Hi Jacopo and Laurent,
Thanks for your feedback!
On 2021-11-10 19:48:05 +0200, Laurent Pinchart wrote:
> On Thu, Nov 04, 2021 at 05:36:54PM +0100, Jacopo Mondi wrote:
> > On Wed, Oct 20, 2021 at 10:02:23PM +0200, Niklas Söderlund wrote:
> > > The code have grown organically and a lot of checks are preformed for
> >
> > code -> has
> > preformed -> performed
> >
> > > the CSI-2 use-case even if the link notify is for a subdevice connected
> > > to the parallel interface.
> > >
> > > Before reworking the CSI-2 routing logic split the CSI-2 and parallel
> > > link notify code in two separate blocks to make it clearer. There is no
> > > functional change.
> > >
> > > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > > ---
> > > drivers/media/platform/rcar-vin/rcar-core.c | 87 +++++++++++----------
> > > 1 file changed, 45 insertions(+), 42 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
> > > index 1d92cc8ede8f8a3e..bd960c348ba5228c 100644
> > > --- a/drivers/media/platform/rcar-vin/rcar-core.c
> > > +++ b/drivers/media/platform/rcar-vin/rcar-core.c
> > > @@ -795,12 +795,10 @@ static int rvin_csi2_link_notify(struct media_link *link, u32 flags,
> > > {
> > > struct rvin_group *group = container_of(link->graph_obj.mdev,
> > > struct rvin_group, mdev);
> > > - unsigned int master_id, channel, mask_new, i;
> > > - unsigned int mask = ~0;
> > > struct media_entity *entity;
> > > struct video_device *vdev;
> > > - struct media_pad *csi_pad;
> > > - struct rvin_dev *vin = NULL;
> > > + struct rvin_dev *vin;
> > > + unsigned int i;
> > > int csi_id, ret;
> > >
> > > ret = v4l2_pipeline_link_notify(link, flags, notification);
> > > @@ -826,33 +824,9 @@ static int rvin_csi2_link_notify(struct media_link *link, u32 flags,
> > > /* Find the master VIN that controls the routes. */
> > > vdev = media_entity_to_video_device(link->sink->entity);
> > > vin = container_of(vdev, struct rvin_dev, vdev);
> > > - master_id = rvin_group_id_to_master(vin->id);
> > >
> > > - if (WARN_ON(!group->vin[master_id])) {
> > > - ret = -ENODEV;
> > > - goto out;
> > > - }
> > >
> > > - /* Build a mask for already enabled links. */
> > > - for (i = master_id; i < master_id + 4; i++) {
> > > - if (!group->vin[i])
> > > - continue;
> > > -
> > > - /* Get remote CSI-2, if any. */
> > > - csi_pad = media_entity_remote_pad(
> > > - &group->vin[i]->vdev.entity.pads[0]);
> > > - if (!csi_pad)
> > > - continue;
> > > -
> > > - csi_id = rvin_group_entity_to_remote_id(group, csi_pad->entity);
> > > - channel = rvin_group_csi_pad_to_channel(csi_pad->index);
> > > -
> > > - mask &= rvin_csi2_get_mask(group->vin[i], csi_id, channel);
> > > - }
> > > -
> >
> > There are now two empty lines here
> >
> > > - /* Add the new link to the existing mask and check if it works. */
> > > csi_id = rvin_group_entity_to_remote_id(group, link->source->entity);
> > > -
> > > if (csi_id == -ENODEV) {
> > > struct v4l2_subdev *sd;
> > >
> > > @@ -877,25 +851,54 @@ static int rvin_csi2_link_notify(struct media_link *link, u32 flags,
> > > vin_err(vin, "Subdevice %s not registered to any VIN\n",
> > > link->source->entity->name);
> > > ret = -ENODEV;
> > > - goto out;
> > > - }
> > > + } else {
> >
> > I wonder if the group mutex should be locked in the else branch only
> > and simplify the whole thing as:
>
> Isn't the lock required to call rvin_group_entity_to_remote_id() ? I
> think the two lines before:
>
> vdev = media_entity_to_video_device(link->sink->entity);
> vin = container_of(vdev, struct rvin_dev, vdev);
>
> could however be moved before mutex_lock().
>
> > if (csi_id == -ENODEV) {
> > /* subdev is parallel. */
> > for () {
>
> Unless I'm mistaken, this needs locking in order to access group->vin[]
> safely.
As Laurent points out it is needed to hold the lock both to call
rvin_group_entity_to_remote_id() and to access group->vin[i].
I have taken the suggestion to move the lookup of vdev and vin outside
the mutex.
>
> > return 0;
> > }
> >
> > return -ENODEV;
> > }
> >
> > /* subdev is CSI-2 */
> > mutex_lock(group->mutex);
> >
> > ...
> >
> > mutex_unlock(group->mutex);
> >
> > Even if I see above:
> >
> > /*
> > * Don't allow link changes if any stream in the graph is active as
> > * modifying the CHSEL register fields can disrupt running streams.
> > */
> > media_device_for_each_entity(entity, &group->mdev) {
> > struct media_pad *iter;
> >
> > media_entity_for_each_pad(entity, iter) {
> > if (iter->stream_count)
> > return -EBUSY;
> > }
> > }
> >
> > Being run out of the critical session, but that was already the case.
> >
> >
> >
> > > + unsigned int master_id, channel, mask_new;
> > > + unsigned int mask = ~0;
> > > + struct media_pad *csi_pad;
> > >
> > > - channel = rvin_group_csi_pad_to_channel(link->source->index);
> > > - mask_new = mask & rvin_csi2_get_mask(vin, csi_id, channel);
> > > - vin_dbg(vin, "Try link change mask: 0x%x new: 0x%x\n", mask, mask_new);
> > > + master_id = rvin_group_id_to_master(vin->id);
> > >
> > > - if (!mask_new) {
> > > - ret = -EMLINK;
> > > - goto out;
> > > - }
> > > + if (WARN_ON(!group->vin[master_id])) {
> > > + ret = -ENODEV;
> > > + goto out;
> > > + }
> > > +
> > > + /* Build a mask for already enabled links. */
> > > + for (i = master_id; i < master_id + 4; i++) {
> > > + if (!group->vin[i])
> > > + continue;
> > > +
> > > + /* Get remote CSI-2, if any. */
> > > + csi_pad = media_entity_remote_pad(
> > > + &group->vin[i]->vdev.entity.pads[0]);
> > > + if (!csi_pad)
> > > + continue;
> > >
> > > - /* New valid CHSEL found, set the new value. */
> > > - ret = rvin_set_channel_routing(group->vin[master_id], __ffs(mask_new));
> > > - if (ret)
> > > - goto out;
> > > + csi_id = rvin_group_entity_to_remote_id(group,
> > > + csi_pad->entity);
> > > + channel = rvin_group_csi_pad_to_channel(csi_pad->index);
> > >
> > > - vin->is_csi = true;
> > > + mask &= rvin_csi2_get_mask(group->vin[i], csi_id, channel);
> > > + }
> > >
> > > + channel = rvin_group_csi_pad_to_channel(link->source->index);
> > > + mask_new = mask & rvin_csi2_get_mask(vin, csi_id, channel);
> > > + vin_dbg(vin, "Try link change mask: 0x%x new: 0x%x\n", mask,
> > > + mask_new);
> > > +
> > > + if (!mask_new) {
> > > + ret = -EMLINK;
> > > + goto out;
> > > + }
> > > +
> > > + /* New valid CHSEL found, set the new value. */
> > > + ret = rvin_set_channel_routing(group->vin[master_id],
> > > + __ffs(mask_new));
> > > + if (ret)
> > > + goto out;
> > > +
> > > + vin->is_csi = true;
>
> I'm tempted to factor code out to two functions for the parallel and
> CSI-2 case, but it could be done later too.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> > > + }
> > > out:
> > > mutex_unlock(&group->lock);
> > >
>
> --
> Regards,
>
> Laurent Pinchart
--
Kind Regards,
Niklas Söderlund
