media: v4l2-mc: add v4l2_create_fwnode_links helpers

Add functions to create media links between source and sink subdevices,
based on the fwnode endpoint connections between them:

v4l2_create_fwnode_links_to_pad() - create links from a source subdev to
                                    a single sink pad based on fwnode
                                    endpoint connections.

v4l2_create_fwnode_links() - create all links from a source to sink subdev
                             based on fwnode endpoint connections.

These functions can be used in a sink's v4l2-async notifier subdev
bound callback to make the links from the bound subdev.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
index 0fffdd3..ba2f2b8 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -309,6 +309,101 @@ int v4l_vb2q_enable_media_source(struct vb2_queue *q)
 }
 EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
 
+int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
+                                   struct media_pad *sink)
+{
+       struct fwnode_handle *endpoint;
+       struct v4l2_subdev *sink_sd;
+
+       if (!(sink->flags & MEDIA_PAD_FL_SINK) ||
+           !is_media_entity_v4l2_subdev(sink->entity))
+               return -EINVAL;
+
+       sink_sd = media_entity_to_v4l2_subdev(sink->entity);
+
+       fwnode_graph_for_each_endpoint(dev_fwnode(src_sd->dev), endpoint) {
+               struct fwnode_handle *remote_ep;
+               int src_idx, sink_idx, ret;
+               struct media_pad *src;
+
+               src_idx = media_entity_get_fwnode_pad(&src_sd->entity,
+                                                     endpoint,
+                                                     MEDIA_PAD_FL_SOURCE);
+               if (src_idx < 0)
+                       continue;
+
+               remote_ep = fwnode_graph_get_remote_endpoint(endpoint);
+               if (!remote_ep)
+                       continue;
+
+               /*
+                * ask the sink to verify it owns the remote endpoint,
+                * and translate to a sink pad.
+                */
+               sink_idx = media_entity_get_fwnode_pad(&sink_sd->entity,
+                                                      remote_ep,
+                                                      MEDIA_PAD_FL_SINK);
+               fwnode_handle_put(remote_ep);
+
+               if (sink_idx < 0 || sink_idx != sink->index)
+                       continue;
+
+               /*
+                * the source endpoint corresponds to one of its source pads,
+                * the source endpoint connects to an endpoint at the sink
+                * entity, and the sink endpoint corresponds to the sink
+                * pad requested, so we have found an endpoint connection
+                * that works, create the media link for it.
+                */
+
+               src = &src_sd->entity.pads[src_idx];
+
+               /* skip if link already exists */
+               if (media_entity_find_link(src, sink))
+                       continue;
+
+               dev_dbg(sink_sd->dev, "creating link %s:%d -> %s:%d\n",
+                       src_sd->entity.name, src_idx,
+                       sink_sd->entity.name, sink_idx);
+
+               ret = media_create_pad_link(&src_sd->entity, src_idx,
+                                           &sink_sd->entity, sink_idx, 0);
+               if (ret) {
+                       dev_err(sink_sd->dev,
+                               "link %s:%d -> %s:%d failed with %d\n",
+                               src_sd->entity.name, src_idx,
+                               sink_sd->entity.name, sink_idx, ret);
+
+                       fwnode_handle_put(endpoint);
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_create_fwnode_links_to_pad);
+
+int v4l2_create_fwnode_links(struct v4l2_subdev *src_sd,
+                            struct v4l2_subdev *sink_sd)
+{
+       unsigned int i;
+
+       for (i = 0; i < sink_sd->entity.num_pads; i++) {
+               struct media_pad *pad = &sink_sd->entity.pads[i];
+               int ret;
+
+               if (!(pad->flags & MEDIA_PAD_FL_SINK))
+                       continue;
+
+               ret = v4l2_create_fwnode_links_to_pad(src_sd, pad);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_create_fwnode_links);
+
 /* -----------------------------------------------------------------------------
  * Pipeline power management
  *

diff --git a/include/media/v4l2-mc.h b/include/media/v4l2-mc.h
index 5e73eb8..246eed3 100644 (file)
--- a/include/media/v4l2-mc.h
+++ b/include/media/v4l2-mc.h
@@ -12,6 +12,7 @@
 
 #include <media/media-device.h>
 #include <media/v4l2-dev.h>
+#include <media/v4l2-subdev.h>
 #include <linux/types.h>
 
 /* We don't need to include pci.h or usb.h here */
@@ -84,6 +85,53 @@ void v4l_disable_media_source(struct video_device *vdev);
  */
 int v4l_vb2q_enable_media_source(struct vb2_queue *q);
 
+/**
+ * v4l2_create_fwnode_links_to_pad - Create fwnode-based links from a
+ *                                   source subdev to a sink subdev pad.
+ *
+ * @src_sd - pointer to a source subdev
+ * @sink - pointer to a subdev sink pad
+ *
+ * This function searches for fwnode endpoint connections from a source
+ * subdevice to a single sink pad, and if suitable connections are found,
+ * translates them into media links to that pad. The function can be
+ * called by the sink subdevice, in its v4l2-async notifier subdev bound
+ * callback, to create links from a bound source subdevice.
+ *
+ * .. note::
+ *
+ *    Any sink subdevice that calls this function must implement the
+ *    .get_fwnode_pad media operation in order to verify endpoints passed
+ *    to the sink are owned by the sink.
+ *
+ * Return 0 on success or a negative error code on failure.
+ */
+int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
+                                   struct media_pad *sink);
+
+/**
+ * v4l2_create_fwnode_links - Create fwnode-based links from a source
+ *                            subdev to a sink subdev.
+ *
+ * @src_sd - pointer to a source subdevice
+ * @sink_sd - pointer to a sink subdevice
+ *
+ * This function searches for any and all fwnode endpoint connections
+ * between source and sink subdevices, and translates them into media
+ * links. The function can be called by the sink subdevice, in its
+ * v4l2-async notifier subdev bound callback, to create all links from
+ * a bound source subdevice.
+ *
+ * .. note::
+ *
+ *    Any sink subdevice that calls this function must implement the
+ *    .get_fwnode_pad media operation in order to verify endpoints passed
+ *    to the sink are owned by the sink.
+ *
+ * Return 0 on success or a negative error code on failure.
+ */
+int v4l2_create_fwnode_links(struct v4l2_subdev *src_sd,
+                            struct v4l2_subdev *sink_sd);
 
 /**
  * v4l2_pipeline_pm_get - Increase the use count of a pipeline