[PATCH v9 24/28] rcar-vin: add link notify for Gen3

Niklas Söderlund
2017-12-08T01:09:06Z

Add the ability to process media device link change request. Link
enabling is a bit complicated on Gen3, whether or not it's possible to
enable a link depends on what other links already are enabled. On Gen3
the 8 VINs are split into two subgroup's (VIN0-3 and VIN4-7) and from a
routing perspective these two groups are independent of each other.
Each subgroup's routing is controlled by the subgroup VIN master
instance (VIN0 and VIN4).

There are a limited number of possible route setups available for each
subgroup and the configuration of each setup is dictated by the
hardware. On H3 for example there are 6 possible route setups for each
subgroup to choose from.

This leads to the media device link notification code being rather large
since it will find the best routing configuration to try and accommodate
as many links as possible. When it's not possible to enable a new link
due to hardware constrains the link_notifier callback will return
-EMLINK.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
---
drivers/media/platform/rcar-vin/rcar-core.c | 205 ++++++++++++++++++++++++++++
1 file changed, 205 insertions(+)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 4a147437fa69c364..09ebeff1580556dc 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -27,6 +27,209 @@

#include "rcar-vin.h"

+/* -----------------------------------------------------------------------------
+ * Media Controller link notification
+ */
+
+static unsigned int rvin_group_csi_pad_to_chan(unsigned int pad)
+{
+ /*
+ * The companion CSI-2 receiver driver (rcar-csi2) is known
+ * and we know it have one source pad (pad 0) and four sink
+ * pads (pad 1-4). So to translate a pad on the remote
+ * CSI-2 receiver to the VIN internal channel number simply
+ * subtract one from the pad number.
+ */
+ return pad - 1;
+}
+
+/* group lock should be held when calling this function */
+static int rvin_group_entity_to_vin_num(struct rvin_group *group,
+ struct media_entity *entity)
+{
+ struct video_device *vdev;
+ int i;
+
+ if (!is_media_entity_v4l2_video_device(entity))
+ return -ENODEV;
+
+ vdev = media_entity_to_video_device(entity);
+
+ for (i = 0; i < RCAR_VIN_NUM; i++) {
+ if (!group->vin[i])
+ continue;
+
+ if (&group->vin[i]->vdev == vdev)
+ return i;
+ }
+
+ return -ENODEV;
+}
+
+/* group lock should be held when calling this function */
+static int rvin_group_entity_to_csi_num(struct rvin_group *group,
+ struct media_entity *entity)
+{
+ struct v4l2_subdev *sd;
+ int i;
+
+ if (!is_media_entity_v4l2_subdev(entity))
+ return -ENODEV;
+
+ sd = media_entity_to_v4l2_subdev(entity);
+
+ for (i = 0; i < RVIN_CSI_MAX; i++)
+ if (group->csi[i].subdev == sd)
+ return i;
+
+ return -ENODEV;
+}
+
+/* group lock should be held when calling this function */
+static void __rvin_group_build_link_list(struct rvin_group *group,
+ struct rvin_group_chsel *map,
+ int start, int len)
+{
+ struct media_pad *vin_pad, *remote_pad;
+ unsigned int n;
+
+ for (n = 0; n < len; n++) {
+ map[n].csi = -1;
+ map[n].chan = -1;
+
+ if (!group->vin[start + n])
+ continue;
+
+ vin_pad = &group->vin[start + n]->vdev.entity.pads[0];
+
+ remote_pad = media_entity_remote_pad(vin_pad);
+ if (!remote_pad)
+ continue;
+
+ map[n].csi =
+ rvin_group_entity_to_csi_num(group, remote_pad->entity);
+ map[n].chan = rvin_group_csi_pad_to_chan(remote_pad->index);
+ }
+}
+
+/* group lock should be held when calling this function */
+static int __rvin_group_try_get_chsel(struct rvin_group *group,
+ struct rvin_group_chsel *map,
+ int start, int len)
+{
+ const struct rvin_group_chsel *sel;
+ unsigned int i, n;
+ int chsel;
+
+ for (i = 0; i < group->vin[start]->info->num_chsels; i++) {
+ chsel = i;
+ for (n = 0; n < len; n++) {
+
+ /* If the link is not active it's OK */
+ if (map[n].csi == -1)
+ continue;
+
+ /* Check if chsel matches requested link */
+ sel = &group->vin[start]->info->chsels[start + n][i];
+ if (map[n].csi != sel->csi ||
+ map[n].chan != sel->chan) {
+ chsel = -1;
+ break;
+ }
+ }
+
+ /* A chsel which satisfies the links has been found */
+ if (chsel != -1)
+ return chsel;
+ }
+
+ /* No chsel can satisfy the requested links */
+ return -1;
+}
+
+/* group lock should be held when calling this function */
+static bool rvin_group_in_use(struct rvin_group *group)
+{
+ struct media_entity *entity;
+
+ media_device_for_each_entity(entity, &group->mdev)
+ if (entity->use_count)
+ return true;
+
+ return false;
+}
+
+static int rvin_group_link_notify(struct media_link *link, u32 flags,
+ unsigned int notification)
+{
+ struct rvin_group *group = container_of(link->graph_obj.mdev,
+ struct rvin_group, mdev);
+ struct rvin_group_chsel chsel_map[4];
+ int vin_num, vin_master, csi_num, csi_chan;
+ unsigned int chsel;
+
+ mutex_lock(&group->lock);
+
+ vin_num = rvin_group_entity_to_vin_num(group, link->sink->entity);
+ csi_num = rvin_group_entity_to_csi_num(group, link->source->entity);
+ csi_chan = rvin_group_csi_pad_to_chan(link->source->index);
+
+ /*
+ * Figure out which VIN node is the subgroup master.
+ *
+ * VIN0-3 are controlled by VIN0
+ * VIN4-7 are controlled by VIN4
+ */
+ vin_master = vin_num < 4 ? 0 : 4;
+
+ /* If not all devices exist something is horribly wrong */
+ if (vin_num < 0 || csi_num < 0 || !group->vin[vin_master])
+ goto error;
+
+ /* Special checking only needed for links which are to be enabled */
+ if (notification != MEDIA_DEV_NOTIFY_PRE_LINK_CH ||
+ !(flags & MEDIA_LNK_FL_ENABLED))
+ goto out;
+
+ /* If any link in the group is in use, no new link can be enabled */
+ if (rvin_group_in_use(group))
+ goto error;
+
+ /* If the VIN already has an active link it's busy */
+ if (media_entity_remote_pad(&link->sink->entity->pads[0]))
+ goto error;
+
+ /* Build list of active links */
+ __rvin_group_build_link_list(group, chsel_map, vin_master, 4);
+
+ /* Add the new proposed link */
+ chsel_map[vin_num - vin_master].csi = csi_num;
+ chsel_map[vin_num - vin_master].chan = csi_chan;
+
+ /* See if there is a chsel value which matches our link selection */
+ chsel = __rvin_group_try_get_chsel(group, chsel_map, vin_master, 4);
+
+ /* No chsel can provide the requested links */
+ if (chsel == -1)
+ goto error;
+
+ /* Update chsel value at group master */
+ rvin_set_chsel(group->vin[vin_master], chsel);
+
+out:
+ mutex_unlock(&group->lock);
+
+ return v4l2_pipeline_link_notify(link, flags, notification);
+error:
+ mutex_unlock(&group->lock);
+
+ return -EMLINK;
+}
+
+static const struct media_device_ops rvin_media_ops = {
+ .link_notify = rvin_group_link_notify,
+};
+
/* -----------------------------------------------------------------------------
* Gen3 CSI2 Group Allocator
*/
@@ -147,6 +350,8 @@ static int rvin_group_allocate(struct rvin_dev *vin)
dev_name(mdev->dev));
media_device_init(mdev);

+ mdev->ops = &rvin_media_ops;
+
ret = media_device_register(mdev);
if (ret) {
vin_err(vin, "Failed to register media device\n");
--
2.15.0