After Training. Linux Device Drivers Development

Core Kernel & System Skills

1. Analyze and Navigate Kernel Source: Confidently explore, understand, and trace code within the official Linux kernel source tree.
2. Compile Custom Kernels & Modules: Build the Linux kernel from source and independently develop, compile, and manage out-of-tree kernel modules.
3. Master Kernel Memory Management: Correctly allocate and manage kernel memory (kmalloc, vmalloc), understanding the contexts in which to use each.
4. Implement Robust Concurrency: Write stable, thread-safe driver code by properly using synchronization primitives like mutexes, spinlocks, and semaphores.
5. Debug Kernel-Level Code: Effectively debug drivers by interpreting kernel oops messages, using printk, and leveraging kernel debugging tools.
6. Bridge Kernel and Userspace: Create stable APIs for applications to communicate with hardware through sysfs, procfs, and ioctl commands.
7. Handle Hardware Interrupts: Write efficient interrupt service routines (ISRs) to respond to asynchronous hardware events in real-time.

Hardware Bus & Protocol Driver Development

8. Develop I2C Client Drivers: Write drivers to interface with a wide range of sensors, EEPROMs, and other peripherals on the I2C bus.
9. Develop SPI Device Drivers: Create drivers for high-speed devices on the SPI bus, managing data transfers and chip selects.
10. Write PCI/PCIe Drivers: Develop drivers for high-performance, auto-discoverable hardware, managing configuration space and memory-mapped I/O regions (BARs).
11. Create Complex USB Drivers: Write drivers for various USB devices, managing interfaces, endpoints, and asynchronous communication via USB Request Blocks (URBs).
12. Implement CAN Bus Drivers: Integrate systems with automotive and industrial networks by writing drivers for the CAN bus using the SocketCAN framework.
13. Develop Platform Drivers for SoCs: Write drivers for embedded, non-discoverable peripherals using the Linux device model and parse hardware data from the Device Tree.
14. Write Drivers for Legacy Ports: Create drivers for standard Serial (UART) and Parallel port devices.

Storage and Filesystem Driver Skills

15. Understand the Block I/O Layer: Gain a deep understanding of the Linux storage stack, including request queues and bio structures.
16. Write Custom Block Drivers: Develop a complete block device driver from scratch, starting with a fundamental RAM disk.
17. Create Drivers for Flash Memory: Write specialized drivers for flash storage cards, accounting for the unique characteristics of flash technology.
18. Develop Drivers for SD/MMC Cards: Implement a full-featured block driver to interface with the industry-standard SD/MMC protocol.

Network Driver Development

19. Build Ethernet Network Drivers: Write drivers for Network Interface Cards (NICs), managing packet transmission and reception using sk_buff structures.
20. Implement High-Performance Networking: Utilize modern kernel APIs like NAPI to write efficient, low-latency network drivers that avoid unnecessary overhead.
21. Develop WiFi Device Drivers: Create complex wireless networking drivers from scratch using advanced kernel frameworks like mac80211.

Project & Architectural Skills

22. Control Hardware Directly (GPIO): Write low-level drivers to control GPIO pins for tasks like blinking LEDs, reading buttons, and triggering events.
23. Manage Hardware Resources: Properly request, map, and release system resources like I/O memory and IRQ lines.
24. Read and Interpret Datasheets: Translate hardware datasheets and technical manuals into functional C code for a device driver.
25. Architect Driver Solutions: Apply their broad knowledge to design and architect the most appropriate driver type and structure for any given piece of custom hardware.