[PATCH 2/2] MdeModulePkg/PciBusDxe: Install PciEnumerationComplete after PciIo

[Ruiyu Ni <ruiyu.ni@intel.com>]

Per PI spec, the PciEnumerationComplete protocol installation
should be after PciIo installation.
Today's implementation installs the PciEnumerationComplete
after hardware enumeration is completed, but before PciIo
installation.
The change corrects the spec/implementation gap.
The change also benefits certain implementation that depends on
the PciIo handle in PciEnumerationComplete callback.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
---
 MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c        | 15 +++++++++++++--
 MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c | 10 ----------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
index 3bb5099bd3..c48e3bba96 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c
@@ -360,8 +360,19 @@ PciBusDriverBindingStart (
   //
   StartPciDevices (Controller);
 
-  gFullEnumeration = FALSE;
-  return EFI_SUCCESS;
+  if (gFullEnumeration) {
+    gFullEnumeration = FALSE;
+
+    Status = gBS->InstallProtocolInterface (
+                    &PciRootBridgeIo->ParentHandle,
+                    &gEfiPciEnumerationCompleteProtocolGuid,
+                    EFI_NATIVE_INTERFACE,
+                    NULL
+                    );
+    ASSERT_EFI_ERROR (Status);
+  }
+
+  return Status;
 }
 
 /**
diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
index f6aa327493..d5d3c07393 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumerator.c
@@ -104,16 +104,6 @@ PciEnumerator (
     return Status;
   }
 
-  Status = gBS->InstallProtocolInterface (
-                  &HostBridgeHandle,
-                  &gEfiPciEnumerationCompleteProtocolGuid,
-                  EFI_NATIVE_INTERFACE,
-                  NULL
-                  );
-  if (EFI_ERROR (Status)) {
-    return Status;
-  }
-
   return EFI_SUCCESS;
 }
 
-- 
2.15.1.windows.2