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
About the Author
About the Reviewers

Finding the right device driver

A typical embedded board is based on a reference design from the manufacturer with changes to make it suitable for a particular application. It may have a temperature sensor attached via I2C, lights and buttons connected via GPIO pins, an external Ethernet MAC, a display panel via a MIPI interface, or many other things. Your job is to create a custom kernel to control all of that, so where do you start?

Some things are so simple that you can write user space code to handle them. GPIOs and simple peripherals connected via I2C or SPI are easy to control from user space, as I will explain later.

Other things need a kernel driver so you need to know how to find one and incorporate it into your build. There is no simple answer, but here are some places to look.

The most obvious place to look is the driver support page on the manufacturer's website, or you could ask them directly. In my experience, this seldom gets the result you want; hardware manufacturers are not...