[libcamera-devel] [PATCH 02/10] libcamera: pipeline: simple: Add sink and source pads to entity data

[Laurent Pinchart]

Hi Kieran,

On Mon, Aug 16, 2021 at 03:41:21PM +0100, Kieran Bingham wrote:
> On 05/08/2021 23:24, Laurent Pinchart wrote:
> > Record the sink and source pads through which an entity is traversed in
> > the list of entities stored in the camera data. This prepares for
> > implementing mutually exclusive access to entities between cameras.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/libcamera/pipeline/simple/simple.cpp | 38 ++++++++++++++++++++----
> >  1 file changed, 32 insertions(+), 6 deletions(-)
> > 
> > diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> > index b29fff9820e5..e0695d052629 100644
> > --- a/src/libcamera/pipeline/simple/simple.cpp
> > +++ b/src/libcamera/pipeline/simple/simple.cpp
> > @@ -166,7 +166,22 @@ public:
> >  	}
> >  
> >  	struct Entity {
> > +		/* The media entity, always valid. */
> >  		MediaEntity *entity;
> > +		/*
> > +		 * The local sink pad connected to the upstream entity, null for
> > +		 * the camera sensor at the beginning of the pipeline.
> > +		 */
> > +		const MediaPad *sink;
> > +		/*
> > +		 * The local source pad connected to the downstream entity, null
> > +		 * for the video node at the end of the pipeline.
> > +		 */
> > +		const MediaPad *source;
> > +		/*
> > +		 * The link to the downstream entity, null for the video node at
> > +		 * the end of the pipeline.
> > +		 */
> >  		MediaLink *link;
> >  	};
> >  
> > @@ -288,16 +303,18 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
> >  	 * encoders and image converters, and will end in a CSI capture device.
> >  	 */
> >  	std::unordered_set<MediaEntity *> visited;
> > -	std::queue<MediaEntity *> queue;
> > +	std::queue<std::tuple<MediaEntity *, MediaPad *>> queue;
> >  
> >  	/* Remember at each entity where we came from. */
> >  	std::unordered_map<MediaEntity *, Entity> parents;
> >  	MediaEntity *entity = nullptr;
> >  
> > -	queue.push(sensor);
> > +	queue.push({ sensor, nullptr });
> >  
> >  	while (!queue.empty()) {
> > -		entity = queue.front();
> > +		MediaPad *sinkPad;
> > +
> > +		std::tie(entity, sinkPad) = queue.front();
> >  		queue.pop();
> >  
> >  		/* Found the capture device. */
> > @@ -317,8 +334,8 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
> >  			for (MediaLink *link : pad->links()) {
> >  				MediaEntity *next = link->sink()->entity();
> >  				if (visited.find(next) == visited.end()) {
> > -					queue.push(next);
> > -					parents.insert({ next, { entity, link } });
> > +					queue.push({ next, link->sink() });
> > +					parents.insert({ next, { entity, sinkPad, pad, link } });
> >  				}
> >  			}
> >  		}
> > @@ -349,7 +366,16 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
> >  	LOG(SimplePipeline, Debug)
> >  		<< "Found pipeline: "
> >  		<< utils::join(entities_, " -> ",
> > -			       [](const Entity &e) { return e.entity->name(); });
> > +			       [](const Entity &e) {
> > +				       std::string s = "[";
> > +				       if (e.sink)
> > +					       s += std::to_string(e.sink->index()) + "|";
> > +				       s += e.entity->name();
> > +				       if (e.source)
> > +					       s += "|" + std::to_string(e.source->index());
> > +				       s += "]";
> > +				       return s;
> > +			       });
> 
> An example of the changes to string formatting would be nice in the
> commit message, but not essential.

Note that this is just a debug message, not the main point of the patch
:-) I'll add

The debug message that displays detected pipelines now prints pads to
describe the pipeline more precisely:

[0:00:35.901275750] [260] DEBUG SimplePipeline simple.cpp:404 Found pipeline: [imx290 2-001a|0] -> [0|csis-32e40000.csi|1] -> [0|mxc_isi.0|1] -> [0|mxc_isi.0.capture]

> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> >  }
> >  
> >  int SimpleCameraData::init()

-- 
Regards,

Laurent Pinchart