[patch] MdeModulePkg/Ehci: don't clear port status bits during init

[Feng Tian <feng.tian@intel.com>]

Port status bits are clear in original code, so no enumeration
takes place.
Changing this to prevent the status bits from being cleared
allows enumeration to proceed normally.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Mike Turner <Michael.Turner@microsoft.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Mike Turner <Michael.Turner@microsoft.com>
Signed-off-by: Feng Tian <feng.tian@intel.com>
---
 MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c | 10 +++++++++-
 MdeModulePkg/Bus/Pci/EhciPei/EhcPeim.c | 18 +++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c b/MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c
index 88a66ae..3a6ed02 100644
--- a/MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c
+++ b/MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.c
@@ -591,6 +591,7 @@ EhcInitHC (
 {
   EFI_STATUS              Status;
   UINT32                  Index;
+  UINT32                  RegVal;
 
   // This ASSERT crashes the BeagleBoard. There is some issue in the USB stack.
   // This ASSERT needs to be removed so the BeagleBoard will boot. When we fix
@@ -626,7 +627,14 @@ EhcInitHC (
   //
   if (Ehc->HcStructParams & HCSP_PPC) {
     for (Index = 0; Index < (UINT8) (Ehc->HcStructParams & HCSP_NPORTS); Index++) {
-      EhcSetOpRegBit (Ehc, (UINT32) (EHC_PORT_STAT_OFFSET + (4 * Index)), PORTSC_POWER);
+      //
+      // Do not clear port status bits on initialization.  Otherwise devices will
+      // not enumerate properly at startup.
+      //
+      RegVal  = EhcReadOpReg(Ehc, (UINT32)(EHC_PORT_STAT_OFFSET + (4 * Index)));
+      RegVal &= ~PORTSC_CHANGE_MASK;
+      RegVal |= PORTSC_POWER;
+      EhcWriteOpReg (Ehc, (UINT32) (EHC_PORT_STAT_OFFSET + (4 * Index)), RegVal);
     }
   }
 
diff --git a/MdeModulePkg/Bus/Pci/EhciPei/EhcPeim.c b/MdeModulePkg/Bus/Pci/EhciPei/EhcPeim.c
index 09769ea..31647ff 100644
--- a/MdeModulePkg/Bus/Pci/EhciPei/EhcPeim.c
+++ b/MdeModulePkg/Bus/Pci/EhciPei/EhcPeim.c
@@ -2,7 +2,7 @@
 PEIM to produce gPeiUsb2HostControllerPpiGuid based on gPeiUsbControllerPpiGuid
 which is used to enable recovery function from USB Drivers.
 
-Copyright (c) 2010 - 2013, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2010 - 2016, Intel Corporation. All rights reserved.<BR>
   
 This program and the accompanying materials
 are licensed and made available under the terms and conditions
@@ -411,12 +411,20 @@ EhcPowerOnAllPorts (
   IN PEI_USB2_HC_DEV          *Ehc
   )
 {
-  UINT8 PortNumber;
-  UINT8 Index;
-
+  UINT8     PortNumber;
+  UINT8     Index;
+  UINT32    RegVal;
+  
   PortNumber = (UINT8)(Ehc->HcStructParams & HCSP_NPORTS);
   for (Index = 0; Index < PortNumber; Index++) {
-    EhcSetOpRegBit (Ehc, EHC_PORT_STAT_OFFSET + 4 * Index, PORTSC_POWER);
+    //
+    // Do not clear port status bits on initialization.  Otherwise devices will
+    // not enumerate properly at startup.
+    //
+    RegVal  = EhcReadOpReg(Ehc, EHC_PORT_STAT_OFFSET + 4 * Index);
+    RegVal &= ~PORTSC_CHANGE_MASK;
+    RegVal |= PORTSC_POWER;
+    EhcWriteOpReg (Ehc, EHC_PORT_STAT_OFFSET + 4 * Index, RegVal);
   }
 }
 
-- 
2.7.1.windows.2