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# (C) Copyright 2000 - 2012
# Wolfgang Denk, DENX Software Engineering,
# 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
# 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
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
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.
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
Note: There is no CHANGELOG file in the actual U-Boot source tree;
it can be created dynamically from the Git log using:
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
<>. There is also an archive of previous traffic
on the mailing list - please search the archive before asking FAQ's.
Please see and
Where to get source code:
The U-Boot source code is maintained in the git repository at
git:// ; you can browse it online at;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
Pre-built (and tested) images are available from
Where we come from:
- start from 8xxrom sources
- create PPCBoot project (
- 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 (
- add other CPU families (starting with ARM)
- create U-Boot project (
- current project page: see
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/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
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.
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
* 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
Example: For a TQM823L module, all configuration settings are in
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
--- FIXME --- not tested yet:
- Motherboard Type: (if CONFIG_COGENT is defined)
Define exactly one of
- Motherboard I/O Modules: (if CONFIG_COGENT is defined)
Define one or more of
- 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)
Possible values are:
CONFIG_SYS_8260ADS - original MPC8260ADS
- 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
- 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
- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
See doc/README.MPC866
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
Define this option if you want to enable the
ICache only when Code runs from RAM.
- 85xx CPU Options:
Specifies that the core is a 64-bit PowerPC implementation (implements
the "64" category of the Power ISA). This is necessary for ePAPR
compliance, among other possible reasons.
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.
Defines the string to utilize when trying to match PCIe device
tree nodes for the given platform.
Enables a temporary TLB entry to be used during boot to work
around limitations in e500v1 and e500v2 external debugger
support. This reduces the portions of the boot code where
breakpoints and single stepping do not work. The value of this
symbol should be set to the TLB1 entry to be used for this
Enables a workaround for erratum A004510. If set,
Defines one or two SoC revisions (low 8 bits of SVR)
for which the A004510 workaround should be applied.
The rest of SVR is either not relevant to the decision
of whether the erratum is present (e.g. p2040 versus
p2041) or is implied by the build target, which controls
whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
See Freescale App Note 4493 for more information about
this erratum.
This is the value to write into CCSR offset 0x18600
according to the A004510 workaround.
- Generic CPU options:
Defines the endianess of the CPU. Implementation of those
values is arch specific.
- Intel Monahans options:
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.
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:
Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
pointer. This is needed for the temporary stack before
Cache operation mode for the MIPS CPU.
See also arch/mips/include/asm/mipsregs.h.
Possible values are:
Special option for Lantiq XWAY SoCs for booting from NOR flash.
See also arch/mips/cpu/mips32/start.S.
Enable compilation of tools/xway-swap-bytes needed for Lantiq
XWAY SoCs for booting from NOR flash. The U-Boot image needs to
be swapped if a flash programmer is used.
- ARM options:
Select high exception vectors of the ARM core, e.g., do not
clear the V bit of the c1 register of CP15.
Use this flag to build U-Boot using the Thumb instruction
set for ARM architectures. Thumb instruction set provides
better code density. For ARM architectures that support
Thumb2 this flag will result in Thumb2 code generated by
- Linux Kernel Interface:
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.
New kernel versions are expecting firmware settings to be
passed using flattened device trees (based on open firmware
* 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
Board code has addition modification that it wants to make
to the flat device tree before handing it off to the kernel
This define fills in the correct boot CPU in the boot
param header, the default value is zero if undefined.
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
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_BOOT_ADDR - Address of boot parameters
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
CONFIG_SYS_PL310_BASE - Physical base address of PL310
controller register space
- Serial Ports:
Define this if you want support for Amba PrimeCell PL010 UARTs.
Define this if you want support for Amba PrimeCell PL011 UARTs.
If you have Amba PrimeCell PL011 UARTs, set this variable to
the clock speed of the UARTs.
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
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.
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.
16550 UART set the Transmitter Empty (TEMT) Bit when all output
has finished and the transmitter is totally empty. U-Boot waits
for this bit to be set to initialize the serial console. On some
broken platforms this bit is not set in SPL making U-Boot to
hang while waiting for TEMT. Define this option to avoid it.
- Console Interface:
Depending on board, define exactly one serial port
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(), ...)
Enables console device for a color framebuffer. Needs following
defines (cf. smiLynxEM, i8042)
VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
(default big endian)
VIDEO_HW_RECTFILL graphic chip supports
rectangle fill
(cf. smiLynxEM)
VIDEO_HW_BITBLT graphic chip supports
bit-blit (cf. smiLynxEM)
VIDEO_VISIBLE_COLS visible pixel columns
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.
additional board info beside
the logo
When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
a limited number of ANSI escape sequences (cursor control,
erase functions and limited graphics rendition control).
When CONFIG_CFB_CONSOLE is defined, video console is
default i/o. Serial console can be forced with
environment 'console=serial'.
When CONFIG_SILENT_CONSOLE is defined, all console
messages (by U-Boot and Linux!) can be silenced with
the "silent" environment variable. See
doc/README.silent for more information.
- Console Baudrate:
Select one of the baudrates listed in
- 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.
must be defined, to setup the maximum idle timeout for
the SMC.
- Pre-Console Buffer:
Prior to the console being initialised (i.e. serial UART
initialised etc) all console output is silently discarded.
Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
buffer any console messages prior to the console being
initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
bytes are output before the console is initialised, the
earlier bytes are discarded.
'Sane' compilers will generate smaller code if
CONFIG_PRE_CON_BUF_SZ is a power of 2
- Safe printf() functions
Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
the printf() functions. These are defined in
include/vsprintf.h and include snprintf(), vsnprintf() and
so on. Code size increase is approximately 300-500 bytes.
If this option is not given then these functions will
silently discard their buffer size argument - this means
you are not getting any overflow checking in this case.
- Boot Delay: CONFIG_BOOTDELAY - in seconds
Delay before automatically booting the default image;
set to -1 to disable autoboot.
set to -2 to autoboot with no delay and not check for abort
(even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
See doc/README.autoboot for these options that
work with CONFIG_BOOTDELAY. None are required.
- Autoboot Command:
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.
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
RAM and NFS.
- Pre-Boot Commands:
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:
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)
Select one of the baudrates listed in
- 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_BEDBUG * Include BedBug Debugger
CONFIG_CMD_BSP * Board specific commands
CONFIG_CMD_CACHE * icache, dcache
CONFIG_CMD_CRC32 * crc32
CONFIG_CMD_DATE * support for RTC, date/time...
CONFIG_CMD_DIAG * Diagnostics
CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
CONFIG_CMD_DTT * Digital Therm and Thermostat
CONFIG_CMD_ECHO echo arguments
CONFIG_CMD_EDITENV edit env variable
CONFIG_CMD_EEPROM * EEPROM read/write support
CONFIG_CMD_ELF * bootelf, bootvx
CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
CONFIG_CMD_ENV_FLAGS * display details about env flags
CONFIG_CMD_EXPORTENV * export the environment
CONFIG_CMD_EXT2 * ext2 command support
CONFIG_CMD_EXT4 * ext4 command support
CONFIG_CMD_FDC * Floppy Disk Support
CONFIG_CMD_FAT * FAT command support
CONFIG_CMD_FDOS * Dos diskette Support
CONFIG_CMD_FLASH flinfo, erase, protect
CONFIG_CMD_FPGA FPGA device initialization support
CONFIG_CMD_GETTIME * Get time since boot
CONFIG_CMD_GO * the 'go' command (exec code)
CONFIG_CMD_GREPENV * search environment
CONFIG_CMD_HASH * calculate hash / digest
CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
CONFIG_CMD_I2C * I2C serial bus support
CONFIG_CMD_IDE * IDE harddisk support
CONFIG_CMD_IMLS List all found images
CONFIG_CMD_IMMAP * IMMR dump support
CONFIG_CMD_IMPORTENV * import an environment
CONFIG_CMD_INI * import data from an ini file into the env
CONFIG_CMD_IRQ * irqinfo
CONFIG_CMD_ITEST Integer/string test of 2 values
CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
CONFIG_CMD_MD5SUM print md5 message digest
CONFIG_CMD_MEMINFO * Display detailed memory information
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_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_READ * Read raw data from partition
CONFIG_CMD_REGINFO * Register dump
CONFIG_CMD_RUN run command in env variable
CONFIG_CMD_SAVES * save S record dump
CONFIG_CMD_SDRAM * print SDRAM configuration information
(requires CONFIG_CMD_I2C)
CONFIG_CMD_SETGETDCR Support for DCR Register access
(4xx only)
CONFIG_CMD_SF * Read/write/erase SPI NOR flash
CONFIG_CMD_SHA1SUM print sha1 memory digest
CONFIG_CMD_SOURCE "source" command Support
CONFIG_CMD_SPI * SPI serial bus support
CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
CONFIG_CMD_TFTPPUT * TFTP put command (upload)
CONFIG_CMD_TIME * run command and report execution time (ARM specific)
CONFIG_CMD_TIMER * access to the system tick timer
CONFIG_CMD_CDP * Cisco Discover Protocol support
CONFIG_CMD_MFSL * Microblaze FSL support
EXAMPLE: If you want all functions except of network
support you can write:
#include "config_cmd_all.h"
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:
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:
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.
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
- 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.
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:
If this variable is defined, an environment variable
named "ver" is created by U-Boot showing the U-Boot
version as printed by the "version" command.
Any change to this variable will be reverted at the
next reset.
- Real-Time Clock:
When CONFIG_CMD_DATE is selected, the type of the RTC
has to be selected, too. Define exactly one of the
following options:
CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
CONFIG_RTC_MC146818 - use MC146818 RTC
CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
CONFIG_RTC_DS164x - use Dallas DS164x RTC
CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
CONFIG_SYS_RV3029_TCR - enable trickle charger on
RV3029 RTC.
Note that if the RTC uses I2C, then the I2C interface
must also be configured. See I2C Support, below.
- GPIO Support:
CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
CONFIG_PCA953X_INFO - enable pca953x info command
The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
chip-ngpio pairs that tell the PCA953X driver the number of
pins supported by a particular chip.
Note that if the GPIO device uses I2C, then the I2C interface
must also be configured. See I2C Support, below.
- Timestamp Support:
When CONFIG_TIMESTAMP is selected, the timestamp
(date and time) of an image is printed by image
commands like bootm or iminfo. This option is
automatically enabled when you select CONFIG_CMD_DATE .
- Partition Labels (disklabels) Supported:
Zero or more of the following:
CONFIG_MAC_PARTITION Apple's MacOS partition table.
CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
Intel architecture, USB sticks, etc.
CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
bootloader. Note 2TB partition limit; see
CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
CONFIG_CMD_SCSI) you must configure support for at
least one non-MTD partition type as well.
- IDE Reset method:
CONFIG_IDE_RESET_ROUTINE - this is defined in several
board configurations files but used nowhere!
CONFIG_IDE_RESET - is this is defined, IDE Reset will
be performed by calling the function
ide_set_reset(int reset)
which has to be defined in a board specific file
- ATAPI Support:
Set this to enable ATAPI support.
- LBA48 Support
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.
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] can be adjusted to define the
maximum numbers of LUNs, SCSI ID's and target
CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
The environment variable 'scsidevs' is set to the number of
SCSI devices found during the last scan.
- NETWORK Support (PCI):
Support for Intel 8254x/8257x gigabit chips.
Utility code for direct access to the SPI bus on Intel 8257x.
This does not do anything useful unless you set at least one
Allow generic access to the SPI bus on the Intel 8257x, for
example with the "sspi" command.
Management command for E1000 devices. When used on devices
with SPI support you can reprogram the EEPROM from U-Boot.
default MAC for empty EEPROM after production.
Support for Intel 82557/82559/82559ER chips.
write routine for first time initialisation.
Support for Digital 2114x chips.
Optional CONFIG_TULIP_SELECT_MEDIA for board specific
modem chip initialisation (KS8761/QS6611).
Support for National dp83815 chips.
Support for National dp8382[01] gigabit chips.
- NETWORK Support (other):
Support for AT91RM9200 EMAC.
Define this to use reduced MII inteface
If this defined, the driver is quiet.
The driver doen't show link status messages.
Support for the Calxeda XGMAC device
Support for SMSC's LAN91C96 chips.
Define this to hold the physical address
of the LAN91C96's I/O space
Define this to enable 32 bit addressing
Support for SMSC's LAN91C111 chip
Define this to hold the physical address
of the device (I/O space)
Define this if data bus is 32 bits
Define this to use i/o functions instead of macros
(some hardware wont work with macros)
Support for davinci emac
Define this if you have more then 3 PHYs.
Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
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.
Support for SMSC's LAN911x and LAN921x chips
Define this to hold the physical address
of the device (I/O space)
Define this if data bus is 32 bits
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.
Support for Renesas on-chip Ethernet controller
Define the number of ports to be used
Define the ETH PHY's address
If this option is set, the driver enables cache flush.
- TPM Support:
Support for generic parallel port TPM devices. Only one device
per system is supported at this time.
Base address where the generic TPM device is mapped
to. Contemporary x86 systems usually map it at
- 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.
Supported are USB Keyboards and USB Floppy drives
MPC5200 USB requires additional defines:
for 528 MHz Clock: 0x0001bbbb
for USB on PSC3
for differential drivers: 0x00001000
for single ended drivers: 0x00005000
for differential drivers on PSC3: 0x00000100
for single ended drivers on PSC3: 0x00004100
May be defined to allow interrupt polling
instead of using asynchronous interrupts
CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
txfilltuning field in the EHCI controller on reset.
- USB Device:
Define the below if you wish to use the USB console.
Once firmware is rebuilt from a serial console issue the
command "setenv stdin usbtty; setenv stdout usbtty" and
attach your USB cable. The Unix command "dmesg" should print
it has found a new device. The environment variable usbtty
can be set to gserial or cdc_acm to enable your device to
appear to a USB host as a Linux gserial device or a
Common Device Class Abstract Control Model serial device.
If you select usbtty = gserial you should be able to enumerate
a Linux host by
# modprobe usbserial vendor=0xVendorID product=0xProductID
else if using cdc_acm, simply setting the environment
variable usbtty to be cdc_acm should suffice. The following
might be defined in YourBoardName.h
Define this to build a UDC device
Define this to have a tty type of device available to
talk to the UDC device
Define this to enable the high speed support for usb
device and usbtty. If this feature is enabled, a routine
int is_usbd_high_speed(void)
also needs to be defined by the driver to dynamically poll
whether the enumeration has succeded at high speed or full
Define this if you want stdin, stdout &/or stderr to
be set to usbtty.
Derive USB clock from external clock "blah"
Derive USB clock from brgclk
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
should pretend to be a Linux device to it's target host.
Define this string as the name of your company for
Define this string as the name of your product
- CONFIG_USBD_PRODUCT_NAME "acme usb device"
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.
Define this as the unique Product ID
for your device
- ULPI Layer Support:
The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
the generic ULPI layer. The generic layer accesses the ULPI PHY
via the platform viewport, so you need both the genric layer and
the viewport enabled. Currently only Chipidea/ARC based
viewport is supported.
To enable the ULPI layer support, define CONFIG_USB_ULPI and
CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
If your ULPI phy needs a different reference clock than the
standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
the appropriate value in Hz.
- MMC Support:
The MMC controller on the Intel PXA is supported. To
enable this define CONFIG_MMC. The MMC can be
accessed from the boot prompt by mapping the device
to physical memory similar to flash. Command line is
enabled with CONFIG_CMD_MMC. The MMC driver also works with
the FAT fs. This is enabled with CONFIG_CMD_FAT.
Support for Renesas on-chip MMCIF controller
Define the base address of MMCIF registers
Define the clock frequency for MMCIF
- Journaling Flash filesystem support:
Define these for a default partition on a NAND device
Define these for a default partition on a NOR device
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
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:
Define this to enable support for saving memory data as a
file in FAT formatted partition.
This will also enable the command "fatwrite" enabling the
user to write files to FAT.
CBFS (Coreboot Filesystem) support
Define this to enable support for reading from a Coreboot
filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
and cbfsload.
- Keyboard Support:
Define this to enable standard (PC-Style) keyboard
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:
Define this to enable video support (for output to
Enable Chips & Technologies 69000 Video chip
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
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)
Enable Epson SED13806 driver. This driver supports 8bpp
and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
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:
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 for a
description of this variable.
Enable the VGA video / BIOS for x86. The alternative if you
are using coreboot is to use the coreboot frame buffer
- Keyboard Support:
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.
Define this to enable LCD support (for output to LCD
display); also select one of the supported displays
by defining one of these:
HITACHI TX09D70VM1CCA, 3.5", 240x320.
NEC NL6448AC33-18. Active, color, single scan.
NEC NL6448BC20-08. 6.5", 640x480.
Active, color, single scan.
NEC NL6448BC33-54. 10.4", 640x480.
Active, color, single scan.
Sharp 320x240. Active, color, single scan.
It isn't 16x9, and I am not sure what it is.
Sharp LQ64D341 display, 640x480.
Active, color, single scan.
HLD1045 display, 640x480.
Active, color, single scan.
Optrex CBL50840-2 NF-FW 99 22 M5
Hitachi LMG6912RPFC-00T
Hitachi SP14Q002
320x240. Black & white.
Normally display is black on white background; define
CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
Normally the LCD is page-aligned (tyically 4KB). If this is
defined then the LCD will be aligned to this value instead.
For ARM it is sometimes useful to use MMU_SECTION_SIZE
here, since it is cheaper to change data cache settings on
a per-section basis.
When the console need to be scrolled, this is the number of
lines to scroll by. It defaults to 1. Increasing this makes
the console jump but can help speed up operation when scrolling
is slow.
Support drawing of RLE8-compressed bitmaps on the LCD.
Enables an 'i2c edid' command which can read EDID
information over I2C from an attached LCD display.
- Splash Screen Support: CONFIG_SPLASH_SCREEN
If this option is set, the environment is checked for
a variable "splashimage". If found, the usual display
of logo, copyright and system information on the LCD
is suppressed and the BMP image at the address
specified in "splashimage" is loaded instead. The
console is redirected to the "nulldev", too. This
allows for a "silent" boot where a splash screen is
loaded very quickly after power-on.
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.
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.
- Do compresssing for memory range:
If this option is set, it would use zlib deflate method
to compress the specified memory at its best effort.
- Compression support:
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.
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
(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:
The address of PHY on MII bus.
The clock frequency of the MII bus
If this option is set, support for speed/duplex
detection of gigabit PHY is included.
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)
Some PHY like Intel LXT971A need extra delay after
command issued before MII status register can be read
- Ethernet address:
Define a default value for Ethernet address to use
for the respective Ethernet interface, in case this
is not determined automatically.
- IP address:
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:
Defines a default value for the IP address of a TFTP
server to contact when using the "tftboot" command.
(Environment variable "serverip")
Keeps the server's MAC address, in the env 'serveraddr'
for passing to bootargs (like Linux's netconsole option)
- Gateway IP address:
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:
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:
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:
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_SERVERIP - TFTP server will be the serverip
environment variable, not the BOOTP server.
CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
after the configured retry count, the call will fail
instead of starting over. This can be used to fail over
to Link-local IP address configuration if the DHCP server
is not available.
CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
serverip from a DHCP server, it is possible that more
than one DNS serverip is offered to the client.
If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
serverip will be stored in the additional environment
variable "dnsip2". The first DNS serverip is always
stored in the variable "dnsip", when CONFIG_BOOTP_DNS
is defined.
CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
to do a dynamic update of a DNS server. To do this, they
need the hostname of the DHCP requester.
If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
of the "hostname" environment variable is passed as
option 12 to the DHCP server.
A 32bit value in microseconds for a delay between
receiving a "DHCP Offer" and sending the "DHCP Request".
This fixes a problem with certain DHCP servers that don't
respond 100% of the time to a "DHCP request". E.g. On an
AT91RM9200 processor running at 180MHz, this delay needed
to be *at least* 15,000 usec before a Windows Server 2003
DHCP server would reply 100% of the time. I recommend at
least 50,000 usec to be safe. The alternative is to hope
that one of the retries will be successful but note that
the DHCP timeout and retry process takes a longer than
this delay.
- Link-local IP address negotiation:
Negotiate with other link-local clients on the local network
for an address that doesn't require explicit configuration.
This is especially useful if a DHCP server cannot be guaranteed
to exist in all environments that the device must operate.
See doc/ for more information.
- CDP Options:
The device id used in CDP trigger frames.
A two character string which is prefixed to the MAC address
of the device.
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.
A 32bit integer which indicates the device capabilities;
0x00000010 for a normal host which does not forwards.
An ascii string containing the version of the software.
An ascii string containing the name of the platform.
A 32bit integer sent on the trigger.
A 16bit integer containing the power consumption of the
device in .1 of milliwatts.
A byte containing the id of the VLAN.
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.
Defining CONFIG_CAN_DRIVER enables CAN driver support
on those systems that support this (optional)
feature, like the TQM8xxL modules.
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
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.
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)
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)
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)
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
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
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
#define I2C_DELAY udelay(2)
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.
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.
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).
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)
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.
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
#define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
will skip addresses 0x50 and 0x68 on a board with one I2C 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
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.
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.
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.
If defined, specifies the I2C address of the DTT device.
If not defined, then U-Boot uses predefined value for
specified DTT device.
Define this option if you want to use Freescale's I2C driver in
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
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.
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.
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)
Enables the driver for SPI controller on SuperH. Currently
only SH7757 is supported.
Enables extended (16-bit) SPI EEPROM addressing.
(symmetrical to CONFIG_I2C_X)
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.
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.
Enables the driver for the SPI controllers on i.MX and MXC
SoCs. Currently i.MX31/35/51 are supported.
Enables FPGA subsystem.
Enables support for specific chip vendors.
Enables support for FPGA family.
Specify the number of FPGA devices to support.
Enable printing of hash marks during FPGA configuration.
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.
If defined, a function that provides delays in the FPGA
configuration driver.
Allow Control-C to interrupt FPGA configuration
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).
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
Maximum time to wait for BUSY to deassert during
Virtex II FPGA configuration. The default is 5 ms.
Time to wait after FPGA configuration. The default is
200 ms.
- Configuration Management:
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
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
The same can be accomplished in a more flexible way
for any variable by configuring the type of access
to allow for those variables in the ".flags" variable
- Protected RAM:
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}
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
IVMS8, IVML24, SPD8xx, TQM8xxL,
- Access to physical memory region (> 4GB)
Some basic support is provided for operations on memory not
normally accessible to U-Boot - e.g. some architectures
support access to more than 4GB of memory on 32-bit
machines using physical address extension or similar.
Define CONFIG_PHYSMEM to access this basic support, which
currently only supports clearing the memory.
- Error Recovery:
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.
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.
Timeout waiting for an ARP reply in milliseconds.
Timeout in milliseconds used in NFS protocol.
If you encounter "ERROR: Cannot umount" in nfs command,
try longer timeout such as
- Command Interpreter:
Enable auto completion of commands using TAB.
Note that this feature has NOT been implemented yet
for the "hush" shell.
Define this variable to enable the "hush" shell (from
Busybox) as command line interpreter, thus enabling
powerful command line syntax like conditionals or `&&' and '||'
constructs ("shell scripts").
If undefined, you get the old, much simpler behaviour
with a somewhat smaller memory footprint.
This defines the secondary prompt string, which is
printed when the command interpreter needs more input
to complete a command. Usually "> ".
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
- Commandline Editing and History:
Enable editing and History functions for interactive
commandline input operations
- Default Environment:
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:
"myvar1=value1\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.
Define this in order to add variables describing the
U-Boot build configuration to the default environment.
These will be named arch, cpu, board, vendor, and soc.
Enabling this option will cause the following to be defined:
Define this in order to add variables describing certain
run-time determined information about the hardware to the
environment. These will be named board_name, board_rev.
Normally the environment is loaded when the board is
intialised so that it is available to U-Boot. This inhibits
that so that the environment is not available until
explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
this is instead controlled by the value of
- DataFlash Support:
Defining this option enables DataFlash features and
allows to read/write in Dataflash via the standard
commands cp, md...
- Serial Flash support
Defining this option enables SPI flash commands
'sf probe/read/write/erase/update'.
Usage requires an initial 'probe' to define the serial
flash parameters, followed by read/write/erase/update
The following defaults may be provided by the platform
to handle the common case when only a single serial
flash is present on the system.
CONFIG_SF_DEFAULT_MODE (see include/spi.h)
Define this option to include a destructive SPI flash
test ('sf test').
- SystemACE Support:
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
#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:
If this is defined, the environment variable tftpsrcp
is used to supply the TFTP UDP source port value.
If tftpsrcp isn't defined, the normal pseudo-random port
number generator is used.
Also, the environment variable tftpdstp is used to supply
the TFTP UDP destination port value. If tftpdstp isn't
defined, the normal port 69 is used.
The purpose for tftpsrcp is to allow a TFTP server to
blindly start the TFTP transfer using the pre-configured
target IP address and UDP port. This has the effect of
"punching through" the (Windows XP) firewall, allowing
the remainder of the TFTP transfer to proceed normally.
A better solution is to properly configure the firewall,
but sometimes that is not allowed.
- Hashing support:
This enables a generic 'hash' command which can produce
hashes / digests from a few algorithms (e.g. SHA1, SHA256).
Enable the hash verify command (hash -v). This adds to code
size a little.
CONFIG_SHA1 - support SHA1 hashing
CONFIG_SHA256 - support SHA256 hashing
Note: There is also a sha1sum command, which should perhaps
be deprecated in favour of 'hash sha1'.
- Show boot progress:
Defining this option allows to add some board-
specific code (calling a user-provided function
"show_boot_progress(int)") that enables you to show
the system's boot progress on some display (for
example, some LED's) on your board. At the moment,
the following checkpoints are implemented:
- Detailed boot stage timing
Define this option to get detailed timing of each stage
of the boot process.
This is the number of available user bootstage records.
Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
a new ID will be allocated from this stash. If you exceed
the limit, recording will stop.
Define this to print a report before boot, similar to this:
Timer summary in microseconds:
Mark Elapsed Stage
0 0 reset
3,575,678 3,575,678 board_init_f start
3,575,695 17 arch_cpu_init A9
3,575,777 82 arch_cpu_init done
3,659,598 83,821 board_init_r start
3,910,375 250,777 main_loop
29,916,167 26,005,792 bootm_start
30,361,327 445,160 start_kernel
Add a 'bootstage' command which supports printing a report
and un/stashing of bootstage data.
Stash the bootstage information in the FDT. A root 'bootstage'
node is created with each bootstage id as a child. Each child
has a 'name' property and either 'mark' containing the
mark time in microsecond, or 'accum' containing the
accumulated time for that bootstage id in microseconds.
For example:
bootstage {
154 {
name = "board_init_f";
mark = <3575678>;
170 {
name = "lcd";
accum = <33482>;
Code in the Linux kernel can find this in /proc/devicetree.
Legacy uImage format:
Arg Where When
1 common/cmd_bootm.c before attempting to boot an image
-1 common/cmd_bootm.c Image header has bad magic number
2 common/cmd_bootm.c Image header has correct magic number
-2 common/cmd_bootm.c Image header has bad checksum
3 common/cmd_bootm.c Image header has correct checksum
-3 common/cmd_bootm.c Image data has bad checksum
4 common/cmd_bootm.c Image data has correct checksum
-4 common/cmd_bootm.c Image is for unsupported architecture
5 common/cmd_bootm.c Architecture check OK
-5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
6 common/cmd_bootm.c Image Type check OK
-6 common/cmd_bootm.c gunzip uncompression error
-7 common/cmd_bootm.c Unimplemented compression type
7 common/cmd_bootm.c Uncompression OK
8 common/cmd_bootm.c No uncompress/copy overwrite error
-9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
9 common/image.c Start initial ramdisk verification
-10 common/image.c Ramdisk header has bad magic number
-11 common/image.c Ramdisk header has bad checksum
10 common/image.c Ramdisk header is OK
-12 common/image.c Ramdisk data has bad checksum
11 common/image.c Ramdisk data has correct checksum
12 common/image.c Ramdisk verification complete, start loading
-13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
13 common/image.c Start multifile image verification
14 common/image.c No initial ramdisk, no multifile, continue.
15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
-30 arch/powerpc/lib/board.c Fatal error, hang the system
-31 post/post.c POST test failed, detected by post_output_backlog()
-32 post/post.c POST test failed, detected by post_run_single()
34 common/cmd_doc.c before loading a Image from a DOC device
-35 common/cmd_doc.c Bad usage of "doc" command
35 common/cmd_doc.c correct usage of "doc" command
-36 common/cmd_doc.c No boot device
36 common/cmd_doc.c correct boot device
-37 common/cmd_doc.c Unknown Chip ID on boot device
37 common/cmd_doc.c correct chip ID found, device available
-38 common/cmd_doc.c Read Error on boot device
38 common/cmd_doc.c reading Image header from DOC device OK
-39 common/cmd_doc.c Image header has bad magic number
39 common/cmd_doc.c Image header has correct magic number
-40 common/cmd_doc.c Error reading Image from DOC device
40 common/cmd_doc.c Image header has correct magic number
41 common/cmd_ide.c before loading a Image from a IDE device
-42 common/cmd_ide.c Bad usage of "ide" command
42 common/cmd_ide.c correct usage of "ide" command
-43 common/cmd_ide.c No boot device
43 common/cmd_ide.c boot device found
-44 common/cmd_ide.c Device not available
44 common/cmd_ide.c Device available
-45 common/cmd_ide.c wrong partition selected
45 common/cmd_ide.c partition selected
-46 common/cmd_ide.c Unknown partition table
46 common/cmd_ide.c valid partition table found
-47 common/cmd_ide.c Invalid partition type
47 common/cmd_ide.c correct partition type
-48 common/cmd_ide.c Error reading Image Header on boot device
48 common/cmd_ide.c reading Image Header from IDE device OK
-49 common/cmd_ide.c Image header has bad magic number
49 common/cmd_ide.c Image header has correct magic number
-50 common/cmd_ide.c Image header has bad checksum
50 common/cmd_ide.c Image header has correct checksum
-51 common/cmd_ide.c Error reading Image from IDE device
51 common/cmd_ide.c reading Image from IDE device OK
52 common/cmd_nand.c before loading a Image from a NAND device
-53 common/cmd_nand.c Bad usage of "nand" command
53 common/cmd_nand.c correct usage of "nand" command
-54 common/cmd_nand.c No boot device
54 common/cmd_nand.c boot device found
-55 common/cmd_nand.c Unknown Chip ID on boot device
55 common/cmd_nand.c correct chip ID found, device available
-56 common/cmd_nand.c Error reading Image Header on boot device
56 common/cmd_nand.c reading Image Header from NAND device OK
-57 common/cmd_nand.c Image header has bad magic number
57 common/cmd_nand.c Image header has correct magic number
-58 common/cmd_nand.c Error reading Image from NAND device
58 common/cmd_nand.c reading Image from NAND device OK
-60 common/env_common.c Environment has a bad CRC, using default
64 net/eth.c starting with Ethernet configuration.
-64 net/eth.c no Ethernet found.
65 net/eth.c Ethernet found.
-80 common/cmd_net.c usage wrong
80 common/cmd_net.c before calling NetLoop()
-81 common/cmd_net.c some error in NetLoop() occurred
81 common/cmd_net.c NetLoop() back without error
-82 common/cmd_net.c size == 0 (File with size 0 loaded)
82 common/cmd_net.c trying automatic boot
83 common/cmd_net.c running "source" command
-83 common/cmd_net.c some error in automatic boot or "source" command
84 common/cmd_net.c end without errors
FIT uImage format:
Arg Where When
100 common/cmd_bootm.c Kernel FIT Image has correct format
-100 common/cmd_bootm.c Kernel FIT Image has incorrect format
101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
-101 common/cmd_bootm.c Can't get configuration for kernel subimage
102 common/cmd_bootm.c Kernel unit name specified
-103 common/cmd_bootm.c Can't get kernel subimage node offset
103 common/cmd_bootm.c Found configuration node
104 common/cmd_bootm.c Got kernel subimage node offset
-104 common/cmd_bootm.c Kernel subimage hash verification failed
105 common/cmd_bootm.c Kernel subimage hash verification OK
-105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
106 common/cmd_bootm.c Architecture check OK
-106 common/cmd_bootm.c Kernel subimage has wrong type
107 common/cmd_bootm.c Kernel subimage type OK
-107 common/cmd_bootm.c Can't get kernel subimage data/size
108 common/cmd_bootm.c Got kernel subimage data/size
-108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
-109 common/cmd_bootm.c Can't get kernel subimage type
-110 common/cmd_bootm.c Can't get kernel subimage comp
-111 common/cmd_bootm.c Can't get kernel subimage os
-112 common/cmd_bootm.c Can't get kernel subimage load address
-113 common/cmd_bootm.c Image uncompress/copy overwrite error
120 common/image.c Start initial ramdisk verification
-120 common/image.c Ramdisk FIT image has incorrect format
121 common/image.c Ramdisk FIT image has correct format
122 common/image.c No ramdisk subimage unit name, using configuration
-122 common/image.c Can't get configuration for ramdisk subimage
123 common/image.c Ramdisk unit name specified
-124 common/image.c Can't get ramdisk subimage node offset
125 common/image.c Got ramdisk subimage node offset
-125 common/image.c Ramdisk subimage hash verification failed
126 common/image.c Ramdisk subimage hash verification OK
-126 common/image.c Ramdisk subimage for unsupported architecture
127 common/image.c Architecture check OK
-127 common/image.c Can't get ramdisk subimage data/size
128 common/image.c Got ramdisk subimage data/size
129 common/image.c Can't get ramdisk load address
-129 common/image.c Got ramdisk load address
-130 common/cmd_doc.c Incorrect FIT image format
131 common/cmd_doc.c FIT image format OK
-140 common/cmd_ide.c Incorrect FIT image format
141 common/cmd_ide.c FIT image format OK
-150 common/cmd_nand.c Incorrect FIT image format
151 common/cmd_nand.c FIT image format OK
- FIT image support:
Enable support for the FIT uImage format.
When no configuration is explicitly selected, default to the
one whose fdt's compatibility field best matches that of
U-Boot itself. A match is considered "best" if it matches the
most specific compatibility entry of U-Boot's fdt's root node.
The order of entries in the configuration's fdt is ignored.
- Standalone program support:
This option defines a board specific value for the
address where standalone program gets loaded, thus
overwriting the architecture dependent default
- Frame Buffer Address:
Define CONFIG_FB_ADDR if you want to use specific
address for frame buffer. This is typically the case
when using a graphics controller has separate video
memory. U-Boot will then place the frame buffer at
the given address instead of dynamically reserving it
in system RAM by calling lcd_setmem(), which grabs
the memory for the frame buffer depending on the
configured panel size.
Please see board_init_f function.
- Automatic software updates via TFTP server
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)
Adds the MTD device infrastructure from the Linux kernel.
Needed for mtdparts command support.
Adds the MTD partitioning infrastructure from the Linux
kernel. Needed for UBI support.
- SPL framework
Enable building of SPL globally.
LDSCRIPT for linking the SPL binary.
Maximum binary size (text, data and rodata) of the SPL binary.
TEXT_BASE for linking the SPL binary.
Address to relocate to. If unspecified, this is equal to
CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
Link address for the BSS within the SPL binary.
Maximum binary size of the BSS section of the SPL binary.
Adress of the start of the stack SPL will use
Adress of the start of the stack SPL will use after
relocation. If unspecified, this is equal to
Starting address of the malloc pool used in SPL.
The size of the malloc pool used in SPL.
Enable the SPL framework under common/. This framework
supports MMC, NAND and YMODEM loading of U-Boot and NAND
NAND loading of the Linux Kernel.
For ARM, enable an optional function to print more information
about the running system.
Arch init code should be built for a very small image
Support for common/libcommon.o in SPL binary
Support for disk/libdisk.o in SPL binary
Support for drivers/i2c/libi2c.o in SPL binary
Support for drivers/gpio/libgpio.o in SPL binary
Support for drivers/mmc/libmmc.o in SPL binary
Address, size and partition on the MMC to load U-Boot from
when the MMC is being used in raw mode.
Support for fs/fat/libfat.o in SPL binary
Filename to read to load U-Boot when reading from FAT
Include nand_base.c in the SPL. Requires
SPL uses normal NAND drivers, not minimal drivers.
Include standard software ECC in the SPL
Support for NAND boot using simple NAND drivers that
expose the cmd_ctrl() interface.
Defines the size and behavior of the NAND that SPL uses
to read U-Boot
Location in NAND to read U-Boot from
Location in memory to load U-Boot to
Size of image to load
Entry point in loaded image to jump to
Define this if you need to first read the OOB and then the
data. This is used for example on davinci plattforms.
Support for an OMAP3-specific set of functions to return the
ID and MFR of the first attached NAND chip, if present.
Support for drivers/serial/libserial.o in SPL binary
Support for drivers/mtd/spi/libspi_flash.o in SPL binary
Support for drivers/spi/libspi.o in SPL binary
Support for running image already present in ram, in SPL binary
Support for lib/libgeneric.o in SPL binary
Final target image containing SPL and payload. Some SPLs
use an arch-specific makefile fragment instead, for
example if more than one image needs to be produced.
Modem Support:
[so far only for SMDK2400 boards]
- Modem support enable:
- RTS/CTS Flow control enable:
- Modem debug support:
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
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
List of legal baudrate settings for this board.
Suppress display of console information at boot.
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.
Enable the call to overwrite_console().
Enable overwrite of previous console environment settings.
Begin and End addresses of the area used by the
simple memory test.
Enable an alternate, more extensive memory test.
Scratch address used by the alternate memory test
You only need to set this if address zero isn't writeable
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
Enable temporary baudrate change while serial download
Physical start address of SDRAM. _Must_ be 0 here.
Physical start address of Motherboard I/O (if using a
Cogent motherboard)
Physical start address of Flash memory.
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.
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.
Size of DRAM reserved for malloc() use.
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.
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
then the value in "bootm_size" will be used instead.
Enable initrd_high functionality. If defined then the
initrd_high feature is enabled and the bootm ramdisk subcommand
is enabled.
Enables allocating and saving kernel cmdline in space between
"bootm_low" and "bootm_low" + BOOTMAPSZ.
Enables allocating and saving a kernel copy of the bd_info in
space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
Max number of Flash memory banks
Max number of sectors on a Flash chip
Timeout for Flash erase operations (in ms)
Timeout for Flash write operations (in ms)
Timeout for Flash set sector lock bit operation (in ms)
Timeout for Flash clear lock bits operation (in ms)
If defined, hardware flash sectors protection is used
instead of U-Boot software protection.
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.
Define if the flash driver uses extra elements in the
common flash structure for storing flash geometry.
This option also enables the building of the cfi_flash driver
in the drivers directory
This option enables the building of the cfi_mtd driver
in the drivers directory. The driver exports CFI flash
to the MTD layer.
Use buffered writes to flash.
s29ws-n MirrorBit flash has non-standard addresses for buffered
write commands.
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.
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.
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.
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.
Enable validation of the values given to enviroment variables when
calling env set. Variables can be restricted to only decimal,
hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
the variables can also be restricted to IP address or MAC address.
The format of the list is:
type_attribute = [s|d|x|b|i|m]
access_atribute = [a|r|o|c]
attributes = type_attribute[access_atribute]
entry = variable_name[:attributes]
list = entry[,list]
The type attributes are:
s - String (default)
d - Decimal
x - Hexadecimal
b - Boolean ([1yYtT|0nNfF])
i - IP address
m - MAC address
The access attributes are:
a - Any (default)
r - Read-only
o - Write-once
c - Change-default
Define this to a list (string) to define the ".flags"
envirnoment variable in the default or embedded environment.
Define this to a list (string) to define validation that
should be done if an entry is not found in the ".flags"
environment variable. To override a setting in the static
list, simply add an entry for the same variable name to the
".flags" variable.
If defined, don't allow the -f switch to env set override variable
access flags.
The following definitions that deal with the placement and management
of environment data (variable area); in general, we support the
following configurations:
Builds up envcrc with the target environment so that external utils
may easily extract it and embed it in final U-Boot images.
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.
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.
This is just another way to specify the start address of
the flash sector containing the environment (instead of
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.
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.
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>/*
Define this if you have some non-volatile memory device
(NVRAM, battery buffered SRAM) which you want to use for the
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
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.
Use this if you have an EEPROM or similar serial access
device and a driver for it.
These two #defines specify the offset and size of the
environment area within the total memory of your EEPROM.
If defined, specified the chip address of the EEPROM device.
The default address is zero.
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.
If defined, the number of milliseconds to delay between
page writes. The default is zero milliseconds.
The length in bytes of the EEPROM memory array address. Note
that this is NOT the chip address length!
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.
The size in bytes of the EEPROM device.
define this, if you have I2C and SPI activated, and your
EEPROM, which holds the environment, is on the I2C 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.
Define this if you have a DataFlash memory device which you
want to use for the environment.
These three #defines specify the offset and size of the
environment area within the total memory of your DataFlash placed
at the specified address.
Define this if you have a remote memory space which you
want to use for the local device's environment.
These two #defines specify the address and size of the
environment area within the remote memory space. The
local device can get the environment from remote memory
space by SRIO or PCIE links.
BE CAREFUL! For some special cases, the local device can not use
"saveenv" command. For example, the local device will get the
environment stored in a remote NOR flash by SRIO or PCIE link,
but it can not erase, write this NOR flash by SRIO or PCIE interface.
Define this if you have a NAND device which you want to use
for the environment.
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.
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.
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
Defines address in RAM to which the nand_spl code should copy the
environment. If redundant environment is used, it will be copied to
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.
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.
MII address of the PHY to check for the Ethernet link state.
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.
Display information about the board that U-Boot is running on
when U-Boot starts up. The board function checkboard() is called
to do this.
Similar to the previous option, but display this information
later, once stdio is running and output goes to the LCD, if
Low Level (hardware related) configuration options:
Cache Line Size of the CPU.
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.
Default (power-on reset) physical address of CCSR on Freescale
PowerPC SOCs.
Virtual address of CCSR. On a 32-bit build, this is typically
CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
for cross-platform code that uses that macro instead.
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:
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").
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").
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:
the default drive number (default value 0)
defines the spacing between FDC chipset registers
(default value 1)
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)
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
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]
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
U-Boot uses the following memory types:
- MPC8xx and MPC8260: IMMR (internal memory of the CPU)
- MPC824X: data cache
- PPC4xx: data cache
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 +
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)
SDRAM timing
periodic timer for refresh
- CONFIG_SYS_DER: Debug Event Register (37-47)
Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
Machine Mode Register and Memory Periodic Timer
Prescaler definitions (SDRAM timing)
enable I2C microcode relocation patch (MPC8xx);
define relocation offset in DPRAM [DSP2]
enable SMC microcode relocation patch (MPC8xx);
define relocation offset in DPRAM [SMC1]
enable SPI microcode relocation patch (MPC8xx);
define relocation offset in DPRAM [SCC4]
Use OSCM clock mode on MBX8xx board. Be careful,
wrong setting might damage your board. Read
doc/README.MBX before setting this variable!
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.
Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
Disable PCI-Express on systems where it is supported but not
Only scan through and get the devices on the busses.
Don't do any setup work, presumably because someone or
something has already done it, and we don't need to do it
a second time. Useful for platforms that are pre-booted
by coreboot or similar.
Chip has SRIO or not
Board has SRIO 1 port available
Board has SRIO 2 port available
Virtual Address of SRIO port 'n' memory region
Physical Address of SRIO port 'n' memory region
Size of SRIO port 'n' memory region
Defined to tell the NDFC that the NAND chip is using a
16 bit bus.
Sets the EBC0_CFG register for the NDFC. If not defined
a default value will be used.
Get DDR timing information from an I2C EEPROM. Common
with pluggable memory modules such as SODIMMs
I2C address of the SPD EEPROM
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.
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.
Enable interactive DDR debugging. See doc/README.fsl-ddr.
Only for 83xx systems. If specified, then DDR should
be configured using CS0 and CS1 instead of CS2 and CS3.
Define to enable FEC[12] on a 8xx series processor.
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.
The PHY does not have a RXERR line (RMII only).
(so program the FEC to ignore it).
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.
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.
Add the "loopw" memory command. This only takes effect if
the memory commands are activated globally (CONFIG_CMD_MEM).
Add the "mdc" and "mwc" memory commands. These are cyclic
"md/mw" commands.
=> 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).
[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.
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.
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.
If defined, the x86 reset vector code is excluded. You will need
to do this when U-Boot is running from Coreboot.
If defined, x86 real mode code is omitted. This assumes a
32-bit environment where such code is not needed. You will
need to do this when U-Boot is running from Coreboot.
Freescale QE/FMAN Firmware Support:
The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
loading of "firmware", which is encoded in the QE firmware binary format.
This firmware often needs to be loaded during U-Boot booting, so macros
are used to identify the storage device (NOR flash, SPI, etc) and the address
within that device.
The address in the storage device where the firmware is located. The
meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
is also specified.
The maximum possible size of the firmware. The firmware binary format
has a field that specifies the actual size of the firmware, but it
might not be possible to read any part of the firmware unless some
local storage is allocated to hold the entire firmware first.
Specifies that QE/FMAN firmware is located in NOR flash, mapped as
normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
virtual address in NOR flash.
Specifies that QE/FMAN firmware is located in NAND flash.
CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
Specifies that QE/FMAN firmware is located on the primary SD/MMC
device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
Specifies that QE/FMAN firmware is located on the primary SPI
device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
Specifies that QE/FMAN firmware is located in the remote (master)
memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
window->master inbound window->master LAW->the ucode address in
master's memory space.
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
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-
Note: If you wish to generate Windows versions of the utilities in
the tools directory you can use the MinGW toolchain
( 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 boards.cfg 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
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
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
1. Add a new configuration option for your board to the toplevel
"boards.cfg" file, using the existing entries as examples.
Follow the instructions there to keep the boards in 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 "".
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
or to build on a native PowerPC system you can type
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
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
bootz - boot zImage from memory
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
nand - NAND memory operations (see doc/README.nand)
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:
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
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 - 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
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
fdt_high - if set this restricts the maximum address that the
flattened device tree will be copied into upon boot.
For example, if you have a system with 1 GB memory
at physical address 0x10000000, while Linux kernel
only recognizes the first 704 MB as low memory, you
may need to set fdt_high as 0x3C000000 to have the
device tree blob be copied to the maximum address
of the 704 MB low memory, so that Linux kernel can
access it during the boot procedure.
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
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 # traffic sent on FEC
=> setenv ethact SCC
=> ping # 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
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
Please note that changes to some configuration parameters may take
only effect after the next boot (yes, that's just like Windoze :-).
Callback functions for environment variables:
For some environment variables, the behavior of u-boot needs to change
when their values are changed. This functionailty allows functions to
be associated with arbitrary variables. On creation, overwrite, or
deletion, the callback will provide the opportunity for some side
effect to happen or for the change to be rejected.
The callbacks are named and associated with a function using the
U_BOOT_ENV_CALLBACK macro in your board or driver code.
These callbacks are associated with variables in one of two ways. The