Buildroot based Raspberry Pi 3 / RPI3 example for OP-TEE
Based on buildroot 2024.02.2, last updated 2024.06.09
TF: v2.10, OP-TEE: 4.0.0
Need to use u-boot 2021.07 due to FIT signature verification issues found in 2022.04 Need to use kernel 967d45b29ca2902f031b867809d72e3b3d623e7a (5.10.1-v8, from 2021.07) due to SD-Card driver issues
You must clone this project with
git clone --recursive https://github.com/schenkmi/buildroot-rpi-optee.git
You can build the image with
cd buildroot-rpi-optee
mkdir -p out && cd out
make -C ../buildroot O="$(pwd)" BR2_EXTERNAL="../buildroot-external" rpi3_defconfig
make
The first step is to build the Docker image and create a container. You can specify a directory in your hosts system which will be mounted inside the container. This allows you to copy the built system easily. The current directory must contain the provided Dockerfile which will be compiled into an image. The directory called build will contain the sources and the images which will be built later.
mkdir -p build
docker build -t br-optee-rpi .
docker create -it --name br-optee-rpi --mount type=bind,source="$(pwd)",destination=/build br-optee-rpi
You can start the container if it was created successfully. This command gives you an interactive shell inside the container.
docker start -ia br-optee-rpi
The next step is to create a build directory called out which will contain the downloaded package source files and the output images. We will use this directory for an out-of-tree Buildroot build, by adding the O= parameter to the make command. We have to specify the directories where the external trees are stored, which can be done by adding the BR2_EXTERNAL= parameter to make (We can specify multiple directories by using : as a separator). The default config file is called rpi3_defconfig which is inside the configs directory.
mkdir -p out && cd out
make -C ../buildroot O="$(pwd)" BR2_EXTERNAL="../buildroot-external" rpi3_defconfig
After the configuration has been finalized you can issue the make command to start building the sources. This can take a long time, so be patient.
make
Precondition: you are inside out/ folder
make -C ../buildroot O="$(pwd)" BR2_EXTERNAL="../buildroot-external" menuconfig
make -C ../buildroot O="$(pwd)" BR2_EXTERNAL="../buildroot-external" update-defconfig
make -C ../buildroot O="$(pwd)" BR2_EXTERNAL="../buildroot-external" sdk
Please change /dev/sdX with the correct mounting point of your sd card.
sudo umount /dev/sdX?*
sudo dd if=images/sdcard.img of=/dev/sdX bs=1M conv=fdatasync status=progress
sudo picocom -b 115200 /dev/ttyUSB0
git tag -a V1.5.0 -m "update to buildroot 2024.02.2, TF v2.10, OP_TEE 4.0.0"
git push --tags
cd buildroot-external/board/rpi3
mkdir keys
openssl genrsa -F4 -out "keys/dev.key" 4096
openssl req -batch -new -x509 -key "keys/dev.key" -out "keys/dev.crt"
This step needs to be done for every updated U-BOOT to have the DTB in sync with U-BOOT.
cd out/images
cp ../build/uboot-2021.01/arch/arm/dts/bcm2837-rpi-3-b.dtb u-boot-bcm2837-rpi-3-b.dtb
The mkimage will place the public key into the DTB. This DTB will be used to build the U-BOOT.
cd out/images
cp -R ../../buildroot-external/board/rpi3/keys .
cp ../../buildroot-external/board/rpi3/rpi3_bcm2837_fit.its .
cp ../build/uboot-2021.07/arch/arm/dts/bcm2837-rpi-3-b.dtb u-boot-bcm2837-rpi-3-b.dtb
PATH=../host/bin:$PATH mkimage -f rpi3_bcm2837_fit.its -K u-boot-bcm2837-rpi-3-b.dtb -k ./keys -r image.fit
cp u-boot-bcm2837-rpi-3-b.dtb ../../buildroot-external/board/rpi3/
cd out
make menuconfig
U-BOOT Options
(EXT_DTB=${BR2_EXTERNAL_RPI_OPTEE_PATH}/board/rpi3/u-boot-bcm2837-rpi-3-b.dtb) Custom make options
OP-TEE can be tested with the xtest application
xtest
git remote add ssh git@github.com:schenkmi/buildroot-rpi-optee.git
To re-build u-boot we need to build u-boot and arm-trusted-firmware
cd out
rm -rf build/uboot-2021.07/
rm -rf build/arm-trusted-firmware-v2.10/
make