StandaloneMmPkg: build for 32bit arm machines

This change allows to build StandaloneMmPkg components for 32bit Arm
StandaloneMm firmware.

This change mainly moves AArch64/ source files to Arm/ side directory
for several components:  StandaloneMmCpu, StandaloneMmCoreEntryPoint
and StandaloneMmMemLib. The source file is built for both 32b and 64b
Arm targets.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>

StandaloneMmPkg/Drivers/StandaloneMmCpu/StandaloneMmCpu.h

@@ -0,0 +1,81 @@
+/** @file
+  Private header with declarations and definitions specific to the MM Standalone
+  CPU driver
+
+  Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef _ARM_TF_CPU_DRIVER_H_
+#define _ARM_TF_CPU_DRIVER_H_
+
+#include <Protocol/MmCommunication2.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;
+
+/**
+  The PI Standalone MM entry point for the TF-A CPU driver.
+
+  @param  [in] EventId            The event Id.
+  @param  [in] CpuNumber          The CPU number.
+  @param  [in] NsCommBufferAddr   Address of the NS common buffer.
+
+  @retval   EFI_SUCCESS             Success.
+  @retval   EFI_INVALID_PARAMETER   A parameter was invalid.
+  @retval   EFI_ACCESS_DENIED       Access not permitted.
+  @retval   EFI_OUT_OF_RESOURCES    Out of resources.
+  @retval   EFI_UNSUPPORTED         Operation not supported.
+**/
+EFI_STATUS
+PiMmStandaloneArmTfCpuDriverEntry (
+  IN UINTN EventId,
+  IN UINTN CpuNumber,
+  IN UINTN NsCommBufferAddr
+  );
+
+/**
+  This function is the main entry point for an MM handler dispatch
+  or communicate-based callback.
+
+  @param  DispatchHandle  The unique handle assigned to this handler by
+                          MmiHandlerRegister().
+  @param  Context         Points to an optional handler context which was
+                          specified when the handler was registered.
+  @param  CommBuffer      A pointer to a collection of data in memory that will
+                          be conveyed from a non-MM environment into an
+                          MM environment.
+  @param  CommBufferSize  The size of the CommBuffer.
+
+  @return Status Code
+
+**/
+EFI_STATUS
+EFIAPI
+PiMmCpuTpFwRootMmiHandler (
+  IN     EFI_HANDLE               DispatchHandle,
+  IN     CONST VOID               *Context,        OPTIONAL
+  IN OUT VOID                     *CommBuffer,     OPTIONAL
+  IN OUT UINTN                    *CommBufferSize  OPTIONAL
+  );
+
+#endif