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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
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klu2 2009-04-01 06:43:16 +00:00
parent 62c236c065
commit b6b3dc4410
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262
MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
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@ -3,6 +3,268 @@
# PEI phase, DXE phase and produce the implementation of PCD protocol.
# PCD database structure is generated at autogen.h/autogen.c in build time.
#
# ////////////////////////////////////////////////////////////////////////////////
# // //
# // 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 - 2009, Intel Corporation
#
# All rights reserved. This program and the accompanying materials

262
MdeModulePkg/Universal/PCD/Dxe/Service.h
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@ -1066,265 +1066,3 @@ extern EFI_LOCK mPcdDatabaseLock;
#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
3.4 PEI PCD Database
**/

262
MdeModulePkg/Universal/PCD/Pei/Pcd.inf
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@ -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

260
MdeModulePkg/Universal/PCD/Pei/Service.h
View File

@ -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
**/