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

Parsing metadata


The first thing BitBake does is parse base configuration metadata (.conf files). Base configuration metadata consists of the bblayers.conf file to determine what layers BitBake needs to recognize, all necessary layer.conf files (one from each layer), and bitbake.conf. The data itself is of various types:

  • Recipes: These contain details about particular pieces of software.

  • Class data: This provides an abstraction of common build information (for example, how to build a Linux kernel).

  • Configuration data: This provides machine-specific settings, policy decisions, and so forth. Configuration data acts as the glue that binds everything together.

The layer.conf files are used to construct key variables such as BBPATH and BBFILES. BBPATH is used to search for configuration and class files under the conf/ and class/ directories, respectively. BBFILES is used to find recipe files (.bb and .bbappend). If there is no bblayers.conf file, it is assumed that the user has set the BBPATH and...