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

Accessing flash memory from Linux

Raw NOR and NAND flash memory is handled by the Memory Technology Device subsystem, or MTD, which provides you with basic interfaces to read, erase, and write blocks of flash memory. In the case of NAND flash, there are also functions that handle the OOB area and are used to identify bad blocks.

For managed flash, you need drivers to handle a particular hardware interface. MMC/SD cards and eMMC use the mmcblk driver, while CompactFlash and hard drives use the SCSI disk driver, sd. USB flash drives use the usb_storage driver, together with the
sd driver.

Memory technology devices

The MTD subsystem was started by David Woodhouse in 1999 and has been extensively developed over the intervening years. In this section, I will concentrate on the way it handles the two main technologies, NOR and NAND flash.

MTD consists of three layers: a core set of functions, a set of drivers for various types of chips, and user-level drivers that present the...