Update the comments.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5261 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Compatibility/PciCfg2ToPciCfgThunk/PciCfg2ToPciCfgThunk.c

@@ -1,9 +1,13 @@
 /** @file
  Module produces PciCfgPpi2 on top of PciCfgPpi. It also updates the 
  PciCfg2Ppi pointer in the EFI_PEI_SERVICES upon a installation of
-EcpPeiPciCfgPpi. EcpPeiPciCfgPpi is installed in a framework module which
+ EcpPeiPciCfgPpi. 
-produce PciCfgPpi originally. This framework module is updated based on the 
+
-following rule:
+ EcpPeiPciCfgPpi is installed by a framework module which
+ produce PciCfgPpi originally. Such framework module is updated based on the 
+ following rule to install EcpPeiPciCfgPpi instead of updating the PciCfg pointer
+ in the Framework PeiServicesTable: 
+ 
  Search pattern:
  	   PeiServices->PciCfg = <*>;
  Replace pattern:
@@ -16,6 +20,36 @@ Replace pattern:
            (**PeiServices).InstallPpi (PeiServices, gEcpPeiPciCfgPpiList);
          }
  
+ In addition, the PeiServicesTable definition in PeiApi.h is updated to
+ 
+ struct _EFI_PEI_SERVICES {
+   EFI_TABLE_HEADER              Hdr;
+   ...
+ 
+   //
+   // Pointer to PPI interface
+   //
+ if (PI_SPECIFICATION_VERSION < 0x00010000)
+ 
+   PEI_CPU_IO_PPI                 *CpuIo;
+   ECP_PEI_PCI_CFG_PPI        *PciCfg;  //Changed.
+ else
+ ...
+ endif
+ 
+ };
+ 
+ This change enable the detection of code segment which invokes PeiServices->PciCfg->Modify.
+ Such code causes a build break as ECP_PEI_PCI_CFG_PPI does not has "Modify" field. 
+ This should be updated to a call to PeiLibPciCfgModify as shown below:
+ 
+ Search pattern:
+ 		*->Modify(<*>); 
+ Replace pattern:
+ 		PeiLibPciCfgModify(<*>);
+
+
+
 PIWG's PI specification replaces Inte's EFI Specification 1.10.
 EFI_PEI_PCI_CFG_PPI defined in Inte's EFI Specification 1.10 is replaced by
 EFI_PEI_PCI_CFG2_PPI in PI 1.0.

EdkCompatibilityPkg/Compatibility/PciCfg2ToPciCfgThunk/PciCfg2ToPciCfgThunk.inf

@@ -1,9 +1,13 @@
 #/** @file
 # Module produces PciCfgPpi2 on top of PciCfgPpi. It also updates the 
 # PciCfg2Ppi pointer in the EFI_PEI_SERVICES upon a installation of
-# EcpPeiPciCfgPpi. EcpPeiPciCfgPpi is installed in a framework module which
+# EcpPeiPciCfgPpi. 
-# produce PciCfgPpi originally. This framework module is updated based on the 
+#
-# following rule:
+# EcpPeiPciCfgPpi is installed by a framework module which
+# produce PciCfgPpi originally. Such framework module is updated based on the 
+# following rule to install EcpPeiPciCfgPpi instead of updating the PciCfg pointer
+# in the Framework PeiServicesTable: 
+# 
 # Search pattern:
 # 	   PeiServices->PciCfg = <*>;
 # Replace pattern:
@@ -15,7 +19,35 @@
 #           };
 #           (**PeiServices).InstallPpi (PeiServices, gEcpPeiPciCfgPpiList);
 #         }
-
+# 
+# In addition, the PeiServicesTable definition in PeiApi.h is updated to
+# 
+# struct _EFI_PEI_SERVICES {
+#   EFI_TABLE_HEADER              Hdr;
+#   ...
+# 
+#   //
+#   // Pointer to PPI interface
+#   //
+# #if (PI_SPECIFICATION_VERSION < 0x00010000)
+# 
+#   PEI_CPU_IO_PPI                 *CpuIo;
+#   ECP_PEI_PCI_CFG_PPI        *PciCfg;  //Changed.
+# #else
+# ...
+# #endif
+# 
+# };
+# 
+# This change enable the detection of code segment which invokes PeiServices->PciCfg->Modify.
+# Such code causes a build break as ECP_PEI_PCI_CFG_PPI does not has "Modify" field. 
+# This should be updated to a call to PeiLibPciCfgModify as shown below:
+# 
+# Search pattern:
+# 		*->Modify(<*>); 
+# Replace pattern:
+# 		PeiLibPciCfgModify(<*>);
+#
 # PIWG's PI specification replaces Inte's EFI Specification 1.10.
 # EFI_PEI_PCI_CFG_PPI defined in Inte's EFI Specification 1.10 is replaced by
 # EFI_PEI_PCI_CFG2_PPI in PI 1.0.