audk/EdkCompatibilityPkg/Compatibility/ReadOnlyVariable2OnReadOnlyVariableThunk/ReadOnlyVariable2OnReadOnlyVariableThunk.c

/** @file
Module produce EFI_PEI_READ_ONLY_VARIABLE2_PPI on top of EFI_PEI_READ_ONLY_VARIABLE_PPI.
UEFI PI Spec supersedes Intel's Framework Specs. 
EFI_PEI_READ_ONLY_VARIABLE_PPI defined in Intel Framework Pkg is replaced by EFI_PEI_READ_ONLY_VARIABLE2_PPI
in MdePkg.
This module produces EFI_PEI_READ_ONLY_VARIABLE2_PPI on top of EFI_PEI_READ_ONLY_VARIABLE_PPI. 
This module is used on platform when both of these two conditions are true:
1) Framework module produces EFI_PEI_READ_ONLY_VARIABLE_PPI is present.
2) The platform has PI modules that only consumes EFI_PEI_READ_ONLY_VARIABLE2_PPI.

This module can't be used together with ReadOnlyVariableToReadOnlyVariable2Thunk module.


Copyright (c) 2006 - 2008 Intel Corporation. <BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:

**/

#include <PiPei.h>
#include <Ppi/ReadOnlyVariable2.h>
#include <Ppi/ReadOnlyVariable.h>
#include <Ppi/ReadOnlyVariableThunkPresent.h>
#include <Library/DebugLib.h>
#include <Library/PeiServicesTablePointerLib.h>
#include <Library/PeiServicesLib.h>

//
// Function Prototypes
//
EFI_STATUS
EFIAPI
PeiGetVariable (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN CONST  CHAR16                          *VariableName,
  IN CONST  EFI_GUID                        *VariableGuid,
  OUT       UINT32                          *Attributes,
  IN OUT    UINTN                           *DataSize,
  OUT       VOID                            *Data
  );

EFI_STATUS
EFIAPI
PeiGetNextVariableName (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN OUT UINTN                              *VariableNameSize,
  IN OUT CHAR16                             *VariableName,
  IN OUT EFI_GUID                           *VariableGuid
  );

//
// Module globals
//
EFI_PEI_READ_ONLY_VARIABLE2_PPI mVariablePpi = {
  PeiGetVariable,
  PeiGetNextVariableName
};

EFI_PEI_PPI_DESCRIPTOR     mPpiListVariable = {
  (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
  &gEfiPeiReadOnlyVariable2PpiGuid,
  &mVariablePpi
};


EFI_PEI_PPI_DESCRIPTOR     mReadOnlyVariableThunkPresent = {
    (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
    &gPeiReadonlyVariableThunkPresentPpiGuid,
    NULL
};

/**
  User entry for this PEIM driver.
  
  @param  FileHandle  Handle of the file being invoked.
  @param  PeiServices Describes the list of possible PEI Services.

  @retval EFI_SUCCESS ReadOnlyVariable2 PPI is successfully installed.
  @return Others      ReadOnlyVariable2 PPI is not successfully installed.

**/
EFI_STATUS
EFIAPI
PeimInitializeReadOnlyVariable2 (
  IN EFI_PEI_FILE_HANDLE       FfsHeader,
  IN CONST EFI_PEI_SERVICES    **PeiServices
  )
{
  VOID        *Interface;
  EFI_STATUS  Status;
  //
  // This thunk module can only be used together with a PI PEI core, as we 
  // assume PeiServices Pointer Table can be located in a standard way defined
  // in PI spec.
  //
  ASSERT ((*PeiServices)->Hdr.Revision >= 0x00010000);

  //
  // Make sure ReadOnlyVariable2ToReadOnlyVariable module is not present. If so, the call chain will form a
  // infinite loop: ReadOnlyVariable2 -> ReadOnlyVariable -> ReadOnlyVariable2 -> ....
  //
  Status = PeiServicesLocatePpi (&gPeiReadonlyVariableThunkPresentPpiGuid, 0, NULL, &Interface);
  ASSERT (Status == EFI_NOT_FOUND);
  
  Status = PeiServicesInstallPpi (&mReadOnlyVariableThunkPresent);
  ASSERT_EFI_ERROR (Status);
  
  //
  // Publish the variable capability to other modules
  //
  return PeiServicesInstallPpi (&mPpiListVariable);
}

/**
  Provide the read variable functionality of the variable services.

  @param  PeiServices           General purpose services available to every PEIM.
  @param  VariableName          The variable name
  @param  VendorGuid            The vendor's GUID
  @param  Attributes            Pointer to the attribute
  @param  DataSize              Size of data
  @param  Data                  Pointer to data

  @retval EFI_SUCCESS           The interface could be successfully installed
  @retval EFI_NOT_FOUND         The variable could not be discovered
  @retval EFI_BUFFER_TOO_SMALL  The caller buffer is not large enough

**/
EFI_STATUS
EFIAPI
PeiGetVariable (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN CONST  CHAR16                          *VariableName,
  IN CONST  EFI_GUID                        *VariableGuid,
  OUT       UINT32                          *Attributes,
  IN OUT    UINTN                           *DataSize,
  OUT       VOID                            *Data
  )
{
  EFI_STATUS                     Status;
  EFI_PEI_READ_ONLY_VARIABLE_PPI *ReadOnlyVariable;

  Status = PeiServicesLocatePpi (
             &gEfiPeiReadOnlyVariablePpiGuid,
             0,
             NULL,
             (VOID **)&ReadOnlyVariable
             );
  ASSERT_EFI_ERROR (Status);

  return ReadOnlyVariable->PeiGetVariable (
                             (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
                             (CHAR16 *)VariableName,
                             (EFI_GUID *)VariableGuid,
                             Attributes,
                             DataSize,
                             Data
                             );
}

/**
  Provide the get next variable functionality of the variable services.

  @param  PeiServices           General purpose services available to every PEIM.
  @param  VariabvleNameSize     The variable name's size.
  @param  VariableName          A pointer to the variable's name.
  @param  VariableGuid          A pointer to the EFI_GUID structure.
  @param  VariableNameSize      Size of the variable name
  @param  VariableName          The variable name
  @param  VendorGuid            The vendor's GUID

  @retval EFI_SUCCESS           The interface could be successfully installed
  @retval EFI_NOT_FOUND         The variable could not be discovered

**/
EFI_STATUS
EFIAPI
PeiGetNextVariableName (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN OUT UINTN                              *VariableNameSize,
  IN OUT CHAR16                             *VariableName,
  IN OUT EFI_GUID                           *VariableGuid
  )
{
  EFI_STATUS                     Status;
  EFI_PEI_READ_ONLY_VARIABLE_PPI *ReadOnlyVariable;

  Status = PeiServicesLocatePpi (
             &gEfiPeiReadOnlyVariablePpiGuid,
             0,
             NULL,
             (VOID **)&ReadOnlyVariable
             );
  ASSERT_EFI_ERROR (Status);

  return ReadOnlyVariable->PeiGetNextVariableName (
                             (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
                             VariableNameSize,
                             VariableName,
                             VariableGuid
                             );
}