EmbeddedPkg/Library/NvVarStoreFormattedLib/NvVarStoreFormattedLib.c

   1 /** @file
   2   A hook-in library for:
   3   - MdeModulePkg/Universal/Variable/Pei/VariablePei.inf
   4   - MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
   5   - MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
   6
   7   Plugging this library instance into one of the above modules makes that
   8   variable service backend wait for another platform module to dynamically
   9   initialize or verify EFI_FIRMWARE_VOLUME_HEADER and VARIABLE_STORE_HEADER in
  10   the non-volatile variable store FVB device. The initialization / verification
  11   is signaled by installing gEdkiiNvVarStoreFormattedGuid into the
  12   phase-matching PPI or protocol database, with a NULL interface. (Note that
  13   installing gEdkiiNvVarStoreFormattedGuid into either the DXE or the MM
  14   protocol database will unblock VariableSmm -- refer to EFI_SECTION_MM_DEPEX
  15   in the PI spec.)
  16
  17   Copyright (C) 2018, Red Hat, Inc.
  18
  19   This program and the accompanying materials are licensed and made available
  20   under the terms and conditions of the BSD License which accompanies this
  21   distribution. The full text of the license may be found at
  22   http://opensource.org/licenses/bsd-license.php
  23
  24   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  25   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  26 **/
  27
  28 #include <Base.h>
  29
  30 RETURN_STATUS
  31 EFIAPI
  32 NvVarStoreFormattedInitialize (
  33   VOID
  34   )
  35 {
  36   //
  37   // Do nothing, just imbue VariablePei / VariableRuntimeDxe / VariableSmm with
  38   // a PPI or protocol dependency on EDKII_NV_VAR_STORE_FORMATTED_GUID.
  39   //
  40   return RETURN_SUCCESS;
  41 }