[PATCH 18/28] thunderbolt: Scan only valid NULL adapter ports in hotplug

[Mika Westerberg <mika.westerberg@linux.intel.com>]

The only way to expand Thunderbolt topology is through the NULL adapter
ports (typically ports 1, 2, 3 and 4). There is no point handling
Thunderbolt hotplug events on any other port.

Add a helper function (tb_port_is_null()) that can be used to determine
if the port is NULL port, and use it in software connection manager code
when hotplug event is handled.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb.c | 10 ++++++----
 drivers/thunderbolt/tb.h |  5 +++++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index c2e102f55ee0..1dcdf619d0f1 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -344,10 +344,12 @@ static void tb_handle_hotplug(struct work_struct *work)
 		tb_port_info(port,
 			     "got plug event for connected port, ignoring\n");
 	} else {
-		tb_port_info(port, "hotplug: scanning\n");
-		tb_scan_port(port);
-		if (!port->remote)
-			tb_port_info(port, "hotplug: no switch found\n");
+		if (tb_port_is_null(port)) {
+			tb_port_info(port, "hotplug: scanning\n");
+			tb_scan_port(port);
+			if (!port->remote)
+				tb_port_info(port, "hotplug: no switch found\n");
+		}
 	}
 out:
 	mutex_unlock(&tb->lock);
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index f476c3f0cb9a..b3a422ab4b4e 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -287,6 +287,11 @@ static inline struct tb_port *tb_port_at(u64 route, struct tb_switch *sw)
 	return &sw->ports[port];
 }
 
+static inline bool tb_port_is_null(const struct tb_port *port)
+{
+	return port->port && port->config.type == TB_TYPE_PORT;
+}
+
 static inline int tb_sw_read(struct tb_switch *sw, void *buffer,
 			     enum tb_cfg_space space, u32 offset, u32 length)
 {
-- 
2.20.1