Embedded Linux Development using Yocto Projects - Second Edition电子书

Title Page

Embedded Linux Development using Yocto Projects

Second Edition

Copyright

Embedded Linux Development using Yocto Projects

Second Edition

Credits

About the Authors

About the Reviewer

www.PacktPub.com

Why subscribe?

Customer Feedback

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the color images of this book

Errata

Piracy

Questions

Meeting the Yocto Project

What is the Yocto Project?

Delineating the Yocto Project

Understanding Poky

Using BitBake

OpenEmbedded-Core

Metadata

The alliance of the OpenEmbedded Project and the Yocto Project

Summary

Baking Our Poky-Based System

Configuring a host system

Installing Poky on Debian

Installing Poky on Fedora

Downloading the Poky source code

Preparing the build environment

Knowing the local.conf file

Building a target image

Running images in QEMU

Summary

Using Toaster to Bake an Image

What is Toaster?

Installing Toaster

Starting Toaster

Building an image to QEMU

Summary

Grasping the BitBake Tool

Understanding the BitBake tool

Exploring metadata

Parsing metadata

Dependencies

Preferring and providing recipes

Fetching the source code

Remote file downloads

Git repositories

Optimizing the source code download

Disabling network access

Understanding BitBake's tasks

Extending tasks

Generating a root filesystem image

Summary

Detailing the Temporary Build Directory

Detailing the build directory

Constructing the build directory

Exploring the temporary build directory

Understanding the work directory

Understanding the sysroot directories

Summary

Assimilating Packaging Support

Using supported package formats

List of supported package formats

Choosing a package format

Running code during package installation

Understanding shared state cache

Explaining package versioning

Specifying runtime package dependencies

Package feeds

Using package feeds

Summary

Diving into BitBake Metadata

Using metadata

Working with metadata

The basic variable setting

Variable expansion

Setting a default value using ?=

Setting a default value using ??=

Immediate variable expansion

Appending and prepending

Override syntax operators

Conditional metadata set

Conditional appending

File inclusion

Python variable expansion

Defining executable metadata

Defining Python functions in the global namespace

The inheritance system

Summary

Developing with the Yocto Project

Deciphering the software development kit

Working with the Poky SDK

Using an image-based SDK

Generic SDK – meta-toolchain

Using an SDK

Developing applications on the target

Integrating with Eclipse

Summary

Debugging with the Yocto Project

Differentiating metadata and application debugging

Tracking image, package, and SDK contents

Debugging packaging

Logging information during task execution

Utilizing a development shell

Using the GNU Project Debugger for debugging

Summary

Exploring External Layers

Powering flexibility with layers

Detailing the layer's source code

Adding meta layers

The Yocto Project layer ecosystem

Summary

Creating Custom Layers

Making a new layer

Adding metadata to the layer

Creating an image

Adding a package recipe

Automatically creating a base package recipe using recipetool

Adding support to a new machine definition

Wrapping an image for your machine

Using a custom distribution

MACHINE_FEATURES versus DISTRO_FEATURES

Understanding the variables scope

Summary

Customizing Existing Recipes

Common use cases

Adding extra options to recipes based on Autoconf

Applying a patch

Adding extra files to the existing packages

Understanding file searching paths

Changing recipe feature configuration

Customizing BusyBox

Customizing the linux-yocto framework

Summary

Achieving GPL Compliance

Understanding copyleft

Copyleft compliance versus proprietary code

Some guidelines for license compliance

Managing software licensing with Poky

Commercial licenses

Using Poky to achieve copyleft compliance

License auditing

Providing the source code

Providing compilation scripts and source code modifications

Providing license text

Summary

Booting Our Custom Embedded Linux

Exploring the boards

Discovering the right BSP layer

Baking for the hardware

Baking for BeagleBone Black

Baking for Raspberry Pi 3

Baking for the Wandboard

Booting our baked image

Booting BeagleBone Black from the SD card

Booting Raspberry Pi 3 from the SD card

Booting Wandboard from the SD card

Next steps

Summary