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

Managing helper functions

During device driver development, we may need to concatenate a string or to compute its length or just copy or move a memory region (or a string). To do these common operations in the user space, we can use several functions, such as strcat(), strlen(), memcpy() (or strcpy()), and so on, and Linux offers us similarly named functions, which, of course, are safely usable in the kernel. (Note that kernel code cannot be linked against userspace glibc libraries.)

In this recipe, we will see how to use some kernel helpers in order to manage strings within the kernel.

Getting ready

If we take a look inside kernel sources at the include file linux/include/linux/string.h, we can see a long list of usual userspace...