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 selecting 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_ECHO echo arguments
834 CONFIG_CMD_EDITENV edit env variable
835 CONFIG_CMD_EEPROM * EEPROM read/write support
836 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
837 CONFIG_CMD_ELF * bootelf, bootvx
838 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
839 CONFIG_CMD_ENV_FLAGS * display details about env flags
840 CONFIG_CMD_ENV_EXISTS * check existence of env variable
841 CONFIG_CMD_EXPORTENV * export the environment
842 CONFIG_CMD_EXT2 * ext2 command support
843 CONFIG_CMD_EXT4 * ext4 command support
844 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
845 that work for multiple fs types
846 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
847 CONFIG_CMD_SAVEENV saveenv
848 CONFIG_CMD_FDC * Floppy Disk Support
849 CONFIG_CMD_FAT * FAT command support
850 CONFIG_CMD_FLASH flinfo, erase, protect
851 CONFIG_CMD_FPGA FPGA device initialization support
852 CONFIG_CMD_FUSE * Device fuse support
853 CONFIG_CMD_GETTIME * Get time since boot
854 CONFIG_CMD_GO * the 'go' command (exec code)
855 CONFIG_CMD_GREPENV * search environment
856 CONFIG_CMD_HASH * calculate hash / digest
857 CONFIG_CMD_I2C * I2C serial bus support
858 CONFIG_CMD_IDE * IDE harddisk support
859 CONFIG_CMD_IMI iminfo
860 CONFIG_CMD_IMLS List all images found in NOR flash
861 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
862 CONFIG_CMD_IMMAP * IMMR dump support
863 CONFIG_CMD_IOTRACE * I/O tracing for debugging
864 CONFIG_CMD_IMPORTENV * import an environment
865 CONFIG_CMD_INI * import data from an ini file into the env
866 CONFIG_CMD_IRQ * irqinfo
867 CONFIG_CMD_ITEST Integer/string test of 2 values
868 CONFIG_CMD_JFFS2 * JFFS2 Support
869 CONFIG_CMD_KGDB * kgdb
870 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
871 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
873 CONFIG_CMD_LOADB loadb
874 CONFIG_CMD_LOADS loads
875 CONFIG_CMD_MD5SUM * print md5 message digest
876 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
877 CONFIG_CMD_MEMINFO * Display detailed memory information
878 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
880 CONFIG_CMD_MEMTEST * mtest
881 CONFIG_CMD_MISC Misc functions like sleep etc
882 CONFIG_CMD_MMC * MMC memory mapped support
883 CONFIG_CMD_MII * MII utility commands
884 CONFIG_CMD_MTDPARTS * MTD partition support
885 CONFIG_CMD_NAND * NAND support
886 CONFIG_CMD_NET bootp, tftpboot, rarpboot
887 CONFIG_CMD_NFS NFS support
888 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
889 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
890 CONFIG_CMD_PCI * pciinfo
891 CONFIG_CMD_PCMCIA * PCMCIA support
892 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
894 CONFIG_CMD_PORTIO * Port I/O
895 CONFIG_CMD_READ * Read raw data from partition
896 CONFIG_CMD_REGINFO * Register dump
897 CONFIG_CMD_RUN run command in env variable
898 CONFIG_CMD_SANDBOX * sb command to access sandbox features
899 CONFIG_CMD_SAVES * save S record dump
900 CONFIG_SCSI * SCSI Support
901 CONFIG_CMD_SDRAM * print SDRAM configuration information
902 (requires CONFIG_CMD_I2C)
903 CONFIG_CMD_SETGETDCR Support for DCR Register access
905 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
906 CONFIG_CMD_SHA1SUM * print sha1 memory digest
907 (requires CONFIG_CMD_MEMORY)
908 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
909 CONFIG_CMD_SOURCE "source" command Support
910 CONFIG_CMD_SPI * SPI serial bus support
911 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
912 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
913 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
914 CONFIG_CMD_TIMER * access to the system tick timer
915 CONFIG_CMD_USB * USB support
916 CONFIG_CMD_CDP * Cisco Discover Protocol support
917 CONFIG_CMD_MFSL * Microblaze FSL support
918 CONFIG_CMD_XIMG Load part of Multi Image
919 CONFIG_CMD_UUID * Generate random UUID or GUID string
921 EXAMPLE: If you want all functions except of network
922 support you can write:
924 #include "config_cmd_all.h"
925 #undef CONFIG_CMD_NET
928 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
930 Note: Don't enable the "icache" and "dcache" commands
931 (configuration option CONFIG_CMD_CACHE) unless you know
932 what you (and your U-Boot users) are doing. Data
933 cache cannot be enabled on systems like the 8xx or
934 8260 (where accesses to the IMMR region must be
935 uncached), and it cannot be disabled on all other
936 systems where we (mis-) use the data cache to hold an
937 initial stack and some data.
940 XXX - this list needs to get updated!
942 - Removal of commands
943 If no commands are needed to boot, you can disable
944 CONFIG_CMDLINE to remove them. In this case, the command line
945 will not be available, and when U-Boot wants to execute the
946 boot command (on start-up) it will call board_run_command()
947 instead. This can reduce image size significantly for very
948 simple boot procedures.
950 - Regular expression support:
952 If this variable is defined, U-Boot is linked against
953 the SLRE (Super Light Regular Expression) library,
954 which adds regex support to some commands, as for
955 example "env grep" and "setexpr".
959 If this variable is defined, U-Boot will use a device tree
960 to configure its devices, instead of relying on statically
961 compiled #defines in the board file. This option is
962 experimental and only available on a few boards. The device
963 tree is available in the global data as gd->fdt_blob.
965 U-Boot needs to get its device tree from somewhere. This can
966 be done using one of the three options below:
969 If this variable is defined, U-Boot will embed a device tree
970 binary in its image. This device tree file should be in the
971 board directory and called <soc>-<board>.dts. The binary file
972 is then picked up in board_init_f() and made available through
973 the global data structure as gd->blob.
976 If this variable is defined, U-Boot will build a device tree
977 binary. It will be called u-boot.dtb. Architecture-specific
978 code will locate it at run-time. Generally this works by:
980 cat u-boot.bin u-boot.dtb >image.bin
982 and in fact, U-Boot does this for you, creating a file called
983 u-boot-dtb.bin which is useful in the common case. You can
984 still use the individual files if you need something more
988 If this variable is defined, U-Boot will use the device tree
989 provided by the board at runtime instead of embedding one with
990 the image. Only boards defining board_fdt_blob_setup() support
991 this option (see include/fdtdec.h file).
995 If this variable is defined, it enables watchdog
996 support for the SoC. There must be support in the SoC
997 specific code for a watchdog. For the 8xx and 8260
998 CPUs, the SIU Watchdog feature is enabled in the SYPCR
999 register. When supported for a specific SoC is
1000 available, then no further board specific code should
1001 be needed to use it.
1004 When using a watchdog circuitry external to the used
1005 SoC, then define this variable and provide board
1006 specific code for the "hw_watchdog_reset" function.
1008 CONFIG_AT91_HW_WDT_TIMEOUT
1009 specify the timeout in seconds. default 2 seconds.
1012 CONFIG_VERSION_VARIABLE
1013 If this variable is defined, an environment variable
1014 named "ver" is created by U-Boot showing the U-Boot
1015 version as printed by the "version" command.
1016 Any change to this variable will be reverted at the
1021 When CONFIG_CMD_DATE is selected, the type of the RTC
1022 has to be selected, too. Define exactly one of the
1025 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1026 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1027 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1028 CONFIG_RTC_MC146818 - use MC146818 RTC
1029 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1030 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1031 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1032 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1033 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1034 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1035 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1036 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1037 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1040 Note that if the RTC uses I2C, then the I2C interface
1041 must also be configured. See I2C Support, below.
1044 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1046 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1047 chip-ngpio pairs that tell the PCA953X driver the number of
1048 pins supported by a particular chip.
1050 Note that if the GPIO device uses I2C, then the I2C interface
1051 must also be configured. See I2C Support, below.
1054 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1055 accesses and can checksum them or write a list of them out
1056 to memory. See the 'iotrace' command for details. This is
1057 useful for testing device drivers since it can confirm that
1058 the driver behaves the same way before and after a code
1059 change. Currently this is supported on sandbox and arm. To
1060 add support for your architecture, add '#include <iotrace.h>'
1061 to the bottom of arch/<arch>/include/asm/io.h and test.
1063 Example output from the 'iotrace stats' command is below.
1064 Note that if the trace buffer is exhausted, the checksum will
1065 still continue to operate.
1068 Start: 10000000 (buffer start address)
1069 Size: 00010000 (buffer size)
1070 Offset: 00000120 (current buffer offset)
1071 Output: 10000120 (start + offset)
1072 Count: 00000018 (number of trace records)
1073 CRC32: 9526fb66 (CRC32 of all trace records)
1075 - Timestamp Support:
1077 When CONFIG_TIMESTAMP is selected, the timestamp
1078 (date and time) of an image is printed by image
1079 commands like bootm or iminfo. This option is
1080 automatically enabled when you select CONFIG_CMD_DATE .
1082 - Partition Labels (disklabels) Supported:
1083 Zero or more of the following:
1084 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1085 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1086 Intel architecture, USB sticks, etc.
1087 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1088 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1089 bootloader. Note 2TB partition limit; see
1091 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1093 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1094 CONFIG_SCSI) you must configure support for at
1095 least one non-MTD partition type as well.
1098 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1099 board configurations files but used nowhere!
1101 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1102 be performed by calling the function
1103 ide_set_reset(int reset)
1104 which has to be defined in a board specific file
1109 Set this to enable ATAPI support.
1114 Set this to enable support for disks larger than 137GB
1115 Also look at CONFIG_SYS_64BIT_LBA.
1116 Whithout these , LBA48 support uses 32bit variables and will 'only'
1117 support disks up to 2.1TB.
1119 CONFIG_SYS_64BIT_LBA:
1120 When enabled, makes the IDE subsystem use 64bit sector addresses.
1124 At the moment only there is only support for the
1125 SYM53C8XX SCSI controller; define
1126 CONFIG_SCSI_SYM53C8XX to enable it.
1128 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1129 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1130 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1131 maximum numbers of LUNs, SCSI ID's and target
1133 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1135 The environment variable 'scsidevs' is set to the number of
1136 SCSI devices found during the last scan.
1138 - NETWORK Support (PCI):
1140 Support for Intel 8254x/8257x gigabit chips.
1143 Utility code for direct access to the SPI bus on Intel 8257x.
1144 This does not do anything useful unless you set at least one
1145 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1147 CONFIG_E1000_SPI_GENERIC
1148 Allow generic access to the SPI bus on the Intel 8257x, for
1149 example with the "sspi" command.
1152 Management command for E1000 devices. When used on devices
1153 with SPI support you can reprogram the EEPROM from U-Boot.
1156 Support for Intel 82557/82559/82559ER chips.
1157 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1158 write routine for first time initialisation.
1161 Support for Digital 2114x chips.
1162 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1163 modem chip initialisation (KS8761/QS6611).
1166 Support for National dp83815 chips.
1169 Support for National dp8382[01] gigabit chips.
1171 - NETWORK Support (other):
1173 CONFIG_DRIVER_AT91EMAC
1174 Support for AT91RM9200 EMAC.
1177 Define this to use reduced MII inteface
1179 CONFIG_DRIVER_AT91EMAC_QUIET
1180 If this defined, the driver is quiet.
1181 The driver doen't show link status messages.
1183 CONFIG_CALXEDA_XGMAC
1184 Support for the Calxeda XGMAC device
1187 Support for SMSC's LAN91C96 chips.
1189 CONFIG_LAN91C96_USE_32_BIT
1190 Define this to enable 32 bit addressing
1193 Support for SMSC's LAN91C111 chip
1195 CONFIG_SMC91111_BASE
1196 Define this to hold the physical address
1197 of the device (I/O space)
1199 CONFIG_SMC_USE_32_BIT
1200 Define this if data bus is 32 bits
1202 CONFIG_SMC_USE_IOFUNCS
1203 Define this to use i/o functions instead of macros
1204 (some hardware wont work with macros)
1206 CONFIG_DRIVER_TI_EMAC
1207 Support for davinci emac
1209 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1210 Define this if you have more then 3 PHYs.
1213 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1215 CONFIG_FTGMAC100_EGIGA
1216 Define this to use GE link update with gigabit PHY.
1217 Define this if FTGMAC100 is connected to gigabit PHY.
1218 If your system has 10/100 PHY only, it might not occur
1219 wrong behavior. Because PHY usually return timeout or
1220 useless data when polling gigabit status and gigabit
1221 control registers. This behavior won't affect the
1222 correctnessof 10/100 link speed update.
1225 Support for SMSC's LAN911x and LAN921x chips
1228 Define this to hold the physical address
1229 of the device (I/O space)
1231 CONFIG_SMC911X_32_BIT
1232 Define this if data bus is 32 bits
1234 CONFIG_SMC911X_16_BIT
1235 Define this if data bus is 16 bits. If your processor
1236 automatically converts one 32 bit word to two 16 bit
1237 words you may also try CONFIG_SMC911X_32_BIT.
1240 Support for Renesas on-chip Ethernet controller
1242 CONFIG_SH_ETHER_USE_PORT
1243 Define the number of ports to be used
1245 CONFIG_SH_ETHER_PHY_ADDR
1246 Define the ETH PHY's address
1248 CONFIG_SH_ETHER_CACHE_WRITEBACK
1249 If this option is set, the driver enables cache flush.
1253 Support for PWM module on the imx6.
1257 Support TPM devices.
1259 CONFIG_TPM_TIS_INFINEON
1260 Support for Infineon i2c bus TPM devices. Only one device
1261 per system is supported at this time.
1263 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1264 Define the burst count bytes upper limit
1267 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1269 CONFIG_TPM_ST33ZP24_I2C
1270 Support for STMicroelectronics ST33ZP24 I2C devices.
1271 Requires TPM_ST33ZP24 and I2C.
1273 CONFIG_TPM_ST33ZP24_SPI
1274 Support for STMicroelectronics ST33ZP24 SPI devices.
1275 Requires TPM_ST33ZP24 and SPI.
1277 CONFIG_TPM_ATMEL_TWI
1278 Support for Atmel TWI TPM device. Requires I2C support.
1281 Support for generic parallel port TPM devices. Only one device
1282 per system is supported at this time.
1284 CONFIG_TPM_TIS_BASE_ADDRESS
1285 Base address where the generic TPM device is mapped
1286 to. Contemporary x86 systems usually map it at
1290 Add tpm monitor functions.
1291 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1292 provides monitor access to authorized functions.
1295 Define this to enable the TPM support library which provides
1296 functional interfaces to some TPM commands.
1297 Requires support for a TPM device.
1299 CONFIG_TPM_AUTH_SESSIONS
1300 Define this to enable authorized functions in the TPM library.
1301 Requires CONFIG_TPM and CONFIG_SHA1.
1304 At the moment only the UHCI host controller is
1305 supported (PIP405, MIP405, MPC5200); define
1306 CONFIG_USB_UHCI to enable it.
1307 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1308 and define CONFIG_USB_STORAGE to enable the USB
1311 Supported are USB Keyboards and USB Floppy drives
1313 MPC5200 USB requires additional defines:
1315 for 528 MHz Clock: 0x0001bbbb
1319 for differential drivers: 0x00001000
1320 for single ended drivers: 0x00005000
1321 for differential drivers on PSC3: 0x00000100
1322 for single ended drivers on PSC3: 0x00004100
1323 CONFIG_SYS_USB_EVENT_POLL
1324 May be defined to allow interrupt polling
1325 instead of using asynchronous interrupts
1327 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1328 txfilltuning field in the EHCI controller on reset.
1330 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1331 HW module registers.
1334 Define the below if you wish to use the USB console.
1335 Once firmware is rebuilt from a serial console issue the
1336 command "setenv stdin usbtty; setenv stdout usbtty" and
1337 attach your USB cable. The Unix command "dmesg" should print
1338 it has found a new device. The environment variable usbtty
1339 can be set to gserial or cdc_acm to enable your device to
1340 appear to a USB host as a Linux gserial device or a
1341 Common Device Class Abstract Control Model serial device.
1342 If you select usbtty = gserial you should be able to enumerate
1344 # modprobe usbserial vendor=0xVendorID product=0xProductID
1345 else if using cdc_acm, simply setting the environment
1346 variable usbtty to be cdc_acm should suffice. The following
1347 might be defined in YourBoardName.h
1350 Define this to build a UDC device
1353 Define this to have a tty type of device available to
1354 talk to the UDC device
1357 Define this to enable the high speed support for usb
1358 device and usbtty. If this feature is enabled, a routine
1359 int is_usbd_high_speed(void)
1360 also needs to be defined by the driver to dynamically poll
1361 whether the enumeration has succeded at high speed or full
1364 CONFIG_SYS_CONSOLE_IS_IN_ENV
1365 Define this if you want stdin, stdout &/or stderr to
1369 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1370 Derive USB clock from external clock "blah"
1371 - CONFIG_SYS_USB_EXTC_CLK 0x02
1373 If you have a USB-IF assigned VendorID then you may wish to
1374 define your own vendor specific values either in BoardName.h
1375 or directly in usbd_vendor_info.h. If you don't define
1376 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1377 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1378 should pretend to be a Linux device to it's target host.
1380 CONFIG_USBD_MANUFACTURER
1381 Define this string as the name of your company for
1382 - CONFIG_USBD_MANUFACTURER "my company"
1384 CONFIG_USBD_PRODUCT_NAME
1385 Define this string as the name of your product
1386 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1388 CONFIG_USBD_VENDORID
1389 Define this as your assigned Vendor ID from the USB
1390 Implementors Forum. This *must* be a genuine Vendor ID
1391 to avoid polluting the USB namespace.
1392 - CONFIG_USBD_VENDORID 0xFFFF
1394 CONFIG_USBD_PRODUCTID
1395 Define this as the unique Product ID
1397 - CONFIG_USBD_PRODUCTID 0xFFFF
1399 - ULPI Layer Support:
1400 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1401 the generic ULPI layer. The generic layer accesses the ULPI PHY
1402 via the platform viewport, so you need both the genric layer and
1403 the viewport enabled. Currently only Chipidea/ARC based
1404 viewport is supported.
1405 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1406 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1407 If your ULPI phy needs a different reference clock than the
1408 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1409 the appropriate value in Hz.
1412 The MMC controller on the Intel PXA is supported. To
1413 enable this define CONFIG_MMC. The MMC can be
1414 accessed from the boot prompt by mapping the device
1415 to physical memory similar to flash. Command line is
1416 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1417 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1420 Support for Renesas on-chip MMCIF controller
1422 CONFIG_SH_MMCIF_ADDR
1423 Define the base address of MMCIF registers
1426 Define the clock frequency for MMCIF
1428 CONFIG_SUPPORT_EMMC_BOOT
1429 Enable some additional features of the eMMC boot partitions.
1431 CONFIG_SUPPORT_EMMC_RPMB
1432 Enable the commands for reading, writing and programming the
1433 key for the Replay Protection Memory Block partition in eMMC.
1435 - USB Device Firmware Update (DFU) class support:
1436 CONFIG_USB_FUNCTION_DFU
1437 This enables the USB portion of the DFU USB class
1440 This enables the command "dfu" which is used to have
1441 U-Boot create a DFU class device via USB. This command
1442 requires that the "dfu_alt_info" environment variable be
1443 set and define the alt settings to expose to the host.
1446 This enables support for exposing (e)MMC devices via DFU.
1449 This enables support for exposing NAND devices via DFU.
1452 This enables support for exposing RAM via DFU.
1453 Note: DFU spec refer to non-volatile memory usage, but
1454 allow usages beyond the scope of spec - here RAM usage,
1455 one that would help mostly the developer.
1457 CONFIG_SYS_DFU_DATA_BUF_SIZE
1458 Dfu transfer uses a buffer before writing data to the
1459 raw storage device. Make the size (in bytes) of this buffer
1460 configurable. The size of this buffer is also configurable
1461 through the "dfu_bufsiz" environment variable.
1463 CONFIG_SYS_DFU_MAX_FILE_SIZE
1464 When updating files rather than the raw storage device,
1465 we use a static buffer to copy the file into and then write
1466 the buffer once we've been given the whole file. Define
1467 this to the maximum filesize (in bytes) for the buffer.
1468 Default is 4 MiB if undefined.
1470 DFU_DEFAULT_POLL_TIMEOUT
1471 Poll timeout [ms], is the timeout a device can send to the
1472 host. The host must wait for this timeout before sending
1473 a subsequent DFU_GET_STATUS request to the device.
1475 DFU_MANIFEST_POLL_TIMEOUT
1476 Poll timeout [ms], which the device sends to the host when
1477 entering dfuMANIFEST state. Host waits this timeout, before
1478 sending again an USB request to the device.
1480 - USB Device Android Fastboot support:
1481 CONFIG_USB_FUNCTION_FASTBOOT
1482 This enables the USB part of the fastboot gadget
1485 This enables the command "fastboot" which enables the Android
1486 fastboot mode for the platform's USB device. Fastboot is a USB
1487 protocol for downloading images, flashing and device control
1488 used on Android devices.
1489 See doc/README.android-fastboot for more information.
1491 CONFIG_ANDROID_BOOT_IMAGE
1492 This enables support for booting images which use the Android
1493 image format header.
1495 CONFIG_FASTBOOT_BUF_ADDR
1496 The fastboot protocol requires a large memory buffer for
1497 downloads. Define this to the starting RAM address to use for
1500 CONFIG_FASTBOOT_BUF_SIZE
1501 The fastboot protocol requires a large memory buffer for
1502 downloads. This buffer should be as large as possible for a
1503 platform. Define this to the size available RAM for fastboot.
1505 CONFIG_FASTBOOT_FLASH
1506 The fastboot protocol includes a "flash" command for writing
1507 the downloaded image to a non-volatile storage device. Define
1508 this to enable the "fastboot flash" command.
1510 CONFIG_FASTBOOT_FLASH_MMC_DEV
1511 The fastboot "flash" command requires additional information
1512 regarding the non-volatile storage device. Define this to
1513 the eMMC device that fastboot should use to store the image.
1515 CONFIG_FASTBOOT_GPT_NAME
1516 The fastboot "flash" command supports writing the downloaded
1517 image to the Protective MBR and the Primary GUID Partition
1518 Table. (Additionally, this downloaded image is post-processed
1519 to generate and write the Backup GUID Partition Table.)
1520 This occurs when the specified "partition name" on the
1521 "fastboot flash" command line matches this value.
1522 The default is "gpt" if undefined.
1524 CONFIG_FASTBOOT_MBR_NAME
1525 The fastboot "flash" command supports writing the downloaded
1527 This occurs when the "partition name" specified on the
1528 "fastboot flash" command line matches this value.
1529 If not defined the default value "mbr" is used.
1531 - Journaling Flash filesystem support:
1533 Define these for a default partition on a NAND device
1535 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1536 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1537 Define these for a default partition on a NOR device
1539 - FAT(File Allocation Table) filesystem write function support:
1542 Define this to enable support for saving memory data as a
1543 file in FAT formatted partition.
1545 This will also enable the command "fatwrite" enabling the
1546 user to write files to FAT.
1548 - FAT(File Allocation Table) filesystem cluster size:
1549 CONFIG_FS_FAT_MAX_CLUSTSIZE
1551 Define the max cluster size for fat operations else
1552 a default value of 65536 will be defined.
1555 See Kconfig help for available keyboard drivers.
1559 Define this to enable a custom keyboard support.
1560 This simply calls drv_keyboard_init() which must be
1561 defined in your board-specific files. This option is deprecated
1562 and is only used by novena. For new boards, use driver model
1567 Enable the Freescale DIU video driver. Reference boards for
1568 SOCs that have a DIU should define this macro to enable DIU
1569 support, and should also define these other macros:
1574 CONFIG_VIDEO_SW_CURSOR
1575 CONFIG_VGA_AS_SINGLE_DEVICE
1577 CONFIG_VIDEO_BMP_LOGO
1579 The DIU driver will look for the 'video-mode' environment
1580 variable, and if defined, enable the DIU as a console during
1581 boot. See the documentation file doc/README.video for a
1582 description of this variable.
1584 - LCD Support: CONFIG_LCD
1586 Define this to enable LCD support (for output to LCD
1587 display); also select one of the supported displays
1588 by defining one of these:
1592 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1594 CONFIG_NEC_NL6448AC33:
1596 NEC NL6448AC33-18. Active, color, single scan.
1598 CONFIG_NEC_NL6448BC20
1600 NEC NL6448BC20-08. 6.5", 640x480.
1601 Active, color, single scan.
1603 CONFIG_NEC_NL6448BC33_54
1605 NEC NL6448BC33-54. 10.4", 640x480.
1606 Active, color, single scan.
1610 Sharp 320x240. Active, color, single scan.
1611 It isn't 16x9, and I am not sure what it is.
1613 CONFIG_SHARP_LQ64D341
1615 Sharp LQ64D341 display, 640x480.
1616 Active, color, single scan.
1620 HLD1045 display, 640x480.
1621 Active, color, single scan.
1625 Optrex CBL50840-2 NF-FW 99 22 M5
1627 Hitachi LMG6912RPFC-00T
1631 320x240. Black & white.
1633 CONFIG_LCD_ALIGNMENT
1635 Normally the LCD is page-aligned (typically 4KB). If this is
1636 defined then the LCD will be aligned to this value instead.
1637 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1638 here, since it is cheaper to change data cache settings on
1639 a per-section basis.
1644 Sometimes, for example if the display is mounted in portrait
1645 mode or even if it's mounted landscape but rotated by 180degree,
1646 we need to rotate our content of the display relative to the
1647 framebuffer, so that user can read the messages which are
1649 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1650 initialized with a given rotation from "vl_rot" out of
1651 "vidinfo_t" which is provided by the board specific code.
1652 The value for vl_rot is coded as following (matching to
1653 fbcon=rotate:<n> linux-kernel commandline):
1654 0 = no rotation respectively 0 degree
1655 1 = 90 degree rotation
1656 2 = 180 degree rotation
1657 3 = 270 degree rotation
1659 If CONFIG_LCD_ROTATION is not defined, the console will be
1660 initialized with 0degree rotation.
1664 Support drawing of RLE8-compressed bitmaps on the LCD.
1668 Enables an 'i2c edid' command which can read EDID
1669 information over I2C from an attached LCD display.
1671 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1673 If this option is set, the environment is checked for
1674 a variable "splashimage". If found, the usual display
1675 of logo, copyright and system information on the LCD
1676 is suppressed and the BMP image at the address
1677 specified in "splashimage" is loaded instead. The
1678 console is redirected to the "nulldev", too. This
1679 allows for a "silent" boot where a splash screen is
1680 loaded very quickly after power-on.
1682 CONFIG_SPLASHIMAGE_GUARD
1684 If this option is set, then U-Boot will prevent the environment
1685 variable "splashimage" from being set to a problematic address
1686 (see doc/README.displaying-bmps).
1687 This option is useful for targets where, due to alignment
1688 restrictions, an improperly aligned BMP image will cause a data
1689 abort. If you think you will not have problems with unaligned
1690 accesses (for example because your toolchain prevents them)
1691 there is no need to set this option.
1693 CONFIG_SPLASH_SCREEN_ALIGN
1695 If this option is set the splash image can be freely positioned
1696 on the screen. Environment variable "splashpos" specifies the
1697 position as "x,y". If a positive number is given it is used as
1698 number of pixel from left/top. If a negative number is given it
1699 is used as number of pixel from right/bottom. You can also
1700 specify 'm' for centering the image.
1703 setenv splashpos m,m
1704 => image at center of screen
1706 setenv splashpos 30,20
1707 => image at x = 30 and y = 20
1709 setenv splashpos -10,m
1710 => vertically centered image
1711 at x = dspWidth - bmpWidth - 9
1713 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1715 If this option is set, additionally to standard BMP
1716 images, gzipped BMP images can be displayed via the
1717 splashscreen support or the bmp command.
1719 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1721 If this option is set, 8-bit RLE compressed BMP images
1722 can be displayed via the splashscreen support or the
1725 - Compression support:
1728 Enabled by default to support gzip compressed images.
1732 If this option is set, support for bzip2 compressed
1733 images is included. If not, only uncompressed and gzip
1734 compressed images are supported.
1736 NOTE: the bzip2 algorithm requires a lot of RAM, so
1737 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1742 If this option is set, support for lzma compressed
1745 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1746 requires an amount of dynamic memory that is given by the
1749 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1751 Where lc and lp stand for, respectively, Literal context bits
1752 and Literal pos bits.
1754 This value is upper-bounded by 14MB in the worst case. Anyway,
1755 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1756 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1757 a very small buffer.
1759 Use the lzmainfo tool to determinate the lc and lp values and
1760 then calculate the amount of needed dynamic memory (ensuring
1761 the appropriate CONFIG_SYS_MALLOC_LEN value).
1765 If this option is set, support for LZO compressed images
1771 The address of PHY on MII bus.
1773 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1775 The clock frequency of the MII bus
1779 If this option is set, support for speed/duplex
1780 detection of gigabit PHY is included.
1782 CONFIG_PHY_RESET_DELAY
1784 Some PHY like Intel LXT971A need extra delay after
1785 reset before any MII register access is possible.
1786 For such PHY, set this option to the usec delay
1787 required. (minimum 300usec for LXT971A)
1789 CONFIG_PHY_CMD_DELAY (ppc4xx)
1791 Some PHY like Intel LXT971A need extra delay after
1792 command issued before MII status register can be read
1797 Define a default value for the IP address to use for
1798 the default Ethernet interface, in case this is not
1799 determined through e.g. bootp.
1800 (Environment variable "ipaddr")
1802 - Server IP address:
1805 Defines a default value for the IP address of a TFTP
1806 server to contact when using the "tftboot" command.
1807 (Environment variable "serverip")
1809 CONFIG_KEEP_SERVERADDR
1811 Keeps the server's MAC address, in the env 'serveraddr'
1812 for passing to bootargs (like Linux's netconsole option)
1814 - Gateway IP address:
1817 Defines a default value for the IP address of the
1818 default router where packets to other networks are
1820 (Environment variable "gatewayip")
1825 Defines a default value for the subnet mask (or
1826 routing prefix) which is used to determine if an IP
1827 address belongs to the local subnet or needs to be
1828 forwarded through a router.
1829 (Environment variable "netmask")
1831 - Multicast TFTP Mode:
1834 Defines whether you want to support multicast TFTP as per
1835 rfc-2090; for example to work with atftp. Lets lots of targets
1836 tftp down the same boot image concurrently. Note: the Ethernet
1837 driver in use must provide a function: mcast() to join/leave a
1840 - BOOTP Recovery Mode:
1841 CONFIG_BOOTP_RANDOM_DELAY
1843 If you have many targets in a network that try to
1844 boot using BOOTP, you may want to avoid that all
1845 systems send out BOOTP requests at precisely the same
1846 moment (which would happen for instance at recovery
1847 from a power failure, when all systems will try to
1848 boot, thus flooding the BOOTP server. Defining
1849 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1850 inserted before sending out BOOTP requests. The
1851 following delays are inserted then:
1853 1st BOOTP request: delay 0 ... 1 sec
1854 2nd BOOTP request: delay 0 ... 2 sec
1855 3rd BOOTP request: delay 0 ... 4 sec
1857 BOOTP requests: delay 0 ... 8 sec
1859 CONFIG_BOOTP_ID_CACHE_SIZE
1861 BOOTP packets are uniquely identified using a 32-bit ID. The
1862 server will copy the ID from client requests to responses and
1863 U-Boot will use this to determine if it is the destination of
1864 an incoming response. Some servers will check that addresses
1865 aren't in use before handing them out (usually using an ARP
1866 ping) and therefore take up to a few hundred milliseconds to
1867 respond. Network congestion may also influence the time it
1868 takes for a response to make it back to the client. If that
1869 time is too long, U-Boot will retransmit requests. In order
1870 to allow earlier responses to still be accepted after these
1871 retransmissions, U-Boot's BOOTP client keeps a small cache of
1872 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1873 cache. The default is to keep IDs for up to four outstanding
1874 requests. Increasing this will allow U-Boot to accept offers
1875 from a BOOTP client in networks with unusually high latency.
1877 - DHCP Advanced Options:
1878 You can fine tune the DHCP functionality by defining
1879 CONFIG_BOOTP_* symbols:
1881 CONFIG_BOOTP_SUBNETMASK
1882 CONFIG_BOOTP_GATEWAY
1883 CONFIG_BOOTP_HOSTNAME
1884 CONFIG_BOOTP_NISDOMAIN
1885 CONFIG_BOOTP_BOOTPATH
1886 CONFIG_BOOTP_BOOTFILESIZE
1889 CONFIG_BOOTP_SEND_HOSTNAME
1890 CONFIG_BOOTP_NTPSERVER
1891 CONFIG_BOOTP_TIMEOFFSET
1892 CONFIG_BOOTP_VENDOREX
1893 CONFIG_BOOTP_MAY_FAIL
1895 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1896 environment variable, not the BOOTP server.
1898 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1899 after the configured retry count, the call will fail
1900 instead of starting over. This can be used to fail over
1901 to Link-local IP address configuration if the DHCP server
1904 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1905 serverip from a DHCP server, it is possible that more
1906 than one DNS serverip is offered to the client.
1907 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1908 serverip will be stored in the additional environment
1909 variable "dnsip2". The first DNS serverip is always
1910 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1913 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1914 to do a dynamic update of a DNS server. To do this, they
1915 need the hostname of the DHCP requester.
1916 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1917 of the "hostname" environment variable is passed as
1918 option 12 to the DHCP server.
1920 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1922 A 32bit value in microseconds for a delay between
1923 receiving a "DHCP Offer" and sending the "DHCP Request".
1924 This fixes a problem with certain DHCP servers that don't
1925 respond 100% of the time to a "DHCP request". E.g. On an
1926 AT91RM9200 processor running at 180MHz, this delay needed
1927 to be *at least* 15,000 usec before a Windows Server 2003
1928 DHCP server would reply 100% of the time. I recommend at
1929 least 50,000 usec to be safe. The alternative is to hope
1930 that one of the retries will be successful but note that
1931 the DHCP timeout and retry process takes a longer than
1934 - Link-local IP address negotiation:
1935 Negotiate with other link-local clients on the local network
1936 for an address that doesn't require explicit configuration.
1937 This is especially useful if a DHCP server cannot be guaranteed
1938 to exist in all environments that the device must operate.
1940 See doc/README.link-local for more information.
1943 CONFIG_CDP_DEVICE_ID
1945 The device id used in CDP trigger frames.
1947 CONFIG_CDP_DEVICE_ID_PREFIX
1949 A two character string which is prefixed to the MAC address
1954 A printf format string which contains the ascii name of
1955 the port. Normally is set to "eth%d" which sets
1956 eth0 for the first Ethernet, eth1 for the second etc.
1958 CONFIG_CDP_CAPABILITIES
1960 A 32bit integer which indicates the device capabilities;
1961 0x00000010 for a normal host which does not forwards.
1965 An ascii string containing the version of the software.
1969 An ascii string containing the name of the platform.
1973 A 32bit integer sent on the trigger.
1975 CONFIG_CDP_POWER_CONSUMPTION
1977 A 16bit integer containing the power consumption of the
1978 device in .1 of milliwatts.
1980 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1982 A byte containing the id of the VLAN.
1984 - Status LED: CONFIG_LED_STATUS
1986 Several configurations allow to display the current
1987 status using a LED. For instance, the LED will blink
1988 fast while running U-Boot code, stop blinking as
1989 soon as a reply to a BOOTP request was received, and
1990 start blinking slow once the Linux kernel is running
1991 (supported by a status LED driver in the Linux
1992 kernel). Defining CONFIG_LED_STATUS enables this
1997 CONFIG_LED_STATUS_GPIO
1998 The status LED can be connected to a GPIO pin.
1999 In such cases, the gpio_led driver can be used as a
2000 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2001 to include the gpio_led driver in the U-Boot binary.
2003 CONFIG_GPIO_LED_INVERTED_TABLE
2004 Some GPIO connected LEDs may have inverted polarity in which
2005 case the GPIO high value corresponds to LED off state and
2006 GPIO low value corresponds to LED on state.
2007 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2008 with a list of GPIO LEDs that have inverted polarity.
2010 - CAN Support: CONFIG_CAN_DRIVER
2012 Defining CONFIG_CAN_DRIVER enables CAN driver support
2013 on those systems that support this (optional)
2014 feature, like the TQM8xxL modules.
2016 - I2C Support: CONFIG_SYS_I2C
2018 This enable the NEW i2c subsystem, and will allow you to use
2019 i2c commands at the u-boot command line (as long as you set
2020 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2021 based realtime clock chips or other i2c devices. See
2022 common/cmd_i2c.c for a description of the command line
2025 ported i2c driver to the new framework:
2026 - drivers/i2c/soft_i2c.c:
2027 - activate first bus with CONFIG_SYS_I2C_SOFT define
2028 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2029 for defining speed and slave address
2030 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2031 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2032 for defining speed and slave address
2033 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2034 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2035 for defining speed and slave address
2036 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2037 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2038 for defining speed and slave address
2040 - drivers/i2c/fsl_i2c.c:
2041 - activate i2c driver with CONFIG_SYS_I2C_FSL
2042 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2043 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2044 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2046 - If your board supports a second fsl i2c bus, define
2047 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2048 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2049 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2052 - drivers/i2c/tegra_i2c.c:
2053 - activate this driver with CONFIG_SYS_I2C_TEGRA
2054 - This driver adds 4 i2c buses with a fix speed from
2055 100000 and the slave addr 0!
2057 - drivers/i2c/ppc4xx_i2c.c
2058 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2059 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2060 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2062 - drivers/i2c/i2c_mxc.c
2063 - activate this driver with CONFIG_SYS_I2C_MXC
2064 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2065 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2066 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2067 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2068 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2069 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2070 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2071 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2072 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2073 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2074 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2075 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2076 If those defines are not set, default value is 100000
2077 for speed, and 0 for slave.
2079 - drivers/i2c/rcar_i2c.c:
2080 - activate this driver with CONFIG_SYS_I2C_RCAR
2081 - This driver adds 4 i2c buses
2083 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2084 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2085 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2086 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2087 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2088 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2089 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2090 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2091 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2093 - drivers/i2c/sh_i2c.c:
2094 - activate this driver with CONFIG_SYS_I2C_SH
2095 - This driver adds from 2 to 5 i2c buses
2097 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2098 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2099 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2100 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2101 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2102 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2103 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2104 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2105 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2106 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2107 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2109 - drivers/i2c/omap24xx_i2c.c
2110 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2111 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2112 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2113 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2114 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2115 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2116 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2117 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2118 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2119 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2120 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2122 - drivers/i2c/zynq_i2c.c
2123 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2124 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2125 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2127 - drivers/i2c/s3c24x0_i2c.c:
2128 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2129 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2130 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2131 with a fix speed from 100000 and the slave addr 0!
2133 - drivers/i2c/ihs_i2c.c
2134 - activate this driver with CONFIG_SYS_I2C_IHS
2135 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2136 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2137 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2138 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2139 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2140 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2141 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2142 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2143 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2144 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2145 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2146 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2147 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2148 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2149 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2150 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2151 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2152 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2153 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2154 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2155 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2159 CONFIG_SYS_NUM_I2C_BUSES
2160 Hold the number of i2c buses you want to use.
2162 CONFIG_SYS_I2C_DIRECT_BUS
2163 define this, if you don't use i2c muxes on your hardware.
2164 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2167 CONFIG_SYS_I2C_MAX_HOPS
2168 define how many muxes are maximal consecutively connected
2169 on one i2c bus. If you not use i2c muxes, omit this
2172 CONFIG_SYS_I2C_BUSES
2173 hold a list of buses you want to use, only used if
2174 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2175 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2176 CONFIG_SYS_NUM_I2C_BUSES = 9:
2178 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2179 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2180 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2181 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2182 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2183 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2184 {1, {I2C_NULL_HOP}}, \
2185 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2186 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2190 bus 0 on adapter 0 without a mux
2191 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2192 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2193 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2194 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2195 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2196 bus 6 on adapter 1 without a mux
2197 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2198 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2200 If you do not have i2c muxes on your board, omit this define.
2202 - Legacy I2C Support:
2203 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2204 then the following macros need to be defined (examples are
2205 from include/configs/lwmon.h):
2209 (Optional). Any commands necessary to enable the I2C
2210 controller or configure ports.
2212 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2216 (Only for MPC8260 CPU). The I/O port to use (the code
2217 assumes both bits are on the same port). Valid values
2218 are 0..3 for ports A..D.
2222 The code necessary to make the I2C data line active
2223 (driven). If the data line is open collector, this
2226 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2230 The code necessary to make the I2C data line tri-stated
2231 (inactive). If the data line is open collector, this
2234 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2238 Code that returns true if the I2C data line is high,
2241 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2245 If <bit> is true, sets the I2C data line high. If it
2246 is false, it clears it (low).
2248 eg: #define I2C_SDA(bit) \
2249 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2250 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2254 If <bit> is true, sets the I2C clock line high. If it
2255 is false, it clears it (low).
2257 eg: #define I2C_SCL(bit) \
2258 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2259 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2263 This delay is invoked four times per clock cycle so this
2264 controls the rate of data transfer. The data rate thus
2265 is 1 / (I2C_DELAY * 4). Often defined to be something
2268 #define I2C_DELAY udelay(2)
2270 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2272 If your arch supports the generic GPIO framework (asm/gpio.h),
2273 then you may alternatively define the two GPIOs that are to be
2274 used as SCL / SDA. Any of the previous I2C_xxx macros will
2275 have GPIO-based defaults assigned to them as appropriate.
2277 You should define these to the GPIO value as given directly to
2278 the generic GPIO functions.
2280 CONFIG_SYS_I2C_INIT_BOARD
2282 When a board is reset during an i2c bus transfer
2283 chips might think that the current transfer is still
2284 in progress. On some boards it is possible to access
2285 the i2c SCLK line directly, either by using the
2286 processor pin as a GPIO or by having a second pin
2287 connected to the bus. If this option is defined a
2288 custom i2c_init_board() routine in boards/xxx/board.c
2289 is run early in the boot sequence.
2291 CONFIG_I2C_MULTI_BUS
2293 This option allows the use of multiple I2C buses, each of which
2294 must have a controller. At any point in time, only one bus is
2295 active. To switch to a different bus, use the 'i2c dev' command.
2296 Note that bus numbering is zero-based.
2298 CONFIG_SYS_I2C_NOPROBES
2300 This option specifies a list of I2C devices that will be skipped
2301 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2302 is set, specify a list of bus-device pairs. Otherwise, specify
2303 a 1D array of device addresses
2306 #undef CONFIG_I2C_MULTI_BUS
2307 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2309 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2311 #define CONFIG_I2C_MULTI_BUS
2312 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2314 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2316 CONFIG_SYS_SPD_BUS_NUM
2318 If defined, then this indicates the I2C bus number for DDR SPD.
2319 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2321 CONFIG_SYS_RTC_BUS_NUM
2323 If defined, then this indicates the I2C bus number for the RTC.
2324 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2326 CONFIG_SOFT_I2C_READ_REPEATED_START
2328 defining this will force the i2c_read() function in
2329 the soft_i2c driver to perform an I2C repeated start
2330 between writing the address pointer and reading the
2331 data. If this define is omitted the default behaviour
2332 of doing a stop-start sequence will be used. Most I2C
2333 devices can use either method, but some require one or
2336 - SPI Support: CONFIG_SPI
2338 Enables SPI driver (so far only tested with
2339 SPI EEPROM, also an instance works with Crystal A/D and
2340 D/As on the SACSng board)
2344 Enables the driver for SPI controller on SuperH. Currently
2345 only SH7757 is supported.
2349 Enables a software (bit-bang) SPI driver rather than
2350 using hardware support. This is a general purpose
2351 driver that only requires three general I/O port pins
2352 (two outputs, one input) to function. If this is
2353 defined, the board configuration must define several
2354 SPI configuration items (port pins to use, etc). For
2355 an example, see include/configs/sacsng.h.
2359 Enables a hardware SPI driver for general-purpose reads
2360 and writes. As with CONFIG_SOFT_SPI, the board configuration
2361 must define a list of chip-select function pointers.
2362 Currently supported on some MPC8xxx processors. For an
2363 example, see include/configs/mpc8349emds.h.
2367 Enables the driver for the SPI controllers on i.MX and MXC
2368 SoCs. Currently i.MX31/35/51 are supported.
2370 CONFIG_SYS_SPI_MXC_WAIT
2371 Timeout for waiting until spi transfer completed.
2372 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2374 - FPGA Support: CONFIG_FPGA
2376 Enables FPGA subsystem.
2378 CONFIG_FPGA_<vendor>
2380 Enables support for specific chip vendors.
2383 CONFIG_FPGA_<family>
2385 Enables support for FPGA family.
2386 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2390 Specify the number of FPGA devices to support.
2392 CONFIG_CMD_FPGA_LOADMK
2394 Enable support for fpga loadmk command
2396 CONFIG_CMD_FPGA_LOADP
2398 Enable support for fpga loadp command - load partial bitstream
2400 CONFIG_CMD_FPGA_LOADBP
2402 Enable support for fpga loadbp command - load partial bitstream
2405 CONFIG_SYS_FPGA_PROG_FEEDBACK
2407 Enable printing of hash marks during FPGA configuration.
2409 CONFIG_SYS_FPGA_CHECK_BUSY
2411 Enable checks on FPGA configuration interface busy
2412 status by the configuration function. This option
2413 will require a board or device specific function to
2418 If defined, a function that provides delays in the FPGA
2419 configuration driver.
2421 CONFIG_SYS_FPGA_CHECK_CTRLC
2422 Allow Control-C to interrupt FPGA configuration
2424 CONFIG_SYS_FPGA_CHECK_ERROR
2426 Check for configuration errors during FPGA bitfile
2427 loading. For example, abort during Virtex II
2428 configuration if the INIT_B line goes low (which
2429 indicated a CRC error).
2431 CONFIG_SYS_FPGA_WAIT_INIT
2433 Maximum time to wait for the INIT_B line to de-assert
2434 after PROB_B has been de-asserted during a Virtex II
2435 FPGA configuration sequence. The default time is 500
2438 CONFIG_SYS_FPGA_WAIT_BUSY
2440 Maximum time to wait for BUSY to de-assert during
2441 Virtex II FPGA configuration. The default is 5 ms.
2443 CONFIG_SYS_FPGA_WAIT_CONFIG
2445 Time to wait after FPGA configuration. The default is
2448 - Configuration Management:
2451 Some SoCs need special image types (e.g. U-Boot binary
2452 with a special header) as build targets. By defining
2453 CONFIG_BUILD_TARGET in the SoC / board header, this
2454 special image will be automatically built upon calling
2459 If defined, this string will be added to the U-Boot
2460 version information (U_BOOT_VERSION)
2462 - Vendor Parameter Protection:
2464 U-Boot considers the values of the environment
2465 variables "serial#" (Board Serial Number) and
2466 "ethaddr" (Ethernet Address) to be parameters that
2467 are set once by the board vendor / manufacturer, and
2468 protects these variables from casual modification by
2469 the user. Once set, these variables are read-only,
2470 and write or delete attempts are rejected. You can
2471 change this behaviour:
2473 If CONFIG_ENV_OVERWRITE is #defined in your config
2474 file, the write protection for vendor parameters is
2475 completely disabled. Anybody can change or delete
2478 Alternatively, if you define _both_ an ethaddr in the
2479 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2480 Ethernet address is installed in the environment,
2481 which can be changed exactly ONCE by the user. [The
2482 serial# is unaffected by this, i. e. it remains
2485 The same can be accomplished in a more flexible way
2486 for any variable by configuring the type of access
2487 to allow for those variables in the ".flags" variable
2488 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2493 Define this variable to enable the reservation of
2494 "protected RAM", i. e. RAM which is not overwritten
2495 by U-Boot. Define CONFIG_PRAM to hold the number of
2496 kB you want to reserve for pRAM. You can overwrite
2497 this default value by defining an environment
2498 variable "pram" to the number of kB you want to
2499 reserve. Note that the board info structure will
2500 still show the full amount of RAM. If pRAM is
2501 reserved, a new environment variable "mem" will
2502 automatically be defined to hold the amount of
2503 remaining RAM in a form that can be passed as boot
2504 argument to Linux, for instance like that:
2506 setenv bootargs ... mem=\${mem}
2509 This way you can tell Linux not to use this memory,
2510 either, which results in a memory region that will
2511 not be affected by reboots.
2513 *WARNING* If your board configuration uses automatic
2514 detection of the RAM size, you must make sure that
2515 this memory test is non-destructive. So far, the
2516 following board configurations are known to be
2519 IVMS8, IVML24, SPD8xx, TQM8xxL,
2520 HERMES, IP860, RPXlite, LWMON,
2523 - Access to physical memory region (> 4GB)
2524 Some basic support is provided for operations on memory not
2525 normally accessible to U-Boot - e.g. some architectures
2526 support access to more than 4GB of memory on 32-bit
2527 machines using physical address extension or similar.
2528 Define CONFIG_PHYSMEM to access this basic support, which
2529 currently only supports clearing the memory.
2534 Define this variable to stop the system in case of a
2535 fatal error, so that you have to reset it manually.
2536 This is probably NOT a good idea for an embedded
2537 system where you want the system to reboot
2538 automatically as fast as possible, but it may be
2539 useful during development since you can try to debug
2540 the conditions that lead to the situation.
2542 CONFIG_NET_RETRY_COUNT
2544 This variable defines the number of retries for
2545 network operations like ARP, RARP, TFTP, or BOOTP
2546 before giving up the operation. If not defined, a
2547 default value of 5 is used.
2551 Timeout waiting for an ARP reply in milliseconds.
2555 Timeout in milliseconds used in NFS protocol.
2556 If you encounter "ERROR: Cannot umount" in nfs command,
2557 try longer timeout such as
2558 #define CONFIG_NFS_TIMEOUT 10000UL
2560 - Command Interpreter:
2561 CONFIG_AUTO_COMPLETE
2563 Enable auto completion of commands using TAB.
2565 CONFIG_SYS_PROMPT_HUSH_PS2
2567 This defines the secondary prompt string, which is
2568 printed when the command interpreter needs more input
2569 to complete a command. Usually "> ".
2573 In the current implementation, the local variables
2574 space and global environment variables space are
2575 separated. Local variables are those you define by
2576 simply typing `name=value'. To access a local
2577 variable later on, you have write `$name' or
2578 `${name}'; to execute the contents of a variable
2579 directly type `$name' at the command prompt.
2581 Global environment variables are those you use
2582 setenv/printenv to work with. To run a command stored
2583 in such a variable, you need to use the run command,
2584 and you must not use the '$' sign to access them.
2586 To store commands and special characters in a
2587 variable, please use double quotation marks
2588 surrounding the whole text of the variable, instead
2589 of the backslashes before semicolons and special
2592 - Command Line Editing and History:
2593 CONFIG_CMDLINE_EDITING
2595 Enable editing and History functions for interactive
2596 command line input operations
2598 - Command Line PS1/PS2 support:
2599 CONFIG_CMDLINE_PS_SUPPORT
2601 Enable support for changing the command prompt string
2602 at run-time. Only static string is supported so far.
2603 The string is obtained from environment variables PS1
2606 - Default Environment:
2607 CONFIG_EXTRA_ENV_SETTINGS
2609 Define this to contain any number of null terminated
2610 strings (variable = value pairs) that will be part of
2611 the default environment compiled into the boot image.
2613 For example, place something like this in your
2614 board's config file:
2616 #define CONFIG_EXTRA_ENV_SETTINGS \
2620 Warning: This method is based on knowledge about the
2621 internal format how the environment is stored by the
2622 U-Boot code. This is NOT an official, exported
2623 interface! Although it is unlikely that this format
2624 will change soon, there is no guarantee either.
2625 You better know what you are doing here.
2627 Note: overly (ab)use of the default environment is
2628 discouraged. Make sure to check other ways to preset
2629 the environment like the "source" command or the
2632 CONFIG_ENV_VARS_UBOOT_CONFIG
2634 Define this in order to add variables describing the
2635 U-Boot build configuration to the default environment.
2636 These will be named arch, cpu, board, vendor, and soc.
2638 Enabling this option will cause the following to be defined:
2646 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2648 Define this in order to add variables describing certain
2649 run-time determined information about the hardware to the
2650 environment. These will be named board_name, board_rev.
2652 CONFIG_DELAY_ENVIRONMENT
2654 Normally the environment is loaded when the board is
2655 initialised so that it is available to U-Boot. This inhibits
2656 that so that the environment is not available until
2657 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2658 this is instead controlled by the value of
2659 /config/load-environment.
2661 - DataFlash Support:
2662 CONFIG_HAS_DATAFLASH
2664 Defining this option enables DataFlash features and
2665 allows to read/write in Dataflash via the standard
2668 - Serial Flash support
2671 Defining this option enables SPI flash commands
2672 'sf probe/read/write/erase/update'.
2674 Usage requires an initial 'probe' to define the serial
2675 flash parameters, followed by read/write/erase/update
2678 The following defaults may be provided by the platform
2679 to handle the common case when only a single serial
2680 flash is present on the system.
2682 CONFIG_SF_DEFAULT_BUS Bus identifier
2683 CONFIG_SF_DEFAULT_CS Chip-select
2684 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2685 CONFIG_SF_DEFAULT_SPEED in Hz
2689 Define this option to include a destructive SPI flash
2692 CONFIG_SF_DUAL_FLASH Dual flash memories
2694 Define this option to use dual flash support where two flash
2695 memories can be connected with a given cs line.
2696 Currently Xilinx Zynq qspi supports these type of connections.
2698 - SystemACE Support:
2701 Adding this option adds support for Xilinx SystemACE
2702 chips attached via some sort of local bus. The address
2703 of the chip must also be defined in the
2704 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2706 #define CONFIG_SYSTEMACE
2707 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2709 When SystemACE support is added, the "ace" device type
2710 becomes available to the fat commands, i.e. fatls.
2712 - TFTP Fixed UDP Port:
2715 If this is defined, the environment variable tftpsrcp
2716 is used to supply the TFTP UDP source port value.
2717 If tftpsrcp isn't defined, the normal pseudo-random port
2718 number generator is used.
2720 Also, the environment variable tftpdstp is used to supply
2721 the TFTP UDP destination port value. If tftpdstp isn't
2722 defined, the normal port 69 is used.
2724 The purpose for tftpsrcp is to allow a TFTP server to
2725 blindly start the TFTP transfer using the pre-configured
2726 target IP address and UDP port. This has the effect of
2727 "punching through" the (Windows XP) firewall, allowing
2728 the remainder of the TFTP transfer to proceed normally.
2729 A better solution is to properly configure the firewall,
2730 but sometimes that is not allowed.
2735 This enables a generic 'hash' command which can produce
2736 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2740 Enable the hash verify command (hash -v). This adds to code
2743 Note: There is also a sha1sum command, which should perhaps
2744 be deprecated in favour of 'hash sha1'.
2746 - Freescale i.MX specific commands:
2747 CONFIG_CMD_HDMIDETECT
2748 This enables 'hdmidet' command which returns true if an
2749 HDMI monitor is detected. This command is i.MX 6 specific.
2751 - bootcount support:
2752 CONFIG_BOOTCOUNT_LIMIT
2754 This enables the bootcounter support, see:
2755 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2758 enable special bootcounter support on at91sam9xe based boards.
2760 enable special bootcounter support on da850 based boards.
2761 CONFIG_BOOTCOUNT_RAM
2762 enable support for the bootcounter in RAM
2763 CONFIG_BOOTCOUNT_I2C
2764 enable support for the bootcounter on an i2c (like RTC) device.
2765 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2766 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2768 CONFIG_BOOTCOUNT_ALEN = address len
2770 - Show boot progress:
2771 CONFIG_SHOW_BOOT_PROGRESS
2773 Defining this option allows to add some board-
2774 specific code (calling a user-provided function
2775 "show_boot_progress(int)") that enables you to show
2776 the system's boot progress on some display (for
2777 example, some LED's) on your board. At the moment,
2778 the following checkpoints are implemented:
2781 Legacy uImage format:
2784 1 common/cmd_bootm.c before attempting to boot an image
2785 -1 common/cmd_bootm.c Image header has bad magic number
2786 2 common/cmd_bootm.c Image header has correct magic number
2787 -2 common/cmd_bootm.c Image header has bad checksum
2788 3 common/cmd_bootm.c Image header has correct checksum
2789 -3 common/cmd_bootm.c Image data has bad checksum
2790 4 common/cmd_bootm.c Image data has correct checksum
2791 -4 common/cmd_bootm.c Image is for unsupported architecture
2792 5 common/cmd_bootm.c Architecture check OK
2793 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2794 6 common/cmd_bootm.c Image Type check OK
2795 -6 common/cmd_bootm.c gunzip uncompression error
2796 -7 common/cmd_bootm.c Unimplemented compression type
2797 7 common/cmd_bootm.c Uncompression OK
2798 8 common/cmd_bootm.c No uncompress/copy overwrite error
2799 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2801 9 common/image.c Start initial ramdisk verification
2802 -10 common/image.c Ramdisk header has bad magic number
2803 -11 common/image.c Ramdisk header has bad checksum
2804 10 common/image.c Ramdisk header is OK
2805 -12 common/image.c Ramdisk data has bad checksum
2806 11 common/image.c Ramdisk data has correct checksum
2807 12 common/image.c Ramdisk verification complete, start loading
2808 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2809 13 common/image.c Start multifile image verification
2810 14 common/image.c No initial ramdisk, no multifile, continue.
2812 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2814 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2815 -31 post/post.c POST test failed, detected by post_output_backlog()
2816 -32 post/post.c POST test failed, detected by post_run_single()
2818 34 common/cmd_doc.c before loading a Image from a DOC device
2819 -35 common/cmd_doc.c Bad usage of "doc" command
2820 35 common/cmd_doc.c correct usage of "doc" command
2821 -36 common/cmd_doc.c No boot device
2822 36 common/cmd_doc.c correct boot device
2823 -37 common/cmd_doc.c Unknown Chip ID on boot device
2824 37 common/cmd_doc.c correct chip ID found, device available
2825 -38 common/cmd_doc.c Read Error on boot device
2826 38 common/cmd_doc.c reading Image header from DOC device OK
2827 -39 common/cmd_doc.c Image header has bad magic number
2828 39 common/cmd_doc.c Image header has correct magic number
2829 -40 common/cmd_doc.c Error reading Image from DOC device
2830 40 common/cmd_doc.c Image header has correct magic number
2831 41 common/cmd_ide.c before loading a Image from a IDE device
2832 -42 common/cmd_ide.c Bad usage of "ide" command
2833 42 common/cmd_ide.c correct usage of "ide" command
2834 -43 common/cmd_ide.c No boot device
2835 43 common/cmd_ide.c boot device found
2836 -44 common/cmd_ide.c Device not available
2837 44 common/cmd_ide.c Device available
2838 -45 common/cmd_ide.c wrong partition selected
2839 45 common/cmd_ide.c partition selected
2840 -46 common/cmd_ide.c Unknown partition table
2841 46 common/cmd_ide.c valid partition table found
2842 -47 common/cmd_ide.c Invalid partition type
2843 47 common/cmd_ide.c correct partition type
2844 -48 common/cmd_ide.c Error reading Image Header on boot device
2845 48 common/cmd_ide.c reading Image Header from IDE device OK
2846 -49 common/cmd_ide.c Image header has bad magic number
2847 49 common/cmd_ide.c Image header has correct magic number
2848 -50 common/cmd_ide.c Image header has bad checksum
2849 50 common/cmd_ide.c Image header has correct checksum
2850 -51 common/cmd_ide.c Error reading Image from IDE device
2851 51 common/cmd_ide.c reading Image from IDE device OK
2852 52 common/cmd_nand.c before loading a Image from a NAND device
2853 -53 common/cmd_nand.c Bad usage of "nand" command
2854 53 common/cmd_nand.c correct usage of "nand" command
2855 -54 common/cmd_nand.c No boot device
2856 54 common/cmd_nand.c boot device found
2857 -55 common/cmd_nand.c Unknown Chip ID on boot device
2858 55 common/cmd_nand.c correct chip ID found, device available
2859 -56 common/cmd_nand.c Error reading Image Header on boot device
2860 56 common/cmd_nand.c reading Image Header from NAND device OK
2861 -57 common/cmd_nand.c Image header has bad magic number
2862 57 common/cmd_nand.c Image header has correct magic number
2863 -58 common/cmd_nand.c Error reading Image from NAND device
2864 58 common/cmd_nand.c reading Image from NAND device OK
2866 -60 common/env_common.c Environment has a bad CRC, using default
2868 64 net/eth.c starting with Ethernet configuration.
2869 -64 net/eth.c no Ethernet found.
2870 65 net/eth.c Ethernet found.
2872 -80 common/cmd_net.c usage wrong
2873 80 common/cmd_net.c before calling net_loop()
2874 -81 common/cmd_net.c some error in net_loop() occurred
2875 81 common/cmd_net.c net_loop() back without error
2876 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2877 82 common/cmd_net.c trying automatic boot
2878 83 common/cmd_net.c running "source" command
2879 -83 common/cmd_net.c some error in automatic boot or "source" command
2880 84 common/cmd_net.c end without errors
2885 100 common/cmd_bootm.c Kernel FIT Image has correct format
2886 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2887 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2888 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2889 102 common/cmd_bootm.c Kernel unit name specified
2890 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2891 103 common/cmd_bootm.c Found configuration node
2892 104 common/cmd_bootm.c Got kernel subimage node offset
2893 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2894 105 common/cmd_bootm.c Kernel subimage hash verification OK
2895 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2896 106 common/cmd_bootm.c Architecture check OK
2897 -106 common/cmd_bootm.c Kernel subimage has wrong type
2898 107 common/cmd_bootm.c Kernel subimage type OK
2899 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2900 108 common/cmd_bootm.c Got kernel subimage data/size
2901 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2902 -109 common/cmd_bootm.c Can't get kernel subimage type
2903 -110 common/cmd_bootm.c Can't get kernel subimage comp
2904 -111 common/cmd_bootm.c Can't get kernel subimage os
2905 -112 common/cmd_bootm.c Can't get kernel subimage load address
2906 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2908 120 common/image.c Start initial ramdisk verification
2909 -120 common/image.c Ramdisk FIT image has incorrect format
2910 121 common/image.c Ramdisk FIT image has correct format
2911 122 common/image.c No ramdisk subimage unit name, using configuration
2912 -122 common/image.c Can't get configuration for ramdisk subimage
2913 123 common/image.c Ramdisk unit name specified
2914 -124 common/image.c Can't get ramdisk subimage node offset
2915 125 common/image.c Got ramdisk subimage node offset
2916 -125 common/image.c Ramdisk subimage hash verification failed
2917 126 common/image.c Ramdisk subimage hash verification OK
2918 -126 common/image.c Ramdisk subimage for unsupported architecture
2919 127 common/image.c Architecture check OK
2920 -127 common/image.c Can't get ramdisk subimage data/size
2921 128 common/image.c Got ramdisk subimage data/size
2922 129 common/image.c Can't get ramdisk load address
2923 -129 common/image.c Got ramdisk load address
2925 -130 common/cmd_doc.c Incorrect FIT image format
2926 131 common/cmd_doc.c FIT image format OK
2928 -140 common/cmd_ide.c Incorrect FIT image format
2929 141 common/cmd_ide.c FIT image format OK
2931 -150 common/cmd_nand.c Incorrect FIT image format
2932 151 common/cmd_nand.c FIT image format OK
2934 - legacy image format:
2935 CONFIG_IMAGE_FORMAT_LEGACY
2936 enables the legacy image format support in U-Boot.
2939 enabled if CONFIG_FIT_SIGNATURE is not defined.
2941 CONFIG_DISABLE_IMAGE_LEGACY
2942 disable the legacy image format
2944 This define is introduced, as the legacy image format is
2945 enabled per default for backward compatibility.
2947 - Standalone program support:
2948 CONFIG_STANDALONE_LOAD_ADDR
2950 This option defines a board specific value for the
2951 address where standalone program gets loaded, thus
2952 overwriting the architecture dependent default
2955 - Frame Buffer Address:
2958 Define CONFIG_FB_ADDR if you want to use specific
2959 address for frame buffer. This is typically the case
2960 when using a graphics controller has separate video
2961 memory. U-Boot will then place the frame buffer at
2962 the given address instead of dynamically reserving it
2963 in system RAM by calling lcd_setmem(), which grabs
2964 the memory for the frame buffer depending on the
2965 configured panel size.
2967 Please see board_init_f function.
2969 - Automatic software updates via TFTP server
2971 CONFIG_UPDATE_TFTP_CNT_MAX
2972 CONFIG_UPDATE_TFTP_MSEC_MAX
2974 These options enable and control the auto-update feature;
2975 for a more detailed description refer to doc/README.update.
2977 - MTD Support (mtdparts command, UBI support)
2980 Adds the MTD device infrastructure from the Linux kernel.
2981 Needed for mtdparts command support.
2983 CONFIG_MTD_PARTITIONS
2985 Adds the MTD partitioning infrastructure from the Linux
2986 kernel. Needed for UBI support.
2991 Adds commands for interacting with MTD partitions formatted
2992 with the UBI flash translation layer
2994 Requires also defining CONFIG_RBTREE
2996 CONFIG_UBI_SILENCE_MSG
2998 Make the verbose messages from UBI stop printing. This leaves
2999 warnings and errors enabled.
3002 CONFIG_MTD_UBI_WL_THRESHOLD
3003 This parameter defines the maximum difference between the highest
3004 erase counter value and the lowest erase counter value of eraseblocks
3005 of UBI devices. When this threshold is exceeded, UBI starts performing
3006 wear leveling by means of moving data from eraseblock with low erase
3007 counter to eraseblocks with high erase counter.
3009 The default value should be OK for SLC NAND flashes, NOR flashes and
3010 other flashes which have eraseblock life-cycle 100000 or more.
3011 However, in case of MLC NAND flashes which typically have eraseblock
3012 life-cycle less than 10000, the threshold should be lessened (e.g.,
3013 to 128 or 256, although it does not have to be power of 2).
3017 CONFIG_MTD_UBI_BEB_LIMIT
3018 This option specifies the maximum bad physical eraseblocks UBI
3019 expects on the MTD device (per 1024 eraseblocks). If the
3020 underlying flash does not admit of bad eraseblocks (e.g. NOR
3021 flash), this value is ignored.
3023 NAND datasheets often specify the minimum and maximum NVM
3024 (Number of Valid Blocks) for the flashes' endurance lifetime.
3025 The maximum expected bad eraseblocks per 1024 eraseblocks
3026 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3027 which gives 20 for most NANDs (MaxNVB is basically the total
3028 count of eraseblocks on the chip).
3030 To put it differently, if this value is 20, UBI will try to
3031 reserve about 1.9% of physical eraseblocks for bad blocks
3032 handling. And that will be 1.9% of eraseblocks on the entire
3033 NAND chip, not just the MTD partition UBI attaches. This means
3034 that if you have, say, a NAND flash chip admits maximum 40 bad
3035 eraseblocks, and it is split on two MTD partitions of the same
3036 size, UBI will reserve 40 eraseblocks when attaching a
3041 CONFIG_MTD_UBI_FASTMAP
3042 Fastmap is a mechanism which allows attaching an UBI device
3043 in nearly constant time. Instead of scanning the whole MTD device it
3044 only has to locate a checkpoint (called fastmap) on the device.
3045 The on-flash fastmap contains all information needed to attach
3046 the device. Using fastmap makes only sense on large devices where
3047 attaching by scanning takes long. UBI will not automatically install
3048 a fastmap on old images, but you can set the UBI parameter
3049 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3050 that fastmap-enabled images are still usable with UBI implementations
3051 without fastmap support. On typical flash devices the whole fastmap
3052 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3054 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3055 Set this parameter to enable fastmap automatically on images
3059 CONFIG_MTD_UBI_FM_DEBUG
3060 Enable UBI fastmap debug
3066 Adds commands for interacting with UBI volumes formatted as
3067 UBIFS. UBIFS is read-only in u-boot.
3069 Requires UBI support as well as CONFIG_LZO
3071 CONFIG_UBIFS_SILENCE_MSG
3073 Make the verbose messages from UBIFS stop printing. This leaves
3074 warnings and errors enabled.
3078 Enable building of SPL globally.
3081 LDSCRIPT for linking the SPL binary.
3083 CONFIG_SPL_MAX_FOOTPRINT
3084 Maximum size in memory allocated to the SPL, BSS included.
3085 When defined, the linker checks that the actual memory
3086 used by SPL from _start to __bss_end does not exceed it.
3087 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3088 must not be both defined at the same time.
3091 Maximum size of the SPL image (text, data, rodata, and
3092 linker lists sections), BSS excluded.
3093 When defined, the linker checks that the actual size does
3096 CONFIG_SPL_TEXT_BASE
3097 TEXT_BASE for linking the SPL binary.
3099 CONFIG_SPL_RELOC_TEXT_BASE
3100 Address to relocate to. If unspecified, this is equal to
3101 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3103 CONFIG_SPL_BSS_START_ADDR
3104 Link address for the BSS within the SPL binary.
3106 CONFIG_SPL_BSS_MAX_SIZE
3107 Maximum size in memory allocated to the SPL BSS.
3108 When defined, the linker checks that the actual memory used
3109 by SPL from __bss_start to __bss_end does not exceed it.
3110 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3111 must not be both defined at the same time.
3114 Adress of the start of the stack SPL will use
3116 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3117 When defined, SPL will panic() if the image it has
3118 loaded does not have a signature.
3119 Defining this is useful when code which loads images
3120 in SPL cannot guarantee that absolutely all read errors
3122 An example is the LPC32XX MLC NAND driver, which will
3123 consider that a completely unreadable NAND block is bad,
3124 and thus should be skipped silently.
3126 CONFIG_SPL_RELOC_STACK
3127 Adress of the start of the stack SPL will use after
3128 relocation. If unspecified, this is equal to
3131 CONFIG_SYS_SPL_MALLOC_START
3132 Starting address of the malloc pool used in SPL.
3133 When this option is set the full malloc is used in SPL and
3134 it is set up by spl_init() and before that, the simple malloc()
3135 can be used if CONFIG_SYS_MALLOC_F is defined.
3137 CONFIG_SYS_SPL_MALLOC_SIZE
3138 The size of the malloc pool used in SPL.
3140 CONFIG_SPL_FRAMEWORK
3141 Enable the SPL framework under common/. This framework
3142 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3143 NAND loading of the Linux Kernel.
3146 Enable booting directly to an OS from SPL.
3147 See also: doc/README.falcon
3149 CONFIG_SPL_DISPLAY_PRINT
3150 For ARM, enable an optional function to print more information
3151 about the running system.
3153 CONFIG_SPL_INIT_MINIMAL
3154 Arch init code should be built for a very small image
3156 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3157 Partition on the MMC to load U-Boot from when the MMC is being
3160 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3161 Sector to load kernel uImage from when MMC is being
3162 used in raw mode (for Falcon mode)
3164 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3165 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3166 Sector and number of sectors to load kernel argument
3167 parameters from when MMC is being used in raw mode
3170 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3171 Partition on the MMC to load U-Boot from when the MMC is being
3174 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3175 Filename to read to load U-Boot when reading from filesystem
3177 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3178 Filename to read to load kernel uImage when reading
3179 from filesystem (for Falcon mode)
3181 CONFIG_SPL_FS_LOAD_ARGS_NAME
3182 Filename to read to load kernel argument parameters
3183 when reading from filesystem (for Falcon mode)
3185 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3186 Set this for NAND SPL on PPC mpc83xx targets, so that
3187 start.S waits for the rest of the SPL to load before
3188 continuing (the hardware starts execution after just
3189 loading the first page rather than the full 4K).
3191 CONFIG_SPL_SKIP_RELOCATE
3192 Avoid SPL relocation
3194 CONFIG_SPL_NAND_BASE
3195 Include nand_base.c in the SPL. Requires
3196 CONFIG_SPL_NAND_DRIVERS.
3198 CONFIG_SPL_NAND_DRIVERS
3199 SPL uses normal NAND drivers, not minimal drivers.
3202 Include standard software ECC in the SPL
3204 CONFIG_SPL_NAND_SIMPLE
3205 Support for NAND boot using simple NAND drivers that
3206 expose the cmd_ctrl() interface.
3209 Support for a lightweight UBI (fastmap) scanner and
3212 CONFIG_SPL_NAND_RAW_ONLY
3213 Support to boot only raw u-boot.bin images. Use this only
3214 if you need to save space.
3216 CONFIG_SPL_COMMON_INIT_DDR
3217 Set for common ddr init with serial presence detect in
3220 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3221 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3222 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3223 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3224 CONFIG_SYS_NAND_ECCBYTES
3225 Defines the size and behavior of the NAND that SPL uses
3228 CONFIG_SPL_NAND_BOOT
3229 Add support NAND boot
3231 CONFIG_SYS_NAND_U_BOOT_OFFS
3232 Location in NAND to read U-Boot from
3234 CONFIG_SYS_NAND_U_BOOT_DST
3235 Location in memory to load U-Boot to
3237 CONFIG_SYS_NAND_U_BOOT_SIZE
3238 Size of image to load
3240 CONFIG_SYS_NAND_U_BOOT_START
3241 Entry point in loaded image to jump to
3243 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3244 Define this if you need to first read the OOB and then the
3245 data. This is used, for example, on davinci platforms.
3247 CONFIG_SPL_OMAP3_ID_NAND
3248 Support for an OMAP3-specific set of functions to return the
3249 ID and MFR of the first attached NAND chip, if present.
3251 CONFIG_SPL_RAM_DEVICE
3252 Support for running image already present in ram, in SPL binary
3255 Image offset to which the SPL should be padded before appending
3256 the SPL payload. By default, this is defined as
3257 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3258 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3259 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3262 Final target image containing SPL and payload. Some SPLs
3263 use an arch-specific makefile fragment instead, for
3264 example if more than one image needs to be produced.
3266 CONFIG_FIT_SPL_PRINT
3267 Printing information about a FIT image adds quite a bit of
3268 code to SPL. So this is normally disabled in SPL. Use this
3269 option to re-enable it. This will affect the output of the
3270 bootm command when booting a FIT image.
3274 Enable building of TPL globally.
3277 Image offset to which the TPL should be padded before appending
3278 the TPL payload. By default, this is defined as
3279 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3280 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3281 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3283 - Interrupt support (PPC):
3285 There are common interrupt_init() and timer_interrupt()
3286 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3287 for CPU specific initialization. interrupt_init_cpu()
3288 should set decrementer_count to appropriate value. If
3289 CPU resets decrementer automatically after interrupt
3290 (ppc4xx) it should set decrementer_count to zero.
3291 timer_interrupt() calls timer_interrupt_cpu() for CPU
3292 specific handling. If board has watchdog / status_led
3293 / other_activity_monitor it works automatically from
3294 general timer_interrupt().
3297 Board initialization settings:
3298 ------------------------------
3300 During Initialization u-boot calls a number of board specific functions
3301 to allow the preparation of board specific prerequisites, e.g. pin setup
3302 before drivers are initialized. To enable these callbacks the
3303 following configuration macros have to be defined. Currently this is
3304 architecture specific, so please check arch/your_architecture/lib/board.c
3305 typically in board_init_f() and board_init_r().
3307 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3308 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3309 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3310 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3312 Configuration Settings:
3313 -----------------------
3315 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3316 Optionally it can be defined to support 64-bit memory commands.
3318 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3319 undefine this when you're short of memory.
3321 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3322 width of the commands listed in the 'help' command output.
3324 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3325 prompt for user input.
3327 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3329 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3331 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3333 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3334 the application (usually a Linux kernel) when it is
3337 - CONFIG_SYS_BAUDRATE_TABLE:
3338 List of legal baudrate settings for this board.
3340 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3341 Begin and End addresses of the area used by the
3344 - CONFIG_SYS_ALT_MEMTEST:
3345 Enable an alternate, more extensive memory test.
3347 - CONFIG_SYS_MEMTEST_SCRATCH:
3348 Scratch address used by the alternate memory test
3349 You only need to set this if address zero isn't writeable
3351 - CONFIG_SYS_MEM_RESERVE_SECURE
3352 Only implemented for ARMv8 for now.
3353 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3354 is substracted from total RAM and won't be reported to OS.
3355 This memory can be used as secure memory. A variable
3356 gd->arch.secure_ram is used to track the location. In systems
3357 the RAM base is not zero, or RAM is divided into banks,
3358 this variable needs to be recalcuated to get the address.
3360 - CONFIG_SYS_MEM_TOP_HIDE:
3361 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3362 this specified memory area will get subtracted from the top
3363 (end) of RAM and won't get "touched" at all by U-Boot. By
3364 fixing up gd->ram_size the Linux kernel should gets passed
3365 the now "corrected" memory size and won't touch it either.
3366 This should work for arch/ppc and arch/powerpc. Only Linux
3367 board ports in arch/powerpc with bootwrapper support that
3368 recalculate the memory size from the SDRAM controller setup
3369 will have to get fixed in Linux additionally.
3371 This option can be used as a workaround for the 440EPx/GRx
3372 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3375 WARNING: Please make sure that this value is a multiple of
3376 the Linux page size (normally 4k). If this is not the case,
3377 then the end address of the Linux memory will be located at a
3378 non page size aligned address and this could cause major
3381 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3382 Enable temporary baudrate change while serial download
3384 - CONFIG_SYS_SDRAM_BASE:
3385 Physical start address of SDRAM. _Must_ be 0 here.
3387 - CONFIG_SYS_FLASH_BASE:
3388 Physical start address of Flash memory.
3390 - CONFIG_SYS_MONITOR_BASE:
3391 Physical start address of boot monitor code (set by
3392 make config files to be same as the text base address
3393 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3394 CONFIG_SYS_FLASH_BASE when booting from flash.
3396 - CONFIG_SYS_MONITOR_LEN:
3397 Size of memory reserved for monitor code, used to
3398 determine _at_compile_time_ (!) if the environment is
3399 embedded within the U-Boot image, or in a separate
3402 - CONFIG_SYS_MALLOC_LEN:
3403 Size of DRAM reserved for malloc() use.
3405 - CONFIG_SYS_MALLOC_F_LEN
3406 Size of the malloc() pool for use before relocation. If
3407 this is defined, then a very simple malloc() implementation
3408 will become available before relocation. The address is just
3409 below the global data, and the stack is moved down to make
3412 This feature allocates regions with increasing addresses
3413 within the region. calloc() is supported, but realloc()
3414 is not available. free() is supported but does nothing.
3415 The memory will be freed (or in fact just forgotten) when
3416 U-Boot relocates itself.
3418 - CONFIG_SYS_MALLOC_SIMPLE
3419 Provides a simple and small malloc() and calloc() for those
3420 boards which do not use the full malloc in SPL (which is
3421 enabled with CONFIG_SYS_SPL_MALLOC_START).
3423 - CONFIG_SYS_NONCACHED_MEMORY:
3424 Size of non-cached memory area. This area of memory will be
3425 typically located right below the malloc() area and mapped
3426 uncached in the MMU. This is useful for drivers that would
3427 otherwise require a lot of explicit cache maintenance. For
3428 some drivers it's also impossible to properly maintain the
3429 cache. For example if the regions that need to be flushed
3430 are not a multiple of the cache-line size, *and* padding
3431 cannot be allocated between the regions to align them (i.e.
3432 if the HW requires a contiguous array of regions, and the
3433 size of each region is not cache-aligned), then a flush of
3434 one region may result in overwriting data that hardware has
3435 written to another region in the same cache-line. This can
3436 happen for example in network drivers where descriptors for
3437 buffers are typically smaller than the CPU cache-line (e.g.
3438 16 bytes vs. 32 or 64 bytes).
3440 Non-cached memory is only supported on 32-bit ARM at present.
3442 - CONFIG_SYS_BOOTM_LEN:
3443 Normally compressed uImages are limited to an
3444 uncompressed size of 8 MBytes. If this is not enough,
3445 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3446 to adjust this setting to your needs.
3448 - CONFIG_SYS_BOOTMAPSZ:
3449 Maximum size of memory mapped by the startup code of
3450 the Linux kernel; all data that must be processed by
3451 the Linux kernel (bd_info, boot arguments, FDT blob if
3452 used) must be put below this limit, unless "bootm_low"
3453 environment variable is defined and non-zero. In such case
3454 all data for the Linux kernel must be between "bootm_low"
3455 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3456 variable "bootm_mapsize" will override the value of
3457 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3458 then the value in "bootm_size" will be used instead.
3460 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3461 Enable initrd_high functionality. If defined then the
3462 initrd_high feature is enabled and the bootm ramdisk subcommand
3465 - CONFIG_SYS_BOOT_GET_CMDLINE:
3466 Enables allocating and saving kernel cmdline in space between
3467 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3469 - CONFIG_SYS_BOOT_GET_KBD:
3470 Enables allocating and saving a kernel copy of the bd_info in
3471 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3473 - CONFIG_SYS_MAX_FLASH_BANKS:
3474 Max number of Flash memory banks
3476 - CONFIG_SYS_MAX_FLASH_SECT:
3477 Max number of sectors on a Flash chip
3479 - CONFIG_SYS_FLASH_ERASE_TOUT:
3480 Timeout for Flash erase operations (in ms)
3482 - CONFIG_SYS_FLASH_WRITE_TOUT:
3483 Timeout for Flash write operations (in ms)
3485 - CONFIG_SYS_FLASH_LOCK_TOUT
3486 Timeout for Flash set sector lock bit operation (in ms)
3488 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3489 Timeout for Flash clear lock bits operation (in ms)
3491 - CONFIG_SYS_FLASH_PROTECTION
3492 If defined, hardware flash sectors protection is used
3493 instead of U-Boot software protection.
3495 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3497 Enable TFTP transfers directly to flash memory;
3498 without this option such a download has to be
3499 performed in two steps: (1) download to RAM, and (2)
3500 copy from RAM to flash.
3502 The two-step approach is usually more reliable, since
3503 you can check if the download worked before you erase
3504 the flash, but in some situations (when system RAM is
3505 too limited to allow for a temporary copy of the
3506 downloaded image) this option may be very useful.
3508 - CONFIG_SYS_FLASH_CFI:
3509 Define if the flash driver uses extra elements in the
3510 common flash structure for storing flash geometry.
3512 - CONFIG_FLASH_CFI_DRIVER
3513 This option also enables the building of the cfi_flash driver
3514 in the drivers directory
3516 - CONFIG_FLASH_CFI_MTD
3517 This option enables the building of the cfi_mtd driver
3518 in the drivers directory. The driver exports CFI flash
3521 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3522 Use buffered writes to flash.
3524 - CONFIG_FLASH_SPANSION_S29WS_N
3525 s29ws-n MirrorBit flash has non-standard addresses for buffered
3528 - CONFIG_SYS_FLASH_QUIET_TEST
3529 If this option is defined, the common CFI flash doesn't
3530 print it's warning upon not recognized FLASH banks. This
3531 is useful, if some of the configured banks are only
3532 optionally available.
3534 - CONFIG_FLASH_SHOW_PROGRESS
3535 If defined (must be an integer), print out countdown
3536 digits and dots. Recommended value: 45 (9..1) for 80
3537 column displays, 15 (3..1) for 40 column displays.
3539 - CONFIG_FLASH_VERIFY
3540 If defined, the content of the flash (destination) is compared
3541 against the source after the write operation. An error message
3542 will be printed when the contents are not identical.
3543 Please note that this option is useless in nearly all cases,
3544 since such flash programming errors usually are detected earlier
3545 while unprotecting/erasing/programming. Please only enable
3546 this option if you really know what you are doing.
3548 - CONFIG_SYS_RX_ETH_BUFFER:
3549 Defines the number of Ethernet receive buffers. On some
3550 Ethernet controllers it is recommended to set this value
3551 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3552 buffers can be full shortly after enabling the interface
3553 on high Ethernet traffic.
3554 Defaults to 4 if not defined.
3556 - CONFIG_ENV_MAX_ENTRIES
3558 Maximum number of entries in the hash table that is used
3559 internally to store the environment settings. The default
3560 setting is supposed to be generous and should work in most
3561 cases. This setting can be used to tune behaviour; see
3562 lib/hashtable.c for details.
3564 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3565 - CONFIG_ENV_FLAGS_LIST_STATIC
3566 Enable validation of the values given to environment variables when
3567 calling env set. Variables can be restricted to only decimal,
3568 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3569 the variables can also be restricted to IP address or MAC address.
3571 The format of the list is:
3572 type_attribute = [s|d|x|b|i|m]
3573 access_attribute = [a|r|o|c]
3574 attributes = type_attribute[access_attribute]
3575 entry = variable_name[:attributes]
3578 The type attributes are:
3579 s - String (default)
3582 b - Boolean ([1yYtT|0nNfF])
3586 The access attributes are:
3592 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3593 Define this to a list (string) to define the ".flags"
3594 environment variable in the default or embedded environment.
3596 - CONFIG_ENV_FLAGS_LIST_STATIC
3597 Define this to a list (string) to define validation that
3598 should be done if an entry is not found in the ".flags"
3599 environment variable. To override a setting in the static
3600 list, simply add an entry for the same variable name to the
3603 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3604 regular expression. This allows multiple variables to define the same
3605 flags without explicitly listing them for each variable.
3607 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3608 If defined, don't allow the -f switch to env set override variable
3612 If stdint.h is available with your toolchain you can define this
3613 option to enable it. You can provide option 'USE_STDINT=1' when
3614 building U-Boot to enable this.
3616 The following definitions that deal with the placement and management
3617 of environment data (variable area); in general, we support the
3618 following configurations:
3620 - CONFIG_BUILD_ENVCRC:
3622 Builds up envcrc with the target environment so that external utils
3623 may easily extract it and embed it in final U-Boot images.
3625 - CONFIG_ENV_IS_IN_FLASH:
3627 Define this if the environment is in flash memory.
3629 a) The environment occupies one whole flash sector, which is
3630 "embedded" in the text segment with the U-Boot code. This
3631 happens usually with "bottom boot sector" or "top boot
3632 sector" type flash chips, which have several smaller
3633 sectors at the start or the end. For instance, such a
3634 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3635 such a case you would place the environment in one of the
3636 4 kB sectors - with U-Boot code before and after it. With
3637 "top boot sector" type flash chips, you would put the
3638 environment in one of the last sectors, leaving a gap
3639 between U-Boot and the environment.
3641 - CONFIG_ENV_OFFSET:
3643 Offset of environment data (variable area) to the
3644 beginning of flash memory; for instance, with bottom boot
3645 type flash chips the second sector can be used: the offset
3646 for this sector is given here.
3648 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3652 This is just another way to specify the start address of
3653 the flash sector containing the environment (instead of
3656 - CONFIG_ENV_SECT_SIZE:
3658 Size of the sector containing the environment.
3661 b) Sometimes flash chips have few, equal sized, BIG sectors.
3662 In such a case you don't want to spend a whole sector for
3667 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3668 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3669 of this flash sector for the environment. This saves
3670 memory for the RAM copy of the environment.
3672 It may also save flash memory if you decide to use this
3673 when your environment is "embedded" within U-Boot code,
3674 since then the remainder of the flash sector could be used
3675 for U-Boot code. It should be pointed out that this is
3676 STRONGLY DISCOURAGED from a robustness point of view:
3677 updating the environment in flash makes it always
3678 necessary to erase the WHOLE sector. If something goes
3679 wrong before the contents has been restored from a copy in
3680 RAM, your target system will be dead.
3682 - CONFIG_ENV_ADDR_REDUND
3683 CONFIG_ENV_SIZE_REDUND
3685 These settings describe a second storage area used to hold
3686 a redundant copy of the environment data, so that there is
3687 a valid backup copy in case there is a power failure during
3688 a "saveenv" operation.
3690 BE CAREFUL! Any changes to the flash layout, and some changes to the
3691 source code will make it necessary to adapt <board>/u-boot.lds*
3695 - CONFIG_ENV_IS_IN_NVRAM:
3697 Define this if you have some non-volatile memory device
3698 (NVRAM, battery buffered SRAM) which you want to use for the
3704 These two #defines are used to determine the memory area you
3705 want to use for environment. It is assumed that this memory
3706 can just be read and written to, without any special
3709 BE CAREFUL! The first access to the environment happens quite early
3710 in U-Boot initialization (when we try to get the setting of for the
3711 console baudrate). You *MUST* have mapped your NVRAM area then, or
3714 Please note that even with NVRAM we still use a copy of the
3715 environment in RAM: we could work on NVRAM directly, but we want to
3716 keep settings there always unmodified except somebody uses "saveenv"
3717 to save the current settings.
3720 - CONFIG_ENV_IS_IN_EEPROM:
3722 Use this if you have an EEPROM or similar serial access
3723 device and a driver for it.
3725 - CONFIG_ENV_OFFSET:
3728 These two #defines specify the offset and size of the
3729 environment area within the total memory of your EEPROM.
3731 - CONFIG_SYS_I2C_EEPROM_ADDR:
3732 If defined, specified the chip address of the EEPROM device.
3733 The default address is zero.
3735 - CONFIG_SYS_I2C_EEPROM_BUS:
3736 If defined, specified the i2c bus of the EEPROM device.
3738 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3739 If defined, the number of bits used to address bytes in a
3740 single page in the EEPROM device. A 64 byte page, for example
3741 would require six bits.
3743 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3744 If defined, the number of milliseconds to delay between
3745 page writes. The default is zero milliseconds.
3747 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3748 The length in bytes of the EEPROM memory array address. Note
3749 that this is NOT the chip address length!
3751 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3752 EEPROM chips that implement "address overflow" are ones
3753 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3754 address and the extra bits end up in the "chip address" bit
3755 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3758 Note that we consider the length of the address field to
3759 still be one byte because the extra address bits are hidden
3760 in the chip address.
3762 - CONFIG_SYS_EEPROM_SIZE:
3763 The size in bytes of the EEPROM device.
3765 - CONFIG_ENV_EEPROM_IS_ON_I2C
3766 define this, if you have I2C and SPI activated, and your
3767 EEPROM, which holds the environment, is on the I2C bus.
3769 - CONFIG_I2C_ENV_EEPROM_BUS
3770 if you have an Environment on an EEPROM reached over
3771 I2C muxes, you can define here, how to reach this
3772 EEPROM. For example:
3774 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3776 EEPROM which holds the environment, is reached over
3777 a pca9547 i2c mux with address 0x70, channel 3.
3779 - CONFIG_ENV_IS_IN_DATAFLASH:
3781 Define this if you have a DataFlash memory device which you
3782 want to use for the environment.
3784 - CONFIG_ENV_OFFSET:
3788 These three #defines specify the offset and size of the
3789 environment area within the total memory of your DataFlash placed
3790 at the specified address.
3792 - CONFIG_ENV_IS_IN_SPI_FLASH:
3794 Define this if you have a SPI Flash memory device which you
3795 want to use for the environment.
3797 - CONFIG_ENV_OFFSET:
3800 These two #defines specify the offset and size of the
3801 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3802 aligned to an erase sector boundary.
3804 - CONFIG_ENV_SECT_SIZE:
3806 Define the SPI flash's sector size.
3808 - CONFIG_ENV_OFFSET_REDUND (optional):
3810 This setting describes a second storage area of CONFIG_ENV_SIZE
3811 size used to hold a redundant copy of the environment data, so
3812 that there is a valid backup copy in case there is a power failure
3813 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3814 aligned to an erase sector boundary.
3816 - CONFIG_ENV_SPI_BUS (optional):
3817 - CONFIG_ENV_SPI_CS (optional):
3819 Define the SPI bus and chip select. If not defined they will be 0.
3821 - CONFIG_ENV_SPI_MAX_HZ (optional):
3823 Define the SPI max work clock. If not defined then use 1MHz.
3825 - CONFIG_ENV_SPI_MODE (optional):
3827 Define the SPI work mode. If not defined then use SPI_MODE_3.
3829 - CONFIG_ENV_IS_IN_REMOTE:
3831 Define this if you have a remote memory space which you
3832 want to use for the local device's environment.
3837 These two #defines specify the address and size of the
3838 environment area within the remote memory space. The
3839 local device can get the environment from remote memory
3840 space by SRIO or PCIE links.
3842 BE CAREFUL! For some special cases, the local device can not use
3843 "saveenv" command. For example, the local device will get the
3844 environment stored in a remote NOR flash by SRIO or PCIE link,
3845 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3847 - CONFIG_ENV_IS_IN_NAND:
3849 Define this if you have a NAND device which you want to use
3850 for the environment.
3852 - CONFIG_ENV_OFFSET:
3855 These two #defines specify the offset and size of the environment
3856 area within the first NAND device. CONFIG_ENV_OFFSET must be
3857 aligned to an erase block boundary.
3859 - CONFIG_ENV_OFFSET_REDUND (optional):
3861 This setting describes a second storage area of CONFIG_ENV_SIZE
3862 size used to hold a redundant copy of the environment data, so
3863 that there is a valid backup copy in case there is a power failure
3864 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3865 aligned to an erase block boundary.
3867 - CONFIG_ENV_RANGE (optional):
3869 Specifies the length of the region in which the environment
3870 can be written. This should be a multiple of the NAND device's
3871 block size. Specifying a range with more erase blocks than
3872 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3873 the range to be avoided.
3875 - CONFIG_ENV_OFFSET_OOB (optional):
3877 Enables support for dynamically retrieving the offset of the
3878 environment from block zero's out-of-band data. The
3879 "nand env.oob" command can be used to record this offset.
3880 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3881 using CONFIG_ENV_OFFSET_OOB.
3883 - CONFIG_NAND_ENV_DST
3885 Defines address in RAM to which the nand_spl code should copy the
3886 environment. If redundant environment is used, it will be copied to
3887 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3889 - CONFIG_ENV_IS_IN_UBI:
3891 Define this if you have an UBI volume that you want to use for the
3892 environment. This has the benefit of wear-leveling the environment
3893 accesses, which is important on NAND.
3895 - CONFIG_ENV_UBI_PART:
3897 Define this to a string that is the mtd partition containing the UBI.
3899 - CONFIG_ENV_UBI_VOLUME:
3901 Define this to the name of the volume that you want to store the
3904 - CONFIG_ENV_UBI_VOLUME_REDUND:
3906 Define this to the name of another volume to store a second copy of
3907 the environment in. This will enable redundant environments in UBI.
3908 It is assumed that both volumes are in the same MTD partition.
3910 - CONFIG_UBI_SILENCE_MSG
3911 - CONFIG_UBIFS_SILENCE_MSG
3913 You will probably want to define these to avoid a really noisy system
3914 when storing the env in UBI.
3916 - CONFIG_ENV_IS_IN_FAT:
3917 Define this if you want to use the FAT file system for the environment.
3919 - FAT_ENV_INTERFACE:
3921 Define this to a string that is the name of the block device.
3923 - FAT_ENV_DEVICE_AND_PART:
3925 Define this to a string to specify the partition of the device. It can
3928 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3929 - "D:P": device D partition P. Error occurs if device D has no
3932 - "D" or "D:": device D partition 1 if device D has partition
3933 table, or the whole device D if has no partition
3935 - "D:auto": first partition in device D with bootable flag set.
3936 If none, first valid partition in device D. If no
3937 partition table then means device D.
3941 It's a string of the FAT file name. This file use to store the
3945 This should be defined. Otherwise it cannot save the environment file.
3947 - CONFIG_ENV_IS_IN_MMC:
3949 Define this if you have an MMC device which you want to use for the
3952 - CONFIG_SYS_MMC_ENV_DEV:
3954 Specifies which MMC device the environment is stored in.
3956 - CONFIG_SYS_MMC_ENV_PART (optional):
3958 Specifies which MMC partition the environment is stored in. If not
3959 set, defaults to partition 0, the user area. Common values might be
3960 1 (first MMC boot partition), 2 (second MMC boot partition).
3962 - CONFIG_ENV_OFFSET:
3965 These two #defines specify the offset and size of the environment
3966 area within the specified MMC device.
3968 If offset is positive (the usual case), it is treated as relative to
3969 the start of the MMC partition. If offset is negative, it is treated
3970 as relative to the end of the MMC partition. This can be useful if
3971 your board may be fitted with different MMC devices, which have
3972 different sizes for the MMC partitions, and you always want the
3973 environment placed at the very end of the partition, to leave the
3974 maximum possible space before it, to store other data.
3976 These two values are in units of bytes, but must be aligned to an
3977 MMC sector boundary.
3979 - CONFIG_ENV_OFFSET_REDUND (optional):
3981 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3982 hold a redundant copy of the environment data. This provides a
3983 valid backup copy in case the other copy is corrupted, e.g. due
3984 to a power failure during a "saveenv" operation.
3986 This value may also be positive or negative; this is handled in the
3987 same way as CONFIG_ENV_OFFSET.
3989 This value is also in units of bytes, but must also be aligned to
3990 an MMC sector boundary.
3992 - CONFIG_ENV_SIZE_REDUND (optional):
3994 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3995 set. If this value is set, it must be set to the same value as
3998 - CONFIG_SYS_SPI_INIT_OFFSET
4000 Defines offset to the initial SPI buffer area in DPRAM. The
4001 area is used at an early stage (ROM part) if the environment
4002 is configured to reside in the SPI EEPROM: We need a 520 byte
4003 scratch DPRAM area. It is used between the two initialization
4004 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4005 to be a good choice since it makes it far enough from the
4006 start of the data area as well as from the stack pointer.
4008 Please note that the environment is read-only until the monitor
4009 has been relocated to RAM and a RAM copy of the environment has been
4010 created; also, when using EEPROM you will have to use getenv_f()
4011 until then to read environment variables.
4013 The environment is protected by a CRC32 checksum. Before the monitor
4014 is relocated into RAM, as a result of a bad CRC you will be working
4015 with the compiled-in default environment - *silently*!!! [This is
4016 necessary, because the first environment variable we need is the
4017 "baudrate" setting for the console - if we have a bad CRC, we don't
4018 have any device yet where we could complain.]
4020 Note: once the monitor has been relocated, then it will complain if
4021 the default environment is used; a new CRC is computed as soon as you
4022 use the "saveenv" command to store a valid environment.
4024 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4025 Echo the inverted Ethernet link state to the fault LED.
4027 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4028 also needs to be defined.
4030 - CONFIG_SYS_FAULT_MII_ADDR:
4031 MII address of the PHY to check for the Ethernet link state.
4033 - CONFIG_NS16550_MIN_FUNCTIONS:
4034 Define this if you desire to only have use of the NS16550_init
4035 and NS16550_putc functions for the serial driver located at
4036 drivers/serial/ns16550.c. This option is useful for saving
4037 space for already greatly restricted images, including but not
4038 limited to NAND_SPL configurations.
4040 - CONFIG_DISPLAY_BOARDINFO
4041 Display information about the board that U-Boot is running on
4042 when U-Boot starts up. The board function checkboard() is called
4045 - CONFIG_DISPLAY_BOARDINFO_LATE
4046 Similar to the previous option, but display this information
4047 later, once stdio is running and output goes to the LCD, if
4050 - CONFIG_BOARD_SIZE_LIMIT:
4051 Maximum size of the U-Boot image. When defined, the
4052 build system checks that the actual size does not
4055 Low Level (hardware related) configuration options:
4056 ---------------------------------------------------
4058 - CONFIG_SYS_CACHELINE_SIZE:
4059 Cache Line Size of the CPU.
4061 - CONFIG_SYS_DEFAULT_IMMR:
4062 Default address of the IMMR after system reset.
4064 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4065 and RPXsuper) to be able to adjust the position of
4066 the IMMR register after a reset.
4068 - CONFIG_SYS_CCSRBAR_DEFAULT:
4069 Default (power-on reset) physical address of CCSR on Freescale
4072 - CONFIG_SYS_CCSRBAR:
4073 Virtual address of CCSR. On a 32-bit build, this is typically
4074 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4076 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4077 for cross-platform code that uses that macro instead.
4079 - CONFIG_SYS_CCSRBAR_PHYS:
4080 Physical address of CCSR. CCSR can be relocated to a new
4081 physical address, if desired. In this case, this macro should
4082 be set to that address. Otherwise, it should be set to the
4083 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4084 is typically relocated on 36-bit builds. It is recommended
4085 that this macro be defined via the _HIGH and _LOW macros:
4087 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4088 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4090 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4091 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4092 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4093 used in assembly code, so it must not contain typecasts or
4094 integer size suffixes (e.g. "ULL").
4096 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4097 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4098 used in assembly code, so it must not contain typecasts or
4099 integer size suffixes (e.g. "ULL").
4101 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4102 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4103 forced to a value that ensures that CCSR is not relocated.
4105 - Floppy Disk Support:
4106 CONFIG_SYS_FDC_DRIVE_NUMBER
4108 the default drive number (default value 0)
4110 CONFIG_SYS_ISA_IO_STRIDE
4112 defines the spacing between FDC chipset registers
4115 CONFIG_SYS_ISA_IO_OFFSET
4117 defines the offset of register from address. It
4118 depends on which part of the data bus is connected to
4119 the FDC chipset. (default value 0)
4121 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4122 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4125 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4126 fdc_hw_init() is called at the beginning of the FDC
4127 setup. fdc_hw_init() must be provided by the board
4128 source code. It is used to make hardware-dependent
4132 Most IDE controllers were designed to be connected with PCI
4133 interface. Only few of them were designed for AHB interface.
4134 When software is doing ATA command and data transfer to
4135 IDE devices through IDE-AHB controller, some additional
4136 registers accessing to these kind of IDE-AHB controller
4139 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4140 DO NOT CHANGE unless you know exactly what you're
4141 doing! (11-4) [MPC8xx/82xx systems only]
4143 - CONFIG_SYS_INIT_RAM_ADDR:
4145 Start address of memory area that can be used for
4146 initial data and stack; please note that this must be
4147 writable memory that is working WITHOUT special
4148 initialization, i. e. you CANNOT use normal RAM which
4149 will become available only after programming the
4150 memory controller and running certain initialization
4153 U-Boot uses the following memory types:
4154 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4155 - MPC824X: data cache
4156 - PPC4xx: data cache
4158 - CONFIG_SYS_GBL_DATA_OFFSET:
4160 Offset of the initial data structure in the memory
4161 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4162 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4163 data is located at the end of the available space
4164 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4165 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4166 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4167 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4170 On the MPC824X (or other systems that use the data
4171 cache for initial memory) the address chosen for
4172 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4173 point to an otherwise UNUSED address space between
4174 the top of RAM and the start of the PCI space.
4176 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4178 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4180 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4182 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4184 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4186 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4188 - CONFIG_SYS_OR_TIMING_SDRAM:
4191 - CONFIG_SYS_MAMR_PTA:
4192 periodic timer for refresh
4194 - CONFIG_SYS_DER: Debug Event Register (37-47)
4196 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4197 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4198 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4199 CONFIG_SYS_BR1_PRELIM:
4200 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4202 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4203 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4204 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4205 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4207 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4208 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4209 Machine Mode Register and Memory Periodic Timer
4210 Prescaler definitions (SDRAM timing)
4212 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4213 enable I2C microcode relocation patch (MPC8xx);
4214 define relocation offset in DPRAM [DSP2]
4216 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4217 enable SMC microcode relocation patch (MPC8xx);
4218 define relocation offset in DPRAM [SMC1]
4220 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4221 enable SPI microcode relocation patch (MPC8xx);
4222 define relocation offset in DPRAM [SCC4]
4224 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4225 Offset of the bootmode word in DPRAM used by post
4226 (Power On Self Tests). This definition overrides
4227 #define'd default value in commproc.h resp.
4230 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4231 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4232 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4233 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4234 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4235 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4236 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4237 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4238 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4240 - CONFIG_PCI_DISABLE_PCIE:
4241 Disable PCI-Express on systems where it is supported but not
4244 - CONFIG_PCI_ENUM_ONLY
4245 Only scan through and get the devices on the buses.
4246 Don't do any setup work, presumably because someone or
4247 something has already done it, and we don't need to do it
4248 a second time. Useful for platforms that are pre-booted
4249 by coreboot or similar.
4251 - CONFIG_PCI_INDIRECT_BRIDGE:
4252 Enable support for indirect PCI bridges.
4255 Chip has SRIO or not
4258 Board has SRIO 1 port available
4261 Board has SRIO 2 port available
4263 - CONFIG_SRIO_PCIE_BOOT_MASTER
4264 Board can support master function for Boot from SRIO and PCIE
4266 - CONFIG_SYS_SRIOn_MEM_VIRT:
4267 Virtual Address of SRIO port 'n' memory region
4269 - CONFIG_SYS_SRIOn_MEM_PHYS:
4270 Physical Address of SRIO port 'n' memory region
4272 - CONFIG_SYS_SRIOn_MEM_SIZE:
4273 Size of SRIO port 'n' memory region
4275 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4276 Defined to tell the NAND controller that the NAND chip is using
4278 Not all NAND drivers use this symbol.
4279 Example of drivers that use it:
4280 - drivers/mtd/nand/ndfc.c
4281 - drivers/mtd/nand/mxc_nand.c
4283 - CONFIG_SYS_NDFC_EBC0_CFG
4284 Sets the EBC0_CFG register for the NDFC. If not defined
4285 a default value will be used.
4288 Get DDR timing information from an I2C EEPROM. Common
4289 with pluggable memory modules such as SODIMMs
4292 I2C address of the SPD EEPROM
4294 - CONFIG_SYS_SPD_BUS_NUM
4295 If SPD EEPROM is on an I2C bus other than the first
4296 one, specify here. Note that the value must resolve
4297 to something your driver can deal with.
4299 - CONFIG_SYS_DDR_RAW_TIMING
4300 Get DDR timing information from other than SPD. Common with
4301 soldered DDR chips onboard without SPD. DDR raw timing
4302 parameters are extracted from datasheet and hard-coded into
4303 header files or board specific files.
4305 - CONFIG_FSL_DDR_INTERACTIVE
4306 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4308 - CONFIG_FSL_DDR_SYNC_REFRESH
4309 Enable sync of refresh for multiple controllers.
4311 - CONFIG_FSL_DDR_BIST
4312 Enable built-in memory test for Freescale DDR controllers.
4314 - CONFIG_SYS_83XX_DDR_USES_CS0
4315 Only for 83xx systems. If specified, then DDR should
4316 be configured using CS0 and CS1 instead of CS2 and CS3.
4318 - CONFIG_ETHER_ON_FEC[12]
4319 Define to enable FEC[12] on a 8xx series processor.
4321 - CONFIG_FEC[12]_PHY
4322 Define to the hardcoded PHY address which corresponds
4323 to the given FEC; i. e.
4324 #define CONFIG_FEC1_PHY 4
4325 means that the PHY with address 4 is connected to FEC1
4327 When set to -1, means to probe for first available.
4329 - CONFIG_FEC[12]_PHY_NORXERR
4330 The PHY does not have a RXERR line (RMII only).
4331 (so program the FEC to ignore it).
4334 Enable RMII mode for all FECs.
4335 Note that this is a global option, we can't
4336 have one FEC in standard MII mode and another in RMII mode.
4338 - CONFIG_CRC32_VERIFY
4339 Add a verify option to the crc32 command.
4342 => crc32 -v <address> <count> <crc32>
4344 Where address/count indicate a memory area
4345 and crc32 is the correct crc32 which the
4349 Add the "loopw" memory command. This only takes effect if
4350 the memory commands are activated globally (CONFIG_CMD_MEM).
4353 Add the "mdc" and "mwc" memory commands. These are cyclic
4358 This command will print 4 bytes (10,11,12,13) each 500 ms.
4360 => mwc.l 100 12345678 10
4361 This command will write 12345678 to address 100 all 10 ms.
4363 This only takes effect if the memory commands are activated
4364 globally (CONFIG_CMD_MEM).
4366 - CONFIG_SKIP_LOWLEVEL_INIT
4367 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4368 low level initializations (like setting up the memory
4369 controller) are omitted and/or U-Boot does not
4370 relocate itself into RAM.
4372 Normally this variable MUST NOT be defined. The only
4373 exception is when U-Boot is loaded (to RAM) by some
4374 other boot loader or by a debugger which performs
4375 these initializations itself.
4377 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4378 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4379 to be skipped. The normal CP15 init (such as enabling the
4380 instruction cache) is still performed.
4383 Modifies the behaviour of start.S when compiling a loader
4384 that is executed before the actual U-Boot. E.g. when
4385 compiling a NAND SPL.
4388 Modifies the behaviour of start.S when compiling a loader
4389 that is executed after the SPL and before the actual U-Boot.
4390 It is loaded by the SPL.
4392 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4393 Only for 85xx systems. If this variable is specified, the section
4394 .resetvec is not kept and the section .bootpg is placed in the
4395 previous 4k of the .text section.
4397 - CONFIG_ARCH_MAP_SYSMEM
4398 Generally U-Boot (and in particular the md command) uses
4399 effective address. It is therefore not necessary to regard
4400 U-Boot address as virtual addresses that need to be translated
4401 to physical addresses. However, sandbox requires this, since
4402 it maintains its own little RAM buffer which contains all
4403 addressable memory. This option causes some memory accesses
4404 to be mapped through map_sysmem() / unmap_sysmem().
4406 - CONFIG_X86_RESET_VECTOR
4407 If defined, the x86 reset vector code is included. This is not
4408 needed when U-Boot is running from Coreboot.
4410 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4411 Enables the RTC32K OSC on AM33xx based plattforms
4413 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4414 Option to disable subpage write in NAND driver
4415 driver that uses this:
4416 drivers/mtd/nand/davinci_nand.c
4418 Freescale QE/FMAN Firmware Support:
4419 -----------------------------------
4421 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4422 loading of "firmware", which is encoded in the QE firmware binary format.
4423 This firmware often needs to be loaded during U-Boot booting, so macros
4424 are used to identify the storage device (NOR flash, SPI, etc) and the address
4427 - CONFIG_SYS_FMAN_FW_ADDR
4428 The address in the storage device where the FMAN microcode is located. The
4429 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4432 - CONFIG_SYS_QE_FW_ADDR
4433 The address in the storage device where the QE microcode is located. The
4434 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4437 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4438 The maximum possible size of the firmware. The firmware binary format
4439 has a field that specifies the actual size of the firmware, but it
4440 might not be possible to read any part of the firmware unless some
4441 local storage is allocated to hold the entire firmware first.
4443 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4444 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4445 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4446 virtual address in NOR flash.
4448 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4449 Specifies that QE/FMAN firmware is located in NAND flash.
4450 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4452 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4453 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4454 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4456 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4457 Specifies that QE/FMAN firmware is located in the remote (master)
4458 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4459 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4460 window->master inbound window->master LAW->the ucode address in
4461 master's memory space.
4463 Freescale Layerscape Management Complex Firmware Support:
4464 ---------------------------------------------------------
4465 The Freescale Layerscape Management Complex (MC) supports the loading of
4467 This firmware often needs to be loaded during U-Boot booting, so macros
4468 are used to identify the storage device (NOR flash, SPI, etc) and the address
4471 - CONFIG_FSL_MC_ENET
4472 Enable the MC driver for Layerscape SoCs.
4474 Freescale Layerscape Debug Server Support:
4475 -------------------------------------------
4476 The Freescale Layerscape Debug Server Support supports the loading of
4477 "Debug Server firmware" and triggering SP boot-rom.
4478 This firmware often needs to be loaded during U-Boot booting.
4480 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4481 Define alignment of reserved memory MC requires
4486 In order to achieve reproducible builds, timestamps used in the U-Boot build
4487 process have to be set to a fixed value.
4489 This is done using the SOURCE_DATE_EPOCH environment variable.
4490 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4491 option for U-Boot or an environment variable in U-Boot.
4493 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4495 Building the Software:
4496 ======================
4498 Building U-Boot has been tested in several native build environments
4499 and in many different cross environments. Of course we cannot support
4500 all possibly existing versions of cross development tools in all
4501 (potentially obsolete) versions. In case of tool chain problems we
4502 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4503 which is extensively used to build and test U-Boot.
4505 If you are not using a native environment, it is assumed that you
4506 have GNU cross compiling tools available in your path. In this case,
4507 you must set the environment variable CROSS_COMPILE in your shell.
4508 Note that no changes to the Makefile or any other source files are
4509 necessary. For example using the ELDK on a 4xx CPU, please enter:
4511 $ CROSS_COMPILE=ppc_4xx-
4512 $ export CROSS_COMPILE
4514 Note: If you wish to generate Windows versions of the utilities in
4515 the tools directory you can use the MinGW toolchain
4516 (http://www.mingw.org). Set your HOST tools to the MinGW
4517 toolchain and execute 'make tools'. For example:
4519 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4521 Binaries such as tools/mkimage.exe will be created which can
4522 be executed on computers running Windows.
4524 U-Boot is intended to be simple to build. After installing the
4525 sources you must configure U-Boot for one specific board type. This
4530 where "NAME_defconfig" is the name of one of the existing configu-
4531 rations; see boards.cfg for supported names.
4533 Note: for some board special configuration names may exist; check if
4534 additional information is available from the board vendor; for
4535 instance, the TQM823L systems are available without (standard)
4536 or with LCD support. You can select such additional "features"
4537 when choosing the configuration, i. e.
4539 make TQM823L_defconfig
4540 - will configure for a plain TQM823L, i. e. no LCD support
4542 make TQM823L_LCD_defconfig
4543 - will configure for a TQM823L with U-Boot console on LCD
4548 Finally, type "make all", and you should get some working U-Boot
4549 images ready for download to / installation on your system:
4551 - "u-boot.bin" is a raw binary image
4552 - "u-boot" is an image in ELF binary format
4553 - "u-boot.srec" is in Motorola S-Record format
4555 By default the build is performed locally and the objects are saved
4556 in the source directory. One of the two methods can be used to change
4557 this behavior and build U-Boot to some external directory:
4559 1. Add O= to the make command line invocations:
4561 make O=/tmp/build distclean
4562 make O=/tmp/build NAME_defconfig
4563 make O=/tmp/build all
4565 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4567 export KBUILD_OUTPUT=/tmp/build
4572 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4576 Please be aware that the Makefiles assume you are using GNU make, so
4577 for instance on NetBSD you might need to use "gmake" instead of
4581 If the system board that you have is not listed, then you will need
4582 to port U-Boot to your hardware platform. To do this, follow these
4585 1. Create a new directory to hold your board specific code. Add any
4586 files you need. In your board directory, you will need at least
4587 the "Makefile" and a "<board>.c".
4588 2. Create a new configuration file "include/configs/<board>.h" for
4590 3. If you're porting U-Boot to a new CPU, then also create a new
4591 directory to hold your CPU specific code. Add any files you need.
4592 4. Run "make <board>_defconfig" with your new name.
4593 5. Type "make", and you should get a working "u-boot.srec" file
4594 to be installed on your target system.
4595 6. Debug and solve any problems that might arise.
4596 [Of course, this last step is much harder than it sounds.]
4599 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4600 ==============================================================
4602 If you have modified U-Boot sources (for instance added a new board
4603 or support for new devices, a new CPU, etc.) you are expected to
4604 provide feedback to the other developers. The feedback normally takes
4605 the form of a "patch", i. e. a context diff against a certain (latest
4606 official or latest in the git repository) version of U-Boot sources.
4608 But before you submit such a patch, please verify that your modifi-
4609 cation did not break existing code. At least make sure that *ALL* of
4610 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4611 just run the buildman script (tools/buildman/buildman), which will
4612 configure and build U-Boot for ALL supported system. Be warned, this
4613 will take a while. Please see the buildman README, or run 'buildman -H'
4617 See also "U-Boot Porting Guide" below.
4620 Monitor Commands - Overview:
4621 ============================
4623 go - start application at address 'addr'
4624 run - run commands in an environment variable
4625 bootm - boot application image from memory
4626 bootp - boot image via network using BootP/TFTP protocol
4627 bootz - boot zImage from memory
4628 tftpboot- boot image via network using TFTP protocol
4629 and env variables "ipaddr" and "serverip"
4630 (and eventually "gatewayip")
4631 tftpput - upload a file via network using TFTP protocol
4632 rarpboot- boot image via network using RARP/TFTP protocol
4633 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4634 loads - load S-Record file over serial line
4635 loadb - load binary file over serial line (kermit mode)
4637 mm - memory modify (auto-incrementing)
4638 nm - memory modify (constant address)
4639 mw - memory write (fill)
4641 cmp - memory compare
4642 crc32 - checksum calculation
4643 i2c - I2C sub-system
4644 sspi - SPI utility commands
4645 base - print or set address offset
4646 printenv- print environment variables
4647 setenv - set environment variables
4648 saveenv - save environment variables to persistent storage
4649 protect - enable or disable FLASH write protection
4650 erase - erase FLASH memory
4651 flinfo - print FLASH memory information
4652 nand - NAND memory operations (see doc/README.nand)
4653 bdinfo - print Board Info structure
4654 iminfo - print header information for application image
4655 coninfo - print console devices and informations
4656 ide - IDE sub-system
4657 loop - infinite loop on address range
4658 loopw - infinite write loop on address range
4659 mtest - simple RAM test
4660 icache - enable or disable instruction cache
4661 dcache - enable or disable data cache
4662 reset - Perform RESET of the CPU
4663 echo - echo args to console
4664 version - print monitor version
4665 help - print online help
4666 ? - alias for 'help'
4669 Monitor Commands - Detailed Description:
4670 ========================================
4674 For now: just type "help <command>".
4677 Environment Variables:
4678 ======================
4680 U-Boot supports user configuration using Environment Variables which
4681 can be made persistent by saving to Flash memory.
4683 Environment Variables are set using "setenv", printed using
4684 "printenv", and saved to Flash using "saveenv". Using "setenv"
4685 without a value can be used to delete a variable from the
4686 environment. As long as you don't save the environment you are
4687 working with an in-memory copy. In case the Flash area containing the
4688 environment is erased by accident, a default environment is provided.
4690 Some configuration options can be set using Environment Variables.
4692 List of environment variables (most likely not complete):
4694 baudrate - see CONFIG_BAUDRATE
4696 bootdelay - see CONFIG_BOOTDELAY
4698 bootcmd - see CONFIG_BOOTCOMMAND
4700 bootargs - Boot arguments when booting an RTOS image
4702 bootfile - Name of the image to load with TFTP
4704 bootm_low - Memory range available for image processing in the bootm
4705 command can be restricted. This variable is given as
4706 a hexadecimal number and defines lowest address allowed
4707 for use by the bootm command. See also "bootm_size"
4708 environment variable. Address defined by "bootm_low" is
4709 also the base of the initial memory mapping for the Linux
4710 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4713 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4714 This variable is given as a hexadecimal number and it
4715 defines the size of the memory region starting at base
4716 address bootm_low that is accessible by the Linux kernel
4717 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4718 as the default value if it is defined, and bootm_size is
4721 bootm_size - Memory range available for image processing in the bootm
4722 command can be restricted. This variable is given as
4723 a hexadecimal number and defines the size of the region
4724 allowed for use by the bootm command. See also "bootm_low"
4725 environment variable.
4727 updatefile - Location of the software update file on a TFTP server, used
4728 by the automatic software update feature. Please refer to
4729 documentation in doc/README.update for more details.
4731 autoload - if set to "no" (any string beginning with 'n'),
4732 "bootp" will just load perform a lookup of the
4733 configuration from the BOOTP server, but not try to
4734 load any image using TFTP
4736 autostart - if set to "yes", an image loaded using the "bootp",
4737 "rarpboot", "tftpboot" or "diskboot" commands will
4738 be automatically started (by internally calling
4741 If set to "no", a standalone image passed to the
4742 "bootm" command will be copied to the load address
4743 (and eventually uncompressed), but NOT be started.
4744 This can be used to load and uncompress arbitrary
4747 fdt_high - if set this restricts the maximum address that the
4748 flattened device tree will be copied into upon boot.
4749 For example, if you have a system with 1 GB memory
4750 at physical address 0x10000000, while Linux kernel
4751 only recognizes the first 704 MB as low memory, you
4752 may need to set fdt_high as 0x3C000000 to have the
4753 device tree blob be copied to the maximum address
4754 of the 704 MB low memory, so that Linux kernel can
4755 access it during the boot procedure.
4757 If this is set to the special value 0xFFFFFFFF then
4758 the fdt will not be copied at all on boot. For this
4759 to work it must reside in writable memory, have
4760 sufficient padding on the end of it for u-boot to
4761 add the information it needs into it, and the memory
4762 must be accessible by the kernel.
4764 fdtcontroladdr- if set this is the address of the control flattened
4765 device tree used by U-Boot when CONFIG_OF_CONTROL is
4768 i2cfast - (PPC405GP|PPC405EP only)
4769 if set to 'y' configures Linux I2C driver for fast
4770 mode (400kHZ). This environment variable is used in
4771 initialization code. So, for changes to be effective
4772 it must be saved and board must be reset.
4774 initrd_high - restrict positioning of initrd images:
4775 If this variable is not set, initrd images will be
4776 copied to the highest possible address in RAM; this
4777 is usually what you want since it allows for
4778 maximum initrd size. If for some reason you want to
4779 make sure that the initrd image is loaded below the
4780 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4781 variable to a value of "no" or "off" or "0".
4782 Alternatively, you can set it to a maximum upper
4783 address to use (U-Boot will still check that it
4784 does not overwrite the U-Boot stack and data).
4786 For instance, when you have a system with 16 MB
4787 RAM, and want to reserve 4 MB from use by Linux,
4788 you can do this by adding "mem=12M" to the value of
4789 the "bootargs" variable. However, now you must make
4790 sure that the initrd image is placed in the first
4791 12 MB as well - this can be done with
4793 setenv initrd_high 00c00000
4795 If you set initrd_high to 0xFFFFFFFF, this is an
4796 indication to U-Boot that all addresses are legal
4797 for the Linux kernel, including addresses in flash
4798 memory. In this case U-Boot will NOT COPY the
4799 ramdisk at all. This may be useful to reduce the
4800 boot time on your system, but requires that this
4801 feature is supported by your Linux kernel.
4803 ipaddr - IP address; needed for tftpboot command
4805 loadaddr - Default load address for commands like "bootp",
4806 "rarpboot", "tftpboot", "loadb" or "diskboot"
4808 loads_echo - see CONFIG_LOADS_ECHO
4810 serverip - TFTP server IP address; needed for tftpboot command
4812 bootretry - see CONFIG_BOOT_RETRY_TIME
4814 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4816 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4818 ethprime - controls which interface is used first.
4820 ethact - controls which interface is currently active.
4821 For example you can do the following
4823 => setenv ethact FEC
4824 => ping 192.168.0.1 # traffic sent on FEC
4825 => setenv ethact SCC
4826 => ping 10.0.0.1 # traffic sent on SCC
4828 ethrotate - When set to "no" U-Boot does not go through all
4829 available network interfaces.
4830 It just stays at the currently selected interface.
4832 netretry - When set to "no" each network operation will
4833 either succeed or fail without retrying.
4834 When set to "once" the network operation will
4835 fail when all the available network interfaces
4836 are tried once without success.
4837 Useful on scripts which control the retry operation
4840 npe_ucode - set load address for the NPE microcode
4842 silent_linux - If set then Linux will be told to boot silently, by
4843 changing the console to be empty. If "yes" it will be
4844 made silent. If "no" it will not be made silent. If
4845 unset, then it will be made silent if the U-Boot console
4848 tftpsrcp - If this is set, the value is used for TFTP's
4851 tftpdstp - If this is set, the value is used for TFTP's UDP
4852 destination port instead of the Well Know Port 69.
4854 tftpblocksize - Block size to use for TFTP transfers; if not set,
4855 we use the TFTP server's default block size
4857 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4858 seconds, minimum value is 1000 = 1 second). Defines
4859 when a packet is considered to be lost so it has to
4860 be retransmitted. The default is 5000 = 5 seconds.
4861 Lowering this value may make downloads succeed
4862 faster in networks with high packet loss rates or
4863 with unreliable TFTP servers.
4865 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4866 unit, minimum value = 0). Defines how many timeouts
4867 can happen during a single file transfer before that
4868 transfer is aborted. The default is 10, and 0 means
4869 'no timeouts allowed'. Increasing this value may help
4870 downloads succeed with high packet loss rates, or with
4871 unreliable TFTP servers or client hardware.
4873 vlan - When set to a value < 4095 the traffic over
4874 Ethernet is encapsulated/received over 802.1q
4877 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4878 Unsigned value, in milliseconds. If not set, the period will
4879 be either the default (28000), or a value based on
4880 CONFIG_NET_RETRY_COUNT, if defined. This value has
4881 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4883 The following image location variables contain the location of images
4884 used in booting. The "Image" column gives the role of the image and is
4885 not an environment variable name. The other columns are environment
4886 variable names. "File Name" gives the name of the file on a TFTP
4887 server, "RAM Address" gives the location in RAM the image will be
4888 loaded to, and "Flash Location" gives the image's address in NOR
4889 flash or offset in NAND flash.
4891 *Note* - these variables don't have to be defined for all boards, some
4892 boards currently use other variables for these purposes, and some
4893 boards use these variables for other purposes.
4895 Image File Name RAM Address Flash Location
4896 ----- --------- ----------- --------------
4897 u-boot u-boot u-boot_addr_r u-boot_addr
4898 Linux kernel bootfile kernel_addr_r kernel_addr
4899 device tree blob fdtfile fdt_addr_r fdt_addr
4900 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4902 The following environment variables may be used and automatically
4903 updated by the network boot commands ("bootp" and "rarpboot"),
4904 depending the information provided by your boot server:
4906 bootfile - see above
4907 dnsip - IP address of your Domain Name Server
4908 dnsip2 - IP address of your secondary Domain Name Server
4909 gatewayip - IP address of the Gateway (Router) to use
4910 hostname - Target hostname
4912 netmask - Subnet Mask
4913 rootpath - Pathname of the root filesystem on the NFS server
4914 serverip - see above
4917 There are two special Environment Variables:
4919 serial# - contains hardware identification information such
4920 as type string and/or serial number
4921 ethaddr - Ethernet address
4923 These variables can be set only once (usually during manufacturing of
4924 the board). U-Boot refuses to delete or overwrite these variables
4925 once they have been set once.
4928 Further special Environment Variables:
4930 ver - Contains the U-Boot version string as printed
4931 with the "version" command. This variable is
4932 readonly (see CONFIG_VERSION_VARIABLE).
4935 Please note that changes to some configuration parameters may take
4936 only effect after the next boot (yes, that's just like Windoze :-).
4939 Callback functions for environment variables:
4940 ---------------------------------------------
4942 For some environment variables, the behavior of u-boot needs to change
4943 when their values are changed. This functionality allows functions to
4944 be associated with arbitrary variables. On creation, overwrite, or
4945 deletion, the callback will provide the opportunity for some side
4946 effect to happen or for the change to be rejected.
4948 The callbacks are named and associated with a function using the
4949 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4951 These callbacks are associated with variables in one of two ways. The
4952 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4953 in the board configuration to a string that defines a list of
4954 associations. The list must be in the following format:
4956 entry = variable_name[:callback_name]
4959 If the callback name is not specified, then the callback is deleted.
4960 Spaces are also allowed anywhere in the list.
4962 Callbacks can also be associated by defining the ".callbacks" variable
4963 with the same list format above. Any association in ".callbacks" will
4964 override any association in the static list. You can define
4965 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4966 ".callbacks" environment variable in the default or embedded environment.
4968 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4969 regular expression. This allows multiple variables to be connected to
4970 the same callback without explicitly listing them all out.
4973 Command Line Parsing:
4974 =====================
4976 There are two different command line parsers available with U-Boot:
4977 the old "simple" one, and the much more powerful "hush" shell:
4979 Old, simple command line parser:
4980 --------------------------------
4982 - supports environment variables (through setenv / saveenv commands)
4983 - several commands on one line, separated by ';'
4984 - variable substitution using "... ${name} ..." syntax
4985 - special characters ('$', ';') can be escaped by prefixing with '\',
4987 setenv bootcmd bootm \${address}
4988 - You can also escape text by enclosing in single apostrophes, for example:
4989 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4994 - similar to Bourne shell, with control structures like
4995 if...then...else...fi, for...do...done; while...do...done,
4996 until...do...done, ...
4997 - supports environment ("global") variables (through setenv / saveenv
4998 commands) and local shell variables (through standard shell syntax
4999 "name=value"); only environment variables can be used with "run"
5005 (1) If a command line (or an environment variable executed by a "run"
5006 command) contains several commands separated by semicolon, and
5007 one of these commands fails, then the remaining commands will be
5010 (2) If you execute several variables with one call to run (i. e.
5011 calling run with a list of variables as arguments), any failing
5012 command will cause "run" to terminate, i. e. the remaining
5013 variables are not executed.
5015 Note for Redundant Ethernet Interfaces:
5016 =======================================
5018 Some boards come with redundant Ethernet interfaces; U-Boot supports
5019 such configurations and is capable of automatic selection of a
5020 "working" interface when needed. MAC assignment works as follows:
5022 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5023 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5024 "eth1addr" (=>eth1), "eth2addr", ...
5026 If the network interface stores some valid MAC address (for instance
5027 in SROM), this is used as default address if there is NO correspon-
5028 ding setting in the environment; if the corresponding environment
5029 variable is set, this overrides the settings in the card; that means:
5031 o If the SROM has a valid MAC address, and there is no address in the
5032 environment, the SROM's address is used.
5034 o If there is no valid address in the SROM, and a definition in the
5035 environment exists, then the value from the environment variable is
5038 o If both the SROM and the environment contain a MAC address, and
5039 both addresses are the same, this MAC address is used.
5041 o If both the SROM and the environment contain a MAC address, and the
5042 addresses differ, the value from the environment is used and a
5045 o If neither SROM nor the environment contain a MAC address, an error
5046 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5047 a random, locally-assigned MAC is used.
5049 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5050 will be programmed into hardware as part of the initialization process. This
5051 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5052 The naming convention is as follows:
5053 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5058 U-Boot is capable of booting (and performing other auxiliary operations on)
5059 images in two formats:
5061 New uImage format (FIT)
5062 -----------------------
5064 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5065 to Flattened Device Tree). It allows the use of images with multiple
5066 components (several kernels, ramdisks, etc.), with contents protected by
5067 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5073 Old image format is based on binary files which can be basically anything,
5074 preceded by a special header; see the definitions in include/image.h for
5075 details; basically, the header defines the following image properties:
5077 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5078 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5079 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5080 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5082 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5083 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5084 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5085 * Compression Type (uncompressed, gzip, bzip2)
5091 The header is marked by a special Magic Number, and both the header
5092 and the data portions of the image are secured against corruption by
5099 Although U-Boot should support any OS or standalone application
5100 easily, the main focus has always been on Linux during the design of
5103 U-Boot includes many features that so far have been part of some
5104 special "boot loader" code within the Linux kernel. Also, any
5105 "initrd" images to be used are no longer part of one big Linux image;
5106 instead, kernel and "initrd" are separate images. This implementation
5107 serves several purposes:
5109 - the same features can be used for other OS or standalone
5110 applications (for instance: using compressed images to reduce the
5111 Flash memory footprint)
5113 - it becomes much easier to port new Linux kernel versions because
5114 lots of low-level, hardware dependent stuff are done by U-Boot
5116 - the same Linux kernel image can now be used with different "initrd"
5117 images; of course this also means that different kernel images can
5118 be run with the same "initrd". This makes testing easier (you don't
5119 have to build a new "zImage.initrd" Linux image when you just
5120 change a file in your "initrd"). Also, a field-upgrade of the
5121 software is easier now.
5127 Porting Linux to U-Boot based systems:
5128 ---------------------------------------
5130 U-Boot cannot save you from doing all the necessary modifications to
5131 configure the Linux device drivers for use with your target hardware
5132 (no, we don't intend to provide a full virtual machine interface to
5135 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5137 Just make sure your machine specific header file (for instance
5138 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5139 Information structure as we define in include/asm-<arch>/u-boot.h,
5140 and make sure that your definition of IMAP_ADDR uses the same value
5141 as your U-Boot configuration in CONFIG_SYS_IMMR.
5143 Note that U-Boot now has a driver model, a unified model for drivers.
5144 If you are adding a new driver, plumb it into driver model. If there
5145 is no uclass available, you are encouraged to create one. See
5149 Configuring the Linux kernel:
5150 -----------------------------
5152 No specific requirements for U-Boot. Make sure you have some root
5153 device (initial ramdisk, NFS) for your target system.
5156 Building a Linux Image:
5157 -----------------------
5159 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5160 not used. If you use recent kernel source, a new build target
5161 "uImage" will exist which automatically builds an image usable by
5162 U-Boot. Most older kernels also have support for a "pImage" target,
5163 which was introduced for our predecessor project PPCBoot and uses a
5164 100% compatible format.
5168 make TQM850L_defconfig
5173 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5174 encapsulate a compressed Linux kernel image with header information,
5175 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5177 * build a standard "vmlinux" kernel image (in ELF binary format):
5179 * convert the kernel into a raw binary image:
5181 ${CROSS_COMPILE}-objcopy -O binary \
5182 -R .note -R .comment \
5183 -S vmlinux linux.bin
5185 * compress the binary image:
5189 * package compressed binary image for U-Boot:
5191 mkimage -A ppc -O linux -T kernel -C gzip \
5192 -a 0 -e 0 -n "Linux Kernel Image" \
5193 -d linux.bin.gz uImage
5196 The "mkimage" tool can also be used to create ramdisk images for use
5197 with U-Boot, either separated from the Linux kernel image, or
5198 combined into one file. "mkimage" encapsulates the images with a 64
5199 byte header containing information about target architecture,
5200 operating system, image type, compression method, entry points, time
5201 stamp, CRC32 checksums, etc.
5203 "mkimage" can be called in two ways: to verify existing images and
5204 print the header information, or to build new images.
5206 In the first form (with "-l" option) mkimage lists the information
5207 contained in the header of an existing U-Boot image; this includes
5208 checksum verification:
5210 tools/mkimage -l image
5211 -l ==> list image header information
5213 The second form (with "-d" option) is used to build a U-Boot image
5214 from a "data file" which is used as image payload:
5216 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5217 -n name -d data_file image
5218 -A ==> set architecture to 'arch'
5219 -O ==> set operating system to 'os'
5220 -T ==> set image type to 'type'
5221 -C ==> set compression type 'comp'
5222 -a ==> set load address to 'addr' (hex)
5223 -e ==> set entry point to 'ep' (hex)
5224 -n ==> set image name to 'name'
5225 -d ==> use image data from 'datafile'
5227 Right now, all Linux kernels for PowerPC systems use the same load
5228 address (0x00000000), but the entry point address depends on the
5231 - 2.2.x kernels have the entry point at 0x0000000C,
5232 - 2.3.x and later kernels have the entry point at 0x00000000.
5234 So a typical call to build a U-Boot image would read:
5236 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5237 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5238 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5239 > examples/uImage.TQM850L
5240 Image Name: 2.4.4 kernel for TQM850L
5241 Created: Wed Jul 19 02:34:59 2000
5242 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5243 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5244 Load Address: 0x00000000
5245 Entry Point: 0x00000000
5247 To verify the contents of the image (or check for corruption):
5249 -> tools/mkimage -l examples/uImage.TQM850L
5250 Image Name: 2.4.4 kernel for TQM850L
5251 Created: Wed Jul 19 02:34:59 2000
5252 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5253 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5254 Load Address: 0x00000000
5255 Entry Point: 0x00000000
5257 NOTE: for embedded systems where boot time is critical you can trade
5258 speed for memory and install an UNCOMPRESSED image instead: this
5259 needs more space in Flash, but boots much faster since it does not
5260 need to be uncompressed:
5262 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5263 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5264 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5265 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5266 > examples/uImage.TQM850L-uncompressed
5267 Image Name: 2.4.4 kernel for TQM850L
5268 Created: Wed Jul 19 02:34:59 2000
5269 Image Type: PowerPC Linux Kernel Image (uncompressed)
5270 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5271 Load Address: 0x00000000
5272 Entry Point: 0x00000000
5275 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5276 when your kernel is intended to use an initial ramdisk:
5278 -> tools/mkimage -n 'Simple Ramdisk Image' \
5279 > -A ppc -O linux -T ramdisk -C gzip \
5280 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5281 Image Name: Simple Ramdisk Image
5282 Created: Wed Jan 12 14:01:50 2000
5283 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5284 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5285 Load Address: 0x00000000
5286 Entry Point: 0x00000000
5288 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5289 option performs the converse operation of the mkimage's second form (the "-d"
5290 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5293 tools/dumpimage -i image -T type -p position data_file
5294 -i ==> extract from the 'image' a specific 'data_file'
5295 -T ==> set image type to 'type'
5296 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5299 Installing a Linux Image:
5300 -------------------------
5302 To downloading a U-Boot image over the serial (console) interface,
5303 you must convert the image to S-Record format:
5305 objcopy -I binary -O srec examples/image examples/image.srec
5307 The 'objcopy' does not understand the information in the U-Boot
5308 image header, so the resulting S-Record file will be relative to
5309 address 0x00000000. To load it to a given address, you need to
5310 specify the target address as 'offset' parameter with the 'loads'
5313 Example: install the image to address 0x40100000 (which on the
5314 TQM8xxL is in the first Flash bank):
5316 => erase 40100000 401FFFFF
5322 ## Ready for S-Record download ...
5323 ~>examples/image.srec
5324 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5326 15989 15990 15991 15992
5327 [file transfer complete]
5329 ## Start Addr = 0x00000000
5332 You can check the success of the download using the 'iminfo' command;
5333 this includes a checksum verification so you can be sure no data
5334 corruption happened:
5338 ## Checking Image at 40100000 ...
5339 Image Name: 2.2.13 for initrd on TQM850L
5340 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5341 Data Size: 335725 Bytes = 327 kB = 0 MB
5342 Load Address: 00000000
5343 Entry Point: 0000000c
5344 Verifying Checksum ... OK
5350 The "bootm" command is used to boot an application that is stored in
5351 memory (RAM or Flash). In case of a Linux kernel image, the contents
5352 of the "bootargs" environment variable is passed to the kernel as
5353 parameters. You can check and modify this variable using the
5354 "printenv" and "setenv" commands:
5357 => printenv bootargs
5358 bootargs=root=/dev/ram
5360 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5362 => printenv bootargs
5363 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5366 ## Booting Linux kernel at 40020000 ...
5367 Image Name: 2.2.13 for NFS on TQM850L
5368 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5369 Data Size: 381681 Bytes = 372 kB = 0 MB
5370 Load Address: 00000000
5371 Entry Point: 0000000c
5372 Verifying Checksum ... OK
5373 Uncompressing Kernel Image ... OK
5374 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
5375 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5376 time_init: decrementer frequency = 187500000/60
5377 Calibrating delay loop... 49.77 BogoMIPS
5378 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5381 If you want to boot a Linux kernel with initial RAM disk, you pass
5382 the memory addresses of both the kernel and the initrd image (PPBCOOT
5383 format!) to the "bootm" command:
5385 => imi 40100000 40200000
5387 ## Checking Image at 40100000 ...
5388 Image Name: 2.2.13 for initrd on TQM850L
5389 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5390 Data Size: 335725 Bytes = 327 kB = 0 MB
5391 Load Address: 00000000
5392 Entry Point: 0000000c
5393 Verifying Checksum ... OK
5395 ## Checking Image at 40200000 ...
5396 Image Name: Simple Ramdisk Image
5397 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5398 Data Size: 566530 Bytes = 553 kB = 0 MB
5399 Load Address: 00000000
5400 Entry Point: 00000000
5401 Verifying Checksum ... OK
5403 => bootm 40100000 40200000
5404 ## Booting Linux kernel at 40100000 ...
5405 Image Name: 2.2.13 for initrd on TQM850L
5406 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5407 Data Size: 335725 Bytes = 327 kB = 0 MB
5408 Load Address: 00000000
5409 Entry Point: 0000000c
5410 Verifying Checksum ... OK
5411 Uncompressing Kernel Image ... OK
5412 ## Loading RAMDisk Image at 40200000 ...
5413 Image Name: Simple Ramdisk Image
5414 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5415 Data Size: 566530 Bytes = 553 kB = 0 MB
5416 Load Address: 00000000
5417 Entry Point: 00000000
5418 Verifying Checksum ... OK
5419 Loading Ramdisk ... OK
5420 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
5421 Boot arguments: root=/dev/ram
5422 time_init: decrementer frequency = 187500000/60
5423 Calibrating delay loop... 49.77 BogoMIPS
5425 RAMDISK: Compressed image found at block 0
5426 VFS: Mounted root (ext2 filesystem).
5430 Boot Linux and pass a flat device tree:
5433 First, U-Boot must be compiled with the appropriate defines. See the section
5434 titled "Linux Kernel Interface" above for a more in depth explanation. The
5435 following is an example of how to start a kernel and pass an updated
5441 oft=oftrees/mpc8540ads.dtb
5442 => tftp $oftaddr $oft
5443 Speed: 1000, full duplex
5445 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5446 Filename 'oftrees/mpc8540ads.dtb'.
5447 Load address: 0x300000
5450 Bytes transferred = 4106 (100a hex)
5451 => tftp $loadaddr $bootfile
5452 Speed: 1000, full duplex
5454 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5456 Load address: 0x200000
5457 Loading:############
5459 Bytes transferred = 1029407 (fb51f hex)
5464 => bootm $loadaddr - $oftaddr
5465 ## Booting image at 00200000 ...
5466 Image Name: Linux-2.6.17-dirty
5467 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5468 Data Size: 1029343 Bytes = 1005.2 kB
5469 Load Address: 00000000
5470 Entry Point: 00000000
5471 Verifying Checksum ... OK
5472 Uncompressing Kernel Image ... OK
5473 Booting using flat device tree at 0x300000
5474 Using MPC85xx ADS machine description
5475 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5479 More About U-Boot Image Types:
5480 ------------------------------
5482 U-Boot supports the following image types:
5484 "Standalone Programs" are directly runnable in the environment
5485 provided by U-Boot; it is expected that (if they behave
5486 well) you can continue to work in U-Boot after return from
5487 the Standalone Program.
5488 "OS Kernel Images" are usually images of some Embedded OS which
5489 will take over control completely. Usually these programs
5490 will install their own set of exception handlers, device
5491 drivers, set up the MMU, etc. - this means, that you cannot
5492 expect to re-enter U-Boot except by resetting the CPU.
5493 "RAMDisk Images" are more or less just data blocks, and their
5494 parameters (address, size) are passed to an OS kernel that is
5496 "Multi-File Images" contain several images, typically an OS
5497 (Linux) kernel image and one or more data images like
5498 RAMDisks. This construct is useful for instance when you want
5499 to boot over the network using BOOTP etc., where the boot
5500 server provides just a single image file, but you want to get
5501 for instance an OS kernel and a RAMDisk image.
5503 "Multi-File Images" start with a list of image sizes, each
5504 image size (in bytes) specified by an "uint32_t" in network
5505 byte order. This list is terminated by an "(uint32_t)0".
5506 Immediately after the terminating 0 follow the images, one by
5507 one, all aligned on "uint32_t" boundaries (size rounded up to
5508 a multiple of 4 bytes).
5510 "Firmware Images" are binary images containing firmware (like
5511 U-Boot or FPGA images) which usually will be programmed to
5514 "Script files" are command sequences that will be executed by
5515 U-Boot's command interpreter; this feature is especially
5516 useful when you configure U-Boot to use a real shell (hush)
5517 as command interpreter.
5519 Booting the Linux zImage:
5520 -------------------------
5522 On some platforms, it's possible to boot Linux zImage. This is done
5523 using the "bootz" command. The syntax of "bootz" command is the same
5524 as the syntax of "bootm" command.
5526 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5527 kernel with raw initrd images. The syntax is slightly different, the
5528 address of the initrd must be augmented by it's size, in the following
5529 format: "<initrd addres>:<initrd size>".
5535 One of the features of U-Boot is that you can dynamically load and
5536 run "standalone" applications, which can use some resources of
5537 U-Boot like console I/O functions or interrupt services.
5539 Two simple examples are included with the sources:
5544 'examples/hello_world.c' contains a small "Hello World" Demo
5545 application; it is automatically compiled when you build U-Boot.
5546 It's configured to run at address 0x00040004, so you can play with it
5550 ## Ready for S-Record download ...
5551 ~>examples/hello_world.srec
5552 1 2 3 4 5 6 7 8 9 10 11 ...
5553 [file transfer complete]
5555 ## Start Addr = 0x00040004
5557 => go 40004 Hello World! This is a test.
5558 ## Starting application at 0x00040004 ...
5569 Hit any key to exit ...
5571 ## Application terminated, rc = 0x0
5573 Another example, which demonstrates how to register a CPM interrupt
5574 handler with the U-Boot code, can be found in 'examples/timer.c'.
5575 Here, a CPM timer is set up to generate an interrupt every second.
5576 The interrupt service routine is trivial, just printing a '.'
5577 character, but this is just a demo program. The application can be
5578 controlled by the following keys:
5580 ? - print current values og the CPM Timer registers
5581 b - enable interrupts and start timer
5582 e - stop timer and disable interrupts
5583 q - quit application
5586 ## Ready for S-Record download ...
5587 ~>examples/timer.srec
5588 1 2 3 4 5 6 7 8 9 10 11 ...
5589 [file transfer complete]
5591 ## Start Addr = 0x00040004
5594 ## Starting application at 0x00040004 ...
5597 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5600 [q, b, e, ?] Set interval 1000000 us
5603 [q, b, e, ?] ........
5604 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5607 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5610 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5613 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5615 [q, b, e, ?] ...Stopping timer
5617 [q, b, e, ?] ## Application terminated, rc = 0x0
5623 Over time, many people have reported problems when trying to use the
5624 "minicom" terminal emulation program for serial download. I (wd)
5625 consider minicom to be broken, and recommend not to use it. Under
5626 Unix, I recommend to use C-Kermit for general purpose use (and
5627 especially for kermit binary protocol download ("loadb" command), and
5628 use "cu" for S-Record download ("loads" command). See
5629 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5630 for help with kermit.
5633 Nevertheless, if you absolutely want to use it try adding this
5634 configuration to your "File transfer protocols" section:
5636 Name Program Name U/D FullScr IO-Red. Multi
5637 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5638 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5644 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5645 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5647 Building requires a cross environment; it is known to work on
5648 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5649 need gmake since the Makefiles are not compatible with BSD make).
5650 Note that the cross-powerpc package does not install include files;
5651 attempting to build U-Boot will fail because <machine/ansi.h> is
5652 missing. This file has to be installed and patched manually:
5654 # cd /usr/pkg/cross/powerpc-netbsd/include
5656 # ln -s powerpc machine
5657 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5658 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5660 Native builds *don't* work due to incompatibilities between native
5661 and U-Boot include files.
5663 Booting assumes that (the first part of) the image booted is a
5664 stage-2 loader which in turn loads and then invokes the kernel
5665 proper. Loader sources will eventually appear in the NetBSD source
5666 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5667 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5670 Implementation Internals:
5671 =========================
5673 The following is not intended to be a complete description of every
5674 implementation detail. However, it should help to understand the
5675 inner workings of U-Boot and make it easier to port it to custom
5679 Initial Stack, Global Data:
5680 ---------------------------
5682 The implementation of U-Boot is complicated by the fact that U-Boot
5683 starts running out of ROM (flash memory), usually without access to
5684 system RAM (because the memory controller is not initialized yet).
5685 This means that we don't have writable Data or BSS segments, and BSS
5686 is not initialized as zero. To be able to get a C environment working
5687 at all, we have to allocate at least a minimal stack. Implementation
5688 options for this are defined and restricted by the CPU used: Some CPU
5689 models provide on-chip memory (like the IMMR area on MPC8xx and
5690 MPC826x processors), on others (parts of) the data cache can be
5691 locked as (mis-) used as memory, etc.
5693 Chris Hallinan posted a good summary of these issues to the
5694 U-Boot mailing list:
5696 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5697 From: "Chris Hallinan" <clh@net1plus.com>
5698 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5701 Correct me if I'm wrong, folks, but the way I understand it
5702 is this: Using DCACHE as initial RAM for Stack, etc, does not
5703 require any physical RAM backing up the cache. The cleverness
5704 is that the cache is being used as a temporary supply of
5705 necessary storage before the SDRAM controller is setup. It's
5706 beyond the scope of this list to explain the details, but you
5707 can see how this works by studying the cache architecture and
5708 operation in the architecture and processor-specific manuals.
5710 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5711 is another option for the system designer to use as an
5712 initial stack/RAM area prior to SDRAM being available. Either
5713 option should work for you. Using CS 4 should be fine if your
5714 board designers haven't used it for something that would
5715 cause you grief during the initial boot! It is frequently not
5718 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5719 with your processor/board/system design. The default value
5720 you will find in any recent u-boot distribution in
5721 walnut.h should work for you. I'd set it to a value larger
5722 than your SDRAM module. If you have a 64MB SDRAM module, set
5723 it above 400_0000. Just make sure your board has no resources
5724 that are supposed to respond to that address! That code in
5725 start.S has been around a while and should work as is when
5726 you get the config right.
5731 It is essential to remember this, since it has some impact on the C
5732 code for the initialization procedures:
5734 * Initialized global data (data segment) is read-only. Do not attempt
5737 * Do not use any uninitialized global data (or implicitly initialized
5738 as zero data - BSS segment) at all - this is undefined, initiali-
5739 zation is performed later (when relocating to RAM).
5741 * Stack space is very limited. Avoid big data buffers or things like
5744 Having only the stack as writable memory limits means we cannot use
5745 normal global data to share information between the code. But it
5746 turned out that the implementation of U-Boot can be greatly
5747 simplified by making a global data structure (gd_t) available to all
5748 functions. We could pass a pointer to this data as argument to _all_
5749 functions, but this would bloat the code. Instead we use a feature of
5750 the GCC compiler (Global Register Variables) to share the data: we
5751 place a pointer (gd) to the global data into a register which we
5752 reserve for this purpose.
5754 When choosing a register for such a purpose we are restricted by the
5755 relevant (E)ABI specifications for the current architecture, and by
5756 GCC's implementation.
5758 For PowerPC, the following registers have specific use:
5760 R2: reserved for system use
5761 R3-R4: parameter passing and return values
5762 R5-R10: parameter passing
5763 R13: small data area pointer
5767 (U-Boot also uses R12 as internal GOT pointer. r12
5768 is a volatile register so r12 needs to be reset when
5769 going back and forth between asm and C)
5771 ==> U-Boot will use R2 to hold a pointer to the global data
5773 Note: on PPC, we could use a static initializer (since the
5774 address of the global data structure is known at compile time),
5775 but it turned out that reserving a register results in somewhat
5776 smaller code - although the code savings are not that big (on
5777 average for all boards 752 bytes for the whole U-Boot image,
5778 624 text + 127 data).
5780 On ARM, the following registers are used:
5782 R0: function argument word/integer result
5783 R1-R3: function argument word
5784 R9: platform specific
5785 R10: stack limit (used only if stack checking is enabled)
5786 R11: argument (frame) pointer
5787 R12: temporary workspace
5790 R15: program counter
5792 ==> U-Boot will use R9 to hold a pointer to the global data
5794 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5796 On Nios II, the ABI is documented here:
5797 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5799 ==> U-Boot will use gp to hold a pointer to the global data
5801 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5802 to access small data sections, so gp is free.
5804 On NDS32, the following registers are used:
5806 R0-R1: argument/return
5808 R15: temporary register for assembler
5809 R16: trampoline register
5810 R28: frame pointer (FP)
5811 R29: global pointer (GP)
5812 R30: link register (LP)
5813 R31: stack pointer (SP)
5814 PC: program counter (PC)
5816 ==> U-Boot will use R10 to hold a pointer to the global data
5818 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5819 or current versions of GCC may "optimize" the code too much.
5824 U-Boot runs in system state and uses physical addresses, i.e. the
5825 MMU is not used either for address mapping nor for memory protection.
5827 The available memory is mapped to fixed addresses using the memory
5828 controller. In this process, a contiguous block is formed for each
5829 memory type (Flash, SDRAM, SRAM), even when it consists of several
5830 physical memory banks.
5832 U-Boot is installed in the first 128 kB of the first Flash bank (on
5833 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5834 booting and sizing and initializing DRAM, the code relocates itself
5835 to the upper end of DRAM. Immediately below the U-Boot code some
5836 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5837 configuration setting]. Below that, a structure with global Board
5838 Info data is placed, followed by the stack (growing downward).
5840 Additionally, some exception handler code is copied to the low 8 kB
5841 of DRAM (0x00000000 ... 0x00001FFF).
5843 So a typical memory configuration with 16 MB of DRAM could look like
5846 0x0000 0000 Exception Vector code
5849 0x0000 2000 Free for Application Use
5855 0x00FB FF20 Monitor Stack (Growing downward)
5856 0x00FB FFAC Board Info Data and permanent copy of global data
5857 0x00FC 0000 Malloc Arena
5860 0x00FE 0000 RAM Copy of Monitor Code
5861 ... eventually: LCD or video framebuffer
5862 ... eventually: pRAM (Protected RAM - unchanged by reset)
5863 0x00FF FFFF [End of RAM]
5866 System Initialization:
5867 ----------------------
5869 In the reset configuration, U-Boot starts at the reset entry point
5870 (on most PowerPC systems at address 0x00000100). Because of the reset
5871 configuration for CS0# this is a mirror of the on board Flash memory.
5872 To be able to re-map memory U-Boot then jumps to its link address.
5873 To be able to implement the initialization code in C, a (small!)
5874 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5875 which provide such a feature like MPC8xx or MPC8260), or in a locked
5876 part of the data cache. After that, U-Boot initializes the CPU core,
5877 the caches and the SIU.
5879 Next, all (potentially) available memory banks are mapped using a
5880 preliminary mapping. For example, we put them on 512 MB boundaries
5881 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5882 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5883 programmed for SDRAM access. Using the temporary configuration, a
5884 simple memory test is run that determines the size of the SDRAM
5887 When there is more than one SDRAM bank, and the banks are of
5888 different size, the largest is mapped first. For equal size, the first
5889 bank (CS2#) is mapped first. The first mapping is always for address
5890 0x00000000, with any additional banks following immediately to create
5891 contiguous memory starting from 0.
5893 Then, the monitor installs itself at the upper end of the SDRAM area
5894 and allocates memory for use by malloc() and for the global Board
5895 Info data; also, the exception vector code is copied to the low RAM
5896 pages, and the final stack is set up.
5898 Only after this relocation will you have a "normal" C environment;
5899 until that you are restricted in several ways, mostly because you are
5900 running from ROM, and because the code will have to be relocated to a
5904 U-Boot Porting Guide:
5905 ----------------------
5907 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5911 int main(int argc, char *argv[])
5913 sighandler_t no_more_time;
5915 signal(SIGALRM, no_more_time);
5916 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5918 if (available_money > available_manpower) {
5919 Pay consultant to port U-Boot;
5923 Download latest U-Boot source;
5925 Subscribe to u-boot mailing list;
5928 email("Hi, I am new to U-Boot, how do I get started?");
5931 Read the README file in the top level directory;
5932 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5933 Read applicable doc/*.README;
5934 Read the source, Luke;
5935 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5938 if (available_money > toLocalCurrency ($2500))
5941 Add a lot of aggravation and time;
5943 if (a similar board exists) { /* hopefully... */
5944 cp -a board/<similar> board/<myboard>
5945 cp include/configs/<similar>.h include/configs/<myboard>.h
5947 Create your own board support subdirectory;
5948 Create your own board include/configs/<myboard>.h file;
5950 Edit new board/<myboard> files
5951 Edit new include/configs/<myboard>.h
5956 Add / modify source code;
5960 email("Hi, I am having problems...");
5962 Send patch file to the U-Boot email list;
5963 if (reasonable critiques)
5964 Incorporate improvements from email list code review;
5966 Defend code as written;
5972 void no_more_time (int sig)
5981 All contributions to U-Boot should conform to the Linux kernel
5982 coding style; see the file "Documentation/CodingStyle" and the script
5983 "scripts/Lindent" in your Linux kernel source directory.
5985 Source files originating from a different project (for example the
5986 MTD subsystem) are generally exempt from these guidelines and are not
5987 reformatted to ease subsequent migration to newer versions of those
5990 Please note that U-Boot is implemented in C (and to some small parts in
5991 Assembler); no C++ is used, so please do not use C++ style comments (//)
5994 Please also stick to the following formatting rules:
5995 - remove any trailing white space
5996 - use TAB characters for indentation and vertical alignment, not spaces
5997 - make sure NOT to use DOS '\r\n' line feeds
5998 - do not add more than 2 consecutive empty lines to source files
5999 - do not add trailing empty lines to source files
6001 Submissions which do not conform to the standards may be returned
6002 with a request to reformat the changes.
6008 Since the number of patches for U-Boot is growing, we need to
6009 establish some rules. Submissions which do not conform to these rules
6010 may be rejected, even when they contain important and valuable stuff.
6012 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6014 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6015 see http://lists.denx.de/mailman/listinfo/u-boot
6017 When you send a patch, please include the following information with
6020 * For bug fixes: a description of the bug and how your patch fixes
6021 this bug. Please try to include a way of demonstrating that the
6022 patch actually fixes something.
6024 * For new features: a description of the feature and your
6027 * A CHANGELOG entry as plaintext (separate from the patch)
6029 * For major contributions, add a MAINTAINERS file with your
6030 information and associated file and directory references.
6032 * When you add support for a new board, don't forget to add a
6033 maintainer e-mail address to the boards.cfg file, too.
6035 * If your patch adds new configuration options, don't forget to
6036 document these in the README file.
6038 * The patch itself. If you are using git (which is *strongly*
6039 recommended) you can easily generate the patch using the
6040 "git format-patch". If you then use "git send-email" to send it to
6041 the U-Boot mailing list, you will avoid most of the common problems
6042 with some other mail clients.
6044 If you cannot use git, use "diff -purN OLD NEW". If your version of
6045 diff does not support these options, then get the latest version of
6048 The current directory when running this command shall be the parent
6049 directory of the U-Boot source tree (i. e. please make sure that
6050 your patch includes sufficient directory information for the
6053 We prefer patches as plain text. MIME attachments are discouraged,
6054 and compressed attachments must not be used.
6056 * If one logical set of modifications affects or creates several
6057 files, all these changes shall be submitted in a SINGLE patch file.
6059 * Changesets that contain different, unrelated modifications shall be
6060 submitted as SEPARATE patches, one patch per changeset.
6065 * Before sending the patch, run the buildman script on your patched
6066 source tree and make sure that no errors or warnings are reported
6067 for any of the boards.
6069 * Keep your modifications to the necessary minimum: A patch
6070 containing several unrelated changes or arbitrary reformats will be
6071 returned with a request to re-formatting / split it.
6073 * If you modify existing code, make sure that your new code does not
6074 add to the memory footprint of the code ;-) Small is beautiful!
6075 When adding new features, these should compile conditionally only
6076 (using #ifdef), and the resulting code with the new feature
6077 disabled must not need more memory than the old code without your
6080 * Remember that there is a size limit of 100 kB per message on the
6081 u-boot mailing list. Bigger patches will be moderated. If they are
6082 reasonable and not too big, they will be acknowledged. But patches
6083 bigger than the size limit should be avoided.
projects / u-boot / blob