GitHub - viaembedded/vab820-uboot-bsp: VIA VAB/AMOS-820 u-boot tree; the "via_*" branches containing modifications on top of the Freescale U-Boot tree

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fs		fs
include		include
lib		lib
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# # (C) Copyright 2000 - 2011 # 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. 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_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. - 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. - 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, board/eltec/bab7xx)	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 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 - Boot Delay:	CONFIG_BOOTDELAY - in seconds	Delay before automatically booting the default image;	set to -1 to disable autoboot.	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_EXPORTENV	* export the environment	CONFIG_CMD_SAVEENV saveenv	CONFIG_CMD_FDC	* Floppy Disk Support	CONFIG_CMD_FAT	* FAT partition support	CONFIG_CMD_FDOS	* Dos diskette Support	CONFIG_CMD_FLASH flinfo, erase, protect	CONFIG_CMD_FPGA FPGA device initialization support	CONFIG_CMD_GO	* the 'go' command (exec code)	CONFIG_CMD_GREPENV	* search environment	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 found images	CONFIG_CMD_IMMAP	* IMMR dump support	CONFIG_CMD_IMPORTENV	* import an environment	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_LOADB loadb	CONFIG_CMD_LOADS loads	CONFIG_CMD_MD5SUM print md5 message digest (requires CONFIG_CMD_MEMORY and CONFIG_MD5)	CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base, loop, loopw, 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_REGINFO	* Register dump	CONFIG_CMD_RUN run command in env variable	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_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	CONFIG_CMD_USB	* USB support	CONFIG_CMD_CDP	* Cisco Discover Protocol support	CONFIG_CMD_FSL	* 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.	This variable is readonly. - 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 Support:	CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION	and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION	If IDE or SCSI support is enabled (CONFIG_CMD_IDE or	CONFIG_CMD_SCSI) you must configure support for at	least one 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) - 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_DRIVER_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_DRIVER_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. - 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 - 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_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 - 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 - 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	Support for saving memory data as a file	in FAT formatted partition - 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. - 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. - 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_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 - 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. - 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_SERVERIP - TFTP server will be the serverip	environment variable, not the BOOTP server.	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. - 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.] - 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":	ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,	HERMES, IP860, RPXlite, LWMON, LANTEC,	FLAGADM, TQM8260 - 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. - 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. - DataFlash Support:	CONFIG_HAS_DATAFLASH	Defining this option enables DataFlash features and	allows to read/write in Dataflash via the standard	commands cp, md... - 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. - 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: 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 - 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.	Then system will reserve the frame buffer address to	defined address instead of lcd_setmem (this function	grabs the memory for frame buffer by panel's 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. - SPL framework	CONFIG_SPL	Enable building of SPL globally.	CONFIG_SPL_TEXT_BASE	TEXT_BASE for linking the SPL binary.	CONFIG_SPL_LDSCRIPT	LDSCRIPT for linking the SPL binary.	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_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_FAT_SUPPORT	Support for fs/fat/libfat.o in SPL binary	CONFIG_SPL_LIBGENERIC_SUPPORT	Support for lib/libgeneric.o in SPL binary 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_TFTP_LOADADDR:	Default load address for network file downloads - 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. 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_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_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. 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, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:	enable I2C microcode relocation patch (MPC8xx);	define relocation offset in DPRAM [DSP2] - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:	enable SMC microcode relocation patch (MPC8xx);	define relocation offset in DPRAM [SMC1] - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:	enable SPI microcode relocation patch (MPC8xx);	define relocation offset in DPRAM [SCC4] - CONFIG_SYS_USE_OSCCLK:	Use OSCM clock mode on MBX8xx board. Be careful,	wrong setting might damage your board. Read	doc/README.MBX before setting this variable! - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)	Offset of the bootmode word in DPRAM used by post	(Power On Self Tests). This definition overrides	#define'd default value in commproc.h resp.	cpm_8260.h. - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL, CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS, CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START, CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL, CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE, CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)	Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set. - CONFIG_PCI_DISABLE_PCIE:	Disable PCI-Express on systems where it is supported but not	required. - CONFIG_SYS_SRIO:	Chip has SRIO or not - CONFIG_SRIO1:	Board has SRIO 1 port available - CONFIG_SRIO2:	Board has SRIO 2 port available - CONFIG_SYS_SRIOn_MEM_VIRT:	Virtual Address of SRIO port 'n' memory region - CONFIG_SYS_SRIOn_MEM_PHYS:	Physical Address of SRIO port 'n' memory region - CONFIG_SYS_SRIOn_MEM_SIZE:	Size of SRIO port 'n' memory region - CONFIG_SYS_NDFC_16	Defined to tell the NDFC that the NAND chip is using a	16 bit bus. - CONFIG_SYS_NDFC_EBC0_CFG	Sets the EBC0_CFG register for the NDFC. If not defined	a default value will be used. - CONFIG_SPD_EEPROM	Get DDR timing information from an I2C EEPROM. Common	with pluggable memory modules such as SODIMMs SPD_EEPROM_ADDRESS	I2C address of the SPD EEPROM - CONFIG_SYS_SPD_BUS_NUM	If SPD EEPROM is on an I2C bus other than the first	one, specify here. Note that the value must resolve	to something your driver can deal with. - CONFIG_SYS_DDR_RAW_TIMING	Get DDR timing information from other than SPD. Common with	soldered DDR chips onboard without SPD. DDR raw timing	parameters are extracted from datasheet and hard-coded into	header files or board specific files. - CONFIG_FSL_DDR_INTERACTIVE	Enable interactive DDR debugging. See doc/README.fsl-ddr. - CONFIG_SYS_83XX_DDR_USES_CS0	Only for 83xx systems. If specified, then DDR should	be configured using CS0 and CS1 instead of CS2 and CS3. - CONFIG_ETHER_ON_FEC[12]	Define to enable FEC[12] on a 8xx series processor. - CONFIG_FEC[12]_PHY	Define to the hardcoded PHY address which corresponds	to the given FEC; i. e.	#define CONFIG_FEC1_PHY 4	means that the PHY with address 4 is connected to FEC1	When set to -1, means to probe for first available. - CONFIG_FEC[12]_PHY_NORXERR	The PHY does not have a RXERR line (RMII only).	(so program the FEC to ignore it). - CONFIG_RMII	Enable RMII mode for all FECs.	Note that this is a global option, we can't	have one FEC in standard MII mode and another in RMII mode. - CONFIG_CRC32_VERIFY	Add a verify option to the crc32 command.	The syntax is:	=> crc32 -v <address> <count> <crc32>	Where address/count indicate a memory area	and crc32 is the correct crc32 which the	area should have. - CONFIG_LOOPW	Add the "loopw" memory command. This only takes effect if	the memory commands are activated globally (CONFIG_CMD_MEM). - CONFIG_MX_CYCLIC	Add the "mdc" and "mwc" memory commands. These are cyclic	"md/mw" commands.	Examples:	=> mdc.b 10 4 500	This command will print 4 bytes (10,11,12,13) each 500 ms.	=> mwc.l 100 12345678 10	This command will write 12345678 to address 100 all 10 ms.	This only takes effect if the memory commands are activated	globally (CONFIG_CMD_MEM). - CONFIG_SKIP_LOWLEVEL_INIT	[ARM, NDS32, MIPS only] If this variable is defined, then certain	low level initializations (like setting up the memory	controller) are omitted and/or U-Boot does not	relocate itself into RAM.	Normally this variable MUST NOT be defined. The only	exception is when U-Boot is loaded (to RAM) by some	other boot loader or by a debugger which performs	these initializations itself. - CONFIG_SPL_BUILD	Modifies the behaviour of start.S when compiling a loader	that is executed before the actual U-Boot. E.g. when	compiling a NAND SPL. - CONFIG_SYS_NAND_HW_ECC_OOBFIRST	define this, if you want to read first the oob data	and then the data. This is used for example on	davinci plattforms. - CONFIG_USE_ARCH_MEMCPY CONFIG_USE_ARCH_MEMSET	If these options are used a optimized version of memcpy/memset will	be used if available. These functions may be faster under some	conditions but may increase the binary size. Building the Software: ====================== Building U-Boot has been tested in several native build environments and in many different cross environments. Of course we cannot support all possibly existing versions of cross development tools in all (potentially obsolete) versions. In case of tool chain problems we recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK) which is extensively used to build and test U-Boot. If you are not using a native environment, it is assumed that you have GNU cross compiling tools available in your path. In this case, you must set the environment variable CROSS_COMPILE in your shell. Note that no changes to the Makefile or any other source files are necessary. For example using the ELDK on a 4xx CPU, please enter:	$ CROSS_COMPILE=ppc_4xx-	$ export CROSS_COMPILE Note: If you wish to generate Windows versions of the utilities in the tools directory you can use the MinGW toolchain (http://www.mingw.org). Set your HOST tools to the MinGW toolchain and execute 'make tools'. For example: $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools Binaries such as tools/mkimage.exe will be created which can be executed on computers running Windows. U-Boot is intended to be simple to build. After installing the sources you must configure U-Boot for one specific board type. This is done by typing:	make NAME_config where "NAME_config" is the name of one of the existing configu- rations; see the main Makefile for supported names. Note: for some board special configuration names may exist; check if additional information is available from the board vendor; for instance, the TQM823L systems are available without (standard) or with LCD support. You can select such additional "features" when choosing the configuration, i. e. make TQM823L_config	- will configure for a plain TQM823L, i. e. no LCD support make TQM823L_LCD_config	- will configure for a TQM823L with U-Boot console on LCD etc. Finally, type "make all", and you should get some working U-Boot images ready for download to / installation on your system: - "u-boot.bin" is a raw binary image - "u-boot" is an image in ELF binary format - "u-boot.srec" is in Motorola S-Record format By default the build is performed locally and the objects are saved in the source directory. One of the two methods can be used to change this behavior and build U-Boot to some external directory: 1. Add O= to the make command line invocations:	make O=/tmp/build distclean	make O=/tmp/build NAME_config	make O=/tmp/build all 2. Set environment variable BUILD_DIR to point to the desired location:	export BUILD_DIR=/tmp/build	make distclean	make NAME_config	make all Note that the command line "O=" setting overrides the BUILD_DIR environment variable. Please be aware that the Makefiles assume you are using GNU make, so for instance on NetBSD you might need to use "gmake" instead of native "make". If the system board that you have is not listed, then you will need to port U-Boot to your hardware platform. To do this, follow these steps: 1. Add a new configuration option for your board to the toplevel "Makefile" and to the "MAKEALL" script, using the existing entries as examples. Note that here and at many other places boards and other names are listed in alphabetical sort order. Please keep this order. 2. Create a new directory to hold your board specific code. Add any files you need. In your board directory, you will need at least the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds". 3. Create a new configuration file "include/configs/<board>.h" for your board 3. If you're porting U-Boot to a new CPU, then also create a new directory to hold your CPU specific code. Add any files you need. 4. Run "make <board>_config" with your new name. 5. Type "make", and you should get a working "u-boot.srec" file to be installed on your target system. 6. Debug and solve any problems that might arise. [Of course, this last step is much harder than it sounds.] Testing of U-Boot Modifications, Ports to New Hardware, etc.: ============================================================== If you have modified U-Boot sources (for instance added a new board or support for new devices, a new CPU, etc.) you are expected to provide feedback to the other developers. The feedback normally takes the form of a "patch", i. e. a context diff against a certain (latest official or latest in the git repository) version of U-Boot sources. But before you submit such a patch, please verify that your modifi- cation did not break existing code. At least make sure that *ALL* of the supported boards compile WITHOUT ANY compiler warnings. To do so, just run the "MAKEALL" script, which will configure and build U-Boot for ALL supported system. Be warned, this will take a while. You can select which (cross) compiler to use by passing a `CROSS_COMPILE' environment variable to the script, i. e. to use the ELDK cross tools you can type	CROSS_COMPILE=ppc_8xx- MAKEALL or to build on a native PowerPC system you can type	CROSS_COMPILE=' ' MAKEALL When using the MAKEALL script, the default behaviour is to build U-Boot in the source directory. This location can be changed by setting the BUILD_DIR environment variable. Also, for each target built, the MAKEALL script saves two log files (<target>.ERR and <target>.MAKEALL) in the <source dir>/LOG directory. This default location can be changed by setting the MAKEALL_LOGDIR environment variable. For example:	export BUILD_DIR=/tmp/build	export MAKEALL_LOGDIR=/tmp/log	CROSS_COMPILE=ppc_8xx- MAKEALL With the above settings build objects are saved in the /tmp/build, log files are saved in the /tmp/log and the source tree remains clean during the whole build process. See also "U-Boot Porting Guide" below. Monitor Commands - Overview: ============================ go	- start application at address 'addr' run	- run commands in an environment variable bootm	- boot application image from memory bootp	- boot image via network using BootP/TFTP protocol tftpboot- boot image via network using TFTP protocol and env variables "ipaddr" and "serverip" (and eventually "gatewayip") tftpput - upload a file via network using TFTP protocol rarpboot- boot image via network using RARP/TFTP protocol diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' loads	- load S-Record file over serial line loadb	- load binary file over serial line (kermit mode) md	- memory display mm	- memory modify (auto-incrementing) nm	- memory modify (constant address) mw	- memory write (fill) cp	- memory copy cmp	- memory compare crc32	- checksum calculation i2c	- I2C sub-system sspi	- SPI utility commands base	- print or set address offset printenv- print environment variables setenv	- set environment variables saveenv - save environment variables to persistent storage protect - enable or disable FLASH write protection erase	- erase FLASH memory flinfo	- print FLASH memory information bdinfo	- print Board Info structure iminfo	- print header information for application image coninfo - print console devices and informations ide	- IDE sub-system loop	- infinite loop on address range loopw	- infinite write loop on address range mtest	- simple RAM test icache	- enable or disable instruction cache dcache	- enable or disable data cache reset	- Perform RESET of the CPU echo	- echo args to console version - print monitor version help	- print online help ?	- alias for 'help' Monitor Commands - Detailed Description: ======================================== TODO. For now: just type "help <command>". Environment Variables: ====================== U-Boot supports user configuration using Environment Variables which can be made persistent by saving to Flash memory. Environment Variables are set using "setenv", printed using "printenv", and saved to Flash using "saveenv". Using "setenv" without a value can be used to delete a variable from the environment. As long as you don't save the environment you are working with an in-memory copy. In case the Flash area containing the environment is erased by accident, a default environment is provided. Some configuration options can be set using Environment Variables. List of environment variables (most likely not complete): baudrate	- see CONFIG_BAUDRATE bootdelay	- see CONFIG_BOOTDELAY bootcmd	- see CONFIG_BOOTCOMMAND bootargs	- Boot arguments when booting an RTOS image bootfile	- Name of the image to load with TFTP bootm_low	- Memory range available for image processing in the bootm command can be restricted. This variable is given as a hexadecimal number and defines lowest address allowed for use by the bootm command. See also "bootm_size" environment variable. Address defined by "bootm_low" is also the base of the initial memory mapping for the Linux kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and bootm_mapsize. bootm_mapsize - Size of the initial memory mapping for the Linux kernel. This variable is given as a hexadecimal number and it defines the size of the memory region starting at base address bootm_low that is accessible by the Linux kernel during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used as the default value if it is defined, and bootm_size is used otherwise. bootm_size	- Memory range available for image processing in the bootm command can be restricted. This variable is given as a hexadecimal number and defines the size of the region allowed for use by the bootm command. See also "bootm_low" environment variable. updatefile	- Location of the software update file on a TFTP server, used by the automatic software update feature. Please refer to documentation in doc/README.update for more details. autoload	- if set to "no" (any string beginning with 'n'), "bootp" will just load perform a lookup of the configuration from the BOOTP server, but not try to load any image using TFTP autostart	- if set to "yes", an image loaded using the "bootp", "rarpboot", "tftpboot" or "diskboot" commands will be automatically started (by internally calling "bootm") If set to "no", a standalone image passed to the "bootm" command will be copied to the load address (and eventually uncompressed), but NOT be started. This can be used to load and uncompress arbitrary data. fdt_high	- if set this restricts the maximum address that the flattened device tree will be copied into upon boot. If this is set to the special value 0xFFFFFFFF then the fdt will not be copied at all on boot. For this to work it must reside in writable memory, have sufficient padding on the end of it for u-boot to add the information it needs into it, and the memory must be accessible by the kernel. fdtcontroladdr- if set this is the address of the control flattened device tree used by U-Boot when CONFIG_OF_CONTROL is defined. i2cfast	- (PPC405GP|PPC405EP only) if set to 'y' configures Linux I2C driver for fast mode (400kHZ). This environment variable is used in initialization code. So, for changes to be effective it must be saved and board must be reset. initrd_high	- restrict positioning of initrd images: If this variable is not set, initrd images will be copied to the highest possible address in RAM; this is usually what you want since it allows for maximum initrd size. If for some reason you want to make sure that the initrd image is loaded below the CONFIG_SYS_BOOTMAPSZ limit, you can set this environment variable to a value of "no" or "off" or "0". Alternatively, you can set it to a maximum upper address to use (U-Boot will still check that it does not overwrite the U-Boot stack and data). For instance, when you have a system with 16 MB RAM, and want to reserve 4 MB from use by Linux, you can do this by adding "mem=12M" to the value of the "bootargs" variable. However, now you must make sure that the initrd image is placed in the first 12 MB as well - this can be done with setenv initrd_high 00c00000 If you set initrd_high to 0xFFFFFFFF, this is an indication to U-Boot that all addresses are legal for the Linux kernel, including addresses in flash memory. In this case U-Boot will NOT COPY the ramdisk at all. This may be useful to reduce the boot time on your system, but requires that this feature is supported by your Linux kernel. ipaddr	- IP address; needed for tftpboot command loadaddr	- Default load address for commands like "bootp", "rarpboot", "tftpboot", "loadb" or "diskboot" loads_echo	- see CONFIG_LOADS_ECHO serverip	- TFTP server IP address; needed for tftpboot command bootretry	- see CONFIG_BOOT_RETRY_TIME bootdelaykey	- see CONFIG_AUTOBOOT_DELAY_STR bootstopkey	- see CONFIG_AUTOBOOT_STOP_STR ethprime	- controls which interface is used first. ethact	- controls which interface is currently active. For example you can do the following => setenv ethact FEC => ping 192.168.0.1 # traffic sent on FEC => setenv ethact SCC => ping 10.0.0.1 # traffic sent on SCC ethrotate	- When set to "no" U-Boot does not go through all available network interfaces. It just stays at the currently selected interface. netretry	- When set to "no" each network operation will either succeed or fail without retrying. When set to "once" the network operation will fail when all the available network interfaces are tried once without success. Useful on scripts which control the retry operation themselves. npe_ucode	- set load address for the NPE microcode tftpsrcport	- If this is set, the value is used for TFTP's UDP source port. tftpdstport	- If this is set, the value is used for TFTP's UDP destination port instead of the Well Know Port 69. tftpblocksize - Block size to use for TFTP transfers; if not set, we use the TFTP server's default block size tftptimeout	- Retransmission timeout for TFTP packets (in milli- seconds, minimum value is 1000 = 1 second). Defines when a packet is considered to be lost so it has to be retransmitted. The default is 5000 = 5 seconds. Lowering this value may make downloads succeed faster in networks with high packet loss rates or with unreliable TFTP servers. vlan	- When set to a value < 4095 the traffic over Ethernet is encapsulated/received over 802.1q VLAN tagged frames. The following image location variables contain the location of images used in booting. The "Image" column gives the role of the image and is not an environment variable name. The other columns are environment variable names. "File Name" gives the name of the file on a TFTP server, "RAM Address" gives the location in RAM the image will be loaded to, and "Flash Location" gives the image's address in NOR flash or offset in NAND flash. *Note* - these variables don't have to be defined for all boards, some boards currenlty use other variables for these purposes, and some boards use these variables for other purposes. Image File Name RAM Address Flash Location ----- --------- ----------- -------------- u-boot u-boot u-boot_addr_r u-boot_addr Linux kernel bootfile kernel_addr_r kernel_addr device tree blob fdtfile fdt_addr_r fdt_addr ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr The following environment variables may be used and automatically updated by the network boot commands ("bootp" and "rarpboot"), depending the information provided by your boot server: bootfile	- see above dnsip	- IP address of your Domain Name Server dnsip2	- IP address of your secondary Domain Name Server gatewayip	- IP address of the Gateway (Router) to use hostname	- Target hostname ipaddr	- see above netmask	- Subnet Mask rootpath	- Pathname of the root filesystem on the NFS server serverip	- see above There are two special Environment Variables: serial#	- contains hardware identification information such as type string and/or serial number ethaddr	- Ethernet address These variables can be set only once (usually during manufacturing of the board). U-Boot refuses to delete or overwrite these variables once they have been set once. Further special Environment Variables: ver	- Contains the U-Boot version string as printed with the "version" command. This variable is readonly (see CONFIG_VERSION_VARIABLE). Please note that changes to some configuration parameters may take only effect after the next boot (yes, that's just like Windoze :-). Command Line Parsing: ===================== There are two different command line parsers available with U-Boot: the old "simple" one, and the much more powerful "hush" shell: Old, simple command line parser: -------------------------------- - supports environment variables (through setenv / saveenv commands) - several commands on one line, separated by ';' - variable substitution using "... ${name} ..." syntax - special characters ('$', ';') can be escaped by prefixing with '\', for example:	setenv bootcmd bootm \${address} - You can also escape text by enclosing in single apostrophes, for example:	setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off' Hush shell: ----------- - similar to Bourne shell, with control structures like if...then...else...fi, for...do...done; while...do...done, until...do...done, ... - supports environment ("global") variables (through setenv / saveenv commands) and local shell variables (through standard shell syntax "name=value"); only environment variables can be used with "run" command General rules: -------------- (1) If a command line (or an environment variable executed by a "run" command) contains several commands separated by semicolon, and one of these commands fails, then the remaining commands will be executed anyway. (2) If you execute several variables with one call to run (i. e. calling run with a list of variables as arguments), any failing command will cause "run" to terminate, i. e. the remaining variables are not executed. Note for Redundant Ethernet Interfaces: ======================================= Some boards come with redundant Ethernet interfaces; U-Boot supports such configurations and is capable of automatic selection of a "working" interface when needed. MAC assignment works as follows: Network interfaces are numbered eth0, eth1, eth2, ... Corresponding MAC addresses can be stored in the environment as "ethaddr" (=>eth0), "eth1addr" (=>eth1), "eth2addr", ... If the network interface stores some valid MAC address (for instance in SROM), this is used as default address if there is NO correspon- ding setting in the environment; if the corresponding environment variable is set, this overrides the settings in the card; that means: o If the SROM has a valid MAC address, and there is no address in the environment, the SROM's address is used. o If there is no valid address in the SROM, and a definition in the environment exists, then the value from the environment variable is used. o If both the SROM and the environment contain a MAC address, and both addresses are the same, this MAC address is used. o If both the SROM and the environment contain a MAC address, and the addresses differ, the value from the environment is used and a warning is printed. o If neither SROM nor the environment contain a MAC address, an error is raised. If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses will be programmed into hardware as part of the initialization process. This may be skipped by setting the appropriate 'ethmacskip' environment variable. The naming convention is as follows: "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. Image Formats: ============== U-Boot is capable of booting (and performing other auxiliary operations on) images in two formats: New uImage format (FIT) ----------------------- Flexible and powerful format based on Flattened Image Tree -- FIT (similar to Flattened Device Tree). It allows the use of images with multiple components (several kernels, ramdisks, etc.), with contents protected by SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. Old uImage format ----------------- Old image format is based on binary files which can be basically anything, preceded by a special header; see the definitions in include/image.h for details; basically, the header defines the following image properties: * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, LynxOS, pSOS, QNX, RTEMS, INTEGRITY; Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, INTEGRITY). * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86, IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC). * Compression Type (uncompressed, gzip, bzip2) * Load Address * Entry Point * Image Name * Image Timestamp The header is marked by a special Magic Number, and both the header and the data portions of the image are secured against corruption by CRC32 checksums. Linux Support: ============== Although U-Boot should support any OS or standalone application easily, the main focus has always been on Linux during the design of U-Boot. U-Boot includes many features that so far have been part of some special "boot loader" code within the Linux kernel. Also, any "initrd" images to be used are no longer part of one big Linux image; instead, kernel and "initrd" are separate images. This implementation serves several purposes: - the same features can be used for other OS or standalone applications (for instance: using compressed images to reduce the Flash memory footprint) - it becomes much easier to port new Linux kernel versions because lots of low-level, hardware dependent stuff are done by U-Boot - the same Linux kernel image can now be used with different "initrd" images; of course this also means that different kernel images can be run with the same "initrd". This makes testing easier (you don't have to build a new "zImage.initrd" Linux image when you just change a file in your "initrd"). Also, a field-upgrade of the software is easier now. Linux HOWTO: ============ Porting Linux to U-Boot based systems: --------------------------------------- U-Boot cannot save you from doing all the necessary modifications to configure the Linux device drivers for use with your target hardware (no, we don't intend to provide a full virtual machine interface to Linux :-). But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). Just make sure your machine specific header file (for instance include/asm-ppc/tqm8xx.h) includes the same definition of the Board Information structure as we define in include/asm-<arch>/u-boot.h, and make sure that your definition of IMAP_ADDR uses the same value as your U-Boot configuration in CONFIG_SYS_IMMR. Configuring the Linux kernel: ----------------------------- No specific requirements for U-Boot. Make sure you have some root device (initial ramdisk, NFS) for your target system. Building a Linux Image: ----------------------- With U-Boot, "normal" build targets like "zImage" or "bzImage" are not used. If you use recent kernel source, a new build target "uImage" will exist which automatically builds an image usable by U-Boot. Most older kernels also have support for a "pImage" target, which was introduced for our predecessor project PPCBoot and uses a 100% compatible format. Example:	make TQM850L_config	make oldconfig	make dep	make uImage The "uImage" build target uses a special tool (in 'tools/mkimage') to encapsulate a compressed Linux kernel image with header information, CRC32 checksum etc. for use with U-Boot. This is what we are doing: * build a standard "vmlinux" kernel image (in ELF binary format): * convert the kernel into a raw binary image:	${CROSS_COMPILE}-objcopy -O binary \ -R .note -R .comment \ -S vmlinux linux.bin * compress the binary image:	gzip -9 linux.bin * package compressed binary image for U-Boot:	mkimage -A ppc -O linux -T kernel -C gzip \	-a 0 -e 0 -n "Linux Kernel Image" \	-d linux.bin.gz uImage The "mkimage" tool can also be used to create ramdisk images for use with U-Boot, either separated from the Linux kernel image, or combined into one file. "mkimage" encapsulates the images with a 64 byte header containing information about target architecture, operating system, image type, compression method, entry points, time stamp, CRC32 checksums, etc. "mkimage" can be called in two ways: to verify existing images and print the header information, or to build new images. In the first form (with "-l" option) mkimage lists the information contained in the header of an existing U-Boot image; this includes checksum verification:	tools/mkimage -l image -l ==> list image header information The second form (with "-d" option) is used to build a U-Boot image from a "data file" which is used as image payload:	tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ -n name -d data_file image -A ==> set architecture to 'arch' -O ==> set operating system to 'os' -T ==> set image type to 'type' -C ==> set compression type 'comp' -a ==> set load address to 'addr' (hex) -e ==> set entry point to 'ep' (hex) -n ==> set image name to 'name' -d ==> use image data from 'datafile' Right now, all Linux kernels for PowerPC systems use the same load address (0x00000000), but the entry point address depends on the kernel version: - 2.2.x kernels have the entry point at 0x0000000C, - 2.3.x and later kernels have the entry point at 0x00000000. So a typical call to build a U-Boot image would read:	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \	> -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \	> examples/uImage.TQM850L	Image Name: 2.4.4 kernel for TQM850L	Created: Wed Jul 19 02:34:59 2000	Image Type: PowerPC Linux Kernel Image (gzip compressed)	Data Size: 335725 Bytes = 327.86 kB = 0.32 MB	Load Address: 0x00000000	Entry Point: 0x00000000 To verify the contents of the image (or check for corruption):	-> tools/mkimage -l examples/uImage.TQM850L	Image Name: 2.4.4 kernel for TQM850L	Created: Wed Jul 19 02:34:59 2000	Image Type: PowerPC Linux Kernel Image (gzip compressed)	Data Size: 335725 Bytes = 327.86 kB = 0.32 MB	Load Address: 0x00000000	Entry Point: 0x00000000 NOTE: for embedded systems where boot time is critical you can trade speed for memory and install an UNCOMPRESSED image instead: this needs more space in Flash, but boots much faster since it does not need to be uncompressed:	-> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz	-> tools/mkimage -n '2.4.4 kernel for TQM850L' \	> -A ppc -O linux -T kernel -C none -a 0 -e 0 \	> -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \	> examples/uImage.TQM850L-uncompressed	Image Name: 2.4.4 kernel for TQM850L	Created: Wed Jul 19 02:34:59 2000	Image Type: PowerPC Linux Kernel Image (uncompressed)	Data Size: 792160 Bytes = 773.59 kB = 0.76 MB	Load Address: 0x00000000	Entry Point: 0x00000000 Similar you can build U-Boot images from a 'ramdisk.image.gz' file when your kernel is intended to use an initial ramdisk:	-> tools/mkimage -n 'Simple Ramdisk Image' \	> -A ppc -O linux -T ramdisk -C gzip \	> -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd	Image Name: Simple Ramdisk Image	Created: Wed Jan 12 14:01:50 2000	Image Type: PowerPC Linux RAMDisk Image (gzip compressed)	Data Size: 566530 Bytes = 553.25 kB = 0.54 MB	Load Address: 0x00000000	Entry Point: 0x00000000 Installing a Linux Image: ------------------------- To downloading a U-Boot image over the serial (console) interface, you must convert the image to S-Record format:	objcopy -I binary -O srec examples/image examples/image.srec The 'objcopy' does not understand the information in the U-Boot image header, so the resulting S-Record file will be relative to address 0x00000000. To load it to a given address, you need to specify the target address as 'offset' parameter with the 'loads' command. Example: install the image to address 0x40100000 (which on the TQM8xxL is in the first Flash bank):	=> erase 40100000 401FFFFF	.......... done	Erased 8 sectors	=> loads 40100000	## Ready for S-Record download ...	~>examples/image.srec	1 2 3 4 5 6 7 8 9 10 11 12 13 ...	...	15989 15990 15991 15992	[file transfer complete]	[connected]	## Start Addr = 0x00000000 You can check the success of the download using the 'iminfo' command; this includes a checksum verification so you can be sure no data corruption happened:	=> imi 40100000	## Checking Image at 40100000 ... Image Name: 2.2.13 for initrd on TQM850L Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 335725 Bytes = 327 kB = 0 MB Load Address: 00000000 Entry Point: 0000000c Verifying Checksum ... OK Boot Linux: ----------- The "bootm" command is used to boot an application that is stored in memory (RAM or Flash). In case of a Linux kernel image, the contents of the "bootargs" environment variable is passed to the kernel as parameters. You can check and modify this variable using the "printenv" and "setenv" commands:	=> printenv bootargs	bootargs=root=/dev/ram	=> setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2	=> printenv bootargs	bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2	=> bootm 40020000	## Booting Linux kernel at 40020000 ... Image Name: 2.2.13 for NFS on TQM850L Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 381681 Bytes = 372 kB = 0 MB Load Address: 00000000 Entry Point: 0000000c Verifying Checksum ... OK Uncompressing Kernel Image ... OK	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000	Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2	time_init: decrementer frequency = 187500000/60	Calibrating delay loop... 49.77 BogoMIPS	Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]	... If you want to boot a Linux kernel with initial RAM disk, you pass the memory addresses of both the kernel and the initrd image (PPBCOOT format!) to the "bootm" command:	=> imi 40100000 40200000	## Checking Image at 40100000 ... Image Name: 2.2.13 for initrd on TQM850L Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 335725 Bytes = 327 kB = 0 MB Load Address: 00000000 Entry Point: 0000000c Verifying Checksum ... OK	## Checking Image at 40200000 ... Image Name: Simple Ramdisk Image Image Type: PowerPC Linux RAMDisk Image (gzip compressed) Data Size: 566530 Bytes = 553 kB = 0 MB Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK	=> bootm 40100000 40200000	## Booting Linux kernel at 40100000 ... Image Name: 2.2.13 for initrd on TQM850L Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 335725 Bytes = 327 kB = 0 MB Load Address: 00000000 Entry Point: 0000000c Verifying Checksum ... OK Uncompressing Kernel Image ... OK	## Loading RAMDisk Image at 40200000 ... Image Name: Simple Ramdisk Image Image Type: PowerPC Linux RAMDisk Image (gzip compressed) Data Size: 566530 Bytes = 553 kB = 0 MB Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK Loading Ramdisk ... OK	Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000	Boot arguments: root=/dev/ram	time_init: decrementer frequency = 187500000/60	Calibrating delay loop... 49.77 BogoMIPS	...	RAMDISK: Compressed image found at block 0	VFS: Mounted root (ext2 filesystem).	bash# Boot Linux and pass a flat device tree: ----------- First, U-Boot must be compiled with the appropriate defines. See the section titled "Linux Kernel Interface" above for a more in depth explanation. The following is an example of how to start a kernel and pass an updated flat device tree: => print oftaddr oftaddr=0x300000 => print oft oft=oftrees/mpc8540ads.dtb => tftp $oftaddr $oft Speed: 1000, full duplex Using TSEC0 device TFTP from server 192.168.1.1; our IP address is 192.168.1.101 Filename 'oftrees/mpc8540ads.dtb'. Load address: 0x300000 Loading: # done Bytes transferred = 4106 (100a hex) => tftp $loadaddr $bootfile Speed: 1000, full duplex Using TSEC0 device TFTP from server 192.168.1.1; our IP address is 192.168.1.2 Filename 'uImage'. Load address: 0x200000 Loading:############ done Bytes transferred = 1029407 (fb51f hex) => print loadaddr loadaddr=200000 => print oftaddr oftaddr=0x300000 => bootm $loadaddr - $oftaddr ## Booting image at 00200000 ... Image Name: Linux-2.6.17-dirty Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 1029343 Bytes = 1005.2 kB Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK Uncompressing Kernel Image ... OK Booting using flat device tree at 0x300000 Using MPC85xx ADS machine description Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb [snip] More About U-Boot Image Types: ------------------------------ U-Boot supports the following image types: "Standalone Programs" are directly runnable in the environment	provided by U-Boot; it is expected that (if they behave	well) you can continue to work in U-Boot after return from	the Standalone Program. "OS Kernel Images" are usually images of some Embedded OS which	will take over control completely. Usually these programs	will install their own set of exception handlers, device	drivers, set up the MMU, etc. - this means, that you cannot	expect to re-enter U-Boot except by resetting the CPU. "RAMDisk Images" are more or less just data blocks, and their	parameters (address, size) are passed to an OS kernel that is	being started. "Multi-File Images" contain several images, typically an OS	(Linux) kernel image and one or more data images like	RAMDisks. This construct is useful for instance when you want	to boot over the network using BOOTP etc., where the boot	server provides just a single image file, but you want to get	for instance an OS kernel and a RAMDisk image.	"Multi-File Images" start with a list of image sizes, each	image size (in bytes) specified by an "uint32_t" in network	byte order. This list is terminated by an "(uint32_t)0".	Immediately after the terminating 0 follow the images, one by	one, all aligned on "uint32_t" boundaries (size rounded up to	a multiple of 4 bytes). "Firmware Images" are binary images containing firmware (like	U-Boot or FPGA images) which usually will be programmed to	flash memory. "Script files" are command sequences that will be executed by	U-Boot's command interpreter; this feature is especially	useful when you configure U-Boot to use a real shell (hush)	as command interpreter. Standalone HOWTO: ================= One of the features of U-Boot is that you can dynamically load and run "standalone" applications, which can use some resources of U-Boot like console I/O functions or interrupt services. Two simple examples are included with the sources: "Hello World" Demo: ------------------- 'examples/hello_world.c' contains a small "Hello World" Demo application; it is automatically compiled when you build U-Boot. It's configured to run at address 0x00040004, so you can play with it like that:	=> loads	## Ready for S-Record download ...	~>examples/hello_world.srec	1 2 3 4 5 6 7 8 9 10 11 ...	[file transfer complete]	[connected]	## Start Addr = 0x00040004	=> go 40004 Hello World! This is a test.	## Starting application at 0x00040004 ...	Hello World	argc = 7	argv[0] = "40004"	argv[1] = "Hello"	argv[2] = "World!"	argv[3] = "This"	argv[4] = "is"	argv[5] = "a"	argv[6] = "test."	argv[7] = "<NULL>"	Hit any key to exit ...	## Application terminated, rc = 0x0 Another example, which demonstrates how to register a CPM interrupt handler with the U-Boot code, can be found in 'examples/timer.c'. Here, a CPM timer is set up to generate an interrupt every second. The interrupt service routine is trivial, just printing a '.' character, but this is just a demo program. The application can be controlled by the following keys:	? - print current values og the CPM Timer registers	b - enable interrupts and start timer	e - stop timer and disable interrupts	q - quit application	=> loads	## Ready for S-Record download ...	~>examples/timer.srec	1 2 3 4 5 6 7 8 9 10 11 ...	[file transfer complete]	[connected]	## Start Addr = 0x00040004	=> go 40004	## Starting application at 0x00040004 ...	TIMERS=0xfff00980	Using timer 1 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 Hit 'b':	[q, b, e, ?] Set interval 1000000 us	Enabling timer Hit '?':	[q, b, e, ?] ........	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 Hit '?':	[q, b, e, ?] .	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 Hit '?':	[q, b, e, ?] .	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 Hit '?':	[q, b, e, ?] .	tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 Hit 'e':	[q, b, e, ?] ...Stopping timer Hit 'q':	[q, b, e, ?] ## Application terminated, rc = 0x0 Minicom warning: ================ Over time, many people have reported problems when trying to use the "minicom" terminal emulation program for serial download. I (wd) consider minicom to be broken, and recommend not to use it. Under Unix, I recommend to use C-Kermit for general purpose use (and especially for kermit binary protocol download ("loadb" command), and use "cu" for S-Record download ("loads" command). Nevertheless, if you absolutely want to use it try adding this configuration to your "File transfer protocols" section: Name Program	Name U/D FullScr IO-Red. Multi	X kermit /usr/bin/kermit -i -l %l -s Y U Y N N	Y kermit /usr/bin/kermit -i -l %l -r N D Y N N NetBSD Notes: ============= Starting at version 0.9.2, U-Boot supports NetBSD both as host (build U-Boot) and target system (boots NetBSD/mpc8xx). Building requires a cross environment; it is known to work on NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also need gmake since the Makefiles are not compatible with BSD make). Note that the cross-powerpc package does not install include files; attempting to build U-Boot will fail because <machine/ansi.h> is missing. This file has to be installed and patched manually:	# cd /usr/pkg/cross/powerpc-netbsd/include	# mkdir powerpc	# ln -s powerpc machine	# cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h	# ${EDIT} powerpc/ansi.h	## must remove __va_list, _BSD_VA_LIST Native builds *don't* work due to incompatibilities between native and U-Boot include files. Booting assumes that (the first part of) the image booted is a stage-2 loader which in turn loads and then invokes the kernel proper. Loader sources will eventually appear in the NetBSD source tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz Implementation Internals: ========================= The following is not intended to be a complete description of every implementation detail. However, it should help to understand the inner workings of U-Boot and make it easier to port it to custom hardware. Initial Stack, Global Data: --------------------------- The implementation of U-Boot is complicated by the fact that U-Boot starts running out of ROM (flash memory), usually without access to system RAM (because the memory controller is not initialized yet). This means that we don't have writable Data or BSS segments, and BSS is not initialized as zero. To be able to get a C environment working at all, we have to allocate at least a minimal stack. Implementation options for this are defined and restricted by the CPU used: Some CPU models provide on-chip memory (like the IMMR area on MPC8xx and MPC826x processors), on others (parts of) the data cache can be locked as (mis-) used as memory, etc.	Chris Hallinan posted a good summary of these issues to the	U-Boot mailing list:	Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?	From: "Chris Hallinan" <clh@net1plus.com>	Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)	...	Correct me if I'm wrong, folks, but the way I understand it	is this: Using DCACHE as initial RAM for Stack, etc, does not	require any physical RAM backing up the cache. The cleverness	is that the cache is being used as a temporary supply of	necessary storage before the SDRAM controller is setup. It's	beyond the scope of this list to explain the details, but you	can see how this works by studying the cache architecture and	operation in the architecture and processor-specific manuals.	OCM is On Chip Memory, which I believe the 405GP has 4K. It	is another option for the system designer to use as an	initial stack/RAM area prior to SDRAM being available. Either	option should work for you. Using CS 4 should be fine if your	board designers haven't used it for something that would	cause you grief during the initial boot! It is frequently not	used.	CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere	with your processor/board/system design. The default value	you will find in any recent u-boot distribution in	walnut.h should work for you. I'd set it to a value larger	than your SDRAM module. If you have a 64MB SDRAM module, set	it above 400_0000. Just make sure your board has no resources	that are supposed to respond to that address! That code in	start.S has been around a while and should work as is when	you get the config right.	-Chris Hallinan	DS4.COM, Inc. It is essential to remember this, since it has some impact on the C code for the initialization procedures: * Initialized global data (data segment) is read-only. Do not attempt to write it. * Do not use any uninitialized global data (or implicitely initialized as zero data - BSS segment) at all - this is undefined, initiali- zation is performed later (when relocating to RAM). * Stack space is very limited. Avoid big data buffers or things like that. Having only the stack as writable memory limits means we cannot use normal global data to share information beween the code. But it turned out that the implementation of U-Boot can be greatly simplified by making a global data structure (gd_t) available to all functions. We could pass a pointer to this data as argument to _all_ functions, but this would bloat the code. Instead we use a feature of the GCC compiler (Global Register Variables) to share the data: we place a pointer (gd) to the global data into a register which we reserve for this purpose. When choosing a register for such a purpose we are restricted by the relevant (E)ABI specifications for the current architecture, and by GCC's implementation. For PowerPC, the following registers have specific use:	R1:	stack pointer	R2:	reserved for system use	R3-R4:	parameter passing and return values	R5-R10: parameter passing	R13:	small data area pointer	R30:	GOT pointer	R31:	frame pointer	(U-Boot also uses R12 as internal GOT pointer. r12	is a volatile register so r12 needs to be reset when	going back and forth between asm and C) ==> U-Boot will use R2 to hold a pointer to the global data Note: on PPC, we could use a static initializer (since the address of the global data structure is known at compile time), but it turned out that reserving a register results in somewhat smaller code - although the code savings are not that big (on average for all boards 752 bytes for the whole U-Boot image, 624 text + 127 data). On Blackfin, the normal C ABI (except for P3) is followed as documented here: http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface ==> U-Boot will use P3 to hold a pointer to the global data On ARM, the following registers are used:	R0:	function argument word/integer result	R1-R3:	function argument word	R9:	GOT pointer	R10:	stack limit (used only if stack checking if enabled)	R11:	argument (frame) pointer	R12:	temporary workspace	R13:	stack pointer	R14:	link register	R15:	program counter ==> U-Boot will use R8 to hold a pointer to the global data On Nios II, the ABI is documented here: http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf ==> U-Boot will use gp to hold a pointer to the global data Note: on Nios II, we give "-G0" option to gcc and don't use gp to access small data sections, so gp is free. On NDS32, the following registers are used:	R0-R1:	argument/return	R2-R5:	argument	R15:	temporary register for assembler	R16:	trampoline register	R28:	frame pointer (FP)	R29:	global pointer (GP)	R30:	link register (LP)	R31:	stack pointer (SP)	PC:	program counter (PC) ==> U-Boot will use R10 to hold a pointer to the global data NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, or current versions of GCC may "optimize" the code too much. Memory Management: ------------------ U-Boot runs in system state and uses physical addresses, i.e. the MMU is not used either for address mapping nor for memory protection. The available memory is mapped to fixed addresses using the memory controller. In this process, a contiguous block is formed for each memory type (Flash, SDRAM, SRAM), even when it consists of several physical memory banks. U-Boot is installed in the first 128 kB of the first Flash bank (on TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After booting and sizing and initializing DRAM, the code relocates itself to the upper end of DRAM. Immediately below the U-Boot code some memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN configuration setting]. Below that, a structure with global Board Info data is placed, followed by the stack (growing downward). Additionally, some exception handler code is copied to the low 8 kB of DRAM (0x00000000 ... 0x00001FFF). So a typical memory configuration with 16 MB of DRAM could look like this:	0x0000 0000	Exception Vector code :	0x0000 1FFF	0x0000 2000	Free for Application Use : : : :	0x00FB FF20	Monitor Stack (Growing downward)	0x00FB FFAC	Board Info Data and permanent copy of global data	0x00FC 0000	Malloc Arena :	0x00FD FFFF	0x00FE 0000	RAM Copy of Monitor Code	...	eventually: LCD or video framebuffer	...	eventually: pRAM (Protected RAM - unchanged by reset)	0x00FF FFFF	[End of RAM] System Initialization: ---------------------- In the reset configuration, U-Boot starts at the reset entry point (on most PowerPC systems at address 0x00000100). Because of the reset configuration for CS0# this is a mirror of the onboard Flash memory. To be able to re-map memory U-Boot then jumps to its link address. To be able to implement the initialization code in C, a (small!) initial stack is set up in the internal Dual Ported RAM (in case CPUs which provide such a feature like MPC8xx or MPC8260), or in a locked part of the data cache. After that, U-Boot initializes the CPU core, the caches and the SIU. Next, all (potentially) available memory banks are mapped using a preliminary mapping. For example, we put them on 512 MB boundaries (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is programmed for SDRAM access. Using the temporary configuration, a simple memory test is run that determines the size of the SDRAM banks. When there is more than one SDRAM bank, and the banks are of different size, the largest is mapped first. For equal size, the first bank (CS2#) is mapped first. The first mapping is always for address 0x00000000, with any additional banks following immediately to create contiguous memory starting from 0. Then, the monitor installs itself at the upper end of the SDRAM area and allocates memory for use by malloc() and for the global Board Info data; also, the exception vector code is copied to the low RAM pages, and the final stack is set up. Only after this relocation will you have a "normal" C environment; until that you are restricted in several ways, mostly because you are running from ROM, and because the code will have to be relocated to a new address in RAM. U-Boot Porting Guide: ---------------------- [Based on messages by Jerry Van Baren in the U-Boot-Users mailing list, October 2002] int main(int argc, char *argv[]) {	sighandler_t no_more_time;	signal(SIGALRM, no_more_time);	alarm(PROJECT_DEADLINE - toSec (3 * WEEK));	if (available_money > available_manpower) {	Pay consultant to port U-Boot;	return 0;	}	Download latest U-Boot source;	Subscribe to u-boot mailing list;	if (clueless)	email("Hi, I am new to U-Boot, how do I get started?");	while (learning) {	Read the README file in the top level directory;	Read http://www.denx.de/twiki/bin/view/DULG/Manual;	Read applicable doc/*.README;	Read the source, Luke;	/* find . -name "*.[chS]" | xargs grep -i <keyword> */	}	if (available_money > toLocalCurrency ($2500))	Buy a BDI3000;	else	Add a lot of aggravation and time;	if (a similar board exists) {	/* hopefully... */	cp -a board/<similar> board/<myboard>	cp include/configs/<similar>.h include/configs/<myboard>.h	} else {	Create your own board support subdirectory;	Create your own board include/configs/<myboard>.h file;	}	Edit new board/<myboard> files	Edit new include/configs/<myboard>.h	while (!accepted) {	while (!running) {	do {	Add / modify source code;	} until (compiles);	Debug;	if (clueless)	email("Hi, I am having problems...");	}	Send patch file to the U-Boot email list;	if (reasonable critiques)	Incorporate improvements from email list code review;	else	Defend code as written;	}	return 0; } void no_more_time (int sig) { hire_a_guru(); } Coding Standards: ----------------- All contributions to U-Boot should conform to the Linux kernel coding style; see the file "Documentation/CodingStyle" and the script "scripts/Lindent" in your Linux kernel source directory. Source files originating from a different project (for example the MTD subsystem) are generally exempt from these guidelines and are not reformated to ease subsequent migration to newer versions of those sources. Please note that U-Boot is implemented in C (and to some small parts in Assembler); no C++ is used, so please do not use C++ style comments (//) in your code. Please also stick to the following formatting rules: - remove any trailing white space - use TAB characters for indentation and vertical alignment, not spaces - make sure NOT to use DOS '\r\n' line feeds - do not add more than 2 consecutive empty lines to source files - do not add trailing empty lines to source files Submissions which do not conform to the standards may be returned with a request to reformat the changes. Submitting Patches: ------------------- Since the number of patches for U-Boot is growing, we need to establish some rules. Submissions which do not conform to these rules may be rejected, even when they contain important and valuable stuff. Please see http://www.denx.de/wiki/U-Boot/Patches for details. Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; see http://lists.denx.de/mailman/listinfo/u-boot When you send a patch, please include the following information with it: * For bug fixes: a description of the bug and how your patch fixes this bug. Please try to include a way of demonstrating that the patch actually fixes something. * For new features: a description of the feature and your implementation. * A CHANGELOG entry as plaintext (separate from the patch) * For major contributions, your entry to the CREDITS file * When you add support for a new board, don't forget to add this board to the MAINTAINERS file, too. * If your patch adds new configuration options, don't forget to document these in the README file. * The patch itself. If you are using git (which is *strongly* recommended) you can easily generate the patch using the "git format-patch". If you then use "git send-email" to send it to the U-Boot mailing list, you will avoid most of the common problems with some other mail clients. If you cannot use git, use "diff -purN OLD NEW". If your version of diff does not support these options, then get the latest version of GNU diff. The current directory when running this command shall be the parent directory of the U-Boot source tree (i. e. please make sure that your patch includes sufficient directory information for the affected files). We prefer patches as plain text. MIME attachments are discouraged, and compressed attachments must not be used. * If one logical set of modifications affects or creates several files, all these changes shall be submitted in a SINGLE patch file. * Changesets that contain different, unrelated modifications shall be submitted as SEPARATE patches, one patch per changeset. Notes: * Before sending the patch, run the MAKEALL script on your patched source tree and make sure that no errors or warnings are reported for any of the boards. * Keep your modifications to the necessary minimum: A patch containing several unrelated changes or arbitrary reformats will be returned with a request to re-formatting / split it. * If you modify existing code, make sure that your new code does not add to the memory footprint of the code ;-) Small is beautiful! When adding new features, these should compile conditionally only (using #ifdef), and the resulting code with the new feature disabled must not need more memory than the old code without your modification. * Remember that there is a size limit of 100 kB per message on the u-boot mailing list. Bigger patches will be moderated. If they are reasonable and not too big, they will be acknowledged. But patches bigger than the size limit should be avoided.