Buildroot

1 Introduction to Buildroot

Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. It contains a boot-loader, kernel, rootfs, various libraries and utilities(e.g. qt, gstreamer, busybox etc).

FriendlyELEC's Buildroot is based on Rockchip's version which is made with linux-sdk and maintained with git. FriendlyELEC's version is synced with Rockchip's version;

Rockchip's Buildroot: https://github.com/rockchip-linux/buildroot
Buildroot's official site: https://buildroot.org

2 Download Images of Trial Version

Visit Download LinkDownload:

Image Files
rk3399-sd-buildroot-linux-4.4-arm64-YYYYMMDD.img.zip	OS image booting from SD card
rk3399-eflasher-buildroot-YYYYMMDD.img.zip	Image used to flash to eMMC

After extract the file you can use either dd or the win32image utility to flash the image to an SD card.

3 User Name and Password

User name: root
Password: rockchip

4 Obtain Source Code

4.1 Install repo Utility

Install the repo utility:

git clone https://github.com/friendlyarm/repo
cp repo/repo /usr/bin/

4.2 Download Source Code

You can retrieve a project's source code in either of the following two ways. The first works better with Mainland Chinese users:

4.2.1 1: Retrieve Repo Package from Cloud Storage

Download link: Click to enter
File location: sources/linuxsdk-friendlyelec-YYYYMMDD.tar (YYYYMMDD stands for the data when the package is generated)
After you get a tar package, untar it and run the following command to extract it:

tar xvf /path/to/netdisk/sources/linuxsdk-friendlyelec-YYYYMMDD.tar
cd linuxsdk-friendlyelec
repo sync -l

If you want to get the latest official source code you can run the following commands:

cd linuxsdk-friendlyelec
repo sync

4.2.2 2: Retrive Repo Package from Github

mkdir linuxsdk-friendlyelec
cd linuxsdk-friendlyelec
repo init -u https://github.com/friendlyarm/buildroot_manifests -b master -m rk3399_linux_release.xml --repo-url=https://github.com/rockchip-linux/repo
repo sync -c

4.2.3 Get Latest Version with Sync

cd linuxsdk-friendlyelec
repo sync -c

If your network connection is broken during sync you can run the following script to do it:

#! /bin/bash
repo sync -c
while [ $? -ne 0 ]; 
do  
    repo sync -c
done

5 如何编译

5.1 搭建编译环境

在PC的Ubuntu系统下，执下以下命令安装所需的软件：

sudo apt-get install repo git-core gitk git-gui gcc-arm-linux-gnueabihf u-boot-tools device-tree-
compiler gcc-aarch64-linux-gnu mtools parted libudev-dev libusb-1.0-0-dev python-linaro-image-
tools linaro-image-tools autoconf autotools-dev libsigsegv2 m4 intltool libdrm-dev curl sed make
binutils build-essential gcc g++ bash patch gzip bzip2 perl tar cpio python unzip rsync file bc wget
libncurses5 libqt4-dev libglib2.0-dev libgtk2.0-dev libglade2-dev cvs git mercurial rsync openssh-
client subversion asciidoc w3m dblatex graphviz python-matplotlib libc6:i386 libssl-dev texinfo
liblz4-tool genext2fs lib32stdc++6

5.2 全自动方式编译

./build.sh

5.3 部分编译

5.3.1 kernel

./build.sh kernel

5.3.2 u-boot

./build.sh uboot

5.3.3 rootfs

./build.sh rootfs

5.4 生成sdcard固件

sudo ./build.sh sd-img

或者直接将固件烧写到sd卡:

./friendlyelec/rk3399/sd-fuse_rk3399/fusing.sh /dev/sdX buildroot

其中，/dev/sdX请替换为真实的SD卡设备文件名。

5.5 生成emmc (eflasher) 固件

sudo ./build.sh emmc-img

5.6 查看帮助

# ./build.sh help
====USAGE: build.sh modules====
uboot              -build uboot
kernel             -build kernel
rootfs             -build default rootfs, currently build buildroot as default
buildroot          -build buildroot rootfs
ramboot            -build ramboot image
yocto              -build yocto rootfs, currently build ros as default
ros                -build ros rootfs
debian             -build debian rootfs
pcba               -build pcba
recovery           -build recovery
all                -build uboot, kernel, rootfs, recovery image
cleanall           -clean uboot, kernel, rootfs, recovery
firmware           -pack all the image we need to boot up system
updateimg          -pack update image
sd-img             -pack sd-card image, used to create bootable SD card
emmc-img           -pack sd-card image, used to install buildroot to emmc
save               -save images, patches, commands used to debug
default            -build all module

重点参数说明：
uboot -单独编译uboot
kernel -单独编译kernel
rootfs -单独编译buildroot
buildroot -同上
sdimg -生成用于dd到sd卡的image文件，以及用于eFlasher工具使用的eMMC烧写文件

6 Buildroot定制与开发

6.1 目录结构

├── linuxsdk-friendlyelec
│   ├── app
│   ├── buildroot buildroot根文件系统的编译目录
│   ├── build.sh -> device/rockchip/common/build.sh 全自动编译脚本
│   ├── device 编译相关配置文件
│   ├── distro debian根文件系统生成目录
│   ├── docs 文档
│   ├── envsetup.sh -> buildroot/build/envsetup.sh
│   ├── external
│   ├── friendlyelec 用于适配友善电子RK3399开发板的文件
│   ├── kernel 内核
│   ├── Makefile -> buildroot/build/Makefile
│   ├── mkfirmware.sh -> device/rockchip/common/mkfirmware.sh rockdev链接更新脚本
│   ├── prebuilts
│   ├── rkbin 
│   ├── rkflash.sh -> device/rockchip/common/rkflash.sh 烧写脚本
│   ├── rootfs debian根文件系统编译目录
│   ├── tools 烧写、打包工具
│   └── u-boot u-boot

6.1.1 更改Buildroot配置

列出当前可用的配置

cd buildroot
make list-defconfigs

显示所下：
rockchip_rk3399_defconfig - Build for rockchip_rk3399

使用menuconfig更改配置

make rockchip_rk3399_defconfig
make menuconfig
make savedefconfig
diff .defconfig configs/rockchip_rk3399_defconfig 
cp .defconfig configs/rockchip_rk3399_defconfig

重新编译

cd ../
./build.sh rootfs

6.2 预装文件到文件系统

将文件放在 friendlyelec/rk3399/fs-overlay-64，然后重新编译 rootfs。

6.3 修改u-boot和kernel

直接修改u-boot和kernel目录下的文件即可。

6.4 使用sdk里的交叉编译器

export PATH=$PWD/buildroot/output/rockchip_rk3399/host/bin/:$PATH
aarch64-buildroot-linux-gnu-g++ -v

显示版本如下：
gcc 版本 6.4.0 (Buildroot 2018.02-rc3-g4f000a0797)

6.5 交叉编译Qt程序

git clone https://github.com/friendlyarm/QtE-Demo.git
cd QtE-Demo
../buildroot/output/rockchip_rk3399/host/bin/qmake QtE-Demo.pro
make

要实现开机自动运行你的Qt程序，可将QtE-Demo拷贝到开发板上，然后修改 /etc/init.d/下的S50launcher，将/usr/local/QLauncher/QLauncher &这一行改为QtE-Demo的文件路径即可。

7 常见问题

7.1 如何获取用于USB Type-C烧写的文件?

执行 build.sh emmc-img 之后，在 friendlyelec/rk3399/sd-fuse_rk3399 下面会有一个 buildroot 目录，使用android_tools工具加载这个目录下的文件即可。