PCD/Dxe/Pcd.inf

## @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 - 2015, 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.

#

#

##


[Defines]
  INF_VERSION                    = 0x00010005
  BASE_NAME                      = PcdDxe
  MODULE_UNI_FILE                = PcdDxe.uni
  FILE_GUID                      = 80CF7257-87AB-47f9-A3FE-D50B76D89541
  MODULE_TYPE                    = DXE_DRIVER
  VERSION_STRING                 = 4.0
  PCD_IS_DRIVER                  = DXE_PCD_DRIVER
  ENTRY_POINT                    = PcdDxeInit

#

# The following information is for reference only and not required by the build tools.

#

#  VALID_ARCHITECTURES           = IA32 X64 IPF EBC

#


[Sources]
  Pcd.c
  Service.c
  Service.h

[Packages]
  MdePkg/MdePkg.dec
  MdeModulePkg/MdeModulePkg.dec

[LibraryClasses]
  UefiRuntimeServicesTableLib
  BaseMemoryLib
  UefiBootServicesTableLib
  MemoryAllocationLib
  HobLib
  UefiDriverEntryPoint
  UefiLib
  DebugLib
  BaseLib
  PcdLib
  DxeServicesLib

[Guids]
  gPcdDataBaseHobGuid                           ## SOMETIMES_CONSUMES  ## HOB

  gPcdDataBaseSignatureGuid                     ## CONSUMES  ## GUID  # PCD database signature GUID.


[Protocols]
  gPcdProtocolGuid                              ## PRODUCES

  gEfiPcdProtocolGuid                           ## PRODUCES

  gGetPcdInfoProtocolGuid                       ## SOMETIMES_PRODUCES

  gEfiGetPcdInfoProtocolGuid                    ## SOMETIMES_PRODUCES

  ## NOTIFY

  ## SOMETIMES_CONSUMES

  gEdkiiVariableLockProtocolGuid

[Pcd]
  gEfiMdeModulePkgTokenSpaceGuid.PcdVpdBaseAddress  ## SOMETIMES_CONSUMES


[Depex]
  TRUE

[UserExtensions.TianoCore."ExtraFiles"]
  PcdDxeExtra.uni