[PATCH 1/2] MdePkg: Initial Version of MM Communication Protocol.

[Supreeth Venkatesh <supreeth.venkatesh@arm.com>]

This patch adds initial version of MM Communication Protocol as defined
in PI v1.5 Specification Volume 4.
Also, It includes MM Communication Protocol in MdePkg dec file.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Supreeth Venkatesh <supreeth.venkatesh@arm.com>
---
 MdePkg/Include/Protocol/MmCommunication.h | 75 +++++++++++++++++++++++++++++++
 MdePkg/MdePkg.dec                         |  3 ++
 2 files changed, 78 insertions(+)
 create mode 100644 MdePkg/Include/Protocol/MmCommunication.h

diff --git a/MdePkg/Include/Protocol/MmCommunication.h b/MdePkg/Include/Protocol/MmCommunication.h
new file mode 100644
index 0000000..ea3ba10
--- /dev/null
+++ b/MdePkg/Include/Protocol/MmCommunication.h
@@ -0,0 +1,75 @@
+/** @file
+  EFI MM Communication Protocol as defined in the PI 1.5 specification.
+
+  This protocol provides a means of communicating between drivers outside of MM and MMI
+  handlers inside of MM.
+
+  Copyright (c) 2016 - 2017, ARM Limited. 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.
+
+**/
+
+#ifndef _MM_COMMUNICATION_H_
+#define _MM_COMMUNICATION_H_
+
+//
+// Need include this header file for EFI_MM_COMMUNICATE_HEADER data structure.
+//
+#include <Uefi/UefiAcpiDataTable.h>
+
+#define EFI_MM_COMMUNICATION_PROTOCOL_GUID \
+  { \
+    0xc68ed8e2, 0x9dc6, 0x4cbd, { 0x9d, 0x94, 0xdb, 0x65, 0xac, 0xc5, 0xc3, 0x32 } \
+  }
+
+typedef struct _EFI_MM_COMMUNICATION_PROTOCOL  EFI_MM_COMMUNICATION_PROTOCOL;
+
+/**
+  Communicates with a registered handler.
+
+  This function provides a service to send and receive messages to the
+  MM environment from a registered UEFI service. This function is part
+  of the MM Communication Protocol that may be called in physical mode prior to
+  SetVirtualAddressMap() and in virtual mode after SetVirtualAddressMap().
+
+  @param[in]      This                The EFI_MM_COMMUNICATION_PROTOCOL instance.
+  @param[in, out] CommBuffer          A pointer to the buffer to convey into MMRAM.
+  @param[in, out] CommSize            The size of the data buffer being passed in.On exit, the size of data
+                                      being returned. Zero if the handler does not wish to reply with any data. This
+                                      parameter is optional and  may be NULL.
+
+  @retval EFI_SUCCESS                 The message was successfully posted.
+  @retval EFI_INVALID_PARAMETER       The CommBuffer was NULL.
+  @retval EFI_BAD_BUFFER_SIZE         The buffer is too large for the MM implementation. If this error is
+                                      returned, the MessageLength field in the CommBuffer header or the integer
+                                      pointed by CommSize are updated to reflect the maximum payload size the
+                                      implementation can accommodate.
+  @retval EFI_ACCESS_DENIED           The CommunicateBuffer parameter or CommSize parameter, if not omitted,
+                                      are in address range that cannot be accessed by the MM environment
+**/
+typedef
+EFI_STATUS
+(EFIAPI *EFI_MM_COMMUNICATE)(
+  IN CONST EFI_MM_COMMUNICATION_PROTOCOL   *This,
+  IN OUT VOID                              *CommBuffer,
+  IN OUT UINTN                             *CommSize    OPTIONAL
+  );
+
+//
+// EFI MM Communication Protocol provides runtime services for communicating
+// between DXE drivers and a registered MMI/SMI handler.
+//
+struct _EFI_MM_COMMUNICATION_PROTOCOL {
+  EFI_MM_COMMUNICATE  Communicate;
+};
+
+extern EFI_GUID gEfiMmCommunicationProtocolGuid;
+
+#endif
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 7a7504b..149783b 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -1050,6 +1050,9 @@
   ## Include/Protocol/SmmCommunication.h
   gEfiSmmCommunicationProtocolGuid  = { 0xc68ed8e2, 0x9dc6, 0x4cbd, { 0x9d, 0x94, 0xdb, 0x65, 0xac, 0xc5, 0xc3, 0x32 }}
 
+  ## Include/Protocol/MmCommunication.h
+  gEfiMmCommunicationProtocolGuid  = { 0xc68ed8e2, 0x9dc6, 0x4cbd, { 0x9d, 0x94, 0xdb, 0x65, 0xac, 0xc5, 0xc3, 0x32 }}
+
   ## Include/Protocol/SmmStatusCode.h
   gEfiSmmStatusCodeProtocolGuid   = { 0x6afd2b77, 0x98c1, 0x4acd, { 0xa6, 0xf9, 0x8a, 0x94, 0x39, 0xde, 0xf, 0xb1}}
 
-- 
2.7.4