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Version: 5.0

Build TorizonCore from Source With Yocto Project/OpenEmbedded

Introduction​

TorizonCore is the base operating system in which Torizon is built. It is a minimal Yocto-based embedded Linux image and, even though customers may usually stick to application development on top of containers, sometimes they may need to customize the base image for their needs.

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If you just want to start using TorizonCore as-is with no customization in the original image, see the Quickstart Guide for information on how to install it on your Toradex Computer-on-Module.

Before trying to build TorizonCore using Yocto Project/Open Embedded, briefly read what TorizonCore Builder can do. It's a Toradex-provided tool that can help in customizing your TorizonCore image, without having to deal with Yocto.

The Toradex manifest repository contains a Repo manifest and setup scripts for the TorizonCore build system. If you want to modify, extend or port TorizonCore to a new hardware platform, this is the manifest repository to use.

The build system uses various components from the Yocto Project, most importantly the OpenEmbedded build system, the bitbake task executor and various application and BSP layers.

You have two options to build TorizonCore (and possibly any Yocto-based image):

  • Use a native distribution like Ubuntu to build TorizonCore.
    • Pros: has the advantage that you can easily understand what is going on.
    • Cons: you may be stuck on a certain Distribution Version which is supported by the Yocto Release where TorizonCore is built on; you need to install all dependencies by yourself in every new development machine.
  • Use a Docker container and build everything inside that container.
    • Pros: it has the advantage that it will work independently of the version of the host distribution; it works under Windows; the commands used inside the container are the exact same as if you would build on the native distribution.
    • Cons: it may seem to be more complicated at the first look.

You can build TorizonCore natively under your favorite Linux flavor. However, not all distribution version/Yocto version combos are allowed. If your distribution is not supported you will get a warning when running your first bitbake command. In such cases, it may happen that your current distribution can't build TorizonCore. You may consider trying to use a Docker container then.

This article complies to the Typographic Conventions for Torizon Documentation.

Common Prerequisites​

The following information is something that you should determine before proceeding with either build option.

Manifest Branch​

The manifest branch refers to the git branch of the manifest repository that will be used for setup. The available branches related to TorizonCore images are:

TorizonCore versionBranch
5.x.ydunfell-5.x.y
0.0.0master

These branches come from the official Toradex Manifest Repository.

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master is maintained to monitor changes in the external layers. Builds can be broken for a longer period of time. This branch is not recommended for productization.

Manifest File​

The manifest file refers to the specific file in the manifest repository that will be used for setup. The available files related to Torizon images are:

  • torizoncore/default.xml
  • torizoncore/integration.xml
  • torizoncore/next.xml

It is recommended to use torizoncore/default.xml. The other two manifest files are used by Toradex to monitor future changes and may not be stable.

TorizonCore Distro​

Within the greater Torizon platform, Toradex provides different variations of TorizonCore. In the OpenEmbedded community these are known as "Distros". For TorizonCore, Toradex provides the following Distros:

DistroKernel BaseKernel Config
torizonDownstream kernel from SoC vendor (NXP) (default for iMX8* based modules)Default (without the PREEMPT_RT patch)
torizon-upstreamMainline kernel (default for iMX6/iMX7 based modules)Default (without the PREEMPT_RT patch)
torizon-rtDownstream kernel from SoC vendor (NXP)Fully preemptive (real-time Linux PREEMPT_RT patch)
torizon-upstream-rtMainline kernelFully preemptive (real-time Linux PREEMPT_RT patch)

Machine​

Supported MACHINE targets (officially tested by Toradex):

Machine NameCorresponding Toradex Module
apalis-imx6Apalis iMX6
apalis-imx8Apalis iMX8
colibri-imx7-emmcColibri iMX7D 1GB (equipped with eMMC flash)
colibri-imx6Colibri iMX6
colibri-imx6ull-emmcColibri iMX6ULL 1GB (equipped with eMMC flash) [1]
colibri-imx8xColibri iMX8X V1.0C or newer
verdin-imx8mmVerdin iMX8M Mini
verdin-imx8mpVerdin iMX8M Plus
  • [1] Added on the 5.4.0-devel-202109 (September 2021 monthly pre-release)

TorizonCore Image​

Supported image targets for bitbaking:

ImageDescription
torizon-core-dockerDefault image supported by Toradex

- Network Manager: NetworkManager
- Init system: systemd
- Container Engine: Docker
- OTA Framework: OSTree & Uptane
torizon-core-podmanExperimental image using Podman instead of Docker

Same Features as above except Container Engine is Podman

Build Process​

Choose from the tabs below to either do a native or a containerized build:

Prerequisites​

You must have a host PC configured with the following prerequisites:

Download Metadata​

To configure the scripts and download the build metadata, do:

$ mkdir ~/bin
$ PATH=~/bin:$PATH

$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
$ chmod a+x ~/bin/repo

In addition, make sure you have Git user name and e-mail configured:

$ git config --global user.email "you@example.com"
$ git config --global user.name "Your Name"

Run repo init to bring down the latest stable version of Repo. You must specify a URL for the manifest, which specifies the various repositories that will be placed within your working directory. Furthermore, a branch must be specified. Available manifest branches are listed in the above table.

To check out the latest TorizonCore release, including monthly pre-releases:

$ repo init -u https://git.toradex.com/toradex-manifest.git -b dunfell-5.x.y -m torizoncore/default.xml

Alternatively, if you want to work on a specific version, check out using tags. Find out available tags on the Git repository. See the example below for 5.6.0:

repo init -u https://git.toradex.com/toradex-manifest.git -b refs/tags/5.6.0 -m torizoncore/default.xml
tip

For reproducible builds, you should at least lock in on a specific version. If reproducible builds are critical for your use case, consider fetching all source code and storing it on a local machine after the setup.

A successful initialization will end with a message stating that Repo is initialized in your working directory. Your client directory should now contain a .repo directory where files such as the manifest will be kept.

To pull down the metadata sources to your working directory from the repositories as specified in the repo manifest, run:

$ repo sync --no-clone-bundle

When downloading from behind a proxy (which is common in some corporate environments), it might be necessary to explicitly specify the proxy that is then used by repo:

$ export HTTP_PROXY=http://<proxy_user_id>:<proxy_password>@<proxy_server>:<proxy_port>
$ export HTTPS_PROXY=http://<proxy_user_id>:<proxy_password>@<proxy_server>:<proxy_port>

More rarely, Linux clients experience connectivity issues, getting stuck in the middle of downloads (typically during "Receiving objects"). It has been reported that tweaking the settings of the TCP/IP stack and using non-parallel commands can improve the situation. You need root access to modify the TCP setting:

$ sudo sysctl -w net.ipv4.tcp_window_scaling=0
$ repo sync -j1

Setup Environment​

The default distribution (DISTRO) variable is automatically set based on the chosen MACHINE (either torizon or torizon-upstream). To choose another DISTRO, specify so in the below command, similar to MACHINE. For more information on available DISTROs please see the previous section TorizonCore Distro.

Setup the work environment by using the setup-environment script:

$ [MACHINE=<MACHINE>] source setup-environment [BUILDDIR]

If MACHINE is not provided, the script will list all possible machines and force one to be selected. For more information on available machines please consult the Machine list.

Start Building​

To build the TorizonCore image:

The above setup script should properly prepare the environment with correct defaults. Additionally you'll want to modify the conf/local.conf file by adding ACCEPT_FSL_EULA="1".

$ bitbake torizon-core-docker

Customization​

The Yocto Project can be quite defying and hard to use. In the following documentation, we cover some basic functionality that is likely you will have to go through during your development:

It does not replace the official Yocto Project documentation, though. At the end of the article Build a Reference Image with Yocto Project, we provide links to it, and you will most likely need to study it to some degree.

Custom Layers​

On TorizonCore all your custom layers must be version controlled by Git, due to how we include layer revision information with OSTree. More details are provided in the aforementioned article Hello World integration into OpenEmbedded.

Deploy to Torizon OTA​

This is a feature available on prime-tiers of the Torizon Platform Services. If you want to learn more about the Torizon Platform Services pricing and plans, please contact us.

Request access to evaluate the Torizon Platform Services premium features

To be able to deploy your custom image to Torizon OTA, you need to meet the following criteria:

  • Maintain the OSTree and Aktualizr references unchanged at your Yocto Build setup. They are responsible for the system update and OTA process.

Then, all you need from Yocto is the resulting image in the Toradex Easy Installer format, which you will use with the TorizonCore Builder Tool to unpack the image and then push it to Torizon OTA.

Read the article Signing and Pushing TorizonCore Images to Torizon OTA for more details about this process.

Keep in mind, though, that once you build your own TorizonCore image you are fully responsible for regularly building and deploying updates as well.

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