Intel Extensible Firmware Interface - Manual (Page 485)

Protocols — PCI Bus Support
Version 1.10 12/01/02 12-67
EFI_PCI_IO_PROTOCOL.PollIo()
Summary
Reads from the I/O space of a PCI controller. Returns when either the polling exit criteria is
satisfied or after a defined duration.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_PCI_IO_PROTOCOL_POLL_IO_MEM) (
IN struct EFI_PCI_IO_PROTOCOL
*This,
IN EFI_PCI_IO_PROTOCOL_WIDTH Width,
IN UINT8 BarIndex,
IN UINT64 Offset,
IN UINT64 Mask,
IN UINT64 Value,
IN UINT64 Delay,
OUT UINT64 *Result
);
Parameters
This A pointer to the EFI_PCI_IO_PROTOCOL instance. Type
EFI_PCI_IO_PROTOCOL is defined in Section 12.4.
Width Signifies the width of the I/O operations. Type
EFI_PCI_IO_PROTOCOL_WIDTH is defined in Section 12.4.
BarIndex The BAR index of the standard PCI Configuration header to use as
the base address for the I/O operation to perform. This allows all
drivers to use BAR relative addressing. The legal range for this
field is 0..5. However, the value
EFI_PCI_IO_PASS_THROUGH_BAR can be used to bypass the
BAR relative addressing and pass Offset to the PCI Root Bridge
I/O Protocol unchanged. Type
EFI_PCI_IO_PASS_THROUGH_BAR is defined in Section 12.4.
Offset The offset within the selected BAR to start the I/O operation.
Mask Mask used for the polling criteria. Bytes above Width in Mask
are ignored. The bits in the bytes below Width which are zero in
Mask are ignored when polling the I/O address.