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

Advanced Char Driver Operations

In previous chapters, we learned several useful things that can be handy in device driver development; however, a final step is needed. We must see how to add advanced functionalities to our character device and fully understand how we can synchronize user space processes with the peripheral I/O activity.

In this chapter, we'll see how to implement system calls for the lseek(), ioctl(), and mmap() functions, and we'll also get to know several techniques to put a process to sleep, just in case our peripheral does not yet have data to return to it; therefore, in this chapter, we will cover the following recipes:

  • Going up and down within a file with lseek()
  • Using ioctl() for custom commands
  • Accessing I/O memory with mmap()
  • Locking with the process context
  • Locking (and syncing) with the interrupt context
  • Waiting for I/O operations with poll...