From: Ruiyu Ni <ruiyu.ni@intel.com>
Date: Thu, 30 Jul 2015 06:40:36 +0000 (+0000)
Subject: MdeModulePkg: Enhance PciBusDxe to handle high 32bit of MEM64 BAR returns 0
X-Git-Tag: edk2-stable201903~9167
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=5c13180cfc9827f11174995a5211d6dde2a1ef31

MdeModulePkg: Enhance PciBusDxe to handle high 32bit of MEM64 BAR returns 0

According to the PCI spec, when software writes all-one to BAR for size probing,
the value read back should be 0b1...10...0 after masking the BAR type bits.
But in real world, it's possible that certain device returns 0b0...01...10...0
for MEM64 BAR size probing: some bits in the high 32bit may be 0.
PciBus driver has the code to handle such case. However, it doesn't handle the
case that the high 32bit is totally 0. The patch is to handle the special case.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18114 6f19259b-4bc3-4df7-8a09-765794883524
---

diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
index 9e7ac74eb7..f46025e2f6 100644
--- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
+++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
@@ -1,7 +1,7 @@
 /** @file
   PCI emumeration support functions implementation for PCI Bus module.
 
-Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -1770,14 +1770,19 @@ PciParseBar (
           // some device implement MMIO bar with 0 length, need to treat it as no-bar
           //
           PciIoDevice->PciBar[BarIndex].BarType = PciBarTypeUnknown;
+          return Offset + 4;
         }
-        return Offset + 4;
       }
 
       //
       // Fix the length to support some spefic 64 bit BAR
       //
-      Value |= ((UINT32)(-1) << HighBitSet32 (Value));
+      if (Value == 0) {
+        DEBUG ((EFI_D_INFO, "[PciBus]BAR probing for upper 32bit of MEM64 BAR returns 0, change to 0xFFFFFFFF.\n"));
+        Value = (UINT32) -1;
+      } else {
+        Value |= ((UINT32)(-1) << HighBitSet32 (Value));
+      }
 
       //
       // Calculate the size of 64bit bar