Kernel Porting and Configuration

Kernel Porting

The zipped kernel linux-sunxi-sunxi-3.4.61.tar.gz can be found on linux-sunxi-sunxi-3.4.61.tar.gz, the kernel config file can be found on cubieboard2_defconfig Or can be obtained from the internet: https://github.com/linux-sunxi/linux-sunxi/releases , To avoid unexpected error while porting, please download the 3.4.61 version kernel.

Extract the kernel source code

Assume that the source code was placed under /home/waveshare/cubieboard2/kernel directory, use the following command to extract it:

#cd /home/waveshare/cubieboard2/kernel
#tar -xzvf linux-sunxi-sunxi-3.4.61.tar.gz

Now we get the original linux-sunxi-sunxi-3.4.61 source code, rename it as linux-sunxi-sunxi-3.4.61_A20, as shown in the picture below:

Assign the cross compiler

Modify the Makefile under root directory:

#cd linux-sunxi-sunxi-3.4.61_A20
#vi Makefile

Edit the following lines:

export KBUILD_BUILDHOST := $(SUBARCH) 
ARCH   ?= $(SUBARCH) 
CROSS_COMPILE ?=

As:

export KBUILD_BUILDHOST := $(SUBARCH)
ARCH        ?= arm
CROSS_COMPILE   ?= arm-linux-gnueabihf-

ARCH specifies the target platform as arm, CROSS_COMPILE assigns the cross compile tool chain. As shown in the picture below:

Note: the vim editor is recommended.

Clear the temp files

Under the root directory, enter:

#make clean

Copy the default config file

Under the root directory, enter:

# cp ../cubieboard2_defconfig .config

A hidden .config file will be generated under the root directory.

Config the kernel

Under the root directory, enter:

#make menuconfig

Config the kernel on the popup window, as shown in the picture below:

Compile the kernel

Under the root directory, enter:

#make uImage

It will take much time to complete the compiling. When completed, the compressed kernel image will be generated under linux-sunxi-sunxi-3.4.61_A20/arch/arm/boot directory.