diff --git a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
index acc106bcf4..f4ee9e4c5e 100644
--- a/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
+++ b/ArmPkg/Library/ArmDmaLib/ArmDmaLib.c
@@ -142,7 +142,7 @@ DmaMap (
         CopyMem (Buffer, HostAddress, *NumberOfBytes);
       }
 
-      *DeviceAddress = HostToDeviceAddress (ConvertToPhysicalAddress ((UINTN)Buffer));
+      *DeviceAddress = HostToDeviceAddress (ConvertToPhysicalAddress (Buffer));
       Map->BufferAddress = Buffer;
     } else {
       Map->DoubleBuffer  = FALSE;