Build Vicharak Kernel from source

Vicharak provides multiple revisions of Linux kernels for Vaaman board. These revisions incorporate bug fixes, upstream improvements, and specific optimizations for Vaaman.

Types of kernels available for Vaaman

Vicharak offers four versions of the Linux kernel for the Vaaman board, with each version based on a higher iteration of the Linux kernel.

These kernel revisions are based on the sources of Rockchip RK3399 SoC with necessary changes and optimizations for Vaaman. Take a look at the following table for the available kernels.

Kernel version	Status	Git Link
Kernel 4.4	Stable but deprecated	https://github.com/vicharak-in/rockchip-linux-kernel/tree/vaaman-4.4
Kernel 4.19	Stable but deprecated	https://github.com/vicharak-in/rockchip-linux-kernel/tree/vaaman-4.19
Kernel 5.10	Stable (Recommended)	https://github.com/vicharak-in/rockchip-linux-kernel/tree/master
Kernel Mainline	Experimental	https://github.com/vicharak-in/rockchip-linux-kernel/tree/vicharak-mainline

Warning

Some of the kernel versions might not contain all the features supported or required by Vaaman. Please take a look at the Vaaman Kernel Status table for the status of the different kernels available for Vaaman.

Build Linux Kernel

Installing the system dependencies

To build the Linux kernel successfully, your system needs certain dependencies. These tools and libraries are essential for compiling, linking, and generating the necessary files to create a functional kernel for your Vaaman board.

Ensure that your system has the following dependencies installed…

Warning

It is recommended to use Ubuntu 20.04 and Higher or Debian 11 and Higher environment for building.

sudo apt-get update

sudo apt-get install build-essential python3 python-is-python3 libssl-dev \
git-core gcc-arm-linux-gnueabihf u-boot-tools device-tree-compiler \
gcc-aarch64-linux-gnu mtools parted pv bc bison flex gawk

Getting the kernel source

You can obtain the kernel source either by cloning the repository using Git, allowing easy updates, or by downloading it as an archive, providing a snapshot of the source code at a specific point in time.

Download the kernel source from Vicharak’s GitHub

Using Git Clone

git clone https://github.com/vicharak-in/rockchip-linux-kernel -b master

Using Web browser

vicharak-linux-kernel-github

Follow the steps in above image.

Open the GitHub page and click on the < > Code button.
Select the “Download ZIP” option.
After successful download, unpack the archive using any archiver tool (7zip, unzip, etc).

Using Terminal

wget https://github.com/vicharak-in/linux-kernel/archive/refs/heads/master.zip

unzip master.zip
mv linux-kernel-master linux-kernel

Compiling the Linux kernel

Enter the kernel directory

cd linux-kernel

Compile Rockchip Linux config

Before compiling the Linux kernel, it’s crucial to set up the Rockchip Linux config. This configuration specifies the parameters required for the Linux kernel to run on the Rockchip RK3399 SoC, ensuring compatibility with your Vaaman board.

export CROSS_COMPILE=aarch64-linux-gnu-

make O=out ARCH=arm64 rockchip_linux_defconfig

Tip

You can also use custom toolchain for compilation.

Clone your custom toolchain from the internet.
Export LD_LIBRARY_PATH and PATH variables

export LD_LIBRARY_PATH=<path-to-custom-toolchain>/lib:$LD_LIBRARY_PATH
export PATH=<path-to-custom-toolchain>/bin:$PATH

Build the kernel using the normal steps

Copy Vaaman specific configs to .config

To customize the kernel for Vaaman, it’s essential to merge Vaaman-specific configurations into the existing .config file. This ensures that the kernel is tailored to the hardware specifications of your Vaaman board.

./scripts/kconfig/merge_config.sh -m out/.config arch/arm64/configs/rk3399_vaaman.config

cat arch/arm64/configs/rk3399_vaaman.config >> out/.config

Warning

When using Vaaman kernel version 4.4, please note that the file arch/arm64/configs/rk3399_vaaman.config will not be available.

Consequently, you should refrain from using the provided commands to merge Vaaman-specific configurations into the .config file.

Finally compile the kernel

make O=out ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc --all)

Upon successful compilation, confirm that you have following files.

out/arch/arm64/boot/dts/rockchip/rk3399-vaaman-linux.dtb
out/arch/arm64/boot/Image

Warning

On Vaaman kernel version 4.4 you will not have out/arch/arm64/boot/dts/rockchip/rk3399-vaaman-linux.dtb. Instead you might find rk3399-vaaman.dtb which is perfectly fine to use.

Vicharak’s Kernel build script

Vicharak’s Kernel build script simplifies the compilation process and ensures that your kernel is built with the correct configurations.

Enabling support for this script using the provided command allows for effortless updates to the kernel source and smoother integration with Vicharak’s development environment.

git submodule update --init

Reference

More information on Vicharak kernel building script.

Compiling Kernel Modules

In addition to compiling the Linux kernel, you can also build kernel modules. These modules are pieces of code that can be loaded and unloaded into the kernel as needed, allowing you to add or remove specific functionalities without recompiling the entire kernel.

This section guides you through the process of compiling and installing these modules for your Vaaman board.

make O=out ARCH=arm64 modules_install INSTALL_MOD_PATH=modules -j$(nproc --all)

Confirm the modules files in out/modules/lib folder

Tip

Set the specific driver that you want to build as module to CONFIG_<XXXX>=m inside .config

How to flash compiled Linux Kernel

Copy images to boot partition

Copy the compiled kernel images to the device

scp out/arch/arm64/boot/Image <user>@<device-ip>:~/
scp out/arch/arm64/boot/dts/rockchip/rk3399-vaaman-linux.dtb <user>@<device-ip>:~/
scp -r out/arch/arm64/boot/dts/rockchip/overlays <user>@<device-ip>:~/
scp out/modules_rk3399_vaaman.tar.gz <user>@<device-ip>:~/

Tip

Replace user with the appropriate username for Vaaman and device-ip with the actual IP address of your board.

You can find your username using whoami command and, hostname using cat /etc/hostname

Flash the kernel image

ssh login into the device or open the terminal on the device running linux system and run the following commands

sudo rm -rf /boot/Image
sudo rm -rf /boot/rk3399-vaaman-linux.dtb
sudo rm -rf /boot/overlays
sudo cp Image /boot/Image
sudo cp rk3399-vaaman-linux.dtb /boot/rk3399-vaaman-linux.dtb
sudo cp -r overlays /boot

Copy modules to the device

sudo tar -xvf modules_rk3399_vaaman.tar.gz -C /

Reboot the device

sudo reboot

Installing as a debian package

Note

You can also install the linux kernel as a debian package

Vicharak has created a custom debian package configuration for building a fully functional debian package for the linux kernel.

Assuming that you have compiled the kernel as a debian package, you can install it using the following command.

sudo apt install linux-image-rk3399-vaaman-XXXXXX.deb

After successful installation you can safely reboot your board.

Reboot the device

sudo reboot

Flashing using dd tool

You can also flash the boot image using the following commands

Assuming that you have compiled the kernel using the Vicharak kernel building scripts as it will generate a boot image in the out/ folder. You can install it using the following command.

sudo dd if=boot.img of=/dev/mmcblkXp4 status=progress; sync

Note

Here mmcblkXp4 is the boot partition of the device. Replace X with the device number

SD-card
eMMC

See also

For flashing the boot image using Rockchip upgrade tool refer to Rockchip Linux Upgrade Tool

See also

How to compile u-boot from source

How to flash u-boot

U-Boot (Universal Boot Loader)

Linux SDK