Interfacing with Hardware Directly
Explore techniques for direct hardware access using I/O ports and memory-mapped I/O from within kernel-level code.
Why Talk Directly to Hardware?
In this lesson, we'll dive into how a CPU directly communicates with hardware devices. While your operating system usually handles this, kernel-level code and device drivers need to talk directly to components like network cards, graphics processors, or storage controllers.
This direct interaction is a powerful, low-level capability that forms the backbone of how your computer functions.
Two Ways to Talk to Hardware
The x86 architecture provides two main methods for the CPU to communicate with peripheral devices:
- I/O Ports: A dedicated, separate address space.
- Memory-Mapped I/O (MMIO): Device registers appear as locations within the CPU's main memory address space.
Both allow the CPU to read from and write to device registers, but they use different mechanisms and instructions.
All lessons in this course
- Introduction to Kernel Space
- Writing Simple Device Drivers
- Interfacing with Hardware Directly
- Synchronization and Concurrency in Kernel Space