OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c

   1 /** @file
   2   A hook-in library for MdeModulePkg/Bus/Pci/PciHostBridgeDxe.
   3
   4   Plugging this library instance into PciHostBridgeDxe makes
   5   PciHostBridgeDxe depend on the platform's dynamic decision whether
   6   to provide IOMMU implementation (usually through IoMmuDxe driver).
   7
   8   Copyright (C) 2017, Red Hat, Inc.
   9   Copyright (C) 2017, AMD, Inc.
  10
  11   This program and the accompanying materials are licensed and made available
  12   under the terms and conditions of the BSD License which accompanies this
  13   distribution. The full text of the license may be found at
  14   http://opensource.org/licenses/bsd-license.php
  15
  16   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  17   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  18 **/
  19
  20 #include <Base.h>
  21
  22 RETURN_STATUS
  23 EFIAPI
  24 PlatformHasIoMmuInitialize (
  25   VOID
  26   )
  27 {
  28   //
  29   // Do nothing, just imbue PciHostBridgeDxe with a protocol dependency on
  30   // gIoMmuAbsentProtocolGuid OR gEdkiiIoMmuProtocolGuid.
  31   //
  32   return RETURN_SUCCESS;
  33 }