Re: [PATCH v7 8/8] media: vsp1: Move video configuration to a cached dlb

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Kieran,

Thank you for the patch.

On Thursday, 8 March 2018 02:05:31 EEST Kieran Bingham wrote:
> We are now able to configure a pipeline directly into a local display
> list body. Take advantage of this fact, and create a cacheable body to
> store the configuration of the pipeline in the video object.
> 
> vsp1_video_pipeline_run() is now the last user of the pipe->dl object.
> Convert this function to use the cached video->config body and obtain a
> local display list reference.
> 
> Attach the video->config body to the display list when needed before
> committing to hardware.
> 
> The pipe object is marked as un-configured when resuming from a suspend.
> This ensures that when the hardware is reset - our cached configuration
> will be re-attached to the next committed DL.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> ---
> 
> v3:
>  - 's/fragment/body/', 's/fragments/bodies/'
>  - video dlb cache allocation increased from 2 to 3 dlbs
> 
> Our video DL usage now looks like the below output:
> 
> dl->body0 contains our disposable runtime configuration. Max 41.
> dl_child->body0 is our partition specific configuration. Max 12.
> dl->bodies shows our constant configuration and LUTs.
> 
>   These two are LUT/CLU:
>      * dl->bodies[x]->num_entries 256 / max 256
>      * dl->bodies[x]->num_entries 4914 / max 4914
> 
> Which shows that our 'constant' configuration cache is currently
> utilised to a maximum of 64 entries.
> 
> trace-cmd report | \
>     grep max | sed 's/.*vsp1_dl_list_commit://g' | sort | uniq;
> 
>   dl->body0->num_entries 13 / max 128
>   dl->body0->num_entries 14 / max 128
>   dl->body0->num_entries 16 / max 128
>   dl->body0->num_entries 20 / max 128
>   dl->body0->num_entries 27 / max 128
>   dl->body0->num_entries 34 / max 128
>   dl->body0->num_entries 41 / max 128
>   dl_child->body0->num_entries 10 / max 128
>   dl_child->body0->num_entries 12 / max 128
>   dl->bodies[x]->num_entries 15 / max 128
>   dl->bodies[x]->num_entries 16 / max 128
>   dl->bodies[x]->num_entries 17 / max 128
>   dl->bodies[x]->num_entries 18 / max 128
>   dl->bodies[x]->num_entries 20 / max 128
>   dl->bodies[x]->num_entries 21 / max 128
>   dl->bodies[x]->num_entries 256 / max 256
>   dl->bodies[x]->num_entries 31 / max 128
>   dl->bodies[x]->num_entries 32 / max 128
>   dl->bodies[x]->num_entries 39 / max 128
>   dl->bodies[x]->num_entries 40 / max 128
>   dl->bodies[x]->num_entries 47 / max 128
>   dl->bodies[x]->num_entries 48 / max 128
>   dl->bodies[x]->num_entries 4914 / max 4914
>   dl->bodies[x]->num_entries 55 / max 128
>   dl->bodies[x]->num_entries 56 / max 128
>   dl->bodies[x]->num_entries 63 / max 128
>   dl->bodies[x]->num_entries 64 / max 128

This might be useful to capture in the main part of the commit message.

> v4:
>  - Adjust pipe configured flag to be reset on resume rather than suspend
>  - rename dl_child, dl_next
> 
>  drivers/media/platform/vsp1/vsp1_pipe.c  |  7 +++-
>  drivers/media/platform/vsp1/vsp1_pipe.h  |  4 +-
>  drivers/media/platform/vsp1/vsp1_video.c | 67 ++++++++++++++++---------
>  drivers/media/platform/vsp1/vsp1_video.h |  2 +-
>  4 files changed, 54 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/media/platform/vsp1/vsp1_pipe.c
> b/drivers/media/platform/vsp1/vsp1_pipe.c index 5012643583b6..fa445b1a2e38
> 100644
> --- a/drivers/media/platform/vsp1/vsp1_pipe.c
> +++ b/drivers/media/platform/vsp1/vsp1_pipe.c
> @@ -249,6 +249,7 @@ void vsp1_pipeline_run(struct vsp1_pipeline *pipe)
>  		vsp1_write(vsp1, VI6_CMD(pipe->output->entity.index),
>  			   VI6_CMD_STRCMD);
>  		pipe->state = VSP1_PIPELINE_RUNNING;
> +		pipe->configured = true;
>  	}
> 
>  	pipe->buffers_ready = 0;
> @@ -470,6 +471,12 @@ void vsp1_pipelines_resume(struct vsp1_device *vsp1)
>  			continue;
> 
>  		spin_lock_irqsave(&pipe->irqlock, flags);
> +		/*
> +		 * The hardware may have been reset during a suspend and will
> +		 * need a full reconfiguration
> +		 */

s/reconfiguration/reconfiguration./

> +		pipe->configured = false;
> +

Where does that full reconfiguration occur, given that the vsp1_pipeline_run() 
right below sets pipe->configured to true without performing reconfiguration ?

>  		if (vsp1_pipeline_ready(pipe))
>  			vsp1_pipeline_run(pipe);
>  		spin_unlock_irqrestore(&pipe->irqlock, flags);
> diff --git a/drivers/media/platform/vsp1/vsp1_pipe.h
> b/drivers/media/platform/vsp1/vsp1_pipe.h index 90d29492b9b9..e7ad6211b4d0
> 100644
> --- a/drivers/media/platform/vsp1/vsp1_pipe.h
> +++ b/drivers/media/platform/vsp1/vsp1_pipe.h
> @@ -90,6 +90,7 @@ struct vsp1_partition {
>   * @irqlock: protects the pipeline state
>   * @state: current state
>   * @wq: wait queue to wait for state change completion
> + * @configured: flag determining if the hardware has run since reset
>   * @frame_end: frame end interrupt handler
>   * @lock: protects the pipeline use count and stream count
>   * @kref: pipeline reference count
> @@ -117,6 +118,7 @@ struct vsp1_pipeline {
>  	spinlock_t irqlock;
>  	enum vsp1_pipeline_state state;
>  	wait_queue_head_t wq;
> +	bool configured;
> 
>  	void (*frame_end)(struct vsp1_pipeline *pipe, bool completed);
> 
> @@ -143,8 +145,6 @@ struct vsp1_pipeline {
>  	 */
>  	struct list_head entities;
> 
> -	struct vsp1_dl_list *dl;
> -

You should remove the corresponding line from the structure documentation.

>  	unsigned int partitions;
>  	struct vsp1_partition *partition;
>  	struct vsp1_partition *part_table;
> diff --git a/drivers/media/platform/vsp1/vsp1_video.c
> b/drivers/media/platform/vsp1/vsp1_video.c index b47708660e53..96d9872667d9
> 100644
> --- a/drivers/media/platform/vsp1/vsp1_video.c
> +++ b/drivers/media/platform/vsp1/vsp1_video.c
> @@ -394,37 +394,43 @@ static void vsp1_video_pipeline_run_partition(struct
> vsp1_pipeline *pipe, static void vsp1_video_pipeline_run(struct
> vsp1_pipeline *pipe)
>  {
>  	struct vsp1_device *vsp1 = pipe->output->entity.vsp1;
> +	struct vsp1_video *video = pipe->output->video;
>  	unsigned int partition;
> +	struct vsp1_dl_list *dl;
> +
> +	dl = vsp1_dl_list_get(pipe->output->dlm);
> 
> -	if (!pipe->dl)
> -		pipe->dl = vsp1_dl_list_get(pipe->output->dlm);
> +	/* Attach our pipe configuration to fully initialise the hardware */

s/hardware/hardware./

There are other similar comments in this patch.

> +	if (!pipe->configured) {
> +		vsp1_dl_list_add_body(dl, video->pipe_config);
> +		pipe->configured = true;
> +	}
> 
>  	/* Run the first partition */
> -	vsp1_video_pipeline_run_partition(pipe, pipe->dl, 0);
> +	vsp1_video_pipeline_run_partition(pipe, dl, 0);
> 
>  	/* Process consecutive partitions as necessary */
>  	for (partition = 1; partition < pipe->partitions; ++partition) {
> -		struct vsp1_dl_list *dl;
> +		struct vsp1_dl_list *dl_next;
> 
> -		dl = vsp1_dl_list_get(pipe->output->dlm);
> +		dl_next = vsp1_dl_list_get(pipe->output->dlm);
> 
>  		/*
>  		 * An incomplete chain will still function, but output only
>  		 * the partitions that had a dl available. The frame end
>  		 * interrupt will be marked on the last dl in the chain.
>  		 */
> -		if (!dl) {
> +		if (!dl_next) {
>  			dev_err(vsp1->dev, "Failed to obtain a dl list. Frame will be
> incomplete\n"); break;
>  		}
> 
> -		vsp1_video_pipeline_run_partition(pipe, dl, partition);
> -		vsp1_dl_list_add_chain(pipe->dl, dl);
> +		vsp1_video_pipeline_run_partition(pipe, dl_next, partition);
> +		vsp1_dl_list_add_chain(dl, dl_next);
>  	}
> 
>  	/* Complete, and commit the head display list. */
> -	vsp1_dl_list_commit(pipe->dl);
> -	pipe->dl = NULL;
> +	vsp1_dl_list_commit(dl);
> 
>  	vsp1_pipeline_run(pipe);
>  }
> @@ -790,8 +796,8 @@ static void vsp1_video_buffer_queue(struct vb2_buffer
> *vb)
> 
>  static int vsp1_video_setup_pipeline(struct vsp1_pipeline *pipe)
>  {
> +	struct vsp1_video *video = pipe->output->video;
>  	struct vsp1_entity *entity;
> -	struct vsp1_dl_body *dlb;
>  	int ret;
> 
>  	/* Determine this pipelines sizes for image partitioning support. */
> @@ -799,14 +805,6 @@ static int vsp1_video_setup_pipeline(struct
> vsp1_pipeline *pipe) if (ret < 0)
>  		return ret;
> 
> -	/* Prepare the display list. */
> -	pipe->dl = vsp1_dl_list_get(pipe->output->dlm);
> -	if (!pipe->dl)
> -		return -ENOMEM;
> -
> -	/* Retrieve the default DLB from the list */
> -	dlb = vsp1_dl_list_get_body0(pipe->dl);
> -
>  	if (pipe->uds) {
>  		struct vsp1_uds *uds = to_uds(&pipe->uds->subdev);
> 
> @@ -828,11 +826,20 @@ static int vsp1_video_setup_pipeline(struct
> vsp1_pipeline *pipe) }
>  	}
> 
> +	/* Obtain a clean body from our pool */
> +	video->pipe_config = vsp1_dl_body_get(video->dlbs);
> +	if (!video->pipe_config)
> +		return -ENOMEM;
> +
> +	/* Configure the entities into our cached pipe configuration */
>  	list_for_each_entry(entity, &pipe->entities, list_pipe) {
> -		vsp1_entity_route_setup(entity, pipe, dlb);
> -		vsp1_entity_configure_stream(entity, pipe, dlb);
> +		vsp1_entity_route_setup(entity, pipe, video->pipe_config);
> +		vsp1_entity_configure_stream(entity, pipe, video->pipe_config);
>  	}
> 
> +	/* Ensure that our cached configuration is updated in the next DL */
> +	pipe->configured = false;

Quoting my comment to a previous version, and your reply to it which I have 
failed to answer,

> > I'm tempted to move this at pipeline stop time (either to
> > vsp1_video_stop_streaming() right after the vsp1_pipeline_stop() call, or
> > in vsp1_pipeline_stop() itself), possibly with a WARN_ON() here to catch
> > bugs in the driver.
> 
> Do you mean just setting the flag? or the pipe_configuration? This is a
> setup task - not a stop task ... ? We are doing this as part of
> vsp1_video_start_streaming().

I meant just setting the configured flag back to false.

> IMO, The flag should only be updated after the configuration has been
> updated to signal that the new configuration should be written out to the
> hardware.
> 
> Unless you mean to mark the pipe->configured = false; at
> vsp1_pipeline_stop() time because we reset the pipe to halt it ?\0

That's the idea, yes. And now that I think about it again, we could also set 
pipe->configured to false in vsp1_video_cleanup_pipeline() right after the 
vsp1_dl_body_put() call.

What bothers me here is that the pipe->configured flag is handled both in 
vsp1_pipe.c and vsp1_video.c. Coupled with my above comment about the full 
reconfiguration at resume time, I think we might not be abstracting this as we 
should. I wonder whether it would be possible to either make the flag local to 
vsp1_pipe.c, or local to vsp1_video.c and move it from the pipeline object to 
the video object. My gut feeling right now (and it might be too late to trust 
it) is that, as the pipe_config object is stored in vsp1_video, so should the 
configured flag.

Please feel free to challenge this.

> +
>  	return 0;
>  }
> 
> @@ -842,6 +849,9 @@ static void vsp1_video_cleanup_pipeline(struct
> vsp1_pipeline *pipe) struct vsp1_vb2_buffer *buffer;
>  	unsigned long flags;
> 
> +	/* Release any cached configuration */
> +	vsp1_dl_body_put(video->pipe_config);
> +
>  	/* Remove all buffers from the IRQ queue. */
>  	spin_lock_irqsave(&video->irqlock, flags);
>  	list_for_each_entry(buffer, &video->irqqueue, queue)
> @@ -918,9 +928,6 @@ static void vsp1_video_stop_streaming(struct vb2_queue
> *vq) ret = vsp1_pipeline_stop(pipe);
>  		if (ret == -ETIMEDOUT)
>  			dev_err(video->vsp1->dev, "pipeline stop timeout\n");
> -
> -		vsp1_dl_list_put(pipe->dl);
> -		pipe->dl = NULL;
>  	}
>  	mutex_unlock(&pipe->lock);
> 
> @@ -1240,6 +1247,16 @@ struct vsp1_video *vsp1_video_create(struct
> vsp1_device *vsp1, goto error;
>  	}
> 
> +	/*
> +	 * Utilise a body pool to cache the constant configuration of the
> +	 * pipeline object.
> +	 */
> +	video->dlbs = vsp1_dl_body_pool_create(vsp1, 3, 128, 0);
> +	if (!video->dlbs) {
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
>  	return video;
> 
>  error:
> @@ -1249,6 +1266,8 @@ struct vsp1_video *vsp1_video_create(struct
> vsp1_device *vsp1,
> 
>  void vsp1_video_cleanup(struct vsp1_video *video)
>  {
> +	vsp1_dl_body_pool_destroy(video->dlbs);
> +
>  	if (video_is_registered(&video->video))
>  		video_unregister_device(&video->video);
> 
> diff --git a/drivers/media/platform/vsp1/vsp1_video.h
> b/drivers/media/platform/vsp1/vsp1_video.h index 50ea7f02205f..e84f8ee902c1
> 100644
> --- a/drivers/media/platform/vsp1/vsp1_video.h
> +++ b/drivers/media/platform/vsp1/vsp1_video.h
> @@ -43,6 +43,8 @@ struct vsp1_video {
> 
>  	struct mutex lock;
> 
> +	struct vsp1_dl_body_pool *dlbs;
> +	struct vsp1_dl_body *pipe_config;
>  	unsigned int pipe_index;
> 
>  	struct vb2_queue queue;

-- 
Regards,

Laurent Pinchart