libcamera: Declare generic converter interface

Declare a converter Abstract Base Class intended to provide generic
interfaces to hardware offering size and format conversion services on
streams. This is mainly based on the public interfaces of the current
converter class implementation found in the simple pipeline handler.

The main change is the introduction of loadConfiguration() function
which can be used by the concrete implementation to load hardware
specific runtime parameters defined by the application.

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>

2 files changed, 109 insertions, 0 deletions

diff --git a/include/libcamera/internal/converter.h b/include/libcamera/internal/converter.h
new file mode 100644
index 00000000..834ec5ab
--- /dev/null
+++ b/include/libcamera/internal/converter.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Laurent Pinchart
+ * Copyright 2022 NXP
+ *
+ * converter.h - Generic format converter interface
+ */
+
+#pragma once
+
+#include <functional>
+#include <initializer_list>
+#include <map>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <libcamera/base/class.h>
+#include <libcamera/base/signal.h>
+
+#include <libcamera/geometry.h>
+
+namespace libcamera {
+
+class FrameBuffer;
+class MediaDevice;
+class PixelFormat;
+struct StreamConfiguration;
+
+class Converter
+{
+public:
+	Converter(MediaDevice *media);
+	virtual ~Converter();
+
+	virtual int loadConfiguration(const std::string &filename) = 0;
+
+	virtual bool isValid() const = 0;
+
+	virtual std::vector<PixelFormat> formats(PixelFormat input) = 0;
+	virtual SizeRange sizes(const Size &input) = 0;
+
+	virtual std::tuple<unsigned int, unsigned int>
+	strideAndFrameSize(const PixelFormat &pixelFormat, const Size &size) = 0;
+
+	virtual int configure(const StreamConfiguration &inputCfg,
+			      const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfgs) = 0;
+	virtual int exportBuffers(unsigned int output, unsigned int count,
+				  std::vector<std::unique_ptr<FrameBuffer>> *buffers) = 0;
+
+	virtual int start() = 0;
+	virtual void stop() = 0;
+
+	virtual int queueBuffers(FrameBuffer *input,
+				 const std::map<unsigned int, FrameBuffer *> &outputs) = 0;
+
+	Signal<FrameBuffer *> inputBufferReady;
+	Signal<FrameBuffer *> outputBufferReady;
+
+	const std::string &deviceNode() const { return deviceNode_; }
+
+private:
+	std::string deviceNode_;
+};
+
+class ConverterFactoryBase
+{
+public:
+	ConverterFactoryBase(const std::string name, std::initializer_list<std::string> compatibles);
+	virtual ~ConverterFactoryBase() = default;
+
+	const std::vector<std::string> &compatibles() const { return compatibles_; }
+
+	static std::unique_ptr<Converter> create(MediaDevice *media);
+	static std::vector<ConverterFactoryBase *> &factories();
+	static std::vector<std::string> names();
+
+private:
+	LIBCAMERA_DISABLE_COPY_AND_MOVE(ConverterFactoryBase)
+
+	static void registerType(ConverterFactoryBase *factory);
+
+	virtual std::unique_ptr<Converter> createInstance(MediaDevice *media) const = 0;
+
+	std::string name_;
+	std::vector<std::string> compatibles_;
+};
+
+template<typename _Converter>
+class ConverterFactory : public ConverterFactoryBase
+{
+public:
+	ConverterFactory(const char *name, std::initializer_list<std::string> compatibles)
+		: ConverterFactoryBase(name, compatibles)
+	{
+	}
+
+	std::unique_ptr<Converter> createInstance(MediaDevice *media) const override
+	{
+		return std::make_unique<_Converter>(media);
+	}
+};
+
+#define REGISTER_CONVERTER(name, converter, compatibles) \
+	static ConverterFactory<converter> global_##converter##Factory(name, compatibles);
+
+} /* namespace libcamera */
diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
index f8be86e0..341af8a2 100644
--- a/include/libcamera/internal/meson.build
+++ b/include/libcamera/internal/meson.build
@@ -19,6 +19,7 @@ libcamera_internal_headers = files([
     'camera_sensor_properties.h',
     'control_serializer.h',
     'control_validator.h',
+    'converter.h',
     'delayed_controls.h',
     'device_enumerator.h',
     'device_enumerator_sysfs.h',