Book Image

Mastering Embedded Linux Programming

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming

By: Chris Simmonds

Overview of this book

Mastering Embedded Linux Programming takes you through the product cycle and gives you an in-depth description of the components and options that are available at each stage. You will begin by learning about toolchains, bootloaders, the Linux kernel, and how to configure a root filesystem to create a basic working device. You will then learn how to use the two most commonly used build systems, Buildroot and Yocto, to speed up and simplify the development process. Building on this solid base, the next section considers how to make best use of raw NAND/NOR flash memory and managed flash eMMC chips, including mechanisms for increasing the lifetime of the devices and to perform reliable in-field updates. Next, you need to consider what techniques are best suited to writing applications for your device. We will then see how functions are split between processes and the usage of POSIX threads, which have a big impact on the responsiveness and performance of the final device The closing sections look at the techniques available to developers for profiling and tracing applications and kernel code using perf and ftrace.
Table of Contents (22 chapters)
Mastering Embedded Linux Programming
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Building the kernel


Having decided which kernel to base your build on, the next step is to build it.

Getting the source

Let's assume that you have a board that is supported in mainline. You can get the source code through git or by downloading a tarball. Using git is better because you can see the commit history, you can easily see any changes you may make and you can switch between branches and versions. In this example, we are cloning the stable tree and checking out the version tag 4.1.10:

$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git linux
$ cd linux
$ git checkout v4.1.10

Alternatively, you could download the tarball from https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.1.10.tar.xz.

There is a lot of code here. There are over 38,000 files in the 4.1 kernel containing C source code, header files, and assembly code, amounting to a total of over 12.5 million lines of code (as measured by the cloc utility). Nevertheless, it is worth knowing the basic...