[PATCH v8 36/36] media: subdev: add v4l2_routing_simple_verify() helper

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

Add a helper for verifying routing for the common case of
non-overlapping 1-to-1 streams.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 24 ++++++++++++++++++++++++
 include/media/v4l2-subdev.h           | 14 ++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 83fa87e88bce..e3a7793157db 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1572,3 +1572,27 @@ int v4l2_subdev_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_get_fmt);
+
+int v4l2_routing_simple_verify(const struct v4l2_subdev_krouting *routing)
+{
+	unsigned int i, j;
+
+	for (i = 0; i < routing->num_routes; ++i) {
+		const struct v4l2_subdev_route *route = &routing->routes[i];
+
+		for (j = i + 1; j < routing->num_routes; ++j) {
+			const struct v4l2_subdev_route *r = &routing->routes[j];
+
+			if (route->sink_pad == r->sink_pad &&
+			    route->sink_stream == r->sink_stream)
+				return -EINVAL;
+
+			if (route->source_pad == r->source_pad &&
+			    route->source_stream == r->source_stream)
+				return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_routing_simple_verify);
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 3f72c500ff6e..476d797ecc68 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1562,4 +1562,18 @@ v4l2_state_get_opposite_stream_format(struct v4l2_subdev_state *state, u32 pad,
 int v4l2_subdev_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
 			struct v4l2_subdev_format *format);
 
+/**
+ * v4l2_routing_simple_verify() - Verify that all streams are non-overlapping
+ * 				  1-to-1 streams
+ * @routing: routing to verify
+ *
+ * This verifies that the given routing contains only non-overlapping 1-to-1
+ * streams. In other words, no two streams have the same source or sink
+ * stream ID on a single pad. This is the most common case of routing
+ * supported by devices.
+ *
+ * Returns 0 on success, error value otherwise.
+ */
+int v4l2_routing_simple_verify(const struct v4l2_subdev_krouting *routing);
+
 #endif
-- 
2.25.1