BananaPi with Arch Linux ARM and a mainline kernel

I posted a guide on getting Arch Linux ARM on the BananaPi last week. Now I was eager to get a mainline kernel working on the BananaPi for some ARM hacking and testing of new patches. In this post I'll describe the steps required to get a mainline kernel booted next to the "normal" kernel.

Compiling mainline kernel

I am using Hans de Goede's branch here, since he has some patches for USB OTG support for the BananP in there. But the normal mainline kernel should work with similiar steps

git clone https://github.com/jwrdegoede/linux-sunxi.git
cd linux-sunxi
git checkout -B sunxi-wip origin/sunxi-wip

wget https://fedorapeople.org/~jwrdegoede/kernel-driver-programming/kernel-config
mv kernel-config .config
# CROSS_COMPILE may differ per distro. arm-linux-gnu- probably works for the other distro's.
make -j4 ARCH=arm CROSS_COMPILE=arm-none-eabi- oldconfig
make -j4 ARCH=arm CROSS_COMPILE=arm-none-eabi- dtbs
make -j4 ARCH=arm CROSS_COMPILE=arm-none-eabi- zImage

Now that we have a kernel compiled, mount the sdcard.

mount /dev/sdX1 mnt

cp /path/to/linux-sunxi/arch/arm/boot/zImage mnt/boot/zImagemainline

mkdir mnt/boot/dtbsmainline
cp /path/to/linux-sunxi/arch/arm/boot/dts/*.dtb mnt/boot/dtbsmainline/
umount /dev/sdX1
sync

Now that we have copied the mainline kernel and dts files to the sdcard, it still won't boot it. Since the boot.scr is specified to look dts/* and zImage. So we will need to copy a new scr file. (note that you cannot edit the scr file on the sdcard) You can either generate a new scr file or create on yourself!

mount /dev/sdX1 mnt
wget http://pkgbuild.com/~jelle/bananapi/boot-mainline.scr -O mnt/boot/boot.scr
umount /dev/sdX1
sync

Or generate a new scr file, which sounds more fun.

pacman -S uboot-tools

wget http://pkgbuild.com/~jelle/bananapi/boot.cmd
mkimage -A arm -O linux -T script -C none -a 0 -e 0 -n "BananPI boot script" -d boot.cmd boot.scr

mount /dev/sdX1 mnt
cp boot.scr mnt/boot/boot.scr
umount /dev/sdX1
sync

I haven't figured out what the boot.scr exactly does or if there is a way to specify which kernel to boot with one boot.scr file.

So expect some more posts while I explore more about U-boot and ARM :-)