Revision as of 09:18, 8 December 2017

Download Kernel

You can clone the rockchip kernel repository from github which is kernel 4.4 based:

git clone https://github.com/rockchip-linux/kernel.git

Configure and Build

You will need to use rockchip_linux_defconfig for Linux OS

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- rockchip_linux_defconfig
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4

Then you can get Image/zImage and dtb file.

Install Boot/kernel

We use distro boot in U-Boot, so we need to make a boot partition for U-Boot with kernel image and dtb inside.

mkdir boot
cp arch/arm/boot/dts/rk3036-kylin.dtb boot/rk3036-kylin.dtb
cp arch/arm/boot/zImage boot/

Add extlinux/extlinux.conf for distro boot.

mkdir boot/extlinux

cat >> boot/extlinux/extlinux.conf << EOF
label kernel-4.4
    kernel /zImage
    fdt /rk3036-kylin.dtb
    append  earlyprintk console=tty1 console=ttyS2,115200n8 rw root=PARTUUID=69dad710-2c rootfstype=ext4 init=/sbin/init rootwait 
EOF

Generate ext2fs boot partition

by genext2fs:

genext2fs -b 32768 -B $((32*1024*1024/32768)) -d boot/ -i 8192 -U boot_rk3036.img

According to Rockchip partition definition, you need to flash this image to boot partiton which offset is 0x8000.

sudo rkdeveloptool wl 0x8000   boot_rk3036.img

Then, how to generate boot.img? Please have a look at the following:

Generate fatfs boot partition

Generate boot.img in fatfs

Below commands can generate a fatfs boot.img

dd if=/dev/zero of=boot.img bs=1M count=32
sudo mkfs.fat boot.img
mkdir tmp
sudo mount boot.img tmp/
cp -r boot/* tmp/
umount tmp

Done!

Flash this boot.img to boot partition, which is offset 0x8000 in Rockchip partition definition.

sudo rkdeveloptool wl 0x8000 boot.img

Update boot.img via U-Boot in target

After flash and boot the U-Boot, write the gpt table from default partition table

gpt write mmc 0 $partitions
gpt verify mmc 0 $partitions

connect target to PC and start the ums in command line:

ums mmc 0

We should able to see a device connect to PC, formate and copy data into the partition(dev/sdb6 for example).

cp -r boot/* /media/machine/9F35-9565/

Done!

Boot from U-Boot

If you are using genext2fs to genarate the boot.img, you need write the gpt table in U-Boot command line:

gpt write mmc 0 $partitions

Then boot from eMMC or reset:

boot

If everything is OK, you should able to see the U-Boot log like this:

switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:4...
Found /extlinux/extlinux.conf
Retrieving file: /extlinux/extlinux.conf
reading /extlinux/extlinux.conf
192 bytes read in 4 ms (46.9 KiB/s)
1:      kernel-4.4
Retrieving file: /zImage
reading /zImage
7810312 bytes read in 726 ms (10.3 MiB/s)
append: earlyprintk console=tty1 console=ttyS2,115200n8 rw root=PARTUUID=69dad710-2c rootfstype=ext4 init=/sbin/init rootwait
Retrieving file: /rk3036-kylin.dtb
reading /rk3036-kylin.dtb
23641 bytes read in 6 ms (3.8 MiB/s)
Kernel image @ 0x62000000 [ 0x000000 - 0x772d08 ]
## Flattened Device Tree blob at 61f00000
   Booting using the fdt blob at 0x61f00000
   Loading Device Tree to 7df52000, end 7df5ac58 ... OK

Starting kernel ...

DEBUG Kernel:

if you have some issues on bringup kernel, you can enable the earlyprintk configs for rockchip_linux_defconfig

For example:

cat >> arch/arm/configs/rockchip_linux_defconfig << EOF 
CONFIG_DEBUG_LL=y
CONFIG_DEBUG_RK29_UART2=y
CONFIG_EARLY_PRINTK=y
EOF