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# (C) Copyright 2000 - 2009
# 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.
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)
- 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:
===========
U-Boot uses a 3 level version number containing a version, a
sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
sub-version "34", and patchlevel "4".
The patchlevel is used to indicate certain stages of development
between released versions, i. e. officially released versions of
U-Boot will always have a patchlevel of "0".
- api Machine/arch independent API for external apps
- board Board dependent files
- common Misc architecture independent functions
- 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
- arm720t Files specific to ARM 720 CPUs
- arm920t Files specific to ARM 920 CPUs
- at91rm9200 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
- at32ap Files specific to Atmel AVR32 AP CPUs
- blackfin Files specific to Analog Devices Blackfin CPUs
- i386 Files specific to i386 CPUs
- ixp Files specific to Intel XScale IXP CPUs
- leon2 Files specific to Gaisler LEON2 SPARC CPU
- leon3 Files specific to Gaisler LEON3 SPARC CPU
- 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
- mips Files specific to MIPS 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
- nios Files specific to Altera NIOS CPUs
- nios2 Files specific to Altera Nios-II CPUs
- ppc4xx Files specific to AMCC PowerPC 4xx CPUs
- pxa Files specific to Intel XScale PXA CPUs
- s3c44b0 Files specific to Samsung S3C44B0 CPUs
- sa1100 Files specific to Intel StrongARM SA1100 CPUs
- disk Code for disk drive partition handling
- doc Documentation (don't expect too much)
- examples Example code for standalone applications, etc.
- fs Filesystem code (cramfs, ext2, jffs2, etc.)
- lib_arm Files generic to ARM architecture
- lib_avr32 Files generic to AVR32 architecture
- lib_blackfin Files generic to Blackfin architecture
- lib_generic Files generic to all architectures
- lib_i386 Files generic to i386 architecture
- lib_m68k Files generic to m68k architecture
- lib_microblaze Files generic to microblaze architecture
- lib_mips Files generic to MIPS architecture
- lib_nios Files generic to NIOS architecture
- lib_nios2 Files generic to NIOS2 architecture
- lib_ppc Files generic to PowerPC architecture
- lib_sh Files generic to SH architecture
- lib_sparc Files generic to SPARC architecture
- libfdt Library files to support flattened device trees
- 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
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.
- 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
- 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
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
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.
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
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
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.
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

Matthew McClintock
committed
CONFIG_OF_BOOT_CPU
This define fills in the correct boot CPU in the boot

Matthew McClintock
committed
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.
- 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.
Define this if you want support for Amba PrimeCell PL010 UARTs.
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
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_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
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.
- Interrupt driven serial port input:
CONFIG_SERIAL_SOFTWARE_FIFO
PPC405GP only.
Use an interrupt handler for receiving data on the
serial port. It also enables using hardware handshake
(RTS/CTS) and UART's built-in FIFO. Set the number of
bytes the interrupt driven input buffer should have.
Leave undefined to disable this feature, including
disable the buffer and hardware handshake.
- Console UART Number:
CONFIG_UART1_CONSOLE
If defined internal UART1 (and not UART0) is used
as default U-Boot console.
- 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".
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
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- 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 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_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_EEPROM * EEPROM read/write support
CONFIG_CMD_ELF * bootelf, bootvx
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_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_IRQ * irqinfo
CONFIG_CMD_ITEST Integer/string test of 2 values
CONFIG_CMD_JFFS2 * JFFS2 Support
CONFIG_CMD_KGDB * kgdb
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_SHA1 print sha1 memory digest
(requires CONFIG_CMD_MEMORY)
CONFIG_CMD_SOURCE "source" command Support
CONFIG_CMD_SPI * SPI serial bus support
CONFIG_CMD_USB * USB support
CONFIG_CMD_VFD * VFD support (TRAB)
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!
- Watchdog:
CONFIG_WATCHDOG
If this variable is defined, it enables watchdog
support. There must be support in the platform specific
code for a watchdog. For the 8xx and 8260 CPUs, the
SIU Watchdog feature is enabled in the SYPCR
register.
- 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.
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_DS1307 - use Maxim, Inc. DS1307 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
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
Note that if the GPIO device uses I2C, then the I2C interface
must also be configured. See I2C Support, below.
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.
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)
CONFIG_E1000
Support for Intel 8254x gigabit chips.
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_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_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
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.
- 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
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
- CONFIG_SYS_USB_EXTC_CLK 0x02
CONFIG_SYS_USB_BRG_CLK 0xBLAH
- 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
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
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.
- 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
- 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
video output is selected via environment 'videoout'
(1 = LCD and 2 = CRT). If videoout is undefined, CRT is
assumed.
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
-------------+---------------------------------------------
- "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
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.
NEC NL6448AC33-18. Active, color, single scan.
NEC NL6448BC20-08. 6.5", 640x480.
Active, color, single scan.
CONFIG_NEC_NL6448BC33_54
NEC NL6448BC33-54. 10.4", 640x480.
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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.
- 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
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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
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
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.
- Server IP address:
CONFIG_SERVERIP
Defines a default value for the IP address of a TFTP
server to contact when using the "tftboot" command.
CONFIG_KEEP_SERVERADDR
Keeps the server's MAC address, in the env 'serveraddr'
for passing to bootargs (like Linux's netconsole option)
- 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.
CONFIG_BOOTP_RANDOM_DELAY
- 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

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committed
- 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

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

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committed
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

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committed
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.

Stefan Roese
committed
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.
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.
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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
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
Now, the u-boot i2c code for the mpc8xx (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):
(Optional). Any commands necessary to enable the I2C
controller or configure ports.
eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
(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).
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).
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:
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_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
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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 sends First the Commando to the mux@70 to enable
channel 6, and then the Commando 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_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 only i.MX31 is supported.
Enables FPGA subsystem.
CONFIG_FPGA_<vendor>
Enables support for specific chip vendors.
(ALTERA, XILINX)
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
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
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
- Configuration Management:
CONFIG_IDENT_STRING
If defined, this string will be added to the U-Boot
version information (U_BOOT_VERSION)
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
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}
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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,
PCU_E, 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.
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
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.
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
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_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.
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 lib_<arch>/bootm.c All preparation done, transferring control to OS
-30 lib_ppc/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()
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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

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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
- 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.
[so far only for SMDK2400 and TRAB boards]
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.
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().
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
See also: doc/README.Modem
Configuration Settings:
-----------------------
- CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
- 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
- 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:
- CONFIG_SYS_CONSOLE_INFO_QUIET
- 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
- 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:
- 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,

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committed
this specified memory area will get subtracted from the top
(end) of RAM and won't get "touched" at all by U-Boot. By

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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

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recalculate the memory size from the SDRAM controller setup
will have to get fixed in Linux additionally.

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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:
- 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)
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