1 files changed, 16 insertions, 19 deletions
diff --git a/hw/usb.c b/hw/usb.c
index a091e4eafc..fa90204c5e 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -27,26 +27,23 @@
 #include "usb.h"
 #include "iov.h"
 
-void usb_attach(USBPort *port, USBDevice *dev)
+void usb_attach(USBPort *port)
 {
-    if (dev != NULL) {
-        /* attach */
-        if (port->dev) {
-            usb_attach(port, NULL);
-        }
-        dev->port = port;
-        port->dev = dev;
-        port->ops->attach(port);
-        usb_send_msg(dev, USB_MSG_ATTACH);
-    } else {
-        /* detach */
-        dev = port->dev;
-        assert(dev);
-        port->ops->detach(port);
-        usb_send_msg(dev, USB_MSG_DETACH);
-        dev->port = NULL;
-        port->dev = NULL;
-    }
+    USBDevice *dev = port->dev;
+
+    assert(dev != NULL);
+    assert(dev->attached);
+    port->ops->attach(port);
+    usb_send_msg(dev, USB_MSG_ATTACH);
+}
+
+void usb_detach(USBPort *port)
+{
+    USBDevice *dev = port->dev;
+
+    assert(dev != NULL);
+    port->ops->detach(port);
+    usb_send_msg(dev, USB_MSG_DETACH);
 }
 
 void usb_wakeup(USBDevice *dev)