Book Image

Linux Device Driver Development Cookbook

By : Rodolfo Giometti
Book Image

Linux Device Driver Development Cookbook

By: Rodolfo Giometti

Overview of this book

Linux is a unified kernel that is widely used to develop embedded systems. As Linux has turned out to be one of the most popular operating systems worldwide, the interest in developing proprietary device drivers has also increased. Device drivers play a critical role in how the system performs and ensure that the device works in the manner intended. By exploring several examples on the development of character devices, the technique of managing a device tree, and how to use other kernel internals, such as interrupts, kernel timers, and wait queue, you’ll be able to add proper management for custom peripherals to your embedded system. You’ll begin by installing the Linux kernel and then configuring it. Once you have installed the system, you will learn to use different kernel features and character drivers. You will also cover interrupts in-depth and understand how you can manage them. Later, you will explore the kernel internals required for developing applications. As you approach the concluding chapters, you will learn to implement advanced character drivers and also discover how to write important Linux device drivers. By the end of this book, you will be equipped with the skills you need to write a custom character driver and kernel code according to your requirements.
Table of Contents (14 chapters)
10
Additional Information: Managing Interrupts and Concurrency

Installing the Development System

In this chapter, we will present and set up our working platform. In fact, even if we write and then test our own device drivers on our working PC, it is recommended to use a second device to test the code. This is because we're going to work in the kernel space where even a little bug can cause severe malfunctioning! Also, using a platform where several kinds of peripherals are available allows us to test a large variety of devices that are not always available on a PC. Of course, you are free to use your own system to write and test your drivers but, in this case, you should take care of the modifications needed to fit your board specifications.

In this book, I'm going to use the Marvell ESPRESSObin system, which is a powerful Advanced RISC Machines (ARM) 64-bit machine with a lot of interesting features. In the following figure, you can see the ESPRESSObin alongside a credit card and can gain an idea about the real dimensions of the board:

My board is the v5 release of ESPRESSObin while the latest version at the time of writing (announced on September 2018) is v7, so the reader should be able to get this new release by the time this book is published. The new ESPRESSObin v7 will feature 1GB DDR4 and 2GB DDR4 configurations (while v5 has DDR3 RAM chips), and a new 1.2GHz chipset will replace the currently sold configurations, which sports 800MHz and 1GHz CPU frequency limits. Even by taking a quick look at the new board layout, we see that a single SATA connector has taken the place of the existing two-pieces combination of SATA power and interface, the LED layout is now rearranged in a row, and an on-board eMMC is now in place. Moreover, this new revision will ship with an optional 802.11ac + Bluetooth 4.2 mini PCIe Wi-Fi card, which is sold separately.

Lastly, you will now have the option to order your v7 ESPRESSObin with a complete enclosure. This product has FCC and CE certifications to help to enable mass deployment. Further information regarding the revision v7 (and v5) can be found at http://wiki.espressobin.net/tiki-index.php?page=Quick+User+Guide.

In order to test our new drivers, we will cover the following recipes in this first chapter:

  • Setting up the host machine
  • Working with the serial console
  • Configuring and building the kernel
  • Setting up the target machine
  • Doing native compiling on foreign hardware