Pcd.inf revision 639710791a0c3735890194f88dfbf33070f5d4e1
1## @file 2# PCD PEIM produces PCD database to manage all dynamic PCD in PEI phase and install Pcd Ppi service. 3# 4# There are two PCD PPIs as follows: 5# 1) PCD_PPI 6# It is EDKII implementation which support Dynamic/DynamicEx Pcds. 7# 2) EFI_PEI_PCD_PPI 8# It is defined by PI specification 1.2, Vol 3 which only support dynamicEx 9# type Pcd. 10# For dynamicEx type PCD, it is compatible between PCD_PPI and EFI_PEI_PCD_PPI. 11# 12# //////////////////////////////////////////////////////////////////////////////// 13# // // 14# // Introduction of PCD database // 15# // // 16# //////////////////////////////////////////////////////////////////////////////// 17# 18# 1, Introduction 19# PCD database hold all dynamic type PCD information. The structure of PEI PCD 20# database is generated by build tools according to dynamic PCD usage for 21# specified platform. 22# 23# 2, Dynamic Type PCD 24# Dynamic type PCD is used for the configuration/setting which value is determined 25# dynamic. In contrast, the value of static type PCD (FeatureFlag, FixedPcd, 26# PatchablePcd) is fixed in final generated FD image in build time. 27# 28# 2.1 The "dynamic" determination means one of below cases: 29# a) The PCD setting value is produced by someone driver and consumed by 30# other driver in execution time. 31# b) The PCD setting value is set/get by user from FrontPage. 32# c) The PCD setting value is produced by platform OEM vendor in specified area. 33# 34# 2.2 According to module distribution way, dynamic PCD could be classfied as: 35# a) Dynamic: 36# If module is released in source code and will be built with platform 37# DSC, the dynamic PCD used by this module can be accessed as: 38# PcdGetxx(PcdSampleDynamicPcd); 39# In building platform, build tools will translate PcdSampleDynamicPcd to 40# pair of {Token Space Guid: Token Number} for this PCD. 41# b) DynamicEx: 42# If module is release as binary and will not pariticpate platform building, 43# the dynamic PCD used by this module need be accessed as: 44# PcdGetxxEx(gEfiMyTokenspaceGuid, PcdSampleDynamicPcd) 45# Developer need explicity gives {Token Space Guid:Token Number} as parameter 46# in writting source code. 47# 48# 2.3 According to PCD value's storage method, dynamic PCD could be classfied as: 49# a) Default Storage: 50# - The PCD value is stored in PCD database maintained by PCD driver in boot 51# time memory. 52# - This type is used for communication between PEIM/DXE driver, DXE/DXE 53# driver. But all set/get value will be losted after boot-time memory 54# is turn off. 55# - [PcdsDynamicDefault] is used as section name for this type PCD in 56# platform DSC file. [PcdsDynamicExDefault] is used for dynamicEx type PCD. 57# 58# b) Variable Storage: 59# - The PCD value is stored in variable area. 60# - As default storage type, this type PCD could be used for PEI/DXE driver 61# communication. But beside it, this type PCD could alsp be used to store 62# the value associate with a HII setting via variable interface. 63# - In PEI phase, the PCD value could only be got but can not be set due 64# to variable area is readonly. 65# - [PcdsDynamicHii] is used as section name for this type PCD in platform 66# DSC file. [PcdsDynamicExHii] is for dynamicEx type PCD. 67# 68# c) OEM specificed storage area: 69# - The PCD value is stored in OEM specified area which base address is 70# specified by a FixedAtBuild PCD setting - PcdVpdBaseAddress. 71# - The area is read only for PEI and DXE phase. 72# - [PcdsDynamicVpd] is used as section name for this type PCD in platform 73# DSC file. [PcdsDynamicExVpd] is for dynamicex type PCD. 74# 75# 2.4 When and how to use dynamic PCD 76# Module developer do not care the used PCD is dynamic or static when writting 77# source code/INF. Dynamic PCD and dynamic type is pointed by platform integrator 78# in platform DSC file. Please ref section 2.3 to get matching between dynamic 79# PCD type and section name in DSC file. 80# 81# 3, PCD database: 82# Although dynamic PCD could be in different storage type as above description, 83# but the basic information and default value for all dynamic PCD is hold 84# by PCD database maintained by PEI/DXE driver. 85# 86# As the whole EFI BIOS boot path is divided into PEI/DXE phase, the PCD database 87# also is divided into Pei/Dxe database maintaied by PcdPeim/PcdDxe driver separatly. 88# To make PcdPeim's driver image smaller, PEI PCD database only hold all dynamic 89# PCD information used in PEI phase or use in both PEI/DXE phase. And DXE PCD 90# database contains all PCDs used in PEI/DXE phase in memory. 91# 92# Build tool will generate PCD database into some C structure and variable for 93# PEI/DXE PCD driver according to dynamic PCD section in platform DSC file. 94# 95# 3.1 PcdPeim and PcdDxe 96# PEI PCD database is maintained by PcdPeim driver run from flash. PcdPeim driver 97# build guid hob in temporary memory and copy auto-generated C structure 98# to temporary memory for PEI PCD database. 99# DXE PCD database is maintained by PcdDxe driver.At entry point of PcdDxe driver, 100# a new PCD database is allocated in boot-time memory which including all 101# PEI PCD and DXE PCD entry. 102# 103# Pcd driver should run as early as possible before any other driver access 104# dynamic PCD's value. PEI/DXE "Apriori File" mechanism make it possible by 105# making PcdPeim/PcdDxe as first dispatching driver in PEI/DXE phase. 106# 107# 3.2 Token space Guid/Token number, Platform token, Local token number 108# Dynamic PCD 109# +-----------+ +---------+ 110# |TokenSpace | |Platform | 111# | Guid | build tool | Token | 112# | + +-------------->| Number | 113# | Token | +---------+`._ 114# | Number | `. 115# +-----------+ `. +------+ 116# `-|Local | 117# |Token | 118# DynamicEx PCD ,-|Number| 119# +-----------+ ,-' +------+ 120# |TokenSpace | ,-' 121# | Guid | _,-' 122# | + +.' 123# | Token | 124# | Number | 125# +-----------+ 126# 127# 128# 3.2.1 Pair of Token space guid + Token number 129# Any type PCD is identified by pair of "TokenSpaceGuid + TokeNumber". But it 130# is not easy maintained by PCD driver, and hashed token number will make 131# searching slowly. 132# 133# 3.2.2 Platform Token Number 134# "Platform token number" concept is introduced for mapping to a pair of 135# "TokenSpaceGuid + TokenNumber". The platform token number is generated by 136# build tool in autogen.h and all of them are continual in a platform scope 137# started from 1.(0 meaning invalid internal token number) 138# With auto-generated "platform token number", PcdGet(PcdSampleDynamicPcd) 139# in source code is translated to LibPcdGet(_PCD_TOKEN_PcdSampleDynamicPcd) 140# in autogen.h. 141# Notes: The mapping between pair of "tokenspace guid + token number" and 142# "internal token number" need build tool establish, so "platform token number" 143# mechanism is not suitable for binary module which use DynamicEx type PCD. 144# To access a dynamicEx type PCD, pair of "token space guid/token number" all need 145# to be specificed for PcdSet/PcdGet accessing macro. 146# 147# Platform Token Number is started from 1, and inceased continuous. From whole 148# platform scope, there are two zones: PEI Zone and DXE Zone 149# | Platform Token Number 150# ----------|---------------------------------------------------------------- 151# PEI Zone: | 1 ~ PEI_LOCAL_TOKEN_NUMBER 152# DXE Zone: | (PEI_LOCAL_TOKEN_NUMBER + 1) ~ (PEI_LOCAL_TOKEN_NUMBER + DXE_LOCAL_TOKEN_NUMBER) 153# 154# 3.2.3 Local Token Number 155# To fast searching a PCD entry in PCD database, PCD driver translate 156# platform token number to local token number via a mapping table. 157# For binary DynamicEx type PCD, there is a another mapping table to translate 158# "token space guid + token number" to local token number directly. 159# Local token number is identifier for all internal interface in PCD PEI/DXE 160# driver. 161# 162# A local token number is a 32-bit value in following meaning: 163# 32 ------------- 28 ---------- 24 -------- 0 164# | PCD type mask | Datum Type | Offset | 165# +-----------------------------------------+ 166# where: 167# PCd type mask: indicate Pcd type from following macro: 168# PCD_TYPE_DATA 169# PCD_TYPE_HII 170# PCD_TYPE_VPD 171# PCD_TYPE_SKU_ENABLED 172# PCD_TYPE_STRING 173# Datum Type : indicate PCD vaue type from following macro: 174# PCD_DATUM_TYPE_POINTER 175# PCD_DATUM_TYPE_UINT8 176# PCD_DATUM_TYPE_UINT16 177# PCD_DATUM_TYPE_UINT32 178# PCD_DATUM_TYPE_UINT64 179# Offset : indicate the related offset of PCD value in PCD database array. 180# Based on local token number, PCD driver could fast determine PCD type, value 181# type and get PCD entry from PCD database. 182# 183# 3.3 PCD Database C structure. 184# PCD Database C structure is generated by build tools in PCD driver's autogen.h/ 185# autogen.c file. In generated C structure, following information is stored: 186# - ExMapTable: This table is used translate a binary dynamicex type PCD's 187# "tokenguid + token" to local token number. 188# - LocalTokenNumberTable: 189# This table stores all local token number in array, use "Internal 190# token number" as array index to get PCD entry's offset fastly. 191# - SizeTable: This table stores the size information for all PCD entry. 192# - GuidTable: This table stores guid value for DynamicEx's token space, 193# HII type PCD's variable. 194# - SkuIdTable: TBD 195# - SystemSkuId: TBD 196# - PCD value structure: 197# Every PCD has a value record in PCD database. For different 198# datum type PCD has different record structure which will be 199# introduced in 3.3.1 200# 201# In a PCD database structure, there are two major area: Init and UnInit. 202# Init area is use stored above PCD internal structure such as ExMapTable, 203# LocalTokenNumberTable etc and the (default) value of PCD which has default 204# value specified in platform DSC file. 205# Unint area is used stored the value of PCD which has no default value in 206# platform DSC file, the value of NULL, 0 specified in platform DSC file can 207# be seemed as "no default value". 208# 209# 3.3.1 Simple Sample PCD Database C Structure 210# A general sample of PCD database structue is as follows: 211# typedef struct _PCD_DATABASE { 212# typedef struct _PCD_DATABASE_INIT { 213# //===== Following is PCD database internal maintain structures 214# DYNAMICEX_MAPPING ExMapTable[PEI_EXMAPPING_TABLE_SIZE]; 215# UINT32 LocalTokenNumberTable[PEI_LOCAL_TOKEN_NUMBER_TABLE_SIZE]; 216# GUID GuidTable[PEI_GUID_TABLE_SIZE]; 217# SIZE_INFO SizeTable[PEI_SIZE_TABLE_SIZE]; 218# UINT8 SkuIdTable[PEI_SKUID_TABLE_SIZE]; 219# SKU_ID SystemSkuId; 220# 221# //===== Following is value structure for PCD with default value 222# .... 223# .... 224# .... 225# } Init; 226# typedef struct _PCD_DATABSE_UNINIT { 227# //==== Following is value structure for PCD without default value 228# .... 229# .... 230# } UnInit; 231# } 232# 233# 3.3.2 PCD value structure in PCD database C structure 234# The value's structure is generated by build tool in PCD database C structure. 235# The PCDs in different datum type has different value structure. 236# 237# 3.3.2.1 UINT8/UINT16/UINT32/UINT64 datum type PCD 238# The C structure for these datum type PCD is just a UINT8/UINT16/UINT32/UINT64 239# data member in PCD database, For example: 240# UINT16 PcdHardwareErrorRecordLevel_d3705011_bc19_4af7_be16_f68030378c15_VariableDefault_0; 241# Above structure is generated by build tool, the member name is "PcdCName_Guidvalue" 242# Member type is UINT16 according to PcdHardwareErrorRecordLevel declaration 243# in DEC file. 244# 245# 3.3.2.2 VOID* datum type PCD 246# The value of VOID* datum type PCD is a UINT8/UINT16 array in PCD database. 247# 248# 3.3.2.2.1 VOID* - string type 249# If the default value for VOID* datum type PCD like L"xxx", the PCD is 250# used for unicode string, and C structure of this datum type PCD is 251# UINT16 string array in PCD database, for example: 252# UINT16 StringTable[29]; 253# The number of 29 in above sample is max size of a unicode string. 254# 255# If the default value for VOID* datum type PCD like "xxx", the PCD is 256# used for ascii string, and C structure of this datum type PCD is 257# UINT8 string array in PCD database, for example: 258# UINT8 StringTable[20]; 259# The number of 20 in above sample is max size of a ascii string. 260# 261# 3.3.2.2.2 VOID* - byte array 262# If the default value of VOID* datum type PCD like {'0x29', '0x01', '0xf2'} 263# the PCD is used for byte array. The generated structrue is same as 264# above ascii string table, 265# UINT8 StringTable[13]; 266# The number of 13 in above sample is max size of byte array. 267# 268# 3.3.3 Some utility structures in PCD Database 269# 3.3.3.1 GuidTable 270# GuidTable array is used to store all related GUID value in PCD database: 271# - Variable GUID for HII type PCD 272# - Token space GUID for dynamicex type PCD 273# 274# Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR> 275# 276# This program and the accompanying materials 277# are licensed and made available under the terms and conditions of the BSD License 278# which accompanies this distribution. The full text of the license may be found at 279# http://opensource.org/licenses/bsd-license.php 280# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 281# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 282# 283# 284## 285 286[Defines] 287 INF_VERSION = 0x00010005 288 BASE_NAME = PcdPeim 289 FILE_GUID = 9B3ADA4F-AE56-4c24-8DEA-F03B7558AE50 290 MODULE_TYPE = PEIM 291 VERSION_STRING = 1.0 292 PCD_IS_DRIVER = PEI_PCD_DRIVER 293 ENTRY_POINT = PcdPeimInit 294 295# 296# The following information is for reference only and not required by the build tools. 297# 298# VALID_ARCHITECTURES = IA32 X64 IPF EBC (EBC is for build only) 299# 300 301[Sources] 302 Service.c 303 Service.h 304 Pcd.c 305 306[Packages] 307 MdePkg/MdePkg.dec 308 MdeModulePkg/MdeModulePkg.dec 309 310[LibraryClasses] 311 BaseMemoryLib 312 PcdLib 313 PeiServicesLib 314 HobLib 315 BaseLib 316 PeimEntryPoint 317 DebugLib 318 319[Guids] 320 gPcdDataBaseHobGuid ## PRODUCES ## Hob 321 gPcdDataBaseHobGuid ## CONSUMES ## Hob 322 323[Ppis] 324 gEfiPeiReadOnlyVariable2PpiGuid ## CONSUMES 325 gPcdPpiGuid ## PRODUCES 326 gEfiPeiPcdPpiGuid ## PRODUCES 327 328[FeaturePcd] 329 gEfiMdeModulePkgTokenSpaceGuid.PcdPeiFullPcdDatabaseEnable 330 331[Pcd] 332 gEfiMdeModulePkgTokenSpaceGuid.PcdVpdBaseAddress 333 gEfiMdeModulePkgTokenSpaceGuid.PcdMaxPeiPcdCallBackNumberPerPcdEntry || gEfiMdeModulePkgTokenSpaceGuid.PcdPeiFullPcdDatabaseEnable 334 335[Depex] 336 TRUE 337 338