Intel Extensible Firmware Interface - Manual (Page 768)

Extensible Firmware Interface Specification
18-8 12/01/02 Version 1.10
DEVICE_IO.Map()
Summary
Provides the device-specific addresses needed to access system memory.
Prototype
typedef
EFI_STATUS
(EFIAPI *EFI_IO_MAP) (
IN EFI_DEVICE_IO_INTERFACE *This,
IN EFI_IO_OPERATION_TYPE Operation,
IN EFI_PHYSICAL_ADDRESS *HostAddress,
IN OUT UINTN *NumberOfBytes,
OUT EFI_PHYSICAL_ADDRESS *DeviceAddress,
OUT VOID **Mapping
);
Parameters
This A pointer to the EFI_DEVICE_IO_INTERFACE instance. Type
EFI_DEVICE_IO_INTERFACE is defined in Section 18.2.
Operation Indicates if the bus master is going to read or write to system memory.
Type
EFI_IO_OPERATION_TYPE is defined in “Related Definitions”
below.
HostAddress The system memory address to map to the device. Type
EFI_PHYSICAL_ADDRESS is defined in Chapter 5.
NumberOfBytes On input the number of bytes to map. On output the number of bytes
that were mapped.
DeviceAddress The resulting map address for the bus master device to use to access the
hosts
HostAddress . Type EFI_PHYSICAL_ADDRESS is defined in
Chapter 5.
Mapping A resulting value to pass to Unmap() .