OvmfPkg: Create initial version of PlatformInitLib

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3863

There are 3 variants of PlatformPei in OvmfPkg:
 - OvmfPkg/PlatformPei
 - OvmfPkg/XenPlatformPei
 - OvmfPkg/Bhyve/PlatformPei/PlatformPei.inf
These PlatformPeis can share many common codes, such as
Cmos / Hob / Memory / Platform related functions. This commit
(and its following several patches) are to create a PlatformInitLib
which wraps the common code called in above PlatformPeis.

In this initial version of PlatformInitLib, below Cmos related functions
are introduced:
 - PlatformCmosRead8
 - PlatformCmosWrite8
 - PlatformDebugDumpCmos

They correspond to the functions in OvmfPkg/PlatformPei:
 - CmosRead8
 - CmosWrite8
 - DebugDumpCmos

Considering this PlatformInitLib will be used in SEC phase, global
variables and dynamic PCDs are avoided. We use PlatformInfoHob
to exchange information between functions.

EFI_HOB_PLATFORM_INFO is the data struct which contains the platform
information, such as HostBridgeDevId, BootMode, S3Supported,
SmmSmramRequire, etc.

After PlatformInitLib is created, OvmfPkg/PlatformPei is refactored
with this library.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

OvmfPkg/Library/PlatformInitLib/Cmos.c

@@ -0,0 +1,81 @@
+/** @file
+  PC/AT CMOS access routines
+
+  Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/PlatformInitLib.h>
+#include <Library/DebugLib.h>
+#include "Library/IoLib.h"
+
+/**
+  Reads 8-bits of CMOS data.
+
+  Reads the 8-bits of CMOS data at the location specified by Index.
+  The 8-bit read value is returned.
+
+  @param  Index  The CMOS location to read.
+
+  @return The value read.
+
+**/
+UINT8
+EFIAPI
+PlatformCmosRead8 (
+  IN      UINTN  Index
+  )
+{
+  IoWrite8 (0x70, (UINT8)Index);
+  return IoRead8 (0x71);
+}
+
+/**
+  Writes 8-bits of CMOS data.
+
+  Writes 8-bits of CMOS data to the location specified by Index
+  with the value specified by Value and returns Value.
+
+  @param  Index  The CMOS location to write.
+  @param  Value  The value to write to CMOS.
+
+  @return The value written to CMOS.
+
+**/
+UINT8
+EFIAPI
+PlatformCmosWrite8 (
+  IN      UINTN  Index,
+  IN      UINT8  Value
+  )
+{
+  IoWrite8 (0x70, (UINT8)Index);
+  IoWrite8 (0x71, Value);
+  return Value;
+}
+
+/**
+   Dump the CMOS content
+ */
+VOID
+EFIAPI
+PlatformDebugDumpCmos (
+  VOID
+  )
+{
+  UINT32  Loop;
+
+  DEBUG ((DEBUG_INFO, "CMOS:\n"));
+
+  for (Loop = 0; Loop < 0x80; Loop++) {
+    if ((Loop % 0x10) == 0) {
+      DEBUG ((DEBUG_INFO, "%02x:", Loop));
+    }
+
+    DEBUG ((DEBUG_INFO, " %02x", PlatformCmosRead8 (Loop)));
+    if ((Loop % 0x10) == 0xf) {
+      DEBUG ((DEBUG_INFO, "\n"));
+    }
+  }
+}

OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf

@@ -0,0 +1,36 @@
+## @file
+#  Platform Initialization Lib
+#
+#  This module provides platform specific function to detect boot mode.
+#  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = PlatformInitLib
+  FILE_GUID                      = 89f886b0-7109-46e1-9d28-503ad4ab6ee0
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PlatformInitLib|PEIM
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 EBC
+#
+
+[Sources]
+  Cmos.c
+
+[Packages]
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  IoLib