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

Introduction to PCI buses and interfaces

Peripheral Component Interconnect (PCI) is a local bus standard used to attach peripheral hardware devices to the computer system. As a bus standard, it defines how different peripherals of a computer should interact. However, over the years, the PCI standard has evolved either in terms of features or in terms of speed. As of its creation until now, we have had several bus families implementing the PCI standard, such as PCI (yes, the bus with the same name as the standard), and PCI Extended (PCI-X), PCI Express (PCIe or PCI-E), which is the current generation of PCI. A bus that follows PCI standards is known as a PCI bus.

From a software point of view, all these technologies are compatible and can be handled by the same kernel drivers. This means the kernel doesn't need to know which exact bus variant is used. PCIe greatly extends PCI with a lot of similarities from a software point of view (especially Read/Write I/O or Memory transactions...