thunderbolt: Add DP OUT resource when DP tunnel is discovered

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2107603
Upstream Status: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b60e31bf18a7064032dbcb73dcb5b58f8a00a110

commit b60e31b
Author: Sanjay R Mehta <sanju.mehta@amd.com>
Date: Thu, 4 Aug 2022 05:48:38 -0500

  If the boot firmware implements a connection manager of its own it may
  create a DisplayPort tunnel and will be handed off to Linux connection
  manager, but the DP OUT resource is not saved in the dp_resource list.

  This patch adds tunnelled DP OUT port to the dp_resource list once the
  DP tunnel is discovered.

  Signed-off-by: Sanjay R Mehta <sanju.mehta@amd.com>
  Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
  Tested-by: Renjith Pananchikkal <Renjith.Pananchikkal@amd.com>
  Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Signed-off-by: Desnes Nunes <desnesn@redhat.com>

Author: Desnes Nunes

drivers/thunderbolt/tb.c

@@ -105,6 +105,32 @@ static void tb_remove_dp_resources(struct tb_switch *sw)
 	}
 }
 
+static void tb_discover_dp_resource(struct tb *tb, struct tb_port *port)
+{
+	struct tb_cm *tcm = tb_priv(tb);
+	struct tb_port *p;
+
+	list_for_each_entry(p, &tcm->dp_resources, list) {
+		if (p == port)
+			return;
+	}
+
+	tb_port_dbg(port, "DP %s resource available discovered\n",
+		    tb_port_is_dpin(port) ? "IN" : "OUT");
+	list_add_tail(&port->list, &tcm->dp_resources);
+}
+
+static void tb_discover_dp_resources(struct tb *tb)
+{
+	struct tb_cm *tcm = tb_priv(tb);
+	struct tb_tunnel *tunnel;
+
+	list_for_each_entry(tunnel, &tcm->tunnel_list, list) {
+		if (tb_tunnel_is_dp(tunnel))
+			tb_discover_dp_resource(tb, tunnel->dst_port);
+	}
+}
+
 static void tb_switch_discover_tunnels(struct tb_switch *sw,
 				       struct list_head *list,
 				       bool alloc_hopids)
@@ -1446,6 +1472,8 @@ static int tb_start(struct tb *tb)
 	tb_scan_switch(tb->root_switch);
 	/* Find out tunnels created by the boot firmware */
 	tb_discover_tunnels(tb);
+	/* Add DP resources from the DP tunnels created by the boot firmware */
+	tb_discover_dp_resources(tb);
 	/*
 	 * If the boot firmware did not create USB 3.x tunnels create them
 	 * now for the whole topology.