[libcamera-devel] [PATCH v7 12/12] pipeline: ipa: raspberrypi: Handle any externally allocated FrameBuffer

Niklas Söderlund niklas.soderlund at ragnatech.se
Tue Sep 15 16:55:34 CEST 2020


Hi Naush, Kieran,

On 2020-09-15 14:59:23 +0100, Kieran Bingham wrote:
> Hi Naush,
> 
> On 08/09/2020 08:49, Naushir Patuck wrote:
> > Handle the case where a FrameBuffer that has been externally allocated
> > (i.e. not through the v4l2 video device) is passed into a Request.
> > 
> > We must store the buffer pointer in the stream internal buffer list to
> > identify when used.
> > 
> > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > ---
> >  include/libcamera/ipa/raspberrypi.h           | 11 ++--
> >  src/ipa/raspberrypi/raspberrypi.cpp           |  6 +-
> >  .../pipeline/raspberrypi/raspberrypi.cpp      | 64 +++++++++++++------
> >  .../pipeline/raspberrypi/rpi_stream.cpp       | 30 ++++++++-
> >  .../pipeline/raspberrypi/rpi_stream.h         |  3 +
> >  5 files changed, 85 insertions(+), 29 deletions(-)
> > 
> > diff --git a/include/libcamera/ipa/raspberrypi.h b/include/libcamera/ipa/raspberrypi.h
> > index 262fc6f3..dd6ebeac 100644
> > --- a/include/libcamera/ipa/raspberrypi.h
> > +++ b/include/libcamera/ipa/raspberrypi.h
> > @@ -28,11 +28,12 @@ enum RPiOperations {
> >  	RPI_IPA_EVENT_QUEUE_REQUEST,
> >  };
> >  
> > -enum RPiIpaMask {
> > -	ID		= 0x0ffff,
> > -	STATS		= 0x10000,
> > -	EMBEDDED_DATA	= 0x20000,
> > -	BAYER_DATA	= 0x40000
> > +enum RPiBufferMask {
> > +	ID		= 0x00ffff,
> > +	STATS		= 0x010000,
> > +	EMBEDDED_DATA	= 0x020000,
> > +	BAYER_DATA	= 0x040000,
> > +	EXTERNAL_BUFFER	= 0x100000,
> >  };
> >  
> >  /* Size of the LS grid allocation. */
> > diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> > index 688d2efc..0555cc4e 100644
> > --- a/src/ipa/raspberrypi/raspberrypi.cpp
> > +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> > @@ -352,7 +352,7 @@ void IPARPi::processEvent(const IPAOperationData &event)
> >  
> >  		IPAOperationData op;
> >  		op.operation = RPI_IPA_ACTION_STATS_METADATA_COMPLETE;
> > -		op.data = { bufferId & RPiIpaMask::ID };
> > +		op.data = { bufferId & RPiBufferMask::ID };
> >  		op.controls = { libcameraMetadata_ };
> >  		queueFrameAction.emit(0, op);
> >  		break;
> > @@ -373,7 +373,7 @@ void IPARPi::processEvent(const IPAOperationData &event)
> >  		/* Ready to push the input buffer into the ISP. */
> >  		IPAOperationData op;
> >  		op.operation = RPI_IPA_ACTION_RUN_ISP;
> > -		op.data = { bayerbufferId & RPiIpaMask::ID };
> > +		op.data = { bayerbufferId & RPiBufferMask::ID };
> >  		queueFrameAction.emit(0, op);
> >  		break;
> >  	}
> > @@ -700,7 +700,7 @@ void IPARPi::returnEmbeddedBuffer(unsigned int bufferId)
> >  {
> >  	IPAOperationData op;
> >  	op.operation = RPI_IPA_ACTION_EMBEDDED_COMPLETE;
> > -	op.data = { bufferId & RPiIpaMask::ID };
> > +	op.data = { bufferId & RPiBufferMask::ID };
> >  	queueFrameAction.emit(0, op);
> >  }
> >  
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index 5621f182..f5e0d1cd 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -151,6 +151,7 @@ public:
> >  
> >  	void clearIncompleteRequests();
> >  	void handleStreamBuffer(FrameBuffer *buffer, RPi::RPiStream *stream);
> > +	void handleExternalBuffer(FrameBuffer *buffer, RPi::RPiStream *stream);
> >  	void handleState();
> >  
> >  	CameraSensor *sensor_;
> > @@ -725,23 +726,32 @@ int PipelineHandlerRPi::queueRequestDevice(Camera *camera, Request *request)
> >  
> >  	/* Push all buffers supplied in the Request to the respective streams. */
> >  	for (auto stream : data->streams_) {
> > -		if (stream->isExternal()) {
> > -			FrameBuffer *buffer = request->findBuffer(stream);
> > +		if (!stream->isExternal())
> > +			continue;
> > +
> > +		FrameBuffer *buffer = request->findBuffer(stream);
> > +		if (buffer && stream->getBufferId(buffer) == -1) {
> >  			/*
> > -			 * If no buffer is provided by the request for this stream, we
> > -			 * queue a nullptr to the stream to signify that it must use an
> > -			 * internally allocated buffer for this capture request. This
> > -			 * buffer will not be given back to the application, but is used
> > -			 * to support the internal pipeline flow.
> > -			 *
> > -			 * The below queueBuffer() call will do nothing if there are not
> > -			 * enough internal buffers allocated, but this will be handled by
> > -			 * queuing the request for buffers in the RPiStream object.
> > +			 * This buffer is not recognised, so it must have been allocated
> > +			 * outside the v4l2 device. Store it in the stream buffer list
> > +			 * so we can track it.
> >  			 */
> > -			int ret = stream->queueBuffer(buffer);
> > -			if (ret)
> > -				return ret;
> > +			stream->setExternalBuffer(buffer);
> >  		}
> > +		/*
> > +		 * If no buffer is provided by the request for this stream, we
> > +		 * queue a nullptr to the stream to signify that it must use an
> > +		 * internally allocated buffer for this capture request. This
> > +		 * buffer will not be given back to the application, but is used
> > +		 * to support the internal pipeline flow.
> > +		 *
> > +		 * The below queueBuffer() call will do nothing if there are not
> > +		 * enough internal buffers allocated, but this will be handled by
> > +		 * queuing the request for buffers in the RPiStream object.
> > +		 */
> > +		int ret = stream->queueBuffer(buffer);
> > +		if (ret)
> > +			return ret;
> >  	}
> >  
> >  	/* Push the request to the back of the queue. */
> > @@ -915,8 +925,8 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
> >  	 * Pass the stats and embedded data buffers to the IPA. No other
> >  	 * buffers need to be passed.
> >  	 */
> > -	mapBuffers(camera, data->isp_[Isp::Stats].getBuffers(), RPiIpaMask::STATS);
> > -	mapBuffers(camera, data->unicam_[Unicam::Embedded].getBuffers(), RPiIpaMask::EMBEDDED_DATA);
> > +	mapBuffers(camera, data->isp_[Isp::Stats].getBuffers(), RPiBufferMask::STATS);
> > +	mapBuffers(camera, data->unicam_[Unicam::Embedded].getBuffers(), RPiBufferMask::EMBEDDED_DATA);
> >  
> >  	return 0;
> >  }
> > @@ -1219,7 +1229,7 @@ void RPiCameraData::ispOutputDequeue(FrameBuffer *buffer)
> >  	if (stream == &isp_[Isp::Stats]) {
> >  		IPAOperationData op;
> >  		op.operation = RPI_IPA_EVENT_SIGNAL_STAT_READY;
> > -		op.data = { RPiIpaMask::STATS | static_cast<unsigned int>(index) };
> > +		op.data = { RPiBufferMask::STATS | static_cast<unsigned int>(index) };
> >  		ipa_->processEvent(op);
> >  	} else {
> >  		/* Any other ISP output can be handed back to the application now. */
> > @@ -1293,6 +1303,11 @@ void RPiCameraData::handleStreamBuffer(FrameBuffer *buffer, RPi::RPiStream *stre
> >  		Request *request = requestQueue_.front();
> >  
> >  		if (!dropFrameCount_ && request->findBuffer(stream) == buffer) {
> > +			/*
> > +			 * Check if this is an externally provided buffer, and if
> > +			 * so, we must stop tracking it in the pipeline handler.
> > +			 */
> > +			handleExternalBuffer(buffer, stream);
> >  			/*
> >  			 * Tag the buffer as completed, returning it to the
> >  			 * application.
> > @@ -1311,6 +1326,17 @@ void RPiCameraData::handleStreamBuffer(FrameBuffer *buffer, RPi::RPiStream *stre
> >  	}
> >  }
> >  
> > +void RPiCameraData::handleExternalBuffer(FrameBuffer *buffer, RPi::RPiStream *stream)
> > +{
> > +	unsigned int id = stream->getBufferId(buffer);
> > +
> > +	if (!(id & RPiBufferMask::EXTERNAL_BUFFER))
> > +		return;
> > +
> > +	/* Stop the Stream object from tracking the buffer. */
> > +	stream->removeExternalBuffer(buffer);
> > +}
> > +
> >  void RPiCameraData::handleState()
> >  {
> >  	switch (state_) {
> > @@ -1443,8 +1469,8 @@ void RPiCameraData::tryRunPipeline()
> >  			<< " Embedded buffer id: " << embeddedIndex;
> >  
> >  	op.operation = RPI_IPA_EVENT_SIGNAL_ISP_PREPARE;
> > -	op.data = { RPiIpaMask::EMBEDDED_DATA | embeddedIndex,
> > -		    RPiIpaMask::BAYER_DATA | bayerIndex };
> > +	op.data = { RPiBufferMask::EMBEDDED_DATA | embeddedIndex,
> > +		    RPiBufferMask::BAYER_DATA | bayerIndex };
> >  	ipa_->processEvent(op);
> >  }
> >  
> > diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> > index 879e25ba..c09f14c9 100644
> > --- a/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.cpp
> > @@ -6,6 +6,8 @@
> >   */
> >  #include "rpi_stream.h"
> >  
> > +#include <libcamera/ipa/raspberrypi.h>
> > +
> >  #include "libcamera/internal/log.h"
> >  
> >  namespace libcamera {
> > @@ -44,8 +46,13 @@ bool RPiStream::isExternal() const
> >  
> >  void RPiStream::setExportedBuffers(std::vector<std::unique_ptr<FrameBuffer>> *buffers)
> >  {
> > -	for (auto const &buffer : *buffers)
> > -		bufferMap_.emplace(id_++, buffer.get());
> > +	/* Ensure we are using a sensible number of buffers. */
> > +	ASSERT(id_ < RPiBufferMask::ID);
> > +
> > +	for (auto const &buffer : *buffers) {
> > +		bufferMap_.emplace(id_ & RPiBufferMask::ID, buffer.get());
> > +		id_++;
> > +	}
> 
> I half wonder if that assert shouldn't come 'after' the updates to the
> bufferMap to catch if the id_ has overflowed after increase.
> 
> But maybe this is a tiny corner case and not expected anyway.
> 
> 
> >  }
> >  
> >  const BufferMap &RPiStream::getBuffers() const
> > @@ -68,6 +75,25 @@ int RPiStream::getBufferId(FrameBuffer *buffer) const
> >  	return it->first;
> >  }
> >  
> > +void RPiStream::setExternalBuffer(FrameBuffer *buffer)
> > +{
> > +	/* Ensure we are using a sensible number of buffers. */
> > +	ASSERT(id_ < RPiBufferMask::ID);
> > +
> > +	bufferMap_.emplace(RPiBufferMask::EXTERNAL_BUFFER | (id_ & RPiBufferMask::ID),
> > +			   buffer);
> > +	id_++;
> 
> Oh, ... is there no reduction of the id_?
> 
> What happens if an application continually provides an external buffer
> ... won't that constantly increase this id_ with every frame?
> 
> Are the ID's re-used? or is it just that the stream doesn't generate a
> new ID for each usage of an external buffer (i.e. it really would have
> to be more than 65535 entirely different buffers...)
> 
> I guess this can be easily validated by setting RPiBufferMask::ID to
> 0xFF or even 0xF to see if it hits any assertions quickly
> 
> As long as this doesn't leak and cause an assertion/overflow after
> 0xFFFF/RPiBufferMask::ID requests are queued ...

This is a very good observation that I missed in my review. Good thing 
you looked at it as I was about to merge this series.

Naush would it be possible to rework this logic slightly to makesure the 
id_ used can rollover while at the same time is not overwriting an 
existing mapping? With this solved I think we are ready to merge this 
series \o/.

> 
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> > +}
> > +
> > +void RPiStream::removeExternalBuffer(FrameBuffer *buffer)
> > +{
> > +	int id = getBufferId(buffer);
> > +
> > +	/* Ensure we have this buffer in the stream, and it is marked external. */
> > +	ASSERT(id != -1 && (id & RPiBufferMask::EXTERNAL_BUFFER));
> > +	bufferMap_.erase(id);
> > +}
> > +
> >  int RPiStream::prepareBuffers(unsigned int count)
> >  {
> >  	int ret;
> > diff --git a/src/libcamera/pipeline/raspberrypi/rpi_stream.h b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> > index ed517c22..8b23c4b2 100644
> > --- a/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> > +++ b/src/libcamera/pipeline/raspberrypi/rpi_stream.h
> > @@ -51,6 +51,9 @@ public:
> >  	const BufferMap &getBuffers() const;
> >  	int getBufferId(FrameBuffer *buffer) const;
> >  
> > +	void setExternalBuffer(FrameBuffer *buffer);
> > +	void removeExternalBuffer(FrameBuffer *buffer);
> > +
> >  	int prepareBuffers(unsigned int count);
> >  	int queueBuffer(FrameBuffer *buffer);
> >  	void returnBuffer(FrameBuffer *buffer);
> > 
> 
> -- 
> Regards
> --
> Kieran
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel at lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel

-- 
Regards,
Niklas Söderlund


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