[libcamera-devel] [PATCH 05/10] libcamera: ipu3: Implement buffer allocation

[Jacopo Mondi]

Implement buffer allocation in IPU3 pipeline handlers.
As the pipeline handler supports a single stream, preprare two buffer
pools for 'viewfinder' and 'stat' video devices, and export the 'output'
video device buffers to the Stream's pool.

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.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 47 ++++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 6 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 1e89e57f628b..c7b7973952a0 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -47,6 +47,9 @@ struct ImguDevice {
 	V4L2Device *viewfinder;
 	V4L2Device *stat;
 	/* TODO: add param video device for 3A tuning */
+
+	BufferPool vfPool;
+	BufferPool statPool;
 };
 
 struct Cio2Device {
@@ -63,6 +66,8 @@ struct Cio2Device {
 	V4L2Device *output;
 	V4L2Subdevice *csi2;
 	V4L2Subdevice *sensor;
+
+	BufferPool pool;
 };
 
 class IPU3CameraData : public CameraData
@@ -319,18 +324,48 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera, Stream *stream)
 {
 	const StreamConfiguration &cfg = stream->configuration();
 	IPU3CameraData *data = cameraData(camera);
+	V4L2Device *viewfinder = data->imgu->viewfinder;
+	V4L2Device *output = data->imgu->output;
+	V4L2Device *input = data->imgu->input;
 	V4L2Device *cio2 = data->cio2.output;
+	V4L2Device *stat = data->imgu->stat;
+	int ret;
 
-	if (!cfg.bufferCount)
+	if (!cfg.bufferCount) {
+		LOG(IPU3, Error)
+			<< "Invalid number of buffers: "<< cfg.bufferCount;
 		return -EINVAL;
-
-	int ret = cio2->exportBuffers(&stream->bufferPool());
-	if (ret) {
-		LOG(IPU3, Error) << "Failed to request memory";
-		return ret;
 	}
 
+	/* Share buffers between CIO2 output and ImgU input. */
+	data->cio2.pool.createBuffers(IPU3_BUF_NUM);
+	ret = cio2->exportBuffers(&data->cio2.pool);
+	if (ret)
+		goto error_reserve_memory;
+	input->importBuffers(&data->cio2.pool);
+
+	/* Prepare the buffer pools for viewfinder and stat. */
+	data->imgu->vfPool.createBuffers(IPU3_BUF_NUM);
+	ret = viewfinder->exportBuffers(&data->imgu->vfPool);
+	if (ret)
+		goto error_reserve_memory;
+
+	data->imgu->statPool.createBuffers(IPU3_BUF_NUM);
+	ret = stat->exportBuffers(&data->imgu->statPool);
+	if (ret)
+		goto error_reserve_memory;
+
+	/* Export ImgU output buffers to the stream's pool. */
+	ret = output->exportBuffers(&stream->bufferPool());
+	if (ret)
+		goto error_reserve_memory;
+
 	return 0;
+
+error_reserve_memory:
+	LOG(IPU3, Error) << "Failed to reserve memory";
+
+	return ret;
 }
 
 int PipelineHandlerIPU3::freeBuffers(Camera *camera, Stream *stream)
-- 
2.20.1