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Yocto for Raspberry Pi

Yocto for Raspberry Pi

By : Pierre-Jean, Mabäcker
2 (4)
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Yocto for Raspberry Pi

Yocto for Raspberry Pi

2 (4)
By: Pierre-Jean, 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 (13 chapters)
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3
3. Mastering Baking with Hob and Toaster

Preferences and providers


Once BitBake has realized the "parsing" step (analyzing all the recipes), it must know how to build the target. It starts by looking through the PROVIDES variable set in the recipe files. The default PROVIDES value for a recipe is its name ( PN ).

Note

PN represents the name of the recipe; PR, the revision of the recipe; and PV, the version of the recipe. For example, when using the recipe rpio-gpio_0.5.9.bb, here is what the values will be:

${PN} = rpi-gpio

${PV} = 0.5.9

Sometimes, a target might have multiple providers. A common example is virtual/kernel, which is provided by each kernel recipe (check out meta-raspberrypi/tree/master/recipes-kernel/linux for further information). Each machine often selects the best kernel provider by using a line similar to the following in the machine configuration file. If we look into this following file (meta-raspberrypi / conf / machine / include /rpi-default-providers.inc), we can see some variables:

# RaspberryPi...
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