Yocto/GettingStarted

Getting Started

This page is supposed to give a simple to follow guide of the first steps one have to do to assemble a setup for embedded development, preparing a first build via Yocto, build it and test-run it on the development device.

Material Needed

Embedded development always have the problem that you need some material additional to a development computer.

The most important components that one always should have:

• development board
• power supply for the development board
• micro SD card as main storage of the development board
• a micro SD card writer/reader
• a RS232-USB adapter for low level debugging of startup problems of the development board

Preparation for Yocto Build

Here we do a few things:

1. Prepare a Docker container with the required Yocto dependencies, in which the Yocto build will happen.
2. Checkout a configuration of the KDE Demo image and set it up

Preparation of Docker Container and Yocto Configurations

The basic source code repository for this step is kde:packaging/yocto-manifest (https://invent.kde.org/packaging/yocto-manifest). Select a location where you have a lot (and this really means >200 GB) of free space. In the following, we assume that /opt/yocto is such a location; just replace it in the commands if it is different.

# get Yocto sources
export YOCTODIR=/opt/yocto
git clone kde:packaging/yocto-manifest manifest

# step: prepare docker container with name "yocto-kirkstone"
docker build ${YOCTODIR}/manifest/containers/kirkstone  -t yocto-kirkstone

# step: obtain Google's repo tool
curl https://storage.googleapis.com/git-repo-downloads/repo > ${YOCTODIR}/repo
chmod a+x ${YOCTODIR}/repo

# step: prepare Yocto folder structure; using Yocto release "mickledore"
mkdir ${YOCTODIR}/mickledore && cd ${YOCTODIR}/mickledore
${YOCTODIR}/repo init -u https://invent.kde.org/packaging/yocto-manifest.git -m mickledore.xml
${YOCTODIR}/repo sync

Your First Yocto Build

In this step, we run the Docker container and inside it, we "source" the Bitbake environment. That means, by running the commands, we first enter the Docker container, which make it safe to not introduce unwanted environment variables and have all the tools needed. Secondly, the Bitbake compiling mode (called the "cooker" mode) essentially means that many environment variables are configured in your shell and we doing this by sourcing a script.

Please note that the call of the Docker container is created in a way that it mounts your host folder ${YOCTODIR} (which need to be set like in the previous step here) inside the Docker container, such that you can reuse data from one Yocto build to the next.

docker run -it --rm -v ${YOCTODIR}:/opt/yocto yocto-kirkstone
cd /opt/yocto/mickledore

# the MACHINE value decides which system is being built for, see below
MACHINE=raspberrypi4 . ./setup-environment
bitbake kde-demo-image --runall=fetch # first only fetch all the source code
bitbake kde-demo-image                # then start the build, which will take several hours

Available Images

With the default KDE configuration the following machine times are available and are recommended:

• raspberrypi4
• visionfive2
• raspberrypi3