Chapter 13: Demystifying the Kernel IRQ Framework
Linux is a system on which devices notify the kernel about events by means of interrupt requests (IRQs), though some devices are polled. The CPU exposes IRQ lines, shared or not, used by connected devices so that when a device needs the CPU, it sends a request to the CPU. When the CPU gets this request, it stops its actual job and saves its context, in order to serve the request issued by the device. After serving the device, its state is restored back to exactly where it stopped when the interruption occurred.
In this chapter, we will deal with the APIs that the kernel offers to manage IRQs and the ways in which multiplexing can be done. Moreover, we will analyze and look closer at interrupt controller driver writing.
To summarize, in this chapter, the following topics will be covered:
- Brief presentation of interrupts
- Understanding interrupt controllers and interrupt multiplexing
- Diving into advanced peripheral...
