procbuspci

Procbuspci is a term used to describe the interface and accompanying software and hardware components that connect a processor bus to a PCI bus within a computer system. It is most commonly encountered in embedded platforms and older PC architectures, where a dedicated processor-to-PCI bridge is required to allow the CPU to initiate transactions on PCI devices and to manage PCI configuration space access.

The typical procbuspci implementation includes a hardware bridge (or integrated chipset function) that translates processor-bus requests into PCI transactions and vice versa. It provides memory-mapped or I/O-mapped windows that expose PCI memory space and I/O space to the processor, as well as a mechanism to access the PCI configuration space for device enumeration and resource assignment. Interrupts from PCI devices are routed to the processor through an interrupt controller, and a DMA mechanism may be used to accelerate data transfer between the CPU and PCI devices.

Software support is generally provided by an operating system's PCI subsystem or a firmware/BIOS module. The OS must perform device enumeration, allocate resources, configure PCI devices, and ensure proper interrupt routing and memory protection. In modern systems, PCI Express and more integrated chipset designs have largely replaced traditional processor bus-to-PCI bridges; nevertheless, the core concept of bridging a host processor interface to a PCI/PCIe bus remains central in many embedded and industrial platforms.

Notes: the exact definition and implementation of procbuspci vary by vendor and platform, so documentation should be consulted for specific hardware.