releases in "stable" maintenance trees.
Examples:
- U-Boot v2009.11 - Release November 2009
+ 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
/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
must be defined, to setup the maximum idle timeout for
the SMC.
+- Pre-Console Buffer:
+ Prior to the console being initialised (i.e. serial UART
+ initialised etc) all console output is silently discarded.
+ Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
+ buffer any console messages prior to the console being
+ initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
+ bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
+ a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
+ bytes are output before the console is initialised, the
+ earlier bytes are discarded.
+
+ 'Sane' compilers will generate smaller code if
+ CONFIG_PRE_CON_BUF_SZ is a power of 2
+
- Boot Delay: CONFIG_BOOTDELAY - in seconds
Delay before automatically booting the default image;
set to -1 to disable autoboot.
CONFIG_CMD_NAND * NAND support
CONFIG_CMD_NET bootp, tftpboot, rarpboot
CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
- CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
+ CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
CONFIG_CMD_PCI * pciinfo
CONFIG_CMD_PCMCIA * PCMCIA support
CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
CONFIG_CMD_SOURCE "source" command Support
CONFIG_CMD_SPI * SPI serial bus support
CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
+ CONFIG_CMD_TFTPPUT * TFTP put command (upload)
+ CONFIG_CMD_TIME * run command and report execution time
CONFIG_CMD_USB * USB support
CONFIG_CMD_CDP * Cisco Discover Protocol support
CONFIG_CMD_FSL * Microblaze FSL support
XXX - this list needs to get updated!
+- Device tree:
+ CONFIG_OF_CONTROL
+ If this variable is defined, U-Boot will use a device tree
+ to configure its devices, instead of relying on statically
+ compiled #defines in the board file. This option is
+ experimental and only available on a few boards. The device
+ tree is available in the global data as gd->fdt_blob.
+
+ U-Boot needs to get its device tree from somewhere. This can
+ be done using one of the two options below:
+
+ CONFIG_OF_EMBED
+ If this variable is defined, U-Boot will embed a device tree
+ binary in its image. This device tree file should be in the
+ board directory and called <soc>-<board>.dts. The binary file
+ is then picked up in board_init_f() and made available through
+ the global data structure as gd->blob.
+
+ CONFIG_OF_SEPARATE
+ If this variable is defined, U-Boot will build a device tree
+ binary. It will be called u-boot.dtb. Architecture-specific
+ code will locate it at run-time. Generally this works by:
+
+ cat u-boot.bin u-boot.dtb >image.bin
+
+ and in fact, U-Boot does this for you, creating a file called
+ u-boot-dtb.bin which is useful in the common case. You can
+ still use the individual files if you need something more
+ exotic.
+
- Watchdog:
CONFIG_WATCHDOG
If this variable is defined, it enables watchdog
CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
- CONFIG_RTC_MC13783 - use MC13783 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
- NETWORK Support (PCI):
CONFIG_E1000
- Support for Intel 8254x gigabit chips.
+ Support for Intel 8254x/8257x gigabit chips.
+
+ CONFIG_E1000_SPI
+ Utility code for direct access to the SPI bus on Intel 8257x.
+ This does not do anything useful unless you set at least one
+ of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
+
+ CONFIG_E1000_SPI_GENERIC
+ Allow generic access to the SPI bus on the Intel 8257x, for
+ example with the "sspi" command.
+
+ CONFIG_CMD_E1000
+ Management command for E1000 devices. When used on devices
+ with SPI support you can reprogram the EEPROM from U-Boot.
CONFIG_E1000_FALLBACK_MAC
default MAC for empty EEPROM after production.
Define this to use i/o functions instead of macros
(some hardware wont work with macros)
+ CONFIG_DRIVER_TI_EMAC
+ Support for davinci emac
+
+ CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
+ Define this if you have more then 3 PHYs.
+
CONFIG_FTGMAC100
Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
to disable the command chpart. This is the default when you
have not defined a custom partition
+- FAT(File Allocation Table) filesystem write function support:
+ CONFIG_FAT_WRITE
+ Support for saving memory data as a file
+ in FAT formatted partition
+
- Keyboard Support:
CONFIG_ISA_KEYBOARD
or CONFIG_VIDEO_SED13806_16BPP
CONFIG_FSL_DIU_FB
- Enable the Freescale DIU video driver. Reference boards for
+ 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:
Define a default value for the IP address to use for
the default Ethernet interface, in case this is not
determined through e.g. bootp.
+ (Environment variable "ipaddr")
- Server IP address:
CONFIG_SERVERIP
Defines a default value for the IP address of a TFTP
server to contact when using the "tftboot" command.
+ (Environment variable "serverip")
CONFIG_KEEP_SERVERADDR
Keeps the server's MAC address, in the env 'serveraddr'
for passing to bootargs (like Linux's netconsole option)
+- Gateway IP address:
+ CONFIG_GATEWAYIP
+
+ Defines a default value for the IP address of the
+ default router where packets to other networks are
+ sent to.
+ (Environment variable "gatewayip")
+
+- Subnet mask:
+ CONFIG_NETMASK
+
+ Defines a default value for the subnet mask (or
+ routing prefix) which is used to determine if an IP
+ address belongs to the local subnet or needs to be
+ forwarded through a router.
+ (Environment variable "netmask")
+
- Multicast TFTP Mode:
CONFIG_MCAST_TFTP
CONFIG_I2C_MULTI_BUS
This option allows the use of multiple I2C buses, each of which
- must have a controller. At any point in time, only one bus is
- active. To switch to a different bus, use the 'i2c dev' command.
+ must have a controller. At any point in time, only one bus is
+ active. To switch to a different bus, use the 'i2c dev' command.
Note that bus numbering is zero-based.
CONFIG_SYS_I2C_NOPROBES
This option specifies a list of I2C devices that will be skipped
- when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
+ when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
is set, specify a list of bus-device pairs. Otherwise, specify
a 1D array of device addresses
e.g.
#undef CONFIG_I2C_MULTI_BUS
- #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
+ #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
will skip addresses 0x50 and 0x68 on a board with one I2C bus
- #define CONFIG_I2C_MULTI_BUS
+ #define CONFIG_I2C_MULTI_BUS
#define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
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
+ Currently supported on some MPC8xxx processors. For an
example, see include/configs/mpc8349emds.h.
CONFIG_MXC_SPI
Enables the driver for the SPI controllers on i.MX and MXC
- SoCs. Currently only i.MX31 is supported.
+ SoCs. Currently i.MX31/35/51 are supported.
- FPGA Support: CONFIG_FPGA
example, some LED's) on your board. At the moment,
the following checkpoints are implemented:
-- Standalone program support:
- CONFIG_STANDALONE_LOAD_ADDR
-
- This option allows to define board specific values
- for the address where standalone program gets loaded,
- thus overwriting the architecutre dependent default
- settings.
-
-- Frame Buffer Address:
- CONFIG_FB_ADDR
-
- Define CONFIG_FB_ADDR if you want to use specific address for
- frame buffer.
- Then system will reserve the frame buffer address to defined address
- instead of lcd_setmem (this function grab the memory for frame buffer
- by panel's size).
-
- Please see board_init_f function.
-
- If you want this config option then,
- please define it at your board config file
-
Legacy uImage format:
Arg Where When
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
+ 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()
-150 common/cmd_nand.c Incorrect FIT image format
151 common/cmd_nand.c FIT image format OK
+- Standalone program support:
+ CONFIG_STANDALONE_LOAD_ADDR
+
+ This option defines a board specific value for the
+ address where standalone program gets loaded, thus
+ overwriting the architecture dependent default
+ settings.
+
+- Frame Buffer Address:
+ CONFIG_FB_ADDR
+
+ Define CONFIG_FB_ADDR if you want to use specific
+ address for frame buffer.
+ Then system will reserve the frame buffer address to
+ defined address instead of lcd_setmem (this function
+ grabs the memory for frame buffer by panel's size).
+
+ Please see board_init_f function.
+
- Automatic software updates via TFTP server
CONFIG_UPDATE_TFTP
CONFIG_UPDATE_TFTP_CNT_MAX
kernel. Needed for UBI support.
- SPL framework
- CONFIG_SPL
- Enable building of SPL globally.
+ CONFIG_SPL
+ Enable building of SPL globally.
- CONFIG_SPL_TEXT_BASE
- TEXT_BASE for linking the SPL binary.
+ CONFIG_SPL_TEXT_BASE
+ TEXT_BASE for linking the SPL binary.
- CONFIG_SPL_LDSCRIPT
- LDSCRIPT for linking the SPL binary.
+ CONFIG_SPL_LDSCRIPT
+ LDSCRIPT for linking the SPL binary.
- CONFIG_SPL_LIBCOMMON_SUPPORT
- Support for common/libcommon.o in SPL binary
+ CONFIG_SPL_LIBCOMMON_SUPPORT
+ Support for common/libcommon.o in SPL binary
- CONFIG_SPL_LIBDISK_SUPPORT
- Support for disk/libdisk.o in SPL binary
+ CONFIG_SPL_LIBDISK_SUPPORT
+ Support for disk/libdisk.o in SPL binary
- CONFIG_SPL_I2C_SUPPORT
- Support for drivers/i2c/libi2c.o in SPL binary
+ CONFIG_SPL_I2C_SUPPORT
+ Support for drivers/i2c/libi2c.o in SPL binary
- CONFIG_SPL_GPIO_SUPPORT
- Support for drivers/gpio/libgpio.o in SPL binary
+ CONFIG_SPL_GPIO_SUPPORT
+ Support for drivers/gpio/libgpio.o in SPL binary
- CONFIG_SPL_MMC_SUPPORT
- Support for drivers/mmc/libmmc.o in SPL binary
+ CONFIG_SPL_MMC_SUPPORT
+ Support for drivers/mmc/libmmc.o in SPL binary
- CONFIG_SPL_SERIAL_SUPPORT
- Support for drivers/serial/libserial.o in SPL binary
+ CONFIG_SPL_SERIAL_SUPPORT
+ Support for drivers/serial/libserial.o in SPL binary
- CONFIG_SPL_SPI_FLASH_SUPPORT
- Support for drivers/mtd/spi/libspi_flash.o in SPL binary
+ CONFIG_SPL_SPI_FLASH_SUPPORT
+ Support for drivers/mtd/spi/libspi_flash.o in SPL binary
- CONFIG_SPL_SPI_SUPPORT
- Support for drivers/spi/libspi.o in SPL binary
+ CONFIG_SPL_SPI_SUPPORT
+ Support for drivers/spi/libspi.o in SPL binary
- CONFIG_SPL_FAT_SUPPORT
- Support for fs/fat/libfat.o in SPL binary
+ CONFIG_SPL_FAT_SUPPORT
+ Support for fs/fat/libfat.o in SPL binary
- CONFIG_SPL_LIBGENERIC_SUPPORT
- Support for lib/libgeneric.o in SPL binary
+ CONFIG_SPL_LIBGENERIC_SUPPORT
+ Support for lib/libgeneric.o in SPL binary
Modem Support:
--------------
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:
-----------------------
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
+ and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
variable "bootm_mapsize" will override the value of
CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
then the value in "bootm_size" will be used instead.
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
+ during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
aligned to an erase block boundary.
- CONFIG_ENV_RANGE (optional):
and RPXsuper) to be able to adjust the position of
the IMMR register after a reset.
+- CONFIG_SYS_CCSRBAR_DEFAULT:
+ Default (power-on reset) physical address of CCSR on Freescale
+ PowerPC SOCs.
+
+- CONFIG_SYS_CCSRBAR:
+ Virtual address of CCSR. On a 32-bit build, this is typically
+ the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
+
+ CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
+ for cross-platform code that uses that macro instead.
+
+- CONFIG_SYS_CCSRBAR_PHYS:
+ Physical address of CCSR. CCSR can be relocated to a new
+ physical address, if desired. In this case, this macro should
+ be set to that address. Otherwise, it should be set to the
+ same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
+ is typically relocated on 36-bit builds. It is recommended
+ that this macro be defined via the _HIGH and _LOW macros:
+
+ #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
+ * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
+
+- CONFIG_SYS_CCSRBAR_PHYS_HIGH:
+ Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
+ either 0 (32-bit build) or 0xF (36-bit build). This macro is
+ used in assembly code, so it must not contain typecasts or
+ integer size suffixes (e.g. "ULL").
+
+- CONFIG_SYS_CCSRBAR_PHYS_LOW:
+ Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
+ used in assembly code, so it must not contain typecasts or
+ integer size suffixes (e.g. "ULL").
+
+- CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
+ If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
+ forced to a value that ensures that CCSR is not relocated.
+
- Floppy Disk Support:
CONFIG_SYS_FDC_DRIVE_NUMBER
parameters are extracted from datasheet and hard-coded into
header files or board specific files.
+- CONFIG_FSL_DDR_INTERACTIVE
+ Enable interactive DDR debugging. See doc/README.fsl-ddr.
+
- CONFIG_SYS_83XX_DDR_USES_CS0
Only for 83xx systems. If specified, then DDR should
be configured using CS0 and CS1 instead of CS2 and CS3.
globally (CONFIG_CMD_MEM).
- CONFIG_SKIP_LOWLEVEL_INIT
- [ARM, MIPS only] If this variable is defined, then certain
+ [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.
that is executed before the actual U-Boot. E.g. when
compiling a NAND SPL.
+- CONFIG_SYS_NAND_HW_ECC_OOBFIRST
+ define this, if you want to read first the oob data
+ and then the data. This is used for example on
+ davinci plattforms.
+
- CONFIG_USE_ARCH_MEMCPY
CONFIG_USE_ARCH_MEMSET
If these options are used a optimized version of memcpy/memset will
be used if available. These functions may be faster under some
conditions but may increase the binary size.
+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.
+
+- CONFIG_SYS_QE_FMAN_FW_ADDR
+ 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.
+
+- CONFIG_SYS_QE_FMAN_FW_LENGTH
+ 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.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_NOR
+ 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.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_NAND
+ Specifies that QE/FMAN firmware is located in NAND flash.
+ CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_MMC
+ 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.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
+ Specifies that QE/FMAN firmware is located on the primary SPI
+ device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
+
+
Building the Software:
======================
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
kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
bootm_mapsize.
- bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
+ 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
add the information it needs into it, and the memory
must be accessible by the kernel.
+ fdtcontroladdr- if set this is the address of the control flattened
+ device tree used by U-Boot when CONFIG_OF_CONTROL is
+ defined.
+
i2cfast - (PPC405GP|PPC405EP only)
if set to 'y' configures Linux I2C driver for fast
mode (400kHZ). This environment variable is used in
bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
- ethprime - When CONFIG_NET_MULTI is enabled controls which
- interface is used first.
+ ethprime - controls which interface is used first.
- ethact - When CONFIG_NET_MULTI is enabled controls which
- interface is currently active. For example you
- can do the following
+ ethact - controls which interface is currently active.
+ For example you can do the following
=> setenv ethact FEC
=> ping 192.168.0.1 # traffic sent on FEC
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:
is raised.
If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
-will be programmed into hardware as part of the initialization process. This
+will be programmed into hardware as part of the initialization process. This
may be skipped by setting the appropriate 'ethmacskip' environment variable.
The naming convention is as follows:
"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
INTEGRITY).
* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
- IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
- Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
+ IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
+ Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
* Compression Type (uncompressed, gzip, bzip2)
* Load Address
* Entry Point
Note: on Nios II, we give "-G0" option to gcc and don't use gp
to access small data sections, so gp is free.
+On NDS32, the following registers are used:
+
+ R0-R1: argument/return
+ R2-R5: argument
+ R15: temporary register for assembler
+ R16: trampoline register
+ R28: frame pointer (FP)
+ R29: global pointer (GP)
+ R30: link register (LP)
+ R31: stack pointer (SP)
+ PC: program counter (PC)
+
+ ==> U-Boot will use R10 to hold a pointer to the global data
+
NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
or current versions of GCC may "optimize" the code too much.
projects / karo-tx-uboot.git / blobdiff