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

Demystifying per-CPU interrupts

The most common ARM interrupt controller, GIC in the ARM multi-core processor, supports three types of interrupts:

  • CPU private interrupts: These interrupts are private per CPU. If triggered, such a per-CPU interrupt will exclusively be serviced on the target CPU or CPU to which it is bound. Private interrupts can be split into two families:
    • Private peripheral interrupts (PPIs): These are private and can only be generated by hardware bound to the CPU.
    • Software-generated interrupts (SGIs): Unlike PPIs, these are generated by the software. Thanks to this, SGIs are usually used as interrupt IPIs for inter-core communication on multi-core systems, meaning that one CPU can generate an interrupt (by writing the appropriate message, made of the interrupt ID and the target CPU to the GIC controller) to (an)other CPU(s). This is what we will talk about in this section.
  • Shared peripheral interrupts (SPIs) (not to be confused with the SPI bus): These...