PCI bridge function driver (<tt>host-bridge.c</tt>)

Not the SoC host controller (PCI host controllers). This is the **RT_PCI_DRIVER_EXPORT** driver for PCI bridge functions (root ports, P2P bridges, certain virtual bridges).

Source: **components/drivers/pci/host-bridge.c**.

Matched devices

static const struct rt_pci_device_id host_bridge_pci_ids[] = {
    { RT_PCI_DEVICE_ID(PCI_VENDOR_ID_REDHAT, 0x0008) },
    { RT_PCI_DEVICE_CLASS(PCIS_BRIDGE_PCI_NORMAL, ~0) },
    { RT_PCI_DEVICE_CLASS(PCIS_BRIDGE_PCI_SUBTRACTIVE, ~0) },
    { RT_PCI_DEVICE_CLASS(((PCIS_SYSTEM_RCEC << 8) | 0x00), ~0) },
    { /* sentinel */ }
};

Vendor-specific bridge drivers should register narrower **rt_pci_device_id** entries before this generic match.

Probe / remove

Callback	Behavior
`host_bridge_probe`	`rt_pci_set_master(pdev)`; optional PM register
`host_bridge_remove`	`rt_pci_clear_master`
`host_bridge_shutdown`	PM unregister

No BAR programming here — windows configured during enumeration (PCI enumeration and drivers).

Power management (<tt>RT_USING_PM</tt>)

**host_bridge_pm_suspend / resume**: **rt_pci_enum_device** on bus, **rt_pci_enable_wake** per function (PCI power management).

Sleep	PCI state
Idle	D3hot
Light / Deep	D1
Standby	D2
Shutdown	D3cold

Component map

Layer	Location	Role
Host RC	`pci/host/`, `ecam.c`	Enumeration
Bridge function	`host-bridge.c`	Bus master + PM on bridge devfn
OFW INTx	`pci/ofw.c`	`interrupt-map`

Pitfalls

Issue	Mitigation
Expect BAR setup here	Done in core PCI
Generic class match	Override with specific driver if needed