[PATCH v7 08/17] OvmfPkg: Add PlatformHasIoMmuLib

[Brijesh Singh <brijesh.singh@amd.com>]

Add the shorter-term library instance outlined in the previous patch to
OvmfPkg, so that we can imbue PciHostBridgeDxe with a protocol dependency
on gEdkiiIoMmuProtocolGuid OR gIoMmuAbsentProtocolGuid.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.inf | 38 ++++++++++++++++++++
 OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c   | 33 +++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.inf b/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.inf
new file mode 100644
index 000000000000..f8151cfe2594
--- /dev/null
+++ b/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.inf
@@ -0,0 +1,38 @@
+## @file
+# A hook-in library for MdeModulePkg/Bus/Pci/PciHostBridgeDxe.
+#
+#  Plugging this library instance into PciHostBridgeDxe makes
+#  PciHostBridgeDxe depend on the platform's dynamic decision whether
+#  to provide IOMMU implementation (usually through IoMmuDxe driver).
+#
+# Copyright (C) 2017, Red Hat, Inc.
+# Copyright (C) 2017, AMD, Inc.
+#
+# 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.
+##
+
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = PlatformHasIoMmuLib
+  FILE_GUID                      = 49b4b018-0558-448b-1e1a-12226342877d
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PlatformHasIoMmuLib|DXE_DRIVER
+  CONSTRUCTOR                    = PlatformHasIoMmuInitialize
+
+[Sources]
+  PlatformHasIoMmuLib.c
+
+[Packages]
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[Depex]
+  gEdkiiIoMmuProtocolGuid OR gIoMmuAbsentProtocolGuid
diff --git a/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c b/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c
new file mode 100644
index 000000000000..a271be3e8aa3
--- /dev/null
+++ b/OvmfPkg/Library/PlatformHasIoMmuLib/PlatformHasIoMmuLib.c
@@ -0,0 +1,33 @@
+/** @file
+  A hook-in library for MdeModulePkg/Bus/Pci/PciHostBridgeDxe.
+
+  Plugging this library instance into PciHostBridgeDxe makes
+  PciHostBridgeDxe depend on the platform's dynamic decision whether
+  to provide IOMMU implementation (usually through IoMmuDxe driver).
+
+  Copyright (C) 2017, Red Hat, Inc.
+  Copyright (C) 2017, AMD, Inc.
+
+  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.
+**/
+
+#include <Base.h>
+
+RETURN_STATUS
+EFIAPI
+PlatformHasIoMmuInitialize (
+  VOID
+  )
+{
+  //
+  // Do nothing, just imbue PciHostBridgeDxe with a protocol dependency on
+  // gIoMmuAbsentProtocolGuid OR gEdkiiIoMmuProtocolGuid.
+  //
+  return RETURN_SUCCESS;
+}
-- 
2.7.4