Index: uspace/lib/drv/include/usb_iface.h
===================================================================
--- uspace/lib/drv/include/usb_iface.h	(revision 9d15d1bd38a7b5422ec653dd5c87ec3d9cb353b9)
+++ uspace/lib/drv/include/usb_iface.h	(revision 3969a425b60997df437e943e91d861b21c393972)
@@ -66,4 +66,12 @@
     usb_direction_t, size_t, unsigned);
 int usb_unregister_endpoint(async_exch_t *, usb_endpoint_t, usb_direction_t);
+int usb_read(async_exch_t *, usb_endpoint_t, uint64_t, void *, size_t, size_t *);
+int usb_write(async_exch_t *, usb_endpoint_t, uint64_t, const void *, size_t);
+
+/** Callback for outgoing transfer. */
+typedef void (*usbhc_iface_transfer_out_callback_t)(int, void *);
+
+/** Callback for incoming transfer. */
+typedef void (*usbhc_iface_transfer_in_callback_t)(int, size_t, void *);
 
 /** USB device communication interface. */
@@ -83,4 +91,8 @@
 	int (*unregister_endpoint)(ddf_fun_t *, usb_endpoint_t,
 	    usb_direction_t);
+	int (*read)(ddf_fun_t *, usb_endpoint_t, uint64_t, uint8_t *, size_t,
+	    usbhc_iface_transfer_in_callback_t, void *);
+	int (*write)(ddf_fun_t *, usb_endpoint_t, uint64_t, const uint8_t *,
+	    size_t, usbhc_iface_transfer_out_callback_t, void *);
 } usb_iface_t;