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_BMP * BMP support
827 CONFIG_CMD_BSP * Board specific commands
828 CONFIG_CMD_BOOTD bootd
829 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
830 CONFIG_CMD_CACHE * icache, dcache
831 CONFIG_CMD_CLK * clock command support
832 CONFIG_CMD_CONSOLE coninfo
833 CONFIG_CMD_CRC32 * crc32
834 CONFIG_CMD_DATE * support for RTC, date/time...
835 CONFIG_CMD_DHCP * DHCP support
836 CONFIG_CMD_DIAG * Diagnostics
837 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
838 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
839 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
840 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
841 CONFIG_CMD_DTT * Digital Therm and Thermostat
842 CONFIG_CMD_ECHO echo arguments
843 CONFIG_CMD_EDITENV edit env variable
844 CONFIG_CMD_EEPROM * EEPROM read/write support
845 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
846 CONFIG_CMD_ELF * bootelf, bootvx
847 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
848 CONFIG_CMD_ENV_FLAGS * display details about env flags
849 CONFIG_CMD_ENV_EXISTS * check existence of env variable
850 CONFIG_CMD_EXPORTENV * export the environment
851 CONFIG_CMD_EXT2 * ext2 command support
852 CONFIG_CMD_EXT4 * ext4 command support
853 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
854 that work for multiple fs types
855 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
856 CONFIG_CMD_SAVEENV saveenv
857 CONFIG_CMD_FDC * Floppy Disk Support
858 CONFIG_CMD_FAT * FAT command support
859 CONFIG_CMD_FLASH flinfo, erase, protect
860 CONFIG_CMD_FPGA FPGA device initialization support
861 CONFIG_CMD_FUSE * Device fuse support
862 CONFIG_CMD_GETTIME * Get time since boot
863 CONFIG_CMD_GO * the 'go' command (exec code)
864 CONFIG_CMD_GREPENV * search environment
865 CONFIG_CMD_HASH * calculate hash / digest
866 CONFIG_CMD_I2C * I2C serial bus support
867 CONFIG_CMD_IDE * IDE harddisk support
868 CONFIG_CMD_IMI iminfo
869 CONFIG_CMD_IMLS List all images found in NOR flash
870 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
871 CONFIG_CMD_IMMAP * IMMR dump support
872 CONFIG_CMD_IOTRACE * I/O tracing for debugging
873 CONFIG_CMD_IMPORTENV * import an environment
874 CONFIG_CMD_INI * import data from an ini file into the env
875 CONFIG_CMD_IRQ * irqinfo
876 CONFIG_CMD_ITEST Integer/string test of 2 values
877 CONFIG_CMD_JFFS2 * JFFS2 Support
878 CONFIG_CMD_KGDB * kgdb
879 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
880 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
882 CONFIG_CMD_LOADB loadb
883 CONFIG_CMD_LOADS loads
884 CONFIG_CMD_MD5SUM * print md5 message digest
885 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
886 CONFIG_CMD_MEMINFO * Display detailed memory information
887 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
889 CONFIG_CMD_MEMTEST * mtest
890 CONFIG_CMD_MISC Misc functions like sleep etc
891 CONFIG_CMD_MMC * MMC memory mapped support
892 CONFIG_CMD_MII * MII utility commands
893 CONFIG_CMD_MTDPARTS * MTD partition support
894 CONFIG_CMD_NAND * NAND support
895 CONFIG_CMD_NET bootp, tftpboot, rarpboot
896 CONFIG_CMD_NFS NFS support
897 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
898 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
899 CONFIG_CMD_PCI * pciinfo
900 CONFIG_CMD_PCMCIA * PCMCIA support
901 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
903 CONFIG_CMD_PORTIO * Port I/O
904 CONFIG_CMD_READ * Read raw data from partition
905 CONFIG_CMD_REGINFO * Register dump
906 CONFIG_CMD_RUN run command in env variable
907 CONFIG_CMD_SANDBOX * sb command to access sandbox features
908 CONFIG_CMD_SAVES * save S record dump
909 CONFIG_SCSI * SCSI Support
910 CONFIG_CMD_SDRAM * print SDRAM configuration information
911 (requires CONFIG_CMD_I2C)
912 CONFIG_CMD_SETGETDCR Support for DCR Register access
914 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
915 CONFIG_CMD_SHA1SUM * print sha1 memory digest
916 (requires CONFIG_CMD_MEMORY)
917 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
918 CONFIG_CMD_SOURCE "source" command Support
919 CONFIG_CMD_SPI * SPI serial bus support
920 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
921 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
922 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
923 CONFIG_CMD_TIMER * access to the system tick timer
924 CONFIG_CMD_USB * USB support
925 CONFIG_CMD_CDP * Cisco Discover Protocol support
926 CONFIG_CMD_MFSL * Microblaze FSL support
927 CONFIG_CMD_XIMG Load part of Multi Image
928 CONFIG_CMD_UUID * Generate random UUID or GUID string
930 EXAMPLE: If you want all functions except of network
931 support you can write:
933 #include "config_cmd_all.h"
934 #undef CONFIG_CMD_NET
937 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
939 Note: Don't enable the "icache" and "dcache" commands
940 (configuration option CONFIG_CMD_CACHE) unless you know
941 what you (and your U-Boot users) are doing. Data
942 cache cannot be enabled on systems like the 8xx or
943 8260 (where accesses to the IMMR region must be
944 uncached), and it cannot be disabled on all other
945 systems where we (mis-) use the data cache to hold an
946 initial stack and some data.
949 XXX - this list needs to get updated!
951 - Removal of commands
952 If no commands are needed to boot, you can disable
953 CONFIG_CMDLINE to remove them. In this case, the command line
954 will not be available, and when U-Boot wants to execute the
955 boot command (on start-up) it will call board_run_command()
956 instead. This can reduce image size significantly for very
957 simple boot procedures.
959 - Regular expression support:
961 If this variable is defined, U-Boot is linked against
962 the SLRE (Super Light Regular Expression) library,
963 which adds regex support to some commands, as for
964 example "env grep" and "setexpr".
968 If this variable is defined, U-Boot will use a device tree
969 to configure its devices, instead of relying on statically
970 compiled #defines in the board file. This option is
971 experimental and only available on a few boards. The device
972 tree is available in the global data as gd->fdt_blob.
974 U-Boot needs to get its device tree from somewhere. This can
975 be done using one of the two options below:
978 If this variable is defined, U-Boot will embed a device tree
979 binary in its image. This device tree file should be in the
980 board directory and called <soc>-<board>.dts. The binary file
981 is then picked up in board_init_f() and made available through
982 the global data structure as gd->blob.
985 If this variable is defined, U-Boot will build a device tree
986 binary. It will be called u-boot.dtb. Architecture-specific
987 code will locate it at run-time. Generally this works by:
989 cat u-boot.bin u-boot.dtb >image.bin
991 and in fact, U-Boot does this for you, creating a file called
992 u-boot-dtb.bin which is useful in the common case. You can
993 still use the individual files if you need something more
998 If this variable is defined, it enables watchdog
999 support for the SoC. There must be support in the SoC
1000 specific code for a watchdog. For the 8xx and 8260
1001 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1002 register. When supported for a specific SoC is
1003 available, then no further board specific code should
1004 be needed to use it.
1007 When using a watchdog circuitry external to the used
1008 SoC, then define this variable and provide board
1009 specific code for the "hw_watchdog_reset" function.
1011 CONFIG_AT91_HW_WDT_TIMEOUT
1012 specify the timeout in seconds. default 2 seconds.
1015 CONFIG_VERSION_VARIABLE
1016 If this variable is defined, an environment variable
1017 named "ver" is created by U-Boot showing the U-Boot
1018 version as printed by the "version" command.
1019 Any change to this variable will be reverted at the
1024 When CONFIG_CMD_DATE is selected, the type of the RTC
1025 has to be selected, too. Define exactly one of the
1028 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1029 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1030 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1031 CONFIG_RTC_MC146818 - use MC146818 RTC
1032 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1033 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1034 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1035 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1036 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1037 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1038 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1039 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1040 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1043 Note that if the RTC uses I2C, then the I2C interface
1044 must also be configured. See I2C Support, below.
1047 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1049 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1050 chip-ngpio pairs that tell the PCA953X driver the number of
1051 pins supported by a particular chip.
1053 Note that if the GPIO device uses I2C, then the I2C interface
1054 must also be configured. See I2C Support, below.
1057 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1058 accesses and can checksum them or write a list of them out
1059 to memory. See the 'iotrace' command for details. This is
1060 useful for testing device drivers since it can confirm that
1061 the driver behaves the same way before and after a code
1062 change. Currently this is supported on sandbox and arm. To
1063 add support for your architecture, add '#include <iotrace.h>'
1064 to the bottom of arch/<arch>/include/asm/io.h and test.
1066 Example output from the 'iotrace stats' command is below.
1067 Note that if the trace buffer is exhausted, the checksum will
1068 still continue to operate.
1071 Start: 10000000 (buffer start address)
1072 Size: 00010000 (buffer size)
1073 Offset: 00000120 (current buffer offset)
1074 Output: 10000120 (start + offset)
1075 Count: 00000018 (number of trace records)
1076 CRC32: 9526fb66 (CRC32 of all trace records)
1078 - Timestamp Support:
1080 When CONFIG_TIMESTAMP is selected, the timestamp
1081 (date and time) of an image is printed by image
1082 commands like bootm or iminfo. This option is
1083 automatically enabled when you select CONFIG_CMD_DATE .
1085 - Partition Labels (disklabels) Supported:
1086 Zero or more of the following:
1087 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1088 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1089 Intel architecture, USB sticks, etc.
1090 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1091 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1092 bootloader. Note 2TB partition limit; see
1094 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1096 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1097 CONFIG_SCSI) you must configure support for at
1098 least one non-MTD partition type as well.
1101 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1102 board configurations files but used nowhere!
1104 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1105 be performed by calling the function
1106 ide_set_reset(int reset)
1107 which has to be defined in a board specific file
1112 Set this to enable ATAPI support.
1117 Set this to enable support for disks larger than 137GB
1118 Also look at CONFIG_SYS_64BIT_LBA.
1119 Whithout these , LBA48 support uses 32bit variables and will 'only'
1120 support disks up to 2.1TB.
1122 CONFIG_SYS_64BIT_LBA:
1123 When enabled, makes the IDE subsystem use 64bit sector addresses.
1127 At the moment only there is only support for the
1128 SYM53C8XX SCSI controller; define
1129 CONFIG_SCSI_SYM53C8XX to enable it.
1131 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1132 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1133 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1134 maximum numbers of LUNs, SCSI ID's and target
1136 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1138 The environment variable 'scsidevs' is set to the number of
1139 SCSI devices found during the last scan.
1141 - NETWORK Support (PCI):
1143 Support for Intel 8254x/8257x gigabit chips.
1146 Utility code for direct access to the SPI bus on Intel 8257x.
1147 This does not do anything useful unless you set at least one
1148 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1150 CONFIG_E1000_SPI_GENERIC
1151 Allow generic access to the SPI bus on the Intel 8257x, for
1152 example with the "sspi" command.
1155 Management command for E1000 devices. When used on devices
1156 with SPI support you can reprogram the EEPROM from U-Boot.
1159 Support for Intel 82557/82559/82559ER chips.
1160 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1161 write routine for first time initialisation.
1164 Support for Digital 2114x chips.
1165 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1166 modem chip initialisation (KS8761/QS6611).
1169 Support for National dp83815 chips.
1172 Support for National dp8382[01] gigabit chips.
1174 - NETWORK Support (other):
1176 CONFIG_DRIVER_AT91EMAC
1177 Support for AT91RM9200 EMAC.
1180 Define this to use reduced MII inteface
1182 CONFIG_DRIVER_AT91EMAC_QUIET
1183 If this defined, the driver is quiet.
1184 The driver doen't show link status messages.
1186 CONFIG_CALXEDA_XGMAC
1187 Support for the Calxeda XGMAC device
1190 Support for SMSC's LAN91C96 chips.
1192 CONFIG_LAN91C96_USE_32_BIT
1193 Define this to enable 32 bit addressing
1196 Support for SMSC's LAN91C111 chip
1198 CONFIG_SMC91111_BASE
1199 Define this to hold the physical address
1200 of the device (I/O space)
1202 CONFIG_SMC_USE_32_BIT
1203 Define this if data bus is 32 bits
1205 CONFIG_SMC_USE_IOFUNCS
1206 Define this to use i/o functions instead of macros
1207 (some hardware wont work with macros)
1209 CONFIG_DRIVER_TI_EMAC
1210 Support for davinci emac
1212 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1213 Define this if you have more then 3 PHYs.
1216 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1218 CONFIG_FTGMAC100_EGIGA
1219 Define this to use GE link update with gigabit PHY.
1220 Define this if FTGMAC100 is connected to gigabit PHY.
1221 If your system has 10/100 PHY only, it might not occur
1222 wrong behavior. Because PHY usually return timeout or
1223 useless data when polling gigabit status and gigabit
1224 control registers. This behavior won't affect the
1225 correctnessof 10/100 link speed update.
1228 Support for SMSC's LAN911x and LAN921x chips
1231 Define this to hold the physical address
1232 of the device (I/O space)
1234 CONFIG_SMC911X_32_BIT
1235 Define this if data bus is 32 bits
1237 CONFIG_SMC911X_16_BIT
1238 Define this if data bus is 16 bits. If your processor
1239 automatically converts one 32 bit word to two 16 bit
1240 words you may also try CONFIG_SMC911X_32_BIT.
1243 Support for Renesas on-chip Ethernet controller
1245 CONFIG_SH_ETHER_USE_PORT
1246 Define the number of ports to be used
1248 CONFIG_SH_ETHER_PHY_ADDR
1249 Define the ETH PHY's address
1251 CONFIG_SH_ETHER_CACHE_WRITEBACK
1252 If this option is set, the driver enables cache flush.
1256 Support for PWM module on the imx6.
1260 Support TPM devices.
1262 CONFIG_TPM_TIS_INFINEON
1263 Support for Infineon i2c bus TPM devices. Only one device
1264 per system is supported at this time.
1266 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1267 Define the burst count bytes upper limit
1270 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1272 CONFIG_TPM_ST33ZP24_I2C
1273 Support for STMicroelectronics ST33ZP24 I2C devices.
1274 Requires TPM_ST33ZP24 and I2C.
1276 CONFIG_TPM_ST33ZP24_SPI
1277 Support for STMicroelectronics ST33ZP24 SPI devices.
1278 Requires TPM_ST33ZP24 and SPI.
1280 CONFIG_TPM_ATMEL_TWI
1281 Support for Atmel TWI TPM device. Requires I2C support.
1284 Support for generic parallel port TPM devices. Only one device
1285 per system is supported at this time.
1287 CONFIG_TPM_TIS_BASE_ADDRESS
1288 Base address where the generic TPM device is mapped
1289 to. Contemporary x86 systems usually map it at
1293 Add tpm monitor functions.
1294 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1295 provides monitor access to authorized functions.
1298 Define this to enable the TPM support library which provides
1299 functional interfaces to some TPM commands.
1300 Requires support for a TPM device.
1302 CONFIG_TPM_AUTH_SESSIONS
1303 Define this to enable authorized functions in the TPM library.
1304 Requires CONFIG_TPM and CONFIG_SHA1.
1307 At the moment only the UHCI host controller is
1308 supported (PIP405, MIP405, MPC5200); define
1309 CONFIG_USB_UHCI to enable it.
1310 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1311 and define CONFIG_USB_STORAGE to enable the USB
1314 Supported are USB Keyboards and USB Floppy drives
1316 MPC5200 USB requires additional defines:
1318 for 528 MHz Clock: 0x0001bbbb
1322 for differential drivers: 0x00001000
1323 for single ended drivers: 0x00005000
1324 for differential drivers on PSC3: 0x00000100
1325 for single ended drivers on PSC3: 0x00004100
1326 CONFIG_SYS_USB_EVENT_POLL
1327 May be defined to allow interrupt polling
1328 instead of using asynchronous interrupts
1330 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1331 txfilltuning field in the EHCI controller on reset.
1333 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1334 HW module registers.
1337 Define the below if you wish to use the USB console.
1338 Once firmware is rebuilt from a serial console issue the
1339 command "setenv stdin usbtty; setenv stdout usbtty" and
1340 attach your USB cable. The Unix command "dmesg" should print
1341 it has found a new device. The environment variable usbtty
1342 can be set to gserial or cdc_acm to enable your device to
1343 appear to a USB host as a Linux gserial device or a
1344 Common Device Class Abstract Control Model serial device.
1345 If you select usbtty = gserial you should be able to enumerate
1347 # modprobe usbserial vendor=0xVendorID product=0xProductID
1348 else if using cdc_acm, simply setting the environment
1349 variable usbtty to be cdc_acm should suffice. The following
1350 might be defined in YourBoardName.h
1353 Define this to build a UDC device
1356 Define this to have a tty type of device available to
1357 talk to the UDC device
1360 Define this to enable the high speed support for usb
1361 device and usbtty. If this feature is enabled, a routine
1362 int is_usbd_high_speed(void)
1363 also needs to be defined by the driver to dynamically poll
1364 whether the enumeration has succeded at high speed or full
1367 CONFIG_SYS_CONSOLE_IS_IN_ENV
1368 Define this if you want stdin, stdout &/or stderr to
1372 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1373 Derive USB clock from external clock "blah"
1374 - CONFIG_SYS_USB_EXTC_CLK 0x02
1376 If you have a USB-IF assigned VendorID then you may wish to
1377 define your own vendor specific values either in BoardName.h
1378 or directly in usbd_vendor_info.h. If you don't define
1379 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1380 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1381 should pretend to be a Linux device to it's target host.
1383 CONFIG_USBD_MANUFACTURER
1384 Define this string as the name of your company for
1385 - CONFIG_USBD_MANUFACTURER "my company"
1387 CONFIG_USBD_PRODUCT_NAME
1388 Define this string as the name of your product
1389 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1391 CONFIG_USBD_VENDORID
1392 Define this as your assigned Vendor ID from the USB
1393 Implementors Forum. This *must* be a genuine Vendor ID
1394 to avoid polluting the USB namespace.
1395 - CONFIG_USBD_VENDORID 0xFFFF
1397 CONFIG_USBD_PRODUCTID
1398 Define this as the unique Product ID
1400 - CONFIG_USBD_PRODUCTID 0xFFFF
1402 - ULPI Layer Support:
1403 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1404 the generic ULPI layer. The generic layer accesses the ULPI PHY
1405 via the platform viewport, so you need both the genric layer and
1406 the viewport enabled. Currently only Chipidea/ARC based
1407 viewport is supported.
1408 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1409 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1410 If your ULPI phy needs a different reference clock than the
1411 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1412 the appropriate value in Hz.
1415 The MMC controller on the Intel PXA is supported. To
1416 enable this define CONFIG_MMC. The MMC can be
1417 accessed from the boot prompt by mapping the device
1418 to physical memory similar to flash. Command line is
1419 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1420 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1423 Support for Renesas on-chip MMCIF controller
1425 CONFIG_SH_MMCIF_ADDR
1426 Define the base address of MMCIF registers
1429 Define the clock frequency for MMCIF
1431 CONFIG_SUPPORT_EMMC_BOOT
1432 Enable some additional features of the eMMC boot partitions.
1434 CONFIG_SUPPORT_EMMC_RPMB
1435 Enable the commands for reading, writing and programming the
1436 key for the Replay Protection Memory Block partition in eMMC.
1438 - USB Device Firmware Update (DFU) class support:
1439 CONFIG_USB_FUNCTION_DFU
1440 This enables the USB portion of the DFU USB class
1443 This enables the command "dfu" which is used to have
1444 U-Boot create a DFU class device via USB. This command
1445 requires that the "dfu_alt_info" environment variable be
1446 set and define the alt settings to expose to the host.
1449 This enables support for exposing (e)MMC devices via DFU.
1452 This enables support for exposing NAND devices via DFU.
1455 This enables support for exposing RAM via DFU.
1456 Note: DFU spec refer to non-volatile memory usage, but
1457 allow usages beyond the scope of spec - here RAM usage,
1458 one that would help mostly the developer.
1460 CONFIG_SYS_DFU_DATA_BUF_SIZE
1461 Dfu transfer uses a buffer before writing data to the
1462 raw storage device. Make the size (in bytes) of this buffer
1463 configurable. The size of this buffer is also configurable
1464 through the "dfu_bufsiz" environment variable.
1466 CONFIG_SYS_DFU_MAX_FILE_SIZE
1467 When updating files rather than the raw storage device,
1468 we use a static buffer to copy the file into and then write
1469 the buffer once we've been given the whole file. Define
1470 this to the maximum filesize (in bytes) for the buffer.
1471 Default is 4 MiB if undefined.
1473 DFU_DEFAULT_POLL_TIMEOUT
1474 Poll timeout [ms], is the timeout a device can send to the
1475 host. The host must wait for this timeout before sending
1476 a subsequent DFU_GET_STATUS request to the device.
1478 DFU_MANIFEST_POLL_TIMEOUT
1479 Poll timeout [ms], which the device sends to the host when
1480 entering dfuMANIFEST state. Host waits this timeout, before
1481 sending again an USB request to the device.
1483 - USB Device Android Fastboot support:
1484 CONFIG_USB_FUNCTION_FASTBOOT
1485 This enables the USB part of the fastboot gadget
1488 This enables the command "fastboot" which enables the Android
1489 fastboot mode for the platform's USB device. Fastboot is a USB
1490 protocol for downloading images, flashing and device control
1491 used on Android devices.
1492 See doc/README.android-fastboot for more information.
1494 CONFIG_ANDROID_BOOT_IMAGE
1495 This enables support for booting images which use the Android
1496 image format header.
1498 CONFIG_FASTBOOT_BUF_ADDR
1499 The fastboot protocol requires a large memory buffer for
1500 downloads. Define this to the starting RAM address to use for
1503 CONFIG_FASTBOOT_BUF_SIZE
1504 The fastboot protocol requires a large memory buffer for
1505 downloads. This buffer should be as large as possible for a
1506 platform. Define this to the size available RAM for fastboot.
1508 CONFIG_FASTBOOT_FLASH
1509 The fastboot protocol includes a "flash" command for writing
1510 the downloaded image to a non-volatile storage device. Define
1511 this to enable the "fastboot flash" command.
1513 CONFIG_FASTBOOT_FLASH_MMC_DEV
1514 The fastboot "flash" command requires additional information
1515 regarding the non-volatile storage device. Define this to
1516 the eMMC device that fastboot should use to store the image.
1518 CONFIG_FASTBOOT_GPT_NAME
1519 The fastboot "flash" command supports writing the downloaded
1520 image to the Protective MBR and the Primary GUID Partition
1521 Table. (Additionally, this downloaded image is post-processed
1522 to generate and write the Backup GUID Partition Table.)
1523 This occurs when the specified "partition name" on the
1524 "fastboot flash" command line matches this value.
1525 The default is "gpt" if undefined.
1527 CONFIG_FASTBOOT_MBR_NAME
1528 The fastboot "flash" command supports writing the downloaded
1530 This occurs when the "partition name" specified on the
1531 "fastboot flash" command line matches this value.
1532 If not defined the default value "mbr" is used.
1534 - Journaling Flash filesystem support:
1536 Define these for a default partition on a NAND device
1538 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1539 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1540 Define these for a default partition on a NOR device
1542 - FAT(File Allocation Table) filesystem write function support:
1545 Define this to enable support for saving memory data as a
1546 file in FAT formatted partition.
1548 This will also enable the command "fatwrite" enabling the
1549 user to write files to FAT.
1551 - CBFS (Coreboot Filesystem) support:
1554 Define this to enable support for reading from a Coreboot
1555 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1558 - FAT(File Allocation Table) filesystem cluster size:
1559 CONFIG_FS_FAT_MAX_CLUSTSIZE
1561 Define the max cluster size for fat operations else
1562 a default value of 65536 will be defined.
1565 See Kconfig help for available keyboard drivers.
1569 Define this to enable a custom keyboard support.
1570 This simply calls drv_keyboard_init() which must be
1571 defined in your board-specific files. This option is deprecated
1572 and is only used by novena. For new boards, use driver model
1577 Enable the Freescale DIU video driver. Reference boards for
1578 SOCs that have a DIU should define this macro to enable DIU
1579 support, and should also define these other macros:
1585 CONFIG_VIDEO_SW_CURSOR
1586 CONFIG_VGA_AS_SINGLE_DEVICE
1588 CONFIG_VIDEO_BMP_LOGO
1590 The DIU driver will look for the 'video-mode' environment
1591 variable, and if defined, enable the DIU as a console during
1592 boot. See the documentation file doc/README.video for a
1593 description of this variable.
1595 - LCD Support: CONFIG_LCD
1597 Define this to enable LCD support (for output to LCD
1598 display); also select one of the supported displays
1599 by defining one of these:
1603 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1605 CONFIG_NEC_NL6448AC33:
1607 NEC NL6448AC33-18. Active, color, single scan.
1609 CONFIG_NEC_NL6448BC20
1611 NEC NL6448BC20-08. 6.5", 640x480.
1612 Active, color, single scan.
1614 CONFIG_NEC_NL6448BC33_54
1616 NEC NL6448BC33-54. 10.4", 640x480.
1617 Active, color, single scan.
1621 Sharp 320x240. Active, color, single scan.
1622 It isn't 16x9, and I am not sure what it is.
1624 CONFIG_SHARP_LQ64D341
1626 Sharp LQ64D341 display, 640x480.
1627 Active, color, single scan.
1631 HLD1045 display, 640x480.
1632 Active, color, single scan.
1636 Optrex CBL50840-2 NF-FW 99 22 M5
1638 Hitachi LMG6912RPFC-00T
1642 320x240. Black & white.
1644 Normally display is black on white background; define
1645 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1647 CONFIG_LCD_ALIGNMENT
1649 Normally the LCD is page-aligned (typically 4KB). If this is
1650 defined then the LCD will be aligned to this value instead.
1651 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1652 here, since it is cheaper to change data cache settings on
1653 a per-section basis.
1658 Sometimes, for example if the display is mounted in portrait
1659 mode or even if it's mounted landscape but rotated by 180degree,
1660 we need to rotate our content of the display relative to the
1661 framebuffer, so that user can read the messages which are
1663 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1664 initialized with a given rotation from "vl_rot" out of
1665 "vidinfo_t" which is provided by the board specific code.
1666 The value for vl_rot is coded as following (matching to
1667 fbcon=rotate:<n> linux-kernel commandline):
1668 0 = no rotation respectively 0 degree
1669 1 = 90 degree rotation
1670 2 = 180 degree rotation
1671 3 = 270 degree rotation
1673 If CONFIG_LCD_ROTATION is not defined, the console will be
1674 initialized with 0degree rotation.
1678 Support drawing of RLE8-compressed bitmaps on the LCD.
1682 Enables an 'i2c edid' command which can read EDID
1683 information over I2C from an attached LCD display.
1685 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1687 If this option is set, the environment is checked for
1688 a variable "splashimage". If found, the usual display
1689 of logo, copyright and system information on the LCD
1690 is suppressed and the BMP image at the address
1691 specified in "splashimage" is loaded instead. The
1692 console is redirected to the "nulldev", too. This
1693 allows for a "silent" boot where a splash screen is
1694 loaded very quickly after power-on.
1696 CONFIG_SPLASHIMAGE_GUARD
1698 If this option is set, then U-Boot will prevent the environment
1699 variable "splashimage" from being set to a problematic address
1700 (see doc/README.displaying-bmps).
1701 This option is useful for targets where, due to alignment
1702 restrictions, an improperly aligned BMP image will cause a data
1703 abort. If you think you will not have problems with unaligned
1704 accesses (for example because your toolchain prevents them)
1705 there is no need to set this option.
1707 CONFIG_SPLASH_SCREEN_ALIGN
1709 If this option is set the splash image can be freely positioned
1710 on the screen. Environment variable "splashpos" specifies the
1711 position as "x,y". If a positive number is given it is used as
1712 number of pixel from left/top. If a negative number is given it
1713 is used as number of pixel from right/bottom. You can also
1714 specify 'm' for centering the image.
1717 setenv splashpos m,m
1718 => image at center of screen
1720 setenv splashpos 30,20
1721 => image at x = 30 and y = 20
1723 setenv splashpos -10,m
1724 => vertically centered image
1725 at x = dspWidth - bmpWidth - 9
1727 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1729 If this option is set, additionally to standard BMP
1730 images, gzipped BMP images can be displayed via the
1731 splashscreen support or the bmp command.
1733 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1735 If this option is set, 8-bit RLE compressed BMP images
1736 can be displayed via the splashscreen support or the
1739 - Compression support:
1742 Enabled by default to support gzip compressed images.
1746 If this option is set, support for bzip2 compressed
1747 images is included. If not, only uncompressed and gzip
1748 compressed images are supported.
1750 NOTE: the bzip2 algorithm requires a lot of RAM, so
1751 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1756 If this option is set, support for lzma compressed
1759 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1760 requires an amount of dynamic memory that is given by the
1763 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1765 Where lc and lp stand for, respectively, Literal context bits
1766 and Literal pos bits.
1768 This value is upper-bounded by 14MB in the worst case. Anyway,
1769 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1770 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1771 a very small buffer.
1773 Use the lzmainfo tool to determinate the lc and lp values and
1774 then calculate the amount of needed dynamic memory (ensuring
1775 the appropriate CONFIG_SYS_MALLOC_LEN value).
1779 If this option is set, support for LZO compressed images
1785 The address of PHY on MII bus.
1787 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1789 The clock frequency of the MII bus
1793 If this option is set, support for speed/duplex
1794 detection of gigabit PHY is included.
1796 CONFIG_PHY_RESET_DELAY
1798 Some PHY like Intel LXT971A need extra delay after
1799 reset before any MII register access is possible.
1800 For such PHY, set this option to the usec delay
1801 required. (minimum 300usec for LXT971A)
1803 CONFIG_PHY_CMD_DELAY (ppc4xx)
1805 Some PHY like Intel LXT971A need extra delay after
1806 command issued before MII status register can be read
1811 Define a default value for the IP address to use for
1812 the default Ethernet interface, in case this is not
1813 determined through e.g. bootp.
1814 (Environment variable "ipaddr")
1816 - Server IP address:
1819 Defines a default value for the IP address of a TFTP
1820 server to contact when using the "tftboot" command.
1821 (Environment variable "serverip")
1823 CONFIG_KEEP_SERVERADDR
1825 Keeps the server's MAC address, in the env 'serveraddr'
1826 for passing to bootargs (like Linux's netconsole option)
1828 - Gateway IP address:
1831 Defines a default value for the IP address of the
1832 default router where packets to other networks are
1834 (Environment variable "gatewayip")
1839 Defines a default value for the subnet mask (or
1840 routing prefix) which is used to determine if an IP
1841 address belongs to the local subnet or needs to be
1842 forwarded through a router.
1843 (Environment variable "netmask")
1845 - Multicast TFTP Mode:
1848 Defines whether you want to support multicast TFTP as per
1849 rfc-2090; for example to work with atftp. Lets lots of targets
1850 tftp down the same boot image concurrently. Note: the Ethernet
1851 driver in use must provide a function: mcast() to join/leave a
1854 - BOOTP Recovery Mode:
1855 CONFIG_BOOTP_RANDOM_DELAY
1857 If you have many targets in a network that try to
1858 boot using BOOTP, you may want to avoid that all
1859 systems send out BOOTP requests at precisely the same
1860 moment (which would happen for instance at recovery
1861 from a power failure, when all systems will try to
1862 boot, thus flooding the BOOTP server. Defining
1863 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1864 inserted before sending out BOOTP requests. The
1865 following delays are inserted then:
1867 1st BOOTP request: delay 0 ... 1 sec
1868 2nd BOOTP request: delay 0 ... 2 sec
1869 3rd BOOTP request: delay 0 ... 4 sec
1871 BOOTP requests: delay 0 ... 8 sec
1873 CONFIG_BOOTP_ID_CACHE_SIZE
1875 BOOTP packets are uniquely identified using a 32-bit ID. The
1876 server will copy the ID from client requests to responses and
1877 U-Boot will use this to determine if it is the destination of
1878 an incoming response. Some servers will check that addresses
1879 aren't in use before handing them out (usually using an ARP
1880 ping) and therefore take up to a few hundred milliseconds to
1881 respond. Network congestion may also influence the time it
1882 takes for a response to make it back to the client. If that
1883 time is too long, U-Boot will retransmit requests. In order
1884 to allow earlier responses to still be accepted after these
1885 retransmissions, U-Boot's BOOTP client keeps a small cache of
1886 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1887 cache. The default is to keep IDs for up to four outstanding
1888 requests. Increasing this will allow U-Boot to accept offers
1889 from a BOOTP client in networks with unusually high latency.
1891 - DHCP Advanced Options:
1892 You can fine tune the DHCP functionality by defining
1893 CONFIG_BOOTP_* symbols:
1895 CONFIG_BOOTP_SUBNETMASK
1896 CONFIG_BOOTP_GATEWAY
1897 CONFIG_BOOTP_HOSTNAME
1898 CONFIG_BOOTP_NISDOMAIN
1899 CONFIG_BOOTP_BOOTPATH
1900 CONFIG_BOOTP_BOOTFILESIZE
1903 CONFIG_BOOTP_SEND_HOSTNAME
1904 CONFIG_BOOTP_NTPSERVER
1905 CONFIG_BOOTP_TIMEOFFSET
1906 CONFIG_BOOTP_VENDOREX
1907 CONFIG_BOOTP_MAY_FAIL
1909 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1910 environment variable, not the BOOTP server.
1912 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1913 after the configured retry count, the call will fail
1914 instead of starting over. This can be used to fail over
1915 to Link-local IP address configuration if the DHCP server
1918 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1919 serverip from a DHCP server, it is possible that more
1920 than one DNS serverip is offered to the client.
1921 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1922 serverip will be stored in the additional environment
1923 variable "dnsip2". The first DNS serverip is always
1924 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1927 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1928 to do a dynamic update of a DNS server. To do this, they
1929 need the hostname of the DHCP requester.
1930 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1931 of the "hostname" environment variable is passed as
1932 option 12 to the DHCP server.
1934 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1936 A 32bit value in microseconds for a delay between
1937 receiving a "DHCP Offer" and sending the "DHCP Request".
1938 This fixes a problem with certain DHCP servers that don't
1939 respond 100% of the time to a "DHCP request". E.g. On an
1940 AT91RM9200 processor running at 180MHz, this delay needed
1941 to be *at least* 15,000 usec before a Windows Server 2003
1942 DHCP server would reply 100% of the time. I recommend at
1943 least 50,000 usec to be safe. The alternative is to hope
1944 that one of the retries will be successful but note that
1945 the DHCP timeout and retry process takes a longer than
1948 - Link-local IP address negotiation:
1949 Negotiate with other link-local clients on the local network
1950 for an address that doesn't require explicit configuration.
1951 This is especially useful if a DHCP server cannot be guaranteed
1952 to exist in all environments that the device must operate.
1954 See doc/README.link-local for more information.
1957 CONFIG_CDP_DEVICE_ID
1959 The device id used in CDP trigger frames.
1961 CONFIG_CDP_DEVICE_ID_PREFIX
1963 A two character string which is prefixed to the MAC address
1968 A printf format string which contains the ascii name of
1969 the port. Normally is set to "eth%d" which sets
1970 eth0 for the first Ethernet, eth1 for the second etc.
1972 CONFIG_CDP_CAPABILITIES
1974 A 32bit integer which indicates the device capabilities;
1975 0x00000010 for a normal host which does not forwards.
1979 An ascii string containing the version of the software.
1983 An ascii string containing the name of the platform.
1987 A 32bit integer sent on the trigger.
1989 CONFIG_CDP_POWER_CONSUMPTION
1991 A 16bit integer containing the power consumption of the
1992 device in .1 of milliwatts.
1994 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1996 A byte containing the id of the VLAN.
1998 - Status LED: CONFIG_LED_STATUS
2000 Several configurations allow to display the current
2001 status using a LED. For instance, the LED will blink
2002 fast while running U-Boot code, stop blinking as
2003 soon as a reply to a BOOTP request was received, and
2004 start blinking slow once the Linux kernel is running
2005 (supported by a status LED driver in the Linux
2006 kernel). Defining CONFIG_LED_STATUS enables this
2011 CONFIG_LED_STATUS_GPIO
2012 The status LED can be connected to a GPIO pin.
2013 In such cases, the gpio_led driver can be used as a
2014 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2015 to include the gpio_led driver in the U-Boot binary.
2017 CONFIG_GPIO_LED_INVERTED_TABLE
2018 Some GPIO connected LEDs may have inverted polarity in which
2019 case the GPIO high value corresponds to LED off state and
2020 GPIO low value corresponds to LED on state.
2021 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2022 with a list of GPIO LEDs that have inverted polarity.
2024 - CAN Support: CONFIG_CAN_DRIVER
2026 Defining CONFIG_CAN_DRIVER enables CAN driver support
2027 on those systems that support this (optional)
2028 feature, like the TQM8xxL modules.
2030 - I2C Support: CONFIG_SYS_I2C
2032 This enable the NEW i2c subsystem, and will allow you to use
2033 i2c commands at the u-boot command line (as long as you set
2034 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2035 based realtime clock chips or other i2c devices. See
2036 common/cmd_i2c.c for a description of the command line
2039 ported i2c driver to the new framework:
2040 - drivers/i2c/soft_i2c.c:
2041 - activate first bus with CONFIG_SYS_I2C_SOFT define
2042 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2043 for defining speed and slave address
2044 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2045 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2046 for defining speed and slave address
2047 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2048 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2049 for defining speed and slave address
2050 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2051 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2052 for defining speed and slave address
2054 - drivers/i2c/fsl_i2c.c:
2055 - activate i2c driver with CONFIG_SYS_I2C_FSL
2056 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2057 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2058 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2060 - If your board supports a second fsl i2c bus, define
2061 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2062 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2063 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2066 - drivers/i2c/tegra_i2c.c:
2067 - activate this driver with CONFIG_SYS_I2C_TEGRA
2068 - This driver adds 4 i2c buses with a fix speed from
2069 100000 and the slave addr 0!
2071 - drivers/i2c/ppc4xx_i2c.c
2072 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2073 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2074 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2076 - drivers/i2c/i2c_mxc.c
2077 - activate this driver with CONFIG_SYS_I2C_MXC
2078 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2079 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2080 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2081 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2082 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2083 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2084 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2085 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2086 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2087 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2088 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2089 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2090 If those defines are not set, default value is 100000
2091 for speed, and 0 for slave.
2093 - drivers/i2c/rcar_i2c.c:
2094 - activate this driver with CONFIG_SYS_I2C_RCAR
2095 - This driver adds 4 i2c buses
2097 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2098 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2099 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2100 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2101 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2102 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2103 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2104 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2105 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2107 - drivers/i2c/sh_i2c.c:
2108 - activate this driver with CONFIG_SYS_I2C_SH
2109 - This driver adds from 2 to 5 i2c buses
2111 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2112 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2113 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2114 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2115 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2116 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2117 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2118 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2119 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2120 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2121 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2123 - drivers/i2c/omap24xx_i2c.c
2124 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2125 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2126 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2127 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2128 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2129 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2130 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2131 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2132 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2133 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2134 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2136 - drivers/i2c/zynq_i2c.c
2137 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2138 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2139 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2141 - drivers/i2c/s3c24x0_i2c.c:
2142 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2143 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2144 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2145 with a fix speed from 100000 and the slave addr 0!
2147 - drivers/i2c/ihs_i2c.c
2148 - activate this driver with CONFIG_SYS_I2C_IHS
2149 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2150 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2151 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2152 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2153 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2154 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2155 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2156 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2157 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2158 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2159 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2160 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2161 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2162 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2163 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2164 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2165 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2166 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2167 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2168 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2169 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2173 CONFIG_SYS_NUM_I2C_BUSES
2174 Hold the number of i2c buses you want to use.
2176 CONFIG_SYS_I2C_DIRECT_BUS
2177 define this, if you don't use i2c muxes on your hardware.
2178 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2181 CONFIG_SYS_I2C_MAX_HOPS
2182 define how many muxes are maximal consecutively connected
2183 on one i2c bus. If you not use i2c muxes, omit this
2186 CONFIG_SYS_I2C_BUSES
2187 hold a list of buses you want to use, only used if
2188 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2189 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2190 CONFIG_SYS_NUM_I2C_BUSES = 9:
2192 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2193 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2194 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2195 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2196 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2197 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2198 {1, {I2C_NULL_HOP}}, \
2199 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2200 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2204 bus 0 on adapter 0 without a mux
2205 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2206 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2207 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2208 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2209 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2210 bus 6 on adapter 1 without a mux
2211 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2212 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2214 If you do not have i2c muxes on your board, omit this define.
2216 - Legacy I2C Support: CONFIG_HARD_I2C
2218 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2219 provides the following compelling advantages:
2221 - more than one i2c adapter is usable
2222 - approved multibus support
2223 - better i2c mux support
2225 ** Please consider updating your I2C driver now. **
2227 These enable legacy I2C serial bus commands. Defining
2228 CONFIG_HARD_I2C will include the appropriate I2C driver
2229 for the selected CPU.
2231 This will allow you to use i2c commands at the u-boot
2232 command line (as long as you set CONFIG_CMD_I2C in
2233 CONFIG_COMMANDS) and communicate with i2c based realtime
2234 clock chips. See common/cmd_i2c.c for a description of the
2235 command line interface.
2237 CONFIG_HARD_I2C selects a hardware I2C controller.
2239 There are several other quantities that must also be
2240 defined when you define CONFIG_HARD_I2C.
2242 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2243 to be the frequency (in Hz) at which you wish your i2c bus
2244 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2245 the CPU's i2c node address).
2247 Now, the u-boot i2c code for the mpc8xx
2248 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2249 and so its address should therefore be cleared to 0 (See,
2250 eg, MPC823e User's Manual p.16-473). So, set
2251 CONFIG_SYS_I2C_SLAVE to 0.
2253 CONFIG_SYS_I2C_INIT_MPC5XXX
2255 When a board is reset during an i2c bus transfer
2256 chips might think that the current transfer is still
2257 in progress. Reset the slave devices by sending start
2258 commands until the slave device responds.
2260 That's all that's required for CONFIG_HARD_I2C.
2262 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2263 then the following macros need to be defined (examples are
2264 from include/configs/lwmon.h):
2268 (Optional). Any commands necessary to enable the I2C
2269 controller or configure ports.
2271 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2275 (Only for MPC8260 CPU). The I/O port to use (the code
2276 assumes both bits are on the same port). Valid values
2277 are 0..3 for ports A..D.
2281 The code necessary to make the I2C data line active
2282 (driven). If the data line is open collector, this
2285 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2289 The code necessary to make the I2C data line tri-stated
2290 (inactive). If the data line is open collector, this
2293 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2297 Code that returns true if the I2C data line is high,
2300 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2304 If <bit> is true, sets the I2C data line high. If it
2305 is false, it clears it (low).
2307 eg: #define I2C_SDA(bit) \
2308 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2309 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2313 If <bit> is true, sets the I2C clock line high. If it
2314 is false, it clears it (low).
2316 eg: #define I2C_SCL(bit) \
2317 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2318 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2322 This delay is invoked four times per clock cycle so this
2323 controls the rate of data transfer. The data rate thus
2324 is 1 / (I2C_DELAY * 4). Often defined to be something
2327 #define I2C_DELAY udelay(2)
2329 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2331 If your arch supports the generic GPIO framework (asm/gpio.h),
2332 then you may alternatively define the two GPIOs that are to be
2333 used as SCL / SDA. Any of the previous I2C_xxx macros will
2334 have GPIO-based defaults assigned to them as appropriate.
2336 You should define these to the GPIO value as given directly to
2337 the generic GPIO functions.
2339 CONFIG_SYS_I2C_INIT_BOARD
2341 When a board is reset during an i2c bus transfer
2342 chips might think that the current transfer is still
2343 in progress. On some boards it is possible to access
2344 the i2c SCLK line directly, either by using the
2345 processor pin as a GPIO or by having a second pin
2346 connected to the bus. If this option is defined a
2347 custom i2c_init_board() routine in boards/xxx/board.c
2348 is run early in the boot sequence.
2350 CONFIG_SYS_I2C_BOARD_LATE_INIT
2352 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2353 defined a custom i2c_board_late_init() routine in
2354 boards/xxx/board.c is run AFTER the operations in i2c_init()
2355 is completed. This callpoint can be used to unreset i2c bus
2356 using CPU i2c controller register accesses for CPUs whose i2c
2357 controller provide such a method. It is called at the end of
2358 i2c_init() to allow i2c_init operations to setup the i2c bus
2359 controller on the CPU (e.g. setting bus speed & slave address).
2361 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2363 This option enables configuration of bi_iic_fast[] flags
2364 in u-boot bd_info structure based on u-boot environment
2365 variable "i2cfast". (see also i2cfast)
2367 CONFIG_I2C_MULTI_BUS
2369 This option allows the use of multiple I2C buses, each of which
2370 must have a controller. At any point in time, only one bus is
2371 active. To switch to a different bus, use the 'i2c dev' command.
2372 Note that bus numbering is zero-based.
2374 CONFIG_SYS_I2C_NOPROBES
2376 This option specifies a list of I2C devices that will be skipped
2377 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2378 is set, specify a list of bus-device pairs. Otherwise, specify
2379 a 1D array of device addresses
2382 #undef CONFIG_I2C_MULTI_BUS
2383 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2385 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2387 #define CONFIG_I2C_MULTI_BUS
2388 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2390 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2392 CONFIG_SYS_SPD_BUS_NUM
2394 If defined, then this indicates the I2C bus number for DDR SPD.
2395 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2397 CONFIG_SYS_RTC_BUS_NUM
2399 If defined, then this indicates the I2C bus number for the RTC.
2400 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2402 CONFIG_SYS_DTT_BUS_NUM
2404 If defined, then this indicates the I2C bus number for the DTT.
2405 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2407 CONFIG_SYS_I2C_DTT_ADDR:
2409 If defined, specifies the I2C address of the DTT device.
2410 If not defined, then U-Boot uses predefined value for
2411 specified DTT device.
2413 CONFIG_SOFT_I2C_READ_REPEATED_START
2415 defining this will force the i2c_read() function in
2416 the soft_i2c driver to perform an I2C repeated start
2417 between writing the address pointer and reading the
2418 data. If this define is omitted the default behaviour
2419 of doing a stop-start sequence will be used. Most I2C
2420 devices can use either method, but some require one or
2423 - SPI Support: CONFIG_SPI
2425 Enables SPI driver (so far only tested with
2426 SPI EEPROM, also an instance works with Crystal A/D and
2427 D/As on the SACSng board)
2431 Enables the driver for SPI controller on SuperH. Currently
2432 only SH7757 is supported.
2436 Enables a software (bit-bang) SPI driver rather than
2437 using hardware support. This is a general purpose
2438 driver that only requires three general I/O port pins
2439 (two outputs, one input) to function. If this is
2440 defined, the board configuration must define several
2441 SPI configuration items (port pins to use, etc). For
2442 an example, see include/configs/sacsng.h.
2446 Enables a hardware SPI driver for general-purpose reads
2447 and writes. As with CONFIG_SOFT_SPI, the board configuration
2448 must define a list of chip-select function pointers.
2449 Currently supported on some MPC8xxx processors. For an
2450 example, see include/configs/mpc8349emds.h.
2454 Enables the driver for the SPI controllers on i.MX and MXC
2455 SoCs. Currently i.MX31/35/51 are supported.
2457 CONFIG_SYS_SPI_MXC_WAIT
2458 Timeout for waiting until spi transfer completed.
2459 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2461 - FPGA Support: CONFIG_FPGA
2463 Enables FPGA subsystem.
2465 CONFIG_FPGA_<vendor>
2467 Enables support for specific chip vendors.
2470 CONFIG_FPGA_<family>
2472 Enables support for FPGA family.
2473 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2477 Specify the number of FPGA devices to support.
2479 CONFIG_CMD_FPGA_LOADMK
2481 Enable support for fpga loadmk command
2483 CONFIG_CMD_FPGA_LOADP
2485 Enable support for fpga loadp command - load partial bitstream
2487 CONFIG_CMD_FPGA_LOADBP
2489 Enable support for fpga loadbp command - load partial bitstream
2492 CONFIG_SYS_FPGA_PROG_FEEDBACK
2494 Enable printing of hash marks during FPGA configuration.
2496 CONFIG_SYS_FPGA_CHECK_BUSY
2498 Enable checks on FPGA configuration interface busy
2499 status by the configuration function. This option
2500 will require a board or device specific function to
2505 If defined, a function that provides delays in the FPGA
2506 configuration driver.
2508 CONFIG_SYS_FPGA_CHECK_CTRLC
2509 Allow Control-C to interrupt FPGA configuration
2511 CONFIG_SYS_FPGA_CHECK_ERROR
2513 Check for configuration errors during FPGA bitfile
2514 loading. For example, abort during Virtex II
2515 configuration if the INIT_B line goes low (which
2516 indicated a CRC error).
2518 CONFIG_SYS_FPGA_WAIT_INIT
2520 Maximum time to wait for the INIT_B line to de-assert
2521 after PROB_B has been de-asserted during a Virtex II
2522 FPGA configuration sequence. The default time is 500
2525 CONFIG_SYS_FPGA_WAIT_BUSY
2527 Maximum time to wait for BUSY to de-assert during
2528 Virtex II FPGA configuration. The default is 5 ms.
2530 CONFIG_SYS_FPGA_WAIT_CONFIG
2532 Time to wait after FPGA configuration. The default is
2535 - Configuration Management:
2538 Some SoCs need special image types (e.g. U-Boot binary
2539 with a special header) as build targets. By defining
2540 CONFIG_BUILD_TARGET in the SoC / board header, this
2541 special image will be automatically built upon calling
2546 If defined, this string will be added to the U-Boot
2547 version information (U_BOOT_VERSION)
2549 - Vendor Parameter Protection:
2551 U-Boot considers the values of the environment
2552 variables "serial#" (Board Serial Number) and
2553 "ethaddr" (Ethernet Address) to be parameters that
2554 are set once by the board vendor / manufacturer, and
2555 protects these variables from casual modification by
2556 the user. Once set, these variables are read-only,
2557 and write or delete attempts are rejected. You can
2558 change this behaviour:
2560 If CONFIG_ENV_OVERWRITE is #defined in your config
2561 file, the write protection for vendor parameters is
2562 completely disabled. Anybody can change or delete
2565 Alternatively, if you define _both_ an ethaddr in the
2566 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2567 Ethernet address is installed in the environment,
2568 which can be changed exactly ONCE by the user. [The
2569 serial# is unaffected by this, i. e. it remains
2572 The same can be accomplished in a more flexible way
2573 for any variable by configuring the type of access
2574 to allow for those variables in the ".flags" variable
2575 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2580 Define this variable to enable the reservation of
2581 "protected RAM", i. e. RAM which is not overwritten
2582 by U-Boot. Define CONFIG_PRAM to hold the number of
2583 kB you want to reserve for pRAM. You can overwrite
2584 this default value by defining an environment
2585 variable "pram" to the number of kB you want to
2586 reserve. Note that the board info structure will
2587 still show the full amount of RAM. If pRAM is
2588 reserved, a new environment variable "mem" will
2589 automatically be defined to hold the amount of
2590 remaining RAM in a form that can be passed as boot
2591 argument to Linux, for instance like that:
2593 setenv bootargs ... mem=\${mem}
2596 This way you can tell Linux not to use this memory,
2597 either, which results in a memory region that will
2598 not be affected by reboots.
2600 *WARNING* If your board configuration uses automatic
2601 detection of the RAM size, you must make sure that
2602 this memory test is non-destructive. So far, the
2603 following board configurations are known to be
2606 IVMS8, IVML24, SPD8xx, TQM8xxL,
2607 HERMES, IP860, RPXlite, LWMON,
2610 - Access to physical memory region (> 4GB)
2611 Some basic support is provided for operations on memory not
2612 normally accessible to U-Boot - e.g. some architectures
2613 support access to more than 4GB of memory on 32-bit
2614 machines using physical address extension or similar.
2615 Define CONFIG_PHYSMEM to access this basic support, which
2616 currently only supports clearing the memory.
2621 Define this variable to stop the system in case of a
2622 fatal error, so that you have to reset it manually.
2623 This is probably NOT a good idea for an embedded
2624 system where you want the system to reboot
2625 automatically as fast as possible, but it may be
2626 useful during development since you can try to debug
2627 the conditions that lead to the situation.
2629 CONFIG_NET_RETRY_COUNT
2631 This variable defines the number of retries for
2632 network operations like ARP, RARP, TFTP, or BOOTP
2633 before giving up the operation. If not defined, a
2634 default value of 5 is used.
2638 Timeout waiting for an ARP reply in milliseconds.
2642 Timeout in milliseconds used in NFS protocol.
2643 If you encounter "ERROR: Cannot umount" in nfs command,
2644 try longer timeout such as
2645 #define CONFIG_NFS_TIMEOUT 10000UL
2647 - Command Interpreter:
2648 CONFIG_AUTO_COMPLETE
2650 Enable auto completion of commands using TAB.
2652 CONFIG_SYS_PROMPT_HUSH_PS2
2654 This defines the secondary prompt string, which is
2655 printed when the command interpreter needs more input
2656 to complete a command. Usually "> ".
2660 In the current implementation, the local variables
2661 space and global environment variables space are
2662 separated. Local variables are those you define by
2663 simply typing `name=value'. To access a local
2664 variable later on, you have write `$name' or
2665 `${name}'; to execute the contents of a variable
2666 directly type `$name' at the command prompt.
2668 Global environment variables are those you use
2669 setenv/printenv to work with. To run a command stored
2670 in such a variable, you need to use the run command,
2671 and you must not use the '$' sign to access them.
2673 To store commands and special characters in a
2674 variable, please use double quotation marks
2675 surrounding the whole text of the variable, instead
2676 of the backslashes before semicolons and special
2679 - Command Line Editing and History:
2680 CONFIG_CMDLINE_EDITING
2682 Enable editing and History functions for interactive
2683 command line input operations
2685 - Command Line PS1/PS2 support:
2686 CONFIG_CMDLINE_PS_SUPPORT
2688 Enable support for changing the command prompt string
2689 at run-time. Only static string is supported so far.
2690 The string is obtained from environment variables PS1
2693 - Default Environment:
2694 CONFIG_EXTRA_ENV_SETTINGS
2696 Define this to contain any number of null terminated
2697 strings (variable = value pairs) that will be part of
2698 the default environment compiled into the boot image.
2700 For example, place something like this in your
2701 board's config file:
2703 #define CONFIG_EXTRA_ENV_SETTINGS \
2707 Warning: This method is based on knowledge about the
2708 internal format how the environment is stored by the
2709 U-Boot code. This is NOT an official, exported
2710 interface! Although it is unlikely that this format
2711 will change soon, there is no guarantee either.
2712 You better know what you are doing here.
2714 Note: overly (ab)use of the default environment is
2715 discouraged. Make sure to check other ways to preset
2716 the environment like the "source" command or the
2719 CONFIG_ENV_VARS_UBOOT_CONFIG
2721 Define this in order to add variables describing the
2722 U-Boot build configuration to the default environment.
2723 These will be named arch, cpu, board, vendor, and soc.
2725 Enabling this option will cause the following to be defined:
2733 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2735 Define this in order to add variables describing certain
2736 run-time determined information about the hardware to the
2737 environment. These will be named board_name, board_rev.
2739 CONFIG_DELAY_ENVIRONMENT
2741 Normally the environment is loaded when the board is
2742 initialised so that it is available to U-Boot. This inhibits
2743 that so that the environment is not available until
2744 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2745 this is instead controlled by the value of
2746 /config/load-environment.
2748 - DataFlash Support:
2749 CONFIG_HAS_DATAFLASH
2751 Defining this option enables DataFlash features and
2752 allows to read/write in Dataflash via the standard
2755 - Serial Flash support
2758 Defining this option enables SPI flash commands
2759 'sf probe/read/write/erase/update'.
2761 Usage requires an initial 'probe' to define the serial
2762 flash parameters, followed by read/write/erase/update
2765 The following defaults may be provided by the platform
2766 to handle the common case when only a single serial
2767 flash is present on the system.
2769 CONFIG_SF_DEFAULT_BUS Bus identifier
2770 CONFIG_SF_DEFAULT_CS Chip-select
2771 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2772 CONFIG_SF_DEFAULT_SPEED in Hz
2776 Define this option to include a destructive SPI flash
2779 CONFIG_SF_DUAL_FLASH Dual flash memories
2781 Define this option to use dual flash support where two flash
2782 memories can be connected with a given cs line.
2783 Currently Xilinx Zynq qspi supports these type of connections.
2785 - SystemACE Support:
2788 Adding this option adds support for Xilinx SystemACE
2789 chips attached via some sort of local bus. The address
2790 of the chip must also be defined in the
2791 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2793 #define CONFIG_SYSTEMACE
2794 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2796 When SystemACE support is added, the "ace" device type
2797 becomes available to the fat commands, i.e. fatls.
2799 - TFTP Fixed UDP Port:
2802 If this is defined, the environment variable tftpsrcp
2803 is used to supply the TFTP UDP source port value.
2804 If tftpsrcp isn't defined, the normal pseudo-random port
2805 number generator is used.
2807 Also, the environment variable tftpdstp is used to supply
2808 the TFTP UDP destination port value. If tftpdstp isn't
2809 defined, the normal port 69 is used.
2811 The purpose for tftpsrcp is to allow a TFTP server to
2812 blindly start the TFTP transfer using the pre-configured
2813 target IP address and UDP port. This has the effect of
2814 "punching through" the (Windows XP) firewall, allowing
2815 the remainder of the TFTP transfer to proceed normally.
2816 A better solution is to properly configure the firewall,
2817 but sometimes that is not allowed.
2822 This enables a generic 'hash' command which can produce
2823 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2827 Enable the hash verify command (hash -v). This adds to code
2830 CONFIG_SHA1 - This option enables support of hashing using SHA1
2831 algorithm. The hash is calculated in software.
2832 CONFIG_SHA256 - This option enables support of hashing using
2833 SHA256 algorithm. The hash is calculated in software.
2834 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2835 for SHA1/SHA256 hashing.
2836 This affects the 'hash' command and also the
2837 hash_lookup_algo() function.
2838 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2839 hardware-acceleration for SHA1/SHA256 progressive hashing.
2840 Data can be streamed in a block at a time and the hashing
2841 is performed in hardware.
2843 Note: There is also a sha1sum command, which should perhaps
2844 be deprecated in favour of 'hash sha1'.
2846 - Freescale i.MX specific commands:
2847 CONFIG_CMD_HDMIDETECT
2848 This enables 'hdmidet' command which returns true if an
2849 HDMI monitor is detected. This command is i.MX 6 specific.
2852 This enables the 'bmode' (bootmode) command for forcing
2853 a boot from specific media.
2855 This is useful for forcing the ROM's usb downloader to
2856 activate upon a watchdog reset which is nice when iterating
2857 on U-Boot. Using the reset button or running bmode normal
2858 will set it back to normal. This command currently
2859 supports i.MX53 and i.MX6.
2861 - bootcount support:
2862 CONFIG_BOOTCOUNT_LIMIT
2864 This enables the bootcounter support, see:
2865 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2868 enable special bootcounter support on at91sam9xe based boards.
2870 enable special bootcounter support on da850 based boards.
2871 CONFIG_BOOTCOUNT_RAM
2872 enable support for the bootcounter in RAM
2873 CONFIG_BOOTCOUNT_I2C
2874 enable support for the bootcounter on an i2c (like RTC) device.
2875 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2876 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2878 CONFIG_BOOTCOUNT_ALEN = address len
2880 - Show boot progress:
2881 CONFIG_SHOW_BOOT_PROGRESS
2883 Defining this option allows to add some board-
2884 specific code (calling a user-provided function
2885 "show_boot_progress(int)") that enables you to show
2886 the system's boot progress on some display (for
2887 example, some LED's) on your board. At the moment,
2888 the following checkpoints are implemented:
2891 Legacy uImage format:
2894 1 common/cmd_bootm.c before attempting to boot an image
2895 -1 common/cmd_bootm.c Image header has bad magic number
2896 2 common/cmd_bootm.c Image header has correct magic number
2897 -2 common/cmd_bootm.c Image header has bad checksum
2898 3 common/cmd_bootm.c Image header has correct checksum
2899 -3 common/cmd_bootm.c Image data has bad checksum
2900 4 common/cmd_bootm.c Image data has correct checksum
2901 -4 common/cmd_bootm.c Image is for unsupported architecture
2902 5 common/cmd_bootm.c Architecture check OK
2903 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2904 6 common/cmd_bootm.c Image Type check OK
2905 -6 common/cmd_bootm.c gunzip uncompression error
2906 -7 common/cmd_bootm.c Unimplemented compression type
2907 7 common/cmd_bootm.c Uncompression OK
2908 8 common/cmd_bootm.c No uncompress/copy overwrite error
2909 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2911 9 common/image.c Start initial ramdisk verification
2912 -10 common/image.c Ramdisk header has bad magic number
2913 -11 common/image.c Ramdisk header has bad checksum
2914 10 common/image.c Ramdisk header is OK
2915 -12 common/image.c Ramdisk data has bad checksum
2916 11 common/image.c Ramdisk data has correct checksum
2917 12 common/image.c Ramdisk verification complete, start loading
2918 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2919 13 common/image.c Start multifile image verification
2920 14 common/image.c No initial ramdisk, no multifile, continue.
2922 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2924 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2925 -31 post/post.c POST test failed, detected by post_output_backlog()
2926 -32 post/post.c POST test failed, detected by post_run_single()
2928 34 common/cmd_doc.c before loading a Image from a DOC device
2929 -35 common/cmd_doc.c Bad usage of "doc" command
2930 35 common/cmd_doc.c correct usage of "doc" command
2931 -36 common/cmd_doc.c No boot device
2932 36 common/cmd_doc.c correct boot device
2933 -37 common/cmd_doc.c Unknown Chip ID on boot device
2934 37 common/cmd_doc.c correct chip ID found, device available
2935 -38 common/cmd_doc.c Read Error on boot device
2936 38 common/cmd_doc.c reading Image header from DOC device OK
2937 -39 common/cmd_doc.c Image header has bad magic number
2938 39 common/cmd_doc.c Image header has correct magic number
2939 -40 common/cmd_doc.c Error reading Image from DOC device
2940 40 common/cmd_doc.c Image header has correct magic number
2941 41 common/cmd_ide.c before loading a Image from a IDE device
2942 -42 common/cmd_ide.c Bad usage of "ide" command
2943 42 common/cmd_ide.c correct usage of "ide" command
2944 -43 common/cmd_ide.c No boot device
2945 43 common/cmd_ide.c boot device found
2946 -44 common/cmd_ide.c Device not available
2947 44 common/cmd_ide.c Device available
2948 -45 common/cmd_ide.c wrong partition selected
2949 45 common/cmd_ide.c partition selected
2950 -46 common/cmd_ide.c Unknown partition table
2951 46 common/cmd_ide.c valid partition table found
2952 -47 common/cmd_ide.c Invalid partition type
2953 47 common/cmd_ide.c correct partition type
2954 -48 common/cmd_ide.c Error reading Image Header on boot device
2955 48 common/cmd_ide.c reading Image Header from IDE device OK
2956 -49 common/cmd_ide.c Image header has bad magic number
2957 49 common/cmd_ide.c Image header has correct magic number
2958 -50 common/cmd_ide.c Image header has bad checksum
2959 50 common/cmd_ide.c Image header has correct checksum
2960 -51 common/cmd_ide.c Error reading Image from IDE device
2961 51 common/cmd_ide.c reading Image from IDE device OK
2962 52 common/cmd_nand.c before loading a Image from a NAND device
2963 -53 common/cmd_nand.c Bad usage of "nand" command
2964 53 common/cmd_nand.c correct usage of "nand" command
2965 -54 common/cmd_nand.c No boot device
2966 54 common/cmd_nand.c boot device found
2967 -55 common/cmd_nand.c Unknown Chip ID on boot device
2968 55 common/cmd_nand.c correct chip ID found, device available
2969 -56 common/cmd_nand.c Error reading Image Header on boot device
2970 56 common/cmd_nand.c reading Image Header from NAND device OK
2971 -57 common/cmd_nand.c Image header has bad magic number
2972 57 common/cmd_nand.c Image header has correct magic number
2973 -58 common/cmd_nand.c Error reading Image from NAND device
2974 58 common/cmd_nand.c reading Image from NAND device OK
2976 -60 common/env_common.c Environment has a bad CRC, using default
2978 64 net/eth.c starting with Ethernet configuration.
2979 -64 net/eth.c no Ethernet found.
2980 65 net/eth.c Ethernet found.
2982 -80 common/cmd_net.c usage wrong
2983 80 common/cmd_net.c before calling net_loop()
2984 -81 common/cmd_net.c some error in net_loop() occurred
2985 81 common/cmd_net.c net_loop() back without error
2986 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2987 82 common/cmd_net.c trying automatic boot
2988 83 common/cmd_net.c running "source" command
2989 -83 common/cmd_net.c some error in automatic boot or "source" command
2990 84 common/cmd_net.c end without errors
2995 100 common/cmd_bootm.c Kernel FIT Image has correct format
2996 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2997 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2998 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2999 102 common/cmd_bootm.c Kernel unit name specified
3000 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3001 103 common/cmd_bootm.c Found configuration node
3002 104 common/cmd_bootm.c Got kernel subimage node offset
3003 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3004 105 common/cmd_bootm.c Kernel subimage hash verification OK
3005 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3006 106 common/cmd_bootm.c Architecture check OK
3007 -106 common/cmd_bootm.c Kernel subimage has wrong type
3008 107 common/cmd_bootm.c Kernel subimage type OK
3009 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3010 108 common/cmd_bootm.c Got kernel subimage data/size
3011 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3012 -109 common/cmd_bootm.c Can't get kernel subimage type
3013 -110 common/cmd_bootm.c Can't get kernel subimage comp
3014 -111 common/cmd_bootm.c Can't get kernel subimage os
3015 -112 common/cmd_bootm.c Can't get kernel subimage load address
3016 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3018 120 common/image.c Start initial ramdisk verification
3019 -120 common/image.c Ramdisk FIT image has incorrect format
3020 121 common/image.c Ramdisk FIT image has correct format
3021 122 common/image.c No ramdisk subimage unit name, using configuration
3022 -122 common/image.c Can't get configuration for ramdisk subimage
3023 123 common/image.c Ramdisk unit name specified
3024 -124 common/image.c Can't get ramdisk subimage node offset
3025 125 common/image.c Got ramdisk subimage node offset
3026 -125 common/image.c Ramdisk subimage hash verification failed
3027 126 common/image.c Ramdisk subimage hash verification OK
3028 -126 common/image.c Ramdisk subimage for unsupported architecture
3029 127 common/image.c Architecture check OK
3030 -127 common/image.c Can't get ramdisk subimage data/size
3031 128 common/image.c Got ramdisk subimage data/size
3032 129 common/image.c Can't get ramdisk load address
3033 -129 common/image.c Got ramdisk load address
3035 -130 common/cmd_doc.c Incorrect FIT image format
3036 131 common/cmd_doc.c FIT image format OK
3038 -140 common/cmd_ide.c Incorrect FIT image format
3039 141 common/cmd_ide.c FIT image format OK
3041 -150 common/cmd_nand.c Incorrect FIT image format
3042 151 common/cmd_nand.c FIT image format OK
3044 - legacy image format:
3045 CONFIG_IMAGE_FORMAT_LEGACY
3046 enables the legacy image format support in U-Boot.
3049 enabled if CONFIG_FIT_SIGNATURE is not defined.
3051 CONFIG_DISABLE_IMAGE_LEGACY
3052 disable the legacy image format
3054 This define is introduced, as the legacy image format is
3055 enabled per default for backward compatibility.
3057 - FIT image support:
3058 CONFIG_FIT_DISABLE_SHA256
3059 Supporting SHA256 hashes has quite an impact on binary size.
3060 For constrained systems sha256 hash support can be disabled
3063 TODO(sjg@chromium.org): Adjust this option to be positive,
3064 and move it to Kconfig
3066 - Standalone program support:
3067 CONFIG_STANDALONE_LOAD_ADDR
3069 This option defines a board specific value for the
3070 address where standalone program gets loaded, thus
3071 overwriting the architecture dependent default
3074 - Frame Buffer Address:
3077 Define CONFIG_FB_ADDR if you want to use specific
3078 address for frame buffer. This is typically the case
3079 when using a graphics controller has separate video
3080 memory. U-Boot will then place the frame buffer at
3081 the given address instead of dynamically reserving it
3082 in system RAM by calling lcd_setmem(), which grabs
3083 the memory for the frame buffer depending on the
3084 configured panel size.
3086 Please see board_init_f function.
3088 - Automatic software updates via TFTP server
3090 CONFIG_UPDATE_TFTP_CNT_MAX
3091 CONFIG_UPDATE_TFTP_MSEC_MAX
3093 These options enable and control the auto-update feature;
3094 for a more detailed description refer to doc/README.update.
3096 - MTD Support (mtdparts command, UBI support)
3099 Adds the MTD device infrastructure from the Linux kernel.
3100 Needed for mtdparts command support.
3102 CONFIG_MTD_PARTITIONS
3104 Adds the MTD partitioning infrastructure from the Linux
3105 kernel. Needed for UBI support.
3110 Adds commands for interacting with MTD partitions formatted
3111 with the UBI flash translation layer
3113 Requires also defining CONFIG_RBTREE
3115 CONFIG_UBI_SILENCE_MSG
3117 Make the verbose messages from UBI stop printing. This leaves
3118 warnings and errors enabled.
3121 CONFIG_MTD_UBI_WL_THRESHOLD
3122 This parameter defines the maximum difference between the highest
3123 erase counter value and the lowest erase counter value of eraseblocks
3124 of UBI devices. When this threshold is exceeded, UBI starts performing
3125 wear leveling by means of moving data from eraseblock with low erase
3126 counter to eraseblocks with high erase counter.
3128 The default value should be OK for SLC NAND flashes, NOR flashes and
3129 other flashes which have eraseblock life-cycle 100000 or more.
3130 However, in case of MLC NAND flashes which typically have eraseblock
3131 life-cycle less than 10000, the threshold should be lessened (e.g.,
3132 to 128 or 256, although it does not have to be power of 2).
3136 CONFIG_MTD_UBI_BEB_LIMIT
3137 This option specifies the maximum bad physical eraseblocks UBI
3138 expects on the MTD device (per 1024 eraseblocks). If the
3139 underlying flash does not admit of bad eraseblocks (e.g. NOR
3140 flash), this value is ignored.
3142 NAND datasheets often specify the minimum and maximum NVM
3143 (Number of Valid Blocks) for the flashes' endurance lifetime.
3144 The maximum expected bad eraseblocks per 1024 eraseblocks
3145 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3146 which gives 20 for most NANDs (MaxNVB is basically the total
3147 count of eraseblocks on the chip).
3149 To put it differently, if this value is 20, UBI will try to
3150 reserve about 1.9% of physical eraseblocks for bad blocks
3151 handling. And that will be 1.9% of eraseblocks on the entire
3152 NAND chip, not just the MTD partition UBI attaches. This means
3153 that if you have, say, a NAND flash chip admits maximum 40 bad
3154 eraseblocks, and it is split on two MTD partitions of the same
3155 size, UBI will reserve 40 eraseblocks when attaching a
3160 CONFIG_MTD_UBI_FASTMAP
3161 Fastmap is a mechanism which allows attaching an UBI device
3162 in nearly constant time. Instead of scanning the whole MTD device it
3163 only has to locate a checkpoint (called fastmap) on the device.
3164 The on-flash fastmap contains all information needed to attach
3165 the device. Using fastmap makes only sense on large devices where
3166 attaching by scanning takes long. UBI will not automatically install
3167 a fastmap on old images, but you can set the UBI parameter
3168 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3169 that fastmap-enabled images are still usable with UBI implementations
3170 without fastmap support. On typical flash devices the whole fastmap
3171 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3173 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3174 Set this parameter to enable fastmap automatically on images
3178 CONFIG_MTD_UBI_FM_DEBUG
3179 Enable UBI fastmap debug
3185 Adds commands for interacting with UBI volumes formatted as
3186 UBIFS. UBIFS is read-only in u-boot.
3188 Requires UBI support as well as CONFIG_LZO
3190 CONFIG_UBIFS_SILENCE_MSG
3192 Make the verbose messages from UBIFS stop printing. This leaves
3193 warnings and errors enabled.
3197 Enable building of SPL globally.
3200 LDSCRIPT for linking the SPL binary.
3202 CONFIG_SPL_MAX_FOOTPRINT
3203 Maximum size in memory allocated to the SPL, BSS included.
3204 When defined, the linker checks that the actual memory
3205 used by SPL from _start to __bss_end does not exceed it.
3206 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3207 must not be both defined at the same time.
3210 Maximum size of the SPL image (text, data, rodata, and
3211 linker lists sections), BSS excluded.
3212 When defined, the linker checks that the actual size does
3215 CONFIG_SPL_TEXT_BASE
3216 TEXT_BASE for linking the SPL binary.
3218 CONFIG_SPL_RELOC_TEXT_BASE
3219 Address to relocate to. If unspecified, this is equal to
3220 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3222 CONFIG_SPL_BSS_START_ADDR
3223 Link address for the BSS within the SPL binary.
3225 CONFIG_SPL_BSS_MAX_SIZE
3226 Maximum size in memory allocated to the SPL BSS.
3227 When defined, the linker checks that the actual memory used
3228 by SPL from __bss_start to __bss_end does not exceed it.
3229 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3230 must not be both defined at the same time.
3233 Adress of the start of the stack SPL will use
3235 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3236 When defined, SPL will panic() if the image it has
3237 loaded does not have a signature.
3238 Defining this is useful when code which loads images
3239 in SPL cannot guarantee that absolutely all read errors
3241 An example is the LPC32XX MLC NAND driver, which will
3242 consider that a completely unreadable NAND block is bad,
3243 and thus should be skipped silently.
3245 CONFIG_SPL_RELOC_STACK
3246 Adress of the start of the stack SPL will use after
3247 relocation. If unspecified, this is equal to
3250 CONFIG_SYS_SPL_MALLOC_START
3251 Starting address of the malloc pool used in SPL.
3252 When this option is set the full malloc is used in SPL and
3253 it is set up by spl_init() and before that, the simple malloc()
3254 can be used if CONFIG_SYS_MALLOC_F is defined.
3256 CONFIG_SYS_SPL_MALLOC_SIZE
3257 The size of the malloc pool used in SPL.
3259 CONFIG_SPL_FRAMEWORK
3260 Enable the SPL framework under common/. This framework
3261 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3262 NAND loading of the Linux Kernel.
3265 Enable booting directly to an OS from SPL.
3266 See also: doc/README.falcon
3268 CONFIG_SPL_DISPLAY_PRINT
3269 For ARM, enable an optional function to print more information
3270 about the running system.
3272 CONFIG_SPL_INIT_MINIMAL
3273 Arch init code should be built for a very small image
3275 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3276 Partition on the MMC to load U-Boot from when the MMC is being
3279 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3280 Sector to load kernel uImage from when MMC is being
3281 used in raw mode (for Falcon mode)
3283 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3284 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3285 Sector and number of sectors to load kernel argument
3286 parameters from when MMC is being used in raw mode
3289 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3290 Partition on the MMC to load U-Boot from when the MMC is being
3293 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3294 Filename to read to load U-Boot when reading from filesystem
3296 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3297 Filename to read to load kernel uImage when reading
3298 from filesystem (for Falcon mode)
3300 CONFIG_SPL_FS_LOAD_ARGS_NAME
3301 Filename to read to load kernel argument parameters
3302 when reading from filesystem (for Falcon mode)
3304 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3305 Set this for NAND SPL on PPC mpc83xx targets, so that
3306 start.S waits for the rest of the SPL to load before
3307 continuing (the hardware starts execution after just
3308 loading the first page rather than the full 4K).
3310 CONFIG_SPL_SKIP_RELOCATE
3311 Avoid SPL relocation
3313 CONFIG_SPL_NAND_BASE
3314 Include nand_base.c in the SPL. Requires
3315 CONFIG_SPL_NAND_DRIVERS.
3317 CONFIG_SPL_NAND_DRIVERS
3318 SPL uses normal NAND drivers, not minimal drivers.
3321 Include standard software ECC in the SPL
3323 CONFIG_SPL_NAND_SIMPLE
3324 Support for NAND boot using simple NAND drivers that
3325 expose the cmd_ctrl() interface.
3328 Support for a lightweight UBI (fastmap) scanner and
3331 CONFIG_SPL_NAND_RAW_ONLY
3332 Support to boot only raw u-boot.bin images. Use this only
3333 if you need to save space.
3335 CONFIG_SPL_COMMON_INIT_DDR
3336 Set for common ddr init with serial presence detect in
3339 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3340 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3341 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3342 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3343 CONFIG_SYS_NAND_ECCBYTES
3344 Defines the size and behavior of the NAND that SPL uses
3347 CONFIG_SPL_NAND_BOOT
3348 Add support NAND boot
3350 CONFIG_SYS_NAND_U_BOOT_OFFS
3351 Location in NAND to read U-Boot from
3353 CONFIG_SYS_NAND_U_BOOT_DST
3354 Location in memory to load U-Boot to
3356 CONFIG_SYS_NAND_U_BOOT_SIZE
3357 Size of image to load
3359 CONFIG_SYS_NAND_U_BOOT_START
3360 Entry point in loaded image to jump to
3362 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3363 Define this if you need to first read the OOB and then the
3364 data. This is used, for example, on davinci platforms.
3366 CONFIG_SPL_OMAP3_ID_NAND
3367 Support for an OMAP3-specific set of functions to return the
3368 ID and MFR of the first attached NAND chip, if present.
3370 CONFIG_SPL_RAM_DEVICE
3371 Support for running image already present in ram, in SPL binary
3374 Image offset to which the SPL should be padded before appending
3375 the SPL payload. By default, this is defined as
3376 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3377 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3378 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3381 Final target image containing SPL and payload. Some SPLs
3382 use an arch-specific makefile fragment instead, for
3383 example if more than one image needs to be produced.
3385 CONFIG_FIT_SPL_PRINT
3386 Printing information about a FIT image adds quite a bit of
3387 code to SPL. So this is normally disabled in SPL. Use this
3388 option to re-enable it. This will affect the output of the
3389 bootm command when booting a FIT image.
3393 Enable building of TPL globally.
3396 Image offset to which the TPL should be padded before appending
3397 the TPL payload. By default, this is defined as
3398 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3399 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3400 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3402 - Interrupt support (PPC):
3404 There are common interrupt_init() and timer_interrupt()
3405 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3406 for CPU specific initialization. interrupt_init_cpu()
3407 should set decrementer_count to appropriate value. If
3408 CPU resets decrementer automatically after interrupt
3409 (ppc4xx) it should set decrementer_count to zero.
3410 timer_interrupt() calls timer_interrupt_cpu() for CPU
3411 specific handling. If board has watchdog / status_led
3412 / other_activity_monitor it works automatically from
3413 general timer_interrupt().
3416 Board initialization settings:
3417 ------------------------------
3419 During Initialization u-boot calls a number of board specific functions
3420 to allow the preparation of board specific prerequisites, e.g. pin setup
3421 before drivers are initialized. To enable these callbacks the
3422 following configuration macros have to be defined. Currently this is
3423 architecture specific, so please check arch/your_architecture/lib/board.c
3424 typically in board_init_f() and board_init_r().
3426 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3427 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3428 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3429 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3431 Configuration Settings:
3432 -----------------------
3434 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3435 Optionally it can be defined to support 64-bit memory commands.
3437 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3438 undefine this when you're short of memory.
3440 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3441 width of the commands listed in the 'help' command output.
3443 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3444 prompt for user input.
3446 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3448 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3450 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3452 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3453 the application (usually a Linux kernel) when it is
3456 - CONFIG_SYS_BAUDRATE_TABLE:
3457 List of legal baudrate settings for this board.
3459 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3460 Begin and End addresses of the area used by the
3463 - CONFIG_SYS_ALT_MEMTEST:
3464 Enable an alternate, more extensive memory test.
3466 - CONFIG_SYS_MEMTEST_SCRATCH:
3467 Scratch address used by the alternate memory test
3468 You only need to set this if address zero isn't writeable
3470 - CONFIG_SYS_MEM_RESERVE_SECURE
3471 Only implemented for ARMv8 for now.
3472 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3473 is substracted from total RAM and won't be reported to OS.
3474 This memory can be used as secure memory. A variable
3475 gd->arch.secure_ram is used to track the location. In systems
3476 the RAM base is not zero, or RAM is divided into banks,
3477 this variable needs to be recalcuated to get the address.
3479 - CONFIG_SYS_MEM_TOP_HIDE:
3480 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3481 this specified memory area will get subtracted from the top
3482 (end) of RAM and won't get "touched" at all by U-Boot. By
3483 fixing up gd->ram_size the Linux kernel should gets passed
3484 the now "corrected" memory size and won't touch it either.
3485 This should work for arch/ppc and arch/powerpc. Only Linux
3486 board ports in arch/powerpc with bootwrapper support that
3487 recalculate the memory size from the SDRAM controller setup
3488 will have to get fixed in Linux additionally.
3490 This option can be used as a workaround for the 440EPx/GRx
3491 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3494 WARNING: Please make sure that this value is a multiple of
3495 the Linux page size (normally 4k). If this is not the case,
3496 then the end address of the Linux memory will be located at a
3497 non page size aligned address and this could cause major
3500 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3501 Enable temporary baudrate change while serial download
3503 - CONFIG_SYS_SDRAM_BASE:
3504 Physical start address of SDRAM. _Must_ be 0 here.
3506 - CONFIG_SYS_FLASH_BASE:
3507 Physical start address of Flash memory.
3509 - CONFIG_SYS_MONITOR_BASE:
3510 Physical start address of boot monitor code (set by
3511 make config files to be same as the text base address
3512 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3513 CONFIG_SYS_FLASH_BASE when booting from flash.
3515 - CONFIG_SYS_MONITOR_LEN:
3516 Size of memory reserved for monitor code, used to
3517 determine _at_compile_time_ (!) if the environment is
3518 embedded within the U-Boot image, or in a separate
3521 - CONFIG_SYS_MALLOC_LEN:
3522 Size of DRAM reserved for malloc() use.
3524 - CONFIG_SYS_MALLOC_F_LEN
3525 Size of the malloc() pool for use before relocation. If
3526 this is defined, then a very simple malloc() implementation
3527 will become available before relocation. The address is just
3528 below the global data, and the stack is moved down to make
3531 This feature allocates regions with increasing addresses
3532 within the region. calloc() is supported, but realloc()
3533 is not available. free() is supported but does nothing.
3534 The memory will be freed (or in fact just forgotten) when
3535 U-Boot relocates itself.
3537 - CONFIG_SYS_MALLOC_SIMPLE
3538 Provides a simple and small malloc() and calloc() for those
3539 boards which do not use the full malloc in SPL (which is
3540 enabled with CONFIG_SYS_SPL_MALLOC_START).
3542 - CONFIG_SYS_NONCACHED_MEMORY:
3543 Size of non-cached memory area. This area of memory will be
3544 typically located right below the malloc() area and mapped
3545 uncached in the MMU. This is useful for drivers that would
3546 otherwise require a lot of explicit cache maintenance. For
3547 some drivers it's also impossible to properly maintain the
3548 cache. For example if the regions that need to be flushed
3549 are not a multiple of the cache-line size, *and* padding
3550 cannot be allocated between the regions to align them (i.e.
3551 if the HW requires a contiguous array of regions, and the
3552 size of each region is not cache-aligned), then a flush of
3553 one region may result in overwriting data that hardware has
3554 written to another region in the same cache-line. This can
3555 happen for example in network drivers where descriptors for
3556 buffers are typically smaller than the CPU cache-line (e.g.
3557 16 bytes vs. 32 or 64 bytes).
3559 Non-cached memory is only supported on 32-bit ARM at present.
3561 - CONFIG_SYS_BOOTM_LEN:
3562 Normally compressed uImages are limited to an
3563 uncompressed size of 8 MBytes. If this is not enough,
3564 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3565 to adjust this setting to your needs.
3567 - CONFIG_SYS_BOOTMAPSZ:
3568 Maximum size of memory mapped by the startup code of
3569 the Linux kernel; all data that must be processed by
3570 the Linux kernel (bd_info, boot arguments, FDT blob if
3571 used) must be put below this limit, unless "bootm_low"
3572 environment variable is defined and non-zero. In such case
3573 all data for the Linux kernel must be between "bootm_low"
3574 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3575 variable "bootm_mapsize" will override the value of
3576 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3577 then the value in "bootm_size" will be used instead.
3579 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3580 Enable initrd_high functionality. If defined then the
3581 initrd_high feature is enabled and the bootm ramdisk subcommand
3584 - CONFIG_SYS_BOOT_GET_CMDLINE:
3585 Enables allocating and saving kernel cmdline in space between
3586 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3588 - CONFIG_SYS_BOOT_GET_KBD:
3589 Enables allocating and saving a kernel copy of the bd_info in
3590 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3592 - CONFIG_SYS_MAX_FLASH_BANKS:
3593 Max number of Flash memory banks
3595 - CONFIG_SYS_MAX_FLASH_SECT:
3596 Max number of sectors on a Flash chip
3598 - CONFIG_SYS_FLASH_ERASE_TOUT:
3599 Timeout for Flash erase operations (in ms)
3601 - CONFIG_SYS_FLASH_WRITE_TOUT:
3602 Timeout for Flash write operations (in ms)
3604 - CONFIG_SYS_FLASH_LOCK_TOUT
3605 Timeout for Flash set sector lock bit operation (in ms)
3607 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3608 Timeout for Flash clear lock bits operation (in ms)
3610 - CONFIG_SYS_FLASH_PROTECTION
3611 If defined, hardware flash sectors protection is used
3612 instead of U-Boot software protection.
3614 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3616 Enable TFTP transfers directly to flash memory;
3617 without this option such a download has to be
3618 performed in two steps: (1) download to RAM, and (2)
3619 copy from RAM to flash.
3621 The two-step approach is usually more reliable, since
3622 you can check if the download worked before you erase
3623 the flash, but in some situations (when system RAM is
3624 too limited to allow for a temporary copy of the
3625 downloaded image) this option may be very useful.
3627 - CONFIG_SYS_FLASH_CFI:
3628 Define if the flash driver uses extra elements in the
3629 common flash structure for storing flash geometry.
3631 - CONFIG_FLASH_CFI_DRIVER
3632 This option also enables the building of the cfi_flash driver
3633 in the drivers directory
3635 - CONFIG_FLASH_CFI_MTD
3636 This option enables the building of the cfi_mtd driver
3637 in the drivers directory. The driver exports CFI flash
3640 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3641 Use buffered writes to flash.
3643 - CONFIG_FLASH_SPANSION_S29WS_N
3644 s29ws-n MirrorBit flash has non-standard addresses for buffered
3647 - CONFIG_SYS_FLASH_QUIET_TEST
3648 If this option is defined, the common CFI flash doesn't
3649 print it's warning upon not recognized FLASH banks. This
3650 is useful, if some of the configured banks are only
3651 optionally available.
3653 - CONFIG_FLASH_SHOW_PROGRESS
3654 If defined (must be an integer), print out countdown
3655 digits and dots. Recommended value: 45 (9..1) for 80
3656 column displays, 15 (3..1) for 40 column displays.
3658 - CONFIG_FLASH_VERIFY
3659 If defined, the content of the flash (destination) is compared
3660 against the source after the write operation. An error message
3661 will be printed when the contents are not identical.
3662 Please note that this option is useless in nearly all cases,
3663 since such flash programming errors usually are detected earlier
3664 while unprotecting/erasing/programming. Please only enable
3665 this option if you really know what you are doing.
3667 - CONFIG_SYS_RX_ETH_BUFFER:
3668 Defines the number of Ethernet receive buffers. On some
3669 Ethernet controllers it is recommended to set this value
3670 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3671 buffers can be full shortly after enabling the interface
3672 on high Ethernet traffic.
3673 Defaults to 4 if not defined.
3675 - CONFIG_ENV_MAX_ENTRIES
3677 Maximum number of entries in the hash table that is used
3678 internally to store the environment settings. The default
3679 setting is supposed to be generous and should work in most
3680 cases. This setting can be used to tune behaviour; see
3681 lib/hashtable.c for details.
3683 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3684 - CONFIG_ENV_FLAGS_LIST_STATIC
3685 Enable validation of the values given to environment variables when
3686 calling env set. Variables can be restricted to only decimal,
3687 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3688 the variables can also be restricted to IP address or MAC address.
3690 The format of the list is:
3691 type_attribute = [s|d|x|b|i|m]
3692 access_attribute = [a|r|o|c]
3693 attributes = type_attribute[access_attribute]
3694 entry = variable_name[:attributes]
3697 The type attributes are:
3698 s - String (default)
3701 b - Boolean ([1yYtT|0nNfF])
3705 The access attributes are:
3711 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3712 Define this to a list (string) to define the ".flags"
3713 environment variable in the default or embedded environment.
3715 - CONFIG_ENV_FLAGS_LIST_STATIC
3716 Define this to a list (string) to define validation that
3717 should be done if an entry is not found in the ".flags"
3718 environment variable. To override a setting in the static
3719 list, simply add an entry for the same variable name to the
3722 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3723 regular expression. This allows multiple variables to define the same
3724 flags without explicitly listing them for each variable.
3726 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3727 If defined, don't allow the -f switch to env set override variable
3730 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3731 This is set by OMAP boards for the max time that reset should
3732 be asserted. See doc/README.omap-reset-time for details on how
3733 the value can be calculated on a given board.
3736 If stdint.h is available with your toolchain you can define this
3737 option to enable it. You can provide option 'USE_STDINT=1' when
3738 building U-Boot to enable this.
3740 The following definitions that deal with the placement and management
3741 of environment data (variable area); in general, we support the
3742 following configurations:
3744 - CONFIG_BUILD_ENVCRC:
3746 Builds up envcrc with the target environment so that external utils
3747 may easily extract it and embed it in final U-Boot images.
3749 - CONFIG_ENV_IS_IN_FLASH:
3751 Define this if the environment is in flash memory.
3753 a) The environment occupies one whole flash sector, which is
3754 "embedded" in the text segment with the U-Boot code. This
3755 happens usually with "bottom boot sector" or "top boot
3756 sector" type flash chips, which have several smaller
3757 sectors at the start or the end. For instance, such a
3758 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3759 such a case you would place the environment in one of the
3760 4 kB sectors - with U-Boot code before and after it. With
3761 "top boot sector" type flash chips, you would put the
3762 environment in one of the last sectors, leaving a gap
3763 between U-Boot and the environment.
3765 - CONFIG_ENV_OFFSET:
3767 Offset of environment data (variable area) to the
3768 beginning of flash memory; for instance, with bottom boot
3769 type flash chips the second sector can be used: the offset
3770 for this sector is given here.
3772 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3776 This is just another way to specify the start address of
3777 the flash sector containing the environment (instead of
3780 - CONFIG_ENV_SECT_SIZE:
3782 Size of the sector containing the environment.
3785 b) Sometimes flash chips have few, equal sized, BIG sectors.
3786 In such a case you don't want to spend a whole sector for
3791 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3792 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3793 of this flash sector for the environment. This saves
3794 memory for the RAM copy of the environment.
3796 It may also save flash memory if you decide to use this
3797 when your environment is "embedded" within U-Boot code,
3798 since then the remainder of the flash sector could be used
3799 for U-Boot code. It should be pointed out that this is
3800 STRONGLY DISCOURAGED from a robustness point of view:
3801 updating the environment in flash makes it always
3802 necessary to erase the WHOLE sector. If something goes
3803 wrong before the contents has been restored from a copy in
3804 RAM, your target system will be dead.
3806 - CONFIG_ENV_ADDR_REDUND
3807 CONFIG_ENV_SIZE_REDUND
3809 These settings describe a second storage area used to hold
3810 a redundant copy of the environment data, so that there is
3811 a valid backup copy in case there is a power failure during
3812 a "saveenv" operation.
3814 BE CAREFUL! Any changes to the flash layout, and some changes to the
3815 source code will make it necessary to adapt <board>/u-boot.lds*
3819 - CONFIG_ENV_IS_IN_NVRAM:
3821 Define this if you have some non-volatile memory device
3822 (NVRAM, battery buffered SRAM) which you want to use for the
3828 These two #defines are used to determine the memory area you
3829 want to use for environment. It is assumed that this memory
3830 can just be read and written to, without any special
3833 BE CAREFUL! The first access to the environment happens quite early
3834 in U-Boot initialization (when we try to get the setting of for the
3835 console baudrate). You *MUST* have mapped your NVRAM area then, or
3838 Please note that even with NVRAM we still use a copy of the
3839 environment in RAM: we could work on NVRAM directly, but we want to
3840 keep settings there always unmodified except somebody uses "saveenv"
3841 to save the current settings.
3844 - CONFIG_ENV_IS_IN_EEPROM:
3846 Use this if you have an EEPROM or similar serial access
3847 device and a driver for it.
3849 - CONFIG_ENV_OFFSET:
3852 These two #defines specify the offset and size of the
3853 environment area within the total memory of your EEPROM.
3855 - CONFIG_SYS_I2C_EEPROM_ADDR:
3856 If defined, specified the chip address of the EEPROM device.
3857 The default address is zero.
3859 - CONFIG_SYS_I2C_EEPROM_BUS:
3860 If defined, specified the i2c bus of the EEPROM device.
3862 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3863 If defined, the number of bits used to address bytes in a
3864 single page in the EEPROM device. A 64 byte page, for example
3865 would require six bits.
3867 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3868 If defined, the number of milliseconds to delay between
3869 page writes. The default is zero milliseconds.
3871 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3872 The length in bytes of the EEPROM memory array address. Note
3873 that this is NOT the chip address length!
3875 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3876 EEPROM chips that implement "address overflow" are ones
3877 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3878 address and the extra bits end up in the "chip address" bit
3879 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3882 Note that we consider the length of the address field to
3883 still be one byte because the extra address bits are hidden
3884 in the chip address.
3886 - CONFIG_SYS_EEPROM_SIZE:
3887 The size in bytes of the EEPROM device.
3889 - CONFIG_ENV_EEPROM_IS_ON_I2C
3890 define this, if you have I2C and SPI activated, and your
3891 EEPROM, which holds the environment, is on the I2C bus.
3893 - CONFIG_I2C_ENV_EEPROM_BUS
3894 if you have an Environment on an EEPROM reached over
3895 I2C muxes, you can define here, how to reach this
3896 EEPROM. For example:
3898 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3900 EEPROM which holds the environment, is reached over
3901 a pca9547 i2c mux with address 0x70, channel 3.
3903 - CONFIG_ENV_IS_IN_DATAFLASH:
3905 Define this if you have a DataFlash memory device which you
3906 want to use for the environment.
3908 - CONFIG_ENV_OFFSET:
3912 These three #defines specify the offset and size of the
3913 environment area within the total memory of your DataFlash placed
3914 at the specified address.
3916 - CONFIG_ENV_IS_IN_SPI_FLASH:
3918 Define this if you have a SPI Flash memory device which you
3919 want to use for the environment.
3921 - CONFIG_ENV_OFFSET:
3924 These two #defines specify the offset and size of the
3925 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3926 aligned to an erase sector boundary.
3928 - CONFIG_ENV_SECT_SIZE:
3930 Define the SPI flash's sector size.
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 sector boundary.
3940 - CONFIG_ENV_SPI_BUS (optional):
3941 - CONFIG_ENV_SPI_CS (optional):
3943 Define the SPI bus and chip select. If not defined they will be 0.
3945 - CONFIG_ENV_SPI_MAX_HZ (optional):
3947 Define the SPI max work clock. If not defined then use 1MHz.
3949 - CONFIG_ENV_SPI_MODE (optional):
3951 Define the SPI work mode. If not defined then use SPI_MODE_3.
3953 - CONFIG_ENV_IS_IN_REMOTE:
3955 Define this if you have a remote memory space which you
3956 want to use for the local device's environment.
3961 These two #defines specify the address and size of the
3962 environment area within the remote memory space. The
3963 local device can get the environment from remote memory
3964 space by SRIO or PCIE links.
3966 BE CAREFUL! For some special cases, the local device can not use
3967 "saveenv" command. For example, the local device will get the
3968 environment stored in a remote NOR flash by SRIO or PCIE link,
3969 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3971 - CONFIG_ENV_IS_IN_NAND:
3973 Define this if you have a NAND device which you want to use
3974 for the environment.
3976 - CONFIG_ENV_OFFSET:
3979 These two #defines specify the offset and size of the environment
3980 area within the first NAND device. CONFIG_ENV_OFFSET must be
3981 aligned to an erase block boundary.
3983 - CONFIG_ENV_OFFSET_REDUND (optional):
3985 This setting describes a second storage area of CONFIG_ENV_SIZE
3986 size used to hold a redundant copy of the environment data, so
3987 that there is a valid backup copy in case there is a power failure
3988 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3989 aligned to an erase block boundary.
3991 - CONFIG_ENV_RANGE (optional):
3993 Specifies the length of the region in which the environment
3994 can be written. This should be a multiple of the NAND device's
3995 block size. Specifying a range with more erase blocks than
3996 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3997 the range to be avoided.
3999 - CONFIG_ENV_OFFSET_OOB (optional):
4001 Enables support for dynamically retrieving the offset of the
4002 environment from block zero's out-of-band data. The
4003 "nand env.oob" command can be used to record this offset.
4004 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4005 using CONFIG_ENV_OFFSET_OOB.
4007 - CONFIG_NAND_ENV_DST
4009 Defines address in RAM to which the nand_spl code should copy the
4010 environment. If redundant environment is used, it will be copied to
4011 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4013 - CONFIG_ENV_IS_IN_UBI:
4015 Define this if you have an UBI volume that you want to use for the
4016 environment. This has the benefit of wear-leveling the environment
4017 accesses, which is important on NAND.
4019 - CONFIG_ENV_UBI_PART:
4021 Define this to a string that is the mtd partition containing the UBI.
4023 - CONFIG_ENV_UBI_VOLUME:
4025 Define this to the name of the volume that you want to store the
4028 - CONFIG_ENV_UBI_VOLUME_REDUND:
4030 Define this to the name of another volume to store a second copy of
4031 the environment in. This will enable redundant environments in UBI.
4032 It is assumed that both volumes are in the same MTD partition.
4034 - CONFIG_UBI_SILENCE_MSG
4035 - CONFIG_UBIFS_SILENCE_MSG
4037 You will probably want to define these to avoid a really noisy system
4038 when storing the env in UBI.
4040 - CONFIG_ENV_IS_IN_FAT:
4041 Define this if you want to use the FAT file system for the environment.
4043 - FAT_ENV_INTERFACE:
4045 Define this to a string that is the name of the block device.
4047 - FAT_ENV_DEVICE_AND_PART:
4049 Define this to a string to specify the partition of the device. It can
4052 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4053 - "D:P": device D partition P. Error occurs if device D has no
4056 - "D" or "D:": device D partition 1 if device D has partition
4057 table, or the whole device D if has no partition
4059 - "D:auto": first partition in device D with bootable flag set.
4060 If none, first valid partition in device D. If no
4061 partition table then means device D.
4065 It's a string of the FAT file name. This file use to store the
4069 This should be defined. Otherwise it cannot save the environment file.
4071 - CONFIG_ENV_IS_IN_MMC:
4073 Define this if you have an MMC device which you want to use for the
4076 - CONFIG_SYS_MMC_ENV_DEV:
4078 Specifies which MMC device the environment is stored in.
4080 - CONFIG_SYS_MMC_ENV_PART (optional):
4082 Specifies which MMC partition the environment is stored in. If not
4083 set, defaults to partition 0, the user area. Common values might be
4084 1 (first MMC boot partition), 2 (second MMC boot partition).
4086 - CONFIG_ENV_OFFSET:
4089 These two #defines specify the offset and size of the environment
4090 area within the specified MMC device.
4092 If offset is positive (the usual case), it is treated as relative to
4093 the start of the MMC partition. If offset is negative, it is treated
4094 as relative to the end of the MMC partition. This can be useful if
4095 your board may be fitted with different MMC devices, which have
4096 different sizes for the MMC partitions, and you always want the
4097 environment placed at the very end of the partition, to leave the
4098 maximum possible space before it, to store other data.
4100 These two values are in units of bytes, but must be aligned to an
4101 MMC sector boundary.
4103 - CONFIG_ENV_OFFSET_REDUND (optional):
4105 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4106 hold a redundant copy of the environment data. This provides a
4107 valid backup copy in case the other copy is corrupted, e.g. due
4108 to a power failure during a "saveenv" operation.
4110 This value may also be positive or negative; this is handled in the
4111 same way as CONFIG_ENV_OFFSET.
4113 This value is also in units of bytes, but must also be aligned to
4114 an MMC sector boundary.
4116 - CONFIG_ENV_SIZE_REDUND (optional):
4118 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4119 set. If this value is set, it must be set to the same value as
4122 - CONFIG_SYS_SPI_INIT_OFFSET
4124 Defines offset to the initial SPI buffer area in DPRAM. The
4125 area is used at an early stage (ROM part) if the environment
4126 is configured to reside in the SPI EEPROM: We need a 520 byte
4127 scratch DPRAM area. It is used between the two initialization
4128 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4129 to be a good choice since it makes it far enough from the
4130 start of the data area as well as from the stack pointer.
4132 Please note that the environment is read-only until the monitor
4133 has been relocated to RAM and a RAM copy of the environment has been
4134 created; also, when using EEPROM you will have to use getenv_f()
4135 until then to read environment variables.
4137 The environment is protected by a CRC32 checksum. Before the monitor
4138 is relocated into RAM, as a result of a bad CRC you will be working
4139 with the compiled-in default environment - *silently*!!! [This is
4140 necessary, because the first environment variable we need is the
4141 "baudrate" setting for the console - if we have a bad CRC, we don't
4142 have any device yet where we could complain.]
4144 Note: once the monitor has been relocated, then it will complain if
4145 the default environment is used; a new CRC is computed as soon as you
4146 use the "saveenv" command to store a valid environment.
4148 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4149 Echo the inverted Ethernet link state to the fault LED.
4151 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4152 also needs to be defined.
4154 - CONFIG_SYS_FAULT_MII_ADDR:
4155 MII address of the PHY to check for the Ethernet link state.
4157 - CONFIG_NS16550_MIN_FUNCTIONS:
4158 Define this if you desire to only have use of the NS16550_init
4159 and NS16550_putc functions for the serial driver located at
4160 drivers/serial/ns16550.c. This option is useful for saving
4161 space for already greatly restricted images, including but not
4162 limited to NAND_SPL configurations.
4164 - CONFIG_DISPLAY_BOARDINFO
4165 Display information about the board that U-Boot is running on
4166 when U-Boot starts up. The board function checkboard() is called
4169 - CONFIG_DISPLAY_BOARDINFO_LATE
4170 Similar to the previous option, but display this information
4171 later, once stdio is running and output goes to the LCD, if
4174 - CONFIG_BOARD_SIZE_LIMIT:
4175 Maximum size of the U-Boot image. When defined, the
4176 build system checks that the actual size does not
4179 Low Level (hardware related) configuration options:
4180 ---------------------------------------------------
4182 - CONFIG_SYS_CACHELINE_SIZE:
4183 Cache Line Size of the CPU.
4185 - CONFIG_SYS_DEFAULT_IMMR:
4186 Default address of the IMMR after system reset.
4188 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4189 and RPXsuper) to be able to adjust the position of
4190 the IMMR register after a reset.
4192 - CONFIG_SYS_CCSRBAR_DEFAULT:
4193 Default (power-on reset) physical address of CCSR on Freescale
4196 - CONFIG_SYS_CCSRBAR:
4197 Virtual address of CCSR. On a 32-bit build, this is typically
4198 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4200 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4201 for cross-platform code that uses that macro instead.
4203 - CONFIG_SYS_CCSRBAR_PHYS:
4204 Physical address of CCSR. CCSR can be relocated to a new
4205 physical address, if desired. In this case, this macro should
4206 be set to that address. Otherwise, it should be set to the
4207 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4208 is typically relocated on 36-bit builds. It is recommended
4209 that this macro be defined via the _HIGH and _LOW macros:
4211 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4212 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4214 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4215 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4216 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4217 used in assembly code, so it must not contain typecasts or
4218 integer size suffixes (e.g. "ULL").
4220 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4221 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4222 used in assembly code, so it must not contain typecasts or
4223 integer size suffixes (e.g. "ULL").
4225 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4226 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4227 forced to a value that ensures that CCSR is not relocated.
4229 - Floppy Disk Support:
4230 CONFIG_SYS_FDC_DRIVE_NUMBER
4232 the default drive number (default value 0)
4234 CONFIG_SYS_ISA_IO_STRIDE
4236 defines the spacing between FDC chipset registers
4239 CONFIG_SYS_ISA_IO_OFFSET
4241 defines the offset of register from address. It
4242 depends on which part of the data bus is connected to
4243 the FDC chipset. (default value 0)
4245 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4246 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4249 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4250 fdc_hw_init() is called at the beginning of the FDC
4251 setup. fdc_hw_init() must be provided by the board
4252 source code. It is used to make hardware-dependent
4256 Most IDE controllers were designed to be connected with PCI
4257 interface. Only few of them were designed for AHB interface.
4258 When software is doing ATA command and data transfer to
4259 IDE devices through IDE-AHB controller, some additional
4260 registers accessing to these kind of IDE-AHB controller
4263 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4264 DO NOT CHANGE unless you know exactly what you're
4265 doing! (11-4) [MPC8xx/82xx systems only]
4267 - CONFIG_SYS_INIT_RAM_ADDR:
4269 Start address of memory area that can be used for
4270 initial data and stack; please note that this must be
4271 writable memory that is working WITHOUT special
4272 initialization, i. e. you CANNOT use normal RAM which
4273 will become available only after programming the
4274 memory controller and running certain initialization
4277 U-Boot uses the following memory types:
4278 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4279 - MPC824X: data cache
4280 - PPC4xx: data cache
4282 - CONFIG_SYS_GBL_DATA_OFFSET:
4284 Offset of the initial data structure in the memory
4285 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4286 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4287 data is located at the end of the available space
4288 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4289 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4290 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4291 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4294 On the MPC824X (or other systems that use the data
4295 cache for initial memory) the address chosen for
4296 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4297 point to an otherwise UNUSED address space between
4298 the top of RAM and the start of the PCI space.
4300 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4302 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4304 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4306 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4308 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4310 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4312 - CONFIG_SYS_OR_TIMING_SDRAM:
4315 - CONFIG_SYS_MAMR_PTA:
4316 periodic timer for refresh
4318 - CONFIG_SYS_DER: Debug Event Register (37-47)
4320 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4321 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4322 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4323 CONFIG_SYS_BR1_PRELIM:
4324 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4326 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4327 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4328 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4329 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4331 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4332 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4333 Machine Mode Register and Memory Periodic Timer
4334 Prescaler definitions (SDRAM timing)
4336 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4337 enable I2C microcode relocation patch (MPC8xx);
4338 define relocation offset in DPRAM [DSP2]
4340 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4341 enable SMC microcode relocation patch (MPC8xx);
4342 define relocation offset in DPRAM [SMC1]
4344 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4345 enable SPI microcode relocation patch (MPC8xx);
4346 define relocation offset in DPRAM [SCC4]
4348 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4349 Offset of the bootmode word in DPRAM used by post
4350 (Power On Self Tests). This definition overrides
4351 #define'd default value in commproc.h resp.
4354 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4355 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4356 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4357 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4358 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4359 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4360 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4361 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4362 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4364 - CONFIG_PCI_DISABLE_PCIE:
4365 Disable PCI-Express on systems where it is supported but not
4368 - CONFIG_PCI_ENUM_ONLY
4369 Only scan through and get the devices on the buses.
4370 Don't do any setup work, presumably because someone or
4371 something has already done it, and we don't need to do it
4372 a second time. Useful for platforms that are pre-booted
4373 by coreboot or similar.
4375 - CONFIG_PCI_INDIRECT_BRIDGE:
4376 Enable support for indirect PCI bridges.
4379 Chip has SRIO or not
4382 Board has SRIO 1 port available
4385 Board has SRIO 2 port available
4387 - CONFIG_SRIO_PCIE_BOOT_MASTER
4388 Board can support master function for Boot from SRIO and PCIE
4390 - CONFIG_SYS_SRIOn_MEM_VIRT:
4391 Virtual Address of SRIO port 'n' memory region
4393 - CONFIG_SYS_SRIOn_MEM_PHYS:
4394 Physical Address of SRIO port 'n' memory region
4396 - CONFIG_SYS_SRIOn_MEM_SIZE:
4397 Size of SRIO port 'n' memory region
4399 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4400 Defined to tell the NAND controller that the NAND chip is using
4402 Not all NAND drivers use this symbol.
4403 Example of drivers that use it:
4404 - drivers/mtd/nand/ndfc.c
4405 - drivers/mtd/nand/mxc_nand.c
4407 - CONFIG_SYS_NDFC_EBC0_CFG
4408 Sets the EBC0_CFG register for the NDFC. If not defined
4409 a default value will be used.
4412 Get DDR timing information from an I2C EEPROM. Common
4413 with pluggable memory modules such as SODIMMs
4416 I2C address of the SPD EEPROM
4418 - CONFIG_SYS_SPD_BUS_NUM
4419 If SPD EEPROM is on an I2C bus other than the first
4420 one, specify here. Note that the value must resolve
4421 to something your driver can deal with.
4423 - CONFIG_SYS_DDR_RAW_TIMING
4424 Get DDR timing information from other than SPD. Common with
4425 soldered DDR chips onboard without SPD. DDR raw timing
4426 parameters are extracted from datasheet and hard-coded into
4427 header files or board specific files.
4429 - CONFIG_FSL_DDR_INTERACTIVE
4430 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4432 - CONFIG_FSL_DDR_SYNC_REFRESH
4433 Enable sync of refresh for multiple controllers.
4435 - CONFIG_FSL_DDR_BIST
4436 Enable built-in memory test for Freescale DDR controllers.
4438 - CONFIG_SYS_83XX_DDR_USES_CS0
4439 Only for 83xx systems. If specified, then DDR should
4440 be configured using CS0 and CS1 instead of CS2 and CS3.
4442 - CONFIG_ETHER_ON_FEC[12]
4443 Define to enable FEC[12] on a 8xx series processor.
4445 - CONFIG_FEC[12]_PHY
4446 Define to the hardcoded PHY address which corresponds
4447 to the given FEC; i. e.
4448 #define CONFIG_FEC1_PHY 4
4449 means that the PHY with address 4 is connected to FEC1
4451 When set to -1, means to probe for first available.
4453 - CONFIG_FEC[12]_PHY_NORXERR
4454 The PHY does not have a RXERR line (RMII only).
4455 (so program the FEC to ignore it).
4458 Enable RMII mode for all FECs.
4459 Note that this is a global option, we can't
4460 have one FEC in standard MII mode and another in RMII mode.
4462 - CONFIG_CRC32_VERIFY
4463 Add a verify option to the crc32 command.
4466 => crc32 -v <address> <count> <crc32>
4468 Where address/count indicate a memory area
4469 and crc32 is the correct crc32 which the
4473 Add the "loopw" memory command. This only takes effect if
4474 the memory commands are activated globally (CONFIG_CMD_MEM).
4477 Add the "mdc" and "mwc" memory commands. These are cyclic
4482 This command will print 4 bytes (10,11,12,13) each 500 ms.
4484 => mwc.l 100 12345678 10
4485 This command will write 12345678 to address 100 all 10 ms.
4487 This only takes effect if the memory commands are activated
4488 globally (CONFIG_CMD_MEM).
4490 - CONFIG_SKIP_LOWLEVEL_INIT
4491 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4492 low level initializations (like setting up the memory
4493 controller) are omitted and/or U-Boot does not
4494 relocate itself into RAM.
4496 Normally this variable MUST NOT be defined. The only
4497 exception is when U-Boot is loaded (to RAM) by some
4498 other boot loader or by a debugger which performs
4499 these initializations itself.
4501 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4502 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4503 to be skipped. The normal CP15 init (such as enabling the
4504 instruction cache) is still performed.
4507 Modifies the behaviour of start.S when compiling a loader
4508 that is executed before the actual U-Boot. E.g. when
4509 compiling a NAND SPL.
4512 Modifies the behaviour of start.S when compiling a loader
4513 that is executed after the SPL and before the actual U-Boot.
4514 It is loaded by the SPL.
4516 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4517 Only for 85xx systems. If this variable is specified, the section
4518 .resetvec is not kept and the section .bootpg is placed in the
4519 previous 4k of the .text section.
4521 - CONFIG_ARCH_MAP_SYSMEM
4522 Generally U-Boot (and in particular the md command) uses
4523 effective address. It is therefore not necessary to regard
4524 U-Boot address as virtual addresses that need to be translated
4525 to physical addresses. However, sandbox requires this, since
4526 it maintains its own little RAM buffer which contains all
4527 addressable memory. This option causes some memory accesses
4528 to be mapped through map_sysmem() / unmap_sysmem().
4530 - CONFIG_X86_RESET_VECTOR
4531 If defined, the x86 reset vector code is included. This is not
4532 needed when U-Boot is running from Coreboot.
4535 Defines the MPU clock speed (in MHz).
4537 NOTE : currently only supported on AM335x platforms.
4539 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4540 Enables the RTC32K OSC on AM33xx based plattforms
4542 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4543 Option to disable subpage write in NAND driver
4544 driver that uses this:
4545 drivers/mtd/nand/davinci_nand.c
4547 Freescale QE/FMAN Firmware Support:
4548 -----------------------------------
4550 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4551 loading of "firmware", which is encoded in the QE firmware binary format.
4552 This firmware often needs to be loaded during U-Boot booting, so macros
4553 are used to identify the storage device (NOR flash, SPI, etc) and the address
4556 - CONFIG_SYS_FMAN_FW_ADDR
4557 The address in the storage device where the FMAN microcode is located. The
4558 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4561 - CONFIG_SYS_QE_FW_ADDR
4562 The address in the storage device where the QE microcode is located. The
4563 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4566 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4567 The maximum possible size of the firmware. The firmware binary format
4568 has a field that specifies the actual size of the firmware, but it
4569 might not be possible to read any part of the firmware unless some
4570 local storage is allocated to hold the entire firmware first.
4572 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4573 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4574 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4575 virtual address in NOR flash.
4577 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4578 Specifies that QE/FMAN firmware is located in NAND flash.
4579 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4581 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4582 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4583 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4585 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4586 Specifies that QE/FMAN firmware is located in the remote (master)
4587 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4588 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4589 window->master inbound window->master LAW->the ucode address in
4590 master's memory space.
4592 Freescale Layerscape Management Complex Firmware Support:
4593 ---------------------------------------------------------
4594 The Freescale Layerscape Management Complex (MC) supports the loading of
4596 This firmware often needs to be loaded during U-Boot booting, so macros
4597 are used to identify the storage device (NOR flash, SPI, etc) and the address
4600 - CONFIG_FSL_MC_ENET
4601 Enable the MC driver for Layerscape SoCs.
4603 Freescale Layerscape Debug Server Support:
4604 -------------------------------------------
4605 The Freescale Layerscape Debug Server Support supports the loading of
4606 "Debug Server firmware" and triggering SP boot-rom.
4607 This firmware often needs to be loaded during U-Boot booting.
4609 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4610 Define alignment of reserved memory MC requires
4615 In order to achieve reproducible builds, timestamps used in the U-Boot build
4616 process have to be set to a fixed value.
4618 This is done using the SOURCE_DATE_EPOCH environment variable.
4619 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4620 option for U-Boot or an environment variable in U-Boot.
4622 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4624 Building the Software:
4625 ======================
4627 Building U-Boot has been tested in several native build environments
4628 and in many different cross environments. Of course we cannot support
4629 all possibly existing versions of cross development tools in all
4630 (potentially obsolete) versions. In case of tool chain problems we
4631 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4632 which is extensively used to build and test U-Boot.
4634 If you are not using a native environment, it is assumed that you
4635 have GNU cross compiling tools available in your path. In this case,
4636 you must set the environment variable CROSS_COMPILE in your shell.
4637 Note that no changes to the Makefile or any other source files are
4638 necessary. For example using the ELDK on a 4xx CPU, please enter:
4640 $ CROSS_COMPILE=ppc_4xx-
4641 $ export CROSS_COMPILE
4643 Note: If you wish to generate Windows versions of the utilities in
4644 the tools directory you can use the MinGW toolchain
4645 (http://www.mingw.org). Set your HOST tools to the MinGW
4646 toolchain and execute 'make tools'. For example:
4648 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4650 Binaries such as tools/mkimage.exe will be created which can
4651 be executed on computers running Windows.
4653 U-Boot is intended to be simple to build. After installing the
4654 sources you must configure U-Boot for one specific board type. This
4659 where "NAME_defconfig" is the name of one of the existing configu-
4660 rations; see boards.cfg for supported names.
4662 Note: for some board special configuration names may exist; check if
4663 additional information is available from the board vendor; for
4664 instance, the TQM823L systems are available without (standard)
4665 or with LCD support. You can select such additional "features"
4666 when choosing the configuration, i. e.
4668 make TQM823L_defconfig
4669 - will configure for a plain TQM823L, i. e. no LCD support
4671 make TQM823L_LCD_defconfig
4672 - will configure for a TQM823L with U-Boot console on LCD
4677 Finally, type "make all", and you should get some working U-Boot
4678 images ready for download to / installation on your system:
4680 - "u-boot.bin" is a raw binary image
4681 - "u-boot" is an image in ELF binary format
4682 - "u-boot.srec" is in Motorola S-Record format
4684 By default the build is performed locally and the objects are saved
4685 in the source directory. One of the two methods can be used to change
4686 this behavior and build U-Boot to some external directory:
4688 1. Add O= to the make command line invocations:
4690 make O=/tmp/build distclean
4691 make O=/tmp/build NAME_defconfig
4692 make O=/tmp/build all
4694 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4696 export KBUILD_OUTPUT=/tmp/build
4701 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4705 Please be aware that the Makefiles assume you are using GNU make, so
4706 for instance on NetBSD you might need to use "gmake" instead of
4710 If the system board that you have is not listed, then you will need
4711 to port U-Boot to your hardware platform. To do this, follow these
4714 1. Create a new directory to hold your board specific code. Add any
4715 files you need. In your board directory, you will need at least
4716 the "Makefile" and a "<board>.c".
4717 2. Create a new configuration file "include/configs/<board>.h" for
4719 3. If you're porting U-Boot to a new CPU, then also create a new
4720 directory to hold your CPU specific code. Add any files you need.
4721 4. Run "make <board>_defconfig" with your new name.
4722 5. Type "make", and you should get a working "u-boot.srec" file
4723 to be installed on your target system.
4724 6. Debug and solve any problems that might arise.
4725 [Of course, this last step is much harder than it sounds.]
4728 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4729 ==============================================================
4731 If you have modified U-Boot sources (for instance added a new board
4732 or support for new devices, a new CPU, etc.) you are expected to
4733 provide feedback to the other developers. The feedback normally takes
4734 the form of a "patch", i. e. a context diff against a certain (latest
4735 official or latest in the git repository) version of U-Boot sources.
4737 But before you submit such a patch, please verify that your modifi-
4738 cation did not break existing code. At least make sure that *ALL* of
4739 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4740 just run the buildman script (tools/buildman/buildman), which will
4741 configure and build U-Boot for ALL supported system. Be warned, this
4742 will take a while. Please see the buildman README, or run 'buildman -H'
4746 See also "U-Boot Porting Guide" below.
4749 Monitor Commands - Overview:
4750 ============================
4752 go - start application at address 'addr'
4753 run - run commands in an environment variable
4754 bootm - boot application image from memory
4755 bootp - boot image via network using BootP/TFTP protocol
4756 bootz - boot zImage from memory
4757 tftpboot- boot image via network using TFTP protocol
4758 and env variables "ipaddr" and "serverip"
4759 (and eventually "gatewayip")
4760 tftpput - upload a file via network using TFTP protocol
4761 rarpboot- boot image via network using RARP/TFTP protocol
4762 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4763 loads - load S-Record file over serial line
4764 loadb - load binary file over serial line (kermit mode)
4766 mm - memory modify (auto-incrementing)
4767 nm - memory modify (constant address)
4768 mw - memory write (fill)
4770 cmp - memory compare
4771 crc32 - checksum calculation
4772 i2c - I2C sub-system
4773 sspi - SPI utility commands
4774 base - print or set address offset
4775 printenv- print environment variables
4776 setenv - set environment variables
4777 saveenv - save environment variables to persistent storage
4778 protect - enable or disable FLASH write protection
4779 erase - erase FLASH memory
4780 flinfo - print FLASH memory information
4781 nand - NAND memory operations (see doc/README.nand)
4782 bdinfo - print Board Info structure
4783 iminfo - print header information for application image
4784 coninfo - print console devices and informations
4785 ide - IDE sub-system
4786 loop - infinite loop on address range
4787 loopw - infinite write loop on address range
4788 mtest - simple RAM test
4789 icache - enable or disable instruction cache
4790 dcache - enable or disable data cache
4791 reset - Perform RESET of the CPU
4792 echo - echo args to console
4793 version - print monitor version
4794 help - print online help
4795 ? - alias for 'help'
4798 Monitor Commands - Detailed Description:
4799 ========================================
4803 For now: just type "help <command>".
4806 Environment Variables:
4807 ======================
4809 U-Boot supports user configuration using Environment Variables which
4810 can be made persistent by saving to Flash memory.
4812 Environment Variables are set using "setenv", printed using
4813 "printenv", and saved to Flash using "saveenv". Using "setenv"
4814 without a value can be used to delete a variable from the
4815 environment. As long as you don't save the environment you are
4816 working with an in-memory copy. In case the Flash area containing the
4817 environment is erased by accident, a default environment is provided.
4819 Some configuration options can be set using Environment Variables.
4821 List of environment variables (most likely not complete):
4823 baudrate - see CONFIG_BAUDRATE
4825 bootdelay - see CONFIG_BOOTDELAY
4827 bootcmd - see CONFIG_BOOTCOMMAND
4829 bootargs - Boot arguments when booting an RTOS image
4831 bootfile - Name of the image to load with TFTP
4833 bootm_low - Memory range available for image processing in the bootm
4834 command can be restricted. This variable is given as
4835 a hexadecimal number and defines lowest address allowed
4836 for use by the bootm command. See also "bootm_size"
4837 environment variable. Address defined by "bootm_low" is
4838 also the base of the initial memory mapping for the Linux
4839 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4842 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4843 This variable is given as a hexadecimal number and it
4844 defines the size of the memory region starting at base
4845 address bootm_low that is accessible by the Linux kernel
4846 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4847 as the default value if it is defined, and bootm_size is
4850 bootm_size - Memory range available for image processing in the bootm
4851 command can be restricted. This variable is given as
4852 a hexadecimal number and defines the size of the region
4853 allowed for use by the bootm command. See also "bootm_low"
4854 environment variable.
4856 updatefile - Location of the software update file on a TFTP server, used
4857 by the automatic software update feature. Please refer to
4858 documentation in doc/README.update for more details.
4860 autoload - if set to "no" (any string beginning with 'n'),
4861 "bootp" will just load perform a lookup of the
4862 configuration from the BOOTP server, but not try to
4863 load any image using TFTP
4865 autostart - if set to "yes", an image loaded using the "bootp",
4866 "rarpboot", "tftpboot" or "diskboot" commands will
4867 be automatically started (by internally calling
4870 If set to "no", a standalone image passed to the
4871 "bootm" command will be copied to the load address
4872 (and eventually uncompressed), but NOT be started.
4873 This can be used to load and uncompress arbitrary
4876 fdt_high - if set this restricts the maximum address that the
4877 flattened device tree will be copied into upon boot.
4878 For example, if you have a system with 1 GB memory
4879 at physical address 0x10000000, while Linux kernel
4880 only recognizes the first 704 MB as low memory, you
4881 may need to set fdt_high as 0x3C000000 to have the
4882 device tree blob be copied to the maximum address
4883 of the 704 MB low memory, so that Linux kernel can
4884 access it during the boot procedure.
4886 If this is set to the special value 0xFFFFFFFF then
4887 the fdt will not be copied at all on boot. For this
4888 to work it must reside in writable memory, have
4889 sufficient padding on the end of it for u-boot to
4890 add the information it needs into it, and the memory
4891 must be accessible by the kernel.
4893 fdtcontroladdr- if set this is the address of the control flattened
4894 device tree used by U-Boot when CONFIG_OF_CONTROL is
4897 i2cfast - (PPC405GP|PPC405EP only)
4898 if set to 'y' configures Linux I2C driver for fast
4899 mode (400kHZ). This environment variable is used in
4900 initialization code. So, for changes to be effective
4901 it must be saved and board must be reset.
4903 initrd_high - restrict positioning of initrd images:
4904 If this variable is not set, initrd images will be
4905 copied to the highest possible address in RAM; this
4906 is usually what you want since it allows for
4907 maximum initrd size. If for some reason you want to
4908 make sure that the initrd image is loaded below the
4909 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4910 variable to a value of "no" or "off" or "0".
4911 Alternatively, you can set it to a maximum upper
4912 address to use (U-Boot will still check that it
4913 does not overwrite the U-Boot stack and data).
4915 For instance, when you have a system with 16 MB
4916 RAM, and want to reserve 4 MB from use by Linux,
4917 you can do this by adding "mem=12M" to the value of
4918 the "bootargs" variable. However, now you must make
4919 sure that the initrd image is placed in the first
4920 12 MB as well - this can be done with
4922 setenv initrd_high 00c00000
4924 If you set initrd_high to 0xFFFFFFFF, this is an
4925 indication to U-Boot that all addresses are legal
4926 for the Linux kernel, including addresses in flash
4927 memory. In this case U-Boot will NOT COPY the
4928 ramdisk at all. This may be useful to reduce the
4929 boot time on your system, but requires that this
4930 feature is supported by your Linux kernel.
4932 ipaddr - IP address; needed for tftpboot command
4934 loadaddr - Default load address for commands like "bootp",
4935 "rarpboot", "tftpboot", "loadb" or "diskboot"
4937 loads_echo - see CONFIG_LOADS_ECHO
4939 serverip - TFTP server IP address; needed for tftpboot command
4941 bootretry - see CONFIG_BOOT_RETRY_TIME
4943 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4945 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4947 ethprime - controls which interface is used first.
4949 ethact - controls which interface is currently active.
4950 For example you can do the following
4952 => setenv ethact FEC
4953 => ping 192.168.0.1 # traffic sent on FEC
4954 => setenv ethact SCC
4955 => ping 10.0.0.1 # traffic sent on SCC
4957 ethrotate - When set to "no" U-Boot does not go through all
4958 available network interfaces.
4959 It just stays at the currently selected interface.
4961 netretry - When set to "no" each network operation will
4962 either succeed or fail without retrying.
4963 When set to "once" the network operation will
4964 fail when all the available network interfaces
4965 are tried once without success.
4966 Useful on scripts which control the retry operation
4969 npe_ucode - set load address for the NPE microcode
4971 silent_linux - If set then Linux will be told to boot silently, by
4972 changing the console to be empty. If "yes" it will be
4973 made silent. If "no" it will not be made silent. If
4974 unset, then it will be made silent if the U-Boot console
4977 tftpsrcp - If this is set, the value is used for TFTP's
4980 tftpdstp - If this is set, the value is used for TFTP's UDP
4981 destination port instead of the Well Know Port 69.
4983 tftpblocksize - Block size to use for TFTP transfers; if not set,
4984 we use the TFTP server's default block size
4986 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4987 seconds, minimum value is 1000 = 1 second). Defines
4988 when a packet is considered to be lost so it has to
4989 be retransmitted. The default is 5000 = 5 seconds.
4990 Lowering this value may make downloads succeed
4991 faster in networks with high packet loss rates or
4992 with unreliable TFTP servers.
4994 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4995 unit, minimum value = 0). Defines how many timeouts
4996 can happen during a single file transfer before that
4997 transfer is aborted. The default is 10, and 0 means
4998 'no timeouts allowed'. Increasing this value may help
4999 downloads succeed with high packet loss rates, or with
5000 unreliable TFTP servers or client hardware.
5002 vlan - When set to a value < 4095 the traffic over
5003 Ethernet is encapsulated/received over 802.1q
5006 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5007 Unsigned value, in milliseconds. If not set, the period will
5008 be either the default (28000), or a value based on
5009 CONFIG_NET_RETRY_COUNT, if defined. This value has
5010 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5012 The following image location variables contain the location of images
5013 used in booting. The "Image" column gives the role of the image and is
5014 not an environment variable name. The other columns are environment
5015 variable names. "File Name" gives the name of the file on a TFTP
5016 server, "RAM Address" gives the location in RAM the image will be
5017 loaded to, and "Flash Location" gives the image's address in NOR
5018 flash or offset in NAND flash.
5020 *Note* - these variables don't have to be defined for all boards, some
5021 boards currently use other variables for these purposes, and some
5022 boards use these variables for other purposes.
5024 Image File Name RAM Address Flash Location
5025 ----- --------- ----------- --------------
5026 u-boot u-boot u-boot_addr_r u-boot_addr
5027 Linux kernel bootfile kernel_addr_r kernel_addr
5028 device tree blob fdtfile fdt_addr_r fdt_addr
5029 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5031 The following environment variables may be used and automatically
5032 updated by the network boot commands ("bootp" and "rarpboot"),
5033 depending the information provided by your boot server:
5035 bootfile - see above
5036 dnsip - IP address of your Domain Name Server
5037 dnsip2 - IP address of your secondary Domain Name Server
5038 gatewayip - IP address of the Gateway (Router) to use
5039 hostname - Target hostname
5041 netmask - Subnet Mask
5042 rootpath - Pathname of the root filesystem on the NFS server
5043 serverip - see above
5046 There are two special Environment Variables:
5048 serial# - contains hardware identification information such
5049 as type string and/or serial number
5050 ethaddr - Ethernet address
5052 These variables can be set only once (usually during manufacturing of
5053 the board). U-Boot refuses to delete or overwrite these variables
5054 once they have been set once.
5057 Further special Environment Variables:
5059 ver - Contains the U-Boot version string as printed
5060 with the "version" command. This variable is
5061 readonly (see CONFIG_VERSION_VARIABLE).
5064 Please note that changes to some configuration parameters may take
5065 only effect after the next boot (yes, that's just like Windoze :-).
5068 Callback functions for environment variables:
5069 ---------------------------------------------
5071 For some environment variables, the behavior of u-boot needs to change
5072 when their values are changed. This functionality allows functions to
5073 be associated with arbitrary variables. On creation, overwrite, or
5074 deletion, the callback will provide the opportunity for some side
5075 effect to happen or for the change to be rejected.
5077 The callbacks are named and associated with a function using the
5078 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5080 These callbacks are associated with variables in one of two ways. The
5081 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5082 in the board configuration to a string that defines a list of
5083 associations. The list must be in the following format:
5085 entry = variable_name[:callback_name]
5088 If the callback name is not specified, then the callback is deleted.
5089 Spaces are also allowed anywhere in the list.
5091 Callbacks can also be associated by defining the ".callbacks" variable
5092 with the same list format above. Any association in ".callbacks" will
5093 override any association in the static list. You can define
5094 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5095 ".callbacks" environment variable in the default or embedded environment.
5097 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5098 regular expression. This allows multiple variables to be connected to
5099 the same callback without explicitly listing them all out.
5102 Command Line Parsing:
5103 =====================
5105 There are two different command line parsers available with U-Boot:
5106 the old "simple" one, and the much more powerful "hush" shell:
5108 Old, simple command line parser:
5109 --------------------------------
5111 - supports environment variables (through setenv / saveenv commands)
5112 - several commands on one line, separated by ';'
5113 - variable substitution using "... ${name} ..." syntax
5114 - special characters ('$', ';') can be escaped by prefixing with '\',
5116 setenv bootcmd bootm \${address}
5117 - You can also escape text by enclosing in single apostrophes, for example:
5118 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5123 - similar to Bourne shell, with control structures like
5124 if...then...else...fi, for...do...done; while...do...done,
5125 until...do...done, ...
5126 - supports environment ("global") variables (through setenv / saveenv
5127 commands) and local shell variables (through standard shell syntax
5128 "name=value"); only environment variables can be used with "run"
5134 (1) If a command line (or an environment variable executed by a "run"
5135 command) contains several commands separated by semicolon, and
5136 one of these commands fails, then the remaining commands will be
5139 (2) If you execute several variables with one call to run (i. e.
5140 calling run with a list of variables as arguments), any failing
5141 command will cause "run" to terminate, i. e. the remaining
5142 variables are not executed.
5144 Note for Redundant Ethernet Interfaces:
5145 =======================================
5147 Some boards come with redundant Ethernet interfaces; U-Boot supports
5148 such configurations and is capable of automatic selection of a
5149 "working" interface when needed. MAC assignment works as follows:
5151 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5152 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5153 "eth1addr" (=>eth1), "eth2addr", ...
5155 If the network interface stores some valid MAC address (for instance
5156 in SROM), this is used as default address if there is NO correspon-
5157 ding setting in the environment; if the corresponding environment
5158 variable is set, this overrides the settings in the card; that means:
5160 o If the SROM has a valid MAC address, and there is no address in the
5161 environment, the SROM's address is used.
5163 o If there is no valid address in the SROM, and a definition in the
5164 environment exists, then the value from the environment variable is
5167 o If both the SROM and the environment contain a MAC address, and
5168 both addresses are the same, this MAC address is used.
5170 o If both the SROM and the environment contain a MAC address, and the
5171 addresses differ, the value from the environment is used and a
5174 o If neither SROM nor the environment contain a MAC address, an error
5175 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5176 a random, locally-assigned MAC is used.
5178 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5179 will be programmed into hardware as part of the initialization process. This
5180 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5181 The naming convention is as follows:
5182 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5187 U-Boot is capable of booting (and performing other auxiliary operations on)
5188 images in two formats:
5190 New uImage format (FIT)
5191 -----------------------
5193 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5194 to Flattened Device Tree). It allows the use of images with multiple
5195 components (several kernels, ramdisks, etc.), with contents protected by
5196 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5202 Old image format is based on binary files which can be basically anything,
5203 preceded by a special header; see the definitions in include/image.h for
5204 details; basically, the header defines the following image properties:
5206 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5207 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5208 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5209 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5211 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5212 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5213 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5214 * Compression Type (uncompressed, gzip, bzip2)
5220 The header is marked by a special Magic Number, and both the header
5221 and the data portions of the image are secured against corruption by
5228 Although U-Boot should support any OS or standalone application
5229 easily, the main focus has always been on Linux during the design of
5232 U-Boot includes many features that so far have been part of some
5233 special "boot loader" code within the Linux kernel. Also, any
5234 "initrd" images to be used are no longer part of one big Linux image;
5235 instead, kernel and "initrd" are separate images. This implementation
5236 serves several purposes:
5238 - the same features can be used for other OS or standalone
5239 applications (for instance: using compressed images to reduce the
5240 Flash memory footprint)
5242 - it becomes much easier to port new Linux kernel versions because
5243 lots of low-level, hardware dependent stuff are done by U-Boot
5245 - the same Linux kernel image can now be used with different "initrd"
5246 images; of course this also means that different kernel images can
5247 be run with the same "initrd". This makes testing easier (you don't
5248 have to build a new "zImage.initrd" Linux image when you just
5249 change a file in your "initrd"). Also, a field-upgrade of the
5250 software is easier now.
5256 Porting Linux to U-Boot based systems:
5257 ---------------------------------------
5259 U-Boot cannot save you from doing all the necessary modifications to
5260 configure the Linux device drivers for use with your target hardware
5261 (no, we don't intend to provide a full virtual machine interface to
5264 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5266 Just make sure your machine specific header file (for instance
5267 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5268 Information structure as we define in include/asm-<arch>/u-boot.h,
5269 and make sure that your definition of IMAP_ADDR uses the same value
5270 as your U-Boot configuration in CONFIG_SYS_IMMR.
5272 Note that U-Boot now has a driver model, a unified model for drivers.
5273 If you are adding a new driver, plumb it into driver model. If there
5274 is no uclass available, you are encouraged to create one. See
5278 Configuring the Linux kernel:
5279 -----------------------------
5281 No specific requirements for U-Boot. Make sure you have some root
5282 device (initial ramdisk, NFS) for your target system.
5285 Building a Linux Image:
5286 -----------------------
5288 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5289 not used. If you use recent kernel source, a new build target
5290 "uImage" will exist which automatically builds an image usable by
5291 U-Boot. Most older kernels also have support for a "pImage" target,
5292 which was introduced for our predecessor project PPCBoot and uses a
5293 100% compatible format.
5297 make TQM850L_defconfig
5302 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5303 encapsulate a compressed Linux kernel image with header information,
5304 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5306 * build a standard "vmlinux" kernel image (in ELF binary format):
5308 * convert the kernel into a raw binary image:
5310 ${CROSS_COMPILE}-objcopy -O binary \
5311 -R .note -R .comment \
5312 -S vmlinux linux.bin
5314 * compress the binary image:
5318 * package compressed binary image for U-Boot:
5320 mkimage -A ppc -O linux -T kernel -C gzip \
5321 -a 0 -e 0 -n "Linux Kernel Image" \
5322 -d linux.bin.gz uImage
5325 The "mkimage" tool can also be used to create ramdisk images for use
5326 with U-Boot, either separated from the Linux kernel image, or
5327 combined into one file. "mkimage" encapsulates the images with a 64
5328 byte header containing information about target architecture,
5329 operating system, image type, compression method, entry points, time
5330 stamp, CRC32 checksums, etc.
5332 "mkimage" can be called in two ways: to verify existing images and
5333 print the header information, or to build new images.
5335 In the first form (with "-l" option) mkimage lists the information
5336 contained in the header of an existing U-Boot image; this includes
5337 checksum verification:
5339 tools/mkimage -l image
5340 -l ==> list image header information
5342 The second form (with "-d" option) is used to build a U-Boot image
5343 from a "data file" which is used as image payload:
5345 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5346 -n name -d data_file image
5347 -A ==> set architecture to 'arch'
5348 -O ==> set operating system to 'os'
5349 -T ==> set image type to 'type'
5350 -C ==> set compression type 'comp'
5351 -a ==> set load address to 'addr' (hex)
5352 -e ==> set entry point to 'ep' (hex)
5353 -n ==> set image name to 'name'
5354 -d ==> use image data from 'datafile'
5356 Right now, all Linux kernels for PowerPC systems use the same load
5357 address (0x00000000), but the entry point address depends on the
5360 - 2.2.x kernels have the entry point at 0x0000000C,
5361 - 2.3.x and later kernels have the entry point at 0x00000000.
5363 So a typical call to build a U-Boot image would read:
5365 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5366 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5367 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5368 > examples/uImage.TQM850L
5369 Image Name: 2.4.4 kernel for TQM850L
5370 Created: Wed Jul 19 02:34:59 2000
5371 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5372 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5373 Load Address: 0x00000000
5374 Entry Point: 0x00000000
5376 To verify the contents of the image (or check for corruption):
5378 -> tools/mkimage -l examples/uImage.TQM850L
5379 Image Name: 2.4.4 kernel for TQM850L
5380 Created: Wed Jul 19 02:34:59 2000
5381 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5382 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5383 Load Address: 0x00000000
5384 Entry Point: 0x00000000
5386 NOTE: for embedded systems where boot time is critical you can trade
5387 speed for memory and install an UNCOMPRESSED image instead: this
5388 needs more space in Flash, but boots much faster since it does not
5389 need to be uncompressed:
5391 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5392 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5393 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5394 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5395 > examples/uImage.TQM850L-uncompressed
5396 Image Name: 2.4.4 kernel for TQM850L
5397 Created: Wed Jul 19 02:34:59 2000
5398 Image Type: PowerPC Linux Kernel Image (uncompressed)
5399 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5400 Load Address: 0x00000000
5401 Entry Point: 0x00000000
5404 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5405 when your kernel is intended to use an initial ramdisk:
5407 -> tools/mkimage -n 'Simple Ramdisk Image' \
5408 > -A ppc -O linux -T ramdisk -C gzip \
5409 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5410 Image Name: Simple Ramdisk Image
5411 Created: Wed Jan 12 14:01:50 2000
5412 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5413 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5414 Load Address: 0x00000000
5415 Entry Point: 0x00000000
5417 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5418 option performs the converse operation of the mkimage's second form (the "-d"
5419 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5422 tools/dumpimage -i image -T type -p position data_file
5423 -i ==> extract from the 'image' a specific 'data_file'
5424 -T ==> set image type to 'type'
5425 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5428 Installing a Linux Image:
5429 -------------------------
5431 To downloading a U-Boot image over the serial (console) interface,
5432 you must convert the image to S-Record format:
5434 objcopy -I binary -O srec examples/image examples/image.srec
5436 The 'objcopy' does not understand the information in the U-Boot
5437 image header, so the resulting S-Record file will be relative to
5438 address 0x00000000. To load it to a given address, you need to
5439 specify the target address as 'offset' parameter with the 'loads'
5442 Example: install the image to address 0x40100000 (which on the
5443 TQM8xxL is in the first Flash bank):
5445 => erase 40100000 401FFFFF
5451 ## Ready for S-Record download ...
5452 ~>examples/image.srec
5453 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5455 15989 15990 15991 15992
5456 [file transfer complete]
5458 ## Start Addr = 0x00000000
5461 You can check the success of the download using the 'iminfo' command;
5462 this includes a checksum verification so you can be sure no data
5463 corruption happened:
5467 ## Checking Image at 40100000 ...
5468 Image Name: 2.2.13 for initrd on TQM850L
5469 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5470 Data Size: 335725 Bytes = 327 kB = 0 MB
5471 Load Address: 00000000
5472 Entry Point: 0000000c
5473 Verifying Checksum ... OK
5479 The "bootm" command is used to boot an application that is stored in
5480 memory (RAM or Flash). In case of a Linux kernel image, the contents
5481 of the "bootargs" environment variable is passed to the kernel as
5482 parameters. You can check and modify this variable using the
5483 "printenv" and "setenv" commands:
5486 => printenv bootargs
5487 bootargs=root=/dev/ram
5489 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5491 => printenv bootargs
5492 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5495 ## Booting Linux kernel at 40020000 ...
5496 Image Name: 2.2.13 for NFS on TQM850L
5497 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5498 Data Size: 381681 Bytes = 372 kB = 0 MB
5499 Load Address: 00000000
5500 Entry Point: 0000000c
5501 Verifying Checksum ... OK
5502 Uncompressing Kernel Image ... OK
5503 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
5504 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5505 time_init: decrementer frequency = 187500000/60
5506 Calibrating delay loop... 49.77 BogoMIPS
5507 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5510 If you want to boot a Linux kernel with initial RAM disk, you pass
5511 the memory addresses of both the kernel and the initrd image (PPBCOOT
5512 format!) to the "bootm" command:
5514 => imi 40100000 40200000
5516 ## Checking Image at 40100000 ...
5517 Image Name: 2.2.13 for initrd on TQM850L
5518 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5519 Data Size: 335725 Bytes = 327 kB = 0 MB
5520 Load Address: 00000000
5521 Entry Point: 0000000c
5522 Verifying Checksum ... OK
5524 ## Checking Image at 40200000 ...
5525 Image Name: Simple Ramdisk Image
5526 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5527 Data Size: 566530 Bytes = 553 kB = 0 MB
5528 Load Address: 00000000
5529 Entry Point: 00000000
5530 Verifying Checksum ... OK
5532 => bootm 40100000 40200000
5533 ## Booting Linux kernel at 40100000 ...
5534 Image Name: 2.2.13 for initrd on TQM850L
5535 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5536 Data Size: 335725 Bytes = 327 kB = 0 MB
5537 Load Address: 00000000
5538 Entry Point: 0000000c
5539 Verifying Checksum ... OK
5540 Uncompressing Kernel Image ... OK
5541 ## Loading RAMDisk Image at 40200000 ...
5542 Image Name: Simple Ramdisk Image
5543 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5544 Data Size: 566530 Bytes = 553 kB = 0 MB
5545 Load Address: 00000000
5546 Entry Point: 00000000
5547 Verifying Checksum ... OK
5548 Loading Ramdisk ... OK
5549 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
5550 Boot arguments: root=/dev/ram
5551 time_init: decrementer frequency = 187500000/60
5552 Calibrating delay loop... 49.77 BogoMIPS
5554 RAMDISK: Compressed image found at block 0
5555 VFS: Mounted root (ext2 filesystem).
5559 Boot Linux and pass a flat device tree:
5562 First, U-Boot must be compiled with the appropriate defines. See the section
5563 titled "Linux Kernel Interface" above for a more in depth explanation. The
5564 following is an example of how to start a kernel and pass an updated
5570 oft=oftrees/mpc8540ads.dtb
5571 => tftp $oftaddr $oft
5572 Speed: 1000, full duplex
5574 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5575 Filename 'oftrees/mpc8540ads.dtb'.
5576 Load address: 0x300000
5579 Bytes transferred = 4106 (100a hex)
5580 => tftp $loadaddr $bootfile
5581 Speed: 1000, full duplex
5583 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5585 Load address: 0x200000
5586 Loading:############
5588 Bytes transferred = 1029407 (fb51f hex)
5593 => bootm $loadaddr - $oftaddr
5594 ## Booting image at 00200000 ...
5595 Image Name: Linux-2.6.17-dirty
5596 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5597 Data Size: 1029343 Bytes = 1005.2 kB
5598 Load Address: 00000000
5599 Entry Point: 00000000
5600 Verifying Checksum ... OK
5601 Uncompressing Kernel Image ... OK
5602 Booting using flat device tree at 0x300000
5603 Using MPC85xx ADS machine description
5604 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5608 More About U-Boot Image Types:
5609 ------------------------------
5611 U-Boot supports the following image types:
5613 "Standalone Programs" are directly runnable in the environment
5614 provided by U-Boot; it is expected that (if they behave
5615 well) you can continue to work in U-Boot after return from
5616 the Standalone Program.
5617 "OS Kernel Images" are usually images of some Embedded OS which
5618 will take over control completely. Usually these programs
5619 will install their own set of exception handlers, device
5620 drivers, set up the MMU, etc. - this means, that you cannot
5621 expect to re-enter U-Boot except by resetting the CPU.
5622 "RAMDisk Images" are more or less just data blocks, and their
5623 parameters (address, size) are passed to an OS kernel that is
5625 "Multi-File Images" contain several images, typically an OS
5626 (Linux) kernel image and one or more data images like
5627 RAMDisks. This construct is useful for instance when you want
5628 to boot over the network using BOOTP etc., where the boot
5629 server provides just a single image file, but you want to get
5630 for instance an OS kernel and a RAMDisk image.
5632 "Multi-File Images" start with a list of image sizes, each
5633 image size (in bytes) specified by an "uint32_t" in network
5634 byte order. This list is terminated by an "(uint32_t)0".
5635 Immediately after the terminating 0 follow the images, one by
5636 one, all aligned on "uint32_t" boundaries (size rounded up to
5637 a multiple of 4 bytes).
5639 "Firmware Images" are binary images containing firmware (like
5640 U-Boot or FPGA images) which usually will be programmed to
5643 "Script files" are command sequences that will be executed by
5644 U-Boot's command interpreter; this feature is especially
5645 useful when you configure U-Boot to use a real shell (hush)
5646 as command interpreter.
5648 Booting the Linux zImage:
5649 -------------------------
5651 On some platforms, it's possible to boot Linux zImage. This is done
5652 using the "bootz" command. The syntax of "bootz" command is the same
5653 as the syntax of "bootm" command.
5655 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5656 kernel with raw initrd images. The syntax is slightly different, the
5657 address of the initrd must be augmented by it's size, in the following
5658 format: "<initrd addres>:<initrd size>".
5664 One of the features of U-Boot is that you can dynamically load and
5665 run "standalone" applications, which can use some resources of
5666 U-Boot like console I/O functions or interrupt services.
5668 Two simple examples are included with the sources:
5673 'examples/hello_world.c' contains a small "Hello World" Demo
5674 application; it is automatically compiled when you build U-Boot.
5675 It's configured to run at address 0x00040004, so you can play with it
5679 ## Ready for S-Record download ...
5680 ~>examples/hello_world.srec
5681 1 2 3 4 5 6 7 8 9 10 11 ...
5682 [file transfer complete]
5684 ## Start Addr = 0x00040004
5686 => go 40004 Hello World! This is a test.
5687 ## Starting application at 0x00040004 ...
5698 Hit any key to exit ...
5700 ## Application terminated, rc = 0x0
5702 Another example, which demonstrates how to register a CPM interrupt
5703 handler with the U-Boot code, can be found in 'examples/timer.c'.
5704 Here, a CPM timer is set up to generate an interrupt every second.
5705 The interrupt service routine is trivial, just printing a '.'
5706 character, but this is just a demo program. The application can be
5707 controlled by the following keys:
5709 ? - print current values og the CPM Timer registers
5710 b - enable interrupts and start timer
5711 e - stop timer and disable interrupts
5712 q - quit application
5715 ## Ready for S-Record download ...
5716 ~>examples/timer.srec
5717 1 2 3 4 5 6 7 8 9 10 11 ...
5718 [file transfer complete]
5720 ## Start Addr = 0x00040004
5723 ## Starting application at 0x00040004 ...
5726 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5729 [q, b, e, ?] Set interval 1000000 us
5732 [q, b, e, ?] ........
5733 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5736 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5739 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5742 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5744 [q, b, e, ?] ...Stopping timer
5746 [q, b, e, ?] ## Application terminated, rc = 0x0
5752 Over time, many people have reported problems when trying to use the
5753 "minicom" terminal emulation program for serial download. I (wd)
5754 consider minicom to be broken, and recommend not to use it. Under
5755 Unix, I recommend to use C-Kermit for general purpose use (and
5756 especially for kermit binary protocol download ("loadb" command), and
5757 use "cu" for S-Record download ("loads" command). See
5758 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5759 for help with kermit.
5762 Nevertheless, if you absolutely want to use it try adding this
5763 configuration to your "File transfer protocols" section:
5765 Name Program Name U/D FullScr IO-Red. Multi
5766 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5767 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5773 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5774 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5776 Building requires a cross environment; it is known to work on
5777 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5778 need gmake since the Makefiles are not compatible with BSD make).
5779 Note that the cross-powerpc package does not install include files;
5780 attempting to build U-Boot will fail because <machine/ansi.h> is
5781 missing. This file has to be installed and patched manually:
5783 # cd /usr/pkg/cross/powerpc-netbsd/include
5785 # ln -s powerpc machine
5786 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5787 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5789 Native builds *don't* work due to incompatibilities between native
5790 and U-Boot include files.
5792 Booting assumes that (the first part of) the image booted is a
5793 stage-2 loader which in turn loads and then invokes the kernel
5794 proper. Loader sources will eventually appear in the NetBSD source
5795 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5796 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5799 Implementation Internals:
5800 =========================
5802 The following is not intended to be a complete description of every
5803 implementation detail. However, it should help to understand the
5804 inner workings of U-Boot and make it easier to port it to custom
5808 Initial Stack, Global Data:
5809 ---------------------------
5811 The implementation of U-Boot is complicated by the fact that U-Boot
5812 starts running out of ROM (flash memory), usually without access to
5813 system RAM (because the memory controller is not initialized yet).
5814 This means that we don't have writable Data or BSS segments, and BSS
5815 is not initialized as zero. To be able to get a C environment working
5816 at all, we have to allocate at least a minimal stack. Implementation
5817 options for this are defined and restricted by the CPU used: Some CPU
5818 models provide on-chip memory (like the IMMR area on MPC8xx and
5819 MPC826x processors), on others (parts of) the data cache can be
5820 locked as (mis-) used as memory, etc.
5822 Chris Hallinan posted a good summary of these issues to the
5823 U-Boot mailing list:
5825 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5826 From: "Chris Hallinan" <clh@net1plus.com>
5827 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5830 Correct me if I'm wrong, folks, but the way I understand it
5831 is this: Using DCACHE as initial RAM for Stack, etc, does not
5832 require any physical RAM backing up the cache. The cleverness
5833 is that the cache is being used as a temporary supply of
5834 necessary storage before the SDRAM controller is setup. It's
5835 beyond the scope of this list to explain the details, but you
5836 can see how this works by studying the cache architecture and
5837 operation in the architecture and processor-specific manuals.
5839 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5840 is another option for the system designer to use as an
5841 initial stack/RAM area prior to SDRAM being available. Either
5842 option should work for you. Using CS 4 should be fine if your
5843 board designers haven't used it for something that would
5844 cause you grief during the initial boot! It is frequently not
5847 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5848 with your processor/board/system design. The default value
5849 you will find in any recent u-boot distribution in
5850 walnut.h should work for you. I'd set it to a value larger
5851 than your SDRAM module. If you have a 64MB SDRAM module, set
5852 it above 400_0000. Just make sure your board has no resources
5853 that are supposed to respond to that address! That code in
5854 start.S has been around a while and should work as is when
5855 you get the config right.
5860 It is essential to remember this, since it has some impact on the C
5861 code for the initialization procedures:
5863 * Initialized global data (data segment) is read-only. Do not attempt
5866 * Do not use any uninitialized global data (or implicitly initialized
5867 as zero data - BSS segment) at all - this is undefined, initiali-
5868 zation is performed later (when relocating to RAM).
5870 * Stack space is very limited. Avoid big data buffers or things like
5873 Having only the stack as writable memory limits means we cannot use
5874 normal global data to share information between the code. But it
5875 turned out that the implementation of U-Boot can be greatly
5876 simplified by making a global data structure (gd_t) available to all
5877 functions. We could pass a pointer to this data as argument to _all_
5878 functions, but this would bloat the code. Instead we use a feature of
5879 the GCC compiler (Global Register Variables) to share the data: we
5880 place a pointer (gd) to the global data into a register which we
5881 reserve for this purpose.
5883 When choosing a register for such a purpose we are restricted by the
5884 relevant (E)ABI specifications for the current architecture, and by
5885 GCC's implementation.
5887 For PowerPC, the following registers have specific use:
5889 R2: reserved for system use
5890 R3-R4: parameter passing and return values
5891 R5-R10: parameter passing
5892 R13: small data area pointer
5896 (U-Boot also uses R12 as internal GOT pointer. r12
5897 is a volatile register so r12 needs to be reset when
5898 going back and forth between asm and C)
5900 ==> U-Boot will use R2 to hold a pointer to the global data
5902 Note: on PPC, we could use a static initializer (since the
5903 address of the global data structure is known at compile time),
5904 but it turned out that reserving a register results in somewhat
5905 smaller code - although the code savings are not that big (on
5906 average for all boards 752 bytes for the whole U-Boot image,
5907 624 text + 127 data).
5909 On ARM, the following registers are used:
5911 R0: function argument word/integer result
5912 R1-R3: function argument word
5913 R9: platform specific
5914 R10: stack limit (used only if stack checking is enabled)
5915 R11: argument (frame) pointer
5916 R12: temporary workspace
5919 R15: program counter
5921 ==> U-Boot will use R9 to hold a pointer to the global data
5923 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5925 On Nios II, the ABI is documented here:
5926 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5928 ==> U-Boot will use gp to hold a pointer to the global data
5930 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5931 to access small data sections, so gp is free.
5933 On NDS32, the following registers are used:
5935 R0-R1: argument/return
5937 R15: temporary register for assembler
5938 R16: trampoline register
5939 R28: frame pointer (FP)
5940 R29: global pointer (GP)
5941 R30: link register (LP)
5942 R31: stack pointer (SP)
5943 PC: program counter (PC)
5945 ==> U-Boot will use R10 to hold a pointer to the global data
5947 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5948 or current versions of GCC may "optimize" the code too much.
5953 U-Boot runs in system state and uses physical addresses, i.e. the
5954 MMU is not used either for address mapping nor for memory protection.
5956 The available memory is mapped to fixed addresses using the memory
5957 controller. In this process, a contiguous block is formed for each
5958 memory type (Flash, SDRAM, SRAM), even when it consists of several
5959 physical memory banks.
5961 U-Boot is installed in the first 128 kB of the first Flash bank (on
5962 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5963 booting and sizing and initializing DRAM, the code relocates itself
5964 to the upper end of DRAM. Immediately below the U-Boot code some
5965 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5966 configuration setting]. Below that, a structure with global Board
5967 Info data is placed, followed by the stack (growing downward).
5969 Additionally, some exception handler code is copied to the low 8 kB
5970 of DRAM (0x00000000 ... 0x00001FFF).
5972 So a typical memory configuration with 16 MB of DRAM could look like
5975 0x0000 0000 Exception Vector code
5978 0x0000 2000 Free for Application Use
5984 0x00FB FF20 Monitor Stack (Growing downward)
5985 0x00FB FFAC Board Info Data and permanent copy of global data
5986 0x00FC 0000 Malloc Arena
5989 0x00FE 0000 RAM Copy of Monitor Code
5990 ... eventually: LCD or video framebuffer
5991 ... eventually: pRAM (Protected RAM - unchanged by reset)
5992 0x00FF FFFF [End of RAM]
5995 System Initialization:
5996 ----------------------
5998 In the reset configuration, U-Boot starts at the reset entry point
5999 (on most PowerPC systems at address 0x00000100). Because of the reset
6000 configuration for CS0# this is a mirror of the on board Flash memory.
6001 To be able to re-map memory U-Boot then jumps to its link address.
6002 To be able to implement the initialization code in C, a (small!)
6003 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6004 which provide such a feature like MPC8xx or MPC8260), or in a locked
6005 part of the data cache. After that, U-Boot initializes the CPU core,
6006 the caches and the SIU.
6008 Next, all (potentially) available memory banks are mapped using a
6009 preliminary mapping. For example, we put them on 512 MB boundaries
6010 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6011 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6012 programmed for SDRAM access. Using the temporary configuration, a
6013 simple memory test is run that determines the size of the SDRAM
6016 When there is more than one SDRAM bank, and the banks are of
6017 different size, the largest is mapped first. For equal size, the first
6018 bank (CS2#) is mapped first. The first mapping is always for address
6019 0x00000000, with any additional banks following immediately to create
6020 contiguous memory starting from 0.
6022 Then, the monitor installs itself at the upper end of the SDRAM area
6023 and allocates memory for use by malloc() and for the global Board
6024 Info data; also, the exception vector code is copied to the low RAM
6025 pages, and the final stack is set up.
6027 Only after this relocation will you have a "normal" C environment;
6028 until that you are restricted in several ways, mostly because you are
6029 running from ROM, and because the code will have to be relocated to a
6033 U-Boot Porting Guide:
6034 ----------------------
6036 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6040 int main(int argc, char *argv[])
6042 sighandler_t no_more_time;
6044 signal(SIGALRM, no_more_time);
6045 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6047 if (available_money > available_manpower) {
6048 Pay consultant to port U-Boot;
6052 Download latest U-Boot source;
6054 Subscribe to u-boot mailing list;
6057 email("Hi, I am new to U-Boot, how do I get started?");
6060 Read the README file in the top level directory;
6061 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6062 Read applicable doc/*.README;
6063 Read the source, Luke;
6064 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6067 if (available_money > toLocalCurrency ($2500))
6070 Add a lot of aggravation and time;
6072 if (a similar board exists) { /* hopefully... */
6073 cp -a board/<similar> board/<myboard>
6074 cp include/configs/<similar>.h include/configs/<myboard>.h
6076 Create your own board support subdirectory;
6077 Create your own board include/configs/<myboard>.h file;
6079 Edit new board/<myboard> files
6080 Edit new include/configs/<myboard>.h
6085 Add / modify source code;
6089 email("Hi, I am having problems...");
6091 Send patch file to the U-Boot email list;
6092 if (reasonable critiques)
6093 Incorporate improvements from email list code review;
6095 Defend code as written;
6101 void no_more_time (int sig)
6110 All contributions to U-Boot should conform to the Linux kernel
6111 coding style; see the file "Documentation/CodingStyle" and the script
6112 "scripts/Lindent" in your Linux kernel source directory.
6114 Source files originating from a different project (for example the
6115 MTD subsystem) are generally exempt from these guidelines and are not
6116 reformatted to ease subsequent migration to newer versions of those
6119 Please note that U-Boot is implemented in C (and to some small parts in
6120 Assembler); no C++ is used, so please do not use C++ style comments (//)
6123 Please also stick to the following formatting rules:
6124 - remove any trailing white space
6125 - use TAB characters for indentation and vertical alignment, not spaces
6126 - make sure NOT to use DOS '\r\n' line feeds
6127 - do not add more than 2 consecutive empty lines to source files
6128 - do not add trailing empty lines to source files
6130 Submissions which do not conform to the standards may be returned
6131 with a request to reformat the changes.
6137 Since the number of patches for U-Boot is growing, we need to
6138 establish some rules. Submissions which do not conform to these rules
6139 may be rejected, even when they contain important and valuable stuff.
6141 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6143 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6144 see http://lists.denx.de/mailman/listinfo/u-boot
6146 When you send a patch, please include the following information with
6149 * For bug fixes: a description of the bug and how your patch fixes
6150 this bug. Please try to include a way of demonstrating that the
6151 patch actually fixes something.
6153 * For new features: a description of the feature and your
6156 * A CHANGELOG entry as plaintext (separate from the patch)
6158 * For major contributions, add a MAINTAINERS file with your
6159 information and associated file and directory references.
6161 * When you add support for a new board, don't forget to add a
6162 maintainer e-mail address to the boards.cfg file, too.
6164 * If your patch adds new configuration options, don't forget to
6165 document these in the README file.
6167 * The patch itself. If you are using git (which is *strongly*
6168 recommended) you can easily generate the patch using the
6169 "git format-patch". If you then use "git send-email" to send it to
6170 the U-Boot mailing list, you will avoid most of the common problems
6171 with some other mail clients.
6173 If you cannot use git, use "diff -purN OLD NEW". If your version of
6174 diff does not support these options, then get the latest version of
6177 The current directory when running this command shall be the parent
6178 directory of the U-Boot source tree (i. e. please make sure that
6179 your patch includes sufficient directory information for the
6182 We prefer patches as plain text. MIME attachments are discouraged,
6183 and compressed attachments must not be used.
6185 * If one logical set of modifications affects or creates several
6186 files, all these changes shall be submitted in a SINGLE patch file.
6188 * Changesets that contain different, unrelated modifications shall be
6189 submitted as SEPARATE patches, one patch per changeset.
6194 * Before sending the patch, run the buildman script on your patched
6195 source tree and make sure that no errors or warnings are reported
6196 for any of the boards.
6198 * Keep your modifications to the necessary minimum: A patch
6199 containing several unrelated changes or arbitrary reformats will be
6200 returned with a request to re-formatting / split it.
6202 * If you modify existing code, make sure that your new code does not
6203 add to the memory footprint of the code ;-) Small is beautiful!
6204 When adding new features, these should compile conditionally only
6205 (using #ifdef), and the resulting code with the new feature
6206 disabled must not need more memory than the old code without your
6209 * Remember that there is a size limit of 100 kB per message on the
6210 u-boot mailing list. Bigger patches will be moderated. If they are
6211 reasonable and not too big, they will be acknowledged. But patches
6212 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob