diff options
| author | klu2 <klu2@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-04-01 06:43:16 +0000 |
|---|---|---|
| committer | klu2 <klu2@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-04-01 06:43:16 +0000 |
| commit | b6b3dc4410d0abbda01c76674b18f9c19e8edd9d (patch) | |
| tree | a3ae8f5b76702aab5c7f75dbbe6a75a5218a1980 /MdeModulePkg/Universal/PCD/Pei | |
| parent | 62c236c065720ee4ac7d9832aa806cd5f8269552 (diff) | |
| download | edk2-platforms-b6b3dc4410d0abbda01c76674b18f9c19e8edd9d.tar.xz | |
1, Move introduction from header file to INF file header; 2, Refine dynamic PCD introduction according to review comments
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7997 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdeModulePkg/Universal/PCD/Pei')
| -rw-r--r-- | MdeModulePkg/Universal/PCD/Pei/Pcd.inf | 262 | ||||
| -rw-r--r-- | MdeModulePkg/Universal/PCD/Pei/Service.h | 260 |
2 files changed, 262 insertions, 260 deletions
diff --git a/MdeModulePkg/Universal/PCD/Pei/Pcd.inf b/MdeModulePkg/Universal/PCD/Pei/Pcd.inf index e667a6c0c3..baaa30164d 100644 --- a/MdeModulePkg/Universal/PCD/Pei/Pcd.inf +++ b/MdeModulePkg/Universal/PCD/Pei/Pcd.inf @@ -1,6 +1,268 @@ #/** @file
# PCD PEIM produces PCD database to manage all dynamic PCD in PEI phase and install Pcd Ppi service.
#
+# ////////////////////////////////////////////////////////////////////////////////
+# // //
+# // 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 alsp 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 some C structure and variable 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 auto-generated C structure
+# 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 C structure.
+# PCD Database C structure is generated 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.
+# - 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 - 2008, Intel Corporation
#
# All rights reserved. This program and the accompanying materials
diff --git a/MdeModulePkg/Universal/PCD/Pei/Service.h b/MdeModulePkg/Universal/PCD/Pei/Service.h index 3a25f57e24..ce786a9072 100644 --- a/MdeModulePkg/Universal/PCD/Pei/Service.h +++ b/MdeModulePkg/Universal/PCD/Pei/Service.h @@ -1012,263 +1012,3 @@ extern PEI_PCD_DATABASE_INIT gPEIPcdDbInit; #endif
-////////////////////////////////////////////////////////////////////////////////
-// //
-// Introduction of PCD database //
-// //
-////////////////////////////////////////////////////////////////////////////////
-/**
- 1, Introduction
- PEI PCD database hold all dynamic type PCD information used in PEI phase.
- 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 designed for accessing 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:
- a) The PCD value is produced by someone driver and consumed by other driver
- in execution time.
- b) The PCD value is set/get by user from FrontPage.
- c) The PCD value is produced by platform OEM specified area.
-
- 2.2 According to distribution mehod, dynamic PCD could be classfied as:
- a) Dynamic:
- This type PCD is used for module in source distribution which will be
- built in platform.
- b) DynamicEx:
- This type PCD is used for module in binary distribution which will be
- will not built.
-
- 2.3 According to storage method, dynamic PCD could be classfied as:
- a) Default Storage:
- - The value is stored in PCD database maintained by PCD database in boot
- time memory which is built as a guid hob in PEI phase.
- - 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]/[PcdsDynamicExDefault] is used as section name
- for this type PCD in platform DSC file.
-
- b) Variable Storage:
- - The value is stored in variable area.
- - As default storage type, this type PCD could used for communication.
- But beside it, this type PCD could be used store the value associating
- with HII setting via variable technology.
- - In PEI phase, the PCD value could only be got but can not be set due
- to variable area is readonly for PEI phase.
- - [PcdsDynamicHii]/[PcdsDynamicExHii] is used as section name for this
- type PCD in platform DSC file.
-
- c) OEM specificed storage area:
- - The value is stored in OEM specified area, the base address is specified
- by a FixedAtBuild PCD PcdVpdBaseAddress.
- - The area is read only for PEI and DXE phase.
- - [PcdsDynamicVpd]/[PcdsDynamicExVpd] is used as section name for this
- type PCD in platform DSC file.
-
- Note: The default value of dynamic PCD are storaged in memory maintained
- by PEI/DXE PCD drvier.
-
- 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 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 some C structure and variable 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 auto-generated C structure
- 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 C structure.
- PCD Database C structure is generated 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.
- - 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
-
-**/
|