Book Image

Mastering Embedded Linux Programming - Third Edition

By : Frank Vasquez, Chris Simmonds
5 (3)
Book Image

Mastering Embedded Linux Programming - Third Edition

5 (3)
By: Frank Vasquez, Chris Simmonds

Overview of this book

If you’re looking for a book that will demystify embedded Linux, then you’ve come to the right place. Mastering Embedded Linux Programming is a fully comprehensive guide that can serve both as means to learn new things or as a handy reference. The first few chapters of this book will break down the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. After that, you will learn how to create each of these elements from scratch and automate the process using Buildroot and the Yocto Project. As you progress, the book will show you how to implement an effective storage strategy for flash memory chips and install updates to a device remotely once it’s deployed. You’ll also learn about the key aspects of writing code for embedded Linux, such as how to access hardware from apps, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters demonstrate how to debug your code, whether it resides in apps or in the Linux kernel itself. You’ll also cover the different tracers and profilers that are available for Linux so that you can quickly pinpoint any performance bottlenecks in your system. By the end of this Linux book, you’ll be able to create efficient and secure embedded devices using Linux.
Table of Contents (27 chapters)
1
Section 1: Elements of Embedded Linux
10
Section 2: System Architecture and Design Decisions
18
Section 3: Writing Embedded Applications
22
Section 4: Debugging and Optimizing Performance

Summary

Linux has sophisticated power management functions. I have described four
main components:

  • CPUFreq changes the OPP of each processor core to reduce power on those that are busy but have some bandwidth to spare, and so allow the opportunity to scale the frequency back. OPPs are known as P-States in the ACPI specification.
  • CPUIdle selects deeper idle states when the CPU is not expected to be woken up for a while. Idle states are known as C-States in the ACPI specification.
  • Runtime pm will shut down peripherals that are not needed.
  • System sleep modes will put the whole system into a low power state. They are usually under end user control, for example, by pressing a standby button. System sleep states are known as S-States in the ACPI specification.

Most of the power management is done for you by the BSP. Your main task is to make sure that it is configured correctly for your intended use cases. Only the last component, selecting a system sleep state...