You're reading from Mastering Linux Device Driver Development Write custom device drivers to support computer peripherals in Linux operating systems

Product type Paperback

Published in Jan 2021

Publisher Packt

ISBN-13 9781789342048

Length 646 pages

Edition 1st Edition

Languages

C++

Tools

Linux

Concepts

Embedded Systems

Author (1):

John Madieu

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Table of Contents (19) Chapters

Preface

1. Section 1:Kernel Core Frameworks for Embedded Device Driver Development

2. Chapter 1: Linux Kernel Concepts for Embedded Developers FREE CHAPTER

3. Chapter 2: Leveraging the Regmap API and Simplifying the Code

4. Chapter 3: Delving into the MFD Subsystem and Syscon API

5. Chapter 4: Storming the Common Clock Framework

6. Section 2: Multimedia and Power Saving in Embedded Linux Systems

7. Chapter 5: ALSA SoC Framework – Leveraging Codec and Platform Class Drivers

8. Chapter 6: ALSA SoC Framework – Delving into the Machine Class Drivers

9. Chapter 7: Demystifying V4L2 and Video Capture Device Drivers

10. Chapter 8: Integrating with V4L2 Async and Media Controller Frameworks

11. Chapter 9:Leveraging the V4L2 API from the User Space

12. Chapter 10: Linux Kernel Power Management

13. Section 3: Staying Up to Date with Other Linux Kernel Subsystems

14. Chapter 11: Writing PCI Device Drivers

15. Chapter 12: Leveraging the NVMEM Framework

16. Chapter 13: Watchdog Device Drivers

17. Chapter 14: Linux Kernel Debugging Tips and Best Practices

18. Other Books You May Enjoy

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Chapter 13: Watchdog Device Drivers

A watchdog is a hardware (sometimes emulated by software) device intended to ensure the availability of a given system. It helps make sure that the system always reboots upon a critical hang, thus allowing to monitor the "normal" behavior of the system.

Whether it is hardware-based or emulated by software, the watchdog is, most of the time, nothing but a timer initialized with a reasonable timeout that should be periodically refreshed by software running on the monitored system. If for any reason the software stops/fails at refreshing the timer (and has not explicitly shut it down) before it expires (it runs to timeout), this will trigger a (hardware) reset of the whole system (the computer, in our case). Such a mechanism can even help with recovering from a kernel panic. By the end of this chapter, you will be able to do the following: