StandaloneMmPkg: Add CPU driver suitable for ARM Platforms.

This patch adds a simple CPU driver that exports the
EFI_MM_CONFIGURATION_PROTOCOL to allow registration of the Standalone
MM Foundation entry point. It preserves the existing notification
mechanism for the configuration protocol.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Sughosh Ganu <sughosh.ganu@arm.com>
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Supreeth Venkatesh <supreeth.venkatesh@arm.com>
Reviewed-by: Achin Gupta <achin.gupta@arm.com>

StandaloneMmPkg/Drivers/StandaloneMmCpu/AArch64/StandaloneMmCpu.h

@@ -0,0 +1,64 @@
+/** @file
+  Private header with declarations and definitions specific to the MM Standalone
+  CPU driver
+
+  Copyright (c) 2017 - 2018, 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 _ARM_TF_CPU_DRIVER_H_
+#define _ARM_TF_CPU_DRIVER_H_
+
+#include <Protocol/MmCommunication.h>
+#include <Protocol/MmConfiguration.h>
+#include <Protocol/MmCpu.h>
+#include <Guid/MpInformation.h>
+
+//
+// CPU driver initialization specific declarations
+//
+extern EFI_MM_SYSTEM_TABLE *mMmst;
+
+//
+// CPU State Save protocol specific declarations
+//
+extern EFI_MM_CPU_PROTOCOL mMmCpuState;
+
+//
+// MM event handling specific declarations
+//
+extern EFI_MM_COMMUNICATE_HEADER    **PerCpuGuidedEventContext;
+extern EFI_MMRAM_DESCRIPTOR          mNsCommBuffer;
+extern MP_INFORMATION_HOB_DATA       *mMpInformationHobData;
+extern EFI_MM_CONFIGURATION_PROTOCOL mMmConfig;
+
+EFI_STATUS
+PiMmStandloneArmTfCpuDriverEntry (
+  IN UINTN EventId,
+  IN UINTN CpuNumber,
+  IN UINTN NsCommBufferAddr
+  );
+
+EFI_STATUS
+EFIAPI
+PiMmCpuTpFwRootMmiHandler (
+  IN     EFI_HANDLE               DispatchHandle,
+  IN     CONST VOID               *Context,        OPTIONAL
+  IN OUT VOID                     *CommBuffer,     OPTIONAL
+  IN OUT UINTN                    *CommBufferSize  OPTIONAL
+  );
+
+EFI_STATUS _PiMmStandloneArmTfCpuDriverEntry (
+  IN UINTN EventId,
+  IN UINTN CpuNumber,
+  IN UINTN NsCommBufferAddr
+  );
+
+#endif