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

The Linux kernel PCI subsystem and data structures

The Linux kernel supports the PCI standard and provides APIs to deal with such devices. In Linux, the PCI implementation can be broadly divided into the following main components:

  • PCI BIOS: This is an architecture-dependent part in charge of kicking off the PCI bus initialization. ARM-specific Linux implementation lies in arch/arm/kernel/bios32.c. The PCI BIOS code interfaces with PCI Host Controller code as well as the PCI core in order to perform bus enumeration and the allocation of resources, such as memory and interrupts.

    The successful completion of BIOS execution guarantees that all the PCI devices in the system are assigned parts of available PCI resources and their respective drivers (referred to as slave or endpoint drivers) can take control of them using the facilities provided by the PCI core.

    Here, the kernel invokes the services of architecture and board-specific PCI functionalities. Two important tasks of PCI...