Book Image

Mastering Linux Device Driver Development

By : John Madieu
Book Image

Mastering Linux Device Driver Development

By: John Madieu

Overview of this book

Linux is one of the fastest-growing operating systems around the world, and in the last few years, the Linux kernel has evolved significantly to support a wide variety of embedded devices with its improved subsystems and a range of new features. With this book, you’ll find out how you can enhance your skills to write custom device drivers for your Linux operating system. Mastering Linux Device Driver Development provides complete coverage of kernel topics, including video and audio frameworks, that usually go unaddressed. You’ll work with some of the most complex and impactful Linux kernel frameworks, such as PCI, ALSA for SoC, and Video4Linux2, and discover expert tips and best practices along the way. In addition to this, you’ll understand how to make the most of frameworks such as NVMEM and Watchdog. Once you’ve got to grips with Linux kernel helpers, you’ll advance to working with special device types such as Multi-Function Devices (MFD) followed by video and audio device drivers. By the end of this book, you’ll be able to write feature-rich device drivers and integrate them with some of the most complex Linux kernel frameworks, including V4L2 and ALSA for SoC.
Table of Contents (19 chapters)
1
Section 1:Kernel Core Frameworks for Embedded Device Driver Development
6
Section 2: Multimedia and Power Saving in Embedded Linux Systems
13
Section 3: Staying Up to Date with Other Linux Kernel Subsystems

Chapter 11: Writing PCI Device Drivers

A PCI is more than just a bus. It is a standard with a complete set of specifications defining how different parts of a computer should interact. Over the years, a PCI bus has become the de facto bus standard for device inter-connections, such that almost every SoC has native support for such buses. The need for speed led to different versions and generations of this bus.

In the early days of the standard, the first bus that implemented the PCI standard was the PCI bus (the bus name is the same as the standard), as a replacement for the ISA bus. This improved (with 32-bit addressing and jumper-less autodetection and configuration) the address limitation encountered with ISA (limited to 24 bits, and which occasionally necessitated playing with jumpers in order to route IRQs and so on). Compared with the previous bus implementation of the PCI standard, the major factor that has been improved is speed.

PCI Express is the current family of PCI...