make the dma interface useable.

make it so that pio devices must respond with some delay.

dev/io_device.cc:
    don't forget to include dma_interface.hh so we could use it.
dev/io_device.hh:
    the generic BusInterface isn't enough for doing DMA
    we need the actual DMAInterface

--HG--
extra : convert_revision : 70298d33c8520a3f4ad11aa600825a8cec7e44bf

dev/io_device.cc

@@ -28,6 +28,7 @@
 
 #include "dev/io_device.hh"
 #include "mem/bus/base_interface.hh"
+#include "mem/bus/dma_interface.hh"
 
 PioDevice::PioDevice(const std::string &name)
     : FunctionalMemory(name), pioInterface(NULL)

dev/io_device.hh

@@ -34,6 +34,7 @@
 class BaseInterface;
 class Bus;
 class HierParams;
+template <class Bus> class DMAInterface;
 
 class PioDevice : public FunctionalMemory
 {
@@ -48,7 +49,7 @@ class PioDevice : public FunctionalMemory
 class DmaDevice : public PioDevice
 {
   protected:
-    BaseInterface *dmaInterface;
+    DMAInterface<Bus> *dmaInterface;
 
   public:
     DmaDevice(const std::string &name);