LOADMK
2582 Enable support for fpga loadmk command
2584 CONFIG_CMD_FPGA_LOADP
2586 Enable support for fpga loadp command - load partial bitstream
2588 CONFIG_CMD_FPGA_LOADBP
2590 Enable support for fpga loadbp command - load partial bitstream
2593 CONFIG_SYS_FPGA_PROG_FEEDBACK
2595 Enable printing of hash marks during FPGA configuration.
2597 CONFIG_SYS_FPGA_CHECK_BUSY
2599 Enable checks on FPGA configuration interface busy
2600 status by the configuration function. This option
2601 will require a board or device specific function to
2606 If defined, a function that provides delays in the FPGA
2607 configuration driver.
2609 CONFIG_SYS_FPGA_CHECK_CTRLC
2610 Allow Control-C to interrupt FPGA configuration
2612 CONFIG_SYS_FPGA_CHECK_ERROR
2614 Check for configuration errors during FPGA bitfile
2615 loading. For example, abort during Virtex II
2616 configuration if the INIT_B line goes low (which
2617 indicated a CRC error).
2619 CONFIG_SYS_FPGA_WAIT_INIT
2621 Maximum time to wait for the INIT_B line to deassert
2622 after PROB_B has been deasserted during a Virtex II
2623 FPGA configuration sequence. The default time is 500
2626 CONFIG_SYS_FPGA_WAIT_BUSY
2628 Maximum time to wait for BUSY to deassert during
2629 Virtex II FPGA configuration. The default is 5 ms.
2631 CONFIG_SYS_FPGA_WAIT_CONFIG
2633 Time to wait after FPGA configuration. The default is
2636 - Configuration Management:
2639 If defined, this string will be added to the U-Boot
2640 version information (U_BOOT_VERSION)
2642 - Vendor Parameter Protection:
2644 U-Boot considers the values of the environment
2645 variables "serial#" (Board Serial Number) and
2646 "ethaddr" (Ethernet Address) to be parameters that
2647 are set once by the board vendor / manufacturer, and
2648 protects these variables from casual modification by
2649 the user. Once set, these variables are read-only,
2650 and write or delete attempts are rejected. You can
2651 change this behaviour:
2653 If CONFIG_ENV_OVERWRITE is #defined in your config
2654 file, the write protection for vendor parameters is
2655 completely disabled. Anybody can change or delete
2658 Alternatively, if you #define _both_ CONFIG_ETHADDR
2659 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2660 Ethernet address is installed in the environment,
2661 which can be changed exactly ONCE by the user. [The
2662 serial# is unaffected by this, i. e. it remains
2665 The same can be accomplished in a more flexible way
2666 for any variable by configuring the type of access
2667 to allow for those variables in the ".flags" variable
2668 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2673 Define this variable to enable the reservation of
2674 "protected RAM", i. e. RAM which is not overwritten
2675 by U-Boot. Define CONFIG_PRAM to hold the number of
2676 kB you want to reserve for pRAM. You can overwrite
2677 this default value by defining an environment
2678 variable "pram" to the number of kB you want to
2679 reserve. Note that the board info structure will
2680 still show the full amount of RAM. If pRAM is
2681 reserved, a new environment variable "mem" will
2682 automatically be defined to hold the amount of
2683 remaining RAM in a form that can be passed as boot
2684 argument to Linux, for instance like that:
2686 setenv bootargs ... mem=\${mem}
2689 This way you can tell Linux not to use this memory,
2690 either, which results in a memory region that will
2691 not be affected by reboots.
2693 *WARNING* If your board configuration uses automatic
2694 detection of the RAM size, you must make sure that
2695 this memory test is non-destructive. So far, the
2696 following board configurations are known to be
2699 IVMS8, IVML24, SPD8xx, TQM8xxL,
2700 HERMES, IP860, RPXlite, LWMON,
2703 - Access to physical memory region (> 4GB)
2704 Some basic support is provided for operations on memory not
2705 normally accessible to U-Boot - e.g. some architectures
2706 support access to more than 4GB of memory on 32-bit
2707 machines using physical address extension or similar.
2708 Define CONFIG_PHYSMEM to access this basic support, which
2709 currently only supports clearing the memory.
2714 Define this variable to stop the system in case of a
2715 fatal error, so that you have to reset it manually.
2716 This is probably NOT a good idea for an embedded
2717 system where you want the system to reboot
2718 automatically as fast as possible, but it may be
2719 useful during development since you can try to debug
2720 the conditions that lead to the situation.
2722 CONFIG_NET_RETRY_COUNT
2724 This variable defines the number of retries for
2725 network operations like ARP, RARP, TFTP, or BOOTP
2726 before giving up the operation. If not defined, a
2727 default value of 5 is used.
2731 Timeout waiting for an ARP reply in milliseconds.
2735 Timeout in milliseconds used in NFS protocol.
2736 If you encounter "ERROR: Cannot umount" in nfs command,
2737 try longer timeout such as
2738 #define CONFIG_NFS_TIMEOUT 10000UL
2740 - Command Interpreter:
2741 CONFIG_AUTO_COMPLETE
2743 Enable auto completion of commands using TAB.
2745 Note that this feature has NOT been implemented yet
2746 for the "hush" shell.
2749 CONFIG_SYS_HUSH_PARSER
2751 Define this variable to enable the "hush" shell (from
2752 Busybox) as command line interpreter, thus enabling
2753 powerful command line syntax like
2754 if...then...else...fi conditionals or `&&' and '||'
2755 constructs ("shell scripts").
2757 If undefined, you get the old, much simpler behaviour
2758 with a somewhat smaller memory footprint.
2761 CONFIG_SYS_PROMPT_HUSH_PS2
2763 This defines the secondary prompt string, which is
2764 printed when the command interpreter needs more input
2765 to complete a command. Usually "> ".
2769 In the current implementation, the local variables
2770 space and global environment variables space are
2771 separated. Local variables are those you define by
2772 simply typing `name=value'. To access a local
2773 variable later on, you have write `$name' or
2774 `${name}'; to execute the contents of a variable
2775 directly type `$name' at the command prompt.
2777 Global environment variables are those you use
2778 setenv/printenv to work with. To run a command stored
2779 in such a variable, you need to use the run command,
2780 and you must not use the '$' sign to access them.
2782 To store commands and special characters in a
2783 variable, please use double quotation marks
2784 surrounding the whole text of the variable, instead
2785 of the backslashes before semicolons and special
2788 - Commandline Editing and History:
2789 CONFIG_CMDLINE_EDITING
2791 Enable editing and History functions for interactive
2792 commandline input operations
2794 - Default Environment:
2795 CONFIG_EXTRA_ENV_SETTINGS
2797 Define this to contain any number of null terminated
2798 strings (variable = value pairs) that will be part of
2799 the default environment compiled into the boot image.
2801 For example, place something like this in your
2802 board's config file:
2804 #define CONFIG_EXTRA_ENV_SETTINGS \
2808 Warning: This method is based on knowledge about the
2809 internal format how the environment is stored by the
2810 U-Boot code. This is NOT an official, exported
2811 interface! Although it is unlikely that this format
2812 will change soon, there is no guarantee either.
2813 You better know what you are doing here.
2815 Note: overly (ab)use of the default environment is
2816 discouraged. Make sure to check other ways to preset
2817 the environment like the "source" command or the
2820 CONFIG_ENV_VARS_UBOOT_CONFIG
2822 Define this in order to add variables describing the
2823 U-Boot build configuration to the default environment.
2824 These will be named arch, cpu, board, vendor, and soc.
2826 Enabling this option will cause the following to be defined:
2834 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2836 Define this in order to add variables describing certain
2837 run-time determined information about the hardware to the
2838 environment. These will be named board_name, board_rev.
2840 CONFIG_DELAY_ENVIRONMENT
2842 Normally the environment is loaded when the board is
2843 intialised so that it is available to U-Boot. This inhibits
2844 that so that the environment is not available until
2845 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2846 this is instead controlled by the value of
2847 /config/load-environment.
2849 - DataFlash Support:
2850 CONFIG_HAS_DATAFLASH
2852 Defining this option enables DataFlash features and
2853 allows to read/write in Dataflash via the standard
2856 - Serial Flash support
2859 Defining this option enables SPI flash commands
2860 'sf probe/read/write/erase/update'.
2862 Usage requires an initial 'probe' to define the serial
2863 flash parameters, followed by read/write/erase/update
2866 The following defaults may be provided by the platform
2867 to handle the common case when only a single serial
2868 flash is present on the system.
2870 CONFIG_SF_DEFAULT_BUS Bus identifier
2871 CONFIG_SF_DEFAULT_CS Chip-select
2872 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2873 CONFIG_SF_DEFAULT_SPEED in Hz
2877 Define this option to include a destructive SPI flash
2880 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2882 Define this option to use the Bank addr/Extended addr
2883 support on SPI flashes which has size > 16Mbytes.
2885 CONFIG_SF_DUAL_FLASH Dual flash memories
2887 Define this option to use dual flash support where two flash
2888 memories can be connected with a given cs line.
2889 currently Xilinx Zynq qspi support these type of connections.
2891 - SystemACE Support:
2894 Adding this option adds support for Xilinx SystemACE
2895 chips attached via some sort of local bus. The address
2896 of the chip must also be defined in the
2897 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2899 #define CONFIG_SYSTEMACE
2900 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2902 When SystemACE support is added, the "ace" device type
2903 becomes available to the fat commands, i.e. fatls.
2905 - TFTP Fixed UDP Port:
2908 If this is defined, the environment variable tftpsrcp
2909 is used to supply the TFTP UDP source port value.
2910 If tftpsrcp isn't defined, the normal pseudo-random port
2911 number generator is used.
2913 Also, the environment variable tftpdstp is used to supply
2914 the TFTP UDP destination port value. If tftpdstp isn't
2915 defined, the normal port 69 is used.
2917 The purpose for tftpsrcp is to allow a TFTP server to
2918 blindly start the TFTP transfer using the pre-configured
2919 target IP address and UDP port. This has the effect of
2920 "punching through" the (Windows XP) firewall, allowing
2921 the remainder of the TFTP transfer to proceed normally.
2922 A better solution is to properly configure the firewall,
2923 but sometimes that is not allowed.
2928 This enables a generic 'hash' command which can produce
2929 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2933 Enable the hash verify command (hash -v). This adds to code
2936 CONFIG_SHA1 - support SHA1 hashing
2937 CONFIG_SHA256 - support SHA256 hashing
2939 Note: There is also a sha1sum command, which should perhaps
2940 be deprecated in favour of 'hash sha1'.
2942 - Freescale i.MX specific commands:
2943 CONFIG_CMD_HDMIDETECT
2944 This enables 'hdmidet' command which returns true if an
2945 HDMI monitor is detected. This command is i.MX 6 specific.
2948 This enables the 'bmode' (bootmode) command for forcing
2949 a boot from specific media.
2951 This is useful for forcing the ROM's usb downloader to
2952 activate upon a watchdog reset which is nice when iterating
2953 on U-Boot. Using the reset button or running bmode normal
2954 will set it back to normal. This command currently
2955 supports i.MX53 and i.MX6.
2960 This enables the RSA algorithm used for FIT image verification
2961 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2963 The signing part is build into mkimage regardless of this
2966 - bootcount support:
2967 CONFIG_BOOTCOUNT_LIMIT
2969 This enables the bootcounter support, see:
2970 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2973 enable special bootcounter support on at91sam9xe based boards.
2975 enable special bootcounter support on blackfin based boards.
2977 enable special bootcounter support on da850 based boards.
2978 CONFIG_BOOTCOUNT_RAM
2979 enable support for the bootcounter in RAM
2980 CONFIG_BOOTCOUNT_I2C
2981 enable support for the bootcounter on an i2c (like RTC) device.
2982 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2983 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2985 CONFIG_BOOTCOUNT_ALEN = address len
2987 - Show boot progress:
2988 CONFIG_SHOW_BOOT_PROGRESS
2990 Defining this option allows to add some board-
2991 specific code (calling a user-provided function
2992 "show_boot_progress(int)") that enables you to show
2993 the system's boot progress on some display (for
2994 example, some LED's) on your board. At the moment,
2995 the following checkpoints are implemented:
2997 - Detailed boot stage timing
2999 Define this option to get detailed timing of each stage
3000 of the boot process.
3002 CONFIG_BOOTSTAGE_USER_COUNT
3003 This is the number of available user bootstage records.
3004 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3005 a new ID will be allocated from this stash. If you exceed
3006 the limit, recording will stop.
3008 CONFIG_BOOTSTAGE_REPORT
3009 Define this to print a report before boot, similar to this:
3011 Timer summary in microseconds:
3014 3,575,678 3,575,678 board_init_f start
3015 3,575,695 17 arch_cpu_init A9
3016 3,575,777 82 arch_cpu_init done
3017 3,659,598 83,821 board_init_r start
3018 3,910,375 250,777 main_loop
3019 29,916,167 26,005,792 bootm_start
3020 30,361,327 445,160 start_kernel
3022 CONFIG_CMD_BOOTSTAGE
3023 Add a 'bootstage' command which supports printing a report
3024 and un/stashing of bootstage data.
3026 CONFIG_BOOTSTAGE_FDT
3027 Stash the bootstage information in the FDT. A root 'bootstage'
3028 node is created with each bootstage id as a child. Each child
3029 has a 'name' property and either 'mark' containing the
3030 mark time in microsecond, or 'accum' containing the
3031 accumulated time for that bootstage id in microseconds.
3036 name = "board_init_f";
3045 Code in the Linux kernel can find this in /proc/devicetree.
3047 Legacy uImage format:
3050 1 common/cmd_bootm.c before attempting to boot an image
3051 -1 common/cmd_bootm.c Image header has bad magic number
3052 2 common/cmd_bootm.c Image header has correct magic number
3053 -2 common/cmd_bootm.c Image header has bad checksum
3054 3 common/cmd_bootm.c Image header has correct checksum
3055 -3 common/cmd_bootm.c Image data has bad checksum
3056 4 common/cmd_bootm.c Image data has correct checksum
3057 -4 common/cmd_bootm.c Image is for unsupported architecture
3058 5 common/cmd_bootm.c Architecture check OK
3059 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3060 6 common/cmd_bootm.c Image Type check OK
3061 -6 common/cmd_bootm.c gunzip uncompression error
3062 -7 common/cmd_bootm.c Unimplemented compression type
3063 7 common/cmd_bootm.c Uncompression OK
3064 8 common/cmd_bootm.c No uncompress/copy overwrite error
3065 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3067 9 common/image.c Start initial ramdisk verification
3068 -10 common/image.c Ramdisk header has bad magic number
3069 -11 common/image.c Ramdisk header has bad checksum
3070 10 common/image.c Ramdisk header is OK
3071 -12 common/image.c Ramdisk data has bad checksum
3072 11 common/image.c Ramdisk data has correct checksum
3073 12 common/image.c Ramdisk verification complete, start loading
3074 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3075 13 common/image.c Start multifile image verification
3076 14 common/image.c No initial ramdisk, no multifile, continue.
3078 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3080 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3081 -31 post/post.c POST test failed, detected by post_output_backlog()
3082 -32 post/post.c POST test failed, detected by post_run_single()
3084 34 common/cmd_doc.c before loading a Image from a DOC device
3085 -35 common/cmd_doc.c Bad usage of "doc" command
3086 35 common/cmd_doc.c correct usage of "doc" command
3087 -36 common/cmd_doc.c No boot device
3088 36 common/cmd_doc.c correct boot device
3089 -37 common/cmd_doc.c Unknown Chip ID on boot device
3090 37 common/cmd_doc.c correct chip ID found, device available
3091 -38 common/cmd_doc.c Read Error on boot device
3092 38 common/cmd_doc.c reading Image header from DOC device OK
3093 -39 common/cmd_doc.c Image header has bad magic number
3094 39 common/cmd_doc.c Image header has correct magic number
3095 -40 common/cmd_doc.c Error reading Image from DOC device
3096 40 common/cmd_doc.c Image header has correct magic number
3097 41 common/cmd_ide.c before loading a Image from a IDE device
3098 -42 common/cmd_ide.c Bad usage of "ide" command
3099 42 common/cmd_ide.c correct usage of "ide" command
3100 -43 common/cmd_ide.c No boot device
3101 43 common/cmd_ide.c boot device found
3102 -44 common/cmd_ide.c Device not available
3103 44 common/cmd_ide.c Device available
3104 -45 common/cmd_ide.c wrong partition selected
3105 45 common/cmd_ide.c partition selected
3106 -46 common/cmd_ide.c Unknown partition table
3107 46 common/cmd_ide.c valid partition table found
3108 -47 common/cmd_ide.c Invalid partition type
3109 47 common/cmd_ide.c correct partition type
3110 -48 common/cmd_ide.c Error reading Image Header on boot device
3111 48 common/cmd_ide.c reading Image Header from IDE device OK
3112 -49 common/cmd_ide.c Image header has bad magic number
3113 49 common/cmd_ide.c Image header has correct magic number
3114 -50 common/cmd_ide.c Image header has bad checksum
3115 50 common/cmd_ide.c Image header has correct checksum
3116 -51 common/cmd_ide.c Error reading Image from IDE device
3117 51 common/cmd_ide.c reading Image from IDE device OK
3118 52 common/cmd_nand.c before loading a Image from a NAND device
3119 -53 common/cmd_nand.c Bad usage of "nand" command
3120 53 common/cmd_nand.c correct usage of "nand" command
3121 -54 common/cmd_nand.c No boot device
3122 54 common/cmd_nand.c boot device found
3123 -55 common/cmd_nand.c Unknown Chip ID on boot device
3124 55 common/cmd_nand.c correct chip ID found, device available
3125 -56 common/cmd_nand.c Error reading Image Header on boot device
3126 56 common/cmd_nand.c reading Image Header from NAND device OK
3127 -57 common/cmd_nand.c Image header has bad magic number
3128 57 common/cmd_nand.c Image header has correct magic number
3129 -58 common/cmd_nand.c Error reading Image from NAND device
3130 58 common/cmd_nand.c reading Image from NAND device OK
3132 -60 common/env_common.c Environment has a bad CRC, using default
3134 64 net/eth.c starting with Ethernet configuration.
3135 -64 net/eth.c no Ethernet found.
3136 65 net/eth.c Ethernet found.
3138 -80 common/cmd_net.c usage wrong
3139 80 common/cmd_net.c before calling NetLoop()
3140 -81 common/cmd_net.c some error in NetLoop() occurred
3141 81 common/cmd_net.c NetLoop() back without error
3142 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3143 82 common/cmd_net.c trying automatic boot
3144 83 common/cmd_net.c running "source" command
3145 -83 common/cmd_net.c some error in automatic boot or "source" command
3146 84 common/cmd_net.c end without errors
3151 100 common/cmd_bootm.c Kernel FIT Image has correct format
3152 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3153 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3154 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3155 102 common/cmd_bootm.c Kernel unit name specified
3156 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3157 103 common/cmd_bootm.c Found configuration node
3158 104 common/cmd_bootm.c Got kernel subimage node offset
3159 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3160 105 common/cmd_bootm.c Kernel subimage hash verification OK
3161 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3162 106 common/cmd_bootm.c Architecture check OK
3163 -106 common/cmd_bootm.c Kernel subimage has wrong type
3164 107 common/cmd_bootm.c Kernel subimage type OK
3165 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3166 108 common/cmd_bootm.c Got kernel subimage data/size
3167 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3168 -109 common/cmd_bootm.c Can't get kernel subimage type
3169 -110 common/cmd_bootm.c Can't get kernel subimage comp
3170 -111 common/cmd_bootm.c Can't get kernel subimage os
3171 -112 common/cmd_bootm.c Can't get kernel subimage load address
3172 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3174 120 common/image.c Start initial ramdisk verification
3175 -120 common/image.c Ramdisk FIT image has incorrect format
3176 121 common/image.c Ramdisk FIT image has correct format
3177 122 common/image.c No ramdisk subimage unit name, using configuration
3178 -122 common/image.c Can't get configuration for ramdisk subimage
3179 123 common/image.c Ramdisk unit name specified
3180 -124 common/image.c Can't get ramdisk subimage node offset
3181 125 common/image.c Got ramdisk subimage node offset
3182 -125 common/image.c Ramdisk subimage hash verification failed
3183 126 common/image.c Ramdisk subimage hash verification OK
3184 -126 common/image.c Ramdisk subimage for unsupported architecture
3185 127 common/image.c Architecture check OK
3186 -127 common/image.c Can't get ramdisk subimage data/size
3187 128 common/image.c Got ramdisk subimage data/size
3188 129 common/image.c Can't get ramdisk load address
3189 -129 common/image.c Got ramdisk load address
3191 -130 common/cmd_doc.c Incorrect FIT image format
3192 131 common/cmd_doc.c FIT image format OK
3194 -140 common/cmd_ide.c Incorrect FIT image format
3195 141 common/cmd_ide.c FIT image format OK
3197 -150 common/cmd_nand.c Incorrect FIT image format
3198 151 common/cmd_nand.c FIT image format OK
3200 - legacy image format:
3201 CONFIG_IMAGE_FORMAT_LEGACY
3202 enables the legacy image format support in U-Boot.
3205 enabled if CONFIG_FIT_SIGNATURE is not defined.
3207 CONFIG_DISABLE_IMAGE_LEGACY
3208 disable the legacy image format
3210 This define is introduced, as the legacy image format is
3211 enabled per default for backward compatibility.
3213 - FIT image support:
3215 Enable support for the FIT uImage format.
3217 CONFIG_FIT_BEST_MATCH
3218 When no configuration is explicitly selected, default to the
3219 one whose fdt's compatibility field best matches that of
3220 U-Boot itself. A match is considered "best" if it matches the
3221 most specific compatibility entry of U-Boot's fdt's root node.
3222 The order of entries in the configuration's fdt is ignored.
3224 CONFIG_FIT_SIGNATURE
3225 This option enables signature verification of FIT uImages,
3226 using a hash signed and verified using RSA. See
3227 doc/uImage.FIT/signature.txt for more details.
3229 WARNING: When relying on signed FIT images with required
3230 signature check the legacy image format is default
3231 disabled. If a board need legacy image format support
3232 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3234 - Standalone program support:
3235 CONFIG_STANDALONE_LOAD_ADDR
3237 This option defines a board specific value for the
3238 address where standalone program gets loaded, thus
3239 overwriting the architecture dependent default
3242 - Frame Buffer Address:
3245 Define CONFIG_FB_ADDR if you want to use specific
3246 address for frame buffer. This is typically the case
3247 when using a graphics controller has separate video
3248 memory. U-Boot will then place the frame buffer at
3249 the given address instead of dynamically reserving it
3250 in system RAM by calling lcd_setmem(), which grabs
3251 the memory for the frame buffer depending on the
3252 configured panel size.
3254 Please see board_init_f function.
3256 - Automatic software updates via TFTP server
3258 CONFIG_UPDATE_TFTP_CNT_MAX
3259 CONFIG_UPDATE_TFTP_MSEC_MAX
3261 These options enable and control the auto-update feature;
3262 for a more detailed description refer to doc/README.update.
3264 - MTD Support (mtdparts command, UBI support)
3267 Adds the MTD device infrastructure from the Linux kernel.
3268 Needed for mtdparts command support.
3270 CONFIG_MTD_PARTITIONS
3272 Adds the MTD partitioning infrastructure from the Linux
3273 kernel. Needed for UBI support.
3278 Adds commands for interacting with MTD partitions formatted
3279 with the UBI flash translation layer
3281 Requires also defining CONFIG_RBTREE
3283 CONFIG_UBI_SILENCE_MSG
3285 Make the verbose messages from UBI stop printing. This leaves
3286 warnings and errors enabled.
3291 Adds commands for interacting with UBI volumes formatted as
3292 UBIFS. UBIFS is read-only in u-boot.
3294 Requires UBI support as well as CONFIG_LZO
3296 CONFIG_UBIFS_SILENCE_MSG
3298 Make the verbose messages from UBIFS stop printing. This leaves
3299 warnings and errors enabled.
3303 Enable building of SPL globally.
3306 LDSCRIPT for linking the SPL binary.
3308 CONFIG_SPL_MAX_FOOTPRINT
3309 Maximum size in memory allocated to the SPL, BSS included.
3310 When defined, the linker checks that the actual memory
3311 used by SPL from _start to __bss_end does not exceed it.
3312 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3313 must not be both defined at the same time.
3316 Maximum size of the SPL image (text, data, rodata, and
3317 linker lists sections), BSS excluded.
3318 When defined, the linker checks that the actual size does
3321 CONFIG_SPL_TEXT_BASE
3322 TEXT_BASE for linking the SPL binary.
3324 CONFIG_SPL_RELOC_TEXT_BASE
3325 Address to relocate to. If unspecified, this is equal to
3326 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3328 CONFIG_SPL_BSS_START_ADDR
3329 Link address for the BSS within the SPL binary.
3331 CONFIG_SPL_BSS_MAX_SIZE
3332 Maximum size in memory allocated to the SPL BSS.
3333 When defined, the linker checks that the actual memory used
3334 by SPL from __bss_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 Adress of the start of the stack SPL will use
3341 CONFIG_SPL_RELOC_STACK
3342 Adress of the start of the stack SPL will use after
3343 relocation. If unspecified, this is equal to
3346 CONFIG_SYS_SPL_MALLOC_START
3347 Starting address of the malloc pool used in SPL.
3349 CONFIG_SYS_SPL_MALLOC_SIZE
3350 The size of the malloc pool used in SPL.
3352 CONFIG_SPL_FRAMEWORK
3353 Enable the SPL framework under common/. This framework
3354 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3355 NAND loading of the Linux Kernel.
3358 Enable booting directly to an OS from SPL.
3359 See also: doc/README.falcon
3361 CONFIG_SPL_DISPLAY_PRINT
3362 For ARM, enable an optional function to print more information
3363 about the running system.
3365 CONFIG_SPL_INIT_MINIMAL
3366 Arch init code should be built for a very small image
3368 CONFIG_SPL_LIBCOMMON_SUPPORT
3369 Support for common/libcommon.o in SPL binary
3371 CONFIG_SPL_LIBDISK_SUPPORT
3372 Support for disk/libdisk.o in SPL binary
3374 CONFIG_SPL_I2C_SUPPORT
3375 Support for drivers/i2c/libi2c.o in SPL binary
3377 CONFIG_SPL_GPIO_SUPPORT
3378 Support for drivers/gpio/libgpio.o in SPL binary
3380 CONFIG_SPL_MMC_SUPPORT
3381 Support for drivers/mmc/libmmc.o in SPL binary
3383 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3384 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3385 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3386 Address, size and partition on the MMC to load U-Boot from
3387 when the MMC is being used in raw mode.
3389 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3390 Sector to load kernel uImage from when MMC is being
3391 used in raw mode (for Falcon mode)
3393 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3394 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3395 Sector and number of sectors to load kernel argument
3396 parameters from when MMC is being used in raw mode
3399 CONFIG_SPL_FAT_SUPPORT
3400 Support for fs/fat/libfat.o in SPL binary
3402 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3403 Filename to read to load U-Boot when reading from FAT
3405 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3406 Filename to read to load kernel uImage when reading
3407 from FAT (for Falcon mode)
3409 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3410 Filename to read to load kernel argument parameters
3411 when reading from FAT (for Falcon mode)
3413 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3414 Set this for NAND SPL on PPC mpc83xx targets, so that
3415 start.S waits for the rest of the SPL to load before
3416 continuing (the hardware starts execution after just
3417 loading the first page rather than the full 4K).
3419 CONFIG_SPL_SKIP_RELOCATE
3420 Avoid SPL relocation
3422 CONFIG_SPL_NAND_BASE
3423 Include nand_base.c in the SPL. Requires
3424 CONFIG_SPL_NAND_DRIVERS.
3426 CONFIG_SPL_NAND_DRIVERS
3427 SPL uses normal NAND drivers, not minimal drivers.
3430 Include standard software ECC in the SPL
3432 CONFIG_SPL_NAND_SIMPLE
3433 Support for NAND boot using simple NAND drivers that
3434 expose the cmd_ctrl() interface.
3436 CONFIG_SPL_MTD_SUPPORT
3437 Support for the MTD subsystem within SPL. Useful for
3438 environment on NAND support within SPL.
3440 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3441 Set for the SPL on PPC mpc8xxx targets, support for
3442 drivers/ddr/fsl/libddr.o in SPL binary.
3444 CONFIG_SPL_COMMON_INIT_DDR
3445 Set for common ddr init with serial presence detect in
3448 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3449 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3450 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3451 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3452 CONFIG_SYS_NAND_ECCBYTES
3453 Defines the size and behavior of the NAND that SPL uses
3456 CONFIG_SPL_NAND_BOOT
3457 Add support NAND boot
3459 CONFIG_SYS_NAND_U_BOOT_OFFS
3460 Location in NAND to read U-Boot from
3462 CONFIG_SYS_NAND_U_BOOT_DST
3463 Location in memory to load U-Boot to
3465 CONFIG_SYS_NAND_U_BOOT_SIZE
3466 Size of image to load
3468 CONFIG_SYS_NAND_U_BOOT_START
3469 Entry point in loaded image to jump to
3471 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3472 Define this if you need to first read the OOB and then the
3473 data. This is used for example on davinci plattforms.
3475 CONFIG_SPL_OMAP3_ID_NAND
3476 Support for an OMAP3-specific set of functions to return the
3477 ID and MFR of the first attached NAND chip, if present.
3479 CONFIG_SPL_SERIAL_SUPPORT
3480 Support for drivers/serial/libserial.o in SPL binary
3482 CONFIG_SPL_SPI_FLASH_SUPPORT
3483 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3485 CONFIG_SPL_SPI_SUPPORT
3486 Support for drivers/spi/libspi.o in SPL binary
3488 CONFIG_SPL_RAM_DEVICE
3489 Support for running image already present in ram, in SPL binary
3491 CONFIG_SPL_LIBGENERIC_SUPPORT
3492 Support for lib/libgeneric.o in SPL binary
3494 CONFIG_SPL_ENV_SUPPORT
3495 Support for the environment operating in SPL binary
3497 CONFIG_SPL_NET_SUPPORT
3498 Support for the net/libnet.o in SPL binary.
3499 It conflicts with SPL env from storage medium specified by
3500 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3503 Image offset to which the SPL should be padded before appending
3504 the SPL payload. By default, this is defined as
3505 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3506 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3507 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3510 Final target image containing SPL and payload. Some SPLs
3511 use an arch-specific makefile fragment instead, for
3512 example if more than one image needs to be produced.
3514 CONFIG_FIT_SPL_PRINT
3515 Printing information about a FIT image adds quite a bit of
3516 code to SPL. So this is normally disabled in SPL. Use this
3517 option to re-enable it. This will affect the output of the
3518 bootm command when booting a FIT image.
3522 Enable building of TPL globally.
3525 Image offset to which the TPL should be padded before appending
3526 the TPL payload. By default, this is defined as
3527 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3528 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3529 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3534 [so far only for SMDK2400 boards]
3536 - Modem support enable:
3537 CONFIG_MODEM_SUPPORT
3539 - RTS/CTS Flow control enable:
3542 - Modem debug support:
3543 CONFIG_MODEM_SUPPORT_DEBUG
3545 Enables debugging stuff (char screen[1024], dbg())
3546 for modem support. Useful only with BDI2000.
3548 - Interrupt support (PPC):
3550 There are common interrupt_init() and timer_interrupt()
3551 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3552 for CPU specific initialization. interrupt_init_cpu()
3553 should set decrementer_count to appropriate value. If
3554 CPU resets decrementer automatically after interrupt
3555 (ppc4xx) it should set decrementer_count to zero.
3556 timer_interrupt() calls timer_interrupt_cpu() for CPU
3557 specific handling. If board has watchdog / status_led
3558 / other_activity_monitor it works automatically from
3559 general timer_interrupt().
3563 In the target system modem support is enabled when a
3564 specific key (key combination) is pressed during
3565 power-on. Otherwise U-Boot will boot normally
3566 (autoboot). The key_pressed() function is called from
3567 board_init(). Currently key_pressed() is a dummy
3568 function, returning 1 and thus enabling modem
3571 If there are no modem init strings in the
3572 environment, U-Boot proceed to autoboot; the
3573 previous output (banner, info printfs) will be
3576 See also: doc/README.Modem
3578 Board initialization settings:
3579 ------------------------------
3581 During Initialization u-boot calls a number of board specific functions
3582 to allow the preparation of board specific prerequisites, e.g. pin setup
3583 before drivers are initialized. To enable these callbacks the
3584 following configuration macros have to be defined. Currently this is
3585 architecture specific, so please check arch/your_architecture/lib/board.c
3586 typically in board_init_f() and board_init_r().
3588 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3589 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3590 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3591 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3593 Configuration Settings:
3594 -----------------------
3596 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3597 Optionally it can be defined to support 64-bit memory commands.
3599 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3600 undefine this when you're short of memory.
3602 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3603 width of the commands listed in the 'help' command output.
3605 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3606 prompt for user input.
3608 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3610 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3612 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3614 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3615 the application (usually a Linux kernel) when it is
3618 - CONFIG_SYS_BAUDRATE_TABLE:
3619 List of legal baudrate settings for this board.
3621 - CONFIG_SYS_CONSOLE_INFO_QUIET
3622 Suppress display of console information at boot.
3624 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3625 If the board specific function
3626 extern int overwrite_console (void);
3627 returns 1, the stdin, stderr and stdout are switched to the
3628 serial port, else the settings in the environment are used.
3630 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3631 Enable the call to overwrite_console().
3633 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3634 Enable overwrite of previous console environment settings.
3636 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3637 Begin and End addresses of the area used by the
3640 - CONFIG_SYS_ALT_MEMTEST:
3641 Enable an alternate, more extensive memory test.
3643 - CONFIG_SYS_MEMTEST_SCRATCH:
3644 Scratch address used by the alternate memory test
3645 You only need to set this if address zero isn't writeable
3647 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3648 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3649 this specified memory area will get subtracted from the top
3650 (end) of RAM and won't get "touched" at all by U-Boot. By
3651 fixing up gd->ram_size the Linux kernel should gets passed
3652 the now "corrected" memory size and won't touch it either.
3653 This should work for arch/ppc and arch/powerpc. Only Linux
3654 board ports in arch/powerpc with bootwrapper support that
3655 recalculate the memory size from the SDRAM controller setup
3656 will have to get fixed in Linux additionally.
3658 This option can be used as a workaround for the 440EPx/GRx
3659 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3662 WARNING: Please make sure that this value is a multiple of
3663 the Linux page size (normally 4k). If this is not the case,
3664 then the end address of the Linux memory will be located at a
3665 non page size aligned address and this could cause major
3668 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3669 Enable temporary baudrate change while serial download
3671 - CONFIG_SYS_SDRAM_BASE:
3672 Physical start address of SDRAM. _Must_ be 0 here.
3674 - CONFIG_SYS_MBIO_BASE:
3675 Physical start address of Motherboard I/O (if using a
3678 - CONFIG_SYS_FLASH_BASE:
3679 Physical start address of Flash memory.
3681 - CONFIG_SYS_MONITOR_BASE:
3682 Physical start address of boot monitor code (set by
3683 make config files to be same as the text base address
3684 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3685 CONFIG_SYS_FLASH_BASE when booting from flash.
3687 - CONFIG_SYS_MONITOR_LEN:
3688 Size of memory reserved for monitor code, used to
3689 determine _at_compile_time_ (!) if the environment is
3690 embedded within the U-Boot image, or in a separate
3693 - CONFIG_SYS_MALLOC_LEN:
3694 Size of DRAM reserved for malloc() use.
3696 - CONFIG_SYS_BOOTM_LEN:
3697 Normally compressed uImages are limited to an
3698 uncompressed size of 8 MBytes. If this is not enough,
3699 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3700 to adjust this setting to your needs.
3702 - CONFIG_SYS_BOOTMAPSZ:
3703 Maximum size of memory mapped by the startup code of
3704 the Linux kernel; all data that must be processed by
3705 the Linux kernel (bd_info, boot arguments, FDT blob if
3706 used) must be put below this limit, unless "bootm_low"
3707 environment variable is defined and non-zero. In such case
3708 all data for the Linux kernel must be between "bootm_low"
3709 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3710 variable "bootm_mapsize" will override the value of
3711 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3712 then the value in "bootm_size" will be used instead.
3714 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3715 Enable initrd_high functionality. If defined then the
3716 initrd_high feature is enabled and the bootm ramdisk subcommand
3719 - CONFIG_SYS_BOOT_GET_CMDLINE:
3720 Enables allocating and saving kernel cmdline in space between
3721 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3723 - CONFIG_SYS_BOOT_GET_KBD:
3724 Enables allocating and saving a kernel copy of the bd_info in
3725 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3727 - CONFIG_SYS_MAX_FLASH_BANKS:
3728 Max number of Flash memory banks
3730 - CONFIG_SYS_MAX_FLASH_SECT:
3731 Max number of sectors on a Flash chip
3733 - CONFIG_SYS_FLASH_ERASE_TOUT:
3734 Timeout for Flash erase operations (in ms)
3736 - CONFIG_SYS_FLASH_WRITE_TOUT:
3737 Timeout for Flash write operations (in ms)
3739 - CONFIG_SYS_FLASH_LOCK_TOUT
3740 Timeout for Flash set sector lock bit operation (in ms)
3742 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3743 Timeout for Flash clear lock bits operation (in ms)
3745 - CONFIG_SYS_FLASH_PROTECTION
3746 If defined, hardware flash sectors protection is used
3747 instead of U-Boot software protection.
3749 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3751 Enable TFTP transfers directly to flash memory;
3752 without this option such a download has to be
3753 performed in two steps: (1) download to RAM, and (2)
3754 copy from RAM to flash.
3756 The two-step approach is usually more reliable, since
3757 you can check if the download worked before you erase
3758 the flash, but in some situations (when system RAM is
3759 too limited to allow for a temporary copy of the
3760 downloaded image) this option may be very useful.
3762 - CONFIG_SYS_FLASH_CFI:
3763 Define if the flash driver uses extra elements in the
3764 common flash structure for storing flash geometry.
3766 - CONFIG_FLASH_CFI_DRIVER
3767 This option also enables the building of the cfi_flash driver
3768 in the drivers directory
3770 - CONFIG_FLASH_CFI_MTD
3771 This option enables the building of the cfi_mtd driver
3772 in the drivers directory. The driver exports CFI flash
3775 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3776 Use buffered writes to flash.
3778 - CONFIG_FLASH_SPANSION_S29WS_N
3779 s29ws-n MirrorBit flash has non-standard addresses for buffered
3782 - CONFIG_SYS_FLASH_QUIET_TEST
3783 If this option is defined, the common CFI flash doesn't
3784 print it's warning upon not recognized FLASH banks. This
3785 is useful, if some of the configured banks are only
3786 optionally available.
3788 - CONFIG_FLASH_SHOW_PROGRESS
3789 If defined (must be an integer), print out countdown
3790 digits and dots. Recommended value: 45 (9..1) for 80
3791 column displays, 15 (3..1) for 40 column displays.
3793 - CONFIG_FLASH_VERIFY
3794 If defined, the content of the flash (destination) is compared
3795 against the source after the write operation. An error message
3796 will be printed when the contents are not identical.
3797 Please note that this option is useless in nearly all cases,
3798 since such flash programming errors usually are detected earlier
3799 while unprotecting/erasing/programming. Please only enable
3800 this option if you really know what you are doing.
3802 - CONFIG_SYS_RX_ETH_BUFFER:
3803 Defines the number of Ethernet receive buffers. On some
3804 Ethernet controllers it is recommended to set this value
3805 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3806 buffers can be full shortly after enabling the interface
3807 on high Ethernet traffic.
3808 Defaults to 4 if not defined.
3810 - CONFIG_ENV_MAX_ENTRIES
3812 Maximum number of entries in the hash table that is used
3813 internally to store the environment settings. The default
3814 setting is supposed to be generous and should work in most
3815 cases. This setting can be used to tune behaviour; see
3816 lib/hashtable.c for details.
3818 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3819 - CONFIG_ENV_FLAGS_LIST_STATIC
3820 Enable validation of the values given to environment variables when
3821 calling env set. Variables can be restricted to only decimal,
3822 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3823 the variables can also be restricted to IP address or MAC address.
3825 The format of the list is:
3826 type_attribute = [s|d|x|b|i|m]
3827 access_atribute = [a|r|o|c]
3828 attributes = type_attribute[access_atribute]
3829 entry = variable_name[:attributes]
3832 The type attributes are:
3833 s - String (default)
3836 b - Boolean ([1yYtT|0nNfF])
3840 The access attributes are:
3846 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3847 Define this to a list (string) to define the ".flags"
3848 envirnoment variable in the default or embedded environment.
3850 - CONFIG_ENV_FLAGS_LIST_STATIC
3851 Define this to a list (string) to define validation that
3852 should be done if an entry is not found in the ".flags"
3853 environment variable. To override a setting in the static
3854 list, simply add an entry for the same variable name to the
3857 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3858 If defined, don't allow the -f switch to env set override variable
3861 - CONFIG_SYS_GENERIC_BOARD
3862 This selects the architecture-generic board system instead of the
3863 architecture-specific board files. It is intended to move boards
3864 to this new framework over time. Defining this will disable the
3865 arch/foo/lib/board.c file and use common/board_f.c and
3866 common/board_r.c instead. To use this option your architecture
3867 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3868 its config.mk file). If you find problems enabling this option on
3869 your board please report the problem and send patches!
3871 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3872 This is set by OMAP boards for the max time that reset should
3873 be asserted. See doc/README.omap-reset-time for details on how
3874 the value can be calulated on a given board.
3876 The following definitions that deal with the placement and management
3877 of environment data (variable area); in general, we support the
3878 following configurations:
3880 - CONFIG_BUILD_ENVCRC:
3882 Builds up envcrc with the target environment so that external utils
3883 may easily extract it and embed it in final U-Boot images.
3885 - CONFIG_ENV_IS_IN_FLASH:
3887 Define this if the environment is in flash memory.
3889 a) The environment occupies one whole flash sector, which is
3890 "embedded" in the text segment with the U-Boot code. This
3891 happens usually with "bottom boot sector" or "top boot
3892 sector" type flash chips, which have several smaller
3893 sectors at the start or the end. For instance, such a
3894 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3895 such a case you would place the environment in one of the
3896 4 kB sectors - with U-Boot code before and after it. With
3897 "top boot sector" type flash chips, you would put the
3898 environment in one of the last sectors, leaving a gap
3899 between U-Boot and the environment.
3901 - CONFIG_ENV_OFFSET:
3903 Offset of environment data (variable area) to the
3904 beginning of flash memory; for instance, with bottom boot
3905 type flash chips the second sector can be used: the offset
3906 for this sector is given here.
3908 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3912 This is just another way to specify the start address of
3913 the flash sector containing the environment (instead of
3916 - CONFIG_ENV_SECT_SIZE:
3918 Size of the sector containing the environment.
3921 b) Sometimes flash chips have few, equal sized, BIG sectors.
3922 In such a case you don't want to spend a whole sector for
3927 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3928 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3929 of this flash sector for the environment. This saves
3930 memory for the RAM copy of the environment.
3932 It may also save flash memory if you decide to use this
3933 when your environment is "embedded" within U-Boot code,
3934 since then the remainder of the flash sector could be used
3935 for U-Boot code. It should be pointed out that this is
3936 STRONGLY DISCOURAGED from a robustness point of view:
3937 updating the environment in flash makes it always
3938 necessary to erase the WHOLE sector. If something goes
3939 wrong before the contents has been restored from a copy in
3940 RAM, your target system will be dead.
3942 - CONFIG_ENV_ADDR_REDUND
3943 CONFIG_ENV_SIZE_REDUND
3945 These settings describe a second storage area used to hold
3946 a redundant copy of the environment data, so that there is
3947 a valid backup copy in case there is a power failure during
3948 a "saveenv" operation.
3950 BE CAREFUL! Any changes to the flash layout, and some changes to the
3951 source code will make it necessary to adapt <board>/u-boot.lds*
3955 - CONFIG_ENV_IS_IN_NVRAM:
3957 Define this if you have some non-volatile memory device
3958 (NVRAM, battery buffered SRAM) which you want to use for the
3964 These two #defines are used to determine the memory area you
3965 want to use for environment. It is assumed that this memory
3966 can just be read and written to, without any special
3969 BE CAREFUL! The first access to the environment happens quite early
3970 in U-Boot initalization (when we try to get the setting of for the
3971 console baudrate). You *MUST* have mapped your NVRAM area then, or
3974 Please note that even with NVRAM we still use a copy of the
3975 environment in RAM: we could work on NVRAM directly, but we want to
3976 keep settings there always unmodified except somebody uses "saveenv"
3977 to save the current settings.
3980 - CONFIG_ENV_IS_IN_EEPROM:
3982 Use this if you have an EEPROM or similar serial access
3983 device and a driver for it.
3985 - CONFIG_ENV_OFFSET:
3988 These two #defines specify the offset and size of the
3989 environment area within the total memory of your EEPROM.
3991 - CONFIG_SYS_I2C_EEPROM_ADDR:
3992 If defined, specified the chip address of the EEPROM device.
3993 The default address is zero.
3995 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3996 If defined, the number of bits used to address bytes in a
3997 single page in the EEPROM device. A 64 byte page, for example
3998 would require six bits.
4000 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4001 If defined, the number of milliseconds to delay between
4002 page writes. The default is zero milliseconds.
4004 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4005 The length in bytes of the EEPROM memory array address. Note
4006 that this is NOT the chip address length!
4008 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4009 EEPROM chips that implement "address overflow" are ones
4010 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4011 address and the extra bits end up in the "chip address" bit
4012 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4015 Note that we consider the length of the address field to
4016 still be one byte because the extra address bits are hidden
4017 in the chip address.
4019 - CONFIG_SYS_EEPROM_SIZE:
4020 The size in bytes of the EEPROM device.
4022 - CONFIG_ENV_EEPROM_IS_ON_I2C
4023 define this, if you have I2C and SPI activated, and your
4024 EEPROM, which holds the environment, is on the I2C bus.
4026 - CONFIG_I2C_ENV_EEPROM_BUS
4027 if you have an Environment on an EEPROM reached over
4028 I2C muxes, you can define here, how to reach this
4029 EEPROM. For example:
4031 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4033 EEPROM which holds the environment, is reached over
4034 a pca9547 i2c mux with address 0x70, channel 3.
4036 - CONFIG_ENV_IS_IN_DATAFLASH:
4038 Define this if you have a DataFlash memory device which you
4039 want to use for the environment.
4041 - CONFIG_ENV_OFFSET:
4045 These three #defines specify the offset and size of the
4046 environment area within the total memory of your DataFlash placed
4047 at the specified address.
4049 - CONFIG_ENV_IS_IN_REMOTE:
4051 Define this if you have a remote memory space which you
4052 want to use for the local device's environment.
4057 These two #defines specify the address and size of the
4058 environment area within the remote memory space. The
4059 local device can get the environment from remote memory
4060 space by SRIO or PCIE links.
4062 BE CAREFUL! For some special cases, the local device can not use
4063 "saveenv" command. For example, the local device will get the
4064 environment stored in a remote NOR flash by SRIO or PCIE link,
4065 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4067 - CONFIG_ENV_IS_IN_NAND:
4069 Define this if you have a NAND device which you want to use
4070 for the environment.
4072 - CONFIG_ENV_OFFSET:
4075 These two #defines specify the offset and size of the environment
4076 area within the first NAND device. CONFIG_ENV_OFFSET must be
4077 aligned to an erase block boundary.
4079 - CONFIG_ENV_OFFSET_REDUND (optional):
4081 This setting describes a second storage area of CONFIG_ENV_SIZE
4082 size used to hold a redundant copy of the environment data, so
4083 that there is a valid backup copy in case there is a power failure
4084 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4085 aligned to an erase block boundary.
4087 - CONFIG_ENV_RANGE (optional):
4089 Specifies the length of the region in which the environment
4090 can be written. This should be a multiple of the NAND device's
4091 block size. Specifying a range with more erase blocks than
4092 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4093 the range to be avoided.
4095 - CONFIG_ENV_OFFSET_OOB (optional):
4097 Enables support for dynamically retrieving the offset of the
4098 environment from block zero's out-of-band data. The
4099 "nand env.oob" command can be used to record this offset.
4100 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4101 using CONFIG_ENV_OFFSET_OOB.
4103 - CONFIG_NAND_ENV_DST
4105 Defines address in RAM to which the nand_spl code should copy the
4106 environment. If redundant environment is used, it will be copied to
4107 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4109 - CONFIG_ENV_IS_IN_UBI:
4111 Define this if you have an UBI volume that you want to use for the
4112 environment. This has the benefit of wear-leveling the environment
4113 accesses, which is important on NAND.
4115 - CONFIG_ENV_UBI_PART:
4117 Define this to a string that is the mtd partition containing the UBI.
4119 - CONFIG_ENV_UBI_VOLUME:
4121 Define this to the name of the volume that you want to store the
4124 - CONFIG_ENV_UBI_VOLUME_REDUND:
4126 Define this to the name of another volume to store a second copy of
4127 the environment in. This will enable redundant environments in UBI.
4128 It is assumed that both volumes are in the same MTD partition.
4130 - CONFIG_UBI_SILENCE_MSG
4131 - CONFIG_UBIFS_SILENCE_MSG
4133 You will probably want to define these to avoid a really noisy system
4134 when storing the env in UBI.
4136 - CONFIG_ENV_IS_IN_MMC:
4138 Define this if you have an MMC device which you want to use for the
4141 - CONFIG_SYS_MMC_ENV_DEV:
4143 Specifies which MMC device the environment is stored in.
4145 - CONFIG_SYS_MMC_ENV_PART (optional):
4147 Specifies which MMC partition the environment is stored in. If not
4148 set, defaults to partition 0, the user area. Common values might be
4149 1 (first MMC boot partition), 2 (second MMC boot partition).
4151 - CONFIG_ENV_OFFSET:
4154 These two #defines specify the offset and size of the environment
4155 area within the specified MMC device.
4157 If offset is positive (the usual case), it is treated as relative to
4158 the start of the MMC partition. If offset is negative, it is treated
4159 as relative to the end of the MMC partition. This can be useful if
4160 your board may be fitted with different MMC devices, which have
4161 different sizes for the MMC partitions, and you always want the
4162 environment placed at the very end of the partition, to leave the
4163 maximum possible space before it, to store other data.
4165 These two values are in units of bytes, but must be aligned to an
4166 MMC sector boundary.
4168 - CONFIG_ENV_OFFSET_REDUND (optional):
4170 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4171 hold a redundant copy of the environment data. This provides a
4172 valid backup copy in case the other copy is corrupted, e.g. due
4173 to a power failure during a "saveenv" operation.
4175 This value may also be positive or negative; this is handled in the
4176 same way as CONFIG_ENV_OFFSET.
4178 This value is also in units of bytes, but must also be aligned to
4179 an MMC sector boundary.
4181 - CONFIG_ENV_SIZE_REDUND (optional):
4183 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4184 set. If this value is set, it must be set to the same value as
4187 - CONFIG_SYS_SPI_INIT_OFFSET
4189 Defines offset to the initial SPI buffer area in DPRAM. The
4190 area is used at an early stage (ROM part) if the environment
4191 is configured to reside in the SPI EEPROM: We need a 520 byte
4192 scratch DPRAM area. It is used between the two initialization
4193 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4194 to be a good choice since it makes it far enough from the
4195 start of the data area as well as from the stack pointer.
4197 Please note that the environment is read-only until the monitor
4198 has been relocated to RAM and a RAM copy of the environment has been
4199 created; also, when using EEPROM you will have to use getenv_f()
4200 until then to read environment variables.
4202 The environment is protected by a CRC32 checksum. Before the monitor
4203 is relocated into RAM, as a result of a bad CRC you will be working
4204 with the compiled-in default environment - *silently*!!! [This is
4205 necessary, because the first environment variable we need is the
4206 "baudrate" setting for the console - if we have a bad CRC, we don't
4207 have any device yet where we could complain.]
4209 Note: once the monitor has been relocated, then it will complain if
4210 the default environment is used; a new CRC is computed as soon as you
4211 use the "saveenv" command to store a valid environment.
4213 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4214 Echo the inverted Ethernet link state to the fault LED.
4216 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4217 also needs to be defined.
4219 - CONFIG_SYS_FAULT_MII_ADDR:
4220 MII address of the PHY to check for the Ethernet link state.
4222 - CONFIG_NS16550_MIN_FUNCTIONS:
4223 Define this if you desire to only have use of the NS16550_init
4224 and NS16550_putc functions for the serial driver located at
4225 drivers/serial/ns16550.c. This option is useful for saving
4226 space for already greatly restricted images, including but not
4227 limited to NAND_SPL configurations.
4229 - CONFIG_DISPLAY_BOARDINFO
4230 Display information about the board that U-Boot is running on
4231 when U-Boot starts up. The board function checkboard() is called
4234 - CONFIG_DISPLAY_BOARDINFO_LATE
4235 Similar to the previous option, but display this information
4236 later, once stdio is running and output goes to the LCD, if
4239 Low Level (hardware related) configuration options:
4240 ---------------------------------------------------
4242 - CONFIG_SYS_CACHELINE_SIZE:
4243 Cache Line Size of the CPU.
4245 - CONFIG_SYS_DEFAULT_IMMR:
4246 Default address of the IMMR after system reset.
4248 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4249 and RPXsuper) to be able to adjust the position of
4250 the IMMR register after a reset.
4252 - CONFIG_SYS_CCSRBAR_DEFAULT:
4253 Default (power-on reset) physical address of CCSR on Freescale
4256 - CONFIG_SYS_CCSRBAR:
4257 Virtual address of CCSR. On a 32-bit build, this is typically
4258 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4260 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4261 for cross-platform code that uses that macro instead.
4263 - CONFIG_SYS_CCSRBAR_PHYS:
4264 Physical address of CCSR. CCSR can be relocated to a new
4265 physical address, if desired. In this case, this macro should
4266 be set to that address. Otherwise, it should be set to the
4267 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4268 is typically relocated on 36-bit builds. It is recommended
4269 that this macro be defined via the _HIGH and _LOW macros:
4271 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4272 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4274 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4275 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4276 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4277 used in assembly code, so it must not contain typecasts or
4278 integer size suffixes (e.g. "ULL").
4280 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4281 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4282 used in assembly code, so it must not contain typecasts or
4283 integer size suffixes (e.g. "ULL").
4285 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4286 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4287 forced to a value that ensures that CCSR is not relocated.
4289 - Floppy Disk Support:
4290 CONFIG_SYS_FDC_DRIVE_NUMBER
4292 the default drive number (default value 0)
4294 CONFIG_SYS_ISA_IO_STRIDE
4296 defines the spacing between FDC chipset registers
4299 CONFIG_SYS_ISA_IO_OFFSET
4301 defines the offset of register from address. It
4302 depends on which part of the data bus is connected to
4303 the FDC chipset. (default value 0)
4305 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4306 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4309 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4310 fdc_hw_init() is called at the beginning of the FDC
4311 setup. fdc_hw_init() must be provided by the board
4312 source code. It is used to make hardware dependant
4316 Most IDE controllers were designed to be connected with PCI
4317 interface. Only few of them were designed for AHB interface.
4318 When software is doing ATA command and data transfer to
4319 IDE devices through IDE-AHB controller, some additional
4320 registers accessing to these kind of IDE-AHB controller
4323 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4324 DO NOT CHANGE unless you know exactly what you're
4325 doing! (11-4) [MPC8xx/82xx systems only]
4327 - CONFIG_SYS_INIT_RAM_ADDR:
4329 Start address of memory area that can be used for
4330 initial data and stack; please note that this must be
4331 writable memory that is working WITHOUT special
4332 initialization, i. e. you CANNOT use normal RAM which
4333 will become available only after programming the
4334 memory controller and running certain initialization
4337 U-Boot uses the following memory types:
4338 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4339 - MPC824X: data cache
4340 - PPC4xx: data cache
4342 - CONFIG_SYS_GBL_DATA_OFFSET:
4344 Offset of the initial data structure in the memory
4345 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4346 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4347 data is located at the end of the available space
4348 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4349 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4350 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4351 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4354 On the MPC824X (or other systems that use the data
4355 cache for initial memory) the address chosen for
4356 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4357 point to an otherwise UNUSED address space between
4358 the top of RAM and the start of the PCI space.
4360 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4362 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4364 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4366 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4368 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4370 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4372 - CONFIG_SYS_OR_TIMING_SDRAM:
4375 - CONFIG_SYS_MAMR_PTA:
4376 periodic timer for refresh
4378 - CONFIG_SYS_DER: Debug Event Register (37-47)
4380 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4381 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4382 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4383 CONFIG_SYS_BR1_PRELIM:
4384 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4386 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4387 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4388 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4389 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4391 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4392 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4393 Machine Mode Register and Memory Periodic Timer
4394 Prescaler definitions (SDRAM timing)
4396 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4397 enable I2C microcode relocation patch (MPC8xx);
4398 define relocation offset in DPRAM [DSP2]
4400 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4401 enable SMC microcode relocation patch (MPC8xx);
4402 define relocation offset in DPRAM [SMC1]
4404 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4405 enable SPI microcode relocation patch (MPC8xx);
4406 define relocation offset in DPRAM [SCC4]
4408 - CONFIG_SYS_USE_OSCCLK:
4409 Use OSCM clock mode on MBX8xx board. Be careful,
4410 wrong setting might damage your board. Read
4411 doc/README.MBX before setting this variable!
4413 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4414 Offset of the bootmode word in DPRAM used by post
4415 (Power On Self Tests). This definition overrides
4416 #define'd default value in commproc.h resp.
4419 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4420 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4421 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4422 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4423 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4424 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4425 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4426 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4427 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4429 - CONFIG_PCI_DISABLE_PCIE:
4430 Disable PCI-Express on systems where it is supported but not
4433 - CONFIG_PCI_ENUM_ONLY
4434 Only scan through and get the devices on the busses.
4435 Don't do any setup work, presumably because someone or
4436 something has already done it, and we don't need to do it
4437 a second time. Useful for platforms that are pre-booted
4438 by coreboot or similar.
4440 - CONFIG_PCI_INDIRECT_BRIDGE:
4441 Enable support for indirect PCI bridges.
4444 Chip has SRIO or not
4447 Board has SRIO 1 port available
4450 Board has SRIO 2 port available
4452 - CONFIG_SRIO_PCIE_BOOT_MASTER
4453 Board can support master function for Boot from SRIO and PCIE
4455 - CONFIG_SYS_SRIOn_MEM_VIRT:
4456 Virtual Address of SRIO port 'n' memory region
4458 - CONFIG_SYS_SRIOn_MEM_PHYS:
4459 Physical Address of SRIO port 'n' memory region
4461 - CONFIG_SYS_SRIOn_MEM_SIZE:
4462 Size of SRIO port 'n' memory region
4464 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4465 Defined to tell the NAND controller that the NAND chip is using
4467 Not all NAND drivers use this symbol.
4468 Example of drivers that use it:
4469 - drivers/mtd/nand/ndfc.c
4470 - drivers/mtd/nand/mxc_nand.c
4472 - CONFIG_SYS_NDFC_EBC0_CFG
4473 Sets the EBC0_CFG register for the NDFC. If not defined
4474 a default value will be used.
4477 Get DDR timing information from an I2C EEPROM. Common
4478 with pluggable memory modules such as SODIMMs
4481 I2C address of the SPD EEPROM
4483 - CONFIG_SYS_SPD_BUS_NUM
4484 If SPD EEPROM is on an I2C bus other than the first
4485 one, specify here. Note that the value must resolve
4486 to something your driver can deal with.
4488 - CONFIG_SYS_DDR_RAW_TIMING
4489 Get DDR timing information from other than SPD. Common with
4490 soldered DDR chips onboard without SPD. DDR raw timing
4491 parameters are extracted from datasheet and hard-coded into
4492 header files or board specific files.
4494 - CONFIG_FSL_DDR_INTERACTIVE
4495 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4497 - CONFIG_SYS_83XX_DDR_USES_CS0
4498 Only for 83xx systems. If specified, then DDR should
4499 be configured using CS0 and CS1 instead of CS2 and CS3.
4501 - CONFIG_ETHER_ON_FEC[12]
4502 Define to enable FEC[12] on a 8xx series processor.
4504 - CONFIG_FEC[12]_PHY
4505 Define to the hardcoded PHY address which corresponds
4506 to the given FEC; i. e.
4507 #define CONFIG_FEC1_PHY 4
4508 means that the PHY with address 4 is connected to FEC1
4510 When set to -1, means to probe for first available.
4512 - CONFIG_FEC[12]_PHY_NORXERR
4513 The PHY does not have a RXERR line (RMII only).
4514 (so program the FEC to ignore it).
4517 Enable RMII mode for all FECs.
4518 Note that this is a global option, we can't
4519 have one FEC in standard MII mode and another in RMII mode.
4521 - CONFIG_CRC32_VERIFY
4522 Add a verify option to the crc32 command.
4525 => crc32 -v <address> <count> <crc32>
4527 Where address/count indicate a memory area
4528 and crc32 is the correct crc32 which the
4532 Add the "loopw" memory command. This only takes effect if
4533 the memory commands are activated globally (CONFIG_CMD_MEM).
4536 Add the "mdc" and "mwc" memory commands. These are cyclic
4541 This command will print 4 bytes (10,11,12,13) each 500 ms.
4543 => mwc.l 100 12345678 10
4544 This command will write 12345678 to address 100 all 10 ms.
4546 This only takes effect if the memory commands are activated
4547 globally (CONFIG_CMD_MEM).
4549 - CONFIG_SKIP_LOWLEVEL_INIT
4550 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4551 low level initializations (like setting up the memory
4552 controller) are omitted and/or U-Boot does not
4553 relocate itself into RAM.
4555 Normally this variable MUST NOT be defined. The only
4556 exception is when U-Boot is loaded (to RAM) by some
4557 other boot loader or by a debugger which performs
4558 these initializations itself.
4561 Modifies the behaviour of start.S when compiling a loader
4562 that is executed before the actual U-Boot. E.g. when
4563 compiling a NAND SPL.
4566 Modifies the behaviour of start.S when compiling a loader
4567 that is executed after the SPL and before the actual U-Boot.
4568 It is loaded by the SPL.
4570 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4571 Only for 85xx systems. If this variable is specified, the section
4572 .resetvec is not kept and the section .bootpg is placed in the
4573 previous 4k of the .text section.
4575 - CONFIG_ARCH_MAP_SYSMEM
4576 Generally U-Boot (and in particular the md command) uses
4577 effective address. It is therefore not necessary to regard
4578 U-Boot address as virtual addresses that need to be translated
4579 to physical addresses. However, sandbox requires this, since
4580 it maintains its own little RAM buffer which contains all
4581 addressable memory. This option causes some memory accesses
4582 to be mapped through map_sysmem() / unmap_sysmem().
4584 - CONFIG_USE_ARCH_MEMCPY
4585 CONFIG_USE_ARCH_MEMSET
4586 If these options are used a optimized version of memcpy/memset will
4587 be used if available. These functions may be faster under some
4588 conditions but may increase the binary size.
4590 - CONFIG_X86_RESET_VECTOR
4591 If defined, the x86 reset vector code is included. This is not
4592 needed when U-Boot is running from Coreboot.
4595 Defines the MPU clock speed (in MHz).
4597 NOTE : currently only supported on AM335x platforms.
4599 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4600 Enables the RTC32K OSC on AM33xx based plattforms
4602 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4603 Option to disable subpage write in NAND driver
4604 driver that uses this:
4605 drivers/mtd/nand/davinci_nand.c
4607 Freescale QE/FMAN Firmware Support:
4608 -----------------------------------
4610 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4611 loading of "firmware", which is encoded in the QE firmware binary format.
4612 This firmware often needs to be loaded during U-Boot booting, so macros
4613 are used to identify the storage device (NOR flash, SPI, etc) and the address
4616 - CONFIG_SYS_FMAN_FW_ADDR
4617 The address in the storage device where the FMAN microcode is located. The
4618 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4621 - CONFIG_SYS_QE_FW_ADDR
4622 The address in the storage device where the QE microcode is located. The
4623 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4626 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4627 The maximum possible size of the firmware. The firmware binary format
4628 has a field that specifies the actual size of the firmware, but it
4629 might not be possible to read any part of the firmware unless some
4630 local storage is allocated to hold the entire firmware first.
4632 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4633 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4634 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4635 virtual address in NOR flash.
4637 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4638 Specifies that QE/FMAN firmware is located in NAND flash.
4639 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4641 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4642 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4643 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4645 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4646 Specifies that QE/FMAN firmware is located on the primary SPI
4647 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4649 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4650 Specifies that QE/FMAN firmware is located in the remote (master)
4651 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4652 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4653 window->master inbound window->master LAW->the ucode address in
4654 master's memory space.
4656 Building the Software:
4657 ======================
4659 Building U-Boot has been tested in several native build environments
4660 and in many different cross environments. Of course we cannot support
4661 all possibly existing versions of cross development tools in all
4662 (potentially obsolete) versions. In case of tool chain problems we
4663 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4664 which is extensively used to build and test U-Boot.
4666 If you are not using a native environment, it is assumed that you
4667 have GNU cross compiling tools available in your path. In this case,
4668 you must set the environment variable CROSS_COMPILE in your shell.
4669 Note that no changes to the Makefile or any other source files are
4670 necessary. For example using the ELDK on a 4xx CPU, please enter:
4672 $ CROSS_COMPILE=ppc_4xx-
4673 $ export CROSS_COMPILE
4675 Note: If you wish to generate Windows versions of the utilities in
4676 the tools directory you can use the MinGW toolchain
4677 (http://www.mingw.org). Set your HOST tools to the MinGW
4678 toolchain and execute 'make tools'. For example:
4680 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4682 Binaries such as tools/mkimage.exe will be created which can
4683 be executed on computers running Windows.
4685 U-Boot is intended to be simple to build. After installing the
4686 sources you must configure U-Boot for one specific board type. This
4691 where "NAME_config" is the name of one of the existing configu-
4692 rations; see boards.cfg for supported names.
4694 Note: for some board special configuration names may exist; check if
4695 additional information is available from the board vendor; for
4696 instance, the TQM823L systems are available without (standard)
4697 or with LCD support. You can select such additional "features"
4698 when choosing the configuration, i. e.
4701 - will configure for a plain TQM823L, i. e. no LCD support
4703 make TQM823L_LCD_config
4704 - will configure for a TQM823L with U-Boot console on LCD
4709 Finally, type "make all", and you should get some working U-Boot
4710 images ready for download to / installation on your system:
4712 - "u-boot.bin" is a raw binary image
4713 - "u-boot" is an image in ELF binary format
4714 - "u-boot.srec" is in Motorola S-Record format
4716 By default the build is performed locally and the objects are saved
4717 in the source directory. One of the two methods can be used to change
4718 this behavior and build U-Boot to some external directory:
4720 1. Add O= to the make command line invocations:
4722 make O=/tmp/build distclean
4723 make O=/tmp/build NAME_config
4724 make O=/tmp/build all
4726 2. Set environment variable BUILD_DIR to point to the desired location:
4728 export BUILD_DIR=/tmp/build
4733 Note that the command line "O=" setting overrides the BUILD_DIR environment
4737 Please be aware that the Makefiles assume you are using GNU make, so
4738 for instance on NetBSD you might need to use "gmake" instead of
4742 If the system board that you have is not listed, then you will need
4743 to port U-Boot to your hardware platform. To do this, follow these
4746 1. Add a new configuration option for your board to the toplevel
4747 "boards.cfg" file, using the existing entries as examples.
4748 Follow the instructions there to keep the boards in order.
4749 2. Create a new directory to hold your board specific code. Add any
4750 files you need. In your board directory, you will need at least
4751 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4752 3. Create a new configuration file "include/configs/<board>.h" for
4754 3. If you're porting U-Boot to a new CPU, then also create a new
4755 directory to hold your CPU specific code. Add any files you need.
4756 4. Run "make <board>_config" with your new name.
4757 5. Type "make", and you should get a working "u-boot.srec" file
4758 to be installed on your target system.
4759 6. Debug and solve any problems that might arise.
4760 [Of course, this last step is much harder than it sounds.]
4763 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4764 ==============================================================
4766 If you have modified U-Boot sources (for instance added a new board
4767 or support for new devices, a new CPU, etc.) you are expected to
4768 provide feedback to the other developers. The feedback normally takes
4769 the form of a "patch", i. e. a context diff against a certain (latest
4770 official or latest in the git repository) version of U-Boot sources.
4772 But before you submit such a patch, please verify that your modifi-
4773 cation did not break existing code. At least make sure that *ALL* of
4774 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4775 just run the "MAKEALL" script, which will configure and build U-Boot
4776 for ALL supported system. Be warned, this will take a while. You can
4777 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4778 environment variable to the script, i. e. to use the ELDK cross tools
4781 CROSS_COMPILE=ppc_8xx- MAKEALL
4783 or to build on a native PowerPC system you can type
4785 CROSS_COMPILE=' ' MAKEALL
4787 When using the MAKEALL script, the default behaviour is to build
4788 U-Boot in the source directory. This location can be changed by
4789 setting the BUILD_DIR environment variable. Also, for each target
4790 built, the MAKEALL script saves two log files (<target>.ERR and
4791 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4792 location can be changed by setting the MAKEALL_LOGDIR environment
4793 variable. For example:
4795 export BUILD_DIR=/tmp/build
4796 export MAKEALL_LOGDIR=/tmp/log
4797 CROSS_COMPILE=ppc_8xx- MAKEALL
4799 With the above settings build objects are saved in the /tmp/build,
4800 log files are saved in the /tmp/log and the source tree remains clean
4801 during the whole build process.
4804 See also "U-Boot Porting Guide" below.
4807 Monitor Commands - Overview:
4808 ============================
4810 go - start application at address 'addr'
4811 run - run commands in an environment variable
4812 bootm - boot application image from memory
4813 bootp - boot image via network using BootP/TFTP protocol
4814 bootz - boot zImage from memory
4815 tftpboot- boot image via network using TFTP protocol
4816 and env variables "ipaddr" and "serverip"
4817 (and eventually "gatewayip")
4818 tftpput - upload a file via network using TFTP protocol
4819 rarpboot- boot image via network using RARP/TFTP protocol
4820 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4821 loads - load S-Record file over serial line
4822 loadb - load binary file over serial line (kermit mode)
4824 mm - memory modify (auto-incrementing)
4825 nm - memory modify (constant address)
4826 mw - memory write (fill)
4828 cmp - memory compare
4829 crc32 - checksum calculation
4830 i2c - I2C sub-system
4831 sspi - SPI utility commands
4832 base - print or set address offset
4833 printenv- print environment variables
4834 setenv - set environment variables
4835 saveenv - save environment variables to persistent storage
4836 protect - enable or disable FLASH write protection
4837 erase - erase FLASH memory
4838 flinfo - print FLASH memory information
4839 nand - NAND memory operations (see doc/README.nand)
4840 bdinfo - print Board Info structure
4841 iminfo - print header information for application image
4842 coninfo - print console devices and informations
4843 ide - IDE sub-system
4844 loop - infinite loop on address range
4845 loopw - infinite write loop on address range
4846 mtest - simple RAM test
4847 icache - enable or disable instruction cache
4848 dcache - enable or disable data cache
4849 reset - Perform RESET of the CPU
4850 echo - echo args to console
4851 version - print monitor version
4852 help - print online help
4853 ? - alias for 'help'
4856 Monitor Commands - Detailed Description:
4857 ========================================
4861 For now: just type "help <command>".
4864 Environment Variables:
4865 ======================
4867 U-Boot supports user configuration using Environment Variables which
4868 can be made persistent by saving to Flash memory.
4870 Environment Variables are set using "setenv", printed using
4871 "printenv", and saved to Flash using "saveenv". Using "setenv"
4872 without a value can be used to delete a variable from the
4873 environment. As long as you don't save the environment you are
4874 working with an in-memory copy. In case the Flash area containing the
4875 environment is erased by accident, a default environment is provided.
4877 Some configuration options can be set using Environment Variables.
4879 List of environment variables (most likely not complete):
4881 baudrate - see CONFIG_BAUDRATE
4883 bootdelay - see CONFIG_BOOTDELAY
4885 bootcmd - see CONFIG_BOOTCOMMAND
4887 bootargs - Boot arguments when booting an RTOS image
4889 bootfile - Name of the image to load with TFTP
4891 bootm_low - Memory range available for image processing in the bootm
4892 command can be restricted. This variable is given as
4893 a hexadecimal number and defines lowest address allowed
4894 for use by the bootm command. See also "bootm_size"
4895 environment variable. Address defined by "bootm_low" is
4896 also the base of the initial memory mapping for the Linux
4897 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4900 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4901 This variable is given as a hexadecimal number and it
4902 defines the size of the memory region starting at base
4903 address bootm_low that is accessible by the Linux kernel
4904 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4905 as the default value if it is defined, and bootm_size is
4908 bootm_size - Memory range available for image processing in the bootm
4909 command can be restricted. This variable is given as
4910 a hexadecimal number and defines the size of the region
4911 allowed for use by the bootm command. See also "bootm_low"
4912 environment variable.
4914 updatefile - Location of the software update file on a TFTP server, used
4915 by the automatic software update feature. Please refer to
4916 documentation in doc/README.update for more details.
4918 autoload - if set to "no" (any string beginning with 'n'),
4919 "bootp" will just load perform a lookup of the
4920 configuration from the BOOTP server, but not try to
4921 load any image using TFTP
4923 autostart - if set to "yes", an image loaded using the "bootp",
4924 "rarpboot", "tftpboot" or "diskboot" commands will
4925 be automatically started (by internally calling
4928 If set to "no", a standalone image passed to the
4929 "bootm" command will be copied to the load address
4930 (and eventually uncompressed), but NOT be started.
4931 This can be used to load and uncompress arbitrary
4934 fdt_high - if set this restricts the maximum address that the
4935 flattened device tree will be copied into upon boot.
4936 For example, if you have a system with 1 GB memory
4937 at physical address 0x10000000, while Linux kernel
4938 only recognizes the first 704 MB as low memory, you
4939 may need to set fdt_high as 0x3C000000 to have the
4940 device tree blob be copied to the maximum address
4941 of the 704 MB low memory, so that Linux kernel can
4942 access it during the boot procedure.
4944 If this is set to the special value 0xFFFFFFFF then
4945 the fdt will not be copied at all on boot. For this
4946 to work it must reside in writable memory, have
4947 sufficient padding on the end of it for u-boot to
4948 add the information it needs into it, and the memory
4949 must be accessible by the kernel.
4951 fdtcontroladdr- if set this is the address of the control flattened
4952 device tree used by U-Boot when CONFIG_OF_CONTROL is
4955 i2cfast - (PPC405GP|PPC405EP only)
4956 if set to 'y' configures Linux I2C driver for fast
4957 mode (400kHZ). This environment variable is used in
4958 initialization code. So, for changes to be effective
4959 it must be saved and board must be reset.
4961 initrd_high - restrict positioning of initrd images:
4962 If this variable is not set, initrd images will be
4963 copied to the highest possible address in RAM; this
4964 is usually what you want since it allows for
4965 maximum initrd size. If for some reason you want to
4966 make sure that the initrd image is loaded below the
4967 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4968 variable to a value of "no" or "off" or "0".
4969 Alternatively, you can set it to a maximum upper
4970 address to use (U-Boot will still check that it
4971 does not overwrite the U-Boot stack and data).
4973 For instance, when you have a system with 16 MB
4974 RAM, and want to reserve 4 MB from use by Linux,
4975 you can do this by adding "mem=12M" to the value of
4976 the "bootargs" variable. However, now you must make
4977 sure that the initrd image is placed in the first
4978 12 MB as well - this can be done with
4980 setenv initrd_high 00c00000
4982 If you set initrd_high to 0xFFFFFFFF, this is an
4983 indication to U-Boot that all addresses are legal
4984 for the Linux kernel, including addresses in flash
4985 memory. In this case U-Boot will NOT COPY the
4986 ramdisk at all. This may be useful to reduce the
4987 boot time on your system, but requires that this
4988 feature is supported by your Linux kernel.
4990 ipaddr - IP address; needed for tftpboot command
4992 loadaddr - Default load address for commands like "bootp",
4993 "rarpboot", "tftpboot", "loadb" or "diskboot"
4995 loads_echo - see CONFIG_LOADS_ECHO
4997 serverip - TFTP server IP address; needed for tftpboot command
4999 bootretry - see CONFIG_BOOT_RETRY_TIME
5001 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5003 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5005 ethprime - controls which interface is used first.
5007 ethact - controls which interface is currently active.
5008 For example you can do the following
5010 => setenv ethact FEC
5011 => ping 192.168.0.1 # traffic sent on FEC
5012 => setenv ethact SCC
5013 => ping 10.0.0.1 # traffic sent on SCC
5015 ethrotate - When set to "no" U-Boot does not go through all
5016 available network interfaces.
5017 It just stays at the currently selected interface.
5019 netretry - When set to "no" each network operation will
5020 either succeed or fail without retrying.
5021 When set to "once" the network operation will
5022 fail when all the available network interfaces
5023 are tried once without success.
5024 Useful on scripts which control the retry operation
5027 npe_ucode - set load address for the NPE microcode
5029 silent_linux - If set then linux will be told to boot silently, by
5030 changing the console to be empty. If "yes" it will be
5031 made silent. If "no" it will not be made silent. If
5032 unset, then it will be made silent if the U-Boot console
5035 tftpsrcport - If this is set, the value is used for TFTP's
5038 tftpdstport - If this is set, the value is used for TFTP's UDP
5039 destination port instead of the Well Know Port 69.
5041 tftpblocksize - Block size to use for TFTP transfers; if not set,
5042 we use the TFTP server's default block size
5044 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5045 seconds, minimum value is 1000 = 1 second). Defines
5046 when a packet is considered to be lost so it has to
5047 be retransmitted. The default is 5000 = 5 seconds.
5048 Lowering this value may make downloads succeed
5049 faster in networks with high packet loss rates or
5050 with unreliable TFTP servers.
5052 vlan - When set to a value < 4095 the traffic over
5053 Ethernet is encapsulated/received over 802.1q
5056 The following image location variables contain the location of images
5057 used in booting. The "Image" column gives the role of the image and is
5058 not an environment variable name. The other columns are environment
5059 variable names. "File Name" gives the name of the file on a TFTP
5060 server, "RAM Address" gives the location in RAM the image will be
5061 loaded to, and "Flash Location" gives the image's address in NOR
5062 flash or offset in NAND flash.
5064 *Note* - these variables don't have to be defined for all boards, some
5065 boards currenlty use other variables for these purposes, and some
5066 boards use these variables for other purposes.
5068 Image File Name RAM Address Flash Location
5069 ----- --------- ----------- --------------
5070 u-boot u-boot u-boot_addr_r u-boot_addr
5071 Linux kernel bootfile kernel_addr_r kernel_addr
5072 device tree blob fdtfile fdt_addr_r fdt_addr
5073 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5075 The following environment variables may be used and automatically
5076 updated by the network boot commands ("bootp" and "rarpboot"),
5077 depending the information provided by your boot server:
5079 bootfile - see above
5080 dnsip - IP address of your Domain Name Server
5081 dnsip2 - IP address of your secondary Domain Name Server
5082 gatewayip - IP address of the Gateway (Router) to use
5083 hostname - Target hostname
5085 netmask - Subnet Mask
5086 rootpath - Pathname of the root filesystem on the NFS server
5087 serverip - see above
5090 There are two special Environment Variables:
5092 serial# - contains hardware identification information such
5093 as type string and/or serial number
5094 ethaddr - Ethernet address
5096 These variables can be set only once (usually during manufacturing of
5097 the board). U-Boot refuses to delete or overwrite these variables
5098 once they have been set once.
5101 Further special Environment Variables:
5103 ver - Contains the U-Boot version string as printed
5104 with the "version" command. This variable is
5105 readonly (see CONFIG_VERSION_VARIABLE).
5108 Please note that changes to some configuration parameters may take
5109 only effect after the next boot (yes, that's just like Windoze :-).
5112 Callback functions for environment variables:
5113 ---------------------------------------------
5115 For some environment variables, the behavior of u-boot needs to change
5116 when their values are changed. This functionailty allows functions to
5117 be associated with arbitrary variables. On creation, overwrite, or
5118 deletion, the callback will provide the opportunity for some side
5119 effect to happen or for the change to be rejected.
5121 The callbacks are named and associated with a function using the
5122 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5124 These callbacks are associated with variables in one of two ways. The
5125 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5126 in the board configuration to a string that defines a list of
5127 associations. The list must be in the following format:
5129 entry = variable_name[:callback_name]
5132 If the callback name is not specified, then the callback is deleted.
5133 Spaces are also allowed anywhere in the list.
5135 Callbacks can also be associated by defining the ".callbacks" variable
5136 with the same list format above. Any association in ".callbacks" will
5137 override any association in the static list. You can define
5138 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5139 ".callbacks" envirnoment variable in the default or embedded environment.
5142 Command Line Parsing:
5143 =====================
5145 There are two different command line parsers available with U-Boot:
5146 the old "simple" one, and the much more powerful "hush" shell:
5148 Old, simple command line parser:
5149 --------------------------------
5151 - supports environment variables (through setenv / saveenv commands)
5152 - several commands on one line, separated by ';'
5153 - variable substitution using "... ${name} ..." syntax
5154 - special characters ('$', ';') can be escaped by prefixing with '\',
5156 setenv bootcmd bootm \${address}
5157 - You can also escape text by enclosing in single apostrophes, for example:
5158 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5163 - similar to Bourne shell, with control structures like
5164 if...then...else...fi, for...do...done; while...do...done,
5165 until...do...done, ...
5166 - supports environment ("global") variables (through setenv / saveenv
5167 commands) and local shell variables (through standard shell syntax
5168 "name=value"); only environment variables can be used with "run"
5174 (1) If a command line (or an environment variable executed by a "run"
5175 command) contains several commands separated by semicolon, and
5176 one of these commands fails, then the remaining commands will be
5179 (2) If you execute several variables with one call to run (i. e.
5180 calling run with a list of variables as arguments), any failing
5181 command will cause "run" to terminate, i. e. the remaining
5182 variables are not executed.
5184 Note for Redundant Ethernet Interfaces:
5185 =======================================
5187 Some boards come with redundant Ethernet interfaces; U-Boot supports
5188 such configurations and is capable of automatic selection of a
5189 "working" interface when needed. MAC assignment works as follows:
5191 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5192 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5193 "eth1addr" (=>eth1), "eth2addr", ...
5195 If the network interface stores some valid MAC address (for instance
5196 in SROM), this is used as default address if there is NO correspon-
5197 ding setting in the environment; if the corresponding environment
5198 variable is set, this overrides the settings in the card; that means:
5200 o If the SROM has a valid MAC address, and there is no address in the
5201 environment, the SROM's address is used.
5203 o If there is no valid address in the SROM, and a definition in the
5204 environment exists, then the value from the environment variable is
5207 o If both the SROM and the environment contain a MAC address, and
5208 both addresses are the same, this MAC address is used.
5210 o If both the SROM and the environment contain a MAC address, and the
5211 addresses differ, the value from the environment is used and a
5214 o If neither SROM nor the environment contain a MAC address, an error
5217 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5218 will be programmed into hardware as part of the initialization process. This
5219 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5220 The naming convention is as follows:
5221 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5226 U-Boot is capable of booting (and performing other auxiliary operations on)
5227 images in two formats:
5229 New uImage format (FIT)
5230 -----------------------
5232 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5233 to Flattened Device Tree). It allows the use of images with multiple
5234 components (several kernels, ramdisks, etc.), with contents protected by
5235 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5241 Old image format is based on binary files which can be basically anything,
5242 preceded by a special header; see the definitions in include/image.h for
5243 details; basically, the header defines the following image properties:
5245 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5246 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5247 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5248 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5250 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5251 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5252 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5253 * Compression Type (uncompressed, gzip, bzip2)
5259 The header is marked by a special Magic Number, and both the header
5260 and the data portions of the image are secured against corruption by
5267 Although U-Boot should support any OS or standalone application
5268 easily, the main focus has always been on Linux during the design of
5271 U-Boot includes many features that so far have been part of some
5272 special "boot loader" code within the Linux kernel. Also, any
5273 "initrd" images to be used are no longer part of one big Linux image;
5274 instead, kernel and "initrd" are separate images. This implementation
5275 serves several purposes:
5277 - the same features can be used for other OS or standalone
5278 applications (for instance: using compressed images to reduce the
5279 Flash memory footprint)
5281 - it becomes much easier to port new Linux kernel versions because
5282 lots of low-level, hardware dependent stuff are done by U-Boot
5284 - the same Linux kernel image can now be used with different "initrd"
5285 images; of course this also means that different kernel images can
5286 be run with the same "initrd". This makes testing easier (you don't
5287 have to build a new "zImage.initrd" Linux image when you just
5288 change a file in your "initrd"). Also, a field-upgrade of the
5289 software is easier now.
5295 Porting Linux to U-Boot based systems:
5296 ---------------------------------------
5298 U-Boot cannot save you from doing all the necessary modifications to
5299 configure the Linux device drivers for use with your target hardware
5300 (no, we don't intend to provide a full virtual machine interface to
5303 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5305 Just make sure your machine specific header file (for instance
5306 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5307 Information structure as we define in include/asm-<arch>/u-boot.h,
5308 and make sure that your definition of IMAP_ADDR uses the same value
5309 as your U-Boot configuration in CONFIG_SYS_IMMR.
5312 Configuring the Linux kernel:
5313 -----------------------------
5315 No specific requirements for U-Boot. Make sure you have some root
5316 device (initial ramdisk, NFS) for your target system.
5319 Building a Linux Image:
5320 -----------------------
5322 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5323 not used. If you use recent kernel source, a new build target
5324 "uImage" will exist which automatically builds an image usable by
5325 U-Boot. Most older kernels also have support for a "pImage" target,
5326 which was introduced for our predecessor project PPCBoot and uses a
5327 100% compatible format.
5336 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5337 encapsulate a compressed Linux kernel image with header information,
5338 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5340 * build a standard "vmlinux" kernel image (in ELF binary format):
5342 * convert the kernel into a raw binary image:
5344 ${CROSS_COMPILE}-objcopy -O binary \
5345 -R .note -R .comment \
5346 -S vmlinux linux.bin
5348 * compress the binary image:
5352 * package compressed binary image for U-Boot:
5354 mkimage -A ppc -O linux -T kernel -C gzip \
5355 -a 0 -e 0 -n "Linux Kernel Image" \
5356 -d linux.bin.gz uImage
5359 The "mkimage" tool can also be used to create ramdisk images for use
5360 with U-Boot, either separated from the Linux kernel image, or
5361 combined into one file. "mkimage" encapsulates the images with a 64
5362 byte header containing information about target architecture,
5363 operating system, image type, compression method, entry points, time
5364 stamp, CRC32 checksums, etc.
5366 "mkimage" can be called in two ways: to verify existing images and
5367 print the header information, or to build new images.
5369 In the first form (with "-l" option) mkimage lists the information
5370 contained in the header of an existing U-Boot image; this includes
5371 checksum verification:
5373 tools/mkimage -l image
5374 -l ==> list image header information
5376 The second form (with "-d" option) is used to build a U-Boot image
5377 from a "data file" which is used as image payload:
5379 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5380 -n name -d data_file image
5381 -A ==> set architecture to 'arch'
5382 -O ==> set operating system to 'os'
5383 -T ==> set image type to 'type'
5384 -C ==> set compression type 'comp'
5385 -a ==> set load address to 'addr' (hex)
5386 -e ==> set entry point to 'ep' (hex)
5387 -n ==> set image name to 'name'
5388 -d ==> use image data from 'datafile'
5390 Right now, all Linux kernels for PowerPC systems use the same load
5391 address (0x00000000), but the entry point address depends on the
5394 - 2.2.x kernels have the entry point at 0x0000000C,
5395 - 2.3.x and later kernels have the entry point at 0x00000000.
5397 So a typical call to build a U-Boot image would read:
5399 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5400 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5401 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5402 > examples/uImage.TQM850L
5403 Image Name: 2.4.4 kernel for TQM850L
5404 Created: Wed Jul 19 02:34:59 2000
5405 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5406 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5407 Load Address: 0x00000000
5408 Entry Point: 0x00000000
5410 To verify the contents of the image (or check for corruption):
5412 -> tools/mkimage -l examples/uImage.TQM850L
5413 Image Name: 2.4.4 kernel for TQM850L
5414 Created: Wed Jul 19 02:34:59 2000
5415 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5416 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5417 Load Address: 0x00000000
5418 Entry Point: 0x00000000
5420 NOTE: for embedded systems where boot time is critical you can trade
5421 speed for memory and install an UNCOMPRESSED image instead: this
5422 needs more space in Flash, but boots much faster since it does not
5423 need to be uncompressed:
5425 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5426 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5427 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5428 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5429 > examples/uImage.TQM850L-uncompressed
5430 Image Name: 2.4.4 kernel for TQM850L
5431 Created: Wed Jul 19 02:34:59 2000
5432 Image Type: PowerPC Linux Kernel Image (uncompressed)
5433 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5434 Load Address: 0x00000000
5435 Entry Point: 0x00000000
5438 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5439 when your kernel is intended to use an initial ramdisk:
5441 -> tools/mkimage -n 'Simple Ramdisk Image' \
5442 > -A ppc -O linux -T ramdisk -C gzip \
5443 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5444 Image Name: Simple Ramdisk Image
5445 Created: Wed Jan 12 14:01:50 2000
5446 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5447 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5448 Load Address: 0x00000000
5449 Entry Point: 0x00000000
5451 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5452 option performs the converse operation of the mkimage's second form (the "-d"
5453 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5456 tools/dumpimage -i image -p position data_file
5457 -i ==> extract from the 'image' a specific 'data_file', \
5458 indexed by 'position'
5461 Installing a Linux Image:
5462 -------------------------
5464 To downloading a U-Boot image over the serial (console) interface,
5465 you must convert the image to S-Record format:
5467 objcopy -I binary -O srec examples/image examples/image.srec
5469 The 'objcopy' does not understand the information in the U-Boot
5470 image header, so the resulting S-Record file will be relative to
5471 address 0x00000000. To load it to a given address, you need to
5472 specify the target address as 'offset' parameter with the 'loads'
5475 Example: install the image to address 0x40100000 (which on the
5476 TQM8xxL is in the first Flash bank):
5478 => erase 40100000 401FFFFF
5484 ## Ready for S-Record download ...
5485 ~>examples/image.srec
5486 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5488 15989 15990 15991 15992
5489 [file transfer complete]
5491 ## Start Addr = 0x00000000
5494 You can check the success of the download using the 'iminfo' command;
5495 this includes a checksum verification so you can be sure no data
5496 corruption happened:
5500 ## Checking Image at 40100000 ...
5501 Image Name: 2.2.13 for initrd on TQM850L
5502 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5503 Data Size: 335725 Bytes = 327 kB = 0 MB
5504 Load Address: 00000000
5505 Entry Point: 0000000c
5506 Verifying Checksum ... OK
5512 The "bootm" command is used to boot an application that is stored in
5513 memory (RAM or Flash). In case of a Linux kernel image, the contents
5514 of the "bootargs" environment variable is passed to the kernel as
5515 parameters. You can check and modify this variable using the
5516 "printenv" and "setenv" commands:
5519 => printenv bootargs
5520 bootargs=root=/dev/ram
5522 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5524 => printenv bootargs
5525 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5528 ## Booting Linux kernel at 40020000 ...
5529 Image Name: 2.2.13 for NFS on TQM850L
5530 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5531 Data Size: 381681 Bytes = 372 kB = 0 MB
5532 Load Address: 00000000
5533 Entry Point: 0000000c
5534 Verifying Checksum ... OK
5535 Uncompressing Kernel Image ... OK
5536 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
5537 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5538 time_init: decrementer frequency = 187500000/60
5539 Calibrating delay loop... 49.77 BogoMIPS
5540 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5543 If you want to boot a Linux kernel with initial RAM disk, you pass
5544 the memory addresses of both the kernel and the initrd image (PPBCOOT
5545 format!) to the "bootm" command:
5547 => imi 40100000 40200000
5549 ## Checking Image at 40100000 ...
5550 Image Name: 2.2.13 for initrd on TQM850L
5551 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5552 Data Size: 335725 Bytes = 327 kB = 0 MB
5553 Load Address: 00000000
5554 Entry Point: 0000000c
5555 Verifying Checksum ... OK
5557 ## Checking Image at 40200000 ...
5558 Image Name: Simple Ramdisk Image
5559 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5560 Data Size: 566530 Bytes = 553 kB = 0 MB
5561 Load Address: 00000000
5562 Entry Point: 00000000
5563 Verifying Checksum ... OK
5565 => bootm 40100000 40200000
5566 ## Booting Linux kernel at 40100000 ...
5567 Image Name: 2.2.13 for initrd on TQM850L
5568 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5569 Data Size: 335725 Bytes = 327 kB = 0 MB
5570 Load Address: 00000000
5571 Entry Point: 0000000c
5572 Verifying Checksum ... OK
5573 Uncompressing Kernel Image ... OK
5574 ## Loading RAMDisk Image at 40200000 ...
5575 Image Name: Simple Ramdisk Image
5576 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5577 Data Size: 566530 Bytes = 553 kB = 0 MB
5578 Load Address: 00000000
5579 Entry Point: 00000000
5580 Verifying Checksum ... OK
5581 Loading Ramdisk ... OK
5582 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
5583 Boot arguments: root=/dev/ram
5584 time_init: decrementer frequency = 187500000/60
5585 Calibrating delay loop... 49.77 BogoMIPS
5587 RAMDISK: Compressed image found at block 0
5588 VFS: Mounted root (ext2 filesystem).
5592 Boot Linux and pass a flat device tree:
5595 First, U-Boot must be compiled with the appropriate defines. See the section
5596 titled "Linux Kernel Interface" above for a more in depth explanation. The
5597 following is an example of how to start a kernel and pass an updated
5603 oft=oftrees/mpc8540ads.dtb
5604 => tftp $oftaddr $oft
5605 Speed: 1000, full duplex
5607 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5608 Filename 'oftrees/mpc8540ads.dtb'.
5609 Load address: 0x300000
5612 Bytes transferred = 4106 (100a hex)
5613 => tftp $loadaddr $bootfile
5614 Speed: 1000, full duplex
5616 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5618 Load address: 0x200000
5619 Loading:############
5621 Bytes transferred = 1029407 (fb51f hex)
5626 => bootm $loadaddr - $oftaddr
5627 ## Booting image at 00200000 ...
5628 Image Name: Linux-2.6.17-dirty
5629 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5630 Data Size: 1029343 Bytes = 1005.2 kB
5631 Load Address: 00000000
5632 Entry Point: 00000000
5633 Verifying Checksum ... OK
5634 Uncompressing Kernel Image ... OK
5635 Booting using flat device tree at 0x300000
5636 Using MPC85xx ADS machine description
5637 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5641 More About U-Boot Image Types:
5642 ------------------------------
5644 U-Boot supports the following image types:
5646 "Standalone Programs" are directly runnable in the environment
5647 provided by U-Boot; it is expected that (if they behave
5648 well) you can continue to work in U-Boot after return from
5649 the Standalone Program.
5650 "OS Kernel Images" are usually images of some Embedded OS which
5651 will take over control completely. Usually these programs
5652 will install their own set of exception handlers, device
5653 drivers, set up the MMU, etc. - this means, that you cannot
5654 expect to re-enter U-Boot except by resetting the CPU.
5655 "RAMDisk Images" are more or less just data blocks, and their
5656 parameters (address, size) are passed to an OS kernel that is
5658 "Multi-File Images" contain several images, typically an OS
5659 (Linux) kernel image and one or more data images like
5660 RAMDisks. This construct is useful for instance when you want
5661 to boot over the network using BOOTP etc., where the boot
5662 server provides just a single image file, but you want to get
5663 for instance an OS kernel and a RAMDisk image.
5665 "Multi-File Images" start with a list of image sizes, each
5666 image size (in bytes) specified by an "uint32_t" in network
5667 byte order. This list is terminated by an "(uint32_t)0".
5668 Immediately after the terminating 0 follow the images, one by
5669 one, all aligned on "uint32_t" boundaries (size rounded up to
5670 a multiple of 4 bytes).
5672 "Firmware Images" are binary images containing firmware (like
5673 U-Boot or FPGA images) which usually will be programmed to
5676 "Script files" are command sequences that will be executed by
5677 U-Boot's command interpreter; this feature is especially
5678 useful when you configure U-Boot to use a real shell (hush)
5679 as command interpreter.
5681 Booting the Linux zImage:
5682 -------------------------
5684 On some platforms, it's possible to boot Linux zImage. This is done
5685 using the "bootz" command. The syntax of "bootz" command is the same
5686 as the syntax of "bootm" command.
5688 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5689 kernel with raw initrd images. The syntax is slightly different, the
5690 address of the initrd must be augmented by it's size, in the following
5691 format: "<initrd addres>:<initrd size>".
5697 One of the features of U-Boot is that you can dynamically load and
5698 run "standalone" applications, which can use some resources of
5699 U-Boot like console I/O functions or interrupt services.
5701 Two simple examples are included with the sources:
5706 'examples/hello_world.c' contains a small "Hello World" Demo
5707 application; it is automatically compiled when you build U-Boot.
5708 It's configured to run at address 0x00040004, so you can play with it
5712 ## Ready for S-Record download ...
5713 ~>examples/hello_world.srec
5714 1 2 3 4 5 6 7 8 9 10 11 ...
5715 [file transfer complete]
5717 ## Start Addr = 0x00040004
5719 => go 40004 Hello World! This is a test.
5720 ## Starting application at 0x00040004 ...
5731 Hit any key to exit ...
5733 ## Application terminated, rc = 0x0
5735 Another example, which demonstrates how to register a CPM interrupt
5736 handler with the U-Boot code, can be found in 'examples/timer.c'.
5737 Here, a CPM timer is set up to generate an interrupt every second.
5738 The interrupt service routine is trivial, just printing a '.'
5739 character, but this is just a demo program. The application can be
5740 controlled by the following keys:
5742 ? - print current values og the CPM Timer registers
5743 b - enable interrupts and start timer
5744 e - stop timer and disable interrupts
5745 q - quit application
5748 ## Ready for S-Record download ...
5749 ~>examples/timer.srec
5750 1 2 3 4 5 6 7 8 9 10 11 ...
5751 [file transfer complete]
5753 ## Start Addr = 0x00040004
5756 ## Starting application at 0x00040004 ...
5759 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5762 [q, b, e, ?] Set interval 1000000 us
5765 [q, b, e, ?] ........
5766 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5769 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5772 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5775 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5777 [q, b, e, ?] ...Stopping timer
5779 [q, b, e, ?] ## Application terminated, rc = 0x0
5785 Over time, many people have reported problems when trying to use the
5786 "minicom" terminal emulation program for serial download. I (wd)
5787 consider minicom to be broken, and recommend not to use it. Under
5788 Unix, I recommend to use C-Kermit for general purpose use (and
5789 especially for kermit binary protocol download ("loadb" command), and
5790 use "cu" for S-Record download ("loads" command). See
5791 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5792 for help with kermit.
5795 Nevertheless, if you absolutely want to use it try adding this
5796 configuration to your "File transfer protocols" section:
5798 Name Program Name U/D FullScr IO-Red. Multi
5799 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5800 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5806 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5807 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5809 Building requires a cross environment; it is known to work on
5810 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5811 need gmake since the Makefiles are not compatible with BSD make).
5812 Note that the cross-powerpc package does not install include files;
5813 attempting to build U-Boot will fail because <machine/ansi.h> is
5814 missing. This file has to be installed and patched manually:
5816 # cd /usr/pkg/cross/powerpc-netbsd/include
5818 # ln -s powerpc machine
5819 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5820 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5822 Native builds *don't* work due to incompatibilities between native
5823 and U-Boot include files.
5825 Booting assumes that (the first part of) the image booted is a
5826 stage-2 loader which in turn loads and then invokes the kernel
5827 proper. Loader sources will eventually appear in the NetBSD source
5828 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5829 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5832 Implementation Internals:
5833 =========================
5835 The following is not intended to be a complete description of every
5836 implementation detail. However, it should help to understand the
5837 inner workings of U-Boot and make it easier to port it to custom
5841 Initial Stack, Global Data:
5842 ---------------------------
5844 The implementation of U-Boot is complicated by the fact that U-Boot
5845 starts running out of ROM (flash memory), usually without access to
5846 system RAM (because the memory controller is not initialized yet).
5847 This means that we don't have writable Data or BSS segments, and BSS
5848 is not initialized as zero. To be able to get a C environment working
5849 at all, we have to allocate at least a minimal stack. Implementation
5850 options for this are defined and restricted by the CPU used: Some CPU
5851 models provide on-chip memory (like the IMMR area on MPC8xx and
5852 MPC826x processors), on others (parts of) the data cache can be
5853 locked as (mis-) used as memory, etc.
5855 Chris Hallinan posted a good summary of these issues to the
5856 U-Boot mailing list:
5858 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5859 From: "Chris Hallinan" <clh@net1plus.com>
5860 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5863 Correct me if I'm wrong, folks, but the way I understand it
5864 is this: Using DCACHE as initial RAM for Stack, etc, does not
5865 require any physical RAM backing up the cache. The cleverness
5866 is that the cache is being used as a temporary supply of
5867 necessary storage before the SDRAM controller is setup. It's
5868 beyond the scope of this list to explain the details, but you
5869 can see how this works by studying the cache architecture and
5870 operation in the architecture and processor-specific manuals.
5872 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5873 is another option for the system designer to use as an
5874 initial stack/RAM area prior to SDRAM being available. Either
5875 option should work for you. Using CS 4 should be fine if your
5876 board designers haven't used it for something that would
5877 cause you grief during the initial boot! It is frequently not
5880 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5881 with your processor/board/system design. The default value
5882 you will find in any recent u-boot distribution in
5883 walnut.h should work for you. I'd set it to a value larger
5884 than your SDRAM module. If you have a 64MB SDRAM module, set
5885 it above 400_0000. Just make sure your board has no resources
5886 that are supposed to respond to that address! That code in
5887 start.S has been around a while and should work as is when
5888 you get the config right.
5893 It is essential to remember this, since it has some impact on the C
5894 code for the initialization procedures:
5896 * Initialized global data (data segment) is read-only. Do not attempt
5899 * Do not use any uninitialized global data (or implicitely initialized
5900 as zero data - BSS segment) at all - this is undefined, initiali-
5901 zation is performed later (when relocating to RAM).
5903 * Stack space is very limited. Avoid big data buffers or things like
5906 Having only the stack as writable memory limits means we cannot use
5907 normal global data to share information beween the code. But it
5908 turned out that the implementation of U-Boot can be greatly
5909 simplified by making a global data structure (gd_t) available to all
5910 functions. We could pass a pointer to this data as argument to _all_
5911 functions, but this would bloat the code. Instead we use a feature of
5912 the GCC compiler (Global Register Variables) to share the data: we
5913 place a pointer (gd) to the global data into a register which we
5914 reserve for this purpose.
5916 When choosing a register for such a purpose we are restricted by the
5917 relevant (E)ABI specifications for the current architecture, and by
5918 GCC's implementation.
5920 For PowerPC, the following registers have specific use:
5922 R2: reserved for system use
5923 R3-R4: parameter passing and return values
5924 R5-R10: parameter passing
5925 R13: small data area pointer
5929 (U-Boot also uses R12 as internal GOT pointer. r12
5930 is a volatile register so r12 needs to be reset when
5931 going back and forth between asm and C)
5933 ==> U-Boot will use R2 to hold a pointer to the global data
5935 Note: on PPC, we could use a static initializer (since the
5936 address of the global data structure is known at compile time),
5937 but it turned out that reserving a register results in somewhat
5938 smaller code - although the code savings are not that big (on
5939 average for all boards 752 bytes for the whole U-Boot image,
5940 624 text + 127 data).
5942 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5943 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5945 ==> U-Boot will use P3 to hold a pointer to the global data
5947 On ARM, the following registers are used:
5949 R0: function argument word/integer result
5950 R1-R3: function argument word
5951 R9: platform specific
5952 R10: stack limit (used only if stack checking is enabled)
5953 R11: argument (frame) pointer
5954 R12: temporary workspace
5957 R15: program counter
5959 ==> U-Boot will use R9 to hold a pointer to the global data
5961 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5963 On Nios II, the ABI is documented here:
5964 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5966 ==> U-Boot will use gp to hold a pointer to the global data
5968 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5969 to access small data sections, so gp is free.
5971 On NDS32, the following registers are used:
5973 R0-R1: argument/return
5975 R15: temporary register for assembler
5976 R16: trampoline register
5977 R28: frame pointer (FP)
5978 R29: global pointer (GP)
5979 R30: link register (LP)
5980 R31: stack pointer (SP)
5981 PC: program counter (PC)
5983 ==> U-Boot will use R10 to hold a pointer to the global data
5985 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5986 or current versions of GCC may "optimize" the code too much.
5991 U-Boot runs in system state and uses physical addresses, i.e. the
5992 MMU is not used either for address mapping nor for memory protection.
5994 The available memory is mapped to fixed addresses using the memory
5995 controller. In this process, a contiguous block is formed for each
5996 memory type (Flash, SDRAM, SRAM), even when it consists of several
5997 physical memory banks.
5999 U-Boot is installed in the first 128 kB of the first Flash bank (on
6000 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6001 booting and sizing and initializing DRAM, the code relocates itself
6002 to the upper end of DRAM. Immediately below the U-Boot code some
6003 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6004 configuration setting]. Below that, a structure with global Board
6005 Info data is placed, followed by the stack (growing downward).
6007 Additionally, some exception handler code is copied to the low 8 kB
6008 of DRAM (0x00000000 ... 0x00001FFF).
6010 So a typical memory configuration with 16 MB of DRAM could look like
6013 0x0000 0000 Exception Vector code
6016 0x0000 2000 Free for Application Use
6022 0x00FB FF20 Monitor Stack (Growing downward)
6023 0x00FB FFAC Board Info Data and permanent copy of global data
6024 0x00FC 0000 Malloc Arena
6027 0x00FE 0000 RAM Copy of Monitor Code
6028 ... eventually: LCD or video framebuffer
6029 ... eventually: pRAM (Protected RAM - unchanged by reset)
6030 0x00FF FFFF [End of RAM]
6033 System Initialization:
6034 ----------------------
6036 In the reset configuration, U-Boot starts at the reset entry point
6037 (on most PowerPC systems at address 0x00000100). Because of the reset
6038 configuration for CS0# this is a mirror of the onboard Flash memory.
6039 To be able to re-map memory U-Boot then jumps to its link address.
6040 To be able to implement the initialization code in C, a (small!)
6041 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6042 which provide such a feature like MPC8xx or MPC8260), or in a locked
6043 part of the data cache. After that, U-Boot initializes the CPU core,
6044 the caches and the SIU.
6046 Next, all (potentially) available memory banks are mapped using a
6047 preliminary mapping. For example, we put them on 512 MB boundaries
6048 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6049 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6050 programmed for SDRAM access. Using the temporary configuration, a
6051 simple memory test is run that determines the size of the SDRAM
6054 When there is more than one SDRAM bank, and the banks are of
6055 different size, the largest is mapped first. For equal size, the first
6056 bank (CS2#) is mapped first. The first mapping is always for address
6057 0x00000000, with any additional banks following immediately to create
6058 contiguous memory starting from 0.
6060 Then, the monitor installs itself at the upper end of the SDRAM area
6061 and allocates memory for use by malloc() and for the global Board
6062 Info data; also, the exception vector code is copied to the low RAM
6063 pages, and the final stack is set up.
6065 Only after this relocation will you have a "normal" C environment;
6066 until that you are restricted in several ways, mostly because you are
6067 running from ROM, and because the code will have to be relocated to a
6071 U-Boot Porting Guide:
6072 ----------------------
6074 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6078 int main(int argc, char *argv[])
6080 sighandler_t no_more_time;
6082 signal(SIGALRM, no_more_time);
6083 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6085 if (available_money > available_manpower) {
6086 Pay consultant to port U-Boot;
6090 Download latest U-Boot source;
6092 Subscribe to u-boot mailing list;
6095 email("Hi, I am new to U-Boot, how do I get started?");
6098 Read the README file in the top level directory;
6099 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6100 Read applicable doc/*.README;
6101 Read the source, Luke;
6102 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6105 if (available_money > toLocalCurrency ($2500))
6108 Add a lot of aggravation and time;
6110 if (a similar board exists) { /* hopefully... */
6111 cp -a board/<similar> board/<myboard>
6112 cp include/configs/<similar>.h include/configs/<myboard>.h
6114 Create your own board support subdirectory;
6115 Create your own board include/configs/<myboard>.h file;
6117 Edit new board/<myboard> files
6118 Edit new include/configs/<myboard>.h
6123 Add / modify source code;
6127 email("Hi, I am having problems...");
6129 Send patch file to the U-Boot email list;
6130 if (reasonable critiques)
6131 Incorporate improvements from email list code review;
6133 Defend code as written;
6139 void no_more_time (int sig)
6148 All contributions to U-Boot should conform to the Linux kernel
6149 coding style; see the file "Documentation/CodingStyle" and the script
6150 "scripts/Lindent" in your Linux kernel source directory.
6152 Source files originating from a different project (for example the
6153 MTD subsystem) are generally exempt from these guidelines and are not
6154 reformated to ease subsequent migration to newer versions of those
6157 Please note that U-Boot is implemented in C (and to some small parts in
6158 Assembler); no C++ is used, so please do not use C++ style comments (//)
6161 Please also stick to the following formatting rules:
6162 - remove any trailing white space
6163 - use TAB characters for indentation and vertical alignment, not spaces
6164 - make sure NOT to use DOS '\r\n' line feeds
6165 - do not add more than 2 consecutive empty lines to source files
6166 - do not add trailing empty lines to source files
6168 Submissions which do not conform to the standards may be returned
6169 with a request to reformat the changes.
6175 Since the number of patches for U-Boot is growing, we need to
6176 establish some rules. Submissions which do not conform to these rules
6177 may be rejected, even when they contain important and valuable stuff.
6179 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6181 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6182 see http://lists.denx.de/mailman/listinfo/u-boot
6184 When you send a patch, please include the following information with
6187 * For bug fixes: a description of the bug and how your patch fixes
6188 this bug. Please try to include a way of demonstrating that the
6189 patch actually fixes something.
6191 * For new features: a description of the feature and your
6194 * A CHANGELOG entry as plaintext (separate from the patch)
6196 * For major contributions, your entry to the CREDITS file
6198 * When you add support for a new board, don't forget to add a
6199 maintainer e-mail address to the boards.cfg file, too.
6201 * If your patch adds new configuration options, don't forget to
6202 document these in the README file.
6204 * The patch itself. If you are using git (which is *strongly*
6205 recommended) you can easily generate the patch using the
6206 "git format-patch". If you then use "git send-email" to send it to
6207 the U-Boot mailing list, you will avoid most of the common problems
6208 with some other mail clients.
6210 If you cannot use git, use "diff -purN OLD NEW". If your version of
6211 diff does not support these options, then get the latest version of
6214 The current directory when running this command shall be the parent
6215 directory of the U-Boot source tree (i. e. please make sure that
6216 your patch includes sufficient directory information for the
6219 We prefer patches as plain text. MIME attachments are discouraged,
6220 and compressed attachments must not be used.
6222 * If one logical set of modifications affects or creates several
6223 files, all these changes shall be submitted in a SINGLE patch file.
6225 * Changesets that contain different, unrelated modifications shall be
6226 submitted as SEPARATE patches, one patch per changeset.
6231 * Before sending the patch, run the MAKEALL script on your patched
6232 source tree and make sure that no errors or warnings are reported
6233 for any of the boards.
6235 * Keep your modifications to the necessary minimum: A patch
6236 containing several unrelated changes or arbitrary reformats will be
6237 returned with a request to re-formatting / split it.
6239 * If you modify existing code, make sure that your new code does not
6240 add to the memory footprint of the code ;-) Small is beautiful!
6241 When adding new features, these should compile conditionally only
6242 (using #ifdef), and the resulting code with the new feature
6243 disabled must not need more memory than the old code without your
6246 * Remember that there is a size limit of 100 kB per message on the
6247 u-boot mailing list. Bigger patches will be moderated. If they are
6248 reasonable and not too big, they will be acknowledged. But patches
6249 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob