[PATCH v2 1/8] MdeModulePkg: Add Variable Flash Info HOB

["Michael Kubacki" <mikuback@linux.microsoft.com>]

From: Michael Kubacki <michael.kubacki@microsoft.com>

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3479

Adds a new GUID that is used to identify a HOB that passes variable
flash information to UEFI variable drivers in HOB consumption phases
such as DXE, Traditional MM, and Standalone MM.

This information was previously passed directly with PCDs such
as EfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
and gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize.

However, the Standalone MM variable driver instance does not have
direct access to the PCD database. Therefore, this HOB will first
be considered as the source for variable flash information and
if platforms do not produce the HOB, reading the information from
the PCDs directly will be a backup to provide backward
compatibility.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
---
 MdeModulePkg/Include/Guid/VariableFlashInfo.h | 39 ++++++++++++++++++++
 MdeModulePkg/MdeModulePkg.dec                 |  4 ++
 2 files changed, 43 insertions(+)

diff --git a/MdeModulePkg/Include/Guid/VariableFlashInfo.h b/MdeModulePkg/Include/Guid/VariableFlashInfo.h
new file mode 100644
index 000000000000..e526e362aab9
--- /dev/null
+++ b/MdeModulePkg/Include/Guid/VariableFlashInfo.h
@@ -0,0 +1,39 @@
+/** @file
+  This file defines the GUID and data structure used to pass information about
+  a variable store mapped on flash (i.e. a MMIO firmware volume) to the DXE and MM environment.
+
+  Copyright (c) Microsoft Corporation.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef VARIABLE_FLASH_INFO_H_
+#define VARIABLE_FLASH_INFO_H_
+
+#define VARIABLE_FLASH_INFO_HOB_GUID \
+  { 0x5d11c653, 0x8154, 0x4ac3, { 0xa8, 0xc2, 0xfb, 0xa2, 0x89, 0x20, 0xfc, 0x90 }}
+
+#define VARIABLE_FLASH_INFO_HOB_VERSION  1
+
+extern EFI_GUID  gVariableFlashInfoHobGuid;
+
+#pragma pack (push, 1)
+
+///
+/// This structure can be used to describe UEFI variable
+/// flash information.
+///
+typedef struct {
+  UINT32                  Version;
+  EFI_PHYSICAL_ADDRESS    NvStorageBaseAddress;
+  UINT64                  NvStorageLength;
+  EFI_PHYSICAL_ADDRESS    FtwSpareBaseAddress;
+  UINT64                  FtwSpareLength;
+  EFI_PHYSICAL_ADDRESS    FtwWorkingBaseAddress;
+  UINT64                  FtwWorkingLength;
+} VARIABLE_FLASH_INFO;
+
+#pragma pack (pop)
+
+#endif
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index cf79292ec877..4e82f5836096 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -226,6 +226,10 @@ [Guids]
   #  Include/Guid/SmmVariableCommon.h
   gSmmVariableWriteGuid  = { 0x93ba1826, 0xdffb, 0x45dd, { 0x82, 0xa7, 0xe7, 0xdc, 0xaa, 0x3b, 0xbd, 0xf3 }}
 
+  ## Guid of the variable flash information HOB.
+  #  Include/Guid/VariableFlashInfo.h
+  gVariableFlashInfoHobGuid = { 0x5d11c653, 0x8154, 0x4ac3, { 0xa8, 0xc2, 0xfb, 0xa2, 0x89, 0x20, 0xfc, 0x90 }}
+
   ## Performance protocol guid that also acts as the performance HOB guid and performance variable GUID
   #  Include/Guid/Performance.h
   gPerformanceProtocolGuid       = { 0x76B6BDFA, 0x2ACD, 0x4462, { 0x9E, 0x3F, 0xCB, 0x58, 0xC9, 0x69, 0xD9, 0x37 } }
-- 
2.28.0.windows.1