Intel Extensible Firmware Interface - Manual (Page 251)

Protocols — EFI Driver Model
Version 1.10 12/01/02 9-9
Listed below is sample code of the Supported() function of device driver for a device on the
XYZ bus. The XYZ bus is abstracted with the EFI_XYZ_IO_PROTOCOL . Just the presence of
the EFI_XYZ_IO_PROTOCOL on ControllerHandle is enough to determine if this driver
supports ControllerHandle . The gBS variable is initialized in this driver’s entry point. See
Chapter 4.
extern EFI_GUID gEfiXyzIoProtocol;
EFI_BOOT_SERVICES_TABLE *gBS;
EFI_STATUS
AbcSupported (
IN EFI_DRIVER_BINDING_PROTOCOL *This,
IN EFI_HANDLE ControllerHandle,
IN EFI_DEVICE_PATH_PROTOCOL *RemainingDevicePath OPTIONAL
)
{
EFI_STATUS Status;
EFI_XYZ_IO_PROTOCOL *XyzIo;
Status = gBS->OpenProtocol (
ControllerHandle,
&gEfiXyzIoProtocol,
&XyzIo,
This->DriverBindingHandle,
ControllerHandle,
EFI_OPEN_PROTOCOL_BY_DRIVER
);
if (EFI_ERROR (Status)) {
return Status;
}
gBS->CloseProtocol (
ControllerHandle,
&gEfiXyzIoProtocol,
This->DriverBindingHandle,
ControllerHandle
);
return EFI_SUCCESS;
}