README

		This enables the RSA algorithm used for FIT image verification
		in U-Boot. See doc/uImage.FIT/signature.txt for more information.

		The signing part is build into mkimage regardless of this
		option.

- bootcount support:
		CONFIG_BOOTCOUNT_LIMIT

		This enables the bootcounter support, see:
		http://www.denx.de/wiki/DULG/UBootBootCountLimit

		CONFIG_AT91SAM9XE
		enable special bootcounter support on at91sam9xe based boards.
		CONFIG_BLACKFIN
		enable special bootcounter support on blackfin based boards.
		CONFIG_SOC_DA8XX
		enable special bootcounter support on da850 based boards.
		CONFIG_BOOTCOUNT_RAM
		enable support for the bootcounter in RAM
		CONFIG_BOOTCOUNT_I2C
		enable support for the bootcounter on an i2c (like RTC) device.
			CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
			CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
						    the bootcounter.
			CONFIG_BOOTCOUNT_ALEN = address len

- Show boot progress:
		CONFIG_SHOW_BOOT_PROGRESS

		Defining this option allows to add some board-
		specific code (calling a user-provided function
		"show_boot_progress(int)") that enables you to show
		the system's boot progress on some display (for
		example, some LED's) on your board. At the moment,
		the following checkpoints are implemented:

- Detailed boot stage timing
		CONFIG_BOOTSTAGE
		Define this option to get detailed timing of each stage
		of the boot process.

		CONFIG_BOOTSTAGE_USER_COUNT
		This is the number of available user bootstage records.
		Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
		a new ID will be allocated from this stash. If you exceed
		the limit, recording will stop.

		CONFIG_BOOTSTAGE_REPORT
		Define this to print a report before boot, similar to this:

		Timer summary in microseconds:
		       Mark    Elapsed  Stage
			  0          0  reset
		  3,575,678  3,575,678  board_init_f start
		  3,575,695         17  arch_cpu_init A9
		  3,575,777         82  arch_cpu_init done
		  3,659,598     83,821  board_init_r start
		  3,910,375    250,777  main_loop
		 29,916,167 26,005,792  bootm_start
		 30,361,327    445,160  start_kernel

		CONFIG_CMD_BOOTSTAGE
		Add a 'bootstage' command which supports printing a report
		and un/stashing of bootstage data.

		CONFIG_BOOTSTAGE_FDT
		Stash the bootstage information in the FDT. A root 'bootstage'
		node is created with each bootstage id as a child. Each child
		has a 'name' property and either 'mark' containing the
		mark time in microsecond, or 'accum' containing the
		accumulated time for that bootstage id in microseconds.
		For example:

		bootstage {
			154 {
				name = "board_init_f";
				mark = <3575678>;
			};
			170 {
				name = "lcd";
				accum = <33482>;
			};
		};

		Code in the Linux kernel can find this in /proc/devicetree.

Legacy uImage format:

  Arg	Where			When
    1	common/cmd_bootm.c	before attempting to boot an image
   -1	common/cmd_bootm.c	Image header has bad	 magic number
    2	common/cmd_bootm.c	Image header has correct magic number
   -2	common/cmd_bootm.c	Image header has bad	 checksum
    3	common/cmd_bootm.c	Image header has correct checksum
   -3	common/cmd_bootm.c	Image data   has bad	 checksum
    4	common/cmd_bootm.c	Image data   has correct checksum
   -4	common/cmd_bootm.c	Image is for unsupported architecture
    5	common/cmd_bootm.c	Architecture check OK
   -5	common/cmd_bootm.c	Wrong Image Type (not kernel, multi)
    6	common/cmd_bootm.c	Image Type check OK
   -6	common/cmd_bootm.c	gunzip uncompression error
   -7	common/cmd_bootm.c	Unimplemented compression type
    7	common/cmd_bootm.c	Uncompression OK
    8	common/cmd_bootm.c	No uncompress/copy overwrite error
   -9	common/cmd_bootm.c	Unsupported OS (not Linux, BSD, VxWorks, QNX)

    9	common/image.c		Start initial ramdisk verification
  -10	common/image.c		Ramdisk header has bad	   magic number
  -11	common/image.c		Ramdisk header has bad	   checksum
   10	common/image.c		Ramdisk header is OK
  -12	common/image.c		Ramdisk data   has bad	   checksum
   11	common/image.c		Ramdisk data   has correct checksum
   12	common/image.c		Ramdisk verification complete, start loading
  -13	common/image.c		Wrong Image Type (not PPC Linux ramdisk)
   13	common/image.c		Start multifile image verification
   14	common/image.c		No initial ramdisk, no multifile, continue.

   15	arch/<arch>/lib/bootm.c All preparation done, transferring control to OS

  -30	arch/powerpc/lib/board.c	Fatal error, hang the system
  -31	post/post.c		POST test failed, detected by post_output_backlog()
  -32	post/post.c		POST test failed, detected by post_run_single()

   34	common/cmd_doc.c	before loading a Image from a DOC device
  -35	common/cmd_doc.c	Bad usage of "doc" command
   35	common/cmd_doc.c	correct usage of "doc" command
  -36	common/cmd_doc.c	No boot device
   36	common/cmd_doc.c	correct boot device
  -37	common/cmd_doc.c	Unknown Chip ID on boot device
   37	common/cmd_doc.c	correct chip ID found, device available
  -38	common/cmd_doc.c	Read Error on boot device
   38	common/cmd_doc.c	reading Image header from DOC device OK
  -39	common/cmd_doc.c	Image header has bad magic number
   39	common/cmd_doc.c	Image header has correct magic number
  -40	common/cmd_doc.c	Error reading Image from DOC device
   40	common/cmd_doc.c	Image header has correct magic number
   41	common/cmd_ide.c	before loading a Image from a IDE device
  -42	common/cmd_ide.c	Bad usage of "ide" command
   42	common/cmd_ide.c	correct usage of "ide" command
  -43	common/cmd_ide.c	No boot device
   43	common/cmd_ide.c	boot device found
  -44	common/cmd_ide.c	Device not available
   44	common/cmd_ide.c	Device available
  -45	common/cmd_ide.c	wrong partition selected
   45	common/cmd_ide.c	partition selected
  -46	common/cmd_ide.c	Unknown partition table
   46	common/cmd_ide.c	valid partition table found
  -47	common/cmd_ide.c	Invalid partition type
   47	common/cmd_ide.c	correct partition type
  -48	common/cmd_ide.c	Error reading Image Header on boot device
   48	common/cmd_ide.c	reading Image Header from IDE device OK
  -49	common/cmd_ide.c	Image header has bad magic number
   49	common/cmd_ide.c	Image header has correct magic number
  -50	common/cmd_ide.c	Image header has bad	 checksum
   50	common/cmd_ide.c	Image header has correct checksum
  -51	common/cmd_ide.c	Error reading Image from IDE device
   51	common/cmd_ide.c	reading Image from IDE device OK
   52	common/cmd_nand.c	before loading a Image from a NAND device
  -53	common/cmd_nand.c	Bad usage of "nand" command
   53	common/cmd_nand.c	correct usage of "nand" command
  -54	common/cmd_nand.c	No boot device
   54	common/cmd_nand.c	boot device found
  -55	common/cmd_nand.c	Unknown Chip ID on boot device
   55	common/cmd_nand.c	correct chip ID found, device available
  -56	common/cmd_nand.c	Error reading Image Header on boot device
   56	common/cmd_nand.c	reading Image Header from NAND device OK
  -57	common/cmd_nand.c	Image header has bad magic number
   57	common/cmd_nand.c	Image header has correct magic number
  -58	common/cmd_nand.c	Error reading Image from NAND device
   58	common/cmd_nand.c	reading Image from NAND device OK

  -60	common/env_common.c	Environment has a bad CRC, using default

   64	net/eth.c		starting with Ethernet configuration.
  -64	net/eth.c		no Ethernet found.
   65	net/eth.c		Ethernet found.

  -80	common/cmd_net.c	usage wrong
   80	common/cmd_net.c	before calling NetLoop()
  -81	common/cmd_net.c	some error in NetLoop() occurred
   81	common/cmd_net.c	NetLoop() back without error
  -82	common/cmd_net.c	size == 0 (File with size 0 loaded)
   82	common/cmd_net.c	trying automatic boot
   83	common/cmd_net.c	running "source" command
  -83	common/cmd_net.c	some error in automatic boot or "source" command
   84	common/cmd_net.c	end without errors

FIT uImage format:

  Arg	Where			When
  100	common/cmd_bootm.c	Kernel FIT Image has correct format
 -100	common/cmd_bootm.c	Kernel FIT Image has incorrect format
  101	common/cmd_bootm.c	No Kernel subimage unit name, using configuration
 -101	common/cmd_bootm.c	Can't get configuration for kernel subimage
  102	common/cmd_bootm.c	Kernel unit name specified
 -103	common/cmd_bootm.c	Can't get kernel subimage node offset
  103	common/cmd_bootm.c	Found configuration node
  104	common/cmd_bootm.c	Got kernel subimage node offset
 -104	common/cmd_bootm.c	Kernel subimage hash verification failed
  105	common/cmd_bootm.c	Kernel subimage hash verification OK
 -105	common/cmd_bootm.c	Kernel subimage is for unsupported architecture
  106	common/cmd_bootm.c	Architecture check OK
 -106	common/cmd_bootm.c	Kernel subimage has wrong type
  107	common/cmd_bootm.c	Kernel subimage type OK
 -107	common/cmd_bootm.c	Can't get kernel subimage data/size
  108	common/cmd_bootm.c	Got kernel subimage data/size
 -108	common/cmd_bootm.c	Wrong image type (not legacy, FIT)
 -109	common/cmd_bootm.c	Can't get kernel subimage type
 -110	common/cmd_bootm.c	Can't get kernel subimage comp
 -111	common/cmd_bootm.c	Can't get kernel subimage os
 -112	common/cmd_bootm.c	Can't get kernel subimage load address
 -113	common/cmd_bootm.c	Image uncompress/copy overwrite error

  120	common/image.c		Start initial ramdisk verification
 -120	common/image.c		Ramdisk FIT image has incorrect format
  121	common/image.c		Ramdisk FIT image has correct format
  122	common/image.c		No ramdisk subimage unit name, using configuration
 -122	common/image.c		Can't get configuration for ramdisk subimage
  123	common/image.c		Ramdisk unit name specified
 -124	common/image.c		Can't get ramdisk subimage node offset
  125	common/image.c		Got ramdisk subimage node offset
 -125	common/image.c		Ramdisk subimage hash verification failed
  126	common/image.c		Ramdisk subimage hash verification OK
 -126	common/image.c		Ramdisk subimage for unsupported architecture
  127	common/image.c		Architecture check OK
 -127	common/image.c		Can't get ramdisk subimage data/size
  128	common/image.c		Got ramdisk subimage data/size
  129	common/image.c		Can't get ramdisk load address
 -129	common/image.c		Got ramdisk load address

 -130	common/cmd_doc.c	Incorrect FIT image format
  131	common/cmd_doc.c	FIT image format OK

 -140	common/cmd_ide.c	Incorrect FIT image format
  141	common/cmd_ide.c	FIT image format OK

 -150	common/cmd_nand.c	Incorrect FIT image format
  151	common/cmd_nand.c	FIT image format OK

- legacy image format:
		CONFIG_IMAGE_FORMAT_LEGACY
		enables the legacy image format support in U-Boot.

		Default:
		enabled if CONFIG_FIT_SIGNATURE is not defined.

		CONFIG_DISABLE_IMAGE_LEGACY
		disable the legacy image format

		This define is introduced, as the legacy image format is
		enabled per default for backward compatibility.

- FIT image support:
		CONFIG_FIT
		Enable support for the FIT uImage format.

		CONFIG_FIT_BEST_MATCH
		When no configuration is explicitly selected, default to the
		one whose fdt's compatibility field best matches that of
		U-Boot itself. A match is considered "best" if it matches the
		most specific compatibility entry of U-Boot's fdt's root node.
		The order of entries in the configuration's fdt is ignored.

		CONFIG_FIT_SIGNATURE
		This option enables signature verification of FIT uImages,
		using a hash signed and verified using RSA. See
		doc/uImage.FIT/signature.txt for more details.

		WARNING: When relying on signed FIT images with required
		signature check the legacy image format is default
		disabled. If a board need legacy image format support
		enable this through CONFIG_IMAGE_FORMAT_LEGACY

		CONFIG_FIT_DISABLE_SHA256
		Supporting SHA256 hashes has quite an impact on binary size.
		For constrained systems sha256 hash support can be disabled
		with this option.

- Standalone program support:
		CONFIG_STANDALONE_LOAD_ADDR

		This option defines a board specific value for the
		address where standalone program gets loaded, thus
		overwriting the architecture dependent default
		settings.

- Frame Buffer Address:
		CONFIG_FB_ADDR

		Define CONFIG_FB_ADDR if you want to use specific
		address for frame buffer.  This is typically the case
		when using a graphics controller has separate video
		memory.  U-Boot will then place the frame buffer at
		the given address instead of dynamically reserving it
		in system RAM by calling lcd_setmem(), which grabs
		the memory for the frame buffer depending on the
		configured panel size.

		Please see board_init_f function.

- Automatic software updates via TFTP server
		CONFIG_UPDATE_TFTP
		CONFIG_UPDATE_TFTP_CNT_MAX
		CONFIG_UPDATE_TFTP_MSEC_MAX

		These options enable and control the auto-update feature;
		for a more detailed description refer to doc/README.update.

- MTD Support (mtdparts command, UBI support)
		CONFIG_MTD_DEVICE

		Adds the MTD device infrastructure from the Linux kernel.
		Needed for mtdparts command support.

		CONFIG_MTD_PARTITIONS

		Adds the MTD partitioning infrastructure from the Linux
		kernel. Needed for UBI support.

- UBI support
		CONFIG_CMD_UBI

		Adds commands for interacting with MTD partitions formatted
		with the UBI flash translation layer

		Requires also defining CONFIG_RBTREE

		CONFIG_UBI_SILENCE_MSG

		Make the verbose messages from UBI stop printing.  This leaves
		warnings and errors enabled.

- UBIFS support
		CONFIG_CMD_UBIFS

		Adds commands for interacting with UBI volumes formatted as
		UBIFS.  UBIFS is read-only in u-boot.

		Requires UBI support as well as CONFIG_LZO

		CONFIG_UBIFS_SILENCE_MSG

		Make the verbose messages from UBIFS stop printing.  This leaves
		warnings and errors enabled.

- SPL framework
		CONFIG_SPL
		Enable building of SPL globally.

		CONFIG_SPL_LDSCRIPT
		LDSCRIPT for linking the SPL binary.

		CONFIG_SPL_MAX_FOOTPRINT
		Maximum size in memory allocated to the SPL, BSS included.
		When defined, the linker checks that the actual memory
		used by SPL from _start to __bss_end does not exceed it.
		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
		must not be both defined at the same time.

		CONFIG_SPL_MAX_SIZE
		Maximum size of the SPL image (text, data, rodata, and
		linker lists sections), BSS excluded.
		When defined, the linker checks that the actual size does
		not exceed it.

		CONFIG_SPL_TEXT_BASE
		TEXT_BASE for linking the SPL binary.

		CONFIG_SPL_RELOC_TEXT_BASE
		Address to relocate to.  If unspecified, this is equal to
		CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).

		CONFIG_SPL_BSS_START_ADDR
		Link address for the BSS within the SPL binary.

		CONFIG_SPL_BSS_MAX_SIZE
		Maximum size in memory allocated to the SPL BSS.
		When defined, the linker checks that the actual memory used
		by SPL from __bss_start to __bss_end does not exceed it.
		CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
		must not be both defined at the same time.

		CONFIG_SPL_STACK
		Adress of the start of the stack SPL will use

		CONFIG_SPL_RELOC_STACK
		Adress of the start of the stack SPL will use after
		relocation.  If unspecified, this is equal to
		CONFIG_SPL_STACK.

		CONFIG_SYS_SPL_MALLOC_START
		Starting address of the malloc pool used in SPL.

		CONFIG_SYS_SPL_MALLOC_SIZE
		The size of the malloc pool used in SPL.

		CONFIG_SPL_FRAMEWORK
		Enable the SPL framework under common/.  This framework
		supports MMC, NAND and YMODEM loading of U-Boot and NAND
		NAND loading of the Linux Kernel.

		CONFIG_SPL_OS_BOOT
		Enable booting directly to an OS from SPL.
		See also: doc/README.falcon

		CONFIG_SPL_DISPLAY_PRINT
		For ARM, enable an optional function to print more information
		about the running system.

		CONFIG_SPL_INIT_MINIMAL
		Arch init code should be built for a very small image

		CONFIG_SPL_LIBCOMMON_SUPPORT
		Support for common/libcommon.o in SPL binary

		CONFIG_SPL_LIBDISK_SUPPORT
		Support for disk/libdisk.o in SPL binary

		CONFIG_SPL_I2C_SUPPORT
		Support for drivers/i2c/libi2c.o in SPL binary

		CONFIG_SPL_GPIO_SUPPORT
		Support for drivers/gpio/libgpio.o in SPL binary

		CONFIG_SPL_MMC_SUPPORT
		Support for drivers/mmc/libmmc.o in SPL binary

		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
		CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
		CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
		Address, size and partition on the MMC to load U-Boot from
		when the MMC is being used in raw mode.

		CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
		Sector to load kernel uImage from when MMC is being
		used in raw mode (for Falcon mode)

		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
		CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
		Sector and number of sectors to load kernel argument
		parameters from when MMC is being used in raw mode
		(for falcon mode)

		CONFIG_SPL_FAT_SUPPORT
		Support for fs/fat/libfat.o in SPL binary

		CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
		Filename to read to load U-Boot when reading from FAT

		CONFIG_SPL_FAT_LOAD_KERNEL_NAME
		Filename to read to load kernel uImage when reading
		from FAT (for Falcon mode)

		CONFIG_SPL_FAT_LOAD_ARGS_NAME
		Filename to read to load kernel argument parameters
		when reading from FAT (for Falcon mode)

		CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
		Set this for NAND SPL on PPC mpc83xx targets, so that
		start.S waits for the rest of the SPL to load before
		continuing (the hardware starts execution after just
		loading the first page rather than the full 4K).

		CONFIG_SPL_SKIP_RELOCATE
		Avoid SPL relocation

		CONFIG_SPL_NAND_BASE
		Include nand_base.c in the SPL.  Requires
		CONFIG_SPL_NAND_DRIVERS.

		CONFIG_SPL_NAND_DRIVERS
		SPL uses normal NAND drivers, not minimal drivers.

		CONFIG_SPL_NAND_ECC
		Include standard software ECC in the SPL

		CONFIG_SPL_NAND_SIMPLE
		Support for NAND boot using simple NAND drivers that
		expose the cmd_ctrl() interface.

		CONFIG_SPL_MTD_SUPPORT
		Support for the MTD subsystem within SPL.  Useful for
		environment on NAND support within SPL.

		CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
		Set for the SPL on PPC mpc8xxx targets, support for
		drivers/ddr/fsl/libddr.o in SPL binary.

		CONFIG_SPL_COMMON_INIT_DDR
		Set for common ddr init with serial presence detect in
		SPL binary.

		CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
		CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
		CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
		CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
		CONFIG_SYS_NAND_ECCBYTES
		Defines the size and behavior of the NAND that SPL uses
		to read U-Boot

		CONFIG_SPL_NAND_BOOT
		Add support NAND boot

		CONFIG_SYS_NAND_U_BOOT_OFFS
		Location in NAND to read U-Boot from

		CONFIG_SYS_NAND_U_BOOT_DST
		Location in memory to load U-Boot to

		CONFIG_SYS_NAND_U_BOOT_SIZE
		Size of image to load

		CONFIG_SYS_NAND_U_BOOT_START
		Entry point in loaded image to jump to

		CONFIG_SYS_NAND_HW_ECC_OOBFIRST
		Define this if you need to first read the OOB and then the
		data. This is used for example on davinci plattforms.

		CONFIG_SPL_OMAP3_ID_NAND
		Support for an OMAP3-specific set of functions to return the
		ID and MFR of the first attached NAND chip, if present.

		CONFIG_SPL_SERIAL_SUPPORT
		Support for drivers/serial/libserial.o in SPL binary

		CONFIG_SPL_SPI_FLASH_SUPPORT
		Support for drivers/mtd/spi/libspi_flash.o in SPL binary

		CONFIG_SPL_SPI_SUPPORT
		Support for drivers/spi/libspi.o in SPL binary

		CONFIG_SPL_RAM_DEVICE
		Support for running image already present in ram, in SPL binary

		CONFIG_SPL_LIBGENERIC_SUPPORT
		Support for lib/libgeneric.o in SPL binary

		CONFIG_SPL_ENV_SUPPORT
		Support for the environment operating in SPL binary

		CONFIG_SPL_NET_SUPPORT
		Support for the net/libnet.o in SPL binary.
		It conflicts with SPL env from storage medium specified by
		CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE

		CONFIG_SPL_PAD_TO
		Image offset to which the SPL should be padded before appending
		the SPL payload. By default, this is defined as
		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.

		CONFIG_SPL_TARGET
		Final target image containing SPL and payload.  Some SPLs
		use an arch-specific makefile fragment instead, for
		example if more than one image needs to be produced.

		CONFIG_FIT_SPL_PRINT
		Printing information about a FIT image adds quite a bit of
		code to SPL. So this is normally disabled in SPL. Use this
		option to re-enable it. This will affect the output of the
		bootm command when booting a FIT image.

- TPL framework
		CONFIG_TPL
		Enable building of TPL globally.

		CONFIG_TPL_PAD_TO
		Image offset to which the TPL should be padded before appending
		the TPL payload. By default, this is defined as
		CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
		CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
		payload without any padding, or >= CONFIG_SPL_MAX_SIZE.

Modem Support:
--------------

[so far only for SMDK2400 boards]

- Modem support enable:
		CONFIG_MODEM_SUPPORT

- RTS/CTS Flow control enable:
		CONFIG_HWFLOW

- Modem debug support:
		CONFIG_MODEM_SUPPORT_DEBUG

		Enables debugging stuff (char screen[1024], dbg())
		for modem support. Useful only with BDI2000.

- Interrupt support (PPC):

		There are common interrupt_init() and timer_interrupt()
		for all PPC archs. interrupt_init() calls interrupt_init_cpu()
		for CPU specific initialization. interrupt_init_cpu()
		should set decrementer_count to appropriate value. If
		CPU resets decrementer automatically after interrupt
		(ppc4xx) it should set decrementer_count to zero.
		timer_interrupt() calls timer_interrupt_cpu() for CPU
		specific handling. If board has watchdog / status_led
		/ other_activity_monitor it works automatically from
		general timer_interrupt().

- General:

		In the target system modem support is enabled when a
		specific key (key combination) is pressed during
		power-on. Otherwise U-Boot will boot normally
		(autoboot). The key_pressed() function is called from
		board_init(). Currently key_pressed() is a dummy
		function, returning 1 and thus enabling modem
		initialization.

		If there are no modem init strings in the
		environment, U-Boot proceed to autoboot; the
		previous output (banner, info printfs) will be
		suppressed, though.

		See also: doc/README.Modem

Board initialization settings:
------------------------------

During Initialization u-boot calls a number of board specific functions
to allow the preparation of board specific prerequisites, e.g. pin setup
before drivers are initialized. To enable these callbacks the
following configuration macros have to be defined. Currently this is
architecture specific, so please check arch/your_architecture/lib/board.c
typically in board_init_f() and board_init_r().

- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
- CONFIG_BOARD_LATE_INIT: Call board_late_init()
- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()

Configuration Settings:
-----------------------

- CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
		Optionally it can be defined to support 64-bit memory commands.

- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
		undefine this when you're short of memory.

- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
		width of the commands listed in the 'help' command output.

- CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
		prompt for user input.

- CONFIG_SYS_CBSIZE:	Buffer size for input from the Console

- CONFIG_SYS_PBSIZE:	Buffer size for Console output

- CONFIG_SYS_MAXARGS:	max. Number of arguments accepted for monitor commands

- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
		the application (usually a Linux kernel) when it is
		booted

- CONFIG_SYS_BAUDRATE_TABLE:
		List of legal baudrate settings for this board.

- CONFIG_SYS_CONSOLE_INFO_QUIET
		Suppress display of console information at boot.

- CONFIG_SYS_CONSOLE_IS_IN_ENV
		If the board specific function
			extern int overwrite_console (void);
		returns 1, the stdin, stderr and stdout are switched to the
		serial port, else the settings in the environment are used.

- CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
		Enable the call to overwrite_console().

- CONFIG_SYS_CONSOLE_ENV_OVERWRITE
		Enable overwrite of previous console environment settings.

- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
		Begin and End addresses of the area used by the
		simple memory test.

- CONFIG_SYS_ALT_MEMTEST:
		Enable an alternate, more extensive memory test.

- CONFIG_SYS_MEMTEST_SCRATCH:
		Scratch address used by the alternate memory test
		You only need to set this if address zero isn't writeable

- CONFIG_SYS_MEM_TOP_HIDE (PPC only):
		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
		this specified memory area will get subtracted from the top
		(end) of RAM and won't get "touched" at all by U-Boot. By
		fixing up gd->ram_size the Linux kernel should gets passed
		the now "corrected" memory size and won't touch it either.
		This should work for arch/ppc and arch/powerpc. Only Linux
		board ports in arch/powerpc with bootwrapper support that
		recalculate the memory size from the SDRAM controller setup
		will have to get fixed in Linux additionally.

		This option can be used as a workaround for the 440EPx/GRx
		CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
		be touched.

		WARNING: Please make sure that this value is a multiple of
		the Linux page size (normally 4k). If this is not the case,
		then the end address of the Linux memory will be located at a
		non page size aligned address and this could cause major
		problems.

- CONFIG_SYS_LOADS_BAUD_CHANGE:
		Enable temporary baudrate change while serial download

- CONFIG_SYS_SDRAM_BASE:
		Physical start address of SDRAM. _Must_ be 0 here.

- CONFIG_SYS_MBIO_BASE:
		Physical start address of Motherboard I/O (if using a
		Cogent motherboard)

- CONFIG_SYS_FLASH_BASE:
		Physical start address of Flash memory.

- CONFIG_SYS_MONITOR_BASE:
		Physical start address of boot monitor code (set by
		make config files to be same as the text base address
		(CONFIG_SYS_TEXT_BASE) used when linking) - same as
		CONFIG_SYS_FLASH_BASE when booting from flash.

- CONFIG_SYS_MONITOR_LEN:
		Size of memory reserved for monitor code, used to
		determine _at_compile_time_ (!) if the environment is
		embedded within the U-Boot image, or in a separate
		flash sector.

- CONFIG_SYS_MALLOC_LEN:
		Size of DRAM reserved for malloc() use.

- CONFIG_SYS_MALLOC_F_LEN
		Size of the malloc() pool for use before relocation. If
		this is defined, then a very simple malloc() implementation
		will become available before relocation. The address is just
		below the global data, and the stack is moved down to make
		space.

		This feature allocates regions with increasing addresses
		within the region. calloc() is supported, but realloc()
		is not available. free() is supported but does nothing.
		The memory will be freed (or in fact just forgotton) when
		U-Boot relocates itself.

		Pre-relocation malloc() is only supported on sandbox
		at present but is fairly easy to enable for other archs.

		Pre-relocation malloc() is only supported on ARM at present
		but is fairly easy to enable for other archs.

- CONFIG_SYS_BOOTM_LEN:
		Normally compressed uImages are limited to an
		uncompressed size of 8 MBytes. If this is not enough,
		you can define CONFIG_SYS_BOOTM_LEN in your board config file
		to adjust this setting to your needs.

- CONFIG_SYS_BOOTMAPSZ:
		Maximum size of memory mapped by the startup code of
		the Linux kernel; all data that must be processed by
		the Linux kernel (bd_info, boot arguments, FDT blob if
		used) must be put below this limit, unless "bootm_low"
		environment variable is defined and non-zero. In such case
		all data for the Linux kernel must be between "bootm_low"
		and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.	 The environment
		variable "bootm_mapsize" will override the value of
		CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
		then the value in "bootm_size" will be used instead.

- CONFIG_SYS_BOOT_RAMDISK_HIGH:
		Enable initrd_high functionality.  If defined then the
		initrd_high feature is enabled and the bootm ramdisk subcommand
		is enabled.

- CONFIG_SYS_BOOT_GET_CMDLINE:
		Enables allocating and saving kernel cmdline in space between
		"bootm_low" and "bootm_low" + BOOTMAPSZ.

- CONFIG_SYS_BOOT_GET_KBD:
		Enables allocating and saving a kernel copy of the bd_info in
		space between "bootm_low" and "bootm_low" + BOOTMAPSZ.

- CONFIG_SYS_MAX_FLASH_BANKS:
		Max number of Flash memory banks

- CONFIG_SYS_MAX_FLASH_SECT:
		Max number of sectors on a Flash chip

- CONFIG_SYS_FLASH_ERASE_TOUT:
		Timeout for Flash erase operations (in ms)

- CONFIG_SYS_FLASH_WRITE_TOUT:
		Timeout for Flash write operations (in ms)

- CONFIG_SYS_FLASH_LOCK_TOUT
		Timeout for Flash set sector lock bit operation (in ms)

- CONFIG_SYS_FLASH_UNLOCK_TOUT
		Timeout for Flash clear lock bits operation (in ms)

- CONFIG_SYS_FLASH_PROTECTION
		If defined, hardware flash sectors protection is used
		instead of U-Boot software protection.

- CONFIG_SYS_DIRECT_FLASH_TFTP:

		Enable TFTP transfers directly to flash memory;
		without this option such a download has to be
		performed in two steps: (1) download to RAM, and (2)
		copy from RAM to flash.

		The two-step approach is usually more reliable, since
		you can check if the download worked before you erase
		the flash, but in some situations (when system RAM is
		too limited to allow for a temporary copy of the
		downloaded image) this option may be very useful.

- CONFIG_SYS_FLASH_CFI:
		Define if the flash driver uses extra elements in the
		common flash structure for storing flash geometry.

- CONFIG_FLASH_CFI_DRIVER
		This option also enables the building of the cfi_flash driver
		in the drivers directory

- CONFIG_FLASH_CFI_MTD
		This option enables the building of the cfi_mtd driver
		in the drivers directory. The driver exports CFI flash
		to the MTD layer.

- CONFIG_SYS_FLASH_USE_BUFFER_WRITE
		Use buffered writes to flash.

- CONFIG_FLASH_SPANSION_S29WS_N
		s29ws-n MirrorBit flash has non-standard addresses for buffered
		write commands.

- CONFIG_SYS_FLASH_QUIET_TEST
		If this option is defined, the common CFI flash doesn't
		print it's warning upon not recognized FLASH banks. This
		is useful, if some of the configured banks are only
		optionally available.

- CONFIG_FLASH_SHOW_PROGRESS
		If defined (must be an integer), print out countdown
		digits and dots.  Recommended value: 45 (9..1) for 80
		column displays, 15 (3..1) for 40 column displays.

- CONFIG_FLASH_VERIFY
		If defined, the content of the flash (destination) is compared
		against the source after the write operation. An error message
		will be printed when the contents are not identical.
		Please note that this option is useless in nearly all cases,
		since such flash programming errors usually are detected earlier
		while unprotecting/erasing/programming. Please only enable
		this option if you really know what you are doing.

- CONFIG_SYS_RX_ETH_BUFFER:
		Defines the number of Ethernet receive buffers. On some
		Ethernet controllers it is recommended to set this value
		to 8 or even higher (EEPRO100 or 405 EMAC), since all
		buffers can be full shortly after enabling the interface
		on high Ethernet traffic.
		Defaults to 4 if not defined.

- CONFIG_ENV_MAX_ENTRIES

	Maximum number of entries in the hash table that is used
	internally to store the environment settings. The default
	setting is supposed to be generous and should work in most
	cases. This setting can be used to tune behaviour; see
	lib/hashtable.c for details.

- CONFIG_ENV_FLAGS_LIST_DEFAULT
- CONFIG_ENV_FLAGS_LIST_STATIC
	Enable validation of the values given to environment variables when
	calling env set.  Variables can be restricted to only decimal,
	hexadecimal, or boolean.  If CONFIG_CMD_NET is also defined,
	the variables can also be restricted to IP address or MAC address.

	The format of the list is:
		type_attribute = [s|d|x|b|i|m]
		access_atribute = [a|r|o|c]
		attributes = type_attribute[access_atribute]
		entry = variable_name[:attributes]
		list = entry[,list]

	The type attributes are:
		s - String (default)
		d - Decimal
		x - Hexadecimal
		b - Boolean ([1yYtT|0nNfF])
		i - IP address
		m - MAC address

	The access attributes are:
		a - Any (default)
		r - Read-only
		o - Write-once
		c - Change-default

	- CONFIG_ENV_FLAGS_LIST_DEFAULT
		Define this to a list (string) to define the ".flags"
		envirnoment variable in the default or embedded environment.

	- CONFIG_ENV_FLAGS_LIST_STATIC
		Define this to a list (string) to define validation that
		should be done if an entry is not found in the ".flags"
		environment variable.  To override a setting in the static
		list, simply add an entry for the same variable name to the
		".flags" variable.

- CONFIG_ENV_ACCESS_IGNORE_FORCE
	If defined, don't allow the -f switch to env set override variable
	access flags.

- CONFIG_SYS_GENERIC_BOARD
	This selects the architecture-generic board system instead of the
	architecture-specific board files. It is intended to move boards
	to this new framework over time. Defining this will disable the
	arch/foo/lib/board.c file and use common/board_f.c and
	common/board_r.c instead. To use this option your architecture
	must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
	its config.mk file). If you find problems enabling this option on
	your board please report the problem and send patches!

- CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
	This is set by OMAP boards for the max time that reset should
	be asserted. See doc/README.omap-reset-time for details on how
	the value can be calulated on a given board.

The following definitions that deal with the placement and management
of environment data (variable area); in general, we support the
following configurations:

- CONFIG_BUILD_ENVCRC:

	Builds up envcrc with the target environment so that external utils
	may easily extract it and embed it in final U-Boot images.

- CONFIG_ENV_IS_IN_FLASH:

	Define this if the environment is in flash memory.

	a) The environment occupies one whole flash sector, which is
	   "embedded" in the text segment with the U-Boot code. This
	   happens usually with "bottom boot sector" or "top boot
	   sector" type flash chips, which have several smaller
	   sectors at the start or the end. For instance, such a
	   layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
	   such a case you would place the environment in one of the
	   4 kB sectors - with U-Boot code before and after it. With
	   "top boot sector" type flash chips, you would put the
	   environment in one of the last sectors, leaving a gap
	   between U-Boot and the environment.

	- CONFIG_ENV_OFFSET:

	   Offset of environment data (variable area) to the
	   beginning of flash memory; for instance, with bottom boot
	   type flash chips the second sector can be used: the offset
	   for this sector is given here.

	   CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.

	- CONFIG_ENV_ADDR:

	   This is just another way to specify the start address of
	   the flash sector containing the environment (instead of
	   CONFIG_ENV_OFFSET).

	- CONFIG_ENV_SECT_SIZE:

	   Size of the sector containing the environment.


	b) Sometimes flash chips have few, equal sized, BIG sectors.
	   In such a case you don't want to spend a whole sector for
	   the environment.

	- CONFIG_ENV_SIZE:

	   If you use this in combination with CONFIG_ENV_IS_IN_FLASH
	   and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
	   of this flash sector for the environment. This saves
	   memory for the RAM copy of the environment.

	   It may also save flash memory if you decide to use this
	   when your environment is "embedded" within U-Boot code,
	   since then the remainder of the flash sector could be used