README

		"pRAM-clean":

			IVMS8, IVML24, SPD8xx, TQM8xxL,
			HERMES, IP860, RPXlite, LWMON,
			FLAGADM, TQM8260

- Access to physical memory region (> 4GB)
		Some basic support is provided for operations on memory not
		normally accessible to U-Boot - e.g. some architectures
		support access to more than 4GB of memory on 32-bit
		machines using physical address extension or similar.
		Define CONFIG_PHYSMEM to access this basic support, which
		currently only supports clearing the memory.

- Error Recovery:
		CONFIG_PANIC_HANG

		Define this variable to stop the system in case of a
		fatal error, so that you have to reset it manually.
		This is probably NOT a good idea for an embedded
		system where you want the system to reboot
		automatically as fast as possible, but it may be
		useful during development since you can try to debug
		the conditions that lead to the situation.

		CONFIG_NET_RETRY_COUNT

		This variable defines the number of retries for
		network operations like ARP, RARP, TFTP, or BOOTP
		before giving up the operation. If not defined, a
		default value of 5 is used.

		CONFIG_ARP_TIMEOUT

		Timeout waiting for an ARP reply in milliseconds.

		CONFIG_NFS_TIMEOUT

		Timeout in milliseconds used in NFS protocol.
		If you encounter "ERROR: Cannot umount" in nfs command,
		try longer timeout such as
		#define CONFIG_NFS_TIMEOUT 10000UL

- Command Interpreter:
		CONFIG_AUTO_COMPLETE

		Enable auto completion of commands using TAB.

		CONFIG_SYS_PROMPT_HUSH_PS2

		This defines the secondary prompt string, which is
		printed when the command interpreter needs more input
		to complete a command. Usually "> ".

	Note:

		In the current implementation, the local variables
		space and global environment variables space are
		separated. Local variables are those you define by
		simply typing `name=value'. To access a local
		variable later on, you have write `$name' or
		`${name}'; to execute the contents of a variable
		directly type `$name' at the command prompt.

		Global environment variables are those you use
		setenv/printenv to work with. To run a command stored
		in such a variable, you need to use the run command,
		and you must not use the '$' sign to access them.

		To store commands and special characters in a
		variable, please use double quotation marks
		surrounding the whole text of the variable, instead
		of the backslashes before semicolons and special
		symbols.

- Command Line Editing and History:
		CONFIG_CMDLINE_EDITING

		Enable editing and History functions for interactive
		command line input operations

- Default Environment:
		CONFIG_EXTRA_ENV_SETTINGS

		Define this to contain any number of null terminated
		strings (variable = value pairs) that will be part of
		the default environment compiled into the boot image.

		For example, place something like this in your
		board's config file:

		#define CONFIG_EXTRA_ENV_SETTINGS \
			"myvar1=value1\0" \
			"myvar2=value2\0"

		Warning: This method is based on knowledge about the
		internal format how the environment is stored by the
		U-Boot code. This is NOT an official, exported
		interface! Although it is unlikely that this format
		will change soon, there is no guarantee either.
		You better know what you are doing here.

		Note: overly (ab)use of the default environment is
		discouraged. Make sure to check other ways to preset
		the environment like the "source" command or the
		boot command first.

		CONFIG_ENV_VARS_UBOOT_CONFIG

		Define this in order to add variables describing the
		U-Boot build configuration to the default environment.
		These will be named arch, cpu, board, vendor, and soc.

		Enabling this option will cause the following to be defined:

		- CONFIG_SYS_ARCH
		- CONFIG_SYS_CPU
		- CONFIG_SYS_BOARD
		- CONFIG_SYS_VENDOR
		- CONFIG_SYS_SOC

		CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG

		Define this in order to add variables describing certain
		run-time determined information about the hardware to the
		environment.  These will be named board_name, board_rev.

		CONFIG_DELAY_ENVIRONMENT

		Normally the environment is loaded when the board is
		initialised so that it is available to U-Boot. This inhibits
		that so that the environment is not available until
		explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
		this is instead controlled by the value of
		/config/load-environment.

- DataFlash Support:
		CONFIG_HAS_DATAFLASH

		Defining this option enables DataFlash features and
		allows to read/write in Dataflash via the standard
		commands cp, md...

- Serial Flash support
		CONFIG_CMD_SF

		Defining this option enables SPI flash commands
		'sf probe/read/write/erase/update'.

		Usage requires an initial 'probe' to define the serial
		flash parameters, followed by read/write/erase/update
		commands.

		The following defaults may be provided by the platform
		to handle the common case when only a single serial
		flash is present on the system.

		CONFIG_SF_DEFAULT_BUS		Bus identifier
		CONFIG_SF_DEFAULT_CS		Chip-select
		CONFIG_SF_DEFAULT_MODE 		(see include/spi.h)
		CONFIG_SF_DEFAULT_SPEED		in Hz

		CONFIG_CMD_SF_TEST

		Define this option to include a destructive SPI flash
		test ('sf test').

		CONFIG_SPI_FLASH_BAR		Ban/Extended Addr Reg

		Define this option to use the Bank addr/Extended addr
		support on SPI flashes which has size > 16Mbytes.

		CONFIG_SF_DUAL_FLASH		Dual flash memories

		Define this option to use dual flash support where two flash
		memories can be connected with a given cs line.
		Currently Xilinx Zynq qspi supports these type of connections.

		CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
		enable the W#/Vpp signal to disable writing to the status
		register on ST MICRON flashes like the N25Q128.
		The status register write enable/disable bit, combined with
		the W#/VPP signal provides hardware data protection for the
		device as follows: When the enable/disable bit is set to 1,
		and the W#/VPP signal is driven LOW, the status register
		nonvolatile bits become read-only and the WRITE STATUS REGISTER
		operation will not execute. The only way to exit this
		hardware-protected mode is to drive W#/VPP HIGH.

- SystemACE Support:
		CONFIG_SYSTEMACE

		Adding this option adds support for Xilinx SystemACE
		chips attached via some sort of local bus. The address
		of the chip must also be defined in the
		CONFIG_SYS_SYSTEMACE_BASE macro. For example:

		#define CONFIG_SYSTEMACE
		#define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000

		When SystemACE support is added, the "ace" device type
		becomes available to the fat commands, i.e. fatls.

- TFTP Fixed UDP Port:
		CONFIG_TFTP_PORT

		If this is defined, the environment variable tftpsrcp
		is used to supply the TFTP UDP source port value.
		If tftpsrcp isn't defined, the normal pseudo-random port
		number generator is used.

		Also, the environment variable tftpdstp is used to supply
		the TFTP UDP destination port value.  If tftpdstp isn't
		defined, the normal port 69 is used.

		The purpose for tftpsrcp is to allow a TFTP server to
		blindly start the TFTP transfer using the pre-configured
		target IP address and UDP port. This has the effect of
		"punching through" the (Windows XP) firewall, allowing
		the remainder of the TFTP transfer to proceed normally.
		A better solution is to properly configure the firewall,
		but sometimes that is not allowed.

- Hashing support:
		CONFIG_CMD_HASH

		This enables a generic 'hash' command which can produce
		hashes / digests from a few algorithms (e.g. SHA1, SHA256).

		CONFIG_HASH_VERIFY

		Enable the hash verify command (hash -v). This adds to code
		size a little.

		CONFIG_SHA1 - This option enables support of hashing using SHA1
		algorithm. The hash is calculated in software.
		CONFIG_SHA256 - This option enables support of hashing using
		SHA256 algorithm. The hash is calculated in software.
		CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
		for SHA1/SHA256 hashing.
		This affects the 'hash' command and also the
		hash_lookup_algo() function.
		CONFIG_SHA_PROG_HW_ACCEL - This option enables
		hardware-acceleration for SHA1/SHA256 progressive hashing.
		Data can be streamed in a block at a time and the hashing
		is performed in hardware.

		Note: There is also a sha1sum command, which should perhaps
		be deprecated in favour of 'hash sha1'.

- Freescale i.MX specific commands:
		CONFIG_CMD_HDMIDETECT
		This enables 'hdmidet' command which returns true if an
		HDMI monitor is detected.  This command is i.MX 6 specific.

		CONFIG_CMD_BMODE
		This enables the 'bmode' (bootmode) command for forcing
		a boot from specific media.

		This is useful for forcing the ROM's usb downloader to
		activate upon a watchdog reset which is nice when iterating
		on U-Boot.  Using the reset button or running bmode normal
		will set it back to normal.  This command currently
		supports i.MX53 and i.MX6.

- Signing support:
		CONFIG_RSA

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

		The Modular Exponentiation algorithm in RSA is implemented using
		driver model. So CONFIG_DM needs to be enabled by default for this
		library to function.

		The signing part is build into mkimage regardless of this
		option. The software based modular exponentiation is built into
		mkimage irrespective 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. If
		CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
		hashing is available using hardware, RSA library will use it.
		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.

		CONFIG_MTD_NAND_VERIFY_WRITE
		verify if the written data is correct reread.

- 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.


		CONFIG_MTD_UBI_WL_THRESHOLD
		This parameter defines the maximum difference between the highest
		erase counter value and the lowest erase counter value of eraseblocks
		of UBI devices. When this threshold is exceeded, UBI starts performing
		wear leveling by means of moving data from eraseblock with low erase
		counter to eraseblocks with high erase counter.

		The default value should be OK for SLC NAND flashes, NOR flashes and
		other flashes which have eraseblock life-cycle 100000 or more.
		However, in case of MLC NAND flashes which typically have eraseblock
		life-cycle less than 10000, the threshold should be lessened (e.g.,
		to 128 or 256, although it does not have to be power of 2).

		default: 4096

		CONFIG_MTD_UBI_BEB_LIMIT
		This option specifies the maximum bad physical eraseblocks UBI
		expects on the MTD device (per 1024 eraseblocks). If the
		underlying flash does not admit of bad eraseblocks (e.g. NOR
		flash), this value is ignored.

		NAND datasheets often specify the minimum and maximum NVM
		(Number of Valid Blocks) for the flashes' endurance lifetime.
		The maximum expected bad eraseblocks per 1024 eraseblocks
		then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
		which gives 20 for most NANDs (MaxNVB is basically the total
		count of eraseblocks on the chip).

		To put it differently, if this value is 20, UBI will try to
		reserve about 1.9% of physical eraseblocks for bad blocks
		handling. And that will be 1.9% of eraseblocks on the entire
		NAND chip, not just the MTD partition UBI attaches. This means
		that if you have, say, a NAND flash chip admits maximum 40 bad
		eraseblocks, and it is split on two MTD partitions of the same
		size, UBI will reserve 40 eraseblocks when attaching a
		partition.

		default: 20

		CONFIG_MTD_UBI_FASTMAP
		Fastmap is a mechanism which allows attaching an UBI device
		in nearly constant time. Instead of scanning the whole MTD device it
		only has to locate a checkpoint (called fastmap) on the device.
		The on-flash fastmap contains all information needed to attach
		the device. Using fastmap makes only sense on large devices where
		attaching by scanning takes long. UBI will not automatically install
		a fastmap on old images, but you can set the UBI parameter
		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
		that fastmap-enabled images are still usable with UBI implementations
		without	fastmap support. On typical flash devices the whole fastmap
		fits into one PEB. UBI will reserve PEBs to hold two fastmaps.

		CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
		Set this parameter to enable fastmap automatically on images
		without a fastmap.
		default: 0

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

		CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
		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_SYS_MMCSD_FS_BOOT_PARTITION
		Partition on the MMC to load U-Boot from when the MMC is being
		used in fs mode

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

		CONFIG_SPL_EXT_SUPPORT
		Support for EXT filesystem in SPL binary

		CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
		Filename to read to load U-Boot when reading from filesystem

		CONFIG_SPL_FS_LOAD_KERNEL_NAME
		Filename to read to load kernel uImage when reading
		from filesystem (for Falcon mode)

		CONFIG_SPL_FS_LOAD_ARGS_NAME
		Filename to read to load kernel argument parameters
		when reading from filesystem (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_NAND_RAW_ONLY
		Support to boot only raw u-boot.bin images. Use this only
		if you need to save space.

		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 platforms.

		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.