qdev: introduce reset call back for qbus level

and make it called via qbus_reset_all().
The qbus reset callback will be used by pci bus reset.
Signed-off-by: NIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/qdev.c

@@ -314,9 +314,17 @@ BusState *sysbus_get_default(void)
     return main_system_bus;
 }
 
+static int qbus_reset_one(BusState *bus, void *opaque)
+{
+    if (bus->info->reset) {
+        return bus->info->reset(bus);
+    }
+    return 0;
+}
+
 void qbus_reset_all(BusState *bus)
 {
-    qbus_walk_children(bus, qdev_reset_one, NULL, NULL);
+    qbus_walk_children(bus, qdev_reset_one, qbus_reset_one, NULL);
 }
 
 /* can be used as ->unplug() callback for the simple cases */

hw/qdev.h

@@ -49,12 +49,14 @@ struct DeviceState {
 
 typedef void (*bus_dev_printfn)(Monitor *mon, DeviceState *dev, int indent);
 typedef char *(*bus_get_dev_path)(DeviceState *dev);
+typedef int (qbus_resetfn)(BusState *bus);
 
 struct BusInfo {
     const char *name;
     size_t size;
     bus_dev_printfn print_dev;
     bus_get_dev_path get_dev_path;
+    qbus_resetfn *reset;
     Property *props;
 };