libcamera: ipu3: Implement memory handling

Implement buffer allocation and release in IPU3 pipeline handlers.

As the pipeline handler currently supports a single stream, provide two
internal buffer pools for 'viewfinder' and 'stat' video devices, and
export the 'output' video device buffers to the stream's pool. This
works around the fact that the ImgU requires buffers to be queued on all
its outputs, even when they are not in use.

Share buffers between the CIO2 output and the ImgU input video devices,
as the output of the former should immediately be provided to the
latter for further processing.

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

1 files changed, 140 insertions, 14 deletions

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 030135f4..34bfc2a0 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -40,6 +40,7 @@ public:
 		V4L2Device *dev;
 		unsigned int pad;
 		std::string name;
+		BufferPool *pool;
 	};
 
 	ImgUDevice()
@@ -65,6 +66,10 @@ public:
 	int configureOutput(ImgUOutput *output,
 			    const StreamConfiguration &config);
 
+	int importBuffers(BufferPool *pool);
+	int exportBuffers(ImgUOutput *output, BufferPool *pool);
+	void freeBuffers();
+
 	unsigned int index_;
 	std::string name_;
 	MediaDevice *media_;
@@ -75,11 +80,16 @@ public:
 	ImgUOutput viewfinder_;
 	ImgUOutput stat_;
 	/* \todo Add param video device for 3A tuning */
+
+	BufferPool vfPool_;
+	BufferPool statPool_;
 };
 
 class CIO2Device
 {
 public:
+	static constexpr unsigned int CIO2_BUFFER_COUNT = 4;
+
 	CIO2Device()
 		: output_(nullptr), csi2_(nullptr), sensor_(nullptr)
 	{
@@ -96,6 +106,9 @@ public:
 	int configure(const StreamConfiguration &config,
 		      V4L2DeviceFormat *outputFormat);
 
+	BufferPool *exportBuffers();
+	void freeBuffers();
+
 	static int mediaBusToFormat(unsigned int code);
 
 	V4L2Device *output_;
@@ -105,6 +118,8 @@ public:
 	/* Maximum sizes and the mbus code used to produce them. */
 	unsigned int mbusCode_;
 	Size maxSize_;
+
+	BufferPool pool_;
 };
 
 class PipelineHandlerIPU3 : public PipelineHandler
@@ -268,18 +283,41 @@ int PipelineHandlerIPU3::configureStreams(Camera *camera,
 
 int PipelineHandlerIPU3::allocateBuffers(Camera *camera, Stream *stream)
 {
-	const StreamConfiguration &cfg = stream->configuration();
 	IPU3CameraData *data = cameraData(camera);
-	V4L2Device *cio2 = data->cio2_.output_;
+	CIO2Device *cio2 = &data->cio2_;
+	ImgUDevice *imgu = data->imgu_;
+	int ret;
 
-	if (!cfg.bufferCount)
-		return -EINVAL;
+	/* Share buffers between CIO2 output and ImgU input. */
+	BufferPool *pool = cio2->exportBuffers();
+	if (!pool)
+		return -ENOMEM;
 
-	int ret = cio2->exportBuffers(&stream->bufferPool());
-	if (ret) {
-		LOG(IPU3, Error) << "Failed to request memory";
+	ret = imgu->importBuffers(pool);
+	if (ret)
+		return ret;
+
+	/* Export ImgU output buffers to the stream's pool. */
+	ret = imgu->exportBuffers(&imgu->output_, &stream->bufferPool());
+	if (ret)
+		return ret;
+
+	/*
+	 * Reserve memory in viewfinder and stat output devices. Use the
+	 * same number of buffers as the ones requested for the output
+	 * stream.
+	 */
+	unsigned int bufferCount = stream->bufferPool().count();
+
+	imgu->viewfinder_.pool->createBuffers(bufferCount);
+	ret = imgu->exportBuffers(&imgu->viewfinder_, imgu->viewfinder_.pool);
+	if (ret)
+		return ret;
+
+	imgu->stat_.pool->createBuffers(bufferCount);
+	ret = imgu->exportBuffers(&imgu->stat_, imgu->stat_.pool);
+	if (ret)
 		return ret;
-	}
 
 	return 0;
 }
@@ -287,13 +325,9 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera, Stream *stream)
 int PipelineHandlerIPU3::freeBuffers(Camera *camera, Stream *stream)
 {
 	IPU3CameraData *data = cameraData(camera);
-	V4L2Device *cio2 = data->cio2_.output_;
 
-	int ret = cio2->releaseBuffers();
-	if (ret) {
-		LOG(IPU3, Error) << "Failed to release memory";
-		return ret;
-	}
+	data->cio2_.freeBuffers();
+	data->imgu_->freeBuffers();
 
 	return 0;
 }
@@ -553,6 +587,7 @@ int ImgUDevice::init(MediaDevice *media, unsigned int index)
 
 	viewfinder_.pad = PAD_VF;
 	viewfinder_.name = "viewfinder";
+	viewfinder_.pool = &vfPool_;
 
 	stat_.dev = V4L2Device::fromEntityName(media, name_ + " 3a stat");
 	ret = stat_.dev->open();
@@ -561,6 +596,7 @@ int ImgUDevice::init(MediaDevice *media, unsigned int index)
 
 	stat_.pad = PAD_STAT;
 	stat_.name = "stat";
+	stat_.pool = &statPool_;
 
 	return 0;
 }
@@ -665,6 +701,69 @@ int ImgUDevice::configureOutput(ImgUOutput *output,
 	return 0;
 }
 
+/**
+ * \brief Import buffers from \a pool into the ImgU input
+ * \param[in] pool The buffer pool to import
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int ImgUDevice::importBuffers(BufferPool *pool)
+{
+	int ret = input_->importBuffers(pool);
+	if (ret) {
+		LOG(IPU3, Error) << "Failed to import ImgU input buffers";
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * \brief Export buffers from \a output to the provided \a pool
+ * \param[in] output The ImgU output device
+ * \param[in] pool The buffer pool where to export buffers
+ *
+ * Export memory buffers reserved in the video device memory associated with
+ * \a output id to the buffer pool provided as argument.
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int ImgUDevice::exportBuffers(ImgUOutput *output, BufferPool *pool)
+{
+	int ret = output->dev->exportBuffers(pool);
+	if (ret) {
+		LOG(IPU3, Error) << "Failed to export ImgU "
+				 << output->name << " buffers";
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * \brief Release buffers for all the ImgU video devices
+ */
+void ImgUDevice::freeBuffers()
+{
+	int ret;
+
+	ret = output_.dev->releaseBuffers();
+	if (ret)
+		LOG(IPU3, Error) << "Failed to release ImgU output buffers";
+
+	ret = stat_.dev->releaseBuffers();
+	if (ret)
+		LOG(IPU3, Error) << "Failed to release ImgU stat buffers";
+
+	ret = viewfinder_.dev->releaseBuffers();
+	if (ret)
+		LOG(IPU3, Error) << "Failed to release ImgU viewfinder buffers";
+
+	ret = input_->releaseBuffers();
+	if (ret)
+		LOG(IPU3, Error) << "Failed to release ImgU input buffers";
+}
+
 /*------------------------------------------------------------------------------
  * CIO2 Device
  */
@@ -831,6 +930,33 @@ int CIO2Device::configure(const StreamConfiguration &config,
 	return 0;
 }
 
+/**
+ * \brief Allocate CIO2 memory buffers and export them in a BufferPool
+ *
+ * Allocate memory buffers in the CIO2 video device and export them to
+ * a buffer pool that can be imported by another device.
+ *
+ * \return The buffer pool with export buffers on success or nullptr otherwise
+ */
+BufferPool *CIO2Device::exportBuffers()
+{
+	pool_.createBuffers(CIO2_BUFFER_COUNT);
+
+	int ret = output_->exportBuffers(&pool_);
+	if (ret) {
+		LOG(IPU3, Error) << "Failed to export CIO2 buffers";
+		return nullptr;
+	}
+
+	return &pool_;
+}
+
+void CIO2Device::freeBuffers()
+{
+	if (output_->releaseBuffers())
+		LOG(IPU3, Error) << "Failed to release CIO2 buffers";
+}
+
 int CIO2Device::mediaBusToFormat(unsigned int code)
 {
 	switch (code) {