[PATCH v15 16/19] media: v4l2-subdev: Add v4l2_subdev_state_xlate_streams() helper

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

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Add a helper function to translate streams between two pads of a subdev,
using the subdev's internal routing table.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 26 ++++++++++++++++++++++++++
 include/media/v4l2-subdev.h           | 23 +++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 7fabb2079b3f..cc8666c5069b 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1589,6 +1589,32 @@ v4l2_subdev_state_get_opposite_stream_format(struct v4l2_subdev_state *state,
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_state_get_opposite_stream_format);
 
+u64 v4l2_subdev_state_xlate_streams(const struct v4l2_subdev_state *state,
+				    u32 pad0, u32 pad1, u64 *streams)
+{
+	const struct v4l2_subdev_krouting *routing = &state->routing;
+	struct v4l2_subdev_route *route;
+	u64 streams0 = 0;
+	u64 streams1 = 0;
+
+	for_each_active_route(routing, route) {
+		if (route->sink_pad == pad0 && route->source_pad == pad1 &&
+		    (*streams & BIT_ULL(route->sink_stream))) {
+			streams0 |= BIT_ULL(route->sink_stream);
+			streams1 |= BIT_ULL(route->source_stream);
+		}
+		if (route->source_pad == pad0 && route->sink_pad == pad1 &&
+		    (*streams & BIT_ULL(route->source_stream))) {
+			streams0 |= BIT_ULL(route->source_stream);
+			streams1 |= BIT_ULL(route->sink_stream);
+		}
+	}
+
+	*streams = streams0;
+	return streams1;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_state_xlate_streams);
+
 int v4l2_subdev_routing_validate(struct v4l2_subdev *sd,
 				 const struct v4l2_subdev_krouting *routing,
 				 enum v4l2_subdev_routing_restriction disallow)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 6661887536bf..8c002d65e08e 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1579,6 +1579,29 @@ struct v4l2_mbus_framefmt *
 v4l2_subdev_state_get_opposite_stream_format(struct v4l2_subdev_state *state,
 					     u32 pad, u32 stream);
 
+/**
+ * v4l2_subdev_state_xlate_streams() - Translate streams from one pad to another
+ *
+ * @state: Subdevice state
+ * @pad0: The first pad
+ * @pad1: The second pad
+ * @streams: Streams bitmask on the first pad
+ *
+ * Streams on sink pads of a subdev are routed to source pads as expressed in
+ * the subdev state routing table. Stream numbers don't necessarily match on
+ * the sink and source side of a route. This function translates stream numbers
+ * on @pad0, expressed as a bitmask in @streams, to the corresponding streams
+ * on @pad1 using the routing table from the @state. It returns the stream mask
+ * on @pad1, and updates @streams with the streams that have been found in the
+ * routing table.
+ *
+ * @pad0 and @pad1 must be a sink and a source, in any order.
+ *
+ * Return: The bitmask of streams of @pad1 that are routed to @streams on @pad0.
+ */
+u64 v4l2_subdev_state_xlate_streams(const struct v4l2_subdev_state *state,
+				    u32 pad0, u32 pad1, u64 *streams);
+
 /**
  * enum v4l2_subdev_routing_restriction - Subdevice internal routing restrictions
  *
-- 
2.34.1