libcamera: pipeline: simple: converter: Use generic converter interface

Move the simple converter implementation to a generic V4L2 M2M class
derived from the converter interface. This latter could be used by
other pipeline implementations and as base class for customized V4L2 M2M
converters.

Signed-off-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/internal/converter/converter_v4l2_m2m.h

@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Laurent Pinchart
+ * Copyright 2022 NXP
+ *
+ * converter_v4l2_m2m.h - V4l2 M2M Format converter interface
+ */
+
+#pragma once
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/signal.h>
+
+#include <libcamera/pixel_format.h>
+
+#include "libcamera/internal/converter.h"
+
+namespace libcamera {
+
+class FrameBuffer;
+class MediaDevice;
+class Size;
+class SizeRange;
+struct StreamConfiguration;
+class V4L2M2MDevice;
+
+class V4L2M2MConverter : public Converter
+{
+public:
+	V4L2M2MConverter(MediaDevice *media);
+
+	int loadConfiguration([[maybe_unused]] const std::string &filename) { return 0; }
+	bool isValid() const { return m2m_ != nullptr; }
+
+	std::vector<PixelFormat> formats(PixelFormat input);
+	SizeRange sizes(const Size &input);
+
+	std::tuple<unsigned int, unsigned int>
+	strideAndFrameSize(const PixelFormat &pixelFormat, const Size &size);
+
+	int configure(const StreamConfiguration &inputCfg,
+		      const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfg);
+	int exportBuffers(unsigned int ouput, unsigned int count,
+			  std::vector<std::unique_ptr<FrameBuffer>> *buffers);
+
+	int start();
+	void stop();
+
+	int queueBuffers(FrameBuffer *input,
+			 const std::map<unsigned int, FrameBuffer *> &outputs);
+
+private:
+	class Stream : protected Loggable
+	{
+	public:
+		Stream(V4L2M2MConverter *converter, unsigned int index);
+
+		bool isValid() const { return m2m_ != nullptr; }
+
+		int configure(const StreamConfiguration &inputCfg,
+			      const StreamConfiguration &outputCfg);
+		int exportBuffers(unsigned int count,
+				  std::vector<std::unique_ptr<FrameBuffer>> *buffers);
+
+		int start();
+		void stop();
+
+		int queueBuffers(FrameBuffer *input, FrameBuffer *output);
+
+	protected:
+		std::string logPrefix() const override;
+
+	private:
+		void captureBufferReady(FrameBuffer *buffer);
+		void outputBufferReady(FrameBuffer *buffer);
+
+		V4L2M2MConverter *converter_;
+		unsigned int index_;
+		std::unique_ptr<V4L2M2MDevice> m2m_;
+
+		unsigned int inputBufferCount_;
+		unsigned int outputBufferCount_;
+	};
+
+	std::unique_ptr<V4L2M2MDevice> m2m_;
+
+	std::vector<Stream> streams_;
+	std::map<FrameBuffer *, unsigned int> queue_;
+};
+
+} /* namespace libcamera */

include/libcamera/internal/converter/meson.build

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: CC0-1.0
+
+libcamera_internal_headers += files([
+    'converter_v4l2_m2m.h',
+])

include/libcamera/internal/meson.build

@@ -45,3 +45,5 @@ libcamera_internal_headers = files([
     'v4l2_videodevice.h',
     'yaml_parser.h',
 ])
+
+subdir('converter')