Compile the Buildroot firmware

This chapter introduces the compilation process of Buildroot firmware.
It is recommended to develop in the Ubuntu 16.04 system environment.
If you use other system versions, you may need to adjust the
compilation environment accordingly.

Download Firefly_Linux_SDK sub-volume compressed package

Since the Firefly_Linux_SDK source code package is relatively large,
some users' computers do not support files above 4G or the network
transmission of a single file is slow, so we use the method of sub-
volume compression to package the SDK. Users can obtain the
Firefly_Linux_SDK source code package in the following ways：

Firefly_Linux_SDK Source

Unpack Firefly_Linux_SDK sub-volume compressed package

The first time you use the SDK, you need to perform 3 steps. If you
want to update the SDK later, you only need to perform step 3 to
update the network.

   1. Unpack the SDK

   chmod +x ./sdk_tools.sh

   mkdir ../firefly_sdk

   Create a directory to store the SDK: For example, my current SDK is 3588, and I want to decompress it to the upper folder to avoid polluting the current directory

   mkdir ../firefly_rk3588_SDK
   ./sdk_tools.sh --unpack -C ../firefly_rk3588_SDK

   2. Restore the working directory

   Select the directory you just decompressed

   ./sdk_tools.sh --sync -C ../firefly_rk3588_SDK

   You can use the above script to execute or manually execute the command, choose one of them

   # Enter the directory just after decompression, for example, here is ../firefly_rk3588_SDK
   cd ../firefly_rk3588_SDK
   .repo/repo/repo sync -l
   .repo/repo/repo start firefly --all

   3. Update the SDK

   The first two steps are only performed when the SDK is decompressed for the first time, and the subsequent update of the SDK only needs to perform the third step for network update

   .repo/repo/repo sync -c --no-tags

Update Firefly_Linux_SDK

You can use the following command to update the SDK later

   .repo/repo/repo sync -c --no-tags

Directory Structure

   $ tree -L 1
   .
   ├── app
   ├── buildroot # Buildroot root file system build directory
   ├── build.sh -> device/rockchip/common/build.sh # compile script
   ├── debian # Debian root file system compilation directory
   ├── device # Compile related configuration files
   ├── distro
   ├── docs # Documentation
   ├── envsetup.sh -> buildroot/build/envsetup.sh
   ├── external
   ├── kernel
   ├── Makefile -> buildroot/build/Makefile
   ├── mkfirmware.sh -> device/rockchip/common/mkfirmware.sh # link script
   ├── prebuilts # Cross compilation tool chain
   ├── rkbin
   ├── rkflash.sh -> device/rockchip/common/rkflash.sh # Flash script
   ├── tools # Tools directory
   ├── u-boot
   └── yocto

Build a compilation environment

   sudo apt-get install expect-dev 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 expect

Compile SDK

Configuration before compilation

In the "device/rockchip/rk3399pro/" directory, there are configuration
files of different board types, select the configuration file:

   ./build.sh firefly-rk3399-buildroot.mk

The configuration file will be linked to
"device/rockchip/.BoardConfig.mk", check the file to verify whether
the configuration is successful.

Related configuration introduction:

   # Target arch
   export RK_ARCH=arm64 # 64-bit ARM architecture
   # Uboot defconfig
   export RK_UBOOT_DEFCONFIG=firefly-rk3399 # u-boot configuration file
   # Kernel defconfig
   export RK_KERNEL_DEFCONFIG=firefly3399pro_linux_defconfig # kernel configuration file
   # Kernel dts
   export RK_KERNEL_DTS=rk3399pro-firefly-aioc # dts file
   # Buildroot config
   export RK_CFG_BUILDROOT=rockchip_rk3399 # Buildroot configuration
   # Recovery config
   export RK_CFG_RECOVERY=rockchip_rk3399_recovery # recovery configuration
   # parameter for GPT table
   export RK_PARAMETER=parameter-buildroot.txt # Partition table
   # rootfs image path
   export RK_ROOTFS_IMG=buildroot/output/$RK_CFG_BUILDROOT/images/rootfs.$RK_ROOTFS_TYPE # root file system path

Partial compilation

Compile u-boot

   ./build.sh uboot

Compile kernel

   ./build.sh kernel

Compile recovery

   ./build.sh recovery

Compile Buildroot root file system

Compiling the Buildroot root file system will generate a compilation
output directory in "buildroot/output":

   ./build.sh buildroot

   # Note: Make sure to compile the Buildroot root file system as a normal user to avoid unnecessary errors.

Package the firmware

Update each part of the mirror link to the "rockdev/" directory:

   ./mkfirmware.sh

Pack the firmware, the generated complete firmware will be saved to
the "rockdev/pack/" directory.

   ./build.sh updateimg

Automatic compilation

Fully automatic compilation will perform the above compilation and
packaging operations to generate complete firmware.

   ./build.sh

Partition description

parameter partition table

The parameter.txt file contains the partition information of the
firmware. Take "parameter.txt" as an example:

Path: "device/rockchip/rk3288/parameter.txt"

   FIRMWARE_VER: 8.1
   MACHINE_MODEL: RK3399
   MACHINE_ID: 007
   MANUFACTURER: RK3399
   MAGIC: 0x5041524B
   ATAG: 0x00200800
   MACHINE: 3399
   CHECK_MASK: 0x80
   PWR_HLD: 0,0,A,0,1
   TYPE: GPT
   CMDLINE: mtdparts=rk29xxnand:0x00002000@0x00004000(uboot),0x00002000@0x00006000(trust),0x00002000@0x00008000(misc),0x00010000@0x0000a000(boot),0x00010000@0x0001a000(recovery),0x00010000x@0x0000@2a000) 0x0003a000(oem),0x00c00000@0x0005a000(rootfs),-@0x00c5a000(userdata:grow)
   uuid:rootfs=614e0000-0000-4b53-8000-1d28000054a9

The CMDLINE attribute is our focus. Taking uboot as an example,
0x00004000 in 0x00002000@0x00004000(uboot) is the starting position of
the uboot partition, 0x00002000 is the size of the partition, and so
on.

package-file

The package-file file is used to determine the required partition
image and image path when packaging the firmware, and it needs to be
consistent with the parameter.txt file.

Path: "tools/linux/Linux_Pack_Firmware/rockdev/rk3399-package-file"

   # NAME Relative path
   #
   #HWDEF HWDEF
   package-file package-file
   bootloader Image/MiniLoaderAll.bin
   parameter Image/parameter.txt
   trust Image/trust.img
   uboot Image/uboot.img
   misc Image/misc.img
   #resource Image/resource.img
   #kernel Image/kernel.img
   boot Image/boot.img
   recovery Image/recovery.img
   rootfs Image/rootfs.img
   oem Image/oem.img
   userdata:grow Image/userdata.img
   backup RESERVED
   #update-script update-script
   #recover-script recover-script