[edk2-devel][edk2-platforms][PATCH V1 1/1] MinPlatformPkg/Variable*Lib: Build VariableRead and VariableWrite libs

["Oram, Isaac W" <isaac.w.oram@intel.com>]

Add the VariableReadLib and VariableWriteLib instances to Components to
ensure build when building MinPlatformPkg.dsc.
Add a NULL library instance that provides the non-functional library
instance for VariableReadLib designed for all phase use.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Eric Dong <eric.dong@intel.com>
Signed-off-by: Isaac Oram <isaac.w.oram@intel.com>
---
 Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.c   | 75 ++++++++++++++++++++
 Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf | 37 ++++++++++
 Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc                                          |  6 +-
 3 files changed, 117 insertions(+), 1 deletion(-)

diff --git a/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.c b/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.c
new file mode 100644
index 0000000000..f276b7b6b4
--- /dev/null
+++ b/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.c
@@ -0,0 +1,75 @@
+/** @file
+  NULL implementation of Variable Read Lib
+
+  This library provides phase agnostic access to the UEFI Variable Services.
+  This is done by implementing a wrapper on top of the phase specific mechanism
+  for reading from UEFI variables. For example, the PEI implementation of this
+  library uses EFI_PEI_READ_ONLY_VARIABLE2_PPI. The DXE implementation accesses
+  the UEFI Runtime Services Table, and the SMM implementation uses
+  EFI_SMM_VARIABLE_PROTOCOL.
+
+  Using this library allows code to be written in a generic manner that can be
+  used in PEI, DXE, or SMM without modification.
+
+  @copyright
+  Copyright 2021 Intel Corporation. <BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Uefi/UefiBaseType.h>
+
+/**
+  Returns the value of a variable.
+
+  @param[in]       VariableName  A Null-terminated string that is the name of the vendor's
+                                 variable.
+  @param[in]       VendorGuid    A unique identifier for the vendor.
+  @param[out]      Attributes    If not NULL, a pointer to the memory location to return the
+                                 attributes bitmask for the variable.
+  @param[in, out]  DataSize      On input, the size in bytes of the return Data buffer.
+                                 On output the size of data returned in Data.
+  @param[out]      Data          The buffer to return the contents of the variable. May be NULL
+                                 with a zero DataSize in order to determine the size buffer needed.
+
+  @retval EFI_UNSUPPORTED        This function is not implemented by this instance of the LibraryClass
+
+**/
+EFI_STATUS
+EFIAPI
+VarLibGetVariable (
+  IN     CHAR16                      *VariableName,
+  IN     EFI_GUID                    *VendorGuid,
+  OUT    UINT32                      *Attributes,    OPTIONAL
+  IN OUT UINTN                       *DataSize,
+  OUT    VOID                        *Data           OPTIONAL
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Enumerates the current variable names.
+
+  @param[in, out]  VariableNameSize The size of the VariableName buffer. The size must be large
+                                    enough to fit input string supplied in VariableName buffer.
+  @param[in, out]  VariableName     On input, supplies the last VariableName that was returned
+                                    by GetNextVariableName(). On output, returns the Nullterminated
+                                    string of the current variable.
+  @param[in, out]  VendorGuid       On input, supplies the last VendorGuid that was returned by
+                                    GetNextVariableName(). On output, returns the
+                                    VendorGuid of the current variable.
+
+  @retval EFI_UNSUPPORTED           This function is not implemented by this instance of the LibraryClass
+
+**/
+EFI_STATUS
+EFIAPI
+VarLibGetNextVariableName (
+  IN OUT UINTN                    *VariableNameSize,
+  IN OUT CHAR16                   *VariableName,
+  IN OUT EFI_GUID                 *VendorGuid
+  )
+{
+  return EFI_UNSUPPORTED;
+}
diff --git a/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf b/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf
new file mode 100644
index 0000000000..3a397998a9
--- /dev/null
+++ b/Platform/Intel/MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf
@@ -0,0 +1,37 @@
+## @file
+# Component description file for NULL implementation of Variable Read Lib
+#
+# This library provides phase agnostic access to the UEFI Variable Services.
+# This is done by implementing a wrapper on top of the phase specific mechanism
+# for reading from UEFI variables. For example, the PEI implementation of this
+# library uses EFI_PEI_READ_ONLY_VARIABLE2_PPI. The DXE implementation accesses
+# the UEFI Runtime Services Table, and the SMM implementation uses
+# EFI_SMM_VARIABLE_PROTOCOL.
+#
+# Using this library allows code to be written in a generic manner that can be
+# used in PEI, DXE, or SMM without modification.
+#
+# @copyright
+# Copyright 2021 Intel Corporation. <BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+##
+## NOTICE: This library is also available in MinPlatformPkg. This copy was added
+##         for the convience of those that are using an older MinPlatformPkg.
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = BaseVariableReadLibNull
+  FILE_GUID                      = 5C9E2489-329F-4D2A-90F1-F5CB2A88A3E6
+  VERSION_STRING                 = 1.0
+  MODULE_TYPE                    = BASE
+  LIBRARY_CLASS                  = VariableReadLib
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[Sources]
+  BaseVariableReadLibNull.c
diff --git a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
index 07b776cecd..a09f8db3ab 100644
--- a/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
+++ b/Platform/Intel/MinPlatformPkg/MinPlatformPkg.dsc
@@ -74,7 +74,7 @@
   FspWrapperApiTestLib|IntelFsp2WrapperPkg/Library/PeiFspWrapperApiTestLib/PeiFspWrapperApiTestLib.inf
   FspWrapperHobProcessLib|MinPlatformPkg/FspWrapper/Library/PeiFspWrapperHobProcessLib/PeiFspWrapperHobProcessLib.inf
   PlatformSecLib|MinPlatformPkg/FspWrapper/Library/SecFspWrapperPlatformSecLib/SecFspWrapperPlatformSecLib.inf
-
+  VariableReadLib|MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf
   FspWrapperPlatformLib|MinPlatformPkg/FspWrapper/Library/PeiFspWrapperPlatformLib/PeiFspWrapperPlatformLib.inf
 
   BoardInitLib|MinPlatformPkg/PlatformInit/Library/BoardInitLibNull/BoardInitLibNull.inf
@@ -214,5 +214,9 @@
   MinPlatformPkg/Tcg/Tcg2PlatformPei/Tcg2PlatformPei.inf
   MinPlatformPkg/Tcg/Tcg2PlatformDxe/Tcg2PlatformDxe.inf
 
+  MinPlatformPkg/Library/BaseVariableReadLibNull/BaseVariableReadLibNull.inf
+  MinPlatformPkg/Library/SmmVariableReadLib/StandaloneMmVariableReadLib.inf
+  MinPlatformPkg/Library/SmmVariableWriteLib/StandaloneMmVariableWriteLib.inf
+
 [BuildOptions]
   *_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES
-- 
2.27.0.windows.1