Re: [PATCH v6 6/6] media: sun6i-csi: Add support for hooking to the isp devices

Laurent Pinchart
2022-08-26T22:44:16Z

Hi Paul,

Thank you for the patch.

On Fri, Aug 26, 2022 at 08:41:44PM +0200, Paul Kocialkowski wrote:
> In order to use the isp and csi together, both devices need to be
> parented to the same v4l2 and media devices. We use the isp as
> top-level device and let the csi code hook to its v4l2 and media
> devices when async subdev registration takes place.

Have you considered the option of making the CSI the master device, with
the ISP registering an async subdev instead ?

I'm also wondering, what will happen if userspace tries to capture from
both the CSI output and the ISP output at the same time ?

> As a result v4l2/media device setup is only called when the ISP
> is missing and the capture device is registered after the devices
> are hooked. The bridge subdev and its notifier are registered
> without any device when the ISP is available. Top-level pointers
> for the devices are introduced to either redirect to the hooked ones
> (isp available) or the registered ones (isp missing).
>
> Also keep track of whether the capture node was setup or not to
> avoid cleaning up resources when it wasn't.
>
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> ---
> .../platform/sunxi/sun6i-csi/sun6i_csi.c | 45 +++++++++++++++----
> .../platform/sunxi/sun6i-csi/sun6i_csi.h | 7 +++
> .../sunxi/sun6i-csi/sun6i_csi_bridge.c | 32 +++++++++++--
> .../sunxi/sun6i-csi/sun6i_csi_capture.c | 19 ++++++--
> .../sunxi/sun6i-csi/sun6i_csi_capture.h | 1 +
> 5 files changed, 89 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> index b16166cba2ef..0bac89d8112f 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> @@ -26,6 +26,18 @@
>
> /* ISP */
>
> +int sun6i_csi_isp_complete(struct sun6i_csi_device *csi_dev,
> + struct v4l2_device *v4l2_dev)
> +{
> + if (csi_dev->v4l2_dev && csi_dev->v4l2_dev != v4l2_dev)
> + return -EINVAL;
> +
> + csi_dev->v4l2_dev = v4l2_dev;
> + csi_dev->media_dev = v4l2_dev->mdev;
> +
> + return sun6i_csi_capture_setup(csi_dev);
> +}
> +
> static bool sun6i_csi_isp_detect(struct sun6i_csi_device *csi_dev)
> {
> struct device *dev = csi_dev->dev;
> @@ -95,6 +107,9 @@ static int sun6i_csi_v4l2_setup(struct sun6i_csi_device *csi_dev)
> goto error_media;
> }
>
> + csi_dev->v4l2_dev = v4l2_dev;
> + csi_dev->media_dev = media_dev;
> +
> return 0;
>
> error_media:
> @@ -323,17 +338,27 @@ static int sun6i_csi_probe(struct platform_device *platform_dev)
> if (ret)
> goto error_resources;
>
> - ret = sun6i_csi_v4l2_setup(csi_dev);
> - if (ret)
> - goto error_resources;
> + /*
> + * Register our own v4l2 and media devices when there is no ISP around.
> + * Otherwise the ISP will use async subdev registration with our bridge,
> + * which will provide v4l2 and media devices that are used to register
> + * the video interface.
> + */
> + if (!csi_dev->isp_available) {
> + ret = sun6i_csi_v4l2_setup(csi_dev);
> + if (ret)
> + goto error_resources;
> + }
>
> ret = sun6i_csi_bridge_setup(csi_dev);
> if (ret)
> goto error_v4l2;
>
> - ret = sun6i_csi_capture_setup(csi_dev);
> - if (ret)
> - goto error_bridge;
> + if (!csi_dev->isp_available) {
> + ret = sun6i_csi_capture_setup(csi_dev);
> + if (ret)
> + goto error_bridge;
> + }
>
> return 0;
>
> @@ -341,7 +366,8 @@ static int sun6i_csi_probe(struct platform_device *platform_dev)
> sun6i_csi_bridge_cleanup(csi_dev);
>
> error_v4l2:
> - sun6i_csi_v4l2_cleanup(csi_dev);
> + if (!csi_dev->isp_available)
> + sun6i_csi_v4l2_cleanup(csi_dev);
>
> error_resources:
> sun6i_csi_resources_cleanup(csi_dev);
> @@ -355,7 +381,10 @@ static int sun6i_csi_remove(struct platform_device *pdev)
>
> sun6i_csi_capture_cleanup(csi_dev);
> sun6i_csi_bridge_cleanup(csi_dev);
> - sun6i_csi_v4l2_cleanup(csi_dev);
> +
> + if (!csi_dev->isp_available)
> + sun6i_csi_v4l2_cleanup(csi_dev);
> +
> sun6i_csi_resources_cleanup(csi_dev);
>
> return 0;
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h
> index 8e232cd91ebe..bc3f0dae35df 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.h
> @@ -36,6 +36,8 @@ struct sun6i_csi_v4l2 {
>
> struct sun6i_csi_device {
> struct device *dev;
> + struct v4l2_device *v4l2_dev;
> + struct media_device *media_dev;
>
> struct sun6i_csi_v4l2 v4l2;
> struct sun6i_csi_bridge bridge;
> @@ -53,4 +55,9 @@ struct sun6i_csi_variant {
> unsigned long clock_mod_rate;
> };
>
> +/* ISP */
> +
> +int sun6i_csi_isp_complete(struct sun6i_csi_device *csi_dev,
> + struct v4l2_device *v4l2_dev);
> +
> #endif
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_bridge.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_bridge.c
> index 492f93b0db28..86d20c1c35ed 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_bridge.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_bridge.c
> @@ -653,6 +653,7 @@ sun6i_csi_bridge_notifier_bound(struct v4l2_async_notifier *notifier,
> struct sun6i_csi_bridge *bridge = &csi_dev->bridge;
> struct sun6i_csi_bridge_source *source = bridge_async_subdev->source;
> bool enabled;
> + int ret;
>
> switch (source->endpoint.base.port) {
> case SUN6I_CSI_PORT_PARALLEL:
> @@ -667,6 +668,16 @@ sun6i_csi_bridge_notifier_bound(struct v4l2_async_notifier *notifier,
>
> source->subdev = remote_subdev;
>
> + if (csi_dev->isp_available) {
> + /*
> + * Hook to the first available remote subdev to get v4l2 and
> + * media devices and register the capture device then.
> + */
> + ret = sun6i_csi_isp_complete(csi_dev, remote_subdev->v4l2_dev);
> + if (ret)
> + return ret;
> + }
> +
> return sun6i_csi_bridge_link(csi_dev, SUN6I_CSI_BRIDGE_PAD_SINK,
> remote_subdev, enabled);
> }
> @@ -679,6 +690,9 @@ sun6i_csi_bridge_notifier_complete(struct v4l2_async_notifier *notifier)
> bridge.notifier);
> struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;
>
> + if (csi_dev->isp_available)
> + return 0;
> +
> return v4l2_device_register_subdev_nodes(v4l2_dev);
> }
>
> @@ -752,7 +766,7 @@ int sun6i_csi_bridge_setup(struct sun6i_csi_device *csi_dev)
> {
> struct device *dev = csi_dev->dev;
> struct sun6i_csi_bridge *bridge = &csi_dev->bridge;
> - struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;
> + struct v4l2_device *v4l2_dev = csi_dev->v4l2_dev;
> struct v4l2_subdev *subdev = &bridge->subdev;
> struct v4l2_async_notifier *notifier = &bridge->notifier;
> struct media_pad *pads = bridge->pads;
> @@ -793,7 +807,11 @@ int sun6i_csi_bridge_setup(struct sun6i_csi_device *csi_dev)
>
> /* V4L2 Subdev */
>
> - ret = v4l2_device_register_subdev(v4l2_dev, subdev);
> + if (csi_dev->isp_available)
> + ret = v4l2_async_register_subdev(subdev);
> + else
> + ret = v4l2_device_register_subdev(v4l2_dev, subdev);
> +
> if (ret) {
> dev_err(dev, "failed to register v4l2 subdev: %d\n", ret);
> goto error_media_entity;
> @@ -810,7 +828,10 @@ int sun6i_csi_bridge_setup(struct sun6i_csi_device *csi_dev)
> sun6i_csi_bridge_source_setup(csi_dev, &bridge->source_mipi_csi2,
> SUN6I_CSI_PORT_MIPI_CSI2, NULL);
>
> - ret = v4l2_async_nf_register(v4l2_dev, notifier);
> + if (csi_dev->isp_available)
> + ret = v4l2_async_subdev_nf_register(subdev, notifier);
> + else
> + ret = v4l2_async_nf_register(v4l2_dev, notifier);
> if (ret) {
> dev_err(dev, "failed to register v4l2 async notifier: %d\n",
> ret);
> @@ -822,7 +843,10 @@ int sun6i_csi_bridge_setup(struct sun6i_csi_device *csi_dev)
> error_v4l2_async_notifier:
> v4l2_async_nf_cleanup(notifier);
>
> - v4l2_device_unregister_subdev(subdev);
> + if (csi_dev->isp_available)
> + v4l2_async_unregister_subdev(subdev);
> + else
> + v4l2_device_unregister_subdev(subdev);
>
> error_media_entity:
> media_entity_cleanup(&subdev->entity);
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> index c9e7526b84c4..69ea1cbaea0c 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> @@ -570,7 +570,7 @@ static int sun6i_csi_capture_buffer_prepare(struct vb2_buffer *buffer)
> {
> struct sun6i_csi_device *csi_dev = vb2_get_drv_priv(buffer->vb2_queue);
> struct sun6i_csi_capture *capture = &csi_dev->capture;
> - struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;
> + struct v4l2_device *v4l2_dev = csi_dev->v4l2_dev;
> struct vb2_v4l2_buffer *v4l2_buffer = to_vb2_v4l2_buffer(buffer);
> unsigned long size = capture->format.fmt.pix.sizeimage;
>
> @@ -889,7 +889,7 @@ static int sun6i_csi_capture_link_validate(struct media_link *link)
> struct video_device *video_dev =
> media_entity_to_video_device(link->sink->entity);
> struct sun6i_csi_device *csi_dev = video_get_drvdata(video_dev);
> - struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;
> + struct v4l2_device *v4l2_dev = csi_dev->v4l2_dev;
> const struct sun6i_csi_capture_format *capture_format;
> const struct sun6i_csi_bridge_format *bridge_format;
> unsigned int capture_width, capture_height;
> @@ -971,7 +971,7 @@ int sun6i_csi_capture_setup(struct sun6i_csi_device *csi_dev)
> {
> struct sun6i_csi_capture *capture = &csi_dev->capture;
> struct sun6i_csi_capture_state *state = &capture->state;
> - struct v4l2_device *v4l2_dev = &csi_dev->v4l2.v4l2_dev;
> + struct v4l2_device *v4l2_dev = csi_dev->v4l2_dev;
> struct v4l2_subdev *bridge_subdev = &csi_dev->bridge.subdev;
> struct video_device *video_dev = &capture->video_dev;
> struct vb2_queue *queue = &capture->queue;
> @@ -980,6 +980,10 @@ int sun6i_csi_capture_setup(struct sun6i_csi_device *csi_dev)
> struct v4l2_pix_format *pix_format = &format->fmt.pix;
> int ret;
>
> + /* This may happen with multiple bridge notifier bound calls. */
> + if (state->setup)
> + return 0;
> +
> /* State */
>
> INIT_LIST_HEAD(&state->queue);
> @@ -1055,6 +1059,7 @@ int sun6i_csi_capture_setup(struct sun6i_csi_device *csi_dev)
> ret = media_create_pad_link(&bridge_subdev->entity,
> SUN6I_CSI_BRIDGE_PAD_SOURCE,
> &video_dev->entity, 0,
> + csi_dev->isp_available ? 0 :
> MEDIA_LNK_FL_ENABLED |
> MEDIA_LNK_FL_IMMUTABLE);
> if (ret < 0) {
> @@ -1065,6 +1070,8 @@ int sun6i_csi_capture_setup(struct sun6i_csi_device *csi_dev)
> goto error_video_device;
> }
>
> + state->setup = true;
> +
> return 0;
>
> error_video_device:
> @@ -1083,7 +1090,13 @@ void sun6i_csi_capture_cleanup(struct sun6i_csi_device *csi_dev)
> struct sun6i_csi_capture *capture = &csi_dev->capture;
> struct video_device *video_dev = &capture->video_dev;
>
> + /* This may happen if async registration failed to complete. */
> + if (!capture->state.setup)
> + return;
> +
> vb2_video_unregister_device(video_dev);
> media_entity_cleanup(&video_dev->entity);
> mutex_destroy(&capture->lock);
> +
> + capture->state.setup = false;
> }
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.h b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.h
> index 29893cf96f6b..3ee5ccefbd10 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.h
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.h
> @@ -45,6 +45,7 @@ struct sun6i_csi_capture_state {
>
> unsigned int sequence;
> bool streaming;
> + bool setup;
> };
>
> struct sun6i_csi_capture {

--
Regards,

Laurent Pinchart