U-Boot, you should send a message to the U-Boot mailing list at
<u-boot@lists.denx.de>. There is also an archive of previous traffic
on the mailing list - please search the archive before asking FAQ's.
-Please see http://lists.denx.de/pipermail/u-boot and
-http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
-
+Please see https://lists.denx.de/pipermail/u-boot and
+https://marc.info/?l=u-boot
Where to get source code:
=========================
The U-Boot source code is maintained in the Git repository at
-git://www.denx.de/git/u-boot.git ; you can browse it online at
-http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
+https://gitlab.denx.de/u-boot/u-boot.git ; you can browse it online at
+https://gitlab.denx.de/u-boot/u-boot
-The "snapshot" links on this page allow you to download tarballs of
+The "Tags" links on this page allow you to download tarballs of
any version you might be interested in. Official releases are also
-available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
-directory.
-
-Pre-built (and tested) images are available from
-ftp://ftp.denx.de/pub/u-boot/images/
+available from the DENX file server through HTTPS or FTP.
+https://ftp.denx.de/pub/u-boot/
+ftp://ftp.denx.de/pub/u-boot/
Where we come from:
===================
- start from 8xxrom sources
-- create PPCBoot project (http://sourceforge.net/projects/ppcboot)
+- create PPCBoot project (https://sourceforge.net/projects/ppcboot)
- clean up code
- make it easier to add custom boards
- make it possible to add other [PowerPC] CPUs
* S-Record download
* network boot
* ATA disk / SCSI ... boot
-- create ARMBoot project (http://sourceforge.net/projects/armboot)
+- create ARMBoot project (https://sourceforge.net/projects/armboot)
- add other CPU families (starting with ARM)
-- create U-Boot project (http://sourceforge.net/projects/u-boot)
-- current project page: see http://www.denx.de/wiki/U-Boot
+- create U-Boot project (https://sourceforge.net/projects/u-boot)
+- current project page: see https://www.denx.de/wiki/U-Boot
Names and Spelling:
/mips Files generic to MIPS architecture
/nds32 Files generic to NDS32 architecture
/nios2 Files generic to Altera NIOS2 architecture
- /openrisc Files generic to OpenRISC architecture
/powerpc Files generic to PowerPC architecture
/riscv Files generic to RISC-V architecture
/sandbox Files generic to HW-independent "sandbox"
/sh Files generic to SH architecture
/x86 Files generic to x86 architecture
+ /xtensa Files generic to Xtensa architecture
/api Machine/arch independent API for external apps
/board Board dependent files
/cmd U-Boot commands functions
/doc Documentation (don't expect too much)
/drivers Commonly used device drivers
/dts Contains Makefile for building internal U-Boot fdt.
+/env Environment files
/examples Example code for standalone applications, etc.
/fs Filesystem code (cramfs, ext2, jffs2, etc.)
/include Header Files
specific to be undertaken on a native platform. The sandbox is also used to
run some of U-Boot's tests.
-See doc/arch/index.rst for more details.
+See doc/arch/sandbox.rst for more details.
Board Initialisation Flow:
version as needed.
- preloader_console_init() can be called here in extremis
- should set up SDRAM, and anything needed to make the UART work
- - these is no need to clear BSS, it will be done by crt0.S
+ - there is no need to clear BSS, it will be done by crt0.S
- for specific scenarios on certain architectures an early BSS *can*
be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
of BSS prior to entering board_init_f()) but doing so is discouraged.
such as ARM architectural timer initialization.
- Linux Kernel Interface:
- CONFIG_CLOCKS_IN_MHZ
-
- U-Boot stores all clock information in Hz
- internally. For binary compatibility with older Linux
- kernels (which expect the clocks passed in the
- bd_info data to be in MHz) the environment variable
- "clocks_in_mhz" can be defined so that U-Boot
- converts clock data to MHZ before passing it to the
- Linux kernel.
- When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
- "clocks_in_mhz=1" is automatically included in the
- default environment.
-
CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
When transferring memsize parameter to Linux, some versions
This setting is mandatory for all boards that have only one
machine type and must be used to specify the machine type
number as it appears in the ARM machine registry
- (see http://www.arm.linux.org.uk/developer/machines/).
+ (see https://www.arm.linux.org.uk/developer/machines/).
Only boards that have multiple machine types supported
in a single configuration file and the machine type is
runtime discoverable, do not have to use this setting.
serverip, gatewayip, hostname, othbootargs.
It loads the vxWorks image pointed bootfile.
- Note: If a "bootargs" environment is defined, it will overwride
+ Note: If a "bootargs" environment is defined, it will override
the defaults discussed just above.
- Cache Configuration:
Define this variable to enable hw flow control in serial driver.
Current user of this option is drivers/serial/nsl16550.c driver
-- Console Baudrate:
- CONFIG_BAUDRATE - in bps
- Select one of the baudrates listed in
- CONFIG_SYS_BAUDRATE_TABLE, see below.
-
- Autoboot Command:
CONFIG_BOOTCOMMAND
Only needed when CONFIG_BOOTDELAY is enabled;
Allow generic access to the SPI bus on the Intel 8257x, for
example with the "sspi" command.
- CONFIG_EEPRO100
- Support for Intel 82557/82559/82559ER chips.
- Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
- write routine for first time initialisation.
-
- CONFIG_TULIP
- Support for Digital 2114x chips.
-
CONFIG_NATSEMI
Support for National dp83815 chips.
Enables an 'i2c edid' command which can read EDID
information over I2C from an attached LCD display.
-- Splash Screen Support: CONFIG_SPLASH_SCREEN
-
- If this option is set, the environment is checked for
- a variable "splashimage". If found, the usual display
- of logo, copyright and system information on the LCD
- is suppressed and the BMP image at the address
- specified in "splashimage" is loaded instead. The
- console is redirected to the "nulldev", too. This
- allows for a "silent" boot where a splash screen is
- loaded very quickly after power-on.
-
- CONFIG_SPLASHIMAGE_GUARD
-
- If this option is set, then U-Boot will prevent the environment
- variable "splashimage" from being set to a problematic address
- (see doc/README.displaying-bmps).
- This option is useful for targets where, due to alignment
- restrictions, an improperly aligned BMP image will cause a data
- abort. If you think you will not have problems with unaligned
- accesses (for example because your toolchain prevents them)
- there is no need to set this option.
-
- CONFIG_SPLASH_SCREEN_ALIGN
-
- If this option is set the splash image can be freely positioned
- on the screen. Environment variable "splashpos" specifies the
- position as "x,y". If a positive number is given it is used as
- number of pixel from left/top. If a negative number is given it
- is used as number of pixel from right/bottom. You can also
- specify 'm' for centering the image.
-
- Example:
- setenv splashpos m,m
- => image at center of screen
-
- setenv splashpos 30,20
- => image at x = 30 and y = 20
-
- setenv splashpos -10,m
- => vertically centered image
- at x = dspWidth - bmpWidth - 9
-
-- Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
-
- If this option is set, additionally to standard BMP
- images, gzipped BMP images can be displayed via the
- splashscreen support or the bmp command.
-
-- Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
-
- If this option is set, 8-bit RLE compressed BMP images
- can be displayed via the splashscreen support or the
- bmp command.
-
-- Compression support:
- CONFIG_GZIP
-
- Enabled by default to support gzip compressed images.
-
- CONFIG_BZIP2
-
- If this option is set, support for bzip2 compressed
- images is included. If not, only uncompressed and gzip
- compressed images are supported.
-
- NOTE: the bzip2 algorithm requires a lot of RAM, so
- the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
- be at least 4MB.
-
- MII/PHY support:
CONFIG_PHY_CLOCK_FREQ (ppc4xx)
CONFIG_BOOTP_NISDOMAIN
CONFIG_BOOTP_BOOTFILESIZE
- CONFIG_BOOTP_SEND_HOSTNAME
CONFIG_BOOTP_NTPSERVER
CONFIG_BOOTP_TIMEOFFSET
CONFIG_BOOTP_VENDOREX
to Link-local IP address configuration if the DHCP server
is not available.
- CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
- to do a dynamic update of a DNS server. To do this, they
- need the hostname of the DHCP requester.
- If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
- of the "hostname" environment variable is passed as
- option 12 to the DHCP server.
-
CONFIG_BOOTP_DHCP_REQUEST_DELAY
A 32bit value in microseconds for a delay between
This enable the NEW i2c subsystem, and 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 or other i2c devices. See
- common/cmd_i2c.c for a description of the command line
- interface.
-
- ported i2c driver to the new framework:
- - drivers/i2c/soft_i2c.c:
- - activate first bus with CONFIG_SYS_I2C_SOFT define
CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
for defining speed and slave address
- activate second bus with I2C_SOFT_DECLARATIONS2 define
parameters from when MMC is being used in raw mode
(for falcon mode)
- CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
- Partition on the MMC to load U-Boot from when the MMC is being
- used in fs mode
-
CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
Filename to read to load U-Boot when reading from filesystem
CONFIG_SPL_SKIP_RELOCATE
Avoid SPL relocation
- CONFIG_SPL_NAND_BASE
- Include nand_base.c in the SPL. Requires
- CONFIG_SPL_NAND_DRIVERS.
-
- CONFIG_SPL_NAND_DRIVERS
- SPL uses normal NAND drivers, not minimal drivers.
-
CONFIG_SPL_NAND_IDENT
SPL uses the chip ID list to identify the NAND flash.
Requires CONFIG_SPL_NAND_BASE.
- CONFIG_SPL_NAND_ECC
- Include standard software ECC in the SPL
-
- CONFIG_SPL_NAND_SIMPLE
- Support for NAND boot using simple NAND drivers that
- expose the cmd_ctrl() interface.
-
CONFIG_SPL_UBI
Support for a lightweight UBI (fastmap) scanner and
loader
- CONFIG_SYS_BAUDRATE_TABLE:
List of legal baudrate settings for this board.
-- CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
- Begin and End addresses of the area used by the
- simple memory test.
-
-- CONFIG_SYS_MEMTEST_SCRATCH:
- Scratch address used by the alternate memory test
- You only need to set this if address zero isn't writeable
-
- CONFIG_SYS_MEM_RESERVE_SECURE
Only implemented for ARMv8 for now.
If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
regular expression. This allows multiple variables to define the same
flags without explicitly listing them for each variable.
-- CONFIG_ENV_ACCESS_IGNORE_FORCE
- 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:
and in many different cross environments. Of course we cannot support
all possibly existing versions of cross development tools in all
(potentially obsolete) versions. In case of tool chain problems we
-recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
+recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
which is extensively used to build and test U-Boot.
If you are not using a native environment, it is assumed that you
mm - memory modify (auto-incrementing)
nm - memory modify (constant address)
mw - memory write (fill)
+ms - memory search
cp - memory copy
cmp - memory compare
crc32 - checksum calculation
downloads succeed with high packet loss rates, or with
unreliable TFTP servers or client hardware.
+ tftpwindowsize - if this is set, the value is used for TFTP's
+ window size as described by RFC 7440.
+ This means the count of blocks we can receive before
+ sending ack to server.
+
vlan - When set to a value < 4095 the traffic over
Ethernet is encapsulated/received over 802.1q
VLAN tagged frames.
CONFIG_NET_RETRY_COUNT, if defined. This value has
precedence over the valu based on CONFIG_NET_RETRY_COUNT.
+ memmatches - Number of matches found by the last 'ms' command, in hex
+
+ memaddr - Address of the last match found by the 'ms' command, in hex,
+ or 0 if none
+
+ mempos - Index position of the last match found by the 'ms' command,
+ in units of the size (.b, .w, .l) of the search
+
+ zbootbase - (x86 only) Base address of the bzImage 'setup' block
+
+ zbootaddr - (x86 only) Address of the loaded bzImage, typically
+ BZIMAGE_LOAD_ADDR which is 0x100000
+
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
Load Address: 0x00000000
Entry Point: 0x00000000
-The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
-option performs the converse operation of the mkimage's second form (the "-d"
-option). Given an image built by mkimage, the dumpimage extracts a "data file"
-from the image:
-
- tools/dumpimage -i image -T type -p position data_file
- -i ==> extract from the 'image' a specific 'data_file'
- -T ==> set image type to 'type'
- -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
-
+The "dumpimage" tool can be used to disassemble or list the contents of images
+built by mkimage. See dumpimage's help output (-h) for details.
Installing a Linux Image:
-------------------------
Unix, I recommend to use C-Kermit for general purpose use (and
especially for kermit binary protocol download ("loadb" command), and
use "cu" for S-Record download ("loads" command). See
-http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
+https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
for help with kermit.
Note: on ARM, only R_ARM_RELATIVE relocations are supported.
On Nios II, the ABI is documented here:
- http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
+ https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
==> U-Boot will use gp to hold a pointer to the global data
while (learning) {
Read the README file in the top level directory;
- Read http://www.denx.de/twiki/bin/view/DULG/Manual;
+ Read https://www.denx.de/wiki/bin/view/DULG/Manual;
Read applicable doc/README.*;
Read the source, Luke;
/* find . -name "*.[chS]" | xargs grep -i <keyword> */
establish some rules. Submissions which do not conform to these rules
may be rejected, even when they contain important and valuable stuff.
-Please see http://www.denx.de/wiki/U-Boot/Patches for details.
+Please see https://www.denx.de/wiki/U-Boot/Patches for details.
Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
see https://lists.denx.de/listinfo/u-boot
git.openpandora.org / pandora-u-boot.git / blobdiff