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 /mpc5xx Files specific to Freescale MPC5xx CPUs
186 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
187 /mpc8xx Files specific to Freescale MPC8xx CPUs
188 /mpc8260 Files specific to Freescale MPC8260 CPUs
189 /mpc85xx Files specific to Freescale MPC85xx CPUs
190 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
191 /lib Architecture specific library files
192 /sh Files generic to SH architecture
193 /cpu CPU specific files
194 /sh2 Files specific to sh2 CPUs
195 /sh3 Files specific to sh3 CPUs
196 /sh4 Files specific to sh4 CPUs
197 /lib Architecture specific library files
198 /sparc Files generic to SPARC architecture
199 /cpu CPU specific files
200 /leon2 Files specific to Gaisler LEON2 SPARC CPU
201 /leon3 Files specific to Gaisler LEON3 SPARC CPU
202 /lib Architecture specific library files
203 /x86 Files generic to x86 architecture
204 /cpu CPU specific files
205 /lib Architecture specific library files
206 /api Machine/arch independent API for external apps
207 /board Board dependent files
208 /common Misc architecture independent functions
209 /disk Code for disk drive partition handling
210 /doc Documentation (don't expect too much)
211 /drivers Commonly used device drivers
212 /dts Contains Makefile for building internal U-Boot fdt.
213 /examples Example code for standalone applications, etc.
214 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
215 /include Header Files
216 /lib Files generic to all architectures
217 /libfdt Library files to support flattened device trees
218 /lzma Library files to support LZMA decompression
219 /lzo Library files to support LZO decompression
221 /post Power On Self Test
222 /spl Secondary Program Loader framework
223 /tools Tools to build S-Record or U-Boot images, etc.
225 Software Configuration:
226 =======================
228 Configuration is usually done using C preprocessor defines; the
229 rationale behind that is to avoid dead code whenever possible.
231 There are two classes of configuration variables:
233 * Configuration _OPTIONS_:
234 These are selectable by the user and have names beginning with
237 * Configuration _SETTINGS_:
238 These depend on the hardware etc. and should not be meddled with if
239 you don't know what you're doing; they have names beginning with
242 Later we will add a configuration tool - probably similar to or even
243 identical to what's used for the Linux kernel. Right now, we have to
244 do the configuration by hand, which means creating some symbolic
245 links and editing some configuration files. We use the TQM8xxL boards
249 Selection of Processor Architecture and Board Type:
250 ---------------------------------------------------
252 For all supported boards there are ready-to-use default
253 configurations available; just type "make <board_name>_defconfig".
255 Example: For a TQM823L module type:
258 make TQM823L_defconfig
260 For the Cogent platform, you need to specify the CPU type as well;
261 e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
262 directory according to the instructions in cogent/README.
268 U-Boot can be built natively to run on a Linux host using the 'sandbox'
269 board. This allows feature development which is not board- or architecture-
270 specific to be undertaken on a native platform. The sandbox is also used to
271 run some of U-Boot's tests.
273 See board/sandbox/README.sandbox for more details.
276 Board Initialisation Flow:
277 --------------------------
279 This is the intended start-up flow for boards. This should apply for both
280 SPL and U-Boot proper (i.e. they both follow the same rules). At present SPL
281 mostly uses a separate code path, but the funtion names and roles of each
282 function are the same. Some boards or architectures may not conform to this.
283 At least most ARM boards which use CONFIG_SPL_FRAMEWORK conform to this.
285 Execution starts with start.S with three functions called during init after
286 that. The purpose and limitations of each is described below.
289 - purpose: essential init to permit execution to reach board_init_f()
290 - no global_data or BSS
291 - there is no stack (ARMv7 may have one but it will soon be removed)
292 - must not set up SDRAM or use console
293 - must only do the bare minimum to allow execution to continue to
295 - this is almost never needed
296 - return normally from this function
299 - purpose: set up the machine ready for running board_init_r():
300 i.e. SDRAM and serial UART
301 - global_data is available
303 - BSS is not available, so you cannot use global/static variables,
304 only stack variables and global_data
306 Non-SPL-specific notes:
307 - dram_init() is called to set up DRAM. If already done in SPL this
311 - you can override the entire board_init_f() function with your own
313 - preloader_console_init() can be called here in extremis
314 - should set up SDRAM, and anything needed to make the UART work
315 - these is no need to clear BSS, it will be done by crt0.S
316 - must return normally from this function (don't call board_init_r()
319 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
320 this point the stack and global_data are relocated to below
321 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
325 - purpose: main execution, common code
326 - global_data is available
328 - BSS is available, all static/global variables can be used
329 - execution eventually continues to main_loop()
331 Non-SPL-specific notes:
332 - U-Boot is relocated to the top of memory and is now running from
336 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
337 CONFIG_SPL_STACK_R_ADDR points into SDRAM
338 - preloader_console_init() can be called here - typically this is
339 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
340 spl_board_init() function containing this call
341 - loads U-Boot or (in falcon mode) Linux
345 Configuration Options:
346 ----------------------
348 Configuration depends on the combination of board and CPU type; all
349 such information is kept in a configuration file
350 "include/configs/<board_name>.h".
352 Example: For a TQM823L module, all configuration settings are in
353 "include/configs/TQM823L.h".
356 Many of the options are named exactly as the corresponding Linux
357 kernel configuration options. The intention is to make it easier to
358 build a config tool - later.
361 The following options need to be configured:
363 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
365 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
367 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
368 Define exactly one, e.g. CONFIG_ATSTK1002
370 - CPU Module Type: (if CONFIG_COGENT is defined)
371 Define exactly one of
373 --- FIXME --- not tested yet:
374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375 CONFIG_CMA287_23, CONFIG_CMA287_50
377 - Motherboard Type: (if CONFIG_COGENT is defined)
378 Define exactly one of
379 CONFIG_CMA101, CONFIG_CMA102
381 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382 Define one or more of
385 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386 Define one or more of
387 CONFIG_LCD_HEARTBEAT - update a character position on
388 the LCD display every second with
391 - Marvell Family Member
392 CONFIG_SYS_MVFS - define it if you want to enable
393 multiple fs option at one time
394 for marvell soc family
396 - 8xx CPU Options: (if using an MPC8xx CPU)
397 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
398 get_gclk_freq() cannot work
399 e.g. if there is no 32KHz
400 reference PIT/RTC clock
401 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
404 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
405 CONFIG_SYS_8xx_CPUCLK_MIN
406 CONFIG_SYS_8xx_CPUCLK_MAX
407 CONFIG_8xx_CPUCLK_DEFAULT
408 See doc/README.MPC866
410 CONFIG_SYS_MEASURE_CPUCLK
412 Define this to measure the actual CPU clock instead
413 of relying on the correctness of the configured
414 values. Mostly useful for board bringup to make sure
415 the PLL is locked at the intended frequency. Note
416 that this requires a (stable) reference clock (32 kHz
417 RTC clock or CONFIG_SYS_8XX_XIN)
419 CONFIG_SYS_DELAYED_ICACHE
421 Define this option if you want to enable the
422 ICache only when Code runs from RAM.
427 Specifies that the core is a 64-bit PowerPC implementation (implements
428 the "64" category of the Power ISA). This is necessary for ePAPR
429 compliance, among other possible reasons.
431 CONFIG_SYS_FSL_TBCLK_DIV
433 Defines the core time base clock divider ratio compared to the
434 system clock. On most PQ3 devices this is 8, on newer QorIQ
435 devices it can be 16 or 32. The ratio varies from SoC to Soc.
437 CONFIG_SYS_FSL_PCIE_COMPAT
439 Defines the string to utilize when trying to match PCIe device
440 tree nodes for the given platform.
442 CONFIG_SYS_PPC_E500_DEBUG_TLB
444 Enables a temporary TLB entry to be used during boot to work
445 around limitations in e500v1 and e500v2 external debugger
446 support. This reduces the portions of the boot code where
447 breakpoints and single stepping do not work. The value of this
448 symbol should be set to the TLB1 entry to be used for this
451 CONFIG_SYS_FSL_ERRATUM_A004510
453 Enables a workaround for erratum A004510. If set,
454 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
455 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
457 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
458 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
460 Defines one or two SoC revisions (low 8 bits of SVR)
461 for which the A004510 workaround should be applied.
463 The rest of SVR is either not relevant to the decision
464 of whether the erratum is present (e.g. p2040 versus
465 p2041) or is implied by the build target, which controls
466 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
468 See Freescale App Note 4493 for more information about
471 CONFIG_A003399_NOR_WORKAROUND
472 Enables a workaround for IFC erratum A003399. It is only
473 required during NOR boot.
475 CONFIG_A008044_WORKAROUND
476 Enables a workaround for T1040/T1042 erratum A008044. It is only
477 required during NAND boot and valid for Rev 1.0 SoC revision
479 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
481 This is the value to write into CCSR offset 0x18600
482 according to the A004510 workaround.
484 CONFIG_SYS_FSL_DSP_DDR_ADDR
485 This value denotes start offset of DDR memory which is
486 connected exclusively to the DSP cores.
488 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
489 This value denotes start offset of M2 memory
490 which is directly connected to the DSP core.
492 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
493 This value denotes start offset of M3 memory which is directly
494 connected to the DSP core.
496 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
497 This value denotes start offset of DSP CCSR space.
499 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
500 Single Source Clock is clocking mode present in some of FSL SoC's.
501 In this mode, a single differential clock is used to supply
502 clocks to the sysclock, ddrclock and usbclock.
504 CONFIG_SYS_CPC_REINIT_F
505 This CONFIG is defined when the CPC is configured as SRAM at the
506 time of U-boot entry and is required to be re-initialized.
509 Indicates this SoC supports deep sleep feature. If deep sleep is
510 supported, core will start to execute uboot when wakes up.
512 - Generic CPU options:
513 CONFIG_SYS_GENERIC_GLOBAL_DATA
514 Defines global data is initialized in generic board board_init_f().
515 If this macro is defined, global data is created and cleared in
516 generic board board_init_f(). Without this macro, architecture/board
517 should initialize global data before calling board_init_f().
519 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
521 Defines the endianess of the CPU. Implementation of those
522 values is arch specific.
525 Freescale DDR driver in use. This type of DDR controller is
526 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
529 CONFIG_SYS_FSL_DDR_ADDR
530 Freescale DDR memory-mapped register base.
532 CONFIG_SYS_FSL_DDR_EMU
533 Specify emulator support for DDR. Some DDR features such as
534 deskew training are not available.
536 CONFIG_SYS_FSL_DDRC_GEN1
537 Freescale DDR1 controller.
539 CONFIG_SYS_FSL_DDRC_GEN2
540 Freescale DDR2 controller.
542 CONFIG_SYS_FSL_DDRC_GEN3
543 Freescale DDR3 controller.
545 CONFIG_SYS_FSL_DDRC_GEN4
546 Freescale DDR4 controller.
548 CONFIG_SYS_FSL_DDRC_ARM_GEN3
549 Freescale DDR3 controller for ARM-based SoCs.
552 Board config to use DDR1. It can be enabled for SoCs with
553 Freescale DDR1 or DDR2 controllers, depending on the board
557 Board config to use DDR2. It can be eanbeld for SoCs with
558 Freescale DDR2 or DDR3 controllers, depending on the board
562 Board config to use DDR3. It can be enabled for SoCs with
563 Freescale DDR3 or DDR3L controllers.
566 Board config to use DDR3L. It can be enabled for SoCs with
570 Board config to use DDR4. It can be enabled for SoCs with
573 CONFIG_SYS_FSL_IFC_BE
574 Defines the IFC controller register space as Big Endian
576 CONFIG_SYS_FSL_IFC_LE
577 Defines the IFC controller register space as Little Endian
579 CONFIG_SYS_FSL_PBL_PBI
580 It enables addition of RCW (Power on reset configuration) in built image.
581 Please refer doc/README.pblimage for more details
583 CONFIG_SYS_FSL_PBL_RCW
584 It adds PBI(pre-boot instructions) commands in u-boot build image.
585 PBI commands can be used to configure SoC before it starts the execution.
586 Please refer doc/README.pblimage for more details
589 It adds a target to create boot binary having SPL binary in PBI format
590 concatenated with u-boot binary.
592 CONFIG_SYS_FSL_DDR_BE
593 Defines the DDR controller register space as Big Endian
595 CONFIG_SYS_FSL_DDR_LE
596 Defines the DDR controller register space as Little Endian
598 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
599 Physical address from the view of DDR controllers. It is the
600 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
601 it could be different for ARM SoCs.
603 CONFIG_SYS_FSL_DDR_INTLV_256B
604 DDR controller interleaving on 256-byte. This is a special
605 interleaving mode, handled by Dickens for Freescale layerscape
608 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
609 Number of controllers used as main memory.
611 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
612 Number of controllers used for other than main memory.
614 CONFIG_SYS_FSL_SEC_BE
615 Defines the SEC controller register space as Big Endian
617 CONFIG_SYS_FSL_SEC_LE
618 Defines the SEC controller register space as Little Endian
620 - Intel Monahans options:
621 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
623 Defines the Monahans run mode to oscillator
624 ratio. Valid values are 8, 16, 24, 31. The core
625 frequency is this value multiplied by 13 MHz.
627 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
629 Defines the Monahans turbo mode to oscillator
630 ratio. Valid values are 1 (default if undefined) and
631 2. The core frequency as calculated above is multiplied
635 CONFIG_SYS_INIT_SP_OFFSET
637 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
638 pointer. This is needed for the temporary stack before
641 CONFIG_SYS_MIPS_CACHE_MODE
643 Cache operation mode for the MIPS CPU.
644 See also arch/mips/include/asm/mipsregs.h.
646 CONF_CM_CACHABLE_NO_WA
649 CONF_CM_CACHABLE_NONCOHERENT
653 CONF_CM_CACHABLE_ACCELERATED
655 CONFIG_SYS_XWAY_EBU_BOOTCFG
657 Special option for Lantiq XWAY SoCs for booting from NOR flash.
658 See also arch/mips/cpu/mips32/start.S.
660 CONFIG_XWAY_SWAP_BYTES
662 Enable compilation of tools/xway-swap-bytes needed for Lantiq
663 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
664 be swapped if a flash programmer is used.
667 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
669 Select high exception vectors of the ARM core, e.g., do not
670 clear the V bit of the c1 register of CP15.
672 CONFIG_SYS_THUMB_BUILD
674 Use this flag to build U-Boot using the Thumb instruction
675 set for ARM architectures. Thumb instruction set provides
676 better code density. For ARM architectures that support
677 Thumb2 this flag will result in Thumb2 code generated by
680 CONFIG_ARM_ERRATA_716044
681 CONFIG_ARM_ERRATA_742230
682 CONFIG_ARM_ERRATA_743622
683 CONFIG_ARM_ERRATA_751472
684 CONFIG_ARM_ERRATA_794072
685 CONFIG_ARM_ERRATA_761320
687 If set, the workarounds for these ARM errata are applied early
688 during U-Boot startup. Note that these options force the
689 workarounds to be applied; no CPU-type/version detection
690 exists, unlike the similar options in the Linux kernel. Do not
691 set these options unless they apply!
693 NOTE: The following can be machine specific errata. These
694 do have ability to provide rudimentary version and machine
695 specific checks, but expect no product checks.
696 CONFIG_ARM_ERRATA_798870
699 CONFIG_TEGRA_SUPPORT_NON_SECURE
701 Support executing U-Boot in non-secure (NS) mode. Certain
702 impossible actions will be skipped if the CPU is in NS mode,
703 such as ARM architectural timer initialization.
706 Driver model is a new framework for devices in U-Boot
707 introduced in early 2014. U-Boot is being progressively
708 moved over to this. It offers a consistent device structure,
709 supports grouping devices into classes and has built-in
710 handling of platform data and device tree.
712 To enable transition to driver model in a relatively
713 painful fashion, each subsystem can be independently
714 switched between the legacy/ad-hoc approach and the new
715 driver model using the options below. Also, many uclass
716 interfaces include compatibility features which may be
717 removed once the conversion of that subsystem is complete.
718 As a result, the API provided by the subsystem may in fact
719 not change with driver model.
721 See doc/driver-model/README.txt for more information.
725 Enable driver model. This brings in the core support,
726 including scanning of platform data on start-up. If
727 CONFIG_OF_CONTROL is enabled, the device tree will be
728 scanned also when available.
732 Enable driver model test commands. These allow you to print
733 out the driver model tree and the uclasses.
737 Enable some demo devices and the 'demo' command. These are
738 really only useful for playing around while trying to
739 understand driver model in sandbox.
743 Enable driver model in SPL. You will need to provide a
744 suitable malloc() implementation. If you are not using the
745 full malloc() enabled by CONFIG_SYS_SPL_MALLOC_START,
746 consider using CONFIG_SYS_MALLOC_SIMPLE. In that case you
747 must provide CONFIG_SYS_MALLOC_F_LEN to set the size.
748 In most cases driver model will only allocate a few uclasses
749 and devices in SPL, so 1KB should be enable. See
750 CONFIG_SYS_MALLOC_F_LEN for more details on how to enable
755 Enable driver model for serial. This replaces
756 drivers/serial/serial.c with the serial uclass, which
757 implements serial_putc() etc. The uclass interface is
758 defined in include/serial.h.
762 Enable driver model for GPIO access. The standard GPIO
763 interface (gpio_get_value(), etc.) is then implemented by
764 the GPIO uclass. Drivers provide methods to query the
765 particular GPIOs that they provide. The uclass interface
766 is defined in include/asm-generic/gpio.h.
770 Enable driver model for SPI. The SPI slave interface
771 (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
772 the SPI uclass. Drivers provide methods to access the SPI
773 buses that they control. The uclass interface is defined in
774 include/spi.h. The existing spi_slave structure is attached
775 as 'parent data' to every slave on each bus. Slaves
776 typically use driver-private data instead of extending the
781 Enable driver model for SPI flash. This SPI flash interface
782 (spi_flash_probe(), spi_flash_write(), etc.) is then
783 implemented by the SPI flash uclass. There is one standard
784 SPI flash driver which knows how to probe most chips
785 supported by U-Boot. The uclass interface is defined in
786 include/spi_flash.h, but is currently fully compatible
787 with the old interface to avoid confusion and duplication
788 during the transition parent. SPI and SPI flash must be
789 enabled together (it is not possible to use driver model
790 for one and not the other).
794 Enable driver model for the Chrome OS EC interface. This
795 allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
796 but otherwise makes few changes. Since cros_ec also supports
797 I2C and LPC (which don't support driver model yet), a full
798 conversion is not yet possible.
801 ** Code size options: The following options are enabled by
802 default except in SPL. Enable them explicitly to get these
807 Enable the dm_warn() function. This can use up quite a bit
808 of space for its strings.
812 Enable registering a serial device with the stdio library.
814 CONFIG_DM_DEVICE_REMOVE
816 Enable removing of devices.
818 - Linux Kernel Interface:
821 U-Boot stores all clock information in Hz
822 internally. For binary compatibility with older Linux
823 kernels (which expect the clocks passed in the
824 bd_info data to be in MHz) the environment variable
825 "clocks_in_mhz" can be defined so that U-Boot
826 converts clock data to MHZ before passing it to the
828 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
829 "clocks_in_mhz=1" is automatically included in the
832 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
834 When transferring memsize parameter to Linux, some versions
835 expect it to be in bytes, others in MB.
836 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
840 New kernel versions are expecting firmware settings to be
841 passed using flattened device trees (based on open firmware
845 * New libfdt-based support
846 * Adds the "fdt" command
847 * The bootm command automatically updates the fdt
849 OF_CPU - The proper name of the cpus node (only required for
850 MPC512X and MPC5xxx based boards).
851 OF_SOC - The proper name of the soc node (only required for
852 MPC512X and MPC5xxx based boards).
853 OF_TBCLK - The timebase frequency.
854 OF_STDOUT_PATH - The path to the console device
856 boards with QUICC Engines require OF_QE to set UCC MAC
859 CONFIG_OF_BOARD_SETUP
861 Board code has addition modification that it wants to make
862 to the flat device tree before handing it off to the kernel
864 CONFIG_OF_SYSTEM_SETUP
866 Other code has addition modification that it wants to make
867 to the flat device tree before handing it off to the kernel.
868 This causes ft_system_setup() to be called before booting
873 This define fills in the correct boot CPU in the boot
874 param header, the default value is zero if undefined.
878 U-Boot can detect if an IDE device is present or not.
879 If not, and this new config option is activated, U-Boot
880 removes the ATA node from the DTS before booting Linux,
881 so the Linux IDE driver does not probe the device and
882 crash. This is needed for buggy hardware (uc101) where
883 no pull down resistor is connected to the signal IDE5V_DD7.
885 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
887 This setting is mandatory for all boards that have only one
888 machine type and must be used to specify the machine type
889 number as it appears in the ARM machine registry
890 (see http://www.arm.linux.org.uk/developer/machines/).
891 Only boards that have multiple machine types supported
892 in a single configuration file and the machine type is
893 runtime discoverable, do not have to use this setting.
895 - vxWorks boot parameters:
897 bootvx constructs a valid bootline using the following
898 environments variables: bootfile, ipaddr, serverip, hostname.
899 It loads the vxWorks image pointed bootfile.
901 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
902 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
903 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
904 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
906 CONFIG_SYS_VXWORKS_ADD_PARAMS
908 Add it at the end of the bootline. E.g "u=username pw=secret"
910 Note: If a "bootargs" environment is defined, it will overwride
911 the defaults discussed just above.
913 - Cache Configuration:
914 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
915 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
916 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
918 - Cache Configuration for ARM:
919 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
921 CONFIG_SYS_PL310_BASE - Physical base address of PL310
922 controller register space
927 Define this if you want support for Amba PrimeCell PL010 UARTs.
931 Define this if you want support for Amba PrimeCell PL011 UARTs.
935 If you have Amba PrimeCell PL011 UARTs, set this variable to
936 the clock speed of the UARTs.
940 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
941 define this to a list of base addresses for each (supported)
942 port. See e.g. include/configs/versatile.h
944 CONFIG_PL011_SERIAL_RLCR
946 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
947 have separate receive and transmit line control registers. Set
948 this variable to initialize the extra register.
950 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
952 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
953 boot loader that has already initialized the UART. Define this
954 variable to flush the UART at init time.
956 CONFIG_SERIAL_HW_FLOW_CONTROL
958 Define this variable to enable hw flow control in serial driver.
959 Current user of this option is drivers/serial/nsl16550.c driver
962 Depending on board, define exactly one serial port
963 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
964 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
965 console by defining CONFIG_8xx_CONS_NONE
967 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
968 port routines must be defined elsewhere
969 (i.e. serial_init(), serial_getc(), ...)
972 Enables console device for a color framebuffer. Needs following
973 defines (cf. smiLynxEM, i8042)
974 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
976 VIDEO_HW_RECTFILL graphic chip supports
979 VIDEO_HW_BITBLT graphic chip supports
980 bit-blit (cf. smiLynxEM)
981 VIDEO_VISIBLE_COLS visible pixel columns
983 VIDEO_VISIBLE_ROWS visible pixel rows
984 VIDEO_PIXEL_SIZE bytes per pixel
985 VIDEO_DATA_FORMAT graphic data format
986 (0-5, cf. cfb_console.c)
987 VIDEO_FB_ADRS framebuffer address
988 VIDEO_KBD_INIT_FCT keyboard int fct
989 (i.e. i8042_kbd_init())
990 VIDEO_TSTC_FCT test char fct
992 VIDEO_GETC_FCT get char fct
994 CONFIG_CONSOLE_CURSOR cursor drawing on/off
995 (requires blink timer
997 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
998 CONFIG_CONSOLE_TIME display time/date info in
1000 (requires CONFIG_CMD_DATE)
1001 CONFIG_VIDEO_LOGO display Linux logo in
1003 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
1004 linux_logo.h for logo.
1005 Requires CONFIG_VIDEO_LOGO
1006 CONFIG_CONSOLE_EXTRA_INFO
1007 additional board info beside
1010 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
1011 a limited number of ANSI escape sequences (cursor control,
1012 erase functions and limited graphics rendition control).
1014 When CONFIG_CFB_CONSOLE is defined, video console is
1015 default i/o. Serial console can be forced with
1016 environment 'console=serial'.
1018 When CONFIG_SILENT_CONSOLE is defined, all console
1019 messages (by U-Boot and Linux!) can be silenced with
1020 the "silent" environment variable. See
1021 doc/README.silent for more information.
1023 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
1025 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
1029 CONFIG_BAUDRATE - in bps
1030 Select one of the baudrates listed in
1031 CONFIG_SYS_BAUDRATE_TABLE, see below.
1032 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
1034 - Console Rx buffer length
1035 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
1036 the maximum receive buffer length for the SMC.
1037 This option is actual only for 82xx and 8xx possible.
1038 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
1039 must be defined, to setup the maximum idle timeout for
1042 - Pre-Console Buffer:
1043 Prior to the console being initialised (i.e. serial UART
1044 initialised etc) all console output is silently discarded.
1045 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
1046 buffer any console messages prior to the console being
1047 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
1048 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
1049 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
1050 bytes are output before the console is initialised, the
1051 earlier bytes are discarded.
1053 'Sane' compilers will generate smaller code if
1054 CONFIG_PRE_CON_BUF_SZ is a power of 2
1056 - Safe printf() functions
1057 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
1058 the printf() functions. These are defined in
1059 include/vsprintf.h and include snprintf(), vsnprintf() and
1060 so on. Code size increase is approximately 300-500 bytes.
1061 If this option is not given then these functions will
1062 silently discard their buffer size argument - this means
1063 you are not getting any overflow checking in this case.
1065 - Boot Delay: CONFIG_BOOTDELAY - in seconds
1066 Delay before automatically booting the default image;
1067 set to -1 to disable autoboot.
1068 set to -2 to autoboot with no delay and not check for abort
1069 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
1071 See doc/README.autoboot for these options that
1072 work with CONFIG_BOOTDELAY. None are required.
1073 CONFIG_BOOT_RETRY_TIME
1074 CONFIG_BOOT_RETRY_MIN
1075 CONFIG_AUTOBOOT_KEYED
1076 CONFIG_AUTOBOOT_PROMPT
1077 CONFIG_AUTOBOOT_DELAY_STR
1078 CONFIG_AUTOBOOT_STOP_STR
1079 CONFIG_AUTOBOOT_DELAY_STR2
1080 CONFIG_AUTOBOOT_STOP_STR2
1081 CONFIG_ZERO_BOOTDELAY_CHECK
1082 CONFIG_RESET_TO_RETRY
1086 Only needed when CONFIG_BOOTDELAY is enabled;
1087 define a command string that is automatically executed
1088 when no character is read on the console interface
1089 within "Boot Delay" after reset.
1092 This can be used to pass arguments to the bootm
1093 command. The value of CONFIG_BOOTARGS goes into the
1094 environment value "bootargs".
1096 CONFIG_RAMBOOT and CONFIG_NFSBOOT
1097 The value of these goes into the environment as
1098 "ramboot" and "nfsboot" respectively, and can be used
1099 as a convenience, when switching between booting from
1103 CONFIG_BOOTCOUNT_LIMIT
1104 Implements a mechanism for detecting a repeating reboot
1106 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
1108 CONFIG_BOOTCOUNT_ENV
1109 If no softreset save registers are found on the hardware
1110 "bootcount" is stored in the environment. To prevent a
1111 saveenv on all reboots, the environment variable
1112 "upgrade_available" is used. If "upgrade_available" is
1113 0, "bootcount" is always 0, if "upgrade_available" is
1114 1 "bootcount" is incremented in the environment.
1115 So the Userspace Applikation must set the "upgrade_available"
1116 and "bootcount" variable to 0, if a boot was successfully.
1118 - Pre-Boot Commands:
1121 When this option is #defined, the existence of the
1122 environment variable "preboot" will be checked
1123 immediately before starting the CONFIG_BOOTDELAY
1124 countdown and/or running the auto-boot command resp.
1125 entering interactive mode.
1127 This feature is especially useful when "preboot" is
1128 automatically generated or modified. For an example
1129 see the LWMON board specific code: here "preboot" is
1130 modified when the user holds down a certain
1131 combination of keys on the (special) keyboard when
1134 - Serial Download Echo Mode:
1136 If defined to 1, all characters received during a
1137 serial download (using the "loads" command) are
1138 echoed back. This might be needed by some terminal
1139 emulations (like "cu"), but may as well just take
1140 time on others. This setting #define's the initial
1141 value of the "loads_echo" environment variable.
1143 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
1144 CONFIG_KGDB_BAUDRATE
1145 Select one of the baudrates listed in
1146 CONFIG_SYS_BAUDRATE_TABLE, see below.
1148 - Monitor Functions:
1149 Monitor commands can be included or excluded
1150 from the build by using the #include files
1151 <config_cmd_all.h> and #undef'ing unwanted
1152 commands, or using <config_cmd_default.h>
1153 and augmenting with additional #define's
1154 for wanted commands.
1156 The default command configuration includes all commands
1157 except those marked below with a "*".
1159 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
1160 CONFIG_CMD_ASKENV * ask for env variable
1161 CONFIG_CMD_BDI bdinfo
1162 CONFIG_CMD_BEDBUG * Include BedBug Debugger
1163 CONFIG_CMD_BMP * BMP support
1164 CONFIG_CMD_BSP * Board specific commands
1165 CONFIG_CMD_BOOTD bootd
1166 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
1167 CONFIG_CMD_CACHE * icache, dcache
1168 CONFIG_CMD_CLK * clock command support
1169 CONFIG_CMD_CONSOLE coninfo
1170 CONFIG_CMD_CRC32 * crc32
1171 CONFIG_CMD_DATE * support for RTC, date/time...
1172 CONFIG_CMD_DHCP * DHCP support
1173 CONFIG_CMD_DIAG * Diagnostics
1174 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
1175 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
1176 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
1177 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
1178 CONFIG_CMD_DTT * Digital Therm and Thermostat
1179 CONFIG_CMD_ECHO echo arguments
1180 CONFIG_CMD_EDITENV edit env variable
1181 CONFIG_CMD_EEPROM * EEPROM read/write support
1182 CONFIG_CMD_ELF * bootelf, bootvx
1183 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
1184 CONFIG_CMD_ENV_FLAGS * display details about env flags
1185 CONFIG_CMD_ENV_EXISTS * check existence of env variable
1186 CONFIG_CMD_EXPORTENV * export the environment
1187 CONFIG_CMD_EXT2 * ext2 command support
1188 CONFIG_CMD_EXT4 * ext4 command support
1189 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
1190 that work for multiple fs types
1191 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
1192 CONFIG_CMD_SAVEENV saveenv
1193 CONFIG_CMD_FDC * Floppy Disk Support
1194 CONFIG_CMD_FAT * FAT command support
1195 CONFIG_CMD_FLASH flinfo, erase, protect
1196 CONFIG_CMD_FPGA FPGA device initialization support
1197 CONFIG_CMD_FUSE * Device fuse support
1198 CONFIG_CMD_GETTIME * Get time since boot
1199 CONFIG_CMD_GO * the 'go' command (exec code)
1200 CONFIG_CMD_GREPENV * search environment
1201 CONFIG_CMD_HASH * calculate hash / digest
1202 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1203 CONFIG_CMD_I2C * I2C serial bus support
1204 CONFIG_CMD_IDE * IDE harddisk support
1205 CONFIG_CMD_IMI iminfo
1206 CONFIG_CMD_IMLS List all images found in NOR flash
1207 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1208 CONFIG_CMD_IMMAP * IMMR dump support
1209 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1210 CONFIG_CMD_IMPORTENV * import an environment
1211 CONFIG_CMD_INI * import data from an ini file into the env
1212 CONFIG_CMD_IRQ * irqinfo
1213 CONFIG_CMD_ITEST Integer/string test of 2 values
1214 CONFIG_CMD_JFFS2 * JFFS2 Support
1215 CONFIG_CMD_KGDB * kgdb
1216 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1217 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1219 CONFIG_CMD_LOADB loadb
1220 CONFIG_CMD_LOADS loads
1221 CONFIG_CMD_MD5SUM * print md5 message digest
1222 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1223 CONFIG_CMD_MEMINFO * Display detailed memory information
1224 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1226 CONFIG_CMD_MEMTEST * mtest
1227 CONFIG_CMD_MISC Misc functions like sleep etc
1228 CONFIG_CMD_MMC * MMC memory mapped support
1229 CONFIG_CMD_MII * MII utility commands
1230 CONFIG_CMD_MTDPARTS * MTD partition support
1231 CONFIG_CMD_NAND * NAND support
1232 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1233 CONFIG_CMD_NFS NFS support
1234 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1235 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1236 CONFIG_CMD_PCI * pciinfo
1237 CONFIG_CMD_PCMCIA * PCMCIA support
1238 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1240 CONFIG_CMD_PORTIO * Port I/O
1241 CONFIG_CMD_READ * Read raw data from partition
1242 CONFIG_CMD_REGINFO * Register dump
1243 CONFIG_CMD_RUN run command in env variable
1244 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1245 CONFIG_CMD_SAVES * save S record dump
1246 CONFIG_CMD_SCSI * SCSI Support
1247 CONFIG_CMD_SDRAM * print SDRAM configuration information
1248 (requires CONFIG_CMD_I2C)
1249 CONFIG_CMD_SETGETDCR Support for DCR Register access
1251 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1252 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1253 (requires CONFIG_CMD_MEMORY)
1254 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1255 CONFIG_CMD_SOURCE "source" command Support
1256 CONFIG_CMD_SPI * SPI serial bus support
1257 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1258 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1259 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1260 CONFIG_CMD_TIMER * access to the system tick timer
1261 CONFIG_CMD_USB * USB support
1262 CONFIG_CMD_CDP * Cisco Discover Protocol support
1263 CONFIG_CMD_MFSL * Microblaze FSL support
1264 CONFIG_CMD_XIMG Load part of Multi Image
1265 CONFIG_CMD_UUID * Generate random UUID or GUID string
1267 EXAMPLE: If you want all functions except of network
1268 support you can write:
1270 #include "config_cmd_all.h"
1271 #undef CONFIG_CMD_NET
1274 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1276 Note: Don't enable the "icache" and "dcache" commands
1277 (configuration option CONFIG_CMD_CACHE) unless you know
1278 what you (and your U-Boot users) are doing. Data
1279 cache cannot be enabled on systems like the 8xx or
1280 8260 (where accesses to the IMMR region must be
1281 uncached), and it cannot be disabled on all other
1282 systems where we (mis-) use the data cache to hold an
1283 initial stack and some data.
1286 XXX - this list needs to get updated!
1288 - Regular expression support:
1290 If this variable is defined, U-Boot is linked against
1291 the SLRE (Super Light Regular Expression) library,
1292 which adds regex support to some commands, as for
1293 example "env grep" and "setexpr".
1297 If this variable is defined, U-Boot will use a device tree
1298 to configure its devices, instead of relying on statically
1299 compiled #defines in the board file. This option is
1300 experimental and only available on a few boards. The device
1301 tree is available in the global data as gd->fdt_blob.
1303 U-Boot needs to get its device tree from somewhere. This can
1304 be done using one of the two options below:
1307 If this variable is defined, U-Boot will embed a device tree
1308 binary in its image. This device tree file should be in the
1309 board directory and called <soc>-<board>.dts. The binary file
1310 is then picked up in board_init_f() and made available through
1311 the global data structure as gd->blob.
1314 If this variable is defined, U-Boot will build a device tree
1315 binary. It will be called u-boot.dtb. Architecture-specific
1316 code will locate it at run-time. Generally this works by:
1318 cat u-boot.bin u-boot.dtb >image.bin
1320 and in fact, U-Boot does this for you, creating a file called
1321 u-boot-dtb.bin which is useful in the common case. You can
1322 still use the individual files if you need something more
1327 If this variable is defined, it enables watchdog
1328 support for the SoC. There must be support in the SoC
1329 specific code for a watchdog. For the 8xx and 8260
1330 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1331 register. When supported for a specific SoC is
1332 available, then no further board specific code should
1333 be needed to use it.
1336 When using a watchdog circuitry external to the used
1337 SoC, then define this variable and provide board
1338 specific code for the "hw_watchdog_reset" function.
1340 CONFIG_AT91_HW_WDT_TIMEOUT
1341 specify the timeout in seconds. default 2 seconds.
1344 CONFIG_VERSION_VARIABLE
1345 If this variable is defined, an environment variable
1346 named "ver" is created by U-Boot showing the U-Boot
1347 version as printed by the "version" command.
1348 Any change to this variable will be reverted at the
1353 When CONFIG_CMD_DATE is selected, the type of the RTC
1354 has to be selected, too. Define exactly one of the
1357 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1358 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1359 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1360 CONFIG_RTC_MC146818 - use MC146818 RTC
1361 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1362 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1363 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1364 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1365 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1366 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1367 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1368 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1369 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1372 Note that if the RTC uses I2C, then the I2C interface
1373 must also be configured. See I2C Support, below.
1376 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1378 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1379 chip-ngpio pairs that tell the PCA953X driver the number of
1380 pins supported by a particular chip.
1382 Note that if the GPIO device uses I2C, then the I2C interface
1383 must also be configured. See I2C Support, below.
1386 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1387 accesses and can checksum them or write a list of them out
1388 to memory. See the 'iotrace' command for details. This is
1389 useful for testing device drivers since it can confirm that
1390 the driver behaves the same way before and after a code
1391 change. Currently this is supported on sandbox and arm. To
1392 add support for your architecture, add '#include <iotrace.h>'
1393 to the bottom of arch/<arch>/include/asm/io.h and test.
1395 Example output from the 'iotrace stats' command is below.
1396 Note that if the trace buffer is exhausted, the checksum will
1397 still continue to operate.
1400 Start: 10000000 (buffer start address)
1401 Size: 00010000 (buffer size)
1402 Offset: 00000120 (current buffer offset)
1403 Output: 10000120 (start + offset)
1404 Count: 00000018 (number of trace records)
1405 CRC32: 9526fb66 (CRC32 of all trace records)
1407 - Timestamp Support:
1409 When CONFIG_TIMESTAMP is selected, the timestamp
1410 (date and time) of an image is printed by image
1411 commands like bootm or iminfo. This option is
1412 automatically enabled when you select CONFIG_CMD_DATE .
1414 - Partition Labels (disklabels) Supported:
1415 Zero or more of the following:
1416 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1417 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1418 Intel architecture, USB sticks, etc.
1419 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1420 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1421 bootloader. Note 2TB partition limit; see
1423 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1425 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1426 CONFIG_CMD_SCSI) you must configure support for at
1427 least one non-MTD partition type as well.
1430 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1431 board configurations files but used nowhere!
1433 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1434 be performed by calling the function
1435 ide_set_reset(int reset)
1436 which has to be defined in a board specific file
1441 Set this to enable ATAPI support.
1446 Set this to enable support for disks larger than 137GB
1447 Also look at CONFIG_SYS_64BIT_LBA.
1448 Whithout these , LBA48 support uses 32bit variables and will 'only'
1449 support disks up to 2.1TB.
1451 CONFIG_SYS_64BIT_LBA:
1452 When enabled, makes the IDE subsystem use 64bit sector addresses.
1456 At the moment only there is only support for the
1457 SYM53C8XX SCSI controller; define
1458 CONFIG_SCSI_SYM53C8XX to enable it.
1460 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1461 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1462 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1463 maximum numbers of LUNs, SCSI ID's and target
1465 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1467 The environment variable 'scsidevs' is set to the number of
1468 SCSI devices found during the last scan.
1470 - NETWORK Support (PCI):
1472 Support for Intel 8254x/8257x gigabit chips.
1475 Utility code for direct access to the SPI bus on Intel 8257x.
1476 This does not do anything useful unless you set at least one
1477 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1479 CONFIG_E1000_SPI_GENERIC
1480 Allow generic access to the SPI bus on the Intel 8257x, for
1481 example with the "sspi" command.
1484 Management command for E1000 devices. When used on devices
1485 with SPI support you can reprogram the EEPROM from U-Boot.
1487 CONFIG_E1000_FALLBACK_MAC
1488 default MAC for empty EEPROM after production.
1491 Support for Intel 82557/82559/82559ER chips.
1492 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1493 write routine for first time initialisation.
1496 Support for Digital 2114x chips.
1497 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1498 modem chip initialisation (KS8761/QS6611).
1501 Support for National dp83815 chips.
1504 Support for National dp8382[01] gigabit chips.
1506 - NETWORK Support (other):
1508 CONFIG_DRIVER_AT91EMAC
1509 Support for AT91RM9200 EMAC.
1512 Define this to use reduced MII inteface
1514 CONFIG_DRIVER_AT91EMAC_QUIET
1515 If this defined, the driver is quiet.
1516 The driver doen't show link status messages.
1518 CONFIG_CALXEDA_XGMAC
1519 Support for the Calxeda XGMAC device
1522 Support for SMSC's LAN91C96 chips.
1524 CONFIG_LAN91C96_BASE
1525 Define this to hold the physical address
1526 of the LAN91C96's I/O space
1528 CONFIG_LAN91C96_USE_32_BIT
1529 Define this to enable 32 bit addressing
1532 Support for SMSC's LAN91C111 chip
1534 CONFIG_SMC91111_BASE
1535 Define this to hold the physical address
1536 of the device (I/O space)
1538 CONFIG_SMC_USE_32_BIT
1539 Define this if data bus is 32 bits
1541 CONFIG_SMC_USE_IOFUNCS
1542 Define this to use i/o functions instead of macros
1543 (some hardware wont work with macros)
1545 CONFIG_DRIVER_TI_EMAC
1546 Support for davinci emac
1548 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1549 Define this if you have more then 3 PHYs.
1552 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1554 CONFIG_FTGMAC100_EGIGA
1555 Define this to use GE link update with gigabit PHY.
1556 Define this if FTGMAC100 is connected to gigabit PHY.
1557 If your system has 10/100 PHY only, it might not occur
1558 wrong behavior. Because PHY usually return timeout or
1559 useless data when polling gigabit status and gigabit
1560 control registers. This behavior won't affect the
1561 correctnessof 10/100 link speed update.
1564 Support for SMSC's LAN911x and LAN921x chips
1567 Define this to hold the physical address
1568 of the device (I/O space)
1570 CONFIG_SMC911X_32_BIT
1571 Define this if data bus is 32 bits
1573 CONFIG_SMC911X_16_BIT
1574 Define this if data bus is 16 bits. If your processor
1575 automatically converts one 32 bit word to two 16 bit
1576 words you may also try CONFIG_SMC911X_32_BIT.
1579 Support for Renesas on-chip Ethernet controller
1581 CONFIG_SH_ETHER_USE_PORT
1582 Define the number of ports to be used
1584 CONFIG_SH_ETHER_PHY_ADDR
1585 Define the ETH PHY's address
1587 CONFIG_SH_ETHER_CACHE_WRITEBACK
1588 If this option is set, the driver enables cache flush.
1592 Support for PWM modul on the imx6.
1596 Support TPM devices.
1599 Support for i2c bus TPM devices. Only one device
1600 per system is supported at this time.
1602 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1603 Define the the i2c bus number for the TPM device
1605 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1606 Define the TPM's address on the i2c bus
1608 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1609 Define the burst count bytes upper limit
1611 CONFIG_TPM_ATMEL_TWI
1612 Support for Atmel TWI TPM device. Requires I2C support.
1615 Support for generic parallel port TPM devices. Only one device
1616 per system is supported at this time.
1618 CONFIG_TPM_TIS_BASE_ADDRESS
1619 Base address where the generic TPM device is mapped
1620 to. Contemporary x86 systems usually map it at
1624 Add tpm monitor functions.
1625 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1626 provides monitor access to authorized functions.
1629 Define this to enable the TPM support library which provides
1630 functional interfaces to some TPM commands.
1631 Requires support for a TPM device.
1633 CONFIG_TPM_AUTH_SESSIONS
1634 Define this to enable authorized functions in the TPM library.
1635 Requires CONFIG_TPM and CONFIG_SHA1.
1638 At the moment only the UHCI host controller is
1639 supported (PIP405, MIP405, MPC5200); define
1640 CONFIG_USB_UHCI to enable it.
1641 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1642 and define CONFIG_USB_STORAGE to enable the USB
1645 Supported are USB Keyboards and USB Floppy drives
1647 MPC5200 USB requires additional defines:
1649 for 528 MHz Clock: 0x0001bbbb
1653 for differential drivers: 0x00001000
1654 for single ended drivers: 0x00005000
1655 for differential drivers on PSC3: 0x00000100
1656 for single ended drivers on PSC3: 0x00004100
1657 CONFIG_SYS_USB_EVENT_POLL
1658 May be defined to allow interrupt polling
1659 instead of using asynchronous interrupts
1661 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1662 txfilltuning field in the EHCI controller on reset.
1664 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1665 HW module registers.
1668 Define the below if you wish to use the USB console.
1669 Once firmware is rebuilt from a serial console issue the
1670 command "setenv stdin usbtty; setenv stdout usbtty" and
1671 attach your USB cable. The Unix command "dmesg" should print
1672 it has found a new device. The environment variable usbtty
1673 can be set to gserial or cdc_acm to enable your device to
1674 appear to a USB host as a Linux gserial device or a
1675 Common Device Class Abstract Control Model serial device.
1676 If you select usbtty = gserial you should be able to enumerate
1678 # modprobe usbserial vendor=0xVendorID product=0xProductID
1679 else if using cdc_acm, simply setting the environment
1680 variable usbtty to be cdc_acm should suffice. The following
1681 might be defined in YourBoardName.h
1684 Define this to build a UDC device
1687 Define this to have a tty type of device available to
1688 talk to the UDC device
1691 Define this to enable the high speed support for usb
1692 device and usbtty. If this feature is enabled, a routine
1693 int is_usbd_high_speed(void)
1694 also needs to be defined by the driver to dynamically poll
1695 whether the enumeration has succeded at high speed or full
1698 CONFIG_SYS_CONSOLE_IS_IN_ENV
1699 Define this if you want stdin, stdout &/or stderr to
1703 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1704 Derive USB clock from external clock "blah"
1705 - CONFIG_SYS_USB_EXTC_CLK 0x02
1707 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1708 Derive USB clock from brgclk
1709 - CONFIG_SYS_USB_BRG_CLK 0x04
1711 If you have a USB-IF assigned VendorID then you may wish to
1712 define your own vendor specific values either in BoardName.h
1713 or directly in usbd_vendor_info.h. If you don't define
1714 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1715 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1716 should pretend to be a Linux device to it's target host.
1718 CONFIG_USBD_MANUFACTURER
1719 Define this string as the name of your company for
1720 - CONFIG_USBD_MANUFACTURER "my company"
1722 CONFIG_USBD_PRODUCT_NAME
1723 Define this string as the name of your product
1724 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1726 CONFIG_USBD_VENDORID
1727 Define this as your assigned Vendor ID from the USB
1728 Implementors Forum. This *must* be a genuine Vendor ID
1729 to avoid polluting the USB namespace.
1730 - CONFIG_USBD_VENDORID 0xFFFF
1732 CONFIG_USBD_PRODUCTID
1733 Define this as the unique Product ID
1735 - CONFIG_USBD_PRODUCTID 0xFFFF
1737 - ULPI Layer Support:
1738 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1739 the generic ULPI layer. The generic layer accesses the ULPI PHY
1740 via the platform viewport, so you need both the genric layer and
1741 the viewport enabled. Currently only Chipidea/ARC based
1742 viewport is supported.
1743 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1744 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1745 If your ULPI phy needs a different reference clock than the
1746 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1747 the appropriate value in Hz.
1750 The MMC controller on the Intel PXA is supported. To
1751 enable this define CONFIG_MMC. The MMC can be
1752 accessed from the boot prompt by mapping the device
1753 to physical memory similar to flash. Command line is
1754 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1755 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1758 Support for Renesas on-chip MMCIF controller
1760 CONFIG_SH_MMCIF_ADDR
1761 Define the base address of MMCIF registers
1764 Define the clock frequency for MMCIF
1767 Enable the generic MMC driver
1769 CONFIG_SUPPORT_EMMC_BOOT
1770 Enable some additional features of the eMMC boot partitions.
1772 CONFIG_SUPPORT_EMMC_RPMB
1773 Enable the commands for reading, writing and programming the
1774 key for the Replay Protection Memory Block partition in eMMC.
1776 - USB Device Firmware Update (DFU) class support:
1778 This enables the USB portion of the DFU USB class
1781 This enables the command "dfu" which is used to have
1782 U-Boot create a DFU class device via USB. This command
1783 requires that the "dfu_alt_info" environment variable be
1784 set and define the alt settings to expose to the host.
1787 This enables support for exposing (e)MMC devices via DFU.
1790 This enables support for exposing NAND devices via DFU.
1793 This enables support for exposing RAM via DFU.
1794 Note: DFU spec refer to non-volatile memory usage, but
1795 allow usages beyond the scope of spec - here RAM usage,
1796 one that would help mostly the developer.
1798 CONFIG_SYS_DFU_DATA_BUF_SIZE
1799 Dfu transfer uses a buffer before writing data to the
1800 raw storage device. Make the size (in bytes) of this buffer
1801 configurable. The size of this buffer is also configurable
1802 through the "dfu_bufsiz" environment variable.
1804 CONFIG_SYS_DFU_MAX_FILE_SIZE
1805 When updating files rather than the raw storage device,
1806 we use a static buffer to copy the file into and then write
1807 the buffer once we've been given the whole file. Define
1808 this to the maximum filesize (in bytes) for the buffer.
1809 Default is 4 MiB if undefined.
1811 DFU_DEFAULT_POLL_TIMEOUT
1812 Poll timeout [ms], is the timeout a device can send to the
1813 host. The host must wait for this timeout before sending
1814 a subsequent DFU_GET_STATUS request to the device.
1816 DFU_MANIFEST_POLL_TIMEOUT
1817 Poll timeout [ms], which the device sends to the host when
1818 entering dfuMANIFEST state. Host waits this timeout, before
1819 sending again an USB request to the device.
1821 - USB Device Android Fastboot support:
1823 This enables the command "fastboot" which enables the Android
1824 fastboot mode for the platform's USB device. Fastboot is a USB
1825 protocol for downloading images, flashing and device control
1826 used on Android devices.
1827 See doc/README.android-fastboot for more information.
1829 CONFIG_ANDROID_BOOT_IMAGE
1830 This enables support for booting images which use the Android
1831 image format header.
1833 CONFIG_USB_FASTBOOT_BUF_ADDR
1834 The fastboot protocol requires a large memory buffer for
1835 downloads. Define this to the starting RAM address to use for
1838 CONFIG_USB_FASTBOOT_BUF_SIZE
1839 The fastboot protocol requires a large memory buffer for
1840 downloads. This buffer should be as large as possible for a
1841 platform. Define this to the size available RAM for fastboot.
1843 CONFIG_FASTBOOT_FLASH
1844 The fastboot protocol includes a "flash" command for writing
1845 the downloaded image to a non-volatile storage device. Define
1846 this to enable the "fastboot flash" command.
1848 CONFIG_FASTBOOT_FLASH_MMC_DEV
1849 The fastboot "flash" command requires additional information
1850 regarding the non-volatile storage device. Define this to
1851 the eMMC device that fastboot should use to store the image.
1853 CONFIG_FASTBOOT_GPT_NAME
1854 The fastboot "flash" command supports writing the downloaded
1855 image to the Protective MBR and the Primary GUID Partition
1856 Table. (Additionally, this downloaded image is post-processed
1857 to generate and write the Backup GUID Partition Table.)
1858 This occurs when the specified "partition name" on the
1859 "fastboot flash" command line matches this value.
1860 Default is GPT_ENTRY_NAME (currently "gpt") if undefined.
1862 - Journaling Flash filesystem support:
1863 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1864 CONFIG_JFFS2_NAND_DEV
1865 Define these for a default partition on a NAND device
1867 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1868 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1869 Define these for a default partition on a NOR device
1871 CONFIG_SYS_JFFS_CUSTOM_PART
1872 Define this to create an own partition. You have to provide a
1873 function struct part_info* jffs2_part_info(int part_num)
1875 If you define only one JFFS2 partition you may also want to
1876 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1877 to disable the command chpart. This is the default when you
1878 have not defined a custom partition
1880 - FAT(File Allocation Table) filesystem write function support:
1883 Define this to enable support for saving memory data as a
1884 file in FAT formatted partition.
1886 This will also enable the command "fatwrite" enabling the
1887 user to write files to FAT.
1889 CBFS (Coreboot Filesystem) support
1892 Define this to enable support for reading from a Coreboot
1893 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1896 - FAT(File Allocation Table) filesystem cluster size:
1897 CONFIG_FS_FAT_MAX_CLUSTSIZE
1899 Define the max cluster size for fat operations else
1900 a default value of 65536 will be defined.
1905 Define this to enable standard (PC-Style) keyboard
1909 Standard PC keyboard driver with US (is default) and
1910 GERMAN key layout (switch via environment 'keymap=de') support.
1911 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1912 for cfb_console. Supports cursor blinking.
1915 Enables a Chrome OS keyboard using the CROS_EC interface.
1916 This uses CROS_EC to communicate with a second microcontroller
1917 which provides key scans on request.
1922 Define this to enable video support (for output to
1925 CONFIG_VIDEO_CT69000
1927 Enable Chips & Technologies 69000 Video chip
1929 CONFIG_VIDEO_SMI_LYNXEM
1930 Enable Silicon Motion SMI 712/710/810 Video chip. The
1931 video output is selected via environment 'videoout'
1932 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1935 For the CT69000 and SMI_LYNXEM drivers, videomode is
1936 selected via environment 'videomode'. Two different ways
1938 - "videomode=num" 'num' is a standard LiLo mode numbers.
1939 Following standard modes are supported (* is default):
1941 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1942 -------------+---------------------------------------------
1943 8 bits | 0x301* 0x303 0x305 0x161 0x307
1944 15 bits | 0x310 0x313 0x316 0x162 0x319
1945 16 bits | 0x311 0x314 0x317 0x163 0x31A
1946 24 bits | 0x312 0x315 0x318 ? 0x31B
1947 -------------+---------------------------------------------
1948 (i.e. setenv videomode 317; saveenv; reset;)
1950 - "videomode=bootargs" all the video parameters are parsed
1951 from the bootargs. (See drivers/video/videomodes.c)
1954 CONFIG_VIDEO_SED13806
1955 Enable Epson SED13806 driver. This driver supports 8bpp
1956 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1957 or CONFIG_VIDEO_SED13806_16BPP
1960 Enable the Freescale DIU video driver. Reference boards for
1961 SOCs that have a DIU should define this macro to enable DIU
1962 support, and should also define these other macros:
1968 CONFIG_VIDEO_SW_CURSOR
1969 CONFIG_VGA_AS_SINGLE_DEVICE
1971 CONFIG_VIDEO_BMP_LOGO
1973 The DIU driver will look for the 'video-mode' environment
1974 variable, and if defined, enable the DIU as a console during
1975 boot. See the documentation file README.video for a
1976 description of this variable.
1980 Enable the VGA video / BIOS for x86. The alternative if you
1981 are using coreboot is to use the coreboot frame buffer
1988 Define this to enable a custom keyboard support.
1989 This simply calls drv_keyboard_init() which must be
1990 defined in your board-specific files.
1991 The only board using this so far is RBC823.
1993 - LCD Support: CONFIG_LCD
1995 Define this to enable LCD support (for output to LCD
1996 display); also select one of the supported displays
1997 by defining one of these:
2001 HITACHI TX09D70VM1CCA, 3.5", 240x320.
2003 CONFIG_NEC_NL6448AC33:
2005 NEC NL6448AC33-18. Active, color, single scan.
2007 CONFIG_NEC_NL6448BC20
2009 NEC NL6448BC20-08. 6.5", 640x480.
2010 Active, color, single scan.
2012 CONFIG_NEC_NL6448BC33_54
2014 NEC NL6448BC33-54. 10.4", 640x480.
2015 Active, color, single scan.
2019 Sharp 320x240. Active, color, single scan.
2020 It isn't 16x9, and I am not sure what it is.
2022 CONFIG_SHARP_LQ64D341
2024 Sharp LQ64D341 display, 640x480.
2025 Active, color, single scan.
2029 HLD1045 display, 640x480.
2030 Active, color, single scan.
2034 Optrex CBL50840-2 NF-FW 99 22 M5
2036 Hitachi LMG6912RPFC-00T
2040 320x240. Black & white.
2042 Normally display is black on white background; define
2043 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
2045 CONFIG_LCD_ALIGNMENT
2047 Normally the LCD is page-aligned (typically 4KB). If this is
2048 defined then the LCD will be aligned to this value instead.
2049 For ARM it is sometimes useful to use MMU_SECTION_SIZE
2050 here, since it is cheaper to change data cache settings on
2051 a per-section basis.
2053 CONFIG_CONSOLE_SCROLL_LINES
2055 When the console need to be scrolled, this is the number of
2056 lines to scroll by. It defaults to 1. Increasing this makes
2057 the console jump but can help speed up operation when scrolling
2062 Support drawing of RLE8-compressed bitmaps on the LCD.
2066 Enables an 'i2c edid' command which can read EDID
2067 information over I2C from an attached LCD display.
2069 - Splash Screen Support: CONFIG_SPLASH_SCREEN
2071 If this option is set, the environment is checked for
2072 a variable "splashimage". If found, the usual display
2073 of logo, copyright and system information on the LCD
2074 is suppressed and the BMP image at the address
2075 specified in "splashimage" is loaded instead. The
2076 console is redirected to the "nulldev", too. This
2077 allows for a "silent" boot where a splash screen is
2078 loaded very quickly after power-on.
2080 CONFIG_SPLASHIMAGE_GUARD
2082 If this option is set, then U-Boot will prevent the environment
2083 variable "splashimage" from being set to a problematic address
2084 (see README.displaying-bmps).
2085 This option is useful for targets where, due to alignment
2086 restrictions, an improperly aligned BMP image will cause a data
2087 abort. If you think you will not have problems with unaligned
2088 accesses (for example because your toolchain prevents them)
2089 there is no need to set this option.
2091 CONFIG_SPLASH_SCREEN_ALIGN
2093 If this option is set the splash image can be freely positioned
2094 on the screen. Environment variable "splashpos" specifies the
2095 position as "x,y". If a positive number is given it is used as
2096 number of pixel from left/top. If a negative number is given it
2097 is used as number of pixel from right/bottom. You can also
2098 specify 'm' for centering the image.
2101 setenv splashpos m,m
2102 => image at center of screen
2104 setenv splashpos 30,20
2105 => image at x = 30 and y = 20
2107 setenv splashpos -10,m
2108 => vertically centered image
2109 at x = dspWidth - bmpWidth - 9
2111 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
2113 If this option is set, additionally to standard BMP
2114 images, gzipped BMP images can be displayed via the
2115 splashscreen support or the bmp command.
2117 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
2119 If this option is set, 8-bit RLE compressed BMP images
2120 can be displayed via the splashscreen support or the
2123 - Do compressing for memory range:
2126 If this option is set, it would use zlib deflate method
2127 to compress the specified memory at its best effort.
2129 - Compression support:
2132 Enabled by default to support gzip compressed images.
2136 If this option is set, support for bzip2 compressed
2137 images is included. If not, only uncompressed and gzip
2138 compressed images are supported.
2140 NOTE: the bzip2 algorithm requires a lot of RAM, so
2141 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
2146 If this option is set, support for lzma compressed
2149 Note: The LZMA algorithm adds between 2 and 4KB of code and it
2150 requires an amount of dynamic memory that is given by the
2153 (1846 + 768 << (lc + lp)) * sizeof(uint16)
2155 Where lc and lp stand for, respectively, Literal context bits
2156 and Literal pos bits.
2158 This value is upper-bounded by 14MB in the worst case. Anyway,
2159 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
2160 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
2161 a very small buffer.
2163 Use the lzmainfo tool to determinate the lc and lp values and
2164 then calculate the amount of needed dynamic memory (ensuring
2165 the appropriate CONFIG_SYS_MALLOC_LEN value).
2169 If this option is set, support for LZO compressed images
2175 The address of PHY on MII bus.
2177 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2179 The clock frequency of the MII bus
2183 If this option is set, support for speed/duplex
2184 detection of gigabit PHY is included.
2186 CONFIG_PHY_RESET_DELAY
2188 Some PHY like Intel LXT971A need extra delay after
2189 reset before any MII register access is possible.
2190 For such PHY, set this option to the usec delay
2191 required. (minimum 300usec for LXT971A)
2193 CONFIG_PHY_CMD_DELAY (ppc4xx)
2195 Some PHY like Intel LXT971A need extra delay after
2196 command issued before MII status register can be read
2206 Define a default value for Ethernet address to use
2207 for the respective Ethernet interface, in case this
2208 is not determined automatically.
2213 Define a default value for the IP address to use for
2214 the default Ethernet interface, in case this is not
2215 determined through e.g. bootp.
2216 (Environment variable "ipaddr")
2218 - Server IP address:
2221 Defines a default value for the IP address of a TFTP
2222 server to contact when using the "tftboot" command.
2223 (Environment variable "serverip")
2225 CONFIG_KEEP_SERVERADDR
2227 Keeps the server's MAC address, in the env 'serveraddr'
2228 for passing to bootargs (like Linux's netconsole option)
2230 - Gateway IP address:
2233 Defines a default value for the IP address of the
2234 default router where packets to other networks are
2236 (Environment variable "gatewayip")
2241 Defines a default value for the subnet mask (or
2242 routing prefix) which is used to determine if an IP
2243 address belongs to the local subnet or needs to be
2244 forwarded through a router.
2245 (Environment variable "netmask")
2247 - Multicast TFTP Mode:
2250 Defines whether you want to support multicast TFTP as per
2251 rfc-2090; for example to work with atftp. Lets lots of targets
2252 tftp down the same boot image concurrently. Note: the Ethernet
2253 driver in use must provide a function: mcast() to join/leave a
2256 - BOOTP Recovery Mode:
2257 CONFIG_BOOTP_RANDOM_DELAY
2259 If you have many targets in a network that try to
2260 boot using BOOTP, you may want to avoid that all
2261 systems send out BOOTP requests at precisely the same
2262 moment (which would happen for instance at recovery
2263 from a power failure, when all systems will try to
2264 boot, thus flooding the BOOTP server. Defining
2265 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2266 inserted before sending out BOOTP requests. The
2267 following delays are inserted then:
2269 1st BOOTP request: delay 0 ... 1 sec
2270 2nd BOOTP request: delay 0 ... 2 sec
2271 3rd BOOTP request: delay 0 ... 4 sec
2273 BOOTP requests: delay 0 ... 8 sec
2275 CONFIG_BOOTP_ID_CACHE_SIZE
2277 BOOTP packets are uniquely identified using a 32-bit ID. The
2278 server will copy the ID from client requests to responses and
2279 U-Boot will use this to determine if it is the destination of
2280 an incoming response. Some servers will check that addresses
2281 aren't in use before handing them out (usually using an ARP
2282 ping) and therefore take up to a few hundred milliseconds to
2283 respond. Network congestion may also influence the time it
2284 takes for a response to make it back to the client. If that
2285 time is too long, U-Boot will retransmit requests. In order
2286 to allow earlier responses to still be accepted after these
2287 retransmissions, U-Boot's BOOTP client keeps a small cache of
2288 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2289 cache. The default is to keep IDs for up to four outstanding
2290 requests. Increasing this will allow U-Boot to accept offers
2291 from a BOOTP client in networks with unusually high latency.
2293 - DHCP Advanced Options:
2294 You can fine tune the DHCP functionality by defining
2295 CONFIG_BOOTP_* symbols:
2297 CONFIG_BOOTP_SUBNETMASK
2298 CONFIG_BOOTP_GATEWAY
2299 CONFIG_BOOTP_HOSTNAME
2300 CONFIG_BOOTP_NISDOMAIN
2301 CONFIG_BOOTP_BOOTPATH
2302 CONFIG_BOOTP_BOOTFILESIZE
2305 CONFIG_BOOTP_SEND_HOSTNAME
2306 CONFIG_BOOTP_NTPSERVER
2307 CONFIG_BOOTP_TIMEOFFSET
2308 CONFIG_BOOTP_VENDOREX
2309 CONFIG_BOOTP_MAY_FAIL
2311 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2312 environment variable, not the BOOTP server.
2314 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2315 after the configured retry count, the call will fail
2316 instead of starting over. This can be used to fail over
2317 to Link-local IP address configuration if the DHCP server
2320 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2321 serverip from a DHCP server, it is possible that more
2322 than one DNS serverip is offered to the client.
2323 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2324 serverip will be stored in the additional environment
2325 variable "dnsip2". The first DNS serverip is always
2326 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2329 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2330 to do a dynamic update of a DNS server. To do this, they
2331 need the hostname of the DHCP requester.
2332 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2333 of the "hostname" environment variable is passed as
2334 option 12 to the DHCP server.
2336 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2338 A 32bit value in microseconds for a delay between
2339 receiving a "DHCP Offer" and sending the "DHCP Request".
2340 This fixes a problem with certain DHCP servers that don't
2341 respond 100% of the time to a "DHCP request". E.g. On an
2342 AT91RM9200 processor running at 180MHz, this delay needed
2343 to be *at least* 15,000 usec before a Windows Server 2003
2344 DHCP server would reply 100% of the time. I recommend at
2345 least 50,000 usec to be safe. The alternative is to hope
2346 that one of the retries will be successful but note that
2347 the DHCP timeout and retry process takes a longer than
2350 - Link-local IP address negotiation:
2351 Negotiate with other link-local clients on the local network
2352 for an address that doesn't require explicit configuration.
2353 This is especially useful if a DHCP server cannot be guaranteed
2354 to exist in all environments that the device must operate.
2356 See doc/README.link-local for more information.
2359 CONFIG_CDP_DEVICE_ID
2361 The device id used in CDP trigger frames.
2363 CONFIG_CDP_DEVICE_ID_PREFIX
2365 A two character string which is prefixed to the MAC address
2370 A printf format string which contains the ascii name of
2371 the port. Normally is set to "eth%d" which sets
2372 eth0 for the first Ethernet, eth1 for the second etc.
2374 CONFIG_CDP_CAPABILITIES
2376 A 32bit integer which indicates the device capabilities;
2377 0x00000010 for a normal host which does not forwards.
2381 An ascii string containing the version of the software.
2385 An ascii string containing the name of the platform.
2389 A 32bit integer sent on the trigger.
2391 CONFIG_CDP_POWER_CONSUMPTION
2393 A 16bit integer containing the power consumption of the
2394 device in .1 of milliwatts.
2396 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2398 A byte containing the id of the VLAN.
2400 - Status LED: CONFIG_STATUS_LED
2402 Several configurations allow to display the current
2403 status using a LED. For instance, the LED will blink
2404 fast while running U-Boot code, stop blinking as
2405 soon as a reply to a BOOTP request was received, and
2406 start blinking slow once the Linux kernel is running
2407 (supported by a status LED driver in the Linux
2408 kernel). Defining CONFIG_STATUS_LED enables this
2414 The status LED can be connected to a GPIO pin.
2415 In such cases, the gpio_led driver can be used as a
2416 status LED backend implementation. Define CONFIG_GPIO_LED
2417 to include the gpio_led driver in the U-Boot binary.
2419 CONFIG_GPIO_LED_INVERTED_TABLE
2420 Some GPIO connected LEDs may have inverted polarity in which
2421 case the GPIO high value corresponds to LED off state and
2422 GPIO low value corresponds to LED on state.
2423 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2424 with a list of GPIO LEDs that have inverted polarity.
2426 - CAN Support: CONFIG_CAN_DRIVER
2428 Defining CONFIG_CAN_DRIVER enables CAN driver support
2429 on those systems that support this (optional)
2430 feature, like the TQM8xxL modules.
2432 - I2C Support: CONFIG_SYS_I2C
2434 This enable the NEW i2c subsystem, and will allow you to use
2435 i2c commands at the u-boot command line (as long as you set
2436 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2437 based realtime clock chips or other i2c devices. See
2438 common/cmd_i2c.c for a description of the command line
2441 ported i2c driver to the new framework:
2442 - drivers/i2c/soft_i2c.c:
2443 - activate first bus with CONFIG_SYS_I2C_SOFT define
2444 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2445 for defining speed and slave address
2446 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2447 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2448 for defining speed and slave address
2449 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2450 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2451 for defining speed and slave address
2452 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2453 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2454 for defining speed and slave address
2456 - drivers/i2c/fsl_i2c.c:
2457 - activate i2c driver with CONFIG_SYS_I2C_FSL
2458 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2459 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2460 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2462 - If your board supports a second fsl i2c bus, define
2463 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2464 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2465 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2468 - drivers/i2c/tegra_i2c.c:
2469 - activate this driver with CONFIG_SYS_I2C_TEGRA
2470 - This driver adds 4 i2c buses with a fix speed from
2471 100000 and the slave addr 0!
2473 - drivers/i2c/ppc4xx_i2c.c
2474 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2475 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2476 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2478 - drivers/i2c/i2c_mxc.c
2479 - activate this driver with CONFIG_SYS_I2C_MXC
2480 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2481 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2482 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2483 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2484 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2485 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2486 If those defines are not set, default value is 100000
2487 for speed, and 0 for slave.
2489 - drivers/i2c/rcar_i2c.c:
2490 - activate this driver with CONFIG_SYS_I2C_RCAR
2491 - This driver adds 4 i2c buses
2493 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2494 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2495 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2496 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2497 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2498 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2499 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2500 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2501 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2503 - drivers/i2c/sh_i2c.c:
2504 - activate this driver with CONFIG_SYS_I2C_SH
2505 - This driver adds from 2 to 5 i2c buses
2507 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2508 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2509 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2510 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2511 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2512 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2513 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2514 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2515 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2516 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2517 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2518 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2519 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2521 - drivers/i2c/omap24xx_i2c.c
2522 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2523 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2524 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2525 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2526 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2527 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2528 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2529 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2530 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2531 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2532 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2534 - drivers/i2c/zynq_i2c.c
2535 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2536 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2537 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2539 - drivers/i2c/s3c24x0_i2c.c:
2540 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2541 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2542 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2543 with a fix speed from 100000 and the slave addr 0!
2545 - drivers/i2c/ihs_i2c.c
2546 - activate this driver with CONFIG_SYS_I2C_IHS
2547 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2548 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2549 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2550 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2551 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2552 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2553 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2554 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2555 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2556 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2557 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2558 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2562 CONFIG_SYS_NUM_I2C_BUSES
2563 Hold the number of i2c buses you want to use. If you
2564 don't use/have i2c muxes on your i2c bus, this
2565 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2568 CONFIG_SYS_I2C_DIRECT_BUS
2569 define this, if you don't use i2c muxes on your hardware.
2570 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2573 CONFIG_SYS_I2C_MAX_HOPS
2574 define how many muxes are maximal consecutively connected
2575 on one i2c bus. If you not use i2c muxes, omit this
2578 CONFIG_SYS_I2C_BUSES
2579 hold a list of buses you want to use, only used if
2580 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2581 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2582 CONFIG_SYS_NUM_I2C_BUSES = 9:
2584 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2585 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2586 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2587 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2588 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2589 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2590 {1, {I2C_NULL_HOP}}, \
2591 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2592 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2596 bus 0 on adapter 0 without a mux
2597 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2598 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2599 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2600 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2601 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2602 bus 6 on adapter 1 without a mux
2603 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2604 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2606 If you do not have i2c muxes on your board, omit this define.
2608 - Legacy I2C Support: CONFIG_HARD_I2C
2610 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2611 provides the following compelling advantages:
2613 - more than one i2c adapter is usable
2614 - approved multibus support
2615 - better i2c mux support
2617 ** Please consider updating your I2C driver now. **
2619 These enable legacy I2C serial bus commands. Defining
2620 CONFIG_HARD_I2C will include the appropriate I2C driver
2621 for the selected CPU.
2623 This will allow you to use i2c commands at the u-boot
2624 command line (as long as you set CONFIG_CMD_I2C in
2625 CONFIG_COMMANDS) and communicate with i2c based realtime
2626 clock chips. See common/cmd_i2c.c for a description of the
2627 command line interface.
2629 CONFIG_HARD_I2C selects a hardware I2C controller.
2631 There are several other quantities that must also be
2632 defined when you define CONFIG_HARD_I2C.
2634 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2635 to be the frequency (in Hz) at which you wish your i2c bus
2636 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2637 the CPU's i2c node address).
2639 Now, the u-boot i2c code for the mpc8xx
2640 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2641 and so its address should therefore be cleared to 0 (See,
2642 eg, MPC823e User's Manual p.16-473). So, set
2643 CONFIG_SYS_I2C_SLAVE to 0.
2645 CONFIG_SYS_I2C_INIT_MPC5XXX
2647 When a board is reset during an i2c bus transfer
2648 chips might think that the current transfer is still
2649 in progress. Reset the slave devices by sending start
2650 commands until the slave device responds.
2652 That's all that's required for CONFIG_HARD_I2C.
2654 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2655 then the following macros need to be defined (examples are
2656 from include/configs/lwmon.h):
2660 (Optional). Any commands necessary to enable the I2C
2661 controller or configure ports.
2663 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2667 (Only for MPC8260 CPU). The I/O port to use (the code
2668 assumes both bits are on the same port). Valid values
2669 are 0..3 for ports A..D.
2673 The code necessary to make the I2C data line active
2674 (driven). If the data line is open collector, this
2677 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2681 The code necessary to make the I2C data line tri-stated
2682 (inactive). If the data line is open collector, this
2685 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2689 Code that returns true if the I2C data line is high,
2692 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2696 If <bit> is true, sets the I2C data line high. If it
2697 is false, it clears it (low).
2699 eg: #define I2C_SDA(bit) \
2700 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2701 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2705 If <bit> is true, sets the I2C clock line high. If it
2706 is false, it clears it (low).
2708 eg: #define I2C_SCL(bit) \
2709 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2710 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2714 This delay is invoked four times per clock cycle so this
2715 controls the rate of data transfer. The data rate thus
2716 is 1 / (I2C_DELAY * 4). Often defined to be something
2719 #define I2C_DELAY udelay(2)
2721 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2723 If your arch supports the generic GPIO framework (asm/gpio.h),
2724 then you may alternatively define the two GPIOs that are to be
2725 used as SCL / SDA. Any of the previous I2C_xxx macros will
2726 have GPIO-based defaults assigned to them as appropriate.
2728 You should define these to the GPIO value as given directly to
2729 the generic GPIO functions.
2731 CONFIG_SYS_I2C_INIT_BOARD
2733 When a board is reset during an i2c bus transfer
2734 chips might think that the current transfer is still
2735 in progress. On some boards it is possible to access
2736 the i2c SCLK line directly, either by using the
2737 processor pin as a GPIO or by having a second pin
2738 connected to the bus. If this option is defined a
2739 custom i2c_init_board() routine in boards/xxx/board.c
2740 is run early in the boot sequence.
2742 CONFIG_SYS_I2C_BOARD_LATE_INIT
2744 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2745 defined a custom i2c_board_late_init() routine in
2746 boards/xxx/board.c is run AFTER the operations in i2c_init()
2747 is completed. This callpoint can be used to unreset i2c bus
2748 using CPU i2c controller register accesses for CPUs whose i2c
2749 controller provide such a method. It is called at the end of
2750 i2c_init() to allow i2c_init operations to setup the i2c bus
2751 controller on the CPU (e.g. setting bus speed & slave address).
2753 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2755 This option enables configuration of bi_iic_fast[] flags
2756 in u-boot bd_info structure based on u-boot environment
2757 variable "i2cfast". (see also i2cfast)
2759 CONFIG_I2C_MULTI_BUS
2761 This option allows the use of multiple I2C buses, each of which
2762 must have a controller. At any point in time, only one bus is
2763 active. To switch to a different bus, use the 'i2c dev' command.
2764 Note that bus numbering is zero-based.
2766 CONFIG_SYS_I2C_NOPROBES
2768 This option specifies a list of I2C devices that will be skipped
2769 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2770 is set, specify a list of bus-device pairs. Otherwise, specify
2771 a 1D array of device addresses
2774 #undef CONFIG_I2C_MULTI_BUS
2775 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2777 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2779 #define CONFIG_I2C_MULTI_BUS
2780 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2782 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2784 CONFIG_SYS_SPD_BUS_NUM
2786 If defined, then this indicates the I2C bus number for DDR SPD.
2787 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2789 CONFIG_SYS_RTC_BUS_NUM
2791 If defined, then this indicates the I2C bus number for the RTC.
2792 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2794 CONFIG_SYS_DTT_BUS_NUM
2796 If defined, then this indicates the I2C bus number for the DTT.
2797 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2799 CONFIG_SYS_I2C_DTT_ADDR:
2801 If defined, specifies the I2C address of the DTT device.
2802 If not defined, then U-Boot uses predefined value for
2803 specified DTT device.
2805 CONFIG_SOFT_I2C_READ_REPEATED_START
2807 defining this will force the i2c_read() function in
2808 the soft_i2c driver to perform an I2C repeated start
2809 between writing the address pointer and reading the
2810 data. If this define is omitted the default behaviour
2811 of doing a stop-start sequence will be used. Most I2C
2812 devices can use either method, but some require one or
2815 - SPI Support: CONFIG_SPI
2817 Enables SPI driver (so far only tested with
2818 SPI EEPROM, also an instance works with Crystal A/D and
2819 D/As on the SACSng board)
2823 Enables the driver for SPI controller on SuperH. Currently
2824 only SH7757 is supported.
2828 Enables extended (16-bit) SPI EEPROM addressing.
2829 (symmetrical to CONFIG_I2C_X)
2833 Enables a software (bit-bang) SPI driver rather than
2834 using hardware support. This is a general purpose
2835 driver that only requires three general I/O port pins
2836 (two outputs, one input) to function. If this is
2837 defined, the board configuration must define several
2838 SPI configuration items (port pins to use, etc). For
2839 an example, see include/configs/sacsng.h.
2843 Enables a hardware SPI driver for general-purpose reads
2844 and writes. As with CONFIG_SOFT_SPI, the board configuration
2845 must define a list of chip-select function pointers.
2846 Currently supported on some MPC8xxx processors. For an
2847 example, see include/configs/mpc8349emds.h.
2851 Enables the driver for the SPI controllers on i.MX and MXC
2852 SoCs. Currently i.MX31/35/51 are supported.
2854 CONFIG_SYS_SPI_MXC_WAIT
2855 Timeout for waiting until spi transfer completed.
2856 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2858 - FPGA Support: CONFIG_FPGA
2860 Enables FPGA subsystem.
2862 CONFIG_FPGA_<vendor>
2864 Enables support for specific chip vendors.
2867 CONFIG_FPGA_<family>
2869 Enables support for FPGA family.
2870 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2874 Specify the number of FPGA devices to support.
2876 CONFIG_CMD_FPGA_LOADMK
2878 Enable support for fpga loadmk command
2880 CONFIG_CMD_FPGA_LOADP
2882 Enable support for fpga loadp command - load partial bitstream
2884 CONFIG_CMD_FPGA_LOADBP
2886 Enable support for fpga loadbp command - load partial bitstream
2889 CONFIG_SYS_FPGA_PROG_FEEDBACK
2891 Enable printing of hash marks during FPGA configuration.
2893 CONFIG_SYS_FPGA_CHECK_BUSY
2895 Enable checks on FPGA configuration interface busy
2896 status by the configuration function. This option
2897 will require a board or device specific function to
2902 If defined, a function that provides delays in the FPGA
2903 configuration driver.
2905 CONFIG_SYS_FPGA_CHECK_CTRLC
2906 Allow Control-C to interrupt FPGA configuration
2908 CONFIG_SYS_FPGA_CHECK_ERROR
2910 Check for configuration errors during FPGA bitfile
2911 loading. For example, abort during Virtex II
2912 configuration if the INIT_B line goes low (which
2913 indicated a CRC error).
2915 CONFIG_SYS_FPGA_WAIT_INIT
2917 Maximum time to wait for the INIT_B line to de-assert
2918 after PROB_B has been de-asserted during a Virtex II
2919 FPGA configuration sequence. The default time is 500
2922 CONFIG_SYS_FPGA_WAIT_BUSY
2924 Maximum time to wait for BUSY to de-assert during
2925 Virtex II FPGA configuration. The default is 5 ms.
2927 CONFIG_SYS_FPGA_WAIT_CONFIG
2929 Time to wait after FPGA configuration. The default is
2932 - Configuration Management:
2935 Some SoCs need special image types (e.g. U-Boot binary
2936 with a special header) as build targets. By defining
2937 CONFIG_BUILD_TARGET in the SoC / board header, this
2938 special image will be automatically built upon calling
2943 If defined, this string will be added to the U-Boot
2944 version information (U_BOOT_VERSION)
2946 - Vendor Parameter Protection:
2948 U-Boot considers the values of the environment
2949 variables "serial#" (Board Serial Number) and
2950 "ethaddr" (Ethernet Address) to be parameters that
2951 are set once by the board vendor / manufacturer, and
2952 protects these variables from casual modification by
2953 the user. Once set, these variables are read-only,
2954 and write or delete attempts are rejected. You can
2955 change this behaviour:
2957 If CONFIG_ENV_OVERWRITE is #defined in your config
2958 file, the write protection for vendor parameters is
2959 completely disabled. Anybody can change or delete
2962 Alternatively, if you #define _both_ CONFIG_ETHADDR
2963 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2964 Ethernet address is installed in the environment,
2965 which can be changed exactly ONCE by the user. [The
2966 serial# is unaffected by this, i. e. it remains
2969 The same can be accomplished in a more flexible way
2970 for any variable by configuring the type of access
2971 to allow for those variables in the ".flags" variable
2972 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2977 Define this variable to enable the reservation of
2978 "protected RAM", i. e. RAM which is not overwritten
2979 by U-Boot. Define CONFIG_PRAM to hold the number of
2980 kB you want to reserve for pRAM. You can overwrite
2981 this default value by defining an environment
2982 variable "pram" to the number of kB you want to
2983 reserve. Note that the board info structure will
2984 still show the full amount of RAM. If pRAM is
2985 reserved, a new environment variable "mem" will
2986 automatically be defined to hold the amount of
2987 remaining RAM in a form that can be passed as boot
2988 argument to Linux, for instance like that:
2990 setenv bootargs ... mem=\${mem}
2993 This way you can tell Linux not to use this memory,
2994 either, which results in a memory region that will
2995 not be affected by reboots.
2997 *WARNING* If your board configuration uses automatic
2998 detection of the RAM size, you must make sure that
2999 this memory test is non-destructive. So far, the
3000 following board configurations are known to be
3003 IVMS8, IVML24, SPD8xx, TQM8xxL,
3004 HERMES, IP860, RPXlite, LWMON,
3007 - Access to physical memory region (> 4GB)
3008 Some basic support is provided for operations on memory not
3009 normally accessible to U-Boot - e.g. some architectures
3010 support access to more than 4GB of memory on 32-bit
3011 machines using physical address extension or similar.
3012 Define CONFIG_PHYSMEM to access this basic support, which
3013 currently only supports clearing the memory.
3018 Define this variable to stop the system in case of a
3019 fatal error, so that you have to reset it manually.
3020 This is probably NOT a good idea for an embedded
3021 system where you want the system to reboot
3022 automatically as fast as possible, but it may be
3023 useful during development since you can try to debug
3024 the conditions that lead to the situation.
3026 CONFIG_NET_RETRY_COUNT
3028 This variable defines the number of retries for
3029 network operations like ARP, RARP, TFTP, or BOOTP
3030 before giving up the operation. If not defined, a
3031 default value of 5 is used.
3035 Timeout waiting for an ARP reply in milliseconds.
3039 Timeout in milliseconds used in NFS protocol.
3040 If you encounter "ERROR: Cannot umount" in nfs command,
3041 try longer timeout such as
3042 #define CONFIG_NFS_TIMEOUT 10000UL
3044 - Command Interpreter:
3045 CONFIG_AUTO_COMPLETE
3047 Enable auto completion of commands using TAB.
3049 CONFIG_SYS_PROMPT_HUSH_PS2
3051 This defines the secondary prompt string, which is
3052 printed when the command interpreter needs more input
3053 to complete a command. Usually "> ".
3057 In the current implementation, the local variables
3058 space and global environment variables space are
3059 separated. Local variables are those you define by
3060 simply typing `name=value'. To access a local
3061 variable later on, you have write `$name' or
3062 `${name}'; to execute the contents of a variable
3063 directly type `$name' at the command prompt.
3065 Global environment variables are those you use
3066 setenv/printenv to work with. To run a command stored
3067 in such a variable, you need to use the run command,
3068 and you must not use the '$' sign to access them.
3070 To store commands and special characters in a
3071 variable, please use double quotation marks
3072 surrounding the whole text of the variable, instead
3073 of the backslashes before semicolons and special
3076 - Command Line Editing and History:
3077 CONFIG_CMDLINE_EDITING
3079 Enable editing and History functions for interactive
3080 command line input operations
3082 - Default Environment:
3083 CONFIG_EXTRA_ENV_SETTINGS
3085 Define this to contain any number of null terminated
3086 strings (variable = value pairs) that will be part of
3087 the default environment compiled into the boot image.
3089 For example, place something like this in your
3090 board's config file:
3092 #define CONFIG_EXTRA_ENV_SETTINGS \
3096 Warning: This method is based on knowledge about the
3097 internal format how the environment is stored by the
3098 U-Boot code. This is NOT an official, exported
3099 interface! Although it is unlikely that this format
3100 will change soon, there is no guarantee either.
3101 You better know what you are doing here.
3103 Note: overly (ab)use of the default environment is
3104 discouraged. Make sure to check other ways to preset
3105 the environment like the "source" command or the
3108 CONFIG_ENV_VARS_UBOOT_CONFIG
3110 Define this in order to add variables describing the
3111 U-Boot build configuration to the default environment.
3112 These will be named arch, cpu, board, vendor, and soc.
3114 Enabling this option will cause the following to be defined:
3122 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
3124 Define this in order to add variables describing certain
3125 run-time determined information about the hardware to the
3126 environment. These will be named board_name, board_rev.
3128 CONFIG_DELAY_ENVIRONMENT
3130 Normally the environment is loaded when the board is
3131 initialised so that it is available to U-Boot. This inhibits
3132 that so that the environment is not available until
3133 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
3134 this is instead controlled by the value of
3135 /config/load-environment.
3137 - DataFlash Support:
3138 CONFIG_HAS_DATAFLASH
3140 Defining this option enables DataFlash features and
3141 allows to read/write in Dataflash via the standard
3144 - Serial Flash support
3147 Defining this option enables SPI flash commands
3148 'sf probe/read/write/erase/update'.
3150 Usage requires an initial 'probe' to define the serial
3151 flash parameters, followed by read/write/erase/update
3154 The following defaults may be provided by the platform
3155 to handle the common case when only a single serial
3156 flash is present on the system.
3158 CONFIG_SF_DEFAULT_BUS Bus identifier
3159 CONFIG_SF_DEFAULT_CS Chip-select
3160 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3161 CONFIG_SF_DEFAULT_SPEED in Hz
3165 Define this option to include a destructive SPI flash
3168 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
3170 Define this option to use the Bank addr/Extended addr
3171 support on SPI flashes which has size > 16Mbytes.
3173 CONFIG_SF_DUAL_FLASH Dual flash memories
3175 Define this option to use dual flash support where two flash
3176 memories can be connected with a given cs line.
3177 Currently Xilinx Zynq qspi supports these type of connections.
3179 CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
3180 enable the W#/Vpp signal to disable writing to the status
3181 register on ST MICRON flashes like the N25Q128.
3182 The status register write enable/disable bit, combined with
3183 the W#/VPP signal provides hardware data protection for the
3184 device as follows: When the enable/disable bit is set to 1,
3185 and the W#/VPP signal is driven LOW, the status register
3186 nonvolatile bits become read-only and the WRITE STATUS REGISTER
3187 operation will not execute. The only way to exit this
3188 hardware-protected mode is to drive W#/VPP HIGH.
3190 - SystemACE Support:
3193 Adding this option adds support for Xilinx SystemACE
3194 chips attached via some sort of local bus. The address
3195 of the chip must also be defined in the
3196 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3198 #define CONFIG_SYSTEMACE
3199 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3201 When SystemACE support is added, the "ace" device type
3202 becomes available to the fat commands, i.e. fatls.
3204 - TFTP Fixed UDP Port:
3207 If this is defined, the environment variable tftpsrcp
3208 is used to supply the TFTP UDP source port value.
3209 If tftpsrcp isn't defined, the normal pseudo-random port
3210 number generator is used.
3212 Also, the environment variable tftpdstp is used to supply
3213 the TFTP UDP destination port value. If tftpdstp isn't
3214 defined, the normal port 69 is used.
3216 The purpose for tftpsrcp is to allow a TFTP server to
3217 blindly start the TFTP transfer using the pre-configured
3218 target IP address and UDP port. This has the effect of
3219 "punching through" the (Windows XP) firewall, allowing
3220 the remainder of the TFTP transfer to proceed normally.
3221 A better solution is to properly configure the firewall,
3222 but sometimes that is not allowed.
3227 This enables a generic 'hash' command which can produce
3228 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3232 Enable the hash verify command (hash -v). This adds to code
3235 CONFIG_SHA1 - This option enables support of hashing using SHA1
3236 algorithm. The hash is calculated in software.
3237 CONFIG_SHA256 - This option enables support of hashing using
3238 SHA256 algorithm. The hash is calculated in software.
3239 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3240 for SHA1/SHA256 hashing.
3241 This affects the 'hash' command and also the
3242 hash_lookup_algo() function.
3243 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3244 hardware-acceleration for SHA1/SHA256 progressive hashing.
3245 Data can be streamed in a block at a time and the hashing
3246 is performed in hardware.
3248 Note: There is also a sha1sum command, which should perhaps
3249 be deprecated in favour of 'hash sha1'.
3251 - Freescale i.MX specific commands:
3252 CONFIG_CMD_HDMIDETECT
3253 This enables 'hdmidet' command which returns true if an
3254 HDMI monitor is detected. This command is i.MX 6 specific.
3257 This enables the 'bmode' (bootmode) command for forcing
3258 a boot from specific media.
3260 This is useful for forcing the ROM's usb downloader to
3261 activate upon a watchdog reset which is nice when iterating
3262 on U-Boot. Using the reset button or running bmode normal
3263 will set it back to normal. This command currently
3264 supports i.MX53 and i.MX6.
3269 This enables the RSA algorithm used for FIT image verification
3270 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3272 The Modular Exponentiation algorithm in RSA is implemented using
3273 driver model. So CONFIG_DM needs to be enabled by default for this
3274 library to function.
3276 The signing part is build into mkimage regardless of this
3277 option. The software based modular exponentiation is built into
3278 mkimage irrespective of this option.
3280 - bootcount support:
3281 CONFIG_BOOTCOUNT_LIMIT
3283 This enables the bootcounter support, see:
3284 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3287 enable special bootcounter support on at91sam9xe based boards.
3289 enable special bootcounter support on blackfin based boards.
3291 enable special bootcounter support on da850 based boards.
3292 CONFIG_BOOTCOUNT_RAM
3293 enable support for the bootcounter in RAM
3294 CONFIG_BOOTCOUNT_I2C
3295 enable support for the bootcounter on an i2c (like RTC) device.
3296 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3297 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3299 CONFIG_BOOTCOUNT_ALEN = address len
3301 - Show boot progress:
3302 CONFIG_SHOW_BOOT_PROGRESS
3304 Defining this option allows to add some board-
3305 specific code (calling a user-provided function
3306 "show_boot_progress(int)") that enables you to show
3307 the system's boot progress on some display (for
3308 example, some LED's) on your board. At the moment,
3309 the following checkpoints are implemented:
3311 - Detailed boot stage timing
3313 Define this option to get detailed timing of each stage
3314 of the boot process.
3316 CONFIG_BOOTSTAGE_USER_COUNT
3317 This is the number of available user bootstage records.
3318 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3319 a new ID will be allocated from this stash. If you exceed
3320 the limit, recording will stop.
3322 CONFIG_BOOTSTAGE_REPORT
3323 Define this to print a report before boot, similar to this:
3325 Timer summary in microseconds:
3328 3,575,678 3,575,678 board_init_f start
3329 3,575,695 17 arch_cpu_init A9
3330 3,575,777 82 arch_cpu_init done
3331 3,659,598 83,821 board_init_r start
3332 3,910,375 250,777 main_loop
3333 29,916,167 26,005,792 bootm_start
3334 30,361,327 445,160 start_kernel
3336 CONFIG_CMD_BOOTSTAGE
3337 Add a 'bootstage' command which supports printing a report
3338 and un/stashing of bootstage data.
3340 CONFIG_BOOTSTAGE_FDT
3341 Stash the bootstage information in the FDT. A root 'bootstage'
3342 node is created with each bootstage id as a child. Each child
3343 has a 'name' property and either 'mark' containing the
3344 mark time in microsecond, or 'accum' containing the
3345 accumulated time for that bootstage id in microseconds.
3350 name = "board_init_f";
3359 Code in the Linux kernel can find this in /proc/devicetree.
3361 Legacy uImage format:
3364 1 common/cmd_bootm.c before attempting to boot an image
3365 -1 common/cmd_bootm.c Image header has bad magic number
3366 2 common/cmd_bootm.c Image header has correct magic number
3367 -2 common/cmd_bootm.c Image header has bad checksum
3368 3 common/cmd_bootm.c Image header has correct checksum
3369 -3 common/cmd_bootm.c Image data has bad checksum
3370 4 common/cmd_bootm.c Image data has correct checksum
3371 -4 common/cmd_bootm.c Image is for unsupported architecture
3372 5 common/cmd_bootm.c Architecture check OK
3373 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3374 6 common/cmd_bootm.c Image Type check OK
3375 -6 common/cmd_bootm.c gunzip uncompression error
3376 -7 common/cmd_bootm.c Unimplemented compression type
3377 7 common/cmd_bootm.c Uncompression OK
3378 8 common/cmd_bootm.c No uncompress/copy overwrite error
3379 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3381 9 common/image.c Start initial ramdisk verification
3382 -10 common/image.c Ramdisk header has bad magic number
3383 -11 common/image.c Ramdisk header has bad checksum
3384 10 common/image.c Ramdisk header is OK
3385 -12 common/image.c Ramdisk data has bad checksum
3386 11 common/image.c Ramdisk data has correct checksum
3387 12 common/image.c Ramdisk verification complete, start loading
3388 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3389 13 common/image.c Start multifile image verification
3390 14 common/image.c No initial ramdisk, no multifile, continue.
3392 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3394 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3395 -31 post/post.c POST test failed, detected by post_output_backlog()
3396 -32 post/post.c POST test failed, detected by post_run_single()
3398 34 common/cmd_doc.c before loading a Image from a DOC device
3399 -35 common/cmd_doc.c Bad usage of "doc" command
3400 35 common/cmd_doc.c correct usage of "doc" command
3401 -36 common/cmd_doc.c No boot device
3402 36 common/cmd_doc.c correct boot device
3403 -37 common/cmd_doc.c Unknown Chip ID on boot device
3404 37 common/cmd_doc.c correct chip ID found, device available
3405 -38 common/cmd_doc.c Read Error on boot device
3406 38 common/cmd_doc.c reading Image header from DOC device OK
3407 -39 common/cmd_doc.c Image header has bad magic number
3408 39 common/cmd_doc.c Image header has correct magic number
3409 -40 common/cmd_doc.c Error reading Image from DOC device
3410 40 common/cmd_doc.c Image header has correct magic number
3411 41 common/cmd_ide.c before loading a Image from a IDE device
3412 -42 common/cmd_ide.c Bad usage of "ide" command
3413 42 common/cmd_ide.c correct usage of "ide" command
3414 -43 common/cmd_ide.c No boot device
3415 43 common/cmd_ide.c boot device found
3416 -44 common/cmd_ide.c Device not available
3417 44 common/cmd_ide.c Device available
3418 -45 common/cmd_ide.c wrong partition selected
3419 45 common/cmd_ide.c partition selected
3420 -46 common/cmd_ide.c Unknown partition table
3421 46 common/cmd_ide.c valid partition table found
3422 -47 common/cmd_ide.c Invalid partition type
3423 47 common/cmd_ide.c correct partition type
3424 -48 common/cmd_ide.c Error reading Image Header on boot device
3425 48 common/cmd_ide.c reading Image Header from IDE device OK
3426 -49 common/cmd_ide.c Image header has bad magic number
3427 49 common/cmd_ide.c Image header has correct magic number
3428 -50 common/cmd_ide.c Image header has bad checksum
3429 50 common/cmd_ide.c Image header has correct checksum
3430 -51 common/cmd_ide.c Error reading Image from IDE device
3431 51 common/cmd_ide.c reading Image from IDE device OK
3432 52 common/cmd_nand.c before loading a Image from a NAND device
3433 -53 common/cmd_nand.c Bad usage of "nand" command
3434 53 common/cmd_nand.c correct usage of "nand" command
3435 -54 common/cmd_nand.c No boot device
3436 54 common/cmd_nand.c boot device found
3437 -55 common/cmd_nand.c Unknown Chip ID on boot device
3438 55 common/cmd_nand.c correct chip ID found, device available
3439 -56 common/cmd_nand.c Error reading Image Header on boot device
3440 56 common/cmd_nand.c reading Image Header from NAND device OK
3441 -57 common/cmd_nand.c Image header has bad magic number
3442 57 common/cmd_nand.c Image header has correct magic number
3443 -58 common/cmd_nand.c Error reading Image from NAND device
3444 58 common/cmd_nand.c reading Image from NAND device OK
3446 -60 common/env_common.c Environment has a bad CRC, using default
3448 64 net/eth.c starting with Ethernet configuration.
3449 -64 net/eth.c no Ethernet found.
3450 65 net/eth.c Ethernet found.
3452 -80 common/cmd_net.c usage wrong
3453 80 common/cmd_net.c before calling NetLoop()
3454 -81 common/cmd_net.c some error in NetLoop() occurred
3455 81 common/cmd_net.c NetLoop() back without error
3456 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3457 82 common/cmd_net.c trying automatic boot
3458 83 common/cmd_net.c running "source" command
3459 -83 common/cmd_net.c some error in automatic boot or "source" command
3460 84 common/cmd_net.c end without errors
3465 100 common/cmd_bootm.c Kernel FIT Image has correct format
3466 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3467 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3468 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3469 102 common/cmd_bootm.c Kernel unit name specified
3470 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3471 103 common/cmd_bootm.c Found configuration node
3472 104 common/cmd_bootm.c Got kernel subimage node offset
3473 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3474 105 common/cmd_bootm.c Kernel subimage hash verification OK
3475 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3476 106 common/cmd_bootm.c Architecture check OK
3477 -106 common/cmd_bootm.c Kernel subimage has wrong type
3478 107 common/cmd_bootm.c Kernel subimage type OK
3479 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3480 108 common/cmd_bootm.c Got kernel subimage data/size
3481 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3482 -109 common/cmd_bootm.c Can't get kernel subimage type
3483 -110 common/cmd_bootm.c Can't get kernel subimage comp
3484 -111 common/cmd_bootm.c Can't get kernel subimage os
3485 -112 common/cmd_bootm.c Can't get kernel subimage load address
3486 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3488 120 common/image.c Start initial ramdisk verification
3489 -120 common/image.c Ramdisk FIT image has incorrect format
3490 121 common/image.c Ramdisk FIT image has correct format
3491 122 common/image.c No ramdisk subimage unit name, using configuration
3492 -122 common/image.c Can't get configuration for ramdisk subimage
3493 123 common/image.c Ramdisk unit name specified
3494 -124 common/image.c Can't get ramdisk subimage node offset
3495 125 common/image.c Got ramdisk subimage node offset
3496 -125 common/image.c Ramdisk subimage hash verification failed
3497 126 common/image.c Ramdisk subimage hash verification OK
3498 -126 common/image.c Ramdisk subimage for unsupported architecture
3499 127 common/image.c Architecture check OK
3500 -127 common/image.c Can't get ramdisk subimage data/size
3501 128 common/image.c Got ramdisk subimage data/size
3502 129 common/image.c Can't get ramdisk load address
3503 -129 common/image.c Got ramdisk load address
3505 -130 common/cmd_doc.c Incorrect FIT image format
3506 131 common/cmd_doc.c FIT image format OK
3508 -140 common/cmd_ide.c Incorrect FIT image format
3509 141 common/cmd_ide.c FIT image format OK
3511 -150 common/cmd_nand.c Incorrect FIT image format
3512 151 common/cmd_nand.c FIT image format OK
3514 - legacy image format:
3515 CONFIG_IMAGE_FORMAT_LEGACY
3516 enables the legacy image format support in U-Boot.
3519 enabled if CONFIG_FIT_SIGNATURE is not defined.
3521 CONFIG_DISABLE_IMAGE_LEGACY
3522 disable the legacy image format
3524 This define is introduced, as the legacy image format is
3525 enabled per default for backward compatibility.
3527 - FIT image support:
3529 Enable support for the FIT uImage format.
3531 CONFIG_FIT_BEST_MATCH
3532 When no configuration is explicitly selected, default to the
3533 one whose fdt's compatibility field best matches that of
3534 U-Boot itself. A match is considered "best" if it matches the
3535 most specific compatibility entry of U-Boot's fdt's root node.
3536 The order of entries in the configuration's fdt is ignored.
3538 CONFIG_FIT_SIGNATURE
3539 This option enables signature verification of FIT uImages,
3540 using a hash signed and verified using RSA. If
3541 CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
3542 hashing is available using hardware, RSA library will use it.
3543 See doc/uImage.FIT/signature.txt for more details.
3545 WARNING: When relying on signed FIT images with required
3546 signature check the legacy image format is default
3547 disabled. If a board need legacy image format support
3548 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3550 CONFIG_FIT_DISABLE_SHA256
3551 Supporting SHA256 hashes has quite an impact on binary size.
3552 For constrained systems sha256 hash support can be disabled
3555 - Standalone program support:
3556 CONFIG_STANDALONE_LOAD_ADDR
3558 This option defines a board specific value for the
3559 address where standalone program gets loaded, thus
3560 overwriting the architecture dependent default
3563 - Frame Buffer Address:
3566 Define CONFIG_FB_ADDR if you want to use specific
3567 address for frame buffer. This is typically the case
3568 when using a graphics controller has separate video
3569 memory. U-Boot will then place the frame buffer at
3570 the given address instead of dynamically reserving it
3571 in system RAM by calling lcd_setmem(), which grabs
3572 the memory for the frame buffer depending on the
3573 configured panel size.
3575 Please see board_init_f function.
3577 - Automatic software updates via TFTP server
3579 CONFIG_UPDATE_TFTP_CNT_MAX
3580 CONFIG_UPDATE_TFTP_MSEC_MAX
3582 These options enable and control the auto-update feature;
3583 for a more detailed description refer to doc/README.update.
3585 - MTD Support (mtdparts command, UBI support)
3588 Adds the MTD device infrastructure from the Linux kernel.
3589 Needed for mtdparts command support.
3591 CONFIG_MTD_PARTITIONS
3593 Adds the MTD partitioning infrastructure from the Linux
3594 kernel. Needed for UBI support.
3596 CONFIG_MTD_NAND_VERIFY_WRITE
3597 verify if the written data is correct reread.
3602 Adds commands for interacting with MTD partitions formatted
3603 with the UBI flash translation layer
3605 Requires also defining CONFIG_RBTREE
3607 CONFIG_UBI_SILENCE_MSG
3609 Make the verbose messages from UBI stop printing. This leaves
3610 warnings and errors enabled.
3613 CONFIG_MTD_UBI_WL_THRESHOLD
3614 This parameter defines the maximum difference between the highest
3615 erase counter value and the lowest erase counter value of eraseblocks
3616 of UBI devices. When this threshold is exceeded, UBI starts performing
3617 wear leveling by means of moving data from eraseblock with low erase
3618 counter to eraseblocks with high erase counter.
3620 The default value should be OK for SLC NAND flashes, NOR flashes and
3621 other flashes which have eraseblock life-cycle 100000 or more.
3622 However, in case of MLC NAND flashes which typically have eraseblock
3623 life-cycle less than 10000, the threshold should be lessened (e.g.,
3624 to 128 or 256, although it does not have to be power of 2).
3628 CONFIG_MTD_UBI_BEB_LIMIT
3629 This option specifies the maximum bad physical eraseblocks UBI
3630 expects on the MTD device (per 1024 eraseblocks). If the
3631 underlying flash does not admit of bad eraseblocks (e.g. NOR
3632 flash), this value is ignored.
3634 NAND datasheets often specify the minimum and maximum NVM
3635 (Number of Valid Blocks) for the flashes' endurance lifetime.
3636 The maximum expected bad eraseblocks per 1024 eraseblocks
3637 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3638 which gives 20 for most NANDs (MaxNVB is basically the total
3639 count of eraseblocks on the chip).
3641 To put it differently, if this value is 20, UBI will try to
3642 reserve about 1.9% of physical eraseblocks for bad blocks
3643 handling. And that will be 1.9% of eraseblocks on the entire
3644 NAND chip, not just the MTD partition UBI attaches. This means
3645 that if you have, say, a NAND flash chip admits maximum 40 bad
3646 eraseblocks, and it is split on two MTD partitions of the same
3647 size, UBI will reserve 40 eraseblocks when attaching a
3652 CONFIG_MTD_UBI_FASTMAP
3653 Fastmap is a mechanism which allows attaching an UBI device
3654 in nearly constant time. Instead of scanning the whole MTD device it
3655 only has to locate a checkpoint (called fastmap) on the device.
3656 The on-flash fastmap contains all information needed to attach
3657 the device. Using fastmap makes only sense on large devices where
3658 attaching by scanning takes long. UBI will not automatically install
3659 a fastmap on old images, but you can set the UBI parameter
3660 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3661 that fastmap-enabled images are still usable with UBI implementations
3662 without fastmap support. On typical flash devices the whole fastmap
3663 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3665 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3666 Set this parameter to enable fastmap automatically on images
3673 Adds commands for interacting with UBI volumes formatted as
3674 UBIFS. UBIFS is read-only in u-boot.
3676 Requires UBI support as well as CONFIG_LZO
3678 CONFIG_UBIFS_SILENCE_MSG
3680 Make the verbose messages from UBIFS stop printing. This leaves
3681 warnings and errors enabled.
3685 Enable building of SPL globally.
3688 LDSCRIPT for linking the SPL binary.
3690 CONFIG_SPL_MAX_FOOTPRINT
3691 Maximum size in memory allocated to the SPL, BSS included.
3692 When defined, the linker checks that the actual memory
3693 used by SPL from _start to __bss_end does not exceed it.
3694 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3695 must not be both defined at the same time.
3698 Maximum size of the SPL image (text, data, rodata, and
3699 linker lists sections), BSS excluded.
3700 When defined, the linker checks that the actual size does
3703 CONFIG_SPL_TEXT_BASE
3704 TEXT_BASE for linking the SPL binary.
3706 CONFIG_SPL_RELOC_TEXT_BASE
3707 Address to relocate to. If unspecified, this is equal to
3708 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3710 CONFIG_SPL_BSS_START_ADDR
3711 Link address for the BSS within the SPL binary.
3713 CONFIG_SPL_BSS_MAX_SIZE
3714 Maximum size in memory allocated to the SPL BSS.
3715 When defined, the linker checks that the actual memory used
3716 by SPL from __bss_start to __bss_end does not exceed it.
3717 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3718 must not be both defined at the same time.
3721 Adress of the start of the stack SPL will use
3723 CONFIG_SPL_RELOC_STACK
3724 Adress of the start of the stack SPL will use after
3725 relocation. If unspecified, this is equal to
3728 CONFIG_SYS_SPL_MALLOC_START
3729 Starting address of the malloc pool used in SPL.
3731 CONFIG_SYS_SPL_MALLOC_SIZE
3732 The size of the malloc pool used in SPL.
3734 CONFIG_SPL_FRAMEWORK
3735 Enable the SPL framework under common/. This framework
3736 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3737 NAND loading of the Linux Kernel.
3740 Enable booting directly to an OS from SPL.
3741 See also: doc/README.falcon
3743 CONFIG_SPL_DISPLAY_PRINT
3744 For ARM, enable an optional function to print more information
3745 about the running system.
3747 CONFIG_SPL_INIT_MINIMAL
3748 Arch init code should be built for a very small image
3750 CONFIG_SPL_LIBCOMMON_SUPPORT
3751 Support for common/libcommon.o in SPL binary
3753 CONFIG_SPL_LIBDISK_SUPPORT
3754 Support for disk/libdisk.o in SPL binary
3756 CONFIG_SPL_I2C_SUPPORT
3757 Support for drivers/i2c/libi2c.o in SPL binary
3759 CONFIG_SPL_GPIO_SUPPORT
3760 Support for drivers/gpio/libgpio.o in SPL binary
3762 CONFIG_SPL_MMC_SUPPORT
3763 Support for drivers/mmc/libmmc.o in SPL binary
3765 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3766 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3767 Address and partition on the MMC to load U-Boot from
3768 when the MMC is being used in raw mode.
3770 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3771 Partition on the MMC to load U-Boot from when the MMC is being
3774 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3775 Sector to load kernel uImage from when MMC is being
3776 used in raw mode (for Falcon mode)
3778 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3779 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3780 Sector and number of sectors to load kernel argument
3781 parameters from when MMC is being used in raw mode
3784 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3785 Partition on the MMC to load U-Boot from when the MMC is being
3788 CONFIG_SPL_FAT_SUPPORT
3789 Support for fs/fat/libfat.o in SPL binary
3791 CONFIG_SPL_EXT_SUPPORT
3792 Support for EXT filesystem in SPL binary
3794 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3795 Filename to read to load U-Boot when reading from filesystem
3797 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3798 Filename to read to load kernel uImage when reading
3799 from filesystem (for Falcon mode)
3801 CONFIG_SPL_FS_LOAD_ARGS_NAME
3802 Filename to read to load kernel argument parameters
3803 when reading from filesystem (for Falcon mode)
3805 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3806 Set this for NAND SPL on PPC mpc83xx targets, so that
3807 start.S waits for the rest of the SPL to load before
3808 continuing (the hardware starts execution after just
3809 loading the first page rather than the full 4K).
3811 CONFIG_SPL_SKIP_RELOCATE
3812 Avoid SPL relocation
3814 CONFIG_SPL_NAND_BASE
3815 Include nand_base.c in the SPL. Requires
3816 CONFIG_SPL_NAND_DRIVERS.
3818 CONFIG_SPL_NAND_DRIVERS
3819 SPL uses normal NAND drivers, not minimal drivers.
3822 Include standard software ECC in the SPL
3824 CONFIG_SPL_NAND_SIMPLE
3825 Support for NAND boot using simple NAND drivers that
3826 expose the cmd_ctrl() interface.
3828 CONFIG_SPL_MTD_SUPPORT
3829 Support for the MTD subsystem within SPL. Useful for
3830 environment on NAND support within SPL.
3832 CONFIG_SPL_NAND_RAW_ONLY
3833 Support to boot only raw u-boot.bin images. Use this only
3834 if you need to save space.
3836 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3837 Set for the SPL on PPC mpc8xxx targets, support for
3838 drivers/ddr/fsl/libddr.o in SPL binary.
3840 CONFIG_SPL_COMMON_INIT_DDR
3841 Set for common ddr init with serial presence detect in
3844 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3845 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3846 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3847 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3848 CONFIG_SYS_NAND_ECCBYTES
3849 Defines the size and behavior of the NAND that SPL uses
3852 CONFIG_SPL_NAND_BOOT
3853 Add support NAND boot
3855 CONFIG_SYS_NAND_U_BOOT_OFFS
3856 Location in NAND to read U-Boot from
3858 CONFIG_SYS_NAND_U_BOOT_DST
3859 Location in memory to load U-Boot to
3861 CONFIG_SYS_NAND_U_BOOT_SIZE
3862 Size of image to load
3864 CONFIG_SYS_NAND_U_BOOT_START
3865 Entry point in loaded image to jump to
3867 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3868 Define this if you need to first read the OOB and then the
3869 data. This is used, for example, on davinci platforms.
3871 CONFIG_SPL_OMAP3_ID_NAND
3872 Support for an OMAP3-specific set of functions to return the
3873 ID and MFR of the first attached NAND chip, if present.
3875 CONFIG_SPL_SERIAL_SUPPORT
3876 Support for drivers/serial/libserial.o in SPL binary
3878 CONFIG_SPL_SPI_FLASH_SUPPORT
3879 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3881 CONFIG_SPL_SPI_SUPPORT
3882 Support for drivers/spi/libspi.o in SPL binary
3884 CONFIG_SPL_RAM_DEVICE
3885 Support for running image already present in ram, in SPL binary
3887 CONFIG_SPL_LIBGENERIC_SUPPORT
3888 Support for lib/libgeneric.o in SPL binary
3890 CONFIG_SPL_ENV_SUPPORT
3891 Support for the environment operating in SPL binary
3893 CONFIG_SPL_NET_SUPPORT
3894 Support for the net/libnet.o in SPL binary.
3895 It conflicts with SPL env from storage medium specified by
3896 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3899 Image offset to which the SPL should be padded before appending
3900 the SPL payload. By default, this is defined as
3901 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3902 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3903 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3906 Final target image containing SPL and payload. Some SPLs
3907 use an arch-specific makefile fragment instead, for
3908 example if more than one image needs to be produced.
3910 CONFIG_FIT_SPL_PRINT
3911 Printing information about a FIT image adds quite a bit of
3912 code to SPL. So this is normally disabled in SPL. Use this
3913 option to re-enable it. This will affect the output of the
3914 bootm command when booting a FIT image.
3918 Enable building of TPL globally.
3921 Image offset to which the TPL should be padded before appending
3922 the TPL payload. By default, this is defined as
3923 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3924 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3925 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3930 [so far only for SMDK2400 boards]
3932 - Modem support enable:
3933 CONFIG_MODEM_SUPPORT
3935 - RTS/CTS Flow control enable:
3938 - Modem debug support:
3939 CONFIG_MODEM_SUPPORT_DEBUG
3941 Enables debugging stuff (char screen[1024], dbg())
3942 for modem support. Useful only with BDI2000.
3944 - Interrupt support (PPC):
3946 There are common interrupt_init() and timer_interrupt()
3947 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3948 for CPU specific initialization. interrupt_init_cpu()
3949 should set decrementer_count to appropriate value. If
3950 CPU resets decrementer automatically after interrupt
3951 (ppc4xx) it should set decrementer_count to zero.
3952 timer_interrupt() calls timer_interrupt_cpu() for CPU
3953 specific handling. If board has watchdog / status_led
3954 / other_activity_monitor it works automatically from
3955 general timer_interrupt().
3959 In the target system modem support is enabled when a
3960 specific key (key combination) is pressed during
3961 power-on. Otherwise U-Boot will boot normally
3962 (autoboot). The key_pressed() function is called from
3963 board_init(). Currently key_pressed() is a dummy
3964 function, returning 1 and thus enabling modem
3967 If there are no modem init strings in the
3968 environment, U-Boot proceed to autoboot; the
3969 previous output (banner, info printfs) will be
3972 See also: doc/README.Modem
3974 Board initialization settings:
3975 ------------------------------
3977 During Initialization u-boot calls a number of board specific functions
3978 to allow the preparation of board specific prerequisites, e.g. pin setup
3979 before drivers are initialized. To enable these callbacks the
3980 following configuration macros have to be defined. Currently this is
3981 architecture specific, so please check arch/your_architecture/lib/board.c
3982 typically in board_init_f() and board_init_r().
3984 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3985 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3986 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3987 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3989 Configuration Settings:
3990 -----------------------
3992 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3993 Optionally it can be defined to support 64-bit memory commands.
3995 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3996 undefine this when you're short of memory.
3998 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3999 width of the commands listed in the 'help' command output.
4001 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
4002 prompt for user input.
4004 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
4006 - CONFIG_SYS_PBSIZE: Buffer size for Console output
4008 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
4010 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
4011 the application (usually a Linux kernel) when it is
4014 - CONFIG_SYS_BAUDRATE_TABLE:
4015 List of legal baudrate settings for this board.
4017 - CONFIG_SYS_CONSOLE_INFO_QUIET
4018 Suppress display of console information at boot.
4020 - CONFIG_SYS_CONSOLE_IS_IN_ENV
4021 If the board specific function
4022 extern int overwrite_console (void);
4023 returns 1, the stdin, stderr and stdout are switched to the
4024 serial port, else the settings in the environment are used.
4026 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
4027 Enable the call to overwrite_console().
4029 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
4030 Enable overwrite of previous console environment settings.
4032 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
4033 Begin and End addresses of the area used by the
4036 - CONFIG_SYS_ALT_MEMTEST:
4037 Enable an alternate, more extensive memory test.
4039 - CONFIG_SYS_MEMTEST_SCRATCH:
4040 Scratch address used by the alternate memory test
4041 You only need to set this if address zero isn't writeable
4043 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
4044 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
4045 this specified memory area will get subtracted from the top
4046 (end) of RAM and won't get "touched" at all by U-Boot. By
4047 fixing up gd->ram_size the Linux kernel should gets passed
4048 the now "corrected" memory size and won't touch it either.
4049 This should work for arch/ppc and arch/powerpc. Only Linux
4050 board ports in arch/powerpc with bootwrapper support that
4051 recalculate the memory size from the SDRAM controller setup
4052 will have to get fixed in Linux additionally.
4054 This option can be used as a workaround for the 440EPx/GRx
4055 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
4058 WARNING: Please make sure that this value is a multiple of
4059 the Linux page size (normally 4k). If this is not the case,
4060 then the end address of the Linux memory will be located at a
4061 non page size aligned address and this could cause major
4064 - CONFIG_SYS_LOADS_BAUD_CHANGE:
4065 Enable temporary baudrate change while serial download
4067 - CONFIG_SYS_SDRAM_BASE:
4068 Physical start address of SDRAM. _Must_ be 0 here.
4070 - CONFIG_SYS_MBIO_BASE:
4071 Physical start address of Motherboard I/O (if using a
4074 - CONFIG_SYS_FLASH_BASE:
4075 Physical start address of Flash memory.
4077 - CONFIG_SYS_MONITOR_BASE:
4078 Physical start address of boot monitor code (set by
4079 make config files to be same as the text base address
4080 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
4081 CONFIG_SYS_FLASH_BASE when booting from flash.
4083 - CONFIG_SYS_MONITOR_LEN:
4084 Size of memory reserved for monitor code, used to
4085 determine _at_compile_time_ (!) if the environment is
4086 embedded within the U-Boot image, or in a separate
4089 - CONFIG_SYS_MALLOC_LEN:
4090 Size of DRAM reserved for malloc() use.
4092 - CONFIG_SYS_MALLOC_F_LEN
4093 Size of the malloc() pool for use before relocation. If
4094 this is defined, then a very simple malloc() implementation
4095 will become available before relocation. The address is just
4096 below the global data, and the stack is moved down to make
4099 This feature allocates regions with increasing addresses
4100 within the region. calloc() is supported, but realloc()
4101 is not available. free() is supported but does nothing.
4102 The memory will be freed (or in fact just forgotten) when
4103 U-Boot relocates itself.
4105 Pre-relocation malloc() is only supported on ARM and sandbox
4106 at present but is fairly easy to enable for other archs.
4108 - CONFIG_SYS_MALLOC_SIMPLE
4109 Provides a simple and small malloc() and calloc() for those
4110 boards which do not use the full malloc in SPL (which is
4111 enabled with CONFIG_SYS_SPL_MALLOC_START).
4113 - CONFIG_SYS_NONCACHED_MEMORY:
4114 Size of non-cached memory area. This area of memory will be
4115 typically located right below the malloc() area and mapped
4116 uncached in the MMU. This is useful for drivers that would
4117 otherwise require a lot of explicit cache maintenance. For
4118 some drivers it's also impossible to properly maintain the
4119 cache. For example if the regions that need to be flushed
4120 are not a multiple of the cache-line size, *and* padding
4121 cannot be allocated between the regions to align them (i.e.
4122 if the HW requires a contiguous array of regions, and the
4123 size of each region is not cache-aligned), then a flush of
4124 one region may result in overwriting data that hardware has
4125 written to another region in the same cache-line. This can
4126 happen for example in network drivers where descriptors for
4127 buffers are typically smaller than the CPU cache-line (e.g.
4128 16 bytes vs. 32 or 64 bytes).
4130 Non-cached memory is only supported on 32-bit ARM at present.
4132 - CONFIG_SYS_BOOTM_LEN:
4133 Normally compressed uImages are limited to an
4134 uncompressed size of 8 MBytes. If this is not enough,
4135 you can define CONFIG_SYS_BOOTM_LEN in your board config file
4136 to adjust this setting to your needs.
4138 - CONFIG_SYS_BOOTMAPSZ:
4139 Maximum size of memory mapped by the startup code of
4140 the Linux kernel; all data that must be processed by
4141 the Linux kernel (bd_info, boot arguments, FDT blob if
4142 used) must be put below this limit, unless "bootm_low"
4143 environment variable is defined and non-zero. In such case
4144 all data for the Linux kernel must be between "bootm_low"
4145 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
4146 variable "bootm_mapsize" will override the value of
4147 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
4148 then the value in "bootm_size" will be used instead.
4150 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
4151 Enable initrd_high functionality. If defined then the
4152 initrd_high feature is enabled and the bootm ramdisk subcommand
4155 - CONFIG_SYS_BOOT_GET_CMDLINE:
4156 Enables allocating and saving kernel cmdline in space between
4157 "bootm_low" and "bootm_low" + BOOTMAPSZ.
4159 - CONFIG_SYS_BOOT_GET_KBD:
4160 Enables allocating and saving a kernel copy of the bd_info in
4161 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
4163 - CONFIG_SYS_MAX_FLASH_BANKS:
4164 Max number of Flash memory banks
4166 - CONFIG_SYS_MAX_FLASH_SECT:
4167 Max number of sectors on a Flash chip
4169 - CONFIG_SYS_FLASH_ERASE_TOUT:
4170 Timeout for Flash erase operations (in ms)
4172 - CONFIG_SYS_FLASH_WRITE_TOUT:
4173 Timeout for Flash write operations (in ms)
4175 - CONFIG_SYS_FLASH_LOCK_TOUT
4176 Timeout for Flash set sector lock bit operation (in ms)
4178 - CONFIG_SYS_FLASH_UNLOCK_TOUT
4179 Timeout for Flash clear lock bits operation (in ms)
4181 - CONFIG_SYS_FLASH_PROTECTION
4182 If defined, hardware flash sectors protection is used
4183 instead of U-Boot software protection.
4185 - CONFIG_SYS_DIRECT_FLASH_TFTP:
4187 Enable TFTP transfers directly to flash memory;
4188 without this option such a download has to be
4189 performed in two steps: (1) download to RAM, and (2)
4190 copy from RAM to flash.
4192 The two-step approach is usually more reliable, since
4193 you can check if the download worked before you erase
4194 the flash, but in some situations (when system RAM is
4195 too limited to allow for a temporary copy of the
4196 downloaded image) this option may be very useful.
4198 - CONFIG_SYS_FLASH_CFI:
4199 Define if the flash driver uses extra elements in the
4200 common flash structure for storing flash geometry.
4202 - CONFIG_FLASH_CFI_DRIVER
4203 This option also enables the building of the cfi_flash driver
4204 in the drivers directory
4206 - CONFIG_FLASH_CFI_MTD
4207 This option enables the building of the cfi_mtd driver
4208 in the drivers directory. The driver exports CFI flash
4211 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
4212 Use buffered writes to flash.
4214 - CONFIG_FLASH_SPANSION_S29WS_N
4215 s29ws-n MirrorBit flash has non-standard addresses for buffered
4218 - CONFIG_SYS_FLASH_QUIET_TEST
4219 If this option is defined, the common CFI flash doesn't
4220 print it's warning upon not recognized FLASH banks. This
4221 is useful, if some of the configured banks are only
4222 optionally available.
4224 - CONFIG_FLASH_SHOW_PROGRESS
4225 If defined (must be an integer), print out countdown
4226 digits and dots. Recommended value: 45 (9..1) for 80
4227 column displays, 15 (3..1) for 40 column displays.
4229 - CONFIG_FLASH_VERIFY
4230 If defined, the content of the flash (destination) is compared
4231 against the source after the write operation. An error message
4232 will be printed when the contents are not identical.
4233 Please note that this option is useless in nearly all cases,
4234 since such flash programming errors usually are detected earlier
4235 while unprotecting/erasing/programming. Please only enable
4236 this option if you really know what you are doing.
4238 - CONFIG_SYS_RX_ETH_BUFFER:
4239 Defines the number of Ethernet receive buffers. On some
4240 Ethernet controllers it is recommended to set this value
4241 to 8 or even higher (EEPRO100 or 405 EMAC), since all
4242 buffers can be full shortly after enabling the interface
4243 on high Ethernet traffic.
4244 Defaults to 4 if not defined.
4246 - CONFIG_ENV_MAX_ENTRIES
4248 Maximum number of entries in the hash table that is used
4249 internally to store the environment settings. The default
4250 setting is supposed to be generous and should work in most
4251 cases. This setting can be used to tune behaviour; see
4252 lib/hashtable.c for details.
4254 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4255 - CONFIG_ENV_FLAGS_LIST_STATIC
4256 Enable validation of the values given to environment variables when
4257 calling env set. Variables can be restricted to only decimal,
4258 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
4259 the variables can also be restricted to IP address or MAC address.
4261 The format of the list is:
4262 type_attribute = [s|d|x|b|i|m]
4263 access_attribute = [a|r|o|c]
4264 attributes = type_attribute[access_attribute]
4265 entry = variable_name[:attributes]
4268 The type attributes are:
4269 s - String (default)
4272 b - Boolean ([1yYtT|0nNfF])
4276 The access attributes are:
4282 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4283 Define this to a list (string) to define the ".flags"
4284 environment variable in the default or embedded environment.
4286 - CONFIG_ENV_FLAGS_LIST_STATIC
4287 Define this to a list (string) to define validation that
4288 should be done if an entry is not found in the ".flags"
4289 environment variable. To override a setting in the static
4290 list, simply add an entry for the same variable name to the
4293 - CONFIG_ENV_ACCESS_IGNORE_FORCE
4294 If defined, don't allow the -f switch to env set override variable
4297 - CONFIG_SYS_GENERIC_BOARD
4298 This selects the architecture-generic board system instead of the
4299 architecture-specific board files. It is intended to move boards
4300 to this new framework over time. Defining this will disable the
4301 arch/foo/lib/board.c file and use common/board_f.c and
4302 common/board_r.c instead. To use this option your architecture
4303 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
4304 its config.mk file). If you find problems enabling this option on
4305 your board please report the problem and send patches!
4307 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
4308 This is set by OMAP boards for the max time that reset should
4309 be asserted. See doc/README.omap-reset-time for details on how
4310 the value can be calculated on a given board.
4313 If stdint.h is available with your toolchain you can define this
4314 option to enable it. You can provide option 'USE_STDINT=1' when
4315 building U-Boot to enable this.
4317 The following definitions that deal with the placement and management
4318 of environment data (variable area); in general, we support the
4319 following configurations:
4321 - CONFIG_BUILD_ENVCRC:
4323 Builds up envcrc with the target environment so that external utils
4324 may easily extract it and embed it in final U-Boot images.
4326 - CONFIG_ENV_IS_IN_FLASH:
4328 Define this if the environment is in flash memory.
4330 a) The environment occupies one whole flash sector, which is
4331 "embedded" in the text segment with the U-Boot code. This
4332 happens usually with "bottom boot sector" or "top boot
4333 sector" type flash chips, which have several smaller
4334 sectors at the start or the end. For instance, such a
4335 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4336 such a case you would place the environment in one of the
4337 4 kB sectors - with U-Boot code before and after it. With
4338 "top boot sector" type flash chips, you would put the
4339 environment in one of the last sectors, leaving a gap
4340 between U-Boot and the environment.
4342 - CONFIG_ENV_OFFSET:
4344 Offset of environment data (variable area) to the
4345 beginning of flash memory; for instance, with bottom boot
4346 type flash chips the second sector can be used: the offset
4347 for this sector is given here.
4349 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4353 This is just another way to specify the start address of
4354 the flash sector containing the environment (instead of
4357 - CONFIG_ENV_SECT_SIZE:
4359 Size of the sector containing the environment.
4362 b) Sometimes flash chips have few, equal sized, BIG sectors.
4363 In such a case you don't want to spend a whole sector for
4368 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4369 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4370 of this flash sector for the environment. This saves
4371 memory for the RAM copy of the environment.
4373 It may also save flash memory if you decide to use this
4374 when your environment is "embedded" within U-Boot code,
4375 since then the remainder of the flash sector could be used
4376 for U-Boot code. It should be pointed out that this is
4377 STRONGLY DISCOURAGED from a robustness point of view:
4378 updating the environment in flash makes it always
4379 necessary to erase the WHOLE sector. If something goes
4380 wrong before the contents has been restored from a copy in
4381 RAM, your target system will be dead.
4383 - CONFIG_ENV_ADDR_REDUND
4384 CONFIG_ENV_SIZE_REDUND
4386 These settings describe a second storage area used to hold
4387 a redundant copy of the environment data, so that there is
4388 a valid backup copy in case there is a power failure during
4389 a "saveenv" operation.
4391 BE CAREFUL! Any changes to the flash layout, and some changes to the
4392 source code will make it necessary to adapt <board>/u-boot.lds*
4396 - CONFIG_ENV_IS_IN_NVRAM:
4398 Define this if you have some non-volatile memory device
4399 (NVRAM, battery buffered SRAM) which you want to use for the
4405 These two #defines are used to determine the memory area you
4406 want to use for environment. It is assumed that this memory
4407 can just be read and written to, without any special
4410 BE CAREFUL! The first access to the environment happens quite early
4411 in U-Boot initialization (when we try to get the setting of for the
4412 console baudrate). You *MUST* have mapped your NVRAM area then, or
4415 Please note that even with NVRAM we still use a copy of the
4416 environment in RAM: we could work on NVRAM directly, but we want to
4417 keep settings there always unmodified except somebody uses "saveenv"
4418 to save the current settings.
4421 - CONFIG_ENV_IS_IN_EEPROM:
4423 Use this if you have an EEPROM or similar serial access
4424 device and a driver for it.
4426 - CONFIG_ENV_OFFSET:
4429 These two #defines specify the offset and size of the
4430 environment area within the total memory of your EEPROM.
4432 - CONFIG_SYS_I2C_EEPROM_ADDR:
4433 If defined, specified the chip address of the EEPROM device.
4434 The default address is zero.
4436 - CONFIG_SYS_I2C_EEPROM_BUS:
4437 If defined, specified the i2c bus of the EEPROM device.
4439 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4440 If defined, the number of bits used to address bytes in a
4441 single page in the EEPROM device. A 64 byte page, for example
4442 would require six bits.
4444 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4445 If defined, the number of milliseconds to delay between
4446 page writes. The default is zero milliseconds.
4448 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4449 The length in bytes of the EEPROM memory array address. Note
4450 that this is NOT the chip address length!
4452 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4453 EEPROM chips that implement "address overflow" are ones
4454 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4455 address and the extra bits end up in the "chip address" bit
4456 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4459 Note that we consider the length of the address field to
4460 still be one byte because the extra address bits are hidden
4461 in the chip address.
4463 - CONFIG_SYS_EEPROM_SIZE:
4464 The size in bytes of the EEPROM device.
4466 - CONFIG_ENV_EEPROM_IS_ON_I2C
4467 define this, if you have I2C and SPI activated, and your
4468 EEPROM, which holds the environment, is on the I2C bus.
4470 - CONFIG_I2C_ENV_EEPROM_BUS
4471 if you have an Environment on an EEPROM reached over
4472 I2C muxes, you can define here, how to reach this
4473 EEPROM. For example:
4475 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4477 EEPROM which holds the environment, is reached over
4478 a pca9547 i2c mux with address 0x70, channel 3.
4480 - CONFIG_ENV_IS_IN_DATAFLASH:
4482 Define this if you have a DataFlash memory device which you
4483 want to use for the environment.
4485 - CONFIG_ENV_OFFSET:
4489 These three #defines specify the offset and size of the
4490 environment area within the total memory of your DataFlash placed
4491 at the specified address.
4493 - CONFIG_ENV_IS_IN_SPI_FLASH:
4495 Define this if you have a SPI Flash memory device which you
4496 want to use for the environment.
4498 - CONFIG_ENV_OFFSET:
4501 These two #defines specify the offset and size of the
4502 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4503 aligned to an erase sector boundary.
4505 - CONFIG_ENV_SECT_SIZE:
4507 Define the SPI flash's sector size.
4509 - CONFIG_ENV_OFFSET_REDUND (optional):
4511 This setting describes a second storage area of CONFIG_ENV_SIZE
4512 size used to hold a redundant copy of the environment data, so
4513 that there is a valid backup copy in case there is a power failure
4514 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4515 aligned to an erase sector boundary.
4517 - CONFIG_ENV_SPI_BUS (optional):
4518 - CONFIG_ENV_SPI_CS (optional):
4520 Define the SPI bus and chip select. If not defined they will be 0.
4522 - CONFIG_ENV_SPI_MAX_HZ (optional):
4524 Define the SPI max work clock. If not defined then use 1MHz.
4526 - CONFIG_ENV_SPI_MODE (optional):
4528 Define the SPI work mode. If not defined then use SPI_MODE_3.
4530 - CONFIG_ENV_IS_IN_REMOTE:
4532 Define this if you have a remote memory space which you
4533 want to use for the local device's environment.
4538 These two #defines specify the address and size of the
4539 environment area within the remote memory space. The
4540 local device can get the environment from remote memory
4541 space by SRIO or PCIE links.
4543 BE CAREFUL! For some special cases, the local device can not use
4544 "saveenv" command. For example, the local device will get the
4545 environment stored in a remote NOR flash by SRIO or PCIE link,
4546 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4548 - CONFIG_ENV_IS_IN_NAND:
4550 Define this if you have a NAND device which you want to use
4551 for the environment.
4553 - CONFIG_ENV_OFFSET:
4556 These two #defines specify the offset and size of the environment
4557 area within the first NAND device. CONFIG_ENV_OFFSET must be
4558 aligned to an erase block boundary.
4560 - CONFIG_ENV_OFFSET_REDUND (optional):
4562 This setting describes a second storage area of CONFIG_ENV_SIZE
4563 size used to hold a redundant copy of the environment data, so
4564 that there is a valid backup copy in case there is a power failure
4565 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4566 aligned to an erase block boundary.
4568 - CONFIG_ENV_RANGE (optional):
4570 Specifies the length of the region in which the environment
4571 can be written. This should be a multiple of the NAND device's
4572 block size. Specifying a range with more erase blocks than
4573 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4574 the range to be avoided.
4576 - CONFIG_ENV_OFFSET_OOB (optional):
4578 Enables support for dynamically retrieving the offset of the
4579 environment from block zero's out-of-band data. The
4580 "nand env.oob" command can be used to record this offset.
4581 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4582 using CONFIG_ENV_OFFSET_OOB.
4584 - CONFIG_NAND_ENV_DST
4586 Defines address in RAM to which the nand_spl code should copy the
4587 environment. If redundant environment is used, it will be copied to
4588 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4590 - CONFIG_ENV_IS_IN_UBI:
4592 Define this if you have an UBI volume that you want to use for the
4593 environment. This has the benefit of wear-leveling the environment
4594 accesses, which is important on NAND.
4596 - CONFIG_ENV_UBI_PART:
4598 Define this to a string that is the mtd partition containing the UBI.
4600 - CONFIG_ENV_UBI_VOLUME:
4602 Define this to the name of the volume that you want to store the
4605 - CONFIG_ENV_UBI_VOLUME_REDUND:
4607 Define this to the name of another volume to store a second copy of
4608 the environment in. This will enable redundant environments in UBI.
4609 It is assumed that both volumes are in the same MTD partition.
4611 - CONFIG_UBI_SILENCE_MSG
4612 - CONFIG_UBIFS_SILENCE_MSG
4614 You will probably want to define these to avoid a really noisy system
4615 when storing the env in UBI.
4617 - CONFIG_ENV_IS_IN_FAT:
4618 Define this if you want to use the FAT file system for the environment.
4620 - FAT_ENV_INTERFACE:
4622 Define this to a string that is the name of the block device.
4624 - FAT_ENV_DEV_AND_PART:
4626 Define this to a string to specify the partition of the device. It can
4629 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4630 - "D:P": device D partition P. Error occurs if device D has no
4633 - "D" or "D:": device D partition 1 if device D has partition
4634 table, or the whole device D if has no partition
4636 - "D:auto": first partition in device D with bootable flag set.
4637 If none, first valid partition in device D. If no
4638 partition table then means device D.
4642 It's a string of the FAT file name. This file use to store the
4646 This should be defined. Otherwise it cannot save the environment file.
4648 - CONFIG_ENV_IS_IN_MMC:
4650 Define this if you have an MMC device which you want to use for the
4653 - CONFIG_SYS_MMC_ENV_DEV:
4655 Specifies which MMC device the environment is stored in.
4657 - CONFIG_SYS_MMC_ENV_PART (optional):
4659 Specifies which MMC partition the environment is stored in. If not
4660 set, defaults to partition 0, the user area. Common values might be
4661 1 (first MMC boot partition), 2 (second MMC boot partition).
4663 - CONFIG_ENV_OFFSET:
4666 These two #defines specify the offset and size of the environment
4667 area within the specified MMC device.
4669 If offset is positive (the usual case), it is treated as relative to
4670 the start of the MMC partition. If offset is negative, it is treated
4671 as relative to the end of the MMC partition. This can be useful if
4672 your board may be fitted with different MMC devices, which have
4673 different sizes for the MMC partitions, and you always want the
4674 environment placed at the very end of the partition, to leave the
4675 maximum possible space before it, to store other data.
4677 These two values are in units of bytes, but must be aligned to an
4678 MMC sector boundary.
4680 - CONFIG_ENV_OFFSET_REDUND (optional):
4682 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4683 hold a redundant copy of the environment data. This provides a
4684 valid backup copy in case the other copy is corrupted, e.g. due
4685 to a power failure during a "saveenv" operation.
4687 This value may also be positive or negative; this is handled in the
4688 same way as CONFIG_ENV_OFFSET.
4690 This value is also in units of bytes, but must also be aligned to
4691 an MMC sector boundary.
4693 - CONFIG_ENV_SIZE_REDUND (optional):
4695 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4696 set. If this value is set, it must be set to the same value as
4699 - CONFIG_SYS_SPI_INIT_OFFSET
4701 Defines offset to the initial SPI buffer area in DPRAM. The
4702 area is used at an early stage (ROM part) if the environment
4703 is configured to reside in the SPI EEPROM: We need a 520 byte
4704 scratch DPRAM area. It is used between the two initialization
4705 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4706 to be a good choice since it makes it far enough from the
4707 start of the data area as well as from the stack pointer.
4709 Please note that the environment is read-only until the monitor
4710 has been relocated to RAM and a RAM copy of the environment has been
4711 created; also, when using EEPROM you will have to use getenv_f()
4712 until then to read environment variables.
4714 The environment is protected by a CRC32 checksum. Before the monitor
4715 is relocated into RAM, as a result of a bad CRC you will be working
4716 with the compiled-in default environment - *silently*!!! [This is
4717 necessary, because the first environment variable we need is the
4718 "baudrate" setting for the console - if we have a bad CRC, we don't
4719 have any device yet where we could complain.]
4721 Note: once the monitor has been relocated, then it will complain if
4722 the default environment is used; a new CRC is computed as soon as you
4723 use the "saveenv" command to store a valid environment.
4725 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4726 Echo the inverted Ethernet link state to the fault LED.
4728 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4729 also needs to be defined.
4731 - CONFIG_SYS_FAULT_MII_ADDR:
4732 MII address of the PHY to check for the Ethernet link state.
4734 - CONFIG_NS16550_MIN_FUNCTIONS:
4735 Define this if you desire to only have use of the NS16550_init
4736 and NS16550_putc functions for the serial driver located at
4737 drivers/serial/ns16550.c. This option is useful for saving
4738 space for already greatly restricted images, including but not
4739 limited to NAND_SPL configurations.
4741 - CONFIG_DISPLAY_BOARDINFO
4742 Display information about the board that U-Boot is running on
4743 when U-Boot starts up. The board function checkboard() is called
4746 - CONFIG_DISPLAY_BOARDINFO_LATE
4747 Similar to the previous option, but display this information
4748 later, once stdio is running and output goes to the LCD, if
4751 - CONFIG_BOARD_SIZE_LIMIT:
4752 Maximum size of the U-Boot image. When defined, the
4753 build system checks that the actual size does not
4756 Low Level (hardware related) configuration options:
4757 ---------------------------------------------------
4759 - CONFIG_SYS_CACHELINE_SIZE:
4760 Cache Line Size of the CPU.
4762 - CONFIG_SYS_DEFAULT_IMMR:
4763 Default address of the IMMR after system reset.
4765 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4766 and RPXsuper) to be able to adjust the position of
4767 the IMMR register after a reset.
4769 - CONFIG_SYS_CCSRBAR_DEFAULT:
4770 Default (power-on reset) physical address of CCSR on Freescale
4773 - CONFIG_SYS_CCSRBAR:
4774 Virtual address of CCSR. On a 32-bit build, this is typically
4775 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4777 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4778 for cross-platform code that uses that macro instead.
4780 - CONFIG_SYS_CCSRBAR_PHYS:
4781 Physical address of CCSR. CCSR can be relocated to a new
4782 physical address, if desired. In this case, this macro should
4783 be set to that address. Otherwise, it should be set to the
4784 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4785 is typically relocated on 36-bit builds. It is recommended
4786 that this macro be defined via the _HIGH and _LOW macros:
4788 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4789 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4791 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4792 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4793 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4794 used in assembly code, so it must not contain typecasts or
4795 integer size suffixes (e.g. "ULL").
4797 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4798 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4799 used in assembly code, so it must not contain typecasts or
4800 integer size suffixes (e.g. "ULL").
4802 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4803 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4804 forced to a value that ensures that CCSR is not relocated.
4806 - Floppy Disk Support:
4807 CONFIG_SYS_FDC_DRIVE_NUMBER
4809 the default drive number (default value 0)
4811 CONFIG_SYS_ISA_IO_STRIDE
4813 defines the spacing between FDC chipset registers
4816 CONFIG_SYS_ISA_IO_OFFSET
4818 defines the offset of register from address. It
4819 depends on which part of the data bus is connected to
4820 the FDC chipset. (default value 0)
4822 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4823 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4826 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4827 fdc_hw_init() is called at the beginning of the FDC
4828 setup. fdc_hw_init() must be provided by the board
4829 source code. It is used to make hardware-dependent
4833 Most IDE controllers were designed to be connected with PCI
4834 interface. Only few of them were designed for AHB interface.
4835 When software is doing ATA command and data transfer to
4836 IDE devices through IDE-AHB controller, some additional
4837 registers accessing to these kind of IDE-AHB controller
4840 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4841 DO NOT CHANGE unless you know exactly what you're
4842 doing! (11-4) [MPC8xx/82xx systems only]
4844 - CONFIG_SYS_INIT_RAM_ADDR:
4846 Start address of memory area that can be used for
4847 initial data and stack; please note that this must be
4848 writable memory that is working WITHOUT special
4849 initialization, i. e. you CANNOT use normal RAM which
4850 will become available only after programming the
4851 memory controller and running certain initialization
4854 U-Boot uses the following memory types:
4855 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4856 - MPC824X: data cache
4857 - PPC4xx: data cache
4859 - CONFIG_SYS_GBL_DATA_OFFSET:
4861 Offset of the initial data structure in the memory
4862 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4863 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4864 data is located at the end of the available space
4865 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4866 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4867 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4868 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4871 On the MPC824X (or other systems that use the data
4872 cache for initial memory) the address chosen for
4873 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4874 point to an otherwise UNUSED address space between
4875 the top of RAM and the start of the PCI space.
4877 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4879 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4881 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4883 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4885 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4887 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4889 - CONFIG_SYS_OR_TIMING_SDRAM:
4892 - CONFIG_SYS_MAMR_PTA:
4893 periodic timer for refresh
4895 - CONFIG_SYS_DER: Debug Event Register (37-47)
4897 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4898 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4899 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4900 CONFIG_SYS_BR1_PRELIM:
4901 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4903 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4904 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4905 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4906 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4908 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4909 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4910 Machine Mode Register and Memory Periodic Timer
4911 Prescaler definitions (SDRAM timing)
4913 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4914 enable I2C microcode relocation patch (MPC8xx);
4915 define relocation offset in DPRAM [DSP2]
4917 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4918 enable SMC microcode relocation patch (MPC8xx);
4919 define relocation offset in DPRAM [SMC1]
4921 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4922 enable SPI microcode relocation patch (MPC8xx);
4923 define relocation offset in DPRAM [SCC4]
4925 - CONFIG_SYS_USE_OSCCLK:
4926 Use OSCM clock mode on MBX8xx board. Be careful,
4927 wrong setting might damage your board. Read
4928 doc/README.MBX before setting this variable!
4930 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4931 Offset of the bootmode word in DPRAM used by post
4932 (Power On Self Tests). This definition overrides
4933 #define'd default value in commproc.h resp.
4936 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4937 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4938 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4939 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4940 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4941 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4942 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4943 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4944 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4946 - CONFIG_PCI_DISABLE_PCIE:
4947 Disable PCI-Express on systems where it is supported but not
4950 - CONFIG_PCI_ENUM_ONLY
4951 Only scan through and get the devices on the buses.
4952 Don't do any setup work, presumably because someone or
4953 something has already done it, and we don't need to do it
4954 a second time. Useful for platforms that are pre-booted
4955 by coreboot or similar.
4957 - CONFIG_PCI_INDIRECT_BRIDGE:
4958 Enable support for indirect PCI bridges.
4961 Chip has SRIO or not
4964 Board has SRIO 1 port available
4967 Board has SRIO 2 port available
4969 - CONFIG_SRIO_PCIE_BOOT_MASTER
4970 Board can support master function for Boot from SRIO and PCIE
4972 - CONFIG_SYS_SRIOn_MEM_VIRT:
4973 Virtual Address of SRIO port 'n' memory region
4975 - CONFIG_SYS_SRIOn_MEM_PHYS:
4976 Physical Address of SRIO port 'n' memory region
4978 - CONFIG_SYS_SRIOn_MEM_SIZE:
4979 Size of SRIO port 'n' memory region
4981 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4982 Defined to tell the NAND controller that the NAND chip is using
4984 Not all NAND drivers use this symbol.
4985 Example of drivers that use it:
4986 - drivers/mtd/nand/ndfc.c
4987 - drivers/mtd/nand/mxc_nand.c
4989 - CONFIG_SYS_NDFC_EBC0_CFG
4990 Sets the EBC0_CFG register for the NDFC. If not defined
4991 a default value will be used.
4994 Get DDR timing information from an I2C EEPROM. Common
4995 with pluggable memory modules such as SODIMMs
4998 I2C address of the SPD EEPROM
5000 - CONFIG_SYS_SPD_BUS_NUM
5001 If SPD EEPROM is on an I2C bus other than the first
5002 one, specify here. Note that the value must resolve
5003 to something your driver can deal with.
5005 - CONFIG_SYS_DDR_RAW_TIMING
5006 Get DDR timing information from other than SPD. Common with
5007 soldered DDR chips onboard without SPD. DDR raw timing
5008 parameters are extracted from datasheet and hard-coded into
5009 header files or board specific files.
5011 - CONFIG_FSL_DDR_INTERACTIVE
5012 Enable interactive DDR debugging. See doc/README.fsl-ddr.
5014 - CONFIG_FSL_DDR_SYNC_REFRESH
5015 Enable sync of refresh for multiple controllers.
5017 - CONFIG_SYS_83XX_DDR_USES_CS0
5018 Only for 83xx systems. If specified, then DDR should
5019 be configured using CS0 and CS1 instead of CS2 and CS3.
5021 - CONFIG_ETHER_ON_FEC[12]
5022 Define to enable FEC[12] on a 8xx series processor.
5024 - CONFIG_FEC[12]_PHY
5025 Define to the hardcoded PHY address which corresponds
5026 to the given FEC; i. e.
5027 #define CONFIG_FEC1_PHY 4
5028 means that the PHY with address 4 is connected to FEC1
5030 When set to -1, means to probe for first available.
5032 - CONFIG_FEC[12]_PHY_NORXERR
5033 The PHY does not have a RXERR line (RMII only).
5034 (so program the FEC to ignore it).
5037 Enable RMII mode for all FECs.
5038 Note that this is a global option, we can't
5039 have one FEC in standard MII mode and another in RMII mode.
5041 - CONFIG_CRC32_VERIFY
5042 Add a verify option to the crc32 command.
5045 => crc32 -v <address> <count> <crc32>
5047 Where address/count indicate a memory area
5048 and crc32 is the correct crc32 which the
5052 Add the "loopw" memory command. This only takes effect if
5053 the memory commands are activated globally (CONFIG_CMD_MEM).
5056 Add the "mdc" and "mwc" memory commands. These are cyclic
5061 This command will print 4 bytes (10,11,12,13) each 500 ms.
5063 => mwc.l 100 12345678 10
5064 This command will write 12345678 to address 100 all 10 ms.
5066 This only takes effect if the memory commands are activated
5067 globally (CONFIG_CMD_MEM).
5069 - CONFIG_SKIP_LOWLEVEL_INIT
5070 [ARM, NDS32, MIPS only] If this variable is defined, then certain
5071 low level initializations (like setting up the memory
5072 controller) are omitted and/or U-Boot does not
5073 relocate itself into RAM.
5075 Normally this variable MUST NOT be defined. The only
5076 exception is when U-Boot is loaded (to RAM) by some
5077 other boot loader or by a debugger which performs
5078 these initializations itself.
5081 Modifies the behaviour of start.S when compiling a loader
5082 that is executed before the actual U-Boot. E.g. when
5083 compiling a NAND SPL.
5086 Modifies the behaviour of start.S when compiling a loader
5087 that is executed after the SPL and before the actual U-Boot.
5088 It is loaded by the SPL.
5090 - CONFIG_SYS_MPC85XX_NO_RESETVEC
5091 Only for 85xx systems. If this variable is specified, the section
5092 .resetvec is not kept and the section .bootpg is placed in the
5093 previous 4k of the .text section.
5095 - CONFIG_ARCH_MAP_SYSMEM
5096 Generally U-Boot (and in particular the md command) uses
5097 effective address. It is therefore not necessary to regard
5098 U-Boot address as virtual addresses that need to be translated
5099 to physical addresses. However, sandbox requires this, since
5100 it maintains its own little RAM buffer which contains all
5101 addressable memory. This option causes some memory accesses
5102 to be mapped through map_sysmem() / unmap_sysmem().
5104 - CONFIG_USE_ARCH_MEMCPY
5105 CONFIG_USE_ARCH_MEMSET
5106 If these options are used a optimized version of memcpy/memset will
5107 be used if available. These functions may be faster under some
5108 conditions but may increase the binary size.
5110 - CONFIG_X86_RESET_VECTOR
5111 If defined, the x86 reset vector code is included. This is not
5112 needed when U-Boot is running from Coreboot.
5115 Defines the MPU clock speed (in MHz).
5117 NOTE : currently only supported on AM335x platforms.
5119 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
5120 Enables the RTC32K OSC on AM33xx based plattforms
5122 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
5123 Option to disable subpage write in NAND driver
5124 driver that uses this:
5125 drivers/mtd/nand/davinci_nand.c
5127 Freescale QE/FMAN Firmware Support:
5128 -----------------------------------
5130 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
5131 loading of "firmware", which is encoded in the QE firmware binary format.
5132 This firmware often needs to be loaded during U-Boot booting, so macros
5133 are used to identify the storage device (NOR flash, SPI, etc) and the address
5136 - CONFIG_SYS_FMAN_FW_ADDR
5137 The address in the storage device where the FMAN microcode is located. The
5138 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5141 - CONFIG_SYS_QE_FW_ADDR
5142 The address in the storage device where the QE microcode is located. The
5143 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5146 - CONFIG_SYS_QE_FMAN_FW_LENGTH
5147 The maximum possible size of the firmware. The firmware binary format
5148 has a field that specifies the actual size of the firmware, but it
5149 might not be possible to read any part of the firmware unless some
5150 local storage is allocated to hold the entire firmware first.
5152 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
5153 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
5154 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
5155 virtual address in NOR flash.
5157 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
5158 Specifies that QE/FMAN firmware is located in NAND flash.
5159 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
5161 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
5162 Specifies that QE/FMAN firmware is located on the primary SD/MMC
5163 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5165 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
5166 Specifies that QE/FMAN firmware is located on the primary SPI
5167 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5169 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
5170 Specifies that QE/FMAN firmware is located in the remote (master)
5171 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
5172 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
5173 window->master inbound window->master LAW->the ucode address in
5174 master's memory space.
5176 Freescale Layerscape Management Complex Firmware Support:
5177 ---------------------------------------------------------
5178 The Freescale Layerscape Management Complex (MC) supports the loading of
5180 This firmware often needs to be loaded during U-Boot booting, so macros
5181 are used to identify the storage device (NOR flash, SPI, etc) and the address
5184 - CONFIG_FSL_MC_ENET
5185 Enable the MC driver for Layerscape SoCs.
5187 - CONFIG_SYS_LS_MC_FW_ADDR
5188 The address in the storage device where the firmware is located. The
5189 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
5192 - CONFIG_SYS_LS_MC_FW_LENGTH
5193 The maximum possible size of the firmware. The firmware binary format
5194 has a field that specifies the actual size of the firmware, but it
5195 might not be possible to read any part of the firmware unless some
5196 local storage is allocated to hold the entire firmware first.
5198 - CONFIG_SYS_LS_MC_FW_IN_NOR
5199 Specifies that MC firmware is located in NOR flash, mapped as
5200 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
5201 virtual address in NOR flash.
5203 Building the Software:
5204 ======================
5206 Building U-Boot has been tested in several native build environments
5207 and in many different cross environments. Of course we cannot support
5208 all possibly existing versions of cross development tools in all
5209 (potentially obsolete) versions. In case of tool chain problems we
5210 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
5211 which is extensively used to build and test U-Boot.
5213 If you are not using a native environment, it is assumed that you
5214 have GNU cross compiling tools available in your path. In this case,
5215 you must set the environment variable CROSS_COMPILE in your shell.
5216 Note that no changes to the Makefile or any other source files are
5217 necessary. For example using the ELDK on a 4xx CPU, please enter:
5219 $ CROSS_COMPILE=ppc_4xx-
5220 $ export CROSS_COMPILE
5222 Note: If you wish to generate Windows versions of the utilities in
5223 the tools directory you can use the MinGW toolchain
5224 (http://www.mingw.org). Set your HOST tools to the MinGW
5225 toolchain and execute 'make tools'. For example:
5227 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
5229 Binaries such as tools/mkimage.exe will be created which can
5230 be executed on computers running Windows.
5232 U-Boot is intended to be simple to build. After installing the
5233 sources you must configure U-Boot for one specific board type. This
5238 where "NAME_defconfig" is the name of one of the existing configu-
5239 rations; see boards.cfg for supported names.
5241 Note: for some board special configuration names may exist; check if
5242 additional information is available from the board vendor; for
5243 instance, the TQM823L systems are available without (standard)
5244 or with LCD support. You can select such additional "features"
5245 when choosing the configuration, i. e.
5247 make TQM823L_defconfig
5248 - will configure for a plain TQM823L, i. e. no LCD support
5250 make TQM823L_LCD_defconfig
5251 - will configure for a TQM823L with U-Boot console on LCD
5256 Finally, type "make all", and you should get some working U-Boot
5257 images ready for download to / installation on your system:
5259 - "u-boot.bin" is a raw binary image
5260 - "u-boot" is an image in ELF binary format
5261 - "u-boot.srec" is in Motorola S-Record format
5263 By default the build is performed locally and the objects are saved
5264 in the source directory. One of the two methods can be used to change
5265 this behavior and build U-Boot to some external directory:
5267 1. Add O= to the make command line invocations:
5269 make O=/tmp/build distclean
5270 make O=/tmp/build NAME_defconfig
5271 make O=/tmp/build all
5273 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
5275 export KBUILD_OUTPUT=/tmp/build
5280 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
5284 Please be aware that the Makefiles assume you are using GNU make, so
5285 for instance on NetBSD you might need to use "gmake" instead of
5289 If the system board that you have is not listed, then you will need
5290 to port U-Boot to your hardware platform. To do this, follow these
5293 1. Add a new configuration option for your board to the toplevel
5294 "boards.cfg" file, using the existing entries as examples.
5295 Follow the instructions there to keep the boards in order.
5296 2. Create a new directory to hold your board specific code. Add any
5297 files you need. In your board directory, you will need at least
5298 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
5299 3. Create a new configuration file "include/configs/<board>.h" for
5301 3. If you're porting U-Boot to a new CPU, then also create a new
5302 directory to hold your CPU specific code. Add any files you need.
5303 4. Run "make <board>_defconfig" with your new name.
5304 5. Type "make", and you should get a working "u-boot.srec" file
5305 to be installed on your target system.
5306 6. Debug and solve any problems that might arise.
5307 [Of course, this last step is much harder than it sounds.]
5310 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5311 ==============================================================
5313 If you have modified U-Boot sources (for instance added a new board
5314 or support for new devices, a new CPU, etc.) you are expected to
5315 provide feedback to the other developers. The feedback normally takes
5316 the form of a "patch", i. e. a context diff against a certain (latest
5317 official or latest in the git repository) version of U-Boot sources.
5319 But before you submit such a patch, please verify that your modifi-
5320 cation did not break existing code. At least make sure that *ALL* of
5321 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5322 just run the "MAKEALL" script, which will configure and build U-Boot
5323 for ALL supported system. Be warned, this will take a while. You can
5324 select which (cross) compiler to use by passing a `CROSS_COMPILE'
5325 environment variable to the script, i. e. to use the ELDK cross tools
5328 CROSS_COMPILE=ppc_8xx- MAKEALL
5330 or to build on a native PowerPC system you can type
5332 CROSS_COMPILE=' ' MAKEALL
5334 When using the MAKEALL script, the default behaviour is to build
5335 U-Boot in the source directory. This location can be changed by
5336 setting the BUILD_DIR environment variable. Also, for each target
5337 built, the MAKEALL script saves two log files (<target>.ERR and
5338 <target>.MAKEALL) in the <source dir>/LOG directory. This default
5339 location can be changed by setting the MAKEALL_LOGDIR environment
5340 variable. For example:
5342 export BUILD_DIR=/tmp/build
5343 export MAKEALL_LOGDIR=/tmp/log
5344 CROSS_COMPILE=ppc_8xx- MAKEALL
5346 With the above settings build objects are saved in the /tmp/build,
5347 log files are saved in the /tmp/log and the source tree remains clean
5348 during the whole build process.
5351 See also "U-Boot Porting Guide" below.
5354 Monitor Commands - Overview:
5355 ============================
5357 go - start application at address 'addr'
5358 run - run commands in an environment variable
5359 bootm - boot application image from memory
5360 bootp - boot image via network using BootP/TFTP protocol
5361 bootz - boot zImage from memory
5362 tftpboot- boot image via network using TFTP protocol
5363 and env variables "ipaddr" and "serverip"
5364 (and eventually "gatewayip")
5365 tftpput - upload a file via network using TFTP protocol
5366 rarpboot- boot image via network using RARP/TFTP protocol
5367 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5368 loads - load S-Record file over serial line
5369 loadb - load binary file over serial line (kermit mode)
5371 mm - memory modify (auto-incrementing)
5372 nm - memory modify (constant address)
5373 mw - memory write (fill)
5375 cmp - memory compare
5376 crc32 - checksum calculation
5377 i2c - I2C sub-system
5378 sspi - SPI utility commands
5379 base - print or set address offset
5380 printenv- print environment variables
5381 setenv - set environment variables
5382 saveenv - save environment variables to persistent storage
5383 protect - enable or disable FLASH write protection
5384 erase - erase FLASH memory
5385 flinfo - print FLASH memory information
5386 nand - NAND memory operations (see doc/README.nand)
5387 bdinfo - print Board Info structure
5388 iminfo - print header information for application image
5389 coninfo - print console devices and informations
5390 ide - IDE sub-system
5391 loop - infinite loop on address range
5392 loopw - infinite write loop on address range
5393 mtest - simple RAM test
5394 icache - enable or disable instruction cache
5395 dcache - enable or disable data cache
5396 reset - Perform RESET of the CPU
5397 echo - echo args to console
5398 version - print monitor version
5399 help - print online help
5400 ? - alias for 'help'
5403 Monitor Commands - Detailed Description:
5404 ========================================
5408 For now: just type "help <command>".
5411 Environment Variables:
5412 ======================
5414 U-Boot supports user configuration using Environment Variables which
5415 can be made persistent by saving to Flash memory.
5417 Environment Variables are set using "setenv", printed using
5418 "printenv", and saved to Flash using "saveenv". Using "setenv"
5419 without a value can be used to delete a variable from the
5420 environment. As long as you don't save the environment you are
5421 working with an in-memory copy. In case the Flash area containing the
5422 environment is erased by accident, a default environment is provided.
5424 Some configuration options can be set using Environment Variables.
5426 List of environment variables (most likely not complete):
5428 baudrate - see CONFIG_BAUDRATE
5430 bootdelay - see CONFIG_BOOTDELAY
5432 bootcmd - see CONFIG_BOOTCOMMAND
5434 bootargs - Boot arguments when booting an RTOS image
5436 bootfile - Name of the image to load with TFTP
5438 bootm_low - Memory range available for image processing in the bootm
5439 command can be restricted. This variable is given as
5440 a hexadecimal number and defines lowest address allowed
5441 for use by the bootm command. See also "bootm_size"
5442 environment variable. Address defined by "bootm_low" is
5443 also the base of the initial memory mapping for the Linux
5444 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5447 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5448 This variable is given as a hexadecimal number and it
5449 defines the size of the memory region starting at base
5450 address bootm_low that is accessible by the Linux kernel
5451 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5452 as the default value if it is defined, and bootm_size is
5455 bootm_size - Memory range available for image processing in the bootm
5456 command can be restricted. This variable is given as
5457 a hexadecimal number and defines the size of the region
5458 allowed for use by the bootm command. See also "bootm_low"
5459 environment variable.
5461 updatefile - Location of the software update file on a TFTP server, used
5462 by the automatic software update feature. Please refer to
5463 documentation in doc/README.update for more details.
5465 autoload - if set to "no" (any string beginning with 'n'),
5466 "bootp" will just load perform a lookup of the
5467 configuration from the BOOTP server, but not try to
5468 load any image using TFTP
5470 autostart - if set to "yes", an image loaded using the "bootp",
5471 "rarpboot", "tftpboot" or "diskboot" commands will
5472 be automatically started (by internally calling
5475 If set to "no", a standalone image passed to the
5476 "bootm" command will be copied to the load address
5477 (and eventually uncompressed), but NOT be started.
5478 This can be used to load and uncompress arbitrary
5481 fdt_high - if set this restricts the maximum address that the
5482 flattened device tree will be copied into upon boot.
5483 For example, if you have a system with 1 GB memory
5484 at physical address 0x10000000, while Linux kernel
5485 only recognizes the first 704 MB as low memory, you
5486 may need to set fdt_high as 0x3C000000 to have the
5487 device tree blob be copied to the maximum address
5488 of the 704 MB low memory, so that Linux kernel can
5489 access it during the boot procedure.
5491 If this is set to the special value 0xFFFFFFFF then
5492 the fdt will not be copied at all on boot. For this
5493 to work it must reside in writable memory, have
5494 sufficient padding on the end of it for u-boot to
5495 add the information it needs into it, and the memory
5496 must be accessible by the kernel.
5498 fdtcontroladdr- if set this is the address of the control flattened
5499 device tree used by U-Boot when CONFIG_OF_CONTROL is
5502 i2cfast - (PPC405GP|PPC405EP only)
5503 if set to 'y' configures Linux I2C driver for fast
5504 mode (400kHZ). This environment variable is used in
5505 initialization code. So, for changes to be effective
5506 it must be saved and board must be reset.
5508 initrd_high - restrict positioning of initrd images:
5509 If this variable is not set, initrd images will be
5510 copied to the highest possible address in RAM; this
5511 is usually what you want since it allows for
5512 maximum initrd size. If for some reason you want to
5513 make sure that the initrd image is loaded below the
5514 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5515 variable to a value of "no" or "off" or "0".
5516 Alternatively, you can set it to a maximum upper
5517 address to use (U-Boot will still check that it
5518 does not overwrite the U-Boot stack and data).
5520 For instance, when you have a system with 16 MB
5521 RAM, and want to reserve 4 MB from use by Linux,
5522 you can do this by adding "mem=12M" to the value of
5523 the "bootargs" variable. However, now you must make
5524 sure that the initrd image is placed in the first
5525 12 MB as well - this can be done with
5527 setenv initrd_high 00c00000
5529 If you set initrd_high to 0xFFFFFFFF, this is an
5530 indication to U-Boot that all addresses are legal
5531 for the Linux kernel, including addresses in flash
5532 memory. In this case U-Boot will NOT COPY the
5533 ramdisk at all. This may be useful to reduce the
5534 boot time on your system, but requires that this
5535 feature is supported by your Linux kernel.
5537 ipaddr - IP address; needed for tftpboot command
5539 loadaddr - Default load address for commands like "bootp",
5540 "rarpboot", "tftpboot", "loadb" or "diskboot"
5542 loads_echo - see CONFIG_LOADS_ECHO
5544 serverip - TFTP server IP address; needed for tftpboot command
5546 bootretry - see CONFIG_BOOT_RETRY_TIME
5548 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5550 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5552 ethprime - controls which interface is used first.
5554 ethact - controls which interface is currently active.
5555 For example you can do the following
5557 => setenv ethact FEC
5558 => ping 192.168.0.1 # traffic sent on FEC
5559 => setenv ethact SCC
5560 => ping 10.0.0.1 # traffic sent on SCC
5562 ethrotate - When set to "no" U-Boot does not go through all
5563 available network interfaces.
5564 It just stays at the currently selected interface.
5566 netretry - When set to "no" each network operation will
5567 either succeed or fail without retrying.
5568 When set to "once" the network operation will
5569 fail when all the available network interfaces
5570 are tried once without success.
5571 Useful on scripts which control the retry operation
5574 npe_ucode - set load address for the NPE microcode
5576 silent_linux - If set then Linux will be told to boot silently, by
5577 changing the console to be empty. If "yes" it will be
5578 made silent. If "no" it will not be made silent. If
5579 unset, then it will be made silent if the U-Boot console
5582 tftpsrcport - If this is set, the value is used for TFTP's
5585 tftpdstport - If this is set, the value is used for TFTP's UDP
5586 destination port instead of the Well Know Port 69.
5588 tftpblocksize - Block size to use for TFTP transfers; if not set,
5589 we use the TFTP server's default block size
5591 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5592 seconds, minimum value is 1000 = 1 second). Defines
5593 when a packet is considered to be lost so it has to
5594 be retransmitted. The default is 5000 = 5 seconds.
5595 Lowering this value may make downloads succeed
5596 faster in networks with high packet loss rates or
5597 with unreliable TFTP servers.
5599 vlan - When set to a value < 4095 the traffic over
5600 Ethernet is encapsulated/received over 802.1q
5603 The following image location variables contain the location of images
5604 used in booting. The "Image" column gives the role of the image and is
5605 not an environment variable name. The other columns are environment
5606 variable names. "File Name" gives the name of the file on a TFTP
5607 server, "RAM Address" gives the location in RAM the image will be
5608 loaded to, and "Flash Location" gives the image's address in NOR
5609 flash or offset in NAND flash.
5611 *Note* - these variables don't have to be defined for all boards, some
5612 boards currenlty use other variables for these purposes, and some
5613 boards use these variables for other purposes.
5615 Image File Name RAM Address Flash Location
5616 ----- --------- ----------- --------------
5617 u-boot u-boot u-boot_addr_r u-boot_addr
5618 Linux kernel bootfile kernel_addr_r kernel_addr
5619 device tree blob fdtfile fdt_addr_r fdt_addr
5620 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5622 The following environment variables may be used and automatically
5623 updated by the network boot commands ("bootp" and "rarpboot"),
5624 depending the information provided by your boot server:
5626 bootfile - see above
5627 dnsip - IP address of your Domain Name Server
5628 dnsip2 - IP address of your secondary Domain Name Server
5629 gatewayip - IP address of the Gateway (Router) to use
5630 hostname - Target hostname
5632 netmask - Subnet Mask
5633 rootpath - Pathname of the root filesystem on the NFS server
5634 serverip - see above
5637 There are two special Environment Variables:
5639 serial# - contains hardware identification information such
5640 as type string and/or serial number
5641 ethaddr - Ethernet address
5643 These variables can be set only once (usually during manufacturing of
5644 the board). U-Boot refuses to delete or overwrite these variables
5645 once they have been set once.
5648 Further special Environment Variables:
5650 ver - Contains the U-Boot version string as printed
5651 with the "version" command. This variable is
5652 readonly (see CONFIG_VERSION_VARIABLE).
5655 Please note that changes to some configuration parameters may take
5656 only effect after the next boot (yes, that's just like Windoze :-).
5659 Callback functions for environment variables:
5660 ---------------------------------------------
5662 For some environment variables, the behavior of u-boot needs to change
5663 when their values are changed. This functionality allows functions to
5664 be associated with arbitrary variables. On creation, overwrite, or
5665 deletion, the callback will provide the opportunity for some side
5666 effect to happen or for the change to be rejected.
5668 The callbacks are named and associated with a function using the
5669 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5671 These callbacks are associated with variables in one of two ways. The
5672 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5673 in the board configuration to a string that defines a list of
5674 associations. The list must be in the following format:
5676 entry = variable_name[:callback_name]
5679 If the callback name is not specified, then the callback is deleted.
5680 Spaces are also allowed anywhere in the list.
5682 Callbacks can also be associated by defining the ".callbacks" variable
5683 with the same list format above. Any association in ".callbacks" will
5684 override any association in the static list. You can define
5685 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5686 ".callbacks" environment variable in the default or embedded environment.
5689 Command Line Parsing:
5690 =====================
5692 There are two different command line parsers available with U-Boot:
5693 the old "simple" one, and the much more powerful "hush" shell:
5695 Old, simple command line parser:
5696 --------------------------------
5698 - supports environment variables (through setenv / saveenv commands)
5699 - several commands on one line, separated by ';'
5700 - variable substitution using "... ${name} ..." syntax
5701 - special characters ('$', ';') can be escaped by prefixing with '\',
5703 setenv bootcmd bootm \${address}
5704 - You can also escape text by enclosing in single apostrophes, for example:
5705 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5710 - similar to Bourne shell, with control structures like
5711 if...then...else...fi, for...do...done; while...do...done,
5712 until...do...done, ...
5713 - supports environment ("global") variables (through setenv / saveenv
5714 commands) and local shell variables (through standard shell syntax
5715 "name=value"); only environment variables can be used with "run"
5721 (1) If a command line (or an environment variable executed by a "run"
5722 command) contains several commands separated by semicolon, and
5723 one of these commands fails, then the remaining commands will be
5726 (2) If you execute several variables with one call to run (i. e.
5727 calling run with a list of variables as arguments), any failing
5728 command will cause "run" to terminate, i. e. the remaining
5729 variables are not executed.
5731 Note for Redundant Ethernet Interfaces:
5732 =======================================
5734 Some boards come with redundant Ethernet interfaces; U-Boot supports
5735 such configurations and is capable of automatic selection of a
5736 "working" interface when needed. MAC assignment works as follows:
5738 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5739 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5740 "eth1addr" (=>eth1), "eth2addr", ...
5742 If the network interface stores some valid MAC address (for instance
5743 in SROM), this is used as default address if there is NO correspon-
5744 ding setting in the environment; if the corresponding environment
5745 variable is set, this overrides the settings in the card; that means:
5747 o If the SROM has a valid MAC address, and there is no address in the
5748 environment, the SROM's address is used.
5750 o If there is no valid address in the SROM, and a definition in the
5751 environment exists, then the value from the environment variable is
5754 o If both the SROM and the environment contain a MAC address, and
5755 both addresses are the same, this MAC address is used.
5757 o If both the SROM and the environment contain a MAC address, and the
5758 addresses differ, the value from the environment is used and a
5761 o If neither SROM nor the environment contain a MAC address, an error
5764 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5765 will be programmed into hardware as part of the initialization process. This
5766 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5767 The naming convention is as follows:
5768 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5773 U-Boot is capable of booting (and performing other auxiliary operations on)
5774 images in two formats:
5776 New uImage format (FIT)
5777 -----------------------
5779 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5780 to Flattened Device Tree). It allows the use of images with multiple
5781 components (several kernels, ramdisks, etc.), with contents protected by
5782 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5788 Old image format is based on binary files which can be basically anything,
5789 preceded by a special header; see the definitions in include/image.h for
5790 details; basically, the header defines the following image properties:
5792 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5793 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5794 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5795 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5797 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5798 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5799 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5800 * Compression Type (uncompressed, gzip, bzip2)
5806 The header is marked by a special Magic Number, and both the header
5807 and the data portions of the image are secured against corruption by
5814 Although U-Boot should support any OS or standalone application
5815 easily, the main focus has always been on Linux during the design of
5818 U-Boot includes many features that so far have been part of some
5819 special "boot loader" code within the Linux kernel. Also, any
5820 "initrd" images to be used are no longer part of one big Linux image;
5821 instead, kernel and "initrd" are separate images. This implementation
5822 serves several purposes:
5824 - the same features can be used for other OS or standalone
5825 applications (for instance: using compressed images to reduce the
5826 Flash memory footprint)
5828 - it becomes much easier to port new Linux kernel versions because
5829 lots of low-level, hardware dependent stuff are done by U-Boot
5831 - the same Linux kernel image can now be used with different "initrd"
5832 images; of course this also means that different kernel images can
5833 be run with the same "initrd". This makes testing easier (you don't
5834 have to build a new "zImage.initrd" Linux image when you just
5835 change a file in your "initrd"). Also, a field-upgrade of the
5836 software is easier now.
5842 Porting Linux to U-Boot based systems:
5843 ---------------------------------------
5845 U-Boot cannot save you from doing all the necessary modifications to
5846 configure the Linux device drivers for use with your target hardware
5847 (no, we don't intend to provide a full virtual machine interface to
5850 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5852 Just make sure your machine specific header file (for instance
5853 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5854 Information structure as we define in include/asm-<arch>/u-boot.h,
5855 and make sure that your definition of IMAP_ADDR uses the same value
5856 as your U-Boot configuration in CONFIG_SYS_IMMR.
5858 Note that U-Boot now has a driver model, a unified model for drivers.
5859 If you are adding a new driver, plumb it into driver model. If there
5860 is no uclass available, you are encouraged to create one. See
5864 Configuring the Linux kernel:
5865 -----------------------------
5867 No specific requirements for U-Boot. Make sure you have some root
5868 device (initial ramdisk, NFS) for your target system.
5871 Building a Linux Image:
5872 -----------------------
5874 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5875 not used. If you use recent kernel source, a new build target
5876 "uImage" will exist which automatically builds an image usable by
5877 U-Boot. Most older kernels also have support for a "pImage" target,
5878 which was introduced for our predecessor project PPCBoot and uses a
5879 100% compatible format.
5883 make TQM850L_defconfig
5888 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5889 encapsulate a compressed Linux kernel image with header information,
5890 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5892 * build a standard "vmlinux" kernel image (in ELF binary format):
5894 * convert the kernel into a raw binary image:
5896 ${CROSS_COMPILE}-objcopy -O binary \
5897 -R .note -R .comment \
5898 -S vmlinux linux.bin
5900 * compress the binary image:
5904 * package compressed binary image for U-Boot:
5906 mkimage -A ppc -O linux -T kernel -C gzip \
5907 -a 0 -e 0 -n "Linux Kernel Image" \
5908 -d linux.bin.gz uImage
5911 The "mkimage" tool can also be used to create ramdisk images for use
5912 with U-Boot, either separated from the Linux kernel image, or
5913 combined into one file. "mkimage" encapsulates the images with a 64
5914 byte header containing information about target architecture,
5915 operating system, image type, compression method, entry points, time
5916 stamp, CRC32 checksums, etc.
5918 "mkimage" can be called in two ways: to verify existing images and
5919 print the header information, or to build new images.
5921 In the first form (with "-l" option) mkimage lists the information
5922 contained in the header of an existing U-Boot image; this includes
5923 checksum verification:
5925 tools/mkimage -l image
5926 -l ==> list image header information
5928 The second form (with "-d" option) is used to build a U-Boot image
5929 from a "data file" which is used as image payload:
5931 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5932 -n name -d data_file image
5933 -A ==> set architecture to 'arch'
5934 -O ==> set operating system to 'os'
5935 -T ==> set image type to 'type'
5936 -C ==> set compression type 'comp'
5937 -a ==> set load address to 'addr' (hex)
5938 -e ==> set entry point to 'ep' (hex)
5939 -n ==> set image name to 'name'
5940 -d ==> use image data from 'datafile'
5942 Right now, all Linux kernels for PowerPC systems use the same load
5943 address (0x00000000), but the entry point address depends on the
5946 - 2.2.x kernels have the entry point at 0x0000000C,
5947 - 2.3.x and later kernels have the entry point at 0x00000000.
5949 So a typical call to build a U-Boot image would read:
5951 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5952 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5953 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5954 > examples/uImage.TQM850L
5955 Image Name: 2.4.4 kernel for TQM850L
5956 Created: Wed Jul 19 02:34:59 2000
5957 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5958 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5959 Load Address: 0x00000000
5960 Entry Point: 0x00000000
5962 To verify the contents of the image (or check for corruption):
5964 -> tools/mkimage -l examples/uImage.TQM850L
5965 Image Name: 2.4.4 kernel for TQM850L
5966 Created: Wed Jul 19 02:34:59 2000
5967 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5968 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5969 Load Address: 0x00000000
5970 Entry Point: 0x00000000
5972 NOTE: for embedded systems where boot time is critical you can trade
5973 speed for memory and install an UNCOMPRESSED image instead: this
5974 needs more space in Flash, but boots much faster since it does not
5975 need to be uncompressed:
5977 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5978 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5979 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5980 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5981 > examples/uImage.TQM850L-uncompressed
5982 Image Name: 2.4.4 kernel for TQM850L
5983 Created: Wed Jul 19 02:34:59 2000
5984 Image Type: PowerPC Linux Kernel Image (uncompressed)
5985 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5986 Load Address: 0x00000000
5987 Entry Point: 0x00000000
5990 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5991 when your kernel is intended to use an initial ramdisk:
5993 -> tools/mkimage -n 'Simple Ramdisk Image' \
5994 > -A ppc -O linux -T ramdisk -C gzip \
5995 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5996 Image Name: Simple Ramdisk Image
5997 Created: Wed Jan 12 14:01:50 2000
5998 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5999 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
6000 Load Address: 0x00000000
6001 Entry Point: 0x00000000
6003 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
6004 option performs the converse operation of the mkimage's second form (the "-d"
6005 option). Given an image built by mkimage, the dumpimage extracts a "data file"
6008 tools/dumpimage -i image -T type -p position data_file
6009 -i ==> extract from the 'image' a specific 'data_file'
6010 -T ==> set image type to 'type'
6011 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
6014 Installing a Linux Image:
6015 -------------------------
6017 To downloading a U-Boot image over the serial (console) interface,
6018 you must convert the image to S-Record format:
6020 objcopy -I binary -O srec examples/image examples/image.srec
6022 The 'objcopy' does not understand the information in the U-Boot
6023 image header, so the resulting S-Record file will be relative to
6024 address 0x00000000. To load it to a given address, you need to
6025 specify the target address as 'offset' parameter with the 'loads'
6028 Example: install the image to address 0x40100000 (which on the
6029 TQM8xxL is in the first Flash bank):
6031 => erase 40100000 401FFFFF
6037 ## Ready for S-Record download ...
6038 ~>examples/image.srec
6039 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
6041 15989 15990 15991 15992
6042 [file transfer complete]
6044 ## Start Addr = 0x00000000
6047 You can check the success of the download using the 'iminfo' command;
6048 this includes a checksum verification so you can be sure no data
6049 corruption happened:
6053 ## Checking Image at 40100000 ...
6054 Image Name: 2.2.13 for initrd on TQM850L
6055 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6056 Data Size: 335725 Bytes = 327 kB = 0 MB
6057 Load Address: 00000000
6058 Entry Point: 0000000c
6059 Verifying Checksum ... OK
6065 The "bootm" command is used to boot an application that is stored in
6066 memory (RAM or Flash). In case of a Linux kernel image, the contents
6067 of the "bootargs" environment variable is passed to the kernel as
6068 parameters. You can check and modify this variable using the
6069 "printenv" and "setenv" commands:
6072 => printenv bootargs
6073 bootargs=root=/dev/ram
6075 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6077 => printenv bootargs
6078 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6081 ## Booting Linux kernel at 40020000 ...
6082 Image Name: 2.2.13 for NFS on TQM850L
6083 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6084 Data Size: 381681 Bytes = 372 kB = 0 MB
6085 Load Address: 00000000
6086 Entry Point: 0000000c
6087 Verifying Checksum ... OK
6088 Uncompressing Kernel Image ... OK
6089 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
6090 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6091 time_init: decrementer frequency = 187500000/60
6092 Calibrating delay loop... 49.77 BogoMIPS
6093 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
6096 If you want to boot a Linux kernel with initial RAM disk, you pass
6097 the memory addresses of both the kernel and the initrd image (PPBCOOT
6098 format!) to the "bootm" command:
6100 => imi 40100000 40200000
6102 ## Checking Image at 40100000 ...
6103 Image Name: 2.2.13 for initrd on TQM850L
6104 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6105 Data Size: 335725 Bytes = 327 kB = 0 MB
6106 Load Address: 00000000
6107 Entry Point: 0000000c
6108 Verifying Checksum ... OK
6110 ## Checking Image at 40200000 ...
6111 Image Name: Simple Ramdisk Image
6112 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6113 Data Size: 566530 Bytes = 553 kB = 0 MB
6114 Load Address: 00000000
6115 Entry Point: 00000000
6116 Verifying Checksum ... OK
6118 => bootm 40100000 40200000
6119 ## Booting Linux kernel at 40100000 ...
6120 Image Name: 2.2.13 for initrd on TQM850L
6121 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6122 Data Size: 335725 Bytes = 327 kB = 0 MB
6123 Load Address: 00000000
6124 Entry Point: 0000000c
6125 Verifying Checksum ... OK
6126 Uncompressing Kernel Image ... OK
6127 ## Loading RAMDisk Image at 40200000 ...
6128 Image Name: Simple Ramdisk Image
6129 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6130 Data Size: 566530 Bytes = 553 kB = 0 MB
6131 Load Address: 00000000
6132 Entry Point: 00000000
6133 Verifying Checksum ... OK
6134 Loading Ramdisk ... OK
6135 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
6136 Boot arguments: root=/dev/ram
6137 time_init: decrementer frequency = 187500000/60
6138 Calibrating delay loop... 49.77 BogoMIPS
6140 RAMDISK: Compressed image found at block 0
6141 VFS: Mounted root (ext2 filesystem).
6145 Boot Linux and pass a flat device tree:
6148 First, U-Boot must be compiled with the appropriate defines. See the section
6149 titled "Linux Kernel Interface" above for a more in depth explanation. The
6150 following is an example of how to start a kernel and pass an updated
6156 oft=oftrees/mpc8540ads.dtb
6157 => tftp $oftaddr $oft
6158 Speed: 1000, full duplex
6160 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
6161 Filename 'oftrees/mpc8540ads.dtb'.
6162 Load address: 0x300000
6165 Bytes transferred = 4106 (100a hex)
6166 => tftp $loadaddr $bootfile
6167 Speed: 1000, full duplex
6169 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
6171 Load address: 0x200000
6172 Loading:############
6174 Bytes transferred = 1029407 (fb51f hex)
6179 => bootm $loadaddr - $oftaddr
6180 ## Booting image at 00200000 ...
6181 Image Name: Linux-2.6.17-dirty
6182 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6183 Data Size: 1029343 Bytes = 1005.2 kB
6184 Load Address: 00000000
6185 Entry Point: 00000000
6186 Verifying Checksum ... OK
6187 Uncompressing Kernel Image ... OK
6188 Booting using flat device tree at 0x300000
6189 Using MPC85xx ADS machine description
6190 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
6194 More About U-Boot Image Types:
6195 ------------------------------
6197 U-Boot supports the following image types:
6199 "Standalone Programs" are directly runnable in the environment
6200 provided by U-Boot; it is expected that (if they behave
6201 well) you can continue to work in U-Boot after return from
6202 the Standalone Program.
6203 "OS Kernel Images" are usually images of some Embedded OS which
6204 will take over control completely. Usually these programs
6205 will install their own set of exception handlers, device
6206 drivers, set up the MMU, etc. - this means, that you cannot
6207 expect to re-enter U-Boot except by resetting the CPU.
6208 "RAMDisk Images" are more or less just data blocks, and their
6209 parameters (address, size) are passed to an OS kernel that is
6211 "Multi-File Images" contain several images, typically an OS
6212 (Linux) kernel image and one or more data images like
6213 RAMDisks. This construct is useful for instance when you want
6214 to boot over the network using BOOTP etc., where the boot
6215 server provides just a single image file, but you want to get
6216 for instance an OS kernel and a RAMDisk image.
6218 "Multi-File Images" start with a list of image sizes, each
6219 image size (in bytes) specified by an "uint32_t" in network
6220 byte order. This list is terminated by an "(uint32_t)0".
6221 Immediately after the terminating 0 follow the images, one by
6222 one, all aligned on "uint32_t" boundaries (size rounded up to
6223 a multiple of 4 bytes).
6225 "Firmware Images" are binary images containing firmware (like
6226 U-Boot or FPGA images) which usually will be programmed to
6229 "Script files" are command sequences that will be executed by
6230 U-Boot's command interpreter; this feature is especially
6231 useful when you configure U-Boot to use a real shell (hush)
6232 as command interpreter.
6234 Booting the Linux zImage:
6235 -------------------------
6237 On some platforms, it's possible to boot Linux zImage. This is done
6238 using the "bootz" command. The syntax of "bootz" command is the same
6239 as the syntax of "bootm" command.
6241 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
6242 kernel with raw initrd images. The syntax is slightly different, the
6243 address of the initrd must be augmented by it's size, in the following
6244 format: "<initrd addres>:<initrd size>".
6250 One of the features of U-Boot is that you can dynamically load and
6251 run "standalone" applications, which can use some resources of
6252 U-Boot like console I/O functions or interrupt services.
6254 Two simple examples are included with the sources:
6259 'examples/hello_world.c' contains a small "Hello World" Demo
6260 application; it is automatically compiled when you build U-Boot.
6261 It's configured to run at address 0x00040004, so you can play with it
6265 ## Ready for S-Record download ...
6266 ~>examples/hello_world.srec
6267 1 2 3 4 5 6 7 8 9 10 11 ...
6268 [file transfer complete]
6270 ## Start Addr = 0x00040004
6272 => go 40004 Hello World! This is a test.
6273 ## Starting application at 0x00040004 ...
6284 Hit any key to exit ...
6286 ## Application terminated, rc = 0x0
6288 Another example, which demonstrates how to register a CPM interrupt
6289 handler with the U-Boot code, can be found in 'examples/timer.c'.
6290 Here, a CPM timer is set up to generate an interrupt every second.
6291 The interrupt service routine is trivial, just printing a '.'
6292 character, but this is just a demo program. The application can be
6293 controlled by the following keys:
6295 ? - print current values og the CPM Timer registers
6296 b - enable interrupts and start timer
6297 e - stop timer and disable interrupts
6298 q - quit application
6301 ## Ready for S-Record download ...
6302 ~>examples/timer.srec
6303 1 2 3 4 5 6 7 8 9 10 11 ...
6304 [file transfer complete]
6306 ## Start Addr = 0x00040004
6309 ## Starting application at 0x00040004 ...
6312 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6315 [q, b, e, ?] Set interval 1000000 us
6318 [q, b, e, ?] ........
6319 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6322 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6325 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6328 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6330 [q, b, e, ?] ...Stopping timer
6332 [q, b, e, ?] ## Application terminated, rc = 0x0
6338 Over time, many people have reported problems when trying to use the
6339 "minicom" terminal emulation program for serial download. I (wd)
6340 consider minicom to be broken, and recommend not to use it. Under
6341 Unix, I recommend to use C-Kermit for general purpose use (and
6342 especially for kermit binary protocol download ("loadb" command), and
6343 use "cu" for S-Record download ("loads" command). See
6344 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6345 for help with kermit.
6348 Nevertheless, if you absolutely want to use it try adding this
6349 configuration to your "File transfer protocols" section:
6351 Name Program Name U/D FullScr IO-Red. Multi
6352 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6353 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6359 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6360 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6362 Building requires a cross environment; it is known to work on
6363 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6364 need gmake since the Makefiles are not compatible with BSD make).
6365 Note that the cross-powerpc package does not install include files;
6366 attempting to build U-Boot will fail because <machine/ansi.h> is
6367 missing. This file has to be installed and patched manually:
6369 # cd /usr/pkg/cross/powerpc-netbsd/include
6371 # ln -s powerpc machine
6372 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6373 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6375 Native builds *don't* work due to incompatibilities between native
6376 and U-Boot include files.
6378 Booting assumes that (the first part of) the image booted is a
6379 stage-2 loader which in turn loads and then invokes the kernel
6380 proper. Loader sources will eventually appear in the NetBSD source
6381 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6382 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6385 Implementation Internals:
6386 =========================
6388 The following is not intended to be a complete description of every
6389 implementation detail. However, it should help to understand the
6390 inner workings of U-Boot and make it easier to port it to custom
6394 Initial Stack, Global Data:
6395 ---------------------------
6397 The implementation of U-Boot is complicated by the fact that U-Boot
6398 starts running out of ROM (flash memory), usually without access to
6399 system RAM (because the memory controller is not initialized yet).
6400 This means that we don't have writable Data or BSS segments, and BSS
6401 is not initialized as zero. To be able to get a C environment working
6402 at all, we have to allocate at least a minimal stack. Implementation
6403 options for this are defined and restricted by the CPU used: Some CPU
6404 models provide on-chip memory (like the IMMR area on MPC8xx and
6405 MPC826x processors), on others (parts of) the data cache can be
6406 locked as (mis-) used as memory, etc.
6408 Chris Hallinan posted a good summary of these issues to the
6409 U-Boot mailing list:
6411 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6412 From: "Chris Hallinan" <clh@net1plus.com>
6413 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6416 Correct me if I'm wrong, folks, but the way I understand it
6417 is this: Using DCACHE as initial RAM for Stack, etc, does not
6418 require any physical RAM backing up the cache. The cleverness
6419 is that the cache is being used as a temporary supply of
6420 necessary storage before the SDRAM controller is setup. It's
6421 beyond the scope of this list to explain the details, but you
6422 can see how this works by studying the cache architecture and
6423 operation in the architecture and processor-specific manuals.
6425 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6426 is another option for the system designer to use as an
6427 initial stack/RAM area prior to SDRAM being available. Either
6428 option should work for you. Using CS 4 should be fine if your
6429 board designers haven't used it for something that would
6430 cause you grief during the initial boot! It is frequently not
6433 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6434 with your processor/board/system design. The default value
6435 you will find in any recent u-boot distribution in
6436 walnut.h should work for you. I'd set it to a value larger
6437 than your SDRAM module. If you have a 64MB SDRAM module, set
6438 it above 400_0000. Just make sure your board has no resources
6439 that are supposed to respond to that address! That code in
6440 start.S has been around a while and should work as is when
6441 you get the config right.
6446 It is essential to remember this, since it has some impact on the C
6447 code for the initialization procedures:
6449 * Initialized global data (data segment) is read-only. Do not attempt
6452 * Do not use any uninitialized global data (or implicitly initialized
6453 as zero data - BSS segment) at all - this is undefined, initiali-
6454 zation is performed later (when relocating to RAM).
6456 * Stack space is very limited. Avoid big data buffers or things like
6459 Having only the stack as writable memory limits means we cannot use
6460 normal global data to share information between the code. But it
6461 turned out that the implementation of U-Boot can be greatly
6462 simplified by making a global data structure (gd_t) available to all
6463 functions. We could pass a pointer to this data as argument to _all_
6464 functions, but this would bloat the code. Instead we use a feature of
6465 the GCC compiler (Global Register Variables) to share the data: we
6466 place a pointer (gd) to the global data into a register which we
6467 reserve for this purpose.
6469 When choosing a register for such a purpose we are restricted by the
6470 relevant (E)ABI specifications for the current architecture, and by
6471 GCC's implementation.
6473 For PowerPC, the following registers have specific use:
6475 R2: reserved for system use
6476 R3-R4: parameter passing and return values
6477 R5-R10: parameter passing
6478 R13: small data area pointer
6482 (U-Boot also uses R12 as internal GOT pointer. r12
6483 is a volatile register so r12 needs to be reset when
6484 going back and forth between asm and C)
6486 ==> U-Boot will use R2 to hold a pointer to the global data
6488 Note: on PPC, we could use a static initializer (since the
6489 address of the global data structure is known at compile time),
6490 but it turned out that reserving a register results in somewhat
6491 smaller code - although the code savings are not that big (on
6492 average for all boards 752 bytes for the whole U-Boot image,
6493 624 text + 127 data).
6495 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6496 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6498 ==> U-Boot will use P3 to hold a pointer to the global data
6500 On ARM, the following registers are used:
6502 R0: function argument word/integer result
6503 R1-R3: function argument word
6504 R9: platform specific
6505 R10: stack limit (used only if stack checking is enabled)
6506 R11: argument (frame) pointer
6507 R12: temporary workspace
6510 R15: program counter
6512 ==> U-Boot will use R9 to hold a pointer to the global data
6514 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6516 On Nios II, the ABI is documented here:
6517 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6519 ==> U-Boot will use gp to hold a pointer to the global data
6521 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6522 to access small data sections, so gp is free.
6524 On NDS32, the following registers are used:
6526 R0-R1: argument/return
6528 R15: temporary register for assembler
6529 R16: trampoline register
6530 R28: frame pointer (FP)
6531 R29: global pointer (GP)
6532 R30: link register (LP)
6533 R31: stack pointer (SP)
6534 PC: program counter (PC)
6536 ==> U-Boot will use R10 to hold a pointer to the global data
6538 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6539 or current versions of GCC may "optimize" the code too much.
6544 U-Boot runs in system state and uses physical addresses, i.e. the
6545 MMU is not used either for address mapping nor for memory protection.
6547 The available memory is mapped to fixed addresses using the memory
6548 controller. In this process, a contiguous block is formed for each
6549 memory type (Flash, SDRAM, SRAM), even when it consists of several
6550 physical memory banks.
6552 U-Boot is installed in the first 128 kB of the first Flash bank (on
6553 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6554 booting and sizing and initializing DRAM, the code relocates itself
6555 to the upper end of DRAM. Immediately below the U-Boot code some
6556 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6557 configuration setting]. Below that, a structure with global Board
6558 Info data is placed, followed by the stack (growing downward).
6560 Additionally, some exception handler code is copied to the low 8 kB
6561 of DRAM (0x00000000 ... 0x00001FFF).
6563 So a typical memory configuration with 16 MB of DRAM could look like
6566 0x0000 0000 Exception Vector code
6569 0x0000 2000 Free for Application Use
6575 0x00FB FF20 Monitor Stack (Growing downward)
6576 0x00FB FFAC Board Info Data and permanent copy of global data
6577 0x00FC 0000 Malloc Arena
6580 0x00FE 0000 RAM Copy of Monitor Code
6581 ... eventually: LCD or video framebuffer
6582 ... eventually: pRAM (Protected RAM - unchanged by reset)
6583 0x00FF FFFF [End of RAM]
6586 System Initialization:
6587 ----------------------
6589 In the reset configuration, U-Boot starts at the reset entry point
6590 (on most PowerPC systems at address 0x00000100). Because of the reset
6591 configuration for CS0# this is a mirror of the on board Flash memory.
6592 To be able to re-map memory U-Boot then jumps to its link address.
6593 To be able to implement the initialization code in C, a (small!)
6594 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6595 which provide such a feature like MPC8xx or MPC8260), or in a locked
6596 part of the data cache. After that, U-Boot initializes the CPU core,
6597 the caches and the SIU.
6599 Next, all (potentially) available memory banks are mapped using a
6600 preliminary mapping. For example, we put them on 512 MB boundaries
6601 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6602 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6603 programmed for SDRAM access. Using the temporary configuration, a
6604 simple memory test is run that determines the size of the SDRAM
6607 When there is more than one SDRAM bank, and the banks are of
6608 different size, the largest is mapped first. For equal size, the first
6609 bank (CS2#) is mapped first. The first mapping is always for address
6610 0x00000000, with any additional banks following immediately to create
6611 contiguous memory starting from 0.
6613 Then, the monitor installs itself at the upper end of the SDRAM area
6614 and allocates memory for use by malloc() and for the global Board
6615 Info data; also, the exception vector code is copied to the low RAM
6616 pages, and the final stack is set up.
6618 Only after this relocation will you have a "normal" C environment;
6619 until that you are restricted in several ways, mostly because you are
6620 running from ROM, and because the code will have to be relocated to a
6624 U-Boot Porting Guide:
6625 ----------------------
6627 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6631 int main(int argc, char *argv[])
6633 sighandler_t no_more_time;
6635 signal(SIGALRM, no_more_time);
6636 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6638 if (available_money > available_manpower) {
6639 Pay consultant to port U-Boot;
6643 Download latest U-Boot source;
6645 Subscribe to u-boot mailing list;
6648 email("Hi, I am new to U-Boot, how do I get started?");
6651 Read the README file in the top level directory;
6652 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6653 Read applicable doc/*.README;
6654 Read the source, Luke;
6655 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6658 if (available_money > toLocalCurrency ($2500))
6661 Add a lot of aggravation and time;
6663 if (a similar board exists) { /* hopefully... */
6664 cp -a board/<similar> board/<myboard>
6665 cp include/configs/<similar>.h include/configs/<myboard>.h
6667 Create your own board support subdirectory;
6668 Create your own board include/configs/<myboard>.h file;
6670 Edit new board/<myboard> files
6671 Edit new include/configs/<myboard>.h
6676 Add / modify source code;
6680 email("Hi, I am having problems...");
6682 Send patch file to the U-Boot email list;
6683 if (reasonable critiques)
6684 Incorporate improvements from email list code review;
6686 Defend code as written;
6692 void no_more_time (int sig)
6701 All contributions to U-Boot should conform to the Linux kernel
6702 coding style; see the file "Documentation/CodingStyle" and the script
6703 "scripts/Lindent" in your Linux kernel source directory.
6705 Source files originating from a different project (for example the
6706 MTD subsystem) are generally exempt from these guidelines and are not
6707 reformatted to ease subsequent migration to newer versions of those
6710 Please note that U-Boot is implemented in C (and to some small parts in
6711 Assembler); no C++ is used, so please do not use C++ style comments (//)
6714 Please also stick to the following formatting rules:
6715 - remove any trailing white space
6716 - use TAB characters for indentation and vertical alignment, not spaces
6717 - make sure NOT to use DOS '\r\n' line feeds
6718 - do not add more than 2 consecutive empty lines to source files
6719 - do not add trailing empty lines to source files
6721 Submissions which do not conform to the standards may be returned
6722 with a request to reformat the changes.
6728 Since the number of patches for U-Boot is growing, we need to
6729 establish some rules. Submissions which do not conform to these rules
6730 may be rejected, even when they contain important and valuable stuff.
6732 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6734 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6735 see http://lists.denx.de/mailman/listinfo/u-boot
6737 When you send a patch, please include the following information with
6740 * For bug fixes: a description of the bug and how your patch fixes
6741 this bug. Please try to include a way of demonstrating that the
6742 patch actually fixes something.
6744 * For new features: a description of the feature and your
6747 * A CHANGELOG entry as plaintext (separate from the patch)
6749 * For major contributions, your entry to the CREDITS file
6751 * When you add support for a new board, don't forget to add a
6752 maintainer e-mail address to the boards.cfg file, too.
6754 * If your patch adds new configuration options, don't forget to
6755 document these in the README file.
6757 * The patch itself. If you are using git (which is *strongly*
6758 recommended) you can easily generate the patch using the
6759 "git format-patch". If you then use "git send-email" to send it to
6760 the U-Boot mailing list, you will avoid most of the common problems
6761 with some other mail clients.
6763 If you cannot use git, use "diff -purN OLD NEW". If your version of
6764 diff does not support these options, then get the latest version of
6767 The current directory when running this command shall be the parent
6768 directory of the U-Boot source tree (i. e. please make sure that
6769 your patch includes sufficient directory information for the
6772 We prefer patches as plain text. MIME attachments are discouraged,
6773 and compressed attachments must not be used.
6775 * If one logical set of modifications affects or creates several
6776 files, all these changes shall be submitted in a SINGLE patch file.
6778 * Changesets that contain different, unrelated modifications shall be
6779 submitted as SEPARATE patches, one patch per changeset.
6784 * Before sending the patch, run the MAKEALL script on your patched
6785 source tree and make sure that no errors or warnings are reported
6786 for any of the boards.
6788 * Keep your modifications to the necessary minimum: A patch
6789 containing several unrelated changes or arbitrary reformats will be
6790 returned with a request to re-formatting / split it.
6792 * If you modify existing code, make sure that your new code does not
6793 add to the memory footprint of the code ;-) Small is beautiful!
6794 When adding new features, these should compile conditionally only
6795 (using #ifdef), and the resulting code with the new feature
6796 disabled must not need more memory than the old code without your
6799 * Remember that there is a size limit of 100 kB per message on the
6800 u-boot mailing list. Bigger patches will be moderated. If they are
6801 reasonable and not too big, they will be acknowledged. But patches
6802 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob