Building Linux Kernel

This application note explains how to build Linux kernel images for the Emcraft STM32MP1 System-On-Module. Step through the following procedure:

1. Download the Yocto toolchain from the Emcraft website.

2. Install the toolchain to your development host. The toolchain can be installed to an arbitrary directory:

   $ sh ./meta-toolchain-qt5-openstlinux-weston-stm32mp15-som-x86_64-toolchain-4.2.1-snapshot.sh...

3. Activate the cross-build environment:

   $ source /opt/st/stm32mp15-som/4.2.1-snapshot/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi
   $ unset CCACHE_PATH

4. Clone the Emcraft Linux tree:

   $ mkdir build$ cd build
   $ git clone -b linux-stm32mp1-4.0.1  
   $ cd linux-stm32mp

5. Configure the kernel tree build:

   $ make multi_v7_defconfig

6. Build the kernel image:

   $ make -s -j10 uImage LOADADDR=0xC2000040
   ...
   $ ls -l arch/arm/boot/uImage

7. Build DTB (the device tree name is stm32mp157d-som.dtb for the 800MHz STM32MP1-SOM variant):

   $ make stm32mp157a-som.dtb
   $ ls -l arch/arm/boot/dts/stm32mp157a-som.dtb

8. Build kernel modules:

   $ make modules