MdeModulePkg/PciBus: Do not enable MemWriteAndInvalidate bit for PCIE

Per PCIE spec, Memory Write and Invalidate is hardwired to 0b so
PciBus driver shouldn't write 1b to it.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
index 81171c82d9e21500ceaf25464d78d196904b02b2..6f3d1bebc6c298fbba88bffa660fff1b0f81fdd0 100644 (file)
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
@@ -1,7 +1,7 @@
 /** @file\r
   PCI emumeration support functions implementation for PCI Bus module.\r
 \r
 /** @file\r
   PCI emumeration support functions implementation for PCI Bus module.\r
 \r

-Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>\r

 (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>\r
 This program and the accompanying materials\r
 are licensed and made available under the terms and conditions of the BSD License\r
 (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>\r
 This program and the accompanying materials\r
 are licensed and made available under the terms and conditions of the BSD License\r


@@ -1254,9 +1254,11 @@ DetermineDeviceAttribute (
     PciSetDeviceAttribute (PciIoDevice, OldCommand, OldBridgeControl, EFI_SET_ATTRIBUTES);\r
 \r
     //\r
     PciSetDeviceAttribute (PciIoDevice, OldCommand, OldBridgeControl, EFI_SET_ATTRIBUTES);\r
 \r
     //\r

-    // Enable other supported attributes but not defined in PCI_IO_PROTOCOL\r
-    //\r
-    PCI_ENABLE_COMMAND_REGISTER (PciIoDevice, EFI_PCI_COMMAND_MEMORY_WRITE_AND_INVALIDATE);\r
+    // Enable other PCI supported attributes but not defined in PCI_IO_PROTOCOL\r
+    // For PCI Express devices, Memory Write and Invalidate is hardwired to 0b so only enable it for PCI devices.\r
+    if (!PciIoDevice->IsPciExp) {\r
+      PCI_ENABLE_COMMAND_REGISTER (PciIoDevice, EFI_PCI_COMMAND_MEMORY_WRITE_AND_INVALIDATE);\r
+    }\r

   }\r
 \r
   FastB2BSupport = TRUE;\r
   }\r
 \r
   FastB2BSupport = TRUE;\r