libcamera: pipeline: Support importing buffers

Add support for importing external buffers in all pipeline handlers.

Use the stream memory type in the pipeline handlers during buffer
allocation to import buffers to or export buffers from the video device.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -69,8 +69,9 @@ public:
 	int configureOutput(ImgUOutput *output,
 			    const StreamConfiguration &cfg);
 
-	int importBuffers(BufferPool *pool);
+	int importInputBuffers(BufferPool *pool);
-	int exportBuffers(ImgUOutput *output, BufferPool *pool);
+	int importOutputBuffers(ImgUOutput *output, BufferPool *pool);
+	int exportOutputBuffers(ImgUOutput *output, BufferPool *pool);
 	void freeBuffers();
 
 	int start();
@@ -605,7 +606,7 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 	if (!pool)
 		return -ENOMEM;
 
-	ret = imgu->importBuffers(pool);
+	ret = imgu->importInputBuffers(pool);
 	if (ret)
 		goto error;
 
@@ -616,7 +617,7 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 	 */
 	bufferCount = pool->count();
 	imgu->stat_.pool->createBuffers(bufferCount);
-	ret = imgu->exportBuffers(&imgu->stat_, imgu->stat_.pool);
+	ret = imgu->exportOutputBuffers(&imgu->stat_, imgu->stat_.pool);
 	if (ret)
 		goto error;
 
@@ -625,7 +626,10 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 		IPU3Stream *stream = static_cast<IPU3Stream *>(s);
 		ImgUDevice::ImgUOutput *dev = stream->device_;
 
-		ret = imgu->exportBuffers(dev, &stream->bufferPool());
+		if (stream->memoryType() == InternalMemory)
+			ret = imgu->exportOutputBuffers(dev, &stream->bufferPool());
+		else
+			ret = imgu->importOutputBuffers(dev, &stream->bufferPool());
 		if (ret)
 			goto error;
 	}
@@ -637,8 +641,8 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 	if (!outStream->active_) {
 		bufferCount = vfStream->configuration().bufferCount;
 		outStream->device_->pool->createBuffers(bufferCount);
-		ret = imgu->exportBuffers(outStream->device_,
+		ret = imgu->exportOutputBuffers(outStream->device_,
-					  outStream->device_->pool);
+						outStream->device_->pool);
 		if (ret)
 			goto error;
 	}
@@ -646,8 +650,8 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera,
 	if (!vfStream->active_) {
 		bufferCount = outStream->configuration().bufferCount;
 		vfStream->device_->pool->createBuffers(bufferCount);
-		ret = imgu->exportBuffers(vfStream->device_,
+		ret = imgu->exportOutputBuffers(vfStream->device_,
-					  vfStream->device_->pool);
+						vfStream->device_->pool);
 		if (ret)
 			goto error;
 	}
@@ -1113,7 +1117,7 @@ int ImgUDevice::configureOutput(ImgUOutput *output,
  * \param[in] pool The buffer pool to import
  * \return 0 on success or a negative error code otherwise
  */
-int ImgUDevice::importBuffers(BufferPool *pool)
+int ImgUDevice::importInputBuffers(BufferPool *pool)
 {
 	int ret = input_->importBuffers(pool);
 	if (ret) {
@@ -1134,7 +1138,7 @@ int ImgUDevice::importBuffers(BufferPool *pool)
  *
  * \return 0 on success or a negative error code otherwise
  */
-int ImgUDevice::exportBuffers(ImgUOutput *output, BufferPool *pool)
+int ImgUDevice::exportOutputBuffers(ImgUOutput *output, BufferPool *pool)
 {
 	int ret = output->dev->exportBuffers(pool);
 	if (ret) {
@@ -1146,6 +1150,29 @@ int ImgUDevice::exportBuffers(ImgUOutput *output, BufferPool *pool)
 	return 0;
 }
 
+/**
+ * \brief Reserve buffers in \a output from the provided \a pool
+ * \param[in] output The ImgU output device
+ * \param[in] pool The buffer pool used to reserve buffers in \a output
+ *
+ * Reserve a number of buffers equal to the number of buffers in \a pool
+ * in the \a output device.
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int ImgUDevice::importOutputBuffers(ImgUOutput *output, BufferPool *pool)
+{
+	int ret = output->dev->importBuffers(pool);
+	if (ret) {
+		LOG(IPU3, Error)
+			<< "Failed to import buffer in " << output->name
+			<< " ImgU device";
+		return ret;
+	}
+
+	return 0;
+}
+
 /**
  * \brief Release buffers for all the ImgU video devices
  */

src/libcamera/pipeline/rkisp1/rkisp1.cpp

@@ -319,7 +319,11 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera,
 					   const std::set<Stream *> &streams)
 {
 	Stream *stream = *streams.begin();
-	return video_->exportBuffers(&stream->bufferPool());
+
+	if (stream->memoryType() == InternalMemory)
+		return video_->exportBuffers(&stream->bufferPool());
+	else
+		return video_->importBuffers(&stream->bufferPool());
 }
 
 int PipelineHandlerRkISP1::freeBuffers(Camera *camera,

src/libcamera/pipeline/uvcvideo.cpp

@@ -200,7 +200,10 @@ int PipelineHandlerUVC::allocateBuffers(Camera *camera,
 
 	LOG(UVC, Debug) << "Requesting " << cfg.bufferCount << " buffers";
 
-	return data->video_->exportBuffers(&stream->bufferPool());
+	if (stream->memoryType() == InternalMemory)
+		return data->video_->exportBuffers(&stream->bufferPool());
+	else
+		return data->video_->importBuffers(&stream->bufferPool());
 }
 
 int PipelineHandlerUVC::freeBuffers(Camera *camera,

src/libcamera/pipeline/vimc.cpp

@@ -202,7 +202,10 @@ int PipelineHandlerVimc::allocateBuffers(Camera *camera,
 
 	LOG(VIMC, Debug) << "Requesting " << cfg.bufferCount << " buffers";
 
-	return data->video_->exportBuffers(&stream->bufferPool());
+	if (stream->memoryType() == InternalMemory)
+		return data->video_->exportBuffers(&stream->bufferPool());
+	else
+		return data->video_->importBuffers(&stream->bufferPool());
 }
 
 int PipelineHandlerVimc::freeBuffers(Camera *camera,