libcamera: pipeline: simple: Add simple format converter

The simple format converter supports V4L2 M2M devices that convert pixel
formats.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

3 files changed, 278 insertions, 0 deletions

diff --git a/src/libcamera/pipeline/simple/converter.cpp b/src/libcamera/pipeline/simple/converter.cpp
new file mode 100644
index 00000000..6d88776d
--- /dev/null
+++ b/src/libcamera/pipeline/simple/converter.cpp
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Laurent Pinchart
+ *
+ * converter.cpp - Format converter for simple pipeline handler
+ */
+
+#include "converter.h"
+
+#include <algorithm>
+
+#include <libcamera/buffer.h>
+#include <libcamera/geometry.h>
+#include <libcamera/signal.h>
+
+#include "log.h"
+#include "media_device.h"
+#include "v4l2_videodevice.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(SimplePipeline);
+
+SimpleConverter::SimpleConverter(MediaDevice *media)
+	: m2m_(nullptr)
+{
+	/*
+	 * Locate the video node. There's no need to validate the pipeline
+	 * further, the caller guarantees that this is a V4L2 mem2mem device.
+	 */
+	const std::vector<MediaEntity *> &entities = media->entities();
+	auto it = std::find_if(entities.begin(), entities.end(),
+			       [](MediaEntity *entity) {
+				       return entity->function() == MEDIA_ENT_F_IO_V4L;
+			       });
+	if (it == entities.end())
+		return;
+
+	m2m_ = new V4L2M2MDevice((*it)->deviceNode());
+
+	m2m_->output()->bufferReady.connect(this, &SimpleConverter::outputBufferReady);
+	m2m_->capture()->bufferReady.connect(this, &SimpleConverter::captureBufferReady);
+}
+
+SimpleConverter::~SimpleConverter()
+{
+	delete m2m_;
+}
+
+int SimpleConverter::open()
+{
+	if (!m2m_)
+		return -ENODEV;
+
+	return m2m_->open();
+}
+
+void SimpleConverter::close()
+{
+	if (m2m_)
+		m2m_->close();
+}
+
+std::vector<PixelFormat> SimpleConverter::formats(PixelFormat input)
+{
+	if (!m2m_)
+		return {};
+
+	/*
+	 * Set the format on the input side (V4L2 output) of the converter to
+	 * enumerate the conversion capabilities on its output (V4L2 capture).
+	 */
+	V4L2DeviceFormat format;
+	format.fourcc = m2m_->output()->toV4L2PixelFormat(input);
+	format.size = { 1, 1 };
+
+	int ret = m2m_->output()->setFormat(&format);
+	if (ret < 0) {
+		LOG(SimplePipeline, Error)
+			<< "Failed to set format: " << strerror(-ret);
+		return {};
+	}
+
+	std::vector<PixelFormat> pixelFormats;
+
+	for (const auto &format : m2m_->capture()->formats()) {
+		PixelFormat pixelFormat = format.first.toPixelFormat();
+		if (pixelFormat)
+			pixelFormats.push_back(pixelFormat);
+	}
+
+	return pixelFormats;
+}
+
+int SimpleConverter::configure(PixelFormat inputFormat,
+			       PixelFormat outputFormat, const Size &size)
+{
+	V4L2DeviceFormat format;
+	int ret;
+
+	V4L2PixelFormat videoFormat = m2m_->output()->toV4L2PixelFormat(inputFormat);
+	format.fourcc = videoFormat;
+	format.size = size;
+
+	ret = m2m_->output()->setFormat(&format);
+	if (ret < 0) {
+		LOG(SimplePipeline, Error)
+			<< "Failed to set input format: " << strerror(-ret);
+		return ret;
+	}
+
+	if (format.fourcc != videoFormat || format.size != size) {
+		LOG(SimplePipeline, Error)
+			<< "Input format not supported";
+		return -EINVAL;
+	}
+
+	/*
+	 * Set the pixel format on the output, the size is identical to the
+	 * input as we don't support scaling.
+	 */
+	videoFormat = m2m_->capture()->toV4L2PixelFormat(outputFormat);
+	format.fourcc = videoFormat;
+
+	ret = m2m_->capture()->setFormat(&format);
+	if (ret < 0) {
+		LOG(SimplePipeline, Error)
+			<< "Failed to set output format: " << strerror(-ret);
+		return ret;
+	}
+
+	if (format.fourcc != videoFormat || format.size != size) {
+		LOG(SimplePipeline, Error)
+			<< "Output format not supported";
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int SimpleConverter::exportBuffers(unsigned int count,
+				   std::vector<std::unique_ptr<FrameBuffer>> *buffers)
+{
+	return m2m_->capture()->exportBuffers(count, buffers);
+}
+
+int SimpleConverter::start(unsigned int count)
+{
+	int ret = m2m_->output()->importBuffers(count);
+	if (ret < 0)
+		return ret;
+
+	ret = m2m_->capture()->importBuffers(count);
+	if (ret < 0) {
+		stop();
+		return ret;
+	}
+
+	ret = m2m_->output()->streamOn();
+	if (ret < 0) {
+		stop();
+		return ret;
+	}
+
+	ret = m2m_->capture()->streamOn();
+	if (ret < 0) {
+		stop();
+		return ret;
+	}
+
+	return 0;
+}
+
+void SimpleConverter::stop()
+{
+	m2m_->capture()->streamOff();
+	m2m_->output()->streamOff();
+	m2m_->capture()->releaseBuffers();
+	m2m_->output()->releaseBuffers();
+}
+
+int SimpleConverter::queueBuffers(FrameBuffer *input, FrameBuffer *output)
+{
+	int ret = m2m_->output()->queueBuffer(input);
+	if (ret < 0)
+		return ret;
+
+	ret = m2m_->capture()->queueBuffer(output);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+void SimpleConverter::captureBufferReady(FrameBuffer *buffer)
+{
+	if (!outputDoneQueue_.empty()) {
+		FrameBuffer *other = outputDoneQueue_.front();
+		outputDoneQueue_.pop();
+		bufferReady.emit(other, buffer);
+	} else {
+		captureDoneQueue_.push(buffer);
+	}
+}
+
+void SimpleConverter::outputBufferReady(FrameBuffer *buffer)
+{
+	if (!captureDoneQueue_.empty()) {
+		FrameBuffer *other = captureDoneQueue_.front();
+		captureDoneQueue_.pop();
+		bufferReady.emit(buffer, other);
+	} else {
+		outputDoneQueue_.push(buffer);
+	}
+}
+
+} /* namespace libcamera */
diff --git a/src/libcamera/pipeline/simple/converter.h b/src/libcamera/pipeline/simple/converter.h
new file mode 100644
index 00000000..a33071fa
--- /dev/null
+++ b/src/libcamera/pipeline/simple/converter.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Laurent Pinchart
+ *
+ * converter.h - Format converter for simple pipeline handler
+ */
+
+#ifndef __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__
+#define __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__
+
+#include <memory>
+#include <queue>
+#include <vector>
+
+#include <libcamera/pixelformats.h>
+#include <libcamera/signal.h>
+
+namespace libcamera {
+
+class FrameBuffer;
+class MediaDevice;
+struct Size;
+class V4L2M2MDevice;
+
+class SimpleConverter
+{
+public:
+	SimpleConverter(MediaDevice *media);
+	~SimpleConverter();
+
+	int open();
+	void close();
+
+	std::vector<PixelFormat> formats(PixelFormat input);
+
+	int configure(PixelFormat inputFormat, PixelFormat outputFormat,
+		      const Size &size);
+	int exportBuffers(unsigned int count,
+			  std::vector<std::unique_ptr<FrameBuffer>> *buffers);
+
+	int start(unsigned int count);
+	void stop();
+
+	int queueBuffers(FrameBuffer *input, FrameBuffer *output);
+
+	Signal<FrameBuffer *, FrameBuffer *> bufferReady;
+
+private:
+	void captureBufferReady(FrameBuffer *buffer);
+	void outputBufferReady(FrameBuffer *buffer);
+
+	V4L2M2MDevice *m2m_;
+
+	std::queue<FrameBuffer *> captureDoneQueue_;
+	std::queue<FrameBuffer *> outputDoneQueue_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__ */
diff --git a/src/libcamera/pipeline/simple/meson.build b/src/libcamera/pipeline/simple/meson.build
index 4945a3e1..8372f24e 100644
--- a/src/libcamera/pipeline/simple/meson.build
+++ b/src/libcamera/pipeline/simple/meson.build
@@ -1,3 +1,4 @@
 libcamera_sources += files([
+    'converter.cpp',
     'simple.cpp',
 ])