## @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