Build & Update Linux kernel on HiKey970
- Prepare Tools and Files
- Build the Linux kernel
  - Run build_kernel.sh

Build & Update Linux kernel on HiKey970

This page provides the instructions for building and deploying linux kernel on HiKey970 from x86 host machine.

NOTE: This instruction is to be used only after or during building AOSP

Prepare Tools and Files

Build Ramdisk
```
$ make -j$(nproc) ramdisk
```
Create Tools Folder
- Create a “tools” folder in the same level directory of the “linux” directory.
```
$ cd kernel
$ mkdir tools
```
Copy ramdisk.img and mkbootimg to the Tools Directory
- Copy the compiled ramdisk.img into the tools directory.
```
$ cp ../out/target/product/hikey970/ramdisk.img tools/
```

Modify the Compilation Script

Create the “build_kernel.sh” file, then copy the contents of the following text box and save it.

#!/bin/bash
DTB=1
LOCAL_DIR=$(pwd)
kernel_DIR=${LOCAL_DIR}/hikey-linaro/
PRODUCT_OUT=${LOCAL_DIR}/../out/target/product/hikey970/
GEN_IMAGES_DIR=${LOCAL_DIR}/tools
HIKEY970_kernel=${LOCAL_DIR}/tools
CURRENT_DIR=${LOCAL_DIR}
NCPU=`grep -c ^processor /proc/cpuinfo`
if [ ! -e ${PRODUCT_OUT} ]
then
mkdir -p ${PRODUCT_OUT}
fi
export MINI_SYS=true
export ARCH=arm64
check_build_result()
{
if [ $? != 0 ]; then
echo -e "\033[31m $1 build fail! \033[0m"
exit -1
else
echo -e "\033[32m $1 build success! \033[0m"
fi
}
if [ "${MINI_SYS}" != true ]; then
source ./build/envsetup.sh && lunch hikey970-userdebug && make
-j$[NCPU*2] $2
check_build_result "Android System"
fi
cd ${kernel_DIR}
make hikey970_defconfig && \
make -j$[NCPU*2] Image.gz modules
check_build_result "kernel Image"
rm -f arch/arm64/configs/hikey970_temp_defconfig
cp arch/arm64/boot/Image.gz ${HIKEY970_kernel}
if [ $DTB -eq 1 ]; then
make hisilicon/kirin970-hikey970.dtb
check_build_result "Hikey970 dtb"
cp arch/arm64/boot/dts/hisilicon/kirin970-hikey970.dtb ${HIKEY970_kernel}
fi
cd ${CURRENT_DIR}
if [ ${need_repack_userdata} ];
then
make -j$[NCPU*2] userdataimage-nodeps
check_build_result "Hikey970 need repack userdataimage"
fi
if [ "${MINI_SYS}" = true ]; then
RAMDISK=${GEN_IMAGES_DIR}/ramdisk.img
else
RAMDISK=${PRODUCT_OUT}/ramdisk.img
if  [ ! -e $RAMDISK ]; then
echo -e "\033[33m $RAMDISK is not exist! please build ramdisk first.
\033[0m"
echo -e "\033[33m . ./build/envsetup.sh && lunch hikey960-userdebug
&& make ramdisk \033[0m"
exit -1
fi
fi
#uefi boot.img = Image + dtb + ramdisk
cat ${kernel_DIR}/arch/arm64/boot/Image ${kernel_DIR}/arch/arm64/boot/dts/hisilicon/kirin970-hikey970.dtb > ${HIKEY970_kernel}/Image-dtb
check_build_result "Image-dtb"
mkbootimg --kernel ${HIKEY970_kernel}/Image-dtb --ramdisk ${RAMDISK} --cmdline "androidboot.hardware=hikey970 firmware_class.path=/system/etc/firmware loglevel=15 buildvariant=userdebug androidboot.selinux=permissive clk_ignore_unused=true" --base 0x0 --tags_offset 0x07A00000 --kernel_offset 0x00080000 --ramdisk_offset 0x07c00000 --output ${PRODUCT_OUT}/boot.img
check_build_result "Boot Image"
echo -e "\033[36m build boot.img complete! \033[0m"

Build the Linux kernel

Run build_kernel.sh

$ export ARCH=arm64
$ export CROSS_COMPILE=aarch64-linux-android-
$ ./build_kernel.sh

After the compilation is completed, the boot.img can be generated under “out/target/product/hikey970”.