目录分析
在OpenHarmony编译过程中，内核源码是不变的，内核源码保存在kernel/linux/linux-5.10/下，并且永远不被修改。
在编译内核前，会将内核源码复制到内核临时源码目录out/kernel/src_tmp/linux-5.10/下，然后再以打补丁的方式进行修改。
在编译命令./build.sh --product-name rk3568 --ccache中，用--product命令指定了rk3568。
通过查阅文档得知，这个product参数是在vendor文件夹中所指定的。
❯ vim vendor/hihope/rk3568/config.json
{
"product_name": "rk3568",
"device_company": "rockchip",
"device_build_path": "device/board/hihope/rk3568",
"target_cpu": "arm",
"type": "standard",
"version": "3.0",
"board": "rk3568",
...
}
|
在该配置文件中指定了product_name为rk3568的目标的编译路径是device/board/hihope/rk3568。
❯ cd device/board/hihope/rk3568
❯ ls
audio_drivers bootanimation BUILD.gn camera cfg config.gni device.gni distributedhardware kernel loader ohos.build startup updater wifi
|
目标的编译路径下面有很多文件，我们关心的是内核移植，所以只需要看kernel文件夹。
❯ cd kernel && ls
BUILD.gn build_kernel.sh dts JL201 logo.bmp logo_kernel.bmp ov8858.c
|
先从BUILD.gn文件开始看：
❯ cat BUILD.gn
···
import("//build/config/clang/clang.gni")
import("//build/ohos.gni")
kernel_build_script_dir = "//kernel/linux/linux-5.10"
kernel_source_dir = "//kernel/linux/linux-5.10"
action("kernel") {
script = "build_kernel.sh"
sources = [ kernel_source_dir ]
product_path = "vendor/$product_company/$product_name"
outputs = [ "$root_build_dir/../kernel/src_tmp/linux-5.10/boot_linux" ]
args = [
rebase_path(kernel_build_script_dir, root_build_dir),
rebase_path("$root_build_dir/packages/phone/images"),
rebase_path("//device/board/hihope/$device_name"),
product_path,
rebase_path("$root_build_dir/../.."),
device_company,
device_name,
product_company,
]
···
}
|
可以看到当构建流执行到这里的时候会直接执行build_kernel.sh这个脚本，并且传入一些参数。
编译流程
查看build_kernel.sh这个脚本：
set -e
pushd ${1}
ROOT_DIR=${5}
export PRODUCT_PATH=${4}
export DEVICE_COMPANY=${6}
export DEVICE_NAME=${7}
export PRODUCT_COMPANY=${8}
ENABLE_LTO_O0=${9}
KERNEL_SRC_TMP_PATH=${ROOT_DIR}/out/kernel/src_tmp/linux-5.10
KERNEL_OBJ_TMP_PATH=${ROOT_DIR}/out/kernel/OBJ/linux-5.10
KERNEL_SOURCE=${ROOT_DIR}/kernel/linux/linux-5.10
KERNEL_PATCH_PATH=${ROOT_DIR}/kernel/linux/patches/linux-5.10
KERNEL_PATCH=${ROOT_DIR}/kernel/linux/patches/linux-5.10/rk3568_patch/kernel.patch
KERNEL_CONFIG_FILE=${ROOT_DIR}/kernel/linux/config/linux-5.10/arch/arm64/configs/rk3568_standard_defconfig
NEWIP_PATCH_FILE=${ROOT_DIR}/foundation/communication/sfc/newip/apply_newip.sh
rm -rf ${KERNEL_SRC_TMP_PATH}
mkdir -p ${KERNEL_SRC_TMP_PATH}
rm -rf ${KERNEL_OBJ_TMP_PATH}
mkdir -p ${KERNEL_OBJ_TMP_PATH}
export KBUILD_OUTPUT=${KERNEL_OBJ_TMP_PATH}
cp -arf ${KERNEL_SOURCE}/* ${KERNEL_SRC_TMP_PATH}/
cd ${KERNEL_SRC_TMP_PATH}
bash ${ROOT_DIR}/drivers/hdf_core/adapter/khdf/linux/patch_hdf.sh ${ROOT_DIR} ${KERNEL_SRC_TMP_PATH} ${KERNEL_PATCH_PATH} ${DEVICE_NAME}
patch -p1 < ${KERNEL_PATCH}
if [ -f $NEWIP_PATCH_FILE ]; then
bash $NEWIP_PATCH_FILE ${ROOT_DIR} ${KERNEL_SRC_TMP_PATH} ${DEVICE_NAME} linux-5.10
fi
cp -rf ${3}/kernel/logo* ${KERNEL_SRC_TMP_PATH}/
cp -rf ${KERNEL_CONFIG_FILE} ${KERNEL_SRC_TMP_PATH}/arch/arm64/configs/rockchip_linux_defconfig
ramdisk_arg="disable_ramdisk"
make_ohos_env="GPUDRIVER=mali"
for i in "$@"
do
case $i in
enable_ramdisk)
ramdisk_arg=enable_ramdisk
;;
enable_mesa3d)
make_ohos_env="GPUDRIVER=mesa3d"
python ${ROOT_DIR}/third_party/mesa3d/ohos/modifyDtsi.py ${KERNEL_SRC_TMP_PATH}/arch/arm64/boot/dts/rockchip/rk3568.dtsi
;;
esac
done
eval $make_ohos_env ./make-ohos.sh TB-RK3568X0 $ramdisk_arg ${ENABLE_LTO_O0}
mkdir -p ${2}
if [ "enable_ramdisk" != "${10}" ]; then
cp ${KERNEL_OBJ_TMP_PATH}/boot_linux.img ${2}/boot_linux.img
fi
cp ${KERNEL_OBJ_TMP_PATH}/resource.img ${2}/resource.img
cp ${3}/loader/parameter.txt ${2}/parameter.txt
cp ${3}/loader/MiniLoaderAll.bin ${2}/MiniLoaderAll.bin
cp ${3}/loader/uboot.img ${2}/uboot.img
cp ${3}/loader/config.cfg ${2}/config.cfg
popd
../kernel/src_tmp/linux-5.10/make-boot.sh ..
|
变量解释
- KERNEL_SRC_TMP_PATH: 源码临时路径，在编译流程中，内核的原源码是不变的，需要将内核源码复制到这个路径下，然后对这个路径下的内核源码进行打补丁。
- KERNEL_OBJ_TMP_PATH: 目标临时路径。
- KERNEL_SOURCE: 内核原源码路径
- KERNEL_PATCH_PATH: 内核补丁路径
- KERNEL_PATCH: 内核补丁文件
- KERNEL_CONFIG_FILE: 内核配置文件
- NEWIP_PATCH_FILE: newip补丁文件
脚本解释
将内核源码复制到内核临时源码目录并且进入：
rm -rf ${KERNEL_SRC_TMP_PATH}
mkdir -p ${KERNEL_SRC_TMP_PATH}
rm -rf ${KERNEL_OBJ_TMP_PATH}
mkdir -p ${KERNEL_OBJ_TMP_PATH}
export KBUILD_OUTPUT=${KERNEL_OBJ_TMP_PATH}
cp -arf ${KERNEL_SOURCE}/* ${KERNEL_SRC_TMP_PATH}/
cd ${KERNEL_SRC_TMP_PATH}
|
对内核源码进行打补丁：
bash ${ROOT_DIR}/drivers/hdf_core/adapter/khdf/linux/patch_hdf.sh ${ROOT_DIR} ${KERNEL_SRC_TMP_PATH} ${KERNEL_PATCH_PATH} ${DEVICE_NAME}
patch -p1 < ${KERNEL_PATCH}
|
其中HDF的补丁调用到了drivers/hdf_core/adapter/khdf/linux/patch_hdf.sh这个脚本，脚本参数如下：
- OH工程根目录，绝对路径
- 内核临时目录，绝对路径
- 内核补丁路径，绝对路径
- 设备名称
patch_hdf.sh脚本对于补丁的搜索：
function put_hdf_patch()
{
HDF_PATCH_FILE=${KERNEL_PATCH_PATH}/${DEVICE_NAME}_patch/hdf.patch
if [ ! -e "${HDF_PATCH_FILE}" ]
then
HDF_PATCH_FILE=${KERNEL_PATCH_PATH}/${HDF_COMMON_PATCH}_patch/hdf.patch
fi
patch -p1 < $HDF_PATCH_FILE
}
|
可以看到此脚本是根据补丁路径+设备名称找到hdf.patch这个补丁。
拷贝开机logo和配置文件：
cp -rf ${3}/kernel/logo* ${KERNEL_SRC_TMP_PATH}/
cp -rf ${KERNEL_CONFIG_FILE} ${KERNEL_SRC_TMP_PATH}/arch/arm64/configs/rockchip_linux_defconfig
|
创建env和执行编译脚本：
ramdisk_arg="disable_ramdisk"
make_ohos_env="GPUDRIVER=mali"
for i in "$@"
do
case $i in
enable_ramdisk)
ramdisk_arg=enable_ramdisk
;;
enable_mesa3d)
make_ohos_env="GPUDRIVER=mesa3d"
python ${ROOT_DIR}/third_party/mesa3d/ohos/modifyDtsi.py ${KERNEL_SRC_TMP_PATH}/arch/arm64/boot/dts/rockchip/rk3568.dtsi
;;
esac
done
eval $make_ohos_env ./make-ohos.sh TB-RK3568X0 $ramdisk_arg ${ENABLE_LTO_O0}
|
make-ohos.sh脚本在内核临时源码目录，TB-RK3568X0是选择设备树的。
make-ohos.sh脚本中关于设备树如下：
···
model_list=(
"TB-RK3568X0 arm64 0xfe660000 rk3568-xxx Image rockchip_linux_defconfig"
)
···
|
其中TB-RK3568X0 是设备树目标名字， rk3568-xxx是具体的设备树名字，注意，没有后缀。
回到build_kernel.sh，创建编译文件目录并且拷贝过去：
mkdir -p ${2}
if [ "enable_ramdisk" != "${10}" ]; then
cp ${KERNEL_OBJ_TMP_PATH}/boot_linux.img ${2}/boot_linux.img
fi
cp ${KERNEL_OBJ_TMP_PATH}/resource.img ${2}/resource.img
cp ${3}/loader/parameter.txt ${2}/parameter.txt
cp ${3}/loader/MiniLoaderAll.bin ${2}/MiniLoaderAll.bin
cp ${3}/loader/uboot.img ${2}/uboot.img
cp ${3}/loader/config.cfg ${2}/config.cfg
popd
|
执行生成boot_linux.img脚本：
../kernel/src_tmp/linux-5.10/make-boot.sh ..
|
