2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
186 /mpc5xx Files specific to Freescale MPC5xx CPUs
187 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
188 /mpc8xx Files specific to Freescale MPC8xx CPUs
189 /mpc824x Files specific to Freescale MPC824x CPUs
190 /mpc8260 Files specific to Freescale MPC8260 CPUs
191 /mpc85xx Files specific to Freescale MPC85xx CPUs
192 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
193 /lib Architecture specific library files
194 /sh Files generic to SH architecture
195 /cpu CPU specific files
196 /sh2 Files specific to sh2 CPUs
197 /sh3 Files specific to sh3 CPUs
198 /sh4 Files specific to sh4 CPUs
199 /lib Architecture specific library files
200 /sparc Files generic to SPARC architecture
201 /cpu CPU specific files
202 /leon2 Files specific to Gaisler LEON2 SPARC CPU
203 /leon3 Files specific to Gaisler LEON3 SPARC CPU
204 /lib Architecture specific library files
205 /x86 Files generic to x86 architecture
206 /cpu CPU specific files
207 /lib Architecture specific library files
208 /api Machine/arch independent API for external apps
209 /board Board dependent files
210 /common Misc architecture independent functions
211 /disk Code for disk drive partition handling
212 /doc Documentation (don't expect too much)
213 /drivers Commonly used device drivers
214 /dts Contains Makefile for building internal U-Boot fdt.
215 /examples Example code for standalone applications, etc.
216 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
217 /include Header Files
218 /lib Files generic to all architectures
219 /libfdt Library files to support flattened device trees
220 /lzma Library files to support LZMA decompression
221 /lzo Library files to support LZO decompression
223 /post Power On Self Test
224 /spl Secondary Program Loader framework
225 /tools Tools to build S-Record or U-Boot images, etc.
227 Software Configuration:
228 =======================
230 Configuration is usually done using C preprocessor defines; the
231 rationale behind that is to avoid dead code whenever possible.
233 There are two classes of configuration variables:
235 * Configuration _OPTIONS_:
236 These are selectable by the user and have names beginning with
239 * Configuration _SETTINGS_:
240 These depend on the hardware etc. and should not be meddled with if
241 you don't know what you're doing; they have names beginning with
244 Later we will add a configuration tool - probably similar to or even
245 identical to what's used for the Linux kernel. Right now, we have to
246 do the configuration by hand, which means creating some symbolic
247 links and editing some configuration files. We use the TQM8xxL boards
251 Selection of Processor Architecture and Board Type:
252 ---------------------------------------------------
254 For all supported boards there are ready-to-use default
255 configurations available; just type "make <board_name>_config".
257 Example: For a TQM823L module type:
262 For the Cogent platform, you need to specify the CPU type as well;
263 e.g. "make cogent_mpc8xx_config". And also configure the cogent
264 directory according to the instructions in cogent/README.
270 U-Boot can be built natively to run on a Linux host using the 'sandbox'
271 board. This allows feature development which is not board- or architecture-
272 specific to be undertaken on a native platform. The sandbox is also used to
273 run some of U-Boot's tests.
275 See board/sandbox/sandbox/README.sandbox for more details.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Marvell Family Member
325 CONFIG_SYS_MVFS - define it if you want to enable
326 multiple fs option at one time
327 for marvell soc family
329 - MPC824X Family Member (if CONFIG_MPC824X is defined)
330 Define exactly one of
331 CONFIG_MPC8240, CONFIG_MPC8245
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_PPC_E500_DEBUG_TLB
381 Enables a temporary TLB entry to be used during boot to work
382 around limitations in e500v1 and e500v2 external debugger
383 support. This reduces the portions of the boot code where
384 breakpoints and single stepping do not work. The value of this
385 symbol should be set to the TLB1 entry to be used for this
388 CONFIG_SYS_FSL_ERRATUM_A004510
390 Enables a workaround for erratum A004510. If set,
391 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
394 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
397 Defines one or two SoC revisions (low 8 bits of SVR)
398 for which the A004510 workaround should be applied.
400 The rest of SVR is either not relevant to the decision
401 of whether the erratum is present (e.g. p2040 versus
402 p2041) or is implied by the build target, which controls
403 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
405 See Freescale App Note 4493 for more information about
408 CONFIG_A003399_NOR_WORKAROUND
409 Enables a workaround for IFC erratum A003399. It is only
410 requred during NOR boot.
412 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
414 This is the value to write into CCSR offset 0x18600
415 according to the A004510 workaround.
417 CONFIG_SYS_FSL_DSP_DDR_ADDR
418 This value denotes start offset of DDR memory which is
419 connected exclusively to the DSP cores.
421 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
422 This value denotes start offset of M2 memory
423 which is directly connected to the DSP core.
425 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
426 This value denotes start offset of M3 memory which is directly
427 connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430 This value denotes start offset of DSP CCSR space.
432 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
433 Single Source Clock is clocking mode present in some of FSL SoC's.
434 In this mode, a single differential clock is used to supply
435 clocks to the sysclock, ddrclock and usbclock.
437 CONFIG_SYS_CPC_REINIT_F
438 This CONFIG is defined when the CPC is configured as SRAM at the
439 time of U-boot entry and is required to be re-initialized.
442 Inidcates this SoC supports deep sleep feature. If deep sleep is
443 supported, core will start to execute uboot when wakes up.
445 - Generic CPU options:
446 CONFIG_SYS_GENERIC_GLOBAL_DATA
447 Defines global data is initialized in generic board board_init_f().
448 If this macro is defined, global data is created and cleared in
449 generic board board_init_f(). Without this macro, architecture/board
450 should initialize global data before calling board_init_f().
452 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
454 Defines the endianess of the CPU. Implementation of those
455 values is arch specific.
458 Freescale DDR driver in use. This type of DDR controller is
459 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
462 CONFIG_SYS_FSL_DDR_ADDR
463 Freescale DDR memory-mapped register base.
465 CONFIG_SYS_FSL_DDR_EMU
466 Specify emulator support for DDR. Some DDR features such as
467 deskew training are not available.
469 CONFIG_SYS_FSL_DDRC_GEN1
470 Freescale DDR1 controller.
472 CONFIG_SYS_FSL_DDRC_GEN2
473 Freescale DDR2 controller.
475 CONFIG_SYS_FSL_DDRC_GEN3
476 Freescale DDR3 controller.
478 CONFIG_SYS_FSL_DDRC_GEN4
479 Freescale DDR4 controller.
481 CONFIG_SYS_FSL_DDRC_ARM_GEN3
482 Freescale DDR3 controller for ARM-based SoCs.
485 Board config to use DDR1. It can be enabled for SoCs with
486 Freescale DDR1 or DDR2 controllers, depending on the board
490 Board config to use DDR2. It can be eanbeld for SoCs with
491 Freescale DDR2 or DDR3 controllers, depending on the board
495 Board config to use DDR3. It can be enabled for SoCs with
496 Freescale DDR3 or DDR3L controllers.
499 Board config to use DDR3L. It can be enabled for SoCs with
503 Board config to use DDR4. It can be enabled for SoCs with
506 CONFIG_SYS_FSL_IFC_BE
507 Defines the IFC controller register space as Big Endian
509 CONFIG_SYS_FSL_IFC_LE
510 Defines the IFC controller register space as Little Endian
512 CONFIG_SYS_FSL_PBL_PBI
513 It enables addition of RCW (Power on reset configuration) in built image.
514 Please refer doc/README.pblimage for more details
516 CONFIG_SYS_FSL_PBL_RCW
517 It adds PBI(pre-boot instructions) commands in u-boot build image.
518 PBI commands can be used to configure SoC before it starts the execution.
519 Please refer doc/README.pblimage for more details
522 It adds a target to create boot binary having SPL binary in PBI format
523 concatenated with u-boot binary.
525 CONFIG_SYS_FSL_DDR_BE
526 Defines the DDR controller register space as Big Endian
528 CONFIG_SYS_FSL_DDR_LE
529 Defines the DDR controller register space as Little Endian
531 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532 Physical address from the view of DDR controllers. It is the
533 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
534 it could be different for ARM SoCs.
536 CONFIG_SYS_FSL_DDR_INTLV_256B
537 DDR controller interleaving on 256-byte. This is a special
538 interleaving mode, handled by Dickens for Freescale layerscape
541 - Intel Monahans options:
542 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
544 Defines the Monahans run mode to oscillator
545 ratio. Valid values are 8, 16, 24, 31. The core
546 frequency is this value multiplied by 13 MHz.
548 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
550 Defines the Monahans turbo mode to oscillator
551 ratio. Valid values are 1 (default if undefined) and
552 2. The core frequency as calculated above is multiplied
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
593 CONFIG_SYS_THUMB_BUILD
595 Use this flag to build U-Boot using the Thumb instruction
596 set for ARM architectures. Thumb instruction set provides
597 better code density. For ARM architectures that support
598 Thumb2 this flag will result in Thumb2 code generated by
601 CONFIG_ARM_ERRATA_716044
602 CONFIG_ARM_ERRATA_742230
603 CONFIG_ARM_ERRATA_743622
604 CONFIG_ARM_ERRATA_751472
605 CONFIG_ARM_ERRATA_794072
606 CONFIG_ARM_ERRATA_761320
608 If set, the workarounds for these ARM errata are applied early
609 during U-Boot startup. Note that these options force the
610 workarounds to be applied; no CPU-type/version detection
611 exists, unlike the similar options in the Linux kernel. Do not
612 set these options unless they apply!
617 The frequency of the timer returned by get_timer().
618 get_timer() must operate in milliseconds and this CONFIG
619 option must be set to 1000.
621 - Linux Kernel Interface:
624 U-Boot stores all clock information in Hz
625 internally. For binary compatibility with older Linux
626 kernels (which expect the clocks passed in the
627 bd_info data to be in MHz) the environment variable
628 "clocks_in_mhz" can be defined so that U-Boot
629 converts clock data to MHZ before passing it to the
631 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
632 "clocks_in_mhz=1" is automatically included in the
635 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
637 When transferring memsize parameter to linux, some versions
638 expect it to be in bytes, others in MB.
639 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
643 New kernel versions are expecting firmware settings to be
644 passed using flattened device trees (based on open firmware
648 * New libfdt-based support
649 * Adds the "fdt" command
650 * The bootm command automatically updates the fdt
652 OF_CPU - The proper name of the cpus node (only required for
653 MPC512X and MPC5xxx based boards).
654 OF_SOC - The proper name of the soc node (only required for
655 MPC512X and MPC5xxx based boards).
656 OF_TBCLK - The timebase frequency.
657 OF_STDOUT_PATH - The path to the console device
659 boards with QUICC Engines require OF_QE to set UCC MAC
662 CONFIG_OF_BOARD_SETUP
664 Board code has addition modification that it wants to make
665 to the flat device tree before handing it off to the kernel
669 This define fills in the correct boot CPU in the boot
670 param header, the default value is zero if undefined.
674 U-Boot can detect if an IDE device is present or not.
675 If not, and this new config option is activated, U-Boot
676 removes the ATA node from the DTS before booting Linux,
677 so the Linux IDE driver does not probe the device and
678 crash. This is needed for buggy hardware (uc101) where
679 no pull down resistor is connected to the signal IDE5V_DD7.
681 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
683 This setting is mandatory for all boards that have only one
684 machine type and must be used to specify the machine type
685 number as it appears in the ARM machine registry
686 (see http://www.arm.linux.org.uk/developer/machines/).
687 Only boards that have multiple machine types supported
688 in a single configuration file and the machine type is
689 runtime discoverable, do not have to use this setting.
691 - vxWorks boot parameters:
693 bootvx constructs a valid bootline using the following
694 environments variables: bootfile, ipaddr, serverip, hostname.
695 It loads the vxWorks image pointed bootfile.
697 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
698 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
699 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
700 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
702 CONFIG_SYS_VXWORKS_ADD_PARAMS
704 Add it at the end of the bootline. E.g "u=username pw=secret"
706 Note: If a "bootargs" environment is defined, it will overwride
707 the defaults discussed just above.
709 - Cache Configuration:
710 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
711 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
712 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
714 - Cache Configuration for ARM:
715 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
717 CONFIG_SYS_PL310_BASE - Physical base address of PL310
718 controller register space
723 Define this if you want support for Amba PrimeCell PL010 UARTs.
727 Define this if you want support for Amba PrimeCell PL011 UARTs.
731 If you have Amba PrimeCell PL011 UARTs, set this variable to
732 the clock speed of the UARTs.
736 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
737 define this to a list of base addresses for each (supported)
738 port. See e.g. include/configs/versatile.h
740 CONFIG_PL011_SERIAL_RLCR
742 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
743 have separate receive and transmit line control registers. Set
744 this variable to initialize the extra register.
746 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
748 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
749 boot loader that has already initialized the UART. Define this
750 variable to flush the UART at init time.
752 CONFIG_SERIAL_HW_FLOW_CONTROL
754 Define this variable to enable hw flow control in serial driver.
755 Current user of this option is drivers/serial/nsl16550.c driver
758 Depending on board, define exactly one serial port
759 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
760 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
761 console by defining CONFIG_8xx_CONS_NONE
763 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
764 port routines must be defined elsewhere
765 (i.e. serial_init(), serial_getc(), ...)
768 Enables console device for a color framebuffer. Needs following
769 defines (cf. smiLynxEM, i8042)
770 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
772 VIDEO_HW_RECTFILL graphic chip supports
775 VIDEO_HW_BITBLT graphic chip supports
776 bit-blit (cf. smiLynxEM)
777 VIDEO_VISIBLE_COLS visible pixel columns
779 VIDEO_VISIBLE_ROWS visible pixel rows
780 VIDEO_PIXEL_SIZE bytes per pixel
781 VIDEO_DATA_FORMAT graphic data format
782 (0-5, cf. cfb_console.c)
783 VIDEO_FB_ADRS framebuffer address
784 VIDEO_KBD_INIT_FCT keyboard int fct
785 (i.e. i8042_kbd_init())
786 VIDEO_TSTC_FCT test char fct
788 VIDEO_GETC_FCT get char fct
790 CONFIG_CONSOLE_CURSOR cursor drawing on/off
791 (requires blink timer
793 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
794 CONFIG_CONSOLE_TIME display time/date info in
796 (requires CONFIG_CMD_DATE)
797 CONFIG_VIDEO_LOGO display Linux logo in
799 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
800 linux_logo.h for logo.
801 Requires CONFIG_VIDEO_LOGO
802 CONFIG_CONSOLE_EXTRA_INFO
803 additional board info beside
806 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
807 a limited number of ANSI escape sequences (cursor control,
808 erase functions and limited graphics rendition control).
810 When CONFIG_CFB_CONSOLE is defined, video console is
811 default i/o. Serial console can be forced with
812 environment 'console=serial'.
814 When CONFIG_SILENT_CONSOLE is defined, all console
815 messages (by U-Boot and Linux!) can be silenced with
816 the "silent" environment variable. See
817 doc/README.silent for more information.
819 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
821 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
825 CONFIG_BAUDRATE - in bps
826 Select one of the baudrates listed in
827 CONFIG_SYS_BAUDRATE_TABLE, see below.
828 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
830 - Console Rx buffer length
831 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
832 the maximum receive buffer length for the SMC.
833 This option is actual only for 82xx and 8xx possible.
834 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
835 must be defined, to setup the maximum idle timeout for
838 - Pre-Console Buffer:
839 Prior to the console being initialised (i.e. serial UART
840 initialised etc) all console output is silently discarded.
841 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
842 buffer any console messages prior to the console being
843 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
844 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
845 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
846 bytes are output before the console is initialised, the
847 earlier bytes are discarded.
849 'Sane' compilers will generate smaller code if
850 CONFIG_PRE_CON_BUF_SZ is a power of 2
852 - Safe printf() functions
853 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
854 the printf() functions. These are defined in
855 include/vsprintf.h and include snprintf(), vsnprintf() and
856 so on. Code size increase is approximately 300-500 bytes.
857 If this option is not given then these functions will
858 silently discard their buffer size argument - this means
859 you are not getting any overflow checking in this case.
861 - Boot Delay: CONFIG_BOOTDELAY - in seconds
862 Delay before automatically booting the default image;
863 set to -1 to disable autoboot.
864 set to -2 to autoboot with no delay and not check for abort
865 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
867 See doc/README.autoboot for these options that
868 work with CONFIG_BOOTDELAY. None are required.
869 CONFIG_BOOT_RETRY_TIME
870 CONFIG_BOOT_RETRY_MIN
871 CONFIG_AUTOBOOT_KEYED
872 CONFIG_AUTOBOOT_PROMPT
873 CONFIG_AUTOBOOT_DELAY_STR
874 CONFIG_AUTOBOOT_STOP_STR
875 CONFIG_AUTOBOOT_DELAY_STR2
876 CONFIG_AUTOBOOT_STOP_STR2
877 CONFIG_ZERO_BOOTDELAY_CHECK
878 CONFIG_RESET_TO_RETRY
882 Only needed when CONFIG_BOOTDELAY is enabled;
883 define a command string that is automatically executed
884 when no character is read on the console interface
885 within "Boot Delay" after reset.
888 This can be used to pass arguments to the bootm
889 command. The value of CONFIG_BOOTARGS goes into the
890 environment value "bootargs".
892 CONFIG_RAMBOOT and CONFIG_NFSBOOT
893 The value of these goes into the environment as
894 "ramboot" and "nfsboot" respectively, and can be used
895 as a convenience, when switching between booting from
899 CONFIG_BOOTCOUNT_LIMIT
900 Implements a mechanism for detecting a repeating reboot
902 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
905 If no softreset save registers are found on the hardware
906 "bootcount" is stored in the environment. To prevent a
907 saveenv on all reboots, the environment variable
908 "upgrade_available" is used. If "upgrade_available" is
909 0, "bootcount" is always 0, if "upgrade_available" is
910 1 "bootcount" is incremented in the environment.
911 So the Userspace Applikation must set the "upgrade_available"
912 and "bootcount" variable to 0, if a boot was successfully.
917 When this option is #defined, the existence of the
918 environment variable "preboot" will be checked
919 immediately before starting the CONFIG_BOOTDELAY
920 countdown and/or running the auto-boot command resp.
921 entering interactive mode.
923 This feature is especially useful when "preboot" is
924 automatically generated or modified. For an example
925 see the LWMON board specific code: here "preboot" is
926 modified when the user holds down a certain
927 combination of keys on the (special) keyboard when
930 - Serial Download Echo Mode:
932 If defined to 1, all characters received during a
933 serial download (using the "loads" command) are
934 echoed back. This might be needed by some terminal
935 emulations (like "cu"), but may as well just take
936 time on others. This setting #define's the initial
937 value of the "loads_echo" environment variable.
939 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
941 Select one of the baudrates listed in
942 CONFIG_SYS_BAUDRATE_TABLE, see below.
945 Monitor commands can be included or excluded
946 from the build by using the #include files
947 <config_cmd_all.h> and #undef'ing unwanted
948 commands, or using <config_cmd_default.h>
949 and augmenting with additional #define's
952 The default command configuration includes all commands
953 except those marked below with a "*".
955 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
956 CONFIG_CMD_ASKENV * ask for env variable
957 CONFIG_CMD_BDI bdinfo
958 CONFIG_CMD_BEDBUG * Include BedBug Debugger
959 CONFIG_CMD_BMP * BMP support
960 CONFIG_CMD_BSP * Board specific commands
961 CONFIG_CMD_BOOTD bootd
962 CONFIG_CMD_CACHE * icache, dcache
963 CONFIG_CMD_CLK * clock command support
964 CONFIG_CMD_CONSOLE coninfo
965 CONFIG_CMD_CRC32 * crc32
966 CONFIG_CMD_DATE * support for RTC, date/time...
967 CONFIG_CMD_DHCP * DHCP support
968 CONFIG_CMD_DIAG * Diagnostics
969 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
970 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
971 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
972 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
973 CONFIG_CMD_DTT * Digital Therm and Thermostat
974 CONFIG_CMD_ECHO echo arguments
975 CONFIG_CMD_EDITENV edit env variable
976 CONFIG_CMD_EEPROM * EEPROM read/write support
977 CONFIG_CMD_ELF * bootelf, bootvx
978 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
979 CONFIG_CMD_ENV_FLAGS * display details about env flags
980 CONFIG_CMD_ENV_EXISTS * check existence of env variable
981 CONFIG_CMD_EXPORTENV * export the environment
982 CONFIG_CMD_EXT2 * ext2 command support
983 CONFIG_CMD_EXT4 * ext4 command support
984 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
985 that work for multiple fs types
986 CONFIG_CMD_SAVEENV saveenv
987 CONFIG_CMD_FDC * Floppy Disk Support
988 CONFIG_CMD_FAT * FAT command support
989 CONFIG_CMD_FLASH flinfo, erase, protect
990 CONFIG_CMD_FPGA FPGA device initialization support
991 CONFIG_CMD_FUSE * Device fuse support
992 CONFIG_CMD_GETTIME * Get time since boot
993 CONFIG_CMD_GO * the 'go' command (exec code)
994 CONFIG_CMD_GREPENV * search environment
995 CONFIG_CMD_HASH * calculate hash / digest
996 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
997 CONFIG_CMD_I2C * I2C serial bus support
998 CONFIG_CMD_IDE * IDE harddisk support
999 CONFIG_CMD_IMI iminfo
1000 CONFIG_CMD_IMLS List all images found in NOR flash
1001 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1002 CONFIG_CMD_IMMAP * IMMR dump support
1003 CONFIG_CMD_IMPORTENV * import an environment
1004 CONFIG_CMD_INI * import data from an ini file into the env
1005 CONFIG_CMD_IRQ * irqinfo
1006 CONFIG_CMD_ITEST Integer/string test of 2 values
1007 CONFIG_CMD_JFFS2 * JFFS2 Support
1008 CONFIG_CMD_KGDB * kgdb
1009 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1010 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1012 CONFIG_CMD_LOADB loadb
1013 CONFIG_CMD_LOADS loads
1014 CONFIG_CMD_MD5SUM * print md5 message digest
1015 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1016 CONFIG_CMD_MEMINFO * Display detailed memory information
1017 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1019 CONFIG_CMD_MEMTEST * mtest
1020 CONFIG_CMD_MISC Misc functions like sleep etc
1021 CONFIG_CMD_MMC * MMC memory mapped support
1022 CONFIG_CMD_MII * MII utility commands
1023 CONFIG_CMD_MTDPARTS * MTD partition support
1024 CONFIG_CMD_NAND * NAND support
1025 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1026 CONFIG_CMD_NFS NFS support
1027 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1028 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1029 CONFIG_CMD_PCI * pciinfo
1030 CONFIG_CMD_PCMCIA * PCMCIA support
1031 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1033 CONFIG_CMD_PORTIO * Port I/O
1034 CONFIG_CMD_READ * Read raw data from partition
1035 CONFIG_CMD_REGINFO * Register dump
1036 CONFIG_CMD_RUN run command in env variable
1037 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1038 CONFIG_CMD_SAVES * save S record dump
1039 CONFIG_CMD_SCSI * SCSI Support
1040 CONFIG_CMD_SDRAM * print SDRAM configuration information
1041 (requires CONFIG_CMD_I2C)
1042 CONFIG_CMD_SETGETDCR Support for DCR Register access
1044 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1045 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1046 (requires CONFIG_CMD_MEMORY)
1047 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1048 CONFIG_CMD_SOURCE "source" command Support
1049 CONFIG_CMD_SPI * SPI serial bus support
1050 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1051 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1052 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1053 CONFIG_CMD_TIMER * access to the system tick timer
1054 CONFIG_CMD_USB * USB support
1055 CONFIG_CMD_CDP * Cisco Discover Protocol support
1056 CONFIG_CMD_MFSL * Microblaze FSL support
1057 CONFIG_CMD_XIMG Load part of Multi Image
1058 CONFIG_CMD_UUID * Generate random UUID or GUID string
1060 EXAMPLE: If you want all functions except of network
1061 support you can write:
1063 #include "config_cmd_all.h"
1064 #undef CONFIG_CMD_NET
1067 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1069 Note: Don't enable the "icache" and "dcache" commands
1070 (configuration option CONFIG_CMD_CACHE) unless you know
1071 what you (and your U-Boot users) are doing. Data
1072 cache cannot be enabled on systems like the 8xx or
1073 8260 (where accesses to the IMMR region must be
1074 uncached), and it cannot be disabled on all other
1075 systems where we (mis-) use the data cache to hold an
1076 initial stack and some data.
1079 XXX - this list needs to get updated!
1081 - Regular expression support:
1083 If this variable is defined, U-Boot is linked against
1084 the SLRE (Super Light Regular Expression) library,
1085 which adds regex support to some commands, as for
1086 example "env grep" and "setexpr".
1090 If this variable is defined, U-Boot will use a device tree
1091 to configure its devices, instead of relying on statically
1092 compiled #defines in the board file. This option is
1093 experimental and only available on a few boards. The device
1094 tree is available in the global data as gd->fdt_blob.
1096 U-Boot needs to get its device tree from somewhere. This can
1097 be done using one of the two options below:
1100 If this variable is defined, U-Boot will embed a device tree
1101 binary in its image. This device tree file should be in the
1102 board directory and called <soc>-<board>.dts. The binary file
1103 is then picked up in board_init_f() and made available through
1104 the global data structure as gd->blob.
1107 If this variable is defined, U-Boot will build a device tree
1108 binary. It will be called u-boot.dtb. Architecture-specific
1109 code will locate it at run-time. Generally this works by:
1111 cat u-boot.bin u-boot.dtb >image.bin
1113 and in fact, U-Boot does this for you, creating a file called
1114 u-boot-dtb.bin which is useful in the common case. You can
1115 still use the individual files if you need something more
1120 If this variable is defined, it enables watchdog
1121 support for the SoC. There must be support in the SoC
1122 specific code for a watchdog. For the 8xx and 8260
1123 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1124 register. When supported for a specific SoC is
1125 available, then no further board specific code should
1126 be needed to use it.
1129 When using a watchdog circuitry external to the used
1130 SoC, then define this variable and provide board
1131 specific code for the "hw_watchdog_reset" function.
1134 CONFIG_VERSION_VARIABLE
1135 If this variable is defined, an environment variable
1136 named "ver" is created by U-Boot showing the U-Boot
1137 version as printed by the "version" command.
1138 Any change to this variable will be reverted at the
1143 When CONFIG_CMD_DATE is selected, the type of the RTC
1144 has to be selected, too. Define exactly one of the
1147 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1148 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1149 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1150 CONFIG_RTC_MC146818 - use MC146818 RTC
1151 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1152 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1153 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1154 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1155 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1156 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1157 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1158 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1161 Note that if the RTC uses I2C, then the I2C interface
1162 must also be configured. See I2C Support, below.
1165 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1167 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1168 chip-ngpio pairs that tell the PCA953X driver the number of
1169 pins supported by a particular chip.
1171 Note that if the GPIO device uses I2C, then the I2C interface
1172 must also be configured. See I2C Support, below.
1174 - Timestamp Support:
1176 When CONFIG_TIMESTAMP is selected, the timestamp
1177 (date and time) of an image is printed by image
1178 commands like bootm or iminfo. This option is
1179 automatically enabled when you select CONFIG_CMD_DATE .
1181 - Partition Labels (disklabels) Supported:
1182 Zero or more of the following:
1183 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1184 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1185 Intel architecture, USB sticks, etc.
1186 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1187 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1188 bootloader. Note 2TB partition limit; see
1190 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1192 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1193 CONFIG_CMD_SCSI) you must configure support for at
1194 least one non-MTD partition type as well.
1197 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1198 board configurations files but used nowhere!
1200 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1201 be performed by calling the function
1202 ide_set_reset(int reset)
1203 which has to be defined in a board specific file
1208 Set this to enable ATAPI support.
1213 Set this to enable support for disks larger than 137GB
1214 Also look at CONFIG_SYS_64BIT_LBA.
1215 Whithout these , LBA48 support uses 32bit variables and will 'only'
1216 support disks up to 2.1TB.
1218 CONFIG_SYS_64BIT_LBA:
1219 When enabled, makes the IDE subsystem use 64bit sector addresses.
1223 At the moment only there is only support for the
1224 SYM53C8XX SCSI controller; define
1225 CONFIG_SCSI_SYM53C8XX to enable it.
1227 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1228 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1229 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1230 maximum numbers of LUNs, SCSI ID's and target
1232 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1234 The environment variable 'scsidevs' is set to the number of
1235 SCSI devices found during the last scan.
1237 - NETWORK Support (PCI):
1239 Support for Intel 8254x/8257x gigabit chips.
1242 Utility code for direct access to the SPI bus on Intel 8257x.
1243 This does not do anything useful unless you set at least one
1244 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1246 CONFIG_E1000_SPI_GENERIC
1247 Allow generic access to the SPI bus on the Intel 8257x, for
1248 example with the "sspi" command.
1251 Management command for E1000 devices. When used on devices
1252 with SPI support you can reprogram the EEPROM from U-Boot.
1254 CONFIG_E1000_FALLBACK_MAC
1255 default MAC for empty EEPROM after production.
1258 Support for Intel 82557/82559/82559ER chips.
1259 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1260 write routine for first time initialisation.
1263 Support for Digital 2114x chips.
1264 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1265 modem chip initialisation (KS8761/QS6611).
1268 Support for National dp83815 chips.
1271 Support for National dp8382[01] gigabit chips.
1273 - NETWORK Support (other):
1275 CONFIG_DRIVER_AT91EMAC
1276 Support for AT91RM9200 EMAC.
1279 Define this to use reduced MII inteface
1281 CONFIG_DRIVER_AT91EMAC_QUIET
1282 If this defined, the driver is quiet.
1283 The driver doen't show link status messages.
1285 CONFIG_CALXEDA_XGMAC
1286 Support for the Calxeda XGMAC device
1289 Support for SMSC's LAN91C96 chips.
1291 CONFIG_LAN91C96_BASE
1292 Define this to hold the physical address
1293 of the LAN91C96's I/O space
1295 CONFIG_LAN91C96_USE_32_BIT
1296 Define this to enable 32 bit addressing
1299 Support for SMSC's LAN91C111 chip
1301 CONFIG_SMC91111_BASE
1302 Define this to hold the physical address
1303 of the device (I/O space)
1305 CONFIG_SMC_USE_32_BIT
1306 Define this if data bus is 32 bits
1308 CONFIG_SMC_USE_IOFUNCS
1309 Define this to use i/o functions instead of macros
1310 (some hardware wont work with macros)
1312 CONFIG_DRIVER_TI_EMAC
1313 Support for davinci emac
1315 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1316 Define this if you have more then 3 PHYs.
1319 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1321 CONFIG_FTGMAC100_EGIGA
1322 Define this to use GE link update with gigabit PHY.
1323 Define this if FTGMAC100 is connected to gigabit PHY.
1324 If your system has 10/100 PHY only, it might not occur
1325 wrong behavior. Because PHY usually return timeout or
1326 useless data when polling gigabit status and gigabit
1327 control registers. This behavior won't affect the
1328 correctnessof 10/100 link speed update.
1331 Support for SMSC's LAN911x and LAN921x chips
1334 Define this to hold the physical address
1335 of the device (I/O space)
1337 CONFIG_SMC911X_32_BIT
1338 Define this if data bus is 32 bits
1340 CONFIG_SMC911X_16_BIT
1341 Define this if data bus is 16 bits. If your processor
1342 automatically converts one 32 bit word to two 16 bit
1343 words you may also try CONFIG_SMC911X_32_BIT.
1346 Support for Renesas on-chip Ethernet controller
1348 CONFIG_SH_ETHER_USE_PORT
1349 Define the number of ports to be used
1351 CONFIG_SH_ETHER_PHY_ADDR
1352 Define the ETH PHY's address
1354 CONFIG_SH_ETHER_CACHE_WRITEBACK
1355 If this option is set, the driver enables cache flush.
1359 Support TPM devices.
1362 Support for i2c bus TPM devices. Only one device
1363 per system is supported at this time.
1365 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1366 Define the the i2c bus number for the TPM device
1368 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1369 Define the TPM's address on the i2c bus
1371 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1372 Define the burst count bytes upper limit
1374 CONFIG_TPM_ATMEL_TWI
1375 Support for Atmel TWI TPM device. Requires I2C support.
1378 Support for generic parallel port TPM devices. Only one device
1379 per system is supported at this time.
1381 CONFIG_TPM_TIS_BASE_ADDRESS
1382 Base address where the generic TPM device is mapped
1383 to. Contemporary x86 systems usually map it at
1387 Add tpm monitor functions.
1388 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1389 provides monitor access to authorized functions.
1392 Define this to enable the TPM support library which provides
1393 functional interfaces to some TPM commands.
1394 Requires support for a TPM device.
1396 CONFIG_TPM_AUTH_SESSIONS
1397 Define this to enable authorized functions in the TPM library.
1398 Requires CONFIG_TPM and CONFIG_SHA1.
1401 At the moment only the UHCI host controller is
1402 supported (PIP405, MIP405, MPC5200); define
1403 CONFIG_USB_UHCI to enable it.
1404 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1405 and define CONFIG_USB_STORAGE to enable the USB
1408 Supported are USB Keyboards and USB Floppy drives
1410 MPC5200 USB requires additional defines:
1412 for 528 MHz Clock: 0x0001bbbb
1416 for differential drivers: 0x00001000
1417 for single ended drivers: 0x00005000
1418 for differential drivers on PSC3: 0x00000100
1419 for single ended drivers on PSC3: 0x00004100
1420 CONFIG_SYS_USB_EVENT_POLL
1421 May be defined to allow interrupt polling
1422 instead of using asynchronous interrupts
1424 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1425 txfilltuning field in the EHCI controller on reset.
1427 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1428 interval for usb hub power-on delay.(minimum 100msec)
1431 Define the below if you wish to use the USB console.
1432 Once firmware is rebuilt from a serial console issue the
1433 command "setenv stdin usbtty; setenv stdout usbtty" and
1434 attach your USB cable. The Unix command "dmesg" should print
1435 it has found a new device. The environment variable usbtty
1436 can be set to gserial or cdc_acm to enable your device to
1437 appear to a USB host as a Linux gserial device or a
1438 Common Device Class Abstract Control Model serial device.
1439 If you select usbtty = gserial you should be able to enumerate
1441 # modprobe usbserial vendor=0xVendorID product=0xProductID
1442 else if using cdc_acm, simply setting the environment
1443 variable usbtty to be cdc_acm should suffice. The following
1444 might be defined in YourBoardName.h
1447 Define this to build a UDC device
1450 Define this to have a tty type of device available to
1451 talk to the UDC device
1454 Define this to enable the high speed support for usb
1455 device and usbtty. If this feature is enabled, a routine
1456 int is_usbd_high_speed(void)
1457 also needs to be defined by the driver to dynamically poll
1458 whether the enumeration has succeded at high speed or full
1461 CONFIG_SYS_CONSOLE_IS_IN_ENV
1462 Define this if you want stdin, stdout &/or stderr to
1466 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1467 Derive USB clock from external clock "blah"
1468 - CONFIG_SYS_USB_EXTC_CLK 0x02
1470 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1471 Derive USB clock from brgclk
1472 - CONFIG_SYS_USB_BRG_CLK 0x04
1474 If you have a USB-IF assigned VendorID then you may wish to
1475 define your own vendor specific values either in BoardName.h
1476 or directly in usbd_vendor_info.h. If you don't define
1477 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1478 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1479 should pretend to be a Linux device to it's target host.
1481 CONFIG_USBD_MANUFACTURER
1482 Define this string as the name of your company for
1483 - CONFIG_USBD_MANUFACTURER "my company"
1485 CONFIG_USBD_PRODUCT_NAME
1486 Define this string as the name of your product
1487 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1489 CONFIG_USBD_VENDORID
1490 Define this as your assigned Vendor ID from the USB
1491 Implementors Forum. This *must* be a genuine Vendor ID
1492 to avoid polluting the USB namespace.
1493 - CONFIG_USBD_VENDORID 0xFFFF
1495 CONFIG_USBD_PRODUCTID
1496 Define this as the unique Product ID
1498 - CONFIG_USBD_PRODUCTID 0xFFFF
1500 - ULPI Layer Support:
1501 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1502 the generic ULPI layer. The generic layer accesses the ULPI PHY
1503 via the platform viewport, so you need both the genric layer and
1504 the viewport enabled. Currently only Chipidea/ARC based
1505 viewport is supported.
1506 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1507 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1508 If your ULPI phy needs a different reference clock than the
1509 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1510 the appropriate value in Hz.
1513 The MMC controller on the Intel PXA is supported. To
1514 enable this define CONFIG_MMC. The MMC can be
1515 accessed from the boot prompt by mapping the device
1516 to physical memory similar to flash. Command line is
1517 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1518 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1521 Support for Renesas on-chip MMCIF controller
1523 CONFIG_SH_MMCIF_ADDR
1524 Define the base address of MMCIF registers
1527 Define the clock frequency for MMCIF
1530 Enable the generic MMC driver
1532 CONFIG_SUPPORT_EMMC_BOOT
1533 Enable some additional features of the eMMC boot partitions.
1535 CONFIG_SUPPORT_EMMC_RPMB
1536 Enable the commands for reading, writing and programming the
1537 key for the Replay Protection Memory Block partition in eMMC.
1539 - USB Device Firmware Update (DFU) class support:
1541 This enables the USB portion of the DFU USB class
1544 This enables the command "dfu" which is used to have
1545 U-Boot create a DFU class device via USB. This command
1546 requires that the "dfu_alt_info" environment variable be
1547 set and define the alt settings to expose to the host.
1550 This enables support for exposing (e)MMC devices via DFU.
1553 This enables support for exposing NAND devices via DFU.
1556 This enables support for exposing RAM via DFU.
1557 Note: DFU spec refer to non-volatile memory usage, but
1558 allow usages beyond the scope of spec - here RAM usage,
1559 one that would help mostly the developer.
1561 CONFIG_SYS_DFU_DATA_BUF_SIZE
1562 Dfu transfer uses a buffer before writing data to the
1563 raw storage device. Make the size (in bytes) of this buffer
1564 configurable. The size of this buffer is also configurable
1565 through the "dfu_bufsiz" environment variable.
1567 CONFIG_SYS_DFU_MAX_FILE_SIZE
1568 When updating files rather than the raw storage device,
1569 we use a static buffer to copy the file into and then write
1570 the buffer once we've been given the whole file. Define
1571 this to the maximum filesize (in bytes) for the buffer.
1572 Default is 4 MiB if undefined.
1574 DFU_DEFAULT_POLL_TIMEOUT
1575 Poll timeout [ms], is the timeout a device can send to the
1576 host. The host must wait for this timeout before sending
1577 a subsequent DFU_GET_STATUS request to the device.
1579 DFU_MANIFEST_POLL_TIMEOUT
1580 Poll timeout [ms], which the device sends to the host when
1581 entering dfuMANIFEST state. Host waits this timeout, before
1582 sending again an USB request to the device.
1584 - USB Device Android Fastboot support:
1586 This enables the command "fastboot" which enables the Android
1587 fastboot mode for the platform's USB device. Fastboot is a USB
1588 protocol for downloading images, flashing and device control
1589 used on Android devices.
1590 See doc/README.android-fastboot for more information.
1592 CONFIG_ANDROID_BOOT_IMAGE
1593 This enables support for booting images which use the Android
1594 image format header.
1596 CONFIG_USB_FASTBOOT_BUF_ADDR
1597 The fastboot protocol requires a large memory buffer for
1598 downloads. Define this to the starting RAM address to use for
1601 CONFIG_USB_FASTBOOT_BUF_SIZE
1602 The fastboot protocol requires a large memory buffer for
1603 downloads. This buffer should be as large as possible for a
1604 platform. Define this to the size available RAM for fastboot.
1606 - Journaling Flash filesystem support:
1607 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1608 CONFIG_JFFS2_NAND_DEV
1609 Define these for a default partition on a NAND device
1611 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1612 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1613 Define these for a default partition on a NOR device
1615 CONFIG_SYS_JFFS_CUSTOM_PART
1616 Define this to create an own partition. You have to provide a
1617 function struct part_info* jffs2_part_info(int part_num)
1619 If you define only one JFFS2 partition you may also want to
1620 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1621 to disable the command chpart. This is the default when you
1622 have not defined a custom partition
1624 - FAT(File Allocation Table) filesystem write function support:
1627 Define this to enable support for saving memory data as a
1628 file in FAT formatted partition.
1630 This will also enable the command "fatwrite" enabling the
1631 user to write files to FAT.
1633 CBFS (Coreboot Filesystem) support
1636 Define this to enable support for reading from a Coreboot
1637 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1640 - FAT(File Allocation Table) filesystem cluster size:
1641 CONFIG_FS_FAT_MAX_CLUSTSIZE
1643 Define the max cluster size for fat operations else
1644 a default value of 65536 will be defined.
1649 Define this to enable standard (PC-Style) keyboard
1653 Standard PC keyboard driver with US (is default) and
1654 GERMAN key layout (switch via environment 'keymap=de') support.
1655 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1656 for cfb_console. Supports cursor blinking.
1659 Enables a Chrome OS keyboard using the CROS_EC interface.
1660 This uses CROS_EC to communicate with a second microcontroller
1661 which provides key scans on request.
1666 Define this to enable video support (for output to
1669 CONFIG_VIDEO_CT69000
1671 Enable Chips & Technologies 69000 Video chip
1673 CONFIG_VIDEO_SMI_LYNXEM
1674 Enable Silicon Motion SMI 712/710/810 Video chip. The
1675 video output is selected via environment 'videoout'
1676 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1679 For the CT69000 and SMI_LYNXEM drivers, videomode is
1680 selected via environment 'videomode'. Two different ways
1682 - "videomode=num" 'num' is a standard LiLo mode numbers.
1683 Following standard modes are supported (* is default):
1685 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1686 -------------+---------------------------------------------
1687 8 bits | 0x301* 0x303 0x305 0x161 0x307
1688 15 bits | 0x310 0x313 0x316 0x162 0x319
1689 16 bits | 0x311 0x314 0x317 0x163 0x31A
1690 24 bits | 0x312 0x315 0x318 ? 0x31B
1691 -------------+---------------------------------------------
1692 (i.e. setenv videomode 317; saveenv; reset;)
1694 - "videomode=bootargs" all the video parameters are parsed
1695 from the bootargs. (See drivers/video/videomodes.c)
1698 CONFIG_VIDEO_SED13806
1699 Enable Epson SED13806 driver. This driver supports 8bpp
1700 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1701 or CONFIG_VIDEO_SED13806_16BPP
1704 Enable the Freescale DIU video driver. Reference boards for
1705 SOCs that have a DIU should define this macro to enable DIU
1706 support, and should also define these other macros:
1712 CONFIG_VIDEO_SW_CURSOR
1713 CONFIG_VGA_AS_SINGLE_DEVICE
1715 CONFIG_VIDEO_BMP_LOGO
1717 The DIU driver will look for the 'video-mode' environment
1718 variable, and if defined, enable the DIU as a console during
1719 boot. See the documentation file README.video for a
1720 description of this variable.
1724 Enable the VGA video / BIOS for x86. The alternative if you
1725 are using coreboot is to use the coreboot frame buffer
1732 Define this to enable a custom keyboard support.
1733 This simply calls drv_keyboard_init() which must be
1734 defined in your board-specific files.
1735 The only board using this so far is RBC823.
1737 - LCD Support: CONFIG_LCD
1739 Define this to enable LCD support (for output to LCD
1740 display); also select one of the supported displays
1741 by defining one of these:
1745 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1747 CONFIG_NEC_NL6448AC33:
1749 NEC NL6448AC33-18. Active, color, single scan.
1751 CONFIG_NEC_NL6448BC20
1753 NEC NL6448BC20-08. 6.5", 640x480.
1754 Active, color, single scan.
1756 CONFIG_NEC_NL6448BC33_54
1758 NEC NL6448BC33-54. 10.4", 640x480.
1759 Active, color, single scan.
1763 Sharp 320x240. Active, color, single scan.
1764 It isn't 16x9, and I am not sure what it is.
1766 CONFIG_SHARP_LQ64D341
1768 Sharp LQ64D341 display, 640x480.
1769 Active, color, single scan.
1773 HLD1045 display, 640x480.
1774 Active, color, single scan.
1778 Optrex CBL50840-2 NF-FW 99 22 M5
1780 Hitachi LMG6912RPFC-00T
1784 320x240. Black & white.
1786 Normally display is black on white background; define
1787 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1789 CONFIG_LCD_ALIGNMENT
1791 Normally the LCD is page-aligned (tyically 4KB). If this is
1792 defined then the LCD will be aligned to this value instead.
1793 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1794 here, since it is cheaper to change data cache settings on
1795 a per-section basis.
1797 CONFIG_CONSOLE_SCROLL_LINES
1799 When the console need to be scrolled, this is the number of
1800 lines to scroll by. It defaults to 1. Increasing this makes
1801 the console jump but can help speed up operation when scrolling
1806 Support drawing of RLE8-compressed bitmaps on the LCD.
1810 Enables an 'i2c edid' command which can read EDID
1811 information over I2C from an attached LCD display.
1813 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1815 If this option is set, the environment is checked for
1816 a variable "splashimage". If found, the usual display
1817 of logo, copyright and system information on the LCD
1818 is suppressed and the BMP image at the address
1819 specified in "splashimage" is loaded instead. The
1820 console is redirected to the "nulldev", too. This
1821 allows for a "silent" boot where a splash screen is
1822 loaded very quickly after power-on.
1824 CONFIG_SPLASHIMAGE_GUARD
1826 If this option is set, then U-Boot will prevent the environment
1827 variable "splashimage" from being set to a problematic address
1828 (see README.displaying-bmps).
1829 This option is useful for targets where, due to alignment
1830 restrictions, an improperly aligned BMP image will cause a data
1831 abort. If you think you will not have problems with unaligned
1832 accesses (for example because your toolchain prevents them)
1833 there is no need to set this option.
1835 CONFIG_SPLASH_SCREEN_ALIGN
1837 If this option is set the splash image can be freely positioned
1838 on the screen. Environment variable "splashpos" specifies the
1839 position as "x,y". If a positive number is given it is used as
1840 number of pixel from left/top. If a negative number is given it
1841 is used as number of pixel from right/bottom. You can also
1842 specify 'm' for centering the image.
1845 setenv splashpos m,m
1846 => image at center of screen
1848 setenv splashpos 30,20
1849 => image at x = 30 and y = 20
1851 setenv splashpos -10,m
1852 => vertically centered image
1853 at x = dspWidth - bmpWidth - 9
1855 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1857 If this option is set, additionally to standard BMP
1858 images, gzipped BMP images can be displayed via the
1859 splashscreen support or the bmp command.
1861 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1863 If this option is set, 8-bit RLE compressed BMP images
1864 can be displayed via the splashscreen support or the
1867 - Do compresssing for memory range:
1870 If this option is set, it would use zlib deflate method
1871 to compress the specified memory at its best effort.
1873 - Compression support:
1876 Enabled by default to support gzip compressed images.
1880 If this option is set, support for bzip2 compressed
1881 images is included. If not, only uncompressed and gzip
1882 compressed images are supported.
1884 NOTE: the bzip2 algorithm requires a lot of RAM, so
1885 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1890 If this option is set, support for lzma compressed
1893 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1894 requires an amount of dynamic memory that is given by the
1897 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1899 Where lc and lp stand for, respectively, Literal context bits
1900 and Literal pos bits.
1902 This value is upper-bounded by 14MB in the worst case. Anyway,
1903 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1904 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1905 a very small buffer.
1907 Use the lzmainfo tool to determinate the lc and lp values and
1908 then calculate the amount of needed dynamic memory (ensuring
1909 the appropriate CONFIG_SYS_MALLOC_LEN value).
1913 If this option is set, support for LZO compressed images
1919 The address of PHY on MII bus.
1921 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1923 The clock frequency of the MII bus
1927 If this option is set, support for speed/duplex
1928 detection of gigabit PHY is included.
1930 CONFIG_PHY_RESET_DELAY
1932 Some PHY like Intel LXT971A need extra delay after
1933 reset before any MII register access is possible.
1934 For such PHY, set this option to the usec delay
1935 required. (minimum 300usec for LXT971A)
1937 CONFIG_PHY_CMD_DELAY (ppc4xx)
1939 Some PHY like Intel LXT971A need extra delay after
1940 command issued before MII status register can be read
1950 Define a default value for Ethernet address to use
1951 for the respective Ethernet interface, in case this
1952 is not determined automatically.
1957 Define a default value for the IP address to use for
1958 the default Ethernet interface, in case this is not
1959 determined through e.g. bootp.
1960 (Environment variable "ipaddr")
1962 - Server IP address:
1965 Defines a default value for the IP address of a TFTP
1966 server to contact when using the "tftboot" command.
1967 (Environment variable "serverip")
1969 CONFIG_KEEP_SERVERADDR
1971 Keeps the server's MAC address, in the env 'serveraddr'
1972 for passing to bootargs (like Linux's netconsole option)
1974 - Gateway IP address:
1977 Defines a default value for the IP address of the
1978 default router where packets to other networks are
1980 (Environment variable "gatewayip")
1985 Defines a default value for the subnet mask (or
1986 routing prefix) which is used to determine if an IP
1987 address belongs to the local subnet or needs to be
1988 forwarded through a router.
1989 (Environment variable "netmask")
1991 - Multicast TFTP Mode:
1994 Defines whether you want to support multicast TFTP as per
1995 rfc-2090; for example to work with atftp. Lets lots of targets
1996 tftp down the same boot image concurrently. Note: the Ethernet
1997 driver in use must provide a function: mcast() to join/leave a
2000 - BOOTP Recovery Mode:
2001 CONFIG_BOOTP_RANDOM_DELAY
2003 If you have many targets in a network that try to
2004 boot using BOOTP, you may want to avoid that all
2005 systems send out BOOTP requests at precisely the same
2006 moment (which would happen for instance at recovery
2007 from a power failure, when all systems will try to
2008 boot, thus flooding the BOOTP server. Defining
2009 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2010 inserted before sending out BOOTP requests. The
2011 following delays are inserted then:
2013 1st BOOTP request: delay 0 ... 1 sec
2014 2nd BOOTP request: delay 0 ... 2 sec
2015 3rd BOOTP request: delay 0 ... 4 sec
2017 BOOTP requests: delay 0 ... 8 sec
2019 - DHCP Advanced Options:
2020 You can fine tune the DHCP functionality by defining
2021 CONFIG_BOOTP_* symbols:
2023 CONFIG_BOOTP_SUBNETMASK
2024 CONFIG_BOOTP_GATEWAY
2025 CONFIG_BOOTP_HOSTNAME
2026 CONFIG_BOOTP_NISDOMAIN
2027 CONFIG_BOOTP_BOOTPATH
2028 CONFIG_BOOTP_BOOTFILESIZE
2031 CONFIG_BOOTP_SEND_HOSTNAME
2032 CONFIG_BOOTP_NTPSERVER
2033 CONFIG_BOOTP_TIMEOFFSET
2034 CONFIG_BOOTP_VENDOREX
2035 CONFIG_BOOTP_MAY_FAIL
2037 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2038 environment variable, not the BOOTP server.
2040 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2041 after the configured retry count, the call will fail
2042 instead of starting over. This can be used to fail over
2043 to Link-local IP address configuration if the DHCP server
2046 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2047 serverip from a DHCP server, it is possible that more
2048 than one DNS serverip is offered to the client.
2049 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2050 serverip will be stored in the additional environment
2051 variable "dnsip2". The first DNS serverip is always
2052 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2055 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2056 to do a dynamic update of a DNS server. To do this, they
2057 need the hostname of the DHCP requester.
2058 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2059 of the "hostname" environment variable is passed as
2060 option 12 to the DHCP server.
2062 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2064 A 32bit value in microseconds for a delay between
2065 receiving a "DHCP Offer" and sending the "DHCP Request".
2066 This fixes a problem with certain DHCP servers that don't
2067 respond 100% of the time to a "DHCP request". E.g. On an
2068 AT91RM9200 processor running at 180MHz, this delay needed
2069 to be *at least* 15,000 usec before a Windows Server 2003
2070 DHCP server would reply 100% of the time. I recommend at
2071 least 50,000 usec to be safe. The alternative is to hope
2072 that one of the retries will be successful but note that
2073 the DHCP timeout and retry process takes a longer than
2076 - Link-local IP address negotiation:
2077 Negotiate with other link-local clients on the local network
2078 for an address that doesn't require explicit configuration.
2079 This is especially useful if a DHCP server cannot be guaranteed
2080 to exist in all environments that the device must operate.
2082 See doc/README.link-local for more information.
2085 CONFIG_CDP_DEVICE_ID
2087 The device id used in CDP trigger frames.
2089 CONFIG_CDP_DEVICE_ID_PREFIX
2091 A two character string which is prefixed to the MAC address
2096 A printf format string which contains the ascii name of
2097 the port. Normally is set to "eth%d" which sets
2098 eth0 for the first Ethernet, eth1 for the second etc.
2100 CONFIG_CDP_CAPABILITIES
2102 A 32bit integer which indicates the device capabilities;
2103 0x00000010 for a normal host which does not forwards.
2107 An ascii string containing the version of the software.
2111 An ascii string containing the name of the platform.
2115 A 32bit integer sent on the trigger.
2117 CONFIG_CDP_POWER_CONSUMPTION
2119 A 16bit integer containing the power consumption of the
2120 device in .1 of milliwatts.
2122 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2124 A byte containing the id of the VLAN.
2126 - Status LED: CONFIG_STATUS_LED
2128 Several configurations allow to display the current
2129 status using a LED. For instance, the LED will blink
2130 fast while running U-Boot code, stop blinking as
2131 soon as a reply to a BOOTP request was received, and
2132 start blinking slow once the Linux kernel is running
2133 (supported by a status LED driver in the Linux
2134 kernel). Defining CONFIG_STATUS_LED enables this
2140 The status LED can be connected to a GPIO pin.
2141 In such cases, the gpio_led driver can be used as a
2142 status LED backend implementation. Define CONFIG_GPIO_LED
2143 to include the gpio_led driver in the U-Boot binary.
2145 CONFIG_GPIO_LED_INVERTED_TABLE
2146 Some GPIO connected LEDs may have inverted polarity in which
2147 case the GPIO high value corresponds to LED off state and
2148 GPIO low value corresponds to LED on state.
2149 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2150 with a list of GPIO LEDs that have inverted polarity.
2152 - CAN Support: CONFIG_CAN_DRIVER
2154 Defining CONFIG_CAN_DRIVER enables CAN driver support
2155 on those systems that support this (optional)
2156 feature, like the TQM8xxL modules.
2158 - I2C Support: CONFIG_SYS_I2C
2160 This enable the NEW i2c subsystem, and will allow you to use
2161 i2c commands at the u-boot command line (as long as you set
2162 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2163 based realtime clock chips or other i2c devices. See
2164 common/cmd_i2c.c for a description of the command line
2167 ported i2c driver to the new framework:
2168 - drivers/i2c/soft_i2c.c:
2169 - activate first bus with CONFIG_SYS_I2C_SOFT define
2170 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2171 for defining speed and slave address
2172 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2173 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2174 for defining speed and slave address
2175 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2176 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2177 for defining speed and slave address
2178 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2179 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2180 for defining speed and slave address
2182 - drivers/i2c/fsl_i2c.c:
2183 - activate i2c driver with CONFIG_SYS_I2C_FSL
2184 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2185 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2186 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2188 - If your board supports a second fsl i2c bus, define
2189 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2190 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2191 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2194 - drivers/i2c/tegra_i2c.c:
2195 - activate this driver with CONFIG_SYS_I2C_TEGRA
2196 - This driver adds 4 i2c buses with a fix speed from
2197 100000 and the slave addr 0!
2199 - drivers/i2c/ppc4xx_i2c.c
2200 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2201 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2202 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2204 - drivers/i2c/i2c_mxc.c
2205 - activate this driver with CONFIG_SYS_I2C_MXC
2206 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2207 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2208 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2209 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2210 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2211 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2212 If thoses defines are not set, default value is 100000
2213 for speed, and 0 for slave.
2215 - drivers/i2c/rcar_i2c.c:
2216 - activate this driver with CONFIG_SYS_I2C_RCAR
2217 - This driver adds 4 i2c buses
2219 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2220 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2221 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2222 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2223 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2224 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2225 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2226 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2227 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2229 - drivers/i2c/sh_i2c.c:
2230 - activate this driver with CONFIG_SYS_I2C_SH
2231 - This driver adds from 2 to 5 i2c buses
2233 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2234 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2235 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2236 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2237 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2238 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2239 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2240 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2241 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2242 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2243 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2244 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2245 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2247 - drivers/i2c/omap24xx_i2c.c
2248 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2249 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2250 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2251 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2252 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2253 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2254 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2255 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2256 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2257 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2258 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2260 - drivers/i2c/zynq_i2c.c
2261 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2262 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2263 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2265 - drivers/i2c/s3c24x0_i2c.c:
2266 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2267 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2268 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2269 with a fix speed from 100000 and the slave addr 0!
2273 CONFIG_SYS_NUM_I2C_BUSES
2274 Hold the number of i2c busses you want to use. If you
2275 don't use/have i2c muxes on your i2c bus, this
2276 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2279 CONFIG_SYS_I2C_DIRECT_BUS
2280 define this, if you don't use i2c muxes on your hardware.
2281 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2284 CONFIG_SYS_I2C_MAX_HOPS
2285 define how many muxes are maximal consecutively connected
2286 on one i2c bus. If you not use i2c muxes, omit this
2289 CONFIG_SYS_I2C_BUSES
2290 hold a list of busses you want to use, only used if
2291 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2292 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2293 CONFIG_SYS_NUM_I2C_BUSES = 9:
2295 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2296 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2297 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2298 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2299 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2300 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2301 {1, {I2C_NULL_HOP}}, \
2302 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2303 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2307 bus 0 on adapter 0 without a mux
2308 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2309 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2310 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2311 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2312 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2313 bus 6 on adapter 1 without a mux
2314 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2315 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2317 If you do not have i2c muxes on your board, omit this define.
2319 - Legacy I2C Support: CONFIG_HARD_I2C
2321 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2322 provides the following compelling advantages:
2324 - more than one i2c adapter is usable
2325 - approved multibus support
2326 - better i2c mux support
2328 ** Please consider updating your I2C driver now. **
2330 These enable legacy I2C serial bus commands. Defining
2331 CONFIG_HARD_I2C will include the appropriate I2C driver
2332 for the selected CPU.
2334 This will allow you to use i2c commands at the u-boot
2335 command line (as long as you set CONFIG_CMD_I2C in
2336 CONFIG_COMMANDS) and communicate with i2c based realtime
2337 clock chips. See common/cmd_i2c.c for a description of the
2338 command line interface.
2340 CONFIG_HARD_I2C selects a hardware I2C controller.
2342 There are several other quantities that must also be
2343 defined when you define CONFIG_HARD_I2C.
2345 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2346 to be the frequency (in Hz) at which you wish your i2c bus
2347 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2348 the CPU's i2c node address).
2350 Now, the u-boot i2c code for the mpc8xx
2351 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2352 and so its address should therefore be cleared to 0 (See,
2353 eg, MPC823e User's Manual p.16-473). So, set
2354 CONFIG_SYS_I2C_SLAVE to 0.
2356 CONFIG_SYS_I2C_INIT_MPC5XXX
2358 When a board is reset during an i2c bus transfer
2359 chips might think that the current transfer is still
2360 in progress. Reset the slave devices by sending start
2361 commands until the slave device responds.
2363 That's all that's required for CONFIG_HARD_I2C.
2365 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2366 then the following macros need to be defined (examples are
2367 from include/configs/lwmon.h):
2371 (Optional). Any commands necessary to enable the I2C
2372 controller or configure ports.
2374 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2378 (Only for MPC8260 CPU). The I/O port to use (the code
2379 assumes both bits are on the same port). Valid values
2380 are 0..3 for ports A..D.
2384 The code necessary to make the I2C data line active
2385 (driven). If the data line is open collector, this
2388 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2392 The code necessary to make the I2C data line tri-stated
2393 (inactive). If the data line is open collector, this
2396 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2400 Code that returns true if the I2C data line is high,
2403 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2407 If <bit> is true, sets the I2C data line high. If it
2408 is false, it clears it (low).
2410 eg: #define I2C_SDA(bit) \
2411 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2412 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2416 If <bit> is true, sets the I2C clock line high. If it
2417 is false, it clears it (low).
2419 eg: #define I2C_SCL(bit) \
2420 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2421 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2425 This delay is invoked four times per clock cycle so this
2426 controls the rate of data transfer. The data rate thus
2427 is 1 / (I2C_DELAY * 4). Often defined to be something
2430 #define I2C_DELAY udelay(2)
2432 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2434 If your arch supports the generic GPIO framework (asm/gpio.h),
2435 then you may alternatively define the two GPIOs that are to be
2436 used as SCL / SDA. Any of the previous I2C_xxx macros will
2437 have GPIO-based defaults assigned to them as appropriate.
2439 You should define these to the GPIO value as given directly to
2440 the generic GPIO functions.
2442 CONFIG_SYS_I2C_INIT_BOARD
2444 When a board is reset during an i2c bus transfer
2445 chips might think that the current transfer is still
2446 in progress. On some boards it is possible to access
2447 the i2c SCLK line directly, either by using the
2448 processor pin as a GPIO or by having a second pin
2449 connected to the bus. If this option is defined a
2450 custom i2c_init_board() routine in boards/xxx/board.c
2451 is run early in the boot sequence.
2453 CONFIG_SYS_I2C_BOARD_LATE_INIT
2455 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2456 defined a custom i2c_board_late_init() routine in
2457 boards/xxx/board.c is run AFTER the operations in i2c_init()
2458 is completed. This callpoint can be used to unreset i2c bus
2459 using CPU i2c controller register accesses for CPUs whose i2c
2460 controller provide such a method. It is called at the end of
2461 i2c_init() to allow i2c_init operations to setup the i2c bus
2462 controller on the CPU (e.g. setting bus speed & slave address).
2464 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2466 This option enables configuration of bi_iic_fast[] flags
2467 in u-boot bd_info structure based on u-boot environment
2468 variable "i2cfast". (see also i2cfast)
2470 CONFIG_I2C_MULTI_BUS
2472 This option allows the use of multiple I2C buses, each of which
2473 must have a controller. At any point in time, only one bus is
2474 active. To switch to a different bus, use the 'i2c dev' command.
2475 Note that bus numbering is zero-based.
2477 CONFIG_SYS_I2C_NOPROBES
2479 This option specifies a list of I2C devices that will be skipped
2480 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2481 is set, specify a list of bus-device pairs. Otherwise, specify
2482 a 1D array of device addresses
2485 #undef CONFIG_I2C_MULTI_BUS
2486 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2488 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2490 #define CONFIG_I2C_MULTI_BUS
2491 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2493 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2495 CONFIG_SYS_SPD_BUS_NUM
2497 If defined, then this indicates the I2C bus number for DDR SPD.
2498 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2500 CONFIG_SYS_RTC_BUS_NUM
2502 If defined, then this indicates the I2C bus number for the RTC.
2503 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2505 CONFIG_SYS_DTT_BUS_NUM
2507 If defined, then this indicates the I2C bus number for the DTT.
2508 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2510 CONFIG_SYS_I2C_DTT_ADDR:
2512 If defined, specifies the I2C address of the DTT device.
2513 If not defined, then U-Boot uses predefined value for
2514 specified DTT device.
2516 CONFIG_SOFT_I2C_READ_REPEATED_START
2518 defining this will force the i2c_read() function in
2519 the soft_i2c driver to perform an I2C repeated start
2520 between writing the address pointer and reading the
2521 data. If this define is omitted the default behaviour
2522 of doing a stop-start sequence will be used. Most I2C
2523 devices can use either method, but some require one or
2526 - SPI Support: CONFIG_SPI
2528 Enables SPI driver (so far only tested with
2529 SPI EEPROM, also an instance works with Crystal A/D and
2530 D/As on the SACSng board)
2534 Enables the driver for SPI controller on SuperH. Currently
2535 only SH7757 is supported.
2539 Enables extended (16-bit) SPI EEPROM addressing.
2540 (symmetrical to CONFIG_I2C_X)
2544 Enables a software (bit-bang) SPI driver rather than
2545 using hardware support. This is a general purpose
2546 driver that only requires three general I/O port pins
2547 (two outputs, one input) to function. If this is
2548 defined, the board configuration must define several
2549 SPI configuration items (port pins to use, etc). For
2550 an example, see include/configs/sacsng.h.
2554 Enables a hardware SPI driver for general-purpose reads
2555 and writes. As with CONFIG_SOFT_SPI, the board configuration
2556 must define a list of chip-select function pointers.
2557 Currently supported on some MPC8xxx processors. For an
2558 example, see include/configs/mpc8349emds.h.
2562 Enables the driver for the SPI controllers on i.MX and MXC
2563 SoCs. Currently i.MX31/35/51 are supported.
2565 - FPGA Support: CONFIG_FPGA
2567 Enables FPGA subsystem.
2569 CONFIG_FPGA_<vendor>
2571 Enables support for specific chip vendors.
2574 CONFIG_FPGA_<family>
2576 Enables support for FPGA family.
2577 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2581 Specify the number of FPGA devices to support.
2583 CONFIG_CMD_FPGA_LOADMK
2585 Enable support for fpga loadmk command
2587 CONFIG_CMD_FPGA_LOADP
2589 Enable support for fpga loadp command - load partial bitstream
2591 CONFIG_CMD_FPGA_LOADBP
2593 Enable support for fpga loadbp command - load partial bitstream
2596 CONFIG_SYS_FPGA_PROG_FEEDBACK
2598 Enable printing of hash marks during FPGA configuration.
2600 CONFIG_SYS_FPGA_CHECK_BUSY
2602 Enable checks on FPGA configuration interface busy
2603 status by the configuration function. This option
2604 will require a board or device specific function to
2609 If defined, a function that provides delays in the FPGA
2610 configuration driver.
2612 CONFIG_SYS_FPGA_CHECK_CTRLC
2613 Allow Control-C to interrupt FPGA configuration
2615 CONFIG_SYS_FPGA_CHECK_ERROR
2617 Check for configuration errors during FPGA bitfile
2618 loading. For example, abort during Virtex II
2619 configuration if the INIT_B line goes low (which
2620 indicated a CRC error).
2622 CONFIG_SYS_FPGA_WAIT_INIT
2624 Maximum time to wait for the INIT_B line to deassert
2625 after PROB_B has been deasserted during a Virtex II
2626 FPGA configuration sequence. The default time is 500
2629 CONFIG_SYS_FPGA_WAIT_BUSY
2631 Maximum time to wait for BUSY to deassert during
2632 Virtex II FPGA configuration. The default is 5 ms.
2634 CONFIG_SYS_FPGA_WAIT_CONFIG
2636 Time to wait after FPGA configuration. The default is
2639 - Configuration Management:
2642 If defined, this string will be added to the U-Boot
2643 version information (U_BOOT_VERSION)
2645 - Vendor Parameter Protection:
2647 U-Boot considers the values of the environment
2648 variables "serial#" (Board Serial Number) and
2649 "ethaddr" (Ethernet Address) to be parameters that
2650 are set once by the board vendor / manufacturer, and
2651 protects these variables from casual modification by
2652 the user. Once set, these variables are read-only,
2653 and write or delete attempts are rejected. You can
2654 change this behaviour:
2656 If CONFIG_ENV_OVERWRITE is #defined in your config
2657 file, the write protection for vendor parameters is
2658 completely disabled. Anybody can change or delete
2661 Alternatively, if you #define _both_ CONFIG_ETHADDR
2662 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2663 Ethernet address is installed in the environment,
2664 which can be changed exactly ONCE by the user. [The
2665 serial# is unaffected by this, i. e. it remains
2668 The same can be accomplished in a more flexible way
2669 for any variable by configuring the type of access
2670 to allow for those variables in the ".flags" variable
2671 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2676 Define this variable to enable the reservation of
2677 "protected RAM", i. e. RAM which is not overwritten
2678 by U-Boot. Define CONFIG_PRAM to hold the number of
2679 kB you want to reserve for pRAM. You can overwrite
2680 this default value by defining an environment
2681 variable "pram" to the number of kB you want to
2682 reserve. Note that the board info structure will
2683 still show the full amount of RAM. If pRAM is
2684 reserved, a new environment variable "mem" will
2685 automatically be defined to hold the amount of
2686 remaining RAM in a form that can be passed as boot
2687 argument to Linux, for instance like that:
2689 setenv bootargs ... mem=\${mem}
2692 This way you can tell Linux not to use this memory,
2693 either, which results in a memory region that will
2694 not be affected by reboots.
2696 *WARNING* If your board configuration uses automatic
2697 detection of the RAM size, you must make sure that
2698 this memory test is non-destructive. So far, the
2699 following board configurations are known to be
2702 IVMS8, IVML24, SPD8xx, TQM8xxL,
2703 HERMES, IP860, RPXlite, LWMON,
2706 - Access to physical memory region (> 4GB)
2707 Some basic support is provided for operations on memory not
2708 normally accessible to U-Boot - e.g. some architectures
2709 support access to more than 4GB of memory on 32-bit
2710 machines using physical address extension or similar.
2711 Define CONFIG_PHYSMEM to access this basic support, which
2712 currently only supports clearing the memory.
2717 Define this variable to stop the system in case of a
2718 fatal error, so that you have to reset it manually.
2719 This is probably NOT a good idea for an embedded
2720 system where you want the system to reboot
2721 automatically as fast as possible, but it may be
2722 useful during development since you can try to debug
2723 the conditions that lead to the situation.
2725 CONFIG_NET_RETRY_COUNT
2727 This variable defines the number of retries for
2728 network operations like ARP, RARP, TFTP, or BOOTP
2729 before giving up the operation. If not defined, a
2730 default value of 5 is used.
2734 Timeout waiting for an ARP reply in milliseconds.
2738 Timeout in milliseconds used in NFS protocol.
2739 If you encounter "ERROR: Cannot umount" in nfs command,
2740 try longer timeout such as
2741 #define CONFIG_NFS_TIMEOUT 10000UL
2743 - Command Interpreter:
2744 CONFIG_AUTO_COMPLETE
2746 Enable auto completion of commands using TAB.
2748 Note that this feature has NOT been implemented yet
2749 for the "hush" shell.
2752 CONFIG_SYS_HUSH_PARSER
2754 Define this variable to enable the "hush" shell (from
2755 Busybox) as command line interpreter, thus enabling
2756 powerful command line syntax like
2757 if...then...else...fi conditionals or `&&' and '||'
2758 constructs ("shell scripts").
2760 If undefined, you get the old, much simpler behaviour
2761 with a somewhat smaller memory footprint.
2764 CONFIG_SYS_PROMPT_HUSH_PS2
2766 This defines the secondary prompt string, which is
2767 printed when the command interpreter needs more input
2768 to complete a command. Usually "> ".
2772 In the current implementation, the local variables
2773 space and global environment variables space are
2774 separated. Local variables are those you define by
2775 simply typing `name=value'. To access a local
2776 variable later on, you have write `$name' or
2777 `${name}'; to execute the contents of a variable
2778 directly type `$name' at the command prompt.
2780 Global environment variables are those you use
2781 setenv/printenv to work with. To run a command stored
2782 in such a variable, you need to use the run command,
2783 and you must not use the '$' sign to access them.
2785 To store commands and special characters in a
2786 variable, please use double quotation marks
2787 surrounding the whole text of the variable, instead
2788 of the backslashes before semicolons and special
2791 - Commandline Editing and History:
2792 CONFIG_CMDLINE_EDITING
2794 Enable editing and History functions for interactive
2795 commandline input operations
2797 - Default Environment:
2798 CONFIG_EXTRA_ENV_SETTINGS
2800 Define this to contain any number of null terminated
2801 strings (variable = value pairs) that will be part of
2802 the default environment compiled into the boot image.
2804 For example, place something like this in your
2805 board's config file:
2807 #define CONFIG_EXTRA_ENV_SETTINGS \
2811 Warning: This method is based on knowledge about the
2812 internal format how the environment is stored by the
2813 U-Boot code. This is NOT an official, exported
2814 interface! Although it is unlikely that this format
2815 will change soon, there is no guarantee either.
2816 You better know what you are doing here.
2818 Note: overly (ab)use of the default environment is
2819 discouraged. Make sure to check other ways to preset
2820 the environment like the "source" command or the
2823 CONFIG_ENV_VARS_UBOOT_CONFIG
2825 Define this in order to add variables describing the
2826 U-Boot build configuration to the default environment.
2827 These will be named arch, cpu, board, vendor, and soc.
2829 Enabling this option will cause the following to be defined:
2837 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2839 Define this in order to add variables describing certain
2840 run-time determined information about the hardware to the
2841 environment. These will be named board_name, board_rev.
2843 CONFIG_DELAY_ENVIRONMENT
2845 Normally the environment is loaded when the board is
2846 intialised so that it is available to U-Boot. This inhibits
2847 that so that the environment is not available until
2848 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2849 this is instead controlled by the value of
2850 /config/load-environment.
2852 - DataFlash Support:
2853 CONFIG_HAS_DATAFLASH
2855 Defining this option enables DataFlash features and
2856 allows to read/write in Dataflash via the standard
2859 - Serial Flash support
2862 Defining this option enables SPI flash commands
2863 'sf probe/read/write/erase/update'.
2865 Usage requires an initial 'probe' to define the serial
2866 flash parameters, followed by read/write/erase/update
2869 The following defaults may be provided by the platform
2870 to handle the common case when only a single serial
2871 flash is present on the system.
2873 CONFIG_SF_DEFAULT_BUS Bus identifier
2874 CONFIG_SF_DEFAULT_CS Chip-select
2875 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2876 CONFIG_SF_DEFAULT_SPEED in Hz
2880 Define this option to include a destructive SPI flash
2883 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2885 Define this option to use the Bank addr/Extended addr
2886 support on SPI flashes which has size > 16Mbytes.
2888 CONFIG_SF_DUAL_FLASH Dual flash memories
2890 Define this option to use dual flash support where two flash
2891 memories can be connected with a given cs line.
2892 currently Xilinx Zynq qspi support these type of connections.
2894 - SystemACE Support:
2897 Adding this option adds support for Xilinx SystemACE
2898 chips attached via some sort of local bus. The address
2899 of the chip must also be defined in the
2900 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2902 #define CONFIG_SYSTEMACE
2903 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2905 When SystemACE support is added, the "ace" device type
2906 becomes available to the fat commands, i.e. fatls.
2908 - TFTP Fixed UDP Port:
2911 If this is defined, the environment variable tftpsrcp
2912 is used to supply the TFTP UDP source port value.
2913 If tftpsrcp isn't defined, the normal pseudo-random port
2914 number generator is used.
2916 Also, the environment variable tftpdstp is used to supply
2917 the TFTP UDP destination port value. If tftpdstp isn't
2918 defined, the normal port 69 is used.
2920 The purpose for tftpsrcp is to allow a TFTP server to
2921 blindly start the TFTP transfer using the pre-configured
2922 target IP address and UDP port. This has the effect of
2923 "punching through" the (Windows XP) firewall, allowing
2924 the remainder of the TFTP transfer to proceed normally.
2925 A better solution is to properly configure the firewall,
2926 but sometimes that is not allowed.
2931 This enables a generic 'hash' command which can produce
2932 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2936 Enable the hash verify command (hash -v). This adds to code
2939 CONFIG_SHA1 - support SHA1 hashing
2940 CONFIG_SHA256 - support SHA256 hashing
2942 Note: There is also a sha1sum command, which should perhaps
2943 be deprecated in favour of 'hash sha1'.
2945 - Freescale i.MX specific commands:
2946 CONFIG_CMD_HDMIDETECT
2947 This enables 'hdmidet' command which returns true if an
2948 HDMI monitor is detected. This command is i.MX 6 specific.
2951 This enables the 'bmode' (bootmode) command for forcing
2952 a boot from specific media.
2954 This is useful for forcing the ROM's usb downloader to
2955 activate upon a watchdog reset which is nice when iterating
2956 on U-Boot. Using the reset button or running bmode normal
2957 will set it back to normal. This command currently
2958 supports i.MX53 and i.MX6.
2963 This enables the RSA algorithm used for FIT image verification
2964 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
2966 The signing part is build into mkimage regardless of this
2969 - bootcount support:
2970 CONFIG_BOOTCOUNT_LIMIT
2972 This enables the bootcounter support, see:
2973 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2976 enable special bootcounter support on at91sam9xe based boards.
2978 enable special bootcounter support on blackfin based boards.
2980 enable special bootcounter support on da850 based boards.
2981 CONFIG_BOOTCOUNT_RAM
2982 enable support for the bootcounter in RAM
2983 CONFIG_BOOTCOUNT_I2C
2984 enable support for the bootcounter on an i2c (like RTC) device.
2985 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2986 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2988 CONFIG_BOOTCOUNT_ALEN = address len
2990 - Show boot progress:
2991 CONFIG_SHOW_BOOT_PROGRESS
2993 Defining this option allows to add some board-
2994 specific code (calling a user-provided function
2995 "show_boot_progress(int)") that enables you to show
2996 the system's boot progress on some display (for
2997 example, some LED's) on your board. At the moment,
2998 the following checkpoints are implemented:
3000 - Detailed boot stage timing
3002 Define this option to get detailed timing of each stage
3003 of the boot process.
3005 CONFIG_BOOTSTAGE_USER_COUNT
3006 This is the number of available user bootstage records.
3007 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3008 a new ID will be allocated from this stash. If you exceed
3009 the limit, recording will stop.
3011 CONFIG_BOOTSTAGE_REPORT
3012 Define this to print a report before boot, similar to this:
3014 Timer summary in microseconds:
3017 3,575,678 3,575,678 board_init_f start
3018 3,575,695 17 arch_cpu_init A9
3019 3,575,777 82 arch_cpu_init done
3020 3,659,598 83,821 board_init_r start
3021 3,910,375 250,777 main_loop
3022 29,916,167 26,005,792 bootm_start
3023 30,361,327 445,160 start_kernel
3025 CONFIG_CMD_BOOTSTAGE
3026 Add a 'bootstage' command which supports printing a report
3027 and un/stashing of bootstage data.
3029 CONFIG_BOOTSTAGE_FDT
3030 Stash the bootstage information in the FDT. A root 'bootstage'
3031 node is created with each bootstage id as a child. Each child
3032 has a 'name' property and either 'mark' containing the
3033 mark time in microsecond, or 'accum' containing the
3034 accumulated time for that bootstage id in microseconds.
3039 name = "board_init_f";
3048 Code in the Linux kernel can find this in /proc/devicetree.
3050 Legacy uImage format:
3053 1 common/cmd_bootm.c before attempting to boot an image
3054 -1 common/cmd_bootm.c Image header has bad magic number
3055 2 common/cmd_bootm.c Image header has correct magic number
3056 -2 common/cmd_bootm.c Image header has bad checksum
3057 3 common/cmd_bootm.c Image header has correct checksum
3058 -3 common/cmd_bootm.c Image data has bad checksum
3059 4 common/cmd_bootm.c Image data has correct checksum
3060 -4 common/cmd_bootm.c Image is for unsupported architecture
3061 5 common/cmd_bootm.c Architecture check OK
3062 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3063 6 common/cmd_bootm.c Image Type check OK
3064 -6 common/cmd_bootm.c gunzip uncompression error
3065 -7 common/cmd_bootm.c Unimplemented compression type
3066 7 common/cmd_bootm.c Uncompression OK
3067 8 common/cmd_bootm.c No uncompress/copy overwrite error
3068 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3070 9 common/image.c Start initial ramdisk verification
3071 -10 common/image.c Ramdisk header has bad magic number
3072 -11 common/image.c Ramdisk header has bad checksum
3073 10 common/image.c Ramdisk header is OK
3074 -12 common/image.c Ramdisk data has bad checksum
3075 11 common/image.c Ramdisk data has correct checksum
3076 12 common/image.c Ramdisk verification complete, start loading
3077 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3078 13 common/image.c Start multifile image verification
3079 14 common/image.c No initial ramdisk, no multifile, continue.
3081 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3083 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3084 -31 post/post.c POST test failed, detected by post_output_backlog()
3085 -32 post/post.c POST test failed, detected by post_run_single()
3087 34 common/cmd_doc.c before loading a Image from a DOC device
3088 -35 common/cmd_doc.c Bad usage of "doc" command
3089 35 common/cmd_doc.c correct usage of "doc" command
3090 -36 common/cmd_doc.c No boot device
3091 36 common/cmd_doc.c correct boot device
3092 -37 common/cmd_doc.c Unknown Chip ID on boot device
3093 37 common/cmd_doc.c correct chip ID found, device available
3094 -38 common/cmd_doc.c Read Error on boot device
3095 38 common/cmd_doc.c reading Image header from DOC device OK
3096 -39 common/cmd_doc.c Image header has bad magic number
3097 39 common/cmd_doc.c Image header has correct magic number
3098 -40 common/cmd_doc.c Error reading Image from DOC device
3099 40 common/cmd_doc.c Image header has correct magic number
3100 41 common/cmd_ide.c before loading a Image from a IDE device
3101 -42 common/cmd_ide.c Bad usage of "ide" command
3102 42 common/cmd_ide.c correct usage of "ide" command
3103 -43 common/cmd_ide.c No boot device
3104 43 common/cmd_ide.c boot device found
3105 -44 common/cmd_ide.c Device not available
3106 44 common/cmd_ide.c Device available
3107 -45 common/cmd_ide.c wrong partition selected
3108 45 common/cmd_ide.c partition selected
3109 -46 common/cmd_ide.c Unknown partition table
3110 46 common/cmd_ide.c valid partition table found
3111 -47 common/cmd_ide.c Invalid partition type
3112 47 common/cmd_ide.c correct partition type
3113 -48 common/cmd_ide.c Error reading Image Header on boot device
3114 48 common/cmd_ide.c reading Image Header from IDE device OK
3115 -49 common/cmd_ide.c Image header has bad magic number
3116 49 common/cmd_ide.c Image header has correct magic number
3117 -50 common/cmd_ide.c Image header has bad checksum
3118 50 common/cmd_ide.c Image header has correct checksum
3119 -51 common/cmd_ide.c Error reading Image from IDE device
3120 51 common/cmd_ide.c reading Image from IDE device OK
3121 52 common/cmd_nand.c before loading a Image from a NAND device
3122 -53 common/cmd_nand.c Bad usage of "nand" command
3123 53 common/cmd_nand.c correct usage of "nand" command
3124 -54 common/cmd_nand.c No boot device
3125 54 common/cmd_nand.c boot device found
3126 -55 common/cmd_nand.c Unknown Chip ID on boot device
3127 55 common/cmd_nand.c correct chip ID found, device available
3128 -56 common/cmd_nand.c Error reading Image Header on boot device
3129 56 common/cmd_nand.c reading Image Header from NAND device OK
3130 -57 common/cmd_nand.c Image header has bad magic number
3131 57 common/cmd_nand.c Image header has correct magic number
3132 -58 common/cmd_nand.c Error reading Image from NAND device
3133 58 common/cmd_nand.c reading Image from NAND device OK
3135 -60 common/env_common.c Environment has a bad CRC, using default
3137 64 net/eth.c starting with Ethernet configuration.
3138 -64 net/eth.c no Ethernet found.
3139 65 net/eth.c Ethernet found.
3141 -80 common/cmd_net.c usage wrong
3142 80 common/cmd_net.c before calling NetLoop()
3143 -81 common/cmd_net.c some error in NetLoop() occurred
3144 81 common/cmd_net.c NetLoop() back without error
3145 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3146 82 common/cmd_net.c trying automatic boot
3147 83 common/cmd_net.c running "source" command
3148 -83 common/cmd_net.c some error in automatic boot or "source" command
3149 84 common/cmd_net.c end without errors
3154 100 common/cmd_bootm.c Kernel FIT Image has correct format
3155 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3156 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3157 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3158 102 common/cmd_bootm.c Kernel unit name specified
3159 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3160 103 common/cmd_bootm.c Found configuration node
3161 104 common/cmd_bootm.c Got kernel subimage node offset
3162 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3163 105 common/cmd_bootm.c Kernel subimage hash verification OK
3164 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3165 106 common/cmd_bootm.c Architecture check OK
3166 -106 common/cmd_bootm.c Kernel subimage has wrong type
3167 107 common/cmd_bootm.c Kernel subimage type OK
3168 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3169 108 common/cmd_bootm.c Got kernel subimage data/size
3170 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3171 -109 common/cmd_bootm.c Can't get kernel subimage type
3172 -110 common/cmd_bootm.c Can't get kernel subimage comp
3173 -111 common/cmd_bootm.c Can't get kernel subimage os
3174 -112 common/cmd_bootm.c Can't get kernel subimage load address
3175 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3177 120 common/image.c Start initial ramdisk verification
3178 -120 common/image.c Ramdisk FIT image has incorrect format
3179 121 common/image.c Ramdisk FIT image has correct format
3180 122 common/image.c No ramdisk subimage unit name, using configuration
3181 -122 common/image.c Can't get configuration for ramdisk subimage
3182 123 common/image.c Ramdisk unit name specified
3183 -124 common/image.c Can't get ramdisk subimage node offset
3184 125 common/image.c Got ramdisk subimage node offset
3185 -125 common/image.c Ramdisk subimage hash verification failed
3186 126 common/image.c Ramdisk subimage hash verification OK
3187 -126 common/image.c Ramdisk subimage for unsupported architecture
3188 127 common/image.c Architecture check OK
3189 -127 common/image.c Can't get ramdisk subimage data/size
3190 128 common/image.c Got ramdisk subimage data/size
3191 129 common/image.c Can't get ramdisk load address
3192 -129 common/image.c Got ramdisk load address
3194 -130 common/cmd_doc.c Incorrect FIT image format
3195 131 common/cmd_doc.c FIT image format OK
3197 -140 common/cmd_ide.c Incorrect FIT image format
3198 141 common/cmd_ide.c FIT image format OK
3200 -150 common/cmd_nand.c Incorrect FIT image format
3201 151 common/cmd_nand.c FIT image format OK
3203 - FIT image support:
3205 Enable support for the FIT uImage format.
3207 CONFIG_FIT_BEST_MATCH
3208 When no configuration is explicitly selected, default to the
3209 one whose fdt's compatibility field best matches that of
3210 U-Boot itself. A match is considered "best" if it matches the
3211 most specific compatibility entry of U-Boot's fdt's root node.
3212 The order of entries in the configuration's fdt is ignored.
3214 CONFIG_FIT_SIGNATURE
3215 This option enables signature verification of FIT uImages,
3216 using a hash signed and verified using RSA. See
3217 doc/uImage.FIT/signature.txt for more details.
3219 - Standalone program support:
3220 CONFIG_STANDALONE_LOAD_ADDR
3222 This option defines a board specific value for the
3223 address where standalone program gets loaded, thus
3224 overwriting the architecture dependent default
3227 - Frame Buffer Address:
3230 Define CONFIG_FB_ADDR if you want to use specific
3231 address for frame buffer. This is typically the case
3232 when using a graphics controller has separate video
3233 memory. U-Boot will then place the frame buffer at
3234 the given address instead of dynamically reserving it
3235 in system RAM by calling lcd_setmem(), which grabs
3236 the memory for the frame buffer depending on the
3237 configured panel size.
3239 Please see board_init_f function.
3241 - Automatic software updates via TFTP server
3243 CONFIG_UPDATE_TFTP_CNT_MAX
3244 CONFIG_UPDATE_TFTP_MSEC_MAX
3246 These options enable and control the auto-update feature;
3247 for a more detailed description refer to doc/README.update.
3249 - MTD Support (mtdparts command, UBI support)
3252 Adds the MTD device infrastructure from the Linux kernel.
3253 Needed for mtdparts command support.
3255 CONFIG_MTD_PARTITIONS
3257 Adds the MTD partitioning infrastructure from the Linux
3258 kernel. Needed for UBI support.
3263 Adds commands for interacting with MTD partitions formatted
3264 with the UBI flash translation layer
3266 Requires also defining CONFIG_RBTREE
3268 CONFIG_UBI_SILENCE_MSG
3270 Make the verbose messages from UBI stop printing. This leaves
3271 warnings and errors enabled.
3276 Adds commands for interacting with UBI volumes formatted as
3277 UBIFS. UBIFS is read-only in u-boot.
3279 Requires UBI support as well as CONFIG_LZO
3281 CONFIG_UBIFS_SILENCE_MSG
3283 Make the verbose messages from UBIFS stop printing. This leaves
3284 warnings and errors enabled.
3288 Enable building of SPL globally.
3291 LDSCRIPT for linking the SPL binary.
3293 CONFIG_SPL_MAX_FOOTPRINT
3294 Maximum size in memory allocated to the SPL, BSS included.
3295 When defined, the linker checks that the actual memory
3296 used by SPL from _start to __bss_end does not exceed it.
3297 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3298 must not be both defined at the same time.
3301 Maximum size of the SPL image (text, data, rodata, and
3302 linker lists sections), BSS excluded.
3303 When defined, the linker checks that the actual size does
3306 CONFIG_SPL_TEXT_BASE
3307 TEXT_BASE for linking the SPL binary.
3309 CONFIG_SPL_RELOC_TEXT_BASE
3310 Address to relocate to. If unspecified, this is equal to
3311 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3313 CONFIG_SPL_BSS_START_ADDR
3314 Link address for the BSS within the SPL binary.
3316 CONFIG_SPL_BSS_MAX_SIZE
3317 Maximum size in memory allocated to the SPL BSS.
3318 When defined, the linker checks that the actual memory used
3319 by SPL from __bss_start to __bss_end does not exceed it.
3320 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3321 must not be both defined at the same time.
3324 Adress of the start of the stack SPL will use
3326 CONFIG_SPL_RELOC_STACK
3327 Adress of the start of the stack SPL will use after
3328 relocation. If unspecified, this is equal to
3331 CONFIG_SYS_SPL_MALLOC_START
3332 Starting address of the malloc pool used in SPL.
3334 CONFIG_SYS_SPL_MALLOC_SIZE
3335 The size of the malloc pool used in SPL.
3337 CONFIG_SPL_FRAMEWORK
3338 Enable the SPL framework under common/. This framework
3339 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3340 NAND loading of the Linux Kernel.
3343 Enable booting directly to an OS from SPL.
3344 See also: doc/README.falcon
3346 CONFIG_SPL_DISPLAY_PRINT
3347 For ARM, enable an optional function to print more information
3348 about the running system.
3350 CONFIG_SPL_INIT_MINIMAL
3351 Arch init code should be built for a very small image
3353 CONFIG_SPL_LIBCOMMON_SUPPORT
3354 Support for common/libcommon.o in SPL binary
3356 CONFIG_SPL_LIBDISK_SUPPORT
3357 Support for disk/libdisk.o in SPL binary
3359 CONFIG_SPL_I2C_SUPPORT
3360 Support for drivers/i2c/libi2c.o in SPL binary
3362 CONFIG_SPL_GPIO_SUPPORT
3363 Support for drivers/gpio/libgpio.o in SPL binary
3365 CONFIG_SPL_MMC_SUPPORT
3366 Support for drivers/mmc/libmmc.o in SPL binary
3368 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3369 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3370 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3371 Address, size and partition on the MMC to load U-Boot from
3372 when the MMC is being used in raw mode.
3374 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3375 Sector to load kernel uImage from when MMC is being
3376 used in raw mode (for Falcon mode)
3378 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3379 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3380 Sector and number of sectors to load kernel argument
3381 parameters from when MMC is being used in raw mode
3384 CONFIG_SPL_FAT_SUPPORT
3385 Support for fs/fat/libfat.o in SPL binary
3387 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3388 Filename to read to load U-Boot when reading from FAT
3390 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3391 Filename to read to load kernel uImage when reading
3392 from FAT (for Falcon mode)
3394 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3395 Filename to read to load kernel argument parameters
3396 when reading from FAT (for Falcon mode)
3398 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3399 Set this for NAND SPL on PPC mpc83xx targets, so that
3400 start.S waits for the rest of the SPL to load before
3401 continuing (the hardware starts execution after just
3402 loading the first page rather than the full 4K).
3404 CONFIG_SPL_SKIP_RELOCATE
3405 Avoid SPL relocation
3407 CONFIG_SPL_NAND_BASE
3408 Include nand_base.c in the SPL. Requires
3409 CONFIG_SPL_NAND_DRIVERS.
3411 CONFIG_SPL_NAND_DRIVERS
3412 SPL uses normal NAND drivers, not minimal drivers.
3415 Include standard software ECC in the SPL
3417 CONFIG_SPL_NAND_SIMPLE
3418 Support for NAND boot using simple NAND drivers that
3419 expose the cmd_ctrl() interface.
3421 CONFIG_SPL_MTD_SUPPORT
3422 Support for the MTD subsystem within SPL. Useful for
3423 environment on NAND support within SPL.
3425 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3426 Set for the SPL on PPC mpc8xxx targets, support for
3427 drivers/ddr/fsl/libddr.o in SPL binary.
3429 CONFIG_SPL_COMMON_INIT_DDR
3430 Set for common ddr init with serial presence detect in
3433 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3434 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3435 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3436 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3437 CONFIG_SYS_NAND_ECCBYTES
3438 Defines the size and behavior of the NAND that SPL uses
3441 CONFIG_SPL_NAND_BOOT
3442 Add support NAND boot
3444 CONFIG_SYS_NAND_U_BOOT_OFFS
3445 Location in NAND to read U-Boot from
3447 CONFIG_SYS_NAND_U_BOOT_DST
3448 Location in memory to load U-Boot to
3450 CONFIG_SYS_NAND_U_BOOT_SIZE
3451 Size of image to load
3453 CONFIG_SYS_NAND_U_BOOT_START
3454 Entry point in loaded image to jump to
3456 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3457 Define this if you need to first read the OOB and then the
3458 data. This is used for example on davinci plattforms.
3460 CONFIG_SPL_OMAP3_ID_NAND
3461 Support for an OMAP3-specific set of functions to return the
3462 ID and MFR of the first attached NAND chip, if present.
3464 CONFIG_SPL_SERIAL_SUPPORT
3465 Support for drivers/serial/libserial.o in SPL binary
3467 CONFIG_SPL_SPI_FLASH_SUPPORT
3468 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3470 CONFIG_SPL_SPI_SUPPORT
3471 Support for drivers/spi/libspi.o in SPL binary
3473 CONFIG_SPL_RAM_DEVICE
3474 Support for running image already present in ram, in SPL binary
3476 CONFIG_SPL_LIBGENERIC_SUPPORT
3477 Support for lib/libgeneric.o in SPL binary
3479 CONFIG_SPL_ENV_SUPPORT
3480 Support for the environment operating in SPL binary
3482 CONFIG_SPL_NET_SUPPORT
3483 Support for the net/libnet.o in SPL binary.
3484 It conflicts with SPL env from storage medium specified by
3485 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3488 Image offset to which the SPL should be padded before appending
3489 the SPL payload. By default, this is defined as
3490 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3491 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3492 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3495 Final target image containing SPL and payload. Some SPLs
3496 use an arch-specific makefile fragment instead, for
3497 example if more than one image needs to be produced.
3499 CONFIG_FIT_SPL_PRINT
3500 Printing information about a FIT image adds quite a bit of
3501 code to SPL. So this is normally disabled in SPL. Use this
3502 option to re-enable it. This will affect the output of the
3503 bootm command when booting a FIT image.
3507 Enable building of TPL globally.
3510 Image offset to which the TPL should be padded before appending
3511 the TPL payload. By default, this is defined as
3512 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3513 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3514 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3519 [so far only for SMDK2400 boards]
3521 - Modem support enable:
3522 CONFIG_MODEM_SUPPORT
3524 - RTS/CTS Flow control enable:
3527 - Modem debug support:
3528 CONFIG_MODEM_SUPPORT_DEBUG
3530 Enables debugging stuff (char screen[1024], dbg())
3531 for modem support. Useful only with BDI2000.
3533 - Interrupt support (PPC):
3535 There are common interrupt_init() and timer_interrupt()
3536 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3537 for CPU specific initialization. interrupt_init_cpu()
3538 should set decrementer_count to appropriate value. If
3539 CPU resets decrementer automatically after interrupt
3540 (ppc4xx) it should set decrementer_count to zero.
3541 timer_interrupt() calls timer_interrupt_cpu() for CPU
3542 specific handling. If board has watchdog / status_led
3543 / other_activity_monitor it works automatically from
3544 general timer_interrupt().
3548 In the target system modem support is enabled when a
3549 specific key (key combination) is pressed during
3550 power-on. Otherwise U-Boot will boot normally
3551 (autoboot). The key_pressed() function is called from
3552 board_init(). Currently key_pressed() is a dummy
3553 function, returning 1 and thus enabling modem
3556 If there are no modem init strings in the
3557 environment, U-Boot proceed to autoboot; the
3558 previous output (banner, info printfs) will be
3561 See also: doc/README.Modem
3563 Board initialization settings:
3564 ------------------------------
3566 During Initialization u-boot calls a number of board specific functions
3567 to allow the preparation of board specific prerequisites, e.g. pin setup
3568 before drivers are initialized. To enable these callbacks the
3569 following configuration macros have to be defined. Currently this is
3570 architecture specific, so please check arch/your_architecture/lib/board.c
3571 typically in board_init_f() and board_init_r().
3573 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3574 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3575 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3576 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3578 Configuration Settings:
3579 -----------------------
3581 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3582 Optionally it can be defined to support 64-bit memory commands.
3584 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3585 undefine this when you're short of memory.
3587 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3588 width of the commands listed in the 'help' command output.
3590 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3591 prompt for user input.
3593 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3595 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3597 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3599 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3600 the application (usually a Linux kernel) when it is
3603 - CONFIG_SYS_BAUDRATE_TABLE:
3604 List of legal baudrate settings for this board.
3606 - CONFIG_SYS_CONSOLE_INFO_QUIET
3607 Suppress display of console information at boot.
3609 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3610 If the board specific function
3611 extern int overwrite_console (void);
3612 returns 1, the stdin, stderr and stdout are switched to the
3613 serial port, else the settings in the environment are used.
3615 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3616 Enable the call to overwrite_console().
3618 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3619 Enable overwrite of previous console environment settings.
3621 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3622 Begin and End addresses of the area used by the
3625 - CONFIG_SYS_ALT_MEMTEST:
3626 Enable an alternate, more extensive memory test.
3628 - CONFIG_SYS_MEMTEST_SCRATCH:
3629 Scratch address used by the alternate memory test
3630 You only need to set this if address zero isn't writeable
3632 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3633 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3634 this specified memory area will get subtracted from the top
3635 (end) of RAM and won't get "touched" at all by U-Boot. By
3636 fixing up gd->ram_size the Linux kernel should gets passed
3637 the now "corrected" memory size and won't touch it either.
3638 This should work for arch/ppc and arch/powerpc. Only Linux
3639 board ports in arch/powerpc with bootwrapper support that
3640 recalculate the memory size from the SDRAM controller setup
3641 will have to get fixed in Linux additionally.
3643 This option can be used as a workaround for the 440EPx/GRx
3644 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3647 WARNING: Please make sure that this value is a multiple of
3648 the Linux page size (normally 4k). If this is not the case,
3649 then the end address of the Linux memory will be located at a
3650 non page size aligned address and this could cause major
3653 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3654 Enable temporary baudrate change while serial download
3656 - CONFIG_SYS_SDRAM_BASE:
3657 Physical start address of SDRAM. _Must_ be 0 here.
3659 - CONFIG_SYS_MBIO_BASE:
3660 Physical start address of Motherboard I/O (if using a
3663 - CONFIG_SYS_FLASH_BASE:
3664 Physical start address of Flash memory.
3666 - CONFIG_SYS_MONITOR_BASE:
3667 Physical start address of boot monitor code (set by
3668 make config files to be same as the text base address
3669 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3670 CONFIG_SYS_FLASH_BASE when booting from flash.
3672 - CONFIG_SYS_MONITOR_LEN:
3673 Size of memory reserved for monitor code, used to
3674 determine _at_compile_time_ (!) if the environment is
3675 embedded within the U-Boot image, or in a separate
3678 - CONFIG_SYS_MALLOC_LEN:
3679 Size of DRAM reserved for malloc() use.
3681 - CONFIG_SYS_BOOTM_LEN:
3682 Normally compressed uImages are limited to an
3683 uncompressed size of 8 MBytes. If this is not enough,
3684 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3685 to adjust this setting to your needs.
3687 - CONFIG_SYS_BOOTMAPSZ:
3688 Maximum size of memory mapped by the startup code of
3689 the Linux kernel; all data that must be processed by
3690 the Linux kernel (bd_info, boot arguments, FDT blob if
3691 used) must be put below this limit, unless "bootm_low"
3692 environment variable is defined and non-zero. In such case
3693 all data for the Linux kernel must be between "bootm_low"
3694 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3695 variable "bootm_mapsize" will override the value of
3696 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3697 then the value in "bootm_size" will be used instead.
3699 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3700 Enable initrd_high functionality. If defined then the
3701 initrd_high feature is enabled and the bootm ramdisk subcommand
3704 - CONFIG_SYS_BOOT_GET_CMDLINE:
3705 Enables allocating and saving kernel cmdline in space between
3706 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3708 - CONFIG_SYS_BOOT_GET_KBD:
3709 Enables allocating and saving a kernel copy of the bd_info in
3710 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3712 - CONFIG_SYS_MAX_FLASH_BANKS:
3713 Max number of Flash memory banks
3715 - CONFIG_SYS_MAX_FLASH_SECT:
3716 Max number of sectors on a Flash chip
3718 - CONFIG_SYS_FLASH_ERASE_TOUT:
3719 Timeout for Flash erase operations (in ms)
3721 - CONFIG_SYS_FLASH_WRITE_TOUT:
3722 Timeout for Flash write operations (in ms)
3724 - CONFIG_SYS_FLASH_LOCK_TOUT
3725 Timeout for Flash set sector lock bit operation (in ms)
3727 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3728 Timeout for Flash clear lock bits operation (in ms)
3730 - CONFIG_SYS_FLASH_PROTECTION
3731 If defined, hardware flash sectors protection is used
3732 instead of U-Boot software protection.
3734 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3736 Enable TFTP transfers directly to flash memory;
3737 without this option such a download has to be
3738 performed in two steps: (1) download to RAM, and (2)
3739 copy from RAM to flash.
3741 The two-step approach is usually more reliable, since
3742 you can check if the download worked before you erase
3743 the flash, but in some situations (when system RAM is
3744 too limited to allow for a temporary copy of the
3745 downloaded image) this option may be very useful.
3747 - CONFIG_SYS_FLASH_CFI:
3748 Define if the flash driver uses extra elements in the
3749 common flash structure for storing flash geometry.
3751 - CONFIG_FLASH_CFI_DRIVER
3752 This option also enables the building of the cfi_flash driver
3753 in the drivers directory
3755 - CONFIG_FLASH_CFI_MTD
3756 This option enables the building of the cfi_mtd driver
3757 in the drivers directory. The driver exports CFI flash
3760 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3761 Use buffered writes to flash.
3763 - CONFIG_FLASH_SPANSION_S29WS_N
3764 s29ws-n MirrorBit flash has non-standard addresses for buffered
3767 - CONFIG_SYS_FLASH_QUIET_TEST
3768 If this option is defined, the common CFI flash doesn't
3769 print it's warning upon not recognized FLASH banks. This
3770 is useful, if some of the configured banks are only
3771 optionally available.
3773 - CONFIG_FLASH_SHOW_PROGRESS
3774 If defined (must be an integer), print out countdown
3775 digits and dots. Recommended value: 45 (9..1) for 80
3776 column displays, 15 (3..1) for 40 column displays.
3778 - CONFIG_FLASH_VERIFY
3779 If defined, the content of the flash (destination) is compared
3780 against the source after the write operation. An error message
3781 will be printed when the contents are not identical.
3782 Please note that this option is useless in nearly all cases,
3783 since such flash programming errors usually are detected earlier
3784 while unprotecting/erasing/programming. Please only enable
3785 this option if you really know what you are doing.
3787 - CONFIG_SYS_RX_ETH_BUFFER:
3788 Defines the number of Ethernet receive buffers. On some
3789 Ethernet controllers it is recommended to set this value
3790 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3791 buffers can be full shortly after enabling the interface
3792 on high Ethernet traffic.
3793 Defaults to 4 if not defined.
3795 - CONFIG_ENV_MAX_ENTRIES
3797 Maximum number of entries in the hash table that is used
3798 internally to store the environment settings. The default
3799 setting is supposed to be generous and should work in most
3800 cases. This setting can be used to tune behaviour; see
3801 lib/hashtable.c for details.
3803 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3804 - CONFIG_ENV_FLAGS_LIST_STATIC
3805 Enable validation of the values given to environment variables when
3806 calling env set. Variables can be restricted to only decimal,
3807 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3808 the variables can also be restricted to IP address or MAC address.
3810 The format of the list is:
3811 type_attribute = [s|d|x|b|i|m]
3812 access_atribute = [a|r|o|c]
3813 attributes = type_attribute[access_atribute]
3814 entry = variable_name[:attributes]
3817 The type attributes are:
3818 s - String (default)
3821 b - Boolean ([1yYtT|0nNfF])
3825 The access attributes are:
3831 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3832 Define this to a list (string) to define the ".flags"
3833 envirnoment variable in the default or embedded environment.
3835 - CONFIG_ENV_FLAGS_LIST_STATIC
3836 Define this to a list (string) to define validation that
3837 should be done if an entry is not found in the ".flags"
3838 environment variable. To override a setting in the static
3839 list, simply add an entry for the same variable name to the
3842 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3843 If defined, don't allow the -f switch to env set override variable
3846 - CONFIG_SYS_GENERIC_BOARD
3847 This selects the architecture-generic board system instead of the
3848 architecture-specific board files. It is intended to move boards
3849 to this new framework over time. Defining this will disable the
3850 arch/foo/lib/board.c file and use common/board_f.c and
3851 common/board_r.c instead. To use this option your architecture
3852 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3853 its config.mk file). If you find problems enabling this option on
3854 your board please report the problem and send patches!
3856 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3857 This is set by OMAP boards for the max time that reset should
3858 be asserted. See doc/README.omap-reset-time for details on how
3859 the value can be calulated on a given board.
3861 The following definitions that deal with the placement and management
3862 of environment data (variable area); in general, we support the
3863 following configurations:
3865 - CONFIG_BUILD_ENVCRC:
3867 Builds up envcrc with the target environment so that external utils
3868 may easily extract it and embed it in final U-Boot images.
3870 - CONFIG_ENV_IS_IN_FLASH:
3872 Define this if the environment is in flash memory.
3874 a) The environment occupies one whole flash sector, which is
3875 "embedded" in the text segment with the U-Boot code. This
3876 happens usually with "bottom boot sector" or "top boot
3877 sector" type flash chips, which have several smaller
3878 sectors at the start or the end. For instance, such a
3879 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3880 such a case you would place the environment in one of the
3881 4 kB sectors - with U-Boot code before and after it. With
3882 "top boot sector" type flash chips, you would put the
3883 environment in one of the last sectors, leaving a gap
3884 between U-Boot and the environment.
3886 - CONFIG_ENV_OFFSET:
3888 Offset of environment data (variable area) to the
3889 beginning of flash memory; for instance, with bottom boot
3890 type flash chips the second sector can be used: the offset
3891 for this sector is given here.
3893 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3897 This is just another way to specify the start address of
3898 the flash sector containing the environment (instead of
3901 - CONFIG_ENV_SECT_SIZE:
3903 Size of the sector containing the environment.
3906 b) Sometimes flash chips have few, equal sized, BIG sectors.
3907 In such a case you don't want to spend a whole sector for
3912 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3913 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3914 of this flash sector for the environment. This saves
3915 memory for the RAM copy of the environment.
3917 It may also save flash memory if you decide to use this
3918 when your environment is "embedded" within U-Boot code,
3919 since then the remainder of the flash sector could be used
3920 for U-Boot code. It should be pointed out that this is
3921 STRONGLY DISCOURAGED from a robustness point of view:
3922 updating the environment in flash makes it always
3923 necessary to erase the WHOLE sector. If something goes
3924 wrong before the contents has been restored from a copy in
3925 RAM, your target system will be dead.
3927 - CONFIG_ENV_ADDR_REDUND
3928 CONFIG_ENV_SIZE_REDUND
3930 These settings describe a second storage area used to hold
3931 a redundant copy of the environment data, so that there is
3932 a valid backup copy in case there is a power failure during
3933 a "saveenv" operation.
3935 BE CAREFUL! Any changes to the flash layout, and some changes to the
3936 source code will make it necessary to adapt <board>/u-boot.lds*
3940 - CONFIG_ENV_IS_IN_NVRAM:
3942 Define this if you have some non-volatile memory device
3943 (NVRAM, battery buffered SRAM) which you want to use for the
3949 These two #defines are used to determine the memory area you
3950 want to use for environment. It is assumed that this memory
3951 can just be read and written to, without any special
3954 BE CAREFUL! The first access to the environment happens quite early
3955 in U-Boot initalization (when we try to get the setting of for the
3956 console baudrate). You *MUST* have mapped your NVRAM area then, or
3959 Please note that even with NVRAM we still use a copy of the
3960 environment in RAM: we could work on NVRAM directly, but we want to
3961 keep settings there always unmodified except somebody uses "saveenv"
3962 to save the current settings.
3965 - CONFIG_ENV_IS_IN_EEPROM:
3967 Use this if you have an EEPROM or similar serial access
3968 device and a driver for it.
3970 - CONFIG_ENV_OFFSET:
3973 These two #defines specify the offset and size of the
3974 environment area within the total memory of your EEPROM.
3976 - CONFIG_SYS_I2C_EEPROM_ADDR:
3977 If defined, specified the chip address of the EEPROM device.
3978 The default address is zero.
3980 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3981 If defined, the number of bits used to address bytes in a
3982 single page in the EEPROM device. A 64 byte page, for example
3983 would require six bits.
3985 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3986 If defined, the number of milliseconds to delay between
3987 page writes. The default is zero milliseconds.
3989 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3990 The length in bytes of the EEPROM memory array address. Note
3991 that this is NOT the chip address length!
3993 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3994 EEPROM chips that implement "address overflow" are ones
3995 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3996 address and the extra bits end up in the "chip address" bit
3997 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4000 Note that we consider the length of the address field to
4001 still be one byte because the extra address bits are hidden
4002 in the chip address.
4004 - CONFIG_SYS_EEPROM_SIZE:
4005 The size in bytes of the EEPROM device.
4007 - CONFIG_ENV_EEPROM_IS_ON_I2C
4008 define this, if you have I2C and SPI activated, and your
4009 EEPROM, which holds the environment, is on the I2C bus.
4011 - CONFIG_I2C_ENV_EEPROM_BUS
4012 if you have an Environment on an EEPROM reached over
4013 I2C muxes, you can define here, how to reach this
4014 EEPROM. For example:
4016 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4018 EEPROM which holds the environment, is reached over
4019 a pca9547 i2c mux with address 0x70, channel 3.
4021 - CONFIG_ENV_IS_IN_DATAFLASH:
4023 Define this if you have a DataFlash memory device which you
4024 want to use for the environment.
4026 - CONFIG_ENV_OFFSET:
4030 These three #defines specify the offset and size of the
4031 environment area within the total memory of your DataFlash placed
4032 at the specified address.
4034 - CONFIG_ENV_IS_IN_REMOTE:
4036 Define this if you have a remote memory space which you
4037 want to use for the local device's environment.
4042 These two #defines specify the address and size of the
4043 environment area within the remote memory space. The
4044 local device can get the environment from remote memory
4045 space by SRIO or PCIE links.
4047 BE CAREFUL! For some special cases, the local device can not use
4048 "saveenv" command. For example, the local device will get the
4049 environment stored in a remote NOR flash by SRIO or PCIE link,
4050 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4052 - CONFIG_ENV_IS_IN_NAND:
4054 Define this if you have a NAND device which you want to use
4055 for the environment.
4057 - CONFIG_ENV_OFFSET:
4060 These two #defines specify the offset and size of the environment
4061 area within the first NAND device. CONFIG_ENV_OFFSET must be
4062 aligned to an erase block boundary.
4064 - CONFIG_ENV_OFFSET_REDUND (optional):
4066 This setting describes a second storage area of CONFIG_ENV_SIZE
4067 size used to hold a redundant copy of the environment data, so
4068 that there is a valid backup copy in case there is a power failure
4069 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4070 aligned to an erase block boundary.
4072 - CONFIG_ENV_RANGE (optional):
4074 Specifies the length of the region in which the environment
4075 can be written. This should be a multiple of the NAND device's
4076 block size. Specifying a range with more erase blocks than
4077 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4078 the range to be avoided.
4080 - CONFIG_ENV_OFFSET_OOB (optional):
4082 Enables support for dynamically retrieving the offset of the
4083 environment from block zero's out-of-band data. The
4084 "nand env.oob" command can be used to record this offset.
4085 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4086 using CONFIG_ENV_OFFSET_OOB.
4088 - CONFIG_NAND_ENV_DST
4090 Defines address in RAM to which the nand_spl code should copy the
4091 environment. If redundant environment is used, it will be copied to
4092 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4094 - CONFIG_ENV_IS_IN_UBI:
4096 Define this if you have an UBI volume that you want to use for the
4097 environment. This has the benefit of wear-leveling the environment
4098 accesses, which is important on NAND.
4100 - CONFIG_ENV_UBI_PART:
4102 Define this to a string that is the mtd partition containing the UBI.
4104 - CONFIG_ENV_UBI_VOLUME:
4106 Define this to the name of the volume that you want to store the
4109 - CONFIG_ENV_UBI_VOLUME_REDUND:
4111 Define this to the name of another volume to store a second copy of
4112 the environment in. This will enable redundant environments in UBI.
4113 It is assumed that both volumes are in the same MTD partition.
4115 - CONFIG_UBI_SILENCE_MSG
4116 - CONFIG_UBIFS_SILENCE_MSG
4118 You will probably want to define these to avoid a really noisy system
4119 when storing the env in UBI.
4121 - CONFIG_ENV_IS_IN_MMC:
4123 Define this if you have an MMC device which you want to use for the
4126 - CONFIG_SYS_MMC_ENV_DEV:
4128 Specifies which MMC device the environment is stored in.
4130 - CONFIG_SYS_MMC_ENV_PART (optional):
4132 Specifies which MMC partition the environment is stored in. If not
4133 set, defaults to partition 0, the user area. Common values might be
4134 1 (first MMC boot partition), 2 (second MMC boot partition).
4136 - CONFIG_ENV_OFFSET:
4139 These two #defines specify the offset and size of the environment
4140 area within the specified MMC device.
4142 If offset is positive (the usual case), it is treated as relative to
4143 the start of the MMC partition. If offset is negative, it is treated
4144 as relative to the end of the MMC partition. This can be useful if
4145 your board may be fitted with different MMC devices, which have
4146 different sizes for the MMC partitions, and you always want the
4147 environment placed at the very end of the partition, to leave the
4148 maximum possible space before it, to store other data.
4150 These two values are in units of bytes, but must be aligned to an
4151 MMC sector boundary.
4153 - CONFIG_ENV_OFFSET_REDUND (optional):
4155 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4156 hold a redundant copy of the environment data. This provides a
4157 valid backup copy in case the other copy is corrupted, e.g. due
4158 to a power failure during a "saveenv" operation.
4160 This value may also be positive or negative; this is handled in the
4161 same way as CONFIG_ENV_OFFSET.
4163 This value is also in units of bytes, but must also be aligned to
4164 an MMC sector boundary.
4166 - CONFIG_ENV_SIZE_REDUND (optional):
4168 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4169 set. If this value is set, it must be set to the same value as
4172 - CONFIG_SYS_SPI_INIT_OFFSET
4174 Defines offset to the initial SPI buffer area in DPRAM. The
4175 area is used at an early stage (ROM part) if the environment
4176 is configured to reside in the SPI EEPROM: We need a 520 byte
4177 scratch DPRAM area. It is used between the two initialization
4178 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4179 to be a good choice since it makes it far enough from the
4180 start of the data area as well as from the stack pointer.
4182 Please note that the environment is read-only until the monitor
4183 has been relocated to RAM and a RAM copy of the environment has been
4184 created; also, when using EEPROM you will have to use getenv_f()
4185 until then to read environment variables.
4187 The environment is protected by a CRC32 checksum. Before the monitor
4188 is relocated into RAM, as a result of a bad CRC you will be working
4189 with the compiled-in default environment - *silently*!!! [This is
4190 necessary, because the first environment variable we need is the
4191 "baudrate" setting for the console - if we have a bad CRC, we don't
4192 have any device yet where we could complain.]
4194 Note: once the monitor has been relocated, then it will complain if
4195 the default environment is used; a new CRC is computed as soon as you
4196 use the "saveenv" command to store a valid environment.
4198 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4199 Echo the inverted Ethernet link state to the fault LED.
4201 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4202 also needs to be defined.
4204 - CONFIG_SYS_FAULT_MII_ADDR:
4205 MII address of the PHY to check for the Ethernet link state.
4207 - CONFIG_NS16550_MIN_FUNCTIONS:
4208 Define this if you desire to only have use of the NS16550_init
4209 and NS16550_putc functions for the serial driver located at
4210 drivers/serial/ns16550.c. This option is useful for saving
4211 space for already greatly restricted images, including but not
4212 limited to NAND_SPL configurations.
4214 - CONFIG_DISPLAY_BOARDINFO
4215 Display information about the board that U-Boot is running on
4216 when U-Boot starts up. The board function checkboard() is called
4219 - CONFIG_DISPLAY_BOARDINFO_LATE
4220 Similar to the previous option, but display this information
4221 later, once stdio is running and output goes to the LCD, if
4224 Low Level (hardware related) configuration options:
4225 ---------------------------------------------------
4227 - CONFIG_SYS_CACHELINE_SIZE:
4228 Cache Line Size of the CPU.
4230 - CONFIG_SYS_DEFAULT_IMMR:
4231 Default address of the IMMR after system reset.
4233 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4234 and RPXsuper) to be able to adjust the position of
4235 the IMMR register after a reset.
4237 - CONFIG_SYS_CCSRBAR_DEFAULT:
4238 Default (power-on reset) physical address of CCSR on Freescale
4241 - CONFIG_SYS_CCSRBAR:
4242 Virtual address of CCSR. On a 32-bit build, this is typically
4243 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4245 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4246 for cross-platform code that uses that macro instead.
4248 - CONFIG_SYS_CCSRBAR_PHYS:
4249 Physical address of CCSR. CCSR can be relocated to a new
4250 physical address, if desired. In this case, this macro should
4251 be set to that address. Otherwise, it should be set to the
4252 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4253 is typically relocated on 36-bit builds. It is recommended
4254 that this macro be defined via the _HIGH and _LOW macros:
4256 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4257 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4259 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4260 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4261 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4262 used in assembly code, so it must not contain typecasts or
4263 integer size suffixes (e.g. "ULL").
4265 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4266 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4267 used in assembly code, so it must not contain typecasts or
4268 integer size suffixes (e.g. "ULL").
4270 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4271 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4272 forced to a value that ensures that CCSR is not relocated.
4274 - Floppy Disk Support:
4275 CONFIG_SYS_FDC_DRIVE_NUMBER
4277 the default drive number (default value 0)
4279 CONFIG_SYS_ISA_IO_STRIDE
4281 defines the spacing between FDC chipset registers
4284 CONFIG_SYS_ISA_IO_OFFSET
4286 defines the offset of register from address. It
4287 depends on which part of the data bus is connected to
4288 the FDC chipset. (default value 0)
4290 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4291 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4294 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4295 fdc_hw_init() is called at the beginning of the FDC
4296 setup. fdc_hw_init() must be provided by the board
4297 source code. It is used to make hardware dependant
4301 Most IDE controllers were designed to be connected with PCI
4302 interface. Only few of them were designed for AHB interface.
4303 When software is doing ATA command and data transfer to
4304 IDE devices through IDE-AHB controller, some additional
4305 registers accessing to these kind of IDE-AHB controller
4308 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4309 DO NOT CHANGE unless you know exactly what you're
4310 doing! (11-4) [MPC8xx/82xx systems only]
4312 - CONFIG_SYS_INIT_RAM_ADDR:
4314 Start address of memory area that can be used for
4315 initial data and stack; please note that this must be
4316 writable memory that is working WITHOUT special
4317 initialization, i. e. you CANNOT use normal RAM which
4318 will become available only after programming the
4319 memory controller and running certain initialization
4322 U-Boot uses the following memory types:
4323 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4324 - MPC824X: data cache
4325 - PPC4xx: data cache
4327 - CONFIG_SYS_GBL_DATA_OFFSET:
4329 Offset of the initial data structure in the memory
4330 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4331 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4332 data is located at the end of the available space
4333 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4334 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4335 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4336 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4339 On the MPC824X (or other systems that use the data
4340 cache for initial memory) the address chosen for
4341 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4342 point to an otherwise UNUSED address space between
4343 the top of RAM and the start of the PCI space.
4345 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4347 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4349 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4351 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4353 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4355 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4357 - CONFIG_SYS_OR_TIMING_SDRAM:
4360 - CONFIG_SYS_MAMR_PTA:
4361 periodic timer for refresh
4363 - CONFIG_SYS_DER: Debug Event Register (37-47)
4365 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4366 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4367 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4368 CONFIG_SYS_BR1_PRELIM:
4369 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4371 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4372 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4373 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4374 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4376 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4377 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4378 Machine Mode Register and Memory Periodic Timer
4379 Prescaler definitions (SDRAM timing)
4381 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4382 enable I2C microcode relocation patch (MPC8xx);
4383 define relocation offset in DPRAM [DSP2]
4385 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4386 enable SMC microcode relocation patch (MPC8xx);
4387 define relocation offset in DPRAM [SMC1]
4389 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4390 enable SPI microcode relocation patch (MPC8xx);
4391 define relocation offset in DPRAM [SCC4]
4393 - CONFIG_SYS_USE_OSCCLK:
4394 Use OSCM clock mode on MBX8xx board. Be careful,
4395 wrong setting might damage your board. Read
4396 doc/README.MBX before setting this variable!
4398 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4399 Offset of the bootmode word in DPRAM used by post
4400 (Power On Self Tests). This definition overrides
4401 #define'd default value in commproc.h resp.
4404 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4405 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4406 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4407 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4408 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4409 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4410 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4411 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4412 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4414 - CONFIG_PCI_DISABLE_PCIE:
4415 Disable PCI-Express on systems where it is supported but not
4418 - CONFIG_PCI_ENUM_ONLY
4419 Only scan through and get the devices on the busses.
4420 Don't do any setup work, presumably because someone or
4421 something has already done it, and we don't need to do it
4422 a second time. Useful for platforms that are pre-booted
4423 by coreboot or similar.
4425 - CONFIG_PCI_INDIRECT_BRIDGE:
4426 Enable support for indirect PCI bridges.
4429 Chip has SRIO or not
4432 Board has SRIO 1 port available
4435 Board has SRIO 2 port available
4437 - CONFIG_SRIO_PCIE_BOOT_MASTER
4438 Board can support master function for Boot from SRIO and PCIE
4440 - CONFIG_SYS_SRIOn_MEM_VIRT:
4441 Virtual Address of SRIO port 'n' memory region
4443 - CONFIG_SYS_SRIOn_MEM_PHYS:
4444 Physical Address of SRIO port 'n' memory region
4446 - CONFIG_SYS_SRIOn_MEM_SIZE:
4447 Size of SRIO port 'n' memory region
4449 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4450 Defined to tell the NAND controller that the NAND chip is using
4452 Not all NAND drivers use this symbol.
4453 Example of drivers that use it:
4454 - drivers/mtd/nand/ndfc.c
4455 - drivers/mtd/nand/mxc_nand.c
4457 - CONFIG_SYS_NDFC_EBC0_CFG
4458 Sets the EBC0_CFG register for the NDFC. If not defined
4459 a default value will be used.
4462 Get DDR timing information from an I2C EEPROM. Common
4463 with pluggable memory modules such as SODIMMs
4466 I2C address of the SPD EEPROM
4468 - CONFIG_SYS_SPD_BUS_NUM
4469 If SPD EEPROM is on an I2C bus other than the first
4470 one, specify here. Note that the value must resolve
4471 to something your driver can deal with.
4473 - CONFIG_SYS_DDR_RAW_TIMING
4474 Get DDR timing information from other than SPD. Common with
4475 soldered DDR chips onboard without SPD. DDR raw timing
4476 parameters are extracted from datasheet and hard-coded into
4477 header files or board specific files.
4479 - CONFIG_FSL_DDR_INTERACTIVE
4480 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4482 - CONFIG_SYS_83XX_DDR_USES_CS0
4483 Only for 83xx systems. If specified, then DDR should
4484 be configured using CS0 and CS1 instead of CS2 and CS3.
4486 - CONFIG_ETHER_ON_FEC[12]
4487 Define to enable FEC[12] on a 8xx series processor.
4489 - CONFIG_FEC[12]_PHY
4490 Define to the hardcoded PHY address which corresponds
4491 to the given FEC; i. e.
4492 #define CONFIG_FEC1_PHY 4
4493 means that the PHY with address 4 is connected to FEC1
4495 When set to -1, means to probe for first available.
4497 - CONFIG_FEC[12]_PHY_NORXERR
4498 The PHY does not have a RXERR line (RMII only).
4499 (so program the FEC to ignore it).
4502 Enable RMII mode for all FECs.
4503 Note that this is a global option, we can't
4504 have one FEC in standard MII mode and another in RMII mode.
4506 - CONFIG_CRC32_VERIFY
4507 Add a verify option to the crc32 command.
4510 => crc32 -v <address> <count> <crc32>
4512 Where address/count indicate a memory area
4513 and crc32 is the correct crc32 which the
4517 Add the "loopw" memory command. This only takes effect if
4518 the memory commands are activated globally (CONFIG_CMD_MEM).
4521 Add the "mdc" and "mwc" memory commands. These are cyclic
4526 This command will print 4 bytes (10,11,12,13) each 500 ms.
4528 => mwc.l 100 12345678 10
4529 This command will write 12345678 to address 100 all 10 ms.
4531 This only takes effect if the memory commands are activated
4532 globally (CONFIG_CMD_MEM).
4534 - CONFIG_SKIP_LOWLEVEL_INIT
4535 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4536 low level initializations (like setting up the memory
4537 controller) are omitted and/or U-Boot does not
4538 relocate itself into RAM.
4540 Normally this variable MUST NOT be defined. The only
4541 exception is when U-Boot is loaded (to RAM) by some
4542 other boot loader or by a debugger which performs
4543 these initializations itself.
4546 Modifies the behaviour of start.S when compiling a loader
4547 that is executed before the actual U-Boot. E.g. when
4548 compiling a NAND SPL.
4551 Modifies the behaviour of start.S when compiling a loader
4552 that is executed after the SPL and before the actual U-Boot.
4553 It is loaded by the SPL.
4555 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4556 Only for 85xx systems. If this variable is specified, the section
4557 .resetvec is not kept and the section .bootpg is placed in the
4558 previous 4k of the .text section.
4560 - CONFIG_ARCH_MAP_SYSMEM
4561 Generally U-Boot (and in particular the md command) uses
4562 effective address. It is therefore not necessary to regard
4563 U-Boot address as virtual addresses that need to be translated
4564 to physical addresses. However, sandbox requires this, since
4565 it maintains its own little RAM buffer which contains all
4566 addressable memory. This option causes some memory accesses
4567 to be mapped through map_sysmem() / unmap_sysmem().
4569 - CONFIG_USE_ARCH_MEMCPY
4570 CONFIG_USE_ARCH_MEMSET
4571 If these options are used a optimized version of memcpy/memset will
4572 be used if available. These functions may be faster under some
4573 conditions but may increase the binary size.
4575 - CONFIG_X86_RESET_VECTOR
4576 If defined, the x86 reset vector code is included. This is not
4577 needed when U-Boot is running from Coreboot.
4580 Defines the MPU clock speed (in MHz).
4582 NOTE : currently only supported on AM335x platforms.
4584 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4585 Enables the RTC32K OSC on AM33xx based plattforms
4587 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4588 Option to disable subpage write in NAND driver
4589 driver that uses this:
4590 drivers/mtd/nand/davinci_nand.c
4592 Freescale QE/FMAN Firmware Support:
4593 -----------------------------------
4595 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4596 loading of "firmware", which is encoded in the QE firmware binary format.
4597 This firmware often needs to be loaded during U-Boot booting, so macros
4598 are used to identify the storage device (NOR flash, SPI, etc) and the address
4601 - CONFIG_SYS_FMAN_FW_ADDR
4602 The address in the storage device where the FMAN microcode is located. The
4603 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4606 - CONFIG_SYS_QE_FW_ADDR
4607 The address in the storage device where the QE microcode is located. The
4608 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4611 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4612 The maximum possible size of the firmware. The firmware binary format
4613 has a field that specifies the actual size of the firmware, but it
4614 might not be possible to read any part of the firmware unless some
4615 local storage is allocated to hold the entire firmware first.
4617 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4618 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4619 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4620 virtual address in NOR flash.
4622 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4623 Specifies that QE/FMAN firmware is located in NAND flash.
4624 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4626 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4627 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4628 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4630 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4631 Specifies that QE/FMAN firmware is located on the primary SPI
4632 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4634 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4635 Specifies that QE/FMAN firmware is located in the remote (master)
4636 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4637 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4638 window->master inbound window->master LAW->the ucode address in
4639 master's memory space.
4641 Building the Software:
4642 ======================
4644 Building U-Boot has been tested in several native build environments
4645 and in many different cross environments. Of course we cannot support
4646 all possibly existing versions of cross development tools in all
4647 (potentially obsolete) versions. In case of tool chain problems we
4648 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4649 which is extensively used to build and test U-Boot.
4651 If you are not using a native environment, it is assumed that you
4652 have GNU cross compiling tools available in your path. In this case,
4653 you must set the environment variable CROSS_COMPILE in your shell.
4654 Note that no changes to the Makefile or any other source files are
4655 necessary. For example using the ELDK on a 4xx CPU, please enter:
4657 $ CROSS_COMPILE=ppc_4xx-
4658 $ export CROSS_COMPILE
4660 Note: If you wish to generate Windows versions of the utilities in
4661 the tools directory you can use the MinGW toolchain
4662 (http://www.mingw.org). Set your HOST tools to the MinGW
4663 toolchain and execute 'make tools'. For example:
4665 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4667 Binaries such as tools/mkimage.exe will be created which can
4668 be executed on computers running Windows.
4670 U-Boot is intended to be simple to build. After installing the
4671 sources you must configure U-Boot for one specific board type. This
4676 where "NAME_config" is the name of one of the existing configu-
4677 rations; see boards.cfg for supported names.
4679 Note: for some board special configuration names may exist; check if
4680 additional information is available from the board vendor; for
4681 instance, the TQM823L systems are available without (standard)
4682 or with LCD support. You can select such additional "features"
4683 when choosing the configuration, i. e.
4686 - will configure for a plain TQM823L, i. e. no LCD support
4688 make TQM823L_LCD_config
4689 - will configure for a TQM823L with U-Boot console on LCD
4694 Finally, type "make all", and you should get some working U-Boot
4695 images ready for download to / installation on your system:
4697 - "u-boot.bin" is a raw binary image
4698 - "u-boot" is an image in ELF binary format
4699 - "u-boot.srec" is in Motorola S-Record format
4701 By default the build is performed locally and the objects are saved
4702 in the source directory. One of the two methods can be used to change
4703 this behavior and build U-Boot to some external directory:
4705 1. Add O= to the make command line invocations:
4707 make O=/tmp/build distclean
4708 make O=/tmp/build NAME_config
4709 make O=/tmp/build all
4711 2. Set environment variable BUILD_DIR to point to the desired location:
4713 export BUILD_DIR=/tmp/build
4718 Note that the command line "O=" setting overrides the BUILD_DIR environment
4722 Please be aware that the Makefiles assume you are using GNU make, so
4723 for instance on NetBSD you might need to use "gmake" instead of
4727 If the system board that you have is not listed, then you will need
4728 to port U-Boot to your hardware platform. To do this, follow these
4731 1. Add a new configuration option for your board to the toplevel
4732 "boards.cfg" file, using the existing entries as examples.
4733 Follow the instructions there to keep the boards in order.
4734 2. Create a new directory to hold your board specific code. Add any
4735 files you need. In your board directory, you will need at least
4736 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4737 3. Create a new configuration file "include/configs/<board>.h" for
4739 3. If you're porting U-Boot to a new CPU, then also create a new
4740 directory to hold your CPU specific code. Add any files you need.
4741 4. Run "make <board>_config" with your new name.
4742 5. Type "make", and you should get a working "u-boot.srec" file
4743 to be installed on your target system.
4744 6. Debug and solve any problems that might arise.
4745 [Of course, this last step is much harder than it sounds.]
4748 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4749 ==============================================================
4751 If you have modified U-Boot sources (for instance added a new board
4752 or support for new devices, a new CPU, etc.) you are expected to
4753 provide feedback to the other developers. The feedback normally takes
4754 the form of a "patch", i. e. a context diff against a certain (latest
4755 official or latest in the git repository) version of U-Boot sources.
4757 But before you submit such a patch, please verify that your modifi-
4758 cation did not break existing code. At least make sure that *ALL* of
4759 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4760 just run the "MAKEALL" script, which will configure and build U-Boot
4761 for ALL supported system. Be warned, this will take a while. You can
4762 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4763 environment variable to the script, i. e. to use the ELDK cross tools
4766 CROSS_COMPILE=ppc_8xx- MAKEALL
4768 or to build on a native PowerPC system you can type
4770 CROSS_COMPILE=' ' MAKEALL
4772 When using the MAKEALL script, the default behaviour is to build
4773 U-Boot in the source directory. This location can be changed by
4774 setting the BUILD_DIR environment variable. Also, for each target
4775 built, the MAKEALL script saves two log files (<target>.ERR and
4776 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4777 location can be changed by setting the MAKEALL_LOGDIR environment
4778 variable. For example:
4780 export BUILD_DIR=/tmp/build
4781 export MAKEALL_LOGDIR=/tmp/log
4782 CROSS_COMPILE=ppc_8xx- MAKEALL
4784 With the above settings build objects are saved in the /tmp/build,
4785 log files are saved in the /tmp/log and the source tree remains clean
4786 during the whole build process.
4789 See also "U-Boot Porting Guide" below.
4792 Monitor Commands - Overview:
4793 ============================
4795 go - start application at address 'addr'
4796 run - run commands in an environment variable
4797 bootm - boot application image from memory
4798 bootp - boot image via network using BootP/TFTP protocol
4799 bootz - boot zImage from memory
4800 tftpboot- boot image via network using TFTP protocol
4801 and env variables "ipaddr" and "serverip"
4802 (and eventually "gatewayip")
4803 tftpput - upload a file via network using TFTP protocol
4804 rarpboot- boot image via network using RARP/TFTP protocol
4805 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4806 loads - load S-Record file over serial line
4807 loadb - load binary file over serial line (kermit mode)
4809 mm - memory modify (auto-incrementing)
4810 nm - memory modify (constant address)
4811 mw - memory write (fill)
4813 cmp - memory compare
4814 crc32 - checksum calculation
4815 i2c - I2C sub-system
4816 sspi - SPI utility commands
4817 base - print or set address offset
4818 printenv- print environment variables
4819 setenv - set environment variables
4820 saveenv - save environment variables to persistent storage
4821 protect - enable or disable FLASH write protection
4822 erase - erase FLASH memory
4823 flinfo - print FLASH memory information
4824 nand - NAND memory operations (see doc/README.nand)
4825 bdinfo - print Board Info structure
4826 iminfo - print header information for application image
4827 coninfo - print console devices and informations
4828 ide - IDE sub-system
4829 loop - infinite loop on address range
4830 loopw - infinite write loop on address range
4831 mtest - simple RAM test
4832 icache - enable or disable instruction cache
4833 dcache - enable or disable data cache
4834 reset - Perform RESET of the CPU
4835 echo - echo args to console
4836 version - print monitor version
4837 help - print online help
4838 ? - alias for 'help'
4841 Monitor Commands - Detailed Description:
4842 ========================================
4846 For now: just type "help <command>".
4849 Environment Variables:
4850 ======================
4852 U-Boot supports user configuration using Environment Variables which
4853 can be made persistent by saving to Flash memory.
4855 Environment Variables are set using "setenv", printed using
4856 "printenv", and saved to Flash using "saveenv". Using "setenv"
4857 without a value can be used to delete a variable from the
4858 environment. As long as you don't save the environment you are
4859 working with an in-memory copy. In case the Flash area containing the
4860 environment is erased by accident, a default environment is provided.
4862 Some configuration options can be set using Environment Variables.
4864 List of environment variables (most likely not complete):
4866 baudrate - see CONFIG_BAUDRATE
4868 bootdelay - see CONFIG_BOOTDELAY
4870 bootcmd - see CONFIG_BOOTCOMMAND
4872 bootargs - Boot arguments when booting an RTOS image
4874 bootfile - Name of the image to load with TFTP
4876 bootm_low - Memory range available for image processing in the bootm
4877 command can be restricted. This variable is given as
4878 a hexadecimal number and defines lowest address allowed
4879 for use by the bootm command. See also "bootm_size"
4880 environment variable. Address defined by "bootm_low" is
4881 also the base of the initial memory mapping for the Linux
4882 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4885 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4886 This variable is given as a hexadecimal number and it
4887 defines the size of the memory region starting at base
4888 address bootm_low that is accessible by the Linux kernel
4889 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4890 as the default value if it is defined, and bootm_size is
4893 bootm_size - Memory range available for image processing in the bootm
4894 command can be restricted. This variable is given as
4895 a hexadecimal number and defines the size of the region
4896 allowed for use by the bootm command. See also "bootm_low"
4897 environment variable.
4899 updatefile - Location of the software update file on a TFTP server, used
4900 by the automatic software update feature. Please refer to
4901 documentation in doc/README.update for more details.
4903 autoload - if set to "no" (any string beginning with 'n'),
4904 "bootp" will just load perform a lookup of the
4905 configuration from the BOOTP server, but not try to
4906 load any image using TFTP
4908 autostart - if set to "yes", an image loaded using the "bootp",
4909 "rarpboot", "tftpboot" or "diskboot" commands will
4910 be automatically started (by internally calling
4913 If set to "no", a standalone image passed to the
4914 "bootm" command will be copied to the load address
4915 (and eventually uncompressed), but NOT be started.
4916 This can be used to load and uncompress arbitrary
4919 fdt_high - if set this restricts the maximum address that the
4920 flattened device tree will be copied into upon boot.
4921 For example, if you have a system with 1 GB memory
4922 at physical address 0x10000000, while Linux kernel
4923 only recognizes the first 704 MB as low memory, you
4924 may need to set fdt_high as 0x3C000000 to have the
4925 device tree blob be copied to the maximum address
4926 of the 704 MB low memory, so that Linux kernel can
4927 access it during the boot procedure.
4929 If this is set to the special value 0xFFFFFFFF then
4930 the fdt will not be copied at all on boot. For this
4931 to work it must reside in writable memory, have
4932 sufficient padding on the end of it for u-boot to
4933 add the information it needs into it, and the memory
4934 must be accessible by the kernel.
4936 fdtcontroladdr- if set this is the address of the control flattened
4937 device tree used by U-Boot when CONFIG_OF_CONTROL is
4940 i2cfast - (PPC405GP|PPC405EP only)
4941 if set to 'y' configures Linux I2C driver for fast
4942 mode (400kHZ). This environment variable is used in
4943 initialization code. So, for changes to be effective
4944 it must be saved and board must be reset.
4946 initrd_high - restrict positioning of initrd images:
4947 If this variable is not set, initrd images will be
4948 copied to the highest possible address in RAM; this
4949 is usually what you want since it allows for
4950 maximum initrd size. If for some reason you want to
4951 make sure that the initrd image is loaded below the
4952 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4953 variable to a value of "no" or "off" or "0".
4954 Alternatively, you can set it to a maximum upper
4955 address to use (U-Boot will still check that it
4956 does not overwrite the U-Boot stack and data).
4958 For instance, when you have a system with 16 MB
4959 RAM, and want to reserve 4 MB from use by Linux,
4960 you can do this by adding "mem=12M" to the value of
4961 the "bootargs" variable. However, now you must make
4962 sure that the initrd image is placed in the first
4963 12 MB as well - this can be done with
4965 setenv initrd_high 00c00000
4967 If you set initrd_high to 0xFFFFFFFF, this is an
4968 indication to U-Boot that all addresses are legal
4969 for the Linux kernel, including addresses in flash
4970 memory. In this case U-Boot will NOT COPY the
4971 ramdisk at all. This may be useful to reduce the
4972 boot time on your system, but requires that this
4973 feature is supported by your Linux kernel.
4975 ipaddr - IP address; needed for tftpboot command
4977 loadaddr - Default load address for commands like "bootp",
4978 "rarpboot", "tftpboot", "loadb" or "diskboot"
4980 loads_echo - see CONFIG_LOADS_ECHO
4982 serverip - TFTP server IP address; needed for tftpboot command
4984 bootretry - see CONFIG_BOOT_RETRY_TIME
4986 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4988 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4990 ethprime - controls which interface is used first.
4992 ethact - controls which interface is currently active.
4993 For example you can do the following
4995 => setenv ethact FEC
4996 => ping 192.168.0.1 # traffic sent on FEC
4997 => setenv ethact SCC
4998 => ping 10.0.0.1 # traffic sent on SCC
5000 ethrotate - When set to "no" U-Boot does not go through all
5001 available network interfaces.
5002 It just stays at the currently selected interface.
5004 netretry - When set to "no" each network operation will
5005 either succeed or fail without retrying.
5006 When set to "once" the network operation will
5007 fail when all the available network interfaces
5008 are tried once without success.
5009 Useful on scripts which control the retry operation
5012 npe_ucode - set load address for the NPE microcode
5014 silent_linux - If set then linux will be told to boot silently, by
5015 changing the console to be empty. If "yes" it will be
5016 made silent. If "no" it will not be made silent. If
5017 unset, then it will be made silent if the U-Boot console
5020 tftpsrcport - If this is set, the value is used for TFTP's
5023 tftpdstport - If this is set, the value is used for TFTP's UDP
5024 destination port instead of the Well Know Port 69.
5026 tftpblocksize - Block size to use for TFTP transfers; if not set,
5027 we use the TFTP server's default block size
5029 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5030 seconds, minimum value is 1000 = 1 second). Defines
5031 when a packet is considered to be lost so it has to
5032 be retransmitted. The default is 5000 = 5 seconds.
5033 Lowering this value may make downloads succeed
5034 faster in networks with high packet loss rates or
5035 with unreliable TFTP servers.
5037 vlan - When set to a value < 4095 the traffic over
5038 Ethernet is encapsulated/received over 802.1q
5041 The following image location variables contain the location of images
5042 used in booting. The "Image" column gives the role of the image and is
5043 not an environment variable name. The other columns are environment
5044 variable names. "File Name" gives the name of the file on a TFTP
5045 server, "RAM Address" gives the location in RAM the image will be
5046 loaded to, and "Flash Location" gives the image's address in NOR
5047 flash or offset in NAND flash.
5049 *Note* - these variables don't have to be defined for all boards, some
5050 boards currenlty use other variables for these purposes, and some
5051 boards use these variables for other purposes.
5053 Image File Name RAM Address Flash Location
5054 ----- --------- ----------- --------------
5055 u-boot u-boot u-boot_addr_r u-boot_addr
5056 Linux kernel bootfile kernel_addr_r kernel_addr
5057 device tree blob fdtfile fdt_addr_r fdt_addr
5058 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5060 The following environment variables may be used and automatically
5061 updated by the network boot commands ("bootp" and "rarpboot"),
5062 depending the information provided by your boot server:
5064 bootfile - see above
5065 dnsip - IP address of your Domain Name Server
5066 dnsip2 - IP address of your secondary Domain Name Server
5067 gatewayip - IP address of the Gateway (Router) to use
5068 hostname - Target hostname
5070 netmask - Subnet Mask
5071 rootpath - Pathname of the root filesystem on the NFS server
5072 serverip - see above
5075 There are two special Environment Variables:
5077 serial# - contains hardware identification information such
5078 as type string and/or serial number
5079 ethaddr - Ethernet address
5081 These variables can be set only once (usually during manufacturing of
5082 the board). U-Boot refuses to delete or overwrite these variables
5083 once they have been set once.
5086 Further special Environment Variables:
5088 ver - Contains the U-Boot version string as printed
5089 with the "version" command. This variable is
5090 readonly (see CONFIG_VERSION_VARIABLE).
5093 Please note that changes to some configuration parameters may take
5094 only effect after the next boot (yes, that's just like Windoze :-).
5097 Callback functions for environment variables:
5098 ---------------------------------------------
5100 For some environment variables, the behavior of u-boot needs to change
5101 when their values are changed. This functionailty allows functions to
5102 be associated with arbitrary variables. On creation, overwrite, or
5103 deletion, the callback will provide the opportunity for some side
5104 effect to happen or for the change to be rejected.
5106 The callbacks are named and associated with a function using the
5107 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5109 These callbacks are associated with variables in one of two ways. The
5110 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5111 in the board configuration to a string that defines a list of
5112 associations. The list must be in the following format:
5114 entry = variable_name[:callback_name]
5117 If the callback name is not specified, then the callback is deleted.
5118 Spaces are also allowed anywhere in the list.
5120 Callbacks can also be associated by defining the ".callbacks" variable
5121 with the same list format above. Any association in ".callbacks" will
5122 override any association in the static list. You can define
5123 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5124 ".callbacks" envirnoment variable in the default or embedded environment.
5127 Command Line Parsing:
5128 =====================
5130 There are two different command line parsers available with U-Boot:
5131 the old "simple" one, and the much more powerful "hush" shell:
5133 Old, simple command line parser:
5134 --------------------------------
5136 - supports environment variables (through setenv / saveenv commands)
5137 - several commands on one line, separated by ';'
5138 - variable substitution using "... ${name} ..." syntax
5139 - special characters ('$', ';') can be escaped by prefixing with '\',
5141 setenv bootcmd bootm \${address}
5142 - You can also escape text by enclosing in single apostrophes, for example:
5143 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5148 - similar to Bourne shell, with control structures like
5149 if...then...else...fi, for...do...done; while...do...done,
5150 until...do...done, ...
5151 - supports environment ("global") variables (through setenv / saveenv
5152 commands) and local shell variables (through standard shell syntax
5153 "name=value"); only environment variables can be used with "run"
5159 (1) If a command line (or an environment variable executed by a "run"
5160 command) contains several commands separated by semicolon, and
5161 one of these commands fails, then the remaining commands will be
5164 (2) If you execute several variables with one call to run (i. e.
5165 calling run with a list of variables as arguments), any failing
5166 command will cause "run" to terminate, i. e. the remaining
5167 variables are not executed.
5169 Note for Redundant Ethernet Interfaces:
5170 =======================================
5172 Some boards come with redundant Ethernet interfaces; U-Boot supports
5173 such configurations and is capable of automatic selection of a
5174 "working" interface when needed. MAC assignment works as follows:
5176 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5177 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5178 "eth1addr" (=>eth1), "eth2addr", ...
5180 If the network interface stores some valid MAC address (for instance
5181 in SROM), this is used as default address if there is NO correspon-
5182 ding setting in the environment; if the corresponding environment
5183 variable is set, this overrides the settings in the card; that means:
5185 o If the SROM has a valid MAC address, and there is no address in the
5186 environment, the SROM's address is used.
5188 o If there is no valid address in the SROM, and a definition in the
5189 environment exists, then the value from the environment variable is
5192 o If both the SROM and the environment contain a MAC address, and
5193 both addresses are the same, this MAC address is used.
5195 o If both the SROM and the environment contain a MAC address, and the
5196 addresses differ, the value from the environment is used and a
5199 o If neither SROM nor the environment contain a MAC address, an error
5202 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5203 will be programmed into hardware as part of the initialization process. This
5204 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5205 The naming convention is as follows:
5206 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5211 U-Boot is capable of booting (and performing other auxiliary operations on)
5212 images in two formats:
5214 New uImage format (FIT)
5215 -----------------------
5217 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5218 to Flattened Device Tree). It allows the use of images with multiple
5219 components (several kernels, ramdisks, etc.), with contents protected by
5220 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5226 Old image format is based on binary files which can be basically anything,
5227 preceded by a special header; see the definitions in include/image.h for
5228 details; basically, the header defines the following image properties:
5230 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5231 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5232 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5233 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5235 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5236 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5237 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5238 * Compression Type (uncompressed, gzip, bzip2)
5244 The header is marked by a special Magic Number, and both the header
5245 and the data portions of the image are secured against corruption by
5252 Although U-Boot should support any OS or standalone application
5253 easily, the main focus has always been on Linux during the design of
5256 U-Boot includes many features that so far have been part of some
5257 special "boot loader" code within the Linux kernel. Also, any
5258 "initrd" images to be used are no longer part of one big Linux image;
5259 instead, kernel and "initrd" are separate images. This implementation
5260 serves several purposes:
5262 - the same features can be used for other OS or standalone
5263 applications (for instance: using compressed images to reduce the
5264 Flash memory footprint)
5266 - it becomes much easier to port new Linux kernel versions because
5267 lots of low-level, hardware dependent stuff are done by U-Boot
5269 - the same Linux kernel image can now be used with different "initrd"
5270 images; of course this also means that different kernel images can
5271 be run with the same "initrd". This makes testing easier (you don't
5272 have to build a new "zImage.initrd" Linux image when you just
5273 change a file in your "initrd"). Also, a field-upgrade of the
5274 software is easier now.
5280 Porting Linux to U-Boot based systems:
5281 ---------------------------------------
5283 U-Boot cannot save you from doing all the necessary modifications to
5284 configure the Linux device drivers for use with your target hardware
5285 (no, we don't intend to provide a full virtual machine interface to
5288 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5290 Just make sure your machine specific header file (for instance
5291 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5292 Information structure as we define in include/asm-<arch>/u-boot.h,
5293 and make sure that your definition of IMAP_ADDR uses the same value
5294 as your U-Boot configuration in CONFIG_SYS_IMMR.
5297 Configuring the Linux kernel:
5298 -----------------------------
5300 No specific requirements for U-Boot. Make sure you have some root
5301 device (initial ramdisk, NFS) for your target system.
5304 Building a Linux Image:
5305 -----------------------
5307 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5308 not used. If you use recent kernel source, a new build target
5309 "uImage" will exist which automatically builds an image usable by
5310 U-Boot. Most older kernels also have support for a "pImage" target,
5311 which was introduced for our predecessor project PPCBoot and uses a
5312 100% compatible format.
5321 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5322 encapsulate a compressed Linux kernel image with header information,
5323 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5325 * build a standard "vmlinux" kernel image (in ELF binary format):
5327 * convert the kernel into a raw binary image:
5329 ${CROSS_COMPILE}-objcopy -O binary \
5330 -R .note -R .comment \
5331 -S vmlinux linux.bin
5333 * compress the binary image:
5337 * package compressed binary image for U-Boot:
5339 mkimage -A ppc -O linux -T kernel -C gzip \
5340 -a 0 -e 0 -n "Linux Kernel Image" \
5341 -d linux.bin.gz uImage
5344 The "mkimage" tool can also be used to create ramdisk images for use
5345 with U-Boot, either separated from the Linux kernel image, or
5346 combined into one file. "mkimage" encapsulates the images with a 64
5347 byte header containing information about target architecture,
5348 operating system, image type, compression method, entry points, time
5349 stamp, CRC32 checksums, etc.
5351 "mkimage" can be called in two ways: to verify existing images and
5352 print the header information, or to build new images.
5354 In the first form (with "-l" option) mkimage lists the information
5355 contained in the header of an existing U-Boot image; this includes
5356 checksum verification:
5358 tools/mkimage -l image
5359 -l ==> list image header information
5361 The second form (with "-d" option) is used to build a U-Boot image
5362 from a "data file" which is used as image payload:
5364 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5365 -n name -d data_file image
5366 -A ==> set architecture to 'arch'
5367 -O ==> set operating system to 'os'
5368 -T ==> set image type to 'type'
5369 -C ==> set compression type 'comp'
5370 -a ==> set load address to 'addr' (hex)
5371 -e ==> set entry point to 'ep' (hex)
5372 -n ==> set image name to 'name'
5373 -d ==> use image data from 'datafile'
5375 Right now, all Linux kernels for PowerPC systems use the same load
5376 address (0x00000000), but the entry point address depends on the
5379 - 2.2.x kernels have the entry point at 0x0000000C,
5380 - 2.3.x and later kernels have the entry point at 0x00000000.
5382 So a typical call to build a U-Boot image would read:
5384 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5385 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5386 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5387 > examples/uImage.TQM850L
5388 Image Name: 2.4.4 kernel for TQM850L
5389 Created: Wed Jul 19 02:34:59 2000
5390 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5391 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5392 Load Address: 0x00000000
5393 Entry Point: 0x00000000
5395 To verify the contents of the image (or check for corruption):
5397 -> tools/mkimage -l examples/uImage.TQM850L
5398 Image Name: 2.4.4 kernel for TQM850L
5399 Created: Wed Jul 19 02:34:59 2000
5400 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5401 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5402 Load Address: 0x00000000
5403 Entry Point: 0x00000000
5405 NOTE: for embedded systems where boot time is critical you can trade
5406 speed for memory and install an UNCOMPRESSED image instead: this
5407 needs more space in Flash, but boots much faster since it does not
5408 need to be uncompressed:
5410 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5411 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5412 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5413 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5414 > examples/uImage.TQM850L-uncompressed
5415 Image Name: 2.4.4 kernel for TQM850L
5416 Created: Wed Jul 19 02:34:59 2000
5417 Image Type: PowerPC Linux Kernel Image (uncompressed)
5418 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5419 Load Address: 0x00000000
5420 Entry Point: 0x00000000
5423 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5424 when your kernel is intended to use an initial ramdisk:
5426 -> tools/mkimage -n 'Simple Ramdisk Image' \
5427 > -A ppc -O linux -T ramdisk -C gzip \
5428 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5429 Image Name: Simple Ramdisk Image
5430 Created: Wed Jan 12 14:01:50 2000
5431 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5432 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5433 Load Address: 0x00000000
5434 Entry Point: 0x00000000
5436 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5437 option performs the converse operation of the mkimage's second form (the "-d"
5438 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5441 tools/dumpimage -i image -p position data_file
5442 -i ==> extract from the 'image' a specific 'data_file', \
5443 indexed by 'position'
5446 Installing a Linux Image:
5447 -------------------------
5449 To downloading a U-Boot image over the serial (console) interface,
5450 you must convert the image to S-Record format:
5452 objcopy -I binary -O srec examples/image examples/image.srec
5454 The 'objcopy' does not understand the information in the U-Boot
5455 image header, so the resulting S-Record file will be relative to
5456 address 0x00000000. To load it to a given address, you need to
5457 specify the target address as 'offset' parameter with the 'loads'
5460 Example: install the image to address 0x40100000 (which on the
5461 TQM8xxL is in the first Flash bank):
5463 => erase 40100000 401FFFFF
5469 ## Ready for S-Record download ...
5470 ~>examples/image.srec
5471 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5473 15989 15990 15991 15992
5474 [file transfer complete]
5476 ## Start Addr = 0x00000000
5479 You can check the success of the download using the 'iminfo' command;
5480 this includes a checksum verification so you can be sure no data
5481 corruption happened:
5485 ## Checking Image at 40100000 ...
5486 Image Name: 2.2.13 for initrd on TQM850L
5487 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5488 Data Size: 335725 Bytes = 327 kB = 0 MB
5489 Load Address: 00000000
5490 Entry Point: 0000000c
5491 Verifying Checksum ... OK
5497 The "bootm" command is used to boot an application that is stored in
5498 memory (RAM or Flash). In case of a Linux kernel image, the contents
5499 of the "bootargs" environment variable is passed to the kernel as
5500 parameters. You can check and modify this variable using the
5501 "printenv" and "setenv" commands:
5504 => printenv bootargs
5505 bootargs=root=/dev/ram
5507 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5509 => printenv bootargs
5510 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5513 ## Booting Linux kernel at 40020000 ...
5514 Image Name: 2.2.13 for NFS on TQM850L
5515 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5516 Data Size: 381681 Bytes = 372 kB = 0 MB
5517 Load Address: 00000000
5518 Entry Point: 0000000c
5519 Verifying Checksum ... OK
5520 Uncompressing Kernel Image ... OK
5521 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
5522 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5523 time_init: decrementer frequency = 187500000/60
5524 Calibrating delay loop... 49.77 BogoMIPS
5525 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5528 If you want to boot a Linux kernel with initial RAM disk, you pass
5529 the memory addresses of both the kernel and the initrd image (PPBCOOT
5530 format!) to the "bootm" command:
5532 => imi 40100000 40200000
5534 ## Checking Image at 40100000 ...
5535 Image Name: 2.2.13 for initrd on TQM850L
5536 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5537 Data Size: 335725 Bytes = 327 kB = 0 MB
5538 Load Address: 00000000
5539 Entry Point: 0000000c
5540 Verifying Checksum ... OK
5542 ## Checking Image at 40200000 ...
5543 Image Name: Simple Ramdisk Image
5544 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5545 Data Size: 566530 Bytes = 553 kB = 0 MB
5546 Load Address: 00000000
5547 Entry Point: 00000000
5548 Verifying Checksum ... OK
5550 => bootm 40100000 40200000
5551 ## Booting Linux kernel at 40100000 ...
5552 Image Name: 2.2.13 for initrd on TQM850L
5553 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5554 Data Size: 335725 Bytes = 327 kB = 0 MB
5555 Load Address: 00000000
5556 Entry Point: 0000000c
5557 Verifying Checksum ... OK
5558 Uncompressing Kernel Image ... OK
5559 ## Loading RAMDisk Image at 40200000 ...
5560 Image Name: Simple Ramdisk Image
5561 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5562 Data Size: 566530 Bytes = 553 kB = 0 MB
5563 Load Address: 00000000
5564 Entry Point: 00000000
5565 Verifying Checksum ... OK
5566 Loading Ramdisk ... OK
5567 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
5568 Boot arguments: root=/dev/ram
5569 time_init: decrementer frequency = 187500000/60
5570 Calibrating delay loop... 49.77 BogoMIPS
5572 RAMDISK: Compressed image found at block 0
5573 VFS: Mounted root (ext2 filesystem).
5577 Boot Linux and pass a flat device tree:
5580 First, U-Boot must be compiled with the appropriate defines. See the section
5581 titled "Linux Kernel Interface" above for a more in depth explanation. The
5582 following is an example of how to start a kernel and pass an updated
5588 oft=oftrees/mpc8540ads.dtb
5589 => tftp $oftaddr $oft
5590 Speed: 1000, full duplex
5592 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5593 Filename 'oftrees/mpc8540ads.dtb'.
5594 Load address: 0x300000
5597 Bytes transferred = 4106 (100a hex)
5598 => tftp $loadaddr $bootfile
5599 Speed: 1000, full duplex
5601 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5603 Load address: 0x200000
5604 Loading:############
5606 Bytes transferred = 1029407 (fb51f hex)
5611 => bootm $loadaddr - $oftaddr
5612 ## Booting image at 00200000 ...
5613 Image Name: Linux-2.6.17-dirty
5614 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5615 Data Size: 1029343 Bytes = 1005.2 kB
5616 Load Address: 00000000
5617 Entry Point: 00000000
5618 Verifying Checksum ... OK
5619 Uncompressing Kernel Image ... OK
5620 Booting using flat device tree at 0x300000
5621 Using MPC85xx ADS machine description
5622 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5626 More About U-Boot Image Types:
5627 ------------------------------
5629 U-Boot supports the following image types:
5631 "Standalone Programs" are directly runnable in the environment
5632 provided by U-Boot; it is expected that (if they behave
5633 well) you can continue to work in U-Boot after return from
5634 the Standalone Program.
5635 "OS Kernel Images" are usually images of some Embedded OS which
5636 will take over control completely. Usually these programs
5637 will install their own set of exception handlers, device
5638 drivers, set up the MMU, etc. - this means, that you cannot
5639 expect to re-enter U-Boot except by resetting the CPU.
5640 "RAMDisk Images" are more or less just data blocks, and their
5641 parameters (address, size) are passed to an OS kernel that is
5643 "Multi-File Images" contain several images, typically an OS
5644 (Linux) kernel image and one or more data images like
5645 RAMDisks. This construct is useful for instance when you want
5646 to boot over the network using BOOTP etc., where the boot
5647 server provides just a single image file, but you want to get
5648 for instance an OS kernel and a RAMDisk image.
5650 "Multi-File Images" start with a list of image sizes, each
5651 image size (in bytes) specified by an "uint32_t" in network
5652 byte order. This list is terminated by an "(uint32_t)0".
5653 Immediately after the terminating 0 follow the images, one by
5654 one, all aligned on "uint32_t" boundaries (size rounded up to
5655 a multiple of 4 bytes).
5657 "Firmware Images" are binary images containing firmware (like
5658 U-Boot or FPGA images) which usually will be programmed to
5661 "Script files" are command sequences that will be executed by
5662 U-Boot's command interpreter; this feature is especially
5663 useful when you configure U-Boot to use a real shell (hush)
5664 as command interpreter.
5666 Booting the Linux zImage:
5667 -------------------------
5669 On some platforms, it's possible to boot Linux zImage. This is done
5670 using the "bootz" command. The syntax of "bootz" command is the same
5671 as the syntax of "bootm" command.
5673 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5674 kernel with raw initrd images. The syntax is slightly different, the
5675 address of the initrd must be augmented by it's size, in the following
5676 format: "<initrd addres>:<initrd size>".
5682 One of the features of U-Boot is that you can dynamically load and
5683 run "standalone" applications, which can use some resources of
5684 U-Boot like console I/O functions or interrupt services.
5686 Two simple examples are included with the sources:
5691 'examples/hello_world.c' contains a small "Hello World" Demo
5692 application; it is automatically compiled when you build U-Boot.
5693 It's configured to run at address 0x00040004, so you can play with it
5697 ## Ready for S-Record download ...
5698 ~>examples/hello_world.srec
5699 1 2 3 4 5 6 7 8 9 10 11 ...
5700 [file transfer complete]
5702 ## Start Addr = 0x00040004
5704 => go 40004 Hello World! This is a test.
5705 ## Starting application at 0x00040004 ...
5716 Hit any key to exit ...
5718 ## Application terminated, rc = 0x0
5720 Another example, which demonstrates how to register a CPM interrupt
5721 handler with the U-Boot code, can be found in 'examples/timer.c'.
5722 Here, a CPM timer is set up to generate an interrupt every second.
5723 The interrupt service routine is trivial, just printing a '.'
5724 character, but this is just a demo program. The application can be
5725 controlled by the following keys:
5727 ? - print current values og the CPM Timer registers
5728 b - enable interrupts and start timer
5729 e - stop timer and disable interrupts
5730 q - quit application
5733 ## Ready for S-Record download ...
5734 ~>examples/timer.srec
5735 1 2 3 4 5 6 7 8 9 10 11 ...
5736 [file transfer complete]
5738 ## Start Addr = 0x00040004
5741 ## Starting application at 0x00040004 ...
5744 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5747 [q, b, e, ?] Set interval 1000000 us
5750 [q, b, e, ?] ........
5751 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5754 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5757 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5760 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5762 [q, b, e, ?] ...Stopping timer
5764 [q, b, e, ?] ## Application terminated, rc = 0x0
5770 Over time, many people have reported problems when trying to use the
5771 "minicom" terminal emulation program for serial download. I (wd)
5772 consider minicom to be broken, and recommend not to use it. Under
5773 Unix, I recommend to use C-Kermit for general purpose use (and
5774 especially for kermit binary protocol download ("loadb" command), and
5775 use "cu" for S-Record download ("loads" command). See
5776 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5777 for help with kermit.
5780 Nevertheless, if you absolutely want to use it try adding this
5781 configuration to your "File transfer protocols" section:
5783 Name Program Name U/D FullScr IO-Red. Multi
5784 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5785 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5791 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5792 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5794 Building requires a cross environment; it is known to work on
5795 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5796 need gmake since the Makefiles are not compatible with BSD make).
5797 Note that the cross-powerpc package does not install include files;
5798 attempting to build U-Boot will fail because <machine/ansi.h> is
5799 missing. This file has to be installed and patched manually:
5801 # cd /usr/pkg/cross/powerpc-netbsd/include
5803 # ln -s powerpc machine
5804 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5805 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5807 Native builds *don't* work due to incompatibilities between native
5808 and U-Boot include files.
5810 Booting assumes that (the first part of) the image booted is a
5811 stage-2 loader which in turn loads and then invokes the kernel
5812 proper. Loader sources will eventually appear in the NetBSD source
5813 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5814 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5817 Implementation Internals:
5818 =========================
5820 The following is not intended to be a complete description of every
5821 implementation detail. However, it should help to understand the
5822 inner workings of U-Boot and make it easier to port it to custom
5826 Initial Stack, Global Data:
5827 ---------------------------
5829 The implementation of U-Boot is complicated by the fact that U-Boot
5830 starts running out of ROM (flash memory), usually without access to
5831 system RAM (because the memory controller is not initialized yet).
5832 This means that we don't have writable Data or BSS segments, and BSS
5833 is not initialized as zero. To be able to get a C environment working
5834 at all, we have to allocate at least a minimal stack. Implementation
5835 options for this are defined and restricted by the CPU used: Some CPU
5836 models provide on-chip memory (like the IMMR area on MPC8xx and
5837 MPC826x processors), on others (parts of) the data cache can be
5838 locked as (mis-) used as memory, etc.
5840 Chris Hallinan posted a good summary of these issues to the
5841 U-Boot mailing list:
5843 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5844 From: "Chris Hallinan" <clh@net1plus.com>
5845 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5848 Correct me if I'm wrong, folks, but the way I understand it
5849 is this: Using DCACHE as initial RAM for Stack, etc, does not
5850 require any physical RAM backing up the cache. The cleverness
5851 is that the cache is being used as a temporary supply of
5852 necessary storage before the SDRAM controller is setup. It's
5853 beyond the scope of this list to explain the details, but you
5854 can see how this works by studying the cache architecture and
5855 operation in the architecture and processor-specific manuals.
5857 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5858 is another option for the system designer to use as an
5859 initial stack/RAM area prior to SDRAM being available. Either
5860 option should work for you. Using CS 4 should be fine if your
5861 board designers haven't used it for something that would
5862 cause you grief during the initial boot! It is frequently not
5865 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5866 with your processor/board/system design. The default value
5867 you will find in any recent u-boot distribution in
5868 walnut.h should work for you. I'd set it to a value larger
5869 than your SDRAM module. If you have a 64MB SDRAM module, set
5870 it above 400_0000. Just make sure your board has no resources
5871 that are supposed to respond to that address! That code in
5872 start.S has been around a while and should work as is when
5873 you get the config right.
5878 It is essential to remember this, since it has some impact on the C
5879 code for the initialization procedures:
5881 * Initialized global data (data segment) is read-only. Do not attempt
5884 * Do not use any uninitialized global data (or implicitely initialized
5885 as zero data - BSS segment) at all - this is undefined, initiali-
5886 zation is performed later (when relocating to RAM).
5888 * Stack space is very limited. Avoid big data buffers or things like
5891 Having only the stack as writable memory limits means we cannot use
5892 normal global data to share information beween the code. But it
5893 turned out that the implementation of U-Boot can be greatly
5894 simplified by making a global data structure (gd_t) available to all
5895 functions. We could pass a pointer to this data as argument to _all_
5896 functions, but this would bloat the code. Instead we use a feature of
5897 the GCC compiler (Global Register Variables) to share the data: we
5898 place a pointer (gd) to the global data into a register which we
5899 reserve for this purpose.
5901 When choosing a register for such a purpose we are restricted by the
5902 relevant (E)ABI specifications for the current architecture, and by
5903 GCC's implementation.
5905 For PowerPC, the following registers have specific use:
5907 R2: reserved for system use
5908 R3-R4: parameter passing and return values
5909 R5-R10: parameter passing
5910 R13: small data area pointer
5914 (U-Boot also uses R12 as internal GOT pointer. r12
5915 is a volatile register so r12 needs to be reset when
5916 going back and forth between asm and C)
5918 ==> U-Boot will use R2 to hold a pointer to the global data
5920 Note: on PPC, we could use a static initializer (since the
5921 address of the global data structure is known at compile time),
5922 but it turned out that reserving a register results in somewhat
5923 smaller code - although the code savings are not that big (on
5924 average for all boards 752 bytes for the whole U-Boot image,
5925 624 text + 127 data).
5927 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5928 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5930 ==> U-Boot will use P3 to hold a pointer to the global data
5932 On ARM, the following registers are used:
5934 R0: function argument word/integer result
5935 R1-R3: function argument word
5936 R9: platform specific
5937 R10: stack limit (used only if stack checking is enabled)
5938 R11: argument (frame) pointer
5939 R12: temporary workspace
5942 R15: program counter
5944 ==> U-Boot will use R9 to hold a pointer to the global data
5946 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5948 On Nios II, the ABI is documented here:
5949 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5951 ==> U-Boot will use gp to hold a pointer to the global data
5953 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5954 to access small data sections, so gp is free.
5956 On NDS32, the following registers are used:
5958 R0-R1: argument/return
5960 R15: temporary register for assembler
5961 R16: trampoline register
5962 R28: frame pointer (FP)
5963 R29: global pointer (GP)
5964 R30: link register (LP)
5965 R31: stack pointer (SP)
5966 PC: program counter (PC)
5968 ==> U-Boot will use R10 to hold a pointer to the global data
5970 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5971 or current versions of GCC may "optimize" the code too much.
5976 U-Boot runs in system state and uses physical addresses, i.e. the
5977 MMU is not used either for address mapping nor for memory protection.
5979 The available memory is mapped to fixed addresses using the memory
5980 controller. In this process, a contiguous block is formed for each
5981 memory type (Flash, SDRAM, SRAM), even when it consists of several
5982 physical memory banks.
5984 U-Boot is installed in the first 128 kB of the first Flash bank (on
5985 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5986 booting and sizing and initializing DRAM, the code relocates itself
5987 to the upper end of DRAM. Immediately below the U-Boot code some
5988 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5989 configuration setting]. Below that, a structure with global Board
5990 Info data is placed, followed by the stack (growing downward).
5992 Additionally, some exception handler code is copied to the low 8 kB
5993 of DRAM (0x00000000 ... 0x00001FFF).
5995 So a typical memory configuration with 16 MB of DRAM could look like
5998 0x0000 0000 Exception Vector code
6001 0x0000 2000 Free for Application Use
6007 0x00FB FF20 Monitor Stack (Growing downward)
6008 0x00FB FFAC Board Info Data and permanent copy of global data
6009 0x00FC 0000 Malloc Arena
6012 0x00FE 0000 RAM Copy of Monitor Code
6013 ... eventually: LCD or video framebuffer
6014 ... eventually: pRAM (Protected RAM - unchanged by reset)
6015 0x00FF FFFF [End of RAM]
6018 System Initialization:
6019 ----------------------
6021 In the reset configuration, U-Boot starts at the reset entry point
6022 (on most PowerPC systems at address 0x00000100). Because of the reset
6023 configuration for CS0# this is a mirror of the onboard Flash memory.
6024 To be able to re-map memory U-Boot then jumps to its link address.
6025 To be able to implement the initialization code in C, a (small!)
6026 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6027 which provide such a feature like MPC8xx or MPC8260), or in a locked
6028 part of the data cache. After that, U-Boot initializes the CPU core,
6029 the caches and the SIU.
6031 Next, all (potentially) available memory banks are mapped using a
6032 preliminary mapping. For example, we put them on 512 MB boundaries
6033 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6034 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6035 programmed for SDRAM access. Using the temporary configuration, a
6036 simple memory test is run that determines the size of the SDRAM
6039 When there is more than one SDRAM bank, and the banks are of
6040 different size, the largest is mapped first. For equal size, the first
6041 bank (CS2#) is mapped first. The first mapping is always for address
6042 0x00000000, with any additional banks following immediately to create
6043 contiguous memory starting from 0.
6045 Then, the monitor installs itself at the upper end of the SDRAM area
6046 and allocates memory for use by malloc() and for the global Board
6047 Info data; also, the exception vector code is copied to the low RAM
6048 pages, and the final stack is set up.
6050 Only after this relocation will you have a "normal" C environment;
6051 until that you are restricted in several ways, mostly because you are
6052 running from ROM, and because the code will have to be relocated to a
6056 U-Boot Porting Guide:
6057 ----------------------
6059 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6063 int main(int argc, char *argv[])
6065 sighandler_t no_more_time;
6067 signal(SIGALRM, no_more_time);
6068 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6070 if (available_money > available_manpower) {
6071 Pay consultant to port U-Boot;
6075 Download latest U-Boot source;
6077 Subscribe to u-boot mailing list;
6080 email("Hi, I am new to U-Boot, how do I get started?");
6083 Read the README file in the top level directory;
6084 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6085 Read applicable doc/*.README;
6086 Read the source, Luke;
6087 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6090 if (available_money > toLocalCurrency ($2500))
6093 Add a lot of aggravation and time;
6095 if (a similar board exists) { /* hopefully... */
6096 cp -a board/<similar> board/<myboard>
6097 cp include/configs/<similar>.h include/configs/<myboard>.h
6099 Create your own board support subdirectory;
6100 Create your own board include/configs/<myboard>.h file;
6102 Edit new board/<myboard> files
6103 Edit new include/configs/<myboard>.h
6108 Add / modify source code;
6112 email("Hi, I am having problems...");
6114 Send patch file to the U-Boot email list;
6115 if (reasonable critiques)
6116 Incorporate improvements from email list code review;
6118 Defend code as written;
6124 void no_more_time (int sig)
6133 All contributions to U-Boot should conform to the Linux kernel
6134 coding style; see the file "Documentation/CodingStyle" and the script
6135 "scripts/Lindent" in your Linux kernel source directory.
6137 Source files originating from a different project (for example the
6138 MTD subsystem) are generally exempt from these guidelines and are not
6139 reformated to ease subsequent migration to newer versions of those
6142 Please note that U-Boot is implemented in C (and to some small parts in
6143 Assembler); no C++ is used, so please do not use C++ style comments (//)
6146 Please also stick to the following formatting rules:
6147 - remove any trailing white space
6148 - use TAB characters for indentation and vertical alignment, not spaces
6149 - make sure NOT to use DOS '\r\n' line feeds
6150 - do not add more than 2 consecutive empty lines to source files
6151 - do not add trailing empty lines to source files
6153 Submissions which do not conform to the standards may be returned
6154 with a request to reformat the changes.
6160 Since the number of patches for U-Boot is growing, we need to
6161 establish some rules. Submissions which do not conform to these rules
6162 may be rejected, even when they contain important and valuable stuff.
6164 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6166 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6167 see http://lists.denx.de/mailman/listinfo/u-boot
6169 When you send a patch, please include the following information with
6172 * For bug fixes: a description of the bug and how your patch fixes
6173 this bug. Please try to include a way of demonstrating that the
6174 patch actually fixes something.
6176 * For new features: a description of the feature and your
6179 * A CHANGELOG entry as plaintext (separate from the patch)
6181 * For major contributions, your entry to the CREDITS file
6183 * When you add support for a new board, don't forget to add a
6184 maintainer e-mail address to the boards.cfg file, too.
6186 * If your patch adds new configuration options, don't forget to
6187 document these in the README file.
6189 * The patch itself. If you are using git (which is *strongly*
6190 recommended) you can easily generate the patch using the
6191 "git format-patch". If you then use "git send-email" to send it to
6192 the U-Boot mailing list, you will avoid most of the common problems
6193 with some other mail clients.
6195 If you cannot use git, use "diff -purN OLD NEW". If your version of
6196 diff does not support these options, then get the latest version of
6199 The current directory when running this command shall be the parent
6200 directory of the U-Boot source tree (i. e. please make sure that
6201 your patch includes sufficient directory information for the
6204 We prefer patches as plain text. MIME attachments are discouraged,
6205 and compressed attachments must not be used.
6207 * If one logical set of modifications affects or creates several
6208 files, all these changes shall be submitted in a SINGLE patch file.
6210 * Changesets that contain different, unrelated modifications shall be
6211 submitted as SEPARATE patches, one patch per changeset.
6216 * Before sending the patch, run the MAKEALL script on your patched
6217 source tree and make sure that no errors or warnings are reported
6218 for any of the boards.
6220 * Keep your modifications to the necessary minimum: A patch
6221 containing several unrelated changes or arbitrary reformats will be
6222 returned with a request to re-formatting / split it.
6224 * If you modify existing code, make sure that your new code does not
6225 add to the memory footprint of the code ;-) Small is beautiful!
6226 When adding new features, these should compile conditionally only
6227 (using #ifdef), and the resulting code with the new feature
6228 disabled must not need more memory than the old code without your
6231 * Remember that there is a size limit of 100 kB per message on the
6232 u-boot mailing list. Bigger patches will be moderated. If they are
6233 reasonable and not too big, they will be acknowledged. But patches
6234 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob