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 file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /blackfin Files generic to Analog Devices Blackfin architecture
141 /m68k Files generic to m68k architecture
142 /microblaze Files generic to microblaze architecture
143 /mips Files generic to MIPS architecture
144 /nds32 Files generic to NDS32 architecture
145 /nios2 Files generic to Altera NIOS2 architecture
146 /openrisc Files generic to OpenRISC architecture
147 /powerpc Files generic to PowerPC architecture
148 /sandbox Files generic to HW-independent "sandbox"
149 /sh Files generic to SH architecture
150 /sparc Files generic to SPARC architecture
151 /x86 Files generic to x86 architecture
152 /api Machine/arch independent API for external apps
153 /board Board dependent files
154 /cmd U-Boot commands functions
155 /common Misc architecture independent functions
156 /configs Board default configuration files
157 /disk Code for disk drive partition handling
158 /doc Documentation (don't expect too much)
159 /drivers Commonly used device drivers
160 /dts Contains Makefile for building internal U-Boot fdt.
161 /examples Example code for standalone applications, etc.
162 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
163 /include Header Files
164 /lib Library routines generic to all architectures
165 /Licenses Various license files
167 /post Power On Self Test
168 /scripts Various build scripts and Makefiles
169 /test Various unit test files
170 /tools Tools to build S-Record or U-Boot images, etc.
172 Software Configuration:
173 =======================
175 Configuration is usually done using C preprocessor defines; the
176 rationale behind that is to avoid dead code whenever possible.
178 There are two classes of configuration variables:
180 * Configuration _OPTIONS_:
181 These are selectable by the user and have names beginning with
184 * Configuration _SETTINGS_:
185 These depend on the hardware etc. and should not be meddled with if
186 you don't know what you're doing; they have names beginning with
189 Previously, all configuration was done by hand, which involved creating
190 symbolic links and editing configuration files manually. More recently,
191 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
192 allowing you to use the "make menuconfig" command to configure your
196 Selection of Processor Architecture and Board Type:
197 ---------------------------------------------------
199 For all supported boards there are ready-to-use default
200 configurations available; just type "make <board_name>_defconfig".
202 Example: For a TQM823L module type:
205 make TQM823L_defconfig
207 Note: If you're looking for the default configuration file for a board
208 you're sure used to be there but is now missing, check the file
209 doc/README.scrapyard for a list of no longer supported boards.
214 U-Boot can be built natively to run on a Linux host using the 'sandbox'
215 board. This allows feature development which is not board- or architecture-
216 specific to be undertaken on a native platform. The sandbox is also used to
217 run some of U-Boot's tests.
219 See board/sandbox/README.sandbox for more details.
222 Board Initialisation Flow:
223 --------------------------
225 This is the intended start-up flow for boards. This should apply for both
226 SPL and U-Boot proper (i.e. they both follow the same rules).
228 Note: "SPL" stands for "Secondary Program Loader," which is explained in
229 more detail later in this file.
231 At present, SPL mostly uses a separate code path, but the function names
232 and roles of each function are the same. Some boards or architectures
233 may not conform to this. At least most ARM boards which use
234 CONFIG_SPL_FRAMEWORK conform to this.
236 Execution typically starts with an architecture-specific (and possibly
237 CPU-specific) start.S file, such as:
239 - arch/arm/cpu/armv7/start.S
240 - arch/powerpc/cpu/mpc83xx/start.S
241 - arch/mips/cpu/start.S
243 and so on. From there, three functions are called; the purpose and
244 limitations of each of these functions are described below.
247 - purpose: essential init to permit execution to reach board_init_f()
248 - no global_data or BSS
249 - there is no stack (ARMv7 may have one but it will soon be removed)
250 - must not set up SDRAM or use console
251 - must only do the bare minimum to allow execution to continue to
253 - this is almost never needed
254 - return normally from this function
257 - purpose: set up the machine ready for running board_init_r():
258 i.e. SDRAM and serial UART
259 - global_data is available
261 - BSS is not available, so you cannot use global/static variables,
262 only stack variables and global_data
264 Non-SPL-specific notes:
265 - dram_init() is called to set up DRAM. If already done in SPL this
269 - you can override the entire board_init_f() function with your own
271 - preloader_console_init() can be called here in extremis
272 - should set up SDRAM, and anything needed to make the UART work
273 - these is no need to clear BSS, it will be done by crt0.S
274 - must return normally from this function (don't call board_init_r()
277 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
278 this point the stack and global_data are relocated to below
279 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
283 - purpose: main execution, common code
284 - global_data is available
286 - BSS is available, all static/global variables can be used
287 - execution eventually continues to main_loop()
289 Non-SPL-specific notes:
290 - U-Boot is relocated to the top of memory and is now running from
294 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
295 CONFIG_SPL_STACK_R_ADDR points into SDRAM
296 - preloader_console_init() can be called here - typically this is
297 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
298 spl_board_init() function containing this call
299 - loads U-Boot or (in falcon mode) Linux
303 Configuration Options:
304 ----------------------
306 Configuration depends on the combination of board and CPU type; all
307 such information is kept in a configuration file
308 "include/configs/<board_name>.h".
310 Example: For a TQM823L module, all configuration settings are in
311 "include/configs/TQM823L.h".
314 Many of the options are named exactly as the corresponding Linux
315 kernel configuration options. The intention is to make it easier to
316 build a config tool - later.
319 The following options need to be configured:
321 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
323 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
325 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
326 Define exactly one, e.g. CONFIG_ATSTK1002
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_PPC_E500_DEBUG_TLB
381 Enables a temporary TLB entry to be used during boot to work
382 around limitations in e500v1 and e500v2 external debugger
383 support. This reduces the portions of the boot code where
384 breakpoints and single stepping do not work. The value of this
385 symbol should be set to the TLB1 entry to be used for this
388 CONFIG_SYS_FSL_ERRATUM_A004510
390 Enables a workaround for erratum A004510. If set,
391 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
394 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
397 Defines one or two SoC revisions (low 8 bits of SVR)
398 for which the A004510 workaround should be applied.
400 The rest of SVR is either not relevant to the decision
401 of whether the erratum is present (e.g. p2040 versus
402 p2041) or is implied by the build target, which controls
403 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
405 See Freescale App Note 4493 for more information about
408 CONFIG_A003399_NOR_WORKAROUND
409 Enables a workaround for IFC erratum A003399. It is only
410 required during NOR boot.
412 CONFIG_A008044_WORKAROUND
413 Enables a workaround for T1040/T1042 erratum A008044. It is only
414 required during NAND boot and valid for Rev 1.0 SoC revision
416 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
418 This is the value to write into CCSR offset 0x18600
419 according to the A004510 workaround.
421 CONFIG_SYS_FSL_DSP_DDR_ADDR
422 This value denotes start offset of DDR memory which is
423 connected exclusively to the DSP cores.
425 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
426 This value denotes start offset of M2 memory
427 which is directly connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
430 This value denotes start offset of M3 memory which is directly
431 connected to the DSP core.
433 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
434 This value denotes start offset of DSP CCSR space.
436 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
437 Single Source Clock is clocking mode present in some of FSL SoC's.
438 In this mode, a single differential clock is used to supply
439 clocks to the sysclock, ddrclock and usbclock.
441 CONFIG_SYS_CPC_REINIT_F
442 This CONFIG is defined when the CPC is configured as SRAM at the
443 time of U-Boot entry and is required to be re-initialized.
446 Indicates this SoC supports deep sleep feature. If deep sleep is
447 supported, core will start to execute uboot when wakes up.
449 - Generic CPU options:
450 CONFIG_SYS_GENERIC_GLOBAL_DATA
451 Defines global data is initialized in generic board board_init_f().
452 If this macro is defined, global data is created and cleared in
453 generic board board_init_f(). Without this macro, architecture/board
454 should initialize global data before calling board_init_f().
456 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
458 Defines the endianess of the CPU. Implementation of those
459 values is arch specific.
462 Freescale DDR driver in use. This type of DDR controller is
463 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
466 CONFIG_SYS_FSL_DDR_ADDR
467 Freescale DDR memory-mapped register base.
469 CONFIG_SYS_FSL_DDR_EMU
470 Specify emulator support for DDR. Some DDR features such as
471 deskew training are not available.
473 CONFIG_SYS_FSL_DDRC_GEN1
474 Freescale DDR1 controller.
476 CONFIG_SYS_FSL_DDRC_GEN2
477 Freescale DDR2 controller.
479 CONFIG_SYS_FSL_DDRC_GEN3
480 Freescale DDR3 controller.
482 CONFIG_SYS_FSL_DDRC_GEN4
483 Freescale DDR4 controller.
485 CONFIG_SYS_FSL_DDRC_ARM_GEN3
486 Freescale DDR3 controller for ARM-based SoCs.
489 Board config to use DDR1. It can be enabled for SoCs with
490 Freescale DDR1 or DDR2 controllers, depending on the board
494 Board config to use DDR2. It can be enabled for SoCs with
495 Freescale DDR2 or DDR3 controllers, depending on the board
499 Board config to use DDR3. It can be enabled for SoCs with
500 Freescale DDR3 or DDR3L controllers.
503 Board config to use DDR3L. It can be enabled for SoCs with
507 Board config to use DDR4. It can be enabled for SoCs with
510 CONFIG_SYS_FSL_IFC_BE
511 Defines the IFC controller register space as Big Endian
513 CONFIG_SYS_FSL_IFC_LE
514 Defines the IFC controller register space as Little Endian
516 CONFIG_SYS_FSL_PBL_PBI
517 It enables addition of RCW (Power on reset configuration) in built image.
518 Please refer doc/README.pblimage for more details
520 CONFIG_SYS_FSL_PBL_RCW
521 It adds PBI(pre-boot instructions) commands in u-boot build image.
522 PBI commands can be used to configure SoC before it starts the execution.
523 Please refer doc/README.pblimage for more details
526 It adds a target to create boot binary having SPL binary in PBI format
527 concatenated with u-boot binary.
529 CONFIG_SYS_FSL_DDR_BE
530 Defines the DDR controller register space as Big Endian
532 CONFIG_SYS_FSL_DDR_LE
533 Defines the DDR controller register space as Little Endian
535 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
536 Physical address from the view of DDR controllers. It is the
537 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
538 it could be different for ARM SoCs.
540 CONFIG_SYS_FSL_DDR_INTLV_256B
541 DDR controller interleaving on 256-byte. This is a special
542 interleaving mode, handled by Dickens for Freescale layerscape
545 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
546 Number of controllers used as main memory.
548 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
549 Number of controllers used for other than main memory.
551 CONFIG_SYS_FSL_HAS_DP_DDR
552 Defines the SoC has DP-DDR used for DPAA.
554 CONFIG_SYS_FSL_SEC_BE
555 Defines the SEC controller register space as Big Endian
557 CONFIG_SYS_FSL_SEC_LE
558 Defines the SEC controller register space as Little Endian
561 CONFIG_SYS_INIT_SP_OFFSET
563 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
564 pointer. This is needed for the temporary stack before
567 CONFIG_SYS_MIPS_CACHE_MODE
569 Cache operation mode for the MIPS CPU.
570 See also arch/mips/include/asm/mipsregs.h.
572 CONF_CM_CACHABLE_NO_WA
575 CONF_CM_CACHABLE_NONCOHERENT
579 CONF_CM_CACHABLE_ACCELERATED
581 CONFIG_SYS_XWAY_EBU_BOOTCFG
583 Special option for Lantiq XWAY SoCs for booting from NOR flash.
584 See also arch/mips/cpu/mips32/start.S.
586 CONFIG_XWAY_SWAP_BYTES
588 Enable compilation of tools/xway-swap-bytes needed for Lantiq
589 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
590 be swapped if a flash programmer is used.
593 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
595 Select high exception vectors of the ARM core, e.g., do not
596 clear the V bit of the c1 register of CP15.
598 CONFIG_SYS_THUMB_BUILD
600 Use this flag to build U-Boot using the Thumb instruction
601 set for ARM architectures. Thumb instruction set provides
602 better code density. For ARM architectures that support
603 Thumb2 this flag will result in Thumb2 code generated by
606 CONFIG_ARM_ERRATA_716044
607 CONFIG_ARM_ERRATA_742230
608 CONFIG_ARM_ERRATA_743622
609 CONFIG_ARM_ERRATA_751472
610 CONFIG_ARM_ERRATA_761320
611 CONFIG_ARM_ERRATA_773022
612 CONFIG_ARM_ERRATA_774769
613 CONFIG_ARM_ERRATA_794072
615 If set, the workarounds for these ARM errata are applied early
616 during U-Boot startup. Note that these options force the
617 workarounds to be applied; no CPU-type/version detection
618 exists, unlike the similar options in the Linux kernel. Do not
619 set these options unless they apply!
622 Generic timer clock source frequency.
624 COUNTER_FREQUENCY_REAL
625 Generic timer clock source frequency if the real clock is
626 different from COUNTER_FREQUENCY, and can only be determined
629 NOTE: The following can be machine specific errata. These
630 do have ability to provide rudimentary version and machine
631 specific checks, but expect no product checks.
632 CONFIG_ARM_ERRATA_430973
633 CONFIG_ARM_ERRATA_454179
634 CONFIG_ARM_ERRATA_621766
635 CONFIG_ARM_ERRATA_798870
636 CONFIG_ARM_ERRATA_801819
639 CONFIG_TEGRA_SUPPORT_NON_SECURE
641 Support executing U-Boot in non-secure (NS) mode. Certain
642 impossible actions will be skipped if the CPU is in NS mode,
643 such as ARM architectural timer initialization.
645 - Linux Kernel Interface:
648 U-Boot stores all clock information in Hz
649 internally. For binary compatibility with older Linux
650 kernels (which expect the clocks passed in the
651 bd_info data to be in MHz) the environment variable
652 "clocks_in_mhz" can be defined so that U-Boot
653 converts clock data to MHZ before passing it to the
655 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
656 "clocks_in_mhz=1" is automatically included in the
659 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
661 When transferring memsize parameter to Linux, some versions
662 expect it to be in bytes, others in MB.
663 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
667 New kernel versions are expecting firmware settings to be
668 passed using flattened device trees (based on open firmware
672 * New libfdt-based support
673 * Adds the "fdt" command
674 * The bootm command automatically updates the fdt
676 OF_CPU - The proper name of the cpus node (only required for
677 MPC512X and MPC5xxx based boards).
678 OF_SOC - The proper name of the soc node (only required for
679 MPC512X and MPC5xxx based boards).
680 OF_TBCLK - The timebase frequency.
681 OF_STDOUT_PATH - The path to the console device
683 boards with QUICC Engines require OF_QE to set UCC MAC
686 CONFIG_OF_BOARD_SETUP
688 Board code has addition modification that it wants to make
689 to the flat device tree before handing it off to the kernel
691 CONFIG_OF_SYSTEM_SETUP
693 Other code has addition modification that it wants to make
694 to the flat device tree before handing it off to the kernel.
695 This causes ft_system_setup() to be called before booting
700 U-Boot can detect if an IDE device is present or not.
701 If not, and this new config option is activated, U-Boot
702 removes the ATA node from the DTS before booting Linux,
703 so the Linux IDE driver does not probe the device and
704 crash. This is needed for buggy hardware (uc101) where
705 no pull down resistor is connected to the signal IDE5V_DD7.
707 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
709 This setting is mandatory for all boards that have only one
710 machine type and must be used to specify the machine type
711 number as it appears in the ARM machine registry
712 (see http://www.arm.linux.org.uk/developer/machines/).
713 Only boards that have multiple machine types supported
714 in a single configuration file and the machine type is
715 runtime discoverable, do not have to use this setting.
717 - vxWorks boot parameters:
719 bootvx constructs a valid bootline using the following
720 environments variables: bootdev, bootfile, ipaddr, netmask,
721 serverip, gatewayip, hostname, othbootargs.
722 It loads the vxWorks image pointed bootfile.
724 Note: If a "bootargs" environment is defined, it will overwride
725 the defaults discussed just above.
727 - Cache Configuration:
728 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
729 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
730 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
732 - Cache Configuration for ARM:
733 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
735 CONFIG_SYS_PL310_BASE - Physical base address of PL310
736 controller register space
741 Define this if you want support for Amba PrimeCell PL010 UARTs.
745 Define this if you want support for Amba PrimeCell PL011 UARTs.
749 If you have Amba PrimeCell PL011 UARTs, set this variable to
750 the clock speed of the UARTs.
754 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
755 define this to a list of base addresses for each (supported)
756 port. See e.g. include/configs/versatile.h
758 CONFIG_SERIAL_HW_FLOW_CONTROL
760 Define this variable to enable hw flow control in serial driver.
761 Current user of this option is drivers/serial/nsl16550.c driver
764 Depending on board, define exactly one serial port
765 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
766 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
767 console by defining CONFIG_8xx_CONS_NONE
769 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
770 port routines must be defined elsewhere
771 (i.e. serial_init(), serial_getc(), ...)
773 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
775 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
779 CONFIG_BAUDRATE - in bps
780 Select one of the baudrates listed in
781 CONFIG_SYS_BAUDRATE_TABLE, see below.
782 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
784 - Console Rx buffer length
785 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
786 the maximum receive buffer length for the SMC.
787 This option is actual only for 82xx and 8xx possible.
788 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
789 must be defined, to setup the maximum idle timeout for
794 Only needed when CONFIG_BOOTDELAY is enabled;
795 define a command string that is automatically executed
796 when no character is read on the console interface
797 within "Boot Delay" after reset.
800 This can be used to pass arguments to the bootm
801 command. The value of CONFIG_BOOTARGS goes into the
802 environment value "bootargs".
804 CONFIG_RAMBOOT and CONFIG_NFSBOOT
805 The value of these goes into the environment as
806 "ramboot" and "nfsboot" respectively, and can be used
807 as a convenience, when switching between booting from
811 CONFIG_BOOTCOUNT_LIMIT
812 Implements a mechanism for detecting a repeating reboot
814 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
817 If no softreset save registers are found on the hardware
818 "bootcount" is stored in the environment. To prevent a
819 saveenv on all reboots, the environment variable
820 "upgrade_available" is used. If "upgrade_available" is
821 0, "bootcount" is always 0, if "upgrade_available" is
822 1 "bootcount" is incremented in the environment.
823 So the Userspace Applikation must set the "upgrade_available"
824 and "bootcount" variable to 0, if a boot was successfully.
829 When this option is #defined, the existence of the
830 environment variable "preboot" will be checked
831 immediately before starting the CONFIG_BOOTDELAY
832 countdown and/or running the auto-boot command resp.
833 entering interactive mode.
835 This feature is especially useful when "preboot" is
836 automatically generated or modified. For an example
837 see the LWMON board specific code: here "preboot" is
838 modified when the user holds down a certain
839 combination of keys on the (special) keyboard when
842 - Serial Download Echo Mode:
844 If defined to 1, all characters received during a
845 serial download (using the "loads" command) are
846 echoed back. This might be needed by some terminal
847 emulations (like "cu"), but may as well just take
848 time on others. This setting #define's the initial
849 value of the "loads_echo" environment variable.
851 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
853 Select one of the baudrates listed in
854 CONFIG_SYS_BAUDRATE_TABLE, see below.
857 Monitor commands can be included or excluded
858 from the build by using the #include files
859 <config_cmd_all.h> and #undef'ing unwanted
860 commands, or adding #define's for wanted commands.
862 The default command configuration includes all commands
863 except those marked below with a "*".
865 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
866 CONFIG_CMD_ASKENV * ask for env variable
867 CONFIG_CMD_BDI bdinfo
868 CONFIG_CMD_BEDBUG * Include BedBug Debugger
869 CONFIG_CMD_BMP * BMP support
870 CONFIG_CMD_BSP * Board specific commands
871 CONFIG_CMD_BOOTD bootd
872 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
873 CONFIG_CMD_CACHE * icache, dcache
874 CONFIG_CMD_CLK * clock command support
875 CONFIG_CMD_CONSOLE coninfo
876 CONFIG_CMD_CRC32 * crc32
877 CONFIG_CMD_DATE * support for RTC, date/time...
878 CONFIG_CMD_DHCP * DHCP support
879 CONFIG_CMD_DIAG * Diagnostics
880 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
881 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
882 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
883 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
884 CONFIG_CMD_DTT * Digital Therm and Thermostat
885 CONFIG_CMD_ECHO echo arguments
886 CONFIG_CMD_EDITENV edit env variable
887 CONFIG_CMD_EEPROM * EEPROM read/write support
888 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
889 CONFIG_CMD_ELF * bootelf, bootvx
890 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
891 CONFIG_CMD_ENV_FLAGS * display details about env flags
892 CONFIG_CMD_ENV_EXISTS * check existence of env variable
893 CONFIG_CMD_EXPORTENV * export the environment
894 CONFIG_CMD_EXT2 * ext2 command support
895 CONFIG_CMD_EXT4 * ext4 command support
896 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
897 that work for multiple fs types
898 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
899 CONFIG_CMD_SAVEENV saveenv
900 CONFIG_CMD_FDC * Floppy Disk Support
901 CONFIG_CMD_FAT * FAT command support
902 CONFIG_CMD_FLASH flinfo, erase, protect
903 CONFIG_CMD_FPGA FPGA device initialization support
904 CONFIG_CMD_FUSE * Device fuse support
905 CONFIG_CMD_GETTIME * Get time since boot
906 CONFIG_CMD_GO * the 'go' command (exec code)
907 CONFIG_CMD_GREPENV * search environment
908 CONFIG_CMD_HASH * calculate hash / digest
909 CONFIG_CMD_I2C * I2C serial bus support
910 CONFIG_CMD_IDE * IDE harddisk support
911 CONFIG_CMD_IMI iminfo
912 CONFIG_CMD_IMLS List all images found in NOR flash
913 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
914 CONFIG_CMD_IMMAP * IMMR dump support
915 CONFIG_CMD_IOTRACE * I/O tracing for debugging
916 CONFIG_CMD_IMPORTENV * import an environment
917 CONFIG_CMD_INI * import data from an ini file into the env
918 CONFIG_CMD_IRQ * irqinfo
919 CONFIG_CMD_ITEST Integer/string test of 2 values
920 CONFIG_CMD_JFFS2 * JFFS2 Support
921 CONFIG_CMD_KGDB * kgdb
922 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
923 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
925 CONFIG_CMD_LOADB loadb
926 CONFIG_CMD_LOADS loads
927 CONFIG_CMD_MD5SUM * print md5 message digest
928 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
929 CONFIG_CMD_MEMINFO * Display detailed memory information
930 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
932 CONFIG_CMD_MEMTEST * mtest
933 CONFIG_CMD_MISC Misc functions like sleep etc
934 CONFIG_CMD_MMC * MMC memory mapped support
935 CONFIG_CMD_MII * MII utility commands
936 CONFIG_CMD_MTDPARTS * MTD partition support
937 CONFIG_CMD_NAND * NAND support
938 CONFIG_CMD_NET bootp, tftpboot, rarpboot
939 CONFIG_CMD_NFS NFS support
940 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
941 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
942 CONFIG_CMD_PCI * pciinfo
943 CONFIG_CMD_PCMCIA * PCMCIA support
944 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
946 CONFIG_CMD_PORTIO * Port I/O
947 CONFIG_CMD_READ * Read raw data from partition
948 CONFIG_CMD_REGINFO * Register dump
949 CONFIG_CMD_RUN run command in env variable
950 CONFIG_CMD_SANDBOX * sb command to access sandbox features
951 CONFIG_CMD_SAVES * save S record dump
952 CONFIG_SCSI * SCSI Support
953 CONFIG_CMD_SDRAM * print SDRAM configuration information
954 (requires CONFIG_CMD_I2C)
955 CONFIG_CMD_SETGETDCR Support for DCR Register access
957 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
958 CONFIG_CMD_SHA1SUM * print sha1 memory digest
959 (requires CONFIG_CMD_MEMORY)
960 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
961 CONFIG_CMD_SOURCE "source" command Support
962 CONFIG_CMD_SPI * SPI serial bus support
963 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
964 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
965 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
966 CONFIG_CMD_TIMER * access to the system tick timer
967 CONFIG_CMD_USB * USB support
968 CONFIG_CMD_CDP * Cisco Discover Protocol support
969 CONFIG_CMD_MFSL * Microblaze FSL support
970 CONFIG_CMD_XIMG Load part of Multi Image
971 CONFIG_CMD_UUID * Generate random UUID or GUID string
973 EXAMPLE: If you want all functions except of network
974 support you can write:
976 #include "config_cmd_all.h"
977 #undef CONFIG_CMD_NET
980 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
982 Note: Don't enable the "icache" and "dcache" commands
983 (configuration option CONFIG_CMD_CACHE) unless you know
984 what you (and your U-Boot users) are doing. Data
985 cache cannot be enabled on systems like the 8xx or
986 8260 (where accesses to the IMMR region must be
987 uncached), and it cannot be disabled on all other
988 systems where we (mis-) use the data cache to hold an
989 initial stack and some data.
992 XXX - this list needs to get updated!
994 - Removal of commands
995 If no commands are needed to boot, you can disable
996 CONFIG_CMDLINE to remove them. In this case, the command line
997 will not be available, and when U-Boot wants to execute the
998 boot command (on start-up) it will call board_run_command()
999 instead. This can reduce image size significantly for very
1000 simple boot procedures.
1002 - Regular expression support:
1004 If this variable is defined, U-Boot is linked against
1005 the SLRE (Super Light Regular Expression) library,
1006 which adds regex support to some commands, as for
1007 example "env grep" and "setexpr".
1011 If this variable is defined, U-Boot will use a device tree
1012 to configure its devices, instead of relying on statically
1013 compiled #defines in the board file. This option is
1014 experimental and only available on a few boards. The device
1015 tree is available in the global data as gd->fdt_blob.
1017 U-Boot needs to get its device tree from somewhere. This can
1018 be done using one of the two options below:
1021 If this variable is defined, U-Boot will embed a device tree
1022 binary in its image. This device tree file should be in the
1023 board directory and called <soc>-<board>.dts. The binary file
1024 is then picked up in board_init_f() and made available through
1025 the global data structure as gd->blob.
1028 If this variable is defined, U-Boot will build a device tree
1029 binary. It will be called u-boot.dtb. Architecture-specific
1030 code will locate it at run-time. Generally this works by:
1032 cat u-boot.bin u-boot.dtb >image.bin
1034 and in fact, U-Boot does this for you, creating a file called
1035 u-boot-dtb.bin which is useful in the common case. You can
1036 still use the individual files if you need something more
1041 If this variable is defined, it enables watchdog
1042 support for the SoC. There must be support in the SoC
1043 specific code for a watchdog. For the 8xx and 8260
1044 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1045 register. When supported for a specific SoC is
1046 available, then no further board specific code should
1047 be needed to use it.
1050 When using a watchdog circuitry external to the used
1051 SoC, then define this variable and provide board
1052 specific code for the "hw_watchdog_reset" function.
1054 CONFIG_AT91_HW_WDT_TIMEOUT
1055 specify the timeout in seconds. default 2 seconds.
1058 CONFIG_VERSION_VARIABLE
1059 If this variable is defined, an environment variable
1060 named "ver" is created by U-Boot showing the U-Boot
1061 version as printed by the "version" command.
1062 Any change to this variable will be reverted at the
1067 When CONFIG_CMD_DATE is selected, the type of the RTC
1068 has to be selected, too. Define exactly one of the
1071 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1072 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1073 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1074 CONFIG_RTC_MC146818 - use MC146818 RTC
1075 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1076 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1077 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1078 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1079 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1080 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1081 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1082 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1083 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1086 Note that if the RTC uses I2C, then the I2C interface
1087 must also be configured. See I2C Support, below.
1090 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1092 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1093 chip-ngpio pairs that tell the PCA953X driver the number of
1094 pins supported by a particular chip.
1096 Note that if the GPIO device uses I2C, then the I2C interface
1097 must also be configured. See I2C Support, below.
1100 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1101 accesses and can checksum them or write a list of them out
1102 to memory. See the 'iotrace' command for details. This is
1103 useful for testing device drivers since it can confirm that
1104 the driver behaves the same way before and after a code
1105 change. Currently this is supported on sandbox and arm. To
1106 add support for your architecture, add '#include <iotrace.h>'
1107 to the bottom of arch/<arch>/include/asm/io.h and test.
1109 Example output from the 'iotrace stats' command is below.
1110 Note that if the trace buffer is exhausted, the checksum will
1111 still continue to operate.
1114 Start: 10000000 (buffer start address)
1115 Size: 00010000 (buffer size)
1116 Offset: 00000120 (current buffer offset)
1117 Output: 10000120 (start + offset)
1118 Count: 00000018 (number of trace records)
1119 CRC32: 9526fb66 (CRC32 of all trace records)
1121 - Timestamp Support:
1123 When CONFIG_TIMESTAMP is selected, the timestamp
1124 (date and time) of an image is printed by image
1125 commands like bootm or iminfo. This option is
1126 automatically enabled when you select CONFIG_CMD_DATE .
1128 - Partition Labels (disklabels) Supported:
1129 Zero or more of the following:
1130 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1131 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1132 Intel architecture, USB sticks, etc.
1133 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1134 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1135 bootloader. Note 2TB partition limit; see
1137 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1139 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1140 CONFIG_SCSI) you must configure support for at
1141 least one non-MTD partition type as well.
1144 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1145 board configurations files but used nowhere!
1147 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1148 be performed by calling the function
1149 ide_set_reset(int reset)
1150 which has to be defined in a board specific file
1155 Set this to enable ATAPI support.
1160 Set this to enable support for disks larger than 137GB
1161 Also look at CONFIG_SYS_64BIT_LBA.
1162 Whithout these , LBA48 support uses 32bit variables and will 'only'
1163 support disks up to 2.1TB.
1165 CONFIG_SYS_64BIT_LBA:
1166 When enabled, makes the IDE subsystem use 64bit sector addresses.
1170 At the moment only there is only support for the
1171 SYM53C8XX SCSI controller; define
1172 CONFIG_SCSI_SYM53C8XX to enable it.
1174 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1175 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1176 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1177 maximum numbers of LUNs, SCSI ID's and target
1179 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1181 The environment variable 'scsidevs' is set to the number of
1182 SCSI devices found during the last scan.
1184 - NETWORK Support (PCI):
1186 Support for Intel 8254x/8257x gigabit chips.
1189 Utility code for direct access to the SPI bus on Intel 8257x.
1190 This does not do anything useful unless you set at least one
1191 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1193 CONFIG_E1000_SPI_GENERIC
1194 Allow generic access to the SPI bus on the Intel 8257x, for
1195 example with the "sspi" command.
1198 Management command for E1000 devices. When used on devices
1199 with SPI support you can reprogram the EEPROM from U-Boot.
1202 Support for Intel 82557/82559/82559ER chips.
1203 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1204 write routine for first time initialisation.
1207 Support for Digital 2114x chips.
1208 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1209 modem chip initialisation (KS8761/QS6611).
1212 Support for National dp83815 chips.
1215 Support for National dp8382[01] gigabit chips.
1217 - NETWORK Support (other):
1219 CONFIG_DRIVER_AT91EMAC
1220 Support for AT91RM9200 EMAC.
1223 Define this to use reduced MII inteface
1225 CONFIG_DRIVER_AT91EMAC_QUIET
1226 If this defined, the driver is quiet.
1227 The driver doen't show link status messages.
1229 CONFIG_CALXEDA_XGMAC
1230 Support for the Calxeda XGMAC device
1233 Support for SMSC's LAN91C96 chips.
1235 CONFIG_LAN91C96_USE_32_BIT
1236 Define this to enable 32 bit addressing
1239 Support for SMSC's LAN91C111 chip
1241 CONFIG_SMC91111_BASE
1242 Define this to hold the physical address
1243 of the device (I/O space)
1245 CONFIG_SMC_USE_32_BIT
1246 Define this if data bus is 32 bits
1248 CONFIG_SMC_USE_IOFUNCS
1249 Define this to use i/o functions instead of macros
1250 (some hardware wont work with macros)
1252 CONFIG_DRIVER_TI_EMAC
1253 Support for davinci emac
1255 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1256 Define this if you have more then 3 PHYs.
1259 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1261 CONFIG_FTGMAC100_EGIGA
1262 Define this to use GE link update with gigabit PHY.
1263 Define this if FTGMAC100 is connected to gigabit PHY.
1264 If your system has 10/100 PHY only, it might not occur
1265 wrong behavior. Because PHY usually return timeout or
1266 useless data when polling gigabit status and gigabit
1267 control registers. This behavior won't affect the
1268 correctnessof 10/100 link speed update.
1271 Support for SMSC's LAN911x and LAN921x chips
1274 Define this to hold the physical address
1275 of the device (I/O space)
1277 CONFIG_SMC911X_32_BIT
1278 Define this if data bus is 32 bits
1280 CONFIG_SMC911X_16_BIT
1281 Define this if data bus is 16 bits. If your processor
1282 automatically converts one 32 bit word to two 16 bit
1283 words you may also try CONFIG_SMC911X_32_BIT.
1286 Support for Renesas on-chip Ethernet controller
1288 CONFIG_SH_ETHER_USE_PORT
1289 Define the number of ports to be used
1291 CONFIG_SH_ETHER_PHY_ADDR
1292 Define the ETH PHY's address
1294 CONFIG_SH_ETHER_CACHE_WRITEBACK
1295 If this option is set, the driver enables cache flush.
1299 Support for PWM module on the imx6.
1303 Support TPM devices.
1305 CONFIG_TPM_TIS_INFINEON
1306 Support for Infineon i2c bus TPM devices. Only one device
1307 per system is supported at this time.
1309 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1310 Define the burst count bytes upper limit
1313 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1315 CONFIG_TPM_ST33ZP24_I2C
1316 Support for STMicroelectronics ST33ZP24 I2C devices.
1317 Requires TPM_ST33ZP24 and I2C.
1319 CONFIG_TPM_ST33ZP24_SPI
1320 Support for STMicroelectronics ST33ZP24 SPI devices.
1321 Requires TPM_ST33ZP24 and SPI.
1323 CONFIG_TPM_ATMEL_TWI
1324 Support for Atmel TWI TPM device. Requires I2C support.
1327 Support for generic parallel port TPM devices. Only one device
1328 per system is supported at this time.
1330 CONFIG_TPM_TIS_BASE_ADDRESS
1331 Base address where the generic TPM device is mapped
1332 to. Contemporary x86 systems usually map it at
1336 Add tpm monitor functions.
1337 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1338 provides monitor access to authorized functions.
1341 Define this to enable the TPM support library which provides
1342 functional interfaces to some TPM commands.
1343 Requires support for a TPM device.
1345 CONFIG_TPM_AUTH_SESSIONS
1346 Define this to enable authorized functions in the TPM library.
1347 Requires CONFIG_TPM and CONFIG_SHA1.
1350 At the moment only the UHCI host controller is
1351 supported (PIP405, MIP405, MPC5200); define
1352 CONFIG_USB_UHCI to enable it.
1353 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1354 and define CONFIG_USB_STORAGE to enable the USB
1357 Supported are USB Keyboards and USB Floppy drives
1359 MPC5200 USB requires additional defines:
1361 for 528 MHz Clock: 0x0001bbbb
1365 for differential drivers: 0x00001000
1366 for single ended drivers: 0x00005000
1367 for differential drivers on PSC3: 0x00000100
1368 for single ended drivers on PSC3: 0x00004100
1369 CONFIG_SYS_USB_EVENT_POLL
1370 May be defined to allow interrupt polling
1371 instead of using asynchronous interrupts
1373 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1374 txfilltuning field in the EHCI controller on reset.
1376 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1377 HW module registers.
1380 Define the below if you wish to use the USB console.
1381 Once firmware is rebuilt from a serial console issue the
1382 command "setenv stdin usbtty; setenv stdout usbtty" and
1383 attach your USB cable. The Unix command "dmesg" should print
1384 it has found a new device. The environment variable usbtty
1385 can be set to gserial or cdc_acm to enable your device to
1386 appear to a USB host as a Linux gserial device or a
1387 Common Device Class Abstract Control Model serial device.
1388 If you select usbtty = gserial you should be able to enumerate
1390 # modprobe usbserial vendor=0xVendorID product=0xProductID
1391 else if using cdc_acm, simply setting the environment
1392 variable usbtty to be cdc_acm should suffice. The following
1393 might be defined in YourBoardName.h
1396 Define this to build a UDC device
1399 Define this to have a tty type of device available to
1400 talk to the UDC device
1403 Define this to enable the high speed support for usb
1404 device and usbtty. If this feature is enabled, a routine
1405 int is_usbd_high_speed(void)
1406 also needs to be defined by the driver to dynamically poll
1407 whether the enumeration has succeded at high speed or full
1410 CONFIG_SYS_CONSOLE_IS_IN_ENV
1411 Define this if you want stdin, stdout &/or stderr to
1415 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1416 Derive USB clock from external clock "blah"
1417 - CONFIG_SYS_USB_EXTC_CLK 0x02
1419 If you have a USB-IF assigned VendorID then you may wish to
1420 define your own vendor specific values either in BoardName.h
1421 or directly in usbd_vendor_info.h. If you don't define
1422 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1423 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1424 should pretend to be a Linux device to it's target host.
1426 CONFIG_USBD_MANUFACTURER
1427 Define this string as the name of your company for
1428 - CONFIG_USBD_MANUFACTURER "my company"
1430 CONFIG_USBD_PRODUCT_NAME
1431 Define this string as the name of your product
1432 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1434 CONFIG_USBD_VENDORID
1435 Define this as your assigned Vendor ID from the USB
1436 Implementors Forum. This *must* be a genuine Vendor ID
1437 to avoid polluting the USB namespace.
1438 - CONFIG_USBD_VENDORID 0xFFFF
1440 CONFIG_USBD_PRODUCTID
1441 Define this as the unique Product ID
1443 - CONFIG_USBD_PRODUCTID 0xFFFF
1445 - ULPI Layer Support:
1446 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1447 the generic ULPI layer. The generic layer accesses the ULPI PHY
1448 via the platform viewport, so you need both the genric layer and
1449 the viewport enabled. Currently only Chipidea/ARC based
1450 viewport is supported.
1451 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1452 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1453 If your ULPI phy needs a different reference clock than the
1454 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1455 the appropriate value in Hz.
1458 The MMC controller on the Intel PXA is supported. To
1459 enable this define CONFIG_MMC. The MMC can be
1460 accessed from the boot prompt by mapping the device
1461 to physical memory similar to flash. Command line is
1462 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1463 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1466 Support for Renesas on-chip MMCIF controller
1468 CONFIG_SH_MMCIF_ADDR
1469 Define the base address of MMCIF registers
1472 Define the clock frequency for MMCIF
1475 Enable the generic MMC driver
1477 CONFIG_SUPPORT_EMMC_BOOT
1478 Enable some additional features of the eMMC boot partitions.
1480 CONFIG_SUPPORT_EMMC_RPMB
1481 Enable the commands for reading, writing and programming the
1482 key for the Replay Protection Memory Block partition in eMMC.
1484 - USB Device Firmware Update (DFU) class support:
1485 CONFIG_USB_FUNCTION_DFU
1486 This enables the USB portion of the DFU USB class
1489 This enables the command "dfu" which is used to have
1490 U-Boot create a DFU class device via USB. This command
1491 requires that the "dfu_alt_info" environment variable be
1492 set and define the alt settings to expose to the host.
1495 This enables support for exposing (e)MMC devices via DFU.
1498 This enables support for exposing NAND devices via DFU.
1501 This enables support for exposing RAM via DFU.
1502 Note: DFU spec refer to non-volatile memory usage, but
1503 allow usages beyond the scope of spec - here RAM usage,
1504 one that would help mostly the developer.
1506 CONFIG_SYS_DFU_DATA_BUF_SIZE
1507 Dfu transfer uses a buffer before writing data to the
1508 raw storage device. Make the size (in bytes) of this buffer
1509 configurable. The size of this buffer is also configurable
1510 through the "dfu_bufsiz" environment variable.
1512 CONFIG_SYS_DFU_MAX_FILE_SIZE
1513 When updating files rather than the raw storage device,
1514 we use a static buffer to copy the file into and then write
1515 the buffer once we've been given the whole file. Define
1516 this to the maximum filesize (in bytes) for the buffer.
1517 Default is 4 MiB if undefined.
1519 DFU_DEFAULT_POLL_TIMEOUT
1520 Poll timeout [ms], is the timeout a device can send to the
1521 host. The host must wait for this timeout before sending
1522 a subsequent DFU_GET_STATUS request to the device.
1524 DFU_MANIFEST_POLL_TIMEOUT
1525 Poll timeout [ms], which the device sends to the host when
1526 entering dfuMANIFEST state. Host waits this timeout, before
1527 sending again an USB request to the device.
1529 - USB Device Android Fastboot support:
1530 CONFIG_USB_FUNCTION_FASTBOOT
1531 This enables the USB part of the fastboot gadget
1534 This enables the command "fastboot" which enables the Android
1535 fastboot mode for the platform's USB device. Fastboot is a USB
1536 protocol for downloading images, flashing and device control
1537 used on Android devices.
1538 See doc/README.android-fastboot for more information.
1540 CONFIG_ANDROID_BOOT_IMAGE
1541 This enables support for booting images which use the Android
1542 image format header.
1544 CONFIG_FASTBOOT_BUF_ADDR
1545 The fastboot protocol requires a large memory buffer for
1546 downloads. Define this to the starting RAM address to use for
1549 CONFIG_FASTBOOT_BUF_SIZE
1550 The fastboot protocol requires a large memory buffer for
1551 downloads. This buffer should be as large as possible for a
1552 platform. Define this to the size available RAM for fastboot.
1554 CONFIG_FASTBOOT_FLASH
1555 The fastboot protocol includes a "flash" command for writing
1556 the downloaded image to a non-volatile storage device. Define
1557 this to enable the "fastboot flash" command.
1559 CONFIG_FASTBOOT_FLASH_MMC_DEV
1560 The fastboot "flash" command requires additional information
1561 regarding the non-volatile storage device. Define this to
1562 the eMMC device that fastboot should use to store the image.
1564 CONFIG_FASTBOOT_GPT_NAME
1565 The fastboot "flash" command supports writing the downloaded
1566 image to the Protective MBR and the Primary GUID Partition
1567 Table. (Additionally, this downloaded image is post-processed
1568 to generate and write the Backup GUID Partition Table.)
1569 This occurs when the specified "partition name" on the
1570 "fastboot flash" command line matches this value.
1571 The default is "gpt" if undefined.
1573 CONFIG_FASTBOOT_MBR_NAME
1574 The fastboot "flash" command supports writing the downloaded
1576 This occurs when the "partition name" specified on the
1577 "fastboot flash" command line matches this value.
1578 If not defined the default value "mbr" is used.
1580 - Journaling Flash filesystem support:
1582 Define these for a default partition on a NAND device
1584 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1585 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1586 Define these for a default partition on a NOR device
1588 - FAT(File Allocation Table) filesystem write function support:
1591 Define this to enable support for saving memory data as a
1592 file in FAT formatted partition.
1594 This will also enable the command "fatwrite" enabling the
1595 user to write files to FAT.
1597 CBFS (Coreboot Filesystem) support
1600 Define this to enable support for reading from a Coreboot
1601 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1604 - FAT(File Allocation Table) filesystem cluster size:
1605 CONFIG_FS_FAT_MAX_CLUSTSIZE
1607 Define the max cluster size for fat operations else
1608 a default value of 65536 will be defined.
1611 See Kconfig help for available keyboard drivers.
1615 Define this to enable a custom keyboard support.
1616 This simply calls drv_keyboard_init() which must be
1617 defined in your board-specific files. This option is deprecated
1618 and is only used by novena. For new boards, use driver model
1622 CONFIG_VIDEO_SMI_LYNXEM
1623 Enable Silicon Motion SMI 712/710/810 Video chip. The
1624 video output is selected via environment 'videoout'
1625 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1628 CONFIG_VIDEO_SED13806
1629 Enable Epson SED13806 driver. This driver supports 8bpp
1630 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1631 or CONFIG_VIDEO_SED13806_16BPP
1634 Enable the Freescale DIU video driver. Reference boards for
1635 SOCs that have a DIU should define this macro to enable DIU
1636 support, and should also define these other macros:
1642 CONFIG_VIDEO_SW_CURSOR
1643 CONFIG_VGA_AS_SINGLE_DEVICE
1645 CONFIG_VIDEO_BMP_LOGO
1647 The DIU driver will look for the 'video-mode' environment
1648 variable, and if defined, enable the DIU as a console during
1649 boot. See the documentation file doc/README.video for a
1650 description of this variable.
1652 - LCD Support: CONFIG_LCD
1654 Define this to enable LCD support (for output to LCD
1655 display); also select one of the supported displays
1656 by defining one of these:
1660 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1662 CONFIG_NEC_NL6448AC33:
1664 NEC NL6448AC33-18. Active, color, single scan.
1666 CONFIG_NEC_NL6448BC20
1668 NEC NL6448BC20-08. 6.5", 640x480.
1669 Active, color, single scan.
1671 CONFIG_NEC_NL6448BC33_54
1673 NEC NL6448BC33-54. 10.4", 640x480.
1674 Active, color, single scan.
1678 Sharp 320x240. Active, color, single scan.
1679 It isn't 16x9, and I am not sure what it is.
1681 CONFIG_SHARP_LQ64D341
1683 Sharp LQ64D341 display, 640x480.
1684 Active, color, single scan.
1688 HLD1045 display, 640x480.
1689 Active, color, single scan.
1693 Optrex CBL50840-2 NF-FW 99 22 M5
1695 Hitachi LMG6912RPFC-00T
1699 320x240. Black & white.
1701 Normally display is black on white background; define
1702 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1704 CONFIG_LCD_ALIGNMENT
1706 Normally the LCD is page-aligned (typically 4KB). If this is
1707 defined then the LCD will be aligned to this value instead.
1708 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1709 here, since it is cheaper to change data cache settings on
1710 a per-section basis.
1712 CONFIG_CONSOLE_SCROLL_LINES
1714 When the console need to be scrolled, this is the number of
1715 lines to scroll by. It defaults to 1. Increasing this makes
1716 the console jump but can help speed up operation when scrolling
1721 Sometimes, for example if the display is mounted in portrait
1722 mode or even if it's mounted landscape but rotated by 180degree,
1723 we need to rotate our content of the display relative to the
1724 framebuffer, so that user can read the messages which are
1726 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1727 initialized with a given rotation from "vl_rot" out of
1728 "vidinfo_t" which is provided by the board specific code.
1729 The value for vl_rot is coded as following (matching to
1730 fbcon=rotate:<n> linux-kernel commandline):
1731 0 = no rotation respectively 0 degree
1732 1 = 90 degree rotation
1733 2 = 180 degree rotation
1734 3 = 270 degree rotation
1736 If CONFIG_LCD_ROTATION is not defined, the console will be
1737 initialized with 0degree rotation.
1741 Support drawing of RLE8-compressed bitmaps on the LCD.
1745 Enables an 'i2c edid' command which can read EDID
1746 information over I2C from an attached LCD display.
1748 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1750 If this option is set, the environment is checked for
1751 a variable "splashimage". If found, the usual display
1752 of logo, copyright and system information on the LCD
1753 is suppressed and the BMP image at the address
1754 specified in "splashimage" is loaded instead. The
1755 console is redirected to the "nulldev", too. This
1756 allows for a "silent" boot where a splash screen is
1757 loaded very quickly after power-on.
1759 CONFIG_SPLASHIMAGE_GUARD
1761 If this option is set, then U-Boot will prevent the environment
1762 variable "splashimage" from being set to a problematic address
1763 (see doc/README.displaying-bmps).
1764 This option is useful for targets where, due to alignment
1765 restrictions, an improperly aligned BMP image will cause a data
1766 abort. If you think you will not have problems with unaligned
1767 accesses (for example because your toolchain prevents them)
1768 there is no need to set this option.
1770 CONFIG_SPLASH_SCREEN_ALIGN
1772 If this option is set the splash image can be freely positioned
1773 on the screen. Environment variable "splashpos" specifies the
1774 position as "x,y". If a positive number is given it is used as
1775 number of pixel from left/top. If a negative number is given it
1776 is used as number of pixel from right/bottom. You can also
1777 specify 'm' for centering the image.
1780 setenv splashpos m,m
1781 => image at center of screen
1783 setenv splashpos 30,20
1784 => image at x = 30 and y = 20
1786 setenv splashpos -10,m
1787 => vertically centered image
1788 at x = dspWidth - bmpWidth - 9
1790 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1792 If this option is set, additionally to standard BMP
1793 images, gzipped BMP images can be displayed via the
1794 splashscreen support or the bmp command.
1796 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1798 If this option is set, 8-bit RLE compressed BMP images
1799 can be displayed via the splashscreen support or the
1802 - Do compressing for memory range:
1805 If this option is set, it would use zlib deflate method
1806 to compress the specified memory at its best effort.
1808 - Compression support:
1811 Enabled by default to support gzip compressed images.
1815 If this option is set, support for bzip2 compressed
1816 images is included. If not, only uncompressed and gzip
1817 compressed images are supported.
1819 NOTE: the bzip2 algorithm requires a lot of RAM, so
1820 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1825 If this option is set, support for lzma compressed
1828 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1829 requires an amount of dynamic memory that is given by the
1832 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1834 Where lc and lp stand for, respectively, Literal context bits
1835 and Literal pos bits.
1837 This value is upper-bounded by 14MB in the worst case. Anyway,
1838 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1839 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1840 a very small buffer.
1842 Use the lzmainfo tool to determinate the lc and lp values and
1843 then calculate the amount of needed dynamic memory (ensuring
1844 the appropriate CONFIG_SYS_MALLOC_LEN value).
1848 If this option is set, support for LZO compressed images
1854 The address of PHY on MII bus.
1856 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1858 The clock frequency of the MII bus
1862 If this option is set, support for speed/duplex
1863 detection of gigabit PHY is included.
1865 CONFIG_PHY_RESET_DELAY
1867 Some PHY like Intel LXT971A need extra delay after
1868 reset before any MII register access is possible.
1869 For such PHY, set this option to the usec delay
1870 required. (minimum 300usec for LXT971A)
1872 CONFIG_PHY_CMD_DELAY (ppc4xx)
1874 Some PHY like Intel LXT971A need extra delay after
1875 command issued before MII status register can be read
1880 Define a default value for the IP address to use for
1881 the default Ethernet interface, in case this is not
1882 determined through e.g. bootp.
1883 (Environment variable "ipaddr")
1885 - Server IP address:
1888 Defines a default value for the IP address of a TFTP
1889 server to contact when using the "tftboot" command.
1890 (Environment variable "serverip")
1892 CONFIG_KEEP_SERVERADDR
1894 Keeps the server's MAC address, in the env 'serveraddr'
1895 for passing to bootargs (like Linux's netconsole option)
1897 - Gateway IP address:
1900 Defines a default value for the IP address of the
1901 default router where packets to other networks are
1903 (Environment variable "gatewayip")
1908 Defines a default value for the subnet mask (or
1909 routing prefix) which is used to determine if an IP
1910 address belongs to the local subnet or needs to be
1911 forwarded through a router.
1912 (Environment variable "netmask")
1914 - Multicast TFTP Mode:
1917 Defines whether you want to support multicast TFTP as per
1918 rfc-2090; for example to work with atftp. Lets lots of targets
1919 tftp down the same boot image concurrently. Note: the Ethernet
1920 driver in use must provide a function: mcast() to join/leave a
1923 - BOOTP Recovery Mode:
1924 CONFIG_BOOTP_RANDOM_DELAY
1926 If you have many targets in a network that try to
1927 boot using BOOTP, you may want to avoid that all
1928 systems send out BOOTP requests at precisely the same
1929 moment (which would happen for instance at recovery
1930 from a power failure, when all systems will try to
1931 boot, thus flooding the BOOTP server. Defining
1932 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1933 inserted before sending out BOOTP requests. The
1934 following delays are inserted then:
1936 1st BOOTP request: delay 0 ... 1 sec
1937 2nd BOOTP request: delay 0 ... 2 sec
1938 3rd BOOTP request: delay 0 ... 4 sec
1940 BOOTP requests: delay 0 ... 8 sec
1942 CONFIG_BOOTP_ID_CACHE_SIZE
1944 BOOTP packets are uniquely identified using a 32-bit ID. The
1945 server will copy the ID from client requests to responses and
1946 U-Boot will use this to determine if it is the destination of
1947 an incoming response. Some servers will check that addresses
1948 aren't in use before handing them out (usually using an ARP
1949 ping) and therefore take up to a few hundred milliseconds to
1950 respond. Network congestion may also influence the time it
1951 takes for a response to make it back to the client. If that
1952 time is too long, U-Boot will retransmit requests. In order
1953 to allow earlier responses to still be accepted after these
1954 retransmissions, U-Boot's BOOTP client keeps a small cache of
1955 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1956 cache. The default is to keep IDs for up to four outstanding
1957 requests. Increasing this will allow U-Boot to accept offers
1958 from a BOOTP client in networks with unusually high latency.
1960 - DHCP Advanced Options:
1961 You can fine tune the DHCP functionality by defining
1962 CONFIG_BOOTP_* symbols:
1964 CONFIG_BOOTP_SUBNETMASK
1965 CONFIG_BOOTP_GATEWAY
1966 CONFIG_BOOTP_HOSTNAME
1967 CONFIG_BOOTP_NISDOMAIN
1968 CONFIG_BOOTP_BOOTPATH
1969 CONFIG_BOOTP_BOOTFILESIZE
1972 CONFIG_BOOTP_SEND_HOSTNAME
1973 CONFIG_BOOTP_NTPSERVER
1974 CONFIG_BOOTP_TIMEOFFSET
1975 CONFIG_BOOTP_VENDOREX
1976 CONFIG_BOOTP_MAY_FAIL
1978 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1979 environment variable, not the BOOTP server.
1981 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1982 after the configured retry count, the call will fail
1983 instead of starting over. This can be used to fail over
1984 to Link-local IP address configuration if the DHCP server
1987 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1988 serverip from a DHCP server, it is possible that more
1989 than one DNS serverip is offered to the client.
1990 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1991 serverip will be stored in the additional environment
1992 variable "dnsip2". The first DNS serverip is always
1993 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1996 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1997 to do a dynamic update of a DNS server. To do this, they
1998 need the hostname of the DHCP requester.
1999 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2000 of the "hostname" environment variable is passed as
2001 option 12 to the DHCP server.
2003 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2005 A 32bit value in microseconds for a delay between
2006 receiving a "DHCP Offer" and sending the "DHCP Request".
2007 This fixes a problem with certain DHCP servers that don't
2008 respond 100% of the time to a "DHCP request". E.g. On an
2009 AT91RM9200 processor running at 180MHz, this delay needed
2010 to be *at least* 15,000 usec before a Windows Server 2003
2011 DHCP server would reply 100% of the time. I recommend at
2012 least 50,000 usec to be safe. The alternative is to hope
2013 that one of the retries will be successful but note that
2014 the DHCP timeout and retry process takes a longer than
2017 - Link-local IP address negotiation:
2018 Negotiate with other link-local clients on the local network
2019 for an address that doesn't require explicit configuration.
2020 This is especially useful if a DHCP server cannot be guaranteed
2021 to exist in all environments that the device must operate.
2023 See doc/README.link-local for more information.
2026 CONFIG_CDP_DEVICE_ID
2028 The device id used in CDP trigger frames.
2030 CONFIG_CDP_DEVICE_ID_PREFIX
2032 A two character string which is prefixed to the MAC address
2037 A printf format string which contains the ascii name of
2038 the port. Normally is set to "eth%d" which sets
2039 eth0 for the first Ethernet, eth1 for the second etc.
2041 CONFIG_CDP_CAPABILITIES
2043 A 32bit integer which indicates the device capabilities;
2044 0x00000010 for a normal host which does not forwards.
2048 An ascii string containing the version of the software.
2052 An ascii string containing the name of the platform.
2056 A 32bit integer sent on the trigger.
2058 CONFIG_CDP_POWER_CONSUMPTION
2060 A 16bit integer containing the power consumption of the
2061 device in .1 of milliwatts.
2063 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2065 A byte containing the id of the VLAN.
2067 - Status LED: CONFIG_STATUS_LED
2069 Several configurations allow to display the current
2070 status using a LED. For instance, the LED will blink
2071 fast while running U-Boot code, stop blinking as
2072 soon as a reply to a BOOTP request was received, and
2073 start blinking slow once the Linux kernel is running
2074 (supported by a status LED driver in the Linux
2075 kernel). Defining CONFIG_STATUS_LED enables this
2081 The status LED can be connected to a GPIO pin.
2082 In such cases, the gpio_led driver can be used as a
2083 status LED backend implementation. Define CONFIG_GPIO_LED
2084 to include the gpio_led driver in the U-Boot binary.
2086 CONFIG_GPIO_LED_INVERTED_TABLE
2087 Some GPIO connected LEDs may have inverted polarity in which
2088 case the GPIO high value corresponds to LED off state and
2089 GPIO low value corresponds to LED on state.
2090 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2091 with a list of GPIO LEDs that have inverted polarity.
2093 - CAN Support: CONFIG_CAN_DRIVER
2095 Defining CONFIG_CAN_DRIVER enables CAN driver support
2096 on those systems that support this (optional)
2097 feature, like the TQM8xxL modules.
2099 - I2C Support: CONFIG_SYS_I2C
2101 This enable the NEW i2c subsystem, and will allow you to use
2102 i2c commands at the u-boot command line (as long as you set
2103 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2104 based realtime clock chips or other i2c devices. See
2105 common/cmd_i2c.c for a description of the command line
2108 ported i2c driver to the new framework:
2109 - drivers/i2c/soft_i2c.c:
2110 - activate first bus with CONFIG_SYS_I2C_SOFT define
2111 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2112 for defining speed and slave address
2113 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2114 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2115 for defining speed and slave address
2116 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2117 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2118 for defining speed and slave address
2119 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2120 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2121 for defining speed and slave address
2123 - drivers/i2c/fsl_i2c.c:
2124 - activate i2c driver with CONFIG_SYS_I2C_FSL
2125 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2126 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2127 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2129 - If your board supports a second fsl i2c bus, define
2130 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2131 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2132 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2135 - drivers/i2c/tegra_i2c.c:
2136 - activate this driver with CONFIG_SYS_I2C_TEGRA
2137 - This driver adds 4 i2c buses with a fix speed from
2138 100000 and the slave addr 0!
2140 - drivers/i2c/ppc4xx_i2c.c
2141 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2142 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2143 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2145 - drivers/i2c/i2c_mxc.c
2146 - activate this driver with CONFIG_SYS_I2C_MXC
2147 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2148 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2149 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2150 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2151 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2152 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2153 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2154 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2155 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2156 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2157 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2158 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2159 If those defines are not set, default value is 100000
2160 for speed, and 0 for slave.
2162 - drivers/i2c/rcar_i2c.c:
2163 - activate this driver with CONFIG_SYS_I2C_RCAR
2164 - This driver adds 4 i2c buses
2166 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2167 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2168 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2169 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2170 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2171 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2172 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2173 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2174 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2176 - drivers/i2c/sh_i2c.c:
2177 - activate this driver with CONFIG_SYS_I2C_SH
2178 - This driver adds from 2 to 5 i2c buses
2180 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2181 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2182 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2183 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2184 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2185 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2186 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2187 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2188 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2189 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2190 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2192 - drivers/i2c/omap24xx_i2c.c
2193 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2194 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2195 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2196 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2197 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2198 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2199 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2200 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2201 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2202 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2203 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2205 - drivers/i2c/zynq_i2c.c
2206 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2207 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2208 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2210 - drivers/i2c/s3c24x0_i2c.c:
2211 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2212 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2213 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2214 with a fix speed from 100000 and the slave addr 0!
2216 - drivers/i2c/ihs_i2c.c
2217 - activate this driver with CONFIG_SYS_I2C_IHS
2218 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2219 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2220 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2221 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2222 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2223 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2224 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2225 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2226 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2227 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2228 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2229 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2230 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2231 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2232 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2233 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2234 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2235 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2236 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2237 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2238 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2242 CONFIG_SYS_NUM_I2C_BUSES
2243 Hold the number of i2c buses you want to use.
2245 CONFIG_SYS_I2C_DIRECT_BUS
2246 define this, if you don't use i2c muxes on your hardware.
2247 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2250 CONFIG_SYS_I2C_MAX_HOPS
2251 define how many muxes are maximal consecutively connected
2252 on one i2c bus. If you not use i2c muxes, omit this
2255 CONFIG_SYS_I2C_BUSES
2256 hold a list of buses you want to use, only used if
2257 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2258 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2259 CONFIG_SYS_NUM_I2C_BUSES = 9:
2261 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2262 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2263 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2264 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2265 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2266 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2267 {1, {I2C_NULL_HOP}}, \
2268 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2269 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2273 bus 0 on adapter 0 without a mux
2274 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2275 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2276 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2277 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2278 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2279 bus 6 on adapter 1 without a mux
2280 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2281 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2283 If you do not have i2c muxes on your board, omit this define.
2285 - Legacy I2C Support: CONFIG_HARD_I2C
2287 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2288 provides the following compelling advantages:
2290 - more than one i2c adapter is usable
2291 - approved multibus support
2292 - better i2c mux support
2294 ** Please consider updating your I2C driver now. **
2296 These enable legacy I2C serial bus commands. Defining
2297 CONFIG_HARD_I2C will include the appropriate I2C driver
2298 for the selected CPU.
2300 This will allow you to use i2c commands at the u-boot
2301 command line (as long as you set CONFIG_CMD_I2C in
2302 CONFIG_COMMANDS) and communicate with i2c based realtime
2303 clock chips. See common/cmd_i2c.c for a description of the
2304 command line interface.
2306 CONFIG_HARD_I2C selects a hardware I2C controller.
2308 There are several other quantities that must also be
2309 defined when you define CONFIG_HARD_I2C.
2311 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2312 to be the frequency (in Hz) at which you wish your i2c bus
2313 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2314 the CPU's i2c node address).
2316 Now, the u-boot i2c code for the mpc8xx
2317 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2318 and so its address should therefore be cleared to 0 (See,
2319 eg, MPC823e User's Manual p.16-473). So, set
2320 CONFIG_SYS_I2C_SLAVE to 0.
2322 CONFIG_SYS_I2C_INIT_MPC5XXX
2324 When a board is reset during an i2c bus transfer
2325 chips might think that the current transfer is still
2326 in progress. Reset the slave devices by sending start
2327 commands until the slave device responds.
2329 That's all that's required for CONFIG_HARD_I2C.
2331 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2332 then the following macros need to be defined (examples are
2333 from include/configs/lwmon.h):
2337 (Optional). Any commands necessary to enable the I2C
2338 controller or configure ports.
2340 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2344 (Only for MPC8260 CPU). The I/O port to use (the code
2345 assumes both bits are on the same port). Valid values
2346 are 0..3 for ports A..D.
2350 The code necessary to make the I2C data line active
2351 (driven). If the data line is open collector, this
2354 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2358 The code necessary to make the I2C data line tri-stated
2359 (inactive). If the data line is open collector, this
2362 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2366 Code that returns true if the I2C data line is high,
2369 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2373 If <bit> is true, sets the I2C data line high. If it
2374 is false, it clears it (low).
2376 eg: #define I2C_SDA(bit) \
2377 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2378 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2382 If <bit> is true, sets the I2C clock line high. If it
2383 is false, it clears it (low).
2385 eg: #define I2C_SCL(bit) \
2386 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2387 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2391 This delay is invoked four times per clock cycle so this
2392 controls the rate of data transfer. The data rate thus
2393 is 1 / (I2C_DELAY * 4). Often defined to be something
2396 #define I2C_DELAY udelay(2)
2398 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2400 If your arch supports the generic GPIO framework (asm/gpio.h),
2401 then you may alternatively define the two GPIOs that are to be
2402 used as SCL / SDA. Any of the previous I2C_xxx macros will
2403 have GPIO-based defaults assigned to them as appropriate.
2405 You should define these to the GPIO value as given directly to
2406 the generic GPIO functions.
2408 CONFIG_SYS_I2C_INIT_BOARD
2410 When a board is reset during an i2c bus transfer
2411 chips might think that the current transfer is still
2412 in progress. On some boards it is possible to access
2413 the i2c SCLK line directly, either by using the
2414 processor pin as a GPIO or by having a second pin
2415 connected to the bus. If this option is defined a
2416 custom i2c_init_board() routine in boards/xxx/board.c
2417 is run early in the boot sequence.
2419 CONFIG_SYS_I2C_BOARD_LATE_INIT
2421 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2422 defined a custom i2c_board_late_init() routine in
2423 boards/xxx/board.c is run AFTER the operations in i2c_init()
2424 is completed. This callpoint can be used to unreset i2c bus
2425 using CPU i2c controller register accesses for CPUs whose i2c
2426 controller provide such a method. It is called at the end of
2427 i2c_init() to allow i2c_init operations to setup the i2c bus
2428 controller on the CPU (e.g. setting bus speed & slave address).
2430 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2432 This option enables configuration of bi_iic_fast[] flags
2433 in u-boot bd_info structure based on u-boot environment
2434 variable "i2cfast". (see also i2cfast)
2436 CONFIG_I2C_MULTI_BUS
2438 This option allows the use of multiple I2C buses, each of which
2439 must have a controller. At any point in time, only one bus is
2440 active. To switch to a different bus, use the 'i2c dev' command.
2441 Note that bus numbering is zero-based.
2443 CONFIG_SYS_I2C_NOPROBES
2445 This option specifies a list of I2C devices that will be skipped
2446 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2447 is set, specify a list of bus-device pairs. Otherwise, specify
2448 a 1D array of device addresses
2451 #undef CONFIG_I2C_MULTI_BUS
2452 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2454 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2456 #define CONFIG_I2C_MULTI_BUS
2457 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2459 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2461 CONFIG_SYS_SPD_BUS_NUM
2463 If defined, then this indicates the I2C bus number for DDR SPD.
2464 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2466 CONFIG_SYS_RTC_BUS_NUM
2468 If defined, then this indicates the I2C bus number for the RTC.
2469 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2471 CONFIG_SYS_DTT_BUS_NUM
2473 If defined, then this indicates the I2C bus number for the DTT.
2474 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2476 CONFIG_SYS_I2C_DTT_ADDR:
2478 If defined, specifies the I2C address of the DTT device.
2479 If not defined, then U-Boot uses predefined value for
2480 specified DTT device.
2482 CONFIG_SOFT_I2C_READ_REPEATED_START
2484 defining this will force the i2c_read() function in
2485 the soft_i2c driver to perform an I2C repeated start
2486 between writing the address pointer and reading the
2487 data. If this define is omitted the default behaviour
2488 of doing a stop-start sequence will be used. Most I2C
2489 devices can use either method, but some require one or
2492 - SPI Support: CONFIG_SPI
2494 Enables SPI driver (so far only tested with
2495 SPI EEPROM, also an instance works with Crystal A/D and
2496 D/As on the SACSng board)
2500 Enables the driver for SPI controller on SuperH. Currently
2501 only SH7757 is supported.
2505 Enables a software (bit-bang) SPI driver rather than
2506 using hardware support. This is a general purpose
2507 driver that only requires three general I/O port pins
2508 (two outputs, one input) to function. If this is
2509 defined, the board configuration must define several
2510 SPI configuration items (port pins to use, etc). For
2511 an example, see include/configs/sacsng.h.
2515 Enables a hardware SPI driver for general-purpose reads
2516 and writes. As with CONFIG_SOFT_SPI, the board configuration
2517 must define a list of chip-select function pointers.
2518 Currently supported on some MPC8xxx processors. For an
2519 example, see include/configs/mpc8349emds.h.
2523 Enables the driver for the SPI controllers on i.MX and MXC
2524 SoCs. Currently i.MX31/35/51 are supported.
2526 CONFIG_SYS_SPI_MXC_WAIT
2527 Timeout for waiting until spi transfer completed.
2528 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2530 - FPGA Support: CONFIG_FPGA
2532 Enables FPGA subsystem.
2534 CONFIG_FPGA_<vendor>
2536 Enables support for specific chip vendors.
2539 CONFIG_FPGA_<family>
2541 Enables support for FPGA family.
2542 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2546 Specify the number of FPGA devices to support.
2548 CONFIG_CMD_FPGA_LOADMK
2550 Enable support for fpga loadmk command
2552 CONFIG_CMD_FPGA_LOADP
2554 Enable support for fpga loadp command - load partial bitstream
2556 CONFIG_CMD_FPGA_LOADBP
2558 Enable support for fpga loadbp command - load partial bitstream
2561 CONFIG_SYS_FPGA_PROG_FEEDBACK
2563 Enable printing of hash marks during FPGA configuration.
2565 CONFIG_SYS_FPGA_CHECK_BUSY
2567 Enable checks on FPGA configuration interface busy
2568 status by the configuration function. This option
2569 will require a board or device specific function to
2574 If defined, a function that provides delays in the FPGA
2575 configuration driver.
2577 CONFIG_SYS_FPGA_CHECK_CTRLC
2578 Allow Control-C to interrupt FPGA configuration
2580 CONFIG_SYS_FPGA_CHECK_ERROR
2582 Check for configuration errors during FPGA bitfile
2583 loading. For example, abort during Virtex II
2584 configuration if the INIT_B line goes low (which
2585 indicated a CRC error).
2587 CONFIG_SYS_FPGA_WAIT_INIT
2589 Maximum time to wait for the INIT_B line to de-assert
2590 after PROB_B has been de-asserted during a Virtex II
2591 FPGA configuration sequence. The default time is 500
2594 CONFIG_SYS_FPGA_WAIT_BUSY
2596 Maximum time to wait for BUSY to de-assert during
2597 Virtex II FPGA configuration. The default is 5 ms.
2599 CONFIG_SYS_FPGA_WAIT_CONFIG
2601 Time to wait after FPGA configuration. The default is
2604 - Configuration Management:
2607 Some SoCs need special image types (e.g. U-Boot binary
2608 with a special header) as build targets. By defining
2609 CONFIG_BUILD_TARGET in the SoC / board header, this
2610 special image will be automatically built upon calling
2615 If defined, this string will be added to the U-Boot
2616 version information (U_BOOT_VERSION)
2618 - Vendor Parameter Protection:
2620 U-Boot considers the values of the environment
2621 variables "serial#" (Board Serial Number) and
2622 "ethaddr" (Ethernet Address) to be parameters that
2623 are set once by the board vendor / manufacturer, and
2624 protects these variables from casual modification by
2625 the user. Once set, these variables are read-only,
2626 and write or delete attempts are rejected. You can
2627 change this behaviour:
2629 If CONFIG_ENV_OVERWRITE is #defined in your config
2630 file, the write protection for vendor parameters is
2631 completely disabled. Anybody can change or delete
2634 Alternatively, if you define _both_ an ethaddr in the
2635 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2636 Ethernet address is installed in the environment,
2637 which can be changed exactly ONCE by the user. [The
2638 serial# is unaffected by this, i. e. it remains
2641 The same can be accomplished in a more flexible way
2642 for any variable by configuring the type of access
2643 to allow for those variables in the ".flags" variable
2644 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2649 Define this variable to enable the reservation of
2650 "protected RAM", i. e. RAM which is not overwritten
2651 by U-Boot. Define CONFIG_PRAM to hold the number of
2652 kB you want to reserve for pRAM. You can overwrite
2653 this default value by defining an environment
2654 variable "pram" to the number of kB you want to
2655 reserve. Note that the board info structure will
2656 still show the full amount of RAM. If pRAM is
2657 reserved, a new environment variable "mem" will
2658 automatically be defined to hold the amount of
2659 remaining RAM in a form that can be passed as boot
2660 argument to Linux, for instance like that:
2662 setenv bootargs ... mem=\${mem}
2665 This way you can tell Linux not to use this memory,
2666 either, which results in a memory region that will
2667 not be affected by reboots.
2669 *WARNING* If your board configuration uses automatic
2670 detection of the RAM size, you must make sure that
2671 this memory test is non-destructive. So far, the
2672 following board configurations are known to be
2675 IVMS8, IVML24, SPD8xx, TQM8xxL,
2676 HERMES, IP860, RPXlite, LWMON,
2679 - Access to physical memory region (> 4GB)
2680 Some basic support is provided for operations on memory not
2681 normally accessible to U-Boot - e.g. some architectures
2682 support access to more than 4GB of memory on 32-bit
2683 machines using physical address extension or similar.
2684 Define CONFIG_PHYSMEM to access this basic support, which
2685 currently only supports clearing the memory.
2690 Define this variable to stop the system in case of a
2691 fatal error, so that you have to reset it manually.
2692 This is probably NOT a good idea for an embedded
2693 system where you want the system to reboot
2694 automatically as fast as possible, but it may be
2695 useful during development since you can try to debug
2696 the conditions that lead to the situation.
2698 CONFIG_NET_RETRY_COUNT
2700 This variable defines the number of retries for
2701 network operations like ARP, RARP, TFTP, or BOOTP
2702 before giving up the operation. If not defined, a
2703 default value of 5 is used.
2707 Timeout waiting for an ARP reply in milliseconds.
2711 Timeout in milliseconds used in NFS protocol.
2712 If you encounter "ERROR: Cannot umount" in nfs command,
2713 try longer timeout such as
2714 #define CONFIG_NFS_TIMEOUT 10000UL
2716 - Command Interpreter:
2717 CONFIG_AUTO_COMPLETE
2719 Enable auto completion of commands using TAB.
2721 CONFIG_SYS_PROMPT_HUSH_PS2
2723 This defines the secondary prompt string, which is
2724 printed when the command interpreter needs more input
2725 to complete a command. Usually "> ".
2729 In the current implementation, the local variables
2730 space and global environment variables space are
2731 separated. Local variables are those you define by
2732 simply typing `name=value'. To access a local
2733 variable later on, you have write `$name' or
2734 `${name}'; to execute the contents of a variable
2735 directly type `$name' at the command prompt.
2737 Global environment variables are those you use
2738 setenv/printenv to work with. To run a command stored
2739 in such a variable, you need to use the run command,
2740 and you must not use the '$' sign to access them.
2742 To store commands and special characters in a
2743 variable, please use double quotation marks
2744 surrounding the whole text of the variable, instead
2745 of the backslashes before semicolons and special
2748 - Command Line Editing and History:
2749 CONFIG_CMDLINE_EDITING
2751 Enable editing and History functions for interactive
2752 command line input operations
2754 - Command Line PS1/PS2 support:
2755 CONFIG_CMDLINE_PS_SUPPORT
2757 Enable support for changing the command prompt string
2758 at run-time. Only static string is supported so far.
2759 The string is obtained from environment variables PS1
2762 - Default Environment:
2763 CONFIG_EXTRA_ENV_SETTINGS
2765 Define this to contain any number of null terminated
2766 strings (variable = value pairs) that will be part of
2767 the default environment compiled into the boot image.
2769 For example, place something like this in your
2770 board's config file:
2772 #define CONFIG_EXTRA_ENV_SETTINGS \
2776 Warning: This method is based on knowledge about the
2777 internal format how the environment is stored by the
2778 U-Boot code. This is NOT an official, exported
2779 interface! Although it is unlikely that this format
2780 will change soon, there is no guarantee either.
2781 You better know what you are doing here.
2783 Note: overly (ab)use of the default environment is
2784 discouraged. Make sure to check other ways to preset
2785 the environment like the "source" command or the
2788 CONFIG_ENV_VARS_UBOOT_CONFIG
2790 Define this in order to add variables describing the
2791 U-Boot build configuration to the default environment.
2792 These will be named arch, cpu, board, vendor, and soc.
2794 Enabling this option will cause the following to be defined:
2802 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2804 Define this in order to add variables describing certain
2805 run-time determined information about the hardware to the
2806 environment. These will be named board_name, board_rev.
2808 CONFIG_DELAY_ENVIRONMENT
2810 Normally the environment is loaded when the board is
2811 initialised so that it is available to U-Boot. This inhibits
2812 that so that the environment is not available until
2813 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2814 this is instead controlled by the value of
2815 /config/load-environment.
2817 - Parallel Flash support:
2820 Traditionally U-Boot was run on systems with parallel NOR
2821 flash. This option is used to disable support for parallel NOR
2822 flash. This option should be defined if the board does not have
2825 If this option is not defined one of the generic flash drivers
2826 (e.g. CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
2827 selected or the board must provide an implementation of the
2828 flash API (see include/flash.h).
2830 - DataFlash Support:
2831 CONFIG_HAS_DATAFLASH
2833 Defining this option enables DataFlash features and
2834 allows to read/write in Dataflash via the standard
2837 - Serial Flash support
2840 Defining this option enables SPI flash commands
2841 'sf probe/read/write/erase/update'.
2843 Usage requires an initial 'probe' to define the serial
2844 flash parameters, followed by read/write/erase/update
2847 The following defaults may be provided by the platform
2848 to handle the common case when only a single serial
2849 flash is present on the system.
2851 CONFIG_SF_DEFAULT_BUS Bus identifier
2852 CONFIG_SF_DEFAULT_CS Chip-select
2853 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2854 CONFIG_SF_DEFAULT_SPEED in Hz
2858 Define this option to include a destructive SPI flash
2861 CONFIG_SF_DUAL_FLASH Dual flash memories
2863 Define this option to use dual flash support where two flash
2864 memories can be connected with a given cs line.
2865 Currently Xilinx Zynq qspi supports these type of connections.
2867 - SystemACE Support:
2870 Adding this option adds support for Xilinx SystemACE
2871 chips attached via some sort of local bus. The address
2872 of the chip must also be defined in the
2873 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2875 #define CONFIG_SYSTEMACE
2876 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2878 When SystemACE support is added, the "ace" device type
2879 becomes available to the fat commands, i.e. fatls.
2881 - TFTP Fixed UDP Port:
2884 If this is defined, the environment variable tftpsrcp
2885 is used to supply the TFTP UDP source port value.
2886 If tftpsrcp isn't defined, the normal pseudo-random port
2887 number generator is used.
2889 Also, the environment variable tftpdstp is used to supply
2890 the TFTP UDP destination port value. If tftpdstp isn't
2891 defined, the normal port 69 is used.
2893 The purpose for tftpsrcp is to allow a TFTP server to
2894 blindly start the TFTP transfer using the pre-configured
2895 target IP address and UDP port. This has the effect of
2896 "punching through" the (Windows XP) firewall, allowing
2897 the remainder of the TFTP transfer to proceed normally.
2898 A better solution is to properly configure the firewall,
2899 but sometimes that is not allowed.
2904 This enables a generic 'hash' command which can produce
2905 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2909 Enable the hash verify command (hash -v). This adds to code
2912 CONFIG_SHA1 - This option enables support of hashing using SHA1
2913 algorithm. The hash is calculated in software.
2914 CONFIG_SHA256 - This option enables support of hashing using
2915 SHA256 algorithm. The hash is calculated in software.
2916 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2917 for SHA1/SHA256 hashing.
2918 This affects the 'hash' command and also the
2919 hash_lookup_algo() function.
2920 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2921 hardware-acceleration for SHA1/SHA256 progressive hashing.
2922 Data can be streamed in a block at a time and the hashing
2923 is performed in hardware.
2925 Note: There is also a sha1sum command, which should perhaps
2926 be deprecated in favour of 'hash sha1'.
2928 - Freescale i.MX specific commands:
2929 CONFIG_CMD_HDMIDETECT
2930 This enables 'hdmidet' command which returns true if an
2931 HDMI monitor is detected. This command is i.MX 6 specific.
2934 This enables the 'bmode' (bootmode) command for forcing
2935 a boot from specific media.
2937 This is useful for forcing the ROM's usb downloader to
2938 activate upon a watchdog reset which is nice when iterating
2939 on U-Boot. Using the reset button or running bmode normal
2940 will set it back to normal. This command currently
2941 supports i.MX53 and i.MX6.
2943 - bootcount support:
2944 CONFIG_BOOTCOUNT_LIMIT
2946 This enables the bootcounter support, see:
2947 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2950 enable special bootcounter support on at91sam9xe based boards.
2952 enable special bootcounter support on blackfin based boards.
2954 enable special bootcounter support on da850 based boards.
2955 CONFIG_BOOTCOUNT_RAM
2956 enable support for the bootcounter in RAM
2957 CONFIG_BOOTCOUNT_I2C
2958 enable support for the bootcounter on an i2c (like RTC) device.
2959 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2960 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2962 CONFIG_BOOTCOUNT_ALEN = address len
2964 - Show boot progress:
2965 CONFIG_SHOW_BOOT_PROGRESS
2967 Defining this option allows to add some board-
2968 specific code (calling a user-provided function
2969 "show_boot_progress(int)") that enables you to show
2970 the system's boot progress on some display (for
2971 example, some LED's) on your board. At the moment,
2972 the following checkpoints are implemented:
2975 Legacy uImage format:
2978 1 common/cmd_bootm.c before attempting to boot an image
2979 -1 common/cmd_bootm.c Image header has bad magic number
2980 2 common/cmd_bootm.c Image header has correct magic number
2981 -2 common/cmd_bootm.c Image header has bad checksum
2982 3 common/cmd_bootm.c Image header has correct checksum
2983 -3 common/cmd_bootm.c Image data has bad checksum
2984 4 common/cmd_bootm.c Image data has correct checksum
2985 -4 common/cmd_bootm.c Image is for unsupported architecture
2986 5 common/cmd_bootm.c Architecture check OK
2987 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2988 6 common/cmd_bootm.c Image Type check OK
2989 -6 common/cmd_bootm.c gunzip uncompression error
2990 -7 common/cmd_bootm.c Unimplemented compression type
2991 7 common/cmd_bootm.c Uncompression OK
2992 8 common/cmd_bootm.c No uncompress/copy overwrite error
2993 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2995 9 common/image.c Start initial ramdisk verification
2996 -10 common/image.c Ramdisk header has bad magic number
2997 -11 common/image.c Ramdisk header has bad checksum
2998 10 common/image.c Ramdisk header is OK
2999 -12 common/image.c Ramdisk data has bad checksum
3000 11 common/image.c Ramdisk data has correct checksum
3001 12 common/image.c Ramdisk verification complete, start loading
3002 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3003 13 common/image.c Start multifile image verification
3004 14 common/image.c No initial ramdisk, no multifile, continue.
3006 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3008 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3009 -31 post/post.c POST test failed, detected by post_output_backlog()
3010 -32 post/post.c POST test failed, detected by post_run_single()
3012 34 common/cmd_doc.c before loading a Image from a DOC device
3013 -35 common/cmd_doc.c Bad usage of "doc" command
3014 35 common/cmd_doc.c correct usage of "doc" command
3015 -36 common/cmd_doc.c No boot device
3016 36 common/cmd_doc.c correct boot device
3017 -37 common/cmd_doc.c Unknown Chip ID on boot device
3018 37 common/cmd_doc.c correct chip ID found, device available
3019 -38 common/cmd_doc.c Read Error on boot device
3020 38 common/cmd_doc.c reading Image header from DOC device OK
3021 -39 common/cmd_doc.c Image header has bad magic number
3022 39 common/cmd_doc.c Image header has correct magic number
3023 -40 common/cmd_doc.c Error reading Image from DOC device
3024 40 common/cmd_doc.c Image header has correct magic number
3025 41 common/cmd_ide.c before loading a Image from a IDE device
3026 -42 common/cmd_ide.c Bad usage of "ide" command
3027 42 common/cmd_ide.c correct usage of "ide" command
3028 -43 common/cmd_ide.c No boot device
3029 43 common/cmd_ide.c boot device found
3030 -44 common/cmd_ide.c Device not available
3031 44 common/cmd_ide.c Device available
3032 -45 common/cmd_ide.c wrong partition selected
3033 45 common/cmd_ide.c partition selected
3034 -46 common/cmd_ide.c Unknown partition table
3035 46 common/cmd_ide.c valid partition table found
3036 -47 common/cmd_ide.c Invalid partition type
3037 47 common/cmd_ide.c correct partition type
3038 -48 common/cmd_ide.c Error reading Image Header on boot device
3039 48 common/cmd_ide.c reading Image Header from IDE device OK
3040 -49 common/cmd_ide.c Image header has bad magic number
3041 49 common/cmd_ide.c Image header has correct magic number
3042 -50 common/cmd_ide.c Image header has bad checksum
3043 50 common/cmd_ide.c Image header has correct checksum
3044 -51 common/cmd_ide.c Error reading Image from IDE device
3045 51 common/cmd_ide.c reading Image from IDE device OK
3046 52 common/cmd_nand.c before loading a Image from a NAND device
3047 -53 common/cmd_nand.c Bad usage of "nand" command
3048 53 common/cmd_nand.c correct usage of "nand" command
3049 -54 common/cmd_nand.c No boot device
3050 54 common/cmd_nand.c boot device found
3051 -55 common/cmd_nand.c Unknown Chip ID on boot device
3052 55 common/cmd_nand.c correct chip ID found, device available
3053 -56 common/cmd_nand.c Error reading Image Header on boot device
3054 56 common/cmd_nand.c reading Image Header from NAND device OK
3055 -57 common/cmd_nand.c Image header has bad magic number
3056 57 common/cmd_nand.c Image header has correct magic number
3057 -58 common/cmd_nand.c Error reading Image from NAND device
3058 58 common/cmd_nand.c reading Image from NAND device OK
3060 -60 common/env_common.c Environment has a bad CRC, using default
3062 64 net/eth.c starting with Ethernet configuration.
3063 -64 net/eth.c no Ethernet found.
3064 65 net/eth.c Ethernet found.
3066 -80 common/cmd_net.c usage wrong
3067 80 common/cmd_net.c before calling net_loop()
3068 -81 common/cmd_net.c some error in net_loop() occurred
3069 81 common/cmd_net.c net_loop() back without error
3070 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3071 82 common/cmd_net.c trying automatic boot
3072 83 common/cmd_net.c running "source" command
3073 -83 common/cmd_net.c some error in automatic boot or "source" command
3074 84 common/cmd_net.c end without errors
3079 100 common/cmd_bootm.c Kernel FIT Image has correct format
3080 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3081 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3082 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3083 102 common/cmd_bootm.c Kernel unit name specified
3084 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3085 103 common/cmd_bootm.c Found configuration node
3086 104 common/cmd_bootm.c Got kernel subimage node offset
3087 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3088 105 common/cmd_bootm.c Kernel subimage hash verification OK
3089 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3090 106 common/cmd_bootm.c Architecture check OK
3091 -106 common/cmd_bootm.c Kernel subimage has wrong type
3092 107 common/cmd_bootm.c Kernel subimage type OK
3093 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3094 108 common/cmd_bootm.c Got kernel subimage data/size
3095 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3096 -109 common/cmd_bootm.c Can't get kernel subimage type
3097 -110 common/cmd_bootm.c Can't get kernel subimage comp
3098 -111 common/cmd_bootm.c Can't get kernel subimage os
3099 -112 common/cmd_bootm.c Can't get kernel subimage load address
3100 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3102 120 common/image.c Start initial ramdisk verification
3103 -120 common/image.c Ramdisk FIT image has incorrect format
3104 121 common/image.c Ramdisk FIT image has correct format
3105 122 common/image.c No ramdisk subimage unit name, using configuration
3106 -122 common/image.c Can't get configuration for ramdisk subimage
3107 123 common/image.c Ramdisk unit name specified
3108 -124 common/image.c Can't get ramdisk subimage node offset
3109 125 common/image.c Got ramdisk subimage node offset
3110 -125 common/image.c Ramdisk subimage hash verification failed
3111 126 common/image.c Ramdisk subimage hash verification OK
3112 -126 common/image.c Ramdisk subimage for unsupported architecture
3113 127 common/image.c Architecture check OK
3114 -127 common/image.c Can't get ramdisk subimage data/size
3115 128 common/image.c Got ramdisk subimage data/size
3116 129 common/image.c Can't get ramdisk load address
3117 -129 common/image.c Got ramdisk load address
3119 -130 common/cmd_doc.c Incorrect FIT image format
3120 131 common/cmd_doc.c FIT image format OK
3122 -140 common/cmd_ide.c Incorrect FIT image format
3123 141 common/cmd_ide.c FIT image format OK
3125 -150 common/cmd_nand.c Incorrect FIT image format
3126 151 common/cmd_nand.c FIT image format OK
3128 - legacy image format:
3129 CONFIG_IMAGE_FORMAT_LEGACY
3130 enables the legacy image format support in U-Boot.
3133 enabled if CONFIG_FIT_SIGNATURE is not defined.
3135 CONFIG_DISABLE_IMAGE_LEGACY
3136 disable the legacy image format
3138 This define is introduced, as the legacy image format is
3139 enabled per default for backward compatibility.
3141 - FIT image support:
3142 CONFIG_FIT_DISABLE_SHA256
3143 Supporting SHA256 hashes has quite an impact on binary size.
3144 For constrained systems sha256 hash support can be disabled
3147 TODO(sjg@chromium.org): Adjust this option to be positive,
3148 and move it to Kconfig
3150 - Standalone program support:
3151 CONFIG_STANDALONE_LOAD_ADDR
3153 This option defines a board specific value for the
3154 address where standalone program gets loaded, thus
3155 overwriting the architecture dependent default
3158 - Frame Buffer Address:
3161 Define CONFIG_FB_ADDR if you want to use specific
3162 address for frame buffer. This is typically the case
3163 when using a graphics controller has separate video
3164 memory. U-Boot will then place the frame buffer at
3165 the given address instead of dynamically reserving it
3166 in system RAM by calling lcd_setmem(), which grabs
3167 the memory for the frame buffer depending on the
3168 configured panel size.
3170 Please see board_init_f function.
3172 - Automatic software updates via TFTP server
3174 CONFIG_UPDATE_TFTP_CNT_MAX
3175 CONFIG_UPDATE_TFTP_MSEC_MAX
3177 These options enable and control the auto-update feature;
3178 for a more detailed description refer to doc/README.update.
3180 - MTD Support (mtdparts command, UBI support)
3183 Adds the MTD device infrastructure from the Linux kernel.
3184 Needed for mtdparts command support.
3186 CONFIG_MTD_PARTITIONS
3188 Adds the MTD partitioning infrastructure from the Linux
3189 kernel. Needed for UBI support.
3194 Adds commands for interacting with MTD partitions formatted
3195 with the UBI flash translation layer
3197 Requires also defining CONFIG_RBTREE
3199 CONFIG_UBI_SILENCE_MSG
3201 Make the verbose messages from UBI stop printing. This leaves
3202 warnings and errors enabled.
3205 CONFIG_MTD_UBI_WL_THRESHOLD
3206 This parameter defines the maximum difference between the highest
3207 erase counter value and the lowest erase counter value of eraseblocks
3208 of UBI devices. When this threshold is exceeded, UBI starts performing
3209 wear leveling by means of moving data from eraseblock with low erase
3210 counter to eraseblocks with high erase counter.
3212 The default value should be OK for SLC NAND flashes, NOR flashes and
3213 other flashes which have eraseblock life-cycle 100000 or more.
3214 However, in case of MLC NAND flashes which typically have eraseblock
3215 life-cycle less than 10000, the threshold should be lessened (e.g.,
3216 to 128 or 256, although it does not have to be power of 2).
3220 CONFIG_MTD_UBI_BEB_LIMIT
3221 This option specifies the maximum bad physical eraseblocks UBI
3222 expects on the MTD device (per 1024 eraseblocks). If the
3223 underlying flash does not admit of bad eraseblocks (e.g. NOR
3224 flash), this value is ignored.
3226 NAND datasheets often specify the minimum and maximum NVM
3227 (Number of Valid Blocks) for the flashes' endurance lifetime.
3228 The maximum expected bad eraseblocks per 1024 eraseblocks
3229 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3230 which gives 20 for most NANDs (MaxNVB is basically the total
3231 count of eraseblocks on the chip).
3233 To put it differently, if this value is 20, UBI will try to
3234 reserve about 1.9% of physical eraseblocks for bad blocks
3235 handling. And that will be 1.9% of eraseblocks on the entire
3236 NAND chip, not just the MTD partition UBI attaches. This means
3237 that if you have, say, a NAND flash chip admits maximum 40 bad
3238 eraseblocks, and it is split on two MTD partitions of the same
3239 size, UBI will reserve 40 eraseblocks when attaching a
3244 CONFIG_MTD_UBI_FASTMAP
3245 Fastmap is a mechanism which allows attaching an UBI device
3246 in nearly constant time. Instead of scanning the whole MTD device it
3247 only has to locate a checkpoint (called fastmap) on the device.
3248 The on-flash fastmap contains all information needed to attach
3249 the device. Using fastmap makes only sense on large devices where
3250 attaching by scanning takes long. UBI will not automatically install
3251 a fastmap on old images, but you can set the UBI parameter
3252 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3253 that fastmap-enabled images are still usable with UBI implementations
3254 without fastmap support. On typical flash devices the whole fastmap
3255 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3257 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3258 Set this parameter to enable fastmap automatically on images
3262 CONFIG_MTD_UBI_FM_DEBUG
3263 Enable UBI fastmap debug
3269 Adds commands for interacting with UBI volumes formatted as
3270 UBIFS. UBIFS is read-only in u-boot.
3272 Requires UBI support as well as CONFIG_LZO
3274 CONFIG_UBIFS_SILENCE_MSG
3276 Make the verbose messages from UBIFS stop printing. This leaves
3277 warnings and errors enabled.
3281 Enable building of SPL globally.
3284 LDSCRIPT for linking the SPL binary.
3286 CONFIG_SPL_MAX_FOOTPRINT
3287 Maximum size in memory allocated to the SPL, BSS included.
3288 When defined, the linker checks that the actual memory
3289 used by SPL from _start to __bss_end does not exceed it.
3290 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3291 must not be both defined at the same time.
3294 Maximum size of the SPL image (text, data, rodata, and
3295 linker lists sections), BSS excluded.
3296 When defined, the linker checks that the actual size does
3299 CONFIG_SPL_TEXT_BASE
3300 TEXT_BASE for linking the SPL binary.
3302 CONFIG_SPL_RELOC_TEXT_BASE
3303 Address to relocate to. If unspecified, this is equal to
3304 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3306 CONFIG_SPL_BSS_START_ADDR
3307 Link address for the BSS within the SPL binary.
3309 CONFIG_SPL_BSS_MAX_SIZE
3310 Maximum size in memory allocated to the SPL BSS.
3311 When defined, the linker checks that the actual memory used
3312 by SPL from __bss_start to __bss_end does not exceed it.
3313 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3314 must not be both defined at the same time.
3317 Adress of the start of the stack SPL will use
3319 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3320 When defined, SPL will panic() if the image it has
3321 loaded does not have a signature.
3322 Defining this is useful when code which loads images
3323 in SPL cannot guarantee that absolutely all read errors
3325 An example is the LPC32XX MLC NAND driver, which will
3326 consider that a completely unreadable NAND block is bad,
3327 and thus should be skipped silently.
3329 CONFIG_SPL_ABORT_ON_RAW_IMAGE
3330 When defined, SPL will proceed to another boot method
3331 if the image it has loaded does not have a signature.
3333 CONFIG_SPL_RELOC_STACK
3334 Adress of the start of the stack SPL will use after
3335 relocation. If unspecified, this is equal to
3338 CONFIG_SYS_SPL_MALLOC_START
3339 Starting address of the malloc pool used in SPL.
3340 When this option is set the full malloc is used in SPL and
3341 it is set up by spl_init() and before that, the simple malloc()
3342 can be used if CONFIG_SYS_MALLOC_F is defined.
3344 CONFIG_SYS_SPL_MALLOC_SIZE
3345 The size of the malloc pool used in SPL.
3347 CONFIG_SPL_FRAMEWORK
3348 Enable the SPL framework under common/. This framework
3349 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3350 NAND loading of the Linux Kernel.
3353 Enable booting directly to an OS from SPL.
3354 See also: doc/README.falcon
3356 CONFIG_SPL_DISPLAY_PRINT
3357 For ARM, enable an optional function to print more information
3358 about the running system.
3360 CONFIG_SPL_INIT_MINIMAL
3361 Arch init code should be built for a very small image
3363 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3364 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3365 Address and partition on the MMC to load U-Boot from
3366 when the MMC is being used in raw mode.
3368 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3369 Partition on the MMC to load U-Boot from when the MMC is being
3372 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3373 Sector to load kernel uImage from when MMC is being
3374 used in raw mode (for Falcon mode)
3376 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3377 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3378 Sector and number of sectors to load kernel argument
3379 parameters from when MMC is being used in raw mode
3382 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3383 Partition on the MMC to load U-Boot from when the MMC is being
3386 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3387 Filename to read to load U-Boot when reading from filesystem
3389 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3390 Filename to read to load kernel uImage when reading
3391 from filesystem (for Falcon mode)
3393 CONFIG_SPL_FS_LOAD_ARGS_NAME
3394 Filename to read to load kernel argument parameters
3395 when reading from filesystem (for Falcon mode)
3397 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3398 Set this for NAND SPL on PPC mpc83xx targets, so that
3399 start.S waits for the rest of the SPL to load before
3400 continuing (the hardware starts execution after just
3401 loading the first page rather than the full 4K).
3403 CONFIG_SPL_SKIP_RELOCATE
3404 Avoid SPL relocation
3406 CONFIG_SPL_NAND_BASE
3407 Include nand_base.c in the SPL. Requires
3408 CONFIG_SPL_NAND_DRIVERS.
3410 CONFIG_SPL_NAND_DRIVERS
3411 SPL uses normal NAND drivers, not minimal drivers.
3414 Include standard software ECC in the SPL
3416 CONFIG_SPL_NAND_SIMPLE
3417 Support for NAND boot using simple NAND drivers that
3418 expose the cmd_ctrl() interface.
3421 Support for a lightweight UBI (fastmap) scanner and
3424 CONFIG_SPL_NAND_RAW_ONLY
3425 Support to boot only raw u-boot.bin images. Use this only
3426 if you need to save space.
3428 CONFIG_SPL_COMMON_INIT_DDR
3429 Set for common ddr init with serial presence detect in
3432 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3433 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3434 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3435 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3436 CONFIG_SYS_NAND_ECCBYTES
3437 Defines the size and behavior of the NAND that SPL uses
3440 CONFIG_SPL_NAND_BOOT
3441 Add support NAND boot
3443 CONFIG_SYS_NAND_U_BOOT_OFFS
3444 Location in NAND to read U-Boot from
3446 CONFIG_SYS_NAND_U_BOOT_DST
3447 Location in memory to load U-Boot to
3449 CONFIG_SYS_NAND_U_BOOT_SIZE
3450 Size of image to load
3452 CONFIG_SYS_NAND_U_BOOT_START
3453 Entry point in loaded image to jump to
3455 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3456 Define this if you need to first read the OOB and then the
3457 data. This is used, for example, on davinci platforms.
3459 CONFIG_SPL_OMAP3_ID_NAND
3460 Support for an OMAP3-specific set of functions to return the
3461 ID and MFR of the first attached NAND chip, if present.
3463 CONFIG_SPL_RAM_DEVICE
3464 Support for running image already present in ram, in SPL binary
3467 Image offset to which the SPL should be padded before appending
3468 the SPL payload. By default, this is defined as
3469 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3470 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3471 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3474 Final target image containing SPL and payload. Some SPLs
3475 use an arch-specific makefile fragment instead, for
3476 example if more than one image needs to be produced.
3478 CONFIG_FIT_SPL_PRINT
3479 Printing information about a FIT image adds quite a bit of
3480 code to SPL. So this is normally disabled in SPL. Use this
3481 option to re-enable it. This will affect the output of the
3482 bootm command when booting a FIT image.
3486 Enable building of TPL globally.
3489 Image offset to which the TPL should be padded before appending
3490 the TPL payload. By default, this is defined as
3491 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3492 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3493 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3495 - Interrupt support (PPC):
3497 There are common interrupt_init() and timer_interrupt()
3498 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3499 for CPU specific initialization. interrupt_init_cpu()
3500 should set decrementer_count to appropriate value. If
3501 CPU resets decrementer automatically after interrupt
3502 (ppc4xx) it should set decrementer_count to zero.
3503 timer_interrupt() calls timer_interrupt_cpu() for CPU
3504 specific handling. If board has watchdog / status_led
3505 / other_activity_monitor it works automatically from
3506 general timer_interrupt().
3509 Board initialization settings:
3510 ------------------------------
3512 During Initialization u-boot calls a number of board specific functions
3513 to allow the preparation of board specific prerequisites, e.g. pin setup
3514 before drivers are initialized. To enable these callbacks the
3515 following configuration macros have to be defined. Currently this is
3516 architecture specific, so please check arch/your_architecture/lib/board.c
3517 typically in board_init_f() and board_init_r().
3519 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3520 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3521 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3522 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3524 Configuration Settings:
3525 -----------------------
3527 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3528 Optionally it can be defined to support 64-bit memory commands.
3530 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3531 undefine this when you're short of memory.
3533 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3534 width of the commands listed in the 'help' command output.
3536 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3537 prompt for user input.
3539 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3541 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3543 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3545 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3546 the application (usually a Linux kernel) when it is
3549 - CONFIG_SYS_BAUDRATE_TABLE:
3550 List of legal baudrate settings for this board.
3552 - CONFIG_SYS_CONSOLE_INFO_QUIET
3553 Suppress display of console information at boot.
3555 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3556 Enable the call to overwrite_console().
3558 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3559 Enable overwrite of previous console environment settings.
3561 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3562 Begin and End addresses of the area used by the
3565 - CONFIG_SYS_ALT_MEMTEST:
3566 Enable an alternate, more extensive memory test.
3568 - CONFIG_SYS_MEMTEST_SCRATCH:
3569 Scratch address used by the alternate memory test
3570 You only need to set this if address zero isn't writeable
3572 - CONFIG_SYS_MEM_RESERVE_SECURE
3573 Only implemented for ARMv8 for now.
3574 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3575 is substracted from total RAM and won't be reported to OS.
3576 This memory can be used as secure memory. A variable
3577 gd->arch.secure_ram is used to track the location. In systems
3578 the RAM base is not zero, or RAM is divided into banks,
3579 this variable needs to be recalcuated to get the address.
3581 - CONFIG_SYS_MEM_TOP_HIDE:
3582 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3583 this specified memory area will get subtracted from the top
3584 (end) of RAM and won't get "touched" at all by U-Boot. By
3585 fixing up gd->ram_size the Linux kernel should gets passed
3586 the now "corrected" memory size and won't touch it either.
3587 This should work for arch/ppc and arch/powerpc. Only Linux
3588 board ports in arch/powerpc with bootwrapper support that
3589 recalculate the memory size from the SDRAM controller setup
3590 will have to get fixed in Linux additionally.
3592 This option can be used as a workaround for the 440EPx/GRx
3593 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3596 WARNING: Please make sure that this value is a multiple of
3597 the Linux page size (normally 4k). If this is not the case,
3598 then the end address of the Linux memory will be located at a
3599 non page size aligned address and this could cause major
3602 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3603 Enable temporary baudrate change while serial download
3605 - CONFIG_SYS_SDRAM_BASE:
3606 Physical start address of SDRAM. _Must_ be 0 here.
3608 - CONFIG_SYS_FLASH_BASE:
3609 Physical start address of Flash memory.
3611 - CONFIG_SYS_MONITOR_BASE:
3612 Physical start address of boot monitor code (set by
3613 make config files to be same as the text base address
3614 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3615 CONFIG_SYS_FLASH_BASE when booting from flash.
3617 - CONFIG_SYS_MONITOR_LEN:
3618 Size of memory reserved for monitor code, used to
3619 determine _at_compile_time_ (!) if the environment is
3620 embedded within the U-Boot image, or in a separate
3623 - CONFIG_SYS_MALLOC_LEN:
3624 Size of DRAM reserved for malloc() use.
3626 - CONFIG_SYS_MALLOC_F_LEN
3627 Size of the malloc() pool for use before relocation. If
3628 this is defined, then a very simple malloc() implementation
3629 will become available before relocation. The address is just
3630 below the global data, and the stack is moved down to make
3633 This feature allocates regions with increasing addresses
3634 within the region. calloc() is supported, but realloc()
3635 is not available. free() is supported but does nothing.
3636 The memory will be freed (or in fact just forgotten) when
3637 U-Boot relocates itself.
3639 - CONFIG_SYS_MALLOC_SIMPLE
3640 Provides a simple and small malloc() and calloc() for those
3641 boards which do not use the full malloc in SPL (which is
3642 enabled with CONFIG_SYS_SPL_MALLOC_START).
3644 - CONFIG_SYS_NONCACHED_MEMORY:
3645 Size of non-cached memory area. This area of memory will be
3646 typically located right below the malloc() area and mapped
3647 uncached in the MMU. This is useful for drivers that would
3648 otherwise require a lot of explicit cache maintenance. For
3649 some drivers it's also impossible to properly maintain the
3650 cache. For example if the regions that need to be flushed
3651 are not a multiple of the cache-line size, *and* padding
3652 cannot be allocated between the regions to align them (i.e.
3653 if the HW requires a contiguous array of regions, and the
3654 size of each region is not cache-aligned), then a flush of
3655 one region may result in overwriting data that hardware has
3656 written to another region in the same cache-line. This can
3657 happen for example in network drivers where descriptors for
3658 buffers are typically smaller than the CPU cache-line (e.g.
3659 16 bytes vs. 32 or 64 bytes).
3661 Non-cached memory is only supported on 32-bit ARM at present.
3663 - CONFIG_SYS_BOOTM_LEN:
3664 Normally compressed uImages are limited to an
3665 uncompressed size of 8 MBytes. If this is not enough,
3666 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3667 to adjust this setting to your needs.
3669 - CONFIG_SYS_BOOTMAPSZ:
3670 Maximum size of memory mapped by the startup code of
3671 the Linux kernel; all data that must be processed by
3672 the Linux kernel (bd_info, boot arguments, FDT blob if
3673 used) must be put below this limit, unless "bootm_low"
3674 environment variable is defined and non-zero. In such case
3675 all data for the Linux kernel must be between "bootm_low"
3676 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3677 variable "bootm_mapsize" will override the value of
3678 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3679 then the value in "bootm_size" will be used instead.
3681 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3682 Enable initrd_high functionality. If defined then the
3683 initrd_high feature is enabled and the bootm ramdisk subcommand
3686 - CONFIG_SYS_BOOT_GET_CMDLINE:
3687 Enables allocating and saving kernel cmdline in space between
3688 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3690 - CONFIG_SYS_BOOT_GET_KBD:
3691 Enables allocating and saving a kernel copy of the bd_info in
3692 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3694 - CONFIG_SYS_MAX_FLASH_BANKS:
3695 Max number of Flash memory banks
3697 - CONFIG_SYS_MAX_FLASH_SECT:
3698 Max number of sectors on a Flash chip
3700 - CONFIG_SYS_FLASH_ERASE_TOUT:
3701 Timeout for Flash erase operations (in ms)
3703 - CONFIG_SYS_FLASH_WRITE_TOUT:
3704 Timeout for Flash write operations (in ms)
3706 - CONFIG_SYS_FLASH_LOCK_TOUT
3707 Timeout for Flash set sector lock bit operation (in ms)
3709 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3710 Timeout for Flash clear lock bits operation (in ms)
3712 - CONFIG_SYS_FLASH_PROTECTION
3713 If defined, hardware flash sectors protection is used
3714 instead of U-Boot software protection.
3716 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3718 Enable TFTP transfers directly to flash memory;
3719 without this option such a download has to be
3720 performed in two steps: (1) download to RAM, and (2)
3721 copy from RAM to flash.
3723 The two-step approach is usually more reliable, since
3724 you can check if the download worked before you erase
3725 the flash, but in some situations (when system RAM is
3726 too limited to allow for a temporary copy of the
3727 downloaded image) this option may be very useful.
3729 - CONFIG_SYS_FLASH_CFI:
3730 Define if the flash driver uses extra elements in the
3731 common flash structure for storing flash geometry.
3733 - CONFIG_FLASH_CFI_DRIVER
3734 This option also enables the building of the cfi_flash driver
3735 in the drivers directory
3737 - CONFIG_FLASH_CFI_MTD
3738 This option enables the building of the cfi_mtd driver
3739 in the drivers directory. The driver exports CFI flash
3742 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3743 Use buffered writes to flash.
3745 - CONFIG_FLASH_SPANSION_S29WS_N
3746 s29ws-n MirrorBit flash has non-standard addresses for buffered
3749 - CONFIG_SYS_FLASH_QUIET_TEST
3750 If this option is defined, the common CFI flash doesn't
3751 print it's warning upon not recognized FLASH banks. This
3752 is useful, if some of the configured banks are only
3753 optionally available.
3755 - CONFIG_FLASH_SHOW_PROGRESS
3756 If defined (must be an integer), print out countdown
3757 digits and dots. Recommended value: 45 (9..1) for 80
3758 column displays, 15 (3..1) for 40 column displays.
3760 - CONFIG_FLASH_VERIFY
3761 If defined, the content of the flash (destination) is compared
3762 against the source after the write operation. An error message
3763 will be printed when the contents are not identical.
3764 Please note that this option is useless in nearly all cases,
3765 since such flash programming errors usually are detected earlier
3766 while unprotecting/erasing/programming. Please only enable
3767 this option if you really know what you are doing.
3769 - CONFIG_SYS_RX_ETH_BUFFER:
3770 Defines the number of Ethernet receive buffers. On some
3771 Ethernet controllers it is recommended to set this value
3772 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3773 buffers can be full shortly after enabling the interface
3774 on high Ethernet traffic.
3775 Defaults to 4 if not defined.
3777 - CONFIG_ENV_MAX_ENTRIES
3779 Maximum number of entries in the hash table that is used
3780 internally to store the environment settings. The default
3781 setting is supposed to be generous and should work in most
3782 cases. This setting can be used to tune behaviour; see
3783 lib/hashtable.c for details.
3785 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3786 - CONFIG_ENV_FLAGS_LIST_STATIC
3787 Enable validation of the values given to environment variables when
3788 calling env set. Variables can be restricted to only decimal,
3789 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3790 the variables can also be restricted to IP address or MAC address.
3792 The format of the list is:
3793 type_attribute = [s|d|x|b|i|m]
3794 access_attribute = [a|r|o|c]
3795 attributes = type_attribute[access_attribute]
3796 entry = variable_name[:attributes]
3799 The type attributes are:
3800 s - String (default)
3803 b - Boolean ([1yYtT|0nNfF])
3807 The access attributes are:
3813 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3814 Define this to a list (string) to define the ".flags"
3815 environment variable in the default or embedded environment.
3817 - CONFIG_ENV_FLAGS_LIST_STATIC
3818 Define this to a list (string) to define validation that
3819 should be done if an entry is not found in the ".flags"
3820 environment variable. To override a setting in the static
3821 list, simply add an entry for the same variable name to the
3824 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3825 regular expression. This allows multiple variables to define the same
3826 flags without explicitly listing them for each variable.
3828 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3829 If defined, don't allow the -f switch to env set override variable
3832 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3833 This is set by OMAP boards for the max time that reset should
3834 be asserted. See doc/README.omap-reset-time for details on how
3835 the value can be calculated on a given board.
3838 If stdint.h is available with your toolchain you can define this
3839 option to enable it. You can provide option 'USE_STDINT=1' when
3840 building U-Boot to enable this.
3842 The following definitions that deal with the placement and management
3843 of environment data (variable area); in general, we support the
3844 following configurations:
3846 - CONFIG_BUILD_ENVCRC:
3848 Builds up envcrc with the target environment so that external utils
3849 may easily extract it and embed it in final U-Boot images.
3851 - CONFIG_ENV_IS_IN_FLASH:
3853 Define this if the environment is in flash memory.
3855 a) The environment occupies one whole flash sector, which is
3856 "embedded" in the text segment with the U-Boot code. This
3857 happens usually with "bottom boot sector" or "top boot
3858 sector" type flash chips, which have several smaller
3859 sectors at the start or the end. For instance, such a
3860 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3861 such a case you would place the environment in one of the
3862 4 kB sectors - with U-Boot code before and after it. With
3863 "top boot sector" type flash chips, you would put the
3864 environment in one of the last sectors, leaving a gap
3865 between U-Boot and the environment.
3867 - CONFIG_ENV_OFFSET:
3869 Offset of environment data (variable area) to the
3870 beginning of flash memory; for instance, with bottom boot
3871 type flash chips the second sector can be used: the offset
3872 for this sector is given here.
3874 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3878 This is just another way to specify the start address of
3879 the flash sector containing the environment (instead of
3882 - CONFIG_ENV_SECT_SIZE:
3884 Size of the sector containing the environment.
3887 b) Sometimes flash chips have few, equal sized, BIG sectors.
3888 In such a case you don't want to spend a whole sector for
3893 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3894 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3895 of this flash sector for the environment. This saves
3896 memory for the RAM copy of the environment.
3898 It may also save flash memory if you decide to use this
3899 when your environment is "embedded" within U-Boot code,
3900 since then the remainder of the flash sector could be used
3901 for U-Boot code. It should be pointed out that this is
3902 STRONGLY DISCOURAGED from a robustness point of view:
3903 updating the environment in flash makes it always
3904 necessary to erase the WHOLE sector. If something goes
3905 wrong before the contents has been restored from a copy in
3906 RAM, your target system will be dead.
3908 - CONFIG_ENV_ADDR_REDUND
3909 CONFIG_ENV_SIZE_REDUND
3911 These settings describe a second storage area used to hold
3912 a redundant copy of the environment data, so that there is
3913 a valid backup copy in case there is a power failure during
3914 a "saveenv" operation.
3916 BE CAREFUL! Any changes to the flash layout, and some changes to the
3917 source code will make it necessary to adapt <board>/u-boot.lds*
3921 - CONFIG_ENV_IS_IN_NVRAM:
3923 Define this if you have some non-volatile memory device
3924 (NVRAM, battery buffered SRAM) which you want to use for the
3930 These two #defines are used to determine the memory area you
3931 want to use for environment. It is assumed that this memory
3932 can just be read and written to, without any special
3935 BE CAREFUL! The first access to the environment happens quite early
3936 in U-Boot initialization (when we try to get the setting of for the
3937 console baudrate). You *MUST* have mapped your NVRAM area then, or
3940 Please note that even with NVRAM we still use a copy of the
3941 environment in RAM: we could work on NVRAM directly, but we want to
3942 keep settings there always unmodified except somebody uses "saveenv"
3943 to save the current settings.
3946 - CONFIG_ENV_IS_IN_EEPROM:
3948 Use this if you have an EEPROM or similar serial access
3949 device and a driver for it.
3951 - CONFIG_ENV_OFFSET:
3954 These two #defines specify the offset and size of the
3955 environment area within the total memory of your EEPROM.
3957 - CONFIG_SYS_I2C_EEPROM_ADDR:
3958 If defined, specified the chip address of the EEPROM device.
3959 The default address is zero.
3961 - CONFIG_SYS_I2C_EEPROM_BUS:
3962 If defined, specified the i2c bus of the EEPROM device.
3964 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3965 If defined, the number of bits used to address bytes in a
3966 single page in the EEPROM device. A 64 byte page, for example
3967 would require six bits.
3969 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3970 If defined, the number of milliseconds to delay between
3971 page writes. The default is zero milliseconds.
3973 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3974 The length in bytes of the EEPROM memory array address. Note
3975 that this is NOT the chip address length!
3977 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3978 EEPROM chips that implement "address overflow" are ones
3979 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3980 address and the extra bits end up in the "chip address" bit
3981 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3984 Note that we consider the length of the address field to
3985 still be one byte because the extra address bits are hidden
3986 in the chip address.
3988 - CONFIG_SYS_EEPROM_SIZE:
3989 The size in bytes of the EEPROM device.
3991 - CONFIG_ENV_EEPROM_IS_ON_I2C
3992 define this, if you have I2C and SPI activated, and your
3993 EEPROM, which holds the environment, is on the I2C bus.
3995 - CONFIG_I2C_ENV_EEPROM_BUS
3996 if you have an Environment on an EEPROM reached over
3997 I2C muxes, you can define here, how to reach this
3998 EEPROM. For example:
4000 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4002 EEPROM which holds the environment, is reached over
4003 a pca9547 i2c mux with address 0x70, channel 3.
4005 - CONFIG_ENV_IS_IN_DATAFLASH:
4007 Define this if you have a DataFlash memory device which you
4008 want to use for the environment.
4010 - CONFIG_ENV_OFFSET:
4014 These three #defines specify the offset and size of the
4015 environment area within the total memory of your DataFlash placed
4016 at the specified address.
4018 - CONFIG_ENV_IS_IN_SPI_FLASH:
4020 Define this if you have a SPI Flash memory device which you
4021 want to use for the environment.
4023 - CONFIG_ENV_OFFSET:
4026 These two #defines specify the offset and size of the
4027 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4028 aligned to an erase sector boundary.
4030 - CONFIG_ENV_SECT_SIZE:
4032 Define the SPI flash's sector size.
4034 - CONFIG_ENV_OFFSET_REDUND (optional):
4036 This setting describes a second storage area of CONFIG_ENV_SIZE
4037 size used to hold a redundant copy of the environment data, so
4038 that there is a valid backup copy in case there is a power failure
4039 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
4040 aligned to an erase sector boundary.
4042 - CONFIG_ENV_SPI_BUS (optional):
4043 - CONFIG_ENV_SPI_CS (optional):
4045 Define the SPI bus and chip select. If not defined they will be 0.
4047 - CONFIG_ENV_SPI_MAX_HZ (optional):
4049 Define the SPI max work clock. If not defined then use 1MHz.
4051 - CONFIG_ENV_SPI_MODE (optional):
4053 Define the SPI work mode. If not defined then use SPI_MODE_3.
4055 - CONFIG_ENV_IS_IN_REMOTE:
4057 Define this if you have a remote memory space which you
4058 want to use for the local device's environment.
4063 These two #defines specify the address and size of the
4064 environment area within the remote memory space. The
4065 local device can get the environment from remote memory
4066 space by SRIO or PCIE links.
4068 BE CAREFUL! For some special cases, the local device can not use
4069 "saveenv" command. For example, the local device will get the
4070 environment stored in a remote NOR flash by SRIO or PCIE link,
4071 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4073 - CONFIG_ENV_IS_IN_NAND:
4075 Define this if you have a NAND device which you want to use
4076 for the environment.
4078 - CONFIG_ENV_OFFSET:
4081 These two #defines specify the offset and size of the environment
4082 area within the first NAND device. CONFIG_ENV_OFFSET must be
4083 aligned to an erase block boundary.
4085 - CONFIG_ENV_OFFSET_REDUND (optional):
4087 This setting describes a second storage area of CONFIG_ENV_SIZE
4088 size used to hold a redundant copy of the environment data, so
4089 that there is a valid backup copy in case there is a power failure
4090 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
4091 aligned to an erase block boundary.
4093 - CONFIG_ENV_RANGE (optional):
4095 Specifies the length of the region in which the environment
4096 can be written. This should be a multiple of the NAND device's
4097 block size. Specifying a range with more erase blocks than
4098 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4099 the range to be avoided.
4101 - CONFIG_ENV_OFFSET_OOB (optional):
4103 Enables support for dynamically retrieving the offset of the
4104 environment from block zero's out-of-band data. The
4105 "nand env.oob" command can be used to record this offset.
4106 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4107 using CONFIG_ENV_OFFSET_OOB.
4109 - CONFIG_NAND_ENV_DST
4111 Defines address in RAM to which the nand_spl code should copy the
4112 environment. If redundant environment is used, it will be copied to
4113 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4115 - CONFIG_ENV_IS_IN_UBI:
4117 Define this if you have an UBI volume that you want to use for the
4118 environment. This has the benefit of wear-leveling the environment
4119 accesses, which is important on NAND.
4121 - CONFIG_ENV_UBI_PART:
4123 Define this to a string that is the mtd partition containing the UBI.
4125 - CONFIG_ENV_UBI_VOLUME:
4127 Define this to the name of the volume that you want to store the
4130 - CONFIG_ENV_UBI_VOLUME_REDUND:
4132 Define this to the name of another volume to store a second copy of
4133 the environment in. This will enable redundant environments in UBI.
4134 It is assumed that both volumes are in the same MTD partition.
4136 - CONFIG_UBI_SILENCE_MSG
4137 - CONFIG_UBIFS_SILENCE_MSG
4139 You will probably want to define these to avoid a really noisy system
4140 when storing the env in UBI.
4142 - CONFIG_ENV_IS_IN_FAT:
4143 Define this if you want to use the FAT file system for the environment.
4145 - FAT_ENV_INTERFACE:
4147 Define this to a string that is the name of the block device.
4149 - FAT_ENV_DEV_AND_PART:
4151 Define this to a string to specify the partition of the device. It can
4154 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4155 - "D:P": device D partition P. Error occurs if device D has no
4158 - "D" or "D:": device D partition 1 if device D has partition
4159 table, or the whole device D if has no partition
4161 - "D:auto": first partition in device D with bootable flag set.
4162 If none, first valid partition in device D. If no
4163 partition table then means device D.
4167 It's a string of the FAT file name. This file use to store the
4171 This should be defined. Otherwise it cannot save the environment file.
4173 - CONFIG_ENV_IS_IN_MMC:
4175 Define this if you have an MMC device which you want to use for the
4178 - CONFIG_SYS_MMC_ENV_DEV:
4180 Specifies which MMC device the environment is stored in.
4182 - CONFIG_SYS_MMC_ENV_PART (optional):
4184 Specifies which MMC partition the environment is stored in. If not
4185 set, defaults to partition 0, the user area. Common values might be
4186 1 (first MMC boot partition), 2 (second MMC boot partition).
4188 - CONFIG_ENV_OFFSET:
4191 These two #defines specify the offset and size of the environment
4192 area within the specified MMC device.
4194 If offset is positive (the usual case), it is treated as relative to
4195 the start of the MMC partition. If offset is negative, it is treated
4196 as relative to the end of the MMC partition. This can be useful if
4197 your board may be fitted with different MMC devices, which have
4198 different sizes for the MMC partitions, and you always want the
4199 environment placed at the very end of the partition, to leave the
4200 maximum possible space before it, to store other data.
4202 These two values are in units of bytes, but must be aligned to an
4203 MMC sector boundary.
4205 - CONFIG_ENV_OFFSET_REDUND (optional):
4207 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4208 hold a redundant copy of the environment data. This provides a
4209 valid backup copy in case the other copy is corrupted, e.g. due
4210 to a power failure during a "saveenv" operation.
4212 This value may also be positive or negative; this is handled in the
4213 same way as CONFIG_ENV_OFFSET.
4215 This value is also in units of bytes, but must also be aligned to
4216 an MMC sector boundary.
4218 - CONFIG_ENV_SIZE_REDUND (optional):
4220 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4221 set. If this value is set, it must be set to the same value as
4224 - CONFIG_SYS_SPI_INIT_OFFSET
4226 Defines offset to the initial SPI buffer area in DPRAM. The
4227 area is used at an early stage (ROM part) if the environment
4228 is configured to reside in the SPI EEPROM: We need a 520 byte
4229 scratch DPRAM area. It is used between the two initialization
4230 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4231 to be a good choice since it makes it far enough from the
4232 start of the data area as well as from the stack pointer.
4234 Please note that the environment is read-only until the monitor
4235 has been relocated to RAM and a RAM copy of the environment has been
4236 created; also, when using EEPROM you will have to use getenv_f()
4237 until then to read environment variables.
4239 The environment is protected by a CRC32 checksum. Before the monitor
4240 is relocated into RAM, as a result of a bad CRC you will be working
4241 with the compiled-in default environment - *silently*!!! [This is
4242 necessary, because the first environment variable we need is the
4243 "baudrate" setting for the console - if we have a bad CRC, we don't
4244 have any device yet where we could complain.]
4246 Note: once the monitor has been relocated, then it will complain if
4247 the default environment is used; a new CRC is computed as soon as you
4248 use the "saveenv" command to store a valid environment.
4250 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4251 Echo the inverted Ethernet link state to the fault LED.
4253 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4254 also needs to be defined.
4256 - CONFIG_SYS_FAULT_MII_ADDR:
4257 MII address of the PHY to check for the Ethernet link state.
4259 - CONFIG_NS16550_MIN_FUNCTIONS:
4260 Define this if you desire to only have use of the NS16550_init
4261 and NS16550_putc functions for the serial driver located at
4262 drivers/serial/ns16550.c. This option is useful for saving
4263 space for already greatly restricted images, including but not
4264 limited to NAND_SPL configurations.
4266 - CONFIG_DISPLAY_BOARDINFO
4267 Display information about the board that U-Boot is running on
4268 when U-Boot starts up. The board function checkboard() is called
4271 - CONFIG_DISPLAY_BOARDINFO_LATE
4272 Similar to the previous option, but display this information
4273 later, once stdio is running and output goes to the LCD, if
4276 - CONFIG_BOARD_SIZE_LIMIT:
4277 Maximum size of the U-Boot image. When defined, the
4278 build system checks that the actual size does not
4281 Low Level (hardware related) configuration options:
4282 ---------------------------------------------------
4284 - CONFIG_SYS_CACHELINE_SIZE:
4285 Cache Line Size of the CPU.
4287 - CONFIG_SYS_DEFAULT_IMMR:
4288 Default address of the IMMR after system reset.
4290 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4291 and RPXsuper) to be able to adjust the position of
4292 the IMMR register after a reset.
4294 - CONFIG_SYS_CCSRBAR_DEFAULT:
4295 Default (power-on reset) physical address of CCSR on Freescale
4298 - CONFIG_SYS_CCSRBAR:
4299 Virtual address of CCSR. On a 32-bit build, this is typically
4300 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4302 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4303 for cross-platform code that uses that macro instead.
4305 - CONFIG_SYS_CCSRBAR_PHYS:
4306 Physical address of CCSR. CCSR can be relocated to a new
4307 physical address, if desired. In this case, this macro should
4308 be set to that address. Otherwise, it should be set to the
4309 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4310 is typically relocated on 36-bit builds. It is recommended
4311 that this macro be defined via the _HIGH and _LOW macros:
4313 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4314 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4316 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4317 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4318 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4319 used in assembly code, so it must not contain typecasts or
4320 integer size suffixes (e.g. "ULL").
4322 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4323 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4324 used in assembly code, so it must not contain typecasts or
4325 integer size suffixes (e.g. "ULL").
4327 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4328 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4329 forced to a value that ensures that CCSR is not relocated.
4331 - Floppy Disk Support:
4332 CONFIG_SYS_FDC_DRIVE_NUMBER
4334 the default drive number (default value 0)
4336 CONFIG_SYS_ISA_IO_STRIDE
4338 defines the spacing between FDC chipset registers
4341 CONFIG_SYS_ISA_IO_OFFSET
4343 defines the offset of register from address. It
4344 depends on which part of the data bus is connected to
4345 the FDC chipset. (default value 0)
4347 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4348 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4351 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4352 fdc_hw_init() is called at the beginning of the FDC
4353 setup. fdc_hw_init() must be provided by the board
4354 source code. It is used to make hardware-dependent
4358 Most IDE controllers were designed to be connected with PCI
4359 interface. Only few of them were designed for AHB interface.
4360 When software is doing ATA command and data transfer to
4361 IDE devices through IDE-AHB controller, some additional
4362 registers accessing to these kind of IDE-AHB controller
4365 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4366 DO NOT CHANGE unless you know exactly what you're
4367 doing! (11-4) [MPC8xx/82xx systems only]
4369 - CONFIG_SYS_INIT_RAM_ADDR:
4371 Start address of memory area that can be used for
4372 initial data and stack; please note that this must be
4373 writable memory that is working WITHOUT special
4374 initialization, i. e. you CANNOT use normal RAM which
4375 will become available only after programming the
4376 memory controller and running certain initialization
4379 U-Boot uses the following memory types:
4380 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4381 - MPC824X: data cache
4382 - PPC4xx: data cache
4384 - CONFIG_SYS_GBL_DATA_OFFSET:
4386 Offset of the initial data structure in the memory
4387 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4388 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4389 data is located at the end of the available space
4390 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4391 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4392 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4393 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4396 On the MPC824X (or other systems that use the data
4397 cache for initial memory) the address chosen for
4398 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4399 point to an otherwise UNUSED address space between
4400 the top of RAM and the start of the PCI space.
4402 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4404 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4406 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4408 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4410 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4412 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4414 - CONFIG_SYS_OR_TIMING_SDRAM:
4417 - CONFIG_SYS_MAMR_PTA:
4418 periodic timer for refresh
4420 - CONFIG_SYS_DER: Debug Event Register (37-47)
4422 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4423 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4424 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4425 CONFIG_SYS_BR1_PRELIM:
4426 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4428 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4429 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4430 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4431 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4433 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4434 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4435 Machine Mode Register and Memory Periodic Timer
4436 Prescaler definitions (SDRAM timing)
4438 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4439 enable I2C microcode relocation patch (MPC8xx);
4440 define relocation offset in DPRAM [DSP2]
4442 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4443 enable SMC microcode relocation patch (MPC8xx);
4444 define relocation offset in DPRAM [SMC1]
4446 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4447 enable SPI microcode relocation patch (MPC8xx);
4448 define relocation offset in DPRAM [SCC4]
4450 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4451 Offset of the bootmode word in DPRAM used by post
4452 (Power On Self Tests). This definition overrides
4453 #define'd default value in commproc.h resp.
4456 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4457 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4458 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4459 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4460 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4461 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4462 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4463 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4464 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4466 - CONFIG_PCI_DISABLE_PCIE:
4467 Disable PCI-Express on systems where it is supported but not
4470 - CONFIG_PCI_ENUM_ONLY
4471 Only scan through and get the devices on the buses.
4472 Don't do any setup work, presumably because someone or
4473 something has already done it, and we don't need to do it
4474 a second time. Useful for platforms that are pre-booted
4475 by coreboot or similar.
4477 - CONFIG_PCI_INDIRECT_BRIDGE:
4478 Enable support for indirect PCI bridges.
4481 Chip has SRIO or not
4484 Board has SRIO 1 port available
4487 Board has SRIO 2 port available
4489 - CONFIG_SRIO_PCIE_BOOT_MASTER
4490 Board can support master function for Boot from SRIO and PCIE
4492 - CONFIG_SYS_SRIOn_MEM_VIRT:
4493 Virtual Address of SRIO port 'n' memory region
4495 - CONFIG_SYS_SRIOn_MEM_PHYS:
4496 Physical Address of SRIO port 'n' memory region
4498 - CONFIG_SYS_SRIOn_MEM_SIZE:
4499 Size of SRIO port 'n' memory region
4501 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4502 Defined to tell the NAND controller that the NAND chip is using
4504 Not all NAND drivers use this symbol.
4505 Example of drivers that use it:
4506 - drivers/mtd/nand/ndfc.c
4507 - drivers/mtd/nand/mxc_nand.c
4509 - CONFIG_SYS_NDFC_EBC0_CFG
4510 Sets the EBC0_CFG register for the NDFC. If not defined
4511 a default value will be used.
4514 Get DDR timing information from an I2C EEPROM. Common
4515 with pluggable memory modules such as SODIMMs
4518 I2C address of the SPD EEPROM
4520 - CONFIG_SYS_SPD_BUS_NUM
4521 If SPD EEPROM is on an I2C bus other than the first
4522 one, specify here. Note that the value must resolve
4523 to something your driver can deal with.
4525 - CONFIG_SYS_DDR_RAW_TIMING
4526 Get DDR timing information from other than SPD. Common with
4527 soldered DDR chips onboard without SPD. DDR raw timing
4528 parameters are extracted from datasheet and hard-coded into
4529 header files or board specific files.
4531 - CONFIG_FSL_DDR_INTERACTIVE
4532 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4534 - CONFIG_FSL_DDR_SYNC_REFRESH
4535 Enable sync of refresh for multiple controllers.
4537 - CONFIG_FSL_DDR_BIST
4538 Enable built-in memory test for Freescale DDR controllers.
4540 - CONFIG_SYS_83XX_DDR_USES_CS0
4541 Only for 83xx systems. If specified, then DDR should
4542 be configured using CS0 and CS1 instead of CS2 and CS3.
4544 - CONFIG_ETHER_ON_FEC[12]
4545 Define to enable FEC[12] on a 8xx series processor.
4547 - CONFIG_FEC[12]_PHY
4548 Define to the hardcoded PHY address which corresponds
4549 to the given FEC; i. e.
4550 #define CONFIG_FEC1_PHY 4
4551 means that the PHY with address 4 is connected to FEC1
4553 When set to -1, means to probe for first available.
4555 - CONFIG_FEC[12]_PHY_NORXERR
4556 The PHY does not have a RXERR line (RMII only).
4557 (so program the FEC to ignore it).
4560 Enable RMII mode for all FECs.
4561 Note that this is a global option, we can't
4562 have one FEC in standard MII mode and another in RMII mode.
4564 - CONFIG_CRC32_VERIFY
4565 Add a verify option to the crc32 command.
4568 => crc32 -v <address> <count> <crc32>
4570 Where address/count indicate a memory area
4571 and crc32 is the correct crc32 which the
4575 Add the "loopw" memory command. This only takes effect if
4576 the memory commands are activated globally (CONFIG_CMD_MEM).
4579 Add the "mdc" and "mwc" memory commands. These are cyclic
4584 This command will print 4 bytes (10,11,12,13) each 500 ms.
4586 => mwc.l 100 12345678 10
4587 This command will write 12345678 to address 100 all 10 ms.
4589 This only takes effect if the memory commands are activated
4590 globally (CONFIG_CMD_MEM).
4592 - CONFIG_SKIP_LOWLEVEL_INIT
4593 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4594 low level initializations (like setting up the memory
4595 controller) are omitted and/or U-Boot does not
4596 relocate itself into RAM.
4598 Normally this variable MUST NOT be defined. The only
4599 exception is when U-Boot is loaded (to RAM) by some
4600 other boot loader or by a debugger which performs
4601 these initializations itself.
4603 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4604 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4605 to be skipped. The normal CP15 init (such as enabling the
4606 instruction cache) is still performed.
4609 Modifies the behaviour of start.S when compiling a loader
4610 that is executed before the actual U-Boot. E.g. when
4611 compiling a NAND SPL.
4614 Modifies the behaviour of start.S when compiling a loader
4615 that is executed after the SPL and before the actual U-Boot.
4616 It is loaded by the SPL.
4618 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4619 Only for 85xx systems. If this variable is specified, the section
4620 .resetvec is not kept and the section .bootpg is placed in the
4621 previous 4k of the .text section.
4623 - CONFIG_ARCH_MAP_SYSMEM
4624 Generally U-Boot (and in particular the md command) uses
4625 effective address. It is therefore not necessary to regard
4626 U-Boot address as virtual addresses that need to be translated
4627 to physical addresses. However, sandbox requires this, since
4628 it maintains its own little RAM buffer which contains all
4629 addressable memory. This option causes some memory accesses
4630 to be mapped through map_sysmem() / unmap_sysmem().
4632 - CONFIG_USE_ARCH_MEMCPY
4633 CONFIG_USE_ARCH_MEMSET
4634 If these options are used a optimized version of memcpy/memset will
4635 be used if available. These functions may be faster under some
4636 conditions but may increase the binary size.
4638 - CONFIG_X86_RESET_VECTOR
4639 If defined, the x86 reset vector code is included. This is not
4640 needed when U-Boot is running from Coreboot.
4643 Defines the MPU clock speed (in MHz).
4645 NOTE : currently only supported on AM335x platforms.
4647 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4648 Enables the RTC32K OSC on AM33xx based plattforms
4650 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4651 Option to disable subpage write in NAND driver
4652 driver that uses this:
4653 drivers/mtd/nand/davinci_nand.c
4655 Freescale QE/FMAN Firmware Support:
4656 -----------------------------------
4658 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4659 loading of "firmware", which is encoded in the QE firmware binary format.
4660 This firmware often needs to be loaded during U-Boot booting, so macros
4661 are used to identify the storage device (NOR flash, SPI, etc) and the address
4664 - CONFIG_SYS_FMAN_FW_ADDR
4665 The address in the storage device where the FMAN microcode is located. The
4666 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4669 - CONFIG_SYS_QE_FW_ADDR
4670 The address in the storage device where the QE microcode is located. The
4671 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4674 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4675 The maximum possible size of the firmware. The firmware binary format
4676 has a field that specifies the actual size of the firmware, but it
4677 might not be possible to read any part of the firmware unless some
4678 local storage is allocated to hold the entire firmware first.
4680 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4681 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4682 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4683 virtual address in NOR flash.
4685 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4686 Specifies that QE/FMAN firmware is located in NAND flash.
4687 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4689 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4690 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4691 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4693 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4694 Specifies that QE/FMAN firmware is located in the remote (master)
4695 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4696 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4697 window->master inbound window->master LAW->the ucode address in
4698 master's memory space.
4700 Freescale Layerscape Management Complex Firmware Support:
4701 ---------------------------------------------------------
4702 The Freescale Layerscape Management Complex (MC) supports the loading of
4704 This firmware often needs to be loaded during U-Boot booting, so macros
4705 are used to identify the storage device (NOR flash, SPI, etc) and the address
4708 - CONFIG_FSL_MC_ENET
4709 Enable the MC driver for Layerscape SoCs.
4711 Freescale Layerscape Debug Server Support:
4712 -------------------------------------------
4713 The Freescale Layerscape Debug Server Support supports the loading of
4714 "Debug Server firmware" and triggering SP boot-rom.
4715 This firmware often needs to be loaded during U-Boot booting.
4717 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4718 Define alignment of reserved memory MC requires
4723 In order to achieve reproducible builds, timestamps used in the U-Boot build
4724 process have to be set to a fixed value.
4726 This is done using the SOURCE_DATE_EPOCH environment variable.
4727 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4728 option for U-Boot or an environment variable in U-Boot.
4730 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4732 Building the Software:
4733 ======================
4735 Building U-Boot has been tested in several native build environments
4736 and in many different cross environments. Of course we cannot support
4737 all possibly existing versions of cross development tools in all
4738 (potentially obsolete) versions. In case of tool chain problems we
4739 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4740 which is extensively used to build and test U-Boot.
4742 If you are not using a native environment, it is assumed that you
4743 have GNU cross compiling tools available in your path. In this case,
4744 you must set the environment variable CROSS_COMPILE in your shell.
4745 Note that no changes to the Makefile or any other source files are
4746 necessary. For example using the ELDK on a 4xx CPU, please enter:
4748 $ CROSS_COMPILE=ppc_4xx-
4749 $ export CROSS_COMPILE
4751 Note: If you wish to generate Windows versions of the utilities in
4752 the tools directory you can use the MinGW toolchain
4753 (http://www.mingw.org). Set your HOST tools to the MinGW
4754 toolchain and execute 'make tools'. For example:
4756 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4758 Binaries such as tools/mkimage.exe will be created which can
4759 be executed on computers running Windows.
4761 U-Boot is intended to be simple to build. After installing the
4762 sources you must configure U-Boot for one specific board type. This
4767 where "NAME_defconfig" is the name of one of the existing configu-
4768 rations; see boards.cfg for supported names.
4770 Note: for some board special configuration names may exist; check if
4771 additional information is available from the board vendor; for
4772 instance, the TQM823L systems are available without (standard)
4773 or with LCD support. You can select such additional "features"
4774 when choosing the configuration, i. e.
4776 make TQM823L_defconfig
4777 - will configure for a plain TQM823L, i. e. no LCD support
4779 make TQM823L_LCD_defconfig
4780 - will configure for a TQM823L with U-Boot console on LCD
4785 Finally, type "make all", and you should get some working U-Boot
4786 images ready for download to / installation on your system:
4788 - "u-boot.bin" is a raw binary image
4789 - "u-boot" is an image in ELF binary format
4790 - "u-boot.srec" is in Motorola S-Record format
4792 By default the build is performed locally and the objects are saved
4793 in the source directory. One of the two methods can be used to change
4794 this behavior and build U-Boot to some external directory:
4796 1. Add O= to the make command line invocations:
4798 make O=/tmp/build distclean
4799 make O=/tmp/build NAME_defconfig
4800 make O=/tmp/build all
4802 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4804 export KBUILD_OUTPUT=/tmp/build
4809 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4813 Please be aware that the Makefiles assume you are using GNU make, so
4814 for instance on NetBSD you might need to use "gmake" instead of
4818 If the system board that you have is not listed, then you will need
4819 to port U-Boot to your hardware platform. To do this, follow these
4822 1. Create a new directory to hold your board specific code. Add any
4823 files you need. In your board directory, you will need at least
4824 the "Makefile" and a "<board>.c".
4825 2. Create a new configuration file "include/configs/<board>.h" for
4827 3. If you're porting U-Boot to a new CPU, then also create a new
4828 directory to hold your CPU specific code. Add any files you need.
4829 4. Run "make <board>_defconfig" with your new name.
4830 5. Type "make", and you should get a working "u-boot.srec" file
4831 to be installed on your target system.
4832 6. Debug and solve any problems that might arise.
4833 [Of course, this last step is much harder than it sounds.]
4836 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4837 ==============================================================
4839 If you have modified U-Boot sources (for instance added a new board
4840 or support for new devices, a new CPU, etc.) you are expected to
4841 provide feedback to the other developers. The feedback normally takes
4842 the form of a "patch", i. e. a context diff against a certain (latest
4843 official or latest in the git repository) version of U-Boot sources.
4845 But before you submit such a patch, please verify that your modifi-
4846 cation did not break existing code. At least make sure that *ALL* of
4847 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4848 just run the buildman script (tools/buildman/buildman), which will
4849 configure and build U-Boot for ALL supported system. Be warned, this
4850 will take a while. Please see the buildman README, or run 'buildman -H'
4854 See also "U-Boot Porting Guide" below.
4857 Monitor Commands - Overview:
4858 ============================
4860 go - start application at address 'addr'
4861 run - run commands in an environment variable
4862 bootm - boot application image from memory
4863 bootp - boot image via network using BootP/TFTP protocol
4864 bootz - boot zImage from memory
4865 tftpboot- boot image via network using TFTP protocol
4866 and env variables "ipaddr" and "serverip"
4867 (and eventually "gatewayip")
4868 tftpput - upload a file via network using TFTP protocol
4869 rarpboot- boot image via network using RARP/TFTP protocol
4870 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4871 loads - load S-Record file over serial line
4872 loadb - load binary file over serial line (kermit mode)
4874 mm - memory modify (auto-incrementing)
4875 nm - memory modify (constant address)
4876 mw - memory write (fill)
4878 cmp - memory compare
4879 crc32 - checksum calculation
4880 i2c - I2C sub-system
4881 sspi - SPI utility commands
4882 base - print or set address offset
4883 printenv- print environment variables
4884 setenv - set environment variables
4885 saveenv - save environment variables to persistent storage
4886 protect - enable or disable FLASH write protection
4887 erase - erase FLASH memory
4888 flinfo - print FLASH memory information
4889 nand - NAND memory operations (see doc/README.nand)
4890 bdinfo - print Board Info structure
4891 iminfo - print header information for application image
4892 coninfo - print console devices and informations
4893 ide - IDE sub-system
4894 loop - infinite loop on address range
4895 loopw - infinite write loop on address range
4896 mtest - simple RAM test
4897 icache - enable or disable instruction cache
4898 dcache - enable or disable data cache
4899 reset - Perform RESET of the CPU
4900 echo - echo args to console
4901 version - print monitor version
4902 help - print online help
4903 ? - alias for 'help'
4906 Monitor Commands - Detailed Description:
4907 ========================================
4911 For now: just type "help <command>".
4914 Environment Variables:
4915 ======================
4917 U-Boot supports user configuration using Environment Variables which
4918 can be made persistent by saving to Flash memory.
4920 Environment Variables are set using "setenv", printed using
4921 "printenv", and saved to Flash using "saveenv". Using "setenv"
4922 without a value can be used to delete a variable from the
4923 environment. As long as you don't save the environment you are
4924 working with an in-memory copy. In case the Flash area containing the
4925 environment is erased by accident, a default environment is provided.
4927 Some configuration options can be set using Environment Variables.
4929 List of environment variables (most likely not complete):
4931 baudrate - see CONFIG_BAUDRATE
4933 bootdelay - see CONFIG_BOOTDELAY
4935 bootcmd - see CONFIG_BOOTCOMMAND
4937 bootargs - Boot arguments when booting an RTOS image
4939 bootfile - Name of the image to load with TFTP
4941 bootm_low - Memory range available for image processing in the bootm
4942 command can be restricted. This variable is given as
4943 a hexadecimal number and defines lowest address allowed
4944 for use by the bootm command. See also "bootm_size"
4945 environment variable. Address defined by "bootm_low" is
4946 also the base of the initial memory mapping for the Linux
4947 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4950 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4951 This variable is given as a hexadecimal number and it
4952 defines the size of the memory region starting at base
4953 address bootm_low that is accessible by the Linux kernel
4954 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4955 as the default value if it is defined, and bootm_size is
4958 bootm_size - Memory range available for image processing in the bootm
4959 command can be restricted. This variable is given as
4960 a hexadecimal number and defines the size of the region
4961 allowed for use by the bootm command. See also "bootm_low"
4962 environment variable.
4964 updatefile - Location of the software update file on a TFTP server, used
4965 by the automatic software update feature. Please refer to
4966 documentation in doc/README.update for more details.
4968 autoload - if set to "no" (any string beginning with 'n'),
4969 "bootp" will just load perform a lookup of the
4970 configuration from the BOOTP server, but not try to
4971 load any image using TFTP
4973 autostart - if set to "yes", an image loaded using the "bootp",
4974 "rarpboot", "tftpboot" or "diskboot" commands will
4975 be automatically started (by internally calling
4978 If set to "no", a standalone image passed to the
4979 "bootm" command will be copied to the load address
4980 (and eventually uncompressed), but NOT be started.
4981 This can be used to load and uncompress arbitrary
4984 fdt_high - if set this restricts the maximum address that the
4985 flattened device tree will be copied into upon boot.
4986 For example, if you have a system with 1 GB memory
4987 at physical address 0x10000000, while Linux kernel
4988 only recognizes the first 704 MB as low memory, you
4989 may need to set fdt_high as 0x3C000000 to have the
4990 device tree blob be copied to the maximum address
4991 of the 704 MB low memory, so that Linux kernel can
4992 access it during the boot procedure.
4994 If this is set to the special value 0xFFFFFFFF then
4995 the fdt will not be copied at all on boot. For this
4996 to work it must reside in writable memory, have
4997 sufficient padding on the end of it for u-boot to
4998 add the information it needs into it, and the memory
4999 must be accessible by the kernel.
5001 fdtcontroladdr- if set this is the address of the control flattened
5002 device tree used by U-Boot when CONFIG_OF_CONTROL is
5005 i2cfast - (PPC405GP|PPC405EP only)
5006 if set to 'y' configures Linux I2C driver for fast
5007 mode (400kHZ). This environment variable is used in
5008 initialization code. So, for changes to be effective
5009 it must be saved and board must be reset.
5011 initrd_high - restrict positioning of initrd images:
5012 If this variable is not set, initrd images will be
5013 copied to the highest possible address in RAM; this
5014 is usually what you want since it allows for
5015 maximum initrd size. If for some reason you want to
5016 make sure that the initrd image is loaded below the
5017 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5018 variable to a value of "no" or "off" or "0".
5019 Alternatively, you can set it to a maximum upper
5020 address to use (U-Boot will still check that it
5021 does not overwrite the U-Boot stack and data).
5023 For instance, when you have a system with 16 MB
5024 RAM, and want to reserve 4 MB from use by Linux,
5025 you can do this by adding "mem=12M" to the value of
5026 the "bootargs" variable. However, now you must make
5027 sure that the initrd image is placed in the first
5028 12 MB as well - this can be done with
5030 setenv initrd_high 00c00000
5032 If you set initrd_high to 0xFFFFFFFF, this is an
5033 indication to U-Boot that all addresses are legal
5034 for the Linux kernel, including addresses in flash
5035 memory. In this case U-Boot will NOT COPY the
5036 ramdisk at all. This may be useful to reduce the
5037 boot time on your system, but requires that this
5038 feature is supported by your Linux kernel.
5040 ipaddr - IP address; needed for tftpboot command
5042 loadaddr - Default load address for commands like "bootp",
5043 "rarpboot", "tftpboot", "loadb" or "diskboot"
5045 loads_echo - see CONFIG_LOADS_ECHO
5047 serverip - TFTP server IP address; needed for tftpboot command
5049 bootretry - see CONFIG_BOOT_RETRY_TIME
5051 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5053 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5055 ethprime - controls which interface is used first.
5057 ethact - controls which interface is currently active.
5058 For example you can do the following
5060 => setenv ethact FEC
5061 => ping 192.168.0.1 # traffic sent on FEC
5062 => setenv ethact SCC
5063 => ping 10.0.0.1 # traffic sent on SCC
5065 ethrotate - When set to "no" U-Boot does not go through all
5066 available network interfaces.
5067 It just stays at the currently selected interface.
5069 netretry - When set to "no" each network operation will
5070 either succeed or fail without retrying.
5071 When set to "once" the network operation will
5072 fail when all the available network interfaces
5073 are tried once without success.
5074 Useful on scripts which control the retry operation
5077 npe_ucode - set load address for the NPE microcode
5079 silent_linux - If set then Linux will be told to boot silently, by
5080 changing the console to be empty. If "yes" it will be
5081 made silent. If "no" it will not be made silent. If
5082 unset, then it will be made silent if the U-Boot console
5085 tftpsrcp - If this is set, the value is used for TFTP's
5088 tftpdstp - If this is set, the value is used for TFTP's UDP
5089 destination port instead of the Well Know Port 69.
5091 tftpblocksize - Block size to use for TFTP transfers; if not set,
5092 we use the TFTP server's default block size
5094 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5095 seconds, minimum value is 1000 = 1 second). Defines
5096 when a packet is considered to be lost so it has to
5097 be retransmitted. The default is 5000 = 5 seconds.
5098 Lowering this value may make downloads succeed
5099 faster in networks with high packet loss rates or
5100 with unreliable TFTP servers.
5102 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5103 unit, minimum value = 0). Defines how many timeouts
5104 can happen during a single file transfer before that
5105 transfer is aborted. The default is 10, and 0 means
5106 'no timeouts allowed'. Increasing this value may help
5107 downloads succeed with high packet loss rates, or with
5108 unreliable TFTP servers or client hardware.
5110 vlan - When set to a value < 4095 the traffic over
5111 Ethernet is encapsulated/received over 802.1q
5114 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5115 Unsigned value, in milliseconds. If not set, the period will
5116 be either the default (28000), or a value based on
5117 CONFIG_NET_RETRY_COUNT, if defined. This value has
5118 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5120 The following image location variables contain the location of images
5121 used in booting. The "Image" column gives the role of the image and is
5122 not an environment variable name. The other columns are environment
5123 variable names. "File Name" gives the name of the file on a TFTP
5124 server, "RAM Address" gives the location in RAM the image will be
5125 loaded to, and "Flash Location" gives the image's address in NOR
5126 flash or offset in NAND flash.
5128 *Note* - these variables don't have to be defined for all boards, some
5129 boards currently use other variables for these purposes, and some
5130 boards use these variables for other purposes.
5132 Image File Name RAM Address Flash Location
5133 ----- --------- ----------- --------------
5134 u-boot u-boot u-boot_addr_r u-boot_addr
5135 Linux kernel bootfile kernel_addr_r kernel_addr
5136 device tree blob fdtfile fdt_addr_r fdt_addr
5137 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5139 The following environment variables may be used and automatically
5140 updated by the network boot commands ("bootp" and "rarpboot"),
5141 depending the information provided by your boot server:
5143 bootfile - see above
5144 dnsip - IP address of your Domain Name Server
5145 dnsip2 - IP address of your secondary Domain Name Server
5146 gatewayip - IP address of the Gateway (Router) to use
5147 hostname - Target hostname
5149 netmask - Subnet Mask
5150 rootpath - Pathname of the root filesystem on the NFS server
5151 serverip - see above
5154 There are two special Environment Variables:
5156 serial# - contains hardware identification information such
5157 as type string and/or serial number
5158 ethaddr - Ethernet address
5160 These variables can be set only once (usually during manufacturing of
5161 the board). U-Boot refuses to delete or overwrite these variables
5162 once they have been set once.
5165 Further special Environment Variables:
5167 ver - Contains the U-Boot version string as printed
5168 with the "version" command. This variable is
5169 readonly (see CONFIG_VERSION_VARIABLE).
5172 Please note that changes to some configuration parameters may take
5173 only effect after the next boot (yes, that's just like Windoze :-).
5176 Callback functions for environment variables:
5177 ---------------------------------------------
5179 For some environment variables, the behavior of u-boot needs to change
5180 when their values are changed. This functionality allows functions to
5181 be associated with arbitrary variables. On creation, overwrite, or
5182 deletion, the callback will provide the opportunity for some side
5183 effect to happen or for the change to be rejected.
5185 The callbacks are named and associated with a function using the
5186 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5188 These callbacks are associated with variables in one of two ways. The
5189 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5190 in the board configuration to a string that defines a list of
5191 associations. The list must be in the following format:
5193 entry = variable_name[:callback_name]
5196 If the callback name is not specified, then the callback is deleted.
5197 Spaces are also allowed anywhere in the list.
5199 Callbacks can also be associated by defining the ".callbacks" variable
5200 with the same list format above. Any association in ".callbacks" will
5201 override any association in the static list. You can define
5202 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5203 ".callbacks" environment variable in the default or embedded environment.
5205 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5206 regular expression. This allows multiple variables to be connected to
5207 the same callback without explicitly listing them all out.
5210 Command Line Parsing:
5211 =====================
5213 There are two different command line parsers available with U-Boot:
5214 the old "simple" one, and the much more powerful "hush" shell:
5216 Old, simple command line parser:
5217 --------------------------------
5219 - supports environment variables (through setenv / saveenv commands)
5220 - several commands on one line, separated by ';'
5221 - variable substitution using "... ${name} ..." syntax
5222 - special characters ('$', ';') can be escaped by prefixing with '\',
5224 setenv bootcmd bootm \${address}
5225 - You can also escape text by enclosing in single apostrophes, for example:
5226 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5231 - similar to Bourne shell, with control structures like
5232 if...then...else...fi, for...do...done; while...do...done,
5233 until...do...done, ...
5234 - supports environment ("global") variables (through setenv / saveenv
5235 commands) and local shell variables (through standard shell syntax
5236 "name=value"); only environment variables can be used with "run"
5242 (1) If a command line (or an environment variable executed by a "run"
5243 command) contains several commands separated by semicolon, and
5244 one of these commands fails, then the remaining commands will be
5247 (2) If you execute several variables with one call to run (i. e.
5248 calling run with a list of variables as arguments), any failing
5249 command will cause "run" to terminate, i. e. the remaining
5250 variables are not executed.
5252 Note for Redundant Ethernet Interfaces:
5253 =======================================
5255 Some boards come with redundant Ethernet interfaces; U-Boot supports
5256 such configurations and is capable of automatic selection of a
5257 "working" interface when needed. MAC assignment works as follows:
5259 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5260 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5261 "eth1addr" (=>eth1), "eth2addr", ...
5263 If the network interface stores some valid MAC address (for instance
5264 in SROM), this is used as default address if there is NO correspon-
5265 ding setting in the environment; if the corresponding environment
5266 variable is set, this overrides the settings in the card; that means:
5268 o If the SROM has a valid MAC address, and there is no address in the
5269 environment, the SROM's address is used.
5271 o If there is no valid address in the SROM, and a definition in the
5272 environment exists, then the value from the environment variable is
5275 o If both the SROM and the environment contain a MAC address, and
5276 both addresses are the same, this MAC address is used.
5278 o If both the SROM and the environment contain a MAC address, and the
5279 addresses differ, the value from the environment is used and a
5282 o If neither SROM nor the environment contain a MAC address, an error
5283 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5284 a random, locally-assigned MAC is used.
5286 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5287 will be programmed into hardware as part of the initialization process. This
5288 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5289 The naming convention is as follows:
5290 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5295 U-Boot is capable of booting (and performing other auxiliary operations on)
5296 images in two formats:
5298 New uImage format (FIT)
5299 -----------------------
5301 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5302 to Flattened Device Tree). It allows the use of images with multiple
5303 components (several kernels, ramdisks, etc.), with contents protected by
5304 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5310 Old image format is based on binary files which can be basically anything,
5311 preceded by a special header; see the definitions in include/image.h for
5312 details; basically, the header defines the following image properties:
5314 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5315 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5316 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5317 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5319 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5320 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5321 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5322 * Compression Type (uncompressed, gzip, bzip2)
5328 The header is marked by a special Magic Number, and both the header
5329 and the data portions of the image are secured against corruption by
5336 Although U-Boot should support any OS or standalone application
5337 easily, the main focus has always been on Linux during the design of
5340 U-Boot includes many features that so far have been part of some
5341 special "boot loader" code within the Linux kernel. Also, any
5342 "initrd" images to be used are no longer part of one big Linux image;
5343 instead, kernel and "initrd" are separate images. This implementation
5344 serves several purposes:
5346 - the same features can be used for other OS or standalone
5347 applications (for instance: using compressed images to reduce the
5348 Flash memory footprint)
5350 - it becomes much easier to port new Linux kernel versions because
5351 lots of low-level, hardware dependent stuff are done by U-Boot
5353 - the same Linux kernel image can now be used with different "initrd"
5354 images; of course this also means that different kernel images can
5355 be run with the same "initrd". This makes testing easier (you don't
5356 have to build a new "zImage.initrd" Linux image when you just
5357 change a file in your "initrd"). Also, a field-upgrade of the
5358 software is easier now.
5364 Porting Linux to U-Boot based systems:
5365 ---------------------------------------
5367 U-Boot cannot save you from doing all the necessary modifications to
5368 configure the Linux device drivers for use with your target hardware
5369 (no, we don't intend to provide a full virtual machine interface to
5372 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5374 Just make sure your machine specific header file (for instance
5375 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5376 Information structure as we define in include/asm-<arch>/u-boot.h,
5377 and make sure that your definition of IMAP_ADDR uses the same value
5378 as your U-Boot configuration in CONFIG_SYS_IMMR.
5380 Note that U-Boot now has a driver model, a unified model for drivers.
5381 If you are adding a new driver, plumb it into driver model. If there
5382 is no uclass available, you are encouraged to create one. See
5386 Configuring the Linux kernel:
5387 -----------------------------
5389 No specific requirements for U-Boot. Make sure you have some root
5390 device (initial ramdisk, NFS) for your target system.
5393 Building a Linux Image:
5394 -----------------------
5396 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5397 not used. If you use recent kernel source, a new build target
5398 "uImage" will exist which automatically builds an image usable by
5399 U-Boot. Most older kernels also have support for a "pImage" target,
5400 which was introduced for our predecessor project PPCBoot and uses a
5401 100% compatible format.
5405 make TQM850L_defconfig
5410 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5411 encapsulate a compressed Linux kernel image with header information,
5412 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5414 * build a standard "vmlinux" kernel image (in ELF binary format):
5416 * convert the kernel into a raw binary image:
5418 ${CROSS_COMPILE}-objcopy -O binary \
5419 -R .note -R .comment \
5420 -S vmlinux linux.bin
5422 * compress the binary image:
5426 * package compressed binary image for U-Boot:
5428 mkimage -A ppc -O linux -T kernel -C gzip \
5429 -a 0 -e 0 -n "Linux Kernel Image" \
5430 -d linux.bin.gz uImage
5433 The "mkimage" tool can also be used to create ramdisk images for use
5434 with U-Boot, either separated from the Linux kernel image, or
5435 combined into one file. "mkimage" encapsulates the images with a 64
5436 byte header containing information about target architecture,
5437 operating system, image type, compression method, entry points, time
5438 stamp, CRC32 checksums, etc.
5440 "mkimage" can be called in two ways: to verify existing images and
5441 print the header information, or to build new images.
5443 In the first form (with "-l" option) mkimage lists the information
5444 contained in the header of an existing U-Boot image; this includes
5445 checksum verification:
5447 tools/mkimage -l image
5448 -l ==> list image header information
5450 The second form (with "-d" option) is used to build a U-Boot image
5451 from a "data file" which is used as image payload:
5453 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5454 -n name -d data_file image
5455 -A ==> set architecture to 'arch'
5456 -O ==> set operating system to 'os'
5457 -T ==> set image type to 'type'
5458 -C ==> set compression type 'comp'
5459 -a ==> set load address to 'addr' (hex)
5460 -e ==> set entry point to 'ep' (hex)
5461 -n ==> set image name to 'name'
5462 -d ==> use image data from 'datafile'
5464 Right now, all Linux kernels for PowerPC systems use the same load
5465 address (0x00000000), but the entry point address depends on the
5468 - 2.2.x kernels have the entry point at 0x0000000C,
5469 - 2.3.x and later kernels have the entry point at 0x00000000.
5471 So a typical call to build a U-Boot image would read:
5473 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5474 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5475 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5476 > examples/uImage.TQM850L
5477 Image Name: 2.4.4 kernel for TQM850L
5478 Created: Wed Jul 19 02:34:59 2000
5479 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5480 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5481 Load Address: 0x00000000
5482 Entry Point: 0x00000000
5484 To verify the contents of the image (or check for corruption):
5486 -> tools/mkimage -l examples/uImage.TQM850L
5487 Image Name: 2.4.4 kernel for TQM850L
5488 Created: Wed Jul 19 02:34:59 2000
5489 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5490 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5491 Load Address: 0x00000000
5492 Entry Point: 0x00000000
5494 NOTE: for embedded systems where boot time is critical you can trade
5495 speed for memory and install an UNCOMPRESSED image instead: this
5496 needs more space in Flash, but boots much faster since it does not
5497 need to be uncompressed:
5499 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5500 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5501 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5502 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5503 > examples/uImage.TQM850L-uncompressed
5504 Image Name: 2.4.4 kernel for TQM850L
5505 Created: Wed Jul 19 02:34:59 2000
5506 Image Type: PowerPC Linux Kernel Image (uncompressed)
5507 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5508 Load Address: 0x00000000
5509 Entry Point: 0x00000000
5512 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5513 when your kernel is intended to use an initial ramdisk:
5515 -> tools/mkimage -n 'Simple Ramdisk Image' \
5516 > -A ppc -O linux -T ramdisk -C gzip \
5517 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5518 Image Name: Simple Ramdisk Image
5519 Created: Wed Jan 12 14:01:50 2000
5520 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5521 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5522 Load Address: 0x00000000
5523 Entry Point: 0x00000000
5525 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5526 option performs the converse operation of the mkimage's second form (the "-d"
5527 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5530 tools/dumpimage -i image -T type -p position data_file
5531 -i ==> extract from the 'image' a specific 'data_file'
5532 -T ==> set image type to 'type'
5533 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5536 Installing a Linux Image:
5537 -------------------------
5539 To downloading a U-Boot image over the serial (console) interface,
5540 you must convert the image to S-Record format:
5542 objcopy -I binary -O srec examples/image examples/image.srec
5544 The 'objcopy' does not understand the information in the U-Boot
5545 image header, so the resulting S-Record file will be relative to
5546 address 0x00000000. To load it to a given address, you need to
5547 specify the target address as 'offset' parameter with the 'loads'
5550 Example: install the image to address 0x40100000 (which on the
5551 TQM8xxL is in the first Flash bank):
5553 => erase 40100000 401FFFFF
5559 ## Ready for S-Record download ...
5560 ~>examples/image.srec
5561 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5563 15989 15990 15991 15992
5564 [file transfer complete]
5566 ## Start Addr = 0x00000000
5569 You can check the success of the download using the 'iminfo' command;
5570 this includes a checksum verification so you can be sure no data
5571 corruption happened:
5575 ## Checking Image at 40100000 ...
5576 Image Name: 2.2.13 for initrd on TQM850L
5577 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5578 Data Size: 335725 Bytes = 327 kB = 0 MB
5579 Load Address: 00000000
5580 Entry Point: 0000000c
5581 Verifying Checksum ... OK
5587 The "bootm" command is used to boot an application that is stored in
5588 memory (RAM or Flash). In case of a Linux kernel image, the contents
5589 of the "bootargs" environment variable is passed to the kernel as
5590 parameters. You can check and modify this variable using the
5591 "printenv" and "setenv" commands:
5594 => printenv bootargs
5595 bootargs=root=/dev/ram
5597 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5599 => printenv bootargs
5600 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5603 ## Booting Linux kernel at 40020000 ...
5604 Image Name: 2.2.13 for NFS on TQM850L
5605 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5606 Data Size: 381681 Bytes = 372 kB = 0 MB
5607 Load Address: 00000000
5608 Entry Point: 0000000c
5609 Verifying Checksum ... OK
5610 Uncompressing Kernel Image ... OK
5611 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
5612 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5613 time_init: decrementer frequency = 187500000/60
5614 Calibrating delay loop... 49.77 BogoMIPS
5615 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5618 If you want to boot a Linux kernel with initial RAM disk, you pass
5619 the memory addresses of both the kernel and the initrd image (PPBCOOT
5620 format!) to the "bootm" command:
5622 => imi 40100000 40200000
5624 ## Checking Image at 40100000 ...
5625 Image Name: 2.2.13 for initrd on TQM850L
5626 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5627 Data Size: 335725 Bytes = 327 kB = 0 MB
5628 Load Address: 00000000
5629 Entry Point: 0000000c
5630 Verifying Checksum ... OK
5632 ## Checking Image at 40200000 ...
5633 Image Name: Simple Ramdisk Image
5634 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5635 Data Size: 566530 Bytes = 553 kB = 0 MB
5636 Load Address: 00000000
5637 Entry Point: 00000000
5638 Verifying Checksum ... OK
5640 => bootm 40100000 40200000
5641 ## Booting Linux kernel at 40100000 ...
5642 Image Name: 2.2.13 for initrd on TQM850L
5643 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5644 Data Size: 335725 Bytes = 327 kB = 0 MB
5645 Load Address: 00000000
5646 Entry Point: 0000000c
5647 Verifying Checksum ... OK
5648 Uncompressing Kernel Image ... OK
5649 ## Loading RAMDisk Image at 40200000 ...
5650 Image Name: Simple Ramdisk Image
5651 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5652 Data Size: 566530 Bytes = 553 kB = 0 MB
5653 Load Address: 00000000
5654 Entry Point: 00000000
5655 Verifying Checksum ... OK
5656 Loading Ramdisk ... OK
5657 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
5658 Boot arguments: root=/dev/ram
5659 time_init: decrementer frequency = 187500000/60
5660 Calibrating delay loop... 49.77 BogoMIPS
5662 RAMDISK: Compressed image found at block 0
5663 VFS: Mounted root (ext2 filesystem).
5667 Boot Linux and pass a flat device tree:
5670 First, U-Boot must be compiled with the appropriate defines. See the section
5671 titled "Linux Kernel Interface" above for a more in depth explanation. The
5672 following is an example of how to start a kernel and pass an updated
5678 oft=oftrees/mpc8540ads.dtb
5679 => tftp $oftaddr $oft
5680 Speed: 1000, full duplex
5682 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5683 Filename 'oftrees/mpc8540ads.dtb'.
5684 Load address: 0x300000
5687 Bytes transferred = 4106 (100a hex)
5688 => tftp $loadaddr $bootfile
5689 Speed: 1000, full duplex
5691 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5693 Load address: 0x200000
5694 Loading:############
5696 Bytes transferred = 1029407 (fb51f hex)
5701 => bootm $loadaddr - $oftaddr
5702 ## Booting image at 00200000 ...
5703 Image Name: Linux-2.6.17-dirty
5704 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5705 Data Size: 1029343 Bytes = 1005.2 kB
5706 Load Address: 00000000
5707 Entry Point: 00000000
5708 Verifying Checksum ... OK
5709 Uncompressing Kernel Image ... OK
5710 Booting using flat device tree at 0x300000
5711 Using MPC85xx ADS machine description
5712 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5716 More About U-Boot Image Types:
5717 ------------------------------
5719 U-Boot supports the following image types:
5721 "Standalone Programs" are directly runnable in the environment
5722 provided by U-Boot; it is expected that (if they behave
5723 well) you can continue to work in U-Boot after return from
5724 the Standalone Program.
5725 "OS Kernel Images" are usually images of some Embedded OS which
5726 will take over control completely. Usually these programs
5727 will install their own set of exception handlers, device
5728 drivers, set up the MMU, etc. - this means, that you cannot
5729 expect to re-enter U-Boot except by resetting the CPU.
5730 "RAMDisk Images" are more or less just data blocks, and their
5731 parameters (address, size) are passed to an OS kernel that is
5733 "Multi-File Images" contain several images, typically an OS
5734 (Linux) kernel image and one or more data images like
5735 RAMDisks. This construct is useful for instance when you want
5736 to boot over the network using BOOTP etc., where the boot
5737 server provides just a single image file, but you want to get
5738 for instance an OS kernel and a RAMDisk image.
5740 "Multi-File Images" start with a list of image sizes, each
5741 image size (in bytes) specified by an "uint32_t" in network
5742 byte order. This list is terminated by an "(uint32_t)0".
5743 Immediately after the terminating 0 follow the images, one by
5744 one, all aligned on "uint32_t" boundaries (size rounded up to
5745 a multiple of 4 bytes).
5747 "Firmware Images" are binary images containing firmware (like
5748 U-Boot or FPGA images) which usually will be programmed to
5751 "Script files" are command sequences that will be executed by
5752 U-Boot's command interpreter; this feature is especially
5753 useful when you configure U-Boot to use a real shell (hush)
5754 as command interpreter.
5756 Booting the Linux zImage:
5757 -------------------------
5759 On some platforms, it's possible to boot Linux zImage. This is done
5760 using the "bootz" command. The syntax of "bootz" command is the same
5761 as the syntax of "bootm" command.
5763 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5764 kernel with raw initrd images. The syntax is slightly different, the
5765 address of the initrd must be augmented by it's size, in the following
5766 format: "<initrd addres>:<initrd size>".
5772 One of the features of U-Boot is that you can dynamically load and
5773 run "standalone" applications, which can use some resources of
5774 U-Boot like console I/O functions or interrupt services.
5776 Two simple examples are included with the sources:
5781 'examples/hello_world.c' contains a small "Hello World" Demo
5782 application; it is automatically compiled when you build U-Boot.
5783 It's configured to run at address 0x00040004, so you can play with it
5787 ## Ready for S-Record download ...
5788 ~>examples/hello_world.srec
5789 1 2 3 4 5 6 7 8 9 10 11 ...
5790 [file transfer complete]
5792 ## Start Addr = 0x00040004
5794 => go 40004 Hello World! This is a test.
5795 ## Starting application at 0x00040004 ...
5806 Hit any key to exit ...
5808 ## Application terminated, rc = 0x0
5810 Another example, which demonstrates how to register a CPM interrupt
5811 handler with the U-Boot code, can be found in 'examples/timer.c'.
5812 Here, a CPM timer is set up to generate an interrupt every second.
5813 The interrupt service routine is trivial, just printing a '.'
5814 character, but this is just a demo program. The application can be
5815 controlled by the following keys:
5817 ? - print current values og the CPM Timer registers
5818 b - enable interrupts and start timer
5819 e - stop timer and disable interrupts
5820 q - quit application
5823 ## Ready for S-Record download ...
5824 ~>examples/timer.srec
5825 1 2 3 4 5 6 7 8 9 10 11 ...
5826 [file transfer complete]
5828 ## Start Addr = 0x00040004
5831 ## Starting application at 0x00040004 ...
5834 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5837 [q, b, e, ?] Set interval 1000000 us
5840 [q, b, e, ?] ........
5841 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5844 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5847 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5850 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5852 [q, b, e, ?] ...Stopping timer
5854 [q, b, e, ?] ## Application terminated, rc = 0x0
5860 Over time, many people have reported problems when trying to use the
5861 "minicom" terminal emulation program for serial download. I (wd)
5862 consider minicom to be broken, and recommend not to use it. Under
5863 Unix, I recommend to use C-Kermit for general purpose use (and
5864 especially for kermit binary protocol download ("loadb" command), and
5865 use "cu" for S-Record download ("loads" command). See
5866 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5867 for help with kermit.
5870 Nevertheless, if you absolutely want to use it try adding this
5871 configuration to your "File transfer protocols" section:
5873 Name Program Name U/D FullScr IO-Red. Multi
5874 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5875 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5881 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5882 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5884 Building requires a cross environment; it is known to work on
5885 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5886 need gmake since the Makefiles are not compatible with BSD make).
5887 Note that the cross-powerpc package does not install include files;
5888 attempting to build U-Boot will fail because <machine/ansi.h> is
5889 missing. This file has to be installed and patched manually:
5891 # cd /usr/pkg/cross/powerpc-netbsd/include
5893 # ln -s powerpc machine
5894 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5895 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5897 Native builds *don't* work due to incompatibilities between native
5898 and U-Boot include files.
5900 Booting assumes that (the first part of) the image booted is a
5901 stage-2 loader which in turn loads and then invokes the kernel
5902 proper. Loader sources will eventually appear in the NetBSD source
5903 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5904 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5907 Implementation Internals:
5908 =========================
5910 The following is not intended to be a complete description of every
5911 implementation detail. However, it should help to understand the
5912 inner workings of U-Boot and make it easier to port it to custom
5916 Initial Stack, Global Data:
5917 ---------------------------
5919 The implementation of U-Boot is complicated by the fact that U-Boot
5920 starts running out of ROM (flash memory), usually without access to
5921 system RAM (because the memory controller is not initialized yet).
5922 This means that we don't have writable Data or BSS segments, and BSS
5923 is not initialized as zero. To be able to get a C environment working
5924 at all, we have to allocate at least a minimal stack. Implementation
5925 options for this are defined and restricted by the CPU used: Some CPU
5926 models provide on-chip memory (like the IMMR area on MPC8xx and
5927 MPC826x processors), on others (parts of) the data cache can be
5928 locked as (mis-) used as memory, etc.
5930 Chris Hallinan posted a good summary of these issues to the
5931 U-Boot mailing list:
5933 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5934 From: "Chris Hallinan" <clh@net1plus.com>
5935 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5938 Correct me if I'm wrong, folks, but the way I understand it
5939 is this: Using DCACHE as initial RAM for Stack, etc, does not
5940 require any physical RAM backing up the cache. The cleverness
5941 is that the cache is being used as a temporary supply of
5942 necessary storage before the SDRAM controller is setup. It's
5943 beyond the scope of this list to explain the details, but you
5944 can see how this works by studying the cache architecture and
5945 operation in the architecture and processor-specific manuals.
5947 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5948 is another option for the system designer to use as an
5949 initial stack/RAM area prior to SDRAM being available. Either
5950 option should work for you. Using CS 4 should be fine if your
5951 board designers haven't used it for something that would
5952 cause you grief during the initial boot! It is frequently not
5955 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5956 with your processor/board/system design. The default value
5957 you will find in any recent u-boot distribution in
5958 walnut.h should work for you. I'd set it to a value larger
5959 than your SDRAM module. If you have a 64MB SDRAM module, set
5960 it above 400_0000. Just make sure your board has no resources
5961 that are supposed to respond to that address! That code in
5962 start.S has been around a while and should work as is when
5963 you get the config right.
5968 It is essential to remember this, since it has some impact on the C
5969 code for the initialization procedures:
5971 * Initialized global data (data segment) is read-only. Do not attempt
5974 * Do not use any uninitialized global data (or implicitly initialized
5975 as zero data - BSS segment) at all - this is undefined, initiali-
5976 zation is performed later (when relocating to RAM).
5978 * Stack space is very limited. Avoid big data buffers or things like
5981 Having only the stack as writable memory limits means we cannot use
5982 normal global data to share information between the code. But it
5983 turned out that the implementation of U-Boot can be greatly
5984 simplified by making a global data structure (gd_t) available to all
5985 functions. We could pass a pointer to this data as argument to _all_
5986 functions, but this would bloat the code. Instead we use a feature of
5987 the GCC compiler (Global Register Variables) to share the data: we
5988 place a pointer (gd) to the global data into a register which we
5989 reserve for this purpose.
5991 When choosing a register for such a purpose we are restricted by the
5992 relevant (E)ABI specifications for the current architecture, and by
5993 GCC's implementation.
5995 For PowerPC, the following registers have specific use:
5997 R2: reserved for system use
5998 R3-R4: parameter passing and return values
5999 R5-R10: parameter passing
6000 R13: small data area pointer
6004 (U-Boot also uses R12 as internal GOT pointer. r12
6005 is a volatile register so r12 needs to be reset when
6006 going back and forth between asm and C)
6008 ==> U-Boot will use R2 to hold a pointer to the global data
6010 Note: on PPC, we could use a static initializer (since the
6011 address of the global data structure is known at compile time),
6012 but it turned out that reserving a register results in somewhat
6013 smaller code - although the code savings are not that big (on
6014 average for all boards 752 bytes for the whole U-Boot image,
6015 624 text + 127 data).
6017 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6018 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6020 ==> U-Boot will use P3 to hold a pointer to the global data
6022 On ARM, the following registers are used:
6024 R0: function argument word/integer result
6025 R1-R3: function argument word
6026 R9: platform specific
6027 R10: stack limit (used only if stack checking is enabled)
6028 R11: argument (frame) pointer
6029 R12: temporary workspace
6032 R15: program counter
6034 ==> U-Boot will use R9 to hold a pointer to the global data
6036 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6038 On Nios II, the ABI is documented here:
6039 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6041 ==> U-Boot will use gp to hold a pointer to the global data
6043 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6044 to access small data sections, so gp is free.
6046 On NDS32, the following registers are used:
6048 R0-R1: argument/return
6050 R15: temporary register for assembler
6051 R16: trampoline register
6052 R28: frame pointer (FP)
6053 R29: global pointer (GP)
6054 R30: link register (LP)
6055 R31: stack pointer (SP)
6056 PC: program counter (PC)
6058 ==> U-Boot will use R10 to hold a pointer to the global data
6060 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6061 or current versions of GCC may "optimize" the code too much.
6066 U-Boot runs in system state and uses physical addresses, i.e. the
6067 MMU is not used either for address mapping nor for memory protection.
6069 The available memory is mapped to fixed addresses using the memory
6070 controller. In this process, a contiguous block is formed for each
6071 memory type (Flash, SDRAM, SRAM), even when it consists of several
6072 physical memory banks.
6074 U-Boot is installed in the first 128 kB of the first Flash bank (on
6075 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6076 booting and sizing and initializing DRAM, the code relocates itself
6077 to the upper end of DRAM. Immediately below the U-Boot code some
6078 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6079 configuration setting]. Below that, a structure with global Board
6080 Info data is placed, followed by the stack (growing downward).
6082 Additionally, some exception handler code is copied to the low 8 kB
6083 of DRAM (0x00000000 ... 0x00001FFF).
6085 So a typical memory configuration with 16 MB of DRAM could look like
6088 0x0000 0000 Exception Vector code
6091 0x0000 2000 Free for Application Use
6097 0x00FB FF20 Monitor Stack (Growing downward)
6098 0x00FB FFAC Board Info Data and permanent copy of global data
6099 0x00FC 0000 Malloc Arena
6102 0x00FE 0000 RAM Copy of Monitor Code
6103 ... eventually: LCD or video framebuffer
6104 ... eventually: pRAM (Protected RAM - unchanged by reset)
6105 0x00FF FFFF [End of RAM]
6108 System Initialization:
6109 ----------------------
6111 In the reset configuration, U-Boot starts at the reset entry point
6112 (on most PowerPC systems at address 0x00000100). Because of the reset
6113 configuration for CS0# this is a mirror of the on board Flash memory.
6114 To be able to re-map memory U-Boot then jumps to its link address.
6115 To be able to implement the initialization code in C, a (small!)
6116 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6117 which provide such a feature like MPC8xx or MPC8260), or in a locked
6118 part of the data cache. After that, U-Boot initializes the CPU core,
6119 the caches and the SIU.
6121 Next, all (potentially) available memory banks are mapped using a
6122 preliminary mapping. For example, we put them on 512 MB boundaries
6123 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6124 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6125 programmed for SDRAM access. Using the temporary configuration, a
6126 simple memory test is run that determines the size of the SDRAM
6129 When there is more than one SDRAM bank, and the banks are of
6130 different size, the largest is mapped first. For equal size, the first
6131 bank (CS2#) is mapped first. The first mapping is always for address
6132 0x00000000, with any additional banks following immediately to create
6133 contiguous memory starting from 0.
6135 Then, the monitor installs itself at the upper end of the SDRAM area
6136 and allocates memory for use by malloc() and for the global Board
6137 Info data; also, the exception vector code is copied to the low RAM
6138 pages, and the final stack is set up.
6140 Only after this relocation will you have a "normal" C environment;
6141 until that you are restricted in several ways, mostly because you are
6142 running from ROM, and because the code will have to be relocated to a
6146 U-Boot Porting Guide:
6147 ----------------------
6149 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6153 int main(int argc, char *argv[])
6155 sighandler_t no_more_time;
6157 signal(SIGALRM, no_more_time);
6158 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6160 if (available_money > available_manpower) {
6161 Pay consultant to port U-Boot;
6165 Download latest U-Boot source;
6167 Subscribe to u-boot mailing list;
6170 email("Hi, I am new to U-Boot, how do I get started?");
6173 Read the README file in the top level directory;
6174 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6175 Read applicable doc/*.README;
6176 Read the source, Luke;
6177 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6180 if (available_money > toLocalCurrency ($2500))
6183 Add a lot of aggravation and time;
6185 if (a similar board exists) { /* hopefully... */
6186 cp -a board/<similar> board/<myboard>
6187 cp include/configs/<similar>.h include/configs/<myboard>.h
6189 Create your own board support subdirectory;
6190 Create your own board include/configs/<myboard>.h file;
6192 Edit new board/<myboard> files
6193 Edit new include/configs/<myboard>.h
6198 Add / modify source code;
6202 email("Hi, I am having problems...");
6204 Send patch file to the U-Boot email list;
6205 if (reasonable critiques)
6206 Incorporate improvements from email list code review;
6208 Defend code as written;
6214 void no_more_time (int sig)
6223 All contributions to U-Boot should conform to the Linux kernel
6224 coding style; see the file "Documentation/CodingStyle" and the script
6225 "scripts/Lindent" in your Linux kernel source directory.
6227 Source files originating from a different project (for example the
6228 MTD subsystem) are generally exempt from these guidelines and are not
6229 reformatted to ease subsequent migration to newer versions of those
6232 Please note that U-Boot is implemented in C (and to some small parts in
6233 Assembler); no C++ is used, so please do not use C++ style comments (//)
6236 Please also stick to the following formatting rules:
6237 - remove any trailing white space
6238 - use TAB characters for indentation and vertical alignment, not spaces
6239 - make sure NOT to use DOS '\r\n' line feeds
6240 - do not add more than 2 consecutive empty lines to source files
6241 - do not add trailing empty lines to source files
6243 Submissions which do not conform to the standards may be returned
6244 with a request to reformat the changes.
6250 Since the number of patches for U-Boot is growing, we need to
6251 establish some rules. Submissions which do not conform to these rules
6252 may be rejected, even when they contain important and valuable stuff.
6254 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6256 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6257 see http://lists.denx.de/mailman/listinfo/u-boot
6259 When you send a patch, please include the following information with
6262 * For bug fixes: a description of the bug and how your patch fixes
6263 this bug. Please try to include a way of demonstrating that the
6264 patch actually fixes something.
6266 * For new features: a description of the feature and your
6269 * A CHANGELOG entry as plaintext (separate from the patch)
6271 * For major contributions, add a MAINTAINERS file with your
6272 information and associated file and directory references.
6274 * When you add support for a new board, don't forget to add a
6275 maintainer e-mail address to the boards.cfg file, too.
6277 * If your patch adds new configuration options, don't forget to
6278 document these in the README file.
6280 * The patch itself. If you are using git (which is *strongly*
6281 recommended) you can easily generate the patch using the
6282 "git format-patch". If you then use "git send-email" to send it to
6283 the U-Boot mailing list, you will avoid most of the common problems
6284 with some other mail clients.
6286 If you cannot use git, use "diff -purN OLD NEW". If your version of
6287 diff does not support these options, then get the latest version of
6290 The current directory when running this command shall be the parent
6291 directory of the U-Boot source tree (i. e. please make sure that
6292 your patch includes sufficient directory information for the
6295 We prefer patches as plain text. MIME attachments are discouraged,
6296 and compressed attachments must not be used.
6298 * If one logical set of modifications affects or creates several
6299 files, all these changes shall be submitted in a SINGLE patch file.
6301 * Changesets that contain different, unrelated modifications shall be
6302 submitted as SEPARATE patches, one patch per changeset.
6307 * Before sending the patch, run the buildman script on your patched
6308 source tree and make sure that no errors or warnings are reported
6309 for any of the boards.
6311 * Keep your modifications to the necessary minimum: A patch
6312 containing several unrelated changes or arbitrary reformats will be
6313 returned with a request to re-formatting / split it.
6315 * If you modify existing code, make sure that your new code does not
6316 add to the memory footprint of the code ;-) Small is beautiful!
6317 When adding new features, these should compile conditionally only
6318 (using #ifdef), and the resulting code with the new feature
6319 disabled must not need more memory than the old code without your
6322 * Remember that there is a size limit of 100 kB per message on the
6323 u-boot mailing list. Bigger patches will be moderated. If they are
6324 reasonable and not too big, they will be acknowledged. But patches
6325 bigger than the size limit should be avoided.