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 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
834 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
835 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
836 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
837 CONFIG_CMD_DTT * Digital Therm and Thermostat
838 CONFIG_CMD_ECHO echo arguments
839 CONFIG_CMD_EDITENV edit env variable
840 CONFIG_CMD_EEPROM * EEPROM read/write support
841 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
842 CONFIG_CMD_ELF * bootelf, bootvx
843 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
844 CONFIG_CMD_ENV_FLAGS * display details about env flags
845 CONFIG_CMD_ENV_EXISTS * check existence of env variable
846 CONFIG_CMD_EXPORTENV * export the environment
847 CONFIG_CMD_EXT2 * ext2 command support
848 CONFIG_CMD_EXT4 * ext4 command support
849 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
850 that work for multiple fs types
851 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
852 CONFIG_CMD_SAVEENV saveenv
853 CONFIG_CMD_FDC * Floppy Disk Support
854 CONFIG_CMD_FAT * FAT command support
855 CONFIG_CMD_FLASH flinfo, erase, protect
856 CONFIG_CMD_FPGA FPGA device initialization support
857 CONFIG_CMD_FUSE * Device fuse support
858 CONFIG_CMD_GETTIME * Get time since boot
859 CONFIG_CMD_GO * the 'go' command (exec code)
860 CONFIG_CMD_GREPENV * search environment
861 CONFIG_CMD_HASH * calculate hash / digest
862 CONFIG_CMD_I2C * I2C serial bus support
863 CONFIG_CMD_IDE * IDE harddisk support
864 CONFIG_CMD_IMI iminfo
865 CONFIG_CMD_IMLS List all images found in NOR flash
866 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
867 CONFIG_CMD_IMMAP * IMMR dump support
868 CONFIG_CMD_IOTRACE * I/O tracing for debugging
869 CONFIG_CMD_IMPORTENV * import an environment
870 CONFIG_CMD_INI * import data from an ini file into the env
871 CONFIG_CMD_IRQ * irqinfo
872 CONFIG_CMD_ITEST Integer/string test of 2 values
873 CONFIG_CMD_JFFS2 * JFFS2 Support
874 CONFIG_CMD_KGDB * kgdb
875 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
876 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
878 CONFIG_CMD_LOADB loadb
879 CONFIG_CMD_LOADS loads
880 CONFIG_CMD_MD5SUM * print md5 message digest
881 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
882 CONFIG_CMD_MEMINFO * Display detailed memory information
883 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
885 CONFIG_CMD_MEMTEST * mtest
886 CONFIG_CMD_MISC Misc functions like sleep etc
887 CONFIG_CMD_MMC * MMC memory mapped support
888 CONFIG_CMD_MII * MII utility commands
889 CONFIG_CMD_MTDPARTS * MTD partition support
890 CONFIG_CMD_NAND * NAND support
891 CONFIG_CMD_NET bootp, tftpboot, rarpboot
892 CONFIG_CMD_NFS NFS support
893 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
894 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
895 CONFIG_CMD_PCI * pciinfo
896 CONFIG_CMD_PCMCIA * PCMCIA support
897 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
899 CONFIG_CMD_PORTIO * Port I/O
900 CONFIG_CMD_READ * Read raw data from partition
901 CONFIG_CMD_REGINFO * Register dump
902 CONFIG_CMD_RUN run command in env variable
903 CONFIG_CMD_SANDBOX * sb command to access sandbox features
904 CONFIG_CMD_SAVES * save S record dump
905 CONFIG_SCSI * SCSI Support
906 CONFIG_CMD_SDRAM * print SDRAM configuration information
907 (requires CONFIG_CMD_I2C)
908 CONFIG_CMD_SETGETDCR Support for DCR Register access
910 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
911 CONFIG_CMD_SHA1SUM * print sha1 memory digest
912 (requires CONFIG_CMD_MEMORY)
913 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
914 CONFIG_CMD_SOURCE "source" command Support
915 CONFIG_CMD_SPI * SPI serial bus support
916 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
917 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
918 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
919 CONFIG_CMD_TIMER * access to the system tick timer
920 CONFIG_CMD_USB * USB support
921 CONFIG_CMD_CDP * Cisco Discover Protocol support
922 CONFIG_CMD_MFSL * Microblaze FSL support
923 CONFIG_CMD_XIMG Load part of Multi Image
924 CONFIG_CMD_UUID * Generate random UUID or GUID string
926 EXAMPLE: If you want all functions except of network
927 support you can write:
929 #include "config_cmd_all.h"
930 #undef CONFIG_CMD_NET
933 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
935 Note: Don't enable the "icache" and "dcache" commands
936 (configuration option CONFIG_CMD_CACHE) unless you know
937 what you (and your U-Boot users) are doing. Data
938 cache cannot be enabled on systems like the 8xx or
939 8260 (where accesses to the IMMR region must be
940 uncached), and it cannot be disabled on all other
941 systems where we (mis-) use the data cache to hold an
942 initial stack and some data.
945 XXX - this list needs to get updated!
947 - Removal of commands
948 If no commands are needed to boot, you can disable
949 CONFIG_CMDLINE to remove them. In this case, the command line
950 will not be available, and when U-Boot wants to execute the
951 boot command (on start-up) it will call board_run_command()
952 instead. This can reduce image size significantly for very
953 simple boot procedures.
955 - Regular expression support:
957 If this variable is defined, U-Boot is linked against
958 the SLRE (Super Light Regular Expression) library,
959 which adds regex support to some commands, as for
960 example "env grep" and "setexpr".
964 If this variable is defined, U-Boot will use a device tree
965 to configure its devices, instead of relying on statically
966 compiled #defines in the board file. This option is
967 experimental and only available on a few boards. The device
968 tree is available in the global data as gd->fdt_blob.
970 U-Boot needs to get its device tree from somewhere. This can
971 be done using one of the three options below:
974 If this variable is defined, U-Boot will embed a device tree
975 binary in its image. This device tree file should be in the
976 board directory and called <soc>-<board>.dts. The binary file
977 is then picked up in board_init_f() and made available through
978 the global data structure as gd->blob.
981 If this variable is defined, U-Boot will build a device tree
982 binary. It will be called u-boot.dtb. Architecture-specific
983 code will locate it at run-time. Generally this works by:
985 cat u-boot.bin u-boot.dtb >image.bin
987 and in fact, U-Boot does this for you, creating a file called
988 u-boot-dtb.bin which is useful in the common case. You can
989 still use the individual files if you need something more
993 If this variable is defined, U-Boot will use the device tree
994 provided by the board at runtime instead of embedding one with
995 the image. Only boards defining board_fdt_blob_setup() support
996 this option (see include/fdtdec.h file).
1000 If this variable is defined, it enables watchdog
1001 support for the SoC. There must be support in the SoC
1002 specific code for a watchdog. For the 8xx and 8260
1003 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1004 register. When supported for a specific SoC is
1005 available, then no further board specific code should
1006 be needed to use it.
1009 When using a watchdog circuitry external to the used
1010 SoC, then define this variable and provide board
1011 specific code for the "hw_watchdog_reset" function.
1013 CONFIG_AT91_HW_WDT_TIMEOUT
1014 specify the timeout in seconds. default 2 seconds.
1017 CONFIG_VERSION_VARIABLE
1018 If this variable is defined, an environment variable
1019 named "ver" is created by U-Boot showing the U-Boot
1020 version as printed by the "version" command.
1021 Any change to this variable will be reverted at the
1026 When CONFIG_CMD_DATE is selected, the type of the RTC
1027 has to be selected, too. Define exactly one of the
1030 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1031 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1032 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1033 CONFIG_RTC_MC146818 - use MC146818 RTC
1034 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1035 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1036 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1037 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1038 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1039 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1040 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1041 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1042 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1045 Note that if the RTC uses I2C, then the I2C interface
1046 must also be configured. See I2C Support, below.
1049 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1051 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1052 chip-ngpio pairs that tell the PCA953X driver the number of
1053 pins supported by a particular chip.
1055 Note that if the GPIO device uses I2C, then the I2C interface
1056 must also be configured. See I2C Support, below.
1059 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1060 accesses and can checksum them or write a list of them out
1061 to memory. See the 'iotrace' command for details. This is
1062 useful for testing device drivers since it can confirm that
1063 the driver behaves the same way before and after a code
1064 change. Currently this is supported on sandbox and arm. To
1065 add support for your architecture, add '#include <iotrace.h>'
1066 to the bottom of arch/<arch>/include/asm/io.h and test.
1068 Example output from the 'iotrace stats' command is below.
1069 Note that if the trace buffer is exhausted, the checksum will
1070 still continue to operate.
1073 Start: 10000000 (buffer start address)
1074 Size: 00010000 (buffer size)
1075 Offset: 00000120 (current buffer offset)
1076 Output: 10000120 (start + offset)
1077 Count: 00000018 (number of trace records)
1078 CRC32: 9526fb66 (CRC32 of all trace records)
1080 - Timestamp Support:
1082 When CONFIG_TIMESTAMP is selected, the timestamp
1083 (date and time) of an image is printed by image
1084 commands like bootm or iminfo. This option is
1085 automatically enabled when you select CONFIG_CMD_DATE .
1087 - Partition Labels (disklabels) Supported:
1088 Zero or more of the following:
1089 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1090 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1091 Intel architecture, USB sticks, etc.
1092 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1093 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1094 bootloader. Note 2TB partition limit; see
1096 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1098 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1099 CONFIG_SCSI) you must configure support for at
1100 least one non-MTD partition type as well.
1103 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1104 board configurations files but used nowhere!
1106 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1107 be performed by calling the function
1108 ide_set_reset(int reset)
1109 which has to be defined in a board specific file
1114 Set this to enable ATAPI support.
1119 Set this to enable support for disks larger than 137GB
1120 Also look at CONFIG_SYS_64BIT_LBA.
1121 Whithout these , LBA48 support uses 32bit variables and will 'only'
1122 support disks up to 2.1TB.
1124 CONFIG_SYS_64BIT_LBA:
1125 When enabled, makes the IDE subsystem use 64bit sector addresses.
1129 At the moment only there is only support for the
1130 SYM53C8XX SCSI controller; define
1131 CONFIG_SCSI_SYM53C8XX to enable it.
1133 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1134 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1135 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1136 maximum numbers of LUNs, SCSI ID's and target
1138 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1140 The environment variable 'scsidevs' is set to the number of
1141 SCSI devices found during the last scan.
1143 - NETWORK Support (PCI):
1145 Support for Intel 8254x/8257x gigabit chips.
1148 Utility code for direct access to the SPI bus on Intel 8257x.
1149 This does not do anything useful unless you set at least one
1150 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1152 CONFIG_E1000_SPI_GENERIC
1153 Allow generic access to the SPI bus on the Intel 8257x, for
1154 example with the "sspi" command.
1157 Management command for E1000 devices. When used on devices
1158 with SPI support you can reprogram the EEPROM from U-Boot.
1161 Support for Intel 82557/82559/82559ER chips.
1162 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1163 write routine for first time initialisation.
1166 Support for Digital 2114x chips.
1167 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1168 modem chip initialisation (KS8761/QS6611).
1171 Support for National dp83815 chips.
1174 Support for National dp8382[01] gigabit chips.
1176 - NETWORK Support (other):
1178 CONFIG_DRIVER_AT91EMAC
1179 Support for AT91RM9200 EMAC.
1182 Define this to use reduced MII inteface
1184 CONFIG_DRIVER_AT91EMAC_QUIET
1185 If this defined, the driver is quiet.
1186 The driver doen't show link status messages.
1188 CONFIG_CALXEDA_XGMAC
1189 Support for the Calxeda XGMAC device
1192 Support for SMSC's LAN91C96 chips.
1194 CONFIG_LAN91C96_USE_32_BIT
1195 Define this to enable 32 bit addressing
1198 Support for SMSC's LAN91C111 chip
1200 CONFIG_SMC91111_BASE
1201 Define this to hold the physical address
1202 of the device (I/O space)
1204 CONFIG_SMC_USE_32_BIT
1205 Define this if data bus is 32 bits
1207 CONFIG_SMC_USE_IOFUNCS
1208 Define this to use i/o functions instead of macros
1209 (some hardware wont work with macros)
1211 CONFIG_DRIVER_TI_EMAC
1212 Support for davinci emac
1214 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1215 Define this if you have more then 3 PHYs.
1218 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1220 CONFIG_FTGMAC100_EGIGA
1221 Define this to use GE link update with gigabit PHY.
1222 Define this if FTGMAC100 is connected to gigabit PHY.
1223 If your system has 10/100 PHY only, it might not occur
1224 wrong behavior. Because PHY usually return timeout or
1225 useless data when polling gigabit status and gigabit
1226 control registers. This behavior won't affect the
1227 correctnessof 10/100 link speed update.
1230 Support for SMSC's LAN911x and LAN921x chips
1233 Define this to hold the physical address
1234 of the device (I/O space)
1236 CONFIG_SMC911X_32_BIT
1237 Define this if data bus is 32 bits
1239 CONFIG_SMC911X_16_BIT
1240 Define this if data bus is 16 bits. If your processor
1241 automatically converts one 32 bit word to two 16 bit
1242 words you may also try CONFIG_SMC911X_32_BIT.
1245 Support for Renesas on-chip Ethernet controller
1247 CONFIG_SH_ETHER_USE_PORT
1248 Define the number of ports to be used
1250 CONFIG_SH_ETHER_PHY_ADDR
1251 Define the ETH PHY's address
1253 CONFIG_SH_ETHER_CACHE_WRITEBACK
1254 If this option is set, the driver enables cache flush.
1258 Support for PWM module on the imx6.
1262 Support TPM devices.
1264 CONFIG_TPM_TIS_INFINEON
1265 Support for Infineon i2c bus TPM devices. Only one device
1266 per system is supported at this time.
1268 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1269 Define the burst count bytes upper limit
1272 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1274 CONFIG_TPM_ST33ZP24_I2C
1275 Support for STMicroelectronics ST33ZP24 I2C devices.
1276 Requires TPM_ST33ZP24 and I2C.
1278 CONFIG_TPM_ST33ZP24_SPI
1279 Support for STMicroelectronics ST33ZP24 SPI devices.
1280 Requires TPM_ST33ZP24 and SPI.
1282 CONFIG_TPM_ATMEL_TWI
1283 Support for Atmel TWI TPM device. Requires I2C support.
1286 Support for generic parallel port TPM devices. Only one device
1287 per system is supported at this time.
1289 CONFIG_TPM_TIS_BASE_ADDRESS
1290 Base address where the generic TPM device is mapped
1291 to. Contemporary x86 systems usually map it at
1295 Add tpm monitor functions.
1296 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1297 provides monitor access to authorized functions.
1300 Define this to enable the TPM support library which provides
1301 functional interfaces to some TPM commands.
1302 Requires support for a TPM device.
1304 CONFIG_TPM_AUTH_SESSIONS
1305 Define this to enable authorized functions in the TPM library.
1306 Requires CONFIG_TPM and CONFIG_SHA1.
1309 At the moment only the UHCI host controller is
1310 supported (PIP405, MIP405, MPC5200); define
1311 CONFIG_USB_UHCI to enable it.
1312 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1313 and define CONFIG_USB_STORAGE to enable the USB
1316 Supported are USB Keyboards and USB Floppy drives
1318 MPC5200 USB requires additional defines:
1320 for 528 MHz Clock: 0x0001bbbb
1324 for differential drivers: 0x00001000
1325 for single ended drivers: 0x00005000
1326 for differential drivers on PSC3: 0x00000100
1327 for single ended drivers on PSC3: 0x00004100
1328 CONFIG_SYS_USB_EVENT_POLL
1329 May be defined to allow interrupt polling
1330 instead of using asynchronous interrupts
1332 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1333 txfilltuning field in the EHCI controller on reset.
1335 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1336 HW module registers.
1339 Define the below if you wish to use the USB console.
1340 Once firmware is rebuilt from a serial console issue the
1341 command "setenv stdin usbtty; setenv stdout usbtty" and
1342 attach your USB cable. The Unix command "dmesg" should print
1343 it has found a new device. The environment variable usbtty
1344 can be set to gserial or cdc_acm to enable your device to
1345 appear to a USB host as a Linux gserial device or a
1346 Common Device Class Abstract Control Model serial device.
1347 If you select usbtty = gserial you should be able to enumerate
1349 # modprobe usbserial vendor=0xVendorID product=0xProductID
1350 else if using cdc_acm, simply setting the environment
1351 variable usbtty to be cdc_acm should suffice. The following
1352 might be defined in YourBoardName.h
1355 Define this to build a UDC device
1358 Define this to have a tty type of device available to
1359 talk to the UDC device
1362 Define this to enable the high speed support for usb
1363 device and usbtty. If this feature is enabled, a routine
1364 int is_usbd_high_speed(void)
1365 also needs to be defined by the driver to dynamically poll
1366 whether the enumeration has succeded at high speed or full
1369 CONFIG_SYS_CONSOLE_IS_IN_ENV
1370 Define this if you want stdin, stdout &/or stderr to
1374 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1375 Derive USB clock from external clock "blah"
1376 - CONFIG_SYS_USB_EXTC_CLK 0x02
1378 If you have a USB-IF assigned VendorID then you may wish to
1379 define your own vendor specific values either in BoardName.h
1380 or directly in usbd_vendor_info.h. If you don't define
1381 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1382 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1383 should pretend to be a Linux device to it's target host.
1385 CONFIG_USBD_MANUFACTURER
1386 Define this string as the name of your company for
1387 - CONFIG_USBD_MANUFACTURER "my company"
1389 CONFIG_USBD_PRODUCT_NAME
1390 Define this string as the name of your product
1391 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1393 CONFIG_USBD_VENDORID
1394 Define this as your assigned Vendor ID from the USB
1395 Implementors Forum. This *must* be a genuine Vendor ID
1396 to avoid polluting the USB namespace.
1397 - CONFIG_USBD_VENDORID 0xFFFF
1399 CONFIG_USBD_PRODUCTID
1400 Define this as the unique Product ID
1402 - CONFIG_USBD_PRODUCTID 0xFFFF
1404 - ULPI Layer Support:
1405 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1406 the generic ULPI layer. The generic layer accesses the ULPI PHY
1407 via the platform viewport, so you need both the genric layer and
1408 the viewport enabled. Currently only Chipidea/ARC based
1409 viewport is supported.
1410 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1411 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1412 If your ULPI phy needs a different reference clock than the
1413 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1414 the appropriate value in Hz.
1417 The MMC controller on the Intel PXA is supported. To
1418 enable this define CONFIG_MMC. The MMC can be
1419 accessed from the boot prompt by mapping the device
1420 to physical memory similar to flash. Command line is
1421 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1422 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1425 Support for Renesas on-chip MMCIF controller
1427 CONFIG_SH_MMCIF_ADDR
1428 Define the base address of MMCIF registers
1431 Define the clock frequency for MMCIF
1433 CONFIG_SUPPORT_EMMC_BOOT
1434 Enable some additional features of the eMMC boot partitions.
1436 CONFIG_SUPPORT_EMMC_RPMB
1437 Enable the commands for reading, writing and programming the
1438 key for the Replay Protection Memory Block partition in eMMC.
1440 - USB Device Firmware Update (DFU) class support:
1441 CONFIG_USB_FUNCTION_DFU
1442 This enables the USB portion of the DFU USB class
1445 This enables the command "dfu" which is used to have
1446 U-Boot create a DFU class device via USB. This command
1447 requires that the "dfu_alt_info" environment variable be
1448 set and define the alt settings to expose to the host.
1451 This enables support for exposing (e)MMC devices via DFU.
1454 This enables support for exposing NAND devices via DFU.
1457 This enables support for exposing RAM via DFU.
1458 Note: DFU spec refer to non-volatile memory usage, but
1459 allow usages beyond the scope of spec - here RAM usage,
1460 one that would help mostly the developer.
1462 CONFIG_SYS_DFU_DATA_BUF_SIZE
1463 Dfu transfer uses a buffer before writing data to the
1464 raw storage device. Make the size (in bytes) of this buffer
1465 configurable. The size of this buffer is also configurable
1466 through the "dfu_bufsiz" environment variable.
1468 CONFIG_SYS_DFU_MAX_FILE_SIZE
1469 When updating files rather than the raw storage device,
1470 we use a static buffer to copy the file into and then write
1471 the buffer once we've been given the whole file. Define
1472 this to the maximum filesize (in bytes) for the buffer.
1473 Default is 4 MiB if undefined.
1475 DFU_DEFAULT_POLL_TIMEOUT
1476 Poll timeout [ms], is the timeout a device can send to the
1477 host. The host must wait for this timeout before sending
1478 a subsequent DFU_GET_STATUS request to the device.
1480 DFU_MANIFEST_POLL_TIMEOUT
1481 Poll timeout [ms], which the device sends to the host when
1482 entering dfuMANIFEST state. Host waits this timeout, before
1483 sending again an USB request to the device.
1485 - USB Device Android Fastboot support:
1486 CONFIG_USB_FUNCTION_FASTBOOT
1487 This enables the USB part of the fastboot gadget
1490 This enables the command "fastboot" which enables the Android
1491 fastboot mode for the platform's USB device. Fastboot is a USB
1492 protocol for downloading images, flashing and device control
1493 used on Android devices.
1494 See doc/README.android-fastboot for more information.
1496 CONFIG_ANDROID_BOOT_IMAGE
1497 This enables support for booting images which use the Android
1498 image format header.
1500 CONFIG_FASTBOOT_BUF_ADDR
1501 The fastboot protocol requires a large memory buffer for
1502 downloads. Define this to the starting RAM address to use for
1505 CONFIG_FASTBOOT_BUF_SIZE
1506 The fastboot protocol requires a large memory buffer for
1507 downloads. This buffer should be as large as possible for a
1508 platform. Define this to the size available RAM for fastboot.
1510 CONFIG_FASTBOOT_FLASH
1511 The fastboot protocol includes a "flash" command for writing
1512 the downloaded image to a non-volatile storage device. Define
1513 this to enable the "fastboot flash" command.
1515 CONFIG_FASTBOOT_FLASH_MMC_DEV
1516 The fastboot "flash" command requires additional information
1517 regarding the non-volatile storage device. Define this to
1518 the eMMC device that fastboot should use to store the image.
1520 CONFIG_FASTBOOT_GPT_NAME
1521 The fastboot "flash" command supports writing the downloaded
1522 image to the Protective MBR and the Primary GUID Partition
1523 Table. (Additionally, this downloaded image is post-processed
1524 to generate and write the Backup GUID Partition Table.)
1525 This occurs when the specified "partition name" on the
1526 "fastboot flash" command line matches this value.
1527 The default is "gpt" if undefined.
1529 CONFIG_FASTBOOT_MBR_NAME
1530 The fastboot "flash" command supports writing the downloaded
1532 This occurs when the "partition name" specified on the
1533 "fastboot flash" command line matches this value.
1534 If not defined the default value "mbr" is used.
1536 - Journaling Flash filesystem support:
1538 Define these for a default partition on a NAND device
1540 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1541 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1542 Define these for a default partition on a NOR device
1544 - FAT(File Allocation Table) filesystem write function support:
1547 Define this to enable support for saving memory data as a
1548 file in FAT formatted partition.
1550 This will also enable the command "fatwrite" enabling the
1551 user to write files to FAT.
1553 - FAT(File Allocation Table) filesystem cluster size:
1554 CONFIG_FS_FAT_MAX_CLUSTSIZE
1556 Define the max cluster size for fat operations else
1557 a default value of 65536 will be defined.
1560 See Kconfig help for available keyboard drivers.
1564 Define this to enable a custom keyboard support.
1565 This simply calls drv_keyboard_init() which must be
1566 defined in your board-specific files. This option is deprecated
1567 and is only used by novena. For new boards, use driver model
1572 Enable the Freescale DIU video driver. Reference boards for
1573 SOCs that have a DIU should define this macro to enable DIU
1574 support, and should also define these other macros:
1579 CONFIG_VIDEO_SW_CURSOR
1580 CONFIG_VGA_AS_SINGLE_DEVICE
1582 CONFIG_VIDEO_BMP_LOGO
1584 The DIU driver will look for the 'video-mode' environment
1585 variable, and if defined, enable the DIU as a console during
1586 boot. See the documentation file doc/README.video for a
1587 description of this variable.
1589 - LCD Support: CONFIG_LCD
1591 Define this to enable LCD support (for output to LCD
1592 display); also select one of the supported displays
1593 by defining one of these:
1597 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1599 CONFIG_NEC_NL6448AC33:
1601 NEC NL6448AC33-18. Active, color, single scan.
1603 CONFIG_NEC_NL6448BC20
1605 NEC NL6448BC20-08. 6.5", 640x480.
1606 Active, color, single scan.
1608 CONFIG_NEC_NL6448BC33_54
1610 NEC NL6448BC33-54. 10.4", 640x480.
1611 Active, color, single scan.
1615 Sharp 320x240. Active, color, single scan.
1616 It isn't 16x9, and I am not sure what it is.
1618 CONFIG_SHARP_LQ64D341
1620 Sharp LQ64D341 display, 640x480.
1621 Active, color, single scan.
1625 HLD1045 display, 640x480.
1626 Active, color, single scan.
1630 Optrex CBL50840-2 NF-FW 99 22 M5
1632 Hitachi LMG6912RPFC-00T
1636 320x240. Black & white.
1638 CONFIG_LCD_ALIGNMENT
1640 Normally the LCD is page-aligned (typically 4KB). If this is
1641 defined then the LCD will be aligned to this value instead.
1642 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1643 here, since it is cheaper to change data cache settings on
1644 a per-section basis.
1649 Sometimes, for example if the display is mounted in portrait
1650 mode or even if it's mounted landscape but rotated by 180degree,
1651 we need to rotate our content of the display relative to the
1652 framebuffer, so that user can read the messages which are
1654 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1655 initialized with a given rotation from "vl_rot" out of
1656 "vidinfo_t" which is provided by the board specific code.
1657 The value for vl_rot is coded as following (matching to
1658 fbcon=rotate:<n> linux-kernel commandline):
1659 0 = no rotation respectively 0 degree
1660 1 = 90 degree rotation
1661 2 = 180 degree rotation
1662 3 = 270 degree rotation
1664 If CONFIG_LCD_ROTATION is not defined, the console will be
1665 initialized with 0degree rotation.
1669 Support drawing of RLE8-compressed bitmaps on the LCD.
1673 Enables an 'i2c edid' command which can read EDID
1674 information over I2C from an attached LCD display.
1676 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1678 If this option is set, the environment is checked for
1679 a variable "splashimage". If found, the usual display
1680 of logo, copyright and system information on the LCD
1681 is suppressed and the BMP image at the address
1682 specified in "splashimage" is loaded instead. The
1683 console is redirected to the "nulldev", too. This
1684 allows for a "silent" boot where a splash screen is
1685 loaded very quickly after power-on.
1687 CONFIG_SPLASHIMAGE_GUARD
1689 If this option is set, then U-Boot will prevent the environment
1690 variable "splashimage" from being set to a problematic address
1691 (see doc/README.displaying-bmps).
1692 This option is useful for targets where, due to alignment
1693 restrictions, an improperly aligned BMP image will cause a data
1694 abort. If you think you will not have problems with unaligned
1695 accesses (for example because your toolchain prevents them)
1696 there is no need to set this option.
1698 CONFIG_SPLASH_SCREEN_ALIGN
1700 If this option is set the splash image can be freely positioned
1701 on the screen. Environment variable "splashpos" specifies the
1702 position as "x,y". If a positive number is given it is used as
1703 number of pixel from left/top. If a negative number is given it
1704 is used as number of pixel from right/bottom. You can also
1705 specify 'm' for centering the image.
1708 setenv splashpos m,m
1709 => image at center of screen
1711 setenv splashpos 30,20
1712 => image at x = 30 and y = 20
1714 setenv splashpos -10,m
1715 => vertically centered image
1716 at x = dspWidth - bmpWidth - 9
1718 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1720 If this option is set, additionally to standard BMP
1721 images, gzipped BMP images can be displayed via the
1722 splashscreen support or the bmp command.
1724 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1726 If this option is set, 8-bit RLE compressed BMP images
1727 can be displayed via the splashscreen support or the
1730 - Compression support:
1733 Enabled by default to support gzip compressed images.
1737 If this option is set, support for bzip2 compressed
1738 images is included. If not, only uncompressed and gzip
1739 compressed images are supported.
1741 NOTE: the bzip2 algorithm requires a lot of RAM, so
1742 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1747 If this option is set, support for lzma compressed
1750 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1751 requires an amount of dynamic memory that is given by the
1754 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1756 Where lc and lp stand for, respectively, Literal context bits
1757 and Literal pos bits.
1759 This value is upper-bounded by 14MB in the worst case. Anyway,
1760 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1761 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1762 a very small buffer.
1764 Use the lzmainfo tool to determinate the lc and lp values and
1765 then calculate the amount of needed dynamic memory (ensuring
1766 the appropriate CONFIG_SYS_MALLOC_LEN value).
1770 If this option is set, support for LZO compressed images
1776 The address of PHY on MII bus.
1778 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1780 The clock frequency of the MII bus
1784 If this option is set, support for speed/duplex
1785 detection of gigabit PHY is included.
1787 CONFIG_PHY_RESET_DELAY
1789 Some PHY like Intel LXT971A need extra delay after
1790 reset before any MII register access is possible.
1791 For such PHY, set this option to the usec delay
1792 required. (minimum 300usec for LXT971A)
1794 CONFIG_PHY_CMD_DELAY (ppc4xx)
1796 Some PHY like Intel LXT971A need extra delay after
1797 command issued before MII status register can be read
1802 Define a default value for the IP address to use for
1803 the default Ethernet interface, in case this is not
1804 determined through e.g. bootp.
1805 (Environment variable "ipaddr")
1807 - Server IP address:
1810 Defines a default value for the IP address of a TFTP
1811 server to contact when using the "tftboot" command.
1812 (Environment variable "serverip")
1814 CONFIG_KEEP_SERVERADDR
1816 Keeps the server's MAC address, in the env 'serveraddr'
1817 for passing to bootargs (like Linux's netconsole option)
1819 - Gateway IP address:
1822 Defines a default value for the IP address of the
1823 default router where packets to other networks are
1825 (Environment variable "gatewayip")
1830 Defines a default value for the subnet mask (or
1831 routing prefix) which is used to determine if an IP
1832 address belongs to the local subnet or needs to be
1833 forwarded through a router.
1834 (Environment variable "netmask")
1836 - Multicast TFTP Mode:
1839 Defines whether you want to support multicast TFTP as per
1840 rfc-2090; for example to work with atftp. Lets lots of targets
1841 tftp down the same boot image concurrently. Note: the Ethernet
1842 driver in use must provide a function: mcast() to join/leave a
1845 - BOOTP Recovery Mode:
1846 CONFIG_BOOTP_RANDOM_DELAY
1848 If you have many targets in a network that try to
1849 boot using BOOTP, you may want to avoid that all
1850 systems send out BOOTP requests at precisely the same
1851 moment (which would happen for instance at recovery
1852 from a power failure, when all systems will try to
1853 boot, thus flooding the BOOTP server. Defining
1854 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1855 inserted before sending out BOOTP requests. The
1856 following delays are inserted then:
1858 1st BOOTP request: delay 0 ... 1 sec
1859 2nd BOOTP request: delay 0 ... 2 sec
1860 3rd BOOTP request: delay 0 ... 4 sec
1862 BOOTP requests: delay 0 ... 8 sec
1864 CONFIG_BOOTP_ID_CACHE_SIZE
1866 BOOTP packets are uniquely identified using a 32-bit ID. The
1867 server will copy the ID from client requests to responses and
1868 U-Boot will use this to determine if it is the destination of
1869 an incoming response. Some servers will check that addresses
1870 aren't in use before handing them out (usually using an ARP
1871 ping) and therefore take up to a few hundred milliseconds to
1872 respond. Network congestion may also influence the time it
1873 takes for a response to make it back to the client. If that
1874 time is too long, U-Boot will retransmit requests. In order
1875 to allow earlier responses to still be accepted after these
1876 retransmissions, U-Boot's BOOTP client keeps a small cache of
1877 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1878 cache. The default is to keep IDs for up to four outstanding
1879 requests. Increasing this will allow U-Boot to accept offers
1880 from a BOOTP client in networks with unusually high latency.
1882 - DHCP Advanced Options:
1883 You can fine tune the DHCP functionality by defining
1884 CONFIG_BOOTP_* symbols:
1886 CONFIG_BOOTP_SUBNETMASK
1887 CONFIG_BOOTP_GATEWAY
1888 CONFIG_BOOTP_HOSTNAME
1889 CONFIG_BOOTP_NISDOMAIN
1890 CONFIG_BOOTP_BOOTPATH
1891 CONFIG_BOOTP_BOOTFILESIZE
1894 CONFIG_BOOTP_SEND_HOSTNAME
1895 CONFIG_BOOTP_NTPSERVER
1896 CONFIG_BOOTP_TIMEOFFSET
1897 CONFIG_BOOTP_VENDOREX
1898 CONFIG_BOOTP_MAY_FAIL
1900 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1901 environment variable, not the BOOTP server.
1903 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1904 after the configured retry count, the call will fail
1905 instead of starting over. This can be used to fail over
1906 to Link-local IP address configuration if the DHCP server
1909 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1910 serverip from a DHCP server, it is possible that more
1911 than one DNS serverip is offered to the client.
1912 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1913 serverip will be stored in the additional environment
1914 variable "dnsip2". The first DNS serverip is always
1915 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1918 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1919 to do a dynamic update of a DNS server. To do this, they
1920 need the hostname of the DHCP requester.
1921 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1922 of the "hostname" environment variable is passed as
1923 option 12 to the DHCP server.
1925 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1927 A 32bit value in microseconds for a delay between
1928 receiving a "DHCP Offer" and sending the "DHCP Request".
1929 This fixes a problem with certain DHCP servers that don't
1930 respond 100% of the time to a "DHCP request". E.g. On an
1931 AT91RM9200 processor running at 180MHz, this delay needed
1932 to be *at least* 15,000 usec before a Windows Server 2003
1933 DHCP server would reply 100% of the time. I recommend at
1934 least 50,000 usec to be safe. The alternative is to hope
1935 that one of the retries will be successful but note that
1936 the DHCP timeout and retry process takes a longer than
1939 - Link-local IP address negotiation:
1940 Negotiate with other link-local clients on the local network
1941 for an address that doesn't require explicit configuration.
1942 This is especially useful if a DHCP server cannot be guaranteed
1943 to exist in all environments that the device must operate.
1945 See doc/README.link-local for more information.
1948 CONFIG_CDP_DEVICE_ID
1950 The device id used in CDP trigger frames.
1952 CONFIG_CDP_DEVICE_ID_PREFIX
1954 A two character string which is prefixed to the MAC address
1959 A printf format string which contains the ascii name of
1960 the port. Normally is set to "eth%d" which sets
1961 eth0 for the first Ethernet, eth1 for the second etc.
1963 CONFIG_CDP_CAPABILITIES
1965 A 32bit integer which indicates the device capabilities;
1966 0x00000010 for a normal host which does not forwards.
1970 An ascii string containing the version of the software.
1974 An ascii string containing the name of the platform.
1978 A 32bit integer sent on the trigger.
1980 CONFIG_CDP_POWER_CONSUMPTION
1982 A 16bit integer containing the power consumption of the
1983 device in .1 of milliwatts.
1985 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1987 A byte containing the id of the VLAN.
1989 - Status LED: CONFIG_LED_STATUS
1991 Several configurations allow to display the current
1992 status using a LED. For instance, the LED will blink
1993 fast while running U-Boot code, stop blinking as
1994 soon as a reply to a BOOTP request was received, and
1995 start blinking slow once the Linux kernel is running
1996 (supported by a status LED driver in the Linux
1997 kernel). Defining CONFIG_LED_STATUS enables this
2002 CONFIG_LED_STATUS_GPIO
2003 The status LED can be connected to a GPIO pin.
2004 In such cases, the gpio_led driver can be used as a
2005 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2006 to include the gpio_led driver in the U-Boot binary.
2008 CONFIG_GPIO_LED_INVERTED_TABLE
2009 Some GPIO connected LEDs may have inverted polarity in which
2010 case the GPIO high value corresponds to LED off state and
2011 GPIO low value corresponds to LED on state.
2012 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2013 with a list of GPIO LEDs that have inverted polarity.
2015 - CAN Support: CONFIG_CAN_DRIVER
2017 Defining CONFIG_CAN_DRIVER enables CAN driver support
2018 on those systems that support this (optional)
2019 feature, like the TQM8xxL modules.
2021 - I2C Support: CONFIG_SYS_I2C
2023 This enable the NEW i2c subsystem, and will allow you to use
2024 i2c commands at the u-boot command line (as long as you set
2025 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2026 based realtime clock chips or other i2c devices. See
2027 common/cmd_i2c.c for a description of the command line
2030 ported i2c driver to the new framework:
2031 - drivers/i2c/soft_i2c.c:
2032 - activate first bus with CONFIG_SYS_I2C_SOFT define
2033 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2034 for defining speed and slave address
2035 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2036 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2037 for defining speed and slave address
2038 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2039 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2040 for defining speed and slave address
2041 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2042 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2043 for defining speed and slave address
2045 - drivers/i2c/fsl_i2c.c:
2046 - activate i2c driver with CONFIG_SYS_I2C_FSL
2047 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2048 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2049 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2051 - If your board supports a second fsl i2c bus, define
2052 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2053 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2054 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2057 - drivers/i2c/tegra_i2c.c:
2058 - activate this driver with CONFIG_SYS_I2C_TEGRA
2059 - This driver adds 4 i2c buses with a fix speed from
2060 100000 and the slave addr 0!
2062 - drivers/i2c/ppc4xx_i2c.c
2063 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2064 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2065 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2067 - drivers/i2c/i2c_mxc.c
2068 - activate this driver with CONFIG_SYS_I2C_MXC
2069 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2070 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2071 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2072 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2073 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2074 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2075 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2076 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2077 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2078 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2079 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2080 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2081 If those defines are not set, default value is 100000
2082 for speed, and 0 for slave.
2084 - drivers/i2c/rcar_i2c.c:
2085 - activate this driver with CONFIG_SYS_I2C_RCAR
2086 - This driver adds 4 i2c buses
2088 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2089 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2090 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2091 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2092 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2093 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2094 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2095 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2096 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2098 - drivers/i2c/sh_i2c.c:
2099 - activate this driver with CONFIG_SYS_I2C_SH
2100 - This driver adds from 2 to 5 i2c buses
2102 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2103 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2104 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2105 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2106 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2107 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2108 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2109 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2110 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2111 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2112 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2114 - drivers/i2c/omap24xx_i2c.c
2115 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2116 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2117 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2118 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2119 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2120 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2121 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2122 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2123 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2124 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2125 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2127 - drivers/i2c/zynq_i2c.c
2128 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2129 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2130 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2132 - drivers/i2c/s3c24x0_i2c.c:
2133 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2134 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2135 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2136 with a fix speed from 100000 and the slave addr 0!
2138 - drivers/i2c/ihs_i2c.c
2139 - activate this driver with CONFIG_SYS_I2C_IHS
2140 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2141 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2142 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2143 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2144 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2145 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2146 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2147 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2148 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2149 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2150 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2151 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2152 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2153 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2154 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2155 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2156 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2157 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2158 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2159 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2160 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2164 CONFIG_SYS_NUM_I2C_BUSES
2165 Hold the number of i2c buses you want to use.
2167 CONFIG_SYS_I2C_DIRECT_BUS
2168 define this, if you don't use i2c muxes on your hardware.
2169 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2172 CONFIG_SYS_I2C_MAX_HOPS
2173 define how many muxes are maximal consecutively connected
2174 on one i2c bus. If you not use i2c muxes, omit this
2177 CONFIG_SYS_I2C_BUSES
2178 hold a list of buses you want to use, only used if
2179 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2180 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2181 CONFIG_SYS_NUM_I2C_BUSES = 9:
2183 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2184 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2185 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2186 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2187 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2188 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2189 {1, {I2C_NULL_HOP}}, \
2190 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2191 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2195 bus 0 on adapter 0 without a mux
2196 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2197 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2198 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2199 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2200 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2201 bus 6 on adapter 1 without a mux
2202 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2203 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2205 If you do not have i2c muxes on your board, omit this define.
2209 - Legacy I2C Support: CONFIG_SOFT_I2C
2211 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2212 provides the following compelling advantages:
2214 - more than one i2c adapter is usable
2215 - approved multibus support
2216 - better i2c mux support
2218 ** CONFIG_SOFT_I2C is now being removed **
2220 With CONFIG_SOFT_I2C you will need to define
2221 CONFIG_SYS_I2C_SPEED to be the frequency (in Hz) at which you
2222 wish your i2c bus to run and CONFIG_SYS_I2C_SLAVE to be the
2223 address of this node (ie the CPU's i2c node address).
2225 Now, the u-boot i2c code for the mpc8xx
2226 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2227 and so its address should therefore be cleared to 0 (See,
2228 eg, MPC823e User's Manual p.16-473). So, set
2229 CONFIG_SYS_I2C_SLAVE to 0.
2231 When a board is reset during an i2c bus transfer
2232 chips might think that the current transfer is still
2233 in progress. Reset the slave devices by sending start
2234 commands until the slave device responds.
2236 That's all that's required for CONFIG_HARD_I2C.
2238 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2239 then the following macros need to be defined (examples are
2240 from include/configs/lwmon.h):
2244 (Optional). Any commands necessary to enable the I2C
2245 controller or configure ports.
2247 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2251 (Only for MPC8260 CPU). The I/O port to use (the code
2252 assumes both bits are on the same port). Valid values
2253 are 0..3 for ports A..D.
2257 The code necessary to make the I2C data line active
2258 (driven). If the data line is open collector, this
2261 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2265 The code necessary to make the I2C data line tri-stated
2266 (inactive). If the data line is open collector, this
2269 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2273 Code that returns true if the I2C data line is high,
2276 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2280 If <bit> is true, sets the I2C data line high. If it
2281 is false, it clears it (low).
2283 eg: #define I2C_SDA(bit) \
2284 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2285 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2289 If <bit> is true, sets the I2C clock line high. If it
2290 is false, it clears it (low).
2292 eg: #define I2C_SCL(bit) \
2293 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2294 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2298 This delay is invoked four times per clock cycle so this
2299 controls the rate of data transfer. The data rate thus
2300 is 1 / (I2C_DELAY * 4). Often defined to be something
2303 #define I2C_DELAY udelay(2)
2305 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2307 If your arch supports the generic GPIO framework (asm/gpio.h),
2308 then you may alternatively define the two GPIOs that are to be
2309 used as SCL / SDA. Any of the previous I2C_xxx macros will
2310 have GPIO-based defaults assigned to them as appropriate.
2312 You should define these to the GPIO value as given directly to
2313 the generic GPIO functions.
2315 CONFIG_SYS_I2C_INIT_BOARD
2317 When a board is reset during an i2c bus transfer
2318 chips might think that the current transfer is still
2319 in progress. On some boards it is possible to access
2320 the i2c SCLK line directly, either by using the
2321 processor pin as a GPIO or by having a second pin
2322 connected to the bus. If this option is defined a
2323 custom i2c_init_board() routine in boards/xxx/board.c
2324 is run early in the boot sequence.
2326 CONFIG_SYS_I2C_BOARD_LATE_INIT
2328 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2329 defined a custom i2c_board_late_init() routine in
2330 boards/xxx/board.c is run AFTER the operations in i2c_init()
2331 is completed. This callpoint can be used to unreset i2c bus
2332 using CPU i2c controller register accesses for CPUs whose i2c
2333 controller provide such a method. It is called at the end of
2334 i2c_init() to allow i2c_init operations to setup the i2c bus
2335 controller on the CPU (e.g. setting bus speed & slave address).
2337 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2339 This option enables configuration of bi_iic_fast[] flags
2340 in u-boot bd_info structure based on u-boot environment
2341 variable "i2cfast". (see also i2cfast)
2343 CONFIG_I2C_MULTI_BUS
2345 This option allows the use of multiple I2C buses, each of which
2346 must have a controller. At any point in time, only one bus is
2347 active. To switch to a different bus, use the 'i2c dev' command.
2348 Note that bus numbering is zero-based.
2350 CONFIG_SYS_I2C_NOPROBES
2352 This option specifies a list of I2C devices that will be skipped
2353 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2354 is set, specify a list of bus-device pairs. Otherwise, specify
2355 a 1D array of device addresses
2358 #undef CONFIG_I2C_MULTI_BUS
2359 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2361 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2363 #define CONFIG_I2C_MULTI_BUS
2364 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2366 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2368 CONFIG_SYS_SPD_BUS_NUM
2370 If defined, then this indicates the I2C bus number for DDR SPD.
2371 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2373 CONFIG_SYS_RTC_BUS_NUM
2375 If defined, then this indicates the I2C bus number for the RTC.
2376 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2378 CONFIG_SYS_DTT_BUS_NUM
2380 If defined, then this indicates the I2C bus number for the DTT.
2381 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2383 CONFIG_SYS_I2C_DTT_ADDR:
2385 If defined, specifies the I2C address of the DTT device.
2386 If not defined, then U-Boot uses predefined value for
2387 specified DTT device.
2389 CONFIG_SOFT_I2C_READ_REPEATED_START
2391 defining this will force the i2c_read() function in
2392 the soft_i2c driver to perform an I2C repeated start
2393 between writing the address pointer and reading the
2394 data. If this define is omitted the default behaviour
2395 of doing a stop-start sequence will be used. Most I2C
2396 devices can use either method, but some require one or
2399 - SPI Support: CONFIG_SPI
2401 Enables SPI driver (so far only tested with
2402 SPI EEPROM, also an instance works with Crystal A/D and
2403 D/As on the SACSng board)
2407 Enables the driver for SPI controller on SuperH. Currently
2408 only SH7757 is supported.
2412 Enables a software (bit-bang) SPI driver rather than
2413 using hardware support. This is a general purpose
2414 driver that only requires three general I/O port pins
2415 (two outputs, one input) to function. If this is
2416 defined, the board configuration must define several
2417 SPI configuration items (port pins to use, etc). For
2418 an example, see include/configs/sacsng.h.
2422 Enables a hardware SPI driver for general-purpose reads
2423 and writes. As with CONFIG_SOFT_SPI, the board configuration
2424 must define a list of chip-select function pointers.
2425 Currently supported on some MPC8xxx processors. For an
2426 example, see include/configs/mpc8349emds.h.
2430 Enables the driver for the SPI controllers on i.MX and MXC
2431 SoCs. Currently i.MX31/35/51 are supported.
2433 CONFIG_SYS_SPI_MXC_WAIT
2434 Timeout for waiting until spi transfer completed.
2435 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2437 - FPGA Support: CONFIG_FPGA
2439 Enables FPGA subsystem.
2441 CONFIG_FPGA_<vendor>
2443 Enables support for specific chip vendors.
2446 CONFIG_FPGA_<family>
2448 Enables support for FPGA family.
2449 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2453 Specify the number of FPGA devices to support.
2455 CONFIG_CMD_FPGA_LOADMK
2457 Enable support for fpga loadmk command
2459 CONFIG_CMD_FPGA_LOADP
2461 Enable support for fpga loadp command - load partial bitstream
2463 CONFIG_CMD_FPGA_LOADBP
2465 Enable support for fpga loadbp command - load partial bitstream
2468 CONFIG_SYS_FPGA_PROG_FEEDBACK
2470 Enable printing of hash marks during FPGA configuration.
2472 CONFIG_SYS_FPGA_CHECK_BUSY
2474 Enable checks on FPGA configuration interface busy
2475 status by the configuration function. This option
2476 will require a board or device specific function to
2481 If defined, a function that provides delays in the FPGA
2482 configuration driver.
2484 CONFIG_SYS_FPGA_CHECK_CTRLC
2485 Allow Control-C to interrupt FPGA configuration
2487 CONFIG_SYS_FPGA_CHECK_ERROR
2489 Check for configuration errors during FPGA bitfile
2490 loading. For example, abort during Virtex II
2491 configuration if the INIT_B line goes low (which
2492 indicated a CRC error).
2494 CONFIG_SYS_FPGA_WAIT_INIT
2496 Maximum time to wait for the INIT_B line to de-assert
2497 after PROB_B has been de-asserted during a Virtex II
2498 FPGA configuration sequence. The default time is 500
2501 CONFIG_SYS_FPGA_WAIT_BUSY
2503 Maximum time to wait for BUSY to de-assert during
2504 Virtex II FPGA configuration. The default is 5 ms.
2506 CONFIG_SYS_FPGA_WAIT_CONFIG
2508 Time to wait after FPGA configuration. The default is
2511 - Configuration Management:
2514 Some SoCs need special image types (e.g. U-Boot binary
2515 with a special header) as build targets. By defining
2516 CONFIG_BUILD_TARGET in the SoC / board header, this
2517 special image will be automatically built upon calling
2522 If defined, this string will be added to the U-Boot
2523 version information (U_BOOT_VERSION)
2525 - Vendor Parameter Protection:
2527 U-Boot considers the values of the environment
2528 variables "serial#" (Board Serial Number) and
2529 "ethaddr" (Ethernet Address) to be parameters that
2530 are set once by the board vendor / manufacturer, and
2531 protects these variables from casual modification by
2532 the user. Once set, these variables are read-only,
2533 and write or delete attempts are rejected. You can
2534 change this behaviour:
2536 If CONFIG_ENV_OVERWRITE is #defined in your config
2537 file, the write protection for vendor parameters is
2538 completely disabled. Anybody can change or delete
2541 Alternatively, if you define _both_ an ethaddr in the
2542 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2543 Ethernet address is installed in the environment,
2544 which can be changed exactly ONCE by the user. [The
2545 serial# is unaffected by this, i. e. it remains
2548 The same can be accomplished in a more flexible way
2549 for any variable by configuring the type of access
2550 to allow for those variables in the ".flags" variable
2551 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2556 Define this variable to enable the reservation of
2557 "protected RAM", i. e. RAM which is not overwritten
2558 by U-Boot. Define CONFIG_PRAM to hold the number of
2559 kB you want to reserve for pRAM. You can overwrite
2560 this default value by defining an environment
2561 variable "pram" to the number of kB you want to
2562 reserve. Note that the board info structure will
2563 still show the full amount of RAM. If pRAM is
2564 reserved, a new environment variable "mem" will
2565 automatically be defined to hold the amount of
2566 remaining RAM in a form that can be passed as boot
2567 argument to Linux, for instance like that:
2569 setenv bootargs ... mem=\${mem}
2572 This way you can tell Linux not to use this memory,
2573 either, which results in a memory region that will
2574 not be affected by reboots.
2576 *WARNING* If your board configuration uses automatic
2577 detection of the RAM size, you must make sure that
2578 this memory test is non-destructive. So far, the
2579 following board configurations are known to be
2582 IVMS8, IVML24, SPD8xx, TQM8xxL,
2583 HERMES, IP860, RPXlite, LWMON,
2586 - Access to physical memory region (> 4GB)
2587 Some basic support is provided for operations on memory not
2588 normally accessible to U-Boot - e.g. some architectures
2589 support access to more than 4GB of memory on 32-bit
2590 machines using physical address extension or similar.
2591 Define CONFIG_PHYSMEM to access this basic support, which
2592 currently only supports clearing the memory.
2597 Define this variable to stop the system in case of a
2598 fatal error, so that you have to reset it manually.
2599 This is probably NOT a good idea for an embedded
2600 system where you want the system to reboot
2601 automatically as fast as possible, but it may be
2602 useful during development since you can try to debug
2603 the conditions that lead to the situation.
2605 CONFIG_NET_RETRY_COUNT
2607 This variable defines the number of retries for
2608 network operations like ARP, RARP, TFTP, or BOOTP
2609 before giving up the operation. If not defined, a
2610 default value of 5 is used.
2614 Timeout waiting for an ARP reply in milliseconds.
2618 Timeout in milliseconds used in NFS protocol.
2619 If you encounter "ERROR: Cannot umount" in nfs command,
2620 try longer timeout such as
2621 #define CONFIG_NFS_TIMEOUT 10000UL
2623 - Command Interpreter:
2624 CONFIG_AUTO_COMPLETE
2626 Enable auto completion of commands using TAB.
2628 CONFIG_SYS_PROMPT_HUSH_PS2
2630 This defines the secondary prompt string, which is
2631 printed when the command interpreter needs more input
2632 to complete a command. Usually "> ".
2636 In the current implementation, the local variables
2637 space and global environment variables space are
2638 separated. Local variables are those you define by
2639 simply typing `name=value'. To access a local
2640 variable later on, you have write `$name' or
2641 `${name}'; to execute the contents of a variable
2642 directly type `$name' at the command prompt.
2644 Global environment variables are those you use
2645 setenv/printenv to work with. To run a command stored
2646 in such a variable, you need to use the run command,
2647 and you must not use the '$' sign to access them.
2649 To store commands and special characters in a
2650 variable, please use double quotation marks
2651 surrounding the whole text of the variable, instead
2652 of the backslashes before semicolons and special
2655 - Command Line Editing and History:
2656 CONFIG_CMDLINE_EDITING
2658 Enable editing and History functions for interactive
2659 command line input operations
2661 - Command Line PS1/PS2 support:
2662 CONFIG_CMDLINE_PS_SUPPORT
2664 Enable support for changing the command prompt string
2665 at run-time. Only static string is supported so far.
2666 The string is obtained from environment variables PS1
2669 - Default Environment:
2670 CONFIG_EXTRA_ENV_SETTINGS
2672 Define this to contain any number of null terminated
2673 strings (variable = value pairs) that will be part of
2674 the default environment compiled into the boot image.
2676 For example, place something like this in your
2677 board's config file:
2679 #define CONFIG_EXTRA_ENV_SETTINGS \
2683 Warning: This method is based on knowledge about the
2684 internal format how the environment is stored by the
2685 U-Boot code. This is NOT an official, exported
2686 interface! Although it is unlikely that this format
2687 will change soon, there is no guarantee either.
2688 You better know what you are doing here.
2690 Note: overly (ab)use of the default environment is
2691 discouraged. Make sure to check other ways to preset
2692 the environment like the "source" command or the
2695 CONFIG_ENV_VARS_UBOOT_CONFIG
2697 Define this in order to add variables describing the
2698 U-Boot build configuration to the default environment.
2699 These will be named arch, cpu, board, vendor, and soc.
2701 Enabling this option will cause the following to be defined:
2709 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2711 Define this in order to add variables describing certain
2712 run-time determined information about the hardware to the
2713 environment. These will be named board_name, board_rev.
2715 CONFIG_DELAY_ENVIRONMENT
2717 Normally the environment is loaded when the board is
2718 initialised so that it is available to U-Boot. This inhibits
2719 that so that the environment is not available until
2720 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2721 this is instead controlled by the value of
2722 /config/load-environment.
2724 - DataFlash Support:
2725 CONFIG_HAS_DATAFLASH
2727 Defining this option enables DataFlash features and
2728 allows to read/write in Dataflash via the standard
2731 - Serial Flash support
2734 Defining this option enables SPI flash commands
2735 'sf probe/read/write/erase/update'.
2737 Usage requires an initial 'probe' to define the serial
2738 flash parameters, followed by read/write/erase/update
2741 The following defaults may be provided by the platform
2742 to handle the common case when only a single serial
2743 flash is present on the system.
2745 CONFIG_SF_DEFAULT_BUS Bus identifier
2746 CONFIG_SF_DEFAULT_CS Chip-select
2747 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2748 CONFIG_SF_DEFAULT_SPEED in Hz
2752 Define this option to include a destructive SPI flash
2755 CONFIG_SF_DUAL_FLASH Dual flash memories
2757 Define this option to use dual flash support where two flash
2758 memories can be connected with a given cs line.
2759 Currently Xilinx Zynq qspi supports these type of connections.
2761 - SystemACE Support:
2764 Adding this option adds support for Xilinx SystemACE
2765 chips attached via some sort of local bus. The address
2766 of the chip must also be defined in the
2767 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2769 #define CONFIG_SYSTEMACE
2770 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2772 When SystemACE support is added, the "ace" device type
2773 becomes available to the fat commands, i.e. fatls.
2775 - TFTP Fixed UDP Port:
2778 If this is defined, the environment variable tftpsrcp
2779 is used to supply the TFTP UDP source port value.
2780 If tftpsrcp isn't defined, the normal pseudo-random port
2781 number generator is used.
2783 Also, the environment variable tftpdstp is used to supply
2784 the TFTP UDP destination port value. If tftpdstp isn't
2785 defined, the normal port 69 is used.
2787 The purpose for tftpsrcp is to allow a TFTP server to
2788 blindly start the TFTP transfer using the pre-configured
2789 target IP address and UDP port. This has the effect of
2790 "punching through" the (Windows XP) firewall, allowing
2791 the remainder of the TFTP transfer to proceed normally.
2792 A better solution is to properly configure the firewall,
2793 but sometimes that is not allowed.
2798 This enables a generic 'hash' command which can produce
2799 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2803 Enable the hash verify command (hash -v). This adds to code
2806 CONFIG_SHA1 - This option enables support of hashing using SHA1
2807 algorithm. The hash is calculated in software.
2808 CONFIG_SHA256 - This option enables support of hashing using
2809 SHA256 algorithm. The hash is calculated in software.
2810 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2811 for SHA1/SHA256 hashing.
2812 This affects the 'hash' command and also the
2813 hash_lookup_algo() function.
2814 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2815 hardware-acceleration for SHA1/SHA256 progressive hashing.
2816 Data can be streamed in a block at a time and the hashing
2817 is performed in hardware.
2819 Note: There is also a sha1sum command, which should perhaps
2820 be deprecated in favour of 'hash sha1'.
2822 - Freescale i.MX specific commands:
2823 CONFIG_CMD_HDMIDETECT
2824 This enables 'hdmidet' command which returns true if an
2825 HDMI monitor is detected. This command is i.MX 6 specific.
2827 - bootcount support:
2828 CONFIG_BOOTCOUNT_LIMIT
2830 This enables the bootcounter support, see:
2831 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2834 enable special bootcounter support on at91sam9xe based boards.
2836 enable special bootcounter support on da850 based boards.
2837 CONFIG_BOOTCOUNT_RAM
2838 enable support for the bootcounter in RAM
2839 CONFIG_BOOTCOUNT_I2C
2840 enable support for the bootcounter on an i2c (like RTC) device.
2841 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2842 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2844 CONFIG_BOOTCOUNT_ALEN = address len
2846 - Show boot progress:
2847 CONFIG_SHOW_BOOT_PROGRESS
2849 Defining this option allows to add some board-
2850 specific code (calling a user-provided function
2851 "show_boot_progress(int)") that enables you to show
2852 the system's boot progress on some display (for
2853 example, some LED's) on your board. At the moment,
2854 the following checkpoints are implemented:
2857 Legacy uImage format:
2860 1 common/cmd_bootm.c before attempting to boot an image
2861 -1 common/cmd_bootm.c Image header has bad magic number
2862 2 common/cmd_bootm.c Image header has correct magic number
2863 -2 common/cmd_bootm.c Image header has bad checksum
2864 3 common/cmd_bootm.c Image header has correct checksum
2865 -3 common/cmd_bootm.c Image data has bad checksum
2866 4 common/cmd_bootm.c Image data has correct checksum
2867 -4 common/cmd_bootm.c Image is for unsupported architecture
2868 5 common/cmd_bootm.c Architecture check OK
2869 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2870 6 common/cmd_bootm.c Image Type check OK
2871 -6 common/cmd_bootm.c gunzip uncompression error
2872 -7 common/cmd_bootm.c Unimplemented compression type
2873 7 common/cmd_bootm.c Uncompression OK
2874 8 common/cmd_bootm.c No uncompress/copy overwrite error
2875 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2877 9 common/image.c Start initial ramdisk verification
2878 -10 common/image.c Ramdisk header has bad magic number
2879 -11 common/image.c Ramdisk header has bad checksum
2880 10 common/image.c Ramdisk header is OK
2881 -12 common/image.c Ramdisk data has bad checksum
2882 11 common/image.c Ramdisk data has correct checksum
2883 12 common/image.c Ramdisk verification complete, start loading
2884 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2885 13 common/image.c Start multifile image verification
2886 14 common/image.c No initial ramdisk, no multifile, continue.
2888 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2890 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2891 -31 post/post.c POST test failed, detected by post_output_backlog()
2892 -32 post/post.c POST test failed, detected by post_run_single()
2894 34 common/cmd_doc.c before loading a Image from a DOC device
2895 -35 common/cmd_doc.c Bad usage of "doc" command
2896 35 common/cmd_doc.c correct usage of "doc" command
2897 -36 common/cmd_doc.c No boot device
2898 36 common/cmd_doc.c correct boot device
2899 -37 common/cmd_doc.c Unknown Chip ID on boot device
2900 37 common/cmd_doc.c correct chip ID found, device available
2901 -38 common/cmd_doc.c Read Error on boot device
2902 38 common/cmd_doc.c reading Image header from DOC device OK
2903 -39 common/cmd_doc.c Image header has bad magic number
2904 39 common/cmd_doc.c Image header has correct magic number
2905 -40 common/cmd_doc.c Error reading Image from DOC device
2906 40 common/cmd_doc.c Image header has correct magic number
2907 41 common/cmd_ide.c before loading a Image from a IDE device
2908 -42 common/cmd_ide.c Bad usage of "ide" command
2909 42 common/cmd_ide.c correct usage of "ide" command
2910 -43 common/cmd_ide.c No boot device
2911 43 common/cmd_ide.c boot device found
2912 -44 common/cmd_ide.c Device not available
2913 44 common/cmd_ide.c Device available
2914 -45 common/cmd_ide.c wrong partition selected
2915 45 common/cmd_ide.c partition selected
2916 -46 common/cmd_ide.c Unknown partition table
2917 46 common/cmd_ide.c valid partition table found
2918 -47 common/cmd_ide.c Invalid partition type
2919 47 common/cmd_ide.c correct partition type
2920 -48 common/cmd_ide.c Error reading Image Header on boot device
2921 48 common/cmd_ide.c reading Image Header from IDE device OK
2922 -49 common/cmd_ide.c Image header has bad magic number
2923 49 common/cmd_ide.c Image header has correct magic number
2924 -50 common/cmd_ide.c Image header has bad checksum
2925 50 common/cmd_ide.c Image header has correct checksum
2926 -51 common/cmd_ide.c Error reading Image from IDE device
2927 51 common/cmd_ide.c reading Image from IDE device OK
2928 52 common/cmd_nand.c before loading a Image from a NAND device
2929 -53 common/cmd_nand.c Bad usage of "nand" command
2930 53 common/cmd_nand.c correct usage of "nand" command
2931 -54 common/cmd_nand.c No boot device
2932 54 common/cmd_nand.c boot device found
2933 -55 common/cmd_nand.c Unknown Chip ID on boot device
2934 55 common/cmd_nand.c correct chip ID found, device available
2935 -56 common/cmd_nand.c Error reading Image Header on boot device
2936 56 common/cmd_nand.c reading Image Header from NAND device OK
2937 -57 common/cmd_nand.c Image header has bad magic number
2938 57 common/cmd_nand.c Image header has correct magic number
2939 -58 common/cmd_nand.c Error reading Image from NAND device
2940 58 common/cmd_nand.c reading Image from NAND device OK
2942 -60 common/env_common.c Environment has a bad CRC, using default
2944 64 net/eth.c starting with Ethernet configuration.
2945 -64 net/eth.c no Ethernet found.
2946 65 net/eth.c Ethernet found.
2948 -80 common/cmd_net.c usage wrong
2949 80 common/cmd_net.c before calling net_loop()
2950 -81 common/cmd_net.c some error in net_loop() occurred
2951 81 common/cmd_net.c net_loop() back without error
2952 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2953 82 common/cmd_net.c trying automatic boot
2954 83 common/cmd_net.c running "source" command
2955 -83 common/cmd_net.c some error in automatic boot or "source" command
2956 84 common/cmd_net.c end without errors
2961 100 common/cmd_bootm.c Kernel FIT Image has correct format
2962 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2963 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2964 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2965 102 common/cmd_bootm.c Kernel unit name specified
2966 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2967 103 common/cmd_bootm.c Found configuration node
2968 104 common/cmd_bootm.c Got kernel subimage node offset
2969 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2970 105 common/cmd_bootm.c Kernel subimage hash verification OK
2971 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2972 106 common/cmd_bootm.c Architecture check OK
2973 -106 common/cmd_bootm.c Kernel subimage has wrong type
2974 107 common/cmd_bootm.c Kernel subimage type OK
2975 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2976 108 common/cmd_bootm.c Got kernel subimage data/size
2977 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2978 -109 common/cmd_bootm.c Can't get kernel subimage type
2979 -110 common/cmd_bootm.c Can't get kernel subimage comp
2980 -111 common/cmd_bootm.c Can't get kernel subimage os
2981 -112 common/cmd_bootm.c Can't get kernel subimage load address
2982 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2984 120 common/image.c Start initial ramdisk verification
2985 -120 common/image.c Ramdisk FIT image has incorrect format
2986 121 common/image.c Ramdisk FIT image has correct format
2987 122 common/image.c No ramdisk subimage unit name, using configuration
2988 -122 common/image.c Can't get configuration for ramdisk subimage
2989 123 common/image.c Ramdisk unit name specified
2990 -124 common/image.c Can't get ramdisk subimage node offset
2991 125 common/image.c Got ramdisk subimage node offset
2992 -125 common/image.c Ramdisk subimage hash verification failed
2993 126 common/image.c Ramdisk subimage hash verification OK
2994 -126 common/image.c Ramdisk subimage for unsupported architecture
2995 127 common/image.c Architecture check OK
2996 -127 common/image.c Can't get ramdisk subimage data/size
2997 128 common/image.c Got ramdisk subimage data/size
2998 129 common/image.c Can't get ramdisk load address
2999 -129 common/image.c Got ramdisk load address
3001 -130 common/cmd_doc.c Incorrect FIT image format
3002 131 common/cmd_doc.c FIT image format OK
3004 -140 common/cmd_ide.c Incorrect FIT image format
3005 141 common/cmd_ide.c FIT image format OK
3007 -150 common/cmd_nand.c Incorrect FIT image format
3008 151 common/cmd_nand.c FIT image format OK
3010 - legacy image format:
3011 CONFIG_IMAGE_FORMAT_LEGACY
3012 enables the legacy image format support in U-Boot.
3015 enabled if CONFIG_FIT_SIGNATURE is not defined.
3017 CONFIG_DISABLE_IMAGE_LEGACY
3018 disable the legacy image format
3020 This define is introduced, as the legacy image format is
3021 enabled per default for backward compatibility.
3023 - FIT image support:
3024 CONFIG_FIT_DISABLE_SHA256
3025 Supporting SHA256 hashes has quite an impact on binary size.
3026 For constrained systems sha256 hash support can be disabled
3029 TODO(sjg@chromium.org): Adjust this option to be positive,
3030 and move it to Kconfig
3032 - Standalone program support:
3033 CONFIG_STANDALONE_LOAD_ADDR
3035 This option defines a board specific value for the
3036 address where standalone program gets loaded, thus
3037 overwriting the architecture dependent default
3040 - Frame Buffer Address:
3043 Define CONFIG_FB_ADDR if you want to use specific
3044 address for frame buffer. This is typically the case
3045 when using a graphics controller has separate video
3046 memory. U-Boot will then place the frame buffer at
3047 the given address instead of dynamically reserving it
3048 in system RAM by calling lcd_setmem(), which grabs
3049 the memory for the frame buffer depending on the
3050 configured panel size.
3052 Please see board_init_f function.
3054 - Automatic software updates via TFTP server
3056 CONFIG_UPDATE_TFTP_CNT_MAX
3057 CONFIG_UPDATE_TFTP_MSEC_MAX
3059 These options enable and control the auto-update feature;
3060 for a more detailed description refer to doc/README.update.
3062 - MTD Support (mtdparts command, UBI support)
3065 Adds the MTD device infrastructure from the Linux kernel.
3066 Needed for mtdparts command support.
3068 CONFIG_MTD_PARTITIONS
3070 Adds the MTD partitioning infrastructure from the Linux
3071 kernel. Needed for UBI support.
3076 Adds commands for interacting with MTD partitions formatted
3077 with the UBI flash translation layer
3079 Requires also defining CONFIG_RBTREE
3081 CONFIG_UBI_SILENCE_MSG
3083 Make the verbose messages from UBI stop printing. This leaves
3084 warnings and errors enabled.
3087 CONFIG_MTD_UBI_WL_THRESHOLD
3088 This parameter defines the maximum difference between the highest
3089 erase counter value and the lowest erase counter value of eraseblocks
3090 of UBI devices. When this threshold is exceeded, UBI starts performing
3091 wear leveling by means of moving data from eraseblock with low erase
3092 counter to eraseblocks with high erase counter.
3094 The default value should be OK for SLC NAND flashes, NOR flashes and
3095 other flashes which have eraseblock life-cycle 100000 or more.
3096 However, in case of MLC NAND flashes which typically have eraseblock
3097 life-cycle less than 10000, the threshold should be lessened (e.g.,
3098 to 128 or 256, although it does not have to be power of 2).
3102 CONFIG_MTD_UBI_BEB_LIMIT
3103 This option specifies the maximum bad physical eraseblocks UBI
3104 expects on the MTD device (per 1024 eraseblocks). If the
3105 underlying flash does not admit of bad eraseblocks (e.g. NOR
3106 flash), this value is ignored.
3108 NAND datasheets often specify the minimum and maximum NVM
3109 (Number of Valid Blocks) for the flashes' endurance lifetime.
3110 The maximum expected bad eraseblocks per 1024 eraseblocks
3111 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3112 which gives 20 for most NANDs (MaxNVB is basically the total
3113 count of eraseblocks on the chip).
3115 To put it differently, if this value is 20, UBI will try to
3116 reserve about 1.9% of physical eraseblocks for bad blocks
3117 handling. And that will be 1.9% of eraseblocks on the entire
3118 NAND chip, not just the MTD partition UBI attaches. This means
3119 that if you have, say, a NAND flash chip admits maximum 40 bad
3120 eraseblocks, and it is split on two MTD partitions of the same
3121 size, UBI will reserve 40 eraseblocks when attaching a
3126 CONFIG_MTD_UBI_FASTMAP
3127 Fastmap is a mechanism which allows attaching an UBI device
3128 in nearly constant time. Instead of scanning the whole MTD device it
3129 only has to locate a checkpoint (called fastmap) on the device.
3130 The on-flash fastmap contains all information needed to attach
3131 the device. Using fastmap makes only sense on large devices where
3132 attaching by scanning takes long. UBI will not automatically install
3133 a fastmap on old images, but you can set the UBI parameter
3134 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3135 that fastmap-enabled images are still usable with UBI implementations
3136 without fastmap support. On typical flash devices the whole fastmap
3137 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3139 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3140 Set this parameter to enable fastmap automatically on images
3144 CONFIG_MTD_UBI_FM_DEBUG
3145 Enable UBI fastmap debug
3151 Adds commands for interacting with UBI volumes formatted as
3152 UBIFS. UBIFS is read-only in u-boot.
3154 Requires UBI support as well as CONFIG_LZO
3156 CONFIG_UBIFS_SILENCE_MSG
3158 Make the verbose messages from UBIFS stop printing. This leaves
3159 warnings and errors enabled.
3163 Enable building of SPL globally.
3166 LDSCRIPT for linking the SPL binary.
3168 CONFIG_SPL_MAX_FOOTPRINT
3169 Maximum size in memory allocated to the SPL, BSS included.
3170 When defined, the linker checks that the actual memory
3171 used by SPL from _start to __bss_end does not exceed it.
3172 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3173 must not be both defined at the same time.
3176 Maximum size of the SPL image (text, data, rodata, and
3177 linker lists sections), BSS excluded.
3178 When defined, the linker checks that the actual size does
3181 CONFIG_SPL_TEXT_BASE
3182 TEXT_BASE for linking the SPL binary.
3184 CONFIG_SPL_RELOC_TEXT_BASE
3185 Address to relocate to. If unspecified, this is equal to
3186 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3188 CONFIG_SPL_BSS_START_ADDR
3189 Link address for the BSS within the SPL binary.
3191 CONFIG_SPL_BSS_MAX_SIZE
3192 Maximum size in memory allocated to the SPL BSS.
3193 When defined, the linker checks that the actual memory used
3194 by SPL from __bss_start to __bss_end does not exceed it.
3195 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3196 must not be both defined at the same time.
3199 Adress of the start of the stack SPL will use
3201 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3202 When defined, SPL will panic() if the image it has
3203 loaded does not have a signature.
3204 Defining this is useful when code which loads images
3205 in SPL cannot guarantee that absolutely all read errors
3207 An example is the LPC32XX MLC NAND driver, which will
3208 consider that a completely unreadable NAND block is bad,
3209 and thus should be skipped silently.
3211 CONFIG_SPL_RELOC_STACK
3212 Adress of the start of the stack SPL will use after
3213 relocation. If unspecified, this is equal to
3216 CONFIG_SYS_SPL_MALLOC_START
3217 Starting address of the malloc pool used in SPL.
3218 When this option is set the full malloc is used in SPL and
3219 it is set up by spl_init() and before that, the simple malloc()
3220 can be used if CONFIG_SYS_MALLOC_F is defined.
3222 CONFIG_SYS_SPL_MALLOC_SIZE
3223 The size of the malloc pool used in SPL.
3225 CONFIG_SPL_FRAMEWORK
3226 Enable the SPL framework under common/. This framework
3227 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3228 NAND loading of the Linux Kernel.
3231 Enable booting directly to an OS from SPL.
3232 See also: doc/README.falcon
3234 CONFIG_SPL_DISPLAY_PRINT
3235 For ARM, enable an optional function to print more information
3236 about the running system.
3238 CONFIG_SPL_INIT_MINIMAL
3239 Arch init code should be built for a very small image
3241 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3242 Partition on the MMC to load U-Boot from when the MMC is being
3245 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3246 Sector to load kernel uImage from when MMC is being
3247 used in raw mode (for Falcon mode)
3249 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3250 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3251 Sector and number of sectors to load kernel argument
3252 parameters from when MMC is being used in raw mode
3255 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3256 Partition on the MMC to load U-Boot from when the MMC is being
3259 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3260 Filename to read to load U-Boot when reading from filesystem
3262 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3263 Filename to read to load kernel uImage when reading
3264 from filesystem (for Falcon mode)
3266 CONFIG_SPL_FS_LOAD_ARGS_NAME
3267 Filename to read to load kernel argument parameters
3268 when reading from filesystem (for Falcon mode)
3270 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3271 Set this for NAND SPL on PPC mpc83xx targets, so that
3272 start.S waits for the rest of the SPL to load before
3273 continuing (the hardware starts execution after just
3274 loading the first page rather than the full 4K).
3276 CONFIG_SPL_SKIP_RELOCATE
3277 Avoid SPL relocation
3279 CONFIG_SPL_NAND_BASE
3280 Include nand_base.c in the SPL. Requires
3281 CONFIG_SPL_NAND_DRIVERS.
3283 CONFIG_SPL_NAND_DRIVERS
3284 SPL uses normal NAND drivers, not minimal drivers.
3287 Include standard software ECC in the SPL
3289 CONFIG_SPL_NAND_SIMPLE
3290 Support for NAND boot using simple NAND drivers that
3291 expose the cmd_ctrl() interface.
3294 Support for a lightweight UBI (fastmap) scanner and
3297 CONFIG_SPL_NAND_RAW_ONLY
3298 Support to boot only raw u-boot.bin images. Use this only
3299 if you need to save space.
3301 CONFIG_SPL_COMMON_INIT_DDR
3302 Set for common ddr init with serial presence detect in
3305 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3306 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3307 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3308 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3309 CONFIG_SYS_NAND_ECCBYTES
3310 Defines the size and behavior of the NAND that SPL uses
3313 CONFIG_SPL_NAND_BOOT
3314 Add support NAND boot
3316 CONFIG_SYS_NAND_U_BOOT_OFFS
3317 Location in NAND to read U-Boot from
3319 CONFIG_SYS_NAND_U_BOOT_DST
3320 Location in memory to load U-Boot to
3322 CONFIG_SYS_NAND_U_BOOT_SIZE
3323 Size of image to load
3325 CONFIG_SYS_NAND_U_BOOT_START
3326 Entry point in loaded image to jump to
3328 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3329 Define this if you need to first read the OOB and then the
3330 data. This is used, for example, on davinci platforms.
3332 CONFIG_SPL_OMAP3_ID_NAND
3333 Support for an OMAP3-specific set of functions to return the
3334 ID and MFR of the first attached NAND chip, if present.
3336 CONFIG_SPL_RAM_DEVICE
3337 Support for running image already present in ram, in SPL binary
3340 Image offset to which the SPL should be padded before appending
3341 the SPL payload. By default, this is defined as
3342 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3343 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3344 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3347 Final target image containing SPL and payload. Some SPLs
3348 use an arch-specific makefile fragment instead, for
3349 example if more than one image needs to be produced.
3351 CONFIG_FIT_SPL_PRINT
3352 Printing information about a FIT image adds quite a bit of
3353 code to SPL. So this is normally disabled in SPL. Use this
3354 option to re-enable it. This will affect the output of the
3355 bootm command when booting a FIT image.
3359 Enable building of TPL globally.
3362 Image offset to which the TPL should be padded before appending
3363 the TPL payload. By default, this is defined as
3364 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3365 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3366 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3368 - Interrupt support (PPC):
3370 There are common interrupt_init() and timer_interrupt()
3371 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3372 for CPU specific initialization. interrupt_init_cpu()
3373 should set decrementer_count to appropriate value. If
3374 CPU resets decrementer automatically after interrupt
3375 (ppc4xx) it should set decrementer_count to zero.
3376 timer_interrupt() calls timer_interrupt_cpu() for CPU
3377 specific handling. If board has watchdog / status_led
3378 / other_activity_monitor it works automatically from
3379 general timer_interrupt().
3382 Board initialization settings:
3383 ------------------------------
3385 During Initialization u-boot calls a number of board specific functions
3386 to allow the preparation of board specific prerequisites, e.g. pin setup
3387 before drivers are initialized. To enable these callbacks the
3388 following configuration macros have to be defined. Currently this is
3389 architecture specific, so please check arch/your_architecture/lib/board.c
3390 typically in board_init_f() and board_init_r().
3392 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3393 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3394 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3395 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3397 Configuration Settings:
3398 -----------------------
3400 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3401 Optionally it can be defined to support 64-bit memory commands.
3403 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3404 undefine this when you're short of memory.
3406 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3407 width of the commands listed in the 'help' command output.
3409 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3410 prompt for user input.
3412 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3414 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3416 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3418 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3419 the application (usually a Linux kernel) when it is
3422 - CONFIG_SYS_BAUDRATE_TABLE:
3423 List of legal baudrate settings for this board.
3425 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3426 Begin and End addresses of the area used by the
3429 - CONFIG_SYS_ALT_MEMTEST:
3430 Enable an alternate, more extensive memory test.
3432 - CONFIG_SYS_MEMTEST_SCRATCH:
3433 Scratch address used by the alternate memory test
3434 You only need to set this if address zero isn't writeable
3436 - CONFIG_SYS_MEM_RESERVE_SECURE
3437 Only implemented for ARMv8 for now.
3438 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3439 is substracted from total RAM and won't be reported to OS.
3440 This memory can be used as secure memory. A variable
3441 gd->arch.secure_ram is used to track the location. In systems
3442 the RAM base is not zero, or RAM is divided into banks,
3443 this variable needs to be recalcuated to get the address.
3445 - CONFIG_SYS_MEM_TOP_HIDE:
3446 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3447 this specified memory area will get subtracted from the top
3448 (end) of RAM and won't get "touched" at all by U-Boot. By
3449 fixing up gd->ram_size the Linux kernel should gets passed
3450 the now "corrected" memory size and won't touch it either.
3451 This should work for arch/ppc and arch/powerpc. Only Linux
3452 board ports in arch/powerpc with bootwrapper support that
3453 recalculate the memory size from the SDRAM controller setup
3454 will have to get fixed in Linux additionally.
3456 This option can be used as a workaround for the 440EPx/GRx
3457 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3460 WARNING: Please make sure that this value is a multiple of
3461 the Linux page size (normally 4k). If this is not the case,
3462 then the end address of the Linux memory will be located at a
3463 non page size aligned address and this could cause major
3466 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3467 Enable temporary baudrate change while serial download
3469 - CONFIG_SYS_SDRAM_BASE:
3470 Physical start address of SDRAM. _Must_ be 0 here.
3472 - CONFIG_SYS_FLASH_BASE:
3473 Physical start address of Flash memory.
3475 - CONFIG_SYS_MONITOR_BASE:
3476 Physical start address of boot monitor code (set by
3477 make config files to be same as the text base address
3478 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3479 CONFIG_SYS_FLASH_BASE when booting from flash.
3481 - CONFIG_SYS_MONITOR_LEN:
3482 Size of memory reserved for monitor code, used to
3483 determine _at_compile_time_ (!) if the environment is
3484 embedded within the U-Boot image, or in a separate
3487 - CONFIG_SYS_MALLOC_LEN:
3488 Size of DRAM reserved for malloc() use.
3490 - CONFIG_SYS_MALLOC_F_LEN
3491 Size of the malloc() pool for use before relocation. If
3492 this is defined, then a very simple malloc() implementation
3493 will become available before relocation. The address is just
3494 below the global data, and the stack is moved down to make
3497 This feature allocates regions with increasing addresses
3498 within the region. calloc() is supported, but realloc()
3499 is not available. free() is supported but does nothing.
3500 The memory will be freed (or in fact just forgotten) when
3501 U-Boot relocates itself.
3503 - CONFIG_SYS_MALLOC_SIMPLE
3504 Provides a simple and small malloc() and calloc() for those
3505 boards which do not use the full malloc in SPL (which is
3506 enabled with CONFIG_SYS_SPL_MALLOC_START).
3508 - CONFIG_SYS_NONCACHED_MEMORY:
3509 Size of non-cached memory area. This area of memory will be
3510 typically located right below the malloc() area and mapped
3511 uncached in the MMU. This is useful for drivers that would
3512 otherwise require a lot of explicit cache maintenance. For
3513 some drivers it's also impossible to properly maintain the
3514 cache. For example if the regions that need to be flushed
3515 are not a multiple of the cache-line size, *and* padding
3516 cannot be allocated between the regions to align them (i.e.
3517 if the HW requires a contiguous array of regions, and the
3518 size of each region is not cache-aligned), then a flush of
3519 one region may result in overwriting data that hardware has
3520 written to another region in the same cache-line. This can
3521 happen for example in network drivers where descriptors for
3522 buffers are typically smaller than the CPU cache-line (e.g.
3523 16 bytes vs. 32 or 64 bytes).
3525 Non-cached memory is only supported on 32-bit ARM at present.
3527 - CONFIG_SYS_BOOTM_LEN:
3528 Normally compressed uImages are limited to an
3529 uncompressed size of 8 MBytes. If this is not enough,
3530 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3531 to adjust this setting to your needs.
3533 - CONFIG_SYS_BOOTMAPSZ:
3534 Maximum size of memory mapped by the startup code of
3535 the Linux kernel; all data that must be processed by
3536 the Linux kernel (bd_info, boot arguments, FDT blob if
3537 used) must be put below this limit, unless "bootm_low"
3538 environment variable is defined and non-zero. In such case
3539 all data for the Linux kernel must be between "bootm_low"
3540 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3541 variable "bootm_mapsize" will override the value of
3542 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3543 then the value in "bootm_size" will be used instead.
3545 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3546 Enable initrd_high functionality. If defined then the
3547 initrd_high feature is enabled and the bootm ramdisk subcommand
3550 - CONFIG_SYS_BOOT_GET_CMDLINE:
3551 Enables allocating and saving kernel cmdline in space between
3552 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3554 - CONFIG_SYS_BOOT_GET_KBD:
3555 Enables allocating and saving a kernel copy of the bd_info in
3556 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3558 - CONFIG_SYS_MAX_FLASH_BANKS:
3559 Max number of Flash memory banks
3561 - CONFIG_SYS_MAX_FLASH_SECT:
3562 Max number of sectors on a Flash chip
3564 - CONFIG_SYS_FLASH_ERASE_TOUT:
3565 Timeout for Flash erase operations (in ms)
3567 - CONFIG_SYS_FLASH_WRITE_TOUT:
3568 Timeout for Flash write operations (in ms)
3570 - CONFIG_SYS_FLASH_LOCK_TOUT
3571 Timeout for Flash set sector lock bit operation (in ms)
3573 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3574 Timeout for Flash clear lock bits operation (in ms)
3576 - CONFIG_SYS_FLASH_PROTECTION
3577 If defined, hardware flash sectors protection is used
3578 instead of U-Boot software protection.
3580 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3582 Enable TFTP transfers directly to flash memory;
3583 without this option such a download has to be
3584 performed in two steps: (1) download to RAM, and (2)
3585 copy from RAM to flash.
3587 The two-step approach is usually more reliable, since
3588 you can check if the download worked before you erase
3589 the flash, but in some situations (when system RAM is
3590 too limited to allow for a temporary copy of the
3591 downloaded image) this option may be very useful.
3593 - CONFIG_SYS_FLASH_CFI:
3594 Define if the flash driver uses extra elements in the
3595 common flash structure for storing flash geometry.
3597 - CONFIG_FLASH_CFI_DRIVER
3598 This option also enables the building of the cfi_flash driver
3599 in the drivers directory
3601 - CONFIG_FLASH_CFI_MTD
3602 This option enables the building of the cfi_mtd driver
3603 in the drivers directory. The driver exports CFI flash
3606 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3607 Use buffered writes to flash.
3609 - CONFIG_FLASH_SPANSION_S29WS_N
3610 s29ws-n MirrorBit flash has non-standard addresses for buffered
3613 - CONFIG_SYS_FLASH_QUIET_TEST
3614 If this option is defined, the common CFI flash doesn't
3615 print it's warning upon not recognized FLASH banks. This
3616 is useful, if some of the configured banks are only
3617 optionally available.
3619 - CONFIG_FLASH_SHOW_PROGRESS
3620 If defined (must be an integer), print out countdown
3621 digits and dots. Recommended value: 45 (9..1) for 80
3622 column displays, 15 (3..1) for 40 column displays.
3624 - CONFIG_FLASH_VERIFY
3625 If defined, the content of the flash (destination) is compared
3626 against the source after the write operation. An error message
3627 will be printed when the contents are not identical.
3628 Please note that this option is useless in nearly all cases,
3629 since such flash programming errors usually are detected earlier
3630 while unprotecting/erasing/programming. Please only enable
3631 this option if you really know what you are doing.
3633 - CONFIG_SYS_RX_ETH_BUFFER:
3634 Defines the number of Ethernet receive buffers. On some
3635 Ethernet controllers it is recommended to set this value
3636 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3637 buffers can be full shortly after enabling the interface
3638 on high Ethernet traffic.
3639 Defaults to 4 if not defined.
3641 - CONFIG_ENV_MAX_ENTRIES
3643 Maximum number of entries in the hash table that is used
3644 internally to store the environment settings. The default
3645 setting is supposed to be generous and should work in most
3646 cases. This setting can be used to tune behaviour; see
3647 lib/hashtable.c for details.
3649 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3650 - CONFIG_ENV_FLAGS_LIST_STATIC
3651 Enable validation of the values given to environment variables when
3652 calling env set. Variables can be restricted to only decimal,
3653 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3654 the variables can also be restricted to IP address or MAC address.
3656 The format of the list is:
3657 type_attribute = [s|d|x|b|i|m]
3658 access_attribute = [a|r|o|c]
3659 attributes = type_attribute[access_attribute]
3660 entry = variable_name[:attributes]
3663 The type attributes are:
3664 s - String (default)
3667 b - Boolean ([1yYtT|0nNfF])
3671 The access attributes are:
3677 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3678 Define this to a list (string) to define the ".flags"
3679 environment variable in the default or embedded environment.
3681 - CONFIG_ENV_FLAGS_LIST_STATIC
3682 Define this to a list (string) to define validation that
3683 should be done if an entry is not found in the ".flags"
3684 environment variable. To override a setting in the static
3685 list, simply add an entry for the same variable name to the
3688 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3689 regular expression. This allows multiple variables to define the same
3690 flags without explicitly listing them for each variable.
3692 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3693 If defined, don't allow the -f switch to env set override variable
3696 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3697 This is set by OMAP boards for the max time that reset should
3698 be asserted. See doc/README.omap-reset-time for details on how
3699 the value can be calculated on a given board.
3702 If stdint.h is available with your toolchain you can define this
3703 option to enable it. You can provide option 'USE_STDINT=1' when
3704 building U-Boot to enable this.
3706 The following definitions that deal with the placement and management
3707 of environment data (variable area); in general, we support the
3708 following configurations:
3710 - CONFIG_BUILD_ENVCRC:
3712 Builds up envcrc with the target environment so that external utils
3713 may easily extract it and embed it in final U-Boot images.
3715 - CONFIG_ENV_IS_IN_FLASH:
3717 Define this if the environment is in flash memory.
3719 a) The environment occupies one whole flash sector, which is
3720 "embedded" in the text segment with the U-Boot code. This
3721 happens usually with "bottom boot sector" or "top boot
3722 sector" type flash chips, which have several smaller
3723 sectors at the start or the end. For instance, such a
3724 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3725 such a case you would place the environment in one of the
3726 4 kB sectors - with U-Boot code before and after it. With
3727 "top boot sector" type flash chips, you would put the
3728 environment in one of the last sectors, leaving a gap
3729 between U-Boot and the environment.
3731 - CONFIG_ENV_OFFSET:
3733 Offset of environment data (variable area) to the
3734 beginning of flash memory; for instance, with bottom boot
3735 type flash chips the second sector can be used: the offset
3736 for this sector is given here.
3738 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3742 This is just another way to specify the start address of
3743 the flash sector containing the environment (instead of
3746 - CONFIG_ENV_SECT_SIZE:
3748 Size of the sector containing the environment.
3751 b) Sometimes flash chips have few, equal sized, BIG sectors.
3752 In such a case you don't want to spend a whole sector for
3757 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3758 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3759 of this flash sector for the environment. This saves
3760 memory for the RAM copy of the environment.
3762 It may also save flash memory if you decide to use this
3763 when your environment is "embedded" within U-Boot code,
3764 since then the remainder of the flash sector could be used
3765 for U-Boot code. It should be pointed out that this is
3766 STRONGLY DISCOURAGED from a robustness point of view:
3767 updating the environment in flash makes it always
3768 necessary to erase the WHOLE sector. If something goes
3769 wrong before the contents has been restored from a copy in
3770 RAM, your target system will be dead.
3772 - CONFIG_ENV_ADDR_REDUND
3773 CONFIG_ENV_SIZE_REDUND
3775 These settings describe a second storage area used to hold
3776 a redundant copy of the environment data, so that there is
3777 a valid backup copy in case there is a power failure during
3778 a "saveenv" operation.
3780 BE CAREFUL! Any changes to the flash layout, and some changes to the
3781 source code will make it necessary to adapt <board>/u-boot.lds*
3785 - CONFIG_ENV_IS_IN_NVRAM:
3787 Define this if you have some non-volatile memory device
3788 (NVRAM, battery buffered SRAM) which you want to use for the
3794 These two #defines are used to determine the memory area you
3795 want to use for environment. It is assumed that this memory
3796 can just be read and written to, without any special
3799 BE CAREFUL! The first access to the environment happens quite early
3800 in U-Boot initialization (when we try to get the setting of for the
3801 console baudrate). You *MUST* have mapped your NVRAM area then, or
3804 Please note that even with NVRAM we still use a copy of the
3805 environment in RAM: we could work on NVRAM directly, but we want to
3806 keep settings there always unmodified except somebody uses "saveenv"
3807 to save the current settings.
3810 - CONFIG_ENV_IS_IN_EEPROM:
3812 Use this if you have an EEPROM or similar serial access
3813 device and a driver for it.
3815 - CONFIG_ENV_OFFSET:
3818 These two #defines specify the offset and size of the
3819 environment area within the total memory of your EEPROM.
3821 - CONFIG_SYS_I2C_EEPROM_ADDR:
3822 If defined, specified the chip address of the EEPROM device.
3823 The default address is zero.
3825 - CONFIG_SYS_I2C_EEPROM_BUS:
3826 If defined, specified the i2c bus of the EEPROM device.
3828 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3829 If defined, the number of bits used to address bytes in a
3830 single page in the EEPROM device. A 64 byte page, for example
3831 would require six bits.
3833 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3834 If defined, the number of milliseconds to delay between
3835 page writes. The default is zero milliseconds.
3837 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3838 The length in bytes of the EEPROM memory array address. Note
3839 that this is NOT the chip address length!
3841 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3842 EEPROM chips that implement "address overflow" are ones
3843 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3844 address and the extra bits end up in the "chip address" bit
3845 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3848 Note that we consider the length of the address field to
3849 still be one byte because the extra address bits are hidden
3850 in the chip address.
3852 - CONFIG_SYS_EEPROM_SIZE:
3853 The size in bytes of the EEPROM device.
3855 - CONFIG_ENV_EEPROM_IS_ON_I2C
3856 define this, if you have I2C and SPI activated, and your
3857 EEPROM, which holds the environment, is on the I2C bus.
3859 - CONFIG_I2C_ENV_EEPROM_BUS
3860 if you have an Environment on an EEPROM reached over
3861 I2C muxes, you can define here, how to reach this
3862 EEPROM. For example:
3864 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3866 EEPROM which holds the environment, is reached over
3867 a pca9547 i2c mux with address 0x70, channel 3.
3869 - CONFIG_ENV_IS_IN_DATAFLASH:
3871 Define this if you have a DataFlash memory device which you
3872 want to use for the environment.
3874 - CONFIG_ENV_OFFSET:
3878 These three #defines specify the offset and size of the
3879 environment area within the total memory of your DataFlash placed
3880 at the specified address.
3882 - CONFIG_ENV_IS_IN_SPI_FLASH:
3884 Define this if you have a SPI Flash memory device which you
3885 want to use for the environment.
3887 - CONFIG_ENV_OFFSET:
3890 These two #defines specify the offset and size of the
3891 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3892 aligned to an erase sector boundary.
3894 - CONFIG_ENV_SECT_SIZE:
3896 Define the SPI flash's sector size.
3898 - CONFIG_ENV_OFFSET_REDUND (optional):
3900 This setting describes a second storage area of CONFIG_ENV_SIZE
3901 size used to hold a redundant copy of the environment data, so
3902 that there is a valid backup copy in case there is a power failure
3903 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3904 aligned to an erase sector boundary.
3906 - CONFIG_ENV_SPI_BUS (optional):
3907 - CONFIG_ENV_SPI_CS (optional):
3909 Define the SPI bus and chip select. If not defined they will be 0.
3911 - CONFIG_ENV_SPI_MAX_HZ (optional):
3913 Define the SPI max work clock. If not defined then use 1MHz.
3915 - CONFIG_ENV_SPI_MODE (optional):
3917 Define the SPI work mode. If not defined then use SPI_MODE_3.
3919 - CONFIG_ENV_IS_IN_REMOTE:
3921 Define this if you have a remote memory space which you
3922 want to use for the local device's environment.
3927 These two #defines specify the address and size of the
3928 environment area within the remote memory space. The
3929 local device can get the environment from remote memory
3930 space by SRIO or PCIE links.
3932 BE CAREFUL! For some special cases, the local device can not use
3933 "saveenv" command. For example, the local device will get the
3934 environment stored in a remote NOR flash by SRIO or PCIE link,
3935 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3937 - CONFIG_ENV_IS_IN_NAND:
3939 Define this if you have a NAND device which you want to use
3940 for the environment.
3942 - CONFIG_ENV_OFFSET:
3945 These two #defines specify the offset and size of the environment
3946 area within the first NAND device. CONFIG_ENV_OFFSET must be
3947 aligned to an erase block boundary.
3949 - CONFIG_ENV_OFFSET_REDUND (optional):
3951 This setting describes a second storage area of CONFIG_ENV_SIZE
3952 size used to hold a redundant copy of the environment data, so
3953 that there is a valid backup copy in case there is a power failure
3954 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3955 aligned to an erase block boundary.
3957 - CONFIG_ENV_RANGE (optional):
3959 Specifies the length of the region in which the environment
3960 can be written. This should be a multiple of the NAND device's
3961 block size. Specifying a range with more erase blocks than
3962 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3963 the range to be avoided.
3965 - CONFIG_ENV_OFFSET_OOB (optional):
3967 Enables support for dynamically retrieving the offset of the
3968 environment from block zero's out-of-band data. The
3969 "nand env.oob" command can be used to record this offset.
3970 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3971 using CONFIG_ENV_OFFSET_OOB.
3973 - CONFIG_NAND_ENV_DST
3975 Defines address in RAM to which the nand_spl code should copy the
3976 environment. If redundant environment is used, it will be copied to
3977 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3979 - CONFIG_ENV_IS_IN_UBI:
3981 Define this if you have an UBI volume that you want to use for the
3982 environment. This has the benefit of wear-leveling the environment
3983 accesses, which is important on NAND.
3985 - CONFIG_ENV_UBI_PART:
3987 Define this to a string that is the mtd partition containing the UBI.
3989 - CONFIG_ENV_UBI_VOLUME:
3991 Define this to the name of the volume that you want to store the
3994 - CONFIG_ENV_UBI_VOLUME_REDUND:
3996 Define this to the name of another volume to store a second copy of
3997 the environment in. This will enable redundant environments in UBI.
3998 It is assumed that both volumes are in the same MTD partition.
4000 - CONFIG_UBI_SILENCE_MSG
4001 - CONFIG_UBIFS_SILENCE_MSG
4003 You will probably want to define these to avoid a really noisy system
4004 when storing the env in UBI.
4006 - CONFIG_ENV_IS_IN_FAT:
4007 Define this if you want to use the FAT file system for the environment.
4009 - FAT_ENV_INTERFACE:
4011 Define this to a string that is the name of the block device.
4013 - FAT_ENV_DEVICE_AND_PART:
4015 Define this to a string to specify the partition of the device. It can
4018 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4019 - "D:P": device D partition P. Error occurs if device D has no
4022 - "D" or "D:": device D partition 1 if device D has partition
4023 table, or the whole device D if has no partition
4025 - "D:auto": first partition in device D with bootable flag set.
4026 If none, first valid partition in device D. If no
4027 partition table then means device D.
4031 It's a string of the FAT file name. This file use to store the
4035 This should be defined. Otherwise it cannot save the environment file.
4037 - CONFIG_ENV_IS_IN_MMC:
4039 Define this if you have an MMC device which you want to use for the
4042 - CONFIG_SYS_MMC_ENV_DEV:
4044 Specifies which MMC device the environment is stored in.
4046 - CONFIG_SYS_MMC_ENV_PART (optional):
4048 Specifies which MMC partition the environment is stored in. If not
4049 set, defaults to partition 0, the user area. Common values might be
4050 1 (first MMC boot partition), 2 (second MMC boot partition).
4052 - CONFIG_ENV_OFFSET:
4055 These two #defines specify the offset and size of the environment
4056 area within the specified MMC device.
4058 If offset is positive (the usual case), it is treated as relative to
4059 the start of the MMC partition. If offset is negative, it is treated
4060 as relative to the end of the MMC partition. This can be useful if
4061 your board may be fitted with different MMC devices, which have
4062 different sizes for the MMC partitions, and you always want the
4063 environment placed at the very end of the partition, to leave the
4064 maximum possible space before it, to store other data.
4066 These two values are in units of bytes, but must be aligned to an
4067 MMC sector boundary.
4069 - CONFIG_ENV_OFFSET_REDUND (optional):
4071 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4072 hold a redundant copy of the environment data. This provides a
4073 valid backup copy in case the other copy is corrupted, e.g. due
4074 to a power failure during a "saveenv" operation.
4076 This value may also be positive or negative; this is handled in the
4077 same way as CONFIG_ENV_OFFSET.
4079 This value is also in units of bytes, but must also be aligned to
4080 an MMC sector boundary.
4082 - CONFIG_ENV_SIZE_REDUND (optional):
4084 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4085 set. If this value is set, it must be set to the same value as
4088 - CONFIG_SYS_SPI_INIT_OFFSET
4090 Defines offset to the initial SPI buffer area in DPRAM. The
4091 area is used at an early stage (ROM part) if the environment
4092 is configured to reside in the SPI EEPROM: We need a 520 byte
4093 scratch DPRAM area. It is used between the two initialization
4094 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4095 to be a good choice since it makes it far enough from the
4096 start of the data area as well as from the stack pointer.
4098 Please note that the environment is read-only until the monitor
4099 has been relocated to RAM and a RAM copy of the environment has been
4100 created; also, when using EEPROM you will have to use getenv_f()
4101 until then to read environment variables.
4103 The environment is protected by a CRC32 checksum. Before the monitor
4104 is relocated into RAM, as a result of a bad CRC you will be working
4105 with the compiled-in default environment - *silently*!!! [This is
4106 necessary, because the first environment variable we need is the
4107 "baudrate" setting for the console - if we have a bad CRC, we don't
4108 have any device yet where we could complain.]
4110 Note: once the monitor has been relocated, then it will complain if
4111 the default environment is used; a new CRC is computed as soon as you
4112 use the "saveenv" command to store a valid environment.
4114 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4115 Echo the inverted Ethernet link state to the fault LED.
4117 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4118 also needs to be defined.
4120 - CONFIG_SYS_FAULT_MII_ADDR:
4121 MII address of the PHY to check for the Ethernet link state.
4123 - CONFIG_NS16550_MIN_FUNCTIONS:
4124 Define this if you desire to only have use of the NS16550_init
4125 and NS16550_putc functions for the serial driver located at
4126 drivers/serial/ns16550.c. This option is useful for saving
4127 space for already greatly restricted images, including but not
4128 limited to NAND_SPL configurations.
4130 - CONFIG_DISPLAY_BOARDINFO
4131 Display information about the board that U-Boot is running on
4132 when U-Boot starts up. The board function checkboard() is called
4135 - CONFIG_DISPLAY_BOARDINFO_LATE
4136 Similar to the previous option, but display this information
4137 later, once stdio is running and output goes to the LCD, if
4140 - CONFIG_BOARD_SIZE_LIMIT:
4141 Maximum size of the U-Boot image. When defined, the
4142 build system checks that the actual size does not
4145 Low Level (hardware related) configuration options:
4146 ---------------------------------------------------
4148 - CONFIG_SYS_CACHELINE_SIZE:
4149 Cache Line Size of the CPU.
4151 - CONFIG_SYS_DEFAULT_IMMR:
4152 Default address of the IMMR after system reset.
4154 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4155 and RPXsuper) to be able to adjust the position of
4156 the IMMR register after a reset.
4158 - CONFIG_SYS_CCSRBAR_DEFAULT:
4159 Default (power-on reset) physical address of CCSR on Freescale
4162 - CONFIG_SYS_CCSRBAR:
4163 Virtual address of CCSR. On a 32-bit build, this is typically
4164 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4166 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4167 for cross-platform code that uses that macro instead.
4169 - CONFIG_SYS_CCSRBAR_PHYS:
4170 Physical address of CCSR. CCSR can be relocated to a new
4171 physical address, if desired. In this case, this macro should
4172 be set to that address. Otherwise, it should be set to the
4173 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4174 is typically relocated on 36-bit builds. It is recommended
4175 that this macro be defined via the _HIGH and _LOW macros:
4177 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4178 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4180 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4181 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4182 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4183 used in assembly code, so it must not contain typecasts or
4184 integer size suffixes (e.g. "ULL").
4186 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4187 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4188 used in assembly code, so it must not contain typecasts or
4189 integer size suffixes (e.g. "ULL").
4191 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4192 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4193 forced to a value that ensures that CCSR is not relocated.
4195 - Floppy Disk Support:
4196 CONFIG_SYS_FDC_DRIVE_NUMBER
4198 the default drive number (default value 0)
4200 CONFIG_SYS_ISA_IO_STRIDE
4202 defines the spacing between FDC chipset registers
4205 CONFIG_SYS_ISA_IO_OFFSET
4207 defines the offset of register from address. It
4208 depends on which part of the data bus is connected to
4209 the FDC chipset. (default value 0)
4211 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4212 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4215 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4216 fdc_hw_init() is called at the beginning of the FDC
4217 setup. fdc_hw_init() must be provided by the board
4218 source code. It is used to make hardware-dependent
4222 Most IDE controllers were designed to be connected with PCI
4223 interface. Only few of them were designed for AHB interface.
4224 When software is doing ATA command and data transfer to
4225 IDE devices through IDE-AHB controller, some additional
4226 registers accessing to these kind of IDE-AHB controller
4229 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4230 DO NOT CHANGE unless you know exactly what you're
4231 doing! (11-4) [MPC8xx/82xx systems only]
4233 - CONFIG_SYS_INIT_RAM_ADDR:
4235 Start address of memory area that can be used for
4236 initial data and stack; please note that this must be
4237 writable memory that is working WITHOUT special
4238 initialization, i. e. you CANNOT use normal RAM which
4239 will become available only after programming the
4240 memory controller and running certain initialization
4243 U-Boot uses the following memory types:
4244 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4245 - MPC824X: data cache
4246 - PPC4xx: data cache
4248 - CONFIG_SYS_GBL_DATA_OFFSET:
4250 Offset of the initial data structure in the memory
4251 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4252 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4253 data is located at the end of the available space
4254 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4255 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4256 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4257 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4260 On the MPC824X (or other systems that use the data
4261 cache for initial memory) the address chosen for
4262 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4263 point to an otherwise UNUSED address space between
4264 the top of RAM and the start of the PCI space.
4266 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4268 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4270 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4272 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4274 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4276 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4278 - CONFIG_SYS_OR_TIMING_SDRAM:
4281 - CONFIG_SYS_MAMR_PTA:
4282 periodic timer for refresh
4284 - CONFIG_SYS_DER: Debug Event Register (37-47)
4286 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4287 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4288 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4289 CONFIG_SYS_BR1_PRELIM:
4290 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4292 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4293 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4294 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4295 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4297 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4298 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4299 Machine Mode Register and Memory Periodic Timer
4300 Prescaler definitions (SDRAM timing)
4302 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4303 enable I2C microcode relocation patch (MPC8xx);
4304 define relocation offset in DPRAM [DSP2]
4306 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4307 enable SMC microcode relocation patch (MPC8xx);
4308 define relocation offset in DPRAM [SMC1]
4310 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4311 enable SPI microcode relocation patch (MPC8xx);
4312 define relocation offset in DPRAM [SCC4]
4314 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4315 Offset of the bootmode word in DPRAM used by post
4316 (Power On Self Tests). This definition overrides
4317 #define'd default value in commproc.h resp.
4320 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4321 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4322 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4323 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4324 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4325 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4326 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4327 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4328 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4330 - CONFIG_PCI_DISABLE_PCIE:
4331 Disable PCI-Express on systems where it is supported but not
4334 - CONFIG_PCI_ENUM_ONLY
4335 Only scan through and get the devices on the buses.
4336 Don't do any setup work, presumably because someone or
4337 something has already done it, and we don't need to do it
4338 a second time. Useful for platforms that are pre-booted
4339 by coreboot or similar.
4341 - CONFIG_PCI_INDIRECT_BRIDGE:
4342 Enable support for indirect PCI bridges.
4345 Chip has SRIO or not
4348 Board has SRIO 1 port available
4351 Board has SRIO 2 port available
4353 - CONFIG_SRIO_PCIE_BOOT_MASTER
4354 Board can support master function for Boot from SRIO and PCIE
4356 - CONFIG_SYS_SRIOn_MEM_VIRT:
4357 Virtual Address of SRIO port 'n' memory region
4359 - CONFIG_SYS_SRIOn_MEM_PHYS:
4360 Physical Address of SRIO port 'n' memory region
4362 - CONFIG_SYS_SRIOn_MEM_SIZE:
4363 Size of SRIO port 'n' memory region
4365 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4366 Defined to tell the NAND controller that the NAND chip is using
4368 Not all NAND drivers use this symbol.
4369 Example of drivers that use it:
4370 - drivers/mtd/nand/ndfc.c
4371 - drivers/mtd/nand/mxc_nand.c
4373 - CONFIG_SYS_NDFC_EBC0_CFG
4374 Sets the EBC0_CFG register for the NDFC. If not defined
4375 a default value will be used.
4378 Get DDR timing information from an I2C EEPROM. Common
4379 with pluggable memory modules such as SODIMMs
4382 I2C address of the SPD EEPROM
4384 - CONFIG_SYS_SPD_BUS_NUM
4385 If SPD EEPROM is on an I2C bus other than the first
4386 one, specify here. Note that the value must resolve
4387 to something your driver can deal with.
4389 - CONFIG_SYS_DDR_RAW_TIMING
4390 Get DDR timing information from other than SPD. Common with
4391 soldered DDR chips onboard without SPD. DDR raw timing
4392 parameters are extracted from datasheet and hard-coded into
4393 header files or board specific files.
4395 - CONFIG_FSL_DDR_INTERACTIVE
4396 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4398 - CONFIG_FSL_DDR_SYNC_REFRESH
4399 Enable sync of refresh for multiple controllers.
4401 - CONFIG_FSL_DDR_BIST
4402 Enable built-in memory test for Freescale DDR controllers.
4404 - CONFIG_SYS_83XX_DDR_USES_CS0
4405 Only for 83xx systems. If specified, then DDR should
4406 be configured using CS0 and CS1 instead of CS2 and CS3.
4408 - CONFIG_ETHER_ON_FEC[12]
4409 Define to enable FEC[12] on a 8xx series processor.
4411 - CONFIG_FEC[12]_PHY
4412 Define to the hardcoded PHY address which corresponds
4413 to the given FEC; i. e.
4414 #define CONFIG_FEC1_PHY 4
4415 means that the PHY with address 4 is connected to FEC1
4417 When set to -1, means to probe for first available.
4419 - CONFIG_FEC[12]_PHY_NORXERR
4420 The PHY does not have a RXERR line (RMII only).
4421 (so program the FEC to ignore it).
4424 Enable RMII mode for all FECs.
4425 Note that this is a global option, we can't
4426 have one FEC in standard MII mode and another in RMII mode.
4428 - CONFIG_CRC32_VERIFY
4429 Add a verify option to the crc32 command.
4432 => crc32 -v <address> <count> <crc32>
4434 Where address/count indicate a memory area
4435 and crc32 is the correct crc32 which the
4439 Add the "loopw" memory command. This only takes effect if
4440 the memory commands are activated globally (CONFIG_CMD_MEM).
4443 Add the "mdc" and "mwc" memory commands. These are cyclic
4448 This command will print 4 bytes (10,11,12,13) each 500 ms.
4450 => mwc.l 100 12345678 10
4451 This command will write 12345678 to address 100 all 10 ms.
4453 This only takes effect if the memory commands are activated
4454 globally (CONFIG_CMD_MEM).
4456 - CONFIG_SKIP_LOWLEVEL_INIT
4457 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4458 low level initializations (like setting up the memory
4459 controller) are omitted and/or U-Boot does not
4460 relocate itself into RAM.
4462 Normally this variable MUST NOT be defined. The only
4463 exception is when U-Boot is loaded (to RAM) by some
4464 other boot loader or by a debugger which performs
4465 these initializations itself.
4467 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4468 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4469 to be skipped. The normal CP15 init (such as enabling the
4470 instruction cache) is still performed.
4473 Modifies the behaviour of start.S when compiling a loader
4474 that is executed before the actual U-Boot. E.g. when
4475 compiling a NAND SPL.
4478 Modifies the behaviour of start.S when compiling a loader
4479 that is executed after the SPL and before the actual U-Boot.
4480 It is loaded by the SPL.
4482 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4483 Only for 85xx systems. If this variable is specified, the section
4484 .resetvec is not kept and the section .bootpg is placed in the
4485 previous 4k of the .text section.
4487 - CONFIG_ARCH_MAP_SYSMEM
4488 Generally U-Boot (and in particular the md command) uses
4489 effective address. It is therefore not necessary to regard
4490 U-Boot address as virtual addresses that need to be translated
4491 to physical addresses. However, sandbox requires this, since
4492 it maintains its own little RAM buffer which contains all
4493 addressable memory. This option causes some memory accesses
4494 to be mapped through map_sysmem() / unmap_sysmem().
4496 - CONFIG_X86_RESET_VECTOR
4497 If defined, the x86 reset vector code is included. This is not
4498 needed when U-Boot is running from Coreboot.
4500 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4501 Enables the RTC32K OSC on AM33xx based plattforms
4503 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4504 Option to disable subpage write in NAND driver
4505 driver that uses this:
4506 drivers/mtd/nand/davinci_nand.c
4508 Freescale QE/FMAN Firmware Support:
4509 -----------------------------------
4511 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4512 loading of "firmware", which is encoded in the QE firmware binary format.
4513 This firmware often needs to be loaded during U-Boot booting, so macros
4514 are used to identify the storage device (NOR flash, SPI, etc) and the address
4517 - CONFIG_SYS_FMAN_FW_ADDR
4518 The address in the storage device where the FMAN microcode is located. The
4519 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4522 - CONFIG_SYS_QE_FW_ADDR
4523 The address in the storage device where the QE microcode is located. The
4524 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4527 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4528 The maximum possible size of the firmware. The firmware binary format
4529 has a field that specifies the actual size of the firmware, but it
4530 might not be possible to read any part of the firmware unless some
4531 local storage is allocated to hold the entire firmware first.
4533 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4534 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4535 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4536 virtual address in NOR flash.
4538 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4539 Specifies that QE/FMAN firmware is located in NAND flash.
4540 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4542 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4543 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4544 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4546 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4547 Specifies that QE/FMAN firmware is located in the remote (master)
4548 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4549 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4550 window->master inbound window->master LAW->the ucode address in
4551 master's memory space.
4553 Freescale Layerscape Management Complex Firmware Support:
4554 ---------------------------------------------------------
4555 The Freescale Layerscape Management Complex (MC) supports the loading of
4557 This firmware often needs to be loaded during U-Boot booting, so macros
4558 are used to identify the storage device (NOR flash, SPI, etc) and the address
4561 - CONFIG_FSL_MC_ENET
4562 Enable the MC driver for Layerscape SoCs.
4564 Freescale Layerscape Debug Server Support:
4565 -------------------------------------------
4566 The Freescale Layerscape Debug Server Support supports the loading of
4567 "Debug Server firmware" and triggering SP boot-rom.
4568 This firmware often needs to be loaded during U-Boot booting.
4570 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4571 Define alignment of reserved memory MC requires
4576 In order to achieve reproducible builds, timestamps used in the U-Boot build
4577 process have to be set to a fixed value.
4579 This is done using the SOURCE_DATE_EPOCH environment variable.
4580 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4581 option for U-Boot or an environment variable in U-Boot.
4583 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4585 Building the Software:
4586 ======================
4588 Building U-Boot has been tested in several native build environments
4589 and in many different cross environments. Of course we cannot support
4590 all possibly existing versions of cross development tools in all
4591 (potentially obsolete) versions. In case of tool chain problems we
4592 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4593 which is extensively used to build and test U-Boot.
4595 If you are not using a native environment, it is assumed that you
4596 have GNU cross compiling tools available in your path. In this case,
4597 you must set the environment variable CROSS_COMPILE in your shell.
4598 Note that no changes to the Makefile or any other source files are
4599 necessary. For example using the ELDK on a 4xx CPU, please enter:
4601 $ CROSS_COMPILE=ppc_4xx-
4602 $ export CROSS_COMPILE
4604 Note: If you wish to generate Windows versions of the utilities in
4605 the tools directory you can use the MinGW toolchain
4606 (http://www.mingw.org). Set your HOST tools to the MinGW
4607 toolchain and execute 'make tools'. For example:
4609 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4611 Binaries such as tools/mkimage.exe will be created which can
4612 be executed on computers running Windows.
4614 U-Boot is intended to be simple to build. After installing the
4615 sources you must configure U-Boot for one specific board type. This
4620 where "NAME_defconfig" is the name of one of the existing configu-
4621 rations; see boards.cfg for supported names.
4623 Note: for some board special configuration names may exist; check if
4624 additional information is available from the board vendor; for
4625 instance, the TQM823L systems are available without (standard)
4626 or with LCD support. You can select such additional "features"
4627 when choosing the configuration, i. e.
4629 make TQM823L_defconfig
4630 - will configure for a plain TQM823L, i. e. no LCD support
4632 make TQM823L_LCD_defconfig
4633 - will configure for a TQM823L with U-Boot console on LCD
4638 Finally, type "make all", and you should get some working U-Boot
4639 images ready for download to / installation on your system:
4641 - "u-boot.bin" is a raw binary image
4642 - "u-boot" is an image in ELF binary format
4643 - "u-boot.srec" is in Motorola S-Record format
4645 By default the build is performed locally and the objects are saved
4646 in the source directory. One of the two methods can be used to change
4647 this behavior and build U-Boot to some external directory:
4649 1. Add O= to the make command line invocations:
4651 make O=/tmp/build distclean
4652 make O=/tmp/build NAME_defconfig
4653 make O=/tmp/build all
4655 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4657 export KBUILD_OUTPUT=/tmp/build
4662 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4666 Please be aware that the Makefiles assume you are using GNU make, so
4667 for instance on NetBSD you might need to use "gmake" instead of
4671 If the system board that you have is not listed, then you will need
4672 to port U-Boot to your hardware platform. To do this, follow these
4675 1. Create a new directory to hold your board specific code. Add any
4676 files you need. In your board directory, you will need at least
4677 the "Makefile" and a "<board>.c".
4678 2. Create a new configuration file "include/configs/<board>.h" for
4680 3. If you're porting U-Boot to a new CPU, then also create a new
4681 directory to hold your CPU specific code. Add any files you need.
4682 4. Run "make <board>_defconfig" with your new name.
4683 5. Type "make", and you should get a working "u-boot.srec" file
4684 to be installed on your target system.
4685 6. Debug and solve any problems that might arise.
4686 [Of course, this last step is much harder than it sounds.]
4689 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4690 ==============================================================
4692 If you have modified U-Boot sources (for instance added a new board
4693 or support for new devices, a new CPU, etc.) you are expected to
4694 provide feedback to the other developers. The feedback normally takes
4695 the form of a "patch", i. e. a context diff against a certain (latest
4696 official or latest in the git repository) version of U-Boot sources.
4698 But before you submit such a patch, please verify that your modifi-
4699 cation did not break existing code. At least make sure that *ALL* of
4700 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4701 just run the buildman script (tools/buildman/buildman), which will
4702 configure and build U-Boot for ALL supported system. Be warned, this
4703 will take a while. Please see the buildman README, or run 'buildman -H'
4707 See also "U-Boot Porting Guide" below.
4710 Monitor Commands - Overview:
4711 ============================
4713 go - start application at address 'addr'
4714 run - run commands in an environment variable
4715 bootm - boot application image from memory
4716 bootp - boot image via network using BootP/TFTP protocol
4717 bootz - boot zImage from memory
4718 tftpboot- boot image via network using TFTP protocol
4719 and env variables "ipaddr" and "serverip"
4720 (and eventually "gatewayip")
4721 tftpput - upload a file via network using TFTP protocol
4722 rarpboot- boot image via network using RARP/TFTP protocol
4723 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4724 loads - load S-Record file over serial line
4725 loadb - load binary file over serial line (kermit mode)
4727 mm - memory modify (auto-incrementing)
4728 nm - memory modify (constant address)
4729 mw - memory write (fill)
4731 cmp - memory compare
4732 crc32 - checksum calculation
4733 i2c - I2C sub-system
4734 sspi - SPI utility commands
4735 base - print or set address offset
4736 printenv- print environment variables
4737 setenv - set environment variables
4738 saveenv - save environment variables to persistent storage
4739 protect - enable or disable FLASH write protection
4740 erase - erase FLASH memory
4741 flinfo - print FLASH memory information
4742 nand - NAND memory operations (see doc/README.nand)
4743 bdinfo - print Board Info structure
4744 iminfo - print header information for application image
4745 coninfo - print console devices and informations
4746 ide - IDE sub-system
4747 loop - infinite loop on address range
4748 loopw - infinite write loop on address range
4749 mtest - simple RAM test
4750 icache - enable or disable instruction cache
4751 dcache - enable or disable data cache
4752 reset - Perform RESET of the CPU
4753 echo - echo args to console
4754 version - print monitor version
4755 help - print online help
4756 ? - alias for 'help'
4759 Monitor Commands - Detailed Description:
4760 ========================================
4764 For now: just type "help <command>".
4767 Environment Variables:
4768 ======================
4770 U-Boot supports user configuration using Environment Variables which
4771 can be made persistent by saving to Flash memory.
4773 Environment Variables are set using "setenv", printed using
4774 "printenv", and saved to Flash using "saveenv". Using "setenv"
4775 without a value can be used to delete a variable from the
4776 environment. As long as you don't save the environment you are
4777 working with an in-memory copy. In case the Flash area containing the
4778 environment is erased by accident, a default environment is provided.
4780 Some configuration options can be set using Environment Variables.
4782 List of environment variables (most likely not complete):
4784 baudrate - see CONFIG_BAUDRATE
4786 bootdelay - see CONFIG_BOOTDELAY
4788 bootcmd - see CONFIG_BOOTCOMMAND
4790 bootargs - Boot arguments when booting an RTOS image
4792 bootfile - Name of the image to load with TFTP
4794 bootm_low - Memory range available for image processing in the bootm
4795 command can be restricted. This variable is given as
4796 a hexadecimal number and defines lowest address allowed
4797 for use by the bootm command. See also "bootm_size"
4798 environment variable. Address defined by "bootm_low" is
4799 also the base of the initial memory mapping for the Linux
4800 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4803 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4804 This variable is given as a hexadecimal number and it
4805 defines the size of the memory region starting at base
4806 address bootm_low that is accessible by the Linux kernel
4807 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4808 as the default value if it is defined, and bootm_size is
4811 bootm_size - Memory range available for image processing in the bootm
4812 command can be restricted. This variable is given as
4813 a hexadecimal number and defines the size of the region
4814 allowed for use by the bootm command. See also "bootm_low"
4815 environment variable.
4817 updatefile - Location of the software update file on a TFTP server, used
4818 by the automatic software update feature. Please refer to
4819 documentation in doc/README.update for more details.
4821 autoload - if set to "no" (any string beginning with 'n'),
4822 "bootp" will just load perform a lookup of the
4823 configuration from the BOOTP server, but not try to
4824 load any image using TFTP
4826 autostart - if set to "yes", an image loaded using the "bootp",
4827 "rarpboot", "tftpboot" or "diskboot" commands will
4828 be automatically started (by internally calling
4831 If set to "no", a standalone image passed to the
4832 "bootm" command will be copied to the load address
4833 (and eventually uncompressed), but NOT be started.
4834 This can be used to load and uncompress arbitrary
4837 fdt_high - if set this restricts the maximum address that the
4838 flattened device tree will be copied into upon boot.
4839 For example, if you have a system with 1 GB memory
4840 at physical address 0x10000000, while Linux kernel
4841 only recognizes the first 704 MB as low memory, you
4842 may need to set fdt_high as 0x3C000000 to have the
4843 device tree blob be copied to the maximum address
4844 of the 704 MB low memory, so that Linux kernel can
4845 access it during the boot procedure.
4847 If this is set to the special value 0xFFFFFFFF then
4848 the fdt will not be copied at all on boot. For this
4849 to work it must reside in writable memory, have
4850 sufficient padding on the end of it for u-boot to
4851 add the information it needs into it, and the memory
4852 must be accessible by the kernel.
4854 fdtcontroladdr- if set this is the address of the control flattened
4855 device tree used by U-Boot when CONFIG_OF_CONTROL is
4858 i2cfast - (PPC405GP|PPC405EP only)
4859 if set to 'y' configures Linux I2C driver for fast
4860 mode (400kHZ). This environment variable is used in
4861 initialization code. So, for changes to be effective
4862 it must be saved and board must be reset.
4864 initrd_high - restrict positioning of initrd images:
4865 If this variable is not set, initrd images will be
4866 copied to the highest possible address in RAM; this
4867 is usually what you want since it allows for
4868 maximum initrd size. If for some reason you want to
4869 make sure that the initrd image is loaded below the
4870 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4871 variable to a value of "no" or "off" or "0".
4872 Alternatively, you can set it to a maximum upper
4873 address to use (U-Boot will still check that it
4874 does not overwrite the U-Boot stack and data).
4876 For instance, when you have a system with 16 MB
4877 RAM, and want to reserve 4 MB from use by Linux,
4878 you can do this by adding "mem=12M" to the value of
4879 the "bootargs" variable. However, now you must make
4880 sure that the initrd image is placed in the first
4881 12 MB as well - this can be done with
4883 setenv initrd_high 00c00000
4885 If you set initrd_high to 0xFFFFFFFF, this is an
4886 indication to U-Boot that all addresses are legal
4887 for the Linux kernel, including addresses in flash
4888 memory. In this case U-Boot will NOT COPY the
4889 ramdisk at all. This may be useful to reduce the
4890 boot time on your system, but requires that this
4891 feature is supported by your Linux kernel.
4893 ipaddr - IP address; needed for tftpboot command
4895 loadaddr - Default load address for commands like "bootp",
4896 "rarpboot", "tftpboot", "loadb" or "diskboot"
4898 loads_echo - see CONFIG_LOADS_ECHO
4900 serverip - TFTP server IP address; needed for tftpboot command
4902 bootretry - see CONFIG_BOOT_RETRY_TIME
4904 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4906 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4908 ethprime - controls which interface is used first.
4910 ethact - controls which interface is currently active.
4911 For example you can do the following
4913 => setenv ethact FEC
4914 => ping 192.168.0.1 # traffic sent on FEC
4915 => setenv ethact SCC
4916 => ping 10.0.0.1 # traffic sent on SCC
4918 ethrotate - When set to "no" U-Boot does not go through all
4919 available network interfaces.
4920 It just stays at the currently selected interface.
4922 netretry - When set to "no" each network operation will
4923 either succeed or fail without retrying.
4924 When set to "once" the network operation will
4925 fail when all the available network interfaces
4926 are tried once without success.
4927 Useful on scripts which control the retry operation
4930 npe_ucode - set load address for the NPE microcode
4932 silent_linux - If set then Linux will be told to boot silently, by
4933 changing the console to be empty. If "yes" it will be
4934 made silent. If "no" it will not be made silent. If
4935 unset, then it will be made silent if the U-Boot console
4938 tftpsrcp - If this is set, the value is used for TFTP's
4941 tftpdstp - If this is set, the value is used for TFTP's UDP
4942 destination port instead of the Well Know Port 69.
4944 tftpblocksize - Block size to use for TFTP transfers; if not set,
4945 we use the TFTP server's default block size
4947 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4948 seconds, minimum value is 1000 = 1 second). Defines
4949 when a packet is considered to be lost so it has to
4950 be retransmitted. The default is 5000 = 5 seconds.
4951 Lowering this value may make downloads succeed
4952 faster in networks with high packet loss rates or
4953 with unreliable TFTP servers.
4955 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4956 unit, minimum value = 0). Defines how many timeouts
4957 can happen during a single file transfer before that
4958 transfer is aborted. The default is 10, and 0 means
4959 'no timeouts allowed'. Increasing this value may help
4960 downloads succeed with high packet loss rates, or with
4961 unreliable TFTP servers or client hardware.
4963 vlan - When set to a value < 4095 the traffic over
4964 Ethernet is encapsulated/received over 802.1q
4967 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4968 Unsigned value, in milliseconds. If not set, the period will
4969 be either the default (28000), or a value based on
4970 CONFIG_NET_RETRY_COUNT, if defined. This value has
4971 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4973 The following image location variables contain the location of images
4974 used in booting. The "Image" column gives the role of the image and is
4975 not an environment variable name. The other columns are environment
4976 variable names. "File Name" gives the name of the file on a TFTP
4977 server, "RAM Address" gives the location in RAM the image will be
4978 loaded to, and "Flash Location" gives the image's address in NOR
4979 flash or offset in NAND flash.
4981 *Note* - these variables don't have to be defined for all boards, some
4982 boards currently use other variables for these purposes, and some
4983 boards use these variables for other purposes.
4985 Image File Name RAM Address Flash Location
4986 ----- --------- ----------- --------------
4987 u-boot u-boot u-boot_addr_r u-boot_addr
4988 Linux kernel bootfile kernel_addr_r kernel_addr
4989 device tree blob fdtfile fdt_addr_r fdt_addr
4990 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4992 The following environment variables may be used and automatically
4993 updated by the network boot commands ("bootp" and "rarpboot"),
4994 depending the information provided by your boot server:
4996 bootfile - see above
4997 dnsip - IP address of your Domain Name Server
4998 dnsip2 - IP address of your secondary Domain Name Server
4999 gatewayip - IP address of the Gateway (Router) to use
5000 hostname - Target hostname
5002 netmask - Subnet Mask
5003 rootpath - Pathname of the root filesystem on the NFS server
5004 serverip - see above
5007 There are two special Environment Variables:
5009 serial# - contains hardware identification information such
5010 as type string and/or serial number
5011 ethaddr - Ethernet address
5013 These variables can be set only once (usually during manufacturing of
5014 the board). U-Boot refuses to delete or overwrite these variables
5015 once they have been set once.
5018 Further special Environment Variables:
5020 ver - Contains the U-Boot version string as printed
5021 with the "version" command. This variable is
5022 readonly (see CONFIG_VERSION_VARIABLE).
5025 Please note that changes to some configuration parameters may take
5026 only effect after the next boot (yes, that's just like Windoze :-).
5029 Callback functions for environment variables:
5030 ---------------------------------------------
5032 For some environment variables, the behavior of u-boot needs to change
5033 when their values are changed. This functionality allows functions to
5034 be associated with arbitrary variables. On creation, overwrite, or
5035 deletion, the callback will provide the opportunity for some side
5036 effect to happen or for the change to be rejected.
5038 The callbacks are named and associated with a function using the
5039 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5041 These callbacks are associated with variables in one of two ways. The
5042 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5043 in the board configuration to a string that defines a list of
5044 associations. The list must be in the following format:
5046 entry = variable_name[:callback_name]
5049 If the callback name is not specified, then the callback is deleted.
5050 Spaces are also allowed anywhere in the list.
5052 Callbacks can also be associated by defining the ".callbacks" variable
5053 with the same list format above. Any association in ".callbacks" will
5054 override any association in the static list. You can define
5055 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5056 ".callbacks" environment variable in the default or embedded environment.
5058 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5059 regular expression. This allows multiple variables to be connected to
5060 the same callback without explicitly listing them all out.
5063 Command Line Parsing:
5064 =====================
5066 There are two different command line parsers available with U-Boot:
5067 the old "simple" one, and the much more powerful "hush" shell:
5069 Old, simple command line parser:
5070 --------------------------------
5072 - supports environment variables (through setenv / saveenv commands)
5073 - several commands on one line, separated by ';'
5074 - variable substitution using "... ${name} ..." syntax
5075 - special characters ('$', ';') can be escaped by prefixing with '\',
5077 setenv bootcmd bootm \${address}
5078 - You can also escape text by enclosing in single apostrophes, for example:
5079 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5084 - similar to Bourne shell, with control structures like
5085 if...then...else...fi, for...do...done; while...do...done,
5086 until...do...done, ...
5087 - supports environment ("global") variables (through setenv / saveenv
5088 commands) and local shell variables (through standard shell syntax
5089 "name=value"); only environment variables can be used with "run"
5095 (1) If a command line (or an environment variable executed by a "run"
5096 command) contains several commands separated by semicolon, and
5097 one of these commands fails, then the remaining commands will be
5100 (2) If you execute several variables with one call to run (i. e.
5101 calling run with a list of variables as arguments), any failing
5102 command will cause "run" to terminate, i. e. the remaining
5103 variables are not executed.
5105 Note for Redundant Ethernet Interfaces:
5106 =======================================
5108 Some boards come with redundant Ethernet interfaces; U-Boot supports
5109 such configurations and is capable of automatic selection of a
5110 "working" interface when needed. MAC assignment works as follows:
5112 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5113 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5114 "eth1addr" (=>eth1), "eth2addr", ...
5116 If the network interface stores some valid MAC address (for instance
5117 in SROM), this is used as default address if there is NO correspon-
5118 ding setting in the environment; if the corresponding environment
5119 variable is set, this overrides the settings in the card; that means:
5121 o If the SROM has a valid MAC address, and there is no address in the
5122 environment, the SROM's address is used.
5124 o If there is no valid address in the SROM, and a definition in the
5125 environment exists, then the value from the environment variable is
5128 o If both the SROM and the environment contain a MAC address, and
5129 both addresses are the same, this MAC address is used.
5131 o If both the SROM and the environment contain a MAC address, and the
5132 addresses differ, the value from the environment is used and a
5135 o If neither SROM nor the environment contain a MAC address, an error
5136 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5137 a random, locally-assigned MAC is used.
5139 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5140 will be programmed into hardware as part of the initialization process. This
5141 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5142 The naming convention is as follows:
5143 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5148 U-Boot is capable of booting (and performing other auxiliary operations on)
5149 images in two formats:
5151 New uImage format (FIT)
5152 -----------------------
5154 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5155 to Flattened Device Tree). It allows the use of images with multiple
5156 components (several kernels, ramdisks, etc.), with contents protected by
5157 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5163 Old image format is based on binary files which can be basically anything,
5164 preceded by a special header; see the definitions in include/image.h for
5165 details; basically, the header defines the following image properties:
5167 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5168 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5169 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5170 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5172 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5173 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5174 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5175 * Compression Type (uncompressed, gzip, bzip2)
5181 The header is marked by a special Magic Number, and both the header
5182 and the data portions of the image are secured against corruption by
5189 Although U-Boot should support any OS or standalone application
5190 easily, the main focus has always been on Linux during the design of
5193 U-Boot includes many features that so far have been part of some
5194 special "boot loader" code within the Linux kernel. Also, any
5195 "initrd" images to be used are no longer part of one big Linux image;
5196 instead, kernel and "initrd" are separate images. This implementation
5197 serves several purposes:
5199 - the same features can be used for other OS or standalone
5200 applications (for instance: using compressed images to reduce the
5201 Flash memory footprint)
5203 - it becomes much easier to port new Linux kernel versions because
5204 lots of low-level, hardware dependent stuff are done by U-Boot
5206 - the same Linux kernel image can now be used with different "initrd"
5207 images; of course this also means that different kernel images can
5208 be run with the same "initrd". This makes testing easier (you don't
5209 have to build a new "zImage.initrd" Linux image when you just
5210 change a file in your "initrd"). Also, a field-upgrade of the
5211 software is easier now.
5217 Porting Linux to U-Boot based systems:
5218 ---------------------------------------
5220 U-Boot cannot save you from doing all the necessary modifications to
5221 configure the Linux device drivers for use with your target hardware
5222 (no, we don't intend to provide a full virtual machine interface to
5225 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5227 Just make sure your machine specific header file (for instance
5228 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5229 Information structure as we define in include/asm-<arch>/u-boot.h,
5230 and make sure that your definition of IMAP_ADDR uses the same value
5231 as your U-Boot configuration in CONFIG_SYS_IMMR.
5233 Note that U-Boot now has a driver model, a unified model for drivers.
5234 If you are adding a new driver, plumb it into driver model. If there
5235 is no uclass available, you are encouraged to create one. See
5239 Configuring the Linux kernel:
5240 -----------------------------
5242 No specific requirements for U-Boot. Make sure you have some root
5243 device (initial ramdisk, NFS) for your target system.
5246 Building a Linux Image:
5247 -----------------------
5249 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5250 not used. If you use recent kernel source, a new build target
5251 "uImage" will exist which automatically builds an image usable by
5252 U-Boot. Most older kernels also have support for a "pImage" target,
5253 which was introduced for our predecessor project PPCBoot and uses a
5254 100% compatible format.
5258 make TQM850L_defconfig
5263 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5264 encapsulate a compressed Linux kernel image with header information,
5265 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5267 * build a standard "vmlinux" kernel image (in ELF binary format):
5269 * convert the kernel into a raw binary image:
5271 ${CROSS_COMPILE}-objcopy -O binary \
5272 -R .note -R .comment \
5273 -S vmlinux linux.bin
5275 * compress the binary image:
5279 * package compressed binary image for U-Boot:
5281 mkimage -A ppc -O linux -T kernel -C gzip \
5282 -a 0 -e 0 -n "Linux Kernel Image" \
5283 -d linux.bin.gz uImage
5286 The "mkimage" tool can also be used to create ramdisk images for use
5287 with U-Boot, either separated from the Linux kernel image, or
5288 combined into one file. "mkimage" encapsulates the images with a 64
5289 byte header containing information about target architecture,
5290 operating system, image type, compression method, entry points, time
5291 stamp, CRC32 checksums, etc.
5293 "mkimage" can be called in two ways: to verify existing images and
5294 print the header information, or to build new images.
5296 In the first form (with "-l" option) mkimage lists the information
5297 contained in the header of an existing U-Boot image; this includes
5298 checksum verification:
5300 tools/mkimage -l image
5301 -l ==> list image header information
5303 The second form (with "-d" option) is used to build a U-Boot image
5304 from a "data file" which is used as image payload:
5306 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5307 -n name -d data_file image
5308 -A ==> set architecture to 'arch'
5309 -O ==> set operating system to 'os'
5310 -T ==> set image type to 'type'
5311 -C ==> set compression type 'comp'
5312 -a ==> set load address to 'addr' (hex)
5313 -e ==> set entry point to 'ep' (hex)
5314 -n ==> set image name to 'name'
5315 -d ==> use image data from 'datafile'
5317 Right now, all Linux kernels for PowerPC systems use the same load
5318 address (0x00000000), but the entry point address depends on the
5321 - 2.2.x kernels have the entry point at 0x0000000C,
5322 - 2.3.x and later kernels have the entry point at 0x00000000.
5324 So a typical call to build a U-Boot image would read:
5326 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5327 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5328 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5329 > examples/uImage.TQM850L
5330 Image Name: 2.4.4 kernel for TQM850L
5331 Created: Wed Jul 19 02:34:59 2000
5332 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5333 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5334 Load Address: 0x00000000
5335 Entry Point: 0x00000000
5337 To verify the contents of the image (or check for corruption):
5339 -> tools/mkimage -l examples/uImage.TQM850L
5340 Image Name: 2.4.4 kernel for TQM850L
5341 Created: Wed Jul 19 02:34:59 2000
5342 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5343 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5344 Load Address: 0x00000000
5345 Entry Point: 0x00000000
5347 NOTE: for embedded systems where boot time is critical you can trade
5348 speed for memory and install an UNCOMPRESSED image instead: this
5349 needs more space in Flash, but boots much faster since it does not
5350 need to be uncompressed:
5352 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5353 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5354 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5355 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5356 > examples/uImage.TQM850L-uncompressed
5357 Image Name: 2.4.4 kernel for TQM850L
5358 Created: Wed Jul 19 02:34:59 2000
5359 Image Type: PowerPC Linux Kernel Image (uncompressed)
5360 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5361 Load Address: 0x00000000
5362 Entry Point: 0x00000000
5365 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5366 when your kernel is intended to use an initial ramdisk:
5368 -> tools/mkimage -n 'Simple Ramdisk Image' \
5369 > -A ppc -O linux -T ramdisk -C gzip \
5370 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5371 Image Name: Simple Ramdisk Image
5372 Created: Wed Jan 12 14:01:50 2000
5373 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5374 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5375 Load Address: 0x00000000
5376 Entry Point: 0x00000000
5378 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5379 option performs the converse operation of the mkimage's second form (the "-d"
5380 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5383 tools/dumpimage -i image -T type -p position data_file
5384 -i ==> extract from the 'image' a specific 'data_file'
5385 -T ==> set image type to 'type'
5386 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5389 Installing a Linux Image:
5390 -------------------------
5392 To downloading a U-Boot image over the serial (console) interface,
5393 you must convert the image to S-Record format:
5395 objcopy -I binary -O srec examples/image examples/image.srec
5397 The 'objcopy' does not understand the information in the U-Boot
5398 image header, so the resulting S-Record file will be relative to
5399 address 0x00000000. To load it to a given address, you need to
5400 specify the target address as 'offset' parameter with the 'loads'
5403 Example: install the image to address 0x40100000 (which on the
5404 TQM8xxL is in the first Flash bank):
5406 => erase 40100000 401FFFFF
5412 ## Ready for S-Record download ...
5413 ~>examples/image.srec
5414 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5416 15989 15990 15991 15992
5417 [file transfer complete]
5419 ## Start Addr = 0x00000000
5422 You can check the success of the download using the 'iminfo' command;
5423 this includes a checksum verification so you can be sure no data
5424 corruption happened:
5428 ## Checking Image at 40100000 ...
5429 Image Name: 2.2.13 for initrd on TQM850L
5430 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5431 Data Size: 335725 Bytes = 327 kB = 0 MB
5432 Load Address: 00000000
5433 Entry Point: 0000000c
5434 Verifying Checksum ... OK
5440 The "bootm" command is used to boot an application that is stored in
5441 memory (RAM or Flash). In case of a Linux kernel image, the contents
5442 of the "bootargs" environment variable is passed to the kernel as
5443 parameters. You can check and modify this variable using the
5444 "printenv" and "setenv" commands:
5447 => printenv bootargs
5448 bootargs=root=/dev/ram
5450 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5452 => printenv bootargs
5453 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5456 ## Booting Linux kernel at 40020000 ...
5457 Image Name: 2.2.13 for NFS on TQM850L
5458 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5459 Data Size: 381681 Bytes = 372 kB = 0 MB
5460 Load Address: 00000000
5461 Entry Point: 0000000c
5462 Verifying Checksum ... OK
5463 Uncompressing Kernel Image ... OK
5464 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
5465 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5466 time_init: decrementer frequency = 187500000/60
5467 Calibrating delay loop... 49.77 BogoMIPS
5468 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5471 If you want to boot a Linux kernel with initial RAM disk, you pass
5472 the memory addresses of both the kernel and the initrd image (PPBCOOT
5473 format!) to the "bootm" command:
5475 => imi 40100000 40200000
5477 ## Checking Image at 40100000 ...
5478 Image Name: 2.2.13 for initrd on TQM850L
5479 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5480 Data Size: 335725 Bytes = 327 kB = 0 MB
5481 Load Address: 00000000
5482 Entry Point: 0000000c
5483 Verifying Checksum ... OK
5485 ## Checking Image at 40200000 ...
5486 Image Name: Simple Ramdisk Image
5487 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5488 Data Size: 566530 Bytes = 553 kB = 0 MB
5489 Load Address: 00000000
5490 Entry Point: 00000000
5491 Verifying Checksum ... OK
5493 => bootm 40100000 40200000
5494 ## Booting Linux kernel at 40100000 ...
5495 Image Name: 2.2.13 for initrd on TQM850L
5496 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5497 Data Size: 335725 Bytes = 327 kB = 0 MB
5498 Load Address: 00000000
5499 Entry Point: 0000000c
5500 Verifying Checksum ... OK
5501 Uncompressing Kernel Image ... OK
5502 ## Loading RAMDisk Image at 40200000 ...
5503 Image Name: Simple Ramdisk Image
5504 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5505 Data Size: 566530 Bytes = 553 kB = 0 MB
5506 Load Address: 00000000
5507 Entry Point: 00000000
5508 Verifying Checksum ... OK
5509 Loading Ramdisk ... OK
5510 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
5511 Boot arguments: root=/dev/ram
5512 time_init: decrementer frequency = 187500000/60
5513 Calibrating delay loop... 49.77 BogoMIPS
5515 RAMDISK: Compressed image found at block 0
5516 VFS: Mounted root (ext2 filesystem).
5520 Boot Linux and pass a flat device tree:
5523 First, U-Boot must be compiled with the appropriate defines. See the section
5524 titled "Linux Kernel Interface" above for a more in depth explanation. The
5525 following is an example of how to start a kernel and pass an updated
5531 oft=oftrees/mpc8540ads.dtb
5532 => tftp $oftaddr $oft
5533 Speed: 1000, full duplex
5535 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5536 Filename 'oftrees/mpc8540ads.dtb'.
5537 Load address: 0x300000
5540 Bytes transferred = 4106 (100a hex)
5541 => tftp $loadaddr $bootfile
5542 Speed: 1000, full duplex
5544 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5546 Load address: 0x200000
5547 Loading:############
5549 Bytes transferred = 1029407 (fb51f hex)
5554 => bootm $loadaddr - $oftaddr
5555 ## Booting image at 00200000 ...
5556 Image Name: Linux-2.6.17-dirty
5557 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5558 Data Size: 1029343 Bytes = 1005.2 kB
5559 Load Address: 00000000
5560 Entry Point: 00000000
5561 Verifying Checksum ... OK
5562 Uncompressing Kernel Image ... OK
5563 Booting using flat device tree at 0x300000
5564 Using MPC85xx ADS machine description
5565 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5569 More About U-Boot Image Types:
5570 ------------------------------
5572 U-Boot supports the following image types:
5574 "Standalone Programs" are directly runnable in the environment
5575 provided by U-Boot; it is expected that (if they behave
5576 well) you can continue to work in U-Boot after return from
5577 the Standalone Program.
5578 "OS Kernel Images" are usually images of some Embedded OS which
5579 will take over control completely. Usually these programs
5580 will install their own set of exception handlers, device
5581 drivers, set up the MMU, etc. - this means, that you cannot
5582 expect to re-enter U-Boot except by resetting the CPU.
5583 "RAMDisk Images" are more or less just data blocks, and their
5584 parameters (address, size) are passed to an OS kernel that is
5586 "Multi-File Images" contain several images, typically an OS
5587 (Linux) kernel image and one or more data images like
5588 RAMDisks. This construct is useful for instance when you want
5589 to boot over the network using BOOTP etc., where the boot
5590 server provides just a single image file, but you want to get
5591 for instance an OS kernel and a RAMDisk image.
5593 "Multi-File Images" start with a list of image sizes, each
5594 image size (in bytes) specified by an "uint32_t" in network
5595 byte order. This list is terminated by an "(uint32_t)0".
5596 Immediately after the terminating 0 follow the images, one by
5597 one, all aligned on "uint32_t" boundaries (size rounded up to
5598 a multiple of 4 bytes).
5600 "Firmware Images" are binary images containing firmware (like
5601 U-Boot or FPGA images) which usually will be programmed to
5604 "Script files" are command sequences that will be executed by
5605 U-Boot's command interpreter; this feature is especially
5606 useful when you configure U-Boot to use a real shell (hush)
5607 as command interpreter.
5609 Booting the Linux zImage:
5610 -------------------------
5612 On some platforms, it's possible to boot Linux zImage. This is done
5613 using the "bootz" command. The syntax of "bootz" command is the same
5614 as the syntax of "bootm" command.
5616 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5617 kernel with raw initrd images. The syntax is slightly different, the
5618 address of the initrd must be augmented by it's size, in the following
5619 format: "<initrd addres>:<initrd size>".
5625 One of the features of U-Boot is that you can dynamically load and
5626 run "standalone" applications, which can use some resources of
5627 U-Boot like console I/O functions or interrupt services.
5629 Two simple examples are included with the sources:
5634 'examples/hello_world.c' contains a small "Hello World" Demo
5635 application; it is automatically compiled when you build U-Boot.
5636 It's configured to run at address 0x00040004, so you can play with it
5640 ## Ready for S-Record download ...
5641 ~>examples/hello_world.srec
5642 1 2 3 4 5 6 7 8 9 10 11 ...
5643 [file transfer complete]
5645 ## Start Addr = 0x00040004
5647 => go 40004 Hello World! This is a test.
5648 ## Starting application at 0x00040004 ...
5659 Hit any key to exit ...
5661 ## Application terminated, rc = 0x0
5663 Another example, which demonstrates how to register a CPM interrupt
5664 handler with the U-Boot code, can be found in 'examples/timer.c'.
5665 Here, a CPM timer is set up to generate an interrupt every second.
5666 The interrupt service routine is trivial, just printing a '.'
5667 character, but this is just a demo program. The application can be
5668 controlled by the following keys:
5670 ? - print current values og the CPM Timer registers
5671 b - enable interrupts and start timer
5672 e - stop timer and disable interrupts
5673 q - quit application
5676 ## Ready for S-Record download ...
5677 ~>examples/timer.srec
5678 1 2 3 4 5 6 7 8 9 10 11 ...
5679 [file transfer complete]
5681 ## Start Addr = 0x00040004
5684 ## Starting application at 0x00040004 ...
5687 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5690 [q, b, e, ?] Set interval 1000000 us
5693 [q, b, e, ?] ........
5694 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5697 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5700 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5703 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5705 [q, b, e, ?] ...Stopping timer
5707 [q, b, e, ?] ## Application terminated, rc = 0x0
5713 Over time, many people have reported problems when trying to use the
5714 "minicom" terminal emulation program for serial download. I (wd)
5715 consider minicom to be broken, and recommend not to use it. Under
5716 Unix, I recommend to use C-Kermit for general purpose use (and
5717 especially for kermit binary protocol download ("loadb" command), and
5718 use "cu" for S-Record download ("loads" command). See
5719 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5720 for help with kermit.
5723 Nevertheless, if you absolutely want to use it try adding this
5724 configuration to your "File transfer protocols" section:
5726 Name Program Name U/D FullScr IO-Red. Multi
5727 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5728 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5734 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5735 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5737 Building requires a cross environment; it is known to work on
5738 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5739 need gmake since the Makefiles are not compatible with BSD make).
5740 Note that the cross-powerpc package does not install include files;
5741 attempting to build U-Boot will fail because <machine/ansi.h> is
5742 missing. This file has to be installed and patched manually:
5744 # cd /usr/pkg/cross/powerpc-netbsd/include
5746 # ln -s powerpc machine
5747 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5748 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5750 Native builds *don't* work due to incompatibilities between native
5751 and U-Boot include files.
5753 Booting assumes that (the first part of) the image booted is a
5754 stage-2 loader which in turn loads and then invokes the kernel
5755 proper. Loader sources will eventually appear in the NetBSD source
5756 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5757 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5760 Implementation Internals:
5761 =========================
5763 The following is not intended to be a complete description of every
5764 implementation detail. However, it should help to understand the
5765 inner workings of U-Boot and make it easier to port it to custom
5769 Initial Stack, Global Data:
5770 ---------------------------
5772 The implementation of U-Boot is complicated by the fact that U-Boot
5773 starts running out of ROM (flash memory), usually without access to
5774 system RAM (because the memory controller is not initialized yet).
5775 This means that we don't have writable Data or BSS segments, and BSS
5776 is not initialized as zero. To be able to get a C environment working
5777 at all, we have to allocate at least a minimal stack. Implementation
5778 options for this are defined and restricted by the CPU used: Some CPU
5779 models provide on-chip memory (like the IMMR area on MPC8xx and
5780 MPC826x processors), on others (parts of) the data cache can be
5781 locked as (mis-) used as memory, etc.
5783 Chris Hallinan posted a good summary of these issues to the
5784 U-Boot mailing list:
5786 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5787 From: "Chris Hallinan" <clh@net1plus.com>
5788 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5791 Correct me if I'm wrong, folks, but the way I understand it
5792 is this: Using DCACHE as initial RAM for Stack, etc, does not
5793 require any physical RAM backing up the cache. The cleverness
5794 is that the cache is being used as a temporary supply of
5795 necessary storage before the SDRAM controller is setup. It's
5796 beyond the scope of this list to explain the details, but you
5797 can see how this works by studying the cache architecture and
5798 operation in the architecture and processor-specific manuals.
5800 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5801 is another option for the system designer to use as an
5802 initial stack/RAM area prior to SDRAM being available. Either
5803 option should work for you. Using CS 4 should be fine if your
5804 board designers haven't used it for something that would
5805 cause you grief during the initial boot! It is frequently not
5808 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5809 with your processor/board/system design. The default value
5810 you will find in any recent u-boot distribution in
5811 walnut.h should work for you. I'd set it to a value larger
5812 than your SDRAM module. If you have a 64MB SDRAM module, set
5813 it above 400_0000. Just make sure your board has no resources
5814 that are supposed to respond to that address! That code in
5815 start.S has been around a while and should work as is when
5816 you get the config right.
5821 It is essential to remember this, since it has some impact on the C
5822 code for the initialization procedures:
5824 * Initialized global data (data segment) is read-only. Do not attempt
5827 * Do not use any uninitialized global data (or implicitly initialized
5828 as zero data - BSS segment) at all - this is undefined, initiali-
5829 zation is performed later (when relocating to RAM).
5831 * Stack space is very limited. Avoid big data buffers or things like
5834 Having only the stack as writable memory limits means we cannot use
5835 normal global data to share information between the code. But it
5836 turned out that the implementation of U-Boot can be greatly
5837 simplified by making a global data structure (gd_t) available to all
5838 functions. We could pass a pointer to this data as argument to _all_
5839 functions, but this would bloat the code. Instead we use a feature of
5840 the GCC compiler (Global Register Variables) to share the data: we
5841 place a pointer (gd) to the global data into a register which we
5842 reserve for this purpose.
5844 When choosing a register for such a purpose we are restricted by the
5845 relevant (E)ABI specifications for the current architecture, and by
5846 GCC's implementation.
5848 For PowerPC, the following registers have specific use:
5850 R2: reserved for system use
5851 R3-R4: parameter passing and return values
5852 R5-R10: parameter passing
5853 R13: small data area pointer
5857 (U-Boot also uses R12 as internal GOT pointer. r12
5858 is a volatile register so r12 needs to be reset when
5859 going back and forth between asm and C)
5861 ==> U-Boot will use R2 to hold a pointer to the global data
5863 Note: on PPC, we could use a static initializer (since the
5864 address of the global data structure is known at compile time),
5865 but it turned out that reserving a register results in somewhat
5866 smaller code - although the code savings are not that big (on
5867 average for all boards 752 bytes for the whole U-Boot image,
5868 624 text + 127 data).
5870 On ARM, the following registers are used:
5872 R0: function argument word/integer result
5873 R1-R3: function argument word
5874 R9: platform specific
5875 R10: stack limit (used only if stack checking is enabled)
5876 R11: argument (frame) pointer
5877 R12: temporary workspace
5880 R15: program counter
5882 ==> U-Boot will use R9 to hold a pointer to the global data
5884 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5886 On Nios II, the ABI is documented here:
5887 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5889 ==> U-Boot will use gp to hold a pointer to the global data
5891 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5892 to access small data sections, so gp is free.
5894 On NDS32, the following registers are used:
5896 R0-R1: argument/return
5898 R15: temporary register for assembler
5899 R16: trampoline register
5900 R28: frame pointer (FP)
5901 R29: global pointer (GP)
5902 R30: link register (LP)
5903 R31: stack pointer (SP)
5904 PC: program counter (PC)
5906 ==> U-Boot will use R10 to hold a pointer to the global data
5908 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5909 or current versions of GCC may "optimize" the code too much.
5914 U-Boot runs in system state and uses physical addresses, i.e. the
5915 MMU is not used either for address mapping nor for memory protection.
5917 The available memory is mapped to fixed addresses using the memory
5918 controller. In this process, a contiguous block is formed for each
5919 memory type (Flash, SDRAM, SRAM), even when it consists of several
5920 physical memory banks.
5922 U-Boot is installed in the first 128 kB of the first Flash bank (on
5923 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5924 booting and sizing and initializing DRAM, the code relocates itself
5925 to the upper end of DRAM. Immediately below the U-Boot code some
5926 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5927 configuration setting]. Below that, a structure with global Board
5928 Info data is placed, followed by the stack (growing downward).
5930 Additionally, some exception handler code is copied to the low 8 kB
5931 of DRAM (0x00000000 ... 0x00001FFF).
5933 So a typical memory configuration with 16 MB of DRAM could look like
5936 0x0000 0000 Exception Vector code
5939 0x0000 2000 Free for Application Use
5945 0x00FB FF20 Monitor Stack (Growing downward)
5946 0x00FB FFAC Board Info Data and permanent copy of global data
5947 0x00FC 0000 Malloc Arena
5950 0x00FE 0000 RAM Copy of Monitor Code
5951 ... eventually: LCD or video framebuffer
5952 ... eventually: pRAM (Protected RAM - unchanged by reset)
5953 0x00FF FFFF [End of RAM]
5956 System Initialization:
5957 ----------------------
5959 In the reset configuration, U-Boot starts at the reset entry point
5960 (on most PowerPC systems at address 0x00000100). Because of the reset
5961 configuration for CS0# this is a mirror of the on board Flash memory.
5962 To be able to re-map memory U-Boot then jumps to its link address.
5963 To be able to implement the initialization code in C, a (small!)
5964 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5965 which provide such a feature like MPC8xx or MPC8260), or in a locked
5966 part of the data cache. After that, U-Boot initializes the CPU core,
5967 the caches and the SIU.
5969 Next, all (potentially) available memory banks are mapped using a
5970 preliminary mapping. For example, we put them on 512 MB boundaries
5971 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5972 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5973 programmed for SDRAM access. Using the temporary configuration, a
5974 simple memory test is run that determines the size of the SDRAM
5977 When there is more than one SDRAM bank, and the banks are of
5978 different size, the largest is mapped first. For equal size, the first
5979 bank (CS2#) is mapped first. The first mapping is always for address
5980 0x00000000, with any additional banks following immediately to create
5981 contiguous memory starting from 0.
5983 Then, the monitor installs itself at the upper end of the SDRAM area
5984 and allocates memory for use by malloc() and for the global Board
5985 Info data; also, the exception vector code is copied to the low RAM
5986 pages, and the final stack is set up.
5988 Only after this relocation will you have a "normal" C environment;
5989 until that you are restricted in several ways, mostly because you are
5990 running from ROM, and because the code will have to be relocated to a
5994 U-Boot Porting Guide:
5995 ----------------------
5997 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6001 int main(int argc, char *argv[])
6003 sighandler_t no_more_time;
6005 signal(SIGALRM, no_more_time);
6006 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6008 if (available_money > available_manpower) {
6009 Pay consultant to port U-Boot;
6013 Download latest U-Boot source;
6015 Subscribe to u-boot mailing list;
6018 email("Hi, I am new to U-Boot, how do I get started?");
6021 Read the README file in the top level directory;
6022 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6023 Read applicable doc/*.README;
6024 Read the source, Luke;
6025 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6028 if (available_money > toLocalCurrency ($2500))
6031 Add a lot of aggravation and time;
6033 if (a similar board exists) { /* hopefully... */
6034 cp -a board/<similar> board/<myboard>
6035 cp include/configs/<similar>.h include/configs/<myboard>.h
6037 Create your own board support subdirectory;
6038 Create your own board include/configs/<myboard>.h file;
6040 Edit new board/<myboard> files
6041 Edit new include/configs/<myboard>.h
6046 Add / modify source code;
6050 email("Hi, I am having problems...");
6052 Send patch file to the U-Boot email list;
6053 if (reasonable critiques)
6054 Incorporate improvements from email list code review;
6056 Defend code as written;
6062 void no_more_time (int sig)
6071 All contributions to U-Boot should conform to the Linux kernel
6072 coding style; see the file "Documentation/CodingStyle" and the script
6073 "scripts/Lindent" in your Linux kernel source directory.
6075 Source files originating from a different project (for example the
6076 MTD subsystem) are generally exempt from these guidelines and are not
6077 reformatted to ease subsequent migration to newer versions of those
6080 Please note that U-Boot is implemented in C (and to some small parts in
6081 Assembler); no C++ is used, so please do not use C++ style comments (//)
6084 Please also stick to the following formatting rules:
6085 - remove any trailing white space
6086 - use TAB characters for indentation and vertical alignment, not spaces
6087 - make sure NOT to use DOS '\r\n' line feeds
6088 - do not add more than 2 consecutive empty lines to source files
6089 - do not add trailing empty lines to source files
6091 Submissions which do not conform to the standards may be returned
6092 with a request to reformat the changes.
6098 Since the number of patches for U-Boot is growing, we need to
6099 establish some rules. Submissions which do not conform to these rules
6100 may be rejected, even when they contain important and valuable stuff.
6102 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6104 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6105 see http://lists.denx.de/mailman/listinfo/u-boot
6107 When you send a patch, please include the following information with
6110 * For bug fixes: a description of the bug and how your patch fixes
6111 this bug. Please try to include a way of demonstrating that the
6112 patch actually fixes something.
6114 * For new features: a description of the feature and your
6117 * A CHANGELOG entry as plaintext (separate from the patch)
6119 * For major contributions, add a MAINTAINERS file with your
6120 information and associated file and directory references.
6122 * When you add support for a new board, don't forget to add a
6123 maintainer e-mail address to the boards.cfg file, too.
6125 * If your patch adds new configuration options, don't forget to
6126 document these in the README file.
6128 * The patch itself. If you are using git (which is *strongly*
6129 recommended) you can easily generate the patch using the
6130 "git format-patch". If you then use "git send-email" to send it to
6131 the U-Boot mailing list, you will avoid most of the common problems
6132 with some other mail clients.
6134 If you cannot use git, use "diff -purN OLD NEW". If your version of
6135 diff does not support these options, then get the latest version of
6138 The current directory when running this command shall be the parent
6139 directory of the U-Boot source tree (i. e. please make sure that
6140 your patch includes sufficient directory information for the
6143 We prefer patches as plain text. MIME attachments are discouraged,
6144 and compressed attachments must not be used.
6146 * If one logical set of modifications affects or creates several
6147 files, all these changes shall be submitted in a SINGLE patch file.
6149 * Changesets that contain different, unrelated modifications shall be
6150 submitted as SEPARATE patches, one patch per changeset.
6155 * Before sending the patch, run the buildman script on your patched
6156 source tree and make sure that no errors or warnings are reported
6157 for any of the boards.
6159 * Keep your modifications to the necessary minimum: A patch
6160 containing several unrelated changes or arbitrary reformats will be
6161 returned with a request to re-formatting / split it.
6163 * If you modify existing code, make sure that your new code does not
6164 add to the memory footprint of the code ;-) Small is beautiful!
6165 When adding new features, these should compile conditionally only
6166 (using #ifdef), and the resulting code with the new feature
6167 disabled must not need more memory than the old code without your
6170 * Remember that there is a size limit of 100 kB per message on the
6171 u-boot mailing list. Bigger patches will be moderated. If they are
6172 reasonable and not too big, they will be acknowledged. But patches
6173 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob