Book Image

Linux Device Driver Development - Second Edition

By : John Madieu
Book Image

Linux Device Driver Development - Second Edition

By: John Madieu

Overview of this book

Linux is by far the most-used kernel on embedded systems. Thanks to its subsystems, the Linux kernel supports almost all of the application fields in the industrial world. This updated second edition of Linux Device Driver Development is a comprehensive introduction to the Linux kernel world and the different subsystems that it is made of, and will be useful for embedded developers from any discipline. You'll learn how to configure, tailor, and build the Linux kernel. Filled with real-world examples, the book covers each of the most-used subsystems in the embedded domains such as GPIO, direct memory access, interrupt management, and I2C/SPI device drivers. This book will show you how Linux abstracts each device from a hardware point of view and how a device is bound to its driver(s). You’ll also see how interrupts are propagated in the system as the book covers the interrupt processing mechanisms in-depth and describes every kernel structure and API involved. This new edition also addresses how not to write device drivers using user space libraries for GPIO clients, I2C, and SPI drivers. By the end of this Linux book, you’ll be able to write device drivers for most of the embedded devices out there.
Table of Contents (23 chapters)
1
Section 1 -Linux Kernel Development Basics
6
Section 2 - Linux Kernel Platform Abstraction and Device Drivers
12
Section 3 - Making the Most out of Your Hardware
18
Section 4 - Misc Kernel Subsystems for the Embedded World

Chapter 13: Demystifying the Kernel IRQ Framework

Linux is a system on which devices notify the kernel about events by means of interrupt requests (IRQs), though some devices are polled. The CPU exposes IRQ lines, shared or not, used by connected devices so that when a device needs the CPU, it sends a request to the CPU. When the CPU gets this request, it stops its actual job and saves its context, in order to serve the request issued by the device. After serving the device, its state is restored back to exactly where it stopped when the interruption occurred.

In this chapter, we will deal with the APIs that the kernel offers to manage IRQs and the ways in which multiplexing can be done. Moreover, we will analyze and look closer at interrupt controller driver writing.

To summarize, in this chapter, the following topics will be covered:

  • Brief presentation of interrupts
  • Understanding interrupt controllers and interrupt multiplexing
  • Diving into advanced peripheral...