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#
# (C) Copyright 2000 - 2012
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#

Summary:
========

This directory contains the source code for U-Boot, a boot loader for
Embedded boards based on PowerPC, ARM, MIPS and several other
processors, which can be installed in a boot ROM and used to
initialize and test the hardware or to download and run application
code.

The development of U-Boot is closely related to Linux: some parts of
the source code originate in the Linux source tree, we have some
header files in common, and special provision has been made to
support booting of Linux images.

Some attention has been paid to make this software easily
configurable and extendable. For instance, all monitor commands are
implemented with the same call interface, so that it's very easy to
add new commands. Also, instead of permanently adding rarely used
code (for instance hardware test utilities) to the monitor, you can
load and run it dynamically.


Status:
=======

In general, all boards for which a configuration option exists in the
Makefile have been tested to some extent and can be considered
"working". In fact, many of them are used in production systems.

In case of problems see the CHANGELOG and CREDITS files to find out
who contributed the specific port. The MAINTAINERS file lists board
maintainers.

Note: There is no CHANGELOG file in the actual U-Boot source tree;
it can be created dynamically from the Git log using:

	make CHANGELOG


Where to get help:
==================

In case you have questions about, problems with or contributions for
U-Boot you should send a message to the U-Boot mailing list at
<u-boot@lists.denx.de>. There is also an archive of previous traffic
on the mailing list - please search the archive before asking FAQ's.
Please see http://lists.denx.de/pipermail/u-boot and
http://dir.gmane.org/gmane.comp.boot-loaders.u-boot


Where to get source code:
=========================

The U-Boot source code is maintained in the git repository at
git://www.denx.de/git/u-boot.git ; you can browse it online at
http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary

The "snapshot" links on this page allow you to download tarballs of
any version you might be interested in. Official releases are also
available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
directory.

Pre-built (and tested) images are available from
ftp://ftp.denx.de/pub/u-boot/images/


Where we come from:
===================

- start from 8xxrom sources
- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
- clean up code
- make it easier to add custom boards
- make it possible to add other [PowerPC] CPUs
- extend functions, especially:
  * Provide extended interface to Linux boot loader
  * S-Record download
  * network boot
  * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
- create ARMBoot project (http://sourceforge.net/projects/armboot)
- add other CPU families (starting with ARM)
- create U-Boot project (http://sourceforge.net/projects/u-boot)
- current project page: see http://www.denx.de/wiki/U-Boot


Names and Spelling:
===================

The "official" name of this project is "Das U-Boot". The spelling
"U-Boot" shall be used in all written text (documentation, comments
in source files etc.). Example:

	This is the README file for the U-Boot project.

File names etc. shall be based on the string "u-boot". Examples:

	include/asm-ppc/u-boot.h

	#include <asm/u-boot.h>

Variable names, preprocessor constants etc. shall be either based on
the string "u_boot" or on "U_BOOT". Example:

	U_BOOT_VERSION		u_boot_logo
	IH_OS_U_BOOT		u_boot_hush_start


Versioning:
===========

Starting with the release in October 2008, the names of the releases
were changed from numerical release numbers without deeper meaning
into a time stamp based numbering. Regular releases are identified by
names consisting of the calendar year and month of the release date.
Additional fields (if present) indicate release candidates or bug fix
releases in "stable" maintenance trees.

Examples:
	U-Boot v2009.11	    - Release November 2009
	U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
	U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release


Directory Hierarchy:
====================

/arch			Architecture specific files
  /arm			Files generic to ARM architecture
    /cpu		CPU specific files
      /arm720t		Files specific to ARM 720 CPUs
      /arm920t		Files specific to ARM 920 CPUs
	/at91		Files specific to Atmel AT91RM9200 CPU
	/imx		Files specific to Freescale MC9328 i.MX CPUs
	/s3c24x0	Files specific to Samsung S3C24X0 CPUs
      /arm925t		Files specific to ARM 925 CPUs
      /arm926ejs	Files specific to ARM 926 CPUs
      /arm1136		Files specific to ARM 1136 CPUs
      /ixp		Files specific to Intel XScale IXP CPUs
      /pxa		Files specific to Intel XScale PXA CPUs
      /s3c44b0		Files specific to Samsung S3C44B0 CPUs
      /sa1100		Files specific to Intel StrongARM SA1100 CPUs
    /lib		Architecture specific library files
  /avr32		Files generic to AVR32 architecture
    /cpu		CPU specific files
    /lib		Architecture specific library files
  /blackfin		Files generic to Analog Devices Blackfin architecture
    /cpu		CPU specific files
    /lib		Architecture specific library files
  /x86			Files generic to x86 architecture
    /cpu		CPU specific files
    /lib		Architecture specific library files
  /m68k			Files generic to m68k architecture
    /cpu		CPU specific files
      /mcf52x2		Files specific to Freescale ColdFire MCF52x2 CPUs
      /mcf5227x		Files specific to Freescale ColdFire MCF5227x CPUs
      /mcf532x		Files specific to Freescale ColdFire MCF5329 CPUs
      /mcf5445x		Files specific to Freescale ColdFire MCF5445x CPUs
      /mcf547x_8x	Files specific to Freescale ColdFire MCF547x_8x CPUs
    /lib		Architecture specific library files
  /microblaze		Files generic to microblaze architecture
    /cpu		CPU specific files
    /lib		Architecture specific library files
  /mips			Files generic to MIPS architecture
    /cpu		CPU specific files
      /mips32		Files specific to MIPS32 CPUs
      /xburst		Files specific to Ingenic XBurst CPUs
    /lib		Architecture specific library files
  /nds32		Files generic to NDS32 architecture
    /cpu		CPU specific files
      /n1213		Files specific to Andes Technology N1213 CPUs
    /lib		Architecture specific library files
  /nios2		Files generic to Altera NIOS2 architecture
    /cpu		CPU specific files
    /lib		Architecture specific library files
  /powerpc		Files generic to PowerPC architecture
    /cpu		CPU specific files
      /74xx_7xx		Files specific to Freescale MPC74xx and 7xx CPUs
      /mpc5xx		Files specific to Freescale MPC5xx CPUs
      /mpc5xxx		Files specific to Freescale MPC5xxx CPUs
      /mpc8xx		Files specific to Freescale MPC8xx CPUs
      /mpc8220		Files specific to Freescale MPC8220 CPUs
      /mpc824x		Files specific to Freescale MPC824x CPUs
      /mpc8260		Files specific to Freescale MPC8260 CPUs
      /mpc85xx		Files specific to Freescale MPC85xx CPUs
      /ppc4xx		Files specific to AMCC PowerPC 4xx CPUs
    /lib		Architecture specific library files
  /sh			Files generic to SH architecture
    /cpu		CPU specific files
      /sh2		Files specific to sh2 CPUs
      /sh3		Files specific to sh3 CPUs
      /sh4		Files specific to sh4 CPUs
    /lib		Architecture specific library files
  /sparc		Files generic to SPARC architecture
    /cpu		CPU specific files
      /leon2		Files specific to Gaisler LEON2 SPARC CPU
      /leon3		Files specific to Gaisler LEON3 SPARC CPU
    /lib		Architecture specific library files
/api			Machine/arch independent API for external apps
/board			Board dependent files
/common			Misc architecture independent functions
/disk			Code for disk drive partition handling
/doc			Documentation (don't expect too much)
/drivers		Commonly used device drivers
/examples		Example code for standalone applications, etc.
/fs			Filesystem code (cramfs, ext2, jffs2, etc.)
/include		Header Files
/lib			Files generic to all architectures
  /libfdt		Library files to support flattened device trees
  /lzma			Library files to support LZMA decompression
  /lzo			Library files to support LZO decompression
/net			Networking code
/post			Power On Self Test
/rtc			Real Time Clock drivers
/tools			Tools to build S-Record or U-Boot images, etc.

Software Configuration:
=======================

Configuration is usually done using C preprocessor defines; the
rationale behind that is to avoid dead code whenever possible.

There are two classes of configuration variables:

* Configuration _OPTIONS_:
  These are selectable by the user and have names beginning with
  "CONFIG_".

* Configuration _SETTINGS_:
  These depend on the hardware etc. and should not be meddled with if
  you don't know what you're doing; they have names beginning with
  "CONFIG_SYS_".

Later we will add a configuration tool - probably similar to or even
identical to what's used for the Linux kernel. Right now, we have to
do the configuration by hand, which means creating some symbolic
links and editing some configuration files. We use the TQM8xxL boards
as an example here.


Selection of Processor Architecture and Board Type:
---------------------------------------------------

For all supported boards there are ready-to-use default
configurations available; just type "make <board_name>_config".

Example: For a TQM823L module type:

	cd u-boot
	make TQM823L_config

For the Cogent platform, you need to specify the CPU type as well;
e.g. "make cogent_mpc8xx_config". And also configure the cogent
directory according to the instructions in cogent/README.


Configuration Options:
----------------------

Configuration depends on the combination of board and CPU type; all
such information is kept in a configuration file
"include/configs/<board_name>.h".

Example: For a TQM823L module, all configuration settings are in
"include/configs/TQM823L.h".


Many of the options are named exactly as the corresponding Linux
kernel configuration options. The intention is to make it easier to
build a config tool - later.


The following options need to be configured:

- CPU Type:	Define exactly one, e.g. CONFIG_MPC85XX.

- Board Type:	Define exactly one, e.g. CONFIG_MPC8540ADS.

- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
		Define exactly one, e.g. CONFIG_ATSTK1002

- CPU Module Type: (if CONFIG_COGENT is defined)
		Define exactly one of
		CONFIG_CMA286_60_OLD
--- FIXME --- not tested yet:
		CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
		CONFIG_CMA287_23, CONFIG_CMA287_50

- Motherboard Type: (if CONFIG_COGENT is defined)
		Define exactly one of
		CONFIG_CMA101, CONFIG_CMA102

- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
		Define one or more of
		CONFIG_CMA302

- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
		Define one or more of
		CONFIG_LCD_HEARTBEAT	- update a character position on
					  the LCD display every second with
					  a "rotator" |\-/|\-/

- Board flavour: (if CONFIG_MPC8260ADS is defined)
		CONFIG_ADSTYPE
		Possible values are:
			CONFIG_SYS_8260ADS	- original MPC8260ADS
			CONFIG_SYS_8266ADS	- MPC8266ADS
			CONFIG_SYS_PQ2FADS	- PQ2FADS-ZU or PQ2FADS-VR
			CONFIG_SYS_8272ADS	- MPC8272ADS

- Marvell Family Member
		CONFIG_SYS_MVFS		- define it if you want to enable
					  multiple fs option at one time
					  for marvell soc family

- MPC824X Family Member (if CONFIG_MPC824X is defined)
		Define exactly one of
		CONFIG_MPC8240, CONFIG_MPC8245

- 8xx CPU Options: (if using an MPC8xx CPU)
		CONFIG_8xx_GCLK_FREQ	- deprecated: CPU clock if
					  get_gclk_freq() cannot work
					  e.g. if there is no 32KHz
					  reference PIT/RTC clock
		CONFIG_8xx_OSCLK	- PLL input clock (either EXTCLK
					  or XTAL/EXTAL)

- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
		CONFIG_SYS_8xx_CPUCLK_MIN
		CONFIG_SYS_8xx_CPUCLK_MAX
		CONFIG_8xx_CPUCLK_DEFAULT
			See doc/README.MPC866

		CONFIG_SYS_MEASURE_CPUCLK

		Define this to measure the actual CPU clock instead
		of relying on the correctness of the configured
		values. Mostly useful for board bringup to make sure
		the PLL is locked at the intended frequency. Note
		that this requires a (stable) reference clock (32 kHz
		RTC clock or CONFIG_SYS_8XX_XIN)

		CONFIG_SYS_DELAYED_ICACHE

		Define this option if you want to enable the
		ICache only when Code runs from RAM.

- 85xx CPU Options:
		CONFIG_SYS_PPC64

		Specifies that the core is a 64-bit PowerPC implementation (implements
		the "64" category of the Power ISA). This is necessary for ePAPR
		compliance, among other possible reasons.

		CONFIG_SYS_FSL_TBCLK_DIV

		Defines the core time base clock divider ratio compared to the
		system clock.  On most PQ3 devices this is 8, on newer QorIQ
		devices it can be 16 or 32.  The ratio varies from SoC to Soc.

		CONFIG_SYS_FSL_PCIE_COMPAT

		Defines the string to utilize when trying to match PCIe device
		tree nodes for the given platform.

		CONFIG_SYS_PPC_E500_DEBUG_TLB

		Enables a temporary TLB entry to be used during boot to work
		around limitations in e500v1 and e500v2 external debugger
		support. This reduces the portions of the boot code where
		breakpoints and single stepping do not work.  The value of this
		symbol should be set to the TLB1 entry to be used for this
		purpose.

		CONFIG_SYS_FSL_ERRATUM_A004510

		Enables a workaround for erratum A004510.  If set,
		then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.

		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
		CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)

		Defines one or two SoC revisions (low 8 bits of SVR)
		for which the A004510 workaround should be applied.

		The rest of SVR is either not relevant to the decision
		of whether the erratum is present (e.g. p2040 versus
		p2041) or is implied by the build target, which controls
		whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.

		See Freescale App Note 4493 for more information about
		this erratum.

		CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY

		This is the value to write into CCSR offset 0x18600
		according to the A004510 workaround.

- Generic CPU options:
		CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN

		Defines the endianess of the CPU. Implementation of those
		values is arch specific.

- Intel Monahans options:
		CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO

		Defines the Monahans run mode to oscillator
		ratio. Valid values are 8, 16, 24, 31. The core
		frequency is this value multiplied by 13 MHz.

		CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO

		Defines the Monahans turbo mode to oscillator
		ratio. Valid values are 1 (default if undefined) and
		2. The core frequency as calculated above is multiplied
		by this value.

- MIPS CPU options:
		CONFIG_SYS_INIT_SP_OFFSET

		Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
		pointer. This is needed for the temporary stack before
		relocation.

		CONFIG_SYS_MIPS_CACHE_MODE

		Cache operation mode for the MIPS CPU.
		See also arch/mips/include/asm/mipsregs.h.
		Possible values are:
			CONF_CM_CACHABLE_NO_WA
			CONF_CM_CACHABLE_WA
			CONF_CM_UNCACHED
			CONF_CM_CACHABLE_NONCOHERENT
			CONF_CM_CACHABLE_CE
			CONF_CM_CACHABLE_COW
			CONF_CM_CACHABLE_CUW
			CONF_CM_CACHABLE_ACCELERATED

		CONFIG_SYS_XWAY_EBU_BOOTCFG

		Special option for Lantiq XWAY SoCs for booting from NOR flash.
		See also arch/mips/cpu/mips32/start.S.

		CONFIG_XWAY_SWAP_BYTES

		Enable compilation of tools/xway-swap-bytes needed for Lantiq
		XWAY SoCs for booting from NOR flash. The U-Boot image needs to
		be swapped if a flash programmer is used.

- ARM options:
		CONFIG_SYS_EXCEPTION_VECTORS_HIGH

		Select high exception vectors of the ARM core, e.g., do not
		clear the V bit of the c1 register of CP15.

		CONFIG_SYS_THUMB_BUILD

		Use this flag to build U-Boot using the Thumb instruction
		set for ARM architectures. Thumb instruction set provides
		better code density. For ARM architectures that support
		Thumb2 this flag will result in Thumb2 code generated by
		GCC.

		CONFIG_ARM_ERRATA_716044
		CONFIG_ARM_ERRATA_742230
		CONFIG_ARM_ERRATA_743622
		CONFIG_ARM_ERRATA_751472

		If set, the workarounds for these ARM errata are applied early
		during U-Boot startup. Note that these options force the
		workarounds to be applied; no CPU-type/version detection
		exists, unlike the similar options in the Linux kernel. Do not
		set these options unless they apply!

- CPU timer options:
		CONFIG_SYS_HZ

		The frequency of the timer returned by get_timer().
		get_timer() must operate in milliseconds and this CONFIG
		option must be set to 1000.

- Linux Kernel Interface:
		CONFIG_CLOCKS_IN_MHZ

		U-Boot stores all clock information in Hz
		internally. For binary compatibility with older Linux
		kernels (which expect the clocks passed in the
		bd_info data to be in MHz) the environment variable
		"clocks_in_mhz" can be defined so that U-Boot
		converts clock data to MHZ before passing it to the
		Linux kernel.
		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
		"clocks_in_mhz=1" is automatically included in the
		default environment.

		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]

		When transferring memsize parameter to linux, some versions
		expect it to be in bytes, others in MB.
		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.

		CONFIG_OF_LIBFDT

		New kernel versions are expecting firmware settings to be
		passed using flattened device trees (based on open firmware
		concepts).

		CONFIG_OF_LIBFDT
		 * New libfdt-based support
		 * Adds the "fdt" command
		 * The bootm command automatically updates the fdt

		OF_CPU - The proper name of the cpus node (only required for
			MPC512X and MPC5xxx based boards).
		OF_SOC - The proper name of the soc node (only required for
			MPC512X and MPC5xxx based boards).
		OF_TBCLK - The timebase frequency.
		OF_STDOUT_PATH - The path to the console device

		boards with QUICC Engines require OF_QE to set UCC MAC
		addresses

		CONFIG_OF_BOARD_SETUP

		Board code has addition modification that it wants to make
		to the flat device tree before handing it off to the kernel

		CONFIG_OF_BOOT_CPU

		This define fills in the correct boot CPU in the boot
		param header, the default value is zero if undefined.

		CONFIG_OF_IDE_FIXUP

		U-Boot can detect if an IDE device is present or not.
		If not, and this new config option is activated, U-Boot
		removes the ATA node from the DTS before booting Linux,
		so the Linux IDE driver does not probe the device and
		crash. This is needed for buggy hardware (uc101) where
		no pull down resistor is connected to the signal IDE5V_DD7.

		CONFIG_MACH_TYPE	[relevant for ARM only][mandatory]

		This setting is mandatory for all boards that have only one
		machine type and must be used to specify the machine type
		number as it appears in the ARM machine registry
		(see http://www.arm.linux.org.uk/developer/machines/).
		Only boards that have multiple machine types supported
		in a single configuration file and the machine type is
		runtime discoverable, do not have to use this setting.

- vxWorks boot parameters:

		bootvx constructs a valid bootline using the following
		environments variables: bootfile, ipaddr, serverip, hostname.
		It loads the vxWorks image pointed bootfile.

		CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
		CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
		CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
		CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters

		CONFIG_SYS_VXWORKS_ADD_PARAMS

		Add it at the end of the bootline. E.g "u=username pw=secret"

		Note: If a "bootargs" environment is defined, it will overwride
		the defaults discussed just above.

- Cache Configuration:
		CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
		CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
		CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot

- Cache Configuration for ARM:
		CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
				      controller
		CONFIG_SYS_PL310_BASE - Physical base address of PL310
					controller register space

- Serial Ports:
		CONFIG_PL010_SERIAL

		Define this if you want support for Amba PrimeCell PL010 UARTs.

		CONFIG_PL011_SERIAL

		Define this if you want support for Amba PrimeCell PL011 UARTs.

		CONFIG_PL011_CLOCK

		If you have Amba PrimeCell PL011 UARTs, set this variable to
		the clock speed of the UARTs.

		CONFIG_PL01x_PORTS

		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
		define this to a list of base addresses for each (supported)
		port. See e.g. include/configs/versatile.h

		CONFIG_PL011_SERIAL_RLCR

		Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
		have separate receive and transmit line control registers.  Set
		this variable to initialize the extra register.

		CONFIG_PL011_SERIAL_FLUSH_ON_INIT

		On some platforms (e.g. U8500) U-Boot is loaded by a second stage
		boot loader that has already initialized the UART.  Define this
		variable to flush the UART at init time.


- Console Interface:
		Depending on board, define exactly one serial port
		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
		console by defining CONFIG_8xx_CONS_NONE

		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
		port routines must be defined elsewhere
		(i.e. serial_init(), serial_getc(), ...)

		CONFIG_CFB_CONSOLE
		Enables console device for a color framebuffer. Needs following
		defines (cf. smiLynxEM, i8042)
			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
						(default big endian)
			VIDEO_HW_RECTFILL	graphic chip supports
						rectangle fill
						(cf. smiLynxEM)
			VIDEO_HW_BITBLT		graphic chip supports
						bit-blit (cf. smiLynxEM)
			VIDEO_VISIBLE_COLS	visible pixel columns
						(cols=pitch)
			VIDEO_VISIBLE_ROWS	visible pixel rows
			VIDEO_PIXEL_SIZE	bytes per pixel
			VIDEO_DATA_FORMAT	graphic data format
						(0-5, cf. cfb_console.c)
			VIDEO_FB_ADRS		framebuffer address
			VIDEO_KBD_INIT_FCT	keyboard int fct
						(i.e. i8042_kbd_init())
			VIDEO_TSTC_FCT		test char fct
						(i.e. i8042_tstc)
			VIDEO_GETC_FCT		get char fct
						(i.e. i8042_getc)
			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
						(requires blink timer
						cf. i8042.c)
			CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
			CONFIG_CONSOLE_TIME	display time/date info in
						upper right corner
						(requires CONFIG_CMD_DATE)
			CONFIG_VIDEO_LOGO	display Linux logo in
						upper left corner
			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
						linux_logo.h for logo.
						Requires CONFIG_VIDEO_LOGO
			CONFIG_CONSOLE_EXTRA_INFO
						additional board info beside
						the logo

		When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
		a limited number of ANSI escape sequences (cursor control,
		erase functions and limited graphics rendition control).

		When CONFIG_CFB_CONSOLE is defined, video console is
		default i/o. Serial console can be forced with
		environment 'console=serial'.

		When CONFIG_SILENT_CONSOLE is defined, all console
		messages (by U-Boot and Linux!) can be silenced with
		the "silent" environment variable. See
		doc/README.silent for more information.

- Console Baudrate:
		CONFIG_BAUDRATE - in bps
		Select one of the baudrates listed in
		CONFIG_SYS_BAUDRATE_TABLE, see below.
		CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale

- Console Rx buffer length
		With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
		the maximum receive buffer length for the SMC.
		This option is actual only for 82xx and 8xx possible.
		If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
		must be defined, to setup the maximum idle timeout for
		the SMC.

- Pre-Console Buffer:
		Prior to the console being initialised (i.e. serial UART
		initialised etc) all console output is silently discarded.
		Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
		buffer any console messages prior to the console being
		initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
		bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
		a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
		bytes are output before the console is initialised, the
		earlier bytes are discarded.

		'Sane' compilers will generate smaller code if
		CONFIG_PRE_CON_BUF_SZ is a power of 2

- Safe printf() functions
		Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
		the printf() functions. These are defined in
		include/vsprintf.h and include snprintf(), vsnprintf() and
		so on. Code size increase is approximately 300-500 bytes.
		If this option is not given then these functions will
		silently discard their buffer size argument - this means
		you are not getting any overflow checking in this case.

- Boot Delay:	CONFIG_BOOTDELAY - in seconds
		Delay before automatically booting the default image;
		set to -1 to disable autoboot.
		set to -2 to autoboot with no delay and not check for abort
		(even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).

		See doc/README.autoboot for these options that
		work with CONFIG_BOOTDELAY. None are required.
		CONFIG_BOOT_RETRY_TIME
		CONFIG_BOOT_RETRY_MIN
		CONFIG_AUTOBOOT_KEYED
		CONFIG_AUTOBOOT_PROMPT
		CONFIG_AUTOBOOT_DELAY_STR
		CONFIG_AUTOBOOT_STOP_STR
		CONFIG_AUTOBOOT_DELAY_STR2
		CONFIG_AUTOBOOT_STOP_STR2
		CONFIG_ZERO_BOOTDELAY_CHECK
		CONFIG_RESET_TO_RETRY

- Autoboot Command:
		CONFIG_BOOTCOMMAND
		Only needed when CONFIG_BOOTDELAY is enabled;
		define a command string that is automatically executed
		when no character is read on the console interface
		within "Boot Delay" after reset.

		CONFIG_BOOTARGS
		This can be used to pass arguments to the bootm
		command. The value of CONFIG_BOOTARGS goes into the
		environment value "bootargs".

		CONFIG_RAMBOOT and CONFIG_NFSBOOT
		The value of these goes into the environment as
		"ramboot" and "nfsboot" respectively, and can be used
		as a convenience, when switching between booting from
		RAM and NFS.

- Pre-Boot Commands:
		CONFIG_PREBOOT

		When this option is #defined, the existence of the
		environment variable "preboot" will be checked
		immediately before starting the CONFIG_BOOTDELAY
		countdown and/or running the auto-boot command resp.
		entering interactive mode.

		This feature is especially useful when "preboot" is
		automatically generated or modified. For an example
		see the LWMON board specific code: here "preboot" is
		modified when the user holds down a certain
		combination of keys on the (special) keyboard when
		booting the systems

- Serial Download Echo Mode:
		CONFIG_LOADS_ECHO
		If defined to 1, all characters received during a
		serial download (using the "loads" command) are
		echoed back. This might be needed by some terminal
		emulations (like "cu"), but may as well just take
		time on others. This setting #define's the initial
		value of the "loads_echo" environment variable.

- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
		CONFIG_KGDB_BAUDRATE
		Select one of the baudrates listed in
		CONFIG_SYS_BAUDRATE_TABLE, see below.

- Monitor Functions:
		Monitor commands can be included or excluded
		from the build by using the #include files
		<config_cmd_all.h> and #undef'ing unwanted
		commands, or using <config_cmd_default.h>
		and augmenting with additional #define's
		for wanted commands.

		The default command configuration includes all commands
		except those marked below with a "*".

		CONFIG_CMD_ASKENV	* ask for env variable
		CONFIG_CMD_BDI		  bdinfo
		CONFIG_CMD_BEDBUG	* Include BedBug Debugger
		CONFIG_CMD_BMP		* BMP support
		CONFIG_CMD_BSP		* Board specific commands
		CONFIG_CMD_BOOTD	  bootd
		CONFIG_CMD_CACHE	* icache, dcache
		CONFIG_CMD_CONSOLE	  coninfo
		CONFIG_CMD_CRC32	* crc32
		CONFIG_CMD_DATE		* support for RTC, date/time...
		CONFIG_CMD_DHCP		* DHCP support
		CONFIG_CMD_DIAG		* Diagnostics
		CONFIG_CMD_DS4510	* ds4510 I2C gpio commands
		CONFIG_CMD_DS4510_INFO	* ds4510 I2C info command
		CONFIG_CMD_DS4510_MEM	* ds4510 I2C eeprom/sram commansd
		CONFIG_CMD_DS4510_RST	* ds4510 I2C rst command
		CONFIG_CMD_DTT		* Digital Therm and Thermostat
		CONFIG_CMD_ECHO		  echo arguments
		CONFIG_CMD_EDITENV	  edit env variable
		CONFIG_CMD_EEPROM	* EEPROM read/write support
		CONFIG_CMD_ELF		* bootelf, bootvx
		CONFIG_CMD_ENV_CALLBACK	* display details about env callbacks
		CONFIG_CMD_ENV_FLAGS	* display details about env flags
		CONFIG_CMD_EXPORTENV	* export the environment
		CONFIG_CMD_EXT2		* ext2 command support
		CONFIG_CMD_EXT4		* ext4 command support
		CONFIG_CMD_SAVEENV	  saveenv
		CONFIG_CMD_FDC		* Floppy Disk Support
		CONFIG_CMD_FAT		* FAT command support
		CONFIG_CMD_FDOS		* Dos diskette Support
		CONFIG_CMD_FLASH	  flinfo, erase, protect
		CONFIG_CMD_FPGA		  FPGA device initialization support
		CONFIG_CMD_GETTIME	* Get time since boot
		CONFIG_CMD_GO		* the 'go' command (exec code)
		CONFIG_CMD_GREPENV	* search environment
		CONFIG_CMD_HASH		* calculate hash / digest
		CONFIG_CMD_HWFLOW	* RTS/CTS hw flow control
		CONFIG_CMD_I2C		* I2C serial bus support
		CONFIG_CMD_IDE		* IDE harddisk support
		CONFIG_CMD_IMI		  iminfo
		CONFIG_CMD_IMLS		  List all images found in NOR flash
		CONFIG_CMD_IMLS_NAND	  List all images found in NAND flash
		CONFIG_CMD_IMMAP	* IMMR dump support
		CONFIG_CMD_IMPORTENV	* import an environment
		CONFIG_CMD_INI		* import data from an ini file into the env
		CONFIG_CMD_IRQ		* irqinfo
		CONFIG_CMD_ITEST	  Integer/string test of 2 values
		CONFIG_CMD_JFFS2	* JFFS2 Support
		CONFIG_CMD_KGDB		* kgdb
		CONFIG_CMD_LDRINFO	  ldrinfo (display Blackfin loader)
		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
					  (169.254.*.*)
		CONFIG_CMD_LOADB	  loadb
		CONFIG_CMD_LOADS	  loads
		CONFIG_CMD_MD5SUM	  print md5 message digest
					  (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
		CONFIG_CMD_MEMINFO	* Display detailed memory information
		CONFIG_CMD_MEMORY	  md, mm, nm, mw, cp, cmp, crc, base,
					  loop, loopw
		CONFIG_CMD_MEMTEST	  mtest
		CONFIG_CMD_MISC		  Misc functions like sleep etc
		CONFIG_CMD_MMC		* MMC memory mapped support
		CONFIG_CMD_MII		* MII utility commands
		CONFIG_CMD_MTDPARTS	* MTD partition support
		CONFIG_CMD_NAND		* NAND support
		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
		CONFIG_CMD_PCA953X	* PCA953x I2C gpio commands
		CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
		CONFIG_CMD_PCI		* pciinfo
		CONFIG_CMD_PCMCIA		* PCMCIA support
		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
					  host
		CONFIG_CMD_PORTIO	* Port I/O
		CONFIG_CMD_READ		* Read raw data from partition
		CONFIG_CMD_REGINFO	* Register dump
		CONFIG_CMD_RUN		  run command in env variable
		CONFIG_CMD_SANDBOX	* sb command to access sandbox features
		CONFIG_CMD_SAVES	* save S record dump
		CONFIG_CMD_SCSI		* SCSI Support
		CONFIG_CMD_SDRAM	* print SDRAM configuration information
					  (requires CONFIG_CMD_I2C)
		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
					  (4xx only)
		CONFIG_CMD_SF		* Read/write/erase SPI NOR flash
		CONFIG_CMD_SHA1SUM	  print sha1 memory digest
					  (requires CONFIG_CMD_MEMORY)
		CONFIG_CMD_SOURCE	  "source" command Support
		CONFIG_CMD_SPI		* SPI serial bus support
		CONFIG_CMD_TFTPSRV	* TFTP transfer in server mode
		CONFIG_CMD_TFTPPUT	* TFTP put command (upload)
		CONFIG_CMD_TIME		* run command and report execution time (ARM specific)
		CONFIG_CMD_TIMER	* access to the system tick timer
		CONFIG_CMD_USB		* USB support
		CONFIG_CMD_CDP		* Cisco Discover Protocol support
		CONFIG_CMD_MFSL		* Microblaze FSL support


		EXAMPLE: If you want all functions except of network
		support you can write:

		#include "config_cmd_all.h"
		#undef CONFIG_CMD_NET

	Other Commands:
		fdt (flattened device tree) command: CONFIG_OF_LIBFDT

	Note:	Don't enable the "icache" and "dcache" commands
		(configuration option CONFIG_CMD_CACHE) unless you know
		what you (and your U-Boot users) are doing. Data
		cache cannot be enabled on systems like the 8xx or
		8260 (where accesses to the IMMR region must be
		uncached), and it cannot be disabled on all other
		systems where we (mis-) use the data cache to hold an
		initial stack and some data.


		XXX - this list needs to get updated!

- Device tree:
		CONFIG_OF_CONTROL
		If this variable is defined, U-Boot will use a device tree
		to configure its devices, instead of relying on statically
		compiled #defines in the board file. This option is
		experimental and only available on a few boards. The device
		tree is available in the global data as gd->fdt_blob.

		U-Boot needs to get its device tree from somewhere. This can
		be done using one of the two options below:

		CONFIG_OF_EMBED
		If this variable is defined, U-Boot will embed a device tree
		binary in its image. This device tree file should be in the
		board directory and called <soc>-<board>.dts. The binary file
		is then picked up in board_init_f() and made available through
		the global data structure as gd->blob.

		CONFIG_OF_SEPARATE
		If this variable is defined, U-Boot will build a device tree
		binary. It will be called u-boot.dtb. Architecture-specific
		code will locate it at run-time. Generally this works by:

			cat u-boot.bin u-boot.dtb >image.bin

		and in fact, U-Boot does this for you, creating a file called
		u-boot-dtb.bin which is useful in the common case. You can
		still use the individual files if you need something more
		exotic.

- Watchdog:
		CONFIG_WATCHDOG
		If this variable is defined, it enables watchdog
		support for the SoC. There must be support in the SoC
		specific code for a watchdog. For the 8xx and 8260
		CPUs, the SIU Watchdog feature is enabled in the SYPCR
		register.  When supported for a specific SoC is
		available, then no further board specific code should
		be needed to use it.

		CONFIG_HW_WATCHDOG
		When using a watchdog circuitry external to the used
		SoC, then define this variable and provide board
		specific code for the "hw_watchdog_reset" function.

- U-Boot Version:
		CONFIG_VERSION_VARIABLE
		If this variable is defined, an environment variable
		named "ver" is created by U-Boot showing the U-Boot
		version as printed by the "version" command.
		Any change to this variable will be reverted at the
		next reset.

- Real-Time Clock:

		When CONFIG_CMD_DATE is selected, the type of the RTC
		has to be selected, too. Define exactly one of the
		following options:

		CONFIG_RTC_MPC8xx	- use internal RTC of MPC8xx
		CONFIG_RTC_PCF8563	- use Philips PCF8563 RTC
		CONFIG_RTC_MC13XXX	- use MC13783 or MC13892 RTC
		CONFIG_RTC_MC146818	- use MC146818 RTC
		CONFIG_RTC_DS1307	- use Maxim, Inc. DS1307 RTC
		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
		CONFIG_SYS_RTC_DS1337_NOOSC	- Turn off the OSC output for DS1337
		CONFIG_SYS_RV3029_TCR	- enable trickle charger on
					  RV3029 RTC.

		Note that if the RTC uses I2C, then the I2C interface
		must also be configured. See I2C Support, below.

- GPIO Support:
		CONFIG_PCA953X		- use NXP's PCA953X series I2C GPIO
		CONFIG_PCA953X_INFO	- enable pca953x info command

		The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
		chip-ngpio pairs that tell the PCA953X driver the number of
		pins supported by a particular chip.

		Note that if the GPIO device uses I2C, then the I2C interface
		must also be configured. See I2C Support, below.

- Timestamp Support:

		When CONFIG_TIMESTAMP is selected, the timestamp
		(date and time) of an image is printed by image
		commands like bootm or iminfo. This option is
		automatically enabled when you select CONFIG_CMD_DATE .

- Partition Labels (disklabels) Supported:
		Zero or more of the following:
		CONFIG_MAC_PARTITION   Apple's MacOS partition table.
		CONFIG_DOS_PARTITION   MS Dos partition table, traditional on the
				       Intel architecture, USB sticks, etc.
		CONFIG_ISO_PARTITION   ISO partition table, used on CDROM etc.
		CONFIG_EFI_PARTITION   GPT partition table, common when EFI is the
				       bootloader.  Note 2TB partition limit; see
				       disk/part_efi.c
		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.

		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
		CONFIG_CMD_SCSI) you must configure support for at
		least one non-MTD partition type as well.

- IDE Reset method:
		CONFIG_IDE_RESET_ROUTINE - this is defined in several
		board configurations files but used nowhere!

		CONFIG_IDE_RESET - is this is defined, IDE Reset will
		be performed by calling the function
			ide_set_reset(int reset)
		which has to be defined in a board specific file

- ATAPI Support:
		CONFIG_ATAPI

		Set this to enable ATAPI support.

- LBA48 Support
		CONFIG_LBA48

		Set this to enable support for disks larger than 137GB
		Also look at CONFIG_SYS_64BIT_LBA.
		Whithout these , LBA48 support uses 32bit variables and will 'only'
		support disks up to 2.1TB.

		CONFIG_SYS_64BIT_LBA:
			When enabled, makes the IDE subsystem use 64bit sector addresses.
			Default is 32bit.

- SCSI Support:
		At the moment only there is only support for the
		SYM53C8XX SCSI controller; define
		CONFIG_SCSI_SYM53C8XX to enable it.

		CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
		CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
		CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
		maximum numbers of LUNs, SCSI ID's and target
		devices.
		CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)

                The environment variable 'scsidevs' is set to the number of
                SCSI devices found during the last scan.

- NETWORK Support (PCI):
		CONFIG_E1000
		Support for Intel 8254x/8257x gigabit chips.

		CONFIG_E1000_SPI
		Utility code for direct access to the SPI bus on Intel 8257x.
		This does not do anything useful unless you set at least one
		of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.

		CONFIG_E1000_SPI_GENERIC
		Allow generic access to the SPI bus on the Intel 8257x, for
		example with the "sspi" command.

		CONFIG_CMD_E1000
		Management command for E1000 devices.  When used on devices
		with SPI support you can reprogram the EEPROM from U-Boot.

		CONFIG_E1000_FALLBACK_MAC
		default MAC for empty EEPROM after production.

		CONFIG_EEPRO100
		Support for Intel 82557/82559/82559ER chips.
		Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
		write routine for first time initialisation.

		CONFIG_TULIP
		Support for Digital 2114x chips.
		Optional CONFIG_TULIP_SELECT_MEDIA for board specific
		modem chip initialisation (KS8761/QS6611).

		CONFIG_NATSEMI
		Support for National dp83815 chips.

		CONFIG_NS8382X
		Support for National dp8382[01] gigabit chips.

- NETWORK Support (other):

		CONFIG_DRIVER_AT91EMAC
		Support for AT91RM9200 EMAC.

			CONFIG_RMII
			Define this to use reduced MII inteface

			CONFIG_DRIVER_AT91EMAC_QUIET
			If this defined, the driver is quiet.
			The driver doen't show link status messages.

		CONFIG_CALXEDA_XGMAC
		Support for the Calxeda XGMAC device

		CONFIG_LAN91C96
		Support for SMSC's LAN91C96 chips.

			CONFIG_LAN91C96_BASE
			Define this to hold the physical address
			of the LAN91C96's I/O space

			CONFIG_LAN91C96_USE_32_BIT
			Define this to enable 32 bit addressing

		CONFIG_SMC91111
		Support for SMSC's LAN91C111 chip

			CONFIG_SMC91111_BASE
			Define this to hold the physical address
			of the device (I/O space)

			CONFIG_SMC_USE_32_BIT
			Define this if data bus is 32 bits

			CONFIG_SMC_USE_IOFUNCS
			Define this to use i/o functions instead of macros
			(some hardware wont work with macros)

		CONFIG_DRIVER_TI_EMAC
		Support for davinci emac

			CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
			Define this if you have more then 3 PHYs.

		CONFIG_FTGMAC100
		Support for Faraday's FTGMAC100 Gigabit SoC Ethernet

			CONFIG_FTGMAC100_EGIGA
			Define this to use GE link update with gigabit PHY.
			Define this if FTGMAC100 is connected to gigabit PHY.
			If your system has 10/100 PHY only, it might not occur
			wrong behavior. Because PHY usually return timeout or
			useless data when polling gigabit status and gigabit
			control registers. This behavior won't affect the
			correctnessof 10/100 link speed update.

		CONFIG_SMC911X
		Support for SMSC's LAN911x and LAN921x chips

			CONFIG_SMC911X_BASE
			Define this to hold the physical address
			of the device (I/O space)

			CONFIG_SMC911X_32_BIT
			Define this if data bus is 32 bits

			CONFIG_SMC911X_16_BIT
			Define this if data bus is 16 bits. If your processor
			automatically converts one 32 bit word to two 16 bit
			words you may also try CONFIG_SMC911X_32_BIT.

		CONFIG_SH_ETHER
		Support for Renesas on-chip Ethernet controller

			CONFIG_SH_ETHER_USE_PORT
			Define the number of ports to be used

			CONFIG_SH_ETHER_PHY_ADDR
			Define the ETH PHY's address

			CONFIG_SH_ETHER_CACHE_WRITEBACK
			If this option is set, the driver enables cache flush.

- TPM Support:
		CONFIG_GENERIC_LPC_TPM
		Support for generic parallel port TPM devices. Only one device
		per system is supported at this time.

			CONFIG_TPM_TIS_BASE_ADDRESS
			Base address where the generic TPM device is mapped
			to. Contemporary x86 systems usually map it at
			0xfed40000.

- USB Support:
		At the moment only the UHCI host controller is
		supported (PIP405, MIP405, MPC5200); define
		CONFIG_USB_UHCI to enable it.
		define CONFIG_USB_KEYBOARD to enable the USB Keyboard
		and define CONFIG_USB_STORAGE to enable the USB
		storage devices.
		Note:
		Supported are USB Keyboards and USB Floppy drives
		(TEAC FD-05PUB).
		MPC5200 USB requires additional defines:
			CONFIG_USB_CLOCK
				for 528 MHz Clock: 0x0001bbbb
			CONFIG_PSC3_USB
				for USB on PSC3
			CONFIG_USB_CONFIG
				for differential drivers: 0x00001000
				for single ended drivers: 0x00005000
				for differential drivers on PSC3: 0x00000100
				for single ended drivers on PSC3: 0x00004100
			CONFIG_SYS_USB_EVENT_POLL
				May be defined to allow interrupt polling
				instead of using asynchronous interrupts

		CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
		txfilltuning field in the EHCI controller on reset.

- USB Device:
		Define the below if you wish to use the USB console.
		Once firmware is rebuilt from a serial console issue the
		command "setenv stdin usbtty; setenv stdout usbtty" and
		attach your USB cable. The Unix command "dmesg" should print
		it has found a new device. The environment variable usbtty
		can be set to gserial or cdc_acm to enable your device to
		appear to a USB host as a Linux gserial device or a
		Common Device Class Abstract Control Model serial device.
		If you select usbtty = gserial you should be able to enumerate
		a Linux host by
		# modprobe usbserial vendor=0xVendorID product=0xProductID
		else if using cdc_acm, simply setting the environment
		variable usbtty to be cdc_acm should suffice. The following
		might be defined in YourBoardName.h

			CONFIG_USB_DEVICE
			Define this to build a UDC device

			CONFIG_USB_TTY
			Define this to have a tty type of device available to
			talk to the UDC device

			CONFIG_USBD_HS
			Define this to enable the high speed support for usb
			device and usbtty. If this feature is enabled, a routine
			int is_usbd_high_speed(void)
			also needs to be defined by the driver to dynamically poll
			whether the enumeration has succeded at high speed or full
			speed.

			CONFIG_SYS_CONSOLE_IS_IN_ENV
			Define this if you want stdin, stdout &/or stderr to
			be set to usbtty.

			mpc8xx:
				CONFIG_SYS_USB_EXTC_CLK 0xBLAH
				Derive USB clock from external clock "blah"
				- CONFIG_SYS_USB_EXTC_CLK 0x02

				CONFIG_SYS_USB_BRG_CLK 0xBLAH
				Derive USB clock from brgclk
				- CONFIG_SYS_USB_BRG_CLK 0x04

		If you have a USB-IF assigned VendorID then you may wish to
		define your own vendor specific values either in BoardName.h
		or directly in usbd_vendor_info.h. If you don't define
		CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
		CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
		should pretend to be a Linux device to it's target host.

			CONFIG_USBD_MANUFACTURER
			Define this string as the name of your company for
			- CONFIG_USBD_MANUFACTURER "my company"

			CONFIG_USBD_PRODUCT_NAME
			Define this string as the name of your product
			- CONFIG_USBD_PRODUCT_NAME "acme usb device"

			CONFIG_USBD_VENDORID
			Define this as your assigned Vendor ID from the USB
			Implementors Forum. This *must* be a genuine Vendor ID
			to avoid polluting the USB namespace.
			- CONFIG_USBD_VENDORID 0xFFFF

			CONFIG_USBD_PRODUCTID
			Define this as the unique Product ID
			for your device
			- CONFIG_USBD_PRODUCTID 0xFFFF

- ULPI Layer Support:
		The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
		the generic ULPI layer. The generic layer accesses the ULPI PHY
		via the platform viewport, so you need both the genric layer and
		the viewport enabled. Currently only Chipidea/ARC based
		viewport is supported.
		To enable the ULPI layer support, define CONFIG_USB_ULPI and
		CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
		If your ULPI phy needs a different reference clock than the
		standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
		the appropriate value in Hz.

- MMC Support:
		The MMC controller on the Intel PXA is supported. To
		enable this define CONFIG_MMC. The MMC can be
		accessed from the boot prompt by mapping the device
		to physical memory similar to flash. Command line is
		enabled with CONFIG_CMD_MMC. The MMC driver also works with
		the FAT fs. This is enabled with CONFIG_CMD_FAT.

		CONFIG_SH_MMCIF
		Support for Renesas on-chip MMCIF controller

			CONFIG_SH_MMCIF_ADDR
			Define the base address of MMCIF registers

			CONFIG_SH_MMCIF_CLK
			Define the clock frequency for MMCIF

- USB Device Firmware Update (DFU) class support:
		CONFIG_DFU_FUNCTION
		This enables the USB portion of the DFU USB class

		CONFIG_CMD_DFU
		This enables the command "dfu" which is used to have
		U-Boot create a DFU class device via USB.  This command
		requires that the "dfu_alt_info" environment variable be
		set and define the alt settings to expose to the host.

		CONFIG_DFU_MMC
		This enables support for exposing (e)MMC devices via DFU.

		CONFIG_DFU_NAND
		This enables support for exposing NAND devices via DFU.

		CONFIG_SYS_DFU_MAX_FILE_SIZE
		When updating files rather than the raw storage device,
		we use a static buffer to copy the file into and then write
		the buffer once we've been given the whole file.  Define
		this to the maximum filesize (in bytes) for the buffer.
		Default is 4 MiB if undefined.

- Journaling Flash filesystem support:
		CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
		CONFIG_JFFS2_NAND_DEV
		Define these for a default partition on a NAND device

		CONFIG_SYS_JFFS2_FIRST_SECTOR,
		CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
		Define these for a default partition on a NOR device

		CONFIG_SYS_JFFS_CUSTOM_PART
		Define this to create an own partition. You have to provide a
		function struct part_info* jffs2_part_info(int part_num)

		If you define only one JFFS2 partition you may also want to
		#define CONFIG_SYS_JFFS_SINGLE_PART	1
		to disable the command chpart. This is the default when you
		have not defined a custom partition

- FAT(File Allocation Table) filesystem write function support:
		CONFIG_FAT_WRITE

		Define this to enable support for saving memory data as a
		file in FAT formatted partition.

		This will also enable the command "fatwrite" enabling the
		user to write files to FAT.

CBFS (Coreboot Filesystem) support
		CONFIG_CMD_CBFS

		Define this to enable support for reading from a Coreboot
		filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
		and cbfsload.

- Keyboard Support:
		CONFIG_ISA_KEYBOARD

		Define this to enable standard (PC-Style) keyboard
		support

		CONFIG_I8042_KBD
		Standard PC keyboard driver with US (is default) and
		GERMAN key layout (switch via environment 'keymap=de') support.
		Export function i8042_kbd_init, i8042_tstc and i8042_getc
		for cfb_console. Supports cursor blinking.

- Video support:
		CONFIG_VIDEO

		Define this to enable video support (for output to
		video).

		CONFIG_VIDEO_CT69000

		Enable Chips & Technologies 69000 Video chip

		CONFIG_VIDEO_SMI_LYNXEM
		Enable Silicon Motion SMI 712/710/810 Video chip. The
		video output is selected via environment 'videoout'
		(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
		assumed.

		For the CT69000 and SMI_LYNXEM drivers, videomode is
		selected via environment 'videomode'. Two different ways
		are possible:
		- "videomode=num"   'num' is a standard LiLo mode numbers.
		Following standard modes are supported	(* is default):

		      Colors	640x480 800x600 1024x768 1152x864 1280x1024
		-------------+---------------------------------------------
		      8 bits |	0x301*	0x303	 0x305	  0x161	    0x307
		     15 bits |	0x310	0x313	 0x316	  0x162	    0x319
		     16 bits |	0x311	0x314	 0x317	  0x163	    0x31A
		     24 bits |	0x312	0x315	 0x318	    ?	    0x31B
		-------------+---------------------------------------------
		(i.e. setenv videomode 317; saveenv; reset;)

		- "videomode=bootargs" all the video parameters are parsed
		from the bootargs. (See drivers/video/videomodes.c)


		CONFIG_VIDEO_SED13806
		Enable Epson SED13806 driver. This driver supports 8bpp
		and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
		or CONFIG_VIDEO_SED13806_16BPP

		CONFIG_FSL_DIU_FB
		Enable the Freescale DIU video driver.	Reference boards for
		SOCs that have a DIU should define this macro to enable DIU
		support, and should also define these other macros:

			CONFIG_SYS_DIU_ADDR
			CONFIG_VIDEO
			CONFIG_CMD_BMP
			CONFIG_CFB_CONSOLE
			CONFIG_VIDEO_SW_CURSOR
			CONFIG_VGA_AS_SINGLE_DEVICE
			CONFIG_VIDEO_LOGO
			CONFIG_VIDEO_BMP_LOGO

		The DIU driver will look for the 'video-mode' environment
		variable, and if defined, enable the DIU as a console during
		boot.  See the documentation file README.video for a
		description of this variable.

		CONFIG_VIDEO_VGA

		Enable the VGA video / BIOS for x86. The alternative if you
		are using coreboot is to use the coreboot frame buffer
		driver.


- Keyboard Support:
		CONFIG_KEYBOARD

		Define this to enable a custom keyboard support.
		This simply calls drv_keyboard_init() which must be
		defined in your board-specific files.
		The only board using this so far is RBC823.

- LCD Support:	CONFIG_LCD

		Define this to enable LCD support (for output to LCD
		display); also select one of the supported displays
		by defining one of these:

		CONFIG_ATMEL_LCD:

			HITACHI TX09D70VM1CCA, 3.5", 240x320.

		CONFIG_NEC_NL6448AC33:

			NEC NL6448AC33-18. Active, color, single scan.

		CONFIG_NEC_NL6448BC20

			NEC NL6448BC20-08. 6.5", 640x480.
			Active, color, single scan.

		CONFIG_NEC_NL6448BC33_54

			NEC NL6448BC33-54. 10.4", 640x480.
			Active, color, single scan.

		CONFIG_SHARP_16x9

			Sharp 320x240. Active, color, single scan.
			It isn't 16x9, and I am not sure what it is.

		CONFIG_SHARP_LQ64D341

			Sharp LQ64D341 display, 640x480.
			Active, color, single scan.

		CONFIG_HLD1045

			HLD1045 display, 640x480.
			Active, color, single scan.

		CONFIG_OPTREX_BW

			Optrex	 CBL50840-2 NF-FW 99 22 M5
			or
			Hitachi	 LMG6912RPFC-00T
			or
			Hitachi	 SP14Q002

			320x240. Black & white.

		Normally display is black on white background; define
		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.

		CONFIG_LCD_ALIGNMENT

		Normally the LCD is page-aligned (tyically 4KB). If this is
		defined then the LCD will be aligned to this value instead.
		For ARM it is sometimes useful to use MMU_SECTION_SIZE
		here, since it is cheaper to change data cache settings on
		a per-section basis.

		CONFIG_CONSOLE_SCROLL_LINES

		When the console need to be scrolled, this is the number of
		lines to scroll by. It defaults to 1. Increasing this makes
		the console jump but can help speed up operation when scrolling
		is slow.

		CONFIG_LCD_BMP_RLE8

		Support drawing of RLE8-compressed bitmaps on the LCD.

		CONFIG_I2C_EDID

		Enables an 'i2c edid' command which can read EDID
		information over I2C from an attached LCD display.

- Splash Screen Support: CONFIG_SPLASH_SCREEN

		If this option is set, the environment is checked for
		a variable "splashimage". If found, the usual display
		of logo, copyright and system information on the LCD
		is suppressed and the BMP image at the address
		specified in "splashimage" is loaded instead. The
		console is redirected to the "nulldev", too. This
		allows for a "silent" boot where a splash screen is
		loaded very quickly after power-on.

		CONFIG_SPLASHIMAGE_GUARD

		If this option is set, then U-Boot will prevent the environment
		variable "splashimage" from being set to a problematic address
		(see README.displaying-bmps and README.arm-unaligned-accesses).
		This option is useful for targets where, due to alignment
		restrictions, an improperly aligned BMP image will cause a data
		abort. If you think you will not have problems with unaligned
		accesses (for example because your toolchain prevents them)
		there is no need to set this option.

		CONFIG_SPLASH_SCREEN_ALIGN

		If this option is set the splash image can be freely positioned
		on the screen. Environment variable "splashpos" specifies the
		position as "x,y". If a positive number is given it is used as
		number of pixel from left/top. If a negative number is given it
		is used as number of pixel from right/bottom. You can also
		specify 'm' for centering the image.

		Example:
		setenv splashpos m,m
			=> image at center of screen

		setenv splashpos 30,20
			=> image at x = 30 and y = 20

		setenv splashpos -10,m
			=> vertically centered image
			   at x = dspWidth - bmpWidth - 9

		CONFIG_SPLASH_SCREEN_PREPARE

		If this option is set then the board_splash_screen_prepare()
		function, which must be defined in your code, is called as part
		of the splash screen display sequence. It gives the board an
		opportunity to prepare the splash image data before it is
		processed and sent to the frame buffer by U-Boot.

- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP

		If this option is set, additionally to standard BMP
		images, gzipped BMP images can be displayed via the
		splashscreen support or the bmp command.

- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8

		If this option is set, 8-bit RLE compressed BMP images
		can be displayed via the splashscreen support or the
		bmp command.

- Do compresssing for memory range:
		CONFIG_CMD_ZIP

		If this option is set, it would use zlib deflate method
		to compress the specified memory at its best effort.

- Compression support:
		CONFIG_BZIP2

		If this option is set, support for bzip2 compressed
		images is included. If not, only uncompressed and gzip
		compressed images are supported.

		NOTE: the bzip2 algorithm requires a lot of RAM, so
		the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
		be at least 4MB.

		CONFIG_LZMA

		If this option is set, support for lzma compressed
		images is included.

		Note: The LZMA algorithm adds between 2 and 4KB of code and it
		requires an amount of dynamic memory that is given by the
		formula:

			(1846 + 768 << (lc + lp)) * sizeof(uint16)

		Where lc and lp stand for, respectively, Literal context bits
		and Literal pos bits.

		This value is upper-bounded by 14MB in the worst case. Anyway,
		for a ~4MB large kernel image, we have lc=3 and lp=0 for a
		total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
		a very small buffer.

		Use the lzmainfo tool to determinate the lc and lp values and
		then calculate the amount of needed dynamic memory (ensuring
		the appropriate CONFIG_SYS_MALLOC_LEN value).

- MII/PHY support:
		CONFIG_PHY_ADDR

		The address of PHY on MII bus.

		CONFIG_PHY_CLOCK_FREQ (ppc4xx)

		The clock frequency of the MII bus

		CONFIG_PHY_GIGE

		If this option is set, support for speed/duplex
		detection of gigabit PHY is included.

		CONFIG_PHY_RESET_DELAY

		Some PHY like Intel LXT971A need extra delay after
		reset before any MII register access is possible.
		For such PHY, set this option to the usec delay
		required. (minimum 300usec for LXT971A)

		CONFIG_PHY_CMD_DELAY (ppc4xx)

		Some PHY like Intel LXT971A need extra delay after
		command issued before MII status register can be read

- Ethernet address:
		CONFIG_ETHADDR
		CONFIG_ETH1ADDR
		CONFIG_ETH2ADDR
		CONFIG_ETH3ADDR
		CONFIG_ETH4ADDR
		CONFIG_ETH5ADDR

		Define a default value for Ethernet address to use
		for the respective Ethernet interface, in case this
		is not determined automatically.

- IP address:
		CONFIG_IPADDR

		Define a default value for the IP address to use for
		the default Ethernet interface, in case this is not
		determined through e.g. bootp.
		(Environment variable "ipaddr")

- Server IP address:
		CONFIG_SERVERIP

		Defines a default value for the IP address of a TFTP
		server to contact when using the "tftboot" command.
		(Environment variable "serverip")

		CONFIG_KEEP_SERVERADDR

		Keeps the server's MAC address, in the env 'serveraddr'
		for passing to bootargs (like Linux's netconsole option)

- Gateway IP address:
		CONFIG_GATEWAYIP

		Defines a default value for the IP address of the
		default router where packets to other networks are
		sent to.
		(Environment variable "gatewayip")

- Subnet mask:
		CONFIG_NETMASK

		Defines a default value for the subnet mask (or
		routing prefix) which is used to determine if an IP
		address belongs to the local subnet or needs to be
		forwarded through a router.
		(Environment variable "netmask")

- Multicast TFTP Mode:
		CONFIG_MCAST_TFTP

		Defines whether you want to support multicast TFTP as per
		rfc-2090; for example to work with atftp.  Lets lots of targets
		tftp down the same boot image concurrently.  Note: the Ethernet
		driver in use must provide a function: mcast() to join/leave a
		multicast group.

- BOOTP Recovery Mode:
		CONFIG_BOOTP_RANDOM_DELAY

		If you have many targets in a network that try to
		boot using BOOTP, you may want to avoid that all
		systems send out BOOTP requests at precisely the same
		moment (which would happen for instance at recovery
		from a power failure, when all systems will try to
		boot, thus flooding the BOOTP server. Defining
		CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
		inserted before sending out BOOTP requests. The
		following delays are inserted then:

		1st BOOTP request:	delay 0 ... 1 sec
		2nd BOOTP request:	delay 0 ... 2 sec
		3rd BOOTP request:	delay 0 ... 4 sec
		4th and following
		BOOTP requests:		delay 0 ... 8 sec

- DHCP Advanced Options:
		You can fine tune the DHCP functionality by defining
		CONFIG_BOOTP_* symbols:

		CONFIG_BOOTP_SUBNETMASK
		CONFIG_BOOTP_GATEWAY
		CONFIG_BOOTP_HOSTNAME
		CONFIG_BOOTP_NISDOMAIN
		CONFIG_BOOTP_BOOTPATH
		CONFIG_BOOTP_BOOTFILESIZE
		CONFIG_BOOTP_DNS
		CONFIG_BOOTP_DNS2
		CONFIG_BOOTP_SEND_HOSTNAME
		CONFIG_BOOTP_NTPSERVER
		CONFIG_BOOTP_TIMEOFFSET
		CONFIG_BOOTP_VENDOREX
		CONFIG_BOOTP_MAY_FAIL

		CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
		environment variable, not the BOOTP server.

		CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
		after the configured retry count, the call will fail
		instead of starting over.  This can be used to fail over
		to Link-local IP address configuration if the DHCP server
		is not available.

		CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
		serverip from a DHCP server, it is possible that more
		than one DNS serverip is offered to the client.
		If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
		serverip will be stored in the additional environment
		variable "dnsip2". The first DNS serverip is always
		stored in the variable "dnsip", when CONFIG_BOOTP_DNS
		is defined.

		CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
		to do a dynamic update of a DNS server. To do this, they
		need the hostname of the DHCP requester.
		If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
		of the "hostname" environment variable is passed as
		option 12 to the DHCP server.

		CONFIG_BOOTP_DHCP_REQUEST_DELAY

		A 32bit value in microseconds for a delay between
		receiving a "DHCP Offer" and sending the "DHCP Request".
		This fixes a problem with certain DHCP servers that don't
		respond 100% of the time to a "DHCP request". E.g. On an
		AT91RM9200 processor running at 180MHz, this delay needed
		to be *at least* 15,000 usec before a Windows Server 2003
		DHCP server would reply 100% of the time. I recommend at
		least 50,000 usec to be safe. The alternative is to hope
		that one of the retries will be successful but note that
		the DHCP timeout and retry process takes a longer than
		this delay.

 - Link-local IP address negotiation:
		Negotiate with other link-local clients on the local network
		for an address that doesn't require explicit configuration.
		This is especially useful if a DHCP server cannot be guaranteed
		to exist in all environments that the device must operate.

		See doc/README.link-local for more information.

 - CDP Options:
		CONFIG_CDP_DEVICE_ID

		The device id used in CDP trigger frames.

		CONFIG_CDP_DEVICE_ID_PREFIX

		A two character string which is prefixed to the MAC address
		of the device.

		CONFIG_CDP_PORT_ID

		A printf format string which contains the ascii name of
		the port. Normally is set to "eth%d" which sets
		eth0 for the first Ethernet, eth1 for the second etc.

		CONFIG_CDP_CAPABILITIES

		A 32bit integer which indicates the device capabilities;
		0x00000010 for a normal host which does not forwards.

		CONFIG_CDP_VERSION

		An ascii string containing the version of the software.

		CONFIG_CDP_PLATFORM

		An ascii string containing the name of the platform.

		CONFIG_CDP_TRIGGER

		A 32bit integer sent on the trigger.

		CONFIG_CDP_POWER_CONSUMPTION

		A 16bit integer containing the power consumption of the
		device in .1 of milliwatts.

		CONFIG_CDP_APPLIANCE_VLAN_TYPE

		A byte containing the id of the VLAN.

- Status LED:	CONFIG_STATUS_LED

		Several configurations allow to display the current
		status using a LED. For instance, the LED will blink
		fast while running U-Boot code, stop blinking as
		soon as a reply to a BOOTP request was received, and
		start blinking slow once the Linux kernel is running
		(supported by a status LED driver in the Linux
		kernel). Defining CONFIG_STATUS_LED enables this
		feature in U-Boot.

- CAN Support:	CONFIG_CAN_DRIVER

		Defining CONFIG_CAN_DRIVER enables CAN driver support
		on those systems that support this (optional)
		feature, like the TQM8xxL modules.

- I2C Support:	CONFIG_HARD_I2C | CONFIG_SOFT_I2C

		These enable I2C serial bus commands. Defining either of
		(but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
		include the appropriate I2C driver for the selected CPU.

		This will allow you to use i2c commands at the u-boot
		command line (as long as you set CONFIG_CMD_I2C in
		CONFIG_COMMANDS) and communicate with i2c based realtime
		clock chips. See common/cmd_i2c.c for a description of the
		command line interface.

		CONFIG_HARD_I2C selects a hardware I2C controller.

		CONFIG_SOFT_I2C configures u-boot to use a software (aka
		bit-banging) driver instead of CPM or similar hardware
		support for I2C.

		There are several other quantities that must also be
		defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.

		In both cases you will need to define CONFIG_SYS_I2C_SPEED
		to be the frequency (in Hz) at which you wish your i2c bus
		to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
		the CPU's i2c node address).

		Now, the u-boot i2c code for the mpc8xx
		(arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
		and so its address should therefore be cleared to 0 (See,
		eg, MPC823e User's Manual p.16-473). So, set
		CONFIG_SYS_I2C_SLAVE to 0.

		CONFIG_SYS_I2C_INIT_MPC5XXX

		When a board is reset during an i2c bus transfer
		chips might think that the current transfer is still
		in progress.  Reset the slave devices by sending start
		commands until the slave device responds.

		That's all that's required for CONFIG_HARD_I2C.

		If you use the software i2c interface (CONFIG_SOFT_I2C)
		then the following macros need to be defined (examples are
		from include/configs/lwmon.h):

		I2C_INIT

		(Optional). Any commands necessary to enable the I2C
		controller or configure ports.

		eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=	PB_SCL)

		I2C_PORT

		(Only for MPC8260 CPU). The I/O port to use (the code
		assumes both bits are on the same port). Valid values
		are 0..3 for ports A..D.

		I2C_ACTIVE

		The code necessary to make the I2C data line active
		(driven).  If the data line is open collector, this
		define can be null.

		eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=  PB_SDA)

		I2C_TRISTATE

		The code necessary to make the I2C data line tri-stated
		(inactive).  If the data line is open collector, this
		define can be null.

		eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)

		I2C_READ

		Code that returns true if the I2C data line is high,
		false if it is low.

		eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)

		I2C_SDA(bit)

		If <bit> is true, sets the I2C data line high. If it
		is false, it clears it (low).

		eg: #define I2C_SDA(bit) \
			if(bit) immr->im_cpm.cp_pbdat |=  PB_SDA; \
			else	immr->im_cpm.cp_pbdat &= ~PB_SDA

		I2C_SCL(bit)

		If <bit> is true, sets the I2C clock line high. If it
		is false, it clears it (low).

		eg: #define I2C_SCL(bit) \
			if(bit) immr->im_cpm.cp_pbdat |=  PB_SCL; \
			else	immr->im_cpm.cp_pbdat &= ~PB_SCL

		I2C_DELAY

		This delay is invoked four times per clock cycle so this
		controls the rate of data transfer.  The data rate thus
		is 1 / (I2C_DELAY * 4). Often defined to be something
		like:

		#define I2C_DELAY  udelay(2)

		CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA

		If your arch supports the generic GPIO framework (asm/gpio.h),
		then you may alternatively define the two GPIOs that are to be
		used as SCL / SDA.  Any of the previous I2C_xxx macros will
		have GPIO-based defaults assigned to them as appropriate.

		You should define these to the GPIO value as given directly to
		the generic GPIO functions.

		CONFIG_SYS_I2C_INIT_BOARD

		When a board is reset during an i2c bus transfer
		chips might think that the current transfer is still
		in progress. On some boards it is possible to access
		the i2c SCLK line directly, either by using the
		processor pin as a GPIO or by having a second pin
		connected to the bus. If this option is defined a
		custom i2c_init_board() routine in boards/xxx/board.c
		is run early in the boot sequence.

		CONFIG_SYS_I2C_BOARD_LATE_INIT

		An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
		defined a custom i2c_board_late_init() routine in
		boards/xxx/board.c is run AFTER the operations in i2c_init()
		is completed. This callpoint can be used to unreset i2c bus
		using CPU i2c controller register accesses for CPUs whose i2c
		controller provide such a method. It is called at the end of
		i2c_init() to allow i2c_init operations to setup the i2c bus
		controller on the CPU (e.g. setting bus speed & slave address).

		CONFIG_I2CFAST (PPC405GP|PPC405EP only)

		This option enables configuration of bi_iic_fast[] flags
		in u-boot bd_info structure based on u-boot environment
		variable "i2cfast". (see also i2cfast)

		CONFIG_I2C_MULTI_BUS

		This option allows the use of multiple I2C buses, each of which
		must have a controller.	 At any point in time, only one bus is
		active.	 To switch to a different bus, use the 'i2c dev' command.
		Note that bus numbering is zero-based.

		CONFIG_SYS_I2C_NOPROBES

		This option specifies a list of I2C devices that will be skipped
		when the 'i2c probe' command is issued.	 If CONFIG_I2C_MULTI_BUS
		is set, specify a list of bus-device pairs.  Otherwise, specify
		a 1D array of device addresses

		e.g.
			#undef	CONFIG_I2C_MULTI_BUS
			#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}

		will skip addresses 0x50 and 0x68 on a board with one I2C bus

			#define CONFIG_I2C_MULTI_BUS
			#define CONFIG_SYS_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}

		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1

		CONFIG_SYS_SPD_BUS_NUM

		If defined, then this indicates the I2C bus number for DDR SPD.
		If not defined, then U-Boot assumes that SPD is on I2C bus 0.

		CONFIG_SYS_RTC_BUS_NUM

		If defined, then this indicates the I2C bus number for the RTC.
		If not defined, then U-Boot assumes that RTC is on I2C bus 0.

		CONFIG_SYS_DTT_BUS_NUM

		If defined, then this indicates the I2C bus number for the DTT.
		If not defined, then U-Boot assumes that DTT is on I2C bus 0.

		CONFIG_SYS_I2C_DTT_ADDR:

		If defined, specifies the I2C address of the DTT device.
		If not defined, then U-Boot uses predefined value for
		specified DTT device.

		CONFIG_FSL_I2C

		Define this option if you want to use Freescale's I2C driver in
		drivers/i2c/fsl_i2c.c.

		CONFIG_I2C_MUX

		Define this option if you have I2C devices reached over 1 .. n
		I2C Muxes like the pca9544a. This option addes a new I2C
		Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
		new I2C Bus to the existing I2C Busses. If you select the
		new Bus with "i2c dev", u-bbot sends first the commandos for
		the muxes to activate this new "bus".

		CONFIG_I2C_MULTI_BUS must be also defined, to use this
		feature!

		Example:
		Adding a new I2C Bus reached over 2 pca9544a muxes
			The First mux with address 70 and channel 6
			The Second mux with address 71 and channel 4

		=> i2c bus pca9544a:70:6:pca9544a:71:4

		Use the "i2c bus" command without parameter, to get a list
		of I2C Busses with muxes:

		=> i2c bus
		Busses reached over muxes:
		Bus ID: 2
		  reached over Mux(es):
		    pca9544a@70 ch: 4
		Bus ID: 3
		  reached over Mux(es):
		    pca9544a@70 ch: 6
		    pca9544a@71 ch: 4
		=>

		If you now switch to the new I2C Bus 3 with "i2c dev 3"
		u-boot first sends the command to the mux@70 to enable
		channel 6, and then the command to the mux@71 to enable
		the channel 4.

		After that, you can use the "normal" i2c commands as
		usual to communicate with your I2C devices behind
		the 2 muxes.

		This option is actually implemented for the bitbanging
		algorithm in common/soft_i2c.c and for the Hardware I2C
		Bus on the MPC8260. But it should be not so difficult
		to add this option to other architectures.

		CONFIG_SOFT_I2C_READ_REPEATED_START

		defining this will force the i2c_read() function in
		the soft_i2c driver to perform an I2C repeated start
		between writing the address pointer and reading the
		data.  If this define is omitted the default behaviour
		of doing a stop-start sequence will be used.  Most I2C
		devices can use either method, but some require one or
		the other.

- SPI Support:	CONFIG_SPI

		Enables SPI driver (so far only tested with
		SPI EEPROM, also an instance works with Crystal A/D and
		D/As on the SACSng board)

		CONFIG_SH_SPI

		Enables the driver for SPI controller on SuperH. Currently
		only SH7757 is supported.

		CONFIG_SPI_X

		Enables extended (16-bit) SPI EEPROM addressing.
		(symmetrical to CONFIG_I2C_X)

		CONFIG_SOFT_SPI

		Enables a software (bit-bang) SPI driver rather than
		using hardware support. This is a general purpose
		driver that only requires three general I/O port pins
		(two outputs, one input) to function. If this is
		defined, the board configuration must define several
		SPI configuration items (port pins to use, etc). For
		an example, see include/configs/sacsng.h.

		CONFIG_HARD_SPI

		Enables a hardware SPI driver for general-purpose reads
		and writes.  As with CONFIG_SOFT_SPI, the board configuration
		must define a list of chip-select function pointers.
		Currently supported on some MPC8xxx processors.	 For an
		example, see include/configs/mpc8349emds.h.

		CONFIG_MXC_SPI

		Enables the driver for the SPI controllers on i.MX and MXC
		SoCs. Currently i.MX31/35/51 are supported.

- FPGA Support: CONFIG_FPGA

		Enables FPGA subsystem.

		CONFIG_FPGA_<vendor>

		Enables support for specific chip vendors.
		(ALTERA, XILINX)

		CONFIG_FPGA_<family>

		Enables support for FPGA family.
		(SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)

		CONFIG_FPGA_COUNT

		Specify the number of FPGA devices to support.

		CONFIG_SYS_FPGA_PROG_FEEDBACK

		Enable printing of hash marks during FPGA configuration.

		CONFIG_SYS_FPGA_CHECK_BUSY

		Enable checks on FPGA configuration interface busy
		status by the configuration function. This option
		will require a board or device specific function to
		be written.

		CONFIG_FPGA_DELAY

		If defined, a function that provides delays in the FPGA
		configuration driver.

		CONFIG_SYS_FPGA_CHECK_CTRLC
		Allow Control-C to interrupt FPGA configuration

		CONFIG_SYS_FPGA_CHECK_ERROR

		Check for configuration errors during FPGA bitfile
		loading. For example, abort during Virtex II
		configuration if the INIT_B line goes low (which
		indicated a CRC error).

		CONFIG_SYS_FPGA_WAIT_INIT

		Maximum time to wait for the INIT_B line to deassert
		after PROB_B has been deasserted during a Virtex II
		FPGA configuration sequence. The default time is 500
		ms.

		CONFIG_SYS_FPGA_WAIT_BUSY

		Maximum time to wait for BUSY to deassert during
		Virtex II FPGA configuration. The default is 5 ms.

		CONFIG_SYS_FPGA_WAIT_CONFIG

		Time to wait after FPGA configuration. The default is
		200 ms.

- Configuration Management:
		CONFIG_IDENT_STRING

		If defined, this string will be added to the U-Boot
		version information (U_BOOT_VERSION)

- Vendor Parameter Protection:

		U-Boot considers the values of the environment
		variables "serial#" (Board Serial Number) and
		"ethaddr" (Ethernet Address) to be parameters that
		are set once by the board vendor / manufacturer, and
		protects these variables from casual modification by
		the user. Once set, these variables are read-only,
		and write or delete attempts are rejected. You can
		change this behaviour:

		If CONFIG_ENV_OVERWRITE is #defined in your config
		file, the write protection for vendor parameters is
		completely disabled. Anybody can change or delete
		these parameters.

		Alternatively, if you #define _both_ CONFIG_ETHADDR
		_and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
		Ethernet address is installed in the environment,
		which can be changed exactly ONCE by the user. [The
		serial# is unaffected by this, i. e. it remains
		read-only.]

		The same can be accomplished in a more flexible way
		for any variable by configuring the type of access
		to allow for those variables in the ".flags" variable
		or define CONFIG_ENV_FLAGS_LIST_STATIC.

- Protected RAM:
		CONFIG_PRAM

		Define this variable to enable the reservation of
		"protected RAM", i. e. RAM which is not overwritten
		by U-Boot. Define CONFIG_PRAM to hold the number of
		kB you want to reserve for pRAM. You can overwrite
		this default value by defining an environment
		variable "pram" to the number of kB you want to
		reserve. Note that the board info structure will
		still show the full amount of RAM. If pRAM is
		reserved, a new environment variable "mem" will
		automatically be defined to hold the amount of
		remaining RAM in a form that can be passed as boot
		argument to Linux, for instance like that:

			setenv bootargs ... mem=\${mem}
			saveenv

		This way you can tell Linux not to use this memory,
		either, which results in a memory region that will
		not be affected by reboots.

		*WARNING* If your board configuration uses automatic
		detection of the RAM size, you must make sure that
		this memory test is non-destructive. So far, the
		following board configurations are known to be
		"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.

		Note that this feature has NOT been implemented yet
		for the "hush" shell.


		CONFIG_SYS_HUSH_PARSER

		Define this variable to enable the "hush" shell (from
		Busybox) as command line interpreter, thus enabling
		powerful command line syntax like
		if...then...else...fi conditionals or `&&' and '||'
		constructs ("shell scripts").

		If undefined, you get the old, much simpler behaviour
		with a somewhat smaller memory footprint.


		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.

- Commandline Editing and History:
		CONFIG_CMDLINE_EDITING

		Enable editing and History functions for interactive
		commandline 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
		intialised 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').

- 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 - support SHA1 hashing
		CONFIG_SHA256 - support SHA256 hashing

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

- 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

- 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.

- 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_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_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_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_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_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_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_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.

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_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_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"
		enviroment 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_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 enviroment 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_SYS_SYM_OFFSETS
	This is set by architectures that use offsets for link symbols
	instead of absolute values. So bss_start is obtained using an
	offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
	directly. You should not need to touch this setting.

- 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
	   for U-Boot code. It should be pointed out that this is
	   STRONGLY DISCOURAGED from a robustness point of view:
	   updating the environment in flash makes it always
	   necessary to erase the WHOLE sector. If something goes
	   wrong before the contents has been restored from a copy in
	   RAM, your target system will be dead.

	- CONFIG_ENV_ADDR_REDUND
	  CONFIG_ENV_SIZE_REDUND

	   These settings describe a second storage area used to hold
	   a redundant copy of the environment data, so that there is
	   a valid backup copy in case there is a power failure during
	   a "saveenv" operation.

BE CAREFUL! Any changes to the flash layout, and some changes to the
source code will make it necessary to adapt <board>/u-boot.lds*
accordingly!


- CONFIG_ENV_IS_IN_NVRAM:

	Define this if you have some non-volatile memory device
	(NVRAM, battery buffered SRAM) which you want to use for the
	environment.

	- CONFIG_ENV_ADDR:
	- CONFIG_ENV_SIZE:

	  These two #defines are used to determine the memory area you
	  want to use for environment. It is assumed that this memory
	  can just be read and written to, without any special
	  provision.

BE CAREFUL! The first access to the environment happens quite early
in U-Boot initalization (when we try to get the setting of for the
console baudrate). You *MUST* have mapped your NVRAM area then, or
U-Boot will hang.

Please note that even with NVRAM we still use a copy of the
environment in RAM: we could work on NVRAM directly, but we want to
keep settings there always unmodified except somebody uses "saveenv"
to save the current settings.


- CONFIG_ENV_IS_IN_EEPROM:

	Use this if you have an EEPROM or similar serial access
	device and a driver for it.

	- CONFIG_ENV_OFFSET:
	- CONFIG_ENV_SIZE:

	  These two #defines specify the offset and size of the
	  environment area within the total memory of your EEPROM.

	- CONFIG_SYS_I2C_EEPROM_ADDR:
	  If defined, specified the chip address of the EEPROM device.
	  The default address is zero.

	- CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
	  If defined, the number of bits used to address bytes in a
	  single page in the EEPROM device.  A 64 byte page, for example
	  would require six bits.

	- CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
	  If defined, the number of milliseconds to delay between
	  page writes.	The default is zero milliseconds.

	- CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
	  The length in bytes of the EEPROM memory array address.  Note
	  that this is NOT the chip address length!

	- CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
	  EEPROM chips that implement "address overflow" are ones
	  like Catalyst 24WC04/08/16 which has 9/10/11 bits of
	  address and the extra bits end up in the "chip address" bit
	  slots. This makes a 24WC08 (1Kbyte) chip look like four 256
	  byte chips.

	  Note that we consider the length of the address field to
	  still be one byte because the extra address bits are hidden
	  in the chip address.

	- CONFIG_SYS_EEPROM_SIZE:
	  The size in bytes of the EEPROM device.

	- CONFIG_ENV_EEPROM_IS_ON_I2C
	  define this, if you have I2C and SPI activated, and your
	  EEPROM, which holds the environment, is on the I2C bus.

	- CONFIG_I2C_ENV_EEPROM_BUS
	  if you have an Environment on an EEPROM reached over
	  I2C muxes, you can define here, how to reach this
	  EEPROM. For example:

	  #define CONFIG_I2C_ENV_EEPROM_BUS	  "pca9547:70:d\0"

	  EEPROM which holds the environment, is reached over
	  a pca9547 i2c mux with address 0x70, channel 3.

- CONFIG_ENV_IS_IN_DATAFLASH:

	Define this if you have a DataFlash memory device which you
	want to use for the environment.

	- CONFIG_ENV_OFFSET:
	- CONFIG_ENV_ADDR:
	- CONFIG_ENV_SIZE:

	  These three #defines specify the offset and size of the
	  environment area within the total memory of your DataFlash placed
	  at the specified address.

- CONFIG_ENV_IS_IN_REMOTE:

	Define this if you have a remote memory space which you
	want to use for the local device's environment.

	- CONFIG_ENV_ADDR:
	- CONFIG_ENV_SIZE:

	  These two #defines specify the address and size of the
	  environment area within the remote memory space. The
	  local device can get the environment from remote memory
	  space by SRIO or PCIE links.

BE CAREFUL! For some special cases, the local device can not use
"saveenv" command. For example, the local device will get the
environment stored in a remote NOR flash by SRIO or PCIE link,
but it can not erase, write this NOR flash by SRIO or PCIE interface.

- CONFIG_ENV_IS_IN_NAND:

	Define this if you have a NAND device which you want to use
	for the environment.

	- CONFIG_ENV_OFFSET:
	- CONFIG_ENV_SIZE:

	  These two #defines specify the offset and size of the environment
	  area within the first NAND device.  CONFIG_ENV_OFFSET must be
	  aligned to an erase block boundary.

	- CONFIG_ENV_OFFSET_REDUND (optional):

	  This setting describes a second storage area of CONFIG_ENV_SIZE
	  size used to hold a redundant copy of the environment data, so
	  that there is a valid backup copy in case there is a power failure
	  during a "saveenv" operation.	 CONFIG_ENV_OFFSET_RENDUND must be
	  aligned to an erase block boundary.

	- CONFIG_ENV_RANGE (optional):

	  Specifies the length of the region in which the environment
	  can be written.  This should be a multiple of the NAND device's
	  block size.  Specifying a range with more erase blocks than
	  are needed to hold CONFIG_ENV_SIZE allows bad blocks within
	  the range to be avoided.

	- CONFIG_ENV_OFFSET_OOB (optional):

	  Enables support for dynamically retrieving the offset of the
	  environment from block zero's out-of-band data.  The
	  "nand env.oob" command can be used to record this offset.
	  Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
	  using CONFIG_ENV_OFFSET_OOB.

- CONFIG_NAND_ENV_DST

	Defines address in RAM to which the nand_spl code should copy the
	environment. If redundant environment is used, it will be copied to
	CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.

- CONFIG_ENV_IS_IN_UBI:

	Define this if you have an UBI volume that you want to use for the
	environment.  This has the benefit of wear-leveling the environment
	accesses, which is important on NAND.

	- CONFIG_ENV_UBI_PART:

	  Define this to a string that is the mtd partition containing the UBI.

	- CONFIG_ENV_UBI_VOLUME:

	  Define this to the name of the volume that you want to store the
	  environment in.

	- CONFIG_ENV_UBI_VOLUME_REDUND:

	  Define this to the name of another volume to store a second copy of
	  the environment in.  This will enable redundant environments in UBI.
	  It is assumed that both volumes are in the same MTD partition.

	- CONFIG_UBI_SILENCE_MSG
	- CONFIG_UBIFS_SILENCE_MSG

	  You will probably want to define these to avoid a really noisy system
	  when storing the env in UBI.

- CONFIG_SYS_SPI_INIT_OFFSET

	Defines offset to the initial SPI buffer area in DPRAM. The
	area is used at an early stage (ROM part) if the environment
	is configured to reside in the SPI EEPROM: We need a 520 byte
	scratch DPRAM area. It is used between the two initialization
	calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
	to be a good choice since it makes it far enough from the
	start of the data area as well as from the stack pointer.

Please note that the environment is read-only until the monitor
has been relocated to RAM and a RAM copy of the environment has been
created; also, when using EEPROM you will have to use getenv_f()
until then to read environment variables.

The environment is protected by a CRC32 checksum. Before the monitor
is relocated into RAM, as a result of a bad CRC you will be working
with the compiled-in default environment - *silently*!!! [This is
necessary, because the first environment variable we need is the
"baudrate" setting for the console - if we have a bad CRC, we don't
have any device yet where we could complain.]

Note: once the monitor has been relocated, then it will complain if
the default environment is used; a new CRC is computed as soon as you
use the "saveenv" command to store a valid environment.

- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
		Echo the inverted Ethernet link state to the fault LED.

		Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
		      also needs to be defined.

- CONFIG_SYS_FAULT_MII_ADDR:
		MII address of the PHY to check for the Ethernet link state.

- CONFIG_NS16550_MIN_FUNCTIONS:
		Define this if you desire to only have use of the NS16550_init
		and NS16550_putc functions for the serial driver located at
		drivers/serial/ns16550.c.  This option is useful for saving
		space for already greatly restricted images, including but not
		limited to NAND_SPL configurations.

- CONFIG_DISPLAY_BOARDINFO
		Display information about the board that U-Boot is running on
		when U-Boot starts up. The board function checkboard() is called
		to do this.

- CONFIG_DISPLAY_BOARDINFO_LATE
		Similar to the previous option, but display this information
		later, once stdio is running and output goes to the LCD, if
		present.

Low Level (hardware related) configuration options:
---------------------------------------------------

- CONFIG_SYS_CACHELINE_SIZE:
		Cache Line Size of the CPU.

- CONFIG_SYS_DEFAULT_IMMR:
		Default address of the IMMR after system reset.

		Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
		and RPXsuper) to be able to adjust the position of
		the IMMR register after a reset.

- CONFIG_SYS_CCSRBAR_DEFAULT:
		Default (power-on reset) physical address of CCSR on Freescale
		PowerPC SOCs.

- CONFIG_SYS_CCSRBAR:
		Virtual address of CCSR.  On a 32-bit build, this is typically
		the same value as CONFIG_SYS_CCSRBAR_DEFAULT.

		CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
		for cross-platform code that uses that macro instead.

- CONFIG_SYS_CCSRBAR_PHYS:
		Physical address of CCSR.  CCSR can be relocated to a new
		physical address, if desired.  In this case, this macro should
		be set to that address.	 Otherwise, it should be set to the
		same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
		is typically relocated on 36-bit builds.  It is recommended
		that this macro be defined via the _HIGH and _LOW macros:

		#define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
			* 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)

- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
		Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS.	This value is typically
		either 0 (32-bit build) or 0xF (36-bit build).	This macro is
		used in assembly code, so it must not contain typecasts or
		integer size suffixes (e.g. "ULL").

- CONFIG_SYS_CCSRBAR_PHYS_LOW:
		Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS.  This macro is
		used in assembly code, so it must not contain typecasts or
		integer size suffixes (e.g. "ULL").

- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
		If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
		forced to a value that ensures that CCSR is not relocated.

- Floppy Disk Support:
		CONFIG_SYS_FDC_DRIVE_NUMBER

		the default drive number (default value 0)

		CONFIG_SYS_ISA_IO_STRIDE

		defines the spacing between FDC chipset registers
		(default value 1)

		CONFIG_SYS_ISA_IO_OFFSET

		defines the offset of register from address. It
		depends on which part of the data bus is connected to
		the FDC chipset. (default value 0)

		If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
		CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
		default value.

		if CONFIG_SYS_FDC_HW_INIT is defined, then the function
		fdc_hw_init() is called at the beginning of the FDC
		setup. fdc_hw_init() must be provided by the board
		source code. It is used to make hardware dependant
		initializations.

- CONFIG_IDE_AHB:
		Most IDE controllers were designed to be connected with PCI
		interface. Only few of them were designed for AHB interface.
		When software is doing ATA command and data transfer to
		IDE devices through IDE-AHB controller, some additional
		registers accessing to these kind of IDE-AHB controller
		is requierd.

- CONFIG_SYS_IMMR:	Physical address of the Internal Memory.
		DO NOT CHANGE unless you know exactly what you're
		doing! (11-4) [MPC8xx/82xx systems only]

- CONFIG_SYS_INIT_RAM_ADDR:

		Start address of memory area that can be used for
		initial data and stack; please note that this must be
		writable memory that is working WITHOUT special
		initialization, i. e. you CANNOT use normal RAM which
		will become available only after programming the
		memory controller and running certain initialization
		sequences.

		U-Boot uses the following memory types:
		- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
		- MPC824X: data cache
		- PPC4xx:  data cache

- CONFIG_SYS_GBL_DATA_OFFSET:

		Offset of the initial data structure in the memory
		area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
		CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
		data is located at the end of the available space
		(sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
		CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
		below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
		CONFIG_SYS_GBL_DATA_OFFSET) downward.

	Note:
		On the MPC824X (or other systems that use the data
		cache for initial memory) the address chosen for
		CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
		point to an otherwise UNUSED address space between
		the top of RAM and the start of the PCI space.

- CONFIG_SYS_SIUMCR:	SIU Module Configuration (11-6)

- CONFIG_SYS_SYPCR:	System Protection Control (11-9)

- CONFIG_SYS_TBSCR:	Time Base Status and Control (11-26)

- CONFIG_SYS_PISCR:	Periodic Interrupt Status and Control (11-31)

- CONFIG_SYS_PLPRCR:	PLL, Low-Power, and Reset Control Register (15-30)

- CONFIG_SYS_SCCR:	System Clock and reset Control Register (15-27)

- CONFIG_SYS_OR_TIMING_SDRAM:
		SDRAM timing

- CONFIG_SYS_MAMR_PTA:
		periodic timer for refresh

- CONFIG_SYS_DER:	Debug Event Register (37-47)

- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
  CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
  CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
  CONFIG_SYS_BR1_PRELIM:
		Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)

- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
  CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
  CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
		Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)

- CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
  CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
		Machine Mode Register and Memory Periodic Timer
		Prescaler definitions (SDRAM timing)

- CONFIG_SYS_I2C_UCODE_PATCH,