Protocol - 1

Description

In UEFI Spec., locate protocl with following declaration.
typedef
EFI_STATUS
(EFIAPI *EFI_LOCATE_PROTOCOL)(
  IN  EFI_GUID  *Protocol,
  IN  VOID      *Registration, OPTIONAL
  OUT VOID      **Interface
  );

In EfiPy, it has this mapping declaration.
EFI_LOCATE_PROTOCOL = CFUNCTYPE (
  EFI_STATUS,
  POINTER(EFI_GUID),  # IN  *Protocol
  PVOID,              # IN  *Registration, OPTIONAL
  POINTER(PVOID)      # OUT **Interface
  )

Above, First argument (EFI_STATUS) is function return type.

By ctypes implementation, C language data structure is strong type.
Define PVOID object before locate protocol and transfer it to wanted protocol data object by ctypes cast() function after locate protocol success.

Sample Code

import EfiPy2 as EfiPy

Interface = EfiPy.PVOID ()
Status = EfiPy.gBS.LocateProtocol (
           EfiPy.byref (gEfiSimpleTextOutProtocolGuid),
           None,
           EfiPy.byref (Interface)
           )

TestConOut = EfiPy.cast (

               Interface,

               EfiPy.POINTER(EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL)

               )

screenshot

sample source code can be download from Github EfiPy2ProtocolSample1.py