Intel Extensible Firmware Interface - Manual (Page 263)

Protocols — EFI Driver Model
Version 1.10 12/01/02 9-21
Listed below is sample code of the Stop() function of a device driver for a device on the XYZ
bus. The XYZ bus is abstracted with the EFI_XYZ_IO_PROTOCOL . This driver does allow the
EFI_XYZ_IO_PROTOCOL to be shared with other drivers, and just the presence of the
EFI_XYZ_IO_PROTOCOL on ControllerHandle is enough to determine if this driver
supports ControllerHandle . This driver installs the EFI_ABC_IO_PROTOCOL on
ControllerHandle in Start() . The gBS variable is initialized in this driver’s entry point.
See Chapter 4.
extern EFI_GUID gEfiXyzIoProtocol;
extern EFI_GUID gEfiAbcIoProtocol;
EFI_BOOT_SERVICES_TABLE *gBS;
EFI_STATUS
AbcStop (
IN EFI_DRIVER_BINDING_PROTOCOL *This,
IN EFI_HANDLE ControllerHandle
IN UINTN NumberOfChildren,
IN EFI_HANDLE *ChildHandleBuffer OPTIONAL
)
{
EFI_STATUS Status;
EFI_ABC_IO AbcIo;
EFI_ABC_DEVICE AbcDevice;
//
// Get our context back
//
Status = gBS->OpenProtocol (
ControllerHandle,
&gEfiAbcIoProtocolGuid,
&AbcIo,
This->DriverBindingHandle,
ControllerHandle,
EFI_OPEN_PROTOCOL_GET_PROTOCOL
);
if (EFI_ERROR (Status)) {
return EFI_UNSUPPORTED;
}
//
// Use Containment Record Macro to get AbcDevice structure from
// a pointer to the AbcIo structure within the AbcDevice structure.
//
AbcDevice = ABC_IO_PRIVATE_DATA_FROM_THIS (AbcIo);