1 files changed, 93 insertions, 0 deletions
diff --git a/doc/README.hawkboard b/doc/README.hawkboard
new file mode 100644
index 0000000..b7afec4
--- /dev/null
+++ b/doc/README.hawkboard
@@ -0,0 +1,93 @@
+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 nand_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(nand_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 nand_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
+
+* nand_spl - This is the secondary bootloader which boots the u-boot
+  binary.
+
+  hawkboard_nand_config
+
+  The nand_spl ELF gets generated under nand_spl/u-boot-spl. This
+  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 binary - This is the image flashed to the nand and copied to
+  the memory by the nand_spl.
+
+  hawkboard_config
+
+* 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 nand_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 nand_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 nand_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