2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
834 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
835 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
836 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
837 CONFIG_CMD_DTT * Digital Therm and Thermostat
838 CONFIG_CMD_ECHO echo arguments
839 CONFIG_CMD_EDITENV edit env variable
840 CONFIG_CMD_EEPROM * EEPROM read/write support
841 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
842 CONFIG_CMD_ELF * bootelf, bootvx
843 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
844 CONFIG_CMD_ENV_FLAGS * display details about env flags
845 CONFIG_CMD_ENV_EXISTS * check existence of env variable
846 CONFIG_CMD_EXPORTENV * export the environment
847 CONFIG_CMD_EXT2 * ext2 command support
848 CONFIG_CMD_EXT4 * ext4 command support
849 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
850 that work for multiple fs types
851 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
852 CONFIG_CMD_SAVEENV saveenv
853 CONFIG_CMD_FDC * Floppy Disk Support
854 CONFIG_CMD_FAT * FAT command support
855 CONFIG_CMD_FLASH flinfo, erase, protect
856 CONFIG_CMD_FPGA FPGA device initialization support
857 CONFIG_CMD_FUSE * Device fuse support
858 CONFIG_CMD_GETTIME * Get time since boot
859 CONFIG_CMD_GO * the 'go' command (exec code)
860 CONFIG_CMD_GREPENV * search environment
861 CONFIG_CMD_HASH * calculate hash / digest
862 CONFIG_CMD_I2C * I2C serial bus support
863 CONFIG_CMD_IDE * IDE harddisk support
864 CONFIG_CMD_IMI iminfo
865 CONFIG_CMD_IMLS List all images found in NOR flash
866 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
867 CONFIG_CMD_IMMAP * IMMR dump support
868 CONFIG_CMD_IOTRACE * I/O tracing for debugging
869 CONFIG_CMD_IMPORTENV * import an environment
870 CONFIG_CMD_INI * import data from an ini file into the env
871 CONFIG_CMD_IRQ * irqinfo
872 CONFIG_CMD_ITEST Integer/string test of 2 values
873 CONFIG_CMD_JFFS2 * JFFS2 Support
874 CONFIG_CMD_KGDB * kgdb
875 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
876 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
878 CONFIG_CMD_LOADB loadb
879 CONFIG_CMD_LOADS loads
880 CONFIG_CMD_MD5SUM * print md5 message digest
881 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
882 CONFIG_CMD_MEMINFO * Display detailed memory information
883 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
885 CONFIG_CMD_MEMTEST * mtest
886 CONFIG_CMD_MISC Misc functions like sleep etc
887 CONFIG_CMD_MMC * MMC memory mapped support
888 CONFIG_CMD_MII * MII utility commands
889 CONFIG_CMD_MTDPARTS * MTD partition support
890 CONFIG_CMD_NAND * NAND support
891 CONFIG_CMD_NET bootp, tftpboot, rarpboot
892 CONFIG_CMD_NFS NFS support
893 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
894 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
895 CONFIG_CMD_PCI * pciinfo
896 CONFIG_CMD_PCMCIA * PCMCIA support
897 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
899 CONFIG_CMD_PORTIO * Port I/O
900 CONFIG_CMD_READ * Read raw data from partition
901 CONFIG_CMD_REGINFO * Register dump
902 CONFIG_CMD_RUN run command in env variable
903 CONFIG_CMD_SANDBOX * sb command to access sandbox features
904 CONFIG_CMD_SAVES * save S record dump
905 CONFIG_SCSI * SCSI Support
906 CONFIG_CMD_SDRAM * print SDRAM configuration information
907 (requires CONFIG_CMD_I2C)
908 CONFIG_CMD_SETGETDCR Support for DCR Register access
910 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
911 CONFIG_CMD_SHA1SUM * print sha1 memory digest
912 (requires CONFIG_CMD_MEMORY)
913 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
914 CONFIG_CMD_SOURCE "source" command Support
915 CONFIG_CMD_SPI * SPI serial bus support
916 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
917 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
918 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
919 CONFIG_CMD_TIMER * access to the system tick timer
920 CONFIG_CMD_USB * USB support
921 CONFIG_CMD_CDP * Cisco Discover Protocol support
922 CONFIG_CMD_MFSL * Microblaze FSL support
923 CONFIG_CMD_XIMG Load part of Multi Image
924 CONFIG_CMD_UUID * Generate random UUID or GUID string
926 EXAMPLE: If you want all functions except of network
927 support you can write:
929 #include "config_cmd_all.h"
930 #undef CONFIG_CMD_NET
933 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
935 Note: Don't enable the "icache" and "dcache" commands
936 (configuration option CONFIG_CMD_CACHE) unless you know
937 what you (and your U-Boot users) are doing. Data
938 cache cannot be enabled on systems like the 8xx or
939 8260 (where accesses to the IMMR region must be
940 uncached), and it cannot be disabled on all other
941 systems where we (mis-) use the data cache to hold an
942 initial stack and some data.
945 XXX - this list needs to get updated!
947 - Removal of commands
948 If no commands are needed to boot, you can disable
949 CONFIG_CMDLINE to remove them. In this case, the command line
950 will not be available, and when U-Boot wants to execute the
951 boot command (on start-up) it will call board_run_command()
952 instead. This can reduce image size significantly for very
953 simple boot procedures.
955 - Regular expression support:
957 If this variable is defined, U-Boot is linked against
958 the SLRE (Super Light Regular Expression) library,
959 which adds regex support to some commands, as for
960 example "env grep" and "setexpr".
964 If this variable is defined, U-Boot will use a device tree
965 to configure its devices, instead of relying on statically
966 compiled #defines in the board file. This option is
967 experimental and only available on a few boards. The device
968 tree is available in the global data as gd->fdt_blob.
970 U-Boot needs to get its device tree from somewhere. This can
971 be done using one of the three options below:
974 If this variable is defined, U-Boot will embed a device tree
975 binary in its image. This device tree file should be in the
976 board directory and called <soc>-<board>.dts. The binary file
977 is then picked up in board_init_f() and made available through
978 the global data structure as gd->blob.
981 If this variable is defined, U-Boot will build a device tree
982 binary. It will be called u-boot.dtb. Architecture-specific
983 code will locate it at run-time. Generally this works by:
985 cat u-boot.bin u-boot.dtb >image.bin
987 and in fact, U-Boot does this for you, creating a file called
988 u-boot-dtb.bin which is useful in the common case. You can
989 still use the individual files if you need something more
993 If this variable is defined, U-Boot will use the device tree
994 provided by the board at runtime instead of embedding one with
995 the image. Only boards defining board_fdt_blob_setup() support
996 this option (see include/fdtdec.h file).
1000 If this variable is defined, it enables watchdog
1001 support for the SoC. There must be support in the SoC
1002 specific code for a watchdog. For the 8xx and 8260
1003 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1004 register. When supported for a specific SoC is
1005 available, then no further board specific code should
1006 be needed to use it.
1009 When using a watchdog circuitry external to the used
1010 SoC, then define this variable and provide board
1011 specific code for the "hw_watchdog_reset" function.
1013 CONFIG_AT91_HW_WDT_TIMEOUT
1014 specify the timeout in seconds. default 2 seconds.
1017 CONFIG_VERSION_VARIABLE
1018 If this variable is defined, an environment variable
1019 named "ver" is created by U-Boot showing the U-Boot
1020 version as printed by the "version" command.
1021 Any change to this variable will be reverted at the
1026 When CONFIG_CMD_DATE is selected, the type of the RTC
1027 has to be selected, too. Define exactly one of the
1030 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1031 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1032 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1033 CONFIG_RTC_MC146818 - use MC146818 RTC
1034 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1035 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1036 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1037 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1038 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1039 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1040 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1041 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1042 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1045 Note that if the RTC uses I2C, then the I2C interface
1046 must also be configured. See I2C Support, below.
1049 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1051 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1052 chip-ngpio pairs that tell the PCA953X driver the number of
1053 pins supported by a particular chip.
1055 Note that if the GPIO device uses I2C, then the I2C interface
1056 must also be configured. See I2C Support, below.
1059 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1060 accesses and can checksum them or write a list of them out
1061 to memory. See the 'iotrace' command for details. This is
1062 useful for testing device drivers since it can confirm that
1063 the driver behaves the same way before and after a code
1064 change. Currently this is supported on sandbox and arm. To
1065 add support for your architecture, add '#include <iotrace.h>'
1066 to the bottom of arch/<arch>/include/asm/io.h and test.
1068 Example output from the 'iotrace stats' command is below.
1069 Note that if the trace buffer is exhausted, the checksum will
1070 still continue to operate.
1073 Start: 10000000 (buffer start address)
1074 Size: 00010000 (buffer size)
1075 Offset: 00000120 (current buffer offset)
1076 Output: 10000120 (start + offset)
1077 Count: 00000018 (number of trace records)
1078 CRC32: 9526fb66 (CRC32 of all trace records)
1080 - Timestamp Support:
1082 When CONFIG_TIMESTAMP is selected, the timestamp
1083 (date and time) of an image is printed by image
1084 commands like bootm or iminfo. This option is
1085 automatically enabled when you select CONFIG_CMD_DATE .
1087 - Partition Labels (disklabels) Supported:
1088 Zero or more of the following:
1089 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1090 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1091 Intel architecture, USB sticks, etc.
1092 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1093 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1094 bootloader. Note 2TB partition limit; see
1096 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1098 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1099 CONFIG_SCSI) you must configure support for at
1100 least one non-MTD partition type as well.
1103 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1104 board configurations files but used nowhere!
1106 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1107 be performed by calling the function
1108 ide_set_reset(int reset)
1109 which has to be defined in a board specific file
1114 Set this to enable ATAPI support.
1119 Set this to enable support for disks larger than 137GB
1120 Also look at CONFIG_SYS_64BIT_LBA.
1121 Whithout these , LBA48 support uses 32bit variables and will 'only'
1122 support disks up to 2.1TB.
1124 CONFIG_SYS_64BIT_LBA:
1125 When enabled, makes the IDE subsystem use 64bit sector addresses.
1129 At the moment only there is only support for the
1130 SYM53C8XX SCSI controller; define
1131 CONFIG_SCSI_SYM53C8XX to enable it.
1133 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1134 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1135 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1136 maximum numbers of LUNs, SCSI ID's and target
1138 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1140 The environment variable 'scsidevs' is set to the number of
1141 SCSI devices found during the last scan.
1143 - NETWORK Support (PCI):
1145 Support for Intel 8254x/8257x gigabit chips.
1148 Utility code for direct access to the SPI bus on Intel 8257x.
1149 This does not do anything useful unless you set at least one
1150 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1152 CONFIG_E1000_SPI_GENERIC
1153 Allow generic access to the SPI bus on the Intel 8257x, for
1154 example with the "sspi" command.
1157 Management command for E1000 devices. When used on devices
1158 with SPI support you can reprogram the EEPROM from U-Boot.
1161 Support for Intel 82557/82559/82559ER chips.
1162 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1163 write routine for first time initialisation.
1166 Support for Digital 2114x chips.
1167 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1168 modem chip initialisation (KS8761/QS6611).
1171 Support for National dp83815 chips.
1174 Support for National dp8382[01] gigabit chips.
1176 - NETWORK Support (other):
1178 CONFIG_DRIVER_AT91EMAC
1179 Support for AT91RM9200 EMAC.
1182 Define this to use reduced MII inteface
1184 CONFIG_DRIVER_AT91EMAC_QUIET
1185 If this defined, the driver is quiet.
1186 The driver doen't show link status messages.
1188 CONFIG_CALXEDA_XGMAC
1189 Support for the Calxeda XGMAC device
1192 Support for SMSC's LAN91C96 chips.
1194 CONFIG_LAN91C96_USE_32_BIT
1195 Define this to enable 32 bit addressing
1198 Support for SMSC's LAN91C111 chip
1200 CONFIG_SMC91111_BASE
1201 Define this to hold the physical address
1202 of the device (I/O space)
1204 CONFIG_SMC_USE_32_BIT
1205 Define this if data bus is 32 bits
1207 CONFIG_SMC_USE_IOFUNCS
1208 Define this to use i/o functions instead of macros
1209 (some hardware wont work with macros)
1211 CONFIG_DRIVER_TI_EMAC
1212 Support for davinci emac
1214 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1215 Define this if you have more then 3 PHYs.
1218 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1220 CONFIG_FTGMAC100_EGIGA
1221 Define this to use GE link update with gigabit PHY.
1222 Define this if FTGMAC100 is connected to gigabit PHY.
1223 If your system has 10/100 PHY only, it might not occur
1224 wrong behavior. Because PHY usually return timeout or
1225 useless data when polling gigabit status and gigabit
1226 control registers. This behavior won't affect the
1227 correctnessof 10/100 link speed update.
1230 Support for SMSC's LAN911x and LAN921x chips
1233 Define this to hold the physical address
1234 of the device (I/O space)
1236 CONFIG_SMC911X_32_BIT
1237 Define this if data bus is 32 bits
1239 CONFIG_SMC911X_16_BIT
1240 Define this if data bus is 16 bits. If your processor
1241 automatically converts one 32 bit word to two 16 bit
1242 words you may also try CONFIG_SMC911X_32_BIT.
1245 Support for Renesas on-chip Ethernet controller
1247 CONFIG_SH_ETHER_USE_PORT
1248 Define the number of ports to be used
1250 CONFIG_SH_ETHER_PHY_ADDR
1251 Define the ETH PHY's address
1253 CONFIG_SH_ETHER_CACHE_WRITEBACK
1254 If this option is set, the driver enables cache flush.
1258 Support for PWM module on the imx6.
1262 Support TPM devices.
1264 CONFIG_TPM_TIS_INFINEON
1265 Support for Infineon i2c bus TPM devices. Only one device
1266 per system is supported at this time.
1268 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1269 Define the burst count bytes upper limit
1272 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1274 CONFIG_TPM_ST33ZP24_I2C
1275 Support for STMicroelectronics ST33ZP24 I2C devices.
1276 Requires TPM_ST33ZP24 and I2C.
1278 CONFIG_TPM_ST33ZP24_SPI
1279 Support for STMicroelectronics ST33ZP24 SPI devices.
1280 Requires TPM_ST33ZP24 and SPI.
1282 CONFIG_TPM_ATMEL_TWI
1283 Support for Atmel TWI TPM device. Requires I2C support.
1286 Support for generic parallel port TPM devices. Only one device
1287 per system is supported at this time.
1289 CONFIG_TPM_TIS_BASE_ADDRESS
1290 Base address where the generic TPM device is mapped
1291 to. Contemporary x86 systems usually map it at
1295 Add tpm monitor functions.
1296 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1297 provides monitor access to authorized functions.
1300 Define this to enable the TPM support library which provides
1301 functional interfaces to some TPM commands.
1302 Requires support for a TPM device.
1304 CONFIG_TPM_AUTH_SESSIONS
1305 Define this to enable authorized functions in the TPM library.
1306 Requires CONFIG_TPM and CONFIG_SHA1.
1309 At the moment only the UHCI host controller is
1310 supported (PIP405, MIP405, MPC5200); define
1311 CONFIG_USB_UHCI to enable it.
1312 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1313 and define CONFIG_USB_STORAGE to enable the USB
1316 Supported are USB Keyboards and USB Floppy drives
1318 MPC5200 USB requires additional defines:
1320 for 528 MHz Clock: 0x0001bbbb
1324 for differential drivers: 0x00001000
1325 for single ended drivers: 0x00005000
1326 for differential drivers on PSC3: 0x00000100
1327 for single ended drivers on PSC3: 0x00004100
1328 CONFIG_SYS_USB_EVENT_POLL
1329 May be defined to allow interrupt polling
1330 instead of using asynchronous interrupts
1332 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1333 txfilltuning field in the EHCI controller on reset.
1335 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1336 HW module registers.
1339 Define the below if you wish to use the USB console.
1340 Once firmware is rebuilt from a serial console issue the
1341 command "setenv stdin usbtty; setenv stdout usbtty" and
1342 attach your USB cable. The Unix command "dmesg" should print
1343 it has found a new device. The environment variable usbtty
1344 can be set to gserial or cdc_acm to enable your device to
1345 appear to a USB host as a Linux gserial device or a
1346 Common Device Class Abstract Control Model serial device.
1347 If you select usbtty = gserial you should be able to enumerate
1349 # modprobe usbserial vendor=0xVendorID product=0xProductID
1350 else if using cdc_acm, simply setting the environment
1351 variable usbtty to be cdc_acm should suffice. The following
1352 might be defined in YourBoardName.h
1355 Define this to build a UDC device
1358 Define this to have a tty type of device available to
1359 talk to the UDC device
1362 Define this to enable the high speed support for usb
1363 device and usbtty. If this feature is enabled, a routine
1364 int is_usbd_high_speed(void)
1365 also needs to be defined by the driver to dynamically poll
1366 whether the enumeration has succeded at high speed or full
1369 CONFIG_SYS_CONSOLE_IS_IN_ENV
1370 Define this if you want stdin, stdout &/or stderr to
1374 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1375 Derive USB clock from external clock "blah"
1376 - CONFIG_SYS_USB_EXTC_CLK 0x02
1378 If you have a USB-IF assigned VendorID then you may wish to
1379 define your own vendor specific values either in BoardName.h
1380 or directly in usbd_vendor_info.h. If you don't define
1381 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1382 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1383 should pretend to be a Linux device to it's target host.
1385 CONFIG_USBD_MANUFACTURER
1386 Define this string as the name of your company for
1387 - CONFIG_USBD_MANUFACTURER "my company"
1389 CONFIG_USBD_PRODUCT_NAME
1390 Define this string as the name of your product
1391 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1393 CONFIG_USBD_VENDORID
1394 Define this as your assigned Vendor ID from the USB
1395 Implementors Forum. This *must* be a genuine Vendor ID
1396 to avoid polluting the USB namespace.
1397 - CONFIG_USBD_VENDORID 0xFFFF
1399 CONFIG_USBD_PRODUCTID
1400 Define this as the unique Product ID
1402 - CONFIG_USBD_PRODUCTID 0xFFFF
1404 - ULPI Layer Support:
1405 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1406 the generic ULPI layer. The generic layer accesses the ULPI PHY
1407 via the platform viewport, so you need both the genric layer and
1408 the viewport enabled. Currently only Chipidea/ARC based
1409 viewport is supported.
1410 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1411 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1412 If your ULPI phy needs a different reference clock than the
1413 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1414 the appropriate value in Hz.
1417 The MMC controller on the Intel PXA is supported. To
1418 enable this define CONFIG_MMC. The MMC can be
1419 accessed from the boot prompt by mapping the device
1420 to physical memory similar to flash. Command line is
1421 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1422 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1425 Support for Renesas on-chip MMCIF controller
1427 CONFIG_SH_MMCIF_ADDR
1428 Define the base address of MMCIF registers
1431 Define the clock frequency for MMCIF
1433 CONFIG_SUPPORT_EMMC_BOOT
1434 Enable some additional features of the eMMC boot partitions.
1436 CONFIG_SUPPORT_EMMC_RPMB
1437 Enable the commands for reading, writing and programming the
1438 key for the Replay Protection Memory Block partition in eMMC.
1440 - USB Device Firmware Update (DFU) class support:
1441 CONFIG_USB_FUNCTION_DFU
1442 This enables the USB portion of the DFU USB class
1445 This enables the command "dfu" which is used to have
1446 U-Boot create a DFU class device via USB. This command
1447 requires that the "dfu_alt_info" environment variable be
1448 set and define the alt settings to expose to the host.
1451 This enables support for exposing (e)MMC devices via DFU.
1454 This enables support for exposing NAND devices via DFU.
1457 This enables support for exposing RAM via DFU.
1458 Note: DFU spec refer to non-volatile memory usage, but
1459 allow usages beyond the scope of spec - here RAM usage,
1460 one that would help mostly the developer.
1462 CONFIG_SYS_DFU_DATA_BUF_SIZE
1463 Dfu transfer uses a buffer before writing data to the
1464 raw storage device. Make the size (in bytes) of this buffer
1465 configurable. The size of this buffer is also configurable
1466 through the "dfu_bufsiz" environment variable.
1468 CONFIG_SYS_DFU_MAX_FILE_SIZE
1469 When updating files rather than the raw storage device,
1470 we use a static buffer to copy the file into and then write
1471 the buffer once we've been given the whole file. Define
1472 this to the maximum filesize (in bytes) for the buffer.
1473 Default is 4 MiB if undefined.
1475 DFU_DEFAULT_POLL_TIMEOUT
1476 Poll timeout [ms], is the timeout a device can send to the
1477 host. The host must wait for this timeout before sending
1478 a subsequent DFU_GET_STATUS request to the device.
1480 DFU_MANIFEST_POLL_TIMEOUT
1481 Poll timeout [ms], which the device sends to the host when
1482 entering dfuMANIFEST state. Host waits this timeout, before
1483 sending again an USB request to the device.
1485 - USB Device Android Fastboot support:
1486 CONFIG_USB_FUNCTION_FASTBOOT
1487 This enables the USB part of the fastboot gadget
1490 This enables the command "fastboot" which enables the Android
1491 fastboot mode for the platform's USB device. Fastboot is a USB
1492 protocol for downloading images, flashing and device control
1493 used on Android devices.
1494 See doc/README.android-fastboot for more information.
1496 CONFIG_ANDROID_BOOT_IMAGE
1497 This enables support for booting images which use the Android
1498 image format header.
1500 CONFIG_FASTBOOT_BUF_ADDR
1501 The fastboot protocol requires a large memory buffer for
1502 downloads. Define this to the starting RAM address to use for
1505 CONFIG_FASTBOOT_BUF_SIZE
1506 The fastboot protocol requires a large memory buffer for
1507 downloads. This buffer should be as large as possible for a
1508 platform. Define this to the size available RAM for fastboot.
1510 CONFIG_FASTBOOT_FLASH
1511 The fastboot protocol includes a "flash" command for writing
1512 the downloaded image to a non-volatile storage device. Define
1513 this to enable the "fastboot flash" command.
1515 CONFIG_FASTBOOT_FLASH_MMC_DEV
1516 The fastboot "flash" command requires additional information
1517 regarding the non-volatile storage device. Define this to
1518 the eMMC device that fastboot should use to store the image.
1520 CONFIG_FASTBOOT_GPT_NAME
1521 The fastboot "flash" command supports writing the downloaded
1522 image to the Protective MBR and the Primary GUID Partition
1523 Table. (Additionally, this downloaded image is post-processed
1524 to generate and write the Backup GUID Partition Table.)
1525 This occurs when the specified "partition name" on the
1526 "fastboot flash" command line matches this value.
1527 The default is "gpt" if undefined.
1529 CONFIG_FASTBOOT_MBR_NAME
1530 The fastboot "flash" command supports writing the downloaded
1532 This occurs when the "partition name" specified on the
1533 "fastboot flash" command line matches this value.
1534 If not defined the default value "mbr" is used.
1536 - Journaling Flash filesystem support:
1538 Define these for a default partition on a NAND device
1540 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1541 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1542 Define these for a default partition on a NOR device
1544 - FAT(File Allocation Table) filesystem write function support:
1547 Define this to enable support for saving memory data as a
1548 file in FAT formatted partition.
1550 This will also enable the command "fatwrite" enabling the
1551 user to write files to FAT.
1553 - FAT(File Allocation Table) filesystem cluster size:
1554 CONFIG_FS_FAT_MAX_CLUSTSIZE
1556 Define the max cluster size for fat operations else
1557 a default value of 65536 will be defined.
1560 See Kconfig help for available keyboard drivers.
1564 Define this to enable a custom keyboard support.
1565 This simply calls drv_keyboard_init() which must be
1566 defined in your board-specific files. This option is deprecated
1567 and is only used by novena. For new boards, use driver model
1572 Enable the Freescale DIU video driver. Reference boards for
1573 SOCs that have a DIU should define this macro to enable DIU
1574 support, and should also define these other macros:
1579 CONFIG_VIDEO_SW_CURSOR
1580 CONFIG_VGA_AS_SINGLE_DEVICE
1582 CONFIG_VIDEO_BMP_LOGO
1584 The DIU driver will look for the 'video-mode' environment
1585 variable, and if defined, enable the DIU as a console during
1586 boot. See the documentation file doc/README.video for a
1587 description of this variable.
1589 - LCD Support: CONFIG_LCD
1591 Define this to enable LCD support (for output to LCD
1592 display); also select one of the supported displays
1593 by defining one of these:
1597 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1599 CONFIG_NEC_NL6448AC33:
1601 NEC NL6448AC33-18. Active, color, single scan.
1603 CONFIG_NEC_NL6448BC20
1605 NEC NL6448BC20-08. 6.5", 640x480.
1606 Active, color, single scan.
1608 CONFIG_NEC_NL6448BC33_54
1610 NEC NL6448BC33-54. 10.4", 640x480.
1611 Active, color, single scan.
1615 Sharp 320x240. Active, color, single scan.
1616 It isn't 16x9, and I am not sure what it is.
1618 CONFIG_SHARP_LQ64D341
1620 Sharp LQ64D341 display, 640x480.
1621 Active, color, single scan.
1625 HLD1045 display, 640x480.
1626 Active, color, single scan.
1630 Optrex CBL50840-2 NF-FW 99 22 M5
1632 Hitachi LMG6912RPFC-00T
1636 320x240. Black & white.
1638 CONFIG_LCD_ALIGNMENT
1640 Normally the LCD is page-aligned (typically 4KB). If this is
1641 defined then the LCD will be aligned to this value instead.
1642 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1643 here, since it is cheaper to change data cache settings on
1644 a per-section basis.
1649 Sometimes, for example if the display is mounted in portrait
1650 mode or even if it's mounted landscape but rotated by 180degree,
1651 we need to rotate our content of the display relative to the
1652 framebuffer, so that user can read the messages which are
1654 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1655 initialized with a given rotation from "vl_rot" out of
1656 "vidinfo_t" which is provided by the board specific code.
1657 The value for vl_rot is coded as following (matching to
1658 fbcon=rotate:<n> linux-kernel commandline):
1659 0 = no rotation respectively 0 degree
1660 1 = 90 degree rotation
1661 2 = 180 degree rotation
1662 3 = 270 degree rotation
1664 If CONFIG_LCD_ROTATION is not defined, the console will be
1665 initialized with 0degree rotation.
1669 Support drawing of RLE8-compressed bitmaps on the LCD.
1673 Enables an 'i2c edid' command which can read EDID
1674 information over I2C from an attached LCD display.
1676 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1678 If this option is set, the environment is checked for
1679 a variable "splashimage". If found, the usual display
1680 of logo, copyright and system information on the LCD
1681 is suppressed and the BMP image at the address
1682 specified in "splashimage" is loaded instead. The
1683 console is redirected to the "nulldev", too. This
1684 allows for a "silent" boot where a splash screen is
1685 loaded very quickly after power-on.
1687 CONFIG_SPLASHIMAGE_GUARD
1689 If this option is set, then U-Boot will prevent the environment
1690 variable "splashimage" from being set to a problematic address
1691 (see doc/README.displaying-bmps).
1692 This option is useful for targets where, due to alignment
1693 restrictions, an improperly aligned BMP image will cause a data
1694 abort. If you think you will not have problems with unaligned
1695 accesses (for example because your toolchain prevents them)
1696 there is no need to set this option.
1698 CONFIG_SPLASH_SCREEN_ALIGN
1700 If this option is set the splash image can be freely positioned
1701 on the screen. Environment variable "splashpos" specifies the
1702 position as "x,y". If a positive number is given it is used as
1703 number of pixel from left/top. If a negative number is given it
1704 is used as number of pixel from right/bottom. You can also
1705 specify 'm' for centering the image.
1708 setenv splashpos m,m
1709 => image at center of screen
1711 setenv splashpos 30,20
1712 => image at x = 30 and y = 20
1714 setenv splashpos -10,m
1715 => vertically centered image
1716 at x = dspWidth - bmpWidth - 9
1718 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1720 If this option is set, additionally to standard BMP
1721 images, gzipped BMP images can be displayed via the
1722 splashscreen support or the bmp command.
1724 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1726 If this option is set, 8-bit RLE compressed BMP images
1727 can be displayed via the splashscreen support or the
1730 - Compression support:
1733 Enabled by default to support gzip compressed images.
1737 If this option is set, support for bzip2 compressed
1738 images is included. If not, only uncompressed and gzip
1739 compressed images are supported.
1741 NOTE: the bzip2 algorithm requires a lot of RAM, so
1742 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1747 If this option is set, support for lzma compressed
1750 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1751 requires an amount of dynamic memory that is given by the
1754 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1756 Where lc and lp stand for, respectively, Literal context bits
1757 and Literal pos bits.
1759 This value is upper-bounded by 14MB in the worst case. Anyway,
1760 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1761 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1762 a very small buffer.
1764 Use the lzmainfo tool to determinate the lc and lp values and
1765 then calculate the amount of needed dynamic memory (ensuring
1766 the appropriate CONFIG_SYS_MALLOC_LEN value).
1770 If this option is set, support for LZO compressed images
1776 The address of PHY on MII bus.
1778 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1780 The clock frequency of the MII bus
1784 If this option is set, support for speed/duplex
1785 detection of gigabit PHY is included.
1787 CONFIG_PHY_RESET_DELAY
1789 Some PHY like Intel LXT971A need extra delay after
1790 reset before any MII register access is possible.
1791 For such PHY, set this option to the usec delay
1792 required. (minimum 300usec for LXT971A)
1794 CONFIG_PHY_CMD_DELAY (ppc4xx)
1796 Some PHY like Intel LXT971A need extra delay after
1797 command issued before MII status register can be read
1802 Define a default value for the IP address to use for
1803 the default Ethernet interface, in case this is not
1804 determined through e.g. bootp.
1805 (Environment variable "ipaddr")
1807 - Server IP address:
1810 Defines a default value for the IP address of a TFTP
1811 server to contact when using the "tftboot" command.
1812 (Environment variable "serverip")
1814 CONFIG_KEEP_SERVERADDR
1816 Keeps the server's MAC address, in the env 'serveraddr'
1817 for passing to bootargs (like Linux's netconsole option)
1819 - Gateway IP address:
1822 Defines a default value for the IP address of the
1823 default router where packets to other networks are
1825 (Environment variable "gatewayip")
1830 Defines a default value for the subnet mask (or
1831 routing prefix) which is used to determine if an IP
1832 address belongs to the local subnet or needs to be
1833 forwarded through a router.
1834 (Environment variable "netmask")
1836 - Multicast TFTP Mode:
1839 Defines whether you want to support multicast TFTP as per
1840 rfc-2090; for example to work with atftp. Lets lots of targets
1841 tftp down the same boot image concurrently. Note: the Ethernet
1842 driver in use must provide a function: mcast() to join/leave a
1845 - BOOTP Recovery Mode:
1846 CONFIG_BOOTP_RANDOM_DELAY
1848 If you have many targets in a network that try to
1849 boot using BOOTP, you may want to avoid that all
1850 systems send out BOOTP requests at precisely the same
1851 moment (which would happen for instance at recovery
1852 from a power failure, when all systems will try to
1853 boot, thus flooding the BOOTP server. Defining
1854 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1855 inserted before sending out BOOTP requests. The
1856 following delays are inserted then:
1858 1st BOOTP request: delay 0 ... 1 sec
1859 2nd BOOTP request: delay 0 ... 2 sec
1860 3rd BOOTP request: delay 0 ... 4 sec
1862 BOOTP requests: delay 0 ... 8 sec
1864 CONFIG_BOOTP_ID_CACHE_SIZE
1866 BOOTP packets are uniquely identified using a 32-bit ID. The
1867 server will copy the ID from client requests to responses and
1868 U-Boot will use this to determine if it is the destination of
1869 an incoming response. Some servers will check that addresses
1870 aren't in use before handing them out (usually using an ARP
1871 ping) and therefore take up to a few hundred milliseconds to
1872 respond. Network congestion may also influence the time it
1873 takes for a response to make it back to the client. If that
1874 time is too long, U-Boot will retransmit requests. In order
1875 to allow earlier responses to still be accepted after these
1876 retransmissions, U-Boot's BOOTP client keeps a small cache of
1877 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1878 cache. The default is to keep IDs for up to four outstanding
1879 requests. Increasing this will allow U-Boot to accept offers
1880 from a BOOTP client in networks with unusually high latency.
1882 - DHCP Advanced Options:
1883 You can fine tune the DHCP functionality by defining
1884 CONFIG_BOOTP_* symbols:
1886 CONFIG_BOOTP_SUBNETMASK
1887 CONFIG_BOOTP_GATEWAY
1888 CONFIG_BOOTP_HOSTNAME
1889 CONFIG_BOOTP_NISDOMAIN
1890 CONFIG_BOOTP_BOOTPATH
1891 CONFIG_BOOTP_BOOTFILESIZE
1894 CONFIG_BOOTP_SEND_HOSTNAME
1895 CONFIG_BOOTP_NTPSERVER
1896 CONFIG_BOOTP_TIMEOFFSET
1897 CONFIG_BOOTP_VENDOREX
1898 CONFIG_BOOTP_MAY_FAIL
1900 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1901 environment variable, not the BOOTP server.
1903 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1904 after the configured retry count, the call will fail
1905 instead of starting over. This can be used to fail over
1906 to Link-local IP address configuration if the DHCP server
1909 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1910 serverip from a DHCP server, it is possible that more
1911 than one DNS serverip is offered to the client.
1912 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1913 serverip will be stored in the additional environment
1914 variable "dnsip2". The first DNS serverip is always
1915 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1918 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1919 to do a dynamic update of a DNS server. To do this, they
1920 need the hostname of the DHCP requester.
1921 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1922 of the "hostname" environment variable is passed as
1923 option 12 to the DHCP server.
1925 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1927 A 32bit value in microseconds for a delay between
1928 receiving a "DHCP Offer" and sending the "DHCP Request".
1929 This fixes a problem with certain DHCP servers that don't
1930 respond 100% of the time to a "DHCP request". E.g. On an
1931 AT91RM9200 processor running at 180MHz, this delay needed
1932 to be *at least* 15,000 usec before a Windows Server 2003
1933 DHCP server would reply 100% of the time. I recommend at
1934 least 50,000 usec to be safe. The alternative is to hope
1935 that one of the retries will be successful but note that
1936 the DHCP timeout and retry process takes a longer than
1939 - Link-local IP address negotiation:
1940 Negotiate with other link-local clients on the local network
1941 for an address that doesn't require explicit configuration.
1942 This is especially useful if a DHCP server cannot be guaranteed
1943 to exist in all environments that the device must operate.
1945 See doc/README.link-local for more information.
1948 CONFIG_CDP_DEVICE_ID
1950 The device id used in CDP trigger frames.
1952 CONFIG_CDP_DEVICE_ID_PREFIX
1954 A two character string which is prefixed to the MAC address
1959 A printf format string which contains the ascii name of
1960 the port. Normally is set to "eth%d" which sets
1961 eth0 for the first Ethernet, eth1 for the second etc.
1963 CONFIG_CDP_CAPABILITIES
1965 A 32bit integer which indicates the device capabilities;
1966 0x00000010 for a normal host which does not forwards.
1970 An ascii string containing the version of the software.
1974 An ascii string containing the name of the platform.
1978 A 32bit integer sent on the trigger.
1980 CONFIG_CDP_POWER_CONSUMPTION
1982 A 16bit integer containing the power consumption of the
1983 device in .1 of milliwatts.
1985 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1987 A byte containing the id of the VLAN.
1989 - Status LED: CONFIG_LED_STATUS
1991 Several configurations allow to display the current
1992 status using a LED. For instance, the LED will blink
1993 fast while running U-Boot code, stop blinking as
1994 soon as a reply to a BOOTP request was received, and
1995 start blinking slow once the Linux kernel is running
1996 (supported by a status LED driver in the Linux
1997 kernel). Defining CONFIG_LED_STATUS enables this
2002 CONFIG_LED_STATUS_GPIO
2003 The status LED can be connected to a GPIO pin.
2004 In such cases, the gpio_led driver can be used as a
2005 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2006 to include the gpio_led driver in the U-Boot binary.
2008 CONFIG_GPIO_LED_INVERTED_TABLE
2009 Some GPIO connected LEDs may have inverted polarity in which
2010 case the GPIO high value corresponds to LED off state and
2011 GPIO low value corresponds to LED on state.
2012 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2013 with a list of GPIO LEDs that have inverted polarity.
2015 - CAN Support: CONFIG_CAN_DRIVER
2017 Defining CONFIG_CAN_DRIVER enables CAN driver support
2018 on those systems that support this (optional)
2019 feature, like the TQM8xxL modules.
2021 - I2C Support: CONFIG_SYS_I2C
2023 This enable the NEW i2c subsystem, and will allow you to use
2024 i2c commands at the u-boot command line (as long as you set
2025 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2026 based realtime clock chips or other i2c devices. See
2027 common/cmd_i2c.c for a description of the command line
2030 ported i2c driver to the new framework:
2031 - drivers/i2c/soft_i2c.c:
2032 - activate first bus with CONFIG_SYS_I2C_SOFT define
2033 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2034 for defining speed and slave address
2035 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2036 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2037 for defining speed and slave address
2038 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2039 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2040 for defining speed and slave address
2041 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2042 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2043 for defining speed and slave address
2045 - drivers/i2c/fsl_i2c.c:
2046 - activate i2c driver with CONFIG_SYS_I2C_FSL
2047 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2048 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2049 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2051 - If your board supports a second fsl i2c bus, define
2052 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2053 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2054 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2057 - drivers/i2c/tegra_i2c.c:
2058 - activate this driver with CONFIG_SYS_I2C_TEGRA
2059 - This driver adds 4 i2c buses with a fix speed from
2060 100000 and the slave addr 0!
2062 - drivers/i2c/ppc4xx_i2c.c
2063 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2064 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2065 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2067 - drivers/i2c/i2c_mxc.c
2068 - activate this driver with CONFIG_SYS_I2C_MXC
2069 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2070 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2071 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2072 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2073 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2074 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2075 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2076 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2077 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2078 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2079 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2080 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2081 If those defines are not set, default value is 100000
2082 for speed, and 0 for slave.
2084 - drivers/i2c/rcar_i2c.c:
2085 - activate this driver with CONFIG_SYS_I2C_RCAR
2086 - This driver adds 4 i2c buses
2088 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2089 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2090 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2091 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2092 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2093 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2094 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2095 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2096 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2098 - drivers/i2c/sh_i2c.c:
2099 - activate this driver with CONFIG_SYS_I2C_SH
2100 - This driver adds from 2 to 5 i2c buses
2102 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2103 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2104 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2105 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2106 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2107 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2108 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2109 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2110 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2111 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2112 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2114 - drivers/i2c/omap24xx_i2c.c
2115 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2116 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2117 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2118 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2119 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2120 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2121 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2122 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2123 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2124 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2125 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2127 - drivers/i2c/zynq_i2c.c
2128 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2129 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2130 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2132 - drivers/i2c/s3c24x0_i2c.c:
2133 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2134 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2135 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2136 with a fix speed from 100000 and the slave addr 0!
2138 - drivers/i2c/ihs_i2c.c
2139 - activate this driver with CONFIG_SYS_I2C_IHS
2140 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2141 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2142 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2143 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2144 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2145 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2146 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2147 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2148 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2149 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2150 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2151 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2152 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2153 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2154 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2155 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2156 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2157 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2158 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2159 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2160 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2164 CONFIG_SYS_NUM_I2C_BUSES
2165 Hold the number of i2c buses you want to use.
2167 CONFIG_SYS_I2C_DIRECT_BUS
2168 define this, if you don't use i2c muxes on your hardware.
2169 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2172 CONFIG_SYS_I2C_MAX_HOPS
2173 define how many muxes are maximal consecutively connected
2174 on one i2c bus. If you not use i2c muxes, omit this
2177 CONFIG_SYS_I2C_BUSES
2178 hold a list of buses you want to use, only used if
2179 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2180 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2181 CONFIG_SYS_NUM_I2C_BUSES = 9:
2183 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2184 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2185 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2186 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2187 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2188 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2189 {1, {I2C_NULL_HOP}}, \
2190 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2191 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2195 bus 0 on adapter 0 without a mux
2196 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2197 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2198 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2199 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2200 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2201 bus 6 on adapter 1 without a mux
2202 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2203 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2205 If you do not have i2c muxes on your board, omit this define.
2209 - Legacy I2C Support: CONFIG_SOFT_I2C
2211 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2212 provides the following compelling advantages:
2214 - more than one i2c adapter is usable
2215 - approved multibus support
2216 - better i2c mux support
2218 ** CONFIG_SOFT_I2C is now being removed **
2220 With CONFIG_SOFT_I2C you will need to define
2221 CONFIG_SYS_I2C_SPEED to be the frequency (in Hz) at which you
2222 wish your i2c bus to run and CONFIG_SYS_I2C_SLAVE to be the
2223 address of this node (ie the CPU's i2c node address).
2225 Now, the u-boot i2c code for the mpc8xx
2226 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2227 and so its address should therefore be cleared to 0 (See,
2228 eg, MPC823e User's Manual p.16-473). So, set
2229 CONFIG_SYS_I2C_SLAVE to 0.
2231 When a board is reset during an i2c bus transfer
2232 chips might think that the current transfer is still
2233 in progress. Reset the slave devices by sending start
2234 commands until the slave device responds.
2236 That's all that's required for CONFIG_HARD_I2C.
2238 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2239 then the following macros need to be defined (examples are
2240 from include/configs/lwmon.h):
2244 (Optional). Any commands necessary to enable the I2C
2245 controller or configure ports.
2247 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2251 (Only for MPC8260 CPU). The I/O port to use (the code
2252 assumes both bits are on the same port). Valid values
2253 are 0..3 for ports A..D.
2257 The code necessary to make the I2C data line active
2258 (driven). If the data line is open collector, this
2261 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2265 The code necessary to make the I2C data line tri-stated
2266 (inactive). If the data line is open collector, this
2269 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2273 Code that returns true if the I2C data line is high,
2276 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2280 If <bit> is true, sets the I2C data line high. If it
2281 is false, it clears it (low).
2283 eg: #define I2C_SDA(bit) \
2284 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2285 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2289 If <bit> is true, sets the I2C clock line high. If it
2290 is false, it clears it (low).
2292 eg: #define I2C_SCL(bit) \
2293 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2294 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2298 This delay is invoked four times per clock cycle so this
2299 controls the rate of data transfer. The data rate thus
2300 is 1 / (I2C_DELAY * 4). Often defined to be something
2303 #define I2C_DELAY udelay(2)
2305 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2307 If your arch supports the generic GPIO framework (asm/gpio.h),
2308 then you may alternatively define the two GPIOs that are to be
2309 used as SCL / SDA. Any of the previous I2C_xxx macros will
2310 have GPIO-based defaults assigned to them as appropriate.
2312 You should define these to the GPIO value as given directly to
2313 the generic GPIO functions.
2315 CONFIG_SYS_I2C_INIT_BOARD
2317 When a board is reset during an i2c bus transfer
2318 chips might think that the current transfer is still
2319 in progress. On some boards it is possible to access
2320 the i2c SCLK line directly, either by using the
2321 processor pin as a GPIO or by having a second pin
2322 connected to the bus. If this option is defined a
2323 custom i2c_init_board() routine in boards/xxx/board.c
2324 is run early in the boot sequence.
2326 CONFIG_I2C_MULTI_BUS
2328 This option allows the use of multiple I2C buses, each of which
2329 must have a controller. At any point in time, only one bus is
2330 active. To switch to a different bus, use the 'i2c dev' command.
2331 Note that bus numbering is zero-based.
2333 CONFIG_SYS_I2C_NOPROBES
2335 This option specifies a list of I2C devices that will be skipped
2336 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2337 is set, specify a list of bus-device pairs. Otherwise, specify
2338 a 1D array of device addresses
2341 #undef CONFIG_I2C_MULTI_BUS
2342 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2344 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2346 #define CONFIG_I2C_MULTI_BUS
2347 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2349 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2351 CONFIG_SYS_SPD_BUS_NUM
2353 If defined, then this indicates the I2C bus number for DDR SPD.
2354 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2356 CONFIG_SYS_RTC_BUS_NUM
2358 If defined, then this indicates the I2C bus number for the RTC.
2359 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2361 CONFIG_SYS_DTT_BUS_NUM
2363 If defined, then this indicates the I2C bus number for the DTT.
2364 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2366 CONFIG_SYS_I2C_DTT_ADDR:
2368 If defined, specifies the I2C address of the DTT device.
2369 If not defined, then U-Boot uses predefined value for
2370 specified DTT device.
2372 CONFIG_SOFT_I2C_READ_REPEATED_START
2374 defining this will force the i2c_read() function in
2375 the soft_i2c driver to perform an I2C repeated start
2376 between writing the address pointer and reading the
2377 data. If this define is omitted the default behaviour
2378 of doing a stop-start sequence will be used. Most I2C
2379 devices can use either method, but some require one or
2382 - SPI Support: CONFIG_SPI
2384 Enables SPI driver (so far only tested with
2385 SPI EEPROM, also an instance works with Crystal A/D and
2386 D/As on the SACSng board)
2390 Enables the driver for SPI controller on SuperH. Currently
2391 only SH7757 is supported.
2395 Enables a software (bit-bang) SPI driver rather than
2396 using hardware support. This is a general purpose
2397 driver that only requires three general I/O port pins
2398 (two outputs, one input) to function. If this is
2399 defined, the board configuration must define several
2400 SPI configuration items (port pins to use, etc). For
2401 an example, see include/configs/sacsng.h.
2405 Enables a hardware SPI driver for general-purpose reads
2406 and writes. As with CONFIG_SOFT_SPI, the board configuration
2407 must define a list of chip-select function pointers.
2408 Currently supported on some MPC8xxx processors. For an
2409 example, see include/configs/mpc8349emds.h.
2413 Enables the driver for the SPI controllers on i.MX and MXC
2414 SoCs. Currently i.MX31/35/51 are supported.
2416 CONFIG_SYS_SPI_MXC_WAIT
2417 Timeout for waiting until spi transfer completed.
2418 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2420 - FPGA Support: CONFIG_FPGA
2422 Enables FPGA subsystem.
2424 CONFIG_FPGA_<vendor>
2426 Enables support for specific chip vendors.
2429 CONFIG_FPGA_<family>
2431 Enables support for FPGA family.
2432 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2436 Specify the number of FPGA devices to support.
2438 CONFIG_CMD_FPGA_LOADMK
2440 Enable support for fpga loadmk command
2442 CONFIG_CMD_FPGA_LOADP
2444 Enable support for fpga loadp command - load partial bitstream
2446 CONFIG_CMD_FPGA_LOADBP
2448 Enable support for fpga loadbp command - load partial bitstream
2451 CONFIG_SYS_FPGA_PROG_FEEDBACK
2453 Enable printing of hash marks during FPGA configuration.
2455 CONFIG_SYS_FPGA_CHECK_BUSY
2457 Enable checks on FPGA configuration interface busy
2458 status by the configuration function. This option
2459 will require a board or device specific function to
2464 If defined, a function that provides delays in the FPGA
2465 configuration driver.
2467 CONFIG_SYS_FPGA_CHECK_CTRLC
2468 Allow Control-C to interrupt FPGA configuration
2470 CONFIG_SYS_FPGA_CHECK_ERROR
2472 Check for configuration errors during FPGA bitfile
2473 loading. For example, abort during Virtex II
2474 configuration if the INIT_B line goes low (which
2475 indicated a CRC error).
2477 CONFIG_SYS_FPGA_WAIT_INIT
2479 Maximum time to wait for the INIT_B line to de-assert
2480 after PROB_B has been de-asserted during a Virtex II
2481 FPGA configuration sequence. The default time is 500
2484 CONFIG_SYS_FPGA_WAIT_BUSY
2486 Maximum time to wait for BUSY to de-assert during
2487 Virtex II FPGA configuration. The default is 5 ms.
2489 CONFIG_SYS_FPGA_WAIT_CONFIG
2491 Time to wait after FPGA configuration. The default is
2494 - Configuration Management:
2497 Some SoCs need special image types (e.g. U-Boot binary
2498 with a special header) as build targets. By defining
2499 CONFIG_BUILD_TARGET in the SoC / board header, this
2500 special image will be automatically built upon calling
2505 If defined, this string will be added to the U-Boot
2506 version information (U_BOOT_VERSION)
2508 - Vendor Parameter Protection:
2510 U-Boot considers the values of the environment
2511 variables "serial#" (Board Serial Number) and
2512 "ethaddr" (Ethernet Address) to be parameters that
2513 are set once by the board vendor / manufacturer, and
2514 protects these variables from casual modification by
2515 the user. Once set, these variables are read-only,
2516 and write or delete attempts are rejected. You can
2517 change this behaviour:
2519 If CONFIG_ENV_OVERWRITE is #defined in your config
2520 file, the write protection for vendor parameters is
2521 completely disabled. Anybody can change or delete
2524 Alternatively, if you define _both_ an ethaddr in the
2525 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2526 Ethernet address is installed in the environment,
2527 which can be changed exactly ONCE by the user. [The
2528 serial# is unaffected by this, i. e. it remains
2531 The same can be accomplished in a more flexible way
2532 for any variable by configuring the type of access
2533 to allow for those variables in the ".flags" variable
2534 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2539 Define this variable to enable the reservation of
2540 "protected RAM", i. e. RAM which is not overwritten
2541 by U-Boot. Define CONFIG_PRAM to hold the number of
2542 kB you want to reserve for pRAM. You can overwrite
2543 this default value by defining an environment
2544 variable "pram" to the number of kB you want to
2545 reserve. Note that the board info structure will
2546 still show the full amount of RAM. If pRAM is
2547 reserved, a new environment variable "mem" will
2548 automatically be defined to hold the amount of
2549 remaining RAM in a form that can be passed as boot
2550 argument to Linux, for instance like that:
2552 setenv bootargs ... mem=\${mem}
2555 This way you can tell Linux not to use this memory,
2556 either, which results in a memory region that will
2557 not be affected by reboots.
2559 *WARNING* If your board configuration uses automatic
2560 detection of the RAM size, you must make sure that
2561 this memory test is non-destructive. So far, the
2562 following board configurations are known to be
2565 IVMS8, IVML24, SPD8xx, TQM8xxL,
2566 HERMES, IP860, RPXlite, LWMON,
2569 - Access to physical memory region (> 4GB)
2570 Some basic support is provided for operations on memory not
2571 normally accessible to U-Boot - e.g. some architectures
2572 support access to more than 4GB of memory on 32-bit
2573 machines using physical address extension or similar.
2574 Define CONFIG_PHYSMEM to access this basic support, which
2575 currently only supports clearing the memory.
2580 Define this variable to stop the system in case of a
2581 fatal error, so that you have to reset it manually.
2582 This is probably NOT a good idea for an embedded
2583 system where you want the system to reboot
2584 automatically as fast as possible, but it may be
2585 useful during development since you can try to debug
2586 the conditions that lead to the situation.
2588 CONFIG_NET_RETRY_COUNT
2590 This variable defines the number of retries for
2591 network operations like ARP, RARP, TFTP, or BOOTP
2592 before giving up the operation. If not defined, a
2593 default value of 5 is used.
2597 Timeout waiting for an ARP reply in milliseconds.
2601 Timeout in milliseconds used in NFS protocol.
2602 If you encounter "ERROR: Cannot umount" in nfs command,
2603 try longer timeout such as
2604 #define CONFIG_NFS_TIMEOUT 10000UL
2606 - Command Interpreter:
2607 CONFIG_AUTO_COMPLETE
2609 Enable auto completion of commands using TAB.
2611 CONFIG_SYS_PROMPT_HUSH_PS2
2613 This defines the secondary prompt string, which is
2614 printed when the command interpreter needs more input
2615 to complete a command. Usually "> ".
2619 In the current implementation, the local variables
2620 space and global environment variables space are
2621 separated. Local variables are those you define by
2622 simply typing `name=value'. To access a local
2623 variable later on, you have write `$name' or
2624 `${name}'; to execute the contents of a variable
2625 directly type `$name' at the command prompt.
2627 Global environment variables are those you use
2628 setenv/printenv to work with. To run a command stored
2629 in such a variable, you need to use the run command,
2630 and you must not use the '$' sign to access them.
2632 To store commands and special characters in a
2633 variable, please use double quotation marks
2634 surrounding the whole text of the variable, instead
2635 of the backslashes before semicolons and special
2638 - Command Line Editing and History:
2639 CONFIG_CMDLINE_EDITING
2641 Enable editing and History functions for interactive
2642 command line input operations
2644 - Command Line PS1/PS2 support:
2645 CONFIG_CMDLINE_PS_SUPPORT
2647 Enable support for changing the command prompt string
2648 at run-time. Only static string is supported so far.
2649 The string is obtained from environment variables PS1
2652 - Default Environment:
2653 CONFIG_EXTRA_ENV_SETTINGS
2655 Define this to contain any number of null terminated
2656 strings (variable = value pairs) that will be part of
2657 the default environment compiled into the boot image.
2659 For example, place something like this in your
2660 board's config file:
2662 #define CONFIG_EXTRA_ENV_SETTINGS \
2666 Warning: This method is based on knowledge about the
2667 internal format how the environment is stored by the
2668 U-Boot code. This is NOT an official, exported
2669 interface! Although it is unlikely that this format
2670 will change soon, there is no guarantee either.
2671 You better know what you are doing here.
2673 Note: overly (ab)use of the default environment is
2674 discouraged. Make sure to check other ways to preset
2675 the environment like the "source" command or the
2678 CONFIG_ENV_VARS_UBOOT_CONFIG
2680 Define this in order to add variables describing the
2681 U-Boot build configuration to the default environment.
2682 These will be named arch, cpu, board, vendor, and soc.
2684 Enabling this option will cause the following to be defined:
2692 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2694 Define this in order to add variables describing certain
2695 run-time determined information about the hardware to the
2696 environment. These will be named board_name, board_rev.
2698 CONFIG_DELAY_ENVIRONMENT
2700 Normally the environment is loaded when the board is
2701 initialised so that it is available to U-Boot. This inhibits
2702 that so that the environment is not available until
2703 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2704 this is instead controlled by the value of
2705 /config/load-environment.
2707 - DataFlash Support:
2708 CONFIG_HAS_DATAFLASH
2710 Defining this option enables DataFlash features and
2711 allows to read/write in Dataflash via the standard
2714 - Serial Flash support
2717 Defining this option enables SPI flash commands
2718 'sf probe/read/write/erase/update'.
2720 Usage requires an initial 'probe' to define the serial
2721 flash parameters, followed by read/write/erase/update
2724 The following defaults may be provided by the platform
2725 to handle the common case when only a single serial
2726 flash is present on the system.
2728 CONFIG_SF_DEFAULT_BUS Bus identifier
2729 CONFIG_SF_DEFAULT_CS Chip-select
2730 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2731 CONFIG_SF_DEFAULT_SPEED in Hz
2735 Define this option to include a destructive SPI flash
2738 CONFIG_SF_DUAL_FLASH Dual flash memories
2740 Define this option to use dual flash support where two flash
2741 memories can be connected with a given cs line.
2742 Currently Xilinx Zynq qspi supports these type of connections.
2744 - SystemACE Support:
2747 Adding this option adds support for Xilinx SystemACE
2748 chips attached via some sort of local bus. The address
2749 of the chip must also be defined in the
2750 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2752 #define CONFIG_SYSTEMACE
2753 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2755 When SystemACE support is added, the "ace" device type
2756 becomes available to the fat commands, i.e. fatls.
2758 - TFTP Fixed UDP Port:
2761 If this is defined, the environment variable tftpsrcp
2762 is used to supply the TFTP UDP source port value.
2763 If tftpsrcp isn't defined, the normal pseudo-random port
2764 number generator is used.
2766 Also, the environment variable tftpdstp is used to supply
2767 the TFTP UDP destination port value. If tftpdstp isn't
2768 defined, the normal port 69 is used.
2770 The purpose for tftpsrcp is to allow a TFTP server to
2771 blindly start the TFTP transfer using the pre-configured
2772 target IP address and UDP port. This has the effect of
2773 "punching through" the (Windows XP) firewall, allowing
2774 the remainder of the TFTP transfer to proceed normally.
2775 A better solution is to properly configure the firewall,
2776 but sometimes that is not allowed.
2781 This enables a generic 'hash' command which can produce
2782 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2786 Enable the hash verify command (hash -v). This adds to code
2789 CONFIG_SHA1 - This option enables support of hashing using SHA1
2790 algorithm. The hash is calculated in software.
2791 CONFIG_SHA256 - This option enables support of hashing using
2792 SHA256 algorithm. The hash is calculated in software.
2793 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2794 for SHA1/SHA256 hashing.
2795 This affects the 'hash' command and also the
2796 hash_lookup_algo() function.
2797 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2798 hardware-acceleration for SHA1/SHA256 progressive hashing.
2799 Data can be streamed in a block at a time and the hashing
2800 is performed in hardware.
2802 Note: There is also a sha1sum command, which should perhaps
2803 be deprecated in favour of 'hash sha1'.
2805 - Freescale i.MX specific commands:
2806 CONFIG_CMD_HDMIDETECT
2807 This enables 'hdmidet' command which returns true if an
2808 HDMI monitor is detected. This command is i.MX 6 specific.
2810 - bootcount support:
2811 CONFIG_BOOTCOUNT_LIMIT
2813 This enables the bootcounter support, see:
2814 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2817 enable special bootcounter support on at91sam9xe based boards.
2819 enable special bootcounter support on da850 based boards.
2820 CONFIG_BOOTCOUNT_RAM
2821 enable support for the bootcounter in RAM
2822 CONFIG_BOOTCOUNT_I2C
2823 enable support for the bootcounter on an i2c (like RTC) device.
2824 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2825 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2827 CONFIG_BOOTCOUNT_ALEN = address len
2829 - Show boot progress:
2830 CONFIG_SHOW_BOOT_PROGRESS
2832 Defining this option allows to add some board-
2833 specific code (calling a user-provided function
2834 "show_boot_progress(int)") that enables you to show
2835 the system's boot progress on some display (for
2836 example, some LED's) on your board. At the moment,
2837 the following checkpoints are implemented:
2840 Legacy uImage format:
2843 1 common/cmd_bootm.c before attempting to boot an image
2844 -1 common/cmd_bootm.c Image header has bad magic number
2845 2 common/cmd_bootm.c Image header has correct magic number
2846 -2 common/cmd_bootm.c Image header has bad checksum
2847 3 common/cmd_bootm.c Image header has correct checksum
2848 -3 common/cmd_bootm.c Image data has bad checksum
2849 4 common/cmd_bootm.c Image data has correct checksum
2850 -4 common/cmd_bootm.c Image is for unsupported architecture
2851 5 common/cmd_bootm.c Architecture check OK
2852 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2853 6 common/cmd_bootm.c Image Type check OK
2854 -6 common/cmd_bootm.c gunzip uncompression error
2855 -7 common/cmd_bootm.c Unimplemented compression type
2856 7 common/cmd_bootm.c Uncompression OK
2857 8 common/cmd_bootm.c No uncompress/copy overwrite error
2858 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2860 9 common/image.c Start initial ramdisk verification
2861 -10 common/image.c Ramdisk header has bad magic number
2862 -11 common/image.c Ramdisk header has bad checksum
2863 10 common/image.c Ramdisk header is OK
2864 -12 common/image.c Ramdisk data has bad checksum
2865 11 common/image.c Ramdisk data has correct checksum
2866 12 common/image.c Ramdisk verification complete, start loading
2867 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2868 13 common/image.c Start multifile image verification
2869 14 common/image.c No initial ramdisk, no multifile, continue.
2871 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2873 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2874 -31 post/post.c POST test failed, detected by post_output_backlog()
2875 -32 post/post.c POST test failed, detected by post_run_single()
2877 34 common/cmd_doc.c before loading a Image from a DOC device
2878 -35 common/cmd_doc.c Bad usage of "doc" command
2879 35 common/cmd_doc.c correct usage of "doc" command
2880 -36 common/cmd_doc.c No boot device
2881 36 common/cmd_doc.c correct boot device
2882 -37 common/cmd_doc.c Unknown Chip ID on boot device
2883 37 common/cmd_doc.c correct chip ID found, device available
2884 -38 common/cmd_doc.c Read Error on boot device
2885 38 common/cmd_doc.c reading Image header from DOC device OK
2886 -39 common/cmd_doc.c Image header has bad magic number
2887 39 common/cmd_doc.c Image header has correct magic number
2888 -40 common/cmd_doc.c Error reading Image from DOC device
2889 40 common/cmd_doc.c Image header has correct magic number
2890 41 common/cmd_ide.c before loading a Image from a IDE device
2891 -42 common/cmd_ide.c Bad usage of "ide" command
2892 42 common/cmd_ide.c correct usage of "ide" command
2893 -43 common/cmd_ide.c No boot device
2894 43 common/cmd_ide.c boot device found
2895 -44 common/cmd_ide.c Device not available
2896 44 common/cmd_ide.c Device available
2897 -45 common/cmd_ide.c wrong partition selected
2898 45 common/cmd_ide.c partition selected
2899 -46 common/cmd_ide.c Unknown partition table
2900 46 common/cmd_ide.c valid partition table found
2901 -47 common/cmd_ide.c Invalid partition type
2902 47 common/cmd_ide.c correct partition type
2903 -48 common/cmd_ide.c Error reading Image Header on boot device
2904 48 common/cmd_ide.c reading Image Header from IDE device OK
2905 -49 common/cmd_ide.c Image header has bad magic number
2906 49 common/cmd_ide.c Image header has correct magic number
2907 -50 common/cmd_ide.c Image header has bad checksum
2908 50 common/cmd_ide.c Image header has correct checksum
2909 -51 common/cmd_ide.c Error reading Image from IDE device
2910 51 common/cmd_ide.c reading Image from IDE device OK
2911 52 common/cmd_nand.c before loading a Image from a NAND device
2912 -53 common/cmd_nand.c Bad usage of "nand" command
2913 53 common/cmd_nand.c correct usage of "nand" command
2914 -54 common/cmd_nand.c No boot device
2915 54 common/cmd_nand.c boot device found
2916 -55 common/cmd_nand.c Unknown Chip ID on boot device
2917 55 common/cmd_nand.c correct chip ID found, device available
2918 -56 common/cmd_nand.c Error reading Image Header on boot device
2919 56 common/cmd_nand.c reading Image Header from NAND device OK
2920 -57 common/cmd_nand.c Image header has bad magic number
2921 57 common/cmd_nand.c Image header has correct magic number
2922 -58 common/cmd_nand.c Error reading Image from NAND device
2923 58 common/cmd_nand.c reading Image from NAND device OK
2925 -60 common/env_common.c Environment has a bad CRC, using default
2927 64 net/eth.c starting with Ethernet configuration.
2928 -64 net/eth.c no Ethernet found.
2929 65 net/eth.c Ethernet found.
2931 -80 common/cmd_net.c usage wrong
2932 80 common/cmd_net.c before calling net_loop()
2933 -81 common/cmd_net.c some error in net_loop() occurred
2934 81 common/cmd_net.c net_loop() back without error
2935 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2936 82 common/cmd_net.c trying automatic boot
2937 83 common/cmd_net.c running "source" command
2938 -83 common/cmd_net.c some error in automatic boot or "source" command
2939 84 common/cmd_net.c end without errors
2944 100 common/cmd_bootm.c Kernel FIT Image has correct format
2945 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2946 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2947 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2948 102 common/cmd_bootm.c Kernel unit name specified
2949 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2950 103 common/cmd_bootm.c Found configuration node
2951 104 common/cmd_bootm.c Got kernel subimage node offset
2952 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2953 105 common/cmd_bootm.c Kernel subimage hash verification OK
2954 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2955 106 common/cmd_bootm.c Architecture check OK
2956 -106 common/cmd_bootm.c Kernel subimage has wrong type
2957 107 common/cmd_bootm.c Kernel subimage type OK
2958 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2959 108 common/cmd_bootm.c Got kernel subimage data/size
2960 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2961 -109 common/cmd_bootm.c Can't get kernel subimage type
2962 -110 common/cmd_bootm.c Can't get kernel subimage comp
2963 -111 common/cmd_bootm.c Can't get kernel subimage os
2964 -112 common/cmd_bootm.c Can't get kernel subimage load address
2965 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2967 120 common/image.c Start initial ramdisk verification
2968 -120 common/image.c Ramdisk FIT image has incorrect format
2969 121 common/image.c Ramdisk FIT image has correct format
2970 122 common/image.c No ramdisk subimage unit name, using configuration
2971 -122 common/image.c Can't get configuration for ramdisk subimage
2972 123 common/image.c Ramdisk unit name specified
2973 -124 common/image.c Can't get ramdisk subimage node offset
2974 125 common/image.c Got ramdisk subimage node offset
2975 -125 common/image.c Ramdisk subimage hash verification failed
2976 126 common/image.c Ramdisk subimage hash verification OK
2977 -126 common/image.c Ramdisk subimage for unsupported architecture
2978 127 common/image.c Architecture check OK
2979 -127 common/image.c Can't get ramdisk subimage data/size
2980 128 common/image.c Got ramdisk subimage data/size
2981 129 common/image.c Can't get ramdisk load address
2982 -129 common/image.c Got ramdisk load address
2984 -130 common/cmd_doc.c Incorrect FIT image format
2985 131 common/cmd_doc.c FIT image format OK
2987 -140 common/cmd_ide.c Incorrect FIT image format
2988 141 common/cmd_ide.c FIT image format OK
2990 -150 common/cmd_nand.c Incorrect FIT image format
2991 151 common/cmd_nand.c FIT image format OK
2993 - legacy image format:
2994 CONFIG_IMAGE_FORMAT_LEGACY
2995 enables the legacy image format support in U-Boot.
2998 enabled if CONFIG_FIT_SIGNATURE is not defined.
3000 CONFIG_DISABLE_IMAGE_LEGACY
3001 disable the legacy image format
3003 This define is introduced, as the legacy image format is
3004 enabled per default for backward compatibility.
3006 - FIT image support:
3007 CONFIG_FIT_DISABLE_SHA256
3008 Supporting SHA256 hashes has quite an impact on binary size.
3009 For constrained systems sha256 hash support can be disabled
3012 TODO(sjg@chromium.org): Adjust this option to be positive,
3013 and move it to Kconfig
3015 - Standalone program support:
3016 CONFIG_STANDALONE_LOAD_ADDR
3018 This option defines a board specific value for the
3019 address where standalone program gets loaded, thus
3020 overwriting the architecture dependent default
3023 - Frame Buffer Address:
3026 Define CONFIG_FB_ADDR if you want to use specific
3027 address for frame buffer. This is typically the case
3028 when using a graphics controller has separate video
3029 memory. U-Boot will then place the frame buffer at
3030 the given address instead of dynamically reserving it
3031 in system RAM by calling lcd_setmem(), which grabs
3032 the memory for the frame buffer depending on the
3033 configured panel size.
3035 Please see board_init_f function.
3037 - Automatic software updates via TFTP server
3039 CONFIG_UPDATE_TFTP_CNT_MAX
3040 CONFIG_UPDATE_TFTP_MSEC_MAX
3042 These options enable and control the auto-update feature;
3043 for a more detailed description refer to doc/README.update.
3045 - MTD Support (mtdparts command, UBI support)
3048 Adds the MTD device infrastructure from the Linux kernel.
3049 Needed for mtdparts command support.
3051 CONFIG_MTD_PARTITIONS
3053 Adds the MTD partitioning infrastructure from the Linux
3054 kernel. Needed for UBI support.
3059 Adds commands for interacting with MTD partitions formatted
3060 with the UBI flash translation layer
3062 Requires also defining CONFIG_RBTREE
3064 CONFIG_UBI_SILENCE_MSG
3066 Make the verbose messages from UBI stop printing. This leaves
3067 warnings and errors enabled.
3070 CONFIG_MTD_UBI_WL_THRESHOLD
3071 This parameter defines the maximum difference between the highest
3072 erase counter value and the lowest erase counter value of eraseblocks
3073 of UBI devices. When this threshold is exceeded, UBI starts performing
3074 wear leveling by means of moving data from eraseblock with low erase
3075 counter to eraseblocks with high erase counter.
3077 The default value should be OK for SLC NAND flashes, NOR flashes and
3078 other flashes which have eraseblock life-cycle 100000 or more.
3079 However, in case of MLC NAND flashes which typically have eraseblock
3080 life-cycle less than 10000, the threshold should be lessened (e.g.,
3081 to 128 or 256, although it does not have to be power of 2).
3085 CONFIG_MTD_UBI_BEB_LIMIT
3086 This option specifies the maximum bad physical eraseblocks UBI
3087 expects on the MTD device (per 1024 eraseblocks). If the
3088 underlying flash does not admit of bad eraseblocks (e.g. NOR
3089 flash), this value is ignored.
3091 NAND datasheets often specify the minimum and maximum NVM
3092 (Number of Valid Blocks) for the flashes' endurance lifetime.
3093 The maximum expected bad eraseblocks per 1024 eraseblocks
3094 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3095 which gives 20 for most NANDs (MaxNVB is basically the total
3096 count of eraseblocks on the chip).
3098 To put it differently, if this value is 20, UBI will try to
3099 reserve about 1.9% of physical eraseblocks for bad blocks
3100 handling. And that will be 1.9% of eraseblocks on the entire
3101 NAND chip, not just the MTD partition UBI attaches. This means
3102 that if you have, say, a NAND flash chip admits maximum 40 bad
3103 eraseblocks, and it is split on two MTD partitions of the same
3104 size, UBI will reserve 40 eraseblocks when attaching a
3109 CONFIG_MTD_UBI_FASTMAP
3110 Fastmap is a mechanism which allows attaching an UBI device
3111 in nearly constant time. Instead of scanning the whole MTD device it
3112 only has to locate a checkpoint (called fastmap) on the device.
3113 The on-flash fastmap contains all information needed to attach
3114 the device. Using fastmap makes only sense on large devices where
3115 attaching by scanning takes long. UBI will not automatically install
3116 a fastmap on old images, but you can set the UBI parameter
3117 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3118 that fastmap-enabled images are still usable with UBI implementations
3119 without fastmap support. On typical flash devices the whole fastmap
3120 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3122 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3123 Set this parameter to enable fastmap automatically on images
3127 CONFIG_MTD_UBI_FM_DEBUG
3128 Enable UBI fastmap debug
3134 Adds commands for interacting with UBI volumes formatted as
3135 UBIFS. UBIFS is read-only in u-boot.
3137 Requires UBI support as well as CONFIG_LZO
3139 CONFIG_UBIFS_SILENCE_MSG
3141 Make the verbose messages from UBIFS stop printing. This leaves
3142 warnings and errors enabled.
3146 Enable building of SPL globally.
3149 LDSCRIPT for linking the SPL binary.
3151 CONFIG_SPL_MAX_FOOTPRINT
3152 Maximum size in memory allocated to the SPL, BSS included.
3153 When defined, the linker checks that the actual memory
3154 used by SPL from _start to __bss_end does not exceed it.
3155 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3156 must not be both defined at the same time.
3159 Maximum size of the SPL image (text, data, rodata, and
3160 linker lists sections), BSS excluded.
3161 When defined, the linker checks that the actual size does
3164 CONFIG_SPL_TEXT_BASE
3165 TEXT_BASE for linking the SPL binary.
3167 CONFIG_SPL_RELOC_TEXT_BASE
3168 Address to relocate to. If unspecified, this is equal to
3169 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3171 CONFIG_SPL_BSS_START_ADDR
3172 Link address for the BSS within the SPL binary.
3174 CONFIG_SPL_BSS_MAX_SIZE
3175 Maximum size in memory allocated to the SPL BSS.
3176 When defined, the linker checks that the actual memory used
3177 by SPL from __bss_start to __bss_end does not exceed it.
3178 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3179 must not be both defined at the same time.
3182 Adress of the start of the stack SPL will use
3184 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3185 When defined, SPL will panic() if the image it has
3186 loaded does not have a signature.
3187 Defining this is useful when code which loads images
3188 in SPL cannot guarantee that absolutely all read errors
3190 An example is the LPC32XX MLC NAND driver, which will
3191 consider that a completely unreadable NAND block is bad,
3192 and thus should be skipped silently.
3194 CONFIG_SPL_RELOC_STACK
3195 Adress of the start of the stack SPL will use after
3196 relocation. If unspecified, this is equal to
3199 CONFIG_SYS_SPL_MALLOC_START
3200 Starting address of the malloc pool used in SPL.
3201 When this option is set the full malloc is used in SPL and
3202 it is set up by spl_init() and before that, the simple malloc()
3203 can be used if CONFIG_SYS_MALLOC_F is defined.
3205 CONFIG_SYS_SPL_MALLOC_SIZE
3206 The size of the malloc pool used in SPL.
3208 CONFIG_SPL_FRAMEWORK
3209 Enable the SPL framework under common/. This framework
3210 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3211 NAND loading of the Linux Kernel.
3214 Enable booting directly to an OS from SPL.
3215 See also: doc/README.falcon
3217 CONFIG_SPL_DISPLAY_PRINT
3218 For ARM, enable an optional function to print more information
3219 about the running system.
3221 CONFIG_SPL_INIT_MINIMAL
3222 Arch init code should be built for a very small image
3224 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3225 Partition on the MMC to load U-Boot from when the MMC is being
3228 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3229 Sector to load kernel uImage from when MMC is being
3230 used in raw mode (for Falcon mode)
3232 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3233 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3234 Sector and number of sectors to load kernel argument
3235 parameters from when MMC is being used in raw mode
3238 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3239 Partition on the MMC to load U-Boot from when the MMC is being
3242 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3243 Filename to read to load U-Boot when reading from filesystem
3245 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3246 Filename to read to load kernel uImage when reading
3247 from filesystem (for Falcon mode)
3249 CONFIG_SPL_FS_LOAD_ARGS_NAME
3250 Filename to read to load kernel argument parameters
3251 when reading from filesystem (for Falcon mode)
3253 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3254 Set this for NAND SPL on PPC mpc83xx targets, so that
3255 start.S waits for the rest of the SPL to load before
3256 continuing (the hardware starts execution after just
3257 loading the first page rather than the full 4K).
3259 CONFIG_SPL_SKIP_RELOCATE
3260 Avoid SPL relocation
3262 CONFIG_SPL_NAND_BASE
3263 Include nand_base.c in the SPL. Requires
3264 CONFIG_SPL_NAND_DRIVERS.
3266 CONFIG_SPL_NAND_DRIVERS
3267 SPL uses normal NAND drivers, not minimal drivers.
3270 Include standard software ECC in the SPL
3272 CONFIG_SPL_NAND_SIMPLE
3273 Support for NAND boot using simple NAND drivers that
3274 expose the cmd_ctrl() interface.
3277 Support for a lightweight UBI (fastmap) scanner and
3280 CONFIG_SPL_NAND_RAW_ONLY
3281 Support to boot only raw u-boot.bin images. Use this only
3282 if you need to save space.
3284 CONFIG_SPL_COMMON_INIT_DDR
3285 Set for common ddr init with serial presence detect in
3288 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3289 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3290 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3291 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3292 CONFIG_SYS_NAND_ECCBYTES
3293 Defines the size and behavior of the NAND that SPL uses
3296 CONFIG_SPL_NAND_BOOT
3297 Add support NAND boot
3299 CONFIG_SYS_NAND_U_BOOT_OFFS
3300 Location in NAND to read U-Boot from
3302 CONFIG_SYS_NAND_U_BOOT_DST
3303 Location in memory to load U-Boot to
3305 CONFIG_SYS_NAND_U_BOOT_SIZE
3306 Size of image to load
3308 CONFIG_SYS_NAND_U_BOOT_START
3309 Entry point in loaded image to jump to
3311 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3312 Define this if you need to first read the OOB and then the
3313 data. This is used, for example, on davinci platforms.
3315 CONFIG_SPL_OMAP3_ID_NAND
3316 Support for an OMAP3-specific set of functions to return the
3317 ID and MFR of the first attached NAND chip, if present.
3319 CONFIG_SPL_RAM_DEVICE
3320 Support for running image already present in ram, in SPL binary
3323 Image offset to which the SPL should be padded before appending
3324 the SPL payload. By default, this is defined as
3325 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3326 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3327 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3330 Final target image containing SPL and payload. Some SPLs
3331 use an arch-specific makefile fragment instead, for
3332 example if more than one image needs to be produced.
3334 CONFIG_FIT_SPL_PRINT
3335 Printing information about a FIT image adds quite a bit of
3336 code to SPL. So this is normally disabled in SPL. Use this
3337 option to re-enable it. This will affect the output of the
3338 bootm command when booting a FIT image.
3342 Enable building of TPL globally.
3345 Image offset to which the TPL should be padded before appending
3346 the TPL payload. By default, this is defined as
3347 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3348 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3349 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3351 - Interrupt support (PPC):
3353 There are common interrupt_init() and timer_interrupt()
3354 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3355 for CPU specific initialization. interrupt_init_cpu()
3356 should set decrementer_count to appropriate value. If
3357 CPU resets decrementer automatically after interrupt
3358 (ppc4xx) it should set decrementer_count to zero.
3359 timer_interrupt() calls timer_interrupt_cpu() for CPU
3360 specific handling. If board has watchdog / status_led
3361 / other_activity_monitor it works automatically from
3362 general timer_interrupt().
3365 Board initialization settings:
3366 ------------------------------
3368 During Initialization u-boot calls a number of board specific functions
3369 to allow the preparation of board specific prerequisites, e.g. pin setup
3370 before drivers are initialized. To enable these callbacks the
3371 following configuration macros have to be defined. Currently this is
3372 architecture specific, so please check arch/your_architecture/lib/board.c
3373 typically in board_init_f() and board_init_r().
3375 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3376 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3377 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3378 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3380 Configuration Settings:
3381 -----------------------
3383 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3384 Optionally it can be defined to support 64-bit memory commands.
3386 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3387 undefine this when you're short of memory.
3389 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3390 width of the commands listed in the 'help' command output.
3392 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3393 prompt for user input.
3395 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3397 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3399 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3401 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3402 the application (usually a Linux kernel) when it is
3405 - CONFIG_SYS_BAUDRATE_TABLE:
3406 List of legal baudrate settings for this board.
3408 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3409 Begin and End addresses of the area used by the
3412 - CONFIG_SYS_ALT_MEMTEST:
3413 Enable an alternate, more extensive memory test.
3415 - CONFIG_SYS_MEMTEST_SCRATCH:
3416 Scratch address used by the alternate memory test
3417 You only need to set this if address zero isn't writeable
3419 - CONFIG_SYS_MEM_RESERVE_SECURE
3420 Only implemented for ARMv8 for now.
3421 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3422 is substracted from total RAM and won't be reported to OS.
3423 This memory can be used as secure memory. A variable
3424 gd->arch.secure_ram is used to track the location. In systems
3425 the RAM base is not zero, or RAM is divided into banks,
3426 this variable needs to be recalcuated to get the address.
3428 - CONFIG_SYS_MEM_TOP_HIDE:
3429 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3430 this specified memory area will get subtracted from the top
3431 (end) of RAM and won't get "touched" at all by U-Boot. By
3432 fixing up gd->ram_size the Linux kernel should gets passed
3433 the now "corrected" memory size and won't touch it either.
3434 This should work for arch/ppc and arch/powerpc. Only Linux
3435 board ports in arch/powerpc with bootwrapper support that
3436 recalculate the memory size from the SDRAM controller setup
3437 will have to get fixed in Linux additionally.
3439 This option can be used as a workaround for the 440EPx/GRx
3440 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3443 WARNING: Please make sure that this value is a multiple of
3444 the Linux page size (normally 4k). If this is not the case,
3445 then the end address of the Linux memory will be located at a
3446 non page size aligned address and this could cause major
3449 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3450 Enable temporary baudrate change while serial download
3452 - CONFIG_SYS_SDRAM_BASE:
3453 Physical start address of SDRAM. _Must_ be 0 here.
3455 - CONFIG_SYS_FLASH_BASE:
3456 Physical start address of Flash memory.
3458 - CONFIG_SYS_MONITOR_BASE:
3459 Physical start address of boot monitor code (set by
3460 make config files to be same as the text base address
3461 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3462 CONFIG_SYS_FLASH_BASE when booting from flash.
3464 - CONFIG_SYS_MONITOR_LEN:
3465 Size of memory reserved for monitor code, used to
3466 determine _at_compile_time_ (!) if the environment is
3467 embedded within the U-Boot image, or in a separate
3470 - CONFIG_SYS_MALLOC_LEN:
3471 Size of DRAM reserved for malloc() use.
3473 - CONFIG_SYS_MALLOC_F_LEN
3474 Size of the malloc() pool for use before relocation. If
3475 this is defined, then a very simple malloc() implementation
3476 will become available before relocation. The address is just
3477 below the global data, and the stack is moved down to make
3480 This feature allocates regions with increasing addresses
3481 within the region. calloc() is supported, but realloc()
3482 is not available. free() is supported but does nothing.
3483 The memory will be freed (or in fact just forgotten) when
3484 U-Boot relocates itself.
3486 - CONFIG_SYS_MALLOC_SIMPLE
3487 Provides a simple and small malloc() and calloc() for those
3488 boards which do not use the full malloc in SPL (which is
3489 enabled with CONFIG_SYS_SPL_MALLOC_START).
3491 - CONFIG_SYS_NONCACHED_MEMORY:
3492 Size of non-cached memory area. This area of memory will be
3493 typically located right below the malloc() area and mapped
3494 uncached in the MMU. This is useful for drivers that would
3495 otherwise require a lot of explicit cache maintenance. For
3496 some drivers it's also impossible to properly maintain the
3497 cache. For example if the regions that need to be flushed
3498 are not a multiple of the cache-line size, *and* padding
3499 cannot be allocated between the regions to align them (i.e.
3500 if the HW requires a contiguous array of regions, and the
3501 size of each region is not cache-aligned), then a flush of
3502 one region may result in overwriting data that hardware has
3503 written to another region in the same cache-line. This can
3504 happen for example in network drivers where descriptors for
3505 buffers are typically smaller than the CPU cache-line (e.g.
3506 16 bytes vs. 32 or 64 bytes).
3508 Non-cached memory is only supported on 32-bit ARM at present.
3510 - CONFIG_SYS_BOOTM_LEN:
3511 Normally compressed uImages are limited to an
3512 uncompressed size of 8 MBytes. If this is not enough,
3513 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3514 to adjust this setting to your needs.
3516 - CONFIG_SYS_BOOTMAPSZ:
3517 Maximum size of memory mapped by the startup code of
3518 the Linux kernel; all data that must be processed by
3519 the Linux kernel (bd_info, boot arguments, FDT blob if
3520 used) must be put below this limit, unless "bootm_low"
3521 environment variable is defined and non-zero. In such case
3522 all data for the Linux kernel must be between "bootm_low"
3523 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3524 variable "bootm_mapsize" will override the value of
3525 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3526 then the value in "bootm_size" will be used instead.
3528 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3529 Enable initrd_high functionality. If defined then the
3530 initrd_high feature is enabled and the bootm ramdisk subcommand
3533 - CONFIG_SYS_BOOT_GET_CMDLINE:
3534 Enables allocating and saving kernel cmdline in space between
3535 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3537 - CONFIG_SYS_BOOT_GET_KBD:
3538 Enables allocating and saving a kernel copy of the bd_info in
3539 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3541 - CONFIG_SYS_MAX_FLASH_BANKS:
3542 Max number of Flash memory banks
3544 - CONFIG_SYS_MAX_FLASH_SECT:
3545 Max number of sectors on a Flash chip
3547 - CONFIG_SYS_FLASH_ERASE_TOUT:
3548 Timeout for Flash erase operations (in ms)
3550 - CONFIG_SYS_FLASH_WRITE_TOUT:
3551 Timeout for Flash write operations (in ms)
3553 - CONFIG_SYS_FLASH_LOCK_TOUT
3554 Timeout for Flash set sector lock bit operation (in ms)
3556 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3557 Timeout for Flash clear lock bits operation (in ms)
3559 - CONFIG_SYS_FLASH_PROTECTION
3560 If defined, hardware flash sectors protection is used
3561 instead of U-Boot software protection.
3563 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3565 Enable TFTP transfers directly to flash memory;
3566 without this option such a download has to be
3567 performed in two steps: (1) download to RAM, and (2)
3568 copy from RAM to flash.
3570 The two-step approach is usually more reliable, since
3571 you can check if the download worked before you erase
3572 the flash, but in some situations (when system RAM is
3573 too limited to allow for a temporary copy of the
3574 downloaded image) this option may be very useful.
3576 - CONFIG_SYS_FLASH_CFI:
3577 Define if the flash driver uses extra elements in the
3578 common flash structure for storing flash geometry.
3580 - CONFIG_FLASH_CFI_DRIVER
3581 This option also enables the building of the cfi_flash driver
3582 in the drivers directory
3584 - CONFIG_FLASH_CFI_MTD
3585 This option enables the building of the cfi_mtd driver
3586 in the drivers directory. The driver exports CFI flash
3589 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3590 Use buffered writes to flash.
3592 - CONFIG_FLASH_SPANSION_S29WS_N
3593 s29ws-n MirrorBit flash has non-standard addresses for buffered
3596 - CONFIG_SYS_FLASH_QUIET_TEST
3597 If this option is defined, the common CFI flash doesn't
3598 print it's warning upon not recognized FLASH banks. This
3599 is useful, if some of the configured banks are only
3600 optionally available.
3602 - CONFIG_FLASH_SHOW_PROGRESS
3603 If defined (must be an integer), print out countdown
3604 digits and dots. Recommended value: 45 (9..1) for 80
3605 column displays, 15 (3..1) for 40 column displays.
3607 - CONFIG_FLASH_VERIFY
3608 If defined, the content of the flash (destination) is compared
3609 against the source after the write operation. An error message
3610 will be printed when the contents are not identical.
3611 Please note that this option is useless in nearly all cases,
3612 since such flash programming errors usually are detected earlier
3613 while unprotecting/erasing/programming. Please only enable
3614 this option if you really know what you are doing.
3616 - CONFIG_SYS_RX_ETH_BUFFER:
3617 Defines the number of Ethernet receive buffers. On some
3618 Ethernet controllers it is recommended to set this value
3619 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3620 buffers can be full shortly after enabling the interface
3621 on high Ethernet traffic.
3622 Defaults to 4 if not defined.
3624 - CONFIG_ENV_MAX_ENTRIES
3626 Maximum number of entries in the hash table that is used
3627 internally to store the environment settings. The default
3628 setting is supposed to be generous and should work in most
3629 cases. This setting can be used to tune behaviour; see
3630 lib/hashtable.c for details.
3632 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3633 - CONFIG_ENV_FLAGS_LIST_STATIC
3634 Enable validation of the values given to environment variables when
3635 calling env set. Variables can be restricted to only decimal,
3636 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3637 the variables can also be restricted to IP address or MAC address.
3639 The format of the list is:
3640 type_attribute = [s|d|x|b|i|m]
3641 access_attribute = [a|r|o|c]
3642 attributes = type_attribute[access_attribute]
3643 entry = variable_name[:attributes]
3646 The type attributes are:
3647 s - String (default)
3650 b - Boolean ([1yYtT|0nNfF])
3654 The access attributes are:
3660 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3661 Define this to a list (string) to define the ".flags"
3662 environment variable in the default or embedded environment.
3664 - CONFIG_ENV_FLAGS_LIST_STATIC
3665 Define this to a list (string) to define validation that
3666 should be done if an entry is not found in the ".flags"
3667 environment variable. To override a setting in the static
3668 list, simply add an entry for the same variable name to the
3671 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3672 regular expression. This allows multiple variables to define the same
3673 flags without explicitly listing them for each variable.
3675 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3676 If defined, don't allow the -f switch to env set override variable
3679 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3680 This is set by OMAP boards for the max time that reset should
3681 be asserted. See doc/README.omap-reset-time for details on how
3682 the value can be calculated on a given board.
3685 If stdint.h is available with your toolchain you can define this
3686 option to enable it. You can provide option 'USE_STDINT=1' when
3687 building U-Boot to enable this.
3689 The following definitions that deal with the placement and management
3690 of environment data (variable area); in general, we support the
3691 following configurations:
3693 - CONFIG_BUILD_ENVCRC:
3695 Builds up envcrc with the target environment so that external utils
3696 may easily extract it and embed it in final U-Boot images.
3698 - CONFIG_ENV_IS_IN_FLASH:
3700 Define this if the environment is in flash memory.
3702 a) The environment occupies one whole flash sector, which is
3703 "embedded" in the text segment with the U-Boot code. This
3704 happens usually with "bottom boot sector" or "top boot
3705 sector" type flash chips, which have several smaller
3706 sectors at the start or the end. For instance, such a
3707 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3708 such a case you would place the environment in one of the
3709 4 kB sectors - with U-Boot code before and after it. With
3710 "top boot sector" type flash chips, you would put the
3711 environment in one of the last sectors, leaving a gap
3712 between U-Boot and the environment.
3714 - CONFIG_ENV_OFFSET:
3716 Offset of environment data (variable area) to the
3717 beginning of flash memory; for instance, with bottom boot
3718 type flash chips the second sector can be used: the offset
3719 for this sector is given here.
3721 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3725 This is just another way to specify the start address of
3726 the flash sector containing the environment (instead of
3729 - CONFIG_ENV_SECT_SIZE:
3731 Size of the sector containing the environment.
3734 b) Sometimes flash chips have few, equal sized, BIG sectors.
3735 In such a case you don't want to spend a whole sector for
3740 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3741 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3742 of this flash sector for the environment. This saves
3743 memory for the RAM copy of the environment.
3745 It may also save flash memory if you decide to use this
3746 when your environment is "embedded" within U-Boot code,
3747 since then the remainder of the flash sector could be used
3748 for U-Boot code. It should be pointed out that this is
3749 STRONGLY DISCOURAGED from a robustness point of view:
3750 updating the environment in flash makes it always
3751 necessary to erase the WHOLE sector. If something goes
3752 wrong before the contents has been restored from a copy in
3753 RAM, your target system will be dead.
3755 - CONFIG_ENV_ADDR_REDUND
3756 CONFIG_ENV_SIZE_REDUND
3758 These settings describe a second storage area used to hold
3759 a redundant copy of the environment data, so that there is
3760 a valid backup copy in case there is a power failure during
3761 a "saveenv" operation.
3763 BE CAREFUL! Any changes to the flash layout, and some changes to the
3764 source code will make it necessary to adapt <board>/u-boot.lds*
3768 - CONFIG_ENV_IS_IN_NVRAM:
3770 Define this if you have some non-volatile memory device
3771 (NVRAM, battery buffered SRAM) which you want to use for the
3777 These two #defines are used to determine the memory area you
3778 want to use for environment. It is assumed that this memory
3779 can just be read and written to, without any special
3782 BE CAREFUL! The first access to the environment happens quite early
3783 in U-Boot initialization (when we try to get the setting of for the
3784 console baudrate). You *MUST* have mapped your NVRAM area then, or
3787 Please note that even with NVRAM we still use a copy of the
3788 environment in RAM: we could work on NVRAM directly, but we want to
3789 keep settings there always unmodified except somebody uses "saveenv"
3790 to save the current settings.
3793 - CONFIG_ENV_IS_IN_EEPROM:
3795 Use this if you have an EEPROM or similar serial access
3796 device and a driver for it.
3798 - CONFIG_ENV_OFFSET:
3801 These two #defines specify the offset and size of the
3802 environment area within the total memory of your EEPROM.
3804 - CONFIG_SYS_I2C_EEPROM_ADDR:
3805 If defined, specified the chip address of the EEPROM device.
3806 The default address is zero.
3808 - CONFIG_SYS_I2C_EEPROM_BUS:
3809 If defined, specified the i2c bus of the EEPROM device.
3811 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3812 If defined, the number of bits used to address bytes in a
3813 single page in the EEPROM device. A 64 byte page, for example
3814 would require six bits.
3816 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3817 If defined, the number of milliseconds to delay between
3818 page writes. The default is zero milliseconds.
3820 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3821 The length in bytes of the EEPROM memory array address. Note
3822 that this is NOT the chip address length!
3824 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3825 EEPROM chips that implement "address overflow" are ones
3826 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3827 address and the extra bits end up in the "chip address" bit
3828 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3831 Note that we consider the length of the address field to
3832 still be one byte because the extra address bits are hidden
3833 in the chip address.
3835 - CONFIG_SYS_EEPROM_SIZE:
3836 The size in bytes of the EEPROM device.
3838 - CONFIG_ENV_EEPROM_IS_ON_I2C
3839 define this, if you have I2C and SPI activated, and your
3840 EEPROM, which holds the environment, is on the I2C bus.
3842 - CONFIG_I2C_ENV_EEPROM_BUS
3843 if you have an Environment on an EEPROM reached over
3844 I2C muxes, you can define here, how to reach this
3845 EEPROM. For example:
3847 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3849 EEPROM which holds the environment, is reached over
3850 a pca9547 i2c mux with address 0x70, channel 3.
3852 - CONFIG_ENV_IS_IN_DATAFLASH:
3854 Define this if you have a DataFlash memory device which you
3855 want to use for the environment.
3857 - CONFIG_ENV_OFFSET:
3861 These three #defines specify the offset and size of the
3862 environment area within the total memory of your DataFlash placed
3863 at the specified address.
3865 - CONFIG_ENV_IS_IN_SPI_FLASH:
3867 Define this if you have a SPI Flash memory device which you
3868 want to use for the environment.
3870 - CONFIG_ENV_OFFSET:
3873 These two #defines specify the offset and size of the
3874 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3875 aligned to an erase sector boundary.
3877 - CONFIG_ENV_SECT_SIZE:
3879 Define the SPI flash's sector size.
3881 - CONFIG_ENV_OFFSET_REDUND (optional):
3883 This setting describes a second storage area of CONFIG_ENV_SIZE
3884 size used to hold a redundant copy of the environment data, so
3885 that there is a valid backup copy in case there is a power failure
3886 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3887 aligned to an erase sector boundary.
3889 - CONFIG_ENV_SPI_BUS (optional):
3890 - CONFIG_ENV_SPI_CS (optional):
3892 Define the SPI bus and chip select. If not defined they will be 0.
3894 - CONFIG_ENV_SPI_MAX_HZ (optional):
3896 Define the SPI max work clock. If not defined then use 1MHz.
3898 - CONFIG_ENV_SPI_MODE (optional):
3900 Define the SPI work mode. If not defined then use SPI_MODE_3.
3902 - CONFIG_ENV_IS_IN_REMOTE:
3904 Define this if you have a remote memory space which you
3905 want to use for the local device's environment.
3910 These two #defines specify the address and size of the
3911 environment area within the remote memory space. The
3912 local device can get the environment from remote memory
3913 space by SRIO or PCIE links.
3915 BE CAREFUL! For some special cases, the local device can not use
3916 "saveenv" command. For example, the local device will get the
3917 environment stored in a remote NOR flash by SRIO or PCIE link,
3918 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3920 - CONFIG_ENV_IS_IN_NAND:
3922 Define this if you have a NAND device which you want to use
3923 for the environment.
3925 - CONFIG_ENV_OFFSET:
3928 These two #defines specify the offset and size of the environment
3929 area within the first NAND device. CONFIG_ENV_OFFSET must be
3930 aligned to an erase block boundary.
3932 - CONFIG_ENV_OFFSET_REDUND (optional):
3934 This setting describes a second storage area of CONFIG_ENV_SIZE
3935 size used to hold a redundant copy of the environment data, so
3936 that there is a valid backup copy in case there is a power failure
3937 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3938 aligned to an erase block boundary.
3940 - CONFIG_ENV_RANGE (optional):
3942 Specifies the length of the region in which the environment
3943 can be written. This should be a multiple of the NAND device's
3944 block size. Specifying a range with more erase blocks than
3945 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3946 the range to be avoided.
3948 - CONFIG_ENV_OFFSET_OOB (optional):
3950 Enables support for dynamically retrieving the offset of the
3951 environment from block zero's out-of-band data. The
3952 "nand env.oob" command can be used to record this offset.
3953 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3954 using CONFIG_ENV_OFFSET_OOB.
3956 - CONFIG_NAND_ENV_DST
3958 Defines address in RAM to which the nand_spl code should copy the
3959 environment. If redundant environment is used, it will be copied to
3960 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3962 - CONFIG_ENV_IS_IN_UBI:
3964 Define this if you have an UBI volume that you want to use for the
3965 environment. This has the benefit of wear-leveling the environment
3966 accesses, which is important on NAND.
3968 - CONFIG_ENV_UBI_PART:
3970 Define this to a string that is the mtd partition containing the UBI.
3972 - CONFIG_ENV_UBI_VOLUME:
3974 Define this to the name of the volume that you want to store the
3977 - CONFIG_ENV_UBI_VOLUME_REDUND:
3979 Define this to the name of another volume to store a second copy of
3980 the environment in. This will enable redundant environments in UBI.
3981 It is assumed that both volumes are in the same MTD partition.
3983 - CONFIG_UBI_SILENCE_MSG
3984 - CONFIG_UBIFS_SILENCE_MSG
3986 You will probably want to define these to avoid a really noisy system
3987 when storing the env in UBI.
3989 - CONFIG_ENV_IS_IN_FAT:
3990 Define this if you want to use the FAT file system for the environment.
3992 - FAT_ENV_INTERFACE:
3994 Define this to a string that is the name of the block device.
3996 - FAT_ENV_DEVICE_AND_PART:
3998 Define this to a string to specify the partition of the device. It can
4001 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4002 - "D:P": device D partition P. Error occurs if device D has no
4005 - "D" or "D:": device D partition 1 if device D has partition
4006 table, or the whole device D if has no partition
4008 - "D:auto": first partition in device D with bootable flag set.
4009 If none, first valid partition in device D. If no
4010 partition table then means device D.
4014 It's a string of the FAT file name. This file use to store the
4018 This should be defined. Otherwise it cannot save the environment file.
4020 - CONFIG_ENV_IS_IN_MMC:
4022 Define this if you have an MMC device which you want to use for the
4025 - CONFIG_SYS_MMC_ENV_DEV:
4027 Specifies which MMC device the environment is stored in.
4029 - CONFIG_SYS_MMC_ENV_PART (optional):
4031 Specifies which MMC partition the environment is stored in. If not
4032 set, defaults to partition 0, the user area. Common values might be
4033 1 (first MMC boot partition), 2 (second MMC boot partition).
4035 - CONFIG_ENV_OFFSET:
4038 These two #defines specify the offset and size of the environment
4039 area within the specified MMC device.
4041 If offset is positive (the usual case), it is treated as relative to
4042 the start of the MMC partition. If offset is negative, it is treated
4043 as relative to the end of the MMC partition. This can be useful if
4044 your board may be fitted with different MMC devices, which have
4045 different sizes for the MMC partitions, and you always want the
4046 environment placed at the very end of the partition, to leave the
4047 maximum possible space before it, to store other data.
4049 These two values are in units of bytes, but must be aligned to an
4050 MMC sector boundary.
4052 - CONFIG_ENV_OFFSET_REDUND (optional):
4054 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4055 hold a redundant copy of the environment data. This provides a
4056 valid backup copy in case the other copy is corrupted, e.g. due
4057 to a power failure during a "saveenv" operation.
4059 This value may also be positive or negative; this is handled in the
4060 same way as CONFIG_ENV_OFFSET.
4062 This value is also in units of bytes, but must also be aligned to
4063 an MMC sector boundary.
4065 - CONFIG_ENV_SIZE_REDUND (optional):
4067 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4068 set. If this value is set, it must be set to the same value as
4071 - CONFIG_SYS_SPI_INIT_OFFSET
4073 Defines offset to the initial SPI buffer area in DPRAM. The
4074 area is used at an early stage (ROM part) if the environment
4075 is configured to reside in the SPI EEPROM: We need a 520 byte
4076 scratch DPRAM area. It is used between the two initialization
4077 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4078 to be a good choice since it makes it far enough from the
4079 start of the data area as well as from the stack pointer.
4081 Please note that the environment is read-only until the monitor
4082 has been relocated to RAM and a RAM copy of the environment has been
4083 created; also, when using EEPROM you will have to use getenv_f()
4084 until then to read environment variables.
4086 The environment is protected by a CRC32 checksum. Before the monitor
4087 is relocated into RAM, as a result of a bad CRC you will be working
4088 with the compiled-in default environment - *silently*!!! [This is
4089 necessary, because the first environment variable we need is the
4090 "baudrate" setting for the console - if we have a bad CRC, we don't
4091 have any device yet where we could complain.]
4093 Note: once the monitor has been relocated, then it will complain if
4094 the default environment is used; a new CRC is computed as soon as you
4095 use the "saveenv" command to store a valid environment.
4097 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4098 Echo the inverted Ethernet link state to the fault LED.
4100 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4101 also needs to be defined.
4103 - CONFIG_SYS_FAULT_MII_ADDR:
4104 MII address of the PHY to check for the Ethernet link state.
4106 - CONFIG_NS16550_MIN_FUNCTIONS:
4107 Define this if you desire to only have use of the NS16550_init
4108 and NS16550_putc functions for the serial driver located at
4109 drivers/serial/ns16550.c. This option is useful for saving
4110 space for already greatly restricted images, including but not
4111 limited to NAND_SPL configurations.
4113 - CONFIG_DISPLAY_BOARDINFO
4114 Display information about the board that U-Boot is running on
4115 when U-Boot starts up. The board function checkboard() is called
4118 - CONFIG_DISPLAY_BOARDINFO_LATE
4119 Similar to the previous option, but display this information
4120 later, once stdio is running and output goes to the LCD, if
4123 - CONFIG_BOARD_SIZE_LIMIT:
4124 Maximum size of the U-Boot image. When defined, the
4125 build system checks that the actual size does not
4128 Low Level (hardware related) configuration options:
4129 ---------------------------------------------------
4131 - CONFIG_SYS_CACHELINE_SIZE:
4132 Cache Line Size of the CPU.
4134 - CONFIG_SYS_DEFAULT_IMMR:
4135 Default address of the IMMR after system reset.
4137 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4138 and RPXsuper) to be able to adjust the position of
4139 the IMMR register after a reset.
4141 - CONFIG_SYS_CCSRBAR_DEFAULT:
4142 Default (power-on reset) physical address of CCSR on Freescale
4145 - CONFIG_SYS_CCSRBAR:
4146 Virtual address of CCSR. On a 32-bit build, this is typically
4147 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4149 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4150 for cross-platform code that uses that macro instead.
4152 - CONFIG_SYS_CCSRBAR_PHYS:
4153 Physical address of CCSR. CCSR can be relocated to a new
4154 physical address, if desired. In this case, this macro should
4155 be set to that address. Otherwise, it should be set to the
4156 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4157 is typically relocated on 36-bit builds. It is recommended
4158 that this macro be defined via the _HIGH and _LOW macros:
4160 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4161 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4163 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4164 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4165 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4166 used in assembly code, so it must not contain typecasts or
4167 integer size suffixes (e.g. "ULL").
4169 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4170 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4171 used in assembly code, so it must not contain typecasts or
4172 integer size suffixes (e.g. "ULL").
4174 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4175 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4176 forced to a value that ensures that CCSR is not relocated.
4178 - Floppy Disk Support:
4179 CONFIG_SYS_FDC_DRIVE_NUMBER
4181 the default drive number (default value 0)
4183 CONFIG_SYS_ISA_IO_STRIDE
4185 defines the spacing between FDC chipset registers
4188 CONFIG_SYS_ISA_IO_OFFSET
4190 defines the offset of register from address. It
4191 depends on which part of the data bus is connected to
4192 the FDC chipset. (default value 0)
4194 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4195 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4198 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4199 fdc_hw_init() is called at the beginning of the FDC
4200 setup. fdc_hw_init() must be provided by the board
4201 source code. It is used to make hardware-dependent
4205 Most IDE controllers were designed to be connected with PCI
4206 interface. Only few of them were designed for AHB interface.
4207 When software is doing ATA command and data transfer to
4208 IDE devices through IDE-AHB controller, some additional
4209 registers accessing to these kind of IDE-AHB controller
4212 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4213 DO NOT CHANGE unless you know exactly what you're
4214 doing! (11-4) [MPC8xx/82xx systems only]
4216 - CONFIG_SYS_INIT_RAM_ADDR:
4218 Start address of memory area that can be used for
4219 initial data and stack; please note that this must be
4220 writable memory that is working WITHOUT special
4221 initialization, i. e. you CANNOT use normal RAM which
4222 will become available only after programming the
4223 memory controller and running certain initialization
4226 U-Boot uses the following memory types:
4227 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4228 - MPC824X: data cache
4229 - PPC4xx: data cache
4231 - CONFIG_SYS_GBL_DATA_OFFSET:
4233 Offset of the initial data structure in the memory
4234 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4235 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4236 data is located at the end of the available space
4237 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4238 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4239 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4240 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4243 On the MPC824X (or other systems that use the data
4244 cache for initial memory) the address chosen for
4245 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4246 point to an otherwise UNUSED address space between
4247 the top of RAM and the start of the PCI space.
4249 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4251 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4253 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4255 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4257 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4259 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4261 - CONFIG_SYS_OR_TIMING_SDRAM:
4264 - CONFIG_SYS_MAMR_PTA:
4265 periodic timer for refresh
4267 - CONFIG_SYS_DER: Debug Event Register (37-47)
4269 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4270 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4271 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4272 CONFIG_SYS_BR1_PRELIM:
4273 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4275 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4276 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4277 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4278 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4280 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4281 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4282 Machine Mode Register and Memory Periodic Timer
4283 Prescaler definitions (SDRAM timing)
4285 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4286 enable I2C microcode relocation patch (MPC8xx);
4287 define relocation offset in DPRAM [DSP2]
4289 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4290 enable SMC microcode relocation patch (MPC8xx);
4291 define relocation offset in DPRAM [SMC1]
4293 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4294 enable SPI microcode relocation patch (MPC8xx);
4295 define relocation offset in DPRAM [SCC4]
4297 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4298 Offset of the bootmode word in DPRAM used by post
4299 (Power On Self Tests). This definition overrides
4300 #define'd default value in commproc.h resp.
4303 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4304 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4305 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4306 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4307 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4308 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4309 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4310 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4311 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4313 - CONFIG_PCI_DISABLE_PCIE:
4314 Disable PCI-Express on systems where it is supported but not
4317 - CONFIG_PCI_ENUM_ONLY
4318 Only scan through and get the devices on the buses.
4319 Don't do any setup work, presumably because someone or
4320 something has already done it, and we don't need to do it
4321 a second time. Useful for platforms that are pre-booted
4322 by coreboot or similar.
4324 - CONFIG_PCI_INDIRECT_BRIDGE:
4325 Enable support for indirect PCI bridges.
4328 Chip has SRIO or not
4331 Board has SRIO 1 port available
4334 Board has SRIO 2 port available
4336 - CONFIG_SRIO_PCIE_BOOT_MASTER
4337 Board can support master function for Boot from SRIO and PCIE
4339 - CONFIG_SYS_SRIOn_MEM_VIRT:
4340 Virtual Address of SRIO port 'n' memory region
4342 - CONFIG_SYS_SRIOn_MEM_PHYS:
4343 Physical Address of SRIO port 'n' memory region
4345 - CONFIG_SYS_SRIOn_MEM_SIZE:
4346 Size of SRIO port 'n' memory region
4348 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4349 Defined to tell the NAND controller that the NAND chip is using
4351 Not all NAND drivers use this symbol.
4352 Example of drivers that use it:
4353 - drivers/mtd/nand/ndfc.c
4354 - drivers/mtd/nand/mxc_nand.c
4356 - CONFIG_SYS_NDFC_EBC0_CFG
4357 Sets the EBC0_CFG register for the NDFC. If not defined
4358 a default value will be used.
4361 Get DDR timing information from an I2C EEPROM. Common
4362 with pluggable memory modules such as SODIMMs
4365 I2C address of the SPD EEPROM
4367 - CONFIG_SYS_SPD_BUS_NUM
4368 If SPD EEPROM is on an I2C bus other than the first
4369 one, specify here. Note that the value must resolve
4370 to something your driver can deal with.
4372 - CONFIG_SYS_DDR_RAW_TIMING
4373 Get DDR timing information from other than SPD. Common with
4374 soldered DDR chips onboard without SPD. DDR raw timing
4375 parameters are extracted from datasheet and hard-coded into
4376 header files or board specific files.
4378 - CONFIG_FSL_DDR_INTERACTIVE
4379 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4381 - CONFIG_FSL_DDR_SYNC_REFRESH
4382 Enable sync of refresh for multiple controllers.
4384 - CONFIG_FSL_DDR_BIST
4385 Enable built-in memory test for Freescale DDR controllers.
4387 - CONFIG_SYS_83XX_DDR_USES_CS0
4388 Only for 83xx systems. If specified, then DDR should
4389 be configured using CS0 and CS1 instead of CS2 and CS3.
4391 - CONFIG_ETHER_ON_FEC[12]
4392 Define to enable FEC[12] on a 8xx series processor.
4394 - CONFIG_FEC[12]_PHY
4395 Define to the hardcoded PHY address which corresponds
4396 to the given FEC; i. e.
4397 #define CONFIG_FEC1_PHY 4
4398 means that the PHY with address 4 is connected to FEC1
4400 When set to -1, means to probe for first available.
4402 - CONFIG_FEC[12]_PHY_NORXERR
4403 The PHY does not have a RXERR line (RMII only).
4404 (so program the FEC to ignore it).
4407 Enable RMII mode for all FECs.
4408 Note that this is a global option, we can't
4409 have one FEC in standard MII mode and another in RMII mode.
4411 - CONFIG_CRC32_VERIFY
4412 Add a verify option to the crc32 command.
4415 => crc32 -v <address> <count> <crc32>
4417 Where address/count indicate a memory area
4418 and crc32 is the correct crc32 which the
4422 Add the "loopw" memory command. This only takes effect if
4423 the memory commands are activated globally (CONFIG_CMD_MEM).
4426 Add the "mdc" and "mwc" memory commands. These are cyclic
4431 This command will print 4 bytes (10,11,12,13) each 500 ms.
4433 => mwc.l 100 12345678 10
4434 This command will write 12345678 to address 100 all 10 ms.
4436 This only takes effect if the memory commands are activated
4437 globally (CONFIG_CMD_MEM).
4439 - CONFIG_SKIP_LOWLEVEL_INIT
4440 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4441 low level initializations (like setting up the memory
4442 controller) are omitted and/or U-Boot does not
4443 relocate itself into RAM.
4445 Normally this variable MUST NOT be defined. The only
4446 exception is when U-Boot is loaded (to RAM) by some
4447 other boot loader or by a debugger which performs
4448 these initializations itself.
4450 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4451 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4452 to be skipped. The normal CP15 init (such as enabling the
4453 instruction cache) is still performed.
4456 Modifies the behaviour of start.S when compiling a loader
4457 that is executed before the actual U-Boot. E.g. when
4458 compiling a NAND SPL.
4461 Modifies the behaviour of start.S when compiling a loader
4462 that is executed after the SPL and before the actual U-Boot.
4463 It is loaded by the SPL.
4465 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4466 Only for 85xx systems. If this variable is specified, the section
4467 .resetvec is not kept and the section .bootpg is placed in the
4468 previous 4k of the .text section.
4470 - CONFIG_ARCH_MAP_SYSMEM
4471 Generally U-Boot (and in particular the md command) uses
4472 effective address. It is therefore not necessary to regard
4473 U-Boot address as virtual addresses that need to be translated
4474 to physical addresses. However, sandbox requires this, since
4475 it maintains its own little RAM buffer which contains all
4476 addressable memory. This option causes some memory accesses
4477 to be mapped through map_sysmem() / unmap_sysmem().
4479 - CONFIG_X86_RESET_VECTOR
4480 If defined, the x86 reset vector code is included. This is not
4481 needed when U-Boot is running from Coreboot.
4483 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4484 Enables the RTC32K OSC on AM33xx based plattforms
4486 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4487 Option to disable subpage write in NAND driver
4488 driver that uses this:
4489 drivers/mtd/nand/davinci_nand.c
4491 Freescale QE/FMAN Firmware Support:
4492 -----------------------------------
4494 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4495 loading of "firmware", which is encoded in the QE firmware binary format.
4496 This firmware often needs to be loaded during U-Boot booting, so macros
4497 are used to identify the storage device (NOR flash, SPI, etc) and the address
4500 - CONFIG_SYS_FMAN_FW_ADDR
4501 The address in the storage device where the FMAN microcode is located. The
4502 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4505 - CONFIG_SYS_QE_FW_ADDR
4506 The address in the storage device where the QE microcode is located. The
4507 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4510 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4511 The maximum possible size of the firmware. The firmware binary format
4512 has a field that specifies the actual size of the firmware, but it
4513 might not be possible to read any part of the firmware unless some
4514 local storage is allocated to hold the entire firmware first.
4516 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4517 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4518 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4519 virtual address in NOR flash.
4521 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4522 Specifies that QE/FMAN firmware is located in NAND flash.
4523 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4525 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4526 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4527 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4529 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4530 Specifies that QE/FMAN firmware is located in the remote (master)
4531 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4532 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4533 window->master inbound window->master LAW->the ucode address in
4534 master's memory space.
4536 Freescale Layerscape Management Complex Firmware Support:
4537 ---------------------------------------------------------
4538 The Freescale Layerscape Management Complex (MC) supports the loading of
4540 This firmware often needs to be loaded during U-Boot booting, so macros
4541 are used to identify the storage device (NOR flash, SPI, etc) and the address
4544 - CONFIG_FSL_MC_ENET
4545 Enable the MC driver for Layerscape SoCs.
4547 Freescale Layerscape Debug Server Support:
4548 -------------------------------------------
4549 The Freescale Layerscape Debug Server Support supports the loading of
4550 "Debug Server firmware" and triggering SP boot-rom.
4551 This firmware often needs to be loaded during U-Boot booting.
4553 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4554 Define alignment of reserved memory MC requires
4559 In order to achieve reproducible builds, timestamps used in the U-Boot build
4560 process have to be set to a fixed value.
4562 This is done using the SOURCE_DATE_EPOCH environment variable.
4563 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4564 option for U-Boot or an environment variable in U-Boot.
4566 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4568 Building the Software:
4569 ======================
4571 Building U-Boot has been tested in several native build environments
4572 and in many different cross environments. Of course we cannot support
4573 all possibly existing versions of cross development tools in all
4574 (potentially obsolete) versions. In case of tool chain problems we
4575 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4576 which is extensively used to build and test U-Boot.
4578 If you are not using a native environment, it is assumed that you
4579 have GNU cross compiling tools available in your path. In this case,
4580 you must set the environment variable CROSS_COMPILE in your shell.
4581 Note that no changes to the Makefile or any other source files are
4582 necessary. For example using the ELDK on a 4xx CPU, please enter:
4584 $ CROSS_COMPILE=ppc_4xx-
4585 $ export CROSS_COMPILE
4587 Note: If you wish to generate Windows versions of the utilities in
4588 the tools directory you can use the MinGW toolchain
4589 (http://www.mingw.org). Set your HOST tools to the MinGW
4590 toolchain and execute 'make tools'. For example:
4592 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4594 Binaries such as tools/mkimage.exe will be created which can
4595 be executed on computers running Windows.
4597 U-Boot is intended to be simple to build. After installing the
4598 sources you must configure U-Boot for one specific board type. This
4603 where "NAME_defconfig" is the name of one of the existing configu-
4604 rations; see boards.cfg for supported names.
4606 Note: for some board special configuration names may exist; check if
4607 additional information is available from the board vendor; for
4608 instance, the TQM823L systems are available without (standard)
4609 or with LCD support. You can select such additional "features"
4610 when choosing the configuration, i. e.
4612 make TQM823L_defconfig
4613 - will configure for a plain TQM823L, i. e. no LCD support
4615 make TQM823L_LCD_defconfig
4616 - will configure for a TQM823L with U-Boot console on LCD
4621 Finally, type "make all", and you should get some working U-Boot
4622 images ready for download to / installation on your system:
4624 - "u-boot.bin" is a raw binary image
4625 - "u-boot" is an image in ELF binary format
4626 - "u-boot.srec" is in Motorola S-Record format
4628 By default the build is performed locally and the objects are saved
4629 in the source directory. One of the two methods can be used to change
4630 this behavior and build U-Boot to some external directory:
4632 1. Add O= to the make command line invocations:
4634 make O=/tmp/build distclean
4635 make O=/tmp/build NAME_defconfig
4636 make O=/tmp/build all
4638 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4640 export KBUILD_OUTPUT=/tmp/build
4645 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4649 Please be aware that the Makefiles assume you are using GNU make, so
4650 for instance on NetBSD you might need to use "gmake" instead of
4654 If the system board that you have is not listed, then you will need
4655 to port U-Boot to your hardware platform. To do this, follow these
4658 1. Create a new directory to hold your board specific code. Add any
4659 files you need. In your board directory, you will need at least
4660 the "Makefile" and a "<board>.c".
4661 2. Create a new configuration file "include/configs/<board>.h" for
4663 3. If you're porting U-Boot to a new CPU, then also create a new
4664 directory to hold your CPU specific code. Add any files you need.
4665 4. Run "make <board>_defconfig" with your new name.
4666 5. Type "make", and you should get a working "u-boot.srec" file
4667 to be installed on your target system.
4668 6. Debug and solve any problems that might arise.
4669 [Of course, this last step is much harder than it sounds.]
4672 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4673 ==============================================================
4675 If you have modified U-Boot sources (for instance added a new board
4676 or support for new devices, a new CPU, etc.) you are expected to
4677 provide feedback to the other developers. The feedback normally takes
4678 the form of a "patch", i. e. a context diff against a certain (latest
4679 official or latest in the git repository) version of U-Boot sources.
4681 But before you submit such a patch, please verify that your modifi-
4682 cation did not break existing code. At least make sure that *ALL* of
4683 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4684 just run the buildman script (tools/buildman/buildman), which will
4685 configure and build U-Boot for ALL supported system. Be warned, this
4686 will take a while. Please see the buildman README, or run 'buildman -H'
4690 See also "U-Boot Porting Guide" below.
4693 Monitor Commands - Overview:
4694 ============================
4696 go - start application at address 'addr'
4697 run - run commands in an environment variable
4698 bootm - boot application image from memory
4699 bootp - boot image via network using BootP/TFTP protocol
4700 bootz - boot zImage from memory
4701 tftpboot- boot image via network using TFTP protocol
4702 and env variables "ipaddr" and "serverip"
4703 (and eventually "gatewayip")
4704 tftpput - upload a file via network using TFTP protocol
4705 rarpboot- boot image via network using RARP/TFTP protocol
4706 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4707 loads - load S-Record file over serial line
4708 loadb - load binary file over serial line (kermit mode)
4710 mm - memory modify (auto-incrementing)
4711 nm - memory modify (constant address)
4712 mw - memory write (fill)
4714 cmp - memory compare
4715 crc32 - checksum calculation
4716 i2c - I2C sub-system
4717 sspi - SPI utility commands
4718 base - print or set address offset
4719 printenv- print environment variables
4720 setenv - set environment variables
4721 saveenv - save environment variables to persistent storage
4722 protect - enable or disable FLASH write protection
4723 erase - erase FLASH memory
4724 flinfo - print FLASH memory information
4725 nand - NAND memory operations (see doc/README.nand)
4726 bdinfo - print Board Info structure
4727 iminfo - print header information for application image
4728 coninfo - print console devices and informations
4729 ide - IDE sub-system
4730 loop - infinite loop on address range
4731 loopw - infinite write loop on address range
4732 mtest - simple RAM test
4733 icache - enable or disable instruction cache
4734 dcache - enable or disable data cache
4735 reset - Perform RESET of the CPU
4736 echo - echo args to console
4737 version - print monitor version
4738 help - print online help
4739 ? - alias for 'help'
4742 Monitor Commands - Detailed Description:
4743 ========================================
4747 For now: just type "help <command>".
4750 Environment Variables:
4751 ======================
4753 U-Boot supports user configuration using Environment Variables which
4754 can be made persistent by saving to Flash memory.
4756 Environment Variables are set using "setenv", printed using
4757 "printenv", and saved to Flash using "saveenv". Using "setenv"
4758 without a value can be used to delete a variable from the
4759 environment. As long as you don't save the environment you are
4760 working with an in-memory copy. In case the Flash area containing the
4761 environment is erased by accident, a default environment is provided.
4763 Some configuration options can be set using Environment Variables.
4765 List of environment variables (most likely not complete):
4767 baudrate - see CONFIG_BAUDRATE
4769 bootdelay - see CONFIG_BOOTDELAY
4771 bootcmd - see CONFIG_BOOTCOMMAND
4773 bootargs - Boot arguments when booting an RTOS image
4775 bootfile - Name of the image to load with TFTP
4777 bootm_low - Memory range available for image processing in the bootm
4778 command can be restricted. This variable is given as
4779 a hexadecimal number and defines lowest address allowed
4780 for use by the bootm command. See also "bootm_size"
4781 environment variable. Address defined by "bootm_low" is
4782 also the base of the initial memory mapping for the Linux
4783 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4786 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4787 This variable is given as a hexadecimal number and it
4788 defines the size of the memory region starting at base
4789 address bootm_low that is accessible by the Linux kernel
4790 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4791 as the default value if it is defined, and bootm_size is
4794 bootm_size - Memory range available for image processing in the bootm
4795 command can be restricted. This variable is given as
4796 a hexadecimal number and defines the size of the region
4797 allowed for use by the bootm command. See also "bootm_low"
4798 environment variable.
4800 updatefile - Location of the software update file on a TFTP server, used
4801 by the automatic software update feature. Please refer to
4802 documentation in doc/README.update for more details.
4804 autoload - if set to "no" (any string beginning with 'n'),
4805 "bootp" will just load perform a lookup of the
4806 configuration from the BOOTP server, but not try to
4807 load any image using TFTP
4809 autostart - if set to "yes", an image loaded using the "bootp",
4810 "rarpboot", "tftpboot" or "diskboot" commands will
4811 be automatically started (by internally calling
4814 If set to "no", a standalone image passed to the
4815 "bootm" command will be copied to the load address
4816 (and eventually uncompressed), but NOT be started.
4817 This can be used to load and uncompress arbitrary
4820 fdt_high - if set this restricts the maximum address that the
4821 flattened device tree will be copied into upon boot.
4822 For example, if you have a system with 1 GB memory
4823 at physical address 0x10000000, while Linux kernel
4824 only recognizes the first 704 MB as low memory, you
4825 may need to set fdt_high as 0x3C000000 to have the
4826 device tree blob be copied to the maximum address
4827 of the 704 MB low memory, so that Linux kernel can
4828 access it during the boot procedure.
4830 If this is set to the special value 0xFFFFFFFF then
4831 the fdt will not be copied at all on boot. For this
4832 to work it must reside in writable memory, have
4833 sufficient padding on the end of it for u-boot to
4834 add the information it needs into it, and the memory
4835 must be accessible by the kernel.
4837 fdtcontroladdr- if set this is the address of the control flattened
4838 device tree used by U-Boot when CONFIG_OF_CONTROL is
4841 i2cfast - (PPC405GP|PPC405EP only)
4842 if set to 'y' configures Linux I2C driver for fast
4843 mode (400kHZ). This environment variable is used in
4844 initialization code. So, for changes to be effective
4845 it must be saved and board must be reset.
4847 initrd_high - restrict positioning of initrd images:
4848 If this variable is not set, initrd images will be
4849 copied to the highest possible address in RAM; this
4850 is usually what you want since it allows for
4851 maximum initrd size. If for some reason you want to
4852 make sure that the initrd image is loaded below the
4853 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4854 variable to a value of "no" or "off" or "0".
4855 Alternatively, you can set it to a maximum upper
4856 address to use (U-Boot will still check that it
4857 does not overwrite the U-Boot stack and data).
4859 For instance, when you have a system with 16 MB
4860 RAM, and want to reserve 4 MB from use by Linux,
4861 you can do this by adding "mem=12M" to the value of
4862 the "bootargs" variable. However, now you must make
4863 sure that the initrd image is placed in the first
4864 12 MB as well - this can be done with
4866 setenv initrd_high 00c00000
4868 If you set initrd_high to 0xFFFFFFFF, this is an
4869 indication to U-Boot that all addresses are legal
4870 for the Linux kernel, including addresses in flash
4871 memory. In this case U-Boot will NOT COPY the
4872 ramdisk at all. This may be useful to reduce the
4873 boot time on your system, but requires that this
4874 feature is supported by your Linux kernel.
4876 ipaddr - IP address; needed for tftpboot command
4878 loadaddr - Default load address for commands like "bootp",
4879 "rarpboot", "tftpboot", "loadb" or "diskboot"
4881 loads_echo - see CONFIG_LOADS_ECHO
4883 serverip - TFTP server IP address; needed for tftpboot command
4885 bootretry - see CONFIG_BOOT_RETRY_TIME
4887 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4889 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4891 ethprime - controls which interface is used first.
4893 ethact - controls which interface is currently active.
4894 For example you can do the following
4896 => setenv ethact FEC
4897 => ping 192.168.0.1 # traffic sent on FEC
4898 => setenv ethact SCC
4899 => ping 10.0.0.1 # traffic sent on SCC
4901 ethrotate - When set to "no" U-Boot does not go through all
4902 available network interfaces.
4903 It just stays at the currently selected interface.
4905 netretry - When set to "no" each network operation will
4906 either succeed or fail without retrying.
4907 When set to "once" the network operation will
4908 fail when all the available network interfaces
4909 are tried once without success.
4910 Useful on scripts which control the retry operation
4913 npe_ucode - set load address for the NPE microcode
4915 silent_linux - If set then Linux will be told to boot silently, by
4916 changing the console to be empty. If "yes" it will be
4917 made silent. If "no" it will not be made silent. If
4918 unset, then it will be made silent if the U-Boot console
4921 tftpsrcp - If this is set, the value is used for TFTP's
4924 tftpdstp - If this is set, the value is used for TFTP's UDP
4925 destination port instead of the Well Know Port 69.
4927 tftpblocksize - Block size to use for TFTP transfers; if not set,
4928 we use the TFTP server's default block size
4930 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4931 seconds, minimum value is 1000 = 1 second). Defines
4932 when a packet is considered to be lost so it has to
4933 be retransmitted. The default is 5000 = 5 seconds.
4934 Lowering this value may make downloads succeed
4935 faster in networks with high packet loss rates or
4936 with unreliable TFTP servers.
4938 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4939 unit, minimum value = 0). Defines how many timeouts
4940 can happen during a single file transfer before that
4941 transfer is aborted. The default is 10, and 0 means
4942 'no timeouts allowed'. Increasing this value may help
4943 downloads succeed with high packet loss rates, or with
4944 unreliable TFTP servers or client hardware.
4946 vlan - When set to a value < 4095 the traffic over
4947 Ethernet is encapsulated/received over 802.1q
4950 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4951 Unsigned value, in milliseconds. If not set, the period will
4952 be either the default (28000), or a value based on
4953 CONFIG_NET_RETRY_COUNT, if defined. This value has
4954 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4956 The following image location variables contain the location of images
4957 used in booting. The "Image" column gives the role of the image and is
4958 not an environment variable name. The other columns are environment
4959 variable names. "File Name" gives the name of the file on a TFTP
4960 server, "RAM Address" gives the location in RAM the image will be
4961 loaded to, and "Flash Location" gives the image's address in NOR
4962 flash or offset in NAND flash.
4964 *Note* - these variables don't have to be defined for all boards, some
4965 boards currently use other variables for these purposes, and some
4966 boards use these variables for other purposes.
4968 Image File Name RAM Address Flash Location
4969 ----- --------- ----------- --------------
4970 u-boot u-boot u-boot_addr_r u-boot_addr
4971 Linux kernel bootfile kernel_addr_r kernel_addr
4972 device tree blob fdtfile fdt_addr_r fdt_addr
4973 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4975 The following environment variables may be used and automatically
4976 updated by the network boot commands ("bootp" and "rarpboot"),
4977 depending the information provided by your boot server:
4979 bootfile - see above
4980 dnsip - IP address of your Domain Name Server
4981 dnsip2 - IP address of your secondary Domain Name Server
4982 gatewayip - IP address of the Gateway (Router) to use
4983 hostname - Target hostname
4985 netmask - Subnet Mask
4986 rootpath - Pathname of the root filesystem on the NFS server
4987 serverip - see above
4990 There are two special Environment Variables:
4992 serial# - contains hardware identification information such
4993 as type string and/or serial number
4994 ethaddr - Ethernet address
4996 These variables can be set only once (usually during manufacturing of
4997 the board). U-Boot refuses to delete or overwrite these variables
4998 once they have been set once.
5001 Further special Environment Variables:
5003 ver - Contains the U-Boot version string as printed
5004 with the "version" command. This variable is
5005 readonly (see CONFIG_VERSION_VARIABLE).
5008 Please note that changes to some configuration parameters may take
5009 only effect after the next boot (yes, that's just like Windoze :-).
5012 Callback functions for environment variables:
5013 ---------------------------------------------
5015 For some environment variables, the behavior of u-boot needs to change
5016 when their values are changed. This functionality allows functions to
5017 be associated with arbitrary variables. On creation, overwrite, or
5018 deletion, the callback will provide the opportunity for some side
5019 effect to happen or for the change to be rejected.
5021 The callbacks are named and associated with a function using the
5022 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5024 These callbacks are associated with variables in one of two ways. The
5025 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5026 in the board configuration to a string that defines a list of
5027 associations. The list must be in the following format:
5029 entry = variable_name[:callback_name]
5032 If the callback name is not specified, then the callback is deleted.
5033 Spaces are also allowed anywhere in the list.
5035 Callbacks can also be associated by defining the ".callbacks" variable
5036 with the same list format above. Any association in ".callbacks" will
5037 override any association in the static list. You can define
5038 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5039 ".callbacks" environment variable in the default or embedded environment.
5041 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5042 regular expression. This allows multiple variables to be connected to
5043 the same callback without explicitly listing them all out.
5046 Command Line Parsing:
5047 =====================
5049 There are two different command line parsers available with U-Boot:
5050 the old "simple" one, and the much more powerful "hush" shell:
5052 Old, simple command line parser:
5053 --------------------------------
5055 - supports environment variables (through setenv / saveenv commands)
5056 - several commands on one line, separated by ';'
5057 - variable substitution using "... ${name} ..." syntax
5058 - special characters ('$', ';') can be escaped by prefixing with '\',
5060 setenv bootcmd bootm \${address}
5061 - You can also escape text by enclosing in single apostrophes, for example:
5062 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5067 - similar to Bourne shell, with control structures like
5068 if...then...else...fi, for...do...done; while...do...done,
5069 until...do...done, ...
5070 - supports environment ("global") variables (through setenv / saveenv
5071 commands) and local shell variables (through standard shell syntax
5072 "name=value"); only environment variables can be used with "run"
5078 (1) If a command line (or an environment variable executed by a "run"
5079 command) contains several commands separated by semicolon, and
5080 one of these commands fails, then the remaining commands will be
5083 (2) If you execute several variables with one call to run (i. e.
5084 calling run with a list of variables as arguments), any failing
5085 command will cause "run" to terminate, i. e. the remaining
5086 variables are not executed.
5088 Note for Redundant Ethernet Interfaces:
5089 =======================================
5091 Some boards come with redundant Ethernet interfaces; U-Boot supports
5092 such configurations and is capable of automatic selection of a
5093 "working" interface when needed. MAC assignment works as follows:
5095 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5096 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5097 "eth1addr" (=>eth1), "eth2addr", ...
5099 If the network interface stores some valid MAC address (for instance
5100 in SROM), this is used as default address if there is NO correspon-
5101 ding setting in the environment; if the corresponding environment
5102 variable is set, this overrides the settings in the card; that means:
5104 o If the SROM has a valid MAC address, and there is no address in the
5105 environment, the SROM's address is used.
5107 o If there is no valid address in the SROM, and a definition in the
5108 environment exists, then the value from the environment variable is
5111 o If both the SROM and the environment contain a MAC address, and
5112 both addresses are the same, this MAC address is used.
5114 o If both the SROM and the environment contain a MAC address, and the
5115 addresses differ, the value from the environment is used and a
5118 o If neither SROM nor the environment contain a MAC address, an error
5119 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5120 a random, locally-assigned MAC is used.
5122 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5123 will be programmed into hardware as part of the initialization process. This
5124 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5125 The naming convention is as follows:
5126 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5131 U-Boot is capable of booting (and performing other auxiliary operations on)
5132 images in two formats:
5134 New uImage format (FIT)
5135 -----------------------
5137 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5138 to Flattened Device Tree). It allows the use of images with multiple
5139 components (several kernels, ramdisks, etc.), with contents protected by
5140 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5146 Old image format is based on binary files which can be basically anything,
5147 preceded by a special header; see the definitions in include/image.h for
5148 details; basically, the header defines the following image properties:
5150 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5151 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5152 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5153 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5155 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5156 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5157 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5158 * Compression Type (uncompressed, gzip, bzip2)
5164 The header is marked by a special Magic Number, and both the header
5165 and the data portions of the image are secured against corruption by
5172 Although U-Boot should support any OS or standalone application
5173 easily, the main focus has always been on Linux during the design of
5176 U-Boot includes many features that so far have been part of some
5177 special "boot loader" code within the Linux kernel. Also, any
5178 "initrd" images to be used are no longer part of one big Linux image;
5179 instead, kernel and "initrd" are separate images. This implementation
5180 serves several purposes:
5182 - the same features can be used for other OS or standalone
5183 applications (for instance: using compressed images to reduce the
5184 Flash memory footprint)
5186 - it becomes much easier to port new Linux kernel versions because
5187 lots of low-level, hardware dependent stuff are done by U-Boot
5189 - the same Linux kernel image can now be used with different "initrd"
5190 images; of course this also means that different kernel images can
5191 be run with the same "initrd". This makes testing easier (you don't
5192 have to build a new "zImage.initrd" Linux image when you just
5193 change a file in your "initrd"). Also, a field-upgrade of the
5194 software is easier now.
5200 Porting Linux to U-Boot based systems:
5201 ---------------------------------------
5203 U-Boot cannot save you from doing all the necessary modifications to
5204 configure the Linux device drivers for use with your target hardware
5205 (no, we don't intend to provide a full virtual machine interface to
5208 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5210 Just make sure your machine specific header file (for instance
5211 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5212 Information structure as we define in include/asm-<arch>/u-boot.h,
5213 and make sure that your definition of IMAP_ADDR uses the same value
5214 as your U-Boot configuration in CONFIG_SYS_IMMR.
5216 Note that U-Boot now has a driver model, a unified model for drivers.
5217 If you are adding a new driver, plumb it into driver model. If there
5218 is no uclass available, you are encouraged to create one. See
5222 Configuring the Linux kernel:
5223 -----------------------------
5225 No specific requirements for U-Boot. Make sure you have some root
5226 device (initial ramdisk, NFS) for your target system.
5229 Building a Linux Image:
5230 -----------------------
5232 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5233 not used. If you use recent kernel source, a new build target
5234 "uImage" will exist which automatically builds an image usable by
5235 U-Boot. Most older kernels also have support for a "pImage" target,
5236 which was introduced for our predecessor project PPCBoot and uses a
5237 100% compatible format.
5241 make TQM850L_defconfig
5246 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5247 encapsulate a compressed Linux kernel image with header information,
5248 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5250 * build a standard "vmlinux" kernel image (in ELF binary format):
5252 * convert the kernel into a raw binary image:
5254 ${CROSS_COMPILE}-objcopy -O binary \
5255 -R .note -R .comment \
5256 -S vmlinux linux.bin
5258 * compress the binary image:
5262 * package compressed binary image for U-Boot:
5264 mkimage -A ppc -O linux -T kernel -C gzip \
5265 -a 0 -e 0 -n "Linux Kernel Image" \
5266 -d linux.bin.gz uImage
5269 The "mkimage" tool can also be used to create ramdisk images for use
5270 with U-Boot, either separated from the Linux kernel image, or
5271 combined into one file. "mkimage" encapsulates the images with a 64
5272 byte header containing information about target architecture,
5273 operating system, image type, compression method, entry points, time
5274 stamp, CRC32 checksums, etc.
5276 "mkimage" can be called in two ways: to verify existing images and
5277 print the header information, or to build new images.
5279 In the first form (with "-l" option) mkimage lists the information
5280 contained in the header of an existing U-Boot image; this includes
5281 checksum verification:
5283 tools/mkimage -l image
5284 -l ==> list image header information
5286 The second form (with "-d" option) is used to build a U-Boot image
5287 from a "data file" which is used as image payload:
5289 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5290 -n name -d data_file image
5291 -A ==> set architecture to 'arch'
5292 -O ==> set operating system to 'os'
5293 -T ==> set image type to 'type'
5294 -C ==> set compression type 'comp'
5295 -a ==> set load address to 'addr' (hex)
5296 -e ==> set entry point to 'ep' (hex)
5297 -n ==> set image name to 'name'
5298 -d ==> use image data from 'datafile'
5300 Right now, all Linux kernels for PowerPC systems use the same load
5301 address (0x00000000), but the entry point address depends on the
5304 - 2.2.x kernels have the entry point at 0x0000000C,
5305 - 2.3.x and later kernels have the entry point at 0x00000000.
5307 So a typical call to build a U-Boot image would read:
5309 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5310 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5311 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5312 > examples/uImage.TQM850L
5313 Image Name: 2.4.4 kernel for TQM850L
5314 Created: Wed Jul 19 02:34:59 2000
5315 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5316 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5317 Load Address: 0x00000000
5318 Entry Point: 0x00000000
5320 To verify the contents of the image (or check for corruption):
5322 -> tools/mkimage -l examples/uImage.TQM850L
5323 Image Name: 2.4.4 kernel for TQM850L
5324 Created: Wed Jul 19 02:34:59 2000
5325 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5326 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5327 Load Address: 0x00000000
5328 Entry Point: 0x00000000
5330 NOTE: for embedded systems where boot time is critical you can trade
5331 speed for memory and install an UNCOMPRESSED image instead: this
5332 needs more space in Flash, but boots much faster since it does not
5333 need to be uncompressed:
5335 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5336 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5337 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5338 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5339 > examples/uImage.TQM850L-uncompressed
5340 Image Name: 2.4.4 kernel for TQM850L
5341 Created: Wed Jul 19 02:34:59 2000
5342 Image Type: PowerPC Linux Kernel Image (uncompressed)
5343 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5344 Load Address: 0x00000000
5345 Entry Point: 0x00000000
5348 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5349 when your kernel is intended to use an initial ramdisk:
5351 -> tools/mkimage -n 'Simple Ramdisk Image' \
5352 > -A ppc -O linux -T ramdisk -C gzip \
5353 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5354 Image Name: Simple Ramdisk Image
5355 Created: Wed Jan 12 14:01:50 2000
5356 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5357 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5358 Load Address: 0x00000000
5359 Entry Point: 0x00000000
5361 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5362 option performs the converse operation of the mkimage's second form (the "-d"
5363 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5366 tools/dumpimage -i image -T type -p position data_file
5367 -i ==> extract from the 'image' a specific 'data_file'
5368 -T ==> set image type to 'type'
5369 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5372 Installing a Linux Image:
5373 -------------------------
5375 To downloading a U-Boot image over the serial (console) interface,
5376 you must convert the image to S-Record format:
5378 objcopy -I binary -O srec examples/image examples/image.srec
5380 The 'objcopy' does not understand the information in the U-Boot
5381 image header, so the resulting S-Record file will be relative to
5382 address 0x00000000. To load it to a given address, you need to
5383 specify the target address as 'offset' parameter with the 'loads'
5386 Example: install the image to address 0x40100000 (which on the
5387 TQM8xxL is in the first Flash bank):
5389 => erase 40100000 401FFFFF
5395 ## Ready for S-Record download ...
5396 ~>examples/image.srec
5397 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5399 15989 15990 15991 15992
5400 [file transfer complete]
5402 ## Start Addr = 0x00000000
5405 You can check the success of the download using the 'iminfo' command;
5406 this includes a checksum verification so you can be sure no data
5407 corruption happened:
5411 ## Checking Image at 40100000 ...
5412 Image Name: 2.2.13 for initrd on TQM850L
5413 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5414 Data Size: 335725 Bytes = 327 kB = 0 MB
5415 Load Address: 00000000
5416 Entry Point: 0000000c
5417 Verifying Checksum ... OK
5423 The "bootm" command is used to boot an application that is stored in
5424 memory (RAM or Flash). In case of a Linux kernel image, the contents
5425 of the "bootargs" environment variable is passed to the kernel as
5426 parameters. You can check and modify this variable using the
5427 "printenv" and "setenv" commands:
5430 => printenv bootargs
5431 bootargs=root=/dev/ram
5433 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5435 => printenv bootargs
5436 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5439 ## Booting Linux kernel at 40020000 ...
5440 Image Name: 2.2.13 for NFS on TQM850L
5441 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5442 Data Size: 381681 Bytes = 372 kB = 0 MB
5443 Load Address: 00000000
5444 Entry Point: 0000000c
5445 Verifying Checksum ... OK
5446 Uncompressing Kernel Image ... OK
5447 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
5448 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5449 time_init: decrementer frequency = 187500000/60
5450 Calibrating delay loop... 49.77 BogoMIPS
5451 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5454 If you want to boot a Linux kernel with initial RAM disk, you pass
5455 the memory addresses of both the kernel and the initrd image (PPBCOOT
5456 format!) to the "bootm" command:
5458 => imi 40100000 40200000
5460 ## Checking Image at 40100000 ...
5461 Image Name: 2.2.13 for initrd on TQM850L
5462 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5463 Data Size: 335725 Bytes = 327 kB = 0 MB
5464 Load Address: 00000000
5465 Entry Point: 0000000c
5466 Verifying Checksum ... OK
5468 ## Checking Image at 40200000 ...
5469 Image Name: Simple Ramdisk Image
5470 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5471 Data Size: 566530 Bytes = 553 kB = 0 MB
5472 Load Address: 00000000
5473 Entry Point: 00000000
5474 Verifying Checksum ... OK
5476 => bootm 40100000 40200000
5477 ## Booting Linux kernel at 40100000 ...
5478 Image Name: 2.2.13 for initrd on TQM850L
5479 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5480 Data Size: 335725 Bytes = 327 kB = 0 MB
5481 Load Address: 00000000
5482 Entry Point: 0000000c
5483 Verifying Checksum ... OK
5484 Uncompressing Kernel Image ... OK
5485 ## Loading RAMDisk Image at 40200000 ...
5486 Image Name: Simple Ramdisk Image
5487 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5488 Data Size: 566530 Bytes = 553 kB = 0 MB
5489 Load Address: 00000000
5490 Entry Point: 00000000
5491 Verifying Checksum ... OK
5492 Loading Ramdisk ... OK
5493 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
5494 Boot arguments: root=/dev/ram
5495 time_init: decrementer frequency = 187500000/60
5496 Calibrating delay loop... 49.77 BogoMIPS
5498 RAMDISK: Compressed image found at block 0
5499 VFS: Mounted root (ext2 filesystem).
5503 Boot Linux and pass a flat device tree:
5506 First, U-Boot must be compiled with the appropriate defines. See the section
5507 titled "Linux Kernel Interface" above for a more in depth explanation. The
5508 following is an example of how to start a kernel and pass an updated
5514 oft=oftrees/mpc8540ads.dtb
5515 => tftp $oftaddr $oft
5516 Speed: 1000, full duplex
5518 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5519 Filename 'oftrees/mpc8540ads.dtb'.
5520 Load address: 0x300000
5523 Bytes transferred = 4106 (100a hex)
5524 => tftp $loadaddr $bootfile
5525 Speed: 1000, full duplex
5527 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5529 Load address: 0x200000
5530 Loading:############
5532 Bytes transferred = 1029407 (fb51f hex)
5537 => bootm $loadaddr - $oftaddr
5538 ## Booting image at 00200000 ...
5539 Image Name: Linux-2.6.17-dirty
5540 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5541 Data Size: 1029343 Bytes = 1005.2 kB
5542 Load Address: 00000000
5543 Entry Point: 00000000
5544 Verifying Checksum ... OK
5545 Uncompressing Kernel Image ... OK
5546 Booting using flat device tree at 0x300000
5547 Using MPC85xx ADS machine description
5548 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5552 More About U-Boot Image Types:
5553 ------------------------------
5555 U-Boot supports the following image types:
5557 "Standalone Programs" are directly runnable in the environment
5558 provided by U-Boot; it is expected that (if they behave
5559 well) you can continue to work in U-Boot after return from
5560 the Standalone Program.
5561 "OS Kernel Images" are usually images of some Embedded OS which
5562 will take over control completely. Usually these programs
5563 will install their own set of exception handlers, device
5564 drivers, set up the MMU, etc. - this means, that you cannot
5565 expect to re-enter U-Boot except by resetting the CPU.
5566 "RAMDisk Images" are more or less just data blocks, and their
5567 parameters (address, size) are passed to an OS kernel that is
5569 "Multi-File Images" contain several images, typically an OS
5570 (Linux) kernel image and one or more data images like
5571 RAMDisks. This construct is useful for instance when you want
5572 to boot over the network using BOOTP etc., where the boot
5573 server provides just a single image file, but you want to get
5574 for instance an OS kernel and a RAMDisk image.
5576 "Multi-File Images" start with a list of image sizes, each
5577 image size (in bytes) specified by an "uint32_t" in network
5578 byte order. This list is terminated by an "(uint32_t)0".
5579 Immediately after the terminating 0 follow the images, one by
5580 one, all aligned on "uint32_t" boundaries (size rounded up to
5581 a multiple of 4 bytes).
5583 "Firmware Images" are binary images containing firmware (like
5584 U-Boot or FPGA images) which usually will be programmed to
5587 "Script files" are command sequences that will be executed by
5588 U-Boot's command interpreter; this feature is especially
5589 useful when you configure U-Boot to use a real shell (hush)
5590 as command interpreter.
5592 Booting the Linux zImage:
5593 -------------------------
5595 On some platforms, it's possible to boot Linux zImage. This is done
5596 using the "bootz" command. The syntax of "bootz" command is the same
5597 as the syntax of "bootm" command.
5599 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5600 kernel with raw initrd images. The syntax is slightly different, the
5601 address of the initrd must be augmented by it's size, in the following
5602 format: "<initrd addres>:<initrd size>".
5608 One of the features of U-Boot is that you can dynamically load and
5609 run "standalone" applications, which can use some resources of
5610 U-Boot like console I/O functions or interrupt services.
5612 Two simple examples are included with the sources:
5617 'examples/hello_world.c' contains a small "Hello World" Demo
5618 application; it is automatically compiled when you build U-Boot.
5619 It's configured to run at address 0x00040004, so you can play with it
5623 ## Ready for S-Record download ...
5624 ~>examples/hello_world.srec
5625 1 2 3 4 5 6 7 8 9 10 11 ...
5626 [file transfer complete]
5628 ## Start Addr = 0x00040004
5630 => go 40004 Hello World! This is a test.
5631 ## Starting application at 0x00040004 ...
5642 Hit any key to exit ...
5644 ## Application terminated, rc = 0x0
5646 Another example, which demonstrates how to register a CPM interrupt
5647 handler with the U-Boot code, can be found in 'examples/timer.c'.
5648 Here, a CPM timer is set up to generate an interrupt every second.
5649 The interrupt service routine is trivial, just printing a '.'
5650 character, but this is just a demo program. The application can be
5651 controlled by the following keys:
5653 ? - print current values og the CPM Timer registers
5654 b - enable interrupts and start timer
5655 e - stop timer and disable interrupts
5656 q - quit application
5659 ## Ready for S-Record download ...
5660 ~>examples/timer.srec
5661 1 2 3 4 5 6 7 8 9 10 11 ...
5662 [file transfer complete]
5664 ## Start Addr = 0x00040004
5667 ## Starting application at 0x00040004 ...
5670 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5673 [q, b, e, ?] Set interval 1000000 us
5676 [q, b, e, ?] ........
5677 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5680 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5683 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5686 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5688 [q, b, e, ?] ...Stopping timer
5690 [q, b, e, ?] ## Application terminated, rc = 0x0
5696 Over time, many people have reported problems when trying to use the
5697 "minicom" terminal emulation program for serial download. I (wd)
5698 consider minicom to be broken, and recommend not to use it. Under
5699 Unix, I recommend to use C-Kermit for general purpose use (and
5700 especially for kermit binary protocol download ("loadb" command), and
5701 use "cu" for S-Record download ("loads" command). See
5702 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5703 for help with kermit.
5706 Nevertheless, if you absolutely want to use it try adding this
5707 configuration to your "File transfer protocols" section:
5709 Name Program Name U/D FullScr IO-Red. Multi
5710 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5711 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5717 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5718 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5720 Building requires a cross environment; it is known to work on
5721 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5722 need gmake since the Makefiles are not compatible with BSD make).
5723 Note that the cross-powerpc package does not install include files;
5724 attempting to build U-Boot will fail because <machine/ansi.h> is
5725 missing. This file has to be installed and patched manually:
5727 # cd /usr/pkg/cross/powerpc-netbsd/include
5729 # ln -s powerpc machine
5730 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5731 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5733 Native builds *don't* work due to incompatibilities between native
5734 and U-Boot include files.
5736 Booting assumes that (the first part of) the image booted is a
5737 stage-2 loader which in turn loads and then invokes the kernel
5738 proper. Loader sources will eventually appear in the NetBSD source
5739 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5740 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5743 Implementation Internals:
5744 =========================
5746 The following is not intended to be a complete description of every
5747 implementation detail. However, it should help to understand the
5748 inner workings of U-Boot and make it easier to port it to custom
5752 Initial Stack, Global Data:
5753 ---------------------------
5755 The implementation of U-Boot is complicated by the fact that U-Boot
5756 starts running out of ROM (flash memory), usually without access to
5757 system RAM (because the memory controller is not initialized yet).
5758 This means that we don't have writable Data or BSS segments, and BSS
5759 is not initialized as zero. To be able to get a C environment working
5760 at all, we have to allocate at least a minimal stack. Implementation
5761 options for this are defined and restricted by the CPU used: Some CPU
5762 models provide on-chip memory (like the IMMR area on MPC8xx and
5763 MPC826x processors), on others (parts of) the data cache can be
5764 locked as (mis-) used as memory, etc.
5766 Chris Hallinan posted a good summary of these issues to the
5767 U-Boot mailing list:
5769 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5770 From: "Chris Hallinan" <clh@net1plus.com>
5771 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5774 Correct me if I'm wrong, folks, but the way I understand it
5775 is this: Using DCACHE as initial RAM for Stack, etc, does not
5776 require any physical RAM backing up the cache. The cleverness
5777 is that the cache is being used as a temporary supply of
5778 necessary storage before the SDRAM controller is setup. It's
5779 beyond the scope of this list to explain the details, but you
5780 can see how this works by studying the cache architecture and
5781 operation in the architecture and processor-specific manuals.
5783 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5784 is another option for the system designer to use as an
5785 initial stack/RAM area prior to SDRAM being available. Either
5786 option should work for you. Using CS 4 should be fine if your
5787 board designers haven't used it for something that would
5788 cause you grief during the initial boot! It is frequently not
5791 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5792 with your processor/board/system design. The default value
5793 you will find in any recent u-boot distribution in
5794 walnut.h should work for you. I'd set it to a value larger
5795 than your SDRAM module. If you have a 64MB SDRAM module, set
5796 it above 400_0000. Just make sure your board has no resources
5797 that are supposed to respond to that address! That code in
5798 start.S has been around a while and should work as is when
5799 you get the config right.
5804 It is essential to remember this, since it has some impact on the C
5805 code for the initialization procedures:
5807 * Initialized global data (data segment) is read-only. Do not attempt
5810 * Do not use any uninitialized global data (or implicitly initialized
5811 as zero data - BSS segment) at all - this is undefined, initiali-
5812 zation is performed later (when relocating to RAM).
5814 * Stack space is very limited. Avoid big data buffers or things like
5817 Having only the stack as writable memory limits means we cannot use
5818 normal global data to share information between the code. But it
5819 turned out that the implementation of U-Boot can be greatly
5820 simplified by making a global data structure (gd_t) available to all
5821 functions. We could pass a pointer to this data as argument to _all_
5822 functions, but this would bloat the code. Instead we use a feature of
5823 the GCC compiler (Global Register Variables) to share the data: we
5824 place a pointer (gd) to the global data into a register which we
5825 reserve for this purpose.
5827 When choosing a register for such a purpose we are restricted by the
5828 relevant (E)ABI specifications for the current architecture, and by
5829 GCC's implementation.
5831 For PowerPC, the following registers have specific use:
5833 R2: reserved for system use
5834 R3-R4: parameter passing and return values
5835 R5-R10: parameter passing
5836 R13: small data area pointer
5840 (U-Boot also uses R12 as internal GOT pointer. r12
5841 is a volatile register so r12 needs to be reset when
5842 going back and forth between asm and C)
5844 ==> U-Boot will use R2 to hold a pointer to the global data
5846 Note: on PPC, we could use a static initializer (since the
5847 address of the global data structure is known at compile time),
5848 but it turned out that reserving a register results in somewhat
5849 smaller code - although the code savings are not that big (on
5850 average for all boards 752 bytes for the whole U-Boot image,
5851 624 text + 127 data).
5853 On ARM, the following registers are used:
5855 R0: function argument word/integer result
5856 R1-R3: function argument word
5857 R9: platform specific
5858 R10: stack limit (used only if stack checking is enabled)
5859 R11: argument (frame) pointer
5860 R12: temporary workspace
5863 R15: program counter
5865 ==> U-Boot will use R9 to hold a pointer to the global data
5867 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5869 On Nios II, the ABI is documented here:
5870 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5872 ==> U-Boot will use gp to hold a pointer to the global data
5874 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5875 to access small data sections, so gp is free.
5877 On NDS32, the following registers are used:
5879 R0-R1: argument/return
5881 R15: temporary register for assembler
5882 R16: trampoline register
5883 R28: frame pointer (FP)
5884 R29: global pointer (GP)
5885 R30: link register (LP)
5886 R31: stack pointer (SP)
5887 PC: program counter (PC)
5889 ==> U-Boot will use R10 to hold a pointer to the global data
5891 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5892 or current versions of GCC may "optimize" the code too much.
5897 U-Boot runs in system state and uses physical addresses, i.e. the
5898 MMU is not used either for address mapping nor for memory protection.
5900 The available memory is mapped to fixed addresses using the memory
5901 controller. In this process, a contiguous block is formed for each
5902 memory type (Flash, SDRAM, SRAM), even when it consists of several
5903 physical memory banks.
5905 U-Boot is installed in the first 128 kB of the first Flash bank (on
5906 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5907 booting and sizing and initializing DRAM, the code relocates itself
5908 to the upper end of DRAM. Immediately below the U-Boot code some
5909 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5910 configuration setting]. Below that, a structure with global Board
5911 Info data is placed, followed by the stack (growing downward).
5913 Additionally, some exception handler code is copied to the low 8 kB
5914 of DRAM (0x00000000 ... 0x00001FFF).
5916 So a typical memory configuration with 16 MB of DRAM could look like
5919 0x0000 0000 Exception Vector code
5922 0x0000 2000 Free for Application Use
5928 0x00FB FF20 Monitor Stack (Growing downward)
5929 0x00FB FFAC Board Info Data and permanent copy of global data
5930 0x00FC 0000 Malloc Arena
5933 0x00FE 0000 RAM Copy of Monitor Code
5934 ... eventually: LCD or video framebuffer
5935 ... eventually: pRAM (Protected RAM - unchanged by reset)
5936 0x00FF FFFF [End of RAM]
5939 System Initialization:
5940 ----------------------
5942 In the reset configuration, U-Boot starts at the reset entry point
5943 (on most PowerPC systems at address 0x00000100). Because of the reset
5944 configuration for CS0# this is a mirror of the on board Flash memory.
5945 To be able to re-map memory U-Boot then jumps to its link address.
5946 To be able to implement the initialization code in C, a (small!)
5947 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5948 which provide such a feature like MPC8xx or MPC8260), or in a locked
5949 part of the data cache. After that, U-Boot initializes the CPU core,
5950 the caches and the SIU.
5952 Next, all (potentially) available memory banks are mapped using a
5953 preliminary mapping. For example, we put them on 512 MB boundaries
5954 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5955 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5956 programmed for SDRAM access. Using the temporary configuration, a
5957 simple memory test is run that determines the size of the SDRAM
5960 When there is more than one SDRAM bank, and the banks are of
5961 different size, the largest is mapped first. For equal size, the first
5962 bank (CS2#) is mapped first. The first mapping is always for address
5963 0x00000000, with any additional banks following immediately to create
5964 contiguous memory starting from 0.
5966 Then, the monitor installs itself at the upper end of the SDRAM area
5967 and allocates memory for use by malloc() and for the global Board
5968 Info data; also, the exception vector code is copied to the low RAM
5969 pages, and the final stack is set up.
5971 Only after this relocation will you have a "normal" C environment;
5972 until that you are restricted in several ways, mostly because you are
5973 running from ROM, and because the code will have to be relocated to a
5977 U-Boot Porting Guide:
5978 ----------------------
5980 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5984 int main(int argc, char *argv[])
5986 sighandler_t no_more_time;
5988 signal(SIGALRM, no_more_time);
5989 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5991 if (available_money > available_manpower) {
5992 Pay consultant to port U-Boot;
5996 Download latest U-Boot source;
5998 Subscribe to u-boot mailing list;
6001 email("Hi, I am new to U-Boot, how do I get started?");
6004 Read the README file in the top level directory;
6005 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6006 Read applicable doc/*.README;
6007 Read the source, Luke;
6008 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6011 if (available_money > toLocalCurrency ($2500))
6014 Add a lot of aggravation and time;
6016 if (a similar board exists) { /* hopefully... */
6017 cp -a board/<similar> board/<myboard>
6018 cp include/configs/<similar>.h include/configs/<myboard>.h
6020 Create your own board support subdirectory;
6021 Create your own board include/configs/<myboard>.h file;
6023 Edit new board/<myboard> files
6024 Edit new include/configs/<myboard>.h
6029 Add / modify source code;
6033 email("Hi, I am having problems...");
6035 Send patch file to the U-Boot email list;
6036 if (reasonable critiques)
6037 Incorporate improvements from email list code review;
6039 Defend code as written;
6045 void no_more_time (int sig)
6054 All contributions to U-Boot should conform to the Linux kernel
6055 coding style; see the file "Documentation/CodingStyle" and the script
6056 "scripts/Lindent" in your Linux kernel source directory.
6058 Source files originating from a different project (for example the
6059 MTD subsystem) are generally exempt from these guidelines and are not
6060 reformatted to ease subsequent migration to newer versions of those
6063 Please note that U-Boot is implemented in C (and to some small parts in
6064 Assembler); no C++ is used, so please do not use C++ style comments (//)
6067 Please also stick to the following formatting rules:
6068 - remove any trailing white space
6069 - use TAB characters for indentation and vertical alignment, not spaces
6070 - make sure NOT to use DOS '\r\n' line feeds
6071 - do not add more than 2 consecutive empty lines to source files
6072 - do not add trailing empty lines to source files
6074 Submissions which do not conform to the standards may be returned
6075 with a request to reformat the changes.
6081 Since the number of patches for U-Boot is growing, we need to
6082 establish some rules. Submissions which do not conform to these rules
6083 may be rejected, even when they contain important and valuable stuff.
6085 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6087 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6088 see http://lists.denx.de/mailman/listinfo/u-boot
6090 When you send a patch, please include the following information with
6093 * For bug fixes: a description of the bug and how your patch fixes
6094 this bug. Please try to include a way of demonstrating that the
6095 patch actually fixes something.
6097 * For new features: a description of the feature and your
6100 * A CHANGELOG entry as plaintext (separate from the patch)
6102 * For major contributions, add a MAINTAINERS file with your
6103 information and associated file and directory references.
6105 * When you add support for a new board, don't forget to add a
6106 maintainer e-mail address to the boards.cfg file, too.
6108 * If your patch adds new configuration options, don't forget to
6109 document these in the README file.
6111 * The patch itself. If you are using git (which is *strongly*
6112 recommended) you can easily generate the patch using the
6113 "git format-patch". If you then use "git send-email" to send it to
6114 the U-Boot mailing list, you will avoid most of the common problems
6115 with some other mail clients.
6117 If you cannot use git, use "diff -purN OLD NEW". If your version of
6118 diff does not support these options, then get the latest version of
6121 The current directory when running this command shall be the parent
6122 directory of the U-Boot source tree (i. e. please make sure that
6123 your patch includes sufficient directory information for the
6126 We prefer patches as plain text. MIME attachments are discouraged,
6127 and compressed attachments must not be used.
6129 * If one logical set of modifications affects or creates several
6130 files, all these changes shall be submitted in a SINGLE patch file.
6132 * Changesets that contain different, unrelated modifications shall be
6133 submitted as SEPARATE patches, one patch per changeset.
6138 * Before sending the patch, run the buildman script on your patched
6139 source tree and make sure that no errors or warnings are reported
6140 for any of the boards.
6142 * Keep your modifications to the necessary minimum: A patch
6143 containing several unrelated changes or arbitrary reformats will be
6144 returned with a request to re-formatting / split it.
6146 * If you modify existing code, make sure that your new code does not
6147 add to the memory footprint of the code ;-) Small is beautiful!
6148 When adding new features, these should compile conditionally only
6149 (using #ifdef), and the resulting code with the new feature
6150 disabled must not need more memory than the old code without your
6153 * Remember that there is a size limit of 100 kB per message on the
6154 u-boot mailing list. Bigger patches will be moderated. If they are
6155 reasonable and not too big, they will be acknowledged. But patches
6156 bigger than the size limit should be avoided.
projects / oweals / u-boot.git / blob