Compiling the Kernel (NVIDIA DRIVE Linux)

This topic contains instructions for compiling the Linux Kernel source in your Linux SDK product.

Prerequisites

• You have unpacked the Kernel Source Code:

bash drive-t186ref-linux-*-oss-src.run

bash drive-t186ref-foundation-*-toolchain.run

This script creates this directory:

drive-oss-src

The top-level directory layout has this appearance:

hardware

toolchains

drive-oss-src

drive-t186ref-foundation

drive-t186ref-foundation_src

drive-t186ref-linux

drive-t186ref-linux_src

To compile the kernel

1. Set up the environment macros: The LOCAL_VERSION environment variable appends -tegra to the kernel version and modules.

export ARCH=arm64

export CROSS_COMPILE=<top>/toolchains/gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-

export LOCALVERSION="-tegra"

2. Set the kernel source directory as the current working directory:

cd <top>/drive-oss-src

3. Enter the following command to apply the rt-patches.

bash kernel/scripts/rt-patch.sh apply-patches

4. Create an output directory, and then configure the kernel for the board:

mkdir out-t186ref-linux

make -C kernel O=${PWD}/out-t186ref-linux clean

5. Add the following command:

make -C kernel O=${PWD}/out-t186ref-linux tegra_defconfig

6. Build the kernel:

make -j3 -C kernel O=${PWD}/out-t186ref-linux

Note:

If the above command fails, enter the make command without the j<number> option.

7. To flash the built images, copy the compressed (zImage) and uncompressed (Image) kernel images to the kernel top directory with the following commands:

cp ${PWD}/out-t186ref-linux/arch/arm64/boot/zImage <top>/drive-t186ref-linux/kernel-rt_patches

cp ${PWD}/out-t186ref-linux/arch/arm64/boot/Image <top>/drive-t186ref-linux/kernel-rt_patches

Caution: Before copying the new kernel images, create a backup of the default kernels provided.

8. Consolidate the built kernel modules in the build directory with the following commands:

export INSTALL_MOD_PATH=${PWD}/out-t186ref-linux

make -C kernel O=${PWD}/out-t186ref-linux modules_install

9. (Applies to: Ubuntu targetfs) Copy the built modules to the root filesystem path with the following commands:

sudo cp -a ${PWD}/out-t186ref-linux/lib/modules/* <top>/drive-t186ref-linux/targetfs/lib/modules

Note:

To ensure that all modules are loaded, at the target side, execute the commands:

depmod-a

sync

The sync command must be executed as superuser. From the next boot onward, the kernel modules are auto-loaded on boot.

10. If there is a change in the device tree source files, copy the newly generated DTB files:

cp <top>/drive-oss-src/out-t186ref-linux/arch/arm64/boot/dts/<dtb_file> <top>/drive-t186ref-linux/kernel