Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By : Alex Gonzalez
Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By: Alex Gonzalez

Overview of this book

The Yocto Project has become the de facto distribution build framework for reliable and robust embedded systems with a reduced time to market.You'll get started by working on a build system where you set up Yocto, create a build directory, and learn how to debug it. Then, you'll explore everything about the BSP layer, from creating a custom layer to debugging device tree issues. In addition to this, you’ll learn how to add a new software layer, packages, data, scripts, and configuration files to your system. You will then cover topics based on application development, such as using the Software Development Kit and how to use the Yocto project in various development environments. Toward the end, you will learn how to debug, trace, and profile a running system. This second edition has been updated to include new content based on the latest Yocto release.
Table of Contents (13 chapters)
Title Page
Packt Upsell

Managing the device tree

The device tree is a data structure that is passed to the Linux kernel to describe the physical devices in a system.

In this recipe, we will explain how to work with device trees.

Getting ready

Devices that cannot be discovered by the CPU are handled by the platform devices API on the Linux kernel. The device tree replaces the legacy platform data where hardware characteristics were hardcoded in the kernel source so that platform devices can be instantiated. Before device trees came into use, the bootloader (for example, U-Boot) had to tell the kernel what machine type it was booting. Moreover, it had to pass other information such as memory size and location, kernel command-line, and more.

The device tree was first used by the PowerPC architecture and was adopted later on by ARM and all others, except x86. It was defined by the Open Firmware specification, which defined the flattened device tree format in Standard for Embedded Power Architecture Platform Requirements...