Re: [PATCH v6 22/25] rcar-vin: add link notify for Gen3

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On 23/08/17 01:26, Niklas Söderlund wrote:
> Add the ability to process media device link change request. Link
> enablement are a bit complicated on Gen3, if it's possible to enable a

enablement are -> enabling is

if -> whether or not

> link depends on what other links already are enabled. On Gen3 the 8 VIN

VIN -> VINs

> are split into two subgroups (VIN0-3 and VIN4-7) and from a routing
> perspective these two groups are independent of each other. Each
> subgroups routing is controlled by the subgroup VIN master instance

subgroups -> subgroup's

> (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@xxxxxxxxxxxx>

See various comments below.

> ---
>  drivers/media/platform/rcar-vin/rcar-core.c | 203 ++++++++++++++++++++++++++++
>  1 file changed, 203 insertions(+)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
> index 2aba442a0750e91a..dec91e2f3ccdbd93 100644
> --- a/drivers/media/platform/rcar-vin/rcar-core.c
> +++ b/drivers/media/platform/rcar-vin/rcar-core.c
> @@ -26,6 +26,207 @@
>  
>  #include "rcar-vin.h"
>  
> +/* -----------------------------------------------------------------------------
> + * Media Controller link notification
> + */
> +
> +static unsigned int rvin_group_csi_pad_to_chan(unsigned int pad)
> +{
> +	/*
> +	 * The CSI2 driver is rcar-csi2 and we know it's pad layout are

it's -> its

> +	 * 0: Source 1-4: Sinks so if we remove one from the pad we

I don't follow. '0: Source 1-4: Sinks' is too cryptic for me.

> +	 * get the rcar-vin internal CSI2 channel 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 match requested link */

match -> matches

> +			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 satisfy the links have been found */

satisfy -> satifies
have -> has

> +		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 exists something is horribly wrong */

exists -> exist

> +	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 are in use, no new link can be enabled */

are -> is

> +	if (rvin_group_in_use(group))
> +		goto error;
> +
> +	/* If the VIN already have a active link it's busy */

have -> has
a -> an

> +	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 match our link selection */

match -> matches

> +	chsel = __rvin_group_try_get_chsel(group, chsel_map, vin_master, 4);
> +
> +	/* No chsel can provide the request links */

request -> requested

> +	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
>   */
> @@ -146,6 +347,8 @@ static int rvin_group_allocate(struct rvin_dev *vin)
>  			sizeof(mdev->bus_info));
>  		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");
> 

Regards,

	Hans



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