media: rkisp1: isp: Disallow multiple active sources

The ISP supports multiple source subdevs, but can only capture from a
single one at a time. The source is selected through link setup. The
driver finds the active source in its .s_stream() handler using the
media_entity_remote_pad() function. This fails to reject invalid
configurations with multiple active sources. Fix it by using the
media_pad_remote_pad_unique() helper instead, and inline
rkisp1_isp_get_source() in rkisp1_isp_s_stream() as the function is
small and has a single caller.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Dafna Hirschfeld <dafna@fastmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
index 37623b73b1d916dab761eb0b933f2ab62d750fd7..d7e2802d11f5d6990f1a9bf79b305c43e8112ae0 100644 (file)
--- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
+++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
@@ -58,20 +58,6 @@
  * Helpers
  */
 
-static struct v4l2_subdev *rkisp1_isp_get_source(struct v4l2_subdev *sd)
-{
-       struct media_pad *local, *remote;
-       struct media_entity *sensor_me;
-
-       local = &sd->entity.pads[RKISP1_ISP_PAD_SINK_VIDEO];
-       remote = media_pad_remote_pad_first(local);
-       if (!remote)
-               return NULL;
-
-       sensor_me = remote->entity;
-       return media_entity_to_v4l2_subdev(sensor_me);
-}
-
 static struct v4l2_mbus_framefmt *
 rkisp1_isp_get_pad_fmt(struct rkisp1_isp *isp,
                       struct v4l2_subdev_state *sd_state,
@@ -743,6 +729,8 @@ static int rkisp1_isp_s_stream(struct v4l2_subdev *sd, int enable)
        struct rkisp1_isp *isp = to_rkisp1_isp(sd);
        struct rkisp1_device *rkisp1 = isp->rkisp1;
        const struct rkisp1_sensor_async *asd;
+       struct media_pad *source_pad;
+       struct media_pad *sink_pad;
        int ret;
 
        if (!enable) {
@@ -754,10 +742,18 @@ static int rkisp1_isp_s_stream(struct v4l2_subdev *sd, int enable)
                return 0;
        }
 
-       rkisp1->source = rkisp1_isp_get_source(sd);
+       sink_pad = &isp->pads[RKISP1_ISP_PAD_SINK_VIDEO];
+       source_pad = media_pad_remote_pad_unique(sink_pad);
+       if (IS_ERR(source_pad)) {
+               dev_dbg(rkisp1->dev, "Failed to get source for ISP: %ld\n",
+                       PTR_ERR(source_pad));
+               return -EPIPE;
+       }
+
+       rkisp1->source = media_entity_to_v4l2_subdev(source_pad->entity);
        if (!rkisp1->source) {
-               dev_warn(rkisp1->dev, "No link between isp and source\n");
-               return -ENODEV;
+               /* This should really not happen, so is not worth a message. */
+               return -EPIPE;
        }
 
        asd = container_of(rkisp1->source->asd, struct rkisp1_sensor_async,