Xudong-Huang / pcics

PCI configuration space access library

PCI configuration space

PCI configuration space is the underlying way that the Conventional PCI, PCI-X and PCI Express perform auto configuration of the cards inserted into their bus.

This library implements access to PCI configuration space and PCI Express extended configuration space.

Design

The library is divided into three parts:

• PCI 3.0 Compatible Configuration Space Header
• PCI Configuration Space Capabilities
• Extended Configuration Space Capabilities

Usage

use pcics::{
    DDR_OFFSET, ECS_OFFSET, Header, Capabilities, ExtendedCapabilities,
    capabilities::{
        CapabilityKind,
        bridge_subsystem_vendor_id::BridgeSubsystemVendorId
    },
    extended_capabilities::{
        ExtendedCapabilityKind,
        vendor_specific_extended_capability::VendorSpecificExtendedCapability
    },
};

let conf_space =
    include_bytes!(concat!(
        env!("CARGO_MANIFEST_DIR"),
        "/tests/data/device/8086_2030/config"
    ));

let header_data = &conf_space[..DDR_OFFSET];
let header = Header::try_from(header_data).unwrap();
assert_eq!((0x8086, 0x2030), (header.vendor_id, header.device_id));

let device_depended_region_data = &conf_space[DDR_OFFSET..ECS_OFFSET];
let mut caps = Capabilities::new(device_depended_region_data, header.capabilities_pointer);
let BridgeSubsystemVendorId { subsystem_vendor_id, .. } =
    caps.find_map(|c| {
        if let CapabilityKind::BridgeSubsystemVendorId(ssvid) = c.kind {
            Some(ssvid)
        } else {
            None
        }
    })
    .unwrap();
assert_eq!(0x8086, subsystem_vendor_id);

let ecs_data = &conf_space[ECS_OFFSET..];
let mut ecaps = ExtendedCapabilities::new(ecs_data);
let VendorSpecificExtendedCapability { header, .. } = ecaps
    .find_map(|c| {
        if let ExtendedCapabilityKind::VendorSpecificExtendedCapability(vsec) = c.kind {
            Some(vsec)
        } else {
            None
        }
    })
    .unwrap();
assert_eq!(0x0c, header.vsec_length);

More detailed usage in modules descriptions