// 1. Enable the PCI device pci_enable_device(pdev); // 2. Request ownership of memory regions (BARs) pci_request_regions(pdev, "my_driver");
pci_release_regions(pdev); pci_disable_device(pdev); pci device driver
In modern computing, the Peripheral Component Interconnect (PCI) bus is the circulatory system of the motherboard. From GPUs and NVMe SSDs to network adapters and sound cards, almost every high-speed peripheral relies on PCI or its derivatives (PCIe). From GPUs and NVMe SSDs to network adapters
| Offset | Field | Purpose | |--------|-------|---------| | 0x00 | Vendor ID | Manufacturer (e.g., 0x10DE for NVIDIA) | | 0x02 | Device ID | Specific model (e.g., 0x1B80 for GTX 1080) | | 0x08 | Class Code | Device category (e.g., 0x030000 for VGA) | | 0x10 | BARs (Base Address Registers) | Memory/I/O addresses assigned by firmware | | 0x3C | Interrupt Line | Which IRQ the device is wired to | The driver matches the Vendor/Device ID against its internal table. A mismatch means the driver should ignore the device. 3. Key Responsibilities of a PCI Driver A. Probing – The Handshake The kernel calls the driver’s probe() function when a matching device is found. Inside probe() , the driver must: // 6. Initialize device-specific state my_device_init(regs)
// 5. Set up interrupt handler request_irq(pdev->irq, my_interrupt_handler, IRQF_SHARED, "my_driver", dev);
pci_enable_device(pdev); pci_request_regions(pdev, "my_pci_driver"); pci_iomap(pdev, 0, 0); return 0;
// 6. Initialize device-specific state my_device_init(regs);