thunderbolt: Handle hotplug events

We receive a plug event callback whenever a thunderbolt device is added
or removed. This patch fills in the tb_handle_hotplug method and starts
reacting to these events by adding/removing switches from the hierarchy.

Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 70a66fe..661f182 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -20,6 +20,7 @@
 	struct tb_port *ports;
 	struct tb *tb;
 	int cap_plug_events; /* offset, zero if not found */
+	bool is_unplugged; /* unplugged, will go away */
 };
 
 /**
@@ -160,6 +161,8 @@
 
 struct tb_switch *tb_switch_alloc(struct tb *tb, u64 route);
 void tb_switch_free(struct tb_switch *sw);
+void tb_sw_set_unpplugged(struct tb_switch *sw);
+struct tb_switch *get_switch_at_route(struct tb_switch *sw, u64 route);
 
 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);