From 06564411dcd10277eb5e192106603114cac3fd3f Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 19 Jun 2024 02:42:34 +0300 Subject: [PATCH 1/6] media: microchip-isc: Drop v4l2_subdev_link_validate() for video devices The v4l2_subdev_link_validate() function is a helper designed to validate links whose sink is a subdev. When called on a link whose sink is a video device, it only prints a warning and returns. As the microchip-isc driver implements manual validate of the subdev to video device link, we can just drop the v4l2_subdev_link_validate() to avoid the warning. Signed-off-by: Laurent Pinchart Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- .../platform/microchip/microchip-isc-base.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c index f3a5cbacadbe09..28e56f6a695da2 100644 --- a/drivers/media/platform/microchip/microchip-isc-base.c +++ b/drivers/media/platform/microchip/microchip-isc-base.c @@ -902,8 +902,11 @@ static int isc_set_fmt(struct isc_device *isc, struct v4l2_format *f) return 0; } -static int isc_validate(struct isc_device *isc) +static int isc_link_validate(struct media_link *link) { + struct video_device *vdev = + media_entity_to_video_device(link->sink->entity); + struct isc_device *isc = video_get_drvdata(vdev); int ret; int i; struct isc_format *sd_fmt = NULL; @@ -1906,20 +1909,6 @@ int microchip_isc_pipeline_init(struct isc_device *isc) } EXPORT_SYMBOL_GPL(microchip_isc_pipeline_init); -static int isc_link_validate(struct media_link *link) -{ - struct video_device *vdev = - media_entity_to_video_device(link->sink->entity); - struct isc_device *isc = video_get_drvdata(vdev); - int ret; - - ret = v4l2_subdev_link_validate(link); - if (ret) - return ret; - - return isc_validate(isc); -} - static const struct media_entity_operations isc_entity_operations = { .link_validate = isc_link_validate, }; From 2dc5d5d401f5c6cecd97800ffef82e8d17d228f0 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 19 Jun 2024 02:46:16 +0300 Subject: [PATCH 2/6] media: sun4i_csi: Implement link validate for sun4i_csi subdev The sun4i_csi driver doesn't implement link validation for the subdev it registers, leaving the link between the subdev and its source unvalidated. Fix it, using the v4l2_subdev_link_validate() helper. Fixes: 577bbf23b758 ("media: sunxi: Add A10 CSI driver") Cc: stable@vger.kernel.org Signed-off-by: Laurent Pinchart Acked-by: Chen-Yu Tsai Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c index 097a3a08ef7d1f..dbb26c7b2f8d7a 100644 --- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c @@ -39,6 +39,10 @@ static const struct media_entity_operations sun4i_csi_video_entity_ops = { .link_validate = v4l2_subdev_link_validate, }; +static const struct media_entity_operations sun4i_csi_subdev_entity_ops = { + .link_validate = v4l2_subdev_link_validate, +}; + static int sun4i_csi_notify_bound(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_connection *asd) @@ -214,6 +218,7 @@ static int sun4i_csi_probe(struct platform_device *pdev) subdev->internal_ops = &sun4i_csi_subdev_internal_ops; subdev->flags = V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS; subdev->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE; + subdev->entity.ops = &sun4i_csi_subdev_entity_ops; subdev->owner = THIS_MODULE; snprintf(subdev->name, sizeof(subdev->name), "sun4i-csi-0"); v4l2_set_subdevdata(subdev, csi); From 9bde4f7caf38df94257d2483e89f371b1a530e9a Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 19 Jun 2024 02:46:16 +0300 Subject: [PATCH 3/6] media: sun4i_csi: Don't use v4l2_subdev_link_validate() for video device The v4l2_subdev_link_validate() function is a helper designed to validate links whose sink is a subdev. When called on a link whose sink is a video device, it only prints a warning and returns. Its usage in the sun4i_csi driver is wrong, leaving the link from the sub4i_csi subdev to the capture video device unvalidated. Planned improvements to the v4l2_subdev_link_validate() function will turn the warning into an error, breaking the sun4i_csi driver. As an interim measure, move the warning to the sun4i_csi driver in a custom validation handler, and drop the call to the helper. Signed-off-by: Laurent Pinchart Acked-by: Chen-Yu Tsai Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c index dbb26c7b2f8d7a..d07e980aba61c8 100644 --- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c @@ -35,8 +35,15 @@ struct sun4i_csi_traits { bool has_isp; }; +static int sun4i_csi_video_link_validate(struct media_link *link) +{ + dev_warn_once(link->graph_obj.mdev->dev, + "Driver bug: link validation not implemented\n"); + return 0; +} + static const struct media_entity_operations sun4i_csi_video_entity_ops = { - .link_validate = v4l2_subdev_link_validate, + .link_validate = sun4i_csi_video_link_validate, }; static const struct media_entity_operations sun4i_csi_subdev_entity_ops = { From d1307671e5221967809c4b626affbad29e371006 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 19 Jun 2024 02:56:01 +0300 Subject: [PATCH 4/6] media: v4l2-subdev: Refactor warnings in v4l2_subdev_link_validate() The v4l2_subdev_link_validate() function prints a one-time warning if it gets called on a link whose source or sink is not a subdev. As links get validated in the context of their sink, a call to the helper when the link's sink is not a subdev indicates that the driver has set its .link_validate() handler to v4l2_subdev_link_validate() on a non-subdev entity, which is a clear driver bug. On the other hand, the link's source not being a subdev indicates that the helper is used for a subdev connected to a video output device, which is a lesser issue, if only because this is currently common practice. There are no drivers left in the kernel that use v4l2_subdev_link_validate() in a context where it may get called on a non-subdev sink. Replace the pr_warn_once() with a WARN_ON_ONCE() in this case to make sure that new offenders won't be introduced. A subsequent change will improve the v4l2_subdev_link_validate() helper to properly support validating video device to subdev links. Signed-off-by: Laurent Pinchart Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- drivers/media/v4l2-core/v4l2-subdev.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 7c5812d5531512..d3196042d5c571 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -1443,11 +1443,15 @@ int v4l2_subdev_link_validate(struct media_link *link) bool states_locked; int ret; - if (!is_media_entity_v4l2_subdev(link->sink->entity) || - !is_media_entity_v4l2_subdev(link->source->entity)) { - pr_warn_once("%s of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\n", - !is_media_entity_v4l2_subdev(link->sink->entity) ? - "sink" : "source", + /* + * Links are validated in the context of the sink entity. Usage of this + * helper on a sink that is not a subdev is a clear driver bug. + */ + if (WARN_ON_ONCE(!is_media_entity_v4l2_subdev(link->sink->entity))) + return -EINVAL; + + if (!is_media_entity_v4l2_subdev(link->source->entity)) { + pr_warn_once("source of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\n", link->source->entity->name, link->source->index, link->sink->entity->name, link->sink->index); return 0; From 5fd3e2412ade67ea20d855f0aea821c650d27559 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 19 Jun 2024 03:02:42 +0300 Subject: [PATCH 5/6] media: v4l2-subdev: Support hybrid links in v4l2_subdev_link_validate() The v4l2_subdev_link_validate() helper function is meant to be used as a drop-in implementation of a V4L2 subdev entity .link_validate() handler. It supports subdev-to-subdev links only, and complains if one end of the link is not a subdev. This forces drivers that have video output devices connected to subdevs to implement a custom .link_validate() handler, calling v4l2_subdev_link_validate() for the subdev-to-subdev links, and performing manual link validation for the video-to-subdev links. Video devices embed a media entity, and therefore also have a .link_validate() operation. For video capture devices, the operation should be manually implemented by drivers for validate the subdev-to-video links. For video output devices, on the other hand, that operation is never called, as link validation is performed in the context of the sink entity. As a result, we end up forcing drivers to implement a custom .link_validate() handler for subdevs connected to video output devices, when the video devices provide an operation that could be used for that purpose. To improve that situation, make v4l2_subdev_link_validate() delegate link validation to the source's .link_validate() operation when the link source is a video device and the link sink is a subdev. This allows broader usage of v4l2_subdev_link_validate(), and simplifies drivers by making video device link validation easy to implement in the video device .link_validate(), regardless of whether the video device is an output device or a capture device. Signed-off-by: Laurent Pinchart Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- drivers/media/v4l2-core/v4l2-subdev.c | 43 +++++++++++++++++++++++---- include/media/v4l2-subdev.h | 6 ++++ 2 files changed, 44 insertions(+), 5 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index d3196042d5c571..3a4ba08810d249 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -1450,13 +1450,46 @@ int v4l2_subdev_link_validate(struct media_link *link) if (WARN_ON_ONCE(!is_media_entity_v4l2_subdev(link->sink->entity))) return -EINVAL; - if (!is_media_entity_v4l2_subdev(link->source->entity)) { - pr_warn_once("source of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\n", - link->source->entity->name, link->source->index, - link->sink->entity->name, link->sink->index); - return 0; + /* + * If the source is a video device, delegate link validation to it. This + * allows usage of this helper for subdev connected to a video output + * device, provided that the driver implement the video output device's + * .link_validate() operation. + */ + if (is_media_entity_v4l2_video_device(link->source->entity)) { + struct media_entity *source = link->source->entity; + + if (!source->ops || !source->ops->link_validate) { + /* + * Many existing drivers do not implement the required + * .link_validate() operation for their video devices. + * Print a warning to get the drivers fixed, and return + * 0 to avoid breaking userspace. This should + * eventually be turned into a WARN_ON() when all + * drivers will have been fixed. + */ + pr_warn_once("video device '%s' does not implement .link_validate(), driver bug!\n", + source->name); + return 0; + } + + /* + * Avoid infinite loops in case a video device incorrectly uses + * this helper function as its .link_validate() handler. + */ + if (WARN_ON(source->ops->link_validate == v4l2_subdev_link_validate)) + return -EINVAL; + + return source->ops->link_validate(link); } + /* + * If the source is still not a subdev, usage of this helper is a clear + * driver bug. + */ + if (WARN_ON(!is_media_entity_v4l2_subdev(link->source->entity))) + return -EINVAL; + sink_sd = media_entity_to_v4l2_subdev(link->sink->entity); source_sd = media_entity_to_v4l2_subdev(link->source->entity); diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index bd235d325ff96c..8daa0929865cfa 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -1250,6 +1250,12 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd, * calls v4l2_subdev_link_validate_default() to ensure that * width, height and the media bus pixel code are equal on both * source and sink of the link. + * + * The function can be used as a drop-in &media_entity_ops.link_validate + * implementation for v4l2_subdev instances. It supports all links between + * subdevs, as well as links between subdevs and video devices, provided that + * the video devices also implement their &media_entity_ops.link_validate + * operation. */ int v4l2_subdev_link_validate(struct media_link *link); From a3d44f011c6b7a87c9ad0d5be2f5fa092fa419bf Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Tue, 18 Jun 2024 21:46:44 +0300 Subject: [PATCH 6/6] media: renesas: vsp1: Implement .link_validate() for video devices The v4l2_subdev_link_validate() helper prints a warning if the .link_validate() operation is not implemented for video devices connected to the subdevs. Implement the operation to silence the warning. Ideally validation of the link between the video device and the subdev should be implemented in that operation. That would however break userspace that does not configure formats on all video devices before starting streaming. While this mode of operation may not be considered valid by the V4L2 API specification (interpretation differ), it is nonetheless supported by the vsp1 driver at the moment and used by at least the vsp1 unit test suite, and possibly other userspace applications. Removing it would be a regression. Signed-off-by: Laurent Pinchart Reviewed-by: Tomi Valkeinen Acked-by: Sakari Ailus --- .../media/platform/renesas/vsp1/vsp1_video.c | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/media/platform/renesas/vsp1/vsp1_video.c b/drivers/media/platform/renesas/vsp1/vsp1_video.c index fdb46ec0c872a1..e728f9f5160e42 100644 --- a/drivers/media/platform/renesas/vsp1/vsp1_video.c +++ b/drivers/media/platform/renesas/vsp1/vsp1_video.c @@ -1081,6 +1081,27 @@ static const struct v4l2_file_operations vsp1_video_fops = { .mmap = vb2_fop_mmap, }; +/* ----------------------------------------------------------------------------- + * Media entity operations + */ + +static int vsp1_video_link_validate(struct media_link *link) +{ + /* + * Ideally, link validation should be implemented here instead of + * calling vsp1_video_verify_format() in vsp1_video_streamon() + * manually. That would however break userspace that start one video + * device before configures formats on other video devices in the + * pipeline. This operation is just a no-op to silence the warnings + * from v4l2_subdev_link_validate(). + */ + return 0; +} + +static const struct media_entity_operations vsp1_video_media_ops = { + .link_validate = vsp1_video_link_validate, +}; + /* ----------------------------------------------------------------------------- * Suspend and Resume */ @@ -1215,6 +1236,7 @@ struct vsp1_video *vsp1_video_create(struct vsp1_device *vsp1, /* ... and the video node... */ video->video.v4l2_dev = &video->vsp1->v4l2_dev; + video->video.entity.ops = &vsp1_video_media_ops; video->video.fops = &vsp1_video_fops; snprintf(video->video.name, sizeof(video->video.name), "%s %s", rwpf->entity.subdev.name, direction);