PciBus

Overview

PciBus is the largest DXE driver in this set, implementing AMI's PCI bus enumeration and resource allocation for the UEFI platform. It manages the full PCI/PCIe bus hierarchy: device enumeration, bridge setup, Base Address Register (BAR) allocation, PCI Express link configuration (Gen2/Gen3/Gen4), SR-IOV capability handling, Option ROM loading and execution, and IOMMU/DMA protection initialization. The driver integrates with the S3 boot script library for PCI configuration restore across suspend/resume cycles.

Key Functions

• PciBusEntryPoint() -- DXE driver entry point; initializes protocol registration
• ProcessDriverInit() -- Driver initialization; configures DMA protection and CPU flags
• PciBusDriverBindingSupported() -- Tests if a controller is a PCI root bridge
• PciBusDriverBindingStart() -- Enumerates the PCI bus hierarchy beneath a root bridge
• PciBusDriverBindingStop() -- Stops the driver and releases PCI resources
• PciBusResourceAlloc() -- Allocates PCI bus resources (MMIO, I/O, bus numbers)
• PciBusBarHandling() -- Programs PCI Base Address Registers
• PciBusOptionRomLoad() -- Loads and executes PCI Option ROMs
• PciBusS3BootScript() -- Generates S3 boot script for PCI configuration save/restore
• PciBusIommuInit() -- Initializes IOMMU/DMA protection
• PciBusPcieGenConfig() -- Configures PCIe Gen2/Gen3/Gen4 link parameters

Dependencies

• AmiPciExpressLib -- AMI PCI Express library
• AmiPciExpressGen2Lib -- AMI PCI Express Gen2 configuration
• AmiPciExpressGen3Lib -- AMI PCI Express Gen3 configuration
• AmiSriovLib -- AMI SR-IOV (Single Root I/O Virtualization) library
• AmiPciBusLib -- AMI PCI bus common library
• PiDxeS3BootScriptLib -- S3 boot script library for PCI config save/restore
• SbPciHotPlugLib -- Southbridge PCI hot-plug library
• EFI_PCI_IO_PROTOCOL -- PCI I/O protocol (produced)
• EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL -- Root bridge I/O protocol (consumed)
• EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL -- Host bridge resource allocation

Platform

• Architecture: x86-64 (PE32+)
• Subsystem: EFI_BOOT_SERVICE_DRIVER (0x0B)
• Toolchain: VS2015, X64 DEBUG
• Source: AmiModulePkg, AmiCRBPkg (Southbridge), MdeModulePkg
• BIOS: HR650X (HR6N0XMLK)