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## SECTION=bootloader
menuconfig AT91BOOTSTRAP
bool
depends on ARCH_ARM
prompt "AT91 bootstrap "
help
The AT91Bootstrap application is a first level bootloader
for Atmel AT91SAM9 ARM Thumb-based microcontrollers.
It is used for booting these microcontrollers from SPI dataflash
or NAND-flash.
For example, using this bootstrap, it is possible to
obtain a basic bootloader that is located in DataFlash and is
copied to internal SRAM by SAM-BA Boot (internal bootROM). The
bootloader performs the processor initialization (PLLs, PIOs,
SDRAMC, SPI), loads UBoot from DataFlash sectors to SDRAM and
then jumps to it.
It is required for these microcontrollers, because the bootROM of some
of these cores can only handle a miximum of 4kB of the 1st stage
bootloader (e.g. SRAM limits). U-boot is usually much larger
than this.
U-boot is normally build with the options CONFIG_SKIP_LOWLEVEL_INIT
and CONFIG_SKIP_RELOCATE_UBOOT
AT91Bootstrap integrates several sets of algorithms:
- Device initialization such as clock speed configuration, PIO settings, etc.
- Peripheral drivers such as PIO, PMC, SDRAMC, etc.
- Physical media algorithms such as DataFlash, NANDFlash, Parallel Flash, etc.
if AT91BOOTSTRAP
config AT91BOOTSTRAP_VERSION
string
default 1.16
prompt "AT91 Bootstrap version"
help
Enter the AT91 Bootstrap version you want to build. Usally something like "1.11"
config AT91BOOTSTRAP_MD5
prompt "AT91 Bootstrap source md5sum"
string
config AT91BOOTSTRAP_CONFIG
string
prompt "AT91 Bootstrap config target"
default "at91sam9261ek"
help
The AT91 Bootstrap make config target. Usually something like
"at91sam9261ek". See AT91 Bootstrap's 'board' directory for possible
configuration targets.
choice
prompt "Boot medium"
default AT91BOOTSTRAP_BOOT_DATAFLASH
config AT91BOOTSTRAP_BOOT_DATAFLASH
bool
prompt "SPI dataflash"
config AT91BOOTSTRAP_BOOT_NAND
bool
prompt "NAND flash"
endchoice
endif
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