add error handling on usb related modules.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9566 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c

@@ -1884,6 +1884,12 @@ EhcDriverBindingStop (
     FreeUnicodeStringTable (Ehc->ControllerNameTable);
   }
 
+  //
+  // Disable routing of all ports to EHCI controller, so all ports are 
+  // routed back to the UHCI controller.
+  //
+  EhcClearOpRegBit (Ehc, EHC_CONFIG_FLAG_OFFSET, CONFIGFLAG_ROUTE_EHC);
+
   //
   // Restore original PCI attributes
   //

MdeModulePkg/Bus/Pci/EhciDxe/EhciReg.h

@@ -160,6 +160,35 @@ EhcWriteOpReg (
   IN UINT32               Data
   );
 
+/**
+  Set one bit of the operational register while keeping other bits.
+
+  @param  Ehc          The EHCI device.
+  @param  Offset       The offset of the operational register.
+  @param  Bit          The bit mask of the register to set.
+
+**/
+VOID
+EhcSetOpRegBit (
+  IN USB2_HC_DEV          *Ehc,
+  IN UINT32               Offset,
+  IN UINT32               Bit
+  );
+
+/**
+  Clear one bit of the operational register while keeping other bits.
+
+  @param  Ehc          The EHCI device.
+  @param  Offset       The offset of the operational register.
+  @param  Bit          The bit mask of the register to clear.
+
+**/
+VOID
+EhcClearOpRegBit (
+  IN USB2_HC_DEV          *Ehc,
+  IN UINT32               Offset,
+  IN UINT32               Bit
+  );
 
 /**
   Add support for UEFI Over Legacy (UoL) feature, stop