This repository provides Repo manifests to setup the Yocto build system for the Gumstix products.
Note If you already have a Yocto setup and want only the Gumstix BSP layer, use the meta-gumstix repository found here: git://github.com/ashcharles/meta-gumstix.git.
Yocto allows the creation of custom Linux distributions for embedded systems including Gumstix-based systems. It is a collection of git repositories known as layers each of which provides recipes to build software packages as well as configuration information.
Repo is a tool that enables the management of many git repositories given a single manifest file. Tell Repo to fetch a manifest from this repository and it will fetch the git repositories specified in the manifest and, by doing so, setup a Yocto build environment for you!
1. Install Repo.
Download the Repo script.
$ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > repo
Make it executable.
$ chmod a+x repo
Move it on to your system path.
$ sudo mv repo /usr/local/bin/
If it is correctly installed, you should see a Usage message when invoke it with the help flag.
$ repo --help
2. Initialize a Repo client.
Create an empty directory to hold your working files.
$ mkdir yocto
$ cd yocto
Tell Repo where to find the manifest
$ repo init -u git://github.com/ashcharles/Gumstix-YoctoProject-Repo.git
A successful initialization will end with a message stating that Repo is initialized in your working directory. Your directory should now contain a .repo directory where repo control files such as the manifest are stored but you should not need to touch this directory.
Note You can use the -b switch to specify the branch of the repository to use. We develop on the guaranteed-to-break dev branch. The master branch should at least compile.
The -m switch selects the manifest file (default is default.xml). Our default.xml on master is designed to be stable as it pins particular commits.
To test out the bleeding edge, type:
$ repo init -u git://github.com/ashcharles/Gumstix-YoctoProject-Repo.git -b dev
$ repo sync
To get back to the known stable version, type:
$ repo init -u git://github.com/ashcharles/Gumstix-YoctoProject-Repo.git -b master
$ repo sync
To learn more about repo, look at http://source.android.com/source/version-control.html
3. Fetch all the repositories.
$ repo sync
Now go turn on the coffee machine as this may take 20 minutes depending on your connection.
4. Initialize the Yocto Environment.
$ TEMPLATECONF=meta-gumstix-extras/conf source ./poky/oe-init-build-env
This copies default configuration information into the poky/build/conf directory and sets up some environment variables for Yocto. This configuration directory is not under revision control; you may wish to edit these configuration files for your specific setup.
5. Build an image.
This process downloads several gigabytes of source code and then proceeds to do an awful lot of compilation so make sure you have plenty of space (25GB minimum), and expect a day or so of build time depending on your network connection. Don't worry---it is just the first build that takes a while.
$ bitbake gumstix-console-image
If everything goes well, you should have a compressed root filesystem tarball as well as kernel and bootloader binaries available in your work/deploy directory. If you run into problems, the most likely candidate is missing software packages. Check out http://www.yoctoproject.org/docs/current/yocto-project-qs/yocto-project-qs.html#resources for the list of required packages for operating system. Also, take a look to be sure your operating system is supported: https://wiki.yoctoproject.org/wiki/Distribution_Support
To pick up the latest changes for all source repositories, run:
$ repo sync
Enter the Yocto environment:
$ source poky/oe-init-build-env
If you forget to setup these environment variables prior to bitbaking, your OS will complain that it can't find bitbake on the path. Don't try to install bitbake using a package manager, just run the command above.
You can then rebuild as before:
$ bitbake gumstix-console-image
So something broke...
There are several degrees of starting fresh; individual packages can be rebuilt or the whole system can be reconstructed.
- clean a package: bitbake -c cleansstate
- re-download package: bitbake -c cleanall
- destroy everything but downloads: rm -rf build (or whereever your sstate and work directories are)
- destroy it all (not recommended): rm -rf build && rm -rf sources
Note If you've made a change to a recipe and want the package to be rebuilt, just increment the recipe version (the PR variable); cleaning is not necessary.
To understand better how bitbake processes recipes, look at the excellent documentation http://www.yoctoproject.org/docs/current/poky-ref-manual/poky-ref-manual.html.
To make sense of the differences between these cleaning methods, it is useful to understand that Yocto caches both the downloaded source files for all the packages it tries to build (the DL_DIR configuration parameter) and the packages once built (the SSTATE_DIR configuration parameter). Typically, deleting the downloaded source is a bad idea---this just means re-fetching gigabytes of code which wastes network bandwidth. Cleaning the sstate cache for a particular package ensures that it actually gets rebuilt from source rather than simply restored from the cache.
Sooner or later, you'll want to customize some aspect of the image either adding more packages, picking up some upstream patches, or tweaking your kernel. To this end, you'll want to customize the Repo manifest to point at different repositories and branches or pull in additional meta-layers.
Clone this repository (or fork it on github):
$ git clone git://github.com/ashcharles/Gumstix-YoctoProject-Repo.git
Make your changes (and contribute them back if they are generally useful :) ), and then re-initialize your repo client
$ repo init -u <file:///path/to/your/git/repository.git>