Intel Extensible Firmware Interface - Manual (Page 153)

Services — Boot Services
Version 1.10 12/01/02 5-55
NULL,
This->DriverBindingHandle,
ControllerHandle,
EFI_OPEN_PROTOCOL_TEST_PROTOCOL
);
//
// EFI_OPEN_PROTOCOL_BY_DRIVER example
//
Opens the XYZ I/O Protocol on ControllerHandle
// The driver that is opening the protocol is identified by the
// Driver Binding Protocol instance This. This->DriverBindingHandle
// identifies the agent that is opening the protocol interface, and it
// is opening this protocol on behalf of ControllerHandle.
// Possible return status codes:
// EFI_SUCCESS : The protocol was opened and returned in XyzIo
// EFI_UNSUPPORTED : The protocol is not present on ControllerHandle
// EFI_ALREADY_STARTED : The protocol is already opened by the driver
// EFI_ACCESS_DENIED : The protocol is managed by a different driver
//
Status = gBS->OpenProtocol (
ControllerHandle,
&gEfiXyzIoProtocol,
&XyzIo,
This->DriverBindingHandle,
ControllerHandle,
EFI_OPEN_PROTOCOL_BY_DRIVER
);
//
// EFI_OPEN_PROTOCOL_BY_DRIVER | EFI_OPEN_PROTOCOL_EXCLUSIVE example
//
Opens the XYZ I/O Protocol on ControllerHandle
// The driver that is opening the protocol is identified by the
// Driver Binding Protocol instance This. This->DriverBindingHandle
// identifies the agent that is opening the protocol interface, and it
// is opening this protocol on behalf of ControllerHandle.
// Possible return status codes:
// EFI_SUCCESS : The protocol was opened and returned in XyzIo. If
// a different driver had the XYZ I/O Protocol opened
// BY_DRIVER, then that driver was disconnected to
// allow this driver to open the XYZ I/O Protocol.
// EFI_UNSUPPORTED : The protocol is not present on ControllerHandle
// EFI_ALREADY_STARTED : The protocol is already opened by the driver
// EFI_ACCESS_DENIED : The protocol is managed by a different driver that
// already has the protocol opened with an EXCLUSIVE
// attribute.
//
Status = gBS->OpenProtocol (
ControllerHandle,
&gEfiXyzIoProtocol,
&XyzIo,
This->DriverBindingHandle,
ControllerHandle,
EFI_OPEN_PROTOCOL_BY_DRIVER | EFI_OPEN_PROTOCOL_EXCLUSIVE
);