Revert "EhciDxe: Use common buffer for AsyncInterruptTransfer"

There is concern at the thread
https://lists.01.org/pipermail/edk2-devel/2018-November/031951.html.
And the time point is a little sensitive as it is near edk2-stable201811.

This reverts commit 0cd6452503.

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

MdeModulePkg/Bus/Pci/EhciDxe/EhciSched.c

@@ -778,6 +778,7 @@ EhciDelAsyncIntTransfer (
       EhcUnlinkQhFromPeriod (Ehc, Urb->Qh);
       RemoveEntryList (&Urb->UrbList);
 
+      gBS->FreePool (Urb->Data);
       EhcFreeUrb (Ehc, Urb);
       return EFI_SUCCESS;
     }
@@ -808,6 +809,7 @@ EhciDelAllAsyncIntTransfers (
     EhcUnlinkQhFromPeriod (Ehc, Urb->Qh);
     RemoveEntryList (&Urb->UrbList);
 
+    gBS->FreePool (Urb->Data);
     EhcFreeUrb (Ehc, Urb);
   }
 }
@@ -846,8 +848,16 @@ EhciInsertAsyncIntTransfer (
   IN UINTN                              Interval
   )
 {
+  VOID      *Data;
   URB       *Urb;
 
+  Data = AllocatePool (DataLen);
+
+  if (Data == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a: failed to allocate buffer\n", __FUNCTION__));
+    return NULL;
+  }
+
   Urb = EhcCreateUrb (
           Ehc,
           DevAddr,
@@ -858,8 +868,7 @@ EhciInsertAsyncIntTransfer (
           Hub,
           EHC_INT_TRANSFER_ASYNC,
           NULL,
-          TRUE,
-          NULL,
+          Data,
           DataLen,
           Callback,
           Context,
@@ -868,6 +877,7 @@ EhciInsertAsyncIntTransfer (
 
   if (Urb == NULL) {
     DEBUG ((DEBUG_ERROR, "%a: failed to create URB\n", __FUNCTION__));
+    gBS->FreePool (Data);
     return NULL;
   }
 
@@ -881,6 +891,60 @@ EhciInsertAsyncIntTransfer (
   return Urb;
 }
 
+/**
+  Flush data from PCI controller specific address to mapped system
+  memory address.
+
+  @param  Ehc                The EHCI device.
+  @param  Urb                The URB to unmap.
+
+  @retval EFI_SUCCESS        Success to flush data to mapped system memory.
+  @retval EFI_DEVICE_ERROR   Fail to flush data to mapped system memory.
+
+**/
+EFI_STATUS
+EhcFlushAsyncIntMap (
+  IN  USB2_HC_DEV         *Ehc,
+  IN  URB                 *Urb
+  )
+{
+  EFI_STATUS                    Status;
+  EFI_PHYSICAL_ADDRESS          PhyAddr;
+  EFI_PCI_IO_PROTOCOL_OPERATION MapOp;
+  EFI_PCI_IO_PROTOCOL           *PciIo;
+  UINTN                         Len;
+  VOID                          *Map;
+
+  PciIo = Ehc->PciIo;
+  Len   = Urb->DataLen;
+
+  if (Urb->Ep.Direction == EfiUsbDataIn) {
+    MapOp = EfiPciIoOperationBusMasterWrite;
+  } else {
+    MapOp = EfiPciIoOperationBusMasterRead;
+  }
+
+  Status = PciIo->Unmap (PciIo, Urb->DataMap);
+  if (EFI_ERROR (Status)) {
+    goto ON_ERROR;
+  }
+
+  Urb->DataMap = NULL;
+
+  Status = PciIo->Map (PciIo, MapOp, Urb->Data, &Len, &PhyAddr, &Map);
+  if (EFI_ERROR (Status) || (Len != Urb->DataLen)) {
+    goto ON_ERROR;
+  }
+
+  Urb->DataPhy  = (VOID *) ((UINTN) PhyAddr);
+  Urb->DataMap  = Map;
+  return EFI_SUCCESS;
+
+ON_ERROR:
+  return EFI_DEVICE_ERROR;
+}
+
+
 /**
   Update the queue head for next round of asynchronous transfer.
 
@@ -986,6 +1050,7 @@ EhcMonitorAsyncRequests (
   BOOLEAN                 Finished;
   UINT8                   *ProcBuf;
   URB                     *Urb;
+  EFI_STATUS              Status;
 
   OldTpl  = gBS->RaiseTPL (EHC_TPL);
   Ehc     = (USB2_HC_DEV *) Context;
@@ -1003,6 +1068,15 @@ EhcMonitorAsyncRequests (
       continue;
     }
 
+    //
+    // Flush any PCI posted write transactions from a PCI host
+    // bridge to system memory.
+    //
+    Status = EhcFlushAsyncIntMap (Ehc, Urb);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((EFI_D_ERROR, "EhcMonitorAsyncRequests: Fail to Flush AsyncInt Mapped Memeory\n"));
+    }
+
     //
     // Allocate a buffer then copy the transferred data for user.
     // If failed to allocate the buffer, update the URB for next