[media] v4l: Implement v4l2_subdev_link_validate()

v4l2_subdev_link_validate() is the default op for validating a link. In V4L2
subdev context, it is used to call a pad op which performs the proper link
check without much extra work.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 493ffd1b1cf5f98d5f7486ffa461a78fae3e7dff..fe53177f0d3cdc815bbade9a6e0cf29e5ad2360d 100644 (file)
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -316,6 +316,18 @@ If the subdev driver intends to process video and integrate with the media
 framework, it must implement format related functionality using
 v4l2_subdev_pad_ops instead of v4l2_subdev_video_ops.
 
+In that case, the subdev driver may set the link_validate field to provide
+its own link validation function. The link validation function is called for
+every link in the pipeline where both of the ends of the links are V4L2
+sub-devices. The driver is still responsible for validating the correctness
+of the format configuration between sub-devices and video nodes.
+
+If link_validate op is not set, the default function
+v4l2_subdev_link_validate_default() is used instead. This function ensures
+that width, height and the media bus pixel code are equal on both source and
+sink of the link. Subdev drivers are also free to use this function to
+perform the checks mentioned above in addition to their own checks.
+
 A device (bridge) driver needs to register the v4l2_subdev with the
 v4l2_device:
 

diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
index 268d80584101d8321bbf3deeed550b3ed57314d8..db6e859b93d4832a6420ca6d3d111d24b13164df 100644 (file)
--- a/drivers/media/video/v4l2-subdev.c
+++ b/drivers/media/video/v4l2-subdev.c
@@ -387,6 +387,70 @@ const struct v4l2_file_operations v4l2_subdev_fops = {
        .poll = subdev_poll,
 };
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
+                                     struct media_link *link,
+                                     struct v4l2_subdev_format *source_fmt,
+                                     struct v4l2_subdev_format *sink_fmt)
+{
+       if (source_fmt->format.width != sink_fmt->format.width
+           || source_fmt->format.height != sink_fmt->format.height
+           || source_fmt->format.code != sink_fmt->format.code)
+               return -EINVAL;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate_default);
+
+static int
+v4l2_subdev_link_validate_get_format(struct media_pad *pad,
+                                    struct v4l2_subdev_format *fmt)
+{
+       switch (media_entity_type(pad->entity)) {
+       case MEDIA_ENT_T_V4L2_SUBDEV:
+               fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
+               fmt->pad = pad->index;
+               return v4l2_subdev_call(media_entity_to_v4l2_subdev(
+                                               pad->entity),
+                                       pad, get_fmt, NULL, fmt);
+       default:
+               WARN(1, "Driver bug! Wrong media entity type %d, entity %s\n",
+                    media_entity_type(pad->entity), pad->entity->name);
+               /* Fall through */
+       case MEDIA_ENT_T_DEVNODE_V4L:
+               return -EINVAL;
+       }
+}
+
+int v4l2_subdev_link_validate(struct media_link *link)
+{
+       struct v4l2_subdev *sink;
+       struct v4l2_subdev_format sink_fmt, source_fmt;
+       int rval;
+
+       rval = v4l2_subdev_link_validate_get_format(
+               link->source, &source_fmt);
+       if (rval < 0)
+               return 0;
+
+       rval = v4l2_subdev_link_validate_get_format(
+               link->sink, &sink_fmt);
+       if (rval < 0)
+               return 0;
+
+       sink = media_entity_to_v4l2_subdev(link->sink->entity);
+
+       rval = v4l2_subdev_call(sink, pad, link_validate, link,
+                               &source_fmt, &sink_fmt);
+       if (rval != -ENOIOCTLCMD)
+               return rval;
+
+       return v4l2_subdev_link_validate_default(
+               sink, link, &source_fmt, &sink_fmt);
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
+#endif /* CONFIG_MEDIA_CONTROLLER */
+
 void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
 {
        INIT_LIST_HEAD(&sd->list);

diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 7e850355a6f0c1ad4f6e350b57154051816b34b2..1c2318b15bd2ecc1d4150dfc0a1ef1dc67295d30 100644 (file)
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -470,6 +470,11 @@ struct v4l2_subdev_pad_ops {
                             struct v4l2_subdev_selection *sel);
        int (*set_selection)(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh,
                             struct v4l2_subdev_selection *sel);
+#ifdef CONFIG_MEDIA_CONTROLLER
+       int (*link_validate)(struct v4l2_subdev *sd, struct media_link *link,
+                            struct v4l2_subdev_format *source_fmt,
+                            struct v4l2_subdev_format *sink_fmt);
+#endif /* CONFIG_MEDIA_CONTROLLER */
 };
 
 struct v4l2_subdev_ops {
@@ -602,6 +607,13 @@ static inline void *v4l2_get_subdev_hostdata(const struct v4l2_subdev *sd)
        return sd->host_priv;
 }
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
+                                     struct media_link *link,
+                                     struct v4l2_subdev_format *source_fmt,
+                                     struct v4l2_subdev_format *sink_fmt);
+int v4l2_subdev_link_validate(struct media_link *link);
+#endif /* CONFIG_MEDIA_CONTROLLER */
 void v4l2_subdev_init(struct v4l2_subdev *sd,
                      const struct v4l2_subdev_ops *ops);