CHAPTER 16
Embedded Kernel Programming

In this chapter, you are introduced to Linux kernel programming on an embedded device such as a Beagle board. Kernel programming is an advanced topic that requires in-depth study of the source code for the Linux kernel; however, this chapter is structured as a practical step-by-step guide to the focused task of writing Linux loadable kernel modules (LKMs) that interface to general-purpose inputs/outputs (GPIOs). The first example is a straightforward “Hello World” module that can be used to establish a configuration for LKM development on the board. The second LKM example introduces interrupt service routines (ISRs) and interfaces a simple GPIO button and LED circuit to Linux kernel space. Two further examples are provided that introduce the kobject interface and the use of kernel threads to build kernel-space sysfs devices for the board. By the end of this chapter, you should be familiar with the steps required to write kernel code...