Difference between revisions of "Rock/Booting Linux"

Revision as of 02:24, 5 December 2014

Requirement

• a radxa rock board (check your hardware revision)
• a desktop/laptop running Linux(64bit preferred)
• a micro usb cable, one side plugged in to the OTG port of radxa rock, the other side plugged in to the usb port on desktop/laptop

Prepare the build environment

Install the packages

Install packages for building kernel if you don't have them on your host.

   sudo apt-get install build-essential lzop libncurses5-dev libssl-dev

Install the toolchain

Download ARM toolchain if you don't have Android 4.2.2/4.4.2 SDK on your host.

if your host is 64bit

   git clone -b kitkat-release --depth 1 https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6

if your host is 32bit

   git clone -b jb-release --depth 1 https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6

then set environment variables

   export ARCH=arm
   export CROSS_COMPILE=`pwd`/arm-eabi-4.6/bin/arm-eabi-

you can use any toolchain if you are sure it works, or you can fix any error introduced by toolchain.

Get the source code

   git clone -b radxa-stable-3.0 https://github.com/radxa/linux-rockchip.git

Build the kernel

   cd linux-rockchip

if your Rock is pro(Mid 2014) or the new lite(Mid 2014), use radxa_rock_pro_linux_defconfig, check out hardware revision

   make radxa_rock_pro_linux_defconfig

if your rock is full version(2013) or engineering sample or the old lite(2013), use radxa_rock_linux_defconfig, check out hardware revision

   make radxa_rock_linux_defconfig

   make -j8 kernel.img

The kernel will be at kernel.img (image for kernel partition) and arch/arm/boot/Image (raw binary)

if you want LZO compressed kernel, specify zkernel.img

   make -j8 zkernel.img

The kernel will be at kernel.img (image for kernel partition) and arch/arm/boot/zImage (compressed binary)

Build the kernel modules

   mkdir modules
   make INSTALL_MOD_PATH=./modules modules modules_install

Now you have kernel modules in modules/lib/modules/ and firmwares for some devices in modules/lib/firmware/.

Generate the image

Generate the initramfs

   cd ..
   git clone https://github.com/radxa/initrd.git
   make -C initrd

Generate the boot.img

Install mkbootimg

   git clone https://github.com/neo-technologies/rockchip-mkbootimg.git
   cd rockchip-mkbootimg
   make
   sudo make install
   cd ..

Make boot.img

   mkbootimg --kernel linux-rockchip/arch/arm/boot/Image --ramdisk initrd.img -o boot.img

Done. Now we have the boot.img (image for boot/recovery partition) for RR.

Modify the parameter

The linux rootfs can be put on the different partition or media(nand or uSD card or USB disk), so you need to tell the kernel which is the right rootfs to mount. So change the root= command line in your parameter to the rootfs you want to mount. The examples are:

   root=/dev/block/mtd/by-name/linuxroot        # rootfs in the nand partition named "linuxroot"
   root=/dev/mmcblk0p1          # rootfs in the uSD card first partition
   root=/dev/sda1                # rootfs in the U disk or the USB hard drive first partition
   root=LABEL=linuxroot         # rootfs in the partition with label "linuxroot", can be in uSD, U disk or USB hard drive.

Next step

Now you refer flash the image to flash the generated boot.img to "boot" partition parameter to "parameter" partition of your radxa rock board. And download a prebuilt rootfs or make your own rootfs. You will get linux system boot into ramdisk and then switch root to real rootfs.