[libcamera-devel] [PATCH 2/2] libcamera: ipu3: Create CIO2 V4L2 devices

[Jacopo Mondi]

Hi Niklas
   thanks for review

On Thu, Jan 24, 2019 at 08:06:30PM +0100, Niklas Söderlund wrote:
> Hi Jacopo,
>
> Thanks for your work.
>
> On 2019-01-24 12:30:20 +0100, Jacopo Mondi wrote:
> > Create V4L2 devices for the CIO2 capture video nodes and associate them
> > with the camera they are part of.
> >
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >  src/libcamera/pipeline/ipu3/ipu3.cpp | 50 ++++++++++++++++++++++++++++
> >  1 file changed, 50 insertions(+)
> >
> > diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > index 8cbc10a..9f5a40f 100644
> > --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> > +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> > @@ -15,6 +15,8 @@
> >  #include "log.h"
> >  #include "media_device.h"
> >  #include "pipeline_handler.h"
> > +#include "utils.h"
> > +#include "v4l2_device.h"
> >
> >  namespace libcamera {
> >
> > @@ -29,9 +31,19 @@ public:
> >  	bool match(CameraManager *manager, DeviceEnumerator *enumerator);
> >
> >  private:
> > +	class IPU3CameraData : public CameraData
> > +	{
> > +	public:
> > +		IPU3CameraData()
> > +			: dev_(nullptr) { }
> > +		~IPU3CameraData() { delete dev_; }
> > +		V4L2Device *dev_;
> > +	};
> > +
> >  	MediaDevice *cio2_;
> >  	MediaDevice *imgu_;
> >
> > +	V4L2Device *createVideoDevice(unsigned int id);
> >  	void registerCameras(CameraManager *manager);
> >  };
> >
> > @@ -122,6 +134,24 @@ error_release_mdev:
> >  	return false;
> >  }
> >
> > +/* Create video devices for the CIO2 unit associated with a camera. */
> > +V4L2Device *PipelineHandlerIPU3::createVideoDevice(unsigned int id)
> > +{
> > +	std::string cio2Name = "ipu3-cio2 " + std::to_string(id);
> > +	MediaEntity *cio2 = cio2_->getEntityByName(cio2Name);
> > +	if (!cio2)
> > +		return nullptr;
> > +
> > +	V4L2Device *dev = new V4L2Device(*cio2);
> > +	if (dev->open()) {
> > +		delete dev;
> > +		return nullptr;
> > +	}
> > +	dev->close();
> > +
> > +	return dev;
> > +}
> > +
> >  /*
> >   * Cameras are created associating an image sensor (represented by a
> >   * media entity with function MEDIA_ENT_F_CAM_SENSOR) to one of the four
> > @@ -172,6 +202,26 @@ void PipelineHandlerIPU3::registerCameras(CameraManager *manager)
> >
> >  		std::string cameraName = sensor->name() + " " + std::to_string(id);
> >  		std::shared_ptr<Camera> camera = Camera::create(cameraName);
> > +
> > +		setCameraData(camera.get(),
> > +			      std::move(utils::make_unique<IPU3CameraData>()));
> > +		IPU3CameraData *data =
> > +			reinterpret_cast<IPU3CameraData *>(cameraData(camera.get()));
>
> I'm not saying this is not needed, only that it looks a bit complex to
> my feeble mind. Could you educate me why the following would not work?
>
>     IPU3CameraData *data = new IPU3CameraData();
>     data->dev_ = videoDev;
>
>     setCameraData(camera.get(), data);

setCameraData wants a unique_ptr. On the reason why we're passing it
by value (hence the std::move() ) instead than by reference and move()
inside the function see the discussion on v1. Basically, it makes
clear that after setCameraData() the local reference it's not
valid anymore.

That said, I could indeed have created a unique_ptr<> from an already
existing reference, instead of using std::make_unique.

What I have now looks like the following:

		V4L2Device *videoDev = createVideoDevice(id);
		if (!videoDev) {
			LOG(IPU3, Error)
				<< "Failed to register camera["
				<< numCameras << "] \"" << cameraName << "\"";
			continue;
		}

		IPU3CameraData *data = new IPU3CameraData(*videoDev);
		setCameraData(camera.get(),
			      std::move(std::unique_ptr<IPU3CameraData>(data)));
		manager->addCamera(std::move(camera));

Which is in my opinion nicer and equally safe. Thanks a lot for pointing
this out. Is it any better?

Thanks
  j

>
> Apart from this I think this commit looks good.
>
> > +
> > +		/*
> > +		 * If V4L2 device creation fails, the Camera instance won't be
> > +		 * registered. The 'camera' shared pointer goes out of scope
> > +		 * and deletes the Camera it manages.
> > +		 */
> > +		V4L2Device *videoDev = createVideoDevice(id);
> > +		if (!videoDev) {
> > +			LOG(IPU3, Error)
> > +				<< "Failed to register camera["
> > +				<< numCameras << "] \"" << cameraName << "\"";
> > +			continue;
> > +		}
> > +
> > +		data->dev_ = videoDev;
> >  		manager->addCamera(std::move(camera));
> >
> >  		LOG(IPU3, Info)
> > --
> > 2.20.1
> >
> > _______________________________________________
> > libcamera-devel mailing list
> > libcamera-devel at lists.libcamera.org
> > https://lists.libcamera.org/listinfo/libcamera-devel
>
> --
> Regards,
> Niklas Söderlund
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <https://lists.libcamera.org/pipermail/libcamera-devel/attachments/20190124/10ddffd1/attachment.sig>