media: rcar-vin: parse Gen3 OF and setup media graph

The parsing and registering CSI-2 subdevices with the v4l2 async
framework is a collaborative effort shared between the VIN instances
which are part of the group. When the last VIN in the group is probed it
asks all other VINs to parse its share of OF and record the async
subdevices it finds in the notifier belonging to the last probed VIN.

Once all CSI-2 subdevices in this notifier are bound proceed to register
all VIN video devices of the group and crate media device links between
all CSI-2 and VIN entities according to the SoC specific routing
configuration.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/rcar-vin/rcar-core.c

@@ -27,6 +27,23 @@
 
 #include "rcar-vin.h"
 
+/*
+ * The companion CSI-2 receiver driver (rcar-csi2) is known
+ * and we know it has one source pad (pad 0) and four sink
+ * pads (pad 1-4). So to translate a pad on the remote
+ * CSI-2 receiver to/from the VIN internal channel number simply
+ * subtract/add one from the pad/channel number.
+ */
+#define rvin_group_csi_pad_to_channel(pad) ((pad) - 1)
+#define rvin_group_csi_channel_to_pad(channel) ((channel) + 1)
+
+/*
+ * Not all VINs are created equal, master VINs control the
+ * routing for other VIN's. We can figure out which VIN is
+ * master by looking at a VINs id.
+ */
+#define rvin_group_id_to_master(vin) ((vin) < 4 ? 0 : 4)
+
 /* -----------------------------------------------------------------------------
  * Gen3 CSI2 Group Allocator
  */
@@ -409,6 +426,216 @@ static int rvin_digital_graph_init(struct rvin_dev *vin)
 	return 0;
 }
 
+/* -----------------------------------------------------------------------------
+ * Group async notifier
+ */
+
+static int rvin_group_notify_complete(struct v4l2_async_notifier *notifier)
+{
+	struct rvin_dev *vin = notifier_to_vin(notifier);
+	const struct rvin_group_route *route;
+	unsigned int i;
+	int ret;
+
+	ret = v4l2_device_register_subdev_nodes(&vin->v4l2_dev);
+	if (ret) {
+		vin_err(vin, "Failed to register subdev nodes\n");
+		return ret;
+	}
+
+	/* Register all video nodes for the group. */
+	for (i = 0; i < RCAR_VIN_NUM; i++) {
+		if (vin->group->vin[i]) {
+			ret = rvin_v4l2_register(vin->group->vin[i]);
+			if (ret)
+				return ret;
+		}
+	}
+
+	/* Create all media device links between VINs and CSI-2's. */
+	mutex_lock(&vin->group->lock);
+	for (route = vin->info->routes; route->mask; route++) {
+		struct media_pad *source_pad, *sink_pad;
+		struct media_entity *source, *sink;
+		unsigned int source_idx;
+
+		/* Check that VIN is part of the group. */
+		if (!vin->group->vin[route->vin])
+			continue;
+
+		/* Check that VIN' master is part of the group. */
+		if (!vin->group->vin[rvin_group_id_to_master(route->vin)])
+			continue;
+
+		/* Check that CSI-2 is part of the group. */
+		if (!vin->group->csi[route->csi].subdev)
+			continue;
+
+		source = &vin->group->csi[route->csi].subdev->entity;
+		source_idx = rvin_group_csi_channel_to_pad(route->channel);
+		source_pad = &source->pads[source_idx];
+
+		sink = &vin->group->vin[route->vin]->vdev.entity;
+		sink_pad = &sink->pads[0];
+
+		/* Skip if link already exists. */
+		if (media_entity_find_link(source_pad, sink_pad))
+			continue;
+
+		ret = media_create_pad_link(source, source_idx, sink, 0, 0);
+		if (ret) {
+			vin_err(vin, "Error adding link from %s to %s\n",
+				source->name, sink->name);
+			break;
+		}
+	}
+	mutex_unlock(&vin->group->lock);
+
+	return ret;
+}
+
+static void rvin_group_notify_unbind(struct v4l2_async_notifier *notifier,
+				     struct v4l2_subdev *subdev,
+				     struct v4l2_async_subdev *asd)
+{
+	struct rvin_dev *vin = notifier_to_vin(notifier);
+	unsigned int i;
+
+	for (i = 0; i < RCAR_VIN_NUM; i++)
+		if (vin->group->vin[i])
+			rvin_v4l2_unregister(vin->group->vin[i]);
+
+	mutex_lock(&vin->group->lock);
+
+	for (i = 0; i < RVIN_CSI_MAX; i++) {
+		if (vin->group->csi[i].fwnode != asd->match.fwnode)
+			continue;
+		vin->group->csi[i].subdev = NULL;
+		vin_dbg(vin, "Unbind CSI-2 %s from slot %u\n", subdev->name, i);
+		break;
+	}
+
+	mutex_unlock(&vin->group->lock);
+}
+
+static int rvin_group_notify_bound(struct v4l2_async_notifier *notifier,
+				   struct v4l2_subdev *subdev,
+				   struct v4l2_async_subdev *asd)
+{
+	struct rvin_dev *vin = notifier_to_vin(notifier);
+	unsigned int i;
+
+	mutex_lock(&vin->group->lock);
+
+	for (i = 0; i < RVIN_CSI_MAX; i++) {
+		if (vin->group->csi[i].fwnode != asd->match.fwnode)
+			continue;
+		vin->group->csi[i].subdev = subdev;
+		vin_dbg(vin, "Bound CSI-2 %s to slot %u\n", subdev->name, i);
+		break;
+	}
+
+	mutex_unlock(&vin->group->lock);
+
+	return 0;
+}
+
+static const struct v4l2_async_notifier_operations rvin_group_notify_ops = {
+	.bound = rvin_group_notify_bound,
+	.unbind = rvin_group_notify_unbind,
+	.complete = rvin_group_notify_complete,
+};
+
+static int rvin_mc_parse_of_endpoint(struct device *dev,
+				     struct v4l2_fwnode_endpoint *vep,
+				     struct v4l2_async_subdev *asd)
+{
+	struct rvin_dev *vin = dev_get_drvdata(dev);
+
+	if (vep->base.port != 1 || vep->base.id >= RVIN_CSI_MAX)
+		return -EINVAL;
+
+	if (!of_device_is_available(to_of_node(asd->match.fwnode))) {
+
+		vin_dbg(vin, "OF device %pOF disabled, ignoring\n",
+			to_of_node(asd->match.fwnode));
+		return -ENOTCONN;
+
+	}
+
+	if (vin->group->csi[vep->base.id].fwnode) {
+		vin_dbg(vin, "OF device %pOF already handled\n",
+			to_of_node(asd->match.fwnode));
+		return -ENOTCONN;
+	}
+
+	vin->group->csi[vep->base.id].fwnode = asd->match.fwnode;
+
+	vin_dbg(vin, "Add group OF device %pOF to slot %u\n",
+		to_of_node(asd->match.fwnode), vep->base.id);
+
+	return 0;
+}
+
+static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
+{
+	unsigned int count = 0;
+	unsigned int i;
+	int ret;
+
+	mutex_lock(&vin->group->lock);
+
+	/* If there already is a notifier something has gone wrong, bail out. */
+	if (WARN_ON(vin->group->notifier)) {
+		mutex_unlock(&vin->group->lock);
+		return -EINVAL;
+	}
+
+	/* If not all VIN's are registered don't register the notifier. */
+	for (i = 0; i < RCAR_VIN_NUM; i++)
+		if (vin->group->vin[i])
+			count++;
+
+	if (vin->group->count != count) {
+		mutex_unlock(&vin->group->lock);
+		return 0;
+	}
+
+	/*
+	 * Have all VIN's look for subdevices. Some subdevices will overlap
+	 * but the parser function can handle it, so each subdevice will
+	 * only be registered once with the notifier.
+	 */
+
+	vin->group->notifier = &vin->notifier;
+
+	for (i = 0; i < RCAR_VIN_NUM; i++) {
+		if (!vin->group->vin[i])
+			continue;
+
+		ret = v4l2_async_notifier_parse_fwnode_endpoints_by_port(
+				vin->group->vin[i]->dev, vin->group->notifier,
+				sizeof(struct v4l2_async_subdev), 1,
+				rvin_mc_parse_of_endpoint);
+		if (ret) {
+			mutex_unlock(&vin->group->lock);
+			return ret;
+		}
+	}
+
+	mutex_unlock(&vin->group->lock);
+
+	vin->group->notifier->ops = &rvin_group_notify_ops;
+
+	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
+	if (ret < 0) {
+		vin_err(vin, "Notifier registration failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static int rvin_mc_init(struct rvin_dev *vin)
 {
 	int ret;
@@ -422,7 +649,15 @@ static int rvin_mc_init(struct rvin_dev *vin)
 	if (ret)
 		return ret;
 
-	return rvin_group_get(vin);
+	ret = rvin_group_get(vin);
+	if (ret)
+		return ret;
+
+	ret = rvin_mc_parse_of_graph(vin);
+	if (ret)
+		rvin_group_put(vin);
+
+	return ret;
 }
 
 /* -----------------------------------------------------------------------------
@@ -542,10 +777,15 @@ static int rcar_vin_remove(struct platform_device *pdev)
 	v4l2_async_notifier_unregister(&vin->notifier);
 	v4l2_async_notifier_cleanup(&vin->notifier);
 
-	if (vin->info->use_mc)
+	if (vin->info->use_mc) {
+		mutex_lock(&vin->group->lock);
+		if (vin->group->notifier == &vin->notifier)
+			vin->group->notifier = NULL;
+		mutex_unlock(&vin->group->lock);
 		rvin_group_put(vin);
-	else
+	} else {
 		v4l2_ctrl_handler_free(&vin->ctrl_handler);
+	}
 
 	rvin_dma_unregister(vin);
 

drivers/media/platform/rcar-vin/rcar-vin.h

@@ -223,9 +223,13 @@ struct rvin_dev {
  *
  * @mdev:		media device which represents the group
  *
- * @lock:		protects the count and vin members
+ * @lock:		protects the count, notifier, vin and csi members
  * @count:		number of enabled VIN instances found in DT
+ * @notifier:		pointer to the notifier of a VIN which handles the
+ *			groups async sub-devices.
  * @vin:		VIN instances which are part of the group
+ * @csi:		array of pairs of fwnode and subdev pointers
+ *			to all CSI-2 subdevices.
  */
 struct rvin_group {
 	struct kref refcount;
@@ -234,7 +238,13 @@ struct rvin_group {
 
 	struct mutex lock;
 	unsigned int count;
+	struct v4l2_async_notifier *notifier;
 	struct rvin_dev *vin[RCAR_VIN_NUM];
+
+	struct {
+		struct fwnode_handle *fwnode;
+		struct v4l2_subdev *subdev;
+	} csi[RVIN_CSI_MAX];
 };
 
 int rvin_dma_register(struct rvin_dev *vin, int irq);