|
|
|
|
Summary
|
|
|
|
|
=======
|
|
|
|
|
The README is for the boot procedure used for TI's OMAP-L138 based
|
|
|
|
|
hawkboard. The hawkboard comes with a 128MiB Nand flash and a 128MiB
|
|
|
|
|
DDR SDRAM along with a host of other controllers.
|
|
|
|
|
|
|
|
|
|
The hawkboard is booted in three stages. The initial bootloader which
|
|
|
|
|
executes upon reset is the Rom Boot Loader(RBL) which sits in the
|
|
|
|
|
internal ROM of the omap. The RBL initialises the memory and the nand
|
|
|
|
|
controller, and copies the image stored at a predefined location(block
|
|
|
|
|
1) of the nand flash. The image loaded by the RBL to the memory is the
|
|
|
|
|
AIS signed spl image. This, in turns copies the u-boot binary from the
|
|
|
|
|
nand flash to the memory and jumps to the u-boot entry point.
|
|
|
|
|
|
|
|
|
|
AIS is an image format defined by TI for the images that are to be
|
|
|
|
|
loaded to memory by the RBL. The image is divided into a series of
|
|
|
|
|
sections and the image's entry point is specified. Each section comes
|
|
|
|
|
with meta data like the target address the section is to be copied to
|
|
|
|
|
and the size of the section, which is used by the RBL to load the
|
|
|
|
|
image. At the end of the image the RBL jumps to the image entry
|
|
|
|
|
point.
|
|
|
|
|
|
|
|
|
|
The secondary stage bootloader(spl) which is loaded by the RBL then
|
|
|
|
|
loads the u-boot from a predefined location in the nand to the memory
|
|
|
|
|
and jumps to the u-boot entry point.
|
|
|
|
|
|
|
|
|
|
The reason a secondary stage bootloader is used is because the ECC
|
|
|
|
|
layout expected by the RBL is not the same as that used by
|
|
|
|
|
u-boot/linux. This also implies that for flashing the spl image,we
|
|
|
|
|
need to use the u-boot which uses the ECC layout expected by the
|
|
|
|
|
RBL[1]. Booting u-boot over UART(UART boot) is explained here[2].
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Compilation
|
|
|
|
|
===========
|
|
|
|
|
Three images might be needed
|
|
|
|
|
|
|
|
|
|
* spl - This is the secondary bootloader which boots the u-boot
|
|
|
|
|
binary.
|
|
|
|
|
|
|
|
|
|
* u-boot binary - This is the image flashed to the nand and copied to
|
|
|
|
|
the memory by the spl.
|
|
|
|
|
|
|
|
|
|
Both the images get compiled with hawkboard_config, with the TOPDIR
|
|
|
|
|
containing the u-boot images, and the spl image under the spl
|
|
|
|
|
directory.
|
|
|
|
|
|
|
|
|
|
The spl image needs to be processed with the AISGen tool for
|
|
|
|
|
generating the AIS signed image to be flashed. Steps for generating
|
|
|
|
|
the AIS image are explained here[3].
|
|
|
|
|
|
|
|
|
|
* u-boot for uart boot - This is same as the u-boot binary generated
|
|
|
|
|
above, with the sole difference of the CONFIG_SYS_TEXT_BASE being
|
|
|
|
|
0xc1080000, as expected by the RBL.
|
|
|
|
|
|
|
|
|
|
hawkboard_uart_config
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Flashing the images to Nand
|
|
|
|
|
===========================
|
|
|
|
|
The spl AIS image needs to be flashed to the block 1 of the Nand
|
|
|
|
|
flash, as that is the location the RBL expects the image[4]. For
|
|
|
|
|
flashing the spl, boot over the u-boot specified in [1], and flash the
|
|
|
|
|
image
|
|
|
|
|
|
|
|
|
|
=> tftpboot 0xc0700000 <nand_spl_ais.bin>
|
|
|
|
|
=> nand erase 0x20000 0x20000
|
|
|
|
|
=> nand write.e 0xc0700000 0x20000 <nand_spl_size>
|
|
|
|
|
|
|
|
|
|
The u-boot binary is flashed at location 0xe0000(block 6) of the nand
|
|
|
|
|
flash. The spl loader expects the u-boot at this location. For
|
|
|
|
|
flashing the u-boot binary
|
|
|
|
|
|
|
|
|
|
=> tftpboot 0xc0700000 u-boot.bin
|
|
|
|
|
=> nand erase 0xe0000 0x40000
|
|
|
|
|
=> nand write.e 0xc0700000 0xe0000 <u-boot-size>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Links
|
|
|
|
|
=====
|
|
|
|
|
|
|
|
|
|
[1]
|
|
|
|
|
http://code.google.com/p/hawkboard/downloads/detail?name=u-boot_uart_ais_v1.bin
|
|
|
|
|
|
|
|
|
|
[2]
|
|
|
|
|
http://elinux.org/Hawkboard#Booting_u-boot_over_UART
|
|
|
|
|
|
|
|
|
|
[3]
|
|
|
|
|
http://elinux.org/Hawkboard#Signing_u-boot_for_UART_boot
|
|
|
|
|
|
|
|
|
|
[4]
|
|
|
|
|
http://processors.wiki.ti.com/index.php/RBL_UBL_and_host_program#RBL_booting_from_NAND_and_ECC.2FBad_blocks
|
