gpu: host1x: Show number of pending waiters in debugfs

Show the number of pending waiters in the debugfs status file.
This is useful for testing to verify that waiters do not leak
or accumulate incorrectly.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/debug.c

@@ -69,6 +69,7 @@ static int show_channel(struct host1x_channel *ch, void *data, bool show_fifo)
 
 static void show_syncpts(struct host1x *m, struct output *o)
 {
+	struct list_head *pos;
 	unsigned int i;
 
 	host1x_debug_output(o, "---- syncpts ----\n");
@@ -76,12 +77,19 @@ static void show_syncpts(struct host1x *m, struct output *o)
 	for (i = 0; i < host1x_syncpt_nb_pts(m); i++) {
 		u32 max = host1x_syncpt_read_max(m->syncpt + i);
 		u32 min = host1x_syncpt_load(m->syncpt + i);
+		unsigned int waiters = 0;
 
-		if (!min && !max)
+		spin_lock(&m->syncpt[i].intr.lock);
+		list_for_each(pos, &m->syncpt[i].intr.wait_head)
+			waiters++;
+		spin_unlock(&m->syncpt[i].intr.lock);
+
+		if (!min && !max && !waiters)
 			continue;
 
-		host1x_debug_output(o, "id %u (%s) min %d max %d\n",
-				    i, m->syncpt[i].name, min, max);
+		host1x_debug_output(o,
+				    "id %u (%s) min %d max %d (%d waiters)\n",
+				    i, m->syncpt[i].name, min, max, waiters);
 	}
 
 	for (i = 0; i < host1x_syncpt_nb_bases(m); i++) {