1## @file 2# PCD PEIM produces PCD database to manage all dynamic PCD in PEI phase and install Pcd Ppi service. 3# 4# This version PCD PEIM depends on the external PCD database binary file, not built in PCD data base. 5# There are two PCD PPIs as follows: 6# 1) PCD_PPI 7# It is EDKII implementation which support Dynamic/DynamicEx Pcds. 8# 2) EFI_PEI_PCD_PPI 9# It is defined by PI specification 1.2, Vol 3 which only support dynamicEx 10# type Pcd. 11# For dynamicEx type PCD, it is compatible between PCD_PPI and EFI_PEI_PCD_PPI. 12# PCD PEIM driver will produce above two PPIs at same time. 13# 14# PCD database is generated as the separate binary image at build time. The binary image 15# will be intergrated into Firmware volume together with PCD driver. 16# 17# //////////////////////////////////////////////////////////////////////////////// 18# // // 19# // Introduction of PCD database // 20# // // 21# //////////////////////////////////////////////////////////////////////////////// 22# 23# 1, Introduction 24# PCD database hold all dynamic type PCD information. The structure of PEI PCD 25# database is generated by build tools according to dynamic PCD usage for 26# specified platform. 27# 28# 2, Dynamic Type PCD 29# Dynamic type PCD is used for the configuration/setting which value is determined 30# dynamic. In contrast, the value of static type PCD (FeatureFlag, FixedPcd, 31# PatchablePcd) is fixed in final generated FD image in build time. 32# 33# 2.1 The "dynamic" determination means one of below cases: 34# a) The PCD setting value is produced by someone driver and consumed by 35# other driver in execution time. 36# b) The PCD setting value is set/get by user from FrontPage. 37# c) The PCD setting value is produced by platform OEM vendor in specified area. 38# 39# 2.2 According to module distribution way, dynamic PCD could be classfied as: 40# a) Dynamic: 41# If module is released in source code and will be built with platform 42# DSC, the dynamic PCD used by this module can be accessed as: 43# PcdGetxx(PcdSampleDynamicPcd); 44# In building platform, build tools will translate PcdSampleDynamicPcd to 45# pair of {Token Space Guid: Token Number} for this PCD. 46# b) DynamicEx: 47# If module is release as binary and will not pariticpate platform building, 48# the dynamic PCD used by this module need be accessed as: 49# PcdGetxxEx(gEfiMyTokenspaceGuid, PcdSampleDynamicPcd) 50# Developer need explicity gives {Token Space Guid:Token Number} as parameter 51# in writting source code. 52# 53# 2.3 According to PCD value's storage method, dynamic PCD could be classfied as: 54# a) Default Storage: 55# - The PCD value is stored in PCD database maintained by PCD driver in boot 56# time memory. 57# - This type is used for communication between PEIM/DXE driver, DXE/DXE 58# driver. But all set/get value will be losted after boot-time memory 59# is turn off. 60# - [PcdsDynamicDefault] is used as section name for this type PCD in 61# platform DSC file. [PcdsDynamicExDefault] is used for dynamicEx type PCD. 62# 63# b) Variable Storage: 64# - The PCD value is stored in variable area. 65# - As default storage type, this type PCD could be used for PEI/DXE driver 66# communication. But beside it, this type PCD could also be used to store 67# the value associate with a HII setting via variable interface. 68# - In PEI phase, the PCD value could only be got but can not be set due 69# to variable area is readonly. 70# - [PcdsDynamicHii] is used as section name for this type PCD in platform 71# DSC file. [PcdsDynamicExHii] is for dynamicEx type PCD. 72# 73# c) OEM specificed storage area: 74# - The PCD value is stored in OEM specified area which base address is 75# specified by a FixedAtBuild PCD setting - PcdVpdBaseAddress. 76# - The area is read only for PEI and DXE phase. 77# - [PcdsDynamicVpd] is used as section name for this type PCD in platform 78# DSC file. [PcdsDynamicExVpd] is for dynamicex type PCD. 79# 80# 2.4 When and how to use dynamic PCD 81# Module developer do not care the used PCD is dynamic or static when writting 82# source code/INF. Dynamic PCD and dynamic type is pointed by platform integrator 83# in platform DSC file. Please ref section 2.3 to get matching between dynamic 84# PCD type and section name in DSC file. 85# 86# 3, PCD database: 87# Although dynamic PCD could be in different storage type as above description, 88# but the basic information and default value for all dynamic PCD is hold 89# by PCD database maintained by PEI/DXE driver. 90# 91# As the whole EFI BIOS boot path is divided into PEI/DXE phase, the PCD database 92# also is divided into Pei/Dxe database maintaied by PcdPeim/PcdDxe driver separatly. 93# To make PcdPeim's driver image smaller, PEI PCD database only hold all dynamic 94# PCD information used in PEI phase or use in both PEI/DXE phase. And DXE PCD 95# database contains all PCDs used in PEI/DXE phase in memory. 96# 97# Build tool will generate PCD database into the separate binary file for 98# PEI/DXE PCD driver according to dynamic PCD section in platform DSC file. 99# 100# 3.1 PcdPeim and PcdDxe 101# PEI PCD database is maintained by PcdPeim driver run from flash. PcdPeim driver 102# build guid hob in temporary memory and copy the binary data base from flash 103# to temporary memory for PEI PCD database. 104# DXE PCD database is maintained by PcdDxe driver.At entry point of PcdDxe driver, 105# a new PCD database is allocated in boot-time memory which including all 106# PEI PCD and DXE PCD entry. 107# 108# Pcd driver should run as early as possible before any other driver access 109# dynamic PCD's value. PEI/DXE "Apriori File" mechanism make it possible by 110# making PcdPeim/PcdDxe as first dispatching driver in PEI/DXE phase. 111# 112# 3.2 Token space Guid/Token number, Platform token, Local token number 113# Dynamic PCD 114# +-----------+ +---------+ 115# |TokenSpace | |Platform | 116# | Guid | build tool | Token | 117# | + +-------------->| Number | 118# | Token | +---------+`._ 119# | Number | `. 120# +-----------+ `. +------+ 121# `-|Local | 122# |Token | 123# DynamicEx PCD ,-|Number| 124# +-----------+ ,-' +------+ 125# |TokenSpace | ,-' 126# | Guid | _,-' 127# | + +.' 128# | Token | 129# | Number | 130# +-----------+ 131# 132# 133# 3.2.1 Pair of Token space guid + Token number 134# Any type PCD is identified by pair of "TokenSpaceGuid + TokeNumber". But it 135# is not easy maintained by PCD driver, and hashed token number will make 136# searching slowly. 137# 138# 3.2.2 Platform Token Number 139# "Platform token number" concept is introduced for mapping to a pair of 140# "TokenSpaceGuid + TokenNumber". The platform token number is generated by 141# build tool in autogen.h and all of them are continual in a platform scope 142# started from 1.(0 meaning invalid internal token number) 143# With auto-generated "platform token number", PcdGet(PcdSampleDynamicPcd) 144# in source code is translated to LibPcdGet(_PCD_TOKEN_PcdSampleDynamicPcd) 145# in autogen.h. 146# Notes: The mapping between pair of "tokenspace guid + token number" and 147# "internal token number" need build tool establish, so "platform token number" 148# mechanism is not suitable for binary module which use DynamicEx type PCD. 149# To access a dynamicEx type PCD, pair of "token space guid/token number" all need 150# to be specificed for PcdSet/PcdGet accessing macro. 151# 152# Platform Token Number is started from 1, and inceased continuous. From whole 153# platform scope, there are two zones: PEI Zone and DXE Zone 154# | Platform Token Number 155# ----------|---------------------------------------------------------------- 156# PEI Zone: | 1 ~ PEI_LOCAL_TOKEN_NUMBER 157# DXE Zone: | (PEI_LOCAL_TOKEN_NUMBER + 1) ~ (PEI_LOCAL_TOKEN_NUMBER + DXE_LOCAL_TOKEN_NUMBER) 158# 159# 3.2.3 Local Token Number 160# To fast searching a PCD entry in PCD database, PCD driver translate 161# platform token number to local token number via a mapping table. 162# For binary DynamicEx type PCD, there is a another mapping table to translate 163# "token space guid + token number" to local token number directly. 164# Local token number is identifier for all internal interface in PCD PEI/DXE 165# driver. 166# 167# A local token number is a 32-bit value in following meaning: 168# 32 ------------- 28 ---------- 24 -------- 0 169# | PCD type mask | Datum Type | Offset | 170# +-----------------------------------------+ 171# where: 172# PCd type mask: indicate Pcd type from following macro: 173# PCD_TYPE_DATA 174# PCD_TYPE_HII 175# PCD_TYPE_VPD 176# PCD_TYPE_SKU_ENABLED 177# PCD_TYPE_STRING 178# Datum Type : indicate PCD vaue type from following macro: 179# PCD_DATUM_TYPE_POINTER 180# PCD_DATUM_TYPE_UINT8 181# PCD_DATUM_TYPE_UINT16 182# PCD_DATUM_TYPE_UINT32 183# PCD_DATUM_TYPE_UINT64 184# Offset : indicate the related offset of PCD value in PCD database array. 185# Based on local token number, PCD driver could fast determine PCD type, value 186# type and get PCD entry from PCD database. 187# 188# 3.3 PCD Database binary file 189# PCD Database binary file will be created at build time as the standalone binary image. 190# To understand the binary image layout, PCD Database C structure is still generated 191# as comments by build tools in PCD driver's autogen.h/ 192# autogen.c file. In generated C structure, following information is stored: 193# - ExMapTable: This table is used translate a binary dynamicex type PCD's 194# "tokenguid + token" to local token number. 195# - LocalTokenNumberTable: 196# This table stores all local token number in array, use "Internal 197# token number" as array index to get PCD entry's offset fastly. 198# - SizeTable: This table stores the size information for all PCD entry. 199# - GuidTable: This table stores guid value for DynamicEx's token space, 200# HII type PCD's variable GUID. 201# - SkuIdTable: TBD 202# - SystemSkuId: TBD 203# - PCD value structure: 204# Every PCD has a value record in PCD database. For different 205# datum type PCD has different record structure which will be 206# introduced in 3.3.1 207# 208# In a PCD database structure, there are two major area: Init and UnInit. 209# Init area is use stored above PCD internal structure such as ExMapTable, 210# LocalTokenNumberTable etc and the (default) value of PCD which has default 211# value specified in platform DSC file. 212# Unint area is used stored the value of PCD which has no default value in 213# platform DSC file, the value of NULL, 0 specified in platform DSC file can 214# be seemed as "no default value". 215# 216# 3.3.1 Simple Sample PCD Database C Structure 217# A general sample of PCD database structue is as follows: 218# typedef struct _PCD_DATABASE { 219# typedef struct _PCD_DATABASE_INIT { 220# //===== Following is PCD database internal maintain structures 221# DYNAMICEX_MAPPING ExMapTable[PEI_EXMAPPING_TABLE_SIZE]; 222# UINT32 LocalTokenNumberTable[PEI_LOCAL_TOKEN_NUMBER_TABLE_SIZE]; 223# GUID GuidTable[PEI_GUID_TABLE_SIZE]; 224# SIZE_INFO SizeTable[PEI_SIZE_TABLE_SIZE]; 225# UINT8 SkuIdTable[PEI_SKUID_TABLE_SIZE]; 226# SKU_ID SystemSkuId; 227# 228# //===== Following is value structure for PCD with default value 229# .... 230# .... 231# .... 232# } Init; 233# typedef struct _PCD_DATABSE_UNINIT { 234# //==== Following is value structure for PCD without default value 235# .... 236# .... 237# } UnInit; 238# } 239# 240# 3.3.2 PCD value structure in PCD database C structure 241# The value's structure is generated by build tool in PCD database C structure. 242# The PCDs in different datum type has different value structure. 243# 244# 3.3.2.1 UINT8/UINT16/UINT32/UINT64 datum type PCD 245# The C structure for these datum type PCD is just a UINT8/UINT16/UINT32/UINT64 246# data member in PCD database, For example: 247# UINT16 PcdHardwareErrorRecordLevel_d3705011_bc19_4af7_be16_f68030378c15_VariableDefault_0; 248# Above structure is generated by build tool, the member name is "PcdCName_Guidvalue" 249# Member type is UINT16 according to PcdHardwareErrorRecordLevel declaration 250# in DEC file. 251# 252# 3.3.2.2 VOID* datum type PCD 253# The value of VOID* datum type PCD is a UINT8/UINT16 array in PCD database. 254# 255# 3.3.2.2.1 VOID* - string type 256# If the default value for VOID* datum type PCD like L"xxx", the PCD is 257# used for unicode string, and C structure of this datum type PCD is 258# UINT16 string array in PCD database, for example: 259# UINT16 StringTable[29]; 260# The number of 29 in above sample is max size of a unicode string. 261# 262# If the default value for VOID* datum type PCD like "xxx", the PCD is 263# used for ascii string, and C structure of this datum type PCD is 264# UINT8 string array in PCD database, for example: 265# UINT8 StringTable[20]; 266# The number of 20 in above sample is max size of a ascii string. 267# 268# 3.3.2.2.2 VOID* - byte array 269# If the default value of VOID* datum type PCD like {'0x29', '0x01', '0xf2'} 270# the PCD is used for byte array. The generated structrue is same as 271# above ascii string table, 272# UINT8 StringTable[13]; 273# The number of 13 in above sample is max size of byte array. 274# 275# 3.3.3 Some utility structures in PCD Database 276# 3.3.3.1 GuidTable 277# GuidTable array is used to store all related GUID value in PCD database: 278# - Variable GUID for HII type PCD 279# - Token space GUID for dynamicex type PCD 280# 281# Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR> 282# 283# This program and the accompanying materials 284# are licensed and made available under the terms and conditions of the BSD License 285# which accompanies this distribution. The full text of the license may be found at 286# http://opensource.org/licenses/bsd-license.php 287# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 288# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 289# 290# 291## 292 293[Defines] 294 INF_VERSION = 0x00010005 295 BASE_NAME = PcdPeim 296 MODULE_UNI_FILE = PcdPeim.uni 297 FILE_GUID = 9B3ADA4F-AE56-4c24-8DEA-F03B7558AE50 298 MODULE_TYPE = PEIM 299 VERSION_STRING = 4.0 300 PCD_IS_DRIVER = PEI_PCD_DRIVER 301 ENTRY_POINT = PcdPeimInit 302 303# 304# The following information is for reference only and not required by the build tools. 305# 306# VALID_ARCHITECTURES = IA32 X64 IPF EBC (EBC is for build only) 307# 308 309[Sources] 310 Service.c 311 Service.h 312 Pcd.c 313 314[Packages] 315 MdePkg/MdePkg.dec 316 MdeModulePkg/MdeModulePkg.dec 317 318[LibraryClasses] 319 BaseMemoryLib 320 PcdLib 321 PeiServicesLib 322 HobLib 323 BaseLib 324 PeimEntryPoint 325 DebugLib 326 MemoryAllocationLib 327 328[Guids] 329 ## PRODUCES ## HOB 330 ## SOMETIMES_CONSUMES ## HOB 331 gPcdDataBaseHobGuid 332 gPcdDataBaseSignatureGuid ## CONSUMES ## GUID # PCD database signature GUID. 333 334[Ppis] 335 gEfiPeiReadOnlyVariable2PpiGuid ## SOMETIMES_CONSUMES 336 gPcdPpiGuid ## PRODUCES 337 gEfiPeiPcdPpiGuid ## PRODUCES 338 gGetPcdInfoPpiGuid ## SOMETIMES_PRODUCES 339 gEfiGetPcdInfoPpiGuid ## SOMETIMES_PRODUCES 340 341[FeaturePcd] 342 gEfiMdeModulePkgTokenSpaceGuid.PcdPeiFullPcdDatabaseEnable ## CONSUMES 343 344[Pcd] 345 gEfiMdeModulePkgTokenSpaceGuid.PcdVpdBaseAddress ## SOMETIMES_CONSUMES 346 gEfiMdeModulePkgTokenSpaceGuid.PcdMaxPeiPcdCallBackNumberPerPcdEntry || gEfiMdeModulePkgTokenSpaceGuid.PcdPeiFullPcdDatabaseEnable ## SOMETIMES_CONSUMES 347 348[Depex] 349 TRUE 350 351[UserExtensions.TianoCore."ExtraFiles"] 352 PcdPeimExtra.uni 353