Configuring U-Boot and Kernel Option Parameters

In system software development, it is often necessary to configure the functional options of u-boot and the kernel. This chapter introduces several commonly used configuration methods for users' reference.

Configuring U-Boot Option Parameters

Note

​ The following instructions use the modification of the hobot_s100_defconfig configuration file as an example.

​ The specific configuration file used by U-Boot can be found by checking the value of the HR_UBOOT_CONFIG_FILE variable in the board-level configuration file bootloader/device/.board_config.mk after running ./xbuild.sh lunch.

Configuring via the xbuild Command

First, navigate to the source/bootloader directory. The directory structure is as follows:

├── build # Compilation system code directory, provides shell scripts for compiling various functional modules, and tools used for compilation
├── device # Board-level configuration directory, each hardware has its own configuration file, where compilation options and partition tables can be set
├── miniboot # Generates a minimal boot firmware that includes gpt, mbr, bl2, ddr, bl3x
├── out # Compilation output directory
└── uboot # U-Boot source code

build/xbuild.sh is the main compilation script and provides the following command to help users configure U-Boot options. This command automatically uses the U-Boot configuration file set in the board-level configuration file, and after configuration, automatically completes savedefconfig and saves the work.

./xbuild.sh uboot menuconfig

After the command executes successfully, the U-Boot graphical configuration interface will open. You can configure options in this interactive interface, including removing unnecessary features and enabling required ones.

After completing the configuration on the menuconfig interface, select Exit to quit, and choose Yes or No according to the prompts to save the changes to the .config file.

After exiting the configuration, the configuration file will be automatically saved. The automatic process includes:

# Call savedefconfig to clean the configuration file, retain necessary items, remove dependencies, and generate a defconfig file
make savedefconfig
# Overwrite the U-Boot configuration file set in the board-level configuration file with the defconfig file
cp -f defconfig <U-Boot configuration file set in the board-level configuration file>

Manual Configuration

First, navigate to the source/bootloader/uboot directory and execute make ARCH=arm64 hobot_s100_defconfig. The make command will first execute the Makefile in the top-level directory. For targets ending with config, there is a common entry point:

%config: scripts_basic outputmakefile FORCE
        $(Q)$(MAKE) $(build)=scripts/kconfig $@

The expanded execution command is:

make -f ./scripts/Makefile.build obj=scripts/kconfig hobot_s100_defconfig

After executing this command, a .config file will be generated in the root directory of the U-Boot source code.

make ARCH=arm64 hobot_s100_defconfig

  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  YACC    scripts/kconfig/zconf.tab.c
  LEX     scripts/kconfig/zconf.lex.c
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
#
# configuration written to .config
#

Then, execute make ARCH=arm64 menuconfig to open the graphical configuration interface and configure U-Boot option parameters.

After completing the configuration on the menuconfig interface, select Exit to quit, and choose Yes or No according to the prompts to save the changes to the .config file.

After saving the configuration, you can run the command diff .config configs/hobot_s100_defconfig to compare the differences and confirm that the changes meet your expectations.

If the modifications are correct, execute cp .config configs/hobot_s100_defconfig to replace the default configuration file.

Clean up files like .config in the source directory; otherwise, when recompiling the system, you will be prompted that "xxx is not clean, please run 'make mrproper'".

make distclean
# or
make mrproper

Configuring Kernel Option Parameters

Note

​ The following instructions use the modification of the drobot_s100_defconfig configuration file as an example.

​ The specific configuration file used by the kernel can be found by checking the value of the kernel_config_file variable in the mk_kernel.sh script.

Configuring via the mk_kernel Command

mk_kernel.sh provides the following command to help users configure Kernel options. This command automatically uses the Kernel configuration file set in the board-level configuration file, and after configuration, automatically completes savedefconfig and saves the work.

./mk_kernel.sh menuconfig

After the command executes successfully, the Kernel graphical configuration interface will open. You can configure options in this interactive interface, including removing unnecessary features and enabling required ones.

After completing the configuration on the menuconfig interface, select Exit to quit, and choose Yes or No according to the prompts to save the changes to the .config file.

After exiting the configuration, the configuration file will be automatically saved. The automatic process includes:

# Call savedefconfig to clean the configuration file, retain necessary items, remove dependencies, and generate a defconfig file
make savedefconfig
# Overwrite the Kernel configuration file set in the board-level configuration file with the defconfig file
cp defconfig <Kernel configuration file set in the board-level configuration file>

Manual Configuration

Configuring the kernel via menuconfig follows a similar process to configuring U-Boot. The command execution process is as follows:

First, navigate to the source/kernel directory, then follow these steps to configure kernel options.

• Use drobot_s100_defconfig to generate .config. If a full compilation of the source code has been performed, the .config file will already be configured.

make ARCH=arm64 drobot_s100_defconfig

• Execute the following command to modify the configuration:

make ARCH=arm64 menuconfig

• After modification, you can check the differences between the modified and unmodified versions:

diff .config hobot-drivers/configs/drobot_s100_defconfig

• Overwrite drobot_s100_defconfig with the new configuration:

cp .config hobot-drivers/configs/drobot_s100_defconfig

• Clean up files like .config in the source directory; otherwise, when recompiling the system, you will be prompted that "xxx is not clean, please run 'make mrproper'".

make distclean
# or
make mrproper