Senin, 25 Maret 2013

Compiling Rockchip Kernel (for Linux on RK devices)

Starting from Rockchip Linux' source code, along with several tools, we will end up with a recovery.img file. This is used to flash the recovery partition of an RK3066 device, which will then be able to boot into Ubuntu Linux.

WARNING: You DO NOT need to follow these steps unless you want to modify the kernel!

The stock kernel from Alok Sinha works fine and is very easy to install. Follow this guide:

https://www.miniand.com/wiki/Picuntu+Linux+Step+by+Step+Installation

Assuming the kernel is compiled from an x86 PC running an Ubuntu Linux:

#get the right packages for the compiler [3]
sudo apt-get install git-core gnupg flex bison gperf libsdl-dev libesd0-dev libwxgtk2.8-dev build-essential zip curl libncurses5-dev zlib1g-dev ia32-libs lib32z1-dev lib32ncurses5-dev gcc-multilib g++-multilib sharutils lzop

#start out from the user's home and create "rk" folder for all the work
cd ~
mkdir rk
cd rk

#toolchains folder is where the ARM compiler toolchain will be downloaded to [3]
git clone https://github.com/DooMLoRD/android_prebuilt_toolchains.git toolchains

#tools folder is where the mkbootimg tool (create recovery image) will be downloaded to [4]
git clone https://github.com/olegk0/tools.git

#initramfs folder is where the Picuntu kernel's .config file looks for initramfs.cpio (see CONFIG_INITRAMFS_SOURCE)
git clone https://github.com/Galland/rk30_linux_initramfs.git initramfs
cd initramfs
gzip -dc debian-3.0.8+fkubi.cpio.gz > initramfs.cpio
cd ..

~~#picuntu-3.0.8-alok is where we download the latest available Picuntu Linux kernel source code (0.9 RC3)~~
~~git clone https://github.com/aloksinha2001/picuntu-3.0.8-alok.git~~
~~cd picuntu-3.0.8-alok/~~

#rk3x_kernel_3.0.36 is where we download the latest available Picuntu Linux kernel source code
git clone https://github.com/Galland/rk3x_kernel_3.0.36.git
cd rk3x_kernel_3.0.36/

~~#copy Picuntu 0.9 RC3 config file (actually extracted from a running Picuntu, located at /proc/config.gz)~~

~~cp ../initramfs/config .config~~

#copy updated Picuntu kernel config file
cp config.galland .config

#set the target architecture and toolchain location (CHANGE the base folder if you are not using ~/rk/)
export ARCH=arm
export CROSS_COMPILE=~/rk/toolchains/arm-eabi-linaro-4.6.2/bin/arm-eabi-

#launch the Kernel compilation (-j 4 indicates that 4 compiler threads run in parallel, I have a quad-core PC...)
make -j 4

#
# Kernel compilation takes some minutes...
# BTW, don't worry about the warnings while compiling
#

#last step is to generate the recovery.img to flash the recovery partition of the Android stick
cd ..
tools/mkbootimg --kernel rk3x_kernel_3.0.36/arch/arm/boot/Image --ramdisk initramfs/fakeramdisk.gz --base 60400000 --pagesize 16384 --ramdiskaddr 62000000 -o recovery.img

Now flash recovery.img into the recovery partition and boot into Linux, just like using the stock kernel!

Installing modules and firmware

In the same x86 PC as above, after the flashing step:

mkdir mod_fw
cd rk3x_kernel_3.0.36
make modules_install INSTALL_MOD_PATH=~/rk/mod_fw/

A new folder called "lib", with "modules" and "firmware" subfolders, should appear inside "mod_fw". Copy & overwrite "lib" into the Picuntu MicroSD card's root folder, start Picuntu and in a Terminal write: