MdeModulePkg/Universal/PCD/Dxe/PcdDxe.uni - edk2 - Git at Google

 // /** @file
 // PCD DXE driver manage database contains all dynamic PCD entries and produce the implementation of PCD protocol.
 //
 // This version PCD DXE depends on the external PCD database binary file, not built in PCD data base.
 // There are two PCD Protocols as follows:
 // 1) PCD_PROTOCOL
 // It is EDKII implementation which support Dynamic/DynamicEx type Pcds.
 // 2) EFI_PCD_PROTOCOL
 // It is defined by PI specification 1.2, Vol 3 which only support dynamicEx
 // type Pcd.
 //
 // For dynamicEx type PCD, it is compatible between PCD_PROTOCOL and EFI_PCD_PROTOCOL.
 // PCD DXE driver will produce above two protocols at same time.
 //
 // PCD database is generated as the separate binary image at build time. The binary image
 // will be intergrated into Firmware volume together with PCD driver.
 //
 // ////////////////////////////////////////////////////////////////////////////////
 // //                                                                            //
 // //                      Introduction of PCD database                          //
 // //                                                                            //
 // ////////////////////////////////////////////////////////////////////////////////
 //
 // 1, Introduction
 // PCD database hold all dynamic type PCD information. The structure of PEI PCD
 // database is generated by build tools according to dynamic PCD usage for
 // specified platform.
 //
 // 2, Dynamic Type PCD
 // Dynamic type PCD is used for the configuration/setting which value is determined
 // dynamic. In contrast, the value of static type PCD (FeatureFlag, FixedPcd,
 // PatchablePcd) is fixed in final generated FD image in build time.
 //
 // 2.1 The "dynamic" determination means one of below cases:
 // a) The PCD setting value is produced by someone driver and consumed by
 // other driver in execution time.
 // b) The PCD setting value is set/get by user from FrontPage.
 // c) The PCD setting value is produced by platform OEM vendor in specified area.
 //
 // 2.2 According to module distribution way, dynamic PCD could be classfied as:
 // a) Dynamic:
 // If module is released in source code and will be built with platform
 // DSC, the dynamic PCD used by this module can be accessed as:
 // PcdGetxx(PcdSampleDynamicPcd);
 // In building platform, build tools will translate PcdSampleDynamicPcd to
 // pair of {Token Space Guid: Token Number} for this PCD.
 // b) DynamicEx:
 // If module is release as binary and will not pariticpate platform building,
 // the dynamic PCD used by this module need be accessed as:
 // PcdGetxxEx(gEfiMyTokenspaceGuid, PcdSampleDynamicPcd)
 // Developer need explicity gives {Token Space Guid:Token Number} as parameter
 // in writting source code.
 //
 // 2.3 According to PCD value's storage method, dynamic PCD could be classfied as:
 // a) Default Storage:
 // - The PCD value is stored in PCD database maintained by PCD driver in boot
 // time memory.
 // - This type is used for communication between PEIM/DXE driver, DXE/DXE
 // driver. But all set/get value will be losted after boot-time memory
 // is turn off.
 // - [PcdsDynamicDefault] is used as section name for this type PCD in
 // platform DSC file. [PcdsDynamicExDefault] is used for dynamicEx type PCD.
 //
 // b) Variable Storage:
 // - The PCD value is stored in variable area.
 // - As default storage type, this type PCD could be used for PEI/DXE driver
 // communication. But beside it, this type PCD could also be used to store
 // the value associate with a HII setting via variable interface.
 // - In PEI phase, the PCD value could only be got but can not be set due
 // to variable area is readonly.
 // - [PcdsDynamicHii] is used as section name for this type PCD in platform
 // DSC file. [PcdsDynamicExHii] is for dynamicEx type PCD.
 //
 // c) OEM specificed storage area:
 // - The PCD value is stored in OEM specified area which base address is
 // specified by a FixedAtBuild PCD setting - PcdVpdBaseAddress.
 // - The area is read only for PEI and DXE phase.
 // - [PcdsDynamicVpd] is used as section name for this type PCD in platform
 // DSC file. [PcdsDynamicExVpd] is for dynamicex type PCD.
 //
 // 2.4 When and how to use dynamic PCD
 // Module developer do not care the used PCD is dynamic or static when writting
 // source code/INF. Dynamic PCD and dynamic type is pointed by platform integrator
 // in platform DSC file. Please ref section 2.3 to get matching between dynamic
 // PCD type and section name in DSC file.
 //
 // 3, PCD database:
 // Although dynamic PCD could be in different storage type as above description,
 // but the basic information and default value for all dynamic PCD is hold
 // by PCD database maintained by PEI/DXE driver.
 //
 // As the whole EFI BIOS boot path is divided into PEI/DXE phase, the PCD database
 // also is divided into Pei/Dxe database maintaied by PcdPeim/PcdDxe driver separatly.
 // To make PcdPeim's driver image smaller, PEI PCD database only hold all dynamic
 // PCD information used in PEI phase or use in both PEI/DXE phase. And DXE PCD
 // database contains all PCDs used in PEI/DXE phase in memory.
 //
 // Build tool will generate PCD database into the separate binary file for
 // PEI/DXE PCD driver according to dynamic PCD section in platform DSC file.
 //
 // 3.1 PcdPeim and PcdDxe
 // PEI PCD database is maintained by PcdPeim driver run from flash. PcdPeim driver
 // build guid hob in temporary memory and copy the binary data base from flash
 // to temporary memory for PEI PCD database.
 // DXE PCD database is maintained by PcdDxe driver.At entry point of PcdDxe driver,
 // a new PCD database is allocated in boot-time memory which including all
 // PEI PCD and DXE PCD entry.
 //
 // Pcd driver should run as early as possible before any other driver access
 // dynamic PCD's value. PEI/DXE "Apriori File" mechanism make it possible by
 // making PcdPeim/PcdDxe as first dispatching driver in PEI/DXE phase.
 //
 // 3.2 Token space Guid/Token number, Platform token, Local token number
 // Dynamic PCD
 // +-----------+               +---------+
 // |TokenSpace |               |Platform |
 // |   Guid    |  build tool   | Token   |
 // |    +      +-------------->| Number  |
 // |  Token    |               +---------+`._
 // |  Number   |                             `.
 // +-----------+                               `.  +------+
 // `-|Local |
 // |Token |
 // DynamicEx PCD            ,-|Number|
 // +-----------+         ,-'  +------+
 // |TokenSpace |      ,-'
 // |   Guid    |  _,-'
 // |    +      +.'
 // |  Token    |
 // |  Number   |
 // +-----------+
 //
 //
 // 3.2.1 Pair of Token space guid + Token number
 // Any type PCD is identified by pair of "TokenSpaceGuid + TokeNumber". But it
 // is not easy maintained by PCD driver, and hashed token number will make
 // searching slowly.
 //
 // 3.2.2 Platform Token Number
 // "Platform token number" concept is introduced for mapping to a pair of
 // "TokenSpaceGuid + TokenNumber". The platform token number is generated by
 // build tool in autogen.h and all of them are continual in a platform scope
 // started from 1.(0 meaning invalid internal token number)
 // With auto-generated "platform token number", PcdGet(PcdSampleDynamicPcd)
 // in source code is translated to LibPcdGet(_PCD_TOKEN_PcdSampleDynamicPcd)
 // in autogen.h.
 // Notes: The mapping between pair of "tokenspace guid + token number" and
 // "internal token number" need build tool establish, so "platform token number"
 // mechanism is not suitable for binary module which use DynamicEx type PCD.
 // To access a dynamicEx type PCD, pair of "token space guid/token number" all need
 // to be specificed for PcdSet/PcdGet accessing macro.
 //
 // Platform Token Number is started from 1, and inceased continuous. From whole
 // platform scope, there are two zones: PEI Zone and DXE Zone
 // |                      Platform Token Number
 // ----------|----------------------------------------------------------------
 // PEI Zone: |            1                 ~  PEI_LOCAL_TOKEN_NUMBER
 // DXE Zone: | (PEI_LOCAL_TOKEN_NUMBER + 1) ~ (PEI_LOCAL_TOKEN_NUMBER + DXE_LOCAL_TOKEN_NUMBER)
 //
 // 3.2.3 Local Token Number
 // To fast searching a PCD entry in PCD database, PCD driver translate
 // platform token number to local token number via a mapping table.
 // For binary DynamicEx type PCD, there is a another mapping table to translate
 // "token space guid + token number" to local token number directly.
 // Local token number is identifier for all internal interface in PCD PEI/DXE
 // driver.
 //
 // A local token number is a 32-bit value in following meaning:
 // 32 ------------- 28 ---------- 24 -------- 0
 // | PCD type mask  | Datum Type  |  Offset  |
 // +-----------------------------------------+
 // where:
 // PCd type mask: indicate Pcd type from following macro:
 // PCD_TYPE_DATA
 // PCD_TYPE_HII
 // PCD_TYPE_VPD
 // PCD_TYPE_SKU_ENABLED
 // PCD_TYPE_STRING
 // Datum Type   : indicate PCD vaue type from following macro:
 // PCD_DATUM_TYPE_POINTER
 // PCD_DATUM_TYPE_UINT8
 // PCD_DATUM_TYPE_UINT16
 // PCD_DATUM_TYPE_UINT32
 // PCD_DATUM_TYPE_UINT64
 // Offset      : indicate the related offset of PCD value in PCD database array.
 // Based on local token number, PCD driver could fast determine PCD type, value
 // type and get PCD entry from PCD database.
 //
 // 3.3 PCD Database binary file
 // PCD Database binary file will be created at build time as the standalone binary image.
 // To understand the binary image layout, PCD Database C structure is still generated
 // as comments by build tools in PCD driver's autogen.h/
 // autogen.c file. In generated C structure, following information is stored:
 // - ExMapTable: This table is used translate a binary dynamicex type PCD's
 // "tokenguid + token" to local token number.
 // - LocalTokenNumberTable:
 // This table stores all local token number in array, use "Internal
 // token number" as array index to get PCD entry's offset fastly.
 // - SizeTable:  This table stores the size information for all PCD entry.
 // - GuidTable:  This table stores guid value for DynamicEx's token space,
 // HII type PCD's variable GUID.
 // - SkuIdTable: TBD
 // - SystemSkuId: TBD
 // - PCD value structure:
 // Every PCD has a value record in PCD database. For different
 // datum type PCD has different record structure which will be
 // introduced in 3.3.1
 //
 // In a PCD database structure, there are two major area: Init and UnInit.
 // Init area is use stored above PCD internal structure such as ExMapTable,
 // LocalTokenNumberTable etc and the (default) value of PCD which has default
 // value specified in platform DSC file.
 // Unint area is used stored the value of PCD which has no default value in
 // platform DSC file, the value of NULL, 0 specified in platform DSC file can
 // be seemed as "no default value".
 //
 // 3.3.1 Simple Sample PCD Database C Structure
 // A general sample of PCD database structue is as follows:
 // typedef struct _PCD_DATABASE {
 // typedef struct _PCD_DATABASE_INIT {
 // //===== Following is PCD database internal maintain structures
 // DYNAMICEX_MAPPING ExMapTable[PEI_EXMAPPING_TABLE_SIZE];
 // UINT32            LocalTokenNumberTable[PEI_LOCAL_TOKEN_NUMBER_TABLE_SIZE];
 // GUID              GuidTable[PEI_GUID_TABLE_SIZE];
 // SIZE_INFO         SizeTable[PEI_SIZE_TABLE_SIZE];
 // UINT8             SkuIdTable[PEI_SKUID_TABLE_SIZE];
 // SKU_ID            SystemSkuId;
 //
 // //===== Following is value structure for PCD with default value
 // ....
 // ....
 // ....
 // } Init;
 // typedef struct _PCD_DATABSE_UNINIT {
 // //==== Following is value structure for PCD without default value
 // ....
 // ....
 // } UnInit;
 // }
 //
 // 3.3.2 PCD value structure in PCD database C structure
 // The value's structure is generated by build tool in PCD database C structure.
 // The PCDs in different datum type has different value structure.
 //
 // 3.3.2.1 UINT8/UINT16/UINT32/UINT64 datum type PCD
 // The C structure for these datum type PCD is just a UINT8/UINT16/UINT32/UINT64
 // data member in PCD database, For example:
 // UINT16  PcdHardwareErrorRecordLevel_d3705011_bc19_4af7_be16_f68030378c15_VariableDefault_0;
 // Above structure is generated by build tool, the member name is "PcdCName_Guidvalue"
 // Member type is UINT16 according to PcdHardwareErrorRecordLevel declaration
 // in DEC file.
 //
 // 3.3.2.2 VOID* datum type PCD
 // The value of VOID* datum type PCD is a UINT8/UINT16 array in PCD database.
 //
 // 3.3.2.2.1 VOID* - string type
 // If the default value for VOID* datum type PCD like L"xxx", the PCD is
 // used for unicode string, and C structure of this datum type PCD is
 // UINT16 string array in PCD database, for example:
 // UINT16 StringTable[29];
 // The number of 29 in above sample is max size of a unicode string.
 //
 // If the default value for VOID* datum type PCD like "xxx", the PCD is
 // used for ascii string, and C structure of this datum type PCD is
 // UINT8 string array in PCD database, for example:
 // UINT8 StringTable[20];
 // The number of 20 in above sample is max size of a ascii string.
 //
 // 3.3.2.2.2 VOID* - byte array
 // If the default value of VOID* datum type PCD like {'0x29', '0x01', '0xf2'}
 // the PCD is used for byte array. The generated structrue is same as
 // above ascii string table,
 // UINT8 StringTable[13];
 // The number of 13 in above sample is max size of byte array.
 //
 // 3.3.3 Some utility structures in PCD Database
 // 3.3.3.1 GuidTable
 // GuidTable array is used to store all related GUID value in PCD database:
 // - Variable GUID for HII type PCD
 // - Token space GUID for dynamicex type PCD
 //
 // Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
 //
 // 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.
 //
 // **/


 #string STR_MODULE_ABSTRACT             #language en-US "PCD DXE driver manages the database that contains all dynamic PCD entries and produce the implementation of PCD protocol"

 #string STR_MODULE_DESCRIPTION          #language en-US "PCD DXE driver manages the database that contains all dynamic PCD entries and produces the implementation of PCD protocol."
	// /** @file
	// PCD DXE driver manage database contains all dynamic PCD entries and produce the implementation of PCD protocol.
	//
	// This version PCD DXE depends on the external PCD database binary file, not built in PCD data base.
	// There are two PCD Protocols as follows:
	// 1) PCD_PROTOCOL
	// It is EDKII implementation which support Dynamic/DynamicEx type Pcds.
	// 2) EFI_PCD_PROTOCOL
	// It is defined by PI specification 1.2, Vol 3 which only support dynamicEx
	// type Pcd.
	//
	// For dynamicEx type PCD, it is compatible between PCD_PROTOCOL and EFI_PCD_PROTOCOL.
	// PCD DXE driver will produce above two protocols at same time.
	//
	// PCD database is generated as the separate binary image at build time. The binary image
	// will be intergrated into Firmware volume together with PCD driver.
	//
	// ////////////////////////////////////////////////////////////////////////////////
	// // //
	// // Introduction of PCD database //
	// // //
	// ////////////////////////////////////////////////////////////////////////////////
	//
	// 1, Introduction
	// PCD database hold all dynamic type PCD information. The structure of PEI PCD
	// database is generated by build tools according to dynamic PCD usage for
	// specified platform.
	//
	// 2, Dynamic Type PCD
	// Dynamic type PCD is used for the configuration/setting which value is determined
	// dynamic. In contrast, the value of static type PCD (FeatureFlag, FixedPcd,
	// PatchablePcd) is fixed in final generated FD image in build time.
	//
	// 2.1 The "dynamic" determination means one of below cases:
	// a) The PCD setting value is produced by someone driver and consumed by
	// other driver in execution time.
	// b) The PCD setting value is set/get by user from FrontPage.
	// c) The PCD setting value is produced by platform OEM vendor in specified area.
	//
	// 2.2 According to module distribution way, dynamic PCD could be classfied as:
	// a) Dynamic:
	// If module is released in source code and will be built with platform
	// DSC, the dynamic PCD used by this module can be accessed as:
	// PcdGetxx(PcdSampleDynamicPcd);
	// In building platform, build tools will translate PcdSampleDynamicPcd to
	// pair of {Token Space Guid: Token Number} for this PCD.
	// b) DynamicEx:
	// If module is release as binary and will not pariticpate platform building,
	// the dynamic PCD used by this module need be accessed as:
	// PcdGetxxEx(gEfiMyTokenspaceGuid, PcdSampleDynamicPcd)
	// Developer need explicity gives {Token Space Guid:Token Number} as parameter
	// in writting source code.
	//
	// 2.3 According to PCD value's storage method, dynamic PCD could be classfied as:
	// a) Default Storage:
	// - The PCD value is stored in PCD database maintained by PCD driver in boot
	// time memory.
	// - This type is used for communication between PEIM/DXE driver, DXE/DXE
	// driver. But all set/get value will be losted after boot-time memory
	// is turn off.
	// - [PcdsDynamicDefault] is used as section name for this type PCD in
	// platform DSC file. [PcdsDynamicExDefault] is used for dynamicEx type PCD.
	//
	// b) Variable Storage:
	// - The PCD value is stored in variable area.
	// - As default storage type, this type PCD could be used for PEI/DXE driver
	// communication. But beside it, this type PCD could also be used to store
	// the value associate with a HII setting via variable interface.
	// - In PEI phase, the PCD value could only be got but can not be set due
	// to variable area is readonly.
	// - [PcdsDynamicHii] is used as section name for this type PCD in platform
	// DSC file. [PcdsDynamicExHii] is for dynamicEx type PCD.
	//
	// c) OEM specificed storage area:
	// - The PCD value is stored in OEM specified area which base address is
	// specified by a FixedAtBuild PCD setting - PcdVpdBaseAddress.
	// - The area is read only for PEI and DXE phase.
	// - [PcdsDynamicVpd] is used as section name for this type PCD in platform
	// DSC file. [PcdsDynamicExVpd] is for dynamicex type PCD.
	//
	// 2.4 When and how to use dynamic PCD
	// Module developer do not care the used PCD is dynamic or static when writting
	// source code/INF. Dynamic PCD and dynamic type is pointed by platform integrator
	// in platform DSC file. Please ref section 2.3 to get matching between dynamic
	// PCD type and section name in DSC file.
	//
	// 3, PCD database:
	// Although dynamic PCD could be in different storage type as above description,
	// but the basic information and default value for all dynamic PCD is hold
	// by PCD database maintained by PEI/DXE driver.
	//
	// As the whole EFI BIOS boot path is divided into PEI/DXE phase, the PCD database
	// also is divided into Pei/Dxe database maintaied by PcdPeim/PcdDxe driver separatly.
	// To make PcdPeim's driver image smaller, PEI PCD database only hold all dynamic
	// PCD information used in PEI phase or use in both PEI/DXE phase. And DXE PCD
	// database contains all PCDs used in PEI/DXE phase in memory.
	//
	// Build tool will generate PCD database into the separate binary file for
	// PEI/DXE PCD driver according to dynamic PCD section in platform DSC file.
	//
	// 3.1 PcdPeim and PcdDxe
	// PEI PCD database is maintained by PcdPeim driver run from flash. PcdPeim driver
	// build guid hob in temporary memory and copy the binary data base from flash
	// to temporary memory for PEI PCD database.
	// DXE PCD database is maintained by PcdDxe driver.At entry point of PcdDxe driver,
	// a new PCD database is allocated in boot-time memory which including all
	// PEI PCD and DXE PCD entry.
	//
	// Pcd driver should run as early as possible before any other driver access
	// dynamic PCD's value. PEI/DXE "Apriori File" mechanism make it possible by
	// making PcdPeim/PcdDxe as first dispatching driver in PEI/DXE phase.
	//
	// 3.2 Token space Guid/Token number, Platform token, Local token number
	// Dynamic PCD
	// +-----------+ +---------+
	// \|TokenSpace \| \|Platform \|
	// \| Guid \| build tool \| Token \|
	// \| + +-------------->\| Number \|
	// \| Token \| +---------+`._
	// \| Number \| `.
	// +-----------+ `. +------+
	// `-\|Local \|
	// \|Token \|
	// DynamicEx PCD ,-\|Number\|
	// +-----------+ ,-' +------+
	// \|TokenSpace \| ,-'
	// \| Guid \| _,-'
	// \| + +.'
	// \| Token \|
	// \| Number \|
	// +-----------+
	//
	//
	// 3.2.1 Pair of Token space guid + Token number
	// Any type PCD is identified by pair of "TokenSpaceGuid + TokeNumber". But it
	// is not easy maintained by PCD driver, and hashed token number will make
	// searching slowly.
	//
	// 3.2.2 Platform Token Number
	// "Platform token number" concept is introduced for mapping to a pair of
	// "TokenSpaceGuid + TokenNumber". The platform token number is generated by
	// build tool in autogen.h and all of them are continual in a platform scope
	// started from 1.(0 meaning invalid internal token number)
	// With auto-generated "platform token number", PcdGet(PcdSampleDynamicPcd)
	// in source code is translated to LibPcdGet(_PCD_TOKEN_PcdSampleDynamicPcd)
	// in autogen.h.
	// Notes: The mapping between pair of "tokenspace guid + token number" and
	// "internal token number" need build tool establish, so "platform token number"
	// mechanism is not suitable for binary module which use DynamicEx type PCD.
	// To access a dynamicEx type PCD, pair of "token space guid/token number" all need
	// to be specificed for PcdSet/PcdGet accessing macro.
	//
	// Platform Token Number is started from 1, and inceased continuous. From whole
	// platform scope, there are two zones: PEI Zone and DXE Zone
	// \| Platform Token Number
	// ----------\|----------------------------------------------------------------
	// PEI Zone: \| 1 ~ PEI_LOCAL_TOKEN_NUMBER
	// DXE Zone: \| (PEI_LOCAL_TOKEN_NUMBER + 1) ~ (PEI_LOCAL_TOKEN_NUMBER + DXE_LOCAL_TOKEN_NUMBER)
	//
	// 3.2.3 Local Token Number
	// To fast searching a PCD entry in PCD database, PCD driver translate
	// platform token number to local token number via a mapping table.
	// For binary DynamicEx type PCD, there is a another mapping table to translate
	// "token space guid + token number" to local token number directly.
	// Local token number is identifier for all internal interface in PCD PEI/DXE
	// driver.
	//
	// A local token number is a 32-bit value in following meaning:
	// 32 ------------- 28 ---------- 24 -------- 0
	// \| PCD type mask \| Datum Type \| Offset \|
	// +-----------------------------------------+
	// where:
	// PCd type mask: indicate Pcd type from following macro:
	// PCD_TYPE_DATA
	// PCD_TYPE_HII
	// PCD_TYPE_VPD
	// PCD_TYPE_SKU_ENABLED
	// PCD_TYPE_STRING
	// Datum Type : indicate PCD vaue type from following macro:
	// PCD_DATUM_TYPE_POINTER
	// PCD_DATUM_TYPE_UINT8
	// PCD_DATUM_TYPE_UINT16
	// PCD_DATUM_TYPE_UINT32
	// PCD_DATUM_TYPE_UINT64
	// Offset : indicate the related offset of PCD value in PCD database array.
	// Based on local token number, PCD driver could fast determine PCD type, value
	// type and get PCD entry from PCD database.
	//
	// 3.3 PCD Database binary file
	// PCD Database binary file will be created at build time as the standalone binary image.
	// To understand the binary image layout, PCD Database C structure is still generated
	// as comments by build tools in PCD driver's autogen.h/
	// autogen.c file. In generated C structure, following information is stored:
	// - ExMapTable: This table is used translate a binary dynamicex type PCD's
	// "tokenguid + token" to local token number.
	// - LocalTokenNumberTable:
	// This table stores all local token number in array, use "Internal
	// token number" as array index to get PCD entry's offset fastly.
	// - SizeTable: This table stores the size information for all PCD entry.
	// - GuidTable: This table stores guid value for DynamicEx's token space,
	// HII type PCD's variable GUID.
	// - SkuIdTable: TBD
	// - SystemSkuId: TBD
	// - PCD value structure:
	// Every PCD has a value record in PCD database. For different
	// datum type PCD has different record structure which will be
	// introduced in 3.3.1
	//
	// In a PCD database structure, there are two major area: Init and UnInit.
	// Init area is use stored above PCD internal structure such as ExMapTable,
	// LocalTokenNumberTable etc and the (default) value of PCD which has default
	// value specified in platform DSC file.
	// Unint area is used stored the value of PCD which has no default value in
	// platform DSC file, the value of NULL, 0 specified in platform DSC file can
	// be seemed as "no default value".
	//
	// 3.3.1 Simple Sample PCD Database C Structure
	// A general sample of PCD database structue is as follows:
	// typedef struct _PCD_DATABASE {
	// typedef struct _PCD_DATABASE_INIT {
	// //===== Following is PCD database internal maintain structures
	// DYNAMICEX_MAPPING ExMapTable[PEI_EXMAPPING_TABLE_SIZE];
	// UINT32 LocalTokenNumberTable[PEI_LOCAL_TOKEN_NUMBER_TABLE_SIZE];
	// GUID GuidTable[PEI_GUID_TABLE_SIZE];
	// SIZE_INFO SizeTable[PEI_SIZE_TABLE_SIZE];
	// UINT8 SkuIdTable[PEI_SKUID_TABLE_SIZE];
	// SKU_ID SystemSkuId;
	//
	// //===== Following is value structure for PCD with default value
	// ....
	// ....
	// ....
	// } Init;
	// typedef struct _PCD_DATABSE_UNINIT {
	// //==== Following is value structure for PCD without default value
	// ....
	// ....
	// } UnInit;
	// }
	//
	// 3.3.2 PCD value structure in PCD database C structure
	// The value's structure is generated by build tool in PCD database C structure.
	// The PCDs in different datum type has different value structure.
	//
	// 3.3.2.1 UINT8/UINT16/UINT32/UINT64 datum type PCD
	// The C structure for these datum type PCD is just a UINT8/UINT16/UINT32/UINT64
	// data member in PCD database, For example:
	// UINT16 PcdHardwareErrorRecordLevel_d3705011_bc19_4af7_be16_f68030378c15_VariableDefault_0;
	// Above structure is generated by build tool, the member name is "PcdCName_Guidvalue"
	// Member type is UINT16 according to PcdHardwareErrorRecordLevel declaration
	// in DEC file.
	//
	// 3.3.2.2 VOID* datum type PCD
	// The value of VOID* datum type PCD is a UINT8/UINT16 array in PCD database.
	//
	// 3.3.2.2.1 VOID* - string type
	// If the default value for VOID* datum type PCD like L"xxx", the PCD is
	// used for unicode string, and C structure of this datum type PCD is
	// UINT16 string array in PCD database, for example:
	// UINT16 StringTable[29];
	// The number of 29 in above sample is max size of a unicode string.
	//
	// If the default value for VOID* datum type PCD like "xxx", the PCD is
	// used for ascii string, and C structure of this datum type PCD is
	// UINT8 string array in PCD database, for example:
	// UINT8 StringTable[20];
	// The number of 20 in above sample is max size of a ascii string.
	//
	// 3.3.2.2.2 VOID* - byte array
	// If the default value of VOID* datum type PCD like {'0x29', '0x01', '0xf2'}
	// the PCD is used for byte array. The generated structrue is same as
	// above ascii string table,
	// UINT8 StringTable[13];
	// The number of 13 in above sample is max size of byte array.
	//
	// 3.3.3 Some utility structures in PCD Database
	// 3.3.3.1 GuidTable
	// GuidTable array is used to store all related GUID value in PCD database:
	// - Variable GUID for HII type PCD
	// - Token space GUID for dynamicex type PCD
	//
	// Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
	//
	// 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.
	//
	// **/


	#string STR_MODULE_ABSTRACT #language en-US "PCD DXE driver manages the database that contains all dynamic PCD entries and produce the implementation of PCD protocol"

	#string STR_MODULE_DESCRIPTION #language en-US "PCD DXE driver manages the database that contains all dynamic PCD entries and produces the implementation of PCD protocol."