thunderbolt: Assign remote for both ports in case of dual link

Currently the driver only assigns remote port for the primary port if in
case of dual link. This makes things such as walking from one port to
another more complex than necessary because the code needs to change
from secondary to primary port if the path that is established is
created using secondary links.

In order to always assign both remote pointers we need to prevent the
scanning code from following the secondary link. Failing to do that
might cause problems as the same switch may be enumerated twice (or
removed in case of unplug). Handle that properly by introducing a new
function tb_port_has_remote() that returns true only for the primary
port. We also update tb_is_upstream_port() to support both dual link
ports, make it take const port pointer and move it below
tb_upstream_port() to keep similar functions close.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 36dad0a00ac2..0485f4ef9a62 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -47,7 +47,9 @@ static void tb_scan_switch(struct tb_switch *sw)
  */
 static void tb_scan_port(struct tb_port *port)
 {
+	struct tb_port *upstream_port;
 	struct tb_switch *sw;
+
 	if (tb_is_upstream_port(port))
 		return;
 	if (port->config.type != TB_TYPE_PORT)
@@ -80,8 +82,15 @@ static void tb_scan_port(struct tb_port *port)
 		return;
 	}
 
-	port->remote = tb_upstream_port(sw);
-	tb_upstream_port(sw)->remote = port;
+	/* Link the switches using both links if available */
+	upstream_port = tb_upstream_port(sw);
+	port->remote = upstream_port;
+	upstream_port->remote = port;
+	if (port->dual_link_port && upstream_port->dual_link_port) {
+		port->dual_link_port->remote = upstream_port->dual_link_port;
+		upstream_port->dual_link_port->remote = port->dual_link_port;
+	}
+
 	tb_scan_switch(sw);
 }
 
@@ -111,13 +120,15 @@ static void tb_free_unplugged_children(struct tb_switch *sw)
 	int i;
 	for (i = 1; i <= sw->config.max_port_number; i++) {
 		struct tb_port *port = &sw->ports[i];
-		if (tb_is_upstream_port(port))
-			continue;
-		if (!port->remote)
+
+		if (!tb_port_has_remote(port))
 			continue;
+
 		if (port->remote->sw->is_unplugged) {
 			tb_switch_remove(port->remote->sw);
 			port->remote = NULL;
+			if (port->dual_link_port)
+				port->dual_link_port->remote = NULL;
 		} else {
 			tb_free_unplugged_children(port->remote->sw);
 		}
@@ -273,18 +284,19 @@ static void tb_handle_hotplug(struct work_struct *work)
 	}
 	port = &sw->ports[ev->port];
 	if (tb_is_upstream_port(port)) {
-		tb_warn(tb,
-			"hotplug event for upstream port %llx:%x (unplug: %d)\n",
-			ev->route, ev->port, ev->unplug);
+		tb_dbg(tb, "hotplug event for upstream port %llx:%x (unplug: %d)\n",
+		       ev->route, ev->port, ev->unplug);
 		goto put_sw;
 	}
 	if (ev->unplug) {
-		if (port->remote) {
+		if (tb_port_has_remote(port)) {
 			tb_port_info(port, "unplugged\n");
 			tb_sw_set_unplugged(port->remote->sw);
 			tb_free_invalid_tunnels(tb);
 			tb_switch_remove(port->remote->sw);
 			port->remote = NULL;
+			if (port->dual_link_port)
+				port->dual_link_port->remote = NULL;
 		} else {
 			tb_port_info(port,
 				     "got unplug event for disconnected port, ignoring\n");