Intel Extensible Firmware Interface - Manual (Page 442)

Extensible Firmware Interface Specification
12-24 12/01/02 Version 1.10
EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read()
EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Write()
Summary
Enables a PCI driver to access PCI controller registers in a PCI root bridge’s configuration space.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_IO_MEM) (
IN EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL
*This,
IN EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_WIDTH Width,
IN UINT64 Address,
IN UINTN Count,
IN OUT VOID *Buffer
);
Parameters
This A pointer to the EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL .
Type EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL is defined in
Section 12.2.
Width Signifies the width of the memory operations. Type
EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_WIDTH is defined
in Section 12.2.
Address The address within the PCI configuration space for the PCI
controller. See Table 12-1 for the format of
Address .
Count The number of PCI configuration operations to perform. Bytes
moved is
Width size * Count , starting at Address .
Buffer For read operations, the destination buffer to store the results. For
write operations, the source buffer to write data from.