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 candidate 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_FSL_ERRATUM_A004510
381 Enables a workaround for erratum A004510. If set,
382 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
383 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
385 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
386 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
388 Defines one or two SoC revisions (low 8 bits of SVR)
389 for which the A004510 workaround should be applied.
391 The rest of SVR is either not relevant to the decision
392 of whether the erratum is present (e.g. p2040 versus
393 p2041) or is implied by the build target, which controls
394 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
396 See Freescale App Note 4493 for more information about
399 CONFIG_A003399_NOR_WORKAROUND
400 Enables a workaround for IFC erratum A003399. It is only
401 required during NOR boot.
403 CONFIG_A008044_WORKAROUND
404 Enables a workaround for T1040/T1042 erratum A008044. It is only
405 required during NAND boot and valid for Rev 1.0 SoC revision
407 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
409 This is the value to write into CCSR offset 0x18600
410 according to the A004510 workaround.
412 CONFIG_SYS_FSL_DSP_DDR_ADDR
413 This value denotes start offset of DDR memory which is
414 connected exclusively to the DSP cores.
416 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
417 This value denotes start offset of M2 memory
418 which is directly connected to the DSP core.
420 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
421 This value denotes start offset of M3 memory which is directly
422 connected to the DSP core.
424 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
425 This value denotes start offset of DSP CCSR space.
427 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
428 Single Source Clock is clocking mode present in some of FSL SoC's.
429 In this mode, a single differential clock is used to supply
430 clocks to the sysclock, ddrclock and usbclock.
432 CONFIG_SYS_CPC_REINIT_F
433 This CONFIG is defined when the CPC is configured as SRAM at the
434 time of U-Boot entry and is required to be re-initialized.
437 Indicates this SoC supports deep sleep feature. If deep sleep is
438 supported, core will start to execute uboot when wakes up.
440 - Generic CPU options:
441 CONFIG_SYS_GENERIC_GLOBAL_DATA
442 Defines global data is initialized in generic board board_init_f().
443 If this macro is defined, global data is created and cleared in
444 generic board board_init_f(). Without this macro, architecture/board
445 should initialize global data before calling board_init_f().
447 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
449 Defines the endianess of the CPU. Implementation of those
450 values is arch specific.
453 Freescale DDR driver in use. This type of DDR controller is
454 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
457 CONFIG_SYS_FSL_DDR_ADDR
458 Freescale DDR memory-mapped register base.
460 CONFIG_SYS_FSL_DDR_EMU
461 Specify emulator support for DDR. Some DDR features such as
462 deskew training are not available.
464 CONFIG_SYS_FSL_DDRC_GEN1
465 Freescale DDR1 controller.
467 CONFIG_SYS_FSL_DDRC_GEN2
468 Freescale DDR2 controller.
470 CONFIG_SYS_FSL_DDRC_GEN3
471 Freescale DDR3 controller.
473 CONFIG_SYS_FSL_DDRC_GEN4
474 Freescale DDR4 controller.
476 CONFIG_SYS_FSL_DDRC_ARM_GEN3
477 Freescale DDR3 controller for ARM-based SoCs.
480 Board config to use DDR1. It can be enabled for SoCs with
481 Freescale DDR1 or DDR2 controllers, depending on the board
485 Board config to use DDR2. It can be enabled for SoCs with
486 Freescale DDR2 or DDR3 controllers, depending on the board
490 Board config to use DDR3. It can be enabled for SoCs with
491 Freescale DDR3 or DDR3L controllers.
494 Board config to use DDR3L. It can be enabled for SoCs with
498 Board config to use DDR4. It can be enabled for SoCs with
501 CONFIG_SYS_FSL_IFC_BE
502 Defines the IFC controller register space as Big Endian
504 CONFIG_SYS_FSL_IFC_LE
505 Defines the IFC controller register space as Little Endian
507 CONFIG_SYS_FSL_IFC_CLK_DIV
508 Defines divider of platform clock(clock input to IFC controller).
510 CONFIG_SYS_FSL_LBC_CLK_DIV
511 Defines divider of platform clock(clock input to eLBC controller).
513 CONFIG_SYS_FSL_PBL_PBI
514 It enables addition of RCW (Power on reset configuration) in built image.
515 Please refer doc/README.pblimage for more details
517 CONFIG_SYS_FSL_PBL_RCW
518 It adds PBI(pre-boot instructions) commands in u-boot build image.
519 PBI commands can be used to configure SoC before it starts the execution.
520 Please refer doc/README.pblimage for more details
523 It adds a target to create boot binary having SPL binary in PBI format
524 concatenated with u-boot binary.
526 CONFIG_SYS_FSL_DDR_BE
527 Defines the DDR controller register space as Big Endian
529 CONFIG_SYS_FSL_DDR_LE
530 Defines the DDR controller register space as Little Endian
532 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
533 Physical address from the view of DDR controllers. It is the
534 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
535 it could be different for ARM SoCs.
537 CONFIG_SYS_FSL_DDR_INTLV_256B
538 DDR controller interleaving on 256-byte. This is a special
539 interleaving mode, handled by Dickens for Freescale layerscape
542 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
543 Number of controllers used as main memory.
545 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
546 Number of controllers used for other than main memory.
548 CONFIG_SYS_FSL_HAS_DP_DDR
549 Defines the SoC has DP-DDR used for DPAA.
551 CONFIG_SYS_FSL_SEC_BE
552 Defines the SEC controller register space as Big Endian
554 CONFIG_SYS_FSL_SEC_LE
555 Defines the SEC controller register space as Little Endian
558 CONFIG_SYS_INIT_SP_OFFSET
560 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
561 pointer. This is needed for the temporary stack before
564 CONFIG_SYS_MIPS_CACHE_MODE
566 Cache operation mode for the MIPS CPU.
567 See also arch/mips/include/asm/mipsregs.h.
569 CONF_CM_CACHABLE_NO_WA
572 CONF_CM_CACHABLE_NONCOHERENT
576 CONF_CM_CACHABLE_ACCELERATED
578 CONFIG_SYS_XWAY_EBU_BOOTCFG
580 Special option for Lantiq XWAY SoCs for booting from NOR flash.
581 See also arch/mips/cpu/mips32/start.S.
583 CONFIG_XWAY_SWAP_BYTES
585 Enable compilation of tools/xway-swap-bytes needed for Lantiq
586 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
587 be swapped if a flash programmer is used.
590 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
592 Select high exception vectors of the ARM core, e.g., do not
593 clear the V bit of the c1 register of CP15.
595 CONFIG_SYS_THUMB_BUILD
597 Use this flag to build U-Boot using the Thumb instruction
598 set for ARM architectures. Thumb instruction set provides
599 better code density. For ARM architectures that support
600 Thumb2 this flag will result in Thumb2 code generated by
604 Generic timer clock source frequency.
606 COUNTER_FREQUENCY_REAL
607 Generic timer clock source frequency if the real clock is
608 different from COUNTER_FREQUENCY, and can only be determined
612 CONFIG_TEGRA_SUPPORT_NON_SECURE
614 Support executing U-Boot in non-secure (NS) mode. Certain
615 impossible actions will be skipped if the CPU is in NS mode,
616 such as ARM architectural timer initialization.
618 - Linux Kernel Interface:
621 U-Boot stores all clock information in Hz
622 internally. For binary compatibility with older Linux
623 kernels (which expect the clocks passed in the
624 bd_info data to be in MHz) the environment variable
625 "clocks_in_mhz" can be defined so that U-Boot
626 converts clock data to MHZ before passing it to the
628 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
629 "clocks_in_mhz=1" is automatically included in the
632 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
634 When transferring memsize parameter to Linux, some versions
635 expect it to be in bytes, others in MB.
636 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
640 New kernel versions are expecting firmware settings to be
641 passed using flattened device trees (based on open firmware
645 * New libfdt-based support
646 * Adds the "fdt" command
647 * The bootm command automatically updates the fdt
649 OF_CPU - The proper name of the cpus node (only required for
650 MPC512X and MPC5xxx based boards).
651 OF_SOC - The proper name of the soc node (only required for
652 MPC512X and MPC5xxx based boards).
653 OF_TBCLK - The timebase frequency.
654 OF_STDOUT_PATH - The path to the console device
656 boards with QUICC Engines require OF_QE to set UCC MAC
659 CONFIG_OF_BOARD_SETUP
661 Board code has addition modification that it wants to make
662 to the flat device tree before handing it off to the kernel
664 CONFIG_OF_SYSTEM_SETUP
666 Other code has addition modification that it wants to make
667 to the flat device tree before handing it off to the kernel.
668 This causes ft_system_setup() to be called before booting
673 U-Boot can detect if an IDE device is present or not.
674 If not, and this new config option is activated, U-Boot
675 removes the ATA node from the DTS before booting Linux,
676 so the Linux IDE driver does not probe the device and
677 crash. This is needed for buggy hardware (uc101) where
678 no pull down resistor is connected to the signal IDE5V_DD7.
680 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
682 This setting is mandatory for all boards that have only one
683 machine type and must be used to specify the machine type
684 number as it appears in the ARM machine registry
685 (see http://www.arm.linux.org.uk/developer/machines/).
686 Only boards that have multiple machine types supported
687 in a single configuration file and the machine type is
688 runtime discoverable, do not have to use this setting.
690 - vxWorks boot parameters:
692 bootvx constructs a valid bootline using the following
693 environments variables: bootdev, bootfile, ipaddr, netmask,
694 serverip, gatewayip, hostname, othbootargs.
695 It loads the vxWorks image pointed bootfile.
697 Note: If a "bootargs" environment is defined, it will overwride
698 the defaults discussed just above.
700 - Cache Configuration:
701 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
702 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
703 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
705 - Cache Configuration for ARM:
706 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
708 CONFIG_SYS_PL310_BASE - Physical base address of PL310
709 controller register space
714 Define this if you want support for Amba PrimeCell PL010 UARTs.
718 Define this if you want support for Amba PrimeCell PL011 UARTs.
722 If you have Amba PrimeCell PL011 UARTs, set this variable to
723 the clock speed of the UARTs.
727 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
728 define this to a list of base addresses for each (supported)
729 port. See e.g. include/configs/versatile.h
731 CONFIG_SERIAL_HW_FLOW_CONTROL
733 Define this variable to enable hw flow control in serial driver.
734 Current user of this option is drivers/serial/nsl16550.c driver
737 Depending on board, define exactly one serial port
738 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
739 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
740 console by defining CONFIG_8xx_CONS_NONE
742 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
743 port routines must be defined elsewhere
744 (i.e. serial_init(), serial_getc(), ...)
747 CONFIG_BAUDRATE - in bps
748 Select one of the baudrates listed in
749 CONFIG_SYS_BAUDRATE_TABLE, see below.
750 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
752 - Console Rx buffer length
753 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
754 the maximum receive buffer length for the SMC.
755 This option is actual only for 82xx and 8xx possible.
756 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
757 must be defined, to setup the maximum idle timeout for
762 Only needed when CONFIG_BOOTDELAY is enabled;
763 define a command string that is automatically executed
764 when no character is read on the console interface
765 within "Boot Delay" after reset.
768 This can be used to pass arguments to the bootm
769 command. The value of CONFIG_BOOTARGS goes into the
770 environment value "bootargs".
772 CONFIG_RAMBOOT and CONFIG_NFSBOOT
773 The value of these goes into the environment as
774 "ramboot" and "nfsboot" respectively, and can be used
775 as a convenience, when switching between booting from
779 CONFIG_BOOTCOUNT_LIMIT
780 Implements a mechanism for detecting a repeating reboot
782 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
785 If no softreset save registers are found on the hardware
786 "bootcount" is stored in the environment. To prevent a
787 saveenv on all reboots, the environment variable
788 "upgrade_available" is used. If "upgrade_available" is
789 0, "bootcount" is always 0, if "upgrade_available" is
790 1 "bootcount" is incremented in the environment.
791 So the Userspace Applikation must set the "upgrade_available"
792 and "bootcount" variable to 0, if a boot was successfully.
797 When this option is #defined, the existence of the
798 environment variable "preboot" will be checked
799 immediately before starting the CONFIG_BOOTDELAY
800 countdown and/or running the auto-boot command resp.
801 entering interactive mode.
803 This feature is especially useful when "preboot" is
804 automatically generated or modified. For an example
805 see the LWMON board specific code: here "preboot" is
806 modified when the user holds down a certain
807 combination of keys on the (special) keyboard when
810 - Serial Download Echo Mode:
812 If defined to 1, all characters received during a
813 serial download (using the "loads" command) are
814 echoed back. This might be needed by some terminal
815 emulations (like "cu"), but may as well just take
816 time on others. This setting #define's the initial
817 value of the "loads_echo" environment variable.
819 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
821 Select one of the baudrates listed in
822 CONFIG_SYS_BAUDRATE_TABLE, see below.
825 Monitor commands can be included or excluded
826 from the build by using the #include files
827 <config_cmd_all.h> and #undef'ing unwanted
828 commands, or adding #define's for wanted commands.
830 The default command configuration includes all commands
831 except those marked below with a "*".
833 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
834 CONFIG_CMD_ASKENV * ask for env variable
835 CONFIG_CMD_BDI bdinfo
836 CONFIG_CMD_BEDBUG * Include BedBug Debugger
837 CONFIG_CMD_BMP * BMP support
838 CONFIG_CMD_BSP * Board specific commands
839 CONFIG_CMD_BOOTD bootd
840 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
841 CONFIG_CMD_CACHE * icache, dcache
842 CONFIG_CMD_CLK * clock command support
843 CONFIG_CMD_CONSOLE coninfo
844 CONFIG_CMD_CRC32 * crc32
845 CONFIG_CMD_DATE * support for RTC, date/time...
846 CONFIG_CMD_DHCP * DHCP support
847 CONFIG_CMD_DIAG * Diagnostics
848 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
849 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
850 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
851 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
852 CONFIG_CMD_DTT * Digital Therm and Thermostat
853 CONFIG_CMD_ECHO echo arguments
854 CONFIG_CMD_EDITENV edit env variable
855 CONFIG_CMD_EEPROM * EEPROM read/write support
856 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
857 CONFIG_CMD_ELF * bootelf, bootvx
858 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
859 CONFIG_CMD_ENV_FLAGS * display details about env flags
860 CONFIG_CMD_ENV_EXISTS * check existence of env variable
861 CONFIG_CMD_EXPORTENV * export the environment
862 CONFIG_CMD_EXT2 * ext2 command support
863 CONFIG_CMD_EXT4 * ext4 command support
864 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
865 that work for multiple fs types
866 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
867 CONFIG_CMD_SAVEENV saveenv
868 CONFIG_CMD_FDC * Floppy Disk Support
869 CONFIG_CMD_FAT * FAT command support
870 CONFIG_CMD_FLASH flinfo, erase, protect
871 CONFIG_CMD_FPGA FPGA device initialization support
872 CONFIG_CMD_FUSE * Device fuse support
873 CONFIG_CMD_GETTIME * Get time since boot
874 CONFIG_CMD_GO * the 'go' command (exec code)
875 CONFIG_CMD_GREPENV * search environment
876 CONFIG_CMD_HASH * calculate hash / digest
877 CONFIG_CMD_I2C * I2C serial bus support
878 CONFIG_CMD_IDE * IDE harddisk support
879 CONFIG_CMD_IMI iminfo
880 CONFIG_CMD_IMLS List all images found in NOR flash
881 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
882 CONFIG_CMD_IMMAP * IMMR dump support
883 CONFIG_CMD_IOTRACE * I/O tracing for debugging
884 CONFIG_CMD_IMPORTENV * import an environment
885 CONFIG_CMD_INI * import data from an ini file into the env
886 CONFIG_CMD_IRQ * irqinfo
887 CONFIG_CMD_ITEST Integer/string test of 2 values
888 CONFIG_CMD_JFFS2 * JFFS2 Support
889 CONFIG_CMD_KGDB * kgdb
890 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
891 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
893 CONFIG_CMD_LOADB loadb
894 CONFIG_CMD_LOADS loads
895 CONFIG_CMD_MD5SUM * print md5 message digest
896 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
897 CONFIG_CMD_MEMINFO * Display detailed memory information
898 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
900 CONFIG_CMD_MEMTEST * mtest
901 CONFIG_CMD_MISC Misc functions like sleep etc
902 CONFIG_CMD_MMC * MMC memory mapped support
903 CONFIG_CMD_MII * MII utility commands
904 CONFIG_CMD_MTDPARTS * MTD partition support
905 CONFIG_CMD_NAND * NAND support
906 CONFIG_CMD_NET bootp, tftpboot, rarpboot
907 CONFIG_CMD_NFS NFS support
908 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
909 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
910 CONFIG_CMD_PCI * pciinfo
911 CONFIG_CMD_PCMCIA * PCMCIA support
912 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
914 CONFIG_CMD_PORTIO * Port I/O
915 CONFIG_CMD_READ * Read raw data from partition
916 CONFIG_CMD_REGINFO * Register dump
917 CONFIG_CMD_RUN run command in env variable
918 CONFIG_CMD_SANDBOX * sb command to access sandbox features
919 CONFIG_CMD_SAVES * save S record dump
920 CONFIG_SCSI * SCSI Support
921 CONFIG_CMD_SDRAM * print SDRAM configuration information
922 (requires CONFIG_CMD_I2C)
923 CONFIG_CMD_SETGETDCR Support for DCR Register access
925 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
926 CONFIG_CMD_SHA1SUM * print sha1 memory digest
927 (requires CONFIG_CMD_MEMORY)
928 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
929 CONFIG_CMD_SOURCE "source" command Support
930 CONFIG_CMD_SPI * SPI serial bus support
931 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
932 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
933 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
934 CONFIG_CMD_TIMER * access to the system tick timer
935 CONFIG_CMD_USB * USB support
936 CONFIG_CMD_CDP * Cisco Discover Protocol support
937 CONFIG_CMD_MFSL * Microblaze FSL support
938 CONFIG_CMD_XIMG Load part of Multi Image
939 CONFIG_CMD_UUID * Generate random UUID or GUID string
941 EXAMPLE: If you want all functions except of network
942 support you can write:
944 #include "config_cmd_all.h"
945 #undef CONFIG_CMD_NET
948 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
950 Note: Don't enable the "icache" and "dcache" commands
951 (configuration option CONFIG_CMD_CACHE) unless you know
952 what you (and your U-Boot users) are doing. Data
953 cache cannot be enabled on systems like the 8xx or
954 8260 (where accesses to the IMMR region must be
955 uncached), and it cannot be disabled on all other
956 systems where we (mis-) use the data cache to hold an
957 initial stack and some data.
960 XXX - this list needs to get updated!
962 - Removal of commands
963 If no commands are needed to boot, you can disable
964 CONFIG_CMDLINE to remove them. In this case, the command line
965 will not be available, and when U-Boot wants to execute the
966 boot command (on start-up) it will call board_run_command()
967 instead. This can reduce image size significantly for very
968 simple boot procedures.
970 - Regular expression support:
972 If this variable is defined, U-Boot is linked against
973 the SLRE (Super Light Regular Expression) library,
974 which adds regex support to some commands, as for
975 example "env grep" and "setexpr".
979 If this variable is defined, U-Boot will use a device tree
980 to configure its devices, instead of relying on statically
981 compiled #defines in the board file. This option is
982 experimental and only available on a few boards. The device
983 tree is available in the global data as gd->fdt_blob.
985 U-Boot needs to get its device tree from somewhere. This can
986 be done using one of the two options below:
989 If this variable is defined, U-Boot will embed a device tree
990 binary in its image. This device tree file should be in the
991 board directory and called <soc>-<board>.dts. The binary file
992 is then picked up in board_init_f() and made available through
993 the global data structure as gd->blob.
996 If this variable is defined, U-Boot will build a device tree
997 binary. It will be called u-boot.dtb. Architecture-specific
998 code will locate it at run-time. Generally this works by:
1000 cat u-boot.bin u-boot.dtb >image.bin
1002 and in fact, U-Boot does this for you, creating a file called
1003 u-boot-dtb.bin which is useful in the common case. You can
1004 still use the individual files if you need something more
1009 If this variable is defined, it enables watchdog
1010 support for the SoC. There must be support in the SoC
1011 specific code for a watchdog. For the 8xx and 8260
1012 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1013 register. When supported for a specific SoC is
1014 available, then no further board specific code should
1015 be needed to use it.
1018 When using a watchdog circuitry external to the used
1019 SoC, then define this variable and provide board
1020 specific code for the "hw_watchdog_reset" function.
1022 CONFIG_AT91_HW_WDT_TIMEOUT
1023 specify the timeout in seconds. default 2 seconds.
1026 CONFIG_VERSION_VARIABLE
1027 If this variable is defined, an environment variable
1028 named "ver" is created by U-Boot showing the U-Boot
1029 version as printed by the "version" command.
1030 Any change to this variable will be reverted at the
1035 When CONFIG_CMD_DATE is selected, the type of the RTC
1036 has to be selected, too. Define exactly one of the
1039 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1040 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1041 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1042 CONFIG_RTC_MC146818 - use MC146818 RTC
1043 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1044 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1045 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1046 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1047 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1048 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1049 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1050 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1051 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1054 Note that if the RTC uses I2C, then the I2C interface
1055 must also be configured. See I2C Support, below.
1058 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1060 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1061 chip-ngpio pairs that tell the PCA953X driver the number of
1062 pins supported by a particular chip.
1064 Note that if the GPIO device uses I2C, then the I2C interface
1065 must also be configured. See I2C Support, below.
1068 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1069 accesses and can checksum them or write a list of them out
1070 to memory. See the 'iotrace' command for details. This is
1071 useful for testing device drivers since it can confirm that
1072 the driver behaves the same way before and after a code
1073 change. Currently this is supported on sandbox and arm. To
1074 add support for your architecture, add '#include <iotrace.h>'
1075 to the bottom of arch/<arch>/include/asm/io.h and test.
1077 Example output from the 'iotrace stats' command is below.
1078 Note that if the trace buffer is exhausted, the checksum will
1079 still continue to operate.
1082 Start: 10000000 (buffer start address)
1083 Size: 00010000 (buffer size)
1084 Offset: 00000120 (current buffer offset)
1085 Output: 10000120 (start + offset)
1086 Count: 00000018 (number of trace records)
1087 CRC32: 9526fb66 (CRC32 of all trace records)
1089 - Timestamp Support:
1091 When CONFIG_TIMESTAMP is selected, the timestamp
1092 (date and time) of an image is printed by image
1093 commands like bootm or iminfo. This option is
1094 automatically enabled when you select CONFIG_CMD_DATE .
1096 - Partition Labels (disklabels) Supported:
1097 Zero or more of the following:
1098 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1099 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1100 Intel architecture, USB sticks, etc.
1101 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1102 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1103 bootloader. Note 2TB partition limit; see
1105 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1107 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1108 CONFIG_SCSI) you must configure support for at
1109 least one non-MTD partition type as well.
1112 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1113 board configurations files but used nowhere!
1115 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1116 be performed by calling the function
1117 ide_set_reset(int reset)
1118 which has to be defined in a board specific file
1123 Set this to enable ATAPI support.
1128 Set this to enable support for disks larger than 137GB
1129 Also look at CONFIG_SYS_64BIT_LBA.
1130 Whithout these , LBA48 support uses 32bit variables and will 'only'
1131 support disks up to 2.1TB.
1133 CONFIG_SYS_64BIT_LBA:
1134 When enabled, makes the IDE subsystem use 64bit sector addresses.
1138 At the moment only there is only support for the
1139 SYM53C8XX SCSI controller; define
1140 CONFIG_SCSI_SYM53C8XX to enable it.
1142 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1143 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1144 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1145 maximum numbers of LUNs, SCSI ID's and target
1147 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1149 The environment variable 'scsidevs' is set to the number of
1150 SCSI devices found during the last scan.
1152 - NETWORK Support (PCI):
1154 Support for Intel 8254x/8257x gigabit chips.
1157 Utility code for direct access to the SPI bus on Intel 8257x.
1158 This does not do anything useful unless you set at least one
1159 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1161 CONFIG_E1000_SPI_GENERIC
1162 Allow generic access to the SPI bus on the Intel 8257x, for
1163 example with the "sspi" command.
1166 Management command for E1000 devices. When used on devices
1167 with SPI support you can reprogram the EEPROM from U-Boot.
1170 Support for Intel 82557/82559/82559ER chips.
1171 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1172 write routine for first time initialisation.
1175 Support for Digital 2114x chips.
1176 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1177 modem chip initialisation (KS8761/QS6611).
1180 Support for National dp83815 chips.
1183 Support for National dp8382[01] gigabit chips.
1185 - NETWORK Support (other):
1187 CONFIG_DRIVER_AT91EMAC
1188 Support for AT91RM9200 EMAC.
1191 Define this to use reduced MII inteface
1193 CONFIG_DRIVER_AT91EMAC_QUIET
1194 If this defined, the driver is quiet.
1195 The driver doen't show link status messages.
1197 CONFIG_CALXEDA_XGMAC
1198 Support for the Calxeda XGMAC device
1201 Support for SMSC's LAN91C96 chips.
1203 CONFIG_LAN91C96_USE_32_BIT
1204 Define this to enable 32 bit addressing
1207 Support for SMSC's LAN91C111 chip
1209 CONFIG_SMC91111_BASE
1210 Define this to hold the physical address
1211 of the device (I/O space)
1213 CONFIG_SMC_USE_32_BIT
1214 Define this if data bus is 32 bits
1216 CONFIG_SMC_USE_IOFUNCS
1217 Define this to use i/o functions instead of macros
1218 (some hardware wont work with macros)
1220 CONFIG_DRIVER_TI_EMAC
1221 Support for davinci emac
1223 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1224 Define this if you have more then 3 PHYs.
1227 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1229 CONFIG_FTGMAC100_EGIGA
1230 Define this to use GE link update with gigabit PHY.
1231 Define this if FTGMAC100 is connected to gigabit PHY.
1232 If your system has 10/100 PHY only, it might not occur
1233 wrong behavior. Because PHY usually return timeout or
1234 useless data when polling gigabit status and gigabit
1235 control registers. This behavior won't affect the
1236 correctnessof 10/100 link speed update.
1239 Support for SMSC's LAN911x and LAN921x chips
1242 Define this to hold the physical address
1243 of the device (I/O space)
1245 CONFIG_SMC911X_32_BIT
1246 Define this if data bus is 32 bits
1248 CONFIG_SMC911X_16_BIT
1249 Define this if data bus is 16 bits. If your processor
1250 automatically converts one 32 bit word to two 16 bit
1251 words you may also try CONFIG_SMC911X_32_BIT.
1254 Support for Renesas on-chip Ethernet controller
1256 CONFIG_SH_ETHER_USE_PORT
1257 Define the number of ports to be used
1259 CONFIG_SH_ETHER_PHY_ADDR
1260 Define the ETH PHY's address
1262 CONFIG_SH_ETHER_CACHE_WRITEBACK
1263 If this option is set, the driver enables cache flush.
1267 Support for PWM module on the imx6.
1271 Support TPM devices.
1273 CONFIG_TPM_TIS_INFINEON
1274 Support for Infineon i2c bus TPM devices. Only one device
1275 per system is supported at this time.
1277 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1278 Define the burst count bytes upper limit
1281 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1283 CONFIG_TPM_ST33ZP24_I2C
1284 Support for STMicroelectronics ST33ZP24 I2C devices.
1285 Requires TPM_ST33ZP24 and I2C.
1287 CONFIG_TPM_ST33ZP24_SPI
1288 Support for STMicroelectronics ST33ZP24 SPI devices.
1289 Requires TPM_ST33ZP24 and SPI.
1291 CONFIG_TPM_ATMEL_TWI
1292 Support for Atmel TWI TPM device. Requires I2C support.
1295 Support for generic parallel port TPM devices. Only one device
1296 per system is supported at this time.
1298 CONFIG_TPM_TIS_BASE_ADDRESS
1299 Base address where the generic TPM device is mapped
1300 to. Contemporary x86 systems usually map it at
1304 Add tpm monitor functions.
1305 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1306 provides monitor access to authorized functions.
1309 Define this to enable the TPM support library which provides
1310 functional interfaces to some TPM commands.
1311 Requires support for a TPM device.
1313 CONFIG_TPM_AUTH_SESSIONS
1314 Define this to enable authorized functions in the TPM library.
1315 Requires CONFIG_TPM and CONFIG_SHA1.
1318 At the moment only the UHCI host controller is
1319 supported (PIP405, MIP405, MPC5200); define
1320 CONFIG_USB_UHCI to enable it.
1321 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1322 and define CONFIG_USB_STORAGE to enable the USB
1325 Supported are USB Keyboards and USB Floppy drives
1327 MPC5200 USB requires additional defines:
1329 for 528 MHz Clock: 0x0001bbbb
1333 for differential drivers: 0x00001000
1334 for single ended drivers: 0x00005000
1335 for differential drivers on PSC3: 0x00000100
1336 for single ended drivers on PSC3: 0x00004100
1337 CONFIG_SYS_USB_EVENT_POLL
1338 May be defined to allow interrupt polling
1339 instead of using asynchronous interrupts
1341 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1342 txfilltuning field in the EHCI controller on reset.
1344 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1345 HW module registers.
1348 Define the below if you wish to use the USB console.
1349 Once firmware is rebuilt from a serial console issue the
1350 command "setenv stdin usbtty; setenv stdout usbtty" and
1351 attach your USB cable. The Unix command "dmesg" should print
1352 it has found a new device. The environment variable usbtty
1353 can be set to gserial or cdc_acm to enable your device to
1354 appear to a USB host as a Linux gserial device or a
1355 Common Device Class Abstract Control Model serial device.
1356 If you select usbtty = gserial you should be able to enumerate
1358 # modprobe usbserial vendor=0xVendorID product=0xProductID
1359 else if using cdc_acm, simply setting the environment
1360 variable usbtty to be cdc_acm should suffice. The following
1361 might be defined in YourBoardName.h
1364 Define this to build a UDC device
1367 Define this to have a tty type of device available to
1368 talk to the UDC device
1371 Define this to enable the high speed support for usb
1372 device and usbtty. If this feature is enabled, a routine
1373 int is_usbd_high_speed(void)
1374 also needs to be defined by the driver to dynamically poll
1375 whether the enumeration has succeded at high speed or full
1378 CONFIG_SYS_CONSOLE_IS_IN_ENV
1379 Define this if you want stdin, stdout &/or stderr to
1383 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1384 Derive USB clock from external clock "blah"
1385 - CONFIG_SYS_USB_EXTC_CLK 0x02
1387 If you have a USB-IF assigned VendorID then you may wish to
1388 define your own vendor specific values either in BoardName.h
1389 or directly in usbd_vendor_info.h. If you don't define
1390 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1391 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1392 should pretend to be a Linux device to it's target host.
1394 CONFIG_USBD_MANUFACTURER
1395 Define this string as the name of your company for
1396 - CONFIG_USBD_MANUFACTURER "my company"
1398 CONFIG_USBD_PRODUCT_NAME
1399 Define this string as the name of your product
1400 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1402 CONFIG_USBD_VENDORID
1403 Define this as your assigned Vendor ID from the USB
1404 Implementors Forum. This *must* be a genuine Vendor ID
1405 to avoid polluting the USB namespace.
1406 - CONFIG_USBD_VENDORID 0xFFFF
1408 CONFIG_USBD_PRODUCTID
1409 Define this as the unique Product ID
1411 - CONFIG_USBD_PRODUCTID 0xFFFF
1413 - ULPI Layer Support:
1414 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1415 the generic ULPI layer. The generic layer accesses the ULPI PHY
1416 via the platform viewport, so you need both the genric layer and
1417 the viewport enabled. Currently only Chipidea/ARC based
1418 viewport is supported.
1419 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1420 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1421 If your ULPI phy needs a different reference clock than the
1422 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1423 the appropriate value in Hz.
1426 The MMC controller on the Intel PXA is supported. To
1427 enable this define CONFIG_MMC. The MMC can be
1428 accessed from the boot prompt by mapping the device
1429 to physical memory similar to flash. Command line is
1430 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1431 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1434 Support for Renesas on-chip MMCIF controller
1436 CONFIG_SH_MMCIF_ADDR
1437 Define the base address of MMCIF registers
1440 Define the clock frequency for MMCIF
1442 CONFIG_SUPPORT_EMMC_BOOT
1443 Enable some additional features of the eMMC boot partitions.
1445 CONFIG_SUPPORT_EMMC_RPMB
1446 Enable the commands for reading, writing and programming the
1447 key for the Replay Protection Memory Block partition in eMMC.
1449 - USB Device Firmware Update (DFU) class support:
1450 CONFIG_USB_FUNCTION_DFU
1451 This enables the USB portion of the DFU USB class
1454 This enables the command "dfu" which is used to have
1455 U-Boot create a DFU class device via USB. This command
1456 requires that the "dfu_alt_info" environment variable be
1457 set and define the alt settings to expose to the host.
1460 This enables support for exposing (e)MMC devices via DFU.
1463 This enables support for exposing NAND devices via DFU.
1466 This enables support for exposing RAM via DFU.
1467 Note: DFU spec refer to non-volatile memory usage, but
1468 allow usages beyond the scope of spec - here RAM usage,
1469 one that would help mostly the developer.
1471 CONFIG_SYS_DFU_DATA_BUF_SIZE
1472 Dfu transfer uses a buffer before writing data to the
1473 raw storage device. Make the size (in bytes) of this buffer
1474 configurable. The size of this buffer is also configurable
1475 through the "dfu_bufsiz" environment variable.
1477 CONFIG_SYS_DFU_MAX_FILE_SIZE
1478 When updating files rather than the raw storage device,
1479 we use a static buffer to copy the file into and then write
1480 the buffer once we've been given the whole file. Define
1481 this to the maximum filesize (in bytes) for the buffer.
1482 Default is 4 MiB if undefined.
1484 DFU_DEFAULT_POLL_TIMEOUT
1485 Poll timeout [ms], is the timeout a device can send to the
1486 host. The host must wait for this timeout before sending
1487 a subsequent DFU_GET_STATUS request to the device.
1489 DFU_MANIFEST_POLL_TIMEOUT
1490 Poll timeout [ms], which the device sends to the host when
1491 entering dfuMANIFEST state. Host waits this timeout, before
1492 sending again an USB request to the device.
1494 - USB Device Android Fastboot support:
1495 CONFIG_USB_FUNCTION_FASTBOOT
1496 This enables the USB part of the fastboot gadget
1499 This enables the command "fastboot" which enables the Android
1500 fastboot mode for the platform's USB device. Fastboot is a USB
1501 protocol for downloading images, flashing and device control
1502 used on Android devices.
1503 See doc/README.android-fastboot for more information.
1505 CONFIG_ANDROID_BOOT_IMAGE
1506 This enables support for booting images which use the Android
1507 image format header.
1509 CONFIG_FASTBOOT_BUF_ADDR
1510 The fastboot protocol requires a large memory buffer for
1511 downloads. Define this to the starting RAM address to use for
1514 CONFIG_FASTBOOT_BUF_SIZE
1515 The fastboot protocol requires a large memory buffer for
1516 downloads. This buffer should be as large as possible for a
1517 platform. Define this to the size available RAM for fastboot.
1519 CONFIG_FASTBOOT_FLASH
1520 The fastboot protocol includes a "flash" command for writing
1521 the downloaded image to a non-volatile storage device. Define
1522 this to enable the "fastboot flash" command.
1524 CONFIG_FASTBOOT_FLASH_MMC_DEV
1525 The fastboot "flash" command requires additional information
1526 regarding the non-volatile storage device. Define this to
1527 the eMMC device that fastboot should use to store the image.
1529 CONFIG_FASTBOOT_GPT_NAME
1530 The fastboot "flash" command supports writing the downloaded
1531 image to the Protective MBR and the Primary GUID Partition
1532 Table. (Additionally, this downloaded image is post-processed
1533 to generate and write the Backup GUID Partition Table.)
1534 This occurs when the specified "partition name" on the
1535 "fastboot flash" command line matches this value.
1536 The default is "gpt" if undefined.
1538 CONFIG_FASTBOOT_MBR_NAME
1539 The fastboot "flash" command supports writing the downloaded
1541 This occurs when the "partition name" specified on the
1542 "fastboot flash" command line matches this value.
1543 If not defined the default value "mbr" is used.
1545 - Journaling Flash filesystem support:
1547 Define these for a default partition on a NAND device
1549 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1550 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1551 Define these for a default partition on a NOR device
1553 - FAT(File Allocation Table) filesystem write function support:
1556 Define this to enable support for saving memory data as a
1557 file in FAT formatted partition.
1559 This will also enable the command "fatwrite" enabling the
1560 user to write files to FAT.
1562 - CBFS (Coreboot Filesystem) support:
1565 Define this to enable support for reading from a Coreboot
1566 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1569 - FAT(File Allocation Table) filesystem cluster size:
1570 CONFIG_FS_FAT_MAX_CLUSTSIZE
1572 Define the max cluster size for fat operations else
1573 a default value of 65536 will be defined.
1576 See Kconfig help for available keyboard drivers.
1580 Define this to enable a custom keyboard support.
1581 This simply calls drv_keyboard_init() which must be
1582 defined in your board-specific files. This option is deprecated
1583 and is only used by novena. For new boards, use driver model
1588 Enable the Freescale DIU video driver. Reference boards for
1589 SOCs that have a DIU should define this macro to enable DIU
1590 support, and should also define these other macros:
1596 CONFIG_VIDEO_SW_CURSOR
1597 CONFIG_VGA_AS_SINGLE_DEVICE
1599 CONFIG_VIDEO_BMP_LOGO
1601 The DIU driver will look for the 'video-mode' environment
1602 variable, and if defined, enable the DIU as a console during
1603 boot. See the documentation file doc/README.video for a
1604 description of this variable.
1606 - LCD Support: CONFIG_LCD
1608 Define this to enable LCD support (for output to LCD
1609 display); also select one of the supported displays
1610 by defining one of these:
1614 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1616 CONFIG_NEC_NL6448AC33:
1618 NEC NL6448AC33-18. Active, color, single scan.
1620 CONFIG_NEC_NL6448BC20
1622 NEC NL6448BC20-08. 6.5", 640x480.
1623 Active, color, single scan.
1625 CONFIG_NEC_NL6448BC33_54
1627 NEC NL6448BC33-54. 10.4", 640x480.
1628 Active, color, single scan.
1632 Sharp 320x240. Active, color, single scan.
1633 It isn't 16x9, and I am not sure what it is.
1635 CONFIG_SHARP_LQ64D341
1637 Sharp LQ64D341 display, 640x480.
1638 Active, color, single scan.
1642 HLD1045 display, 640x480.
1643 Active, color, single scan.
1647 Optrex CBL50840-2 NF-FW 99 22 M5
1649 Hitachi LMG6912RPFC-00T
1653 320x240. Black & white.
1655 Normally display is black on white background; define
1656 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1658 CONFIG_LCD_ALIGNMENT
1660 Normally the LCD is page-aligned (typically 4KB). If this is
1661 defined then the LCD will be aligned to this value instead.
1662 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1663 here, since it is cheaper to change data cache settings on
1664 a per-section basis.
1669 Sometimes, for example if the display is mounted in portrait
1670 mode or even if it's mounted landscape but rotated by 180degree,
1671 we need to rotate our content of the display relative to the
1672 framebuffer, so that user can read the messages which are
1674 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1675 initialized with a given rotation from "vl_rot" out of
1676 "vidinfo_t" which is provided by the board specific code.
1677 The value for vl_rot is coded as following (matching to
1678 fbcon=rotate:<n> linux-kernel commandline):
1679 0 = no rotation respectively 0 degree
1680 1 = 90 degree rotation
1681 2 = 180 degree rotation
1682 3 = 270 degree rotation
1684 If CONFIG_LCD_ROTATION is not defined, the console will be
1685 initialized with 0degree rotation.
1689 Support drawing of RLE8-compressed bitmaps on the LCD.
1693 Enables an 'i2c edid' command which can read EDID
1694 information over I2C from an attached LCD display.
1696 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1698 If this option is set, the environment is checked for
1699 a variable "splashimage". If found, the usual display
1700 of logo, copyright and system information on the LCD
1701 is suppressed and the BMP image at the address
1702 specified in "splashimage" is loaded instead. The
1703 console is redirected to the "nulldev", too. This
1704 allows for a "silent" boot where a splash screen is
1705 loaded very quickly after power-on.
1707 CONFIG_SPLASHIMAGE_GUARD
1709 If this option is set, then U-Boot will prevent the environment
1710 variable "splashimage" from being set to a problematic address
1711 (see doc/README.displaying-bmps).
1712 This option is useful for targets where, due to alignment
1713 restrictions, an improperly aligned BMP image will cause a data
1714 abort. If you think you will not have problems with unaligned
1715 accesses (for example because your toolchain prevents them)
1716 there is no need to set this option.
1718 CONFIG_SPLASH_SCREEN_ALIGN
1720 If this option is set the splash image can be freely positioned
1721 on the screen. Environment variable "splashpos" specifies the
1722 position as "x,y". If a positive number is given it is used as
1723 number of pixel from left/top. If a negative number is given it
1724 is used as number of pixel from right/bottom. You can also
1725 specify 'm' for centering the image.
1728 setenv splashpos m,m
1729 => image at center of screen
1731 setenv splashpos 30,20
1732 => image at x = 30 and y = 20
1734 setenv splashpos -10,m
1735 => vertically centered image
1736 at x = dspWidth - bmpWidth - 9
1738 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1740 If this option is set, additionally to standard BMP
1741 images, gzipped BMP images can be displayed via the
1742 splashscreen support or the bmp command.
1744 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1746 If this option is set, 8-bit RLE compressed BMP images
1747 can be displayed via the splashscreen support or the
1750 - Compression support:
1753 Enabled by default to support gzip compressed images.
1757 If this option is set, support for bzip2 compressed
1758 images is included. If not, only uncompressed and gzip
1759 compressed images are supported.
1761 NOTE: the bzip2 algorithm requires a lot of RAM, so
1762 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1767 If this option is set, support for lzma compressed
1770 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1771 requires an amount of dynamic memory that is given by the
1774 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1776 Where lc and lp stand for, respectively, Literal context bits
1777 and Literal pos bits.
1779 This value is upper-bounded by 14MB in the worst case. Anyway,
1780 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1781 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1782 a very small buffer.
1784 Use the lzmainfo tool to determinate the lc and lp values and
1785 then calculate the amount of needed dynamic memory (ensuring
1786 the appropriate CONFIG_SYS_MALLOC_LEN value).
1790 If this option is set, support for LZO compressed images
1796 The address of PHY on MII bus.
1798 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1800 The clock frequency of the MII bus
1804 If this option is set, support for speed/duplex
1805 detection of gigabit PHY is included.
1807 CONFIG_PHY_RESET_DELAY
1809 Some PHY like Intel LXT971A need extra delay after
1810 reset before any MII register access is possible.
1811 For such PHY, set this option to the usec delay
1812 required. (minimum 300usec for LXT971A)
1814 CONFIG_PHY_CMD_DELAY (ppc4xx)
1816 Some PHY like Intel LXT971A need extra delay after
1817 command issued before MII status register can be read
1822 Define a default value for the IP address to use for
1823 the default Ethernet interface, in case this is not
1824 determined through e.g. bootp.
1825 (Environment variable "ipaddr")
1827 - Server IP address:
1830 Defines a default value for the IP address of a TFTP
1831 server to contact when using the "tftboot" command.
1832 (Environment variable "serverip")
1834 CONFIG_KEEP_SERVERADDR
1836 Keeps the server's MAC address, in the env 'serveraddr'
1837 for passing to bootargs (like Linux's netconsole option)
1839 - Gateway IP address:
1842 Defines a default value for the IP address of the
1843 default router where packets to other networks are
1845 (Environment variable "gatewayip")
1850 Defines a default value for the subnet mask (or
1851 routing prefix) which is used to determine if an IP
1852 address belongs to the local subnet or needs to be
1853 forwarded through a router.
1854 (Environment variable "netmask")
1856 - Multicast TFTP Mode:
1859 Defines whether you want to support multicast TFTP as per
1860 rfc-2090; for example to work with atftp. Lets lots of targets
1861 tftp down the same boot image concurrently. Note: the Ethernet
1862 driver in use must provide a function: mcast() to join/leave a
1865 - BOOTP Recovery Mode:
1866 CONFIG_BOOTP_RANDOM_DELAY
1868 If you have many targets in a network that try to
1869 boot using BOOTP, you may want to avoid that all
1870 systems send out BOOTP requests at precisely the same
1871 moment (which would happen for instance at recovery
1872 from a power failure, when all systems will try to
1873 boot, thus flooding the BOOTP server. Defining
1874 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1875 inserted before sending out BOOTP requests. The
1876 following delays are inserted then:
1878 1st BOOTP request: delay 0 ... 1 sec
1879 2nd BOOTP request: delay 0 ... 2 sec
1880 3rd BOOTP request: delay 0 ... 4 sec
1882 BOOTP requests: delay 0 ... 8 sec
1884 CONFIG_BOOTP_ID_CACHE_SIZE
1886 BOOTP packets are uniquely identified using a 32-bit ID. The
1887 server will copy the ID from client requests to responses and
1888 U-Boot will use this to determine if it is the destination of
1889 an incoming response. Some servers will check that addresses
1890 aren't in use before handing them out (usually using an ARP
1891 ping) and therefore take up to a few hundred milliseconds to
1892 respond. Network congestion may also influence the time it
1893 takes for a response to make it back to the client. If that
1894 time is too long, U-Boot will retransmit requests. In order
1895 to allow earlier responses to still be accepted after these
1896 retransmissions, U-Boot's BOOTP client keeps a small cache of
1897 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1898 cache. The default is to keep IDs for up to four outstanding
1899 requests. Increasing this will allow U-Boot to accept offers
1900 from a BOOTP client in networks with unusually high latency.
1902 - DHCP Advanced Options:
1903 You can fine tune the DHCP functionality by defining
1904 CONFIG_BOOTP_* symbols:
1906 CONFIG_BOOTP_SUBNETMASK
1907 CONFIG_BOOTP_GATEWAY
1908 CONFIG_BOOTP_HOSTNAME
1909 CONFIG_BOOTP_NISDOMAIN
1910 CONFIG_BOOTP_BOOTPATH
1911 CONFIG_BOOTP_BOOTFILESIZE
1914 CONFIG_BOOTP_SEND_HOSTNAME
1915 CONFIG_BOOTP_NTPSERVER
1916 CONFIG_BOOTP_TIMEOFFSET
1917 CONFIG_BOOTP_VENDOREX
1918 CONFIG_BOOTP_MAY_FAIL
1920 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1921 environment variable, not the BOOTP server.
1923 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1924 after the configured retry count, the call will fail
1925 instead of starting over. This can be used to fail over
1926 to Link-local IP address configuration if the DHCP server
1929 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1930 serverip from a DHCP server, it is possible that more
1931 than one DNS serverip is offered to the client.
1932 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1933 serverip will be stored in the additional environment
1934 variable "dnsip2". The first DNS serverip is always
1935 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1938 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1939 to do a dynamic update of a DNS server. To do this, they
1940 need the hostname of the DHCP requester.
1941 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1942 of the "hostname" environment variable is passed as
1943 option 12 to the DHCP server.
1945 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1947 A 32bit value in microseconds for a delay between
1948 receiving a "DHCP Offer" and sending the "DHCP Request".
1949 This fixes a problem with certain DHCP servers that don't
1950 respond 100% of the time to a "DHCP request". E.g. On an
1951 AT91RM9200 processor running at 180MHz, this delay needed
1952 to be *at least* 15,000 usec before a Windows Server 2003
1953 DHCP server would reply 100% of the time. I recommend at
1954 least 50,000 usec to be safe. The alternative is to hope
1955 that one of the retries will be successful but note that
1956 the DHCP timeout and retry process takes a longer than
1959 - Link-local IP address negotiation:
1960 Negotiate with other link-local clients on the local network
1961 for an address that doesn't require explicit configuration.
1962 This is especially useful if a DHCP server cannot be guaranteed
1963 to exist in all environments that the device must operate.
1965 See doc/README.link-local for more information.
1968 CONFIG_CDP_DEVICE_ID
1970 The device id used in CDP trigger frames.
1972 CONFIG_CDP_DEVICE_ID_PREFIX
1974 A two character string which is prefixed to the MAC address
1979 A printf format string which contains the ascii name of
1980 the port. Normally is set to "eth%d" which sets
1981 eth0 for the first Ethernet, eth1 for the second etc.
1983 CONFIG_CDP_CAPABILITIES
1985 A 32bit integer which indicates the device capabilities;
1986 0x00000010 for a normal host which does not forwards.
1990 An ascii string containing the version of the software.
1994 An ascii string containing the name of the platform.
1998 A 32bit integer sent on the trigger.
2000 CONFIG_CDP_POWER_CONSUMPTION
2002 A 16bit integer containing the power consumption of the
2003 device in .1 of milliwatts.
2005 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2007 A byte containing the id of the VLAN.
2009 - Status LED: CONFIG_LED_STATUS
2011 Several configurations allow to display the current
2012 status using a LED. For instance, the LED will blink
2013 fast while running U-Boot code, stop blinking as
2014 soon as a reply to a BOOTP request was received, and
2015 start blinking slow once the Linux kernel is running
2016 (supported by a status LED driver in the Linux
2017 kernel). Defining CONFIG_LED_STATUS enables this
2022 CONFIG_LED_STATUS_GPIO
2023 The status LED can be connected to a GPIO pin.
2024 In such cases, the gpio_led driver can be used as a
2025 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2026 to include the gpio_led driver in the U-Boot binary.
2028 CONFIG_GPIO_LED_INVERTED_TABLE
2029 Some GPIO connected LEDs may have inverted polarity in which
2030 case the GPIO high value corresponds to LED off state and
2031 GPIO low value corresponds to LED on state.
2032 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2033 with a list of GPIO LEDs that have inverted polarity.
2035 - CAN Support: CONFIG_CAN_DRIVER
2037 Defining CONFIG_CAN_DRIVER enables CAN driver support
2038 on those systems that support this (optional)
2039 feature, like the TQM8xxL modules.
2041 - I2C Support: CONFIG_SYS_I2C
2043 This enable the NEW i2c subsystem, and will allow you to use
2044 i2c commands at the u-boot command line (as long as you set
2045 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2046 based realtime clock chips or other i2c devices. See
2047 common/cmd_i2c.c for a description of the command line
2050 ported i2c driver to the new framework:
2051 - drivers/i2c/soft_i2c.c:
2052 - activate first bus with CONFIG_SYS_I2C_SOFT define
2053 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2054 for defining speed and slave address
2055 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2056 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2057 for defining speed and slave address
2058 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2059 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2060 for defining speed and slave address
2061 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2062 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2063 for defining speed and slave address
2065 - drivers/i2c/fsl_i2c.c:
2066 - activate i2c driver with CONFIG_SYS_I2C_FSL
2067 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2068 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2069 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2071 - If your board supports a second fsl i2c bus, define
2072 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2073 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2074 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2077 - drivers/i2c/tegra_i2c.c:
2078 - activate this driver with CONFIG_SYS_I2C_TEGRA
2079 - This driver adds 4 i2c buses with a fix speed from
2080 100000 and the slave addr 0!
2082 - drivers/i2c/ppc4xx_i2c.c
2083 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2084 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2085 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2087 - drivers/i2c/i2c_mxc.c
2088 - activate this driver with CONFIG_SYS_I2C_MXC
2089 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2090 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2091 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2092 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2093 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2094 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2095 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2096 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2097 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2098 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2099 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2100 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2101 If those defines are not set, default value is 100000
2102 for speed, and 0 for slave.
2104 - drivers/i2c/rcar_i2c.c:
2105 - activate this driver with CONFIG_SYS_I2C_RCAR
2106 - This driver adds 4 i2c buses
2108 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2109 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2110 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2111 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2112 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2113 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2114 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2115 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2116 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2118 - drivers/i2c/sh_i2c.c:
2119 - activate this driver with CONFIG_SYS_I2C_SH
2120 - This driver adds from 2 to 5 i2c buses
2122 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2123 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2124 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2125 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2126 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2127 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2128 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2129 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2130 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2131 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2132 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2134 - drivers/i2c/omap24xx_i2c.c
2135 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2136 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2137 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2138 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2139 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2140 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2141 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2142 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2143 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2144 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2145 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2147 - drivers/i2c/zynq_i2c.c
2148 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2149 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2150 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2152 - drivers/i2c/s3c24x0_i2c.c:
2153 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2154 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2155 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2156 with a fix speed from 100000 and the slave addr 0!
2158 - drivers/i2c/ihs_i2c.c
2159 - activate this driver with CONFIG_SYS_I2C_IHS
2160 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2161 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2162 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2163 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2164 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2165 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2166 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2167 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2168 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2169 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2170 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2171 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2172 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2173 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2174 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2175 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2176 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2177 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2178 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2179 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2180 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2184 CONFIG_SYS_NUM_I2C_BUSES
2185 Hold the number of i2c buses you want to use.
2187 CONFIG_SYS_I2C_DIRECT_BUS
2188 define this, if you don't use i2c muxes on your hardware.
2189 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2192 CONFIG_SYS_I2C_MAX_HOPS
2193 define how many muxes are maximal consecutively connected
2194 on one i2c bus. If you not use i2c muxes, omit this
2197 CONFIG_SYS_I2C_BUSES
2198 hold a list of buses you want to use, only used if
2199 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2200 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2201 CONFIG_SYS_NUM_I2C_BUSES = 9:
2203 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2204 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2205 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2206 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2207 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2208 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2209 {1, {I2C_NULL_HOP}}, \
2210 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2211 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2215 bus 0 on adapter 0 without a mux
2216 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2217 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2218 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2219 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2220 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2221 bus 6 on adapter 1 without a mux
2222 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2223 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2225 If you do not have i2c muxes on your board, omit this define.
2227 - Legacy I2C Support: CONFIG_HARD_I2C
2229 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2230 provides the following compelling advantages:
2232 - more than one i2c adapter is usable
2233 - approved multibus support
2234 - better i2c mux support
2236 ** Please consider updating your I2C driver now. **
2238 These enable legacy I2C serial bus commands. Defining
2239 CONFIG_HARD_I2C will include the appropriate I2C driver
2240 for the selected CPU.
2242 This will allow you to use i2c commands at the u-boot
2243 command line (as long as you set CONFIG_CMD_I2C in
2244 CONFIG_COMMANDS) and communicate with i2c based realtime
2245 clock chips. See common/cmd_i2c.c for a description of the
2246 command line interface.
2248 CONFIG_HARD_I2C selects a hardware I2C controller.
2250 There are several other quantities that must also be
2251 defined when you define CONFIG_HARD_I2C.
2253 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2254 to be the frequency (in Hz) at which you wish your i2c bus
2255 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2256 the CPU's i2c node address).
2258 Now, the u-boot i2c code for the mpc8xx
2259 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2260 and so its address should therefore be cleared to 0 (See,
2261 eg, MPC823e User's Manual p.16-473). So, set
2262 CONFIG_SYS_I2C_SLAVE to 0.
2264 CONFIG_SYS_I2C_INIT_MPC5XXX
2266 When a board is reset during an i2c bus transfer
2267 chips might think that the current transfer is still
2268 in progress. Reset the slave devices by sending start
2269 commands until the slave device responds.
2271 That's all that's required for CONFIG_HARD_I2C.
2273 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2274 then the following macros need to be defined (examples are
2275 from include/configs/lwmon.h):
2279 (Optional). Any commands necessary to enable the I2C
2280 controller or configure ports.
2282 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2286 (Only for MPC8260 CPU). The I/O port to use (the code
2287 assumes both bits are on the same port). Valid values
2288 are 0..3 for ports A..D.
2292 The code necessary to make the I2C data line active
2293 (driven). If the data line is open collector, this
2296 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2300 The code necessary to make the I2C data line tri-stated
2301 (inactive). If the data line is open collector, this
2304 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2308 Code that returns true if the I2C data line is high,
2311 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2315 If <bit> is true, sets the I2C data line high. If it
2316 is false, it clears it (low).
2318 eg: #define I2C_SDA(bit) \
2319 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2320 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2324 If <bit> is true, sets the I2C clock line high. If it
2325 is false, it clears it (low).
2327 eg: #define I2C_SCL(bit) \
2328 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2329 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2333 This delay is invoked four times per clock cycle so this
2334 controls the rate of data transfer. The data rate thus
2335 is 1 / (I2C_DELAY * 4). Often defined to be something
2338 #define I2C_DELAY udelay(2)
2340 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2342 If your arch supports the generic GPIO framework (asm/gpio.h),
2343 then you may alternatively define the two GPIOs that are to be
2344 used as SCL / SDA. Any of the previous I2C_xxx macros will
2345 have GPIO-based defaults assigned to them as appropriate.
2347 You should define these to the GPIO value as given directly to
2348 the generic GPIO functions.
2350 CONFIG_SYS_I2C_INIT_BOARD
2352 When a board is reset during an i2c bus transfer
2353 chips might think that the current transfer is still
2354 in progress. On some boards it is possible to access
2355 the i2c SCLK line directly, either by using the
2356 processor pin as a GPIO or by having a second pin
2357 connected to the bus. If this option is defined a
2358 custom i2c_init_board() routine in boards/xxx/board.c
2359 is run early in the boot sequence.
2361 CONFIG_SYS_I2C_BOARD_LATE_INIT
2363 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2364 defined a custom i2c_board_late_init() routine in
2365 boards/xxx/board.c is run AFTER the operations in i2c_init()
2366 is completed. This callpoint can be used to unreset i2c bus
2367 using CPU i2c controller register accesses for CPUs whose i2c
2368 controller provide such a method. It is called at the end of
2369 i2c_init() to allow i2c_init operations to setup the i2c bus
2370 controller on the CPU (e.g. setting bus speed & slave address).
2372 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2374 This option enables configuration of bi_iic_fast[] flags
2375 in u-boot bd_info structure based on u-boot environment
2376 variable "i2cfast". (see also i2cfast)
2378 CONFIG_I2C_MULTI_BUS
2380 This option allows the use of multiple I2C buses, each of which
2381 must have a controller. At any point in time, only one bus is
2382 active. To switch to a different bus, use the 'i2c dev' command.
2383 Note that bus numbering is zero-based.
2385 CONFIG_SYS_I2C_NOPROBES
2387 This option specifies a list of I2C devices that will be skipped
2388 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2389 is set, specify a list of bus-device pairs. Otherwise, specify
2390 a 1D array of device addresses
2393 #undef CONFIG_I2C_MULTI_BUS
2394 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2396 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2398 #define CONFIG_I2C_MULTI_BUS
2399 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2401 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2403 CONFIG_SYS_SPD_BUS_NUM
2405 If defined, then this indicates the I2C bus number for DDR SPD.
2406 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2408 CONFIG_SYS_RTC_BUS_NUM
2410 If defined, then this indicates the I2C bus number for the RTC.
2411 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2413 CONFIG_SYS_DTT_BUS_NUM
2415 If defined, then this indicates the I2C bus number for the DTT.
2416 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2418 CONFIG_SYS_I2C_DTT_ADDR:
2420 If defined, specifies the I2C address of the DTT device.
2421 If not defined, then U-Boot uses predefined value for
2422 specified DTT device.
2424 CONFIG_SOFT_I2C_READ_REPEATED_START
2426 defining this will force the i2c_read() function in
2427 the soft_i2c driver to perform an I2C repeated start
2428 between writing the address pointer and reading the
2429 data. If this define is omitted the default behaviour
2430 of doing a stop-start sequence will be used. Most I2C
2431 devices can use either method, but some require one or
2434 - SPI Support: CONFIG_SPI
2436 Enables SPI driver (so far only tested with
2437 SPI EEPROM, also an instance works with Crystal A/D and
2438 D/As on the SACSng board)
2442 Enables the driver for SPI controller on SuperH. Currently
2443 only SH7757 is supported.
2447 Enables a software (bit-bang) SPI driver rather than
2448 using hardware support. This is a general purpose
2449 driver that only requires three general I/O port pins
2450 (two outputs, one input) to function. If this is
2451 defined, the board configuration must define several
2452 SPI configuration items (port pins to use, etc). For
2453 an example, see include/configs/sacsng.h.
2457 Enables a hardware SPI driver for general-purpose reads
2458 and writes. As with CONFIG_SOFT_SPI, the board configuration
2459 must define a list of chip-select function pointers.
2460 Currently supported on some MPC8xxx processors. For an
2461 example, see include/configs/mpc8349emds.h.
2465 Enables the driver for the SPI controllers on i.MX and MXC
2466 SoCs. Currently i.MX31/35/51 are supported.
2468 CONFIG_SYS_SPI_MXC_WAIT
2469 Timeout for waiting until spi transfer completed.
2470 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2472 - FPGA Support: CONFIG_FPGA
2474 Enables FPGA subsystem.
2476 CONFIG_FPGA_<vendor>
2478 Enables support for specific chip vendors.
2481 CONFIG_FPGA_<family>
2483 Enables support for FPGA family.
2484 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2488 Specify the number of FPGA devices to support.
2490 CONFIG_CMD_FPGA_LOADMK
2492 Enable support for fpga loadmk command
2494 CONFIG_CMD_FPGA_LOADP
2496 Enable support for fpga loadp command - load partial bitstream
2498 CONFIG_CMD_FPGA_LOADBP
2500 Enable support for fpga loadbp command - load partial bitstream
2503 CONFIG_SYS_FPGA_PROG_FEEDBACK
2505 Enable printing of hash marks during FPGA configuration.
2507 CONFIG_SYS_FPGA_CHECK_BUSY
2509 Enable checks on FPGA configuration interface busy
2510 status by the configuration function. This option
2511 will require a board or device specific function to
2516 If defined, a function that provides delays in the FPGA
2517 configuration driver.
2519 CONFIG_SYS_FPGA_CHECK_CTRLC
2520 Allow Control-C to interrupt FPGA configuration
2522 CONFIG_SYS_FPGA_CHECK_ERROR
2524 Check for configuration errors during FPGA bitfile
2525 loading. For example, abort during Virtex II
2526 configuration if the INIT_B line goes low (which
2527 indicated a CRC error).
2529 CONFIG_SYS_FPGA_WAIT_INIT
2531 Maximum time to wait for the INIT_B line to de-assert
2532 after PROB_B has been de-asserted during a Virtex II
2533 FPGA configuration sequence. The default time is 500
2536 CONFIG_SYS_FPGA_WAIT_BUSY
2538 Maximum time to wait for BUSY to de-assert during
2539 Virtex II FPGA configuration. The default is 5 ms.
2541 CONFIG_SYS_FPGA_WAIT_CONFIG
2543 Time to wait after FPGA configuration. The default is
2546 - Configuration Management:
2549 Some SoCs need special image types (e.g. U-Boot binary
2550 with a special header) as build targets. By defining
2551 CONFIG_BUILD_TARGET in the SoC / board header, this
2552 special image will be automatically built upon calling
2557 If defined, this string will be added to the U-Boot
2558 version information (U_BOOT_VERSION)
2560 - Vendor Parameter Protection:
2562 U-Boot considers the values of the environment
2563 variables "serial#" (Board Serial Number) and
2564 "ethaddr" (Ethernet Address) to be parameters that
2565 are set once by the board vendor / manufacturer, and
2566 protects these variables from casual modification by
2567 the user. Once set, these variables are read-only,
2568 and write or delete attempts are rejected. You can
2569 change this behaviour:
2571 If CONFIG_ENV_OVERWRITE is #defined in your config
2572 file, the write protection for vendor parameters is
2573 completely disabled. Anybody can change or delete
2576 Alternatively, if you define _both_ an ethaddr in the
2577 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2578 Ethernet address is installed in the environment,
2579 which can be changed exactly ONCE by the user. [The
2580 serial# is unaffected by this, i. e. it remains
2583 The same can be accomplished in a more flexible way
2584 for any variable by configuring the type of access
2585 to allow for those variables in the ".flags" variable
2586 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2591 Define this variable to enable the reservation of
2592 "protected RAM", i. e. RAM which is not overwritten
2593 by U-Boot. Define CONFIG_PRAM to hold the number of
2594 kB you want to reserve for pRAM. You can overwrite
2595 this default value by defining an environment
2596 variable "pram" to the number of kB you want to
2597 reserve. Note that the board info structure will
2598 still show the full amount of RAM. If pRAM is
2599 reserved, a new environment variable "mem" will
2600 automatically be defined to hold the amount of
2601 remaining RAM in a form that can be passed as boot
2602 argument to Linux, for instance like that:
2604 setenv bootargs ... mem=\${mem}
2607 This way you can tell Linux not to use this memory,
2608 either, which results in a memory region that will
2609 not be affected by reboots.
2611 *WARNING* If your board configuration uses automatic
2612 detection of the RAM size, you must make sure that
2613 this memory test is non-destructive. So far, the
2614 following board configurations are known to be
2617 IVMS8, IVML24, SPD8xx, TQM8xxL,
2618 HERMES, IP860, RPXlite, LWMON,
2621 - Access to physical memory region (> 4GB)
2622 Some basic support is provided for operations on memory not
2623 normally accessible to U-Boot - e.g. some architectures
2624 support access to more than 4GB of memory on 32-bit
2625 machines using physical address extension or similar.
2626 Define CONFIG_PHYSMEM to access this basic support, which
2627 currently only supports clearing the memory.
2632 Define this variable to stop the system in case of a
2633 fatal error, so that you have to reset it manually.
2634 This is probably NOT a good idea for an embedded
2635 system where you want the system to reboot
2636 automatically as fast as possible, but it may be
2637 useful during development since you can try to debug
2638 the conditions that lead to the situation.
2640 CONFIG_NET_RETRY_COUNT
2642 This variable defines the number of retries for
2643 network operations like ARP, RARP, TFTP, or BOOTP
2644 before giving up the operation. If not defined, a
2645 default value of 5 is used.
2649 Timeout waiting for an ARP reply in milliseconds.
2653 Timeout in milliseconds used in NFS protocol.
2654 If you encounter "ERROR: Cannot umount" in nfs command,
2655 try longer timeout such as
2656 #define CONFIG_NFS_TIMEOUT 10000UL
2658 - Command Interpreter:
2659 CONFIG_AUTO_COMPLETE
2661 Enable auto completion of commands using TAB.
2663 CONFIG_SYS_PROMPT_HUSH_PS2
2665 This defines the secondary prompt string, which is
2666 printed when the command interpreter needs more input
2667 to complete a command. Usually "> ".
2671 In the current implementation, the local variables
2672 space and global environment variables space are
2673 separated. Local variables are those you define by
2674 simply typing `name=value'. To access a local
2675 variable later on, you have write `$name' or
2676 `${name}'; to execute the contents of a variable
2677 directly type `$name' at the command prompt.
2679 Global environment variables are those you use
2680 setenv/printenv to work with. To run a command stored
2681 in such a variable, you need to use the run command,
2682 and you must not use the '$' sign to access them.
2684 To store commands and special characters in a
2685 variable, please use double quotation marks
2686 surrounding the whole text of the variable, instead
2687 of the backslashes before semicolons and special
2690 - Command Line Editing and History:
2691 CONFIG_CMDLINE_EDITING
2693 Enable editing and History functions for interactive
2694 command line input operations
2696 - Command Line PS1/PS2 support:
2697 CONFIG_CMDLINE_PS_SUPPORT
2699 Enable support for changing the command prompt string
2700 at run-time. Only static string is supported so far.
2701 The string is obtained from environment variables PS1
2704 - Default Environment:
2705 CONFIG_EXTRA_ENV_SETTINGS
2707 Define this to contain any number of null terminated
2708 strings (variable = value pairs) that will be part of
2709 the default environment compiled into the boot image.
2711 For example, place something like this in your
2712 board's config file:
2714 #define CONFIG_EXTRA_ENV_SETTINGS \
2718 Warning: This method is based on knowledge about the
2719 internal format how the environment is stored by the
2720 U-Boot code. This is NOT an official, exported
2721 interface! Although it is unlikely that this format
2722 will change soon, there is no guarantee either.
2723 You better know what you are doing here.
2725 Note: overly (ab)use of the default environment is
2726 discouraged. Make sure to check other ways to preset
2727 the environment like the "source" command or the
2730 CONFIG_ENV_VARS_UBOOT_CONFIG
2732 Define this in order to add variables describing the
2733 U-Boot build configuration to the default environment.
2734 These will be named arch, cpu, board, vendor, and soc.
2736 Enabling this option will cause the following to be defined:
2744 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2746 Define this in order to add variables describing certain
2747 run-time determined information about the hardware to the
2748 environment. These will be named board_name, board_rev.
2750 CONFIG_DELAY_ENVIRONMENT
2752 Normally the environment is loaded when the board is
2753 initialised so that it is available to U-Boot. This inhibits
2754 that so that the environment is not available until
2755 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2756 this is instead controlled by the value of
2757 /config/load-environment.
2759 - DataFlash Support:
2760 CONFIG_HAS_DATAFLASH
2762 Defining this option enables DataFlash features and
2763 allows to read/write in Dataflash via the standard
2766 - Serial Flash support
2769 Defining this option enables SPI flash commands
2770 'sf probe/read/write/erase/update'.
2772 Usage requires an initial 'probe' to define the serial
2773 flash parameters, followed by read/write/erase/update
2776 The following defaults may be provided by the platform
2777 to handle the common case when only a single serial
2778 flash is present on the system.
2780 CONFIG_SF_DEFAULT_BUS Bus identifier
2781 CONFIG_SF_DEFAULT_CS Chip-select
2782 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2783 CONFIG_SF_DEFAULT_SPEED in Hz
2787 Define this option to include a destructive SPI flash
2790 CONFIG_SF_DUAL_FLASH Dual flash memories
2792 Define this option to use dual flash support where two flash
2793 memories can be connected with a given cs line.
2794 Currently Xilinx Zynq qspi supports these type of connections.
2796 - SystemACE Support:
2799 Adding this option adds support for Xilinx SystemACE
2800 chips attached via some sort of local bus. The address
2801 of the chip must also be defined in the
2802 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2804 #define CONFIG_SYSTEMACE
2805 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2807 When SystemACE support is added, the "ace" device type
2808 becomes available to the fat commands, i.e. fatls.
2810 - TFTP Fixed UDP Port:
2813 If this is defined, the environment variable tftpsrcp
2814 is used to supply the TFTP UDP source port value.
2815 If tftpsrcp isn't defined, the normal pseudo-random port
2816 number generator is used.
2818 Also, the environment variable tftpdstp is used to supply
2819 the TFTP UDP destination port value. If tftpdstp isn't
2820 defined, the normal port 69 is used.
2822 The purpose for tftpsrcp is to allow a TFTP server to
2823 blindly start the TFTP transfer using the pre-configured
2824 target IP address and UDP port. This has the effect of
2825 "punching through" the (Windows XP) firewall, allowing
2826 the remainder of the TFTP transfer to proceed normally.
2827 A better solution is to properly configure the firewall,
2828 but sometimes that is not allowed.
2833 This enables a generic 'hash' command which can produce
2834 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2838 Enable the hash verify command (hash -v). This adds to code
2841 CONFIG_SHA1 - This option enables support of hashing using SHA1
2842 algorithm. The hash is calculated in software.
2843 CONFIG_SHA256 - This option enables support of hashing using
2844 SHA256 algorithm. The hash is calculated in software.
2845 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2846 for SHA1/SHA256 hashing.
2847 This affects the 'hash' command and also the
2848 hash_lookup_algo() function.
2849 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2850 hardware-acceleration for SHA1/SHA256 progressive hashing.
2851 Data can be streamed in a block at a time and the hashing
2852 is performed in hardware.
2854 Note: There is also a sha1sum command, which should perhaps
2855 be deprecated in favour of 'hash sha1'.
2857 - Freescale i.MX specific commands:
2858 CONFIG_CMD_HDMIDETECT
2859 This enables 'hdmidet' command which returns true if an
2860 HDMI monitor is detected. This command is i.MX 6 specific.
2863 This enables the 'bmode' (bootmode) command for forcing
2864 a boot from specific media.
2866 This is useful for forcing the ROM's usb downloader to
2867 activate upon a watchdog reset which is nice when iterating
2868 on U-Boot. Using the reset button or running bmode normal
2869 will set it back to normal. This command currently
2870 supports i.MX53 and i.MX6.
2872 - bootcount support:
2873 CONFIG_BOOTCOUNT_LIMIT
2875 This enables the bootcounter support, see:
2876 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2879 enable special bootcounter support on at91sam9xe based boards.
2881 enable special bootcounter support on blackfin based boards.
2883 enable special bootcounter support on da850 based boards.
2884 CONFIG_BOOTCOUNT_RAM
2885 enable support for the bootcounter in RAM
2886 CONFIG_BOOTCOUNT_I2C
2887 enable support for the bootcounter on an i2c (like RTC) device.
2888 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2889 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2891 CONFIG_BOOTCOUNT_ALEN = address len
2893 - Show boot progress:
2894 CONFIG_SHOW_BOOT_PROGRESS
2896 Defining this option allows to add some board-
2897 specific code (calling a user-provided function
2898 "show_boot_progress(int)") that enables you to show
2899 the system's boot progress on some display (for
2900 example, some LED's) on your board. At the moment,
2901 the following checkpoints are implemented:
2904 Legacy uImage format:
2907 1 common/cmd_bootm.c before attempting to boot an image
2908 -1 common/cmd_bootm.c Image header has bad magic number
2909 2 common/cmd_bootm.c Image header has correct magic number
2910 -2 common/cmd_bootm.c Image header has bad checksum
2911 3 common/cmd_bootm.c Image header has correct checksum
2912 -3 common/cmd_bootm.c Image data has bad checksum
2913 4 common/cmd_bootm.c Image data has correct checksum
2914 -4 common/cmd_bootm.c Image is for unsupported architecture
2915 5 common/cmd_bootm.c Architecture check OK
2916 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2917 6 common/cmd_bootm.c Image Type check OK
2918 -6 common/cmd_bootm.c gunzip uncompression error
2919 -7 common/cmd_bootm.c Unimplemented compression type
2920 7 common/cmd_bootm.c Uncompression OK
2921 8 common/cmd_bootm.c No uncompress/copy overwrite error
2922 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2924 9 common/image.c Start initial ramdisk verification
2925 -10 common/image.c Ramdisk header has bad magic number
2926 -11 common/image.c Ramdisk header has bad checksum
2927 10 common/image.c Ramdisk header is OK
2928 -12 common/image.c Ramdisk data has bad checksum
2929 11 common/image.c Ramdisk data has correct checksum
2930 12 common/image.c Ramdisk verification complete, start loading
2931 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2932 13 common/image.c Start multifile image verification
2933 14 common/image.c No initial ramdisk, no multifile, continue.
2935 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2937 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2938 -31 post/post.c POST test failed, detected by post_output_backlog()
2939 -32 post/post.c POST test failed, detected by post_run_single()
2941 34 common/cmd_doc.c before loading a Image from a DOC device
2942 -35 common/cmd_doc.c Bad usage of "doc" command
2943 35 common/cmd_doc.c correct usage of "doc" command
2944 -36 common/cmd_doc.c No boot device
2945 36 common/cmd_doc.c correct boot device
2946 -37 common/cmd_doc.c Unknown Chip ID on boot device
2947 37 common/cmd_doc.c correct chip ID found, device available
2948 -38 common/cmd_doc.c Read Error on boot device
2949 38 common/cmd_doc.c reading Image header from DOC device OK
2950 -39 common/cmd_doc.c Image header has bad magic number
2951 39 common/cmd_doc.c Image header has correct magic number
2952 -40 common/cmd_doc.c Error reading Image from DOC device
2953 40 common/cmd_doc.c Image header has correct magic number
2954 41 common/cmd_ide.c before loading a Image from a IDE device
2955 -42 common/cmd_ide.c Bad usage of "ide" command
2956 42 common/cmd_ide.c correct usage of "ide" command
2957 -43 common/cmd_ide.c No boot device
2958 43 common/cmd_ide.c boot device found
2959 -44 common/cmd_ide.c Device not available
2960 44 common/cmd_ide.c Device available
2961 -45 common/cmd_ide.c wrong partition selected
2962 45 common/cmd_ide.c partition selected
2963 -46 common/cmd_ide.c Unknown partition table
2964 46 common/cmd_ide.c valid partition table found
2965 -47 common/cmd_ide.c Invalid partition type
2966 47 common/cmd_ide.c correct partition type
2967 -48 common/cmd_ide.c Error reading Image Header on boot device
2968 48 common/cmd_ide.c reading Image Header from IDE device OK
2969 -49 common/cmd_ide.c Image header has bad magic number
2970 49 common/cmd_ide.c Image header has correct magic number
2971 -50 common/cmd_ide.c Image header has bad checksum
2972 50 common/cmd_ide.c Image header has correct checksum
2973 -51 common/cmd_ide.c Error reading Image from IDE device
2974 51 common/cmd_ide.c reading Image from IDE device OK
2975 52 common/cmd_nand.c before loading a Image from a NAND device
2976 -53 common/cmd_nand.c Bad usage of "nand" command
2977 53 common/cmd_nand.c correct usage of "nand" command
2978 -54 common/cmd_nand.c No boot device
2979 54 common/cmd_nand.c boot device found
2980 -55 common/cmd_nand.c Unknown Chip ID on boot device
2981 55 common/cmd_nand.c correct chip ID found, device available
2982 -56 common/cmd_nand.c Error reading Image Header on boot device
2983 56 common/cmd_nand.c reading Image Header from NAND device OK
2984 -57 common/cmd_nand.c Image header has bad magic number
2985 57 common/cmd_nand.c Image header has correct magic number
2986 -58 common/cmd_nand.c Error reading Image from NAND device
2987 58 common/cmd_nand.c reading Image from NAND device OK
2989 -60 common/env_common.c Environment has a bad CRC, using default
2991 64 net/eth.c starting with Ethernet configuration.
2992 -64 net/eth.c no Ethernet found.
2993 65 net/eth.c Ethernet found.
2995 -80 common/cmd_net.c usage wrong
2996 80 common/cmd_net.c before calling net_loop()
2997 -81 common/cmd_net.c some error in net_loop() occurred
2998 81 common/cmd_net.c net_loop() back without error
2999 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3000 82 common/cmd_net.c trying automatic boot
3001 83 common/cmd_net.c running "source" command
3002 -83 common/cmd_net.c some error in automatic boot or "source" command
3003 84 common/cmd_net.c end without errors
3008 100 common/cmd_bootm.c Kernel FIT Image has correct format
3009 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3010 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3011 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3012 102 common/cmd_bootm.c Kernel unit name specified
3013 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3014 103 common/cmd_bootm.c Found configuration node
3015 104 common/cmd_bootm.c Got kernel subimage node offset
3016 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3017 105 common/cmd_bootm.c Kernel subimage hash verification OK
3018 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3019 106 common/cmd_bootm.c Architecture check OK
3020 -106 common/cmd_bootm.c Kernel subimage has wrong type
3021 107 common/cmd_bootm.c Kernel subimage type OK
3022 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3023 108 common/cmd_bootm.c Got kernel subimage data/size
3024 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3025 -109 common/cmd_bootm.c Can't get kernel subimage type
3026 -110 common/cmd_bootm.c Can't get kernel subimage comp
3027 -111 common/cmd_bootm.c Can't get kernel subimage os
3028 -112 common/cmd_bootm.c Can't get kernel subimage load address
3029 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3031 120 common/image.c Start initial ramdisk verification
3032 -120 common/image.c Ramdisk FIT image has incorrect format
3033 121 common/image.c Ramdisk FIT image has correct format
3034 122 common/image.c No ramdisk subimage unit name, using configuration
3035 -122 common/image.c Can't get configuration for ramdisk subimage
3036 123 common/image.c Ramdisk unit name specified
3037 -124 common/image.c Can't get ramdisk subimage node offset
3038 125 common/image.c Got ramdisk subimage node offset
3039 -125 common/image.c Ramdisk subimage hash verification failed
3040 126 common/image.c Ramdisk subimage hash verification OK
3041 -126 common/image.c Ramdisk subimage for unsupported architecture
3042 127 common/image.c Architecture check OK
3043 -127 common/image.c Can't get ramdisk subimage data/size
3044 128 common/image.c Got ramdisk subimage data/size
3045 129 common/image.c Can't get ramdisk load address
3046 -129 common/image.c Got ramdisk load address
3048 -130 common/cmd_doc.c Incorrect FIT image format
3049 131 common/cmd_doc.c FIT image format OK
3051 -140 common/cmd_ide.c Incorrect FIT image format
3052 141 common/cmd_ide.c FIT image format OK
3054 -150 common/cmd_nand.c Incorrect FIT image format
3055 151 common/cmd_nand.c FIT image format OK
3057 - legacy image format:
3058 CONFIG_IMAGE_FORMAT_LEGACY
3059 enables the legacy image format support in U-Boot.
3062 enabled if CONFIG_FIT_SIGNATURE is not defined.
3064 CONFIG_DISABLE_IMAGE_LEGACY
3065 disable the legacy image format
3067 This define is introduced, as the legacy image format is
3068 enabled per default for backward compatibility.
3070 - FIT image support:
3071 CONFIG_FIT_DISABLE_SHA256
3072 Supporting SHA256 hashes has quite an impact on binary size.
3073 For constrained systems sha256 hash support can be disabled
3076 TODO(sjg@chromium.org): Adjust this option to be positive,
3077 and move it to Kconfig
3079 - Standalone program support:
3080 CONFIG_STANDALONE_LOAD_ADDR
3082 This option defines a board specific value for the
3083 address where standalone program gets loaded, thus
3084 overwriting the architecture dependent default
3087 - Frame Buffer Address:
3090 Define CONFIG_FB_ADDR if you want to use specific
3091 address for frame buffer. This is typically the case
3092 when using a graphics controller has separate video
3093 memory. U-Boot will then place the frame buffer at
3094 the given address instead of dynamically reserving it
3095 in system RAM by calling lcd_setmem(), which grabs
3096 the memory for the frame buffer depending on the
3097 configured panel size.
3099 Please see board_init_f function.
3101 - Automatic software updates via TFTP server
3103 CONFIG_UPDATE_TFTP_CNT_MAX
3104 CONFIG_UPDATE_TFTP_MSEC_MAX
3106 These options enable and control the auto-update feature;
3107 for a more detailed description refer to doc/README.update.
3109 - MTD Support (mtdparts command, UBI support)
3112 Adds the MTD device infrastructure from the Linux kernel.
3113 Needed for mtdparts command support.
3115 CONFIG_MTD_PARTITIONS
3117 Adds the MTD partitioning infrastructure from the Linux
3118 kernel. Needed for UBI support.
3123 Adds commands for interacting with MTD partitions formatted
3124 with the UBI flash translation layer
3126 Requires also defining CONFIG_RBTREE
3128 CONFIG_UBI_SILENCE_MSG
3130 Make the verbose messages from UBI stop printing. This leaves
3131 warnings and errors enabled.
3134 CONFIG_MTD_UBI_WL_THRESHOLD
3135 This parameter defines the maximum difference between the highest
3136 erase counter value and the lowest erase counter value of eraseblocks
3137 of UBI devices. When this threshold is exceeded, UBI starts performing
3138 wear leveling by means of moving data from eraseblock with low erase
3139 counter to eraseblocks with high erase counter.
3141 The default value should be OK for SLC NAND flashes, NOR flashes and
3142 other flashes which have eraseblock life-cycle 100000 or more.
3143 However, in case of MLC NAND flashes which typically have eraseblock
3144 life-cycle less than 10000, the threshold should be lessened (e.g.,
3145 to 128 or 256, although it does not have to be power of 2).
3149 CONFIG_MTD_UBI_BEB_LIMIT
3150 This option specifies the maximum bad physical eraseblocks UBI
3151 expects on the MTD device (per 1024 eraseblocks). If the
3152 underlying flash does not admit of bad eraseblocks (e.g. NOR
3153 flash), this value is ignored.
3155 NAND datasheets often specify the minimum and maximum NVM
3156 (Number of Valid Blocks) for the flashes' endurance lifetime.
3157 The maximum expected bad eraseblocks per 1024 eraseblocks
3158 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3159 which gives 20 for most NANDs (MaxNVB is basically the total
3160 count of eraseblocks on the chip).
3162 To put it differently, if this value is 20, UBI will try to
3163 reserve about 1.9% of physical eraseblocks for bad blocks
3164 handling. And that will be 1.9% of eraseblocks on the entire
3165 NAND chip, not just the MTD partition UBI attaches. This means
3166 that if you have, say, a NAND flash chip admits maximum 40 bad
3167 eraseblocks, and it is split on two MTD partitions of the same
3168 size, UBI will reserve 40 eraseblocks when attaching a
3173 CONFIG_MTD_UBI_FASTMAP
3174 Fastmap is a mechanism which allows attaching an UBI device
3175 in nearly constant time. Instead of scanning the whole MTD device it
3176 only has to locate a checkpoint (called fastmap) on the device.
3177 The on-flash fastmap contains all information needed to attach
3178 the device. Using fastmap makes only sense on large devices where
3179 attaching by scanning takes long. UBI will not automatically install
3180 a fastmap on old images, but you can set the UBI parameter
3181 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3182 that fastmap-enabled images are still usable with UBI implementations
3183 without fastmap support. On typical flash devices the whole fastmap
3184 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3186 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3187 Set this parameter to enable fastmap automatically on images
3191 CONFIG_MTD_UBI_FM_DEBUG
3192 Enable UBI fastmap debug
3198 Adds commands for interacting with UBI volumes formatted as
3199 UBIFS. UBIFS is read-only in u-boot.
3201 Requires UBI support as well as CONFIG_LZO
3203 CONFIG_UBIFS_SILENCE_MSG
3205 Make the verbose messages from UBIFS stop printing. This leaves
3206 warnings and errors enabled.
3210 Enable building of SPL globally.
3213 LDSCRIPT for linking the SPL binary.
3215 CONFIG_SPL_MAX_FOOTPRINT
3216 Maximum size in memory allocated to the SPL, BSS included.
3217 When defined, the linker checks that the actual memory
3218 used by SPL from _start to __bss_end does not exceed it.
3219 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3220 must not be both defined at the same time.
3223 Maximum size of the SPL image (text, data, rodata, and
3224 linker lists sections), BSS excluded.
3225 When defined, the linker checks that the actual size does
3228 CONFIG_SPL_TEXT_BASE
3229 TEXT_BASE for linking the SPL binary.
3231 CONFIG_SPL_RELOC_TEXT_BASE
3232 Address to relocate to. If unspecified, this is equal to
3233 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3235 CONFIG_SPL_BSS_START_ADDR
3236 Link address for the BSS within the SPL binary.
3238 CONFIG_SPL_BSS_MAX_SIZE
3239 Maximum size in memory allocated to the SPL BSS.
3240 When defined, the linker checks that the actual memory used
3241 by SPL from __bss_start to __bss_end does not exceed it.
3242 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3243 must not be both defined at the same time.
3246 Adress of the start of the stack SPL will use
3248 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3249 When defined, SPL will panic() if the image it has
3250 loaded does not have a signature.
3251 Defining this is useful when code which loads images
3252 in SPL cannot guarantee that absolutely all read errors
3254 An example is the LPC32XX MLC NAND driver, which will
3255 consider that a completely unreadable NAND block is bad,
3256 and thus should be skipped silently.
3258 CONFIG_SPL_RELOC_STACK
3259 Adress of the start of the stack SPL will use after
3260 relocation. If unspecified, this is equal to
3263 CONFIG_SYS_SPL_MALLOC_START
3264 Starting address of the malloc pool used in SPL.
3265 When this option is set the full malloc is used in SPL and
3266 it is set up by spl_init() and before that, the simple malloc()
3267 can be used if CONFIG_SYS_MALLOC_F is defined.
3269 CONFIG_SYS_SPL_MALLOC_SIZE
3270 The size of the malloc pool used in SPL.
3272 CONFIG_SPL_FRAMEWORK
3273 Enable the SPL framework under common/. This framework
3274 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3275 NAND loading of the Linux Kernel.
3278 Enable booting directly to an OS from SPL.
3279 See also: doc/README.falcon
3281 CONFIG_SPL_DISPLAY_PRINT
3282 For ARM, enable an optional function to print more information
3283 about the running system.
3285 CONFIG_SPL_INIT_MINIMAL
3286 Arch init code should be built for a very small image
3288 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3289 Partition on the MMC to load U-Boot from when the MMC is being
3292 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3293 Sector to load kernel uImage from when MMC is being
3294 used in raw mode (for Falcon mode)
3296 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3297 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3298 Sector and number of sectors to load kernel argument
3299 parameters from when MMC is being used in raw mode
3302 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3303 Partition on the MMC to load U-Boot from when the MMC is being
3306 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3307 Filename to read to load U-Boot when reading from filesystem
3309 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3310 Filename to read to load kernel uImage when reading
3311 from filesystem (for Falcon mode)
3313 CONFIG_SPL_FS_LOAD_ARGS_NAME
3314 Filename to read to load kernel argument parameters
3315 when reading from filesystem (for Falcon mode)
3317 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3318 Set this for NAND SPL on PPC mpc83xx targets, so that
3319 start.S waits for the rest of the SPL to load before
3320 continuing (the hardware starts execution after just
3321 loading the first page rather than the full 4K).
3323 CONFIG_SPL_SKIP_RELOCATE
3324 Avoid SPL relocation
3326 CONFIG_SPL_NAND_BASE
3327 Include nand_base.c in the SPL. Requires
3328 CONFIG_SPL_NAND_DRIVERS.
3330 CONFIG_SPL_NAND_DRIVERS
3331 SPL uses normal NAND drivers, not minimal drivers.
3334 Include standard software ECC in the SPL
3336 CONFIG_SPL_NAND_SIMPLE
3337 Support for NAND boot using simple NAND drivers that
3338 expose the cmd_ctrl() interface.
3341 Support for a lightweight UBI (fastmap) scanner and
3344 CONFIG_SPL_NAND_RAW_ONLY
3345 Support to boot only raw u-boot.bin images. Use this only
3346 if you need to save space.
3348 CONFIG_SPL_COMMON_INIT_DDR
3349 Set for common ddr init with serial presence detect in
3352 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3353 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3354 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3355 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3356 CONFIG_SYS_NAND_ECCBYTES
3357 Defines the size and behavior of the NAND that SPL uses
3360 CONFIG_SPL_NAND_BOOT
3361 Add support NAND boot
3363 CONFIG_SYS_NAND_U_BOOT_OFFS
3364 Location in NAND to read U-Boot from
3366 CONFIG_SYS_NAND_U_BOOT_DST
3367 Location in memory to load U-Boot to
3369 CONFIG_SYS_NAND_U_BOOT_SIZE
3370 Size of image to load
3372 CONFIG_SYS_NAND_U_BOOT_START
3373 Entry point in loaded image to jump to
3375 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3376 Define this if you need to first read the OOB and then the
3377 data. This is used, for example, on davinci platforms.
3379 CONFIG_SPL_OMAP3_ID_NAND
3380 Support for an OMAP3-specific set of functions to return the
3381 ID and MFR of the first attached NAND chip, if present.
3383 CONFIG_SPL_RAM_DEVICE
3384 Support for running image already present in ram, in SPL binary
3387 Image offset to which the SPL should be padded before appending
3388 the SPL payload. By default, this is defined as
3389 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3390 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3391 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3394 Final target image containing SPL and payload. Some SPLs
3395 use an arch-specific makefile fragment instead, for
3396 example if more than one image needs to be produced.
3398 CONFIG_FIT_SPL_PRINT
3399 Printing information about a FIT image adds quite a bit of
3400 code to SPL. So this is normally disabled in SPL. Use this
3401 option to re-enable it. This will affect the output of the
3402 bootm command when booting a FIT image.
3406 Enable building of TPL globally.
3409 Image offset to which the TPL should be padded before appending
3410 the TPL payload. By default, this is defined as
3411 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3412 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3413 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3415 - Interrupt support (PPC):
3417 There are common interrupt_init() and timer_interrupt()
3418 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3419 for CPU specific initialization. interrupt_init_cpu()
3420 should set decrementer_count to appropriate value. If
3421 CPU resets decrementer automatically after interrupt
3422 (ppc4xx) it should set decrementer_count to zero.
3423 timer_interrupt() calls timer_interrupt_cpu() for CPU
3424 specific handling. If board has watchdog / status_led
3425 / other_activity_monitor it works automatically from
3426 general timer_interrupt().
3429 Board initialization settings:
3430 ------------------------------
3432 During Initialization u-boot calls a number of board specific functions
3433 to allow the preparation of board specific prerequisites, e.g. pin setup
3434 before drivers are initialized. To enable these callbacks the
3435 following configuration macros have to be defined. Currently this is
3436 architecture specific, so please check arch/your_architecture/lib/board.c
3437 typically in board_init_f() and board_init_r().
3439 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3440 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3441 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3442 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3444 Configuration Settings:
3445 -----------------------
3447 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3448 Optionally it can be defined to support 64-bit memory commands.
3450 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3451 undefine this when you're short of memory.
3453 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3454 width of the commands listed in the 'help' command output.
3456 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3457 prompt for user input.
3459 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3461 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3463 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3465 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3466 the application (usually a Linux kernel) when it is
3469 - CONFIG_SYS_BAUDRATE_TABLE:
3470 List of legal baudrate settings for this board.
3472 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3473 Begin and End addresses of the area used by the
3476 - CONFIG_SYS_ALT_MEMTEST:
3477 Enable an alternate, more extensive memory test.
3479 - CONFIG_SYS_MEMTEST_SCRATCH:
3480 Scratch address used by the alternate memory test
3481 You only need to set this if address zero isn't writeable
3483 - CONFIG_SYS_MEM_RESERVE_SECURE
3484 Only implemented for ARMv8 for now.
3485 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3486 is substracted from total RAM and won't be reported to OS.
3487 This memory can be used as secure memory. A variable
3488 gd->arch.secure_ram is used to track the location. In systems
3489 the RAM base is not zero, or RAM is divided into banks,
3490 this variable needs to be recalcuated to get the address.
3492 - CONFIG_SYS_MEM_TOP_HIDE:
3493 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3494 this specified memory area will get subtracted from the top
3495 (end) of RAM and won't get "touched" at all by U-Boot. By
3496 fixing up gd->ram_size the Linux kernel should gets passed
3497 the now "corrected" memory size and won't touch it either.
3498 This should work for arch/ppc and arch/powerpc. Only Linux
3499 board ports in arch/powerpc with bootwrapper support that
3500 recalculate the memory size from the SDRAM controller setup
3501 will have to get fixed in Linux additionally.
3503 This option can be used as a workaround for the 440EPx/GRx
3504 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3507 WARNING: Please make sure that this value is a multiple of
3508 the Linux page size (normally 4k). If this is not the case,
3509 then the end address of the Linux memory will be located at a
3510 non page size aligned address and this could cause major
3513 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3514 Enable temporary baudrate change while serial download
3516 - CONFIG_SYS_SDRAM_BASE:
3517 Physical start address of SDRAM. _Must_ be 0 here.
3519 - CONFIG_SYS_FLASH_BASE:
3520 Physical start address of Flash memory.
3522 - CONFIG_SYS_MONITOR_BASE:
3523 Physical start address of boot monitor code (set by
3524 make config files to be same as the text base address
3525 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3526 CONFIG_SYS_FLASH_BASE when booting from flash.
3528 - CONFIG_SYS_MONITOR_LEN:
3529 Size of memory reserved for monitor code, used to
3530 determine _at_compile_time_ (!) if the environment is
3531 embedded within the U-Boot image, or in a separate
3534 - CONFIG_SYS_MALLOC_LEN:
3535 Size of DRAM reserved for malloc() use.
3537 - CONFIG_SYS_MALLOC_F_LEN
3538 Size of the malloc() pool for use before relocation. If
3539 this is defined, then a very simple malloc() implementation
3540 will become available before relocation. The address is just
3541 below the global data, and the stack is moved down to make
3544 This feature allocates regions with increasing addresses
3545 within the region. calloc() is supported, but realloc()
3546 is not available. free() is supported but does nothing.
3547 The memory will be freed (or in fact just forgotten) when
3548 U-Boot relocates itself.
3550 - CONFIG_SYS_MALLOC_SIMPLE
3551 Provides a simple and small malloc() and calloc() for those
3552 boards which do not use the full malloc in SPL (which is
3553 enabled with CONFIG_SYS_SPL_MALLOC_START).
3555 - CONFIG_SYS_NONCACHED_MEMORY:
3556 Size of non-cached memory area. This area of memory will be
3557 typically located right below the malloc() area and mapped
3558 uncached in the MMU. This is useful for drivers that would
3559 otherwise require a lot of explicit cache maintenance. For
3560 some drivers it's also impossible to properly maintain the
3561 cache. For example if the regions that need to be flushed
3562 are not a multiple of the cache-line size, *and* padding
3563 cannot be allocated between the regions to align them (i.e.
3564 if the HW requires a contiguous array of regions, and the
3565 size of each region is not cache-aligned), then a flush of
3566 one region may result in overwriting data that hardware has
3567 written to another region in the same cache-line. This can
3568 happen for example in network drivers where descriptors for
3569 buffers are typically smaller than the CPU cache-line (e.g.
3570 16 bytes vs. 32 or 64 bytes).
3572 Non-cached memory is only supported on 32-bit ARM at present.
3574 - CONFIG_SYS_BOOTM_LEN:
3575 Normally compressed uImages are limited to an
3576 uncompressed size of 8 MBytes. If this is not enough,
3577 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3578 to adjust this setting to your needs.
3580 - CONFIG_SYS_BOOTMAPSZ:
3581 Maximum size of memory mapped by the startup code of
3582 the Linux kernel; all data that must be processed by
3583 the Linux kernel (bd_info, boot arguments, FDT blob if
3584 used) must be put below this limit, unless "bootm_low"
3585 environment variable is defined and non-zero. In such case
3586 all data for the Linux kernel must be between "bootm_low"
3587 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3588 variable "bootm_mapsize" will override the value of
3589 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3590 then the value in "bootm_size" will be used instead.
3592 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3593 Enable initrd_high functionality. If defined then the
3594 initrd_high feature is enabled and the bootm ramdisk subcommand
3597 - CONFIG_SYS_BOOT_GET_CMDLINE:
3598 Enables allocating and saving kernel cmdline in space between
3599 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3601 - CONFIG_SYS_BOOT_GET_KBD:
3602 Enables allocating and saving a kernel copy of the bd_info in
3603 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3605 - CONFIG_SYS_MAX_FLASH_BANKS:
3606 Max number of Flash memory banks
3608 - CONFIG_SYS_MAX_FLASH_SECT:
3609 Max number of sectors on a Flash chip
3611 - CONFIG_SYS_FLASH_ERASE_TOUT:
3612 Timeout for Flash erase operations (in ms)
3614 - CONFIG_SYS_FLASH_WRITE_TOUT:
3615 Timeout for Flash write operations (in ms)
3617 - CONFIG_SYS_FLASH_LOCK_TOUT
3618 Timeout for Flash set sector lock bit operation (in ms)
3620 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3621 Timeout for Flash clear lock bits operation (in ms)
3623 - CONFIG_SYS_FLASH_PROTECTION
3624 If defined, hardware flash sectors protection is used
3625 instead of U-Boot software protection.
3627 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3629 Enable TFTP transfers directly to flash memory;
3630 without this option such a download has to be
3631 performed in two steps: (1) download to RAM, and (2)
3632 copy from RAM to flash.
3634 The two-step approach is usually more reliable, since
3635 you can check if the download worked before you erase
3636 the flash, but in some situations (when system RAM is
3637 too limited to allow for a temporary copy of the
3638 downloaded image) this option may be very useful.
3640 - CONFIG_SYS_FLASH_CFI:
3641 Define if the flash driver uses extra elements in the
3642 common flash structure for storing flash geometry.
3644 - CONFIG_FLASH_CFI_DRIVER
3645 This option also enables the building of the cfi_flash driver
3646 in the drivers directory
3648 - CONFIG_FLASH_CFI_MTD
3649 This option enables the building of the cfi_mtd driver
3650 in the drivers directory. The driver exports CFI flash
3653 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3654 Use buffered writes to flash.
3656 - CONFIG_FLASH_SPANSION_S29WS_N
3657 s29ws-n MirrorBit flash has non-standard addresses for buffered
3660 - CONFIG_SYS_FLASH_QUIET_TEST
3661 If this option is defined, the common CFI flash doesn't
3662 print it's warning upon not recognized FLASH banks. This
3663 is useful, if some of the configured banks are only
3664 optionally available.
3666 - CONFIG_FLASH_SHOW_PROGRESS
3667 If defined (must be an integer), print out countdown
3668 digits and dots. Recommended value: 45 (9..1) for 80
3669 column displays, 15 (3..1) for 40 column displays.
3671 - CONFIG_FLASH_VERIFY
3672 If defined, the content of the flash (destination) is compared
3673 against the source after the write operation. An error message
3674 will be printed when the contents are not identical.
3675 Please note that this option is useless in nearly all cases,
3676 since such flash programming errors usually are detected earlier
3677 while unprotecting/erasing/programming. Please only enable
3678 this option if you really know what you are doing.
3680 - CONFIG_SYS_RX_ETH_BUFFER:
3681 Defines the number of Ethernet receive buffers. On some
3682 Ethernet controllers it is recommended to set this value
3683 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3684 buffers can be full shortly after enabling the interface
3685 on high Ethernet traffic.
3686 Defaults to 4 if not defined.
3688 - CONFIG_ENV_MAX_ENTRIES
3690 Maximum number of entries in the hash table that is used
3691 internally to store the environment settings. The default
3692 setting is supposed to be generous and should work in most
3693 cases. This setting can be used to tune behaviour; see
3694 lib/hashtable.c for details.
3696 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3697 - CONFIG_ENV_FLAGS_LIST_STATIC
3698 Enable validation of the values given to environment variables when
3699 calling env set. Variables can be restricted to only decimal,
3700 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3701 the variables can also be restricted to IP address or MAC address.
3703 The format of the list is:
3704 type_attribute = [s|d|x|b|i|m]
3705 access_attribute = [a|r|o|c]
3706 attributes = type_attribute[access_attribute]
3707 entry = variable_name[:attributes]
3710 The type attributes are:
3711 s - String (default)
3714 b - Boolean ([1yYtT|0nNfF])
3718 The access attributes are:
3724 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3725 Define this to a list (string) to define the ".flags"
3726 environment variable in the default or embedded environment.
3728 - CONFIG_ENV_FLAGS_LIST_STATIC
3729 Define this to a list (string) to define validation that
3730 should be done if an entry is not found in the ".flags"
3731 environment variable. To override a setting in the static
3732 list, simply add an entry for the same variable name to the
3735 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3736 regular expression. This allows multiple variables to define the same
3737 flags without explicitly listing them for each variable.
3739 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3740 If defined, don't allow the -f switch to env set override variable
3743 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3744 This is set by OMAP boards for the max time that reset should
3745 be asserted. See doc/README.omap-reset-time for details on how
3746 the value can be calculated on a given board.
3749 If stdint.h is available with your toolchain you can define this
3750 option to enable it. You can provide option 'USE_STDINT=1' when
3751 building U-Boot to enable this.
3753 The following definitions that deal with the placement and management
3754 of environment data (variable area); in general, we support the
3755 following configurations:
3757 - CONFIG_BUILD_ENVCRC:
3759 Builds up envcrc with the target environment so that external utils
3760 may easily extract it and embed it in final U-Boot images.
3762 - CONFIG_ENV_IS_IN_FLASH:
3764 Define this if the environment is in flash memory.
3766 a) The environment occupies one whole flash sector, which is
3767 "embedded" in the text segment with the U-Boot code. This
3768 happens usually with "bottom boot sector" or "top boot
3769 sector" type flash chips, which have several smaller
3770 sectors at the start or the end. For instance, such a
3771 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3772 such a case you would place the environment in one of the
3773 4 kB sectors - with U-Boot code before and after it. With
3774 "top boot sector" type flash chips, you would put the
3775 environment in one of the last sectors, leaving a gap
3776 between U-Boot and the environment.
3778 - CONFIG_ENV_OFFSET:
3780 Offset of environment data (variable area) to the
3781 beginning of flash memory; for instance, with bottom boot
3782 type flash chips the second sector can be used: the offset
3783 for this sector is given here.
3785 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3789 This is just another way to specify the start address of
3790 the flash sector containing the environment (instead of
3793 - CONFIG_ENV_SECT_SIZE:
3795 Size of the sector containing the environment.
3798 b) Sometimes flash chips have few, equal sized, BIG sectors.
3799 In such a case you don't want to spend a whole sector for
3804 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3805 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3806 of this flash sector for the environment. This saves
3807 memory for the RAM copy of the environment.
3809 It may also save flash memory if you decide to use this
3810 when your environment is "embedded" within U-Boot code,
3811 since then the remainder of the flash sector could be used
3812 for U-Boot code. It should be pointed out that this is
3813 STRONGLY DISCOURAGED from a robustness point of view:
3814 updating the environment in flash makes it always
3815 necessary to erase the WHOLE sector. If something goes
3816 wrong before the contents has been restored from a copy in
3817 RAM, your target system will be dead.
3819 - CONFIG_ENV_ADDR_REDUND
3820 CONFIG_ENV_SIZE_REDUND
3822 These settings describe a second storage area used to hold
3823 a redundant copy of the environment data, so that there is
3824 a valid backup copy in case there is a power failure during
3825 a "saveenv" operation.
3827 BE CAREFUL! Any changes to the flash layout, and some changes to the
3828 source code will make it necessary to adapt <board>/u-boot.lds*
3832 - CONFIG_ENV_IS_IN_NVRAM:
3834 Define this if you have some non-volatile memory device
3835 (NVRAM, battery buffered SRAM) which you want to use for the
3841 These two #defines are used to determine the memory area you
3842 want to use for environment. It is assumed that this memory
3843 can just be read and written to, without any special
3846 BE CAREFUL! The first access to the environment happens quite early
3847 in U-Boot initialization (when we try to get the setting of for the
3848 console baudrate). You *MUST* have mapped your NVRAM area then, or
3851 Please note that even with NVRAM we still use a copy of the
3852 environment in RAM: we could work on NVRAM directly, but we want to
3853 keep settings there always unmodified except somebody uses "saveenv"
3854 to save the current settings.
3857 - CONFIG_ENV_IS_IN_EEPROM:
3859 Use this if you have an EEPROM or similar serial access
3860 device and a driver for it.
3862 - CONFIG_ENV_OFFSET:
3865 These two #defines specify the offset and size of the
3866 environment area within the total memory of your EEPROM.
3868 - CONFIG_SYS_I2C_EEPROM_ADDR:
3869 If defined, specified the chip address of the EEPROM device.
3870 The default address is zero.
3872 - CONFIG_SYS_I2C_EEPROM_BUS:
3873 If defined, specified the i2c bus of the EEPROM device.
3875 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3876 If defined, the number of bits used to address bytes in a
3877 single page in the EEPROM device. A 64 byte page, for example
3878 would require six bits.
3880 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3881 If defined, the number of milliseconds to delay between
3882 page writes. The default is zero milliseconds.
3884 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3885 The length in bytes of the EEPROM memory array address. Note
3886 that this is NOT the chip address length!
3888 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3889 EEPROM chips that implement "address overflow" are ones
3890 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3891 address and the extra bits end up in the "chip address" bit
3892 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3895 Note that we consider the length of the address field to
3896 still be one byte because the extra address bits are hidden
3897 in the chip address.
3899 - CONFIG_SYS_EEPROM_SIZE:
3900 The size in bytes of the EEPROM device.
3902 - CONFIG_ENV_EEPROM_IS_ON_I2C
3903 define this, if you have I2C and SPI activated, and your
3904 EEPROM, which holds the environment, is on the I2C bus.
3906 - CONFIG_I2C_ENV_EEPROM_BUS
3907 if you have an Environment on an EEPROM reached over
3908 I2C muxes, you can define here, how to reach this
3909 EEPROM. For example:
3911 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3913 EEPROM which holds the environment, is reached over
3914 a pca9547 i2c mux with address 0x70, channel 3.
3916 - CONFIG_ENV_IS_IN_DATAFLASH:
3918 Define this if you have a DataFlash memory device which you
3919 want to use for the environment.
3921 - CONFIG_ENV_OFFSET:
3925 These three #defines specify the offset and size of the
3926 environment area within the total memory of your DataFlash placed
3927 at the specified address.
3929 - CONFIG_ENV_IS_IN_SPI_FLASH:
3931 Define this if you have a SPI Flash memory device which you
3932 want to use for the environment.
3934 - CONFIG_ENV_OFFSET:
3937 These two #defines specify the offset and size of the
3938 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3939 aligned to an erase sector boundary.
3941 - CONFIG_ENV_SECT_SIZE:
3943 Define the SPI flash's sector size.
3945 - CONFIG_ENV_OFFSET_REDUND (optional):
3947 This setting describes a second storage area of CONFIG_ENV_SIZE
3948 size used to hold a redundant copy of the environment data, so
3949 that there is a valid backup copy in case there is a power failure
3950 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3951 aligned to an erase sector boundary.
3953 - CONFIG_ENV_SPI_BUS (optional):
3954 - CONFIG_ENV_SPI_CS (optional):
3956 Define the SPI bus and chip select. If not defined they will be 0.
3958 - CONFIG_ENV_SPI_MAX_HZ (optional):
3960 Define the SPI max work clock. If not defined then use 1MHz.
3962 - CONFIG_ENV_SPI_MODE (optional):
3964 Define the SPI work mode. If not defined then use SPI_MODE_3.
3966 - CONFIG_ENV_IS_IN_REMOTE:
3968 Define this if you have a remote memory space which you
3969 want to use for the local device's environment.
3974 These two #defines specify the address and size of the
3975 environment area within the remote memory space. The
3976 local device can get the environment from remote memory
3977 space by SRIO or PCIE links.
3979 BE CAREFUL! For some special cases, the local device can not use
3980 "saveenv" command. For example, the local device will get the
3981 environment stored in a remote NOR flash by SRIO or PCIE link,
3982 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3984 - CONFIG_ENV_IS_IN_NAND:
3986 Define this if you have a NAND device which you want to use
3987 for the environment.
3989 - CONFIG_ENV_OFFSET:
3992 These two #defines specify the offset and size of the environment
3993 area within the first NAND device. CONFIG_ENV_OFFSET must be
3994 aligned to an erase block boundary.
3996 - CONFIG_ENV_OFFSET_REDUND (optional):
3998 This setting describes a second storage area of CONFIG_ENV_SIZE
3999 size used to hold a redundant copy of the environment data, so
4000 that there is a valid backup copy in case there is a power failure
4001 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
4002 aligned to an erase block boundary.
4004 - CONFIG_ENV_RANGE (optional):
4006 Specifies the length of the region in which the environment
4007 can be written. This should be a multiple of the NAND device's
4008 block size. Specifying a range with more erase blocks than
4009 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4010 the range to be avoided.
4012 - CONFIG_ENV_OFFSET_OOB (optional):
4014 Enables support for dynamically retrieving the offset of the
4015 environment from block zero's out-of-band data. The
4016 "nand env.oob" command can be used to record this offset.
4017 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4018 using CONFIG_ENV_OFFSET_OOB.
4020 - CONFIG_NAND_ENV_DST
4022 Defines address in RAM to which the nand_spl code should copy the
4023 environment. If redundant environment is used, it will be copied to
4024 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4026 - CONFIG_ENV_IS_IN_UBI:
4028 Define this if you have an UBI volume that you want to use for the
4029 environment. This has the benefit of wear-leveling the environment
4030 accesses, which is important on NAND.
4032 - CONFIG_ENV_UBI_PART:
4034 Define this to a string that is the mtd partition containing the UBI.
4036 - CONFIG_ENV_UBI_VOLUME:
4038 Define this to the name of the volume that you want to store the
4041 - CONFIG_ENV_UBI_VOLUME_REDUND:
4043 Define this to the name of another volume to store a second copy of
4044 the environment in. This will enable redundant environments in UBI.
4045 It is assumed that both volumes are in the same MTD partition.
4047 - CONFIG_UBI_SILENCE_MSG
4048 - CONFIG_UBIFS_SILENCE_MSG
4050 You will probably want to define these to avoid a really noisy system
4051 when storing the env in UBI.
4053 - CONFIG_ENV_IS_IN_FAT:
4054 Define this if you want to use the FAT file system for the environment.
4056 - FAT_ENV_INTERFACE:
4058 Define this to a string that is the name of the block device.
4060 - FAT_ENV_DEVICE_AND_PART:
4062 Define this to a string to specify the partition of the device. It can
4065 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4066 - "D:P": device D partition P. Error occurs if device D has no
4069 - "D" or "D:": device D partition 1 if device D has partition
4070 table, or the whole device D if has no partition
4072 - "D:auto": first partition in device D with bootable flag set.
4073 If none, first valid partition in device D. If no
4074 partition table then means device D.
4078 It's a string of the FAT file name. This file use to store the
4082 This should be defined. Otherwise it cannot save the environment file.
4084 - CONFIG_ENV_IS_IN_MMC:
4086 Define this if you have an MMC device which you want to use for the
4089 - CONFIG_SYS_MMC_ENV_DEV:
4091 Specifies which MMC device the environment is stored in.
4093 - CONFIG_SYS_MMC_ENV_PART (optional):
4095 Specifies which MMC partition the environment is stored in. If not
4096 set, defaults to partition 0, the user area. Common values might be
4097 1 (first MMC boot partition), 2 (second MMC boot partition).
4099 - CONFIG_ENV_OFFSET:
4102 These two #defines specify the offset and size of the environment
4103 area within the specified MMC device.
4105 If offset is positive (the usual case), it is treated as relative to
4106 the start of the MMC partition. If offset is negative, it is treated
4107 as relative to the end of the MMC partition. This can be useful if
4108 your board may be fitted with different MMC devices, which have
4109 different sizes for the MMC partitions, and you always want the
4110 environment placed at the very end of the partition, to leave the
4111 maximum possible space before it, to store other data.
4113 These two values are in units of bytes, but must be aligned to an
4114 MMC sector boundary.
4116 - CONFIG_ENV_OFFSET_REDUND (optional):
4118 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4119 hold a redundant copy of the environment data. This provides a
4120 valid backup copy in case the other copy is corrupted, e.g. due
4121 to a power failure during a "saveenv" operation.
4123 This value may also be positive or negative; this is handled in the
4124 same way as CONFIG_ENV_OFFSET.
4126 This value is also in units of bytes, but must also be aligned to
4127 an MMC sector boundary.
4129 - CONFIG_ENV_SIZE_REDUND (optional):
4131 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4132 set. If this value is set, it must be set to the same value as
4135 - CONFIG_SYS_SPI_INIT_OFFSET
4137 Defines offset to the initial SPI buffer area in DPRAM. The
4138 area is used at an early stage (ROM part) if the environment
4139 is configured to reside in the SPI EEPROM: We need a 520 byte
4140 scratch DPRAM area. It is used between the two initialization
4141 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4142 to be a good choice since it makes it far enough from the
4143 start of the data area as well as from the stack pointer.
4145 Please note that the environment is read-only until the monitor
4146 has been relocated to RAM and a RAM copy of the environment has been
4147 created; also, when using EEPROM you will have to use getenv_f()
4148 until then to read environment variables.
4150 The environment is protected by a CRC32 checksum. Before the monitor
4151 is relocated into RAM, as a result of a bad CRC you will be working
4152 with the compiled-in default environment - *silently*!!! [This is
4153 necessary, because the first environment variable we need is the
4154 "baudrate" setting for the console - if we have a bad CRC, we don't
4155 have any device yet where we could complain.]
4157 Note: once the monitor has been relocated, then it will complain if
4158 the default environment is used; a new CRC is computed as soon as you
4159 use the "saveenv" command to store a valid environment.
4161 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4162 Echo the inverted Ethernet link state to the fault LED.
4164 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4165 also needs to be defined.
4167 - CONFIG_SYS_FAULT_MII_ADDR:
4168 MII address of the PHY to check for the Ethernet link state.
4170 - CONFIG_NS16550_MIN_FUNCTIONS:
4171 Define this if you desire to only have use of the NS16550_init
4172 and NS16550_putc functions for the serial driver located at
4173 drivers/serial/ns16550.c. This option is useful for saving
4174 space for already greatly restricted images, including but not
4175 limited to NAND_SPL configurations.
4177 - CONFIG_DISPLAY_BOARDINFO
4178 Display information about the board that U-Boot is running on
4179 when U-Boot starts up. The board function checkboard() is called
4182 - CONFIG_DISPLAY_BOARDINFO_LATE
4183 Similar to the previous option, but display this information
4184 later, once stdio is running and output goes to the LCD, if
4187 - CONFIG_BOARD_SIZE_LIMIT:
4188 Maximum size of the U-Boot image. When defined, the
4189 build system checks that the actual size does not
4192 Low Level (hardware related) configuration options:
4193 ---------------------------------------------------
4195 - CONFIG_SYS_CACHELINE_SIZE:
4196 Cache Line Size of the CPU.
4198 - CONFIG_SYS_DEFAULT_IMMR:
4199 Default address of the IMMR after system reset.
4201 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4202 and RPXsuper) to be able to adjust the position of
4203 the IMMR register after a reset.
4205 - CONFIG_SYS_CCSRBAR_DEFAULT:
4206 Default (power-on reset) physical address of CCSR on Freescale
4209 - CONFIG_SYS_CCSRBAR:
4210 Virtual address of CCSR. On a 32-bit build, this is typically
4211 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4213 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4214 for cross-platform code that uses that macro instead.
4216 - CONFIG_SYS_CCSRBAR_PHYS:
4217 Physical address of CCSR. CCSR can be relocated to a new
4218 physical address, if desired. In this case, this macro should
4219 be set to that address. Otherwise, it should be set to the
4220 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4221 is typically relocated on 36-bit builds. It is recommended
4222 that this macro be defined via the _HIGH and _LOW macros:
4224 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4225 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4227 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4228 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4229 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4230 used in assembly code, so it must not contain typecasts or
4231 integer size suffixes (e.g. "ULL").
4233 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4234 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4235 used in assembly code, so it must not contain typecasts or
4236 integer size suffixes (e.g. "ULL").
4238 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4239 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4240 forced to a value that ensures that CCSR is not relocated.
4242 - Floppy Disk Support:
4243 CONFIG_SYS_FDC_DRIVE_NUMBER
4245 the default drive number (default value 0)
4247 CONFIG_SYS_ISA_IO_STRIDE
4249 defines the spacing between FDC chipset registers
4252 CONFIG_SYS_ISA_IO_OFFSET
4254 defines the offset of register from address. It
4255 depends on which part of the data bus is connected to
4256 the FDC chipset. (default value 0)
4258 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4259 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4262 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4263 fdc_hw_init() is called at the beginning of the FDC
4264 setup. fdc_hw_init() must be provided by the board
4265 source code. It is used to make hardware-dependent
4269 Most IDE controllers were designed to be connected with PCI
4270 interface. Only few of them were designed for AHB interface.
4271 When software is doing ATA command and data transfer to
4272 IDE devices through IDE-AHB controller, some additional
4273 registers accessing to these kind of IDE-AHB controller
4276 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4277 DO NOT CHANGE unless you know exactly what you're
4278 doing! (11-4) [MPC8xx/82xx systems only]
4280 - CONFIG_SYS_INIT_RAM_ADDR:
4282 Start address of memory area that can be used for
4283 initial data and stack; please note that this must be
4284 writable memory that is working WITHOUT special
4285 initialization, i. e. you CANNOT use normal RAM which
4286 will become available only after programming the
4287 memory controller and running certain initialization
4290 U-Boot uses the following memory types:
4291 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4292 - MPC824X: data cache
4293 - PPC4xx: data cache
4295 - CONFIG_SYS_GBL_DATA_OFFSET:
4297 Offset of the initial data structure in the memory
4298 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4299 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4300 data is located at the end of the available space
4301 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4302 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4303 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4304 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4307 On the MPC824X (or other systems that use the data
4308 cache for initial memory) the address chosen for
4309 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4310 point to an otherwise UNUSED address space between
4311 the top of RAM and the start of the PCI space.
4313 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4315 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4317 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4319 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4321 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4323 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4325 - CONFIG_SYS_OR_TIMING_SDRAM:
4328 - CONFIG_SYS_MAMR_PTA:
4329 periodic timer for refresh
4331 - CONFIG_SYS_DER: Debug Event Register (37-47)
4333 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4334 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4335 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4336 CONFIG_SYS_BR1_PRELIM:
4337 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4339 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4340 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4341 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4342 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4344 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4345 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4346 Machine Mode Register and Memory Periodic Timer
4347 Prescaler definitions (SDRAM timing)
4349 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4350 enable I2C microcode relocation patch (MPC8xx);
4351 define relocation offset in DPRAM [DSP2]
4353 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4354 enable SMC microcode relocation patch (MPC8xx);
4355 define relocation offset in DPRAM [SMC1]
4357 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4358 enable SPI microcode relocation patch (MPC8xx);
4359 define relocation offset in DPRAM [SCC4]
4361 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4362 Offset of the bootmode word in DPRAM used by post
4363 (Power On Self Tests). This definition overrides
4364 #define'd default value in commproc.h resp.
4367 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4368 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4369 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4370 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4371 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4372 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4373 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4374 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4375 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4377 - CONFIG_PCI_DISABLE_PCIE:
4378 Disable PCI-Express on systems where it is supported but not
4381 - CONFIG_PCI_ENUM_ONLY
4382 Only scan through and get the devices on the buses.
4383 Don't do any setup work, presumably because someone or
4384 something has already done it, and we don't need to do it
4385 a second time. Useful for platforms that are pre-booted
4386 by coreboot or similar.
4388 - CONFIG_PCI_INDIRECT_BRIDGE:
4389 Enable support for indirect PCI bridges.
4392 Chip has SRIO or not
4395 Board has SRIO 1 port available
4398 Board has SRIO 2 port available
4400 - CONFIG_SRIO_PCIE_BOOT_MASTER
4401 Board can support master function for Boot from SRIO and PCIE
4403 - CONFIG_SYS_SRIOn_MEM_VIRT:
4404 Virtual Address of SRIO port 'n' memory region
4406 - CONFIG_SYS_SRIOn_MEM_PHYS:
4407 Physical Address of SRIO port 'n' memory region
4409 - CONFIG_SYS_SRIOn_MEM_SIZE:
4410 Size of SRIO port 'n' memory region
4412 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4413 Defined to tell the NAND controller that the NAND chip is using
4415 Not all NAND drivers use this symbol.
4416 Example of drivers that use it:
4417 - drivers/mtd/nand/ndfc.c
4418 - drivers/mtd/nand/mxc_nand.c
4420 - CONFIG_SYS_NDFC_EBC0_CFG
4421 Sets the EBC0_CFG register for the NDFC. If not defined
4422 a default value will be used.
4425 Get DDR timing information from an I2C EEPROM. Common
4426 with pluggable memory modules such as SODIMMs
4429 I2C address of the SPD EEPROM
4431 - CONFIG_SYS_SPD_BUS_NUM
4432 If SPD EEPROM is on an I2C bus other than the first
4433 one, specify here. Note that the value must resolve
4434 to something your driver can deal with.
4436 - CONFIG_SYS_DDR_RAW_TIMING
4437 Get DDR timing information from other than SPD. Common with
4438 soldered DDR chips onboard without SPD. DDR raw timing
4439 parameters are extracted from datasheet and hard-coded into
4440 header files or board specific files.
4442 - CONFIG_FSL_DDR_INTERACTIVE
4443 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4445 - CONFIG_FSL_DDR_SYNC_REFRESH
4446 Enable sync of refresh for multiple controllers.
4448 - CONFIG_FSL_DDR_BIST
4449 Enable built-in memory test for Freescale DDR controllers.
4451 - CONFIG_SYS_83XX_DDR_USES_CS0
4452 Only for 83xx systems. If specified, then DDR should
4453 be configured using CS0 and CS1 instead of CS2 and CS3.
4455 - CONFIG_ETHER_ON_FEC[12]
4456 Define to enable FEC[12] on a 8xx series processor.
4458 - CONFIG_FEC[12]_PHY
4459 Define to the hardcoded PHY address which corresponds
4460 to the given FEC; i. e.
4461 #define CONFIG_FEC1_PHY 4
4462 means that the PHY with address 4 is connected to FEC1
4464 When set to -1, means to probe for first available.
4466 - CONFIG_FEC[12]_PHY_NORXERR
4467 The PHY does not have a RXERR line (RMII only).
4468 (so program the FEC to ignore it).
4471 Enable RMII mode for all FECs.
4472 Note that this is a global option, we can't
4473 have one FEC in standard MII mode and another in RMII mode.
4475 - CONFIG_CRC32_VERIFY
4476 Add a verify option to the crc32 command.
4479 => crc32 -v <address> <count> <crc32>
4481 Where address/count indicate a memory area
4482 and crc32 is the correct crc32 which the
4486 Add the "loopw" memory command. This only takes effect if
4487 the memory commands are activated globally (CONFIG_CMD_MEM).
4490 Add the "mdc" and "mwc" memory commands. These are cyclic
4495 This command will print 4 bytes (10,11,12,13) each 500 ms.
4497 => mwc.l 100 12345678 10
4498 This command will write 12345678 to address 100 all 10 ms.
4500 This only takes effect if the memory commands are activated
4501 globally (CONFIG_CMD_MEM).
4503 - CONFIG_SKIP_LOWLEVEL_INIT
4504 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4505 low level initializations (like setting up the memory
4506 controller) are omitted and/or U-Boot does not
4507 relocate itself into RAM.
4509 Normally this variable MUST NOT be defined. The only
4510 exception is when U-Boot is loaded (to RAM) by some
4511 other boot loader or by a debugger which performs
4512 these initializations itself.
4514 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4515 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4516 to be skipped. The normal CP15 init (such as enabling the
4517 instruction cache) is still performed.
4520 Modifies the behaviour of start.S when compiling a loader
4521 that is executed before the actual U-Boot. E.g. when
4522 compiling a NAND SPL.
4525 Modifies the behaviour of start.S when compiling a loader
4526 that is executed after the SPL and before the actual U-Boot.
4527 It is loaded by the SPL.
4529 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4530 Only for 85xx systems. If this variable is specified, the section
4531 .resetvec is not kept and the section .bootpg is placed in the
4532 previous 4k of the .text section.
4534 - CONFIG_ARCH_MAP_SYSMEM
4535 Generally U-Boot (and in particular the md command) uses
4536 effective address. It is therefore not necessary to regard
4537 U-Boot address as virtual addresses that need to be translated
4538 to physical addresses. However, sandbox requires this, since
4539 it maintains its own little RAM buffer which contains all
4540 addressable memory. This option causes some memory accesses
4541 to be mapped through map_sysmem() / unmap_sysmem().
4543 - CONFIG_X86_RESET_VECTOR
4544 If defined, the x86 reset vector code is included. This is not
4545 needed when U-Boot is running from Coreboot.
4548 Defines the MPU clock speed (in MHz).
4550 NOTE : currently only supported on AM335x platforms.
4552 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4553 Enables the RTC32K OSC on AM33xx based plattforms
4555 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4556 Option to disable subpage write in NAND driver
4557 driver that uses this:
4558 drivers/mtd/nand/davinci_nand.c
4560 Freescale QE/FMAN Firmware Support:
4561 -----------------------------------
4563 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4564 loading of "firmware", which is encoded in the QE firmware binary format.
4565 This firmware often needs to be loaded during U-Boot booting, so macros
4566 are used to identify the storage device (NOR flash, SPI, etc) and the address
4569 - CONFIG_SYS_FMAN_FW_ADDR
4570 The address in the storage device where the FMAN microcode is located. The
4571 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4574 - CONFIG_SYS_QE_FW_ADDR
4575 The address in the storage device where the QE microcode is located. The
4576 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4579 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4580 The maximum possible size of the firmware. The firmware binary format
4581 has a field that specifies the actual size of the firmware, but it
4582 might not be possible to read any part of the firmware unless some
4583 local storage is allocated to hold the entire firmware first.
4585 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4586 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4587 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4588 virtual address in NOR flash.
4590 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4591 Specifies that QE/FMAN firmware is located in NAND flash.
4592 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4594 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4595 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4596 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4598 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4599 Specifies that QE/FMAN firmware is located in the remote (master)
4600 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4601 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4602 window->master inbound window->master LAW->the ucode address in
4603 master's memory space.
4605 Freescale Layerscape Management Complex Firmware Support:
4606 ---------------------------------------------------------
4607 The Freescale Layerscape Management Complex (MC) supports the loading of
4609 This firmware often needs to be loaded during U-Boot booting, so macros
4610 are used to identify the storage device (NOR flash, SPI, etc) and the address
4613 - CONFIG_FSL_MC_ENET
4614 Enable the MC driver for Layerscape SoCs.
4616 Freescale Layerscape Debug Server Support:
4617 -------------------------------------------
4618 The Freescale Layerscape Debug Server Support supports the loading of
4619 "Debug Server firmware" and triggering SP boot-rom.
4620 This firmware often needs to be loaded during U-Boot booting.
4622 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4623 Define alignment of reserved memory MC requires
4628 In order to achieve reproducible builds, timestamps used in the U-Boot build
4629 process have to be set to a fixed value.
4631 This is done using the SOURCE_DATE_EPOCH environment variable.
4632 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4633 option for U-Boot or an environment variable in U-Boot.
4635 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4637 Building the Software:
4638 ======================
4640 Building U-Boot has been tested in several native build environments
4641 and in many different cross environments. Of course we cannot support
4642 all possibly existing versions of cross development tools in all
4643 (potentially obsolete) versions. In case of tool chain problems we
4644 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4645 which is extensively used to build and test U-Boot.
4647 If you are not using a native environment, it is assumed that you
4648 have GNU cross compiling tools available in your path. In this case,
4649 you must set the environment variable CROSS_COMPILE in your shell.
4650 Note that no changes to the Makefile or any other source files are
4651 necessary. For example using the ELDK on a 4xx CPU, please enter:
4653 $ CROSS_COMPILE=ppc_4xx-
4654 $ export CROSS_COMPILE
4656 Note: If you wish to generate Windows versions of the utilities in
4657 the tools directory you can use the MinGW toolchain
4658 (http://www.mingw.org). Set your HOST tools to the MinGW
4659 toolchain and execute 'make tools'. For example:
4661 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4663 Binaries such as tools/mkimage.exe will be created which can
4664 be executed on computers running Windows.
4666 U-Boot is intended to be simple to build. After installing the
4667 sources you must configure U-Boot for one specific board type. This
4672 where "NAME_defconfig" is the name of one of the existing configu-
4673 rations; see boards.cfg for supported names.
4675 Note: for some board special configuration names may exist; check if
4676 additional information is available from the board vendor; for
4677 instance, the TQM823L systems are available without (standard)
4678 or with LCD support. You can select such additional "features"
4679 when choosing the configuration, i. e.
4681 make TQM823L_defconfig
4682 - will configure for a plain TQM823L, i. e. no LCD support
4684 make TQM823L_LCD_defconfig
4685 - will configure for a TQM823L with U-Boot console on LCD
4690 Finally, type "make all", and you should get some working U-Boot
4691 images ready for download to / installation on your system:
4693 - "u-boot.bin" is a raw binary image
4694 - "u-boot" is an image in ELF binary format
4695 - "u-boot.srec" is in Motorola S-Record format
4697 By default the build is performed locally and the objects are saved
4698 in the source directory. One of the two methods can be used to change
4699 this behavior and build U-Boot to some external directory:
4701 1. Add O= to the make command line invocations:
4703 make O=/tmp/build distclean
4704 make O=/tmp/build NAME_defconfig
4705 make O=/tmp/build all
4707 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4709 export KBUILD_OUTPUT=/tmp/build
4714 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4718 Please be aware that the Makefiles assume you are using GNU make, so
4719 for instance on NetBSD you might need to use "gmake" instead of
4723 If the system board that you have is not listed, then you will need
4724 to port U-Boot to your hardware platform. To do this, follow these
4727 1. Create a new directory to hold your board specific code. Add any
4728 files you need. In your board directory, you will need at least
4729 the "Makefile" and a "<board>.c".
4730 2. Create a new configuration file "include/configs/<board>.h" for
4732 3. If you're porting U-Boot to a new CPU, then also create a new
4733 directory to hold your CPU specific code. Add any files you need.
4734 4. Run "make <board>_defconfig" with your new name.
4735 5. Type "make", and you should get a working "u-boot.srec" file
4736 to be installed on your target system.
4737 6. Debug and solve any problems that might arise.
4738 [Of course, this last step is much harder than it sounds.]
4741 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4742 ==============================================================
4744 If you have modified U-Boot sources (for instance added a new board
4745 or support for new devices, a new CPU, etc.) you are expected to
4746 provide feedback to the other developers. The feedback normally takes
4747 the form of a "patch", i. e. a context diff against a certain (latest
4748 official or latest in the git repository) version of U-Boot sources.
4750 But before you submit such a patch, please verify that your modifi-
4751 cation did not break existing code. At least make sure that *ALL* of
4752 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4753 just run the buildman script (tools/buildman/buildman), which will
4754 configure and build U-Boot for ALL supported system. Be warned, this
4755 will take a while. Please see the buildman README, or run 'buildman -H'
4759 See also "U-Boot Porting Guide" below.
4762 Monitor Commands - Overview:
4763 ============================
4765 go - start application at address 'addr'
4766 run - run commands in an environment variable
4767 bootm - boot application image from memory
4768 bootp - boot image via network using BootP/TFTP protocol
4769 bootz - boot zImage from memory
4770 tftpboot- boot image via network using TFTP protocol
4771 and env variables "ipaddr" and "serverip"
4772 (and eventually "gatewayip")
4773 tftpput - upload a file via network using TFTP protocol
4774 rarpboot- boot image via network using RARP/TFTP protocol
4775 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4776 loads - load S-Record file over serial line
4777 loadb - load binary file over serial line (kermit mode)
4779 mm - memory modify (auto-incrementing)
4780 nm - memory modify (constant address)
4781 mw - memory write (fill)
4783 cmp - memory compare
4784 crc32 - checksum calculation
4785 i2c - I2C sub-system
4786 sspi - SPI utility commands
4787 base - print or set address offset
4788 printenv- print environment variables
4789 setenv - set environment variables
4790 saveenv - save environment variables to persistent storage
4791 protect - enable or disable FLASH write protection
4792 erase - erase FLASH memory
4793 flinfo - print FLASH memory information
4794 nand - NAND memory operations (see doc/README.nand)
4795 bdinfo - print Board Info structure
4796 iminfo - print header information for application image
4797 coninfo - print console devices and informations
4798 ide - IDE sub-system
4799 loop - infinite loop on address range
4800 loopw - infinite write loop on address range
4801 mtest - simple RAM test
4802 icache - enable or disable instruction cache
4803 dcache - enable or disable data cache
4804 reset - Perform RESET of the CPU
4805 echo - echo args to console
4806 version - print monitor version
4807 help - print online help
4808 ? - alias for 'help'
4811 Monitor Commands - Detailed Description:
4812 ========================================
4816 For now: just type "help <command>".
4819 Environment Variables:
4820 ======================
4822 U-Boot supports user configuration using Environment Variables which
4823 can be made persistent by saving to Flash memory.
4825 Environment Variables are set using "setenv", printed using
4826 "printenv", and saved to Flash using "saveenv". Using "setenv"
4827 without a value can be used to delete a variable from the
4828 environment. As long as you don't save the environment you are
4829 working with an in-memory copy. In case the Flash area containing the
4830 environment is erased by accident, a default environment is provided.
4832 Some configuration options can be set using Environment Variables.
4834 List of environment variables (most likely not complete):
4836 baudrate - see CONFIG_BAUDRATE
4838 bootdelay - see CONFIG_BOOTDELAY
4840 bootcmd - see CONFIG_BOOTCOMMAND
4842 bootargs - Boot arguments when booting an RTOS image
4844 bootfile - Name of the image to load with TFTP
4846 bootm_low - Memory range available for image processing in the bootm
4847 command can be restricted. This variable is given as
4848 a hexadecimal number and defines lowest address allowed
4849 for use by the bootm command. See also "bootm_size"
4850 environment variable. Address defined by "bootm_low" is
4851 also the base of the initial memory mapping for the Linux
4852 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4855 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4856 This variable is given as a hexadecimal number and it
4857 defines the size of the memory region starting at base
4858 address bootm_low that is accessible by the Linux kernel
4859 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4860 as the default value if it is defined, and bootm_size is
4863 bootm_size - Memory range available for image processing in the bootm
4864 command can be restricted. This variable is given as
4865 a hexadecimal number and defines the size of the region
4866 allowed for use by the bootm command. See also "bootm_low"
4867 environment variable.
4869 updatefile - Location of the software update file on a TFTP server, used
4870 by the automatic software update feature. Please refer to
4871 documentation in doc/README.update for more details.
4873 autoload - if set to "no" (any string beginning with 'n'),
4874 "bootp" will just load perform a lookup of the
4875 configuration from the BOOTP server, but not try to
4876 load any image using TFTP
4878 autostart - if set to "yes", an image loaded using the "bootp",
4879 "rarpboot", "tftpboot" or "diskboot" commands will
4880 be automatically started (by internally calling
4883 If set to "no", a standalone image passed to the
4884 "bootm" command will be copied to the load address
4885 (and eventually uncompressed), but NOT be started.
4886 This can be used to load and uncompress arbitrary
4889 fdt_high - if set this restricts the maximum address that the
4890 flattened device tree will be copied into upon boot.
4891 For example, if you have a system with 1 GB memory
4892 at physical address 0x10000000, while Linux kernel
4893 only recognizes the first 704 MB as low memory, you
4894 may need to set fdt_high as 0x3C000000 to have the
4895 device tree blob be copied to the maximum address
4896 of the 704 MB low memory, so that Linux kernel can
4897 access it during the boot procedure.
4899 If this is set to the special value 0xFFFFFFFF then
4900 the fdt will not be copied at all on boot. For this
4901 to work it must reside in writable memory, have
4902 sufficient padding on the end of it for u-boot to
4903 add the information it needs into it, and the memory
4904 must be accessible by the kernel.
4906 fdtcontroladdr- if set this is the address of the control flattened
4907 device tree used by U-Boot when CONFIG_OF_CONTROL is
4910 i2cfast - (PPC405GP|PPC405EP only)
4911 if set to 'y' configures Linux I2C driver for fast
4912 mode (400kHZ). This environment variable is used in
4913 initialization code. So, for changes to be effective
4914 it must be saved and board must be reset.
4916 initrd_high - restrict positioning of initrd images:
4917 If this variable is not set, initrd images will be
4918 copied to the highest possible address in RAM; this
4919 is usually what you want since it allows for
4920 maximum initrd size. If for some reason you want to
4921 make sure that the initrd image is loaded below the
4922 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4923 variable to a value of "no" or "off" or "0".
4924 Alternatively, you can set it to a maximum upper
4925 address to use (U-Boot will still check that it
4926 does not overwrite the U-Boot stack and data).
4928 For instance, when you have a system with 16 MB
4929 RAM, and want to reserve 4 MB from use by Linux,
4930 you can do this by adding "mem=12M" to the value of
4931 the "bootargs" variable. However, now you must make
4932 sure that the initrd image is placed in the first
4933 12 MB as well - this can be done with
4935 setenv initrd_high 00c00000
4937 If you set initrd_high to 0xFFFFFFFF, this is an
4938 indication to U-Boot that all addresses are legal
4939 for the Linux kernel, including addresses in flash
4940 memory. In this case U-Boot will NOT COPY the
4941 ramdisk at all. This may be useful to reduce the
4942 boot time on your system, but requires that this
4943 feature is supported by your Linux kernel.
4945 ipaddr - IP address; needed for tftpboot command
4947 loadaddr - Default load address for commands like "bootp",
4948 "rarpboot", "tftpboot", "loadb" or "diskboot"
4950 loads_echo - see CONFIG_LOADS_ECHO
4952 serverip - TFTP server IP address; needed for tftpboot command
4954 bootretry - see CONFIG_BOOT_RETRY_TIME
4956 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4958 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4960 ethprime - controls which interface is used first.
4962 ethact - controls which interface is currently active.
4963 For example you can do the following
4965 => setenv ethact FEC
4966 => ping 192.168.0.1 # traffic sent on FEC
4967 => setenv ethact SCC
4968 => ping 10.0.0.1 # traffic sent on SCC
4970 ethrotate - When set to "no" U-Boot does not go through all
4971 available network interfaces.
4972 It just stays at the currently selected interface.
4974 netretry - When set to "no" each network operation will
4975 either succeed or fail without retrying.
4976 When set to "once" the network operation will
4977 fail when all the available network interfaces
4978 are tried once without success.
4979 Useful on scripts which control the retry operation
4982 npe_ucode - set load address for the NPE microcode
4984 silent_linux - If set then Linux will be told to boot silently, by
4985 changing the console to be empty. If "yes" it will be
4986 made silent. If "no" it will not be made silent. If
4987 unset, then it will be made silent if the U-Boot console
4990 tftpsrcp - If this is set, the value is used for TFTP's
4993 tftpdstp - If this is set, the value is used for TFTP's UDP
4994 destination port instead of the Well Know Port 69.
4996 tftpblocksize - Block size to use for TFTP transfers; if not set,
4997 we use the TFTP server's default block size
4999 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5000 seconds, minimum value is 1000 = 1 second). Defines
5001 when a packet is considered to be lost so it has to
5002 be retransmitted. The default is 5000 = 5 seconds.
5003 Lowering this value may make downloads succeed
5004 faster in networks with high packet loss rates or
5005 with unreliable TFTP servers.
5007 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5008 unit, minimum value = 0). Defines how many timeouts
5009 can happen during a single file transfer before that
5010 transfer is aborted. The default is 10, and 0 means
5011 'no timeouts allowed'. Increasing this value may help
5012 downloads succeed with high packet loss rates, or with
5013 unreliable TFTP servers or client hardware.
5015 vlan - When set to a value < 4095 the traffic over
5016 Ethernet is encapsulated/received over 802.1q
5019 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5020 Unsigned value, in milliseconds. If not set, the period will
5021 be either the default (28000), or a value based on
5022 CONFIG_NET_RETRY_COUNT, if defined. This value has
5023 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5025 The following image location variables contain the location of images
5026 used in booting. The "Image" column gives the role of the image and is
5027 not an environment variable name. The other columns are environment
5028 variable names. "File Name" gives the name of the file on a TFTP
5029 server, "RAM Address" gives the location in RAM the image will be
5030 loaded to, and "Flash Location" gives the image's address in NOR
5031 flash or offset in NAND flash.
5033 *Note* - these variables don't have to be defined for all boards, some
5034 boards currently use other variables for these purposes, and some
5035 boards use these variables for other purposes.
5037 Image File Name RAM Address Flash Location
5038 ----- --------- ----------- --------------
5039 u-boot u-boot u-boot_addr_r u-boot_addr
5040 Linux kernel bootfile kernel_addr_r kernel_addr
5041 device tree blob fdtfile fdt_addr_r fdt_addr
5042 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5044 The following environment variables may be used and automatically
5045 updated by the network boot commands ("bootp" and "rarpboot"),
5046 depending the information provided by your boot server:
5048 bootfile - see above
5049 dnsip - IP address of your Domain Name Server
5050 dnsip2 - IP address of your secondary Domain Name Server
5051 gatewayip - IP address of the Gateway (Router) to use
5052 hostname - Target hostname
5054 netmask - Subnet Mask
5055 rootpath - Pathname of the root filesystem on the NFS server
5056 serverip - see above
5059 There are two special Environment Variables:
5061 serial# - contains hardware identification information such
5062 as type string and/or serial number
5063 ethaddr - Ethernet address
5065 These variables can be set only once (usually during manufacturing of
5066 the board). U-Boot refuses to delete or overwrite these variables
5067 once they have been set once.
5070 Further special Environment Variables:
5072 ver - Contains the U-Boot version string as printed
5073 with the "version" command. This variable is
5074 readonly (see CONFIG_VERSION_VARIABLE).
5077 Please note that changes to some configuration parameters may take
5078 only effect after the next boot (yes, that's just like Windoze :-).
5081 Callback functions for environment variables:
5082 ---------------------------------------------
5084 For some environment variables, the behavior of u-boot needs to change
5085 when their values are changed. This functionality allows functions to
5086 be associated with arbitrary variables. On creation, overwrite, or
5087 deletion, the callback will provide the opportunity for some side
5088 effect to happen or for the change to be rejected.
5090 The callbacks are named and associated with a function using the
5091 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5093 These callbacks are associated with variables in one of two ways. The
5094 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5095 in the board configuration to a string that defines a list of
5096 associations. The list must be in the following format:
5098 entry = variable_name[:callback_name]
5101 If the callback name is not specified, then the callback is deleted.
5102 Spaces are also allowed anywhere in the list.
5104 Callbacks can also be associated by defining the ".callbacks" variable
5105 with the same list format above. Any association in ".callbacks" will
5106 override any association in the static list. You can define
5107 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5108 ".callbacks" environment variable in the default or embedded environment.
5110 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5111 regular expression. This allows multiple variables to be connected to
5112 the same callback without explicitly listing them all out.
5115 Command Line Parsing:
5116 =====================
5118 There are two different command line parsers available with U-Boot:
5119 the old "simple" one, and the much more powerful "hush" shell:
5121 Old, simple command line parser:
5122 --------------------------------
5124 - supports environment variables (through setenv / saveenv commands)
5125 - several commands on one line, separated by ';'
5126 - variable substitution using "... ${name} ..." syntax
5127 - special characters ('$', ';') can be escaped by prefixing with '\',
5129 setenv bootcmd bootm \${address}
5130 - You can also escape text by enclosing in single apostrophes, for example:
5131 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5136 - similar to Bourne shell, with control structures like
5137 if...then...else...fi, for...do...done; while...do...done,
5138 until...do...done, ...
5139 - supports environment ("global") variables (through setenv / saveenv
5140 commands) and local shell variables (through standard shell syntax
5141 "name=value"); only environment variables can be used with "run"
5147 (1) If a command line (or an environment variable executed by a "run"
5148 command) contains several commands separated by semicolon, and
5149 one of these commands fails, then the remaining commands will be
5152 (2) If you execute several variables with one call to run (i. e.
5153 calling run with a list of variables as arguments), any failing
5154 command will cause "run" to terminate, i. e. the remaining
5155 variables are not executed.
5157 Note for Redundant Ethernet Interfaces:
5158 =======================================
5160 Some boards come with redundant Ethernet interfaces; U-Boot supports
5161 such configurations and is capable of automatic selection of a
5162 "working" interface when needed. MAC assignment works as follows:
5164 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5165 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5166 "eth1addr" (=>eth1), "eth2addr", ...
5168 If the network interface stores some valid MAC address (for instance
5169 in SROM), this is used as default address if there is NO correspon-
5170 ding setting in the environment; if the corresponding environment
5171 variable is set, this overrides the settings in the card; that means:
5173 o If the SROM has a valid MAC address, and there is no address in the
5174 environment, the SROM's address is used.
5176 o If there is no valid address in the SROM, and a definition in the
5177 environment exists, then the value from the environment variable is
5180 o If both the SROM and the environment contain a MAC address, and
5181 both addresses are the same, this MAC address is used.
5183 o If both the SROM and the environment contain a MAC address, and the
5184 addresses differ, the value from the environment is used and a
5187 o If neither SROM nor the environment contain a MAC address, an error
5188 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5189 a random, locally-assigned MAC is used.
5191 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5192 will be programmed into hardware as part of the initialization process. This
5193 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5194 The naming convention is as follows:
5195 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5200 U-Boot is capable of booting (and performing other auxiliary operations on)
5201 images in two formats:
5203 New uImage format (FIT)
5204 -----------------------
5206 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5207 to Flattened Device Tree). It allows the use of images with multiple
5208 components (several kernels, ramdisks, etc.), with contents protected by
5209 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5215 Old image format is based on binary files which can be basically anything,
5216 preceded by a special header; see the definitions in include/image.h for
5217 details; basically, the header defines the following image properties:
5219 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5220 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5221 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5222 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5224 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5225 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5226 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5227 * Compression Type (uncompressed, gzip, bzip2)
5233 The header is marked by a special Magic Number, and both the header
5234 and the data portions of the image are secured against corruption by
5241 Although U-Boot should support any OS or standalone application
5242 easily, the main focus has always been on Linux during the design of
5245 U-Boot includes many features that so far have been part of some
5246 special "boot loader" code within the Linux kernel. Also, any
5247 "initrd" images to be used are no longer part of one big Linux image;
5248 instead, kernel and "initrd" are separate images. This implementation
5249 serves several purposes:
5251 - the same features can be used for other OS or standalone
5252 applications (for instance: using compressed images to reduce the
5253 Flash memory footprint)
5255 - it becomes much easier to port new Linux kernel versions because
5256 lots of low-level, hardware dependent stuff are done by U-Boot
5258 - the same Linux kernel image can now be used with different "initrd"
5259 images; of course this also means that different kernel images can
5260 be run with the same "initrd". This makes testing easier (you don't
5261 have to build a new "zImage.initrd" Linux image when you just
5262 change a file in your "initrd"). Also, a field-upgrade of the
5263 software is easier now.
5269 Porting Linux to U-Boot based systems:
5270 ---------------------------------------
5272 U-Boot cannot save you from doing all the necessary modifications to
5273 configure the Linux device drivers for use with your target hardware
5274 (no, we don't intend to provide a full virtual machine interface to
5277 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5279 Just make sure your machine specific header file (for instance
5280 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5281 Information structure as we define in include/asm-<arch>/u-boot.h,
5282 and make sure that your definition of IMAP_ADDR uses the same value
5283 as your U-Boot configuration in CONFIG_SYS_IMMR.
5285 Note that U-Boot now has a driver model, a unified model for drivers.
5286 If you are adding a new driver, plumb it into driver model. If there
5287 is no uclass available, you are encouraged to create one. See
5291 Configuring the Linux kernel:
5292 -----------------------------
5294 No specific requirements for U-Boot. Make sure you have some root
5295 device (initial ramdisk, NFS) for your target system.
5298 Building a Linux Image:
5299 -----------------------
5301 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5302 not used. If you use recent kernel source, a new build target
5303 "uImage" will exist which automatically builds an image usable by
5304 U-Boot. Most older kernels also have support for a "pImage" target,
5305 which was introduced for our predecessor project PPCBoot and uses a
5306 100% compatible format.
5310 make TQM850L_defconfig
5315 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5316 encapsulate a compressed Linux kernel image with header information,
5317 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5319 * build a standard "vmlinux" kernel image (in ELF binary format):
5321 * convert the kernel into a raw binary image:
5323 ${CROSS_COMPILE}-objcopy -O binary \
5324 -R .note -R .comment \
5325 -S vmlinux linux.bin
5327 * compress the binary image:
5331 * package compressed binary image for U-Boot:
5333 mkimage -A ppc -O linux -T kernel -C gzip \
5334 -a 0 -e 0 -n "Linux Kernel Image" \
5335 -d linux.bin.gz uImage
5338 The "mkimage" tool can also be used to create ramdisk images for use
5339 with U-Boot, either separated from the Linux kernel image, or
5340 combined into one file. "mkimage" encapsulates the images with a 64
5341 byte header containing information about target architecture,
5342 operating system, image type, compression method, entry points, time
5343 stamp, CRC32 checksums, etc.
5345 "mkimage" can be called in two ways: to verify existing images and
5346 print the header information, or to build new images.
5348 In the first form (with "-l" option) mkimage lists the information
5349 contained in the header of an existing U-Boot image; this includes
5350 checksum verification:
5352 tools/mkimage -l image
5353 -l ==> list image header information
5355 The second form (with "-d" option) is used to build a U-Boot image
5356 from a "data file" which is used as image payload:
5358 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5359 -n name -d data_file image
5360 -A ==> set architecture to 'arch'
5361 -O ==> set operating system to 'os'
5362 -T ==> set image type to 'type'
5363 -C ==> set compression type 'comp'
5364 -a ==> set load address to 'addr' (hex)
5365 -e ==> set entry point to 'ep' (hex)
5366 -n ==> set image name to 'name'
5367 -d ==> use image data from 'datafile'
5369 Right now, all Linux kernels for PowerPC systems use the same load
5370 address (0x00000000), but the entry point address depends on the
5373 - 2.2.x kernels have the entry point at 0x0000000C,
5374 - 2.3.x and later kernels have the entry point at 0x00000000.
5376 So a typical call to build a U-Boot image would read:
5378 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5379 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5380 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5381 > examples/uImage.TQM850L
5382 Image Name: 2.4.4 kernel for TQM850L
5383 Created: Wed Jul 19 02:34:59 2000
5384 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5385 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5386 Load Address: 0x00000000
5387 Entry Point: 0x00000000
5389 To verify the contents of the image (or check for corruption):
5391 -> tools/mkimage -l examples/uImage.TQM850L
5392 Image Name: 2.4.4 kernel for TQM850L
5393 Created: Wed Jul 19 02:34:59 2000
5394 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5395 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5396 Load Address: 0x00000000
5397 Entry Point: 0x00000000
5399 NOTE: for embedded systems where boot time is critical you can trade
5400 speed for memory and install an UNCOMPRESSED image instead: this
5401 needs more space in Flash, but boots much faster since it does not
5402 need to be uncompressed:
5404 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5405 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5406 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5407 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5408 > examples/uImage.TQM850L-uncompressed
5409 Image Name: 2.4.4 kernel for TQM850L
5410 Created: Wed Jul 19 02:34:59 2000
5411 Image Type: PowerPC Linux Kernel Image (uncompressed)
5412 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5413 Load Address: 0x00000000
5414 Entry Point: 0x00000000
5417 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5418 when your kernel is intended to use an initial ramdisk:
5420 -> tools/mkimage -n 'Simple Ramdisk Image' \
5421 > -A ppc -O linux -T ramdisk -C gzip \
5422 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5423 Image Name: Simple Ramdisk Image
5424 Created: Wed Jan 12 14:01:50 2000
5425 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5426 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5427 Load Address: 0x00000000
5428 Entry Point: 0x00000000
5430 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5431 option performs the converse operation of the mkimage's second form (the "-d"
5432 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5435 tools/dumpimage -i image -T type -p position data_file
5436 -i ==> extract from the 'image' a specific 'data_file'
5437 -T ==> set image type to 'type'
5438 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5441 Installing a Linux Image:
5442 -------------------------
5444 To downloading a U-Boot image over the serial (console) interface,
5445 you must convert the image to S-Record format:
5447 objcopy -I binary -O srec examples/image examples/image.srec
5449 The 'objcopy' does not understand the information in the U-Boot
5450 image header, so the resulting S-Record file will be relative to
5451 address 0x00000000. To load it to a given address, you need to
5452 specify the target address as 'offset' parameter with the 'loads'
5455 Example: install the image to address 0x40100000 (which on the
5456 TQM8xxL is in the first Flash bank):
5458 => erase 40100000 401FFFFF
5464 ## Ready for S-Record download ...
5465 ~>examples/image.srec
5466 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5468 15989 15990 15991 15992
5469 [file transfer complete]
5471 ## Start Addr = 0x00000000
5474 You can check the success of the download using the 'iminfo' command;
5475 this includes a checksum verification so you can be sure no data
5476 corruption happened:
5480 ## Checking Image at 40100000 ...
5481 Image Name: 2.2.13 for initrd on TQM850L
5482 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5483 Data Size: 335725 Bytes = 327 kB = 0 MB
5484 Load Address: 00000000
5485 Entry Point: 0000000c
5486 Verifying Checksum ... OK
5492 The "bootm" command is used to boot an application that is stored in
5493 memory (RAM or Flash). In case of a Linux kernel image, the contents
5494 of the "bootargs" environment variable is passed to the kernel as
5495 parameters. You can check and modify this variable using the
5496 "printenv" and "setenv" commands:
5499 => printenv bootargs
5500 bootargs=root=/dev/ram
5502 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5504 => printenv bootargs
5505 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5508 ## Booting Linux kernel at 40020000 ...
5509 Image Name: 2.2.13 for NFS on TQM850L
5510 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5511 Data Size: 381681 Bytes = 372 kB = 0 MB
5512 Load Address: 00000000
5513 Entry Point: 0000000c
5514 Verifying Checksum ... OK
5515 Uncompressing Kernel Image ... OK
5516 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
5517 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5518 time_init: decrementer frequency = 187500000/60
5519 Calibrating delay loop... 49.77 BogoMIPS
5520 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5523 If you want to boot a Linux kernel with initial RAM disk, you pass
5524 the memory addresses of both the kernel and the initrd image (PPBCOOT
5525 format!) to the "bootm" command:
5527 => imi 40100000 40200000
5529 ## Checking Image at 40100000 ...
5530 Image Name: 2.2.13 for initrd on TQM850L
5531 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5532 Data Size: 335725 Bytes = 327 kB = 0 MB
5533 Load Address: 00000000
5534 Entry Point: 0000000c
5535 Verifying Checksum ... OK
5537 ## Checking Image at 40200000 ...
5538 Image Name: Simple Ramdisk Image
5539 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5540 Data Size: 566530 Bytes = 553 kB = 0 MB
5541 Load Address: 00000000
5542 Entry Point: 00000000
5543 Verifying Checksum ... OK
5545 => bootm 40100000 40200000
5546 ## Booting Linux kernel at 40100000 ...
5547 Image Name: 2.2.13 for initrd on TQM850L
5548 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5549 Data Size: 335725 Bytes = 327 kB = 0 MB
5550 Load Address: 00000000
5551 Entry Point: 0000000c
5552 Verifying Checksum ... OK
5553 Uncompressing Kernel Image ... OK
5554 ## Loading RAMDisk Image at 40200000 ...
5555 Image Name: Simple Ramdisk Image
5556 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5557 Data Size: 566530 Bytes = 553 kB = 0 MB
5558 Load Address: 00000000
5559 Entry Point: 00000000
5560 Verifying Checksum ... OK
5561 Loading Ramdisk ... OK
5562 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
5563 Boot arguments: root=/dev/ram
5564 time_init: decrementer frequency = 187500000/60
5565 Calibrating delay loop... 49.77 BogoMIPS
5567 RAMDISK: Compressed image found at block 0
5568 VFS: Mounted root (ext2 filesystem).
5572 Boot Linux and pass a flat device tree:
5575 First, U-Boot must be compiled with the appropriate defines. See the section
5576 titled "Linux Kernel Interface" above for a more in depth explanation. The
5577 following is an example of how to start a kernel and pass an updated
5583 oft=oftrees/mpc8540ads.dtb
5584 => tftp $oftaddr $oft
5585 Speed: 1000, full duplex
5587 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5588 Filename 'oftrees/mpc8540ads.dtb'.
5589 Load address: 0x300000
5592 Bytes transferred = 4106 (100a hex)
5593 => tftp $loadaddr $bootfile
5594 Speed: 1000, full duplex
5596 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5598 Load address: 0x200000
5599 Loading:############
5601 Bytes transferred = 1029407 (fb51f hex)
5606 => bootm $loadaddr - $oftaddr
5607 ## Booting image at 00200000 ...
5608 Image Name: Linux-2.6.17-dirty
5609 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5610 Data Size: 1029343 Bytes = 1005.2 kB
5611 Load Address: 00000000
5612 Entry Point: 00000000
5613 Verifying Checksum ... OK
5614 Uncompressing Kernel Image ... OK
5615 Booting using flat device tree at 0x300000
5616 Using MPC85xx ADS machine description
5617 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5621 More About U-Boot Image Types:
5622 ------------------------------
5624 U-Boot supports the following image types:
5626 "Standalone Programs" are directly runnable in the environment
5627 provided by U-Boot; it is expected that (if they behave
5628 well) you can continue to work in U-Boot after return from
5629 the Standalone Program.
5630 "OS Kernel Images" are usually images of some Embedded OS which
5631 will take over control completely. Usually these programs
5632 will install their own set of exception handlers, device
5633 drivers, set up the MMU, etc. - this means, that you cannot
5634 expect to re-enter U-Boot except by resetting the CPU.
5635 "RAMDisk Images" are more or less just data blocks, and their
5636 parameters (address, size) are passed to an OS kernel that is
5638 "Multi-File Images" contain several images, typically an OS
5639 (Linux) kernel image and one or more data images like
5640 RAMDisks. This construct is useful for instance when you want
5641 to boot over the network using BOOTP etc., where the boot
5642 server provides just a single image file, but you want to get
5643 for instance an OS kernel and a RAMDisk image.
5645 "Multi-File Images" start with a list of image sizes, each
5646 image size (in bytes) specified by an "uint32_t" in network
5647 byte order. This list is terminated by an "(uint32_t)0".
5648 Immediately after the terminating 0 follow the images, one by
5649 one, all aligned on "uint32_t" boundaries (size rounded up to
5650 a multiple of 4 bytes).
5652 "Firmware Images" are binary images containing firmware (like
5653 U-Boot or FPGA images) which usually will be programmed to
5656 "Script files" are command sequences that will be executed by
5657 U-Boot's command interpreter; this feature is especially
5658 useful when you configure U-Boot to use a real shell (hush)
5659 as command interpreter.
5661 Booting the Linux zImage:
5662 -------------------------
5664 On some platforms, it's possible to boot Linux zImage. This is done
5665 using the "bootz" command. The syntax of "bootz" command is the same
5666 as the syntax of "bootm" command.
5668 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5669 kernel with raw initrd images. The syntax is slightly different, the
5670 address of the initrd must be augmented by it's size, in the following
5671 format: "<initrd addres>:<initrd size>".
5677 One of the features of U-Boot is that you can dynamically load and
5678 run "standalone" applications, which can use some resources of
5679 U-Boot like console I/O functions or interrupt services.
5681 Two simple examples are included with the sources:
5686 'examples/hello_world.c' contains a small "Hello World" Demo
5687 application; it is automatically compiled when you build U-Boot.
5688 It's configured to run at address 0x00040004, so you can play with it
5692 ## Ready for S-Record download ...
5693 ~>examples/hello_world.srec
5694 1 2 3 4 5 6 7 8 9 10 11 ...
5695 [file transfer complete]
5697 ## Start Addr = 0x00040004
5699 => go 40004 Hello World! This is a test.
5700 ## Starting application at 0x00040004 ...
5711 Hit any key to exit ...
5713 ## Application terminated, rc = 0x0
5715 Another example, which demonstrates how to register a CPM interrupt
5716 handler with the U-Boot code, can be found in 'examples/timer.c'.
5717 Here, a CPM timer is set up to generate an interrupt every second.
5718 The interrupt service routine is trivial, just printing a '.'
5719 character, but this is just a demo program. The application can be
5720 controlled by the following keys:
5722 ? - print current values og the CPM Timer registers
5723 b - enable interrupts and start timer
5724 e - stop timer and disable interrupts
5725 q - quit application
5728 ## Ready for S-Record download ...
5729 ~>examples/timer.srec
5730 1 2 3 4 5 6 7 8 9 10 11 ...
5731 [file transfer complete]
5733 ## Start Addr = 0x00040004
5736 ## Starting application at 0x00040004 ...
5739 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5742 [q, b, e, ?] Set interval 1000000 us
5745 [q, b, e, ?] ........
5746 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5749 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5752 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5755 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5757 [q, b, e, ?] ...Stopping timer
5759 [q, b, e, ?] ## Application terminated, rc = 0x0
5765 Over time, many people have reported problems when trying to use the
5766 "minicom" terminal emulation program for serial download. I (wd)
5767 consider minicom to be broken, and recommend not to use it. Under
5768 Unix, I recommend to use C-Kermit for general purpose use (and
5769 especially for kermit binary protocol download ("loadb" command), and
5770 use "cu" for S-Record download ("loads" command). See
5771 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5772 for help with kermit.
5775 Nevertheless, if you absolutely want to use it try adding this
5776 configuration to your "File transfer protocols" section:
5778 Name Program Name U/D FullScr IO-Red. Multi
5779 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5780 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5786 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5787 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5789 Building requires a cross environment; it is known to work on
5790 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5791 need gmake since the Makefiles are not compatible with BSD make).
5792 Note that the cross-powerpc package does not install include files;
5793 attempting to build U-Boot will fail because <machine/ansi.h> is
5794 missing. This file has to be installed and patched manually:
5796 # cd /usr/pkg/cross/powerpc-netbsd/include
5798 # ln -s powerpc machine
5799 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5800 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5802 Native builds *don't* work due to incompatibilities between native
5803 and U-Boot include files.
5805 Booting assumes that (the first part of) the image booted is a
5806 stage-2 loader which in turn loads and then invokes the kernel
5807 proper. Loader sources will eventually appear in the NetBSD source
5808 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5809 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5812 Implementation Internals:
5813 =========================
5815 The following is not intended to be a complete description of every
5816 implementation detail. However, it should help to understand the
5817 inner workings of U-Boot and make it easier to port it to custom
5821 Initial Stack, Global Data:
5822 ---------------------------
5824 The implementation of U-Boot is complicated by the fact that U-Boot
5825 starts running out of ROM (flash memory), usually without access to
5826 system RAM (because the memory controller is not initialized yet).
5827 This means that we don't have writable Data or BSS segments, and BSS
5828 is not initialized as zero. To be able to get a C environment working
5829 at all, we have to allocate at least a minimal stack. Implementation
5830 options for this are defined and restricted by the CPU used: Some CPU
5831 models provide on-chip memory (like the IMMR area on MPC8xx and
5832 MPC826x processors), on others (parts of) the data cache can be
5833 locked as (mis-) used as memory, etc.
5835 Chris Hallinan posted a good summary of these issues to the
5836 U-Boot mailing list:
5838 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5839 From: "Chris Hallinan" <clh@net1plus.com>
5840 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5843 Correct me if I'm wrong, folks, but the way I understand it
5844 is this: Using DCACHE as initial RAM for Stack, etc, does not
5845 require any physical RAM backing up the cache. The cleverness
5846 is that the cache is being used as a temporary supply of
5847 necessary storage before the SDRAM controller is setup. It's
5848 beyond the scope of this list to explain the details, but you
5849 can see how this works by studying the cache architecture and
5850 operation in the architecture and processor-specific manuals.
5852 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5853 is another option for the system designer to use as an
5854 initial stack/RAM area prior to SDRAM being available. Either
5855 option should work for you. Using CS 4 should be fine if your
5856 board designers haven't used it for something that would
5857 cause you grief during the initial boot! It is frequently not
5860 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5861 with your processor/board/system design. The default value
5862 you will find in any recent u-boot distribution in
5863 walnut.h should work for you. I'd set it to a value larger
5864 than your SDRAM module. If you have a 64MB SDRAM module, set
5865 it above 400_0000. Just make sure your board has no resources
5866 that are supposed to respond to that address! That code in
5867 start.S has been around a while and should work as is when
5868 you get the config right.
5873 It is essential to remember this, since it has some impact on the C
5874 code for the initialization procedures:
5876 * Initialized global data (data segment) is read-only. Do not attempt
5879 * Do not use any uninitialized global data (or implicitly initialized
5880 as zero data - BSS segment) at all - this is undefined, initiali-
5881 zation is performed later (when relocating to RAM).
5883 * Stack space is very limited. Avoid big data buffers or things like
5886 Having only the stack as writable memory limits means we cannot use
5887 normal global data to share information between the code. But it
5888 turned out that the implementation of U-Boot can be greatly
5889 simplified by making a global data structure (gd_t) available to all
5890 functions. We could pass a pointer to this data as argument to _all_
5891 functions, but this would bloat the code. Instead we use a feature of
5892 the GCC compiler (Global Register Variables) to share the data: we
5893 place a pointer (gd) to the global data into a register which we
5894 reserve for this purpose.
5896 When choosing a register for such a purpose we are restricted by the
5897 relevant (E)ABI specifications for the current architecture, and by
5898 GCC's implementation.
5900 For PowerPC, the following registers have specific use:
5902 R2: reserved for system use
5903 R3-R4: parameter passing and return values
5904 R5-R10: parameter passing
5905 R13: small data area pointer
5909 (U-Boot also uses R12 as internal GOT pointer. r12
5910 is a volatile register so r12 needs to be reset when
5911 going back and forth between asm and C)
5913 ==> U-Boot will use R2 to hold a pointer to the global data
5915 Note: on PPC, we could use a static initializer (since the
5916 address of the global data structure is known at compile time),
5917 but it turned out that reserving a register results in somewhat
5918 smaller code - although the code savings are not that big (on
5919 average for all boards 752 bytes for the whole U-Boot image,
5920 624 text + 127 data).
5922 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5923 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5925 ==> U-Boot will use P3 to hold a pointer to the global data
5927 On ARM, the following registers are used:
5929 R0: function argument word/integer result
5930 R1-R3: function argument word
5931 R9: platform specific
5932 R10: stack limit (used only if stack checking is enabled)
5933 R11: argument (frame) pointer
5934 R12: temporary workspace
5937 R15: program counter
5939 ==> U-Boot will use R9 to hold a pointer to the global data
5941 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5943 On Nios II, the ABI is documented here:
5944 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5946 ==> U-Boot will use gp to hold a pointer to the global data
5948 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5949 to access small data sections, so gp is free.
5951 On NDS32, the following registers are used:
5953 R0-R1: argument/return
5955 R15: temporary register for assembler
5956 R16: trampoline register
5957 R28: frame pointer (FP)
5958 R29: global pointer (GP)
5959 R30: link register (LP)
5960 R31: stack pointer (SP)
5961 PC: program counter (PC)
5963 ==> U-Boot will use R10 to hold a pointer to the global data
5965 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5966 or current versions of GCC may "optimize" the code too much.
5971 U-Boot runs in system state and uses physical addresses, i.e. the
5972 MMU is not used either for address mapping nor for memory protection.
5974 The available memory is mapped to fixed addresses using the memory
5975 controller. In this process, a contiguous block is formed for each
5976 memory type (Flash, SDRAM, SRAM), even when it consists of several
5977 physical memory banks.
5979 U-Boot is installed in the first 128 kB of the first Flash bank (on
5980 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5981 booting and sizing and initializing DRAM, the code relocates itself
5982 to the upper end of DRAM. Immediately below the U-Boot code some
5983 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5984 configuration setting]. Below that, a structure with global Board
5985 Info data is placed, followed by the stack (growing downward).
5987 Additionally, some exception handler code is copied to the low 8 kB
5988 of DRAM (0x00000000 ... 0x00001FFF).
5990 So a typical memory configuration with 16 MB of DRAM could look like
5993 0x0000 0000 Exception Vector code
5996 0x0000 2000 Free for Application Use
6002 0x00FB FF20 Monitor Stack (Growing downward)
6003 0x00FB FFAC Board Info Data and permanent copy of global data
6004 0x00FC 0000 Malloc Arena
6007 0x00FE 0000 RAM Copy of Monitor Code
6008 ... eventually: LCD or video framebuffer
6009 ... eventually: pRAM (Protected RAM - unchanged by reset)
6010 0x00FF FFFF [End of RAM]
6013 System Initialization:
6014 ----------------------
6016 In the reset configuration, U-Boot starts at the reset entry point
6017 (on most PowerPC systems at address 0x00000100). Because of the reset
6018 configuration for CS0# this is a mirror of the on board Flash memory.
6019 To be able to re-map memory U-Boot then jumps to its link address.
6020 To be able to implement the initialization code in C, a (small!)
6021 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6022 which provide such a feature like MPC8xx or MPC8260), or in a locked
6023 part of the data cache. After that, U-Boot initializes the CPU core,
6024 the caches and the SIU.
6026 Next, all (potentially) available memory banks are mapped using a
6027 preliminary mapping. For example, we put them on 512 MB boundaries
6028 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6029 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6030 programmed for SDRAM access. Using the temporary configuration, a
6031 simple memory test is run that determines the size of the SDRAM
6034 When there is more than one SDRAM bank, and the banks are of
6035 different size, the largest is mapped first. For equal size, the first
6036 bank (CS2#) is mapped first. The first mapping is always for address
6037 0x00000000, with any additional banks following immediately to create
6038 contiguous memory starting from 0.
6040 Then, the monitor installs itself at the upper end of the SDRAM area
6041 and allocates memory for use by malloc() and for the global Board
6042 Info data; also, the exception vector code is copied to the low RAM
6043 pages, and the final stack is set up.
6045 Only after this relocation will you have a "normal" C environment;
6046 until that you are restricted in several ways, mostly because you are
6047 running from ROM, and because the code will have to be relocated to a
6051 U-Boot Porting Guide:
6052 ----------------------
6054 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6058 int main(int argc, char *argv[])
6060 sighandler_t no_more_time;
6062 signal(SIGALRM, no_more_time);
6063 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6065 if (available_money > available_manpower) {
6066 Pay consultant to port U-Boot;
6070 Download latest U-Boot source;
6072 Subscribe to u-boot mailing list;
6075 email("Hi, I am new to U-Boot, how do I get started?");
6078 Read the README file in the top level directory;
6079 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6080 Read applicable doc/*.README;
6081 Read the source, Luke;
6082 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6085 if (available_money > toLocalCurrency ($2500))
6088 Add a lot of aggravation and time;
6090 if (a similar board exists) { /* hopefully... */
6091 cp -a board/<similar> board/<myboard>
6092 cp include/configs/<similar>.h include/configs/<myboard>.h
6094 Create your own board support subdirectory;
6095 Create your own board include/configs/<myboard>.h file;
6097 Edit new board/<myboard> files
6098 Edit new include/configs/<myboard>.h
6103 Add / modify source code;
6107 email("Hi, I am having problems...");
6109 Send patch file to the U-Boot email list;
6110 if (reasonable critiques)
6111 Incorporate improvements from email list code review;
6113 Defend code as written;
6119 void no_more_time (int sig)
6128 All contributions to U-Boot should conform to the Linux kernel
6129 coding style; see the file "Documentation/CodingStyle" and the script
6130 "scripts/Lindent" in your Linux kernel source directory.
6132 Source files originating from a different project (for example the
6133 MTD subsystem) are generally exempt from these guidelines and are not
6134 reformatted to ease subsequent migration to newer versions of those
6137 Please note that U-Boot is implemented in C (and to some small parts in
6138 Assembler); no C++ is used, so please do not use C++ style comments (//)
6141 Please also stick to the following formatting rules:
6142 - remove any trailing white space
6143 - use TAB characters for indentation and vertical alignment, not spaces
6144 - make sure NOT to use DOS '\r\n' line feeds
6145 - do not add more than 2 consecutive empty lines to source files
6146 - do not add trailing empty lines to source files
6148 Submissions which do not conform to the standards may be returned
6149 with a request to reformat the changes.
6155 Since the number of patches for U-Boot is growing, we need to
6156 establish some rules. Submissions which do not conform to these rules
6157 may be rejected, even when they contain important and valuable stuff.
6159 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6161 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6162 see http://lists.denx.de/mailman/listinfo/u-boot
6164 When you send a patch, please include the following information with
6167 * For bug fixes: a description of the bug and how your patch fixes
6168 this bug. Please try to include a way of demonstrating that the
6169 patch actually fixes something.
6171 * For new features: a description of the feature and your
6174 * A CHANGELOG entry as plaintext (separate from the patch)
6176 * For major contributions, add a MAINTAINERS file with your
6177 information and associated file and directory references.
6179 * When you add support for a new board, don't forget to add a
6180 maintainer e-mail address to the boards.cfg file, too.
6182 * If your patch adds new configuration options, don't forget to
6183 document these in the README file.
6185 * The patch itself. If you are using git (which is *strongly*
6186 recommended) you can easily generate the patch using the
6187 "git format-patch". If you then use "git send-email" to send it to
6188 the U-Boot mailing list, you will avoid most of the common problems
6189 with some other mail clients.
6191 If you cannot use git, use "diff -purN OLD NEW". If your version of
6192 diff does not support these options, then get the latest version of
6195 The current directory when running this command shall be the parent
6196 directory of the U-Boot source tree (i. e. please make sure that
6197 your patch includes sufficient directory information for the
6200 We prefer patches as plain text. MIME attachments are discouraged,
6201 and compressed attachments must not be used.
6203 * If one logical set of modifications affects or creates several
6204 files, all these changes shall be submitted in a SINGLE patch file.
6206 * Changesets that contain different, unrelated modifications shall be
6207 submitted as SEPARATE patches, one patch per changeset.
6212 * Before sending the patch, run the buildman script on your patched
6213 source tree and make sure that no errors or warnings are reported
6214 for any of the boards.
6216 * Keep your modifications to the necessary minimum: A patch
6217 containing several unrelated changes or arbitrary reformats will be
6218 returned with a request to re-formatting / split it.
6220 * If you modify existing code, make sure that your new code does not
6221 add to the memory footprint of the code ;-) Small is beautiful!
6222 When adding new features, these should compile conditionally only
6223 (using #ifdef), and the resulting code with the new feature
6224 disabled must not need more memory than the old code without your
6227 * Remember that there is a size limit of 100 kB per message on the
6228 u-boot mailing list. Bigger patches will be moderated. If they are
6229 reasonable and not too big, they will be acknowledged. But patches
6230 bigger than the size limit should be avoided.
projects / oweals / u-boot.git / blob