3. Build Buildroot firmware

This chapter introduces the compilation process of Buildroot firmware.

3.1. Build Linux-SDK

3.1.1. Precompile Configuration

There are configuration files for different board in device/rockchip/px30/, select the configuration file:

./build.sh px30-lvds-buildroot.mk

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

Configruation content:

# Target arch
export RK_ARCH=arm64                                            # 64-bit ARM
# Uboot defconfig
export RK_UBOOT_DEFCONFIG=evb-px30                              # u-boot configuration
# Kernel defconfig
export RK_KERNEL_DEFCONFIG=px30_linux_defconfig                 # kernel configuration
# Kernel dts
export RK_KERNEL_DTS=px30-firefly-lvds                          # dts file
# Buildroot config
export RK_CFG_BUILDROOT=rockchip_px30_64                        # Buildroot configuration
# Recovery config
export RK_CFG_RECOVERY=rockchip_px30_recovery                   # recovery configuration
# parameter for GPT table
export RK_PARAMETER=parameter.txt                               # partition table
# rootfs image path
export RK_ROOTFS_IMG=buildroot/output/$RK_CFG_BUILDROOT/images/rootfs.$RK_ROOTFS_TYP    # filesystem path

3.1.2. Partial compilation

  • u-boot

./build.sh uboot
  • kernel

./build.sh kernel
  • recovery

./build.sh recovery
  • Buildroot filesystem

Compile the Buildroot filesystem and generate the compiled output directory in buildroot/output:

./build.sh buildroot

3.1.3. Pack the firmware

Update each part of the .img link to the directory rockdev/:


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

./build.sh updateimg

3.1.4. Automatic compilation

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


3.2. Partition table

3.2.1. parameter

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

path: device/rockchip/px30/parameter.txt

MAGIC: 0x5041524B
ATAG: 0x00200800
PWR_HLD: 0,0,A,0,1
CMDLINE: mtdparts=rk29xxnand:0x00002000@0x00004000(uboot),0x00002000@0x00006000(trust),0x00002000@0x00008000(misc),0x00010000@0x0000a000(boot),0x00010000@0x0001a000(recovery),0x00010000@0x0002a000(backup),0x00020000@0x0003a000(oem),0x00c00000@0x0005a000(rootfs),-@0x00c5a000(userdata:grow)

The CMDLINE attribute is where we are concerned. Take uboot as an example. In 0x00002000@0x00004000(uboot), 0x00004000 is the starting position of the uboot partition, 0x00002000 is the size of the partition, and so on.

3.2.2. package-file

The package-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.

path: tools/linux/Linux_Pack_Firmware/rockdev/px30-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
boot            Image/boot.img
recovery        Image/recovery.img
rootfs          Image/rootfs.img
oem             Image/oem.img
userdata:grow   Image/userdata.img
backup          RESERVED