booting the samsung chromeboot xe303c12 with the debian armmp kernel

[Pedro Bulach <pedrobulach@gmail.com>]

Hello to all,

I have been trying to boot debian's kernel vmlinuz-3.16-3-armmp on the
samsung xe303c12 chromebook. Based on bug #759291 there is now support
for the exynos in the kernel.

Currently I can boot with the chos kernel, but I have not yet been
able to boot with the debian kernel, so I turn to the list for help
and/or advice.

The setup is as follows (on a usb stick):
 * chromeos kernel is on partition 1
 * nv_uboot-snow-simplefb.kpart is on partition 2 and marked and higher priority
 * the following 3 partitions are /boot, / and /home
 * flash-kernel is installed and configured as follows:
cat machine
Google Snow
cat db
Machine: Google Snow
Kernel-Flavors: armmp armmp-lpae
DTB-Id: exynos5250-snow.dtb
Boot-Script-Path: /boot/boot.scr
U-Boot-Script-Name: bootscr.uboot-generic
Required-Packages: u-boot-tools
 * linux-image-armmp is installed
 * exynos5250-snow.dtb has been copied to /boot

I have generated u-boot images as follows:
mkimage -A arm -O linux -T kernel -C none -a 0x42000000 -e 0x42000000
-n "debian kernel" -d vmlinuz-3.16-3-armmp uImage
mkimage -A arm -O linux -T ramdisk -C none -a 0x45000000 -e 0x45000000
-n "initramfs" -d initrd.img-3.16-3-armmp initrd
cat << __EOF__ > boot.txt
setenv bootargs 'cros_legacy console=ttySAC3,115200 debug earlyprintk
root=/dev/sda4 rootfstype=ext4 rootwait rw'
setenv ext2_boot 'usb start; usb dev 0; ext2load usb 0:3 ${loadaddr}
uImage; ext2load usb 0:3 ${initrdaddr} initrd; ext2load usb 0:3
${dtaddr} exynos5250-snow.dtb; bootm ${loadaddr} ${initrdaddr}
${dtaddr}'
setenv bootcmd run ext2_boot
__EOF__
mkimage -A arm -C none -T script -d boot.txt boot.scr

The pending issues are the following:
 1. nv u-boot does not load by boot command file
 2. at the u-boot prompt, I can load the uImage, initrd and dtb,
followed by a bootm command, but the system hangs and I do not see any
kernel messages

Finally, I have a few doubts:
Is this config/kernel supposed to work on this hw?
Where can I find flash-kernel docs to configure it correctly to
automate this process? (supposing I will make this work)

Any corrections to my current setup will be much appreciated :-)

Regards,

Pedro