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_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_EXISTS * check existence of env variable
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
841 that work for multiple fs types
842 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
843 CONFIG_CMD_SAVEENV saveenv
844 CONFIG_CMD_FAT * FAT command support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GO * the 'go' command (exec code)
848 CONFIG_CMD_GREPENV * search environment
849 CONFIG_CMD_I2C * I2C serial bus support
850 CONFIG_CMD_IMI iminfo
851 CONFIG_CMD_IMLS List all images found in NOR flash
852 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
853 CONFIG_CMD_IMMAP * IMMR dump support
854 CONFIG_CMD_IOTRACE * I/O tracing for debugging
855 CONFIG_CMD_IMPORTENV * import an environment
856 CONFIG_CMD_INI * import data from an ini file into the env
857 CONFIG_CMD_IRQ * irqinfo
858 CONFIG_CMD_ITEST Integer/string test of 2 values
859 CONFIG_CMD_JFFS2 * JFFS2 Support
860 CONFIG_CMD_KGDB * kgdb
861 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
862 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
864 CONFIG_CMD_LOADB loadb
865 CONFIG_CMD_LOADS loads
866 CONFIG_CMD_MD5SUM * print md5 message digest
867 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
868 CONFIG_CMD_MEMINFO * Display detailed memory information
869 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
871 CONFIG_CMD_MEMTEST * mtest
872 CONFIG_CMD_MISC Misc functions like sleep etc
873 CONFIG_CMD_MMC * MMC memory mapped support
874 CONFIG_CMD_MII * MII utility commands
875 CONFIG_CMD_MTDPARTS * MTD partition support
876 CONFIG_CMD_NAND * NAND support
877 CONFIG_CMD_NET bootp, tftpboot, rarpboot
878 CONFIG_CMD_NFS NFS support
879 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
880 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
881 CONFIG_CMD_PCI * pciinfo
882 CONFIG_CMD_PCMCIA * PCMCIA support
883 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
885 CONFIG_CMD_PORTIO * Port I/O
886 CONFIG_CMD_READ * Read raw data from partition
887 CONFIG_CMD_REGINFO * Register dump
888 CONFIG_CMD_RUN run command in env variable
889 CONFIG_CMD_SANDBOX * sb command to access sandbox features
890 CONFIG_CMD_SAVES * save S record dump
891 CONFIG_SCSI * SCSI Support
892 CONFIG_CMD_SDRAM * print SDRAM configuration information
893 (requires CONFIG_CMD_I2C)
894 CONFIG_CMD_SETGETDCR Support for DCR Register access
896 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
897 CONFIG_CMD_SHA1SUM * print sha1 memory digest
898 (requires CONFIG_CMD_MEMORY)
899 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
900 CONFIG_CMD_SOURCE "source" command Support
901 CONFIG_CMD_SPI * SPI serial bus support
902 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
903 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
904 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
905 CONFIG_CMD_TIMER * access to the system tick timer
906 CONFIG_CMD_USB * USB support
907 CONFIG_CMD_CDP * Cisco Discover Protocol support
908 CONFIG_CMD_MFSL * Microblaze FSL support
909 CONFIG_CMD_XIMG Load part of Multi Image
910 CONFIG_CMD_UUID * Generate random UUID or GUID string
912 EXAMPLE: If you want all functions except of network
913 support you can write:
915 #include "config_cmd_all.h"
916 #undef CONFIG_CMD_NET
919 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
921 Note: Don't enable the "icache" and "dcache" commands
922 (configuration option CONFIG_CMD_CACHE) unless you know
923 what you (and your U-Boot users) are doing. Data
924 cache cannot be enabled on systems like the 8xx or
925 8260 (where accesses to the IMMR region must be
926 uncached), and it cannot be disabled on all other
927 systems where we (mis-) use the data cache to hold an
928 initial stack and some data.
931 XXX - this list needs to get updated!
933 - Removal of commands
934 If no commands are needed to boot, you can disable
935 CONFIG_CMDLINE to remove them. In this case, the command line
936 will not be available, and when U-Boot wants to execute the
937 boot command (on start-up) it will call board_run_command()
938 instead. This can reduce image size significantly for very
939 simple boot procedures.
941 - Regular expression support:
943 If this variable is defined, U-Boot is linked against
944 the SLRE (Super Light Regular Expression) library,
945 which adds regex support to some commands, as for
946 example "env grep" and "setexpr".
950 If this variable is defined, U-Boot will use a device tree
951 to configure its devices, instead of relying on statically
952 compiled #defines in the board file. This option is
953 experimental and only available on a few boards. The device
954 tree is available in the global data as gd->fdt_blob.
956 U-Boot needs to get its device tree from somewhere. This can
957 be done using one of the three options below:
960 If this variable is defined, U-Boot will embed a device tree
961 binary in its image. This device tree file should be in the
962 board directory and called <soc>-<board>.dts. The binary file
963 is then picked up in board_init_f() and made available through
964 the global data structure as gd->blob.
967 If this variable is defined, U-Boot will build a device tree
968 binary. It will be called u-boot.dtb. Architecture-specific
969 code will locate it at run-time. Generally this works by:
971 cat u-boot.bin u-boot.dtb >image.bin
973 and in fact, U-Boot does this for you, creating a file called
974 u-boot-dtb.bin which is useful in the common case. You can
975 still use the individual files if you need something more
979 If this variable is defined, U-Boot will use the device tree
980 provided by the board at runtime instead of embedding one with
981 the image. Only boards defining board_fdt_blob_setup() support
982 this option (see include/fdtdec.h file).
986 If this variable is defined, it enables watchdog
987 support for the SoC. There must be support in the SoC
988 specific code for a watchdog. For the 8xx and 8260
989 CPUs, the SIU Watchdog feature is enabled in the SYPCR
990 register. When supported for a specific SoC is
991 available, then no further board specific code should
995 When using a watchdog circuitry external to the used
996 SoC, then define this variable and provide board
997 specific code for the "hw_watchdog_reset" function.
999 CONFIG_AT91_HW_WDT_TIMEOUT
1000 specify the timeout in seconds. default 2 seconds.
1003 CONFIG_VERSION_VARIABLE
1004 If this variable is defined, an environment variable
1005 named "ver" is created by U-Boot showing the U-Boot
1006 version as printed by the "version" command.
1007 Any change to this variable will be reverted at the
1012 When CONFIG_CMD_DATE is selected, the type of the RTC
1013 has to be selected, too. Define exactly one of the
1016 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1017 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1018 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1019 CONFIG_RTC_MC146818 - use MC146818 RTC
1020 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1021 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1022 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1023 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1024 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1025 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1026 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1027 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1028 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1031 Note that if the RTC uses I2C, then the I2C interface
1032 must also be configured. See I2C Support, below.
1035 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1037 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1038 chip-ngpio pairs that tell the PCA953X driver the number of
1039 pins supported by a particular chip.
1041 Note that if the GPIO device uses I2C, then the I2C interface
1042 must also be configured. See I2C Support, below.
1045 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1046 accesses and can checksum them or write a list of them out
1047 to memory. See the 'iotrace' command for details. This is
1048 useful for testing device drivers since it can confirm that
1049 the driver behaves the same way before and after a code
1050 change. Currently this is supported on sandbox and arm. To
1051 add support for your architecture, add '#include <iotrace.h>'
1052 to the bottom of arch/<arch>/include/asm/io.h and test.
1054 Example output from the 'iotrace stats' command is below.
1055 Note that if the trace buffer is exhausted, the checksum will
1056 still continue to operate.
1059 Start: 10000000 (buffer start address)
1060 Size: 00010000 (buffer size)
1061 Offset: 00000120 (current buffer offset)
1062 Output: 10000120 (start + offset)
1063 Count: 00000018 (number of trace records)
1064 CRC32: 9526fb66 (CRC32 of all trace records)
1066 - Timestamp Support:
1068 When CONFIG_TIMESTAMP is selected, the timestamp
1069 (date and time) of an image is printed by image
1070 commands like bootm or iminfo. This option is
1071 automatically enabled when you select CONFIG_CMD_DATE .
1073 - Partition Labels (disklabels) Supported:
1074 Zero or more of the following:
1075 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1076 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1077 Intel architecture, USB sticks, etc.
1078 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1079 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1080 bootloader. Note 2TB partition limit; see
1082 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1084 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1085 CONFIG_SCSI) you must configure support for at
1086 least one non-MTD partition type as well.
1089 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1090 board configurations files but used nowhere!
1092 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1093 be performed by calling the function
1094 ide_set_reset(int reset)
1095 which has to be defined in a board specific file
1100 Set this to enable ATAPI support.
1105 Set this to enable support for disks larger than 137GB
1106 Also look at CONFIG_SYS_64BIT_LBA.
1107 Whithout these , LBA48 support uses 32bit variables and will 'only'
1108 support disks up to 2.1TB.
1110 CONFIG_SYS_64BIT_LBA:
1111 When enabled, makes the IDE subsystem use 64bit sector addresses.
1115 At the moment only there is only support for the
1116 SYM53C8XX SCSI controller; define
1117 CONFIG_SCSI_SYM53C8XX to enable it.
1119 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1120 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1121 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1122 maximum numbers of LUNs, SCSI ID's and target
1124 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1126 The environment variable 'scsidevs' is set to the number of
1127 SCSI devices found during the last scan.
1129 - NETWORK Support (PCI):
1131 Support for Intel 8254x/8257x gigabit chips.
1134 Utility code for direct access to the SPI bus on Intel 8257x.
1135 This does not do anything useful unless you set at least one
1136 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1138 CONFIG_E1000_SPI_GENERIC
1139 Allow generic access to the SPI bus on the Intel 8257x, for
1140 example with the "sspi" command.
1143 Management command for E1000 devices. When used on devices
1144 with SPI support you can reprogram the EEPROM from U-Boot.
1147 Support for Intel 82557/82559/82559ER chips.
1148 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1149 write routine for first time initialisation.
1152 Support for Digital 2114x chips.
1153 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1154 modem chip initialisation (KS8761/QS6611).
1157 Support for National dp83815 chips.
1160 Support for National dp8382[01] gigabit chips.
1162 - NETWORK Support (other):
1164 CONFIG_DRIVER_AT91EMAC
1165 Support for AT91RM9200 EMAC.
1168 Define this to use reduced MII inteface
1170 CONFIG_DRIVER_AT91EMAC_QUIET
1171 If this defined, the driver is quiet.
1172 The driver doen't show link status messages.
1174 CONFIG_CALXEDA_XGMAC
1175 Support for the Calxeda XGMAC device
1178 Support for SMSC's LAN91C96 chips.
1180 CONFIG_LAN91C96_USE_32_BIT
1181 Define this to enable 32 bit addressing
1184 Support for SMSC's LAN91C111 chip
1186 CONFIG_SMC91111_BASE
1187 Define this to hold the physical address
1188 of the device (I/O space)
1190 CONFIG_SMC_USE_32_BIT
1191 Define this if data bus is 32 bits
1193 CONFIG_SMC_USE_IOFUNCS
1194 Define this to use i/o functions instead of macros
1195 (some hardware wont work with macros)
1197 CONFIG_DRIVER_TI_EMAC
1198 Support for davinci emac
1200 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1201 Define this if you have more then 3 PHYs.
1204 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1206 CONFIG_FTGMAC100_EGIGA
1207 Define this to use GE link update with gigabit PHY.
1208 Define this if FTGMAC100 is connected to gigabit PHY.
1209 If your system has 10/100 PHY only, it might not occur
1210 wrong behavior. Because PHY usually return timeout or
1211 useless data when polling gigabit status and gigabit
1212 control registers. This behavior won't affect the
1213 correctnessof 10/100 link speed update.
1216 Support for SMSC's LAN911x and LAN921x chips
1219 Define this to hold the physical address
1220 of the device (I/O space)
1222 CONFIG_SMC911X_32_BIT
1223 Define this if data bus is 32 bits
1225 CONFIG_SMC911X_16_BIT
1226 Define this if data bus is 16 bits. If your processor
1227 automatically converts one 32 bit word to two 16 bit
1228 words you may also try CONFIG_SMC911X_32_BIT.
1231 Support for Renesas on-chip Ethernet controller
1233 CONFIG_SH_ETHER_USE_PORT
1234 Define the number of ports to be used
1236 CONFIG_SH_ETHER_PHY_ADDR
1237 Define the ETH PHY's address
1239 CONFIG_SH_ETHER_CACHE_WRITEBACK
1240 If this option is set, the driver enables cache flush.
1244 Support for PWM module on the imx6.
1248 Support TPM devices.
1250 CONFIG_TPM_TIS_INFINEON
1251 Support for Infineon i2c bus TPM devices. Only one device
1252 per system is supported at this time.
1254 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1255 Define the burst count bytes upper limit
1258 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1260 CONFIG_TPM_ST33ZP24_I2C
1261 Support for STMicroelectronics ST33ZP24 I2C devices.
1262 Requires TPM_ST33ZP24 and I2C.
1264 CONFIG_TPM_ST33ZP24_SPI
1265 Support for STMicroelectronics ST33ZP24 SPI devices.
1266 Requires TPM_ST33ZP24 and SPI.
1268 CONFIG_TPM_ATMEL_TWI
1269 Support for Atmel TWI TPM device. Requires I2C support.
1272 Support for generic parallel port TPM devices. Only one device
1273 per system is supported at this time.
1275 CONFIG_TPM_TIS_BASE_ADDRESS
1276 Base address where the generic TPM device is mapped
1277 to. Contemporary x86 systems usually map it at
1281 Add tpm monitor functions.
1282 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1283 provides monitor access to authorized functions.
1286 Define this to enable the TPM support library which provides
1287 functional interfaces to some TPM commands.
1288 Requires support for a TPM device.
1290 CONFIG_TPM_AUTH_SESSIONS
1291 Define this to enable authorized functions in the TPM library.
1292 Requires CONFIG_TPM and CONFIG_SHA1.
1295 At the moment only the UHCI host controller is
1296 supported (PIP405, MIP405, MPC5200); define
1297 CONFIG_USB_UHCI to enable it.
1298 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1299 and define CONFIG_USB_STORAGE to enable the USB
1302 Supported are USB Keyboards and USB Floppy drives
1304 MPC5200 USB requires additional defines:
1306 for 528 MHz Clock: 0x0001bbbb
1310 for differential drivers: 0x00001000
1311 for single ended drivers: 0x00005000
1312 for differential drivers on PSC3: 0x00000100
1313 for single ended drivers on PSC3: 0x00004100
1314 CONFIG_SYS_USB_EVENT_POLL
1315 May be defined to allow interrupt polling
1316 instead of using asynchronous interrupts
1318 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1319 txfilltuning field in the EHCI controller on reset.
1321 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1322 HW module registers.
1325 Define the below if you wish to use the USB console.
1326 Once firmware is rebuilt from a serial console issue the
1327 command "setenv stdin usbtty; setenv stdout usbtty" and
1328 attach your USB cable. The Unix command "dmesg" should print
1329 it has found a new device. The environment variable usbtty
1330 can be set to gserial or cdc_acm to enable your device to
1331 appear to a USB host as a Linux gserial device or a
1332 Common Device Class Abstract Control Model serial device.
1333 If you select usbtty = gserial you should be able to enumerate
1335 # modprobe usbserial vendor=0xVendorID product=0xProductID
1336 else if using cdc_acm, simply setting the environment
1337 variable usbtty to be cdc_acm should suffice. The following
1338 might be defined in YourBoardName.h
1341 Define this to build a UDC device
1344 Define this to have a tty type of device available to
1345 talk to the UDC device
1348 Define this to enable the high speed support for usb
1349 device and usbtty. If this feature is enabled, a routine
1350 int is_usbd_high_speed(void)
1351 also needs to be defined by the driver to dynamically poll
1352 whether the enumeration has succeded at high speed or full
1355 CONFIG_SYS_CONSOLE_IS_IN_ENV
1356 Define this if you want stdin, stdout &/or stderr to
1360 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1361 Derive USB clock from external clock "blah"
1362 - CONFIG_SYS_USB_EXTC_CLK 0x02
1364 If you have a USB-IF assigned VendorID then you may wish to
1365 define your own vendor specific values either in BoardName.h
1366 or directly in usbd_vendor_info.h. If you don't define
1367 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1368 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1369 should pretend to be a Linux device to it's target host.
1371 CONFIG_USBD_MANUFACTURER
1372 Define this string as the name of your company for
1373 - CONFIG_USBD_MANUFACTURER "my company"
1375 CONFIG_USBD_PRODUCT_NAME
1376 Define this string as the name of your product
1377 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1379 CONFIG_USBD_VENDORID
1380 Define this as your assigned Vendor ID from the USB
1381 Implementors Forum. This *must* be a genuine Vendor ID
1382 to avoid polluting the USB namespace.
1383 - CONFIG_USBD_VENDORID 0xFFFF
1385 CONFIG_USBD_PRODUCTID
1386 Define this as the unique Product ID
1388 - CONFIG_USBD_PRODUCTID 0xFFFF
1390 - ULPI Layer Support:
1391 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1392 the generic ULPI layer. The generic layer accesses the ULPI PHY
1393 via the platform viewport, so you need both the genric layer and
1394 the viewport enabled. Currently only Chipidea/ARC based
1395 viewport is supported.
1396 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1397 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1398 If your ULPI phy needs a different reference clock than the
1399 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1400 the appropriate value in Hz.
1403 The MMC controller on the Intel PXA is supported. To
1404 enable this define CONFIG_MMC. The MMC can be
1405 accessed from the boot prompt by mapping the device
1406 to physical memory similar to flash. Command line is
1407 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1408 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1411 Support for Renesas on-chip MMCIF controller
1413 CONFIG_SH_MMCIF_ADDR
1414 Define the base address of MMCIF registers
1417 Define the clock frequency for MMCIF
1419 CONFIG_SUPPORT_EMMC_BOOT
1420 Enable some additional features of the eMMC boot partitions.
1422 CONFIG_SUPPORT_EMMC_RPMB
1423 Enable the commands for reading, writing and programming the
1424 key for the Replay Protection Memory Block partition in eMMC.
1426 - USB Device Firmware Update (DFU) class support:
1427 CONFIG_USB_FUNCTION_DFU
1428 This enables the USB portion of the DFU USB class
1431 This enables the command "dfu" which is used to have
1432 U-Boot create a DFU class device via USB. This command
1433 requires that the "dfu_alt_info" environment variable be
1434 set and define the alt settings to expose to the host.
1437 This enables support for exposing (e)MMC devices via DFU.
1440 This enables support for exposing NAND devices via DFU.
1443 This enables support for exposing RAM via DFU.
1444 Note: DFU spec refer to non-volatile memory usage, but
1445 allow usages beyond the scope of spec - here RAM usage,
1446 one that would help mostly the developer.
1448 CONFIG_SYS_DFU_DATA_BUF_SIZE
1449 Dfu transfer uses a buffer before writing data to the
1450 raw storage device. Make the size (in bytes) of this buffer
1451 configurable. The size of this buffer is also configurable
1452 through the "dfu_bufsiz" environment variable.
1454 CONFIG_SYS_DFU_MAX_FILE_SIZE
1455 When updating files rather than the raw storage device,
1456 we use a static buffer to copy the file into and then write
1457 the buffer once we've been given the whole file. Define
1458 this to the maximum filesize (in bytes) for the buffer.
1459 Default is 4 MiB if undefined.
1461 DFU_DEFAULT_POLL_TIMEOUT
1462 Poll timeout [ms], is the timeout a device can send to the
1463 host. The host must wait for this timeout before sending
1464 a subsequent DFU_GET_STATUS request to the device.
1466 DFU_MANIFEST_POLL_TIMEOUT
1467 Poll timeout [ms], which the device sends to the host when
1468 entering dfuMANIFEST state. Host waits this timeout, before
1469 sending again an USB request to the device.
1471 - USB Device Android Fastboot support:
1472 CONFIG_USB_FUNCTION_FASTBOOT
1473 This enables the USB part of the fastboot gadget
1476 This enables the command "fastboot" which enables the Android
1477 fastboot mode for the platform's USB device. Fastboot is a USB
1478 protocol for downloading images, flashing and device control
1479 used on Android devices.
1480 See doc/README.android-fastboot for more information.
1482 CONFIG_ANDROID_BOOT_IMAGE
1483 This enables support for booting images which use the Android
1484 image format header.
1486 CONFIG_FASTBOOT_BUF_ADDR
1487 The fastboot protocol requires a large memory buffer for
1488 downloads. Define this to the starting RAM address to use for
1491 CONFIG_FASTBOOT_BUF_SIZE
1492 The fastboot protocol requires a large memory buffer for
1493 downloads. This buffer should be as large as possible for a
1494 platform. Define this to the size available RAM for fastboot.
1496 CONFIG_FASTBOOT_FLASH
1497 The fastboot protocol includes a "flash" command for writing
1498 the downloaded image to a non-volatile storage device. Define
1499 this to enable the "fastboot flash" command.
1501 CONFIG_FASTBOOT_FLASH_MMC_DEV
1502 The fastboot "flash" command requires additional information
1503 regarding the non-volatile storage device. Define this to
1504 the eMMC device that fastboot should use to store the image.
1506 CONFIG_FASTBOOT_GPT_NAME
1507 The fastboot "flash" command supports writing the downloaded
1508 image to the Protective MBR and the Primary GUID Partition
1509 Table. (Additionally, this downloaded image is post-processed
1510 to generate and write the Backup GUID Partition Table.)
1511 This occurs when the specified "partition name" on the
1512 "fastboot flash" command line matches this value.
1513 The default is "gpt" if undefined.
1515 CONFIG_FASTBOOT_MBR_NAME
1516 The fastboot "flash" command supports writing the downloaded
1518 This occurs when the "partition name" specified on the
1519 "fastboot flash" command line matches this value.
1520 If not defined the default value "mbr" is used.
1522 - Journaling Flash filesystem support:
1524 Define these for a default partition on a NAND device
1526 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1527 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1528 Define these for a default partition on a NOR device
1530 - FAT(File Allocation Table) filesystem write function support:
1533 Define this to enable support for saving memory data as a
1534 file in FAT formatted partition.
1536 This will also enable the command "fatwrite" enabling the
1537 user to write files to FAT.
1539 - FAT(File Allocation Table) filesystem cluster size:
1540 CONFIG_FS_FAT_MAX_CLUSTSIZE
1542 Define the max cluster size for fat operations else
1543 a default value of 65536 will be defined.
1546 See Kconfig help for available keyboard drivers.
1550 Define this to enable a custom keyboard support.
1551 This simply calls drv_keyboard_init() which must be
1552 defined in your board-specific files. This option is deprecated
1553 and is only used by novena. For new boards, use driver model
1558 Enable the Freescale DIU video driver. Reference boards for
1559 SOCs that have a DIU should define this macro to enable DIU
1560 support, and should also define these other macros:
1565 CONFIG_VIDEO_SW_CURSOR
1566 CONFIG_VGA_AS_SINGLE_DEVICE
1568 CONFIG_VIDEO_BMP_LOGO
1570 The DIU driver will look for the 'video-mode' environment
1571 variable, and if defined, enable the DIU as a console during
1572 boot. See the documentation file doc/README.video for a
1573 description of this variable.
1575 - LCD Support: CONFIG_LCD
1577 Define this to enable LCD support (for output to LCD
1578 display); also select one of the supported displays
1579 by defining one of these:
1583 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1585 CONFIG_NEC_NL6448AC33:
1587 NEC NL6448AC33-18. Active, color, single scan.
1589 CONFIG_NEC_NL6448BC20
1591 NEC NL6448BC20-08. 6.5", 640x480.
1592 Active, color, single scan.
1594 CONFIG_NEC_NL6448BC33_54
1596 NEC NL6448BC33-54. 10.4", 640x480.
1597 Active, color, single scan.
1601 Sharp 320x240. Active, color, single scan.
1602 It isn't 16x9, and I am not sure what it is.
1604 CONFIG_SHARP_LQ64D341
1606 Sharp LQ64D341 display, 640x480.
1607 Active, color, single scan.
1611 HLD1045 display, 640x480.
1612 Active, color, single scan.
1616 Optrex CBL50840-2 NF-FW 99 22 M5
1618 Hitachi LMG6912RPFC-00T
1622 320x240. Black & white.
1624 CONFIG_LCD_ALIGNMENT
1626 Normally the LCD is page-aligned (typically 4KB). If this is
1627 defined then the LCD will be aligned to this value instead.
1628 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1629 here, since it is cheaper to change data cache settings on
1630 a per-section basis.
1635 Sometimes, for example if the display is mounted in portrait
1636 mode or even if it's mounted landscape but rotated by 180degree,
1637 we need to rotate our content of the display relative to the
1638 framebuffer, so that user can read the messages which are
1640 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1641 initialized with a given rotation from "vl_rot" out of
1642 "vidinfo_t" which is provided by the board specific code.
1643 The value for vl_rot is coded as following (matching to
1644 fbcon=rotate:<n> linux-kernel commandline):
1645 0 = no rotation respectively 0 degree
1646 1 = 90 degree rotation
1647 2 = 180 degree rotation
1648 3 = 270 degree rotation
1650 If CONFIG_LCD_ROTATION is not defined, the console will be
1651 initialized with 0degree rotation.
1655 Support drawing of RLE8-compressed bitmaps on the LCD.
1659 Enables an 'i2c edid' command which can read EDID
1660 information over I2C from an attached LCD display.
1662 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1664 If this option is set, the environment is checked for
1665 a variable "splashimage". If found, the usual display
1666 of logo, copyright and system information on the LCD
1667 is suppressed and the BMP image at the address
1668 specified in "splashimage" is loaded instead. The
1669 console is redirected to the "nulldev", too. This
1670 allows for a "silent" boot where a splash screen is
1671 loaded very quickly after power-on.
1673 CONFIG_SPLASHIMAGE_GUARD
1675 If this option is set, then U-Boot will prevent the environment
1676 variable "splashimage" from being set to a problematic address
1677 (see doc/README.displaying-bmps).
1678 This option is useful for targets where, due to alignment
1679 restrictions, an improperly aligned BMP image will cause a data
1680 abort. If you think you will not have problems with unaligned
1681 accesses (for example because your toolchain prevents them)
1682 there is no need to set this option.
1684 CONFIG_SPLASH_SCREEN_ALIGN
1686 If this option is set the splash image can be freely positioned
1687 on the screen. Environment variable "splashpos" specifies the
1688 position as "x,y". If a positive number is given it is used as
1689 number of pixel from left/top. If a negative number is given it
1690 is used as number of pixel from right/bottom. You can also
1691 specify 'm' for centering the image.
1694 setenv splashpos m,m
1695 => image at center of screen
1697 setenv splashpos 30,20
1698 => image at x = 30 and y = 20
1700 setenv splashpos -10,m
1701 => vertically centered image
1702 at x = dspWidth - bmpWidth - 9
1704 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1706 If this option is set, additionally to standard BMP
1707 images, gzipped BMP images can be displayed via the
1708 splashscreen support or the bmp command.
1710 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1712 If this option is set, 8-bit RLE compressed BMP images
1713 can be displayed via the splashscreen support or the
1716 - Compression support:
1719 Enabled by default to support gzip compressed images.
1723 If this option is set, support for bzip2 compressed
1724 images is included. If not, only uncompressed and gzip
1725 compressed images are supported.
1727 NOTE: the bzip2 algorithm requires a lot of RAM, so
1728 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1733 If this option is set, support for lzma compressed
1736 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1737 requires an amount of dynamic memory that is given by the
1740 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1742 Where lc and lp stand for, respectively, Literal context bits
1743 and Literal pos bits.
1745 This value is upper-bounded by 14MB in the worst case. Anyway,
1746 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1747 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1748 a very small buffer.
1750 Use the lzmainfo tool to determinate the lc and lp values and
1751 then calculate the amount of needed dynamic memory (ensuring
1752 the appropriate CONFIG_SYS_MALLOC_LEN value).
1756 If this option is set, support for LZO compressed images
1762 The address of PHY on MII bus.
1764 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1766 The clock frequency of the MII bus
1770 If this option is set, support for speed/duplex
1771 detection of gigabit PHY is included.
1773 CONFIG_PHY_RESET_DELAY
1775 Some PHY like Intel LXT971A need extra delay after
1776 reset before any MII register access is possible.
1777 For such PHY, set this option to the usec delay
1778 required. (minimum 300usec for LXT971A)
1780 CONFIG_PHY_CMD_DELAY (ppc4xx)
1782 Some PHY like Intel LXT971A need extra delay after
1783 command issued before MII status register can be read
1788 Define a default value for the IP address to use for
1789 the default Ethernet interface, in case this is not
1790 determined through e.g. bootp.
1791 (Environment variable "ipaddr")
1793 - Server IP address:
1796 Defines a default value for the IP address of a TFTP
1797 server to contact when using the "tftboot" command.
1798 (Environment variable "serverip")
1800 CONFIG_KEEP_SERVERADDR
1802 Keeps the server's MAC address, in the env 'serveraddr'
1803 for passing to bootargs (like Linux's netconsole option)
1805 - Gateway IP address:
1808 Defines a default value for the IP address of the
1809 default router where packets to other networks are
1811 (Environment variable "gatewayip")
1816 Defines a default value for the subnet mask (or
1817 routing prefix) which is used to determine if an IP
1818 address belongs to the local subnet or needs to be
1819 forwarded through a router.
1820 (Environment variable "netmask")
1822 - Multicast TFTP Mode:
1825 Defines whether you want to support multicast TFTP as per
1826 rfc-2090; for example to work with atftp. Lets lots of targets
1827 tftp down the same boot image concurrently. Note: the Ethernet
1828 driver in use must provide a function: mcast() to join/leave a
1831 - BOOTP Recovery Mode:
1832 CONFIG_BOOTP_RANDOM_DELAY
1834 If you have many targets in a network that try to
1835 boot using BOOTP, you may want to avoid that all
1836 systems send out BOOTP requests at precisely the same
1837 moment (which would happen for instance at recovery
1838 from a power failure, when all systems will try to
1839 boot, thus flooding the BOOTP server. Defining
1840 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1841 inserted before sending out BOOTP requests. The
1842 following delays are inserted then:
1844 1st BOOTP request: delay 0 ... 1 sec
1845 2nd BOOTP request: delay 0 ... 2 sec
1846 3rd BOOTP request: delay 0 ... 4 sec
1848 BOOTP requests: delay 0 ... 8 sec
1850 CONFIG_BOOTP_ID_CACHE_SIZE
1852 BOOTP packets are uniquely identified using a 32-bit ID. The
1853 server will copy the ID from client requests to responses and
1854 U-Boot will use this to determine if it is the destination of
1855 an incoming response. Some servers will check that addresses
1856 aren't in use before handing them out (usually using an ARP
1857 ping) and therefore take up to a few hundred milliseconds to
1858 respond. Network congestion may also influence the time it
1859 takes for a response to make it back to the client. If that
1860 time is too long, U-Boot will retransmit requests. In order
1861 to allow earlier responses to still be accepted after these
1862 retransmissions, U-Boot's BOOTP client keeps a small cache of
1863 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1864 cache. The default is to keep IDs for up to four outstanding
1865 requests. Increasing this will allow U-Boot to accept offers
1866 from a BOOTP client in networks with unusually high latency.
1868 - DHCP Advanced Options:
1869 You can fine tune the DHCP functionality by defining
1870 CONFIG_BOOTP_* symbols:
1872 CONFIG_BOOTP_SUBNETMASK
1873 CONFIG_BOOTP_GATEWAY
1874 CONFIG_BOOTP_HOSTNAME
1875 CONFIG_BOOTP_NISDOMAIN
1876 CONFIG_BOOTP_BOOTPATH
1877 CONFIG_BOOTP_BOOTFILESIZE
1880 CONFIG_BOOTP_SEND_HOSTNAME
1881 CONFIG_BOOTP_NTPSERVER
1882 CONFIG_BOOTP_TIMEOFFSET
1883 CONFIG_BOOTP_VENDOREX
1884 CONFIG_BOOTP_MAY_FAIL
1886 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1887 environment variable, not the BOOTP server.
1889 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1890 after the configured retry count, the call will fail
1891 instead of starting over. This can be used to fail over
1892 to Link-local IP address configuration if the DHCP server
1895 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1896 serverip from a DHCP server, it is possible that more
1897 than one DNS serverip is offered to the client.
1898 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1899 serverip will be stored in the additional environment
1900 variable "dnsip2". The first DNS serverip is always
1901 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1904 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1905 to do a dynamic update of a DNS server. To do this, they
1906 need the hostname of the DHCP requester.
1907 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1908 of the "hostname" environment variable is passed as
1909 option 12 to the DHCP server.
1911 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1913 A 32bit value in microseconds for a delay between
1914 receiving a "DHCP Offer" and sending the "DHCP Request".
1915 This fixes a problem with certain DHCP servers that don't
1916 respond 100% of the time to a "DHCP request". E.g. On an
1917 AT91RM9200 processor running at 180MHz, this delay needed
1918 to be *at least* 15,000 usec before a Windows Server 2003
1919 DHCP server would reply 100% of the time. I recommend at
1920 least 50,000 usec to be safe. The alternative is to hope
1921 that one of the retries will be successful but note that
1922 the DHCP timeout and retry process takes a longer than
1925 - Link-local IP address negotiation:
1926 Negotiate with other link-local clients on the local network
1927 for an address that doesn't require explicit configuration.
1928 This is especially useful if a DHCP server cannot be guaranteed
1929 to exist in all environments that the device must operate.
1931 See doc/README.link-local for more information.
1934 CONFIG_CDP_DEVICE_ID
1936 The device id used in CDP trigger frames.
1938 CONFIG_CDP_DEVICE_ID_PREFIX
1940 A two character string which is prefixed to the MAC address
1945 A printf format string which contains the ascii name of
1946 the port. Normally is set to "eth%d" which sets
1947 eth0 for the first Ethernet, eth1 for the second etc.
1949 CONFIG_CDP_CAPABILITIES
1951 A 32bit integer which indicates the device capabilities;
1952 0x00000010 for a normal host which does not forwards.
1956 An ascii string containing the version of the software.
1960 An ascii string containing the name of the platform.
1964 A 32bit integer sent on the trigger.
1966 CONFIG_CDP_POWER_CONSUMPTION
1968 A 16bit integer containing the power consumption of the
1969 device in .1 of milliwatts.
1971 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1973 A byte containing the id of the VLAN.
1975 - Status LED: CONFIG_LED_STATUS
1977 Several configurations allow to display the current
1978 status using a LED. For instance, the LED will blink
1979 fast while running U-Boot code, stop blinking as
1980 soon as a reply to a BOOTP request was received, and
1981 start blinking slow once the Linux kernel is running
1982 (supported by a status LED driver in the Linux
1983 kernel). Defining CONFIG_LED_STATUS enables this
1988 CONFIG_LED_STATUS_GPIO
1989 The status LED can be connected to a GPIO pin.
1990 In such cases, the gpio_led driver can be used as a
1991 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1992 to include the gpio_led driver in the U-Boot binary.
1994 CONFIG_GPIO_LED_INVERTED_TABLE
1995 Some GPIO connected LEDs may have inverted polarity in which
1996 case the GPIO high value corresponds to LED off state and
1997 GPIO low value corresponds to LED on state.
1998 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1999 with a list of GPIO LEDs that have inverted polarity.
2001 - CAN Support: CONFIG_CAN_DRIVER
2003 Defining CONFIG_CAN_DRIVER enables CAN driver support
2004 on those systems that support this (optional)
2005 feature, like the TQM8xxL modules.
2007 - I2C Support: CONFIG_SYS_I2C
2009 This enable the NEW i2c subsystem, and will allow you to use
2010 i2c commands at the u-boot command line (as long as you set
2011 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2012 based realtime clock chips or other i2c devices. See
2013 common/cmd_i2c.c for a description of the command line
2016 ported i2c driver to the new framework:
2017 - drivers/i2c/soft_i2c.c:
2018 - activate first bus with CONFIG_SYS_I2C_SOFT define
2019 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2020 for defining speed and slave address
2021 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2022 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2023 for defining speed and slave address
2024 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2025 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2026 for defining speed and slave address
2027 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2028 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2029 for defining speed and slave address
2031 - drivers/i2c/fsl_i2c.c:
2032 - activate i2c driver with CONFIG_SYS_I2C_FSL
2033 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2034 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2035 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2037 - If your board supports a second fsl i2c bus, define
2038 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2039 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2040 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2043 - drivers/i2c/tegra_i2c.c:
2044 - activate this driver with CONFIG_SYS_I2C_TEGRA
2045 - This driver adds 4 i2c buses with a fix speed from
2046 100000 and the slave addr 0!
2048 - drivers/i2c/ppc4xx_i2c.c
2049 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2050 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2051 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2053 - drivers/i2c/i2c_mxc.c
2054 - activate this driver with CONFIG_SYS_I2C_MXC
2055 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2056 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2057 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2058 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2059 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2060 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2061 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2062 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2063 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2064 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2065 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2066 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2067 If those defines are not set, default value is 100000
2068 for speed, and 0 for slave.
2070 - drivers/i2c/rcar_i2c.c:
2071 - activate this driver with CONFIG_SYS_I2C_RCAR
2072 - This driver adds 4 i2c buses
2074 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2075 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2076 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2077 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2078 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2079 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2080 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2081 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2082 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2084 - drivers/i2c/sh_i2c.c:
2085 - activate this driver with CONFIG_SYS_I2C_SH
2086 - This driver adds from 2 to 5 i2c buses
2088 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2089 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2090 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2091 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2092 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2093 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2094 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2095 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2096 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2097 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2098 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2100 - drivers/i2c/omap24xx_i2c.c
2101 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2102 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2103 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2104 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2105 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2106 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2107 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2108 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2109 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2110 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2111 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2113 - drivers/i2c/zynq_i2c.c
2114 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2115 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2116 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2118 - drivers/i2c/s3c24x0_i2c.c:
2119 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2120 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2121 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2122 with a fix speed from 100000 and the slave addr 0!
2124 - drivers/i2c/ihs_i2c.c
2125 - activate this driver with CONFIG_SYS_I2C_IHS
2126 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2127 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2128 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2129 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2130 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2131 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2132 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2133 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2134 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2135 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2136 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2137 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2138 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2139 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2140 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2141 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2142 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2143 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2144 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2145 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2146 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2150 CONFIG_SYS_NUM_I2C_BUSES
2151 Hold the number of i2c buses you want to use.
2153 CONFIG_SYS_I2C_DIRECT_BUS
2154 define this, if you don't use i2c muxes on your hardware.
2155 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2158 CONFIG_SYS_I2C_MAX_HOPS
2159 define how many muxes are maximal consecutively connected
2160 on one i2c bus. If you not use i2c muxes, omit this
2163 CONFIG_SYS_I2C_BUSES
2164 hold a list of buses you want to use, only used if
2165 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2166 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2167 CONFIG_SYS_NUM_I2C_BUSES = 9:
2169 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2170 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2171 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2172 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2173 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2174 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2175 {1, {I2C_NULL_HOP}}, \
2176 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2177 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2181 bus 0 on adapter 0 without a mux
2182 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2183 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2184 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2185 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2186 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2187 bus 6 on adapter 1 without a mux
2188 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2189 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2191 If you do not have i2c muxes on your board, omit this define.
2193 - Legacy I2C Support:
2194 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2195 then the following macros need to be defined (examples are
2196 from include/configs/lwmon.h):
2200 (Optional). Any commands necessary to enable the I2C
2201 controller or configure ports.
2203 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2207 (Only for MPC8260 CPU). The I/O port to use (the code
2208 assumes both bits are on the same port). Valid values
2209 are 0..3 for ports A..D.
2213 The code necessary to make the I2C data line active
2214 (driven). If the data line is open collector, this
2217 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2221 The code necessary to make the I2C data line tri-stated
2222 (inactive). If the data line is open collector, this
2225 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2229 Code that returns true if the I2C data line is high,
2232 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2236 If <bit> is true, sets the I2C data line high. If it
2237 is false, it clears it (low).
2239 eg: #define I2C_SDA(bit) \
2240 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2241 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2245 If <bit> is true, sets the I2C clock line high. If it
2246 is false, it clears it (low).
2248 eg: #define I2C_SCL(bit) \
2249 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2250 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2254 This delay is invoked four times per clock cycle so this
2255 controls the rate of data transfer. The data rate thus
2256 is 1 / (I2C_DELAY * 4). Often defined to be something
2259 #define I2C_DELAY udelay(2)
2261 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2263 If your arch supports the generic GPIO framework (asm/gpio.h),
2264 then you may alternatively define the two GPIOs that are to be
2265 used as SCL / SDA. Any of the previous I2C_xxx macros will
2266 have GPIO-based defaults assigned to them as appropriate.
2268 You should define these to the GPIO value as given directly to
2269 the generic GPIO functions.
2271 CONFIG_SYS_I2C_INIT_BOARD
2273 When a board is reset during an i2c bus transfer
2274 chips might think that the current transfer is still
2275 in progress. On some boards it is possible to access
2276 the i2c SCLK line directly, either by using the
2277 processor pin as a GPIO or by having a second pin
2278 connected to the bus. If this option is defined a
2279 custom i2c_init_board() routine in boards/xxx/board.c
2280 is run early in the boot sequence.
2282 CONFIG_I2C_MULTI_BUS
2284 This option allows the use of multiple I2C buses, each of which
2285 must have a controller. At any point in time, only one bus is
2286 active. To switch to a different bus, use the 'i2c dev' command.
2287 Note that bus numbering is zero-based.
2289 CONFIG_SYS_I2C_NOPROBES
2291 This option specifies a list of I2C devices that will be skipped
2292 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2293 is set, specify a list of bus-device pairs. Otherwise, specify
2294 a 1D array of device addresses
2297 #undef CONFIG_I2C_MULTI_BUS
2298 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2300 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2302 #define CONFIG_I2C_MULTI_BUS
2303 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2305 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2307 CONFIG_SYS_SPD_BUS_NUM
2309 If defined, then this indicates the I2C bus number for DDR SPD.
2310 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2312 CONFIG_SYS_RTC_BUS_NUM
2314 If defined, then this indicates the I2C bus number for the RTC.
2315 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2317 CONFIG_SOFT_I2C_READ_REPEATED_START
2319 defining this will force the i2c_read() function in
2320 the soft_i2c driver to perform an I2C repeated start
2321 between writing the address pointer and reading the
2322 data. If this define is omitted the default behaviour
2323 of doing a stop-start sequence will be used. Most I2C
2324 devices can use either method, but some require one or
2327 - SPI Support: CONFIG_SPI
2329 Enables SPI driver (so far only tested with
2330 SPI EEPROM, also an instance works with Crystal A/D and
2331 D/As on the SACSng board)
2335 Enables the driver for SPI controller on SuperH. Currently
2336 only SH7757 is supported.
2340 Enables a software (bit-bang) SPI driver rather than
2341 using hardware support. This is a general purpose
2342 driver that only requires three general I/O port pins
2343 (two outputs, one input) to function. If this is
2344 defined, the board configuration must define several
2345 SPI configuration items (port pins to use, etc). For
2346 an example, see include/configs/sacsng.h.
2350 Enables a hardware SPI driver for general-purpose reads
2351 and writes. As with CONFIG_SOFT_SPI, the board configuration
2352 must define a list of chip-select function pointers.
2353 Currently supported on some MPC8xxx processors. For an
2354 example, see include/configs/mpc8349emds.h.
2358 Enables the driver for the SPI controllers on i.MX and MXC
2359 SoCs. Currently i.MX31/35/51 are supported.
2361 CONFIG_SYS_SPI_MXC_WAIT
2362 Timeout for waiting until spi transfer completed.
2363 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2365 - FPGA Support: CONFIG_FPGA
2367 Enables FPGA subsystem.
2369 CONFIG_FPGA_<vendor>
2371 Enables support for specific chip vendors.
2374 CONFIG_FPGA_<family>
2376 Enables support for FPGA family.
2377 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2381 Specify the number of FPGA devices to support.
2383 CONFIG_SYS_FPGA_PROG_FEEDBACK
2385 Enable printing of hash marks during FPGA configuration.
2387 CONFIG_SYS_FPGA_CHECK_BUSY
2389 Enable checks on FPGA configuration interface busy
2390 status by the configuration function. This option
2391 will require a board or device specific function to
2396 If defined, a function that provides delays in the FPGA
2397 configuration driver.
2399 CONFIG_SYS_FPGA_CHECK_CTRLC
2400 Allow Control-C to interrupt FPGA configuration
2402 CONFIG_SYS_FPGA_CHECK_ERROR
2404 Check for configuration errors during FPGA bitfile
2405 loading. For example, abort during Virtex II
2406 configuration if the INIT_B line goes low (which
2407 indicated a CRC error).
2409 CONFIG_SYS_FPGA_WAIT_INIT
2411 Maximum time to wait for the INIT_B line to de-assert
2412 after PROB_B has been de-asserted during a Virtex II
2413 FPGA configuration sequence. The default time is 500
2416 CONFIG_SYS_FPGA_WAIT_BUSY
2418 Maximum time to wait for BUSY to de-assert during
2419 Virtex II FPGA configuration. The default is 5 ms.
2421 CONFIG_SYS_FPGA_WAIT_CONFIG
2423 Time to wait after FPGA configuration. The default is
2426 - Configuration Management:
2429 Some SoCs need special image types (e.g. U-Boot binary
2430 with a special header) as build targets. By defining
2431 CONFIG_BUILD_TARGET in the SoC / board header, this
2432 special image will be automatically built upon calling
2437 If defined, this string will be added to the U-Boot
2438 version information (U_BOOT_VERSION)
2440 - Vendor Parameter Protection:
2442 U-Boot considers the values of the environment
2443 variables "serial#" (Board Serial Number) and
2444 "ethaddr" (Ethernet Address) to be parameters that
2445 are set once by the board vendor / manufacturer, and
2446 protects these variables from casual modification by
2447 the user. Once set, these variables are read-only,
2448 and write or delete attempts are rejected. You can
2449 change this behaviour:
2451 If CONFIG_ENV_OVERWRITE is #defined in your config
2452 file, the write protection for vendor parameters is
2453 completely disabled. Anybody can change or delete
2456 Alternatively, if you define _both_ an ethaddr in the
2457 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2458 Ethernet address is installed in the environment,
2459 which can be changed exactly ONCE by the user. [The
2460 serial# is unaffected by this, i. e. it remains
2463 The same can be accomplished in a more flexible way
2464 for any variable by configuring the type of access
2465 to allow for those variables in the ".flags" variable
2466 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2471 Define this variable to enable the reservation of
2472 "protected RAM", i. e. RAM which is not overwritten
2473 by U-Boot. Define CONFIG_PRAM to hold the number of
2474 kB you want to reserve for pRAM. You can overwrite
2475 this default value by defining an environment
2476 variable "pram" to the number of kB you want to
2477 reserve. Note that the board info structure will
2478 still show the full amount of RAM. If pRAM is
2479 reserved, a new environment variable "mem" will
2480 automatically be defined to hold the amount of
2481 remaining RAM in a form that can be passed as boot
2482 argument to Linux, for instance like that:
2484 setenv bootargs ... mem=\${mem}
2487 This way you can tell Linux not to use this memory,
2488 either, which results in a memory region that will
2489 not be affected by reboots.
2491 *WARNING* If your board configuration uses automatic
2492 detection of the RAM size, you must make sure that
2493 this memory test is non-destructive. So far, the
2494 following board configurations are known to be
2497 IVMS8, IVML24, SPD8xx, TQM8xxL,
2498 HERMES, IP860, RPXlite, LWMON,
2501 - Access to physical memory region (> 4GB)
2502 Some basic support is provided for operations on memory not
2503 normally accessible to U-Boot - e.g. some architectures
2504 support access to more than 4GB of memory on 32-bit
2505 machines using physical address extension or similar.
2506 Define CONFIG_PHYSMEM to access this basic support, which
2507 currently only supports clearing the memory.
2512 Define this variable to stop the system in case of a
2513 fatal error, so that you have to reset it manually.
2514 This is probably NOT a good idea for an embedded
2515 system where you want the system to reboot
2516 automatically as fast as possible, but it may be
2517 useful during development since you can try to debug
2518 the conditions that lead to the situation.
2520 CONFIG_NET_RETRY_COUNT
2522 This variable defines the number of retries for
2523 network operations like ARP, RARP, TFTP, or BOOTP
2524 before giving up the operation. If not defined, a
2525 default value of 5 is used.
2529 Timeout waiting for an ARP reply in milliseconds.
2533 Timeout in milliseconds used in NFS protocol.
2534 If you encounter "ERROR: Cannot umount" in nfs command,
2535 try longer timeout such as
2536 #define CONFIG_NFS_TIMEOUT 10000UL
2538 - Command Interpreter:
2539 CONFIG_AUTO_COMPLETE
2541 Enable auto completion of commands using TAB.
2543 CONFIG_SYS_PROMPT_HUSH_PS2
2545 This defines the secondary prompt string, which is
2546 printed when the command interpreter needs more input
2547 to complete a command. Usually "> ".
2551 In the current implementation, the local variables
2552 space and global environment variables space are
2553 separated. Local variables are those you define by
2554 simply typing `name=value'. To access a local
2555 variable later on, you have write `$name' or
2556 `${name}'; to execute the contents of a variable
2557 directly type `$name' at the command prompt.
2559 Global environment variables are those you use
2560 setenv/printenv to work with. To run a command stored
2561 in such a variable, you need to use the run command,
2562 and you must not use the '$' sign to access them.
2564 To store commands and special characters in a
2565 variable, please use double quotation marks
2566 surrounding the whole text of the variable, instead
2567 of the backslashes before semicolons and special
2570 - Command Line Editing and History:
2571 CONFIG_CMDLINE_EDITING
2573 Enable editing and History functions for interactive
2574 command line input operations
2576 - Command Line PS1/PS2 support:
2577 CONFIG_CMDLINE_PS_SUPPORT
2579 Enable support for changing the command prompt string
2580 at run-time. Only static string is supported so far.
2581 The string is obtained from environment variables PS1
2584 - Default Environment:
2585 CONFIG_EXTRA_ENV_SETTINGS
2587 Define this to contain any number of null terminated
2588 strings (variable = value pairs) that will be part of
2589 the default environment compiled into the boot image.
2591 For example, place something like this in your
2592 board's config file:
2594 #define CONFIG_EXTRA_ENV_SETTINGS \
2598 Warning: This method is based on knowledge about the
2599 internal format how the environment is stored by the
2600 U-Boot code. This is NOT an official, exported
2601 interface! Although it is unlikely that this format
2602 will change soon, there is no guarantee either.
2603 You better know what you are doing here.
2605 Note: overly (ab)use of the default environment is
2606 discouraged. Make sure to check other ways to preset
2607 the environment like the "source" command or the
2610 CONFIG_ENV_VARS_UBOOT_CONFIG
2612 Define this in order to add variables describing the
2613 U-Boot build configuration to the default environment.
2614 These will be named arch, cpu, board, vendor, and soc.
2616 Enabling this option will cause the following to be defined:
2624 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2626 Define this in order to add variables describing certain
2627 run-time determined information about the hardware to the
2628 environment. These will be named board_name, board_rev.
2630 CONFIG_DELAY_ENVIRONMENT
2632 Normally the environment is loaded when the board is
2633 initialised so that it is available to U-Boot. This inhibits
2634 that so that the environment is not available until
2635 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2636 this is instead controlled by the value of
2637 /config/load-environment.
2639 - DataFlash Support:
2640 CONFIG_HAS_DATAFLASH
2642 Defining this option enables DataFlash features and
2643 allows to read/write in Dataflash via the standard
2646 - Serial Flash support
2649 Defining this option enables SPI flash commands
2650 'sf probe/read/write/erase/update'.
2652 Usage requires an initial 'probe' to define the serial
2653 flash parameters, followed by read/write/erase/update
2656 The following defaults may be provided by the platform
2657 to handle the common case when only a single serial
2658 flash is present on the system.
2660 CONFIG_SF_DEFAULT_BUS Bus identifier
2661 CONFIG_SF_DEFAULT_CS Chip-select
2662 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2663 CONFIG_SF_DEFAULT_SPEED in Hz
2667 Define this option to include a destructive SPI flash
2670 CONFIG_SF_DUAL_FLASH Dual flash memories
2672 Define this option to use dual flash support where two flash
2673 memories can be connected with a given cs line.
2674 Currently Xilinx Zynq qspi supports these type of connections.
2676 - SystemACE Support:
2679 Adding this option adds support for Xilinx SystemACE
2680 chips attached via some sort of local bus. The address
2681 of the chip must also be defined in the
2682 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2684 #define CONFIG_SYSTEMACE
2685 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2687 When SystemACE support is added, the "ace" device type
2688 becomes available to the fat commands, i.e. fatls.
2690 - TFTP Fixed UDP Port:
2693 If this is defined, the environment variable tftpsrcp
2694 is used to supply the TFTP UDP source port value.
2695 If tftpsrcp isn't defined, the normal pseudo-random port
2696 number generator is used.
2698 Also, the environment variable tftpdstp is used to supply
2699 the TFTP UDP destination port value. If tftpdstp isn't
2700 defined, the normal port 69 is used.
2702 The purpose for tftpsrcp is to allow a TFTP server to
2703 blindly start the TFTP transfer using the pre-configured
2704 target IP address and UDP port. This has the effect of
2705 "punching through" the (Windows XP) firewall, allowing
2706 the remainder of the TFTP transfer to proceed normally.
2707 A better solution is to properly configure the firewall,
2708 but sometimes that is not allowed.
2713 Enable the hash verify command (hash -v). This adds to code
2716 Note: There is also a sha1sum command, which should perhaps
2717 be deprecated in favour of 'hash sha1'.
2719 - bootcount support:
2720 CONFIG_BOOTCOUNT_LIMIT
2722 This enables the bootcounter support, see:
2723 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2726 enable special bootcounter support on at91sam9xe based boards.
2728 enable special bootcounter support on da850 based boards.
2729 CONFIG_BOOTCOUNT_RAM
2730 enable support for the bootcounter in RAM
2731 CONFIG_BOOTCOUNT_I2C
2732 enable support for the bootcounter on an i2c (like RTC) device.
2733 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2734 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2736 CONFIG_BOOTCOUNT_ALEN = address len
2738 - Show boot progress:
2739 CONFIG_SHOW_BOOT_PROGRESS
2741 Defining this option allows to add some board-
2742 specific code (calling a user-provided function
2743 "show_boot_progress(int)") that enables you to show
2744 the system's boot progress on some display (for
2745 example, some LED's) on your board. At the moment,
2746 the following checkpoints are implemented:
2749 Legacy uImage format:
2752 1 common/cmd_bootm.c before attempting to boot an image
2753 -1 common/cmd_bootm.c Image header has bad magic number
2754 2 common/cmd_bootm.c Image header has correct magic number
2755 -2 common/cmd_bootm.c Image header has bad checksum
2756 3 common/cmd_bootm.c Image header has correct checksum
2757 -3 common/cmd_bootm.c Image data has bad checksum
2758 4 common/cmd_bootm.c Image data has correct checksum
2759 -4 common/cmd_bootm.c Image is for unsupported architecture
2760 5 common/cmd_bootm.c Architecture check OK
2761 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2762 6 common/cmd_bootm.c Image Type check OK
2763 -6 common/cmd_bootm.c gunzip uncompression error
2764 -7 common/cmd_bootm.c Unimplemented compression type
2765 7 common/cmd_bootm.c Uncompression OK
2766 8 common/cmd_bootm.c No uncompress/copy overwrite error
2767 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2769 9 common/image.c Start initial ramdisk verification
2770 -10 common/image.c Ramdisk header has bad magic number
2771 -11 common/image.c Ramdisk header has bad checksum
2772 10 common/image.c Ramdisk header is OK
2773 -12 common/image.c Ramdisk data has bad checksum
2774 11 common/image.c Ramdisk data has correct checksum
2775 12 common/image.c Ramdisk verification complete, start loading
2776 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2777 13 common/image.c Start multifile image verification
2778 14 common/image.c No initial ramdisk, no multifile, continue.
2780 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2782 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2783 -31 post/post.c POST test failed, detected by post_output_backlog()
2784 -32 post/post.c POST test failed, detected by post_run_single()
2786 34 common/cmd_doc.c before loading a Image from a DOC device
2787 -35 common/cmd_doc.c Bad usage of "doc" command
2788 35 common/cmd_doc.c correct usage of "doc" command
2789 -36 common/cmd_doc.c No boot device
2790 36 common/cmd_doc.c correct boot device
2791 -37 common/cmd_doc.c Unknown Chip ID on boot device
2792 37 common/cmd_doc.c correct chip ID found, device available
2793 -38 common/cmd_doc.c Read Error on boot device
2794 38 common/cmd_doc.c reading Image header from DOC device OK
2795 -39 common/cmd_doc.c Image header has bad magic number
2796 39 common/cmd_doc.c Image header has correct magic number
2797 -40 common/cmd_doc.c Error reading Image from DOC device
2798 40 common/cmd_doc.c Image header has correct magic number
2799 41 common/cmd_ide.c before loading a Image from a IDE device
2800 -42 common/cmd_ide.c Bad usage of "ide" command
2801 42 common/cmd_ide.c correct usage of "ide" command
2802 -43 common/cmd_ide.c No boot device
2803 43 common/cmd_ide.c boot device found
2804 -44 common/cmd_ide.c Device not available
2805 44 common/cmd_ide.c Device available
2806 -45 common/cmd_ide.c wrong partition selected
2807 45 common/cmd_ide.c partition selected
2808 -46 common/cmd_ide.c Unknown partition table
2809 46 common/cmd_ide.c valid partition table found
2810 -47 common/cmd_ide.c Invalid partition type
2811 47 common/cmd_ide.c correct partition type
2812 -48 common/cmd_ide.c Error reading Image Header on boot device
2813 48 common/cmd_ide.c reading Image Header from IDE device OK
2814 -49 common/cmd_ide.c Image header has bad magic number
2815 49 common/cmd_ide.c Image header has correct magic number
2816 -50 common/cmd_ide.c Image header has bad checksum
2817 50 common/cmd_ide.c Image header has correct checksum
2818 -51 common/cmd_ide.c Error reading Image from IDE device
2819 51 common/cmd_ide.c reading Image from IDE device OK
2820 52 common/cmd_nand.c before loading a Image from a NAND device
2821 -53 common/cmd_nand.c Bad usage of "nand" command
2822 53 common/cmd_nand.c correct usage of "nand" command
2823 -54 common/cmd_nand.c No boot device
2824 54 common/cmd_nand.c boot device found
2825 -55 common/cmd_nand.c Unknown Chip ID on boot device
2826 55 common/cmd_nand.c correct chip ID found, device available
2827 -56 common/cmd_nand.c Error reading Image Header on boot device
2828 56 common/cmd_nand.c reading Image Header from NAND device OK
2829 -57 common/cmd_nand.c Image header has bad magic number
2830 57 common/cmd_nand.c Image header has correct magic number
2831 -58 common/cmd_nand.c Error reading Image from NAND device
2832 58 common/cmd_nand.c reading Image from NAND device OK
2834 -60 common/env_common.c Environment has a bad CRC, using default
2836 64 net/eth.c starting with Ethernet configuration.
2837 -64 net/eth.c no Ethernet found.
2838 65 net/eth.c Ethernet found.
2840 -80 common/cmd_net.c usage wrong
2841 80 common/cmd_net.c before calling net_loop()
2842 -81 common/cmd_net.c some error in net_loop() occurred
2843 81 common/cmd_net.c net_loop() back without error
2844 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2845 82 common/cmd_net.c trying automatic boot
2846 83 common/cmd_net.c running "source" command
2847 -83 common/cmd_net.c some error in automatic boot or "source" command
2848 84 common/cmd_net.c end without errors
2853 100 common/cmd_bootm.c Kernel FIT Image has correct format
2854 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2855 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2856 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2857 102 common/cmd_bootm.c Kernel unit name specified
2858 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2859 103 common/cmd_bootm.c Found configuration node
2860 104 common/cmd_bootm.c Got kernel subimage node offset
2861 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2862 105 common/cmd_bootm.c Kernel subimage hash verification OK
2863 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2864 106 common/cmd_bootm.c Architecture check OK
2865 -106 common/cmd_bootm.c Kernel subimage has wrong type
2866 107 common/cmd_bootm.c Kernel subimage type OK
2867 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2868 108 common/cmd_bootm.c Got kernel subimage data/size
2869 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2870 -109 common/cmd_bootm.c Can't get kernel subimage type
2871 -110 common/cmd_bootm.c Can't get kernel subimage comp
2872 -111 common/cmd_bootm.c Can't get kernel subimage os
2873 -112 common/cmd_bootm.c Can't get kernel subimage load address
2874 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2876 120 common/image.c Start initial ramdisk verification
2877 -120 common/image.c Ramdisk FIT image has incorrect format
2878 121 common/image.c Ramdisk FIT image has correct format
2879 122 common/image.c No ramdisk subimage unit name, using configuration
2880 -122 common/image.c Can't get configuration for ramdisk subimage
2881 123 common/image.c Ramdisk unit name specified
2882 -124 common/image.c Can't get ramdisk subimage node offset
2883 125 common/image.c Got ramdisk subimage node offset
2884 -125 common/image.c Ramdisk subimage hash verification failed
2885 126 common/image.c Ramdisk subimage hash verification OK
2886 -126 common/image.c Ramdisk subimage for unsupported architecture
2887 127 common/image.c Architecture check OK
2888 -127 common/image.c Can't get ramdisk subimage data/size
2889 128 common/image.c Got ramdisk subimage data/size
2890 129 common/image.c Can't get ramdisk load address
2891 -129 common/image.c Got ramdisk load address
2893 -130 common/cmd_doc.c Incorrect FIT image format
2894 131 common/cmd_doc.c FIT image format OK
2896 -140 common/cmd_ide.c Incorrect FIT image format
2897 141 common/cmd_ide.c FIT image format OK
2899 -150 common/cmd_nand.c Incorrect FIT image format
2900 151 common/cmd_nand.c FIT image format OK
2902 - legacy image format:
2903 CONFIG_IMAGE_FORMAT_LEGACY
2904 enables the legacy image format support in U-Boot.
2907 enabled if CONFIG_FIT_SIGNATURE is not defined.
2909 CONFIG_DISABLE_IMAGE_LEGACY
2910 disable the legacy image format
2912 This define is introduced, as the legacy image format is
2913 enabled per default for backward compatibility.
2915 - Standalone program support:
2916 CONFIG_STANDALONE_LOAD_ADDR
2918 This option defines a board specific value for the
2919 address where standalone program gets loaded, thus
2920 overwriting the architecture dependent default
2923 - Frame Buffer Address:
2926 Define CONFIG_FB_ADDR if you want to use specific
2927 address for frame buffer. This is typically the case
2928 when using a graphics controller has separate video
2929 memory. U-Boot will then place the frame buffer at
2930 the given address instead of dynamically reserving it
2931 in system RAM by calling lcd_setmem(), which grabs
2932 the memory for the frame buffer depending on the
2933 configured panel size.
2935 Please see board_init_f function.
2937 - Automatic software updates via TFTP server
2939 CONFIG_UPDATE_TFTP_CNT_MAX
2940 CONFIG_UPDATE_TFTP_MSEC_MAX
2942 These options enable and control the auto-update feature;
2943 for a more detailed description refer to doc/README.update.
2945 - MTD Support (mtdparts command, UBI support)
2948 Adds the MTD device infrastructure from the Linux kernel.
2949 Needed for mtdparts command support.
2951 CONFIG_MTD_PARTITIONS
2953 Adds the MTD partitioning infrastructure from the Linux
2954 kernel. Needed for UBI support.
2959 Adds commands for interacting with MTD partitions formatted
2960 with the UBI flash translation layer
2962 Requires also defining CONFIG_RBTREE
2964 CONFIG_UBI_SILENCE_MSG
2966 Make the verbose messages from UBI stop printing. This leaves
2967 warnings and errors enabled.
2970 CONFIG_MTD_UBI_WL_THRESHOLD
2971 This parameter defines the maximum difference between the highest
2972 erase counter value and the lowest erase counter value of eraseblocks
2973 of UBI devices. When this threshold is exceeded, UBI starts performing
2974 wear leveling by means of moving data from eraseblock with low erase
2975 counter to eraseblocks with high erase counter.
2977 The default value should be OK for SLC NAND flashes, NOR flashes and
2978 other flashes which have eraseblock life-cycle 100000 or more.
2979 However, in case of MLC NAND flashes which typically have eraseblock
2980 life-cycle less than 10000, the threshold should be lessened (e.g.,
2981 to 128 or 256, although it does not have to be power of 2).
2985 CONFIG_MTD_UBI_BEB_LIMIT
2986 This option specifies the maximum bad physical eraseblocks UBI
2987 expects on the MTD device (per 1024 eraseblocks). If the
2988 underlying flash does not admit of bad eraseblocks (e.g. NOR
2989 flash), this value is ignored.
2991 NAND datasheets often specify the minimum and maximum NVM
2992 (Number of Valid Blocks) for the flashes' endurance lifetime.
2993 The maximum expected bad eraseblocks per 1024 eraseblocks
2994 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2995 which gives 20 for most NANDs (MaxNVB is basically the total
2996 count of eraseblocks on the chip).
2998 To put it differently, if this value is 20, UBI will try to
2999 reserve about 1.9% of physical eraseblocks for bad blocks
3000 handling. And that will be 1.9% of eraseblocks on the entire
3001 NAND chip, not just the MTD partition UBI attaches. This means
3002 that if you have, say, a NAND flash chip admits maximum 40 bad
3003 eraseblocks, and it is split on two MTD partitions of the same
3004 size, UBI will reserve 40 eraseblocks when attaching a
3009 CONFIG_MTD_UBI_FASTMAP
3010 Fastmap is a mechanism which allows attaching an UBI device
3011 in nearly constant time. Instead of scanning the whole MTD device it
3012 only has to locate a checkpoint (called fastmap) on the device.
3013 The on-flash fastmap contains all information needed to attach
3014 the device. Using fastmap makes only sense on large devices where
3015 attaching by scanning takes long. UBI will not automatically install
3016 a fastmap on old images, but you can set the UBI parameter
3017 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3018 that fastmap-enabled images are still usable with UBI implementations
3019 without fastmap support. On typical flash devices the whole fastmap
3020 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3022 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3023 Set this parameter to enable fastmap automatically on images
3027 CONFIG_MTD_UBI_FM_DEBUG
3028 Enable UBI fastmap debug
3034 Adds commands for interacting with UBI volumes formatted as
3035 UBIFS. UBIFS is read-only in u-boot.
3037 Requires UBI support as well as CONFIG_LZO
3039 CONFIG_UBIFS_SILENCE_MSG
3041 Make the verbose messages from UBIFS stop printing. This leaves
3042 warnings and errors enabled.
3046 Enable building of SPL globally.
3049 LDSCRIPT for linking the SPL binary.
3051 CONFIG_SPL_MAX_FOOTPRINT
3052 Maximum size in memory allocated to the SPL, BSS included.
3053 When defined, the linker checks that the actual memory
3054 used by SPL from _start to __bss_end does not exceed it.
3055 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3056 must not be both defined at the same time.
3059 Maximum size of the SPL image (text, data, rodata, and
3060 linker lists sections), BSS excluded.
3061 When defined, the linker checks that the actual size does
3064 CONFIG_SPL_TEXT_BASE
3065 TEXT_BASE for linking the SPL binary.
3067 CONFIG_SPL_RELOC_TEXT_BASE
3068 Address to relocate to. If unspecified, this is equal to
3069 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3071 CONFIG_SPL_BSS_START_ADDR
3072 Link address for the BSS within the SPL binary.
3074 CONFIG_SPL_BSS_MAX_SIZE
3075 Maximum size in memory allocated to the SPL BSS.
3076 When defined, the linker checks that the actual memory used
3077 by SPL from __bss_start to __bss_end does not exceed it.
3078 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3079 must not be both defined at the same time.
3082 Adress of the start of the stack SPL will use
3084 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3085 When defined, SPL will panic() if the image it has
3086 loaded does not have a signature.
3087 Defining this is useful when code which loads images
3088 in SPL cannot guarantee that absolutely all read errors
3090 An example is the LPC32XX MLC NAND driver, which will
3091 consider that a completely unreadable NAND block is bad,
3092 and thus should be skipped silently.
3094 CONFIG_SPL_RELOC_STACK
3095 Adress of the start of the stack SPL will use after
3096 relocation. If unspecified, this is equal to
3099 CONFIG_SYS_SPL_MALLOC_START
3100 Starting address of the malloc pool used in SPL.
3101 When this option is set the full malloc is used in SPL and
3102 it is set up by spl_init() and before that, the simple malloc()
3103 can be used if CONFIG_SYS_MALLOC_F is defined.
3105 CONFIG_SYS_SPL_MALLOC_SIZE
3106 The size of the malloc pool used in SPL.
3108 CONFIG_SPL_FRAMEWORK
3109 Enable the SPL framework under common/. This framework
3110 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3111 NAND loading of the Linux Kernel.
3114 Enable booting directly to an OS from SPL.
3115 See also: doc/README.falcon
3117 CONFIG_SPL_DISPLAY_PRINT
3118 For ARM, enable an optional function to print more information
3119 about the running system.
3121 CONFIG_SPL_INIT_MINIMAL
3122 Arch init code should be built for a very small image
3124 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3125 Partition on the MMC to load U-Boot from when the MMC is being
3128 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3129 Sector to load kernel uImage from when MMC is being
3130 used in raw mode (for Falcon mode)
3132 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3133 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3134 Sector and number of sectors to load kernel argument
3135 parameters from when MMC is being used in raw mode
3138 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3139 Partition on the MMC to load U-Boot from when the MMC is being
3142 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3143 Filename to read to load U-Boot when reading from filesystem
3145 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3146 Filename to read to load kernel uImage when reading
3147 from filesystem (for Falcon mode)
3149 CONFIG_SPL_FS_LOAD_ARGS_NAME
3150 Filename to read to load kernel argument parameters
3151 when reading from filesystem (for Falcon mode)
3153 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3154 Set this for NAND SPL on PPC mpc83xx targets, so that
3155 start.S waits for the rest of the SPL to load before
3156 continuing (the hardware starts execution after just
3157 loading the first page rather than the full 4K).
3159 CONFIG_SPL_SKIP_RELOCATE
3160 Avoid SPL relocation
3162 CONFIG_SPL_NAND_BASE
3163 Include nand_base.c in the SPL. Requires
3164 CONFIG_SPL_NAND_DRIVERS.
3166 CONFIG_SPL_NAND_DRIVERS
3167 SPL uses normal NAND drivers, not minimal drivers.
3170 Include standard software ECC in the SPL
3172 CONFIG_SPL_NAND_SIMPLE
3173 Support for NAND boot using simple NAND drivers that
3174 expose the cmd_ctrl() interface.
3177 Support for a lightweight UBI (fastmap) scanner and
3180 CONFIG_SPL_NAND_RAW_ONLY
3181 Support to boot only raw u-boot.bin images. Use this only
3182 if you need to save space.
3184 CONFIG_SPL_COMMON_INIT_DDR
3185 Set for common ddr init with serial presence detect in
3188 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3189 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3190 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3191 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3192 CONFIG_SYS_NAND_ECCBYTES
3193 Defines the size and behavior of the NAND that SPL uses
3196 CONFIG_SPL_NAND_BOOT
3197 Add support NAND boot
3199 CONFIG_SYS_NAND_U_BOOT_OFFS
3200 Location in NAND to read U-Boot from
3202 CONFIG_SYS_NAND_U_BOOT_DST
3203 Location in memory to load U-Boot to
3205 CONFIG_SYS_NAND_U_BOOT_SIZE
3206 Size of image to load
3208 CONFIG_SYS_NAND_U_BOOT_START
3209 Entry point in loaded image to jump to
3211 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3212 Define this if you need to first read the OOB and then the
3213 data. This is used, for example, on davinci platforms.
3215 CONFIG_SPL_OMAP3_ID_NAND
3216 Support for an OMAP3-specific set of functions to return the
3217 ID and MFR of the first attached NAND chip, if present.
3219 CONFIG_SPL_RAM_DEVICE
3220 Support for running image already present in ram, in SPL binary
3223 Image offset to which the SPL should be padded before appending
3224 the SPL payload. By default, this is defined as
3225 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3226 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3227 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3230 Final target image containing SPL and payload. Some SPLs
3231 use an arch-specific makefile fragment instead, for
3232 example if more than one image needs to be produced.
3234 CONFIG_FIT_SPL_PRINT
3235 Printing information about a FIT image adds quite a bit of
3236 code to SPL. So this is normally disabled in SPL. Use this
3237 option to re-enable it. This will affect the output of the
3238 bootm command when booting a FIT image.
3242 Enable building of TPL globally.
3245 Image offset to which the TPL should be padded before appending
3246 the TPL payload. By default, this is defined as
3247 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3248 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3249 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3251 - Interrupt support (PPC):
3253 There are common interrupt_init() and timer_interrupt()
3254 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3255 for CPU specific initialization. interrupt_init_cpu()
3256 should set decrementer_count to appropriate value. If
3257 CPU resets decrementer automatically after interrupt
3258 (ppc4xx) it should set decrementer_count to zero.
3259 timer_interrupt() calls timer_interrupt_cpu() for CPU
3260 specific handling. If board has watchdog / status_led
3261 / other_activity_monitor it works automatically from
3262 general timer_interrupt().
3265 Board initialization settings:
3266 ------------------------------
3268 During Initialization u-boot calls a number of board specific functions
3269 to allow the preparation of board specific prerequisites, e.g. pin setup
3270 before drivers are initialized. To enable these callbacks the
3271 following configuration macros have to be defined. Currently this is
3272 architecture specific, so please check arch/your_architecture/lib/board.c
3273 typically in board_init_f() and board_init_r().
3275 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3276 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3277 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3278 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3280 Configuration Settings:
3281 -----------------------
3283 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3284 Optionally it can be defined to support 64-bit memory commands.
3286 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3287 undefine this when you're short of memory.
3289 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3290 width of the commands listed in the 'help' command output.
3292 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3293 prompt for user input.
3295 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3297 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3299 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3301 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3302 the application (usually a Linux kernel) when it is
3305 - CONFIG_SYS_BAUDRATE_TABLE:
3306 List of legal baudrate settings for this board.
3308 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3309 Begin and End addresses of the area used by the
3312 - CONFIG_SYS_ALT_MEMTEST:
3313 Enable an alternate, more extensive memory test.
3315 - CONFIG_SYS_MEMTEST_SCRATCH:
3316 Scratch address used by the alternate memory test
3317 You only need to set this if address zero isn't writeable
3319 - CONFIG_SYS_MEM_RESERVE_SECURE
3320 Only implemented for ARMv8 for now.
3321 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3322 is substracted from total RAM and won't be reported to OS.
3323 This memory can be used as secure memory. A variable
3324 gd->arch.secure_ram is used to track the location. In systems
3325 the RAM base is not zero, or RAM is divided into banks,
3326 this variable needs to be recalcuated to get the address.
3328 - CONFIG_SYS_MEM_TOP_HIDE:
3329 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3330 this specified memory area will get subtracted from the top
3331 (end) of RAM and won't get "touched" at all by U-Boot. By
3332 fixing up gd->ram_size the Linux kernel should gets passed
3333 the now "corrected" memory size and won't touch it either.
3334 This should work for arch/ppc and arch/powerpc. Only Linux
3335 board ports in arch/powerpc with bootwrapper support that
3336 recalculate the memory size from the SDRAM controller setup
3337 will have to get fixed in Linux additionally.
3339 This option can be used as a workaround for the 440EPx/GRx
3340 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3343 WARNING: Please make sure that this value is a multiple of
3344 the Linux page size (normally 4k). If this is not the case,
3345 then the end address of the Linux memory will be located at a
3346 non page size aligned address and this could cause major
3349 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3350 Enable temporary baudrate change while serial download
3352 - CONFIG_SYS_SDRAM_BASE:
3353 Physical start address of SDRAM. _Must_ be 0 here.
3355 - CONFIG_SYS_FLASH_BASE:
3356 Physical start address of Flash memory.
3358 - CONFIG_SYS_MONITOR_BASE:
3359 Physical start address of boot monitor code (set by
3360 make config files to be same as the text base address
3361 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3362 CONFIG_SYS_FLASH_BASE when booting from flash.
3364 - CONFIG_SYS_MONITOR_LEN:
3365 Size of memory reserved for monitor code, used to
3366 determine _at_compile_time_ (!) if the environment is
3367 embedded within the U-Boot image, or in a separate
3370 - CONFIG_SYS_MALLOC_LEN:
3371 Size of DRAM reserved for malloc() use.
3373 - CONFIG_SYS_MALLOC_F_LEN
3374 Size of the malloc() pool for use before relocation. If
3375 this is defined, then a very simple malloc() implementation
3376 will become available before relocation. The address is just
3377 below the global data, and the stack is moved down to make
3380 This feature allocates regions with increasing addresses
3381 within the region. calloc() is supported, but realloc()
3382 is not available. free() is supported but does nothing.
3383 The memory will be freed (or in fact just forgotten) when
3384 U-Boot relocates itself.
3386 - CONFIG_SYS_MALLOC_SIMPLE
3387 Provides a simple and small malloc() and calloc() for those
3388 boards which do not use the full malloc in SPL (which is
3389 enabled with CONFIG_SYS_SPL_MALLOC_START).
3391 - CONFIG_SYS_NONCACHED_MEMORY:
3392 Size of non-cached memory area. This area of memory will be
3393 typically located right below the malloc() area and mapped
3394 uncached in the MMU. This is useful for drivers that would
3395 otherwise require a lot of explicit cache maintenance. For
3396 some drivers it's also impossible to properly maintain the
3397 cache. For example if the regions that need to be flushed
3398 are not a multiple of the cache-line size, *and* padding
3399 cannot be allocated between the regions to align them (i.e.
3400 if the HW requires a contiguous array of regions, and the
3401 size of each region is not cache-aligned), then a flush of
3402 one region may result in overwriting data that hardware has
3403 written to another region in the same cache-line. This can
3404 happen for example in network drivers where descriptors for
3405 buffers are typically smaller than the CPU cache-line (e.g.
3406 16 bytes vs. 32 or 64 bytes).
3408 Non-cached memory is only supported on 32-bit ARM at present.
3410 - CONFIG_SYS_BOOTM_LEN:
3411 Normally compressed uImages are limited to an
3412 uncompressed size of 8 MBytes. If this is not enough,
3413 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3414 to adjust this setting to your needs.
3416 - CONFIG_SYS_BOOTMAPSZ:
3417 Maximum size of memory mapped by the startup code of
3418 the Linux kernel; all data that must be processed by
3419 the Linux kernel (bd_info, boot arguments, FDT blob if
3420 used) must be put below this limit, unless "bootm_low"
3421 environment variable is defined and non-zero. In such case
3422 all data for the Linux kernel must be between "bootm_low"
3423 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3424 variable "bootm_mapsize" will override the value of
3425 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3426 then the value in "bootm_size" will be used instead.
3428 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3429 Enable initrd_high functionality. If defined then the
3430 initrd_high feature is enabled and the bootm ramdisk subcommand
3433 - CONFIG_SYS_BOOT_GET_CMDLINE:
3434 Enables allocating and saving kernel cmdline in space between
3435 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3437 - CONFIG_SYS_BOOT_GET_KBD:
3438 Enables allocating and saving a kernel copy of the bd_info in
3439 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3441 - CONFIG_SYS_MAX_FLASH_BANKS:
3442 Max number of Flash memory banks
3444 - CONFIG_SYS_MAX_FLASH_SECT:
3445 Max number of sectors on a Flash chip
3447 - CONFIG_SYS_FLASH_ERASE_TOUT:
3448 Timeout for Flash erase operations (in ms)
3450 - CONFIG_SYS_FLASH_WRITE_TOUT:
3451 Timeout for Flash write operations (in ms)
3453 - CONFIG_SYS_FLASH_LOCK_TOUT
3454 Timeout for Flash set sector lock bit operation (in ms)
3456 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3457 Timeout for Flash clear lock bits operation (in ms)
3459 - CONFIG_SYS_FLASH_PROTECTION
3460 If defined, hardware flash sectors protection is used
3461 instead of U-Boot software protection.
3463 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3465 Enable TFTP transfers directly to flash memory;
3466 without this option such a download has to be
3467 performed in two steps: (1) download to RAM, and (2)
3468 copy from RAM to flash.
3470 The two-step approach is usually more reliable, since
3471 you can check if the download worked before you erase
3472 the flash, but in some situations (when system RAM is
3473 too limited to allow for a temporary copy of the
3474 downloaded image) this option may be very useful.
3476 - CONFIG_SYS_FLASH_CFI:
3477 Define if the flash driver uses extra elements in the
3478 common flash structure for storing flash geometry.
3480 - CONFIG_FLASH_CFI_DRIVER
3481 This option also enables the building of the cfi_flash driver
3482 in the drivers directory
3484 - CONFIG_FLASH_CFI_MTD
3485 This option enables the building of the cfi_mtd driver
3486 in the drivers directory. The driver exports CFI flash
3489 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3490 Use buffered writes to flash.
3492 - CONFIG_FLASH_SPANSION_S29WS_N
3493 s29ws-n MirrorBit flash has non-standard addresses for buffered
3496 - CONFIG_SYS_FLASH_QUIET_TEST
3497 If this option is defined, the common CFI flash doesn't
3498 print it's warning upon not recognized FLASH banks. This
3499 is useful, if some of the configured banks are only
3500 optionally available.
3502 - CONFIG_FLASH_SHOW_PROGRESS
3503 If defined (must be an integer), print out countdown
3504 digits and dots. Recommended value: 45 (9..1) for 80
3505 column displays, 15 (3..1) for 40 column displays.
3507 - CONFIG_FLASH_VERIFY
3508 If defined, the content of the flash (destination) is compared
3509 against the source after the write operation. An error message
3510 will be printed when the contents are not identical.
3511 Please note that this option is useless in nearly all cases,
3512 since such flash programming errors usually are detected earlier
3513 while unprotecting/erasing/programming. Please only enable
3514 this option if you really know what you are doing.
3516 - CONFIG_SYS_RX_ETH_BUFFER:
3517 Defines the number of Ethernet receive buffers. On some
3518 Ethernet controllers it is recommended to set this value
3519 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3520 buffers can be full shortly after enabling the interface
3521 on high Ethernet traffic.
3522 Defaults to 4 if not defined.
3524 - CONFIG_ENV_MAX_ENTRIES
3526 Maximum number of entries in the hash table that is used
3527 internally to store the environment settings. The default
3528 setting is supposed to be generous and should work in most
3529 cases. This setting can be used to tune behaviour; see
3530 lib/hashtable.c for details.
3532 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3533 - CONFIG_ENV_FLAGS_LIST_STATIC
3534 Enable validation of the values given to environment variables when
3535 calling env set. Variables can be restricted to only decimal,
3536 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3537 the variables can also be restricted to IP address or MAC address.
3539 The format of the list is:
3540 type_attribute = [s|d|x|b|i|m]
3541 access_attribute = [a|r|o|c]
3542 attributes = type_attribute[access_attribute]
3543 entry = variable_name[:attributes]
3546 The type attributes are:
3547 s - String (default)
3550 b - Boolean ([1yYtT|0nNfF])
3554 The access attributes are:
3560 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3561 Define this to a list (string) to define the ".flags"
3562 environment variable in the default or embedded environment.
3564 - CONFIG_ENV_FLAGS_LIST_STATIC
3565 Define this to a list (string) to define validation that
3566 should be done if an entry is not found in the ".flags"
3567 environment variable. To override a setting in the static
3568 list, simply add an entry for the same variable name to the
3571 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3572 regular expression. This allows multiple variables to define the same
3573 flags without explicitly listing them for each variable.
3575 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3576 If defined, don't allow the -f switch to env set override variable
3580 If stdint.h is available with your toolchain you can define this
3581 option to enable it. You can provide option 'USE_STDINT=1' when
3582 building U-Boot to enable this.
3584 The following definitions that deal with the placement and management
3585 of environment data (variable area); in general, we support the
3586 following configurations:
3588 - CONFIG_BUILD_ENVCRC:
3590 Builds up envcrc with the target environment so that external utils
3591 may easily extract it and embed it in final U-Boot images.
3593 - CONFIG_ENV_IS_IN_FLASH:
3595 Define this if the environment is in flash memory.
3597 a) The environment occupies one whole flash sector, which is
3598 "embedded" in the text segment with the U-Boot code. This
3599 happens usually with "bottom boot sector" or "top boot
3600 sector" type flash chips, which have several smaller
3601 sectors at the start or the end. For instance, such a
3602 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3603 such a case you would place the environment in one of the
3604 4 kB sectors - with U-Boot code before and after it. With
3605 "top boot sector" type flash chips, you would put the
3606 environment in one of the last sectors, leaving a gap
3607 between U-Boot and the environment.
3609 - CONFIG_ENV_OFFSET:
3611 Offset of environment data (variable area) to the
3612 beginning of flash memory; for instance, with bottom boot
3613 type flash chips the second sector can be used: the offset
3614 for this sector is given here.
3616 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3620 This is just another way to specify the start address of
3621 the flash sector containing the environment (instead of
3624 - CONFIG_ENV_SECT_SIZE:
3626 Size of the sector containing the environment.
3629 b) Sometimes flash chips have few, equal sized, BIG sectors.
3630 In such a case you don't want to spend a whole sector for
3635 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3636 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3637 of this flash sector for the environment. This saves
3638 memory for the RAM copy of the environment.
3640 It may also save flash memory if you decide to use this
3641 when your environment is "embedded" within U-Boot code,
3642 since then the remainder of the flash sector could be used
3643 for U-Boot code. It should be pointed out that this is
3644 STRONGLY DISCOURAGED from a robustness point of view:
3645 updating the environment in flash makes it always
3646 necessary to erase the WHOLE sector. If something goes
3647 wrong before the contents has been restored from a copy in
3648 RAM, your target system will be dead.
3650 - CONFIG_ENV_ADDR_REDUND
3651 CONFIG_ENV_SIZE_REDUND
3653 These settings describe a second storage area used to hold
3654 a redundant copy of the environment data, so that there is
3655 a valid backup copy in case there is a power failure during
3656 a "saveenv" operation.
3658 BE CAREFUL! Any changes to the flash layout, and some changes to the
3659 source code will make it necessary to adapt <board>/u-boot.lds*
3663 - CONFIG_ENV_IS_IN_NVRAM:
3665 Define this if you have some non-volatile memory device
3666 (NVRAM, battery buffered SRAM) which you want to use for the
3672 These two #defines are used to determine the memory area you
3673 want to use for environment. It is assumed that this memory
3674 can just be read and written to, without any special
3677 BE CAREFUL! The first access to the environment happens quite early
3678 in U-Boot initialization (when we try to get the setting of for the
3679 console baudrate). You *MUST* have mapped your NVRAM area then, or
3682 Please note that even with NVRAM we still use a copy of the
3683 environment in RAM: we could work on NVRAM directly, but we want to
3684 keep settings there always unmodified except somebody uses "saveenv"
3685 to save the current settings.
3688 - CONFIG_ENV_IS_IN_EEPROM:
3690 Use this if you have an EEPROM or similar serial access
3691 device and a driver for it.
3693 - CONFIG_ENV_OFFSET:
3696 These two #defines specify the offset and size of the
3697 environment area within the total memory of your EEPROM.
3699 - CONFIG_SYS_I2C_EEPROM_ADDR:
3700 If defined, specified the chip address of the EEPROM device.
3701 The default address is zero.
3703 - CONFIG_SYS_I2C_EEPROM_BUS:
3704 If defined, specified the i2c bus of the EEPROM device.
3706 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3707 If defined, the number of bits used to address bytes in a
3708 single page in the EEPROM device. A 64 byte page, for example
3709 would require six bits.
3711 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3712 If defined, the number of milliseconds to delay between
3713 page writes. The default is zero milliseconds.
3715 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3716 The length in bytes of the EEPROM memory array address. Note
3717 that this is NOT the chip address length!
3719 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3720 EEPROM chips that implement "address overflow" are ones
3721 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3722 address and the extra bits end up in the "chip address" bit
3723 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3726 Note that we consider the length of the address field to
3727 still be one byte because the extra address bits are hidden
3728 in the chip address.
3730 - CONFIG_SYS_EEPROM_SIZE:
3731 The size in bytes of the EEPROM device.
3733 - CONFIG_ENV_EEPROM_IS_ON_I2C
3734 define this, if you have I2C and SPI activated, and your
3735 EEPROM, which holds the environment, is on the I2C bus.
3737 - CONFIG_I2C_ENV_EEPROM_BUS
3738 if you have an Environment on an EEPROM reached over
3739 I2C muxes, you can define here, how to reach this
3740 EEPROM. For example:
3742 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3744 EEPROM which holds the environment, is reached over
3745 a pca9547 i2c mux with address 0x70, channel 3.
3747 - CONFIG_ENV_IS_IN_DATAFLASH:
3749 Define this if you have a DataFlash memory device which you
3750 want to use for the environment.
3752 - CONFIG_ENV_OFFSET:
3756 These three #defines specify the offset and size of the
3757 environment area within the total memory of your DataFlash placed
3758 at the specified address.
3760 - CONFIG_ENV_IS_IN_SPI_FLASH:
3762 Define this if you have a SPI Flash memory device which you
3763 want to use for the environment.
3765 - CONFIG_ENV_OFFSET:
3768 These two #defines specify the offset and size of the
3769 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3770 aligned to an erase sector boundary.
3772 - CONFIG_ENV_SECT_SIZE:
3774 Define the SPI flash's sector size.
3776 - CONFIG_ENV_OFFSET_REDUND (optional):
3778 This setting describes a second storage area of CONFIG_ENV_SIZE
3779 size used to hold a redundant copy of the environment data, so
3780 that there is a valid backup copy in case there is a power failure
3781 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3782 aligned to an erase sector boundary.
3784 - CONFIG_ENV_SPI_BUS (optional):
3785 - CONFIG_ENV_SPI_CS (optional):
3787 Define the SPI bus and chip select. If not defined they will be 0.
3789 - CONFIG_ENV_SPI_MAX_HZ (optional):
3791 Define the SPI max work clock. If not defined then use 1MHz.
3793 - CONFIG_ENV_SPI_MODE (optional):
3795 Define the SPI work mode. If not defined then use SPI_MODE_3.
3797 - CONFIG_ENV_IS_IN_REMOTE:
3799 Define this if you have a remote memory space which you
3800 want to use for the local device's environment.
3805 These two #defines specify the address and size of the
3806 environment area within the remote memory space. The
3807 local device can get the environment from remote memory
3808 space by SRIO or PCIE links.
3810 BE CAREFUL! For some special cases, the local device can not use
3811 "saveenv" command. For example, the local device will get the
3812 environment stored in a remote NOR flash by SRIO or PCIE link,
3813 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3815 - CONFIG_ENV_IS_IN_NAND:
3817 Define this if you have a NAND device which you want to use
3818 for the environment.
3820 - CONFIG_ENV_OFFSET:
3823 These two #defines specify the offset and size of the environment
3824 area within the first NAND device. CONFIG_ENV_OFFSET must be
3825 aligned to an erase block boundary.
3827 - CONFIG_ENV_OFFSET_REDUND (optional):
3829 This setting describes a second storage area of CONFIG_ENV_SIZE
3830 size used to hold a redundant copy of the environment data, so
3831 that there is a valid backup copy in case there is a power failure
3832 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3833 aligned to an erase block boundary.
3835 - CONFIG_ENV_RANGE (optional):
3837 Specifies the length of the region in which the environment
3838 can be written. This should be a multiple of the NAND device's
3839 block size. Specifying a range with more erase blocks than
3840 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3841 the range to be avoided.
3843 - CONFIG_ENV_OFFSET_OOB (optional):
3845 Enables support for dynamically retrieving the offset of the
3846 environment from block zero's out-of-band data. The
3847 "nand env.oob" command can be used to record this offset.
3848 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3849 using CONFIG_ENV_OFFSET_OOB.
3851 - CONFIG_NAND_ENV_DST
3853 Defines address in RAM to which the nand_spl code should copy the
3854 environment. If redundant environment is used, it will be copied to
3855 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3857 - CONFIG_ENV_IS_IN_UBI:
3859 Define this if you have an UBI volume that you want to use for the
3860 environment. This has the benefit of wear-leveling the environment
3861 accesses, which is important on NAND.
3863 - CONFIG_ENV_UBI_PART:
3865 Define this to a string that is the mtd partition containing the UBI.
3867 - CONFIG_ENV_UBI_VOLUME:
3869 Define this to the name of the volume that you want to store the
3872 - CONFIG_ENV_UBI_VOLUME_REDUND:
3874 Define this to the name of another volume to store a second copy of
3875 the environment in. This will enable redundant environments in UBI.
3876 It is assumed that both volumes are in the same MTD partition.
3878 - CONFIG_UBI_SILENCE_MSG
3879 - CONFIG_UBIFS_SILENCE_MSG
3881 You will probably want to define these to avoid a really noisy system
3882 when storing the env in UBI.
3884 - CONFIG_ENV_IS_IN_FAT:
3885 Define this if you want to use the FAT file system for the environment.
3887 - FAT_ENV_INTERFACE:
3889 Define this to a string that is the name of the block device.
3891 - FAT_ENV_DEVICE_AND_PART:
3893 Define this to a string to specify the partition of the device. It can
3896 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3897 - "D:P": device D partition P. Error occurs if device D has no
3900 - "D" or "D:": device D partition 1 if device D has partition
3901 table, or the whole device D if has no partition
3903 - "D:auto": first partition in device D with bootable flag set.
3904 If none, first valid partition in device D. If no
3905 partition table then means device D.
3909 It's a string of the FAT file name. This file use to store the
3913 This should be defined. Otherwise it cannot save the environment file.
3915 - CONFIG_ENV_IS_IN_MMC:
3917 Define this if you have an MMC device which you want to use for the
3920 - CONFIG_SYS_MMC_ENV_DEV:
3922 Specifies which MMC device the environment is stored in.
3924 - CONFIG_SYS_MMC_ENV_PART (optional):
3926 Specifies which MMC partition the environment is stored in. If not
3927 set, defaults to partition 0, the user area. Common values might be
3928 1 (first MMC boot partition), 2 (second MMC boot partition).
3930 - CONFIG_ENV_OFFSET:
3933 These two #defines specify the offset and size of the environment
3934 area within the specified MMC device.
3936 If offset is positive (the usual case), it is treated as relative to
3937 the start of the MMC partition. If offset is negative, it is treated
3938 as relative to the end of the MMC partition. This can be useful if
3939 your board may be fitted with different MMC devices, which have
3940 different sizes for the MMC partitions, and you always want the
3941 environment placed at the very end of the partition, to leave the
3942 maximum possible space before it, to store other data.
3944 These two values are in units of bytes, but must be aligned to an
3945 MMC sector boundary.
3947 - CONFIG_ENV_OFFSET_REDUND (optional):
3949 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3950 hold a redundant copy of the environment data. This provides a
3951 valid backup copy in case the other copy is corrupted, e.g. due
3952 to a power failure during a "saveenv" operation.
3954 This value may also be positive or negative; this is handled in the
3955 same way as CONFIG_ENV_OFFSET.
3957 This value is also in units of bytes, but must also be aligned to
3958 an MMC sector boundary.
3960 - CONFIG_ENV_SIZE_REDUND (optional):
3962 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3963 set. If this value is set, it must be set to the same value as
3966 - CONFIG_SYS_SPI_INIT_OFFSET
3968 Defines offset to the initial SPI buffer area in DPRAM. The
3969 area is used at an early stage (ROM part) if the environment
3970 is configured to reside in the SPI EEPROM: We need a 520 byte
3971 scratch DPRAM area. It is used between the two initialization
3972 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3973 to be a good choice since it makes it far enough from the
3974 start of the data area as well as from the stack pointer.
3976 Please note that the environment is read-only until the monitor
3977 has been relocated to RAM and a RAM copy of the environment has been
3978 created; also, when using EEPROM you will have to use getenv_f()
3979 until then to read environment variables.
3981 The environment is protected by a CRC32 checksum. Before the monitor
3982 is relocated into RAM, as a result of a bad CRC you will be working
3983 with the compiled-in default environment - *silently*!!! [This is
3984 necessary, because the first environment variable we need is the
3985 "baudrate" setting for the console - if we have a bad CRC, we don't
3986 have any device yet where we could complain.]
3988 Note: once the monitor has been relocated, then it will complain if
3989 the default environment is used; a new CRC is computed as soon as you
3990 use the "saveenv" command to store a valid environment.
3992 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3993 Echo the inverted Ethernet link state to the fault LED.
3995 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3996 also needs to be defined.
3998 - CONFIG_SYS_FAULT_MII_ADDR:
3999 MII address of the PHY to check for the Ethernet link state.
4001 - CONFIG_NS16550_MIN_FUNCTIONS:
4002 Define this if you desire to only have use of the NS16550_init
4003 and NS16550_putc functions for the serial driver located at
4004 drivers/serial/ns16550.c. This option is useful for saving
4005 space for already greatly restricted images, including but not
4006 limited to NAND_SPL configurations.
4008 - CONFIG_DISPLAY_BOARDINFO
4009 Display information about the board that U-Boot is running on
4010 when U-Boot starts up. The board function checkboard() is called
4013 - CONFIG_DISPLAY_BOARDINFO_LATE
4014 Similar to the previous option, but display this information
4015 later, once stdio is running and output goes to the LCD, if
4018 - CONFIG_BOARD_SIZE_LIMIT:
4019 Maximum size of the U-Boot image. When defined, the
4020 build system checks that the actual size does not
4023 Low Level (hardware related) configuration options:
4024 ---------------------------------------------------
4026 - CONFIG_SYS_CACHELINE_SIZE:
4027 Cache Line Size of the CPU.
4029 - CONFIG_SYS_DEFAULT_IMMR:
4030 Default address of the IMMR after system reset.
4032 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4033 and RPXsuper) to be able to adjust the position of
4034 the IMMR register after a reset.
4036 - CONFIG_SYS_CCSRBAR_DEFAULT:
4037 Default (power-on reset) physical address of CCSR on Freescale
4040 - CONFIG_SYS_CCSRBAR:
4041 Virtual address of CCSR. On a 32-bit build, this is typically
4042 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4044 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4045 for cross-platform code that uses that macro instead.
4047 - CONFIG_SYS_CCSRBAR_PHYS:
4048 Physical address of CCSR. CCSR can be relocated to a new
4049 physical address, if desired. In this case, this macro should
4050 be set to that address. Otherwise, it should be set to the
4051 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4052 is typically relocated on 36-bit builds. It is recommended
4053 that this macro be defined via the _HIGH and _LOW macros:
4055 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4056 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4058 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4059 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4060 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4061 used in assembly code, so it must not contain typecasts or
4062 integer size suffixes (e.g. "ULL").
4064 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4065 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4066 used in assembly code, so it must not contain typecasts or
4067 integer size suffixes (e.g. "ULL").
4069 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4070 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4071 forced to a value that ensures that CCSR is not relocated.
4073 - Floppy Disk Support:
4074 CONFIG_SYS_FDC_DRIVE_NUMBER
4076 the default drive number (default value 0)
4078 CONFIG_SYS_ISA_IO_STRIDE
4080 defines the spacing between FDC chipset registers
4083 CONFIG_SYS_ISA_IO_OFFSET
4085 defines the offset of register from address. It
4086 depends on which part of the data bus is connected to
4087 the FDC chipset. (default value 0)
4089 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4090 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4093 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4094 fdc_hw_init() is called at the beginning of the FDC
4095 setup. fdc_hw_init() must be provided by the board
4096 source code. It is used to make hardware-dependent
4100 Most IDE controllers were designed to be connected with PCI
4101 interface. Only few of them were designed for AHB interface.
4102 When software is doing ATA command and data transfer to
4103 IDE devices through IDE-AHB controller, some additional
4104 registers accessing to these kind of IDE-AHB controller
4107 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4108 DO NOT CHANGE unless you know exactly what you're
4109 doing! (11-4) [MPC8xx/82xx systems only]
4111 - CONFIG_SYS_INIT_RAM_ADDR:
4113 Start address of memory area that can be used for
4114 initial data and stack; please note that this must be
4115 writable memory that is working WITHOUT special
4116 initialization, i. e. you CANNOT use normal RAM which
4117 will become available only after programming the
4118 memory controller and running certain initialization
4121 U-Boot uses the following memory types:
4122 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4123 - MPC824X: data cache
4124 - PPC4xx: data cache
4126 - CONFIG_SYS_GBL_DATA_OFFSET:
4128 Offset of the initial data structure in the memory
4129 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4130 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4131 data is located at the end of the available space
4132 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4133 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4134 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4135 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4138 On the MPC824X (or other systems that use the data
4139 cache for initial memory) the address chosen for
4140 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4141 point to an otherwise UNUSED address space between
4142 the top of RAM and the start of the PCI space.
4144 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4146 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4148 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4150 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4152 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4154 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4156 - CONFIG_SYS_OR_TIMING_SDRAM:
4159 - CONFIG_SYS_MAMR_PTA:
4160 periodic timer for refresh
4162 - CONFIG_SYS_DER: Debug Event Register (37-47)
4164 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4165 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4166 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4167 CONFIG_SYS_BR1_PRELIM:
4168 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4170 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4171 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4172 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4173 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4175 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4176 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4177 Machine Mode Register and Memory Periodic Timer
4178 Prescaler definitions (SDRAM timing)
4180 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4181 enable I2C microcode relocation patch (MPC8xx);
4182 define relocation offset in DPRAM [DSP2]
4184 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4185 enable SMC microcode relocation patch (MPC8xx);
4186 define relocation offset in DPRAM [SMC1]
4188 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4189 enable SPI microcode relocation patch (MPC8xx);
4190 define relocation offset in DPRAM [SCC4]
4192 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4193 Offset of the bootmode word in DPRAM used by post
4194 (Power On Self Tests). This definition overrides
4195 #define'd default value in commproc.h resp.
4198 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4199 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4200 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4201 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4202 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4203 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4204 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4205 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4206 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4208 - CONFIG_PCI_DISABLE_PCIE:
4209 Disable PCI-Express on systems where it is supported but not
4212 - CONFIG_PCI_ENUM_ONLY
4213 Only scan through and get the devices on the buses.
4214 Don't do any setup work, presumably because someone or
4215 something has already done it, and we don't need to do it
4216 a second time. Useful for platforms that are pre-booted
4217 by coreboot or similar.
4219 - CONFIG_PCI_INDIRECT_BRIDGE:
4220 Enable support for indirect PCI bridges.
4223 Chip has SRIO or not
4226 Board has SRIO 1 port available
4229 Board has SRIO 2 port available
4231 - CONFIG_SRIO_PCIE_BOOT_MASTER
4232 Board can support master function for Boot from SRIO and PCIE
4234 - CONFIG_SYS_SRIOn_MEM_VIRT:
4235 Virtual Address of SRIO port 'n' memory region
4237 - CONFIG_SYS_SRIOn_MEM_PHYS:
4238 Physical Address of SRIO port 'n' memory region
4240 - CONFIG_SYS_SRIOn_MEM_SIZE:
4241 Size of SRIO port 'n' memory region
4243 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4244 Defined to tell the NAND controller that the NAND chip is using
4246 Not all NAND drivers use this symbol.
4247 Example of drivers that use it:
4248 - drivers/mtd/nand/ndfc.c
4249 - drivers/mtd/nand/mxc_nand.c
4251 - CONFIG_SYS_NDFC_EBC0_CFG
4252 Sets the EBC0_CFG register for the NDFC. If not defined
4253 a default value will be used.
4256 Get DDR timing information from an I2C EEPROM. Common
4257 with pluggable memory modules such as SODIMMs
4260 I2C address of the SPD EEPROM
4262 - CONFIG_SYS_SPD_BUS_NUM
4263 If SPD EEPROM is on an I2C bus other than the first
4264 one, specify here. Note that the value must resolve
4265 to something your driver can deal with.
4267 - CONFIG_SYS_DDR_RAW_TIMING
4268 Get DDR timing information from other than SPD. Common with
4269 soldered DDR chips onboard without SPD. DDR raw timing
4270 parameters are extracted from datasheet and hard-coded into
4271 header files or board specific files.
4273 - CONFIG_FSL_DDR_INTERACTIVE
4274 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4276 - CONFIG_FSL_DDR_SYNC_REFRESH
4277 Enable sync of refresh for multiple controllers.
4279 - CONFIG_FSL_DDR_BIST
4280 Enable built-in memory test for Freescale DDR controllers.
4282 - CONFIG_SYS_83XX_DDR_USES_CS0
4283 Only for 83xx systems. If specified, then DDR should
4284 be configured using CS0 and CS1 instead of CS2 and CS3.
4286 - CONFIG_ETHER_ON_FEC[12]
4287 Define to enable FEC[12] on a 8xx series processor.
4289 - CONFIG_FEC[12]_PHY
4290 Define to the hardcoded PHY address which corresponds
4291 to the given FEC; i. e.
4292 #define CONFIG_FEC1_PHY 4
4293 means that the PHY with address 4 is connected to FEC1
4295 When set to -1, means to probe for first available.
4297 - CONFIG_FEC[12]_PHY_NORXERR
4298 The PHY does not have a RXERR line (RMII only).
4299 (so program the FEC to ignore it).
4302 Enable RMII mode for all FECs.
4303 Note that this is a global option, we can't
4304 have one FEC in standard MII mode and another in RMII mode.
4306 - CONFIG_CRC32_VERIFY
4307 Add a verify option to the crc32 command.
4310 => crc32 -v <address> <count> <crc32>
4312 Where address/count indicate a memory area
4313 and crc32 is the correct crc32 which the
4317 Add the "loopw" memory command. This only takes effect if
4318 the memory commands are activated globally (CONFIG_CMD_MEM).
4321 Add the "mdc" and "mwc" memory commands. These are cyclic
4326 This command will print 4 bytes (10,11,12,13) each 500 ms.
4328 => mwc.l 100 12345678 10
4329 This command will write 12345678 to address 100 all 10 ms.
4331 This only takes effect if the memory commands are activated
4332 globally (CONFIG_CMD_MEM).
4334 - CONFIG_SKIP_LOWLEVEL_INIT
4335 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4336 low level initializations (like setting up the memory
4337 controller) are omitted and/or U-Boot does not
4338 relocate itself into RAM.
4340 Normally this variable MUST NOT be defined. The only
4341 exception is when U-Boot is loaded (to RAM) by some
4342 other boot loader or by a debugger which performs
4343 these initializations itself.
4345 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4346 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4347 to be skipped. The normal CP15 init (such as enabling the
4348 instruction cache) is still performed.
4351 Modifies the behaviour of start.S when compiling a loader
4352 that is executed before the actual U-Boot. E.g. when
4353 compiling a NAND SPL.
4356 Modifies the behaviour of start.S when compiling a loader
4357 that is executed after the SPL and before the actual U-Boot.
4358 It is loaded by the SPL.
4360 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4361 Only for 85xx systems. If this variable is specified, the section
4362 .resetvec is not kept and the section .bootpg is placed in the
4363 previous 4k of the .text section.
4365 - CONFIG_ARCH_MAP_SYSMEM
4366 Generally U-Boot (and in particular the md command) uses
4367 effective address. It is therefore not necessary to regard
4368 U-Boot address as virtual addresses that need to be translated
4369 to physical addresses. However, sandbox requires this, since
4370 it maintains its own little RAM buffer which contains all
4371 addressable memory. This option causes some memory accesses
4372 to be mapped through map_sysmem() / unmap_sysmem().
4374 - CONFIG_X86_RESET_VECTOR
4375 If defined, the x86 reset vector code is included. This is not
4376 needed when U-Boot is running from Coreboot.
4378 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4379 Enables the RTC32K OSC on AM33xx based plattforms
4381 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4382 Option to disable subpage write in NAND driver
4383 driver that uses this:
4384 drivers/mtd/nand/davinci_nand.c
4386 Freescale QE/FMAN Firmware Support:
4387 -----------------------------------
4389 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4390 loading of "firmware", which is encoded in the QE firmware binary format.
4391 This firmware often needs to be loaded during U-Boot booting, so macros
4392 are used to identify the storage device (NOR flash, SPI, etc) and the address
4395 - CONFIG_SYS_FMAN_FW_ADDR
4396 The address in the storage device where the FMAN microcode is located. The
4397 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4400 - CONFIG_SYS_QE_FW_ADDR
4401 The address in the storage device where the QE microcode is located. The
4402 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4405 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4406 The maximum possible size of the firmware. The firmware binary format
4407 has a field that specifies the actual size of the firmware, but it
4408 might not be possible to read any part of the firmware unless some
4409 local storage is allocated to hold the entire firmware first.
4411 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4412 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4413 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4414 virtual address in NOR flash.
4416 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4417 Specifies that QE/FMAN firmware is located in NAND flash.
4418 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4420 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4421 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4422 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4424 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4425 Specifies that QE/FMAN firmware is located in the remote (master)
4426 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4427 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4428 window->master inbound window->master LAW->the ucode address in
4429 master's memory space.
4431 Freescale Layerscape Management Complex Firmware Support:
4432 ---------------------------------------------------------
4433 The Freescale Layerscape Management Complex (MC) supports the loading of
4435 This firmware often needs to be loaded during U-Boot booting, so macros
4436 are used to identify the storage device (NOR flash, SPI, etc) and the address
4439 - CONFIG_FSL_MC_ENET
4440 Enable the MC driver for Layerscape SoCs.
4442 Freescale Layerscape Debug Server Support:
4443 -------------------------------------------
4444 The Freescale Layerscape Debug Server Support supports the loading of
4445 "Debug Server firmware" and triggering SP boot-rom.
4446 This firmware often needs to be loaded during U-Boot booting.
4448 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4449 Define alignment of reserved memory MC requires
4454 In order to achieve reproducible builds, timestamps used in the U-Boot build
4455 process have to be set to a fixed value.
4457 This is done using the SOURCE_DATE_EPOCH environment variable.
4458 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4459 option for U-Boot or an environment variable in U-Boot.
4461 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4463 Building the Software:
4464 ======================
4466 Building U-Boot has been tested in several native build environments
4467 and in many different cross environments. Of course we cannot support
4468 all possibly existing versions of cross development tools in all
4469 (potentially obsolete) versions. In case of tool chain problems we
4470 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4471 which is extensively used to build and test U-Boot.
4473 If you are not using a native environment, it is assumed that you
4474 have GNU cross compiling tools available in your path. In this case,
4475 you must set the environment variable CROSS_COMPILE in your shell.
4476 Note that no changes to the Makefile or any other source files are
4477 necessary. For example using the ELDK on a 4xx CPU, please enter:
4479 $ CROSS_COMPILE=ppc_4xx-
4480 $ export CROSS_COMPILE
4482 Note: If you wish to generate Windows versions of the utilities in
4483 the tools directory you can use the MinGW toolchain
4484 (http://www.mingw.org). Set your HOST tools to the MinGW
4485 toolchain and execute 'make tools'. For example:
4487 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4489 Binaries such as tools/mkimage.exe will be created which can
4490 be executed on computers running Windows.
4492 U-Boot is intended to be simple to build. After installing the
4493 sources you must configure U-Boot for one specific board type. This
4498 where "NAME_defconfig" is the name of one of the existing configu-
4499 rations; see boards.cfg for supported names.
4501 Note: for some board special configuration names may exist; check if
4502 additional information is available from the board vendor; for
4503 instance, the TQM823L systems are available without (standard)
4504 or with LCD support. You can select such additional "features"
4505 when choosing the configuration, i. e.
4507 make TQM823L_defconfig
4508 - will configure for a plain TQM823L, i. e. no LCD support
4510 make TQM823L_LCD_defconfig
4511 - will configure for a TQM823L with U-Boot console on LCD
4516 Finally, type "make all", and you should get some working U-Boot
4517 images ready for download to / installation on your system:
4519 - "u-boot.bin" is a raw binary image
4520 - "u-boot" is an image in ELF binary format
4521 - "u-boot.srec" is in Motorola S-Record format
4523 By default the build is performed locally and the objects are saved
4524 in the source directory. One of the two methods can be used to change
4525 this behavior and build U-Boot to some external directory:
4527 1. Add O= to the make command line invocations:
4529 make O=/tmp/build distclean
4530 make O=/tmp/build NAME_defconfig
4531 make O=/tmp/build all
4533 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4535 export KBUILD_OUTPUT=/tmp/build
4540 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4544 Please be aware that the Makefiles assume you are using GNU make, so
4545 for instance on NetBSD you might need to use "gmake" instead of
4549 If the system board that you have is not listed, then you will need
4550 to port U-Boot to your hardware platform. To do this, follow these
4553 1. Create a new directory to hold your board specific code. Add any
4554 files you need. In your board directory, you will need at least
4555 the "Makefile" and a "<board>.c".
4556 2. Create a new configuration file "include/configs/<board>.h" for
4558 3. If you're porting U-Boot to a new CPU, then also create a new
4559 directory to hold your CPU specific code. Add any files you need.
4560 4. Run "make <board>_defconfig" with your new name.
4561 5. Type "make", and you should get a working "u-boot.srec" file
4562 to be installed on your target system.
4563 6. Debug and solve any problems that might arise.
4564 [Of course, this last step is much harder than it sounds.]
4567 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4568 ==============================================================
4570 If you have modified U-Boot sources (for instance added a new board
4571 or support for new devices, a new CPU, etc.) you are expected to
4572 provide feedback to the other developers. The feedback normally takes
4573 the form of a "patch", i. e. a context diff against a certain (latest
4574 official or latest in the git repository) version of U-Boot sources.
4576 But before you submit such a patch, please verify that your modifi-
4577 cation did not break existing code. At least make sure that *ALL* of
4578 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4579 just run the buildman script (tools/buildman/buildman), which will
4580 configure and build U-Boot for ALL supported system. Be warned, this
4581 will take a while. Please see the buildman README, or run 'buildman -H'
4585 See also "U-Boot Porting Guide" below.
4588 Monitor Commands - Overview:
4589 ============================
4591 go - start application at address 'addr'
4592 run - run commands in an environment variable
4593 bootm - boot application image from memory
4594 bootp - boot image via network using BootP/TFTP protocol
4595 bootz - boot zImage from memory
4596 tftpboot- boot image via network using TFTP protocol
4597 and env variables "ipaddr" and "serverip"
4598 (and eventually "gatewayip")
4599 tftpput - upload a file via network using TFTP protocol
4600 rarpboot- boot image via network using RARP/TFTP protocol
4601 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4602 loads - load S-Record file over serial line
4603 loadb - load binary file over serial line (kermit mode)
4605 mm - memory modify (auto-incrementing)
4606 nm - memory modify (constant address)
4607 mw - memory write (fill)
4609 cmp - memory compare
4610 crc32 - checksum calculation
4611 i2c - I2C sub-system
4612 sspi - SPI utility commands
4613 base - print or set address offset
4614 printenv- print environment variables
4615 setenv - set environment variables
4616 saveenv - save environment variables to persistent storage
4617 protect - enable or disable FLASH write protection
4618 erase - erase FLASH memory
4619 flinfo - print FLASH memory information
4620 nand - NAND memory operations (see doc/README.nand)
4621 bdinfo - print Board Info structure
4622 iminfo - print header information for application image
4623 coninfo - print console devices and informations
4624 ide - IDE sub-system
4625 loop - infinite loop on address range
4626 loopw - infinite write loop on address range
4627 mtest - simple RAM test
4628 icache - enable or disable instruction cache
4629 dcache - enable or disable data cache
4630 reset - Perform RESET of the CPU
4631 echo - echo args to console
4632 version - print monitor version
4633 help - print online help
4634 ? - alias for 'help'
4637 Monitor Commands - Detailed Description:
4638 ========================================
4642 For now: just type "help <command>".
4645 Environment Variables:
4646 ======================
4648 U-Boot supports user configuration using Environment Variables which
4649 can be made persistent by saving to Flash memory.
4651 Environment Variables are set using "setenv", printed using
4652 "printenv", and saved to Flash using "saveenv". Using "setenv"
4653 without a value can be used to delete a variable from the
4654 environment. As long as you don't save the environment you are
4655 working with an in-memory copy. In case the Flash area containing the
4656 environment is erased by accident, a default environment is provided.
4658 Some configuration options can be set using Environment Variables.
4660 List of environment variables (most likely not complete):
4662 baudrate - see CONFIG_BAUDRATE
4664 bootdelay - see CONFIG_BOOTDELAY
4666 bootcmd - see CONFIG_BOOTCOMMAND
4668 bootargs - Boot arguments when booting an RTOS image
4670 bootfile - Name of the image to load with TFTP
4672 bootm_low - Memory range available for image processing in the bootm
4673 command can be restricted. This variable is given as
4674 a hexadecimal number and defines lowest address allowed
4675 for use by the bootm command. See also "bootm_size"
4676 environment variable. Address defined by "bootm_low" is
4677 also the base of the initial memory mapping for the Linux
4678 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4681 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4682 This variable is given as a hexadecimal number and it
4683 defines the size of the memory region starting at base
4684 address bootm_low that is accessible by the Linux kernel
4685 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4686 as the default value if it is defined, and bootm_size is
4689 bootm_size - Memory range available for image processing in the bootm
4690 command can be restricted. This variable is given as
4691 a hexadecimal number and defines the size of the region
4692 allowed for use by the bootm command. See also "bootm_low"
4693 environment variable.
4695 updatefile - Location of the software update file on a TFTP server, used
4696 by the automatic software update feature. Please refer to
4697 documentation in doc/README.update for more details.
4699 autoload - if set to "no" (any string beginning with 'n'),
4700 "bootp" will just load perform a lookup of the
4701 configuration from the BOOTP server, but not try to
4702 load any image using TFTP
4704 autostart - if set to "yes", an image loaded using the "bootp",
4705 "rarpboot", "tftpboot" or "diskboot" commands will
4706 be automatically started (by internally calling
4709 If set to "no", a standalone image passed to the
4710 "bootm" command will be copied to the load address
4711 (and eventually uncompressed), but NOT be started.
4712 This can be used to load and uncompress arbitrary
4715 fdt_high - if set this restricts the maximum address that the
4716 flattened device tree will be copied into upon boot.
4717 For example, if you have a system with 1 GB memory
4718 at physical address 0x10000000, while Linux kernel
4719 only recognizes the first 704 MB as low memory, you
4720 may need to set fdt_high as 0x3C000000 to have the
4721 device tree blob be copied to the maximum address
4722 of the 704 MB low memory, so that Linux kernel can
4723 access it during the boot procedure.
4725 If this is set to the special value 0xFFFFFFFF then
4726 the fdt will not be copied at all on boot. For this
4727 to work it must reside in writable memory, have
4728 sufficient padding on the end of it for u-boot to
4729 add the information it needs into it, and the memory
4730 must be accessible by the kernel.
4732 fdtcontroladdr- if set this is the address of the control flattened
4733 device tree used by U-Boot when CONFIG_OF_CONTROL is
4736 i2cfast - (PPC405GP|PPC405EP only)
4737 if set to 'y' configures Linux I2C driver for fast
4738 mode (400kHZ). This environment variable is used in
4739 initialization code. So, for changes to be effective
4740 it must be saved and board must be reset.
4742 initrd_high - restrict positioning of initrd images:
4743 If this variable is not set, initrd images will be
4744 copied to the highest possible address in RAM; this
4745 is usually what you want since it allows for
4746 maximum initrd size. If for some reason you want to
4747 make sure that the initrd image is loaded below the
4748 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4749 variable to a value of "no" or "off" or "0".
4750 Alternatively, you can set it to a maximum upper
4751 address to use (U-Boot will still check that it
4752 does not overwrite the U-Boot stack and data).
4754 For instance, when you have a system with 16 MB
4755 RAM, and want to reserve 4 MB from use by Linux,
4756 you can do this by adding "mem=12M" to the value of
4757 the "bootargs" variable. However, now you must make
4758 sure that the initrd image is placed in the first
4759 12 MB as well - this can be done with
4761 setenv initrd_high 00c00000
4763 If you set initrd_high to 0xFFFFFFFF, this is an
4764 indication to U-Boot that all addresses are legal
4765 for the Linux kernel, including addresses in flash
4766 memory. In this case U-Boot will NOT COPY the
4767 ramdisk at all. This may be useful to reduce the
4768 boot time on your system, but requires that this
4769 feature is supported by your Linux kernel.
4771 ipaddr - IP address; needed for tftpboot command
4773 loadaddr - Default load address for commands like "bootp",
4774 "rarpboot", "tftpboot", "loadb" or "diskboot"
4776 loads_echo - see CONFIG_LOADS_ECHO
4778 serverip - TFTP server IP address; needed for tftpboot command
4780 bootretry - see CONFIG_BOOT_RETRY_TIME
4782 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4784 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4786 ethprime - controls which interface is used first.
4788 ethact - controls which interface is currently active.
4789 For example you can do the following
4791 => setenv ethact FEC
4792 => ping 192.168.0.1 # traffic sent on FEC
4793 => setenv ethact SCC
4794 => ping 10.0.0.1 # traffic sent on SCC
4796 ethrotate - When set to "no" U-Boot does not go through all
4797 available network interfaces.
4798 It just stays at the currently selected interface.
4800 netretry - When set to "no" each network operation will
4801 either succeed or fail without retrying.
4802 When set to "once" the network operation will
4803 fail when all the available network interfaces
4804 are tried once without success.
4805 Useful on scripts which control the retry operation
4808 npe_ucode - set load address for the NPE microcode
4810 silent_linux - If set then Linux will be told to boot silently, by
4811 changing the console to be empty. If "yes" it will be
4812 made silent. If "no" it will not be made silent. If
4813 unset, then it will be made silent if the U-Boot console
4816 tftpsrcp - If this is set, the value is used for TFTP's
4819 tftpdstp - If this is set, the value is used for TFTP's UDP
4820 destination port instead of the Well Know Port 69.
4822 tftpblocksize - Block size to use for TFTP transfers; if not set,
4823 we use the TFTP server's default block size
4825 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4826 seconds, minimum value is 1000 = 1 second). Defines
4827 when a packet is considered to be lost so it has to
4828 be retransmitted. The default is 5000 = 5 seconds.
4829 Lowering this value may make downloads succeed
4830 faster in networks with high packet loss rates or
4831 with unreliable TFTP servers.
4833 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4834 unit, minimum value = 0). Defines how many timeouts
4835 can happen during a single file transfer before that
4836 transfer is aborted. The default is 10, and 0 means
4837 'no timeouts allowed'. Increasing this value may help
4838 downloads succeed with high packet loss rates, or with
4839 unreliable TFTP servers or client hardware.
4841 vlan - When set to a value < 4095 the traffic over
4842 Ethernet is encapsulated/received over 802.1q
4845 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4846 Unsigned value, in milliseconds. If not set, the period will
4847 be either the default (28000), or a value based on
4848 CONFIG_NET_RETRY_COUNT, if defined. This value has
4849 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4851 The following image location variables contain the location of images
4852 used in booting. The "Image" column gives the role of the image and is
4853 not an environment variable name. The other columns are environment
4854 variable names. "File Name" gives the name of the file on a TFTP
4855 server, "RAM Address" gives the location in RAM the image will be
4856 loaded to, and "Flash Location" gives the image's address in NOR
4857 flash or offset in NAND flash.
4859 *Note* - these variables don't have to be defined for all boards, some
4860 boards currently use other variables for these purposes, and some
4861 boards use these variables for other purposes.
4863 Image File Name RAM Address Flash Location
4864 ----- --------- ----------- --------------
4865 u-boot u-boot u-boot_addr_r u-boot_addr
4866 Linux kernel bootfile kernel_addr_r kernel_addr
4867 device tree blob fdtfile fdt_addr_r fdt_addr
4868 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4870 The following environment variables may be used and automatically
4871 updated by the network boot commands ("bootp" and "rarpboot"),
4872 depending the information provided by your boot server:
4874 bootfile - see above
4875 dnsip - IP address of your Domain Name Server
4876 dnsip2 - IP address of your secondary Domain Name Server
4877 gatewayip - IP address of the Gateway (Router) to use
4878 hostname - Target hostname
4880 netmask - Subnet Mask
4881 rootpath - Pathname of the root filesystem on the NFS server
4882 serverip - see above
4885 There are two special Environment Variables:
4887 serial# - contains hardware identification information such
4888 as type string and/or serial number
4889 ethaddr - Ethernet address
4891 These variables can be set only once (usually during manufacturing of
4892 the board). U-Boot refuses to delete or overwrite these variables
4893 once they have been set once.
4896 Further special Environment Variables:
4898 ver - Contains the U-Boot version string as printed
4899 with the "version" command. This variable is
4900 readonly (see CONFIG_VERSION_VARIABLE).
4903 Please note that changes to some configuration parameters may take
4904 only effect after the next boot (yes, that's just like Windoze :-).
4907 Callback functions for environment variables:
4908 ---------------------------------------------
4910 For some environment variables, the behavior of u-boot needs to change
4911 when their values are changed. This functionality allows functions to
4912 be associated with arbitrary variables. On creation, overwrite, or
4913 deletion, the callback will provide the opportunity for some side
4914 effect to happen or for the change to be rejected.
4916 The callbacks are named and associated with a function using the
4917 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4919 These callbacks are associated with variables in one of two ways. The
4920 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4921 in the board configuration to a string that defines a list of
4922 associations. The list must be in the following format:
4924 entry = variable_name[:callback_name]
4927 If the callback name is not specified, then the callback is deleted.
4928 Spaces are also allowed anywhere in the list.
4930 Callbacks can also be associated by defining the ".callbacks" variable
4931 with the same list format above. Any association in ".callbacks" will
4932 override any association in the static list. You can define
4933 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4934 ".callbacks" environment variable in the default or embedded environment.
4936 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4937 regular expression. This allows multiple variables to be connected to
4938 the same callback without explicitly listing them all out.
4941 Command Line Parsing:
4942 =====================
4944 There are two different command line parsers available with U-Boot:
4945 the old "simple" one, and the much more powerful "hush" shell:
4947 Old, simple command line parser:
4948 --------------------------------
4950 - supports environment variables (through setenv / saveenv commands)
4951 - several commands on one line, separated by ';'
4952 - variable substitution using "... ${name} ..." syntax
4953 - special characters ('$', ';') can be escaped by prefixing with '\',
4955 setenv bootcmd bootm \${address}
4956 - You can also escape text by enclosing in single apostrophes, for example:
4957 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4962 - similar to Bourne shell, with control structures like
4963 if...then...else...fi, for...do...done; while...do...done,
4964 until...do...done, ...
4965 - supports environment ("global") variables (through setenv / saveenv
4966 commands) and local shell variables (through standard shell syntax
4967 "name=value"); only environment variables can be used with "run"
4973 (1) If a command line (or an environment variable executed by a "run"
4974 command) contains several commands separated by semicolon, and
4975 one of these commands fails, then the remaining commands will be
4978 (2) If you execute several variables with one call to run (i. e.
4979 calling run with a list of variables as arguments), any failing
4980 command will cause "run" to terminate, i. e. the remaining
4981 variables are not executed.
4983 Note for Redundant Ethernet Interfaces:
4984 =======================================
4986 Some boards come with redundant Ethernet interfaces; U-Boot supports
4987 such configurations and is capable of automatic selection of a
4988 "working" interface when needed. MAC assignment works as follows:
4990 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4991 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4992 "eth1addr" (=>eth1), "eth2addr", ...
4994 If the network interface stores some valid MAC address (for instance
4995 in SROM), this is used as default address if there is NO correspon-
4996 ding setting in the environment; if the corresponding environment
4997 variable is set, this overrides the settings in the card; that means:
4999 o If the SROM has a valid MAC address, and there is no address in the
5000 environment, the SROM's address is used.
5002 o If there is no valid address in the SROM, and a definition in the
5003 environment exists, then the value from the environment variable is
5006 o If both the SROM and the environment contain a MAC address, and
5007 both addresses are the same, this MAC address is used.
5009 o If both the SROM and the environment contain a MAC address, and the
5010 addresses differ, the value from the environment is used and a
5013 o If neither SROM nor the environment contain a MAC address, an error
5014 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5015 a random, locally-assigned MAC is used.
5017 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5018 will be programmed into hardware as part of the initialization process. This
5019 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5020 The naming convention is as follows:
5021 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5026 U-Boot is capable of booting (and performing other auxiliary operations on)
5027 images in two formats:
5029 New uImage format (FIT)
5030 -----------------------
5032 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5033 to Flattened Device Tree). It allows the use of images with multiple
5034 components (several kernels, ramdisks, etc.), with contents protected by
5035 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5041 Old image format is based on binary files which can be basically anything,
5042 preceded by a special header; see the definitions in include/image.h for
5043 details; basically, the header defines the following image properties:
5045 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5046 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5047 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5048 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5050 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5051 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5052 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5053 * Compression Type (uncompressed, gzip, bzip2)
5059 The header is marked by a special Magic Number, and both the header
5060 and the data portions of the image are secured against corruption by
5067 Although U-Boot should support any OS or standalone application
5068 easily, the main focus has always been on Linux during the design of
5071 U-Boot includes many features that so far have been part of some
5072 special "boot loader" code within the Linux kernel. Also, any
5073 "initrd" images to be used are no longer part of one big Linux image;
5074 instead, kernel and "initrd" are separate images. This implementation
5075 serves several purposes:
5077 - the same features can be used for other OS or standalone
5078 applications (for instance: using compressed images to reduce the
5079 Flash memory footprint)
5081 - it becomes much easier to port new Linux kernel versions because
5082 lots of low-level, hardware dependent stuff are done by U-Boot
5084 - the same Linux kernel image can now be used with different "initrd"
5085 images; of course this also means that different kernel images can
5086 be run with the same "initrd". This makes testing easier (you don't
5087 have to build a new "zImage.initrd" Linux image when you just
5088 change a file in your "initrd"). Also, a field-upgrade of the
5089 software is easier now.
5095 Porting Linux to U-Boot based systems:
5096 ---------------------------------------
5098 U-Boot cannot save you from doing all the necessary modifications to
5099 configure the Linux device drivers for use with your target hardware
5100 (no, we don't intend to provide a full virtual machine interface to
5103 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5105 Just make sure your machine specific header file (for instance
5106 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5107 Information structure as we define in include/asm-<arch>/u-boot.h,
5108 and make sure that your definition of IMAP_ADDR uses the same value
5109 as your U-Boot configuration in CONFIG_SYS_IMMR.
5111 Note that U-Boot now has a driver model, a unified model for drivers.
5112 If you are adding a new driver, plumb it into driver model. If there
5113 is no uclass available, you are encouraged to create one. See
5117 Configuring the Linux kernel:
5118 -----------------------------
5120 No specific requirements for U-Boot. Make sure you have some root
5121 device (initial ramdisk, NFS) for your target system.
5124 Building a Linux Image:
5125 -----------------------
5127 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5128 not used. If you use recent kernel source, a new build target
5129 "uImage" will exist which automatically builds an image usable by
5130 U-Boot. Most older kernels also have support for a "pImage" target,
5131 which was introduced for our predecessor project PPCBoot and uses a
5132 100% compatible format.
5136 make TQM850L_defconfig
5141 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5142 encapsulate a compressed Linux kernel image with header information,
5143 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5145 * build a standard "vmlinux" kernel image (in ELF binary format):
5147 * convert the kernel into a raw binary image:
5149 ${CROSS_COMPILE}-objcopy -O binary \
5150 -R .note -R .comment \
5151 -S vmlinux linux.bin
5153 * compress the binary image:
5157 * package compressed binary image for U-Boot:
5159 mkimage -A ppc -O linux -T kernel -C gzip \
5160 -a 0 -e 0 -n "Linux Kernel Image" \
5161 -d linux.bin.gz uImage
5164 The "mkimage" tool can also be used to create ramdisk images for use
5165 with U-Boot, either separated from the Linux kernel image, or
5166 combined into one file. "mkimage" encapsulates the images with a 64
5167 byte header containing information about target architecture,
5168 operating system, image type, compression method, entry points, time
5169 stamp, CRC32 checksums, etc.
5171 "mkimage" can be called in two ways: to verify existing images and
5172 print the header information, or to build new images.
5174 In the first form (with "-l" option) mkimage lists the information
5175 contained in the header of an existing U-Boot image; this includes
5176 checksum verification:
5178 tools/mkimage -l image
5179 -l ==> list image header information
5181 The second form (with "-d" option) is used to build a U-Boot image
5182 from a "data file" which is used as image payload:
5184 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5185 -n name -d data_file image
5186 -A ==> set architecture to 'arch'
5187 -O ==> set operating system to 'os'
5188 -T ==> set image type to 'type'
5189 -C ==> set compression type 'comp'
5190 -a ==> set load address to 'addr' (hex)
5191 -e ==> set entry point to 'ep' (hex)
5192 -n ==> set image name to 'name'
5193 -d ==> use image data from 'datafile'
5195 Right now, all Linux kernels for PowerPC systems use the same load
5196 address (0x00000000), but the entry point address depends on the
5199 - 2.2.x kernels have the entry point at 0x0000000C,
5200 - 2.3.x and later kernels have the entry point at 0x00000000.
5202 So a typical call to build a U-Boot image would read:
5204 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5205 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5206 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5207 > examples/uImage.TQM850L
5208 Image Name: 2.4.4 kernel for TQM850L
5209 Created: Wed Jul 19 02:34:59 2000
5210 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5211 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5212 Load Address: 0x00000000
5213 Entry Point: 0x00000000
5215 To verify the contents of the image (or check for corruption):
5217 -> tools/mkimage -l examples/uImage.TQM850L
5218 Image Name: 2.4.4 kernel for TQM850L
5219 Created: Wed Jul 19 02:34:59 2000
5220 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5221 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5222 Load Address: 0x00000000
5223 Entry Point: 0x00000000
5225 NOTE: for embedded systems where boot time is critical you can trade
5226 speed for memory and install an UNCOMPRESSED image instead: this
5227 needs more space in Flash, but boots much faster since it does not
5228 need to be uncompressed:
5230 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5231 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5232 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5233 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5234 > examples/uImage.TQM850L-uncompressed
5235 Image Name: 2.4.4 kernel for TQM850L
5236 Created: Wed Jul 19 02:34:59 2000
5237 Image Type: PowerPC Linux Kernel Image (uncompressed)
5238 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5239 Load Address: 0x00000000
5240 Entry Point: 0x00000000
5243 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5244 when your kernel is intended to use an initial ramdisk:
5246 -> tools/mkimage -n 'Simple Ramdisk Image' \
5247 > -A ppc -O linux -T ramdisk -C gzip \
5248 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5249 Image Name: Simple Ramdisk Image
5250 Created: Wed Jan 12 14:01:50 2000
5251 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5252 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5253 Load Address: 0x00000000
5254 Entry Point: 0x00000000
5256 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5257 option performs the converse operation of the mkimage's second form (the "-d"
5258 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5261 tools/dumpimage -i image -T type -p position data_file
5262 -i ==> extract from the 'image' a specific 'data_file'
5263 -T ==> set image type to 'type'
5264 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5267 Installing a Linux Image:
5268 -------------------------
5270 To downloading a U-Boot image over the serial (console) interface,
5271 you must convert the image to S-Record format:
5273 objcopy -I binary -O srec examples/image examples/image.srec
5275 The 'objcopy' does not understand the information in the U-Boot
5276 image header, so the resulting S-Record file will be relative to
5277 address 0x00000000. To load it to a given address, you need to
5278 specify the target address as 'offset' parameter with the 'loads'
5281 Example: install the image to address 0x40100000 (which on the
5282 TQM8xxL is in the first Flash bank):
5284 => erase 40100000 401FFFFF
5290 ## Ready for S-Record download ...
5291 ~>examples/image.srec
5292 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5294 15989 15990 15991 15992
5295 [file transfer complete]
5297 ## Start Addr = 0x00000000
5300 You can check the success of the download using the 'iminfo' command;
5301 this includes a checksum verification so you can be sure no data
5302 corruption happened:
5306 ## Checking Image at 40100000 ...
5307 Image Name: 2.2.13 for initrd on TQM850L
5308 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5309 Data Size: 335725 Bytes = 327 kB = 0 MB
5310 Load Address: 00000000
5311 Entry Point: 0000000c
5312 Verifying Checksum ... OK
5318 The "bootm" command is used to boot an application that is stored in
5319 memory (RAM or Flash). In case of a Linux kernel image, the contents
5320 of the "bootargs" environment variable is passed to the kernel as
5321 parameters. You can check and modify this variable using the
5322 "printenv" and "setenv" commands:
5325 => printenv bootargs
5326 bootargs=root=/dev/ram
5328 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5330 => printenv bootargs
5331 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5334 ## Booting Linux kernel at 40020000 ...
5335 Image Name: 2.2.13 for NFS on TQM850L
5336 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5337 Data Size: 381681 Bytes = 372 kB = 0 MB
5338 Load Address: 00000000
5339 Entry Point: 0000000c
5340 Verifying Checksum ... OK
5341 Uncompressing Kernel Image ... OK
5342 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
5343 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5344 time_init: decrementer frequency = 187500000/60
5345 Calibrating delay loop... 49.77 BogoMIPS
5346 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5349 If you want to boot a Linux kernel with initial RAM disk, you pass
5350 the memory addresses of both the kernel and the initrd image (PPBCOOT
5351 format!) to the "bootm" command:
5353 => imi 40100000 40200000
5355 ## Checking Image at 40100000 ...
5356 Image Name: 2.2.13 for initrd on TQM850L
5357 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5358 Data Size: 335725 Bytes = 327 kB = 0 MB
5359 Load Address: 00000000
5360 Entry Point: 0000000c
5361 Verifying Checksum ... OK
5363 ## Checking Image at 40200000 ...
5364 Image Name: Simple Ramdisk Image
5365 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5366 Data Size: 566530 Bytes = 553 kB = 0 MB
5367 Load Address: 00000000
5368 Entry Point: 00000000
5369 Verifying Checksum ... OK
5371 => bootm 40100000 40200000
5372 ## Booting Linux kernel at 40100000 ...
5373 Image Name: 2.2.13 for initrd on TQM850L
5374 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5375 Data Size: 335725 Bytes = 327 kB = 0 MB
5376 Load Address: 00000000
5377 Entry Point: 0000000c
5378 Verifying Checksum ... OK
5379 Uncompressing Kernel Image ... OK
5380 ## Loading RAMDisk Image at 40200000 ...
5381 Image Name: Simple Ramdisk Image
5382 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5383 Data Size: 566530 Bytes = 553 kB = 0 MB
5384 Load Address: 00000000
5385 Entry Point: 00000000
5386 Verifying Checksum ... OK
5387 Loading Ramdisk ... OK
5388 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
5389 Boot arguments: root=/dev/ram
5390 time_init: decrementer frequency = 187500000/60
5391 Calibrating delay loop... 49.77 BogoMIPS
5393 RAMDISK: Compressed image found at block 0
5394 VFS: Mounted root (ext2 filesystem).
5398 Boot Linux and pass a flat device tree:
5401 First, U-Boot must be compiled with the appropriate defines. See the section
5402 titled "Linux Kernel Interface" above for a more in depth explanation. The
5403 following is an example of how to start a kernel and pass an updated
5409 oft=oftrees/mpc8540ads.dtb
5410 => tftp $oftaddr $oft
5411 Speed: 1000, full duplex
5413 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5414 Filename 'oftrees/mpc8540ads.dtb'.
5415 Load address: 0x300000
5418 Bytes transferred = 4106 (100a hex)
5419 => tftp $loadaddr $bootfile
5420 Speed: 1000, full duplex
5422 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5424 Load address: 0x200000
5425 Loading:############
5427 Bytes transferred = 1029407 (fb51f hex)
5432 => bootm $loadaddr - $oftaddr
5433 ## Booting image at 00200000 ...
5434 Image Name: Linux-2.6.17-dirty
5435 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5436 Data Size: 1029343 Bytes = 1005.2 kB
5437 Load Address: 00000000
5438 Entry Point: 00000000
5439 Verifying Checksum ... OK
5440 Uncompressing Kernel Image ... OK
5441 Booting using flat device tree at 0x300000
5442 Using MPC85xx ADS machine description
5443 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5447 More About U-Boot Image Types:
5448 ------------------------------
5450 U-Boot supports the following image types:
5452 "Standalone Programs" are directly runnable in the environment
5453 provided by U-Boot; it is expected that (if they behave
5454 well) you can continue to work in U-Boot after return from
5455 the Standalone Program.
5456 "OS Kernel Images" are usually images of some Embedded OS which
5457 will take over control completely. Usually these programs
5458 will install their own set of exception handlers, device
5459 drivers, set up the MMU, etc. - this means, that you cannot
5460 expect to re-enter U-Boot except by resetting the CPU.
5461 "RAMDisk Images" are more or less just data blocks, and their
5462 parameters (address, size) are passed to an OS kernel that is
5464 "Multi-File Images" contain several images, typically an OS
5465 (Linux) kernel image and one or more data images like
5466 RAMDisks. This construct is useful for instance when you want
5467 to boot over the network using BOOTP etc., where the boot
5468 server provides just a single image file, but you want to get
5469 for instance an OS kernel and a RAMDisk image.
5471 "Multi-File Images" start with a list of image sizes, each
5472 image size (in bytes) specified by an "uint32_t" in network
5473 byte order. This list is terminated by an "(uint32_t)0".
5474 Immediately after the terminating 0 follow the images, one by
5475 one, all aligned on "uint32_t" boundaries (size rounded up to
5476 a multiple of 4 bytes).
5478 "Firmware Images" are binary images containing firmware (like
5479 U-Boot or FPGA images) which usually will be programmed to
5482 "Script files" are command sequences that will be executed by
5483 U-Boot's command interpreter; this feature is especially
5484 useful when you configure U-Boot to use a real shell (hush)
5485 as command interpreter.
5487 Booting the Linux zImage:
5488 -------------------------
5490 On some platforms, it's possible to boot Linux zImage. This is done
5491 using the "bootz" command. The syntax of "bootz" command is the same
5492 as the syntax of "bootm" command.
5494 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5495 kernel with raw initrd images. The syntax is slightly different, the
5496 address of the initrd must be augmented by it's size, in the following
5497 format: "<initrd addres>:<initrd size>".
5503 One of the features of U-Boot is that you can dynamically load and
5504 run "standalone" applications, which can use some resources of
5505 U-Boot like console I/O functions or interrupt services.
5507 Two simple examples are included with the sources:
5512 'examples/hello_world.c' contains a small "Hello World" Demo
5513 application; it is automatically compiled when you build U-Boot.
5514 It's configured to run at address 0x00040004, so you can play with it
5518 ## Ready for S-Record download ...
5519 ~>examples/hello_world.srec
5520 1 2 3 4 5 6 7 8 9 10 11 ...
5521 [file transfer complete]
5523 ## Start Addr = 0x00040004
5525 => go 40004 Hello World! This is a test.
5526 ## Starting application at 0x00040004 ...
5537 Hit any key to exit ...
5539 ## Application terminated, rc = 0x0
5541 Another example, which demonstrates how to register a CPM interrupt
5542 handler with the U-Boot code, can be found in 'examples/timer.c'.
5543 Here, a CPM timer is set up to generate an interrupt every second.
5544 The interrupt service routine is trivial, just printing a '.'
5545 character, but this is just a demo program. The application can be
5546 controlled by the following keys:
5548 ? - print current values og the CPM Timer registers
5549 b - enable interrupts and start timer
5550 e - stop timer and disable interrupts
5551 q - quit application
5554 ## Ready for S-Record download ...
5555 ~>examples/timer.srec
5556 1 2 3 4 5 6 7 8 9 10 11 ...
5557 [file transfer complete]
5559 ## Start Addr = 0x00040004
5562 ## Starting application at 0x00040004 ...
5565 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5568 [q, b, e, ?] Set interval 1000000 us
5571 [q, b, e, ?] ........
5572 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5575 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5578 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5581 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5583 [q, b, e, ?] ...Stopping timer
5585 [q, b, e, ?] ## Application terminated, rc = 0x0
5591 Over time, many people have reported problems when trying to use the
5592 "minicom" terminal emulation program for serial download. I (wd)
5593 consider minicom to be broken, and recommend not to use it. Under
5594 Unix, I recommend to use C-Kermit for general purpose use (and
5595 especially for kermit binary protocol download ("loadb" command), and
5596 use "cu" for S-Record download ("loads" command). See
5597 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5598 for help with kermit.
5601 Nevertheless, if you absolutely want to use it try adding this
5602 configuration to your "File transfer protocols" section:
5604 Name Program Name U/D FullScr IO-Red. Multi
5605 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5606 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5612 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5613 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5615 Building requires a cross environment; it is known to work on
5616 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5617 need gmake since the Makefiles are not compatible with BSD make).
5618 Note that the cross-powerpc package does not install include files;
5619 attempting to build U-Boot will fail because <machine/ansi.h> is
5620 missing. This file has to be installed and patched manually:
5622 # cd /usr/pkg/cross/powerpc-netbsd/include
5624 # ln -s powerpc machine
5625 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5626 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5628 Native builds *don't* work due to incompatibilities between native
5629 and U-Boot include files.
5631 Booting assumes that (the first part of) the image booted is a
5632 stage-2 loader which in turn loads and then invokes the kernel
5633 proper. Loader sources will eventually appear in the NetBSD source
5634 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5635 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5638 Implementation Internals:
5639 =========================
5641 The following is not intended to be a complete description of every
5642 implementation detail. However, it should help to understand the
5643 inner workings of U-Boot and make it easier to port it to custom
5647 Initial Stack, Global Data:
5648 ---------------------------
5650 The implementation of U-Boot is complicated by the fact that U-Boot
5651 starts running out of ROM (flash memory), usually without access to
5652 system RAM (because the memory controller is not initialized yet).
5653 This means that we don't have writable Data or BSS segments, and BSS
5654 is not initialized as zero. To be able to get a C environment working
5655 at all, we have to allocate at least a minimal stack. Implementation
5656 options for this are defined and restricted by the CPU used: Some CPU
5657 models provide on-chip memory (like the IMMR area on MPC8xx and
5658 MPC826x processors), on others (parts of) the data cache can be
5659 locked as (mis-) used as memory, etc.
5661 Chris Hallinan posted a good summary of these issues to the
5662 U-Boot mailing list:
5664 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5665 From: "Chris Hallinan" <clh@net1plus.com>
5666 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5669 Correct me if I'm wrong, folks, but the way I understand it
5670 is this: Using DCACHE as initial RAM for Stack, etc, does not
5671 require any physical RAM backing up the cache. The cleverness
5672 is that the cache is being used as a temporary supply of
5673 necessary storage before the SDRAM controller is setup. It's
5674 beyond the scope of this list to explain the details, but you
5675 can see how this works by studying the cache architecture and
5676 operation in the architecture and processor-specific manuals.
5678 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5679 is another option for the system designer to use as an
5680 initial stack/RAM area prior to SDRAM being available. Either
5681 option should work for you. Using CS 4 should be fine if your
5682 board designers haven't used it for something that would
5683 cause you grief during the initial boot! It is frequently not
5686 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5687 with your processor/board/system design. The default value
5688 you will find in any recent u-boot distribution in
5689 walnut.h should work for you. I'd set it to a value larger
5690 than your SDRAM module. If you have a 64MB SDRAM module, set
5691 it above 400_0000. Just make sure your board has no resources
5692 that are supposed to respond to that address! That code in
5693 start.S has been around a while and should work as is when
5694 you get the config right.
5699 It is essential to remember this, since it has some impact on the C
5700 code for the initialization procedures:
5702 * Initialized global data (data segment) is read-only. Do not attempt
5705 * Do not use any uninitialized global data (or implicitly initialized
5706 as zero data - BSS segment) at all - this is undefined, initiali-
5707 zation is performed later (when relocating to RAM).
5709 * Stack space is very limited. Avoid big data buffers or things like
5712 Having only the stack as writable memory limits means we cannot use
5713 normal global data to share information between the code. But it
5714 turned out that the implementation of U-Boot can be greatly
5715 simplified by making a global data structure (gd_t) available to all
5716 functions. We could pass a pointer to this data as argument to _all_
5717 functions, but this would bloat the code. Instead we use a feature of
5718 the GCC compiler (Global Register Variables) to share the data: we
5719 place a pointer (gd) to the global data into a register which we
5720 reserve for this purpose.
5722 When choosing a register for such a purpose we are restricted by the
5723 relevant (E)ABI specifications for the current architecture, and by
5724 GCC's implementation.
5726 For PowerPC, the following registers have specific use:
5728 R2: reserved for system use
5729 R3-R4: parameter passing and return values
5730 R5-R10: parameter passing
5731 R13: small data area pointer
5735 (U-Boot also uses R12 as internal GOT pointer. r12
5736 is a volatile register so r12 needs to be reset when
5737 going back and forth between asm and C)
5739 ==> U-Boot will use R2 to hold a pointer to the global data
5741 Note: on PPC, we could use a static initializer (since the
5742 address of the global data structure is known at compile time),
5743 but it turned out that reserving a register results in somewhat
5744 smaller code - although the code savings are not that big (on
5745 average for all boards 752 bytes for the whole U-Boot image,
5746 624 text + 127 data).
5748 On ARM, the following registers are used:
5750 R0: function argument word/integer result
5751 R1-R3: function argument word
5752 R9: platform specific
5753 R10: stack limit (used only if stack checking is enabled)
5754 R11: argument (frame) pointer
5755 R12: temporary workspace
5758 R15: program counter
5760 ==> U-Boot will use R9 to hold a pointer to the global data
5762 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5764 On Nios II, the ABI is documented here:
5765 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5767 ==> U-Boot will use gp to hold a pointer to the global data
5769 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5770 to access small data sections, so gp is free.
5772 On NDS32, the following registers are used:
5774 R0-R1: argument/return
5776 R15: temporary register for assembler
5777 R16: trampoline register
5778 R28: frame pointer (FP)
5779 R29: global pointer (GP)
5780 R30: link register (LP)
5781 R31: stack pointer (SP)
5782 PC: program counter (PC)
5784 ==> U-Boot will use R10 to hold a pointer to the global data
5786 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5787 or current versions of GCC may "optimize" the code too much.
5792 U-Boot runs in system state and uses physical addresses, i.e. the
5793 MMU is not used either for address mapping nor for memory protection.
5795 The available memory is mapped to fixed addresses using the memory
5796 controller. In this process, a contiguous block is formed for each
5797 memory type (Flash, SDRAM, SRAM), even when it consists of several
5798 physical memory banks.
5800 U-Boot is installed in the first 128 kB of the first Flash bank (on
5801 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5802 booting and sizing and initializing DRAM, the code relocates itself
5803 to the upper end of DRAM. Immediately below the U-Boot code some
5804 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5805 configuration setting]. Below that, a structure with global Board
5806 Info data is placed, followed by the stack (growing downward).
5808 Additionally, some exception handler code is copied to the low 8 kB
5809 of DRAM (0x00000000 ... 0x00001FFF).
5811 So a typical memory configuration with 16 MB of DRAM could look like
5814 0x0000 0000 Exception Vector code
5817 0x0000 2000 Free for Application Use
5823 0x00FB FF20 Monitor Stack (Growing downward)
5824 0x00FB FFAC Board Info Data and permanent copy of global data
5825 0x00FC 0000 Malloc Arena
5828 0x00FE 0000 RAM Copy of Monitor Code
5829 ... eventually: LCD or video framebuffer
5830 ... eventually: pRAM (Protected RAM - unchanged by reset)
5831 0x00FF FFFF [End of RAM]
5834 System Initialization:
5835 ----------------------
5837 In the reset configuration, U-Boot starts at the reset entry point
5838 (on most PowerPC systems at address 0x00000100). Because of the reset
5839 configuration for CS0# this is a mirror of the on board Flash memory.
5840 To be able to re-map memory U-Boot then jumps to its link address.
5841 To be able to implement the initialization code in C, a (small!)
5842 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5843 which provide such a feature like MPC8xx or MPC8260), or in a locked
5844 part of the data cache. After that, U-Boot initializes the CPU core,
5845 the caches and the SIU.
5847 Next, all (potentially) available memory banks are mapped using a
5848 preliminary mapping. For example, we put them on 512 MB boundaries
5849 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5850 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5851 programmed for SDRAM access. Using the temporary configuration, a
5852 simple memory test is run that determines the size of the SDRAM
5855 When there is more than one SDRAM bank, and the banks are of
5856 different size, the largest is mapped first. For equal size, the first
5857 bank (CS2#) is mapped first. The first mapping is always for address
5858 0x00000000, with any additional banks following immediately to create
5859 contiguous memory starting from 0.
5861 Then, the monitor installs itself at the upper end of the SDRAM area
5862 and allocates memory for use by malloc() and for the global Board
5863 Info data; also, the exception vector code is copied to the low RAM
5864 pages, and the final stack is set up.
5866 Only after this relocation will you have a "normal" C environment;
5867 until that you are restricted in several ways, mostly because you are
5868 running from ROM, and because the code will have to be relocated to a
5872 U-Boot Porting Guide:
5873 ----------------------
5875 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5879 int main(int argc, char *argv[])
5881 sighandler_t no_more_time;
5883 signal(SIGALRM, no_more_time);
5884 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5886 if (available_money > available_manpower) {
5887 Pay consultant to port U-Boot;
5891 Download latest U-Boot source;
5893 Subscribe to u-boot mailing list;
5896 email("Hi, I am new to U-Boot, how do I get started?");
5899 Read the README file in the top level directory;
5900 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5901 Read applicable doc/*.README;
5902 Read the source, Luke;
5903 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5906 if (available_money > toLocalCurrency ($2500))
5909 Add a lot of aggravation and time;
5911 if (a similar board exists) { /* hopefully... */
5912 cp -a board/<similar> board/<myboard>
5913 cp include/configs/<similar>.h include/configs/<myboard>.h
5915 Create your own board support subdirectory;
5916 Create your own board include/configs/<myboard>.h file;
5918 Edit new board/<myboard> files
5919 Edit new include/configs/<myboard>.h
5924 Add / modify source code;
5928 email("Hi, I am having problems...");
5930 Send patch file to the U-Boot email list;
5931 if (reasonable critiques)
5932 Incorporate improvements from email list code review;
5934 Defend code as written;
5940 void no_more_time (int sig)
5949 All contributions to U-Boot should conform to the Linux kernel
5950 coding style; see the file "Documentation/CodingStyle" and the script
5951 "scripts/Lindent" in your Linux kernel source directory.
5953 Source files originating from a different project (for example the
5954 MTD subsystem) are generally exempt from these guidelines and are not
5955 reformatted to ease subsequent migration to newer versions of those
5958 Please note that U-Boot is implemented in C (and to some small parts in
5959 Assembler); no C++ is used, so please do not use C++ style comments (//)
5962 Please also stick to the following formatting rules:
5963 - remove any trailing white space
5964 - use TAB characters for indentation and vertical alignment, not spaces
5965 - make sure NOT to use DOS '\r\n' line feeds
5966 - do not add more than 2 consecutive empty lines to source files
5967 - do not add trailing empty lines to source files
5969 Submissions which do not conform to the standards may be returned
5970 with a request to reformat the changes.
5976 Since the number of patches for U-Boot is growing, we need to
5977 establish some rules. Submissions which do not conform to these rules
5978 may be rejected, even when they contain important and valuable stuff.
5980 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5982 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5983 see http://lists.denx.de/mailman/listinfo/u-boot
5985 When you send a patch, please include the following information with
5988 * For bug fixes: a description of the bug and how your patch fixes
5989 this bug. Please try to include a way of demonstrating that the
5990 patch actually fixes something.
5992 * For new features: a description of the feature and your
5995 * A CHANGELOG entry as plaintext (separate from the patch)
5997 * For major contributions, add a MAINTAINERS file with your
5998 information and associated file and directory references.
6000 * When you add support for a new board, don't forget to add a
6001 maintainer e-mail address to the boards.cfg file, too.
6003 * If your patch adds new configuration options, don't forget to
6004 document these in the README file.
6006 * The patch itself. If you are using git (which is *strongly*
6007 recommended) you can easily generate the patch using the
6008 "git format-patch". If you then use "git send-email" to send it to
6009 the U-Boot mailing list, you will avoid most of the common problems
6010 with some other mail clients.
6012 If you cannot use git, use "diff -purN OLD NEW". If your version of
6013 diff does not support these options, then get the latest version of
6016 The current directory when running this command shall be the parent
6017 directory of the U-Boot source tree (i. e. please make sure that
6018 your patch includes sufficient directory information for the
6021 We prefer patches as plain text. MIME attachments are discouraged,
6022 and compressed attachments must not be used.
6024 * If one logical set of modifications affects or creates several
6025 files, all these changes shall be submitted in a SINGLE patch file.
6027 * Changesets that contain different, unrelated modifications shall be
6028 submitted as SEPARATE patches, one patch per changeset.
6033 * Before sending the patch, run the buildman script on your patched
6034 source tree and make sure that no errors or warnings are reported
6035 for any of the boards.
6037 * Keep your modifications to the necessary minimum: A patch
6038 containing several unrelated changes or arbitrary reformats will be
6039 returned with a request to re-formatting / split it.
6041 * If you modify existing code, make sure that your new code does not
6042 add to the memory footprint of the code ;-) Small is beautiful!
6043 When adding new features, these should compile conditionally only
6044 (using #ifdef), and the resulting code with the new feature
6045 disabled must not need more memory than the old code without your
6048 * Remember that there is a size limit of 100 kB per message on the
6049 u-boot mailing list. Bigger patches will be moderated. If they are
6050 reasonable and not too big, they will be acknowledged. But patches
6051 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob