Book Image

Yocto for Raspberry Pi

By : TEXIER Pierre-Jean, Petter Mabäcker
Book Image

Yocto for Raspberry Pi

By: TEXIER Pierre-Jean, Petter Mabäcker

Overview of this book

The Yocto Project is a Linux Foundation workgroup, which produces tools (SDK) and processes (configuration, compilation, installation) that will enable the creation of Linux distributions for embedded software, independent of the architecture of embedded software (Raspberry Pi, i.MX6, and so on). It is a powerful build system that allows you to master your personal or professional development. This book presents you with the configuration of the Yocto Framework for the Raspberry Pi, allowing you to create amazing and innovative projects using the Yocto/ OpenEmbedded eco-system. It starts with the basic introduction of Yocto's build system, and takes you through the setup and deployment steps for Yocto. It then helps you to develop an understanding of Bitbake (the task scheduler), and learn how to create a basic recipe through a GPIO application example. You can then explore the different types of Yocto recipe elements (LICENSE, FILES, SRC_URI, and so on). Next, you will learn how to customize existing recipes in Yocto/OE layers and add layers to your custom environment (qt5 for example).
Table of Contents (18 chapters)
Yocto for Raspberry Pi
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
3
Mastering Baking with Hob and Toaster

The basic concepts of layers


Let's dive into the basic concepts of layers:

Theory

A layer, in the technical sense of the term, has some properties. They are as follows:

  • Name: This usually starts with the string meta- (mandatory for better comprehension).

  • Priority: This is the value used by BitBake to decide which recipe to use and the order in which the .bbappend files should be joined. It means that if two layers include the same recipe (.bb) file, the one with the higher priority is used.

Note

For example, a layer with a priority value set to 6 has a higher chance of its recipe being used than one with a priority value set to 5.

Furthermore, each layer is listed according to its functionality on this page:

http://layers.openembedded.org/layerindex/branch/master/layers/

  • The software layer:  This layer provides software families that can be used on any architecture (x86_64, ARM, PPC, MIPS, and so on). For example, we have meta-java (for Java support), meta-efl (for the Enlightenment environment...