thunderbolt: Handle rejected Thunderbolt devices

The ICM firmware rejects devices if the maximum topology limit is
exceeded (more than 6 devices are connected). If that happens just log a
message to the kernel message buffer and bail out.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/thunderbolt/icm.c

@@ -410,6 +410,12 @@ icm_fr_device_connected(struct tb *tb, const struct icm_pkg_header *hdr)
 		ICM_LINK_INFO_DEPTH_SHIFT;
 	authorized = pkg->link_info & ICM_LINK_INFO_APPROVED;
 
+	if (pkg->link_info & ICM_LINK_INFO_REJECTED) {
+		tb_info(tb, "switch at %u.%u was rejected by ICM firmware because topology limit exceeded\n",
+			link, depth);
+		return;
+	}
+
 	ret = icm->get_route(tb, link, depth, &route);
 	if (ret) {
 		tb_err(tb, "failed to find route string for switch at %u.%u\n",

drivers/thunderbolt/tb_msgs.h

@@ -176,6 +176,7 @@ struct icm_fr_event_device_connected {
 #define ICM_LINK_INFO_DEPTH_SHIFT	4
 #define ICM_LINK_INFO_DEPTH_MASK	GENMASK(7, 4)
 #define ICM_LINK_INFO_APPROVED		BIT(8)
+#define ICM_LINK_INFO_REJECTED		BIT(9)
 
 struct icm_fr_pkg_approve_device {
 	struct icm_pkg_header hdr;