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_BSP * Board specific commands
827 CONFIG_CMD_BOOTD bootd
828 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
829 CONFIG_CMD_CACHE * icache, dcache
830 CONFIG_CMD_CLK * clock command support
831 CONFIG_CMD_CONSOLE coninfo
832 CONFIG_CMD_CRC32 * crc32
833 CONFIG_CMD_DATE * support for RTC, date/time...
834 CONFIG_CMD_DHCP * DHCP support
835 CONFIG_CMD_DIAG * Diagnostics
836 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
837 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
838 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
839 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
840 CONFIG_CMD_DTT * Digital Therm and Thermostat
841 CONFIG_CMD_ECHO echo arguments
842 CONFIG_CMD_EDITENV edit env variable
843 CONFIG_CMD_EEPROM * EEPROM read/write support
844 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
845 CONFIG_CMD_ELF * bootelf, bootvx
846 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
847 CONFIG_CMD_ENV_FLAGS * display details about env flags
848 CONFIG_CMD_ENV_EXISTS * check existence of env variable
849 CONFIG_CMD_EXPORTENV * export the environment
850 CONFIG_CMD_EXT2 * ext2 command support
851 CONFIG_CMD_EXT4 * ext4 command support
852 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
853 that work for multiple fs types
854 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
855 CONFIG_CMD_SAVEENV saveenv
856 CONFIG_CMD_FDC * Floppy Disk Support
857 CONFIG_CMD_FAT * FAT command support
858 CONFIG_CMD_FLASH flinfo, erase, protect
859 CONFIG_CMD_FPGA FPGA device initialization support
860 CONFIG_CMD_FUSE * Device fuse support
861 CONFIG_CMD_GETTIME * Get time since boot
862 CONFIG_CMD_GO * the 'go' command (exec code)
863 CONFIG_CMD_GREPENV * search environment
864 CONFIG_CMD_HASH * calculate hash / digest
865 CONFIG_CMD_I2C * I2C serial bus support
866 CONFIG_CMD_IDE * IDE harddisk support
867 CONFIG_CMD_IMI iminfo
868 CONFIG_CMD_IMLS List all images found in NOR flash
869 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
870 CONFIG_CMD_IMMAP * IMMR dump support
871 CONFIG_CMD_IOTRACE * I/O tracing for debugging
872 CONFIG_CMD_IMPORTENV * import an environment
873 CONFIG_CMD_INI * import data from an ini file into the env
874 CONFIG_CMD_IRQ * irqinfo
875 CONFIG_CMD_ITEST Integer/string test of 2 values
876 CONFIG_CMD_JFFS2 * JFFS2 Support
877 CONFIG_CMD_KGDB * kgdb
878 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
879 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
881 CONFIG_CMD_LOADB loadb
882 CONFIG_CMD_LOADS loads
883 CONFIG_CMD_MD5SUM * print md5 message digest
884 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
885 CONFIG_CMD_MEMINFO * Display detailed memory information
886 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
888 CONFIG_CMD_MEMTEST * mtest
889 CONFIG_CMD_MISC Misc functions like sleep etc
890 CONFIG_CMD_MMC * MMC memory mapped support
891 CONFIG_CMD_MII * MII utility commands
892 CONFIG_CMD_MTDPARTS * MTD partition support
893 CONFIG_CMD_NAND * NAND support
894 CONFIG_CMD_NET bootp, tftpboot, rarpboot
895 CONFIG_CMD_NFS NFS support
896 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
897 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
898 CONFIG_CMD_PCI * pciinfo
899 CONFIG_CMD_PCMCIA * PCMCIA support
900 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
902 CONFIG_CMD_PORTIO * Port I/O
903 CONFIG_CMD_READ * Read raw data from partition
904 CONFIG_CMD_REGINFO * Register dump
905 CONFIG_CMD_RUN run command in env variable
906 CONFIG_CMD_SANDBOX * sb command to access sandbox features
907 CONFIG_CMD_SAVES * save S record dump
908 CONFIG_SCSI * SCSI Support
909 CONFIG_CMD_SDRAM * print SDRAM configuration information
910 (requires CONFIG_CMD_I2C)
911 CONFIG_CMD_SETGETDCR Support for DCR Register access
913 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
914 CONFIG_CMD_SHA1SUM * print sha1 memory digest
915 (requires CONFIG_CMD_MEMORY)
916 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
917 CONFIG_CMD_SOURCE "source" command Support
918 CONFIG_CMD_SPI * SPI serial bus support
919 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
920 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
921 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
922 CONFIG_CMD_TIMER * access to the system tick timer
923 CONFIG_CMD_USB * USB support
924 CONFIG_CMD_CDP * Cisco Discover Protocol support
925 CONFIG_CMD_MFSL * Microblaze FSL support
926 CONFIG_CMD_XIMG Load part of Multi Image
927 CONFIG_CMD_UUID * Generate random UUID or GUID string
929 EXAMPLE: If you want all functions except of network
930 support you can write:
932 #include "config_cmd_all.h"
933 #undef CONFIG_CMD_NET
936 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
938 Note: Don't enable the "icache" and "dcache" commands
939 (configuration option CONFIG_CMD_CACHE) unless you know
940 what you (and your U-Boot users) are doing. Data
941 cache cannot be enabled on systems like the 8xx or
942 8260 (where accesses to the IMMR region must be
943 uncached), and it cannot be disabled on all other
944 systems where we (mis-) use the data cache to hold an
945 initial stack and some data.
948 XXX - this list needs to get updated!
950 - Removal of commands
951 If no commands are needed to boot, you can disable
952 CONFIG_CMDLINE to remove them. In this case, the command line
953 will not be available, and when U-Boot wants to execute the
954 boot command (on start-up) it will call board_run_command()
955 instead. This can reduce image size significantly for very
956 simple boot procedures.
958 - Regular expression support:
960 If this variable is defined, U-Boot is linked against
961 the SLRE (Super Light Regular Expression) library,
962 which adds regex support to some commands, as for
963 example "env grep" and "setexpr".
967 If this variable is defined, U-Boot will use a device tree
968 to configure its devices, instead of relying on statically
969 compiled #defines in the board file. This option is
970 experimental and only available on a few boards. The device
971 tree is available in the global data as gd->fdt_blob.
973 U-Boot needs to get its device tree from somewhere. This can
974 be done using one of the two options below:
977 If this variable is defined, U-Boot will embed a device tree
978 binary in its image. This device tree file should be in the
979 board directory and called <soc>-<board>.dts. The binary file
980 is then picked up in board_init_f() and made available through
981 the global data structure as gd->blob.
984 If this variable is defined, U-Boot will build a device tree
985 binary. It will be called u-boot.dtb. Architecture-specific
986 code will locate it at run-time. Generally this works by:
988 cat u-boot.bin u-boot.dtb >image.bin
990 and in fact, U-Boot does this for you, creating a file called
991 u-boot-dtb.bin which is useful in the common case. You can
992 still use the individual files if you need something more
997 If this variable is defined, it enables watchdog
998 support for the SoC. There must be support in the SoC
999 specific code for a watchdog. For the 8xx and 8260
1000 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1001 register. When supported for a specific SoC is
1002 available, then no further board specific code should
1003 be needed to use it.
1006 When using a watchdog circuitry external to the used
1007 SoC, then define this variable and provide board
1008 specific code for the "hw_watchdog_reset" function.
1010 CONFIG_AT91_HW_WDT_TIMEOUT
1011 specify the timeout in seconds. default 2 seconds.
1014 CONFIG_VERSION_VARIABLE
1015 If this variable is defined, an environment variable
1016 named "ver" is created by U-Boot showing the U-Boot
1017 version as printed by the "version" command.
1018 Any change to this variable will be reverted at the
1023 When CONFIG_CMD_DATE is selected, the type of the RTC
1024 has to be selected, too. Define exactly one of the
1027 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1028 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1029 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1030 CONFIG_RTC_MC146818 - use MC146818 RTC
1031 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1032 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1033 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1034 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1035 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1036 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1037 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1038 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1039 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1042 Note that if the RTC uses I2C, then the I2C interface
1043 must also be configured. See I2C Support, below.
1046 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1048 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1049 chip-ngpio pairs that tell the PCA953X driver the number of
1050 pins supported by a particular chip.
1052 Note that if the GPIO device uses I2C, then the I2C interface
1053 must also be configured. See I2C Support, below.
1056 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1057 accesses and can checksum them or write a list of them out
1058 to memory. See the 'iotrace' command for details. This is
1059 useful for testing device drivers since it can confirm that
1060 the driver behaves the same way before and after a code
1061 change. Currently this is supported on sandbox and arm. To
1062 add support for your architecture, add '#include <iotrace.h>'
1063 to the bottom of arch/<arch>/include/asm/io.h and test.
1065 Example output from the 'iotrace stats' command is below.
1066 Note that if the trace buffer is exhausted, the checksum will
1067 still continue to operate.
1070 Start: 10000000 (buffer start address)
1071 Size: 00010000 (buffer size)
1072 Offset: 00000120 (current buffer offset)
1073 Output: 10000120 (start + offset)
1074 Count: 00000018 (number of trace records)
1075 CRC32: 9526fb66 (CRC32 of all trace records)
1077 - Timestamp Support:
1079 When CONFIG_TIMESTAMP is selected, the timestamp
1080 (date and time) of an image is printed by image
1081 commands like bootm or iminfo. This option is
1082 automatically enabled when you select CONFIG_CMD_DATE .
1084 - Partition Labels (disklabels) Supported:
1085 Zero or more of the following:
1086 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1087 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1088 Intel architecture, USB sticks, etc.
1089 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1090 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1091 bootloader. Note 2TB partition limit; see
1093 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1095 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1096 CONFIG_SCSI) you must configure support for at
1097 least one non-MTD partition type as well.
1100 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1101 board configurations files but used nowhere!
1103 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1104 be performed by calling the function
1105 ide_set_reset(int reset)
1106 which has to be defined in a board specific file
1111 Set this to enable ATAPI support.
1116 Set this to enable support for disks larger than 137GB
1117 Also look at CONFIG_SYS_64BIT_LBA.
1118 Whithout these , LBA48 support uses 32bit variables and will 'only'
1119 support disks up to 2.1TB.
1121 CONFIG_SYS_64BIT_LBA:
1122 When enabled, makes the IDE subsystem use 64bit sector addresses.
1126 At the moment only there is only support for the
1127 SYM53C8XX SCSI controller; define
1128 CONFIG_SCSI_SYM53C8XX to enable it.
1130 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1131 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1132 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1133 maximum numbers of LUNs, SCSI ID's and target
1135 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1137 The environment variable 'scsidevs' is set to the number of
1138 SCSI devices found during the last scan.
1140 - NETWORK Support (PCI):
1142 Support for Intel 8254x/8257x gigabit chips.
1145 Utility code for direct access to the SPI bus on Intel 8257x.
1146 This does not do anything useful unless you set at least one
1147 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1149 CONFIG_E1000_SPI_GENERIC
1150 Allow generic access to the SPI bus on the Intel 8257x, for
1151 example with the "sspi" command.
1154 Management command for E1000 devices. When used on devices
1155 with SPI support you can reprogram the EEPROM from U-Boot.
1158 Support for Intel 82557/82559/82559ER chips.
1159 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1160 write routine for first time initialisation.
1163 Support for Digital 2114x chips.
1164 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1165 modem chip initialisation (KS8761/QS6611).
1168 Support for National dp83815 chips.
1171 Support for National dp8382[01] gigabit chips.
1173 - NETWORK Support (other):
1175 CONFIG_DRIVER_AT91EMAC
1176 Support for AT91RM9200 EMAC.
1179 Define this to use reduced MII inteface
1181 CONFIG_DRIVER_AT91EMAC_QUIET
1182 If this defined, the driver is quiet.
1183 The driver doen't show link status messages.
1185 CONFIG_CALXEDA_XGMAC
1186 Support for the Calxeda XGMAC device
1189 Support for SMSC's LAN91C96 chips.
1191 CONFIG_LAN91C96_USE_32_BIT
1192 Define this to enable 32 bit addressing
1195 Support for SMSC's LAN91C111 chip
1197 CONFIG_SMC91111_BASE
1198 Define this to hold the physical address
1199 of the device (I/O space)
1201 CONFIG_SMC_USE_32_BIT
1202 Define this if data bus is 32 bits
1204 CONFIG_SMC_USE_IOFUNCS
1205 Define this to use i/o functions instead of macros
1206 (some hardware wont work with macros)
1208 CONFIG_DRIVER_TI_EMAC
1209 Support for davinci emac
1211 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1212 Define this if you have more then 3 PHYs.
1215 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1217 CONFIG_FTGMAC100_EGIGA
1218 Define this to use GE link update with gigabit PHY.
1219 Define this if FTGMAC100 is connected to gigabit PHY.
1220 If your system has 10/100 PHY only, it might not occur
1221 wrong behavior. Because PHY usually return timeout or
1222 useless data when polling gigabit status and gigabit
1223 control registers. This behavior won't affect the
1224 correctnessof 10/100 link speed update.
1227 Support for SMSC's LAN911x and LAN921x chips
1230 Define this to hold the physical address
1231 of the device (I/O space)
1233 CONFIG_SMC911X_32_BIT
1234 Define this if data bus is 32 bits
1236 CONFIG_SMC911X_16_BIT
1237 Define this if data bus is 16 bits. If your processor
1238 automatically converts one 32 bit word to two 16 bit
1239 words you may also try CONFIG_SMC911X_32_BIT.
1242 Support for Renesas on-chip Ethernet controller
1244 CONFIG_SH_ETHER_USE_PORT
1245 Define the number of ports to be used
1247 CONFIG_SH_ETHER_PHY_ADDR
1248 Define the ETH PHY's address
1250 CONFIG_SH_ETHER_CACHE_WRITEBACK
1251 If this option is set, the driver enables cache flush.
1255 Support for PWM module on the imx6.
1259 Support TPM devices.
1261 CONFIG_TPM_TIS_INFINEON
1262 Support for Infineon i2c bus TPM devices. Only one device
1263 per system is supported at this time.
1265 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1266 Define the burst count bytes upper limit
1269 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1271 CONFIG_TPM_ST33ZP24_I2C
1272 Support for STMicroelectronics ST33ZP24 I2C devices.
1273 Requires TPM_ST33ZP24 and I2C.
1275 CONFIG_TPM_ST33ZP24_SPI
1276 Support for STMicroelectronics ST33ZP24 SPI devices.
1277 Requires TPM_ST33ZP24 and SPI.
1279 CONFIG_TPM_ATMEL_TWI
1280 Support for Atmel TWI TPM device. Requires I2C support.
1283 Support for generic parallel port TPM devices. Only one device
1284 per system is supported at this time.
1286 CONFIG_TPM_TIS_BASE_ADDRESS
1287 Base address where the generic TPM device is mapped
1288 to. Contemporary x86 systems usually map it at
1292 Add tpm monitor functions.
1293 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1294 provides monitor access to authorized functions.
1297 Define this to enable the TPM support library which provides
1298 functional interfaces to some TPM commands.
1299 Requires support for a TPM device.
1301 CONFIG_TPM_AUTH_SESSIONS
1302 Define this to enable authorized functions in the TPM library.
1303 Requires CONFIG_TPM and CONFIG_SHA1.
1306 At the moment only the UHCI host controller is
1307 supported (PIP405, MIP405, MPC5200); define
1308 CONFIG_USB_UHCI to enable it.
1309 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1310 and define CONFIG_USB_STORAGE to enable the USB
1313 Supported are USB Keyboards and USB Floppy drives
1315 MPC5200 USB requires additional defines:
1317 for 528 MHz Clock: 0x0001bbbb
1321 for differential drivers: 0x00001000
1322 for single ended drivers: 0x00005000
1323 for differential drivers on PSC3: 0x00000100
1324 for single ended drivers on PSC3: 0x00004100
1325 CONFIG_SYS_USB_EVENT_POLL
1326 May be defined to allow interrupt polling
1327 instead of using asynchronous interrupts
1329 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1330 txfilltuning field in the EHCI controller on reset.
1332 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1333 HW module registers.
1336 Define the below if you wish to use the USB console.
1337 Once firmware is rebuilt from a serial console issue the
1338 command "setenv stdin usbtty; setenv stdout usbtty" and
1339 attach your USB cable. The Unix command "dmesg" should print
1340 it has found a new device. The environment variable usbtty
1341 can be set to gserial or cdc_acm to enable your device to
1342 appear to a USB host as a Linux gserial device or a
1343 Common Device Class Abstract Control Model serial device.
1344 If you select usbtty = gserial you should be able to enumerate
1346 # modprobe usbserial vendor=0xVendorID product=0xProductID
1347 else if using cdc_acm, simply setting the environment
1348 variable usbtty to be cdc_acm should suffice. The following
1349 might be defined in YourBoardName.h
1352 Define this to build a UDC device
1355 Define this to have a tty type of device available to
1356 talk to the UDC device
1359 Define this to enable the high speed support for usb
1360 device and usbtty. If this feature is enabled, a routine
1361 int is_usbd_high_speed(void)
1362 also needs to be defined by the driver to dynamically poll
1363 whether the enumeration has succeded at high speed or full
1366 CONFIG_SYS_CONSOLE_IS_IN_ENV
1367 Define this if you want stdin, stdout &/or stderr to
1371 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1372 Derive USB clock from external clock "blah"
1373 - CONFIG_SYS_USB_EXTC_CLK 0x02
1375 If you have a USB-IF assigned VendorID then you may wish to
1376 define your own vendor specific values either in BoardName.h
1377 or directly in usbd_vendor_info.h. If you don't define
1378 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1379 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1380 should pretend to be a Linux device to it's target host.
1382 CONFIG_USBD_MANUFACTURER
1383 Define this string as the name of your company for
1384 - CONFIG_USBD_MANUFACTURER "my company"
1386 CONFIG_USBD_PRODUCT_NAME
1387 Define this string as the name of your product
1388 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1390 CONFIG_USBD_VENDORID
1391 Define this as your assigned Vendor ID from the USB
1392 Implementors Forum. This *must* be a genuine Vendor ID
1393 to avoid polluting the USB namespace.
1394 - CONFIG_USBD_VENDORID 0xFFFF
1396 CONFIG_USBD_PRODUCTID
1397 Define this as the unique Product ID
1399 - CONFIG_USBD_PRODUCTID 0xFFFF
1401 - ULPI Layer Support:
1402 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1403 the generic ULPI layer. The generic layer accesses the ULPI PHY
1404 via the platform viewport, so you need both the genric layer and
1405 the viewport enabled. Currently only Chipidea/ARC based
1406 viewport is supported.
1407 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1408 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1409 If your ULPI phy needs a different reference clock than the
1410 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1411 the appropriate value in Hz.
1414 The MMC controller on the Intel PXA is supported. To
1415 enable this define CONFIG_MMC. The MMC can be
1416 accessed from the boot prompt by mapping the device
1417 to physical memory similar to flash. Command line is
1418 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1419 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1422 Support for Renesas on-chip MMCIF controller
1424 CONFIG_SH_MMCIF_ADDR
1425 Define the base address of MMCIF registers
1428 Define the clock frequency for MMCIF
1430 CONFIG_SUPPORT_EMMC_BOOT
1431 Enable some additional features of the eMMC boot partitions.
1433 CONFIG_SUPPORT_EMMC_RPMB
1434 Enable the commands for reading, writing and programming the
1435 key for the Replay Protection Memory Block partition in eMMC.
1437 - USB Device Firmware Update (DFU) class support:
1438 CONFIG_USB_FUNCTION_DFU
1439 This enables the USB portion of the DFU USB class
1442 This enables the command "dfu" which is used to have
1443 U-Boot create a DFU class device via USB. This command
1444 requires that the "dfu_alt_info" environment variable be
1445 set and define the alt settings to expose to the host.
1448 This enables support for exposing (e)MMC devices via DFU.
1451 This enables support for exposing NAND devices via DFU.
1454 This enables support for exposing RAM via DFU.
1455 Note: DFU spec refer to non-volatile memory usage, but
1456 allow usages beyond the scope of spec - here RAM usage,
1457 one that would help mostly the developer.
1459 CONFIG_SYS_DFU_DATA_BUF_SIZE
1460 Dfu transfer uses a buffer before writing data to the
1461 raw storage device. Make the size (in bytes) of this buffer
1462 configurable. The size of this buffer is also configurable
1463 through the "dfu_bufsiz" environment variable.
1465 CONFIG_SYS_DFU_MAX_FILE_SIZE
1466 When updating files rather than the raw storage device,
1467 we use a static buffer to copy the file into and then write
1468 the buffer once we've been given the whole file. Define
1469 this to the maximum filesize (in bytes) for the buffer.
1470 Default is 4 MiB if undefined.
1472 DFU_DEFAULT_POLL_TIMEOUT
1473 Poll timeout [ms], is the timeout a device can send to the
1474 host. The host must wait for this timeout before sending
1475 a subsequent DFU_GET_STATUS request to the device.
1477 DFU_MANIFEST_POLL_TIMEOUT
1478 Poll timeout [ms], which the device sends to the host when
1479 entering dfuMANIFEST state. Host waits this timeout, before
1480 sending again an USB request to the device.
1482 - USB Device Android Fastboot support:
1483 CONFIG_USB_FUNCTION_FASTBOOT
1484 This enables the USB part of the fastboot gadget
1487 This enables the command "fastboot" which enables the Android
1488 fastboot mode for the platform's USB device. Fastboot is a USB
1489 protocol for downloading images, flashing and device control
1490 used on Android devices.
1491 See doc/README.android-fastboot for more information.
1493 CONFIG_ANDROID_BOOT_IMAGE
1494 This enables support for booting images which use the Android
1495 image format header.
1497 CONFIG_FASTBOOT_BUF_ADDR
1498 The fastboot protocol requires a large memory buffer for
1499 downloads. Define this to the starting RAM address to use for
1502 CONFIG_FASTBOOT_BUF_SIZE
1503 The fastboot protocol requires a large memory buffer for
1504 downloads. This buffer should be as large as possible for a
1505 platform. Define this to the size available RAM for fastboot.
1507 CONFIG_FASTBOOT_FLASH
1508 The fastboot protocol includes a "flash" command for writing
1509 the downloaded image to a non-volatile storage device. Define
1510 this to enable the "fastboot flash" command.
1512 CONFIG_FASTBOOT_FLASH_MMC_DEV
1513 The fastboot "flash" command requires additional information
1514 regarding the non-volatile storage device. Define this to
1515 the eMMC device that fastboot should use to store the image.
1517 CONFIG_FASTBOOT_GPT_NAME
1518 The fastboot "flash" command supports writing the downloaded
1519 image to the Protective MBR and the Primary GUID Partition
1520 Table. (Additionally, this downloaded image is post-processed
1521 to generate and write the Backup GUID Partition Table.)
1522 This occurs when the specified "partition name" on the
1523 "fastboot flash" command line matches this value.
1524 The default is "gpt" if undefined.
1526 CONFIG_FASTBOOT_MBR_NAME
1527 The fastboot "flash" command supports writing the downloaded
1529 This occurs when the "partition name" specified on the
1530 "fastboot flash" command line matches this value.
1531 If not defined the default value "mbr" is used.
1533 - Journaling Flash filesystem support:
1535 Define these for a default partition on a NAND device
1537 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1538 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1539 Define these for a default partition on a NOR device
1541 - FAT(File Allocation Table) filesystem write function support:
1544 Define this to enable support for saving memory data as a
1545 file in FAT formatted partition.
1547 This will also enable the command "fatwrite" enabling the
1548 user to write files to FAT.
1550 - CBFS (Coreboot Filesystem) support:
1553 Define this to enable support for reading from a Coreboot
1554 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1557 - FAT(File Allocation Table) filesystem cluster size:
1558 CONFIG_FS_FAT_MAX_CLUSTSIZE
1560 Define the max cluster size for fat operations else
1561 a default value of 65536 will be defined.
1564 See Kconfig help for available keyboard drivers.
1568 Define this to enable a custom keyboard support.
1569 This simply calls drv_keyboard_init() which must be
1570 defined in your board-specific files. This option is deprecated
1571 and is only used by novena. For new boards, use driver model
1576 Enable the Freescale DIU video driver. Reference boards for
1577 SOCs that have a DIU should define this macro to enable DIU
1578 support, and should also define these other macros:
1584 CONFIG_VIDEO_SW_CURSOR
1585 CONFIG_VGA_AS_SINGLE_DEVICE
1587 CONFIG_VIDEO_BMP_LOGO
1589 The DIU driver will look for the 'video-mode' environment
1590 variable, and if defined, enable the DIU as a console during
1591 boot. See the documentation file doc/README.video for a
1592 description of this variable.
1594 - LCD Support: CONFIG_LCD
1596 Define this to enable LCD support (for output to LCD
1597 display); also select one of the supported displays
1598 by defining one of these:
1602 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1604 CONFIG_NEC_NL6448AC33:
1606 NEC NL6448AC33-18. Active, color, single scan.
1608 CONFIG_NEC_NL6448BC20
1610 NEC NL6448BC20-08. 6.5", 640x480.
1611 Active, color, single scan.
1613 CONFIG_NEC_NL6448BC33_54
1615 NEC NL6448BC33-54. 10.4", 640x480.
1616 Active, color, single scan.
1620 Sharp 320x240. Active, color, single scan.
1621 It isn't 16x9, and I am not sure what it is.
1623 CONFIG_SHARP_LQ64D341
1625 Sharp LQ64D341 display, 640x480.
1626 Active, color, single scan.
1630 HLD1045 display, 640x480.
1631 Active, color, single scan.
1635 Optrex CBL50840-2 NF-FW 99 22 M5
1637 Hitachi LMG6912RPFC-00T
1641 320x240. Black & white.
1643 Normally display is black on white background; define
1644 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1646 CONFIG_LCD_ALIGNMENT
1648 Normally the LCD is page-aligned (typically 4KB). If this is
1649 defined then the LCD will be aligned to this value instead.
1650 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1651 here, since it is cheaper to change data cache settings on
1652 a per-section basis.
1657 Sometimes, for example if the display is mounted in portrait
1658 mode or even if it's mounted landscape but rotated by 180degree,
1659 we need to rotate our content of the display relative to the
1660 framebuffer, so that user can read the messages which are
1662 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1663 initialized with a given rotation from "vl_rot" out of
1664 "vidinfo_t" which is provided by the board specific code.
1665 The value for vl_rot is coded as following (matching to
1666 fbcon=rotate:<n> linux-kernel commandline):
1667 0 = no rotation respectively 0 degree
1668 1 = 90 degree rotation
1669 2 = 180 degree rotation
1670 3 = 270 degree rotation
1672 If CONFIG_LCD_ROTATION is not defined, the console will be
1673 initialized with 0degree rotation.
1677 Support drawing of RLE8-compressed bitmaps on the LCD.
1681 Enables an 'i2c edid' command which can read EDID
1682 information over I2C from an attached LCD display.
1684 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1686 If this option is set, the environment is checked for
1687 a variable "splashimage". If found, the usual display
1688 of logo, copyright and system information on the LCD
1689 is suppressed and the BMP image at the address
1690 specified in "splashimage" is loaded instead. The
1691 console is redirected to the "nulldev", too. This
1692 allows for a "silent" boot where a splash screen is
1693 loaded very quickly after power-on.
1695 CONFIG_SPLASHIMAGE_GUARD
1697 If this option is set, then U-Boot will prevent the environment
1698 variable "splashimage" from being set to a problematic address
1699 (see doc/README.displaying-bmps).
1700 This option is useful for targets where, due to alignment
1701 restrictions, an improperly aligned BMP image will cause a data
1702 abort. If you think you will not have problems with unaligned
1703 accesses (for example because your toolchain prevents them)
1704 there is no need to set this option.
1706 CONFIG_SPLASH_SCREEN_ALIGN
1708 If this option is set the splash image can be freely positioned
1709 on the screen. Environment variable "splashpos" specifies the
1710 position as "x,y". If a positive number is given it is used as
1711 number of pixel from left/top. If a negative number is given it
1712 is used as number of pixel from right/bottom. You can also
1713 specify 'm' for centering the image.
1716 setenv splashpos m,m
1717 => image at center of screen
1719 setenv splashpos 30,20
1720 => image at x = 30 and y = 20
1722 setenv splashpos -10,m
1723 => vertically centered image
1724 at x = dspWidth - bmpWidth - 9
1726 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1728 If this option is set, additionally to standard BMP
1729 images, gzipped BMP images can be displayed via the
1730 splashscreen support or the bmp command.
1732 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1734 If this option is set, 8-bit RLE compressed BMP images
1735 can be displayed via the splashscreen support or the
1738 - Compression support:
1741 Enabled by default to support gzip compressed images.
1745 If this option is set, support for bzip2 compressed
1746 images is included. If not, only uncompressed and gzip
1747 compressed images are supported.
1749 NOTE: the bzip2 algorithm requires a lot of RAM, so
1750 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1755 If this option is set, support for lzma compressed
1758 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1759 requires an amount of dynamic memory that is given by the
1762 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1764 Where lc and lp stand for, respectively, Literal context bits
1765 and Literal pos bits.
1767 This value is upper-bounded by 14MB in the worst case. Anyway,
1768 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1769 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1770 a very small buffer.
1772 Use the lzmainfo tool to determinate the lc and lp values and
1773 then calculate the amount of needed dynamic memory (ensuring
1774 the appropriate CONFIG_SYS_MALLOC_LEN value).
1778 If this option is set, support for LZO compressed images
1784 The address of PHY on MII bus.
1786 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1788 The clock frequency of the MII bus
1792 If this option is set, support for speed/duplex
1793 detection of gigabit PHY is included.
1795 CONFIG_PHY_RESET_DELAY
1797 Some PHY like Intel LXT971A need extra delay after
1798 reset before any MII register access is possible.
1799 For such PHY, set this option to the usec delay
1800 required. (minimum 300usec for LXT971A)
1802 CONFIG_PHY_CMD_DELAY (ppc4xx)
1804 Some PHY like Intel LXT971A need extra delay after
1805 command issued before MII status register can be read
1810 Define a default value for the IP address to use for
1811 the default Ethernet interface, in case this is not
1812 determined through e.g. bootp.
1813 (Environment variable "ipaddr")
1815 - Server IP address:
1818 Defines a default value for the IP address of a TFTP
1819 server to contact when using the "tftboot" command.
1820 (Environment variable "serverip")
1822 CONFIG_KEEP_SERVERADDR
1824 Keeps the server's MAC address, in the env 'serveraddr'
1825 for passing to bootargs (like Linux's netconsole option)
1827 - Gateway IP address:
1830 Defines a default value for the IP address of the
1831 default router where packets to other networks are
1833 (Environment variable "gatewayip")
1838 Defines a default value for the subnet mask (or
1839 routing prefix) which is used to determine if an IP
1840 address belongs to the local subnet or needs to be
1841 forwarded through a router.
1842 (Environment variable "netmask")
1844 - Multicast TFTP Mode:
1847 Defines whether you want to support multicast TFTP as per
1848 rfc-2090; for example to work with atftp. Lets lots of targets
1849 tftp down the same boot image concurrently. Note: the Ethernet
1850 driver in use must provide a function: mcast() to join/leave a
1853 - BOOTP Recovery Mode:
1854 CONFIG_BOOTP_RANDOM_DELAY
1856 If you have many targets in a network that try to
1857 boot using BOOTP, you may want to avoid that all
1858 systems send out BOOTP requests at precisely the same
1859 moment (which would happen for instance at recovery
1860 from a power failure, when all systems will try to
1861 boot, thus flooding the BOOTP server. Defining
1862 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1863 inserted before sending out BOOTP requests. The
1864 following delays are inserted then:
1866 1st BOOTP request: delay 0 ... 1 sec
1867 2nd BOOTP request: delay 0 ... 2 sec
1868 3rd BOOTP request: delay 0 ... 4 sec
1870 BOOTP requests: delay 0 ... 8 sec
1872 CONFIG_BOOTP_ID_CACHE_SIZE
1874 BOOTP packets are uniquely identified using a 32-bit ID. The
1875 server will copy the ID from client requests to responses and
1876 U-Boot will use this to determine if it is the destination of
1877 an incoming response. Some servers will check that addresses
1878 aren't in use before handing them out (usually using an ARP
1879 ping) and therefore take up to a few hundred milliseconds to
1880 respond. Network congestion may also influence the time it
1881 takes for a response to make it back to the client. If that
1882 time is too long, U-Boot will retransmit requests. In order
1883 to allow earlier responses to still be accepted after these
1884 retransmissions, U-Boot's BOOTP client keeps a small cache of
1885 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1886 cache. The default is to keep IDs for up to four outstanding
1887 requests. Increasing this will allow U-Boot to accept offers
1888 from a BOOTP client in networks with unusually high latency.
1890 - DHCP Advanced Options:
1891 You can fine tune the DHCP functionality by defining
1892 CONFIG_BOOTP_* symbols:
1894 CONFIG_BOOTP_SUBNETMASK
1895 CONFIG_BOOTP_GATEWAY
1896 CONFIG_BOOTP_HOSTNAME
1897 CONFIG_BOOTP_NISDOMAIN
1898 CONFIG_BOOTP_BOOTPATH
1899 CONFIG_BOOTP_BOOTFILESIZE
1902 CONFIG_BOOTP_SEND_HOSTNAME
1903 CONFIG_BOOTP_NTPSERVER
1904 CONFIG_BOOTP_TIMEOFFSET
1905 CONFIG_BOOTP_VENDOREX
1906 CONFIG_BOOTP_MAY_FAIL
1908 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1909 environment variable, not the BOOTP server.
1911 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1912 after the configured retry count, the call will fail
1913 instead of starting over. This can be used to fail over
1914 to Link-local IP address configuration if the DHCP server
1917 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1918 serverip from a DHCP server, it is possible that more
1919 than one DNS serverip is offered to the client.
1920 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1921 serverip will be stored in the additional environment
1922 variable "dnsip2". The first DNS serverip is always
1923 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1926 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1927 to do a dynamic update of a DNS server. To do this, they
1928 need the hostname of the DHCP requester.
1929 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1930 of the "hostname" environment variable is passed as
1931 option 12 to the DHCP server.
1933 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1935 A 32bit value in microseconds for a delay between
1936 receiving a "DHCP Offer" and sending the "DHCP Request".
1937 This fixes a problem with certain DHCP servers that don't
1938 respond 100% of the time to a "DHCP request". E.g. On an
1939 AT91RM9200 processor running at 180MHz, this delay needed
1940 to be *at least* 15,000 usec before a Windows Server 2003
1941 DHCP server would reply 100% of the time. I recommend at
1942 least 50,000 usec to be safe. The alternative is to hope
1943 that one of the retries will be successful but note that
1944 the DHCP timeout and retry process takes a longer than
1947 - Link-local IP address negotiation:
1948 Negotiate with other link-local clients on the local network
1949 for an address that doesn't require explicit configuration.
1950 This is especially useful if a DHCP server cannot be guaranteed
1951 to exist in all environments that the device must operate.
1953 See doc/README.link-local for more information.
1956 CONFIG_CDP_DEVICE_ID
1958 The device id used in CDP trigger frames.
1960 CONFIG_CDP_DEVICE_ID_PREFIX
1962 A two character string which is prefixed to the MAC address
1967 A printf format string which contains the ascii name of
1968 the port. Normally is set to "eth%d" which sets
1969 eth0 for the first Ethernet, eth1 for the second etc.
1971 CONFIG_CDP_CAPABILITIES
1973 A 32bit integer which indicates the device capabilities;
1974 0x00000010 for a normal host which does not forwards.
1978 An ascii string containing the version of the software.
1982 An ascii string containing the name of the platform.
1986 A 32bit integer sent on the trigger.
1988 CONFIG_CDP_POWER_CONSUMPTION
1990 A 16bit integer containing the power consumption of the
1991 device in .1 of milliwatts.
1993 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1995 A byte containing the id of the VLAN.
1997 - Status LED: CONFIG_LED_STATUS
1999 Several configurations allow to display the current
2000 status using a LED. For instance, the LED will blink
2001 fast while running U-Boot code, stop blinking as
2002 soon as a reply to a BOOTP request was received, and
2003 start blinking slow once the Linux kernel is running
2004 (supported by a status LED driver in the Linux
2005 kernel). Defining CONFIG_LED_STATUS enables this
2010 CONFIG_LED_STATUS_GPIO
2011 The status LED can be connected to a GPIO pin.
2012 In such cases, the gpio_led driver can be used as a
2013 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2014 to include the gpio_led driver in the U-Boot binary.
2016 CONFIG_GPIO_LED_INVERTED_TABLE
2017 Some GPIO connected LEDs may have inverted polarity in which
2018 case the GPIO high value corresponds to LED off state and
2019 GPIO low value corresponds to LED on state.
2020 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2021 with a list of GPIO LEDs that have inverted polarity.
2023 - CAN Support: CONFIG_CAN_DRIVER
2025 Defining CONFIG_CAN_DRIVER enables CAN driver support
2026 on those systems that support this (optional)
2027 feature, like the TQM8xxL modules.
2029 - I2C Support: CONFIG_SYS_I2C
2031 This enable the NEW i2c subsystem, and will allow you to use
2032 i2c commands at the u-boot command line (as long as you set
2033 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2034 based realtime clock chips or other i2c devices. See
2035 common/cmd_i2c.c for a description of the command line
2038 ported i2c driver to the new framework:
2039 - drivers/i2c/soft_i2c.c:
2040 - activate first bus with CONFIG_SYS_I2C_SOFT define
2041 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2042 for defining speed and slave address
2043 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2044 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2045 for defining speed and slave address
2046 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2047 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2048 for defining speed and slave address
2049 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2050 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2051 for defining speed and slave address
2053 - drivers/i2c/fsl_i2c.c:
2054 - activate i2c driver with CONFIG_SYS_I2C_FSL
2055 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2056 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2057 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2059 - If your board supports a second fsl i2c bus, define
2060 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2061 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2062 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2065 - drivers/i2c/tegra_i2c.c:
2066 - activate this driver with CONFIG_SYS_I2C_TEGRA
2067 - This driver adds 4 i2c buses with a fix speed from
2068 100000 and the slave addr 0!
2070 - drivers/i2c/ppc4xx_i2c.c
2071 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2072 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2073 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2075 - drivers/i2c/i2c_mxc.c
2076 - activate this driver with CONFIG_SYS_I2C_MXC
2077 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2078 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2079 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2080 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2081 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2082 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2083 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2084 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2085 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2086 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2087 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2088 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2089 If those defines are not set, default value is 100000
2090 for speed, and 0 for slave.
2092 - drivers/i2c/rcar_i2c.c:
2093 - activate this driver with CONFIG_SYS_I2C_RCAR
2094 - This driver adds 4 i2c buses
2096 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2097 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2098 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2099 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2100 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2101 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2102 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2103 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2104 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2106 - drivers/i2c/sh_i2c.c:
2107 - activate this driver with CONFIG_SYS_I2C_SH
2108 - This driver adds from 2 to 5 i2c buses
2110 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2111 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2112 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2113 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2114 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2115 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2116 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2117 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2118 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2119 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2120 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2122 - drivers/i2c/omap24xx_i2c.c
2123 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2124 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2125 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2126 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2127 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2128 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2129 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2130 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2131 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2132 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2133 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2135 - drivers/i2c/zynq_i2c.c
2136 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2137 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2138 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2140 - drivers/i2c/s3c24x0_i2c.c:
2141 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2142 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2143 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2144 with a fix speed from 100000 and the slave addr 0!
2146 - drivers/i2c/ihs_i2c.c
2147 - activate this driver with CONFIG_SYS_I2C_IHS
2148 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2149 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2150 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2151 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2152 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2153 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2154 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2155 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2156 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2157 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2158 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2159 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2160 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2161 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2162 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2163 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2164 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2165 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2166 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2167 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2168 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2172 CONFIG_SYS_NUM_I2C_BUSES
2173 Hold the number of i2c buses you want to use.
2175 CONFIG_SYS_I2C_DIRECT_BUS
2176 define this, if you don't use i2c muxes on your hardware.
2177 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2180 CONFIG_SYS_I2C_MAX_HOPS
2181 define how many muxes are maximal consecutively connected
2182 on one i2c bus. If you not use i2c muxes, omit this
2185 CONFIG_SYS_I2C_BUSES
2186 hold a list of buses you want to use, only used if
2187 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2188 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2189 CONFIG_SYS_NUM_I2C_BUSES = 9:
2191 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2192 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2193 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2194 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2195 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2196 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2197 {1, {I2C_NULL_HOP}}, \
2198 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2199 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2203 bus 0 on adapter 0 without a mux
2204 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2205 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2206 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2207 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2208 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2209 bus 6 on adapter 1 without a mux
2210 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2211 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2213 If you do not have i2c muxes on your board, omit this define.
2215 - Legacy I2C Support: CONFIG_HARD_I2C
2217 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2218 provides the following compelling advantages:
2220 - more than one i2c adapter is usable
2221 - approved multibus support
2222 - better i2c mux support
2224 ** Please consider updating your I2C driver now. **
2226 These enable legacy I2C serial bus commands. Defining
2227 CONFIG_HARD_I2C will include the appropriate I2C driver
2228 for the selected CPU.
2230 This will allow you to use i2c commands at the u-boot
2231 command line (as long as you set CONFIG_CMD_I2C in
2232 CONFIG_COMMANDS) and communicate with i2c based realtime
2233 clock chips. See common/cmd_i2c.c for a description of the
2234 command line interface.
2236 CONFIG_HARD_I2C selects a hardware I2C controller.
2238 There are several other quantities that must also be
2239 defined when you define CONFIG_HARD_I2C.
2241 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2242 to be the frequency (in Hz) at which you wish your i2c bus
2243 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2244 the CPU's i2c node address).
2246 Now, the u-boot i2c code for the mpc8xx
2247 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2248 and so its address should therefore be cleared to 0 (See,
2249 eg, MPC823e User's Manual p.16-473). So, set
2250 CONFIG_SYS_I2C_SLAVE to 0.
2252 CONFIG_SYS_I2C_INIT_MPC5XXX
2254 When a board is reset during an i2c bus transfer
2255 chips might think that the current transfer is still
2256 in progress. Reset the slave devices by sending start
2257 commands until the slave device responds.
2259 That's all that's required for CONFIG_HARD_I2C.
2261 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2262 then the following macros need to be defined (examples are
2263 from include/configs/lwmon.h):
2267 (Optional). Any commands necessary to enable the I2C
2268 controller or configure ports.
2270 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2274 (Only for MPC8260 CPU). The I/O port to use (the code
2275 assumes both bits are on the same port). Valid values
2276 are 0..3 for ports A..D.
2280 The code necessary to make the I2C data line active
2281 (driven). If the data line is open collector, this
2284 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2288 The code necessary to make the I2C data line tri-stated
2289 (inactive). If the data line is open collector, this
2292 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2296 Code that returns true if the I2C data line is high,
2299 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2303 If <bit> is true, sets the I2C data line high. If it
2304 is false, it clears it (low).
2306 eg: #define I2C_SDA(bit) \
2307 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2308 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2312 If <bit> is true, sets the I2C clock line high. If it
2313 is false, it clears it (low).
2315 eg: #define I2C_SCL(bit) \
2316 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2317 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2321 This delay is invoked four times per clock cycle so this
2322 controls the rate of data transfer. The data rate thus
2323 is 1 / (I2C_DELAY * 4). Often defined to be something
2326 #define I2C_DELAY udelay(2)
2328 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2330 If your arch supports the generic GPIO framework (asm/gpio.h),
2331 then you may alternatively define the two GPIOs that are to be
2332 used as SCL / SDA. Any of the previous I2C_xxx macros will
2333 have GPIO-based defaults assigned to them as appropriate.
2335 You should define these to the GPIO value as given directly to
2336 the generic GPIO functions.
2338 CONFIG_SYS_I2C_INIT_BOARD
2340 When a board is reset during an i2c bus transfer
2341 chips might think that the current transfer is still
2342 in progress. On some boards it is possible to access
2343 the i2c SCLK line directly, either by using the
2344 processor pin as a GPIO or by having a second pin
2345 connected to the bus. If this option is defined a
2346 custom i2c_init_board() routine in boards/xxx/board.c
2347 is run early in the boot sequence.
2349 CONFIG_SYS_I2C_BOARD_LATE_INIT
2351 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2352 defined a custom i2c_board_late_init() routine in
2353 boards/xxx/board.c is run AFTER the operations in i2c_init()
2354 is completed. This callpoint can be used to unreset i2c bus
2355 using CPU i2c controller register accesses for CPUs whose i2c
2356 controller provide such a method. It is called at the end of
2357 i2c_init() to allow i2c_init operations to setup the i2c bus
2358 controller on the CPU (e.g. setting bus speed & slave address).
2360 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2362 This option enables configuration of bi_iic_fast[] flags
2363 in u-boot bd_info structure based on u-boot environment
2364 variable "i2cfast". (see also i2cfast)
2366 CONFIG_I2C_MULTI_BUS
2368 This option allows the use of multiple I2C buses, each of which
2369 must have a controller. At any point in time, only one bus is
2370 active. To switch to a different bus, use the 'i2c dev' command.
2371 Note that bus numbering is zero-based.
2373 CONFIG_SYS_I2C_NOPROBES
2375 This option specifies a list of I2C devices that will be skipped
2376 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2377 is set, specify a list of bus-device pairs. Otherwise, specify
2378 a 1D array of device addresses
2381 #undef CONFIG_I2C_MULTI_BUS
2382 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2384 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2386 #define CONFIG_I2C_MULTI_BUS
2387 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2389 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2391 CONFIG_SYS_SPD_BUS_NUM
2393 If defined, then this indicates the I2C bus number for DDR SPD.
2394 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2396 CONFIG_SYS_RTC_BUS_NUM
2398 If defined, then this indicates the I2C bus number for the RTC.
2399 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2401 CONFIG_SYS_DTT_BUS_NUM
2403 If defined, then this indicates the I2C bus number for the DTT.
2404 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2406 CONFIG_SYS_I2C_DTT_ADDR:
2408 If defined, specifies the I2C address of the DTT device.
2409 If not defined, then U-Boot uses predefined value for
2410 specified DTT device.
2412 CONFIG_SOFT_I2C_READ_REPEATED_START
2414 defining this will force the i2c_read() function in
2415 the soft_i2c driver to perform an I2C repeated start
2416 between writing the address pointer and reading the
2417 data. If this define is omitted the default behaviour
2418 of doing a stop-start sequence will be used. Most I2C
2419 devices can use either method, but some require one or
2422 - SPI Support: CONFIG_SPI
2424 Enables SPI driver (so far only tested with
2425 SPI EEPROM, also an instance works with Crystal A/D and
2426 D/As on the SACSng board)
2430 Enables the driver for SPI controller on SuperH. Currently
2431 only SH7757 is supported.
2435 Enables a software (bit-bang) SPI driver rather than
2436 using hardware support. This is a general purpose
2437 driver that only requires three general I/O port pins
2438 (two outputs, one input) to function. If this is
2439 defined, the board configuration must define several
2440 SPI configuration items (port pins to use, etc). For
2441 an example, see include/configs/sacsng.h.
2445 Enables a hardware SPI driver for general-purpose reads
2446 and writes. As with CONFIG_SOFT_SPI, the board configuration
2447 must define a list of chip-select function pointers.
2448 Currently supported on some MPC8xxx processors. For an
2449 example, see include/configs/mpc8349emds.h.
2453 Enables the driver for the SPI controllers on i.MX and MXC
2454 SoCs. Currently i.MX31/35/51 are supported.
2456 CONFIG_SYS_SPI_MXC_WAIT
2457 Timeout for waiting until spi transfer completed.
2458 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2460 - FPGA Support: CONFIG_FPGA
2462 Enables FPGA subsystem.
2464 CONFIG_FPGA_<vendor>
2466 Enables support for specific chip vendors.
2469 CONFIG_FPGA_<family>
2471 Enables support for FPGA family.
2472 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2476 Specify the number of FPGA devices to support.
2478 CONFIG_CMD_FPGA_LOADMK
2480 Enable support for fpga loadmk command
2482 CONFIG_CMD_FPGA_LOADP
2484 Enable support for fpga loadp command - load partial bitstream
2486 CONFIG_CMD_FPGA_LOADBP
2488 Enable support for fpga loadbp command - load partial bitstream
2491 CONFIG_SYS_FPGA_PROG_FEEDBACK
2493 Enable printing of hash marks during FPGA configuration.
2495 CONFIG_SYS_FPGA_CHECK_BUSY
2497 Enable checks on FPGA configuration interface busy
2498 status by the configuration function. This option
2499 will require a board or device specific function to
2504 If defined, a function that provides delays in the FPGA
2505 configuration driver.
2507 CONFIG_SYS_FPGA_CHECK_CTRLC
2508 Allow Control-C to interrupt FPGA configuration
2510 CONFIG_SYS_FPGA_CHECK_ERROR
2512 Check for configuration errors during FPGA bitfile
2513 loading. For example, abort during Virtex II
2514 configuration if the INIT_B line goes low (which
2515 indicated a CRC error).
2517 CONFIG_SYS_FPGA_WAIT_INIT
2519 Maximum time to wait for the INIT_B line to de-assert
2520 after PROB_B has been de-asserted during a Virtex II
2521 FPGA configuration sequence. The default time is 500
2524 CONFIG_SYS_FPGA_WAIT_BUSY
2526 Maximum time to wait for BUSY to de-assert during
2527 Virtex II FPGA configuration. The default is 5 ms.
2529 CONFIG_SYS_FPGA_WAIT_CONFIG
2531 Time to wait after FPGA configuration. The default is
2534 - Configuration Management:
2537 Some SoCs need special image types (e.g. U-Boot binary
2538 with a special header) as build targets. By defining
2539 CONFIG_BUILD_TARGET in the SoC / board header, this
2540 special image will be automatically built upon calling
2545 If defined, this string will be added to the U-Boot
2546 version information (U_BOOT_VERSION)
2548 - Vendor Parameter Protection:
2550 U-Boot considers the values of the environment
2551 variables "serial#" (Board Serial Number) and
2552 "ethaddr" (Ethernet Address) to be parameters that
2553 are set once by the board vendor / manufacturer, and
2554 protects these variables from casual modification by
2555 the user. Once set, these variables are read-only,
2556 and write or delete attempts are rejected. You can
2557 change this behaviour:
2559 If CONFIG_ENV_OVERWRITE is #defined in your config
2560 file, the write protection for vendor parameters is
2561 completely disabled. Anybody can change or delete
2564 Alternatively, if you define _both_ an ethaddr in the
2565 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2566 Ethernet address is installed in the environment,
2567 which can be changed exactly ONCE by the user. [The
2568 serial# is unaffected by this, i. e. it remains
2571 The same can be accomplished in a more flexible way
2572 for any variable by configuring the type of access
2573 to allow for those variables in the ".flags" variable
2574 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2579 Define this variable to enable the reservation of
2580 "protected RAM", i. e. RAM which is not overwritten
2581 by U-Boot. Define CONFIG_PRAM to hold the number of
2582 kB you want to reserve for pRAM. You can overwrite
2583 this default value by defining an environment
2584 variable "pram" to the number of kB you want to
2585 reserve. Note that the board info structure will
2586 still show the full amount of RAM. If pRAM is
2587 reserved, a new environment variable "mem" will
2588 automatically be defined to hold the amount of
2589 remaining RAM in a form that can be passed as boot
2590 argument to Linux, for instance like that:
2592 setenv bootargs ... mem=\${mem}
2595 This way you can tell Linux not to use this memory,
2596 either, which results in a memory region that will
2597 not be affected by reboots.
2599 *WARNING* If your board configuration uses automatic
2600 detection of the RAM size, you must make sure that
2601 this memory test is non-destructive. So far, the
2602 following board configurations are known to be
2605 IVMS8, IVML24, SPD8xx, TQM8xxL,
2606 HERMES, IP860, RPXlite, LWMON,
2609 - Access to physical memory region (> 4GB)
2610 Some basic support is provided for operations on memory not
2611 normally accessible to U-Boot - e.g. some architectures
2612 support access to more than 4GB of memory on 32-bit
2613 machines using physical address extension or similar.
2614 Define CONFIG_PHYSMEM to access this basic support, which
2615 currently only supports clearing the memory.
2620 Define this variable to stop the system in case of a
2621 fatal error, so that you have to reset it manually.
2622 This is probably NOT a good idea for an embedded
2623 system where you want the system to reboot
2624 automatically as fast as possible, but it may be
2625 useful during development since you can try to debug
2626 the conditions that lead to the situation.
2628 CONFIG_NET_RETRY_COUNT
2630 This variable defines the number of retries for
2631 network operations like ARP, RARP, TFTP, or BOOTP
2632 before giving up the operation. If not defined, a
2633 default value of 5 is used.
2637 Timeout waiting for an ARP reply in milliseconds.
2641 Timeout in milliseconds used in NFS protocol.
2642 If you encounter "ERROR: Cannot umount" in nfs command,
2643 try longer timeout such as
2644 #define CONFIG_NFS_TIMEOUT 10000UL
2646 - Command Interpreter:
2647 CONFIG_AUTO_COMPLETE
2649 Enable auto completion of commands using TAB.
2651 CONFIG_SYS_PROMPT_HUSH_PS2
2653 This defines the secondary prompt string, which is
2654 printed when the command interpreter needs more input
2655 to complete a command. Usually "> ".
2659 In the current implementation, the local variables
2660 space and global environment variables space are
2661 separated. Local variables are those you define by
2662 simply typing `name=value'. To access a local
2663 variable later on, you have write `$name' or
2664 `${name}'; to execute the contents of a variable
2665 directly type `$name' at the command prompt.
2667 Global environment variables are those you use
2668 setenv/printenv to work with. To run a command stored
2669 in such a variable, you need to use the run command,
2670 and you must not use the '$' sign to access them.
2672 To store commands and special characters in a
2673 variable, please use double quotation marks
2674 surrounding the whole text of the variable, instead
2675 of the backslashes before semicolons and special
2678 - Command Line Editing and History:
2679 CONFIG_CMDLINE_EDITING
2681 Enable editing and History functions for interactive
2682 command line input operations
2684 - Command Line PS1/PS2 support:
2685 CONFIG_CMDLINE_PS_SUPPORT
2687 Enable support for changing the command prompt string
2688 at run-time. Only static string is supported so far.
2689 The string is obtained from environment variables PS1
2692 - Default Environment:
2693 CONFIG_EXTRA_ENV_SETTINGS
2695 Define this to contain any number of null terminated
2696 strings (variable = value pairs) that will be part of
2697 the default environment compiled into the boot image.
2699 For example, place something like this in your
2700 board's config file:
2702 #define CONFIG_EXTRA_ENV_SETTINGS \
2706 Warning: This method is based on knowledge about the
2707 internal format how the environment is stored by the
2708 U-Boot code. This is NOT an official, exported
2709 interface! Although it is unlikely that this format
2710 will change soon, there is no guarantee either.
2711 You better know what you are doing here.
2713 Note: overly (ab)use of the default environment is
2714 discouraged. Make sure to check other ways to preset
2715 the environment like the "source" command or the
2718 CONFIG_ENV_VARS_UBOOT_CONFIG
2720 Define this in order to add variables describing the
2721 U-Boot build configuration to the default environment.
2722 These will be named arch, cpu, board, vendor, and soc.
2724 Enabling this option will cause the following to be defined:
2732 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2734 Define this in order to add variables describing certain
2735 run-time determined information about the hardware to the
2736 environment. These will be named board_name, board_rev.
2738 CONFIG_DELAY_ENVIRONMENT
2740 Normally the environment is loaded when the board is
2741 initialised so that it is available to U-Boot. This inhibits
2742 that so that the environment is not available until
2743 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2744 this is instead controlled by the value of
2745 /config/load-environment.
2747 - DataFlash Support:
2748 CONFIG_HAS_DATAFLASH
2750 Defining this option enables DataFlash features and
2751 allows to read/write in Dataflash via the standard
2754 - Serial Flash support
2757 Defining this option enables SPI flash commands
2758 'sf probe/read/write/erase/update'.
2760 Usage requires an initial 'probe' to define the serial
2761 flash parameters, followed by read/write/erase/update
2764 The following defaults may be provided by the platform
2765 to handle the common case when only a single serial
2766 flash is present on the system.
2768 CONFIG_SF_DEFAULT_BUS Bus identifier
2769 CONFIG_SF_DEFAULT_CS Chip-select
2770 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2771 CONFIG_SF_DEFAULT_SPEED in Hz
2775 Define this option to include a destructive SPI flash
2778 CONFIG_SF_DUAL_FLASH Dual flash memories
2780 Define this option to use dual flash support where two flash
2781 memories can be connected with a given cs line.
2782 Currently Xilinx Zynq qspi supports these type of connections.
2784 - SystemACE Support:
2787 Adding this option adds support for Xilinx SystemACE
2788 chips attached via some sort of local bus. The address
2789 of the chip must also be defined in the
2790 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2792 #define CONFIG_SYSTEMACE
2793 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2795 When SystemACE support is added, the "ace" device type
2796 becomes available to the fat commands, i.e. fatls.
2798 - TFTP Fixed UDP Port:
2801 If this is defined, the environment variable tftpsrcp
2802 is used to supply the TFTP UDP source port value.
2803 If tftpsrcp isn't defined, the normal pseudo-random port
2804 number generator is used.
2806 Also, the environment variable tftpdstp is used to supply
2807 the TFTP UDP destination port value. If tftpdstp isn't
2808 defined, the normal port 69 is used.
2810 The purpose for tftpsrcp is to allow a TFTP server to
2811 blindly start the TFTP transfer using the pre-configured
2812 target IP address and UDP port. This has the effect of
2813 "punching through" the (Windows XP) firewall, allowing
2814 the remainder of the TFTP transfer to proceed normally.
2815 A better solution is to properly configure the firewall,
2816 but sometimes that is not allowed.
2821 This enables a generic 'hash' command which can produce
2822 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2826 Enable the hash verify command (hash -v). This adds to code
2829 CONFIG_SHA1 - This option enables support of hashing using SHA1
2830 algorithm. The hash is calculated in software.
2831 CONFIG_SHA256 - This option enables support of hashing using
2832 SHA256 algorithm. The hash is calculated in software.
2833 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2834 for SHA1/SHA256 hashing.
2835 This affects the 'hash' command and also the
2836 hash_lookup_algo() function.
2837 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2838 hardware-acceleration for SHA1/SHA256 progressive hashing.
2839 Data can be streamed in a block at a time and the hashing
2840 is performed in hardware.
2842 Note: There is also a sha1sum command, which should perhaps
2843 be deprecated in favour of 'hash sha1'.
2845 - Freescale i.MX specific commands:
2846 CONFIG_CMD_HDMIDETECT
2847 This enables 'hdmidet' command which returns true if an
2848 HDMI monitor is detected. This command is i.MX 6 specific.
2850 - bootcount support:
2851 CONFIG_BOOTCOUNT_LIMIT
2853 This enables the bootcounter support, see:
2854 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2857 enable special bootcounter support on at91sam9xe based boards.
2859 enable special bootcounter support on da850 based boards.
2860 CONFIG_BOOTCOUNT_RAM
2861 enable support for the bootcounter in RAM
2862 CONFIG_BOOTCOUNT_I2C
2863 enable support for the bootcounter on an i2c (like RTC) device.
2864 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2865 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2867 CONFIG_BOOTCOUNT_ALEN = address len
2869 - Show boot progress:
2870 CONFIG_SHOW_BOOT_PROGRESS
2872 Defining this option allows to add some board-
2873 specific code (calling a user-provided function
2874 "show_boot_progress(int)") that enables you to show
2875 the system's boot progress on some display (for
2876 example, some LED's) on your board. At the moment,
2877 the following checkpoints are implemented:
2880 Legacy uImage format:
2883 1 common/cmd_bootm.c before attempting to boot an image
2884 -1 common/cmd_bootm.c Image header has bad magic number
2885 2 common/cmd_bootm.c Image header has correct magic number
2886 -2 common/cmd_bootm.c Image header has bad checksum
2887 3 common/cmd_bootm.c Image header has correct checksum
2888 -3 common/cmd_bootm.c Image data has bad checksum
2889 4 common/cmd_bootm.c Image data has correct checksum
2890 -4 common/cmd_bootm.c Image is for unsupported architecture
2891 5 common/cmd_bootm.c Architecture check OK
2892 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2893 6 common/cmd_bootm.c Image Type check OK
2894 -6 common/cmd_bootm.c gunzip uncompression error
2895 -7 common/cmd_bootm.c Unimplemented compression type
2896 7 common/cmd_bootm.c Uncompression OK
2897 8 common/cmd_bootm.c No uncompress/copy overwrite error
2898 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2900 9 common/image.c Start initial ramdisk verification
2901 -10 common/image.c Ramdisk header has bad magic number
2902 -11 common/image.c Ramdisk header has bad checksum
2903 10 common/image.c Ramdisk header is OK
2904 -12 common/image.c Ramdisk data has bad checksum
2905 11 common/image.c Ramdisk data has correct checksum
2906 12 common/image.c Ramdisk verification complete, start loading
2907 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2908 13 common/image.c Start multifile image verification
2909 14 common/image.c No initial ramdisk, no multifile, continue.
2911 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2913 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2914 -31 post/post.c POST test failed, detected by post_output_backlog()
2915 -32 post/post.c POST test failed, detected by post_run_single()
2917 34 common/cmd_doc.c before loading a Image from a DOC device
2918 -35 common/cmd_doc.c Bad usage of "doc" command
2919 35 common/cmd_doc.c correct usage of "doc" command
2920 -36 common/cmd_doc.c No boot device
2921 36 common/cmd_doc.c correct boot device
2922 -37 common/cmd_doc.c Unknown Chip ID on boot device
2923 37 common/cmd_doc.c correct chip ID found, device available
2924 -38 common/cmd_doc.c Read Error on boot device
2925 38 common/cmd_doc.c reading Image header from DOC device OK
2926 -39 common/cmd_doc.c Image header has bad magic number
2927 39 common/cmd_doc.c Image header has correct magic number
2928 -40 common/cmd_doc.c Error reading Image from DOC device
2929 40 common/cmd_doc.c Image header has correct magic number
2930 41 common/cmd_ide.c before loading a Image from a IDE device
2931 -42 common/cmd_ide.c Bad usage of "ide" command
2932 42 common/cmd_ide.c correct usage of "ide" command
2933 -43 common/cmd_ide.c No boot device
2934 43 common/cmd_ide.c boot device found
2935 -44 common/cmd_ide.c Device not available
2936 44 common/cmd_ide.c Device available
2937 -45 common/cmd_ide.c wrong partition selected
2938 45 common/cmd_ide.c partition selected
2939 -46 common/cmd_ide.c Unknown partition table
2940 46 common/cmd_ide.c valid partition table found
2941 -47 common/cmd_ide.c Invalid partition type
2942 47 common/cmd_ide.c correct partition type
2943 -48 common/cmd_ide.c Error reading Image Header on boot device
2944 48 common/cmd_ide.c reading Image Header from IDE device OK
2945 -49 common/cmd_ide.c Image header has bad magic number
2946 49 common/cmd_ide.c Image header has correct magic number
2947 -50 common/cmd_ide.c Image header has bad checksum
2948 50 common/cmd_ide.c Image header has correct checksum
2949 -51 common/cmd_ide.c Error reading Image from IDE device
2950 51 common/cmd_ide.c reading Image from IDE device OK
2951 52 common/cmd_nand.c before loading a Image from a NAND device
2952 -53 common/cmd_nand.c Bad usage of "nand" command
2953 53 common/cmd_nand.c correct usage of "nand" command
2954 -54 common/cmd_nand.c No boot device
2955 54 common/cmd_nand.c boot device found
2956 -55 common/cmd_nand.c Unknown Chip ID on boot device
2957 55 common/cmd_nand.c correct chip ID found, device available
2958 -56 common/cmd_nand.c Error reading Image Header on boot device
2959 56 common/cmd_nand.c reading Image Header from NAND device OK
2960 -57 common/cmd_nand.c Image header has bad magic number
2961 57 common/cmd_nand.c Image header has correct magic number
2962 -58 common/cmd_nand.c Error reading Image from NAND device
2963 58 common/cmd_nand.c reading Image from NAND device OK
2965 -60 common/env_common.c Environment has a bad CRC, using default
2967 64 net/eth.c starting with Ethernet configuration.
2968 -64 net/eth.c no Ethernet found.
2969 65 net/eth.c Ethernet found.
2971 -80 common/cmd_net.c usage wrong
2972 80 common/cmd_net.c before calling net_loop()
2973 -81 common/cmd_net.c some error in net_loop() occurred
2974 81 common/cmd_net.c net_loop() back without error
2975 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2976 82 common/cmd_net.c trying automatic boot
2977 83 common/cmd_net.c running "source" command
2978 -83 common/cmd_net.c some error in automatic boot or "source" command
2979 84 common/cmd_net.c end without errors
2984 100 common/cmd_bootm.c Kernel FIT Image has correct format
2985 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2986 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2987 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2988 102 common/cmd_bootm.c Kernel unit name specified
2989 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2990 103 common/cmd_bootm.c Found configuration node
2991 104 common/cmd_bootm.c Got kernel subimage node offset
2992 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2993 105 common/cmd_bootm.c Kernel subimage hash verification OK
2994 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2995 106 common/cmd_bootm.c Architecture check OK
2996 -106 common/cmd_bootm.c Kernel subimage has wrong type
2997 107 common/cmd_bootm.c Kernel subimage type OK
2998 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2999 108 common/cmd_bootm.c Got kernel subimage data/size
3000 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3001 -109 common/cmd_bootm.c Can't get kernel subimage type
3002 -110 common/cmd_bootm.c Can't get kernel subimage comp
3003 -111 common/cmd_bootm.c Can't get kernel subimage os
3004 -112 common/cmd_bootm.c Can't get kernel subimage load address
3005 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3007 120 common/image.c Start initial ramdisk verification
3008 -120 common/image.c Ramdisk FIT image has incorrect format
3009 121 common/image.c Ramdisk FIT image has correct format
3010 122 common/image.c No ramdisk subimage unit name, using configuration
3011 -122 common/image.c Can't get configuration for ramdisk subimage
3012 123 common/image.c Ramdisk unit name specified
3013 -124 common/image.c Can't get ramdisk subimage node offset
3014 125 common/image.c Got ramdisk subimage node offset
3015 -125 common/image.c Ramdisk subimage hash verification failed
3016 126 common/image.c Ramdisk subimage hash verification OK
3017 -126 common/image.c Ramdisk subimage for unsupported architecture
3018 127 common/image.c Architecture check OK
3019 -127 common/image.c Can't get ramdisk subimage data/size
3020 128 common/image.c Got ramdisk subimage data/size
3021 129 common/image.c Can't get ramdisk load address
3022 -129 common/image.c Got ramdisk load address
3024 -130 common/cmd_doc.c Incorrect FIT image format
3025 131 common/cmd_doc.c FIT image format OK
3027 -140 common/cmd_ide.c Incorrect FIT image format
3028 141 common/cmd_ide.c FIT image format OK
3030 -150 common/cmd_nand.c Incorrect FIT image format
3031 151 common/cmd_nand.c FIT image format OK
3033 - legacy image format:
3034 CONFIG_IMAGE_FORMAT_LEGACY
3035 enables the legacy image format support in U-Boot.
3038 enabled if CONFIG_FIT_SIGNATURE is not defined.
3040 CONFIG_DISABLE_IMAGE_LEGACY
3041 disable the legacy image format
3043 This define is introduced, as the legacy image format is
3044 enabled per default for backward compatibility.
3046 - FIT image support:
3047 CONFIG_FIT_DISABLE_SHA256
3048 Supporting SHA256 hashes has quite an impact on binary size.
3049 For constrained systems sha256 hash support can be disabled
3052 TODO(sjg@chromium.org): Adjust this option to be positive,
3053 and move it to Kconfig
3055 - Standalone program support:
3056 CONFIG_STANDALONE_LOAD_ADDR
3058 This option defines a board specific value for the
3059 address where standalone program gets loaded, thus
3060 overwriting the architecture dependent default
3063 - Frame Buffer Address:
3066 Define CONFIG_FB_ADDR if you want to use specific
3067 address for frame buffer. This is typically the case
3068 when using a graphics controller has separate video
3069 memory. U-Boot will then place the frame buffer at
3070 the given address instead of dynamically reserving it
3071 in system RAM by calling lcd_setmem(), which grabs
3072 the memory for the frame buffer depending on the
3073 configured panel size.
3075 Please see board_init_f function.
3077 - Automatic software updates via TFTP server
3079 CONFIG_UPDATE_TFTP_CNT_MAX
3080 CONFIG_UPDATE_TFTP_MSEC_MAX
3082 These options enable and control the auto-update feature;
3083 for a more detailed description refer to doc/README.update.
3085 - MTD Support (mtdparts command, UBI support)
3088 Adds the MTD device infrastructure from the Linux kernel.
3089 Needed for mtdparts command support.
3091 CONFIG_MTD_PARTITIONS
3093 Adds the MTD partitioning infrastructure from the Linux
3094 kernel. Needed for UBI support.
3099 Adds commands for interacting with MTD partitions formatted
3100 with the UBI flash translation layer
3102 Requires also defining CONFIG_RBTREE
3104 CONFIG_UBI_SILENCE_MSG
3106 Make the verbose messages from UBI stop printing. This leaves
3107 warnings and errors enabled.
3110 CONFIG_MTD_UBI_WL_THRESHOLD
3111 This parameter defines the maximum difference between the highest
3112 erase counter value and the lowest erase counter value of eraseblocks
3113 of UBI devices. When this threshold is exceeded, UBI starts performing
3114 wear leveling by means of moving data from eraseblock with low erase
3115 counter to eraseblocks with high erase counter.
3117 The default value should be OK for SLC NAND flashes, NOR flashes and
3118 other flashes which have eraseblock life-cycle 100000 or more.
3119 However, in case of MLC NAND flashes which typically have eraseblock
3120 life-cycle less than 10000, the threshold should be lessened (e.g.,
3121 to 128 or 256, although it does not have to be power of 2).
3125 CONFIG_MTD_UBI_BEB_LIMIT
3126 This option specifies the maximum bad physical eraseblocks UBI
3127 expects on the MTD device (per 1024 eraseblocks). If the
3128 underlying flash does not admit of bad eraseblocks (e.g. NOR
3129 flash), this value is ignored.
3131 NAND datasheets often specify the minimum and maximum NVM
3132 (Number of Valid Blocks) for the flashes' endurance lifetime.
3133 The maximum expected bad eraseblocks per 1024 eraseblocks
3134 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3135 which gives 20 for most NANDs (MaxNVB is basically the total
3136 count of eraseblocks on the chip).
3138 To put it differently, if this value is 20, UBI will try to
3139 reserve about 1.9% of physical eraseblocks for bad blocks
3140 handling. And that will be 1.9% of eraseblocks on the entire
3141 NAND chip, not just the MTD partition UBI attaches. This means
3142 that if you have, say, a NAND flash chip admits maximum 40 bad
3143 eraseblocks, and it is split on two MTD partitions of the same
3144 size, UBI will reserve 40 eraseblocks when attaching a
3149 CONFIG_MTD_UBI_FASTMAP
3150 Fastmap is a mechanism which allows attaching an UBI device
3151 in nearly constant time. Instead of scanning the whole MTD device it
3152 only has to locate a checkpoint (called fastmap) on the device.
3153 The on-flash fastmap contains all information needed to attach
3154 the device. Using fastmap makes only sense on large devices where
3155 attaching by scanning takes long. UBI will not automatically install
3156 a fastmap on old images, but you can set the UBI parameter
3157 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3158 that fastmap-enabled images are still usable with UBI implementations
3159 without fastmap support. On typical flash devices the whole fastmap
3160 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3162 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3163 Set this parameter to enable fastmap automatically on images
3167 CONFIG_MTD_UBI_FM_DEBUG
3168 Enable UBI fastmap debug
3174 Adds commands for interacting with UBI volumes formatted as
3175 UBIFS. UBIFS is read-only in u-boot.
3177 Requires UBI support as well as CONFIG_LZO
3179 CONFIG_UBIFS_SILENCE_MSG
3181 Make the verbose messages from UBIFS stop printing. This leaves
3182 warnings and errors enabled.
3186 Enable building of SPL globally.
3189 LDSCRIPT for linking the SPL binary.
3191 CONFIG_SPL_MAX_FOOTPRINT
3192 Maximum size in memory allocated to the SPL, BSS included.
3193 When defined, the linker checks that the actual memory
3194 used by SPL from _start to __bss_end does not exceed it.
3195 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3196 must not be both defined at the same time.
3199 Maximum size of the SPL image (text, data, rodata, and
3200 linker lists sections), BSS excluded.
3201 When defined, the linker checks that the actual size does
3204 CONFIG_SPL_TEXT_BASE
3205 TEXT_BASE for linking the SPL binary.
3207 CONFIG_SPL_RELOC_TEXT_BASE
3208 Address to relocate to. If unspecified, this is equal to
3209 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3211 CONFIG_SPL_BSS_START_ADDR
3212 Link address for the BSS within the SPL binary.
3214 CONFIG_SPL_BSS_MAX_SIZE
3215 Maximum size in memory allocated to the SPL BSS.
3216 When defined, the linker checks that the actual memory used
3217 by SPL from __bss_start to __bss_end does not exceed it.
3218 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3219 must not be both defined at the same time.
3222 Adress of the start of the stack SPL will use
3224 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3225 When defined, SPL will panic() if the image it has
3226 loaded does not have a signature.
3227 Defining this is useful when code which loads images
3228 in SPL cannot guarantee that absolutely all read errors
3230 An example is the LPC32XX MLC NAND driver, which will
3231 consider that a completely unreadable NAND block is bad,
3232 and thus should be skipped silently.
3234 CONFIG_SPL_RELOC_STACK
3235 Adress of the start of the stack SPL will use after
3236 relocation. If unspecified, this is equal to
3239 CONFIG_SYS_SPL_MALLOC_START
3240 Starting address of the malloc pool used in SPL.
3241 When this option is set the full malloc is used in SPL and
3242 it is set up by spl_init() and before that, the simple malloc()
3243 can be used if CONFIG_SYS_MALLOC_F is defined.
3245 CONFIG_SYS_SPL_MALLOC_SIZE
3246 The size of the malloc pool used in SPL.
3248 CONFIG_SPL_FRAMEWORK
3249 Enable the SPL framework under common/. This framework
3250 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3251 NAND loading of the Linux Kernel.
3254 Enable booting directly to an OS from SPL.
3255 See also: doc/README.falcon
3257 CONFIG_SPL_DISPLAY_PRINT
3258 For ARM, enable an optional function to print more information
3259 about the running system.
3261 CONFIG_SPL_INIT_MINIMAL
3262 Arch init code should be built for a very small image
3264 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3265 Partition on the MMC to load U-Boot from when the MMC is being
3268 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3269 Sector to load kernel uImage from when MMC is being
3270 used in raw mode (for Falcon mode)
3272 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3273 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3274 Sector and number of sectors to load kernel argument
3275 parameters from when MMC is being used in raw mode
3278 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3279 Partition on the MMC to load U-Boot from when the MMC is being
3282 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3283 Filename to read to load U-Boot when reading from filesystem
3285 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3286 Filename to read to load kernel uImage when reading
3287 from filesystem (for Falcon mode)
3289 CONFIG_SPL_FS_LOAD_ARGS_NAME
3290 Filename to read to load kernel argument parameters
3291 when reading from filesystem (for Falcon mode)
3293 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3294 Set this for NAND SPL on PPC mpc83xx targets, so that
3295 start.S waits for the rest of the SPL to load before
3296 continuing (the hardware starts execution after just
3297 loading the first page rather than the full 4K).
3299 CONFIG_SPL_SKIP_RELOCATE
3300 Avoid SPL relocation
3302 CONFIG_SPL_NAND_BASE
3303 Include nand_base.c in the SPL. Requires
3304 CONFIG_SPL_NAND_DRIVERS.
3306 CONFIG_SPL_NAND_DRIVERS
3307 SPL uses normal NAND drivers, not minimal drivers.
3310 Include standard software ECC in the SPL
3312 CONFIG_SPL_NAND_SIMPLE
3313 Support for NAND boot using simple NAND drivers that
3314 expose the cmd_ctrl() interface.
3317 Support for a lightweight UBI (fastmap) scanner and
3320 CONFIG_SPL_NAND_RAW_ONLY
3321 Support to boot only raw u-boot.bin images. Use this only
3322 if you need to save space.
3324 CONFIG_SPL_COMMON_INIT_DDR
3325 Set for common ddr init with serial presence detect in
3328 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3329 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3330 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3331 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3332 CONFIG_SYS_NAND_ECCBYTES
3333 Defines the size and behavior of the NAND that SPL uses
3336 CONFIG_SPL_NAND_BOOT
3337 Add support NAND boot
3339 CONFIG_SYS_NAND_U_BOOT_OFFS
3340 Location in NAND to read U-Boot from
3342 CONFIG_SYS_NAND_U_BOOT_DST
3343 Location in memory to load U-Boot to
3345 CONFIG_SYS_NAND_U_BOOT_SIZE
3346 Size of image to load
3348 CONFIG_SYS_NAND_U_BOOT_START
3349 Entry point in loaded image to jump to
3351 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3352 Define this if you need to first read the OOB and then the
3353 data. This is used, for example, on davinci platforms.
3355 CONFIG_SPL_OMAP3_ID_NAND
3356 Support for an OMAP3-specific set of functions to return the
3357 ID and MFR of the first attached NAND chip, if present.
3359 CONFIG_SPL_RAM_DEVICE
3360 Support for running image already present in ram, in SPL binary
3363 Image offset to which the SPL should be padded before appending
3364 the SPL payload. By default, this is defined as
3365 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3366 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3367 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3370 Final target image containing SPL and payload. Some SPLs
3371 use an arch-specific makefile fragment instead, for
3372 example if more than one image needs to be produced.
3374 CONFIG_FIT_SPL_PRINT
3375 Printing information about a FIT image adds quite a bit of
3376 code to SPL. So this is normally disabled in SPL. Use this
3377 option to re-enable it. This will affect the output of the
3378 bootm command when booting a FIT image.
3382 Enable building of TPL globally.
3385 Image offset to which the TPL should be padded before appending
3386 the TPL payload. By default, this is defined as
3387 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3388 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3389 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3391 - Interrupt support (PPC):
3393 There are common interrupt_init() and timer_interrupt()
3394 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3395 for CPU specific initialization. interrupt_init_cpu()
3396 should set decrementer_count to appropriate value. If
3397 CPU resets decrementer automatically after interrupt
3398 (ppc4xx) it should set decrementer_count to zero.
3399 timer_interrupt() calls timer_interrupt_cpu() for CPU
3400 specific handling. If board has watchdog / status_led
3401 / other_activity_monitor it works automatically from
3402 general timer_interrupt().
3405 Board initialization settings:
3406 ------------------------------
3408 During Initialization u-boot calls a number of board specific functions
3409 to allow the preparation of board specific prerequisites, e.g. pin setup
3410 before drivers are initialized. To enable these callbacks the
3411 following configuration macros have to be defined. Currently this is
3412 architecture specific, so please check arch/your_architecture/lib/board.c
3413 typically in board_init_f() and board_init_r().
3415 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3416 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3417 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3418 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3420 Configuration Settings:
3421 -----------------------
3423 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3424 Optionally it can be defined to support 64-bit memory commands.
3426 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3427 undefine this when you're short of memory.
3429 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3430 width of the commands listed in the 'help' command output.
3432 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3433 prompt for user input.
3435 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3437 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3439 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3441 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3442 the application (usually a Linux kernel) when it is
3445 - CONFIG_SYS_BAUDRATE_TABLE:
3446 List of legal baudrate settings for this board.
3448 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3449 Begin and End addresses of the area used by the
3452 - CONFIG_SYS_ALT_MEMTEST:
3453 Enable an alternate, more extensive memory test.
3455 - CONFIG_SYS_MEMTEST_SCRATCH:
3456 Scratch address used by the alternate memory test
3457 You only need to set this if address zero isn't writeable
3459 - CONFIG_SYS_MEM_RESERVE_SECURE
3460 Only implemented for ARMv8 for now.
3461 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3462 is substracted from total RAM and won't be reported to OS.
3463 This memory can be used as secure memory. A variable
3464 gd->arch.secure_ram is used to track the location. In systems
3465 the RAM base is not zero, or RAM is divided into banks,
3466 this variable needs to be recalcuated to get the address.
3468 - CONFIG_SYS_MEM_TOP_HIDE:
3469 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3470 this specified memory area will get subtracted from the top
3471 (end) of RAM and won't get "touched" at all by U-Boot. By
3472 fixing up gd->ram_size the Linux kernel should gets passed
3473 the now "corrected" memory size and won't touch it either.
3474 This should work for arch/ppc and arch/powerpc. Only Linux
3475 board ports in arch/powerpc with bootwrapper support that
3476 recalculate the memory size from the SDRAM controller setup
3477 will have to get fixed in Linux additionally.
3479 This option can be used as a workaround for the 440EPx/GRx
3480 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3483 WARNING: Please make sure that this value is a multiple of
3484 the Linux page size (normally 4k). If this is not the case,
3485 then the end address of the Linux memory will be located at a
3486 non page size aligned address and this could cause major
3489 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3490 Enable temporary baudrate change while serial download
3492 - CONFIG_SYS_SDRAM_BASE:
3493 Physical start address of SDRAM. _Must_ be 0 here.
3495 - CONFIG_SYS_FLASH_BASE:
3496 Physical start address of Flash memory.
3498 - CONFIG_SYS_MONITOR_BASE:
3499 Physical start address of boot monitor code (set by
3500 make config files to be same as the text base address
3501 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3502 CONFIG_SYS_FLASH_BASE when booting from flash.
3504 - CONFIG_SYS_MONITOR_LEN:
3505 Size of memory reserved for monitor code, used to
3506 determine _at_compile_time_ (!) if the environment is
3507 embedded within the U-Boot image, or in a separate
3510 - CONFIG_SYS_MALLOC_LEN:
3511 Size of DRAM reserved for malloc() use.
3513 - CONFIG_SYS_MALLOC_F_LEN
3514 Size of the malloc() pool for use before relocation. If
3515 this is defined, then a very simple malloc() implementation
3516 will become available before relocation. The address is just
3517 below the global data, and the stack is moved down to make
3520 This feature allocates regions with increasing addresses
3521 within the region. calloc() is supported, but realloc()
3522 is not available. free() is supported but does nothing.
3523 The memory will be freed (or in fact just forgotten) when
3524 U-Boot relocates itself.
3526 - CONFIG_SYS_MALLOC_SIMPLE
3527 Provides a simple and small malloc() and calloc() for those
3528 boards which do not use the full malloc in SPL (which is
3529 enabled with CONFIG_SYS_SPL_MALLOC_START).
3531 - CONFIG_SYS_NONCACHED_MEMORY:
3532 Size of non-cached memory area. This area of memory will be
3533 typically located right below the malloc() area and mapped
3534 uncached in the MMU. This is useful for drivers that would
3535 otherwise require a lot of explicit cache maintenance. For
3536 some drivers it's also impossible to properly maintain the
3537 cache. For example if the regions that need to be flushed
3538 are not a multiple of the cache-line size, *and* padding
3539 cannot be allocated between the regions to align them (i.e.
3540 if the HW requires a contiguous array of regions, and the
3541 size of each region is not cache-aligned), then a flush of
3542 one region may result in overwriting data that hardware has
3543 written to another region in the same cache-line. This can
3544 happen for example in network drivers where descriptors for
3545 buffers are typically smaller than the CPU cache-line (e.g.
3546 16 bytes vs. 32 or 64 bytes).
3548 Non-cached memory is only supported on 32-bit ARM at present.
3550 - CONFIG_SYS_BOOTM_LEN:
3551 Normally compressed uImages are limited to an
3552 uncompressed size of 8 MBytes. If this is not enough,
3553 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3554 to adjust this setting to your needs.
3556 - CONFIG_SYS_BOOTMAPSZ:
3557 Maximum size of memory mapped by the startup code of
3558 the Linux kernel; all data that must be processed by
3559 the Linux kernel (bd_info, boot arguments, FDT blob if
3560 used) must be put below this limit, unless "bootm_low"
3561 environment variable is defined and non-zero. In such case
3562 all data for the Linux kernel must be between "bootm_low"
3563 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3564 variable "bootm_mapsize" will override the value of
3565 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3566 then the value in "bootm_size" will be used instead.
3568 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3569 Enable initrd_high functionality. If defined then the
3570 initrd_high feature is enabled and the bootm ramdisk subcommand
3573 - CONFIG_SYS_BOOT_GET_CMDLINE:
3574 Enables allocating and saving kernel cmdline in space between
3575 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3577 - CONFIG_SYS_BOOT_GET_KBD:
3578 Enables allocating and saving a kernel copy of the bd_info in
3579 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3581 - CONFIG_SYS_MAX_FLASH_BANKS:
3582 Max number of Flash memory banks
3584 - CONFIG_SYS_MAX_FLASH_SECT:
3585 Max number of sectors on a Flash chip
3587 - CONFIG_SYS_FLASH_ERASE_TOUT:
3588 Timeout for Flash erase operations (in ms)
3590 - CONFIG_SYS_FLASH_WRITE_TOUT:
3591 Timeout for Flash write operations (in ms)
3593 - CONFIG_SYS_FLASH_LOCK_TOUT
3594 Timeout for Flash set sector lock bit operation (in ms)
3596 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3597 Timeout for Flash clear lock bits operation (in ms)
3599 - CONFIG_SYS_FLASH_PROTECTION
3600 If defined, hardware flash sectors protection is used
3601 instead of U-Boot software protection.
3603 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3605 Enable TFTP transfers directly to flash memory;
3606 without this option such a download has to be
3607 performed in two steps: (1) download to RAM, and (2)
3608 copy from RAM to flash.
3610 The two-step approach is usually more reliable, since
3611 you can check if the download worked before you erase
3612 the flash, but in some situations (when system RAM is
3613 too limited to allow for a temporary copy of the
3614 downloaded image) this option may be very useful.
3616 - CONFIG_SYS_FLASH_CFI:
3617 Define if the flash driver uses extra elements in the
3618 common flash structure for storing flash geometry.
3620 - CONFIG_FLASH_CFI_DRIVER
3621 This option also enables the building of the cfi_flash driver
3622 in the drivers directory
3624 - CONFIG_FLASH_CFI_MTD
3625 This option enables the building of the cfi_mtd driver
3626 in the drivers directory. The driver exports CFI flash
3629 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3630 Use buffered writes to flash.
3632 - CONFIG_FLASH_SPANSION_S29WS_N
3633 s29ws-n MirrorBit flash has non-standard addresses for buffered
3636 - CONFIG_SYS_FLASH_QUIET_TEST
3637 If this option is defined, the common CFI flash doesn't
3638 print it's warning upon not recognized FLASH banks. This
3639 is useful, if some of the configured banks are only
3640 optionally available.
3642 - CONFIG_FLASH_SHOW_PROGRESS
3643 If defined (must be an integer), print out countdown
3644 digits and dots. Recommended value: 45 (9..1) for 80
3645 column displays, 15 (3..1) for 40 column displays.
3647 - CONFIG_FLASH_VERIFY
3648 If defined, the content of the flash (destination) is compared
3649 against the source after the write operation. An error message
3650 will be printed when the contents are not identical.
3651 Please note that this option is useless in nearly all cases,
3652 since such flash programming errors usually are detected earlier
3653 while unprotecting/erasing/programming. Please only enable
3654 this option if you really know what you are doing.
3656 - CONFIG_SYS_RX_ETH_BUFFER:
3657 Defines the number of Ethernet receive buffers. On some
3658 Ethernet controllers it is recommended to set this value
3659 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3660 buffers can be full shortly after enabling the interface
3661 on high Ethernet traffic.
3662 Defaults to 4 if not defined.
3664 - CONFIG_ENV_MAX_ENTRIES
3666 Maximum number of entries in the hash table that is used
3667 internally to store the environment settings. The default
3668 setting is supposed to be generous and should work in most
3669 cases. This setting can be used to tune behaviour; see
3670 lib/hashtable.c for details.
3672 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3673 - CONFIG_ENV_FLAGS_LIST_STATIC
3674 Enable validation of the values given to environment variables when
3675 calling env set. Variables can be restricted to only decimal,
3676 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3677 the variables can also be restricted to IP address or MAC address.
3679 The format of the list is:
3680 type_attribute = [s|d|x|b|i|m]
3681 access_attribute = [a|r|o|c]
3682 attributes = type_attribute[access_attribute]
3683 entry = variable_name[:attributes]
3686 The type attributes are:
3687 s - String (default)
3690 b - Boolean ([1yYtT|0nNfF])
3694 The access attributes are:
3700 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3701 Define this to a list (string) to define the ".flags"
3702 environment variable in the default or embedded environment.
3704 - CONFIG_ENV_FLAGS_LIST_STATIC
3705 Define this to a list (string) to define validation that
3706 should be done if an entry is not found in the ".flags"
3707 environment variable. To override a setting in the static
3708 list, simply add an entry for the same variable name to the
3711 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3712 regular expression. This allows multiple variables to define the same
3713 flags without explicitly listing them for each variable.
3715 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3716 If defined, don't allow the -f switch to env set override variable
3719 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3720 This is set by OMAP boards for the max time that reset should
3721 be asserted. See doc/README.omap-reset-time for details on how
3722 the value can be calculated on a given board.
3725 If stdint.h is available with your toolchain you can define this
3726 option to enable it. You can provide option 'USE_STDINT=1' when
3727 building U-Boot to enable this.
3729 The following definitions that deal with the placement and management
3730 of environment data (variable area); in general, we support the
3731 following configurations:
3733 - CONFIG_BUILD_ENVCRC:
3735 Builds up envcrc with the target environment so that external utils
3736 may easily extract it and embed it in final U-Boot images.
3738 - CONFIG_ENV_IS_IN_FLASH:
3740 Define this if the environment is in flash memory.
3742 a) The environment occupies one whole flash sector, which is
3743 "embedded" in the text segment with the U-Boot code. This
3744 happens usually with "bottom boot sector" or "top boot
3745 sector" type flash chips, which have several smaller
3746 sectors at the start or the end. For instance, such a
3747 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3748 such a case you would place the environment in one of the
3749 4 kB sectors - with U-Boot code before and after it. With
3750 "top boot sector" type flash chips, you would put the
3751 environment in one of the last sectors, leaving a gap
3752 between U-Boot and the environment.
3754 - CONFIG_ENV_OFFSET:
3756 Offset of environment data (variable area) to the
3757 beginning of flash memory; for instance, with bottom boot
3758 type flash chips the second sector can be used: the offset
3759 for this sector is given here.
3761 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3765 This is just another way to specify the start address of
3766 the flash sector containing the environment (instead of
3769 - CONFIG_ENV_SECT_SIZE:
3771 Size of the sector containing the environment.
3774 b) Sometimes flash chips have few, equal sized, BIG sectors.
3775 In such a case you don't want to spend a whole sector for
3780 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3781 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3782 of this flash sector for the environment. This saves
3783 memory for the RAM copy of the environment.
3785 It may also save flash memory if you decide to use this
3786 when your environment is "embedded" within U-Boot code,
3787 since then the remainder of the flash sector could be used
3788 for U-Boot code. It should be pointed out that this is
3789 STRONGLY DISCOURAGED from a robustness point of view:
3790 updating the environment in flash makes it always
3791 necessary to erase the WHOLE sector. If something goes
3792 wrong before the contents has been restored from a copy in
3793 RAM, your target system will be dead.
3795 - CONFIG_ENV_ADDR_REDUND
3796 CONFIG_ENV_SIZE_REDUND
3798 These settings describe a second storage area used to hold
3799 a redundant copy of the environment data, so that there is
3800 a valid backup copy in case there is a power failure during
3801 a "saveenv" operation.
3803 BE CAREFUL! Any changes to the flash layout, and some changes to the
3804 source code will make it necessary to adapt <board>/u-boot.lds*
3808 - CONFIG_ENV_IS_IN_NVRAM:
3810 Define this if you have some non-volatile memory device
3811 (NVRAM, battery buffered SRAM) which you want to use for the
3817 These two #defines are used to determine the memory area you
3818 want to use for environment. It is assumed that this memory
3819 can just be read and written to, without any special
3822 BE CAREFUL! The first access to the environment happens quite early
3823 in U-Boot initialization (when we try to get the setting of for the
3824 console baudrate). You *MUST* have mapped your NVRAM area then, or
3827 Please note that even with NVRAM we still use a copy of the
3828 environment in RAM: we could work on NVRAM directly, but we want to
3829 keep settings there always unmodified except somebody uses "saveenv"
3830 to save the current settings.
3833 - CONFIG_ENV_IS_IN_EEPROM:
3835 Use this if you have an EEPROM or similar serial access
3836 device and a driver for it.
3838 - CONFIG_ENV_OFFSET:
3841 These two #defines specify the offset and size of the
3842 environment area within the total memory of your EEPROM.
3844 - CONFIG_SYS_I2C_EEPROM_ADDR:
3845 If defined, specified the chip address of the EEPROM device.
3846 The default address is zero.
3848 - CONFIG_SYS_I2C_EEPROM_BUS:
3849 If defined, specified the i2c bus of the EEPROM device.
3851 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3852 If defined, the number of bits used to address bytes in a
3853 single page in the EEPROM device. A 64 byte page, for example
3854 would require six bits.
3856 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3857 If defined, the number of milliseconds to delay between
3858 page writes. The default is zero milliseconds.
3860 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3861 The length in bytes of the EEPROM memory array address. Note
3862 that this is NOT the chip address length!
3864 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3865 EEPROM chips that implement "address overflow" are ones
3866 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3867 address and the extra bits end up in the "chip address" bit
3868 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3871 Note that we consider the length of the address field to
3872 still be one byte because the extra address bits are hidden
3873 in the chip address.
3875 - CONFIG_SYS_EEPROM_SIZE:
3876 The size in bytes of the EEPROM device.
3878 - CONFIG_ENV_EEPROM_IS_ON_I2C
3879 define this, if you have I2C and SPI activated, and your
3880 EEPROM, which holds the environment, is on the I2C bus.
3882 - CONFIG_I2C_ENV_EEPROM_BUS
3883 if you have an Environment on an EEPROM reached over
3884 I2C muxes, you can define here, how to reach this
3885 EEPROM. For example:
3887 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3889 EEPROM which holds the environment, is reached over
3890 a pca9547 i2c mux with address 0x70, channel 3.
3892 - CONFIG_ENV_IS_IN_DATAFLASH:
3894 Define this if you have a DataFlash memory device which you
3895 want to use for the environment.
3897 - CONFIG_ENV_OFFSET:
3901 These three #defines specify the offset and size of the
3902 environment area within the total memory of your DataFlash placed
3903 at the specified address.
3905 - CONFIG_ENV_IS_IN_SPI_FLASH:
3907 Define this if you have a SPI Flash memory device which you
3908 want to use for the environment.
3910 - CONFIG_ENV_OFFSET:
3913 These two #defines specify the offset and size of the
3914 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3915 aligned to an erase sector boundary.
3917 - CONFIG_ENV_SECT_SIZE:
3919 Define the SPI flash's sector size.
3921 - CONFIG_ENV_OFFSET_REDUND (optional):
3923 This setting describes a second storage area of CONFIG_ENV_SIZE
3924 size used to hold a redundant copy of the environment data, so
3925 that there is a valid backup copy in case there is a power failure
3926 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3927 aligned to an erase sector boundary.
3929 - CONFIG_ENV_SPI_BUS (optional):
3930 - CONFIG_ENV_SPI_CS (optional):
3932 Define the SPI bus and chip select. If not defined they will be 0.
3934 - CONFIG_ENV_SPI_MAX_HZ (optional):
3936 Define the SPI max work clock. If not defined then use 1MHz.
3938 - CONFIG_ENV_SPI_MODE (optional):
3940 Define the SPI work mode. If not defined then use SPI_MODE_3.
3942 - CONFIG_ENV_IS_IN_REMOTE:
3944 Define this if you have a remote memory space which you
3945 want to use for the local device's environment.
3950 These two #defines specify the address and size of the
3951 environment area within the remote memory space. The
3952 local device can get the environment from remote memory
3953 space by SRIO or PCIE links.
3955 BE CAREFUL! For some special cases, the local device can not use
3956 "saveenv" command. For example, the local device will get the
3957 environment stored in a remote NOR flash by SRIO or PCIE link,
3958 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3960 - CONFIG_ENV_IS_IN_NAND:
3962 Define this if you have a NAND device which you want to use
3963 for the environment.
3965 - CONFIG_ENV_OFFSET:
3968 These two #defines specify the offset and size of the environment
3969 area within the first NAND device. CONFIG_ENV_OFFSET must be
3970 aligned to an erase block boundary.
3972 - CONFIG_ENV_OFFSET_REDUND (optional):
3974 This setting describes a second storage area of CONFIG_ENV_SIZE
3975 size used to hold a redundant copy of the environment data, so
3976 that there is a valid backup copy in case there is a power failure
3977 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3978 aligned to an erase block boundary.
3980 - CONFIG_ENV_RANGE (optional):
3982 Specifies the length of the region in which the environment
3983 can be written. This should be a multiple of the NAND device's
3984 block size. Specifying a range with more erase blocks than
3985 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3986 the range to be avoided.
3988 - CONFIG_ENV_OFFSET_OOB (optional):
3990 Enables support for dynamically retrieving the offset of the
3991 environment from block zero's out-of-band data. The
3992 "nand env.oob" command can be used to record this offset.
3993 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3994 using CONFIG_ENV_OFFSET_OOB.
3996 - CONFIG_NAND_ENV_DST
3998 Defines address in RAM to which the nand_spl code should copy the
3999 environment. If redundant environment is used, it will be copied to
4000 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4002 - CONFIG_ENV_IS_IN_UBI:
4004 Define this if you have an UBI volume that you want to use for the
4005 environment. This has the benefit of wear-leveling the environment
4006 accesses, which is important on NAND.
4008 - CONFIG_ENV_UBI_PART:
4010 Define this to a string that is the mtd partition containing the UBI.
4012 - CONFIG_ENV_UBI_VOLUME:
4014 Define this to the name of the volume that you want to store the
4017 - CONFIG_ENV_UBI_VOLUME_REDUND:
4019 Define this to the name of another volume to store a second copy of
4020 the environment in. This will enable redundant environments in UBI.
4021 It is assumed that both volumes are in the same MTD partition.
4023 - CONFIG_UBI_SILENCE_MSG
4024 - CONFIG_UBIFS_SILENCE_MSG
4026 You will probably want to define these to avoid a really noisy system
4027 when storing the env in UBI.
4029 - CONFIG_ENV_IS_IN_FAT:
4030 Define this if you want to use the FAT file system for the environment.
4032 - FAT_ENV_INTERFACE:
4034 Define this to a string that is the name of the block device.
4036 - FAT_ENV_DEVICE_AND_PART:
4038 Define this to a string to specify the partition of the device. It can
4041 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4042 - "D:P": device D partition P. Error occurs if device D has no
4045 - "D" or "D:": device D partition 1 if device D has partition
4046 table, or the whole device D if has no partition
4048 - "D:auto": first partition in device D with bootable flag set.
4049 If none, first valid partition in device D. If no
4050 partition table then means device D.
4054 It's a string of the FAT file name. This file use to store the
4058 This should be defined. Otherwise it cannot save the environment file.
4060 - CONFIG_ENV_IS_IN_MMC:
4062 Define this if you have an MMC device which you want to use for the
4065 - CONFIG_SYS_MMC_ENV_DEV:
4067 Specifies which MMC device the environment is stored in.
4069 - CONFIG_SYS_MMC_ENV_PART (optional):
4071 Specifies which MMC partition the environment is stored in. If not
4072 set, defaults to partition 0, the user area. Common values might be
4073 1 (first MMC boot partition), 2 (second MMC boot partition).
4075 - CONFIG_ENV_OFFSET:
4078 These two #defines specify the offset and size of the environment
4079 area within the specified MMC device.
4081 If offset is positive (the usual case), it is treated as relative to
4082 the start of the MMC partition. If offset is negative, it is treated
4083 as relative to the end of the MMC partition. This can be useful if
4084 your board may be fitted with different MMC devices, which have
4085 different sizes for the MMC partitions, and you always want the
4086 environment placed at the very end of the partition, to leave the
4087 maximum possible space before it, to store other data.
4089 These two values are in units of bytes, but must be aligned to an
4090 MMC sector boundary.
4092 - CONFIG_ENV_OFFSET_REDUND (optional):
4094 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4095 hold a redundant copy of the environment data. This provides a
4096 valid backup copy in case the other copy is corrupted, e.g. due
4097 to a power failure during a "saveenv" operation.
4099 This value may also be positive or negative; this is handled in the
4100 same way as CONFIG_ENV_OFFSET.
4102 This value is also in units of bytes, but must also be aligned to
4103 an MMC sector boundary.
4105 - CONFIG_ENV_SIZE_REDUND (optional):
4107 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4108 set. If this value is set, it must be set to the same value as
4111 - CONFIG_SYS_SPI_INIT_OFFSET
4113 Defines offset to the initial SPI buffer area in DPRAM. The
4114 area is used at an early stage (ROM part) if the environment
4115 is configured to reside in the SPI EEPROM: We need a 520 byte
4116 scratch DPRAM area. It is used between the two initialization
4117 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4118 to be a good choice since it makes it far enough from the
4119 start of the data area as well as from the stack pointer.
4121 Please note that the environment is read-only until the monitor
4122 has been relocated to RAM and a RAM copy of the environment has been
4123 created; also, when using EEPROM you will have to use getenv_f()
4124 until then to read environment variables.
4126 The environment is protected by a CRC32 checksum. Before the monitor
4127 is relocated into RAM, as a result of a bad CRC you will be working
4128 with the compiled-in default environment - *silently*!!! [This is
4129 necessary, because the first environment variable we need is the
4130 "baudrate" setting for the console - if we have a bad CRC, we don't
4131 have any device yet where we could complain.]
4133 Note: once the monitor has been relocated, then it will complain if
4134 the default environment is used; a new CRC is computed as soon as you
4135 use the "saveenv" command to store a valid environment.
4137 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4138 Echo the inverted Ethernet link state to the fault LED.
4140 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4141 also needs to be defined.
4143 - CONFIG_SYS_FAULT_MII_ADDR:
4144 MII address of the PHY to check for the Ethernet link state.
4146 - CONFIG_NS16550_MIN_FUNCTIONS:
4147 Define this if you desire to only have use of the NS16550_init
4148 and NS16550_putc functions for the serial driver located at
4149 drivers/serial/ns16550.c. This option is useful for saving
4150 space for already greatly restricted images, including but not
4151 limited to NAND_SPL configurations.
4153 - CONFIG_DISPLAY_BOARDINFO
4154 Display information about the board that U-Boot is running on
4155 when U-Boot starts up. The board function checkboard() is called
4158 - CONFIG_DISPLAY_BOARDINFO_LATE
4159 Similar to the previous option, but display this information
4160 later, once stdio is running and output goes to the LCD, if
4163 - CONFIG_BOARD_SIZE_LIMIT:
4164 Maximum size of the U-Boot image. When defined, the
4165 build system checks that the actual size does not
4168 Low Level (hardware related) configuration options:
4169 ---------------------------------------------------
4171 - CONFIG_SYS_CACHELINE_SIZE:
4172 Cache Line Size of the CPU.
4174 - CONFIG_SYS_DEFAULT_IMMR:
4175 Default address of the IMMR after system reset.
4177 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4178 and RPXsuper) to be able to adjust the position of
4179 the IMMR register after a reset.
4181 - CONFIG_SYS_CCSRBAR_DEFAULT:
4182 Default (power-on reset) physical address of CCSR on Freescale
4185 - CONFIG_SYS_CCSRBAR:
4186 Virtual address of CCSR. On a 32-bit build, this is typically
4187 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4189 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4190 for cross-platform code that uses that macro instead.
4192 - CONFIG_SYS_CCSRBAR_PHYS:
4193 Physical address of CCSR. CCSR can be relocated to a new
4194 physical address, if desired. In this case, this macro should
4195 be set to that address. Otherwise, it should be set to the
4196 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4197 is typically relocated on 36-bit builds. It is recommended
4198 that this macro be defined via the _HIGH and _LOW macros:
4200 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4201 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4203 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4204 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4205 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4206 used in assembly code, so it must not contain typecasts or
4207 integer size suffixes (e.g. "ULL").
4209 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4210 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4211 used in assembly code, so it must not contain typecasts or
4212 integer size suffixes (e.g. "ULL").
4214 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4215 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4216 forced to a value that ensures that CCSR is not relocated.
4218 - Floppy Disk Support:
4219 CONFIG_SYS_FDC_DRIVE_NUMBER
4221 the default drive number (default value 0)
4223 CONFIG_SYS_ISA_IO_STRIDE
4225 defines the spacing between FDC chipset registers
4228 CONFIG_SYS_ISA_IO_OFFSET
4230 defines the offset of register from address. It
4231 depends on which part of the data bus is connected to
4232 the FDC chipset. (default value 0)
4234 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4235 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4238 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4239 fdc_hw_init() is called at the beginning of the FDC
4240 setup. fdc_hw_init() must be provided by the board
4241 source code. It is used to make hardware-dependent
4245 Most IDE controllers were designed to be connected with PCI
4246 interface. Only few of them were designed for AHB interface.
4247 When software is doing ATA command and data transfer to
4248 IDE devices through IDE-AHB controller, some additional
4249 registers accessing to these kind of IDE-AHB controller
4252 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4253 DO NOT CHANGE unless you know exactly what you're
4254 doing! (11-4) [MPC8xx/82xx systems only]
4256 - CONFIG_SYS_INIT_RAM_ADDR:
4258 Start address of memory area that can be used for
4259 initial data and stack; please note that this must be
4260 writable memory that is working WITHOUT special
4261 initialization, i. e. you CANNOT use normal RAM which
4262 will become available only after programming the
4263 memory controller and running certain initialization
4266 U-Boot uses the following memory types:
4267 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4268 - MPC824X: data cache
4269 - PPC4xx: data cache
4271 - CONFIG_SYS_GBL_DATA_OFFSET:
4273 Offset of the initial data structure in the memory
4274 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4275 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4276 data is located at the end of the available space
4277 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4278 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4279 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4280 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4283 On the MPC824X (or other systems that use the data
4284 cache for initial memory) the address chosen for
4285 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4286 point to an otherwise UNUSED address space between
4287 the top of RAM and the start of the PCI space.
4289 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4291 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4293 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4295 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4297 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4299 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4301 - CONFIG_SYS_OR_TIMING_SDRAM:
4304 - CONFIG_SYS_MAMR_PTA:
4305 periodic timer for refresh
4307 - CONFIG_SYS_DER: Debug Event Register (37-47)
4309 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4310 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4311 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4312 CONFIG_SYS_BR1_PRELIM:
4313 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4315 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4316 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4317 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4318 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4320 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4321 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4322 Machine Mode Register and Memory Periodic Timer
4323 Prescaler definitions (SDRAM timing)
4325 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4326 enable I2C microcode relocation patch (MPC8xx);
4327 define relocation offset in DPRAM [DSP2]
4329 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4330 enable SMC microcode relocation patch (MPC8xx);
4331 define relocation offset in DPRAM [SMC1]
4333 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4334 enable SPI microcode relocation patch (MPC8xx);
4335 define relocation offset in DPRAM [SCC4]
4337 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4338 Offset of the bootmode word in DPRAM used by post
4339 (Power On Self Tests). This definition overrides
4340 #define'd default value in commproc.h resp.
4343 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4344 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4345 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4346 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4347 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4348 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4349 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4350 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4351 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4353 - CONFIG_PCI_DISABLE_PCIE:
4354 Disable PCI-Express on systems where it is supported but not
4357 - CONFIG_PCI_ENUM_ONLY
4358 Only scan through and get the devices on the buses.
4359 Don't do any setup work, presumably because someone or
4360 something has already done it, and we don't need to do it
4361 a second time. Useful for platforms that are pre-booted
4362 by coreboot or similar.
4364 - CONFIG_PCI_INDIRECT_BRIDGE:
4365 Enable support for indirect PCI bridges.
4368 Chip has SRIO or not
4371 Board has SRIO 1 port available
4374 Board has SRIO 2 port available
4376 - CONFIG_SRIO_PCIE_BOOT_MASTER
4377 Board can support master function for Boot from SRIO and PCIE
4379 - CONFIG_SYS_SRIOn_MEM_VIRT:
4380 Virtual Address of SRIO port 'n' memory region
4382 - CONFIG_SYS_SRIOn_MEM_PHYS:
4383 Physical Address of SRIO port 'n' memory region
4385 - CONFIG_SYS_SRIOn_MEM_SIZE:
4386 Size of SRIO port 'n' memory region
4388 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4389 Defined to tell the NAND controller that the NAND chip is using
4391 Not all NAND drivers use this symbol.
4392 Example of drivers that use it:
4393 - drivers/mtd/nand/ndfc.c
4394 - drivers/mtd/nand/mxc_nand.c
4396 - CONFIG_SYS_NDFC_EBC0_CFG
4397 Sets the EBC0_CFG register for the NDFC. If not defined
4398 a default value will be used.
4401 Get DDR timing information from an I2C EEPROM. Common
4402 with pluggable memory modules such as SODIMMs
4405 I2C address of the SPD EEPROM
4407 - CONFIG_SYS_SPD_BUS_NUM
4408 If SPD EEPROM is on an I2C bus other than the first
4409 one, specify here. Note that the value must resolve
4410 to something your driver can deal with.
4412 - CONFIG_SYS_DDR_RAW_TIMING
4413 Get DDR timing information from other than SPD. Common with
4414 soldered DDR chips onboard without SPD. DDR raw timing
4415 parameters are extracted from datasheet and hard-coded into
4416 header files or board specific files.
4418 - CONFIG_FSL_DDR_INTERACTIVE
4419 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4421 - CONFIG_FSL_DDR_SYNC_REFRESH
4422 Enable sync of refresh for multiple controllers.
4424 - CONFIG_FSL_DDR_BIST
4425 Enable built-in memory test for Freescale DDR controllers.
4427 - CONFIG_SYS_83XX_DDR_USES_CS0
4428 Only for 83xx systems. If specified, then DDR should
4429 be configured using CS0 and CS1 instead of CS2 and CS3.
4431 - CONFIG_ETHER_ON_FEC[12]
4432 Define to enable FEC[12] on a 8xx series processor.
4434 - CONFIG_FEC[12]_PHY
4435 Define to the hardcoded PHY address which corresponds
4436 to the given FEC; i. e.
4437 #define CONFIG_FEC1_PHY 4
4438 means that the PHY with address 4 is connected to FEC1
4440 When set to -1, means to probe for first available.
4442 - CONFIG_FEC[12]_PHY_NORXERR
4443 The PHY does not have a RXERR line (RMII only).
4444 (so program the FEC to ignore it).
4447 Enable RMII mode for all FECs.
4448 Note that this is a global option, we can't
4449 have one FEC in standard MII mode and another in RMII mode.
4451 - CONFIG_CRC32_VERIFY
4452 Add a verify option to the crc32 command.
4455 => crc32 -v <address> <count> <crc32>
4457 Where address/count indicate a memory area
4458 and crc32 is the correct crc32 which the
4462 Add the "loopw" memory command. This only takes effect if
4463 the memory commands are activated globally (CONFIG_CMD_MEM).
4466 Add the "mdc" and "mwc" memory commands. These are cyclic
4471 This command will print 4 bytes (10,11,12,13) each 500 ms.
4473 => mwc.l 100 12345678 10
4474 This command will write 12345678 to address 100 all 10 ms.
4476 This only takes effect if the memory commands are activated
4477 globally (CONFIG_CMD_MEM).
4479 - CONFIG_SKIP_LOWLEVEL_INIT
4480 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4481 low level initializations (like setting up the memory
4482 controller) are omitted and/or U-Boot does not
4483 relocate itself into RAM.
4485 Normally this variable MUST NOT be defined. The only
4486 exception is when U-Boot is loaded (to RAM) by some
4487 other boot loader or by a debugger which performs
4488 these initializations itself.
4490 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4491 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4492 to be skipped. The normal CP15 init (such as enabling the
4493 instruction cache) is still performed.
4496 Modifies the behaviour of start.S when compiling a loader
4497 that is executed before the actual U-Boot. E.g. when
4498 compiling a NAND SPL.
4501 Modifies the behaviour of start.S when compiling a loader
4502 that is executed after the SPL and before the actual U-Boot.
4503 It is loaded by the SPL.
4505 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4506 Only for 85xx systems. If this variable is specified, the section
4507 .resetvec is not kept and the section .bootpg is placed in the
4508 previous 4k of the .text section.
4510 - CONFIG_ARCH_MAP_SYSMEM
4511 Generally U-Boot (and in particular the md command) uses
4512 effective address. It is therefore not necessary to regard
4513 U-Boot address as virtual addresses that need to be translated
4514 to physical addresses. However, sandbox requires this, since
4515 it maintains its own little RAM buffer which contains all
4516 addressable memory. This option causes some memory accesses
4517 to be mapped through map_sysmem() / unmap_sysmem().
4519 - CONFIG_X86_RESET_VECTOR
4520 If defined, the x86 reset vector code is included. This is not
4521 needed when U-Boot is running from Coreboot.
4524 Defines the MPU clock speed (in MHz).
4526 NOTE : currently only supported on AM335x platforms.
4528 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4529 Enables the RTC32K OSC on AM33xx based plattforms
4531 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4532 Option to disable subpage write in NAND driver
4533 driver that uses this:
4534 drivers/mtd/nand/davinci_nand.c
4536 Freescale QE/FMAN Firmware Support:
4537 -----------------------------------
4539 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4540 loading of "firmware", which is encoded in the QE firmware binary format.
4541 This firmware often needs to be loaded during U-Boot booting, so macros
4542 are used to identify the storage device (NOR flash, SPI, etc) and the address
4545 - CONFIG_SYS_FMAN_FW_ADDR
4546 The address in the storage device where the FMAN microcode is located. The
4547 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4550 - CONFIG_SYS_QE_FW_ADDR
4551 The address in the storage device where the QE microcode is located. The
4552 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4555 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4556 The maximum possible size of the firmware. The firmware binary format
4557 has a field that specifies the actual size of the firmware, but it
4558 might not be possible to read any part of the firmware unless some
4559 local storage is allocated to hold the entire firmware first.
4561 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4562 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4563 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4564 virtual address in NOR flash.
4566 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4567 Specifies that QE/FMAN firmware is located in NAND flash.
4568 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4570 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4571 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4572 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4574 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4575 Specifies that QE/FMAN firmware is located in the remote (master)
4576 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4577 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4578 window->master inbound window->master LAW->the ucode address in
4579 master's memory space.
4581 Freescale Layerscape Management Complex Firmware Support:
4582 ---------------------------------------------------------
4583 The Freescale Layerscape Management Complex (MC) supports the loading of
4585 This firmware often needs to be loaded during U-Boot booting, so macros
4586 are used to identify the storage device (NOR flash, SPI, etc) and the address
4589 - CONFIG_FSL_MC_ENET
4590 Enable the MC driver for Layerscape SoCs.
4592 Freescale Layerscape Debug Server Support:
4593 -------------------------------------------
4594 The Freescale Layerscape Debug Server Support supports the loading of
4595 "Debug Server firmware" and triggering SP boot-rom.
4596 This firmware often needs to be loaded during U-Boot booting.
4598 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4599 Define alignment of reserved memory MC requires
4604 In order to achieve reproducible builds, timestamps used in the U-Boot build
4605 process have to be set to a fixed value.
4607 This is done using the SOURCE_DATE_EPOCH environment variable.
4608 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4609 option for U-Boot or an environment variable in U-Boot.
4611 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4613 Building the Software:
4614 ======================
4616 Building U-Boot has been tested in several native build environments
4617 and in many different cross environments. Of course we cannot support
4618 all possibly existing versions of cross development tools in all
4619 (potentially obsolete) versions. In case of tool chain problems we
4620 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4621 which is extensively used to build and test U-Boot.
4623 If you are not using a native environment, it is assumed that you
4624 have GNU cross compiling tools available in your path. In this case,
4625 you must set the environment variable CROSS_COMPILE in your shell.
4626 Note that no changes to the Makefile or any other source files are
4627 necessary. For example using the ELDK on a 4xx CPU, please enter:
4629 $ CROSS_COMPILE=ppc_4xx-
4630 $ export CROSS_COMPILE
4632 Note: If you wish to generate Windows versions of the utilities in
4633 the tools directory you can use the MinGW toolchain
4634 (http://www.mingw.org). Set your HOST tools to the MinGW
4635 toolchain and execute 'make tools'. For example:
4637 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4639 Binaries such as tools/mkimage.exe will be created which can
4640 be executed on computers running Windows.
4642 U-Boot is intended to be simple to build. After installing the
4643 sources you must configure U-Boot for one specific board type. This
4648 where "NAME_defconfig" is the name of one of the existing configu-
4649 rations; see boards.cfg for supported names.
4651 Note: for some board special configuration names may exist; check if
4652 additional information is available from the board vendor; for
4653 instance, the TQM823L systems are available without (standard)
4654 or with LCD support. You can select such additional "features"
4655 when choosing the configuration, i. e.
4657 make TQM823L_defconfig
4658 - will configure for a plain TQM823L, i. e. no LCD support
4660 make TQM823L_LCD_defconfig
4661 - will configure for a TQM823L with U-Boot console on LCD
4666 Finally, type "make all", and you should get some working U-Boot
4667 images ready for download to / installation on your system:
4669 - "u-boot.bin" is a raw binary image
4670 - "u-boot" is an image in ELF binary format
4671 - "u-boot.srec" is in Motorola S-Record format
4673 By default the build is performed locally and the objects are saved
4674 in the source directory. One of the two methods can be used to change
4675 this behavior and build U-Boot to some external directory:
4677 1. Add O= to the make command line invocations:
4679 make O=/tmp/build distclean
4680 make O=/tmp/build NAME_defconfig
4681 make O=/tmp/build all
4683 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4685 export KBUILD_OUTPUT=/tmp/build
4690 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4694 Please be aware that the Makefiles assume you are using GNU make, so
4695 for instance on NetBSD you might need to use "gmake" instead of
4699 If the system board that you have is not listed, then you will need
4700 to port U-Boot to your hardware platform. To do this, follow these
4703 1. Create a new directory to hold your board specific code. Add any
4704 files you need. In your board directory, you will need at least
4705 the "Makefile" and a "<board>.c".
4706 2. Create a new configuration file "include/configs/<board>.h" for
4708 3. If you're porting U-Boot to a new CPU, then also create a new
4709 directory to hold your CPU specific code. Add any files you need.
4710 4. Run "make <board>_defconfig" with your new name.
4711 5. Type "make", and you should get a working "u-boot.srec" file
4712 to be installed on your target system.
4713 6. Debug and solve any problems that might arise.
4714 [Of course, this last step is much harder than it sounds.]
4717 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4718 ==============================================================
4720 If you have modified U-Boot sources (for instance added a new board
4721 or support for new devices, a new CPU, etc.) you are expected to
4722 provide feedback to the other developers. The feedback normally takes
4723 the form of a "patch", i. e. a context diff against a certain (latest
4724 official or latest in the git repository) version of U-Boot sources.
4726 But before you submit such a patch, please verify that your modifi-
4727 cation did not break existing code. At least make sure that *ALL* of
4728 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4729 just run the buildman script (tools/buildman/buildman), which will
4730 configure and build U-Boot for ALL supported system. Be warned, this
4731 will take a while. Please see the buildman README, or run 'buildman -H'
4735 See also "U-Boot Porting Guide" below.
4738 Monitor Commands - Overview:
4739 ============================
4741 go - start application at address 'addr'
4742 run - run commands in an environment variable
4743 bootm - boot application image from memory
4744 bootp - boot image via network using BootP/TFTP protocol
4745 bootz - boot zImage from memory
4746 tftpboot- boot image via network using TFTP protocol
4747 and env variables "ipaddr" and "serverip"
4748 (and eventually "gatewayip")
4749 tftpput - upload a file via network using TFTP protocol
4750 rarpboot- boot image via network using RARP/TFTP protocol
4751 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4752 loads - load S-Record file over serial line
4753 loadb - load binary file over serial line (kermit mode)
4755 mm - memory modify (auto-incrementing)
4756 nm - memory modify (constant address)
4757 mw - memory write (fill)
4759 cmp - memory compare
4760 crc32 - checksum calculation
4761 i2c - I2C sub-system
4762 sspi - SPI utility commands
4763 base - print or set address offset
4764 printenv- print environment variables
4765 setenv - set environment variables
4766 saveenv - save environment variables to persistent storage
4767 protect - enable or disable FLASH write protection
4768 erase - erase FLASH memory
4769 flinfo - print FLASH memory information
4770 nand - NAND memory operations (see doc/README.nand)
4771 bdinfo - print Board Info structure
4772 iminfo - print header information for application image
4773 coninfo - print console devices and informations
4774 ide - IDE sub-system
4775 loop - infinite loop on address range
4776 loopw - infinite write loop on address range
4777 mtest - simple RAM test
4778 icache - enable or disable instruction cache
4779 dcache - enable or disable data cache
4780 reset - Perform RESET of the CPU
4781 echo - echo args to console
4782 version - print monitor version
4783 help - print online help
4784 ? - alias for 'help'
4787 Monitor Commands - Detailed Description:
4788 ========================================
4792 For now: just type "help <command>".
4795 Environment Variables:
4796 ======================
4798 U-Boot supports user configuration using Environment Variables which
4799 can be made persistent by saving to Flash memory.
4801 Environment Variables are set using "setenv", printed using
4802 "printenv", and saved to Flash using "saveenv". Using "setenv"
4803 without a value can be used to delete a variable from the
4804 environment. As long as you don't save the environment you are
4805 working with an in-memory copy. In case the Flash area containing the
4806 environment is erased by accident, a default environment is provided.
4808 Some configuration options can be set using Environment Variables.
4810 List of environment variables (most likely not complete):
4812 baudrate - see CONFIG_BAUDRATE
4814 bootdelay - see CONFIG_BOOTDELAY
4816 bootcmd - see CONFIG_BOOTCOMMAND
4818 bootargs - Boot arguments when booting an RTOS image
4820 bootfile - Name of the image to load with TFTP
4822 bootm_low - Memory range available for image processing in the bootm
4823 command can be restricted. This variable is given as
4824 a hexadecimal number and defines lowest address allowed
4825 for use by the bootm command. See also "bootm_size"
4826 environment variable. Address defined by "bootm_low" is
4827 also the base of the initial memory mapping for the Linux
4828 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4831 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4832 This variable is given as a hexadecimal number and it
4833 defines the size of the memory region starting at base
4834 address bootm_low that is accessible by the Linux kernel
4835 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4836 as the default value if it is defined, and bootm_size is
4839 bootm_size - Memory range available for image processing in the bootm
4840 command can be restricted. This variable is given as
4841 a hexadecimal number and defines the size of the region
4842 allowed for use by the bootm command. See also "bootm_low"
4843 environment variable.
4845 updatefile - Location of the software update file on a TFTP server, used
4846 by the automatic software update feature. Please refer to
4847 documentation in doc/README.update for more details.
4849 autoload - if set to "no" (any string beginning with 'n'),
4850 "bootp" will just load perform a lookup of the
4851 configuration from the BOOTP server, but not try to
4852 load any image using TFTP
4854 autostart - if set to "yes", an image loaded using the "bootp",
4855 "rarpboot", "tftpboot" or "diskboot" commands will
4856 be automatically started (by internally calling
4859 If set to "no", a standalone image passed to the
4860 "bootm" command will be copied to the load address
4861 (and eventually uncompressed), but NOT be started.
4862 This can be used to load and uncompress arbitrary
4865 fdt_high - if set this restricts the maximum address that the
4866 flattened device tree will be copied into upon boot.
4867 For example, if you have a system with 1 GB memory
4868 at physical address 0x10000000, while Linux kernel
4869 only recognizes the first 704 MB as low memory, you
4870 may need to set fdt_high as 0x3C000000 to have the
4871 device tree blob be copied to the maximum address
4872 of the 704 MB low memory, so that Linux kernel can
4873 access it during the boot procedure.
4875 If this is set to the special value 0xFFFFFFFF then
4876 the fdt will not be copied at all on boot. For this
4877 to work it must reside in writable memory, have
4878 sufficient padding on the end of it for u-boot to
4879 add the information it needs into it, and the memory
4880 must be accessible by the kernel.
4882 fdtcontroladdr- if set this is the address of the control flattened
4883 device tree used by U-Boot when CONFIG_OF_CONTROL is
4886 i2cfast - (PPC405GP|PPC405EP only)
4887 if set to 'y' configures Linux I2C driver for fast
4888 mode (400kHZ). This environment variable is used in
4889 initialization code. So, for changes to be effective
4890 it must be saved and board must be reset.
4892 initrd_high - restrict positioning of initrd images:
4893 If this variable is not set, initrd images will be
4894 copied to the highest possible address in RAM; this
4895 is usually what you want since it allows for
4896 maximum initrd size. If for some reason you want to
4897 make sure that the initrd image is loaded below the
4898 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4899 variable to a value of "no" or "off" or "0".
4900 Alternatively, you can set it to a maximum upper
4901 address to use (U-Boot will still check that it
4902 does not overwrite the U-Boot stack and data).
4904 For instance, when you have a system with 16 MB
4905 RAM, and want to reserve 4 MB from use by Linux,
4906 you can do this by adding "mem=12M" to the value of
4907 the "bootargs" variable. However, now you must make
4908 sure that the initrd image is placed in the first
4909 12 MB as well - this can be done with
4911 setenv initrd_high 00c00000
4913 If you set initrd_high to 0xFFFFFFFF, this is an
4914 indication to U-Boot that all addresses are legal
4915 for the Linux kernel, including addresses in flash
4916 memory. In this case U-Boot will NOT COPY the
4917 ramdisk at all. This may be useful to reduce the
4918 boot time on your system, but requires that this
4919 feature is supported by your Linux kernel.
4921 ipaddr - IP address; needed for tftpboot command
4923 loadaddr - Default load address for commands like "bootp",
4924 "rarpboot", "tftpboot", "loadb" or "diskboot"
4926 loads_echo - see CONFIG_LOADS_ECHO
4928 serverip - TFTP server IP address; needed for tftpboot command
4930 bootretry - see CONFIG_BOOT_RETRY_TIME
4932 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4934 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4936 ethprime - controls which interface is used first.
4938 ethact - controls which interface is currently active.
4939 For example you can do the following
4941 => setenv ethact FEC
4942 => ping 192.168.0.1 # traffic sent on FEC
4943 => setenv ethact SCC
4944 => ping 10.0.0.1 # traffic sent on SCC
4946 ethrotate - When set to "no" U-Boot does not go through all
4947 available network interfaces.
4948 It just stays at the currently selected interface.
4950 netretry - When set to "no" each network operation will
4951 either succeed or fail without retrying.
4952 When set to "once" the network operation will
4953 fail when all the available network interfaces
4954 are tried once without success.
4955 Useful on scripts which control the retry operation
4958 npe_ucode - set load address for the NPE microcode
4960 silent_linux - If set then Linux will be told to boot silently, by
4961 changing the console to be empty. If "yes" it will be
4962 made silent. If "no" it will not be made silent. If
4963 unset, then it will be made silent if the U-Boot console
4966 tftpsrcp - If this is set, the value is used for TFTP's
4969 tftpdstp - If this is set, the value is used for TFTP's UDP
4970 destination port instead of the Well Know Port 69.
4972 tftpblocksize - Block size to use for TFTP transfers; if not set,
4973 we use the TFTP server's default block size
4975 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4976 seconds, minimum value is 1000 = 1 second). Defines
4977 when a packet is considered to be lost so it has to
4978 be retransmitted. The default is 5000 = 5 seconds.
4979 Lowering this value may make downloads succeed
4980 faster in networks with high packet loss rates or
4981 with unreliable TFTP servers.
4983 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4984 unit, minimum value = 0). Defines how many timeouts
4985 can happen during a single file transfer before that
4986 transfer is aborted. The default is 10, and 0 means
4987 'no timeouts allowed'. Increasing this value may help
4988 downloads succeed with high packet loss rates, or with
4989 unreliable TFTP servers or client hardware.
4991 vlan - When set to a value < 4095 the traffic over
4992 Ethernet is encapsulated/received over 802.1q
4995 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4996 Unsigned value, in milliseconds. If not set, the period will
4997 be either the default (28000), or a value based on
4998 CONFIG_NET_RETRY_COUNT, if defined. This value has
4999 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5001 The following image location variables contain the location of images
5002 used in booting. The "Image" column gives the role of the image and is
5003 not an environment variable name. The other columns are environment
5004 variable names. "File Name" gives the name of the file on a TFTP
5005 server, "RAM Address" gives the location in RAM the image will be
5006 loaded to, and "Flash Location" gives the image's address in NOR
5007 flash or offset in NAND flash.
5009 *Note* - these variables don't have to be defined for all boards, some
5010 boards currently use other variables for these purposes, and some
5011 boards use these variables for other purposes.
5013 Image File Name RAM Address Flash Location
5014 ----- --------- ----------- --------------
5015 u-boot u-boot u-boot_addr_r u-boot_addr
5016 Linux kernel bootfile kernel_addr_r kernel_addr
5017 device tree blob fdtfile fdt_addr_r fdt_addr
5018 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5020 The following environment variables may be used and automatically
5021 updated by the network boot commands ("bootp" and "rarpboot"),
5022 depending the information provided by your boot server:
5024 bootfile - see above
5025 dnsip - IP address of your Domain Name Server
5026 dnsip2 - IP address of your secondary Domain Name Server
5027 gatewayip - IP address of the Gateway (Router) to use
5028 hostname - Target hostname
5030 netmask - Subnet Mask
5031 rootpath - Pathname of the root filesystem on the NFS server
5032 serverip - see above
5035 There are two special Environment Variables:
5037 serial# - contains hardware identification information such
5038 as type string and/or serial number
5039 ethaddr - Ethernet address
5041 These variables can be set only once (usually during manufacturing of
5042 the board). U-Boot refuses to delete or overwrite these variables
5043 once they have been set once.
5046 Further special Environment Variables:
5048 ver - Contains the U-Boot version string as printed
5049 with the "version" command. This variable is
5050 readonly (see CONFIG_VERSION_VARIABLE).
5053 Please note that changes to some configuration parameters may take
5054 only effect after the next boot (yes, that's just like Windoze :-).
5057 Callback functions for environment variables:
5058 ---------------------------------------------
5060 For some environment variables, the behavior of u-boot needs to change
5061 when their values are changed. This functionality allows functions to
5062 be associated with arbitrary variables. On creation, overwrite, or
5063 deletion, the callback will provide the opportunity for some side
5064 effect to happen or for the change to be rejected.
5066 The callbacks are named and associated with a function using the
5067 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5069 These callbacks are associated with variables in one of two ways. The
5070 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5071 in the board configuration to a string that defines a list of
5072 associations. The list must be in the following format:
5074 entry = variable_name[:callback_name]
5077 If the callback name is not specified, then the callback is deleted.
5078 Spaces are also allowed anywhere in the list.
5080 Callbacks can also be associated by defining the ".callbacks" variable
5081 with the same list format above. Any association in ".callbacks" will
5082 override any association in the static list. You can define
5083 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5084 ".callbacks" environment variable in the default or embedded environment.
5086 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5087 regular expression. This allows multiple variables to be connected to
5088 the same callback without explicitly listing them all out.
5091 Command Line Parsing:
5092 =====================
5094 There are two different command line parsers available with U-Boot:
5095 the old "simple" one, and the much more powerful "hush" shell:
5097 Old, simple command line parser:
5098 --------------------------------
5100 - supports environment variables (through setenv / saveenv commands)
5101 - several commands on one line, separated by ';'
5102 - variable substitution using "... ${name} ..." syntax
5103 - special characters ('$', ';') can be escaped by prefixing with '\',
5105 setenv bootcmd bootm \${address}
5106 - You can also escape text by enclosing in single apostrophes, for example:
5107 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5112 - similar to Bourne shell, with control structures like
5113 if...then...else...fi, for...do...done; while...do...done,
5114 until...do...done, ...
5115 - supports environment ("global") variables (through setenv / saveenv
5116 commands) and local shell variables (through standard shell syntax
5117 "name=value"); only environment variables can be used with "run"
5123 (1) If a command line (or an environment variable executed by a "run"
5124 command) contains several commands separated by semicolon, and
5125 one of these commands fails, then the remaining commands will be
5128 (2) If you execute several variables with one call to run (i. e.
5129 calling run with a list of variables as arguments), any failing
5130 command will cause "run" to terminate, i. e. the remaining
5131 variables are not executed.
5133 Note for Redundant Ethernet Interfaces:
5134 =======================================
5136 Some boards come with redundant Ethernet interfaces; U-Boot supports
5137 such configurations and is capable of automatic selection of a
5138 "working" interface when needed. MAC assignment works as follows:
5140 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5141 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5142 "eth1addr" (=>eth1), "eth2addr", ...
5144 If the network interface stores some valid MAC address (for instance
5145 in SROM), this is used as default address if there is NO correspon-
5146 ding setting in the environment; if the corresponding environment
5147 variable is set, this overrides the settings in the card; that means:
5149 o If the SROM has a valid MAC address, and there is no address in the
5150 environment, the SROM's address is used.
5152 o If there is no valid address in the SROM, and a definition in the
5153 environment exists, then the value from the environment variable is
5156 o If both the SROM and the environment contain a MAC address, and
5157 both addresses are the same, this MAC address is used.
5159 o If both the SROM and the environment contain a MAC address, and the
5160 addresses differ, the value from the environment is used and a
5163 o If neither SROM nor the environment contain a MAC address, an error
5164 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5165 a random, locally-assigned MAC is used.
5167 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5168 will be programmed into hardware as part of the initialization process. This
5169 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5170 The naming convention is as follows:
5171 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5176 U-Boot is capable of booting (and performing other auxiliary operations on)
5177 images in two formats:
5179 New uImage format (FIT)
5180 -----------------------
5182 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5183 to Flattened Device Tree). It allows the use of images with multiple
5184 components (several kernels, ramdisks, etc.), with contents protected by
5185 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5191 Old image format is based on binary files which can be basically anything,
5192 preceded by a special header; see the definitions in include/image.h for
5193 details; basically, the header defines the following image properties:
5195 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5196 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5197 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5198 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5200 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5201 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5202 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5203 * Compression Type (uncompressed, gzip, bzip2)
5209 The header is marked by a special Magic Number, and both the header
5210 and the data portions of the image are secured against corruption by
5217 Although U-Boot should support any OS or standalone application
5218 easily, the main focus has always been on Linux during the design of
5221 U-Boot includes many features that so far have been part of some
5222 special "boot loader" code within the Linux kernel. Also, any
5223 "initrd" images to be used are no longer part of one big Linux image;
5224 instead, kernel and "initrd" are separate images. This implementation
5225 serves several purposes:
5227 - the same features can be used for other OS or standalone
5228 applications (for instance: using compressed images to reduce the
5229 Flash memory footprint)
5231 - it becomes much easier to port new Linux kernel versions because
5232 lots of low-level, hardware dependent stuff are done by U-Boot
5234 - the same Linux kernel image can now be used with different "initrd"
5235 images; of course this also means that different kernel images can
5236 be run with the same "initrd". This makes testing easier (you don't
5237 have to build a new "zImage.initrd" Linux image when you just
5238 change a file in your "initrd"). Also, a field-upgrade of the
5239 software is easier now.
5245 Porting Linux to U-Boot based systems:
5246 ---------------------------------------
5248 U-Boot cannot save you from doing all the necessary modifications to
5249 configure the Linux device drivers for use with your target hardware
5250 (no, we don't intend to provide a full virtual machine interface to
5253 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5255 Just make sure your machine specific header file (for instance
5256 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5257 Information structure as we define in include/asm-<arch>/u-boot.h,
5258 and make sure that your definition of IMAP_ADDR uses the same value
5259 as your U-Boot configuration in CONFIG_SYS_IMMR.
5261 Note that U-Boot now has a driver model, a unified model for drivers.
5262 If you are adding a new driver, plumb it into driver model. If there
5263 is no uclass available, you are encouraged to create one. See
5267 Configuring the Linux kernel:
5268 -----------------------------
5270 No specific requirements for U-Boot. Make sure you have some root
5271 device (initial ramdisk, NFS) for your target system.
5274 Building a Linux Image:
5275 -----------------------
5277 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5278 not used. If you use recent kernel source, a new build target
5279 "uImage" will exist which automatically builds an image usable by
5280 U-Boot. Most older kernels also have support for a "pImage" target,
5281 which was introduced for our predecessor project PPCBoot and uses a
5282 100% compatible format.
5286 make TQM850L_defconfig
5291 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5292 encapsulate a compressed Linux kernel image with header information,
5293 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5295 * build a standard "vmlinux" kernel image (in ELF binary format):
5297 * convert the kernel into a raw binary image:
5299 ${CROSS_COMPILE}-objcopy -O binary \
5300 -R .note -R .comment \
5301 -S vmlinux linux.bin
5303 * compress the binary image:
5307 * package compressed binary image for U-Boot:
5309 mkimage -A ppc -O linux -T kernel -C gzip \
5310 -a 0 -e 0 -n "Linux Kernel Image" \
5311 -d linux.bin.gz uImage
5314 The "mkimage" tool can also be used to create ramdisk images for use
5315 with U-Boot, either separated from the Linux kernel image, or
5316 combined into one file. "mkimage" encapsulates the images with a 64
5317 byte header containing information about target architecture,
5318 operating system, image type, compression method, entry points, time
5319 stamp, CRC32 checksums, etc.
5321 "mkimage" can be called in two ways: to verify existing images and
5322 print the header information, or to build new images.
5324 In the first form (with "-l" option) mkimage lists the information
5325 contained in the header of an existing U-Boot image; this includes
5326 checksum verification:
5328 tools/mkimage -l image
5329 -l ==> list image header information
5331 The second form (with "-d" option) is used to build a U-Boot image
5332 from a "data file" which is used as image payload:
5334 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5335 -n name -d data_file image
5336 -A ==> set architecture to 'arch'
5337 -O ==> set operating system to 'os'
5338 -T ==> set image type to 'type'
5339 -C ==> set compression type 'comp'
5340 -a ==> set load address to 'addr' (hex)
5341 -e ==> set entry point to 'ep' (hex)
5342 -n ==> set image name to 'name'
5343 -d ==> use image data from 'datafile'
5345 Right now, all Linux kernels for PowerPC systems use the same load
5346 address (0x00000000), but the entry point address depends on the
5349 - 2.2.x kernels have the entry point at 0x0000000C,
5350 - 2.3.x and later kernels have the entry point at 0x00000000.
5352 So a typical call to build a U-Boot image would read:
5354 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5355 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5356 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5357 > examples/uImage.TQM850L
5358 Image Name: 2.4.4 kernel for TQM850L
5359 Created: Wed Jul 19 02:34:59 2000
5360 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5361 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5362 Load Address: 0x00000000
5363 Entry Point: 0x00000000
5365 To verify the contents of the image (or check for corruption):
5367 -> tools/mkimage -l examples/uImage.TQM850L
5368 Image Name: 2.4.4 kernel for TQM850L
5369 Created: Wed Jul 19 02:34:59 2000
5370 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5371 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5372 Load Address: 0x00000000
5373 Entry Point: 0x00000000
5375 NOTE: for embedded systems where boot time is critical you can trade
5376 speed for memory and install an UNCOMPRESSED image instead: this
5377 needs more space in Flash, but boots much faster since it does not
5378 need to be uncompressed:
5380 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5381 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5382 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5383 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5384 > examples/uImage.TQM850L-uncompressed
5385 Image Name: 2.4.4 kernel for TQM850L
5386 Created: Wed Jul 19 02:34:59 2000
5387 Image Type: PowerPC Linux Kernel Image (uncompressed)
5388 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5389 Load Address: 0x00000000
5390 Entry Point: 0x00000000
5393 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5394 when your kernel is intended to use an initial ramdisk:
5396 -> tools/mkimage -n 'Simple Ramdisk Image' \
5397 > -A ppc -O linux -T ramdisk -C gzip \
5398 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5399 Image Name: Simple Ramdisk Image
5400 Created: Wed Jan 12 14:01:50 2000
5401 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5402 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5403 Load Address: 0x00000000
5404 Entry Point: 0x00000000
5406 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5407 option performs the converse operation of the mkimage's second form (the "-d"
5408 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5411 tools/dumpimage -i image -T type -p position data_file
5412 -i ==> extract from the 'image' a specific 'data_file'
5413 -T ==> set image type to 'type'
5414 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5417 Installing a Linux Image:
5418 -------------------------
5420 To downloading a U-Boot image over the serial (console) interface,
5421 you must convert the image to S-Record format:
5423 objcopy -I binary -O srec examples/image examples/image.srec
5425 The 'objcopy' does not understand the information in the U-Boot
5426 image header, so the resulting S-Record file will be relative to
5427 address 0x00000000. To load it to a given address, you need to
5428 specify the target address as 'offset' parameter with the 'loads'
5431 Example: install the image to address 0x40100000 (which on the
5432 TQM8xxL is in the first Flash bank):
5434 => erase 40100000 401FFFFF
5440 ## Ready for S-Record download ...
5441 ~>examples/image.srec
5442 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5444 15989 15990 15991 15992
5445 [file transfer complete]
5447 ## Start Addr = 0x00000000
5450 You can check the success of the download using the 'iminfo' command;
5451 this includes a checksum verification so you can be sure no data
5452 corruption happened:
5456 ## Checking Image at 40100000 ...
5457 Image Name: 2.2.13 for initrd on TQM850L
5458 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5459 Data Size: 335725 Bytes = 327 kB = 0 MB
5460 Load Address: 00000000
5461 Entry Point: 0000000c
5462 Verifying Checksum ... OK
5468 The "bootm" command is used to boot an application that is stored in
5469 memory (RAM or Flash). In case of a Linux kernel image, the contents
5470 of the "bootargs" environment variable is passed to the kernel as
5471 parameters. You can check and modify this variable using the
5472 "printenv" and "setenv" commands:
5475 => printenv bootargs
5476 bootargs=root=/dev/ram
5478 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5480 => printenv bootargs
5481 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5484 ## Booting Linux kernel at 40020000 ...
5485 Image Name: 2.2.13 for NFS on TQM850L
5486 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5487 Data Size: 381681 Bytes = 372 kB = 0 MB
5488 Load Address: 00000000
5489 Entry Point: 0000000c
5490 Verifying Checksum ... OK
5491 Uncompressing Kernel Image ... OK
5492 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
5493 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5494 time_init: decrementer frequency = 187500000/60
5495 Calibrating delay loop... 49.77 BogoMIPS
5496 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5499 If you want to boot a Linux kernel with initial RAM disk, you pass
5500 the memory addresses of both the kernel and the initrd image (PPBCOOT
5501 format!) to the "bootm" command:
5503 => imi 40100000 40200000
5505 ## Checking Image at 40100000 ...
5506 Image Name: 2.2.13 for initrd on TQM850L
5507 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5508 Data Size: 335725 Bytes = 327 kB = 0 MB
5509 Load Address: 00000000
5510 Entry Point: 0000000c
5511 Verifying Checksum ... OK
5513 ## Checking Image at 40200000 ...
5514 Image Name: Simple Ramdisk Image
5515 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5516 Data Size: 566530 Bytes = 553 kB = 0 MB
5517 Load Address: 00000000
5518 Entry Point: 00000000
5519 Verifying Checksum ... OK
5521 => bootm 40100000 40200000
5522 ## Booting Linux kernel at 40100000 ...
5523 Image Name: 2.2.13 for initrd on TQM850L
5524 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5525 Data Size: 335725 Bytes = 327 kB = 0 MB
5526 Load Address: 00000000
5527 Entry Point: 0000000c
5528 Verifying Checksum ... OK
5529 Uncompressing Kernel Image ... OK
5530 ## Loading RAMDisk Image at 40200000 ...
5531 Image Name: Simple Ramdisk Image
5532 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5533 Data Size: 566530 Bytes = 553 kB = 0 MB
5534 Load Address: 00000000
5535 Entry Point: 00000000
5536 Verifying Checksum ... OK
5537 Loading Ramdisk ... OK
5538 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
5539 Boot arguments: root=/dev/ram
5540 time_init: decrementer frequency = 187500000/60
5541 Calibrating delay loop... 49.77 BogoMIPS
5543 RAMDISK: Compressed image found at block 0
5544 VFS: Mounted root (ext2 filesystem).
5548 Boot Linux and pass a flat device tree:
5551 First, U-Boot must be compiled with the appropriate defines. See the section
5552 titled "Linux Kernel Interface" above for a more in depth explanation. The
5553 following is an example of how to start a kernel and pass an updated
5559 oft=oftrees/mpc8540ads.dtb
5560 => tftp $oftaddr $oft
5561 Speed: 1000, full duplex
5563 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5564 Filename 'oftrees/mpc8540ads.dtb'.
5565 Load address: 0x300000
5568 Bytes transferred = 4106 (100a hex)
5569 => tftp $loadaddr $bootfile
5570 Speed: 1000, full duplex
5572 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5574 Load address: 0x200000
5575 Loading:############
5577 Bytes transferred = 1029407 (fb51f hex)
5582 => bootm $loadaddr - $oftaddr
5583 ## Booting image at 00200000 ...
5584 Image Name: Linux-2.6.17-dirty
5585 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5586 Data Size: 1029343 Bytes = 1005.2 kB
5587 Load Address: 00000000
5588 Entry Point: 00000000
5589 Verifying Checksum ... OK
5590 Uncompressing Kernel Image ... OK
5591 Booting using flat device tree at 0x300000
5592 Using MPC85xx ADS machine description
5593 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5597 More About U-Boot Image Types:
5598 ------------------------------
5600 U-Boot supports the following image types:
5602 "Standalone Programs" are directly runnable in the environment
5603 provided by U-Boot; it is expected that (if they behave
5604 well) you can continue to work in U-Boot after return from
5605 the Standalone Program.
5606 "OS Kernel Images" are usually images of some Embedded OS which
5607 will take over control completely. Usually these programs
5608 will install their own set of exception handlers, device
5609 drivers, set up the MMU, etc. - this means, that you cannot
5610 expect to re-enter U-Boot except by resetting the CPU.
5611 "RAMDisk Images" are more or less just data blocks, and their
5612 parameters (address, size) are passed to an OS kernel that is
5614 "Multi-File Images" contain several images, typically an OS
5615 (Linux) kernel image and one or more data images like
5616 RAMDisks. This construct is useful for instance when you want
5617 to boot over the network using BOOTP etc., where the boot
5618 server provides just a single image file, but you want to get
5619 for instance an OS kernel and a RAMDisk image.
5621 "Multi-File Images" start with a list of image sizes, each
5622 image size (in bytes) specified by an "uint32_t" in network
5623 byte order. This list is terminated by an "(uint32_t)0".
5624 Immediately after the terminating 0 follow the images, one by
5625 one, all aligned on "uint32_t" boundaries (size rounded up to
5626 a multiple of 4 bytes).
5628 "Firmware Images" are binary images containing firmware (like
5629 U-Boot or FPGA images) which usually will be programmed to
5632 "Script files" are command sequences that will be executed by
5633 U-Boot's command interpreter; this feature is especially
5634 useful when you configure U-Boot to use a real shell (hush)
5635 as command interpreter.
5637 Booting the Linux zImage:
5638 -------------------------
5640 On some platforms, it's possible to boot Linux zImage. This is done
5641 using the "bootz" command. The syntax of "bootz" command is the same
5642 as the syntax of "bootm" command.
5644 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5645 kernel with raw initrd images. The syntax is slightly different, the
5646 address of the initrd must be augmented by it's size, in the following
5647 format: "<initrd addres>:<initrd size>".
5653 One of the features of U-Boot is that you can dynamically load and
5654 run "standalone" applications, which can use some resources of
5655 U-Boot like console I/O functions or interrupt services.
5657 Two simple examples are included with the sources:
5662 'examples/hello_world.c' contains a small "Hello World" Demo
5663 application; it is automatically compiled when you build U-Boot.
5664 It's configured to run at address 0x00040004, so you can play with it
5668 ## Ready for S-Record download ...
5669 ~>examples/hello_world.srec
5670 1 2 3 4 5 6 7 8 9 10 11 ...
5671 [file transfer complete]
5673 ## Start Addr = 0x00040004
5675 => go 40004 Hello World! This is a test.
5676 ## Starting application at 0x00040004 ...
5687 Hit any key to exit ...
5689 ## Application terminated, rc = 0x0
5691 Another example, which demonstrates how to register a CPM interrupt
5692 handler with the U-Boot code, can be found in 'examples/timer.c'.
5693 Here, a CPM timer is set up to generate an interrupt every second.
5694 The interrupt service routine is trivial, just printing a '.'
5695 character, but this is just a demo program. The application can be
5696 controlled by the following keys:
5698 ? - print current values og the CPM Timer registers
5699 b - enable interrupts and start timer
5700 e - stop timer and disable interrupts
5701 q - quit application
5704 ## Ready for S-Record download ...
5705 ~>examples/timer.srec
5706 1 2 3 4 5 6 7 8 9 10 11 ...
5707 [file transfer complete]
5709 ## Start Addr = 0x00040004
5712 ## Starting application at 0x00040004 ...
5715 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5718 [q, b, e, ?] Set interval 1000000 us
5721 [q, b, e, ?] ........
5722 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5725 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5728 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5731 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5733 [q, b, e, ?] ...Stopping timer
5735 [q, b, e, ?] ## Application terminated, rc = 0x0
5741 Over time, many people have reported problems when trying to use the
5742 "minicom" terminal emulation program for serial download. I (wd)
5743 consider minicom to be broken, and recommend not to use it. Under
5744 Unix, I recommend to use C-Kermit for general purpose use (and
5745 especially for kermit binary protocol download ("loadb" command), and
5746 use "cu" for S-Record download ("loads" command). See
5747 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5748 for help with kermit.
5751 Nevertheless, if you absolutely want to use it try adding this
5752 configuration to your "File transfer protocols" section:
5754 Name Program Name U/D FullScr IO-Red. Multi
5755 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5756 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5762 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5763 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5765 Building requires a cross environment; it is known to work on
5766 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5767 need gmake since the Makefiles are not compatible with BSD make).
5768 Note that the cross-powerpc package does not install include files;
5769 attempting to build U-Boot will fail because <machine/ansi.h> is
5770 missing. This file has to be installed and patched manually:
5772 # cd /usr/pkg/cross/powerpc-netbsd/include
5774 # ln -s powerpc machine
5775 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5776 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5778 Native builds *don't* work due to incompatibilities between native
5779 and U-Boot include files.
5781 Booting assumes that (the first part of) the image booted is a
5782 stage-2 loader which in turn loads and then invokes the kernel
5783 proper. Loader sources will eventually appear in the NetBSD source
5784 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5785 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5788 Implementation Internals:
5789 =========================
5791 The following is not intended to be a complete description of every
5792 implementation detail. However, it should help to understand the
5793 inner workings of U-Boot and make it easier to port it to custom
5797 Initial Stack, Global Data:
5798 ---------------------------
5800 The implementation of U-Boot is complicated by the fact that U-Boot
5801 starts running out of ROM (flash memory), usually without access to
5802 system RAM (because the memory controller is not initialized yet).
5803 This means that we don't have writable Data or BSS segments, and BSS
5804 is not initialized as zero. To be able to get a C environment working
5805 at all, we have to allocate at least a minimal stack. Implementation
5806 options for this are defined and restricted by the CPU used: Some CPU
5807 models provide on-chip memory (like the IMMR area on MPC8xx and
5808 MPC826x processors), on others (parts of) the data cache can be
5809 locked as (mis-) used as memory, etc.
5811 Chris Hallinan posted a good summary of these issues to the
5812 U-Boot mailing list:
5814 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5815 From: "Chris Hallinan" <clh@net1plus.com>
5816 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5819 Correct me if I'm wrong, folks, but the way I understand it
5820 is this: Using DCACHE as initial RAM for Stack, etc, does not
5821 require any physical RAM backing up the cache. The cleverness
5822 is that the cache is being used as a temporary supply of
5823 necessary storage before the SDRAM controller is setup. It's
5824 beyond the scope of this list to explain the details, but you
5825 can see how this works by studying the cache architecture and
5826 operation in the architecture and processor-specific manuals.
5828 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5829 is another option for the system designer to use as an
5830 initial stack/RAM area prior to SDRAM being available. Either
5831 option should work for you. Using CS 4 should be fine if your
5832 board designers haven't used it for something that would
5833 cause you grief during the initial boot! It is frequently not
5836 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5837 with your processor/board/system design. The default value
5838 you will find in any recent u-boot distribution in
5839 walnut.h should work for you. I'd set it to a value larger
5840 than your SDRAM module. If you have a 64MB SDRAM module, set
5841 it above 400_0000. Just make sure your board has no resources
5842 that are supposed to respond to that address! That code in
5843 start.S has been around a while and should work as is when
5844 you get the config right.
5849 It is essential to remember this, since it has some impact on the C
5850 code for the initialization procedures:
5852 * Initialized global data (data segment) is read-only. Do not attempt
5855 * Do not use any uninitialized global data (or implicitly initialized
5856 as zero data - BSS segment) at all - this is undefined, initiali-
5857 zation is performed later (when relocating to RAM).
5859 * Stack space is very limited. Avoid big data buffers or things like
5862 Having only the stack as writable memory limits means we cannot use
5863 normal global data to share information between the code. But it
5864 turned out that the implementation of U-Boot can be greatly
5865 simplified by making a global data structure (gd_t) available to all
5866 functions. We could pass a pointer to this data as argument to _all_
5867 functions, but this would bloat the code. Instead we use a feature of
5868 the GCC compiler (Global Register Variables) to share the data: we
5869 place a pointer (gd) to the global data into a register which we
5870 reserve for this purpose.
5872 When choosing a register for such a purpose we are restricted by the
5873 relevant (E)ABI specifications for the current architecture, and by
5874 GCC's implementation.
5876 For PowerPC, the following registers have specific use:
5878 R2: reserved for system use
5879 R3-R4: parameter passing and return values
5880 R5-R10: parameter passing
5881 R13: small data area pointer
5885 (U-Boot also uses R12 as internal GOT pointer. r12
5886 is a volatile register so r12 needs to be reset when
5887 going back and forth between asm and C)
5889 ==> U-Boot will use R2 to hold a pointer to the global data
5891 Note: on PPC, we could use a static initializer (since the
5892 address of the global data structure is known at compile time),
5893 but it turned out that reserving a register results in somewhat
5894 smaller code - although the code savings are not that big (on
5895 average for all boards 752 bytes for the whole U-Boot image,
5896 624 text + 127 data).
5898 On ARM, the following registers are used:
5900 R0: function argument word/integer result
5901 R1-R3: function argument word
5902 R9: platform specific
5903 R10: stack limit (used only if stack checking is enabled)
5904 R11: argument (frame) pointer
5905 R12: temporary workspace
5908 R15: program counter
5910 ==> U-Boot will use R9 to hold a pointer to the global data
5912 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5914 On Nios II, the ABI is documented here:
5915 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5917 ==> U-Boot will use gp to hold a pointer to the global data
5919 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5920 to access small data sections, so gp is free.
5922 On NDS32, the following registers are used:
5924 R0-R1: argument/return
5926 R15: temporary register for assembler
5927 R16: trampoline register
5928 R28: frame pointer (FP)
5929 R29: global pointer (GP)
5930 R30: link register (LP)
5931 R31: stack pointer (SP)
5932 PC: program counter (PC)
5934 ==> U-Boot will use R10 to hold a pointer to the global data
5936 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5937 or current versions of GCC may "optimize" the code too much.
5942 U-Boot runs in system state and uses physical addresses, i.e. the
5943 MMU is not used either for address mapping nor for memory protection.
5945 The available memory is mapped to fixed addresses using the memory
5946 controller. In this process, a contiguous block is formed for each
5947 memory type (Flash, SDRAM, SRAM), even when it consists of several
5948 physical memory banks.
5950 U-Boot is installed in the first 128 kB of the first Flash bank (on
5951 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5952 booting and sizing and initializing DRAM, the code relocates itself
5953 to the upper end of DRAM. Immediately below the U-Boot code some
5954 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5955 configuration setting]. Below that, a structure with global Board
5956 Info data is placed, followed by the stack (growing downward).
5958 Additionally, some exception handler code is copied to the low 8 kB
5959 of DRAM (0x00000000 ... 0x00001FFF).
5961 So a typical memory configuration with 16 MB of DRAM could look like
5964 0x0000 0000 Exception Vector code
5967 0x0000 2000 Free for Application Use
5973 0x00FB FF20 Monitor Stack (Growing downward)
5974 0x00FB FFAC Board Info Data and permanent copy of global data
5975 0x00FC 0000 Malloc Arena
5978 0x00FE 0000 RAM Copy of Monitor Code
5979 ... eventually: LCD or video framebuffer
5980 ... eventually: pRAM (Protected RAM - unchanged by reset)
5981 0x00FF FFFF [End of RAM]
5984 System Initialization:
5985 ----------------------
5987 In the reset configuration, U-Boot starts at the reset entry point
5988 (on most PowerPC systems at address 0x00000100). Because of the reset
5989 configuration for CS0# this is a mirror of the on board Flash memory.
5990 To be able to re-map memory U-Boot then jumps to its link address.
5991 To be able to implement the initialization code in C, a (small!)
5992 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5993 which provide such a feature like MPC8xx or MPC8260), or in a locked
5994 part of the data cache. After that, U-Boot initializes the CPU core,
5995 the caches and the SIU.
5997 Next, all (potentially) available memory banks are mapped using a
5998 preliminary mapping. For example, we put them on 512 MB boundaries
5999 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6000 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6001 programmed for SDRAM access. Using the temporary configuration, a
6002 simple memory test is run that determines the size of the SDRAM
6005 When there is more than one SDRAM bank, and the banks are of
6006 different size, the largest is mapped first. For equal size, the first
6007 bank (CS2#) is mapped first. The first mapping is always for address
6008 0x00000000, with any additional banks following immediately to create
6009 contiguous memory starting from 0.
6011 Then, the monitor installs itself at the upper end of the SDRAM area
6012 and allocates memory for use by malloc() and for the global Board
6013 Info data; also, the exception vector code is copied to the low RAM
6014 pages, and the final stack is set up.
6016 Only after this relocation will you have a "normal" C environment;
6017 until that you are restricted in several ways, mostly because you are
6018 running from ROM, and because the code will have to be relocated to a
6022 U-Boot Porting Guide:
6023 ----------------------
6025 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6029 int main(int argc, char *argv[])
6031 sighandler_t no_more_time;
6033 signal(SIGALRM, no_more_time);
6034 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6036 if (available_money > available_manpower) {
6037 Pay consultant to port U-Boot;
6041 Download latest U-Boot source;
6043 Subscribe to u-boot mailing list;
6046 email("Hi, I am new to U-Boot, how do I get started?");
6049 Read the README file in the top level directory;
6050 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6051 Read applicable doc/*.README;
6052 Read the source, Luke;
6053 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6056 if (available_money > toLocalCurrency ($2500))
6059 Add a lot of aggravation and time;
6061 if (a similar board exists) { /* hopefully... */
6062 cp -a board/<similar> board/<myboard>
6063 cp include/configs/<similar>.h include/configs/<myboard>.h
6065 Create your own board support subdirectory;
6066 Create your own board include/configs/<myboard>.h file;
6068 Edit new board/<myboard> files
6069 Edit new include/configs/<myboard>.h
6074 Add / modify source code;
6078 email("Hi, I am having problems...");
6080 Send patch file to the U-Boot email list;
6081 if (reasonable critiques)
6082 Incorporate improvements from email list code review;
6084 Defend code as written;
6090 void no_more_time (int sig)
6099 All contributions to U-Boot should conform to the Linux kernel
6100 coding style; see the file "Documentation/CodingStyle" and the script
6101 "scripts/Lindent" in your Linux kernel source directory.
6103 Source files originating from a different project (for example the
6104 MTD subsystem) are generally exempt from these guidelines and are not
6105 reformatted to ease subsequent migration to newer versions of those
6108 Please note that U-Boot is implemented in C (and to some small parts in
6109 Assembler); no C++ is used, so please do not use C++ style comments (//)
6112 Please also stick to the following formatting rules:
6113 - remove any trailing white space
6114 - use TAB characters for indentation and vertical alignment, not spaces
6115 - make sure NOT to use DOS '\r\n' line feeds
6116 - do not add more than 2 consecutive empty lines to source files
6117 - do not add trailing empty lines to source files
6119 Submissions which do not conform to the standards may be returned
6120 with a request to reformat the changes.
6126 Since the number of patches for U-Boot is growing, we need to
6127 establish some rules. Submissions which do not conform to these rules
6128 may be rejected, even when they contain important and valuable stuff.
6130 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6132 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6133 see http://lists.denx.de/mailman/listinfo/u-boot
6135 When you send a patch, please include the following information with
6138 * For bug fixes: a description of the bug and how your patch fixes
6139 this bug. Please try to include a way of demonstrating that the
6140 patch actually fixes something.
6142 * For new features: a description of the feature and your
6145 * A CHANGELOG entry as plaintext (separate from the patch)
6147 * For major contributions, add a MAINTAINERS file with your
6148 information and associated file and directory references.
6150 * When you add support for a new board, don't forget to add a
6151 maintainer e-mail address to the boards.cfg file, too.
6153 * If your patch adds new configuration options, don't forget to
6154 document these in the README file.
6156 * The patch itself. If you are using git (which is *strongly*
6157 recommended) you can easily generate the patch using the
6158 "git format-patch". If you then use "git send-email" to send it to
6159 the U-Boot mailing list, you will avoid most of the common problems
6160 with some other mail clients.
6162 If you cannot use git, use "diff -purN OLD NEW". If your version of
6163 diff does not support these options, then get the latest version of
6166 The current directory when running this command shall be the parent
6167 directory of the U-Boot source tree (i. e. please make sure that
6168 your patch includes sufficient directory information for the
6171 We prefer patches as plain text. MIME attachments are discouraged,
6172 and compressed attachments must not be used.
6174 * If one logical set of modifications affects or creates several
6175 files, all these changes shall be submitted in a SINGLE patch file.
6177 * Changesets that contain different, unrelated modifications shall be
6178 submitted as SEPARATE patches, one patch per changeset.
6183 * Before sending the patch, run the buildman script on your patched
6184 source tree and make sure that no errors or warnings are reported
6185 for any of the boards.
6187 * Keep your modifications to the necessary minimum: A patch
6188 containing several unrelated changes or arbitrary reformats will be
6189 returned with a request to re-formatting / split it.
6191 * If you modify existing code, make sure that your new code does not
6192 add to the memory footprint of the code ;-) Small is beautiful!
6193 When adding new features, these should compile conditionally only
6194 (using #ifdef), and the resulting code with the new feature
6195 disabled must not need more memory than the old code without your
6198 * Remember that there is a size limit of 100 kB per message on the
6199 u-boot mailing list. Bigger patches will be moderated. If they are
6200 reasonable and not too big, they will be acknowledged. But patches
6201 bigger than the size limit should be avoided.
git.openpandora.org / pandora-u-boot.git / blob