test: v4l2_device: Provide buffer sharing test

Obtain two V4L2Devices and use one to obtain a BufferPool.

Propagate the formats from the first to the second device and then commence
sending buffers between the two devices in a ping-pong fashion.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

test/v4l2_device/buffer_sharing.cpp

@@ -0,0 +1,187 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * libcamera V4L2 API tests
+ *
+ * Validate the function of exporting buffers from a V4L2Device and
+ * the ability to import them to another V4L2Device instance.
+ * Ensure that the Buffers can successfully be queued and dequeued
+ * between both devices.
+ */
+
+#include <iostream>
+
+#include <libcamera/buffer.h>
+#include <libcamera/camera_manager.h>
+#include <libcamera/event_dispatcher.h>
+#include <libcamera/timer.h>
+
+#include "v4l2_device_test.h"
+
+class BufferSharingTest : public V4L2DeviceTest
+{
+public:
+	BufferSharingTest()
+		: output_(nullptr), framesCaptured_(0), framesOutput_(0)
+	{
+	}
+
+private:
+	const unsigned int bufferCount = 4;
+
+	V4L2Device *output_;
+
+	unsigned int framesCaptured_;
+	unsigned int framesOutput_;
+
+protected:
+	int init()
+	{
+		int ret = V4L2DeviceTest::init();
+		if (ret)
+			return ret;
+
+		/* media_ already represents VIVID */
+		MediaEntity *entity = media_->getEntityByName("vivid-000-vid-out");
+		if (!entity)
+			return TestSkip;
+
+		output_ = new V4L2Device(entity);
+		if (!output_) {
+			std::cout << "Failed to create output device" << std::endl;
+			return TestFail;
+		}
+
+		ret = output_->open();
+		if (ret) {
+			std::cout << "Failed to open output device" << std::endl;
+			return TestFail;
+		}
+
+		V4L2DeviceFormat format = {};
+
+		ret = capture_->getFormat(&format);
+		if (ret) {
+			std::cout << "Failed to get capture format" << std::endl;
+			return TestFail;
+		}
+
+		ret = output_->setFormat(&format);
+		if (ret) {
+			std::cout << "Failed to set output format" << std::endl;
+			return TestFail;
+		}
+
+		pool_.createBuffers(bufferCount);
+
+		ret = capture_->exportBuffers(&pool_);
+		if (ret) {
+			std::cout << "Failed to export buffers" << std::endl;
+			return TestFail;
+		}
+
+		ret = output_->importBuffers(&pool_);
+		if (ret) {
+			std::cout << "Failed to import buffers" << std::endl;
+			return TestFail;
+		}
+
+		return 0;
+	}
+
+	void captureBufferReady(Buffer *buffer)
+	{
+		std::cout << "Received capture buffer: " << buffer->index()
+			  << " sequence " << buffer->sequence() << std::endl;
+
+		output_->queueBuffer(buffer);
+		framesCaptured_++;
+	}
+
+	void outputBufferReady(Buffer *buffer)
+	{
+		std::cout << "Received output buffer: " << buffer->index()
+			  << " sequence " << buffer->sequence() << std::endl;
+
+		capture_->queueBuffer(buffer);
+		framesOutput_++;
+	}
+
+	int run()
+	{
+		EventDispatcher *dispatcher = CameraManager::instance()->eventDispatcher();
+		Timer timeout;
+		int ret;
+
+		capture_->bufferReady.connect(this, &BufferSharingTest::captureBufferReady);
+		output_->bufferReady.connect(this, &BufferSharingTest::outputBufferReady);
+
+		/* Queue all the buffers to the capture device. */
+		for (Buffer &buffer : pool_.buffers()) {
+			if (capture_->queueBuffer(&buffer))
+				return TestFail;
+		}
+
+		ret = capture_->streamOn();
+		if (ret) {
+			std::cout << "Failed to start streaming on the capture device" << std::endl;
+			return TestFail;
+		}
+
+		ret = output_->streamOn();
+		if (ret) {
+			std::cout << "Failed to start streaming on the output device" << std::endl;
+			return TestFail;
+		}
+
+		timeout.start(10000);
+		while (timeout.isRunning()) {
+			dispatcher->processEvents();
+			if (framesCaptured_ > 30 && framesOutput_ > 30)
+				break;
+		}
+
+		if ((framesCaptured_ < 1) || (framesOutput_ < 1)) {
+			std::cout << "Failed to process any frames within timeout." << std::endl;
+			return TestFail;
+		}
+
+		if ((framesCaptured_ < 30) || (framesOutput_ < 30)) {
+			std::cout << "Failed to process 30 frames within timeout." << std::endl;
+			return TestFail;
+		}
+
+		ret = capture_->streamOff();
+		if (ret) {
+			std::cout << "Failed to stop streaming on the capture device" << std::endl;
+			return TestFail;
+		}
+
+		ret = output_->streamOff();
+		if (ret) {
+			std::cout << "Failed to stop streaming on the output device" << std::endl;
+			return TestFail;
+		}
+
+		return TestPass;
+	}
+
+	void cleanup()
+	{
+		std::cout
+			<< "Captured " << framesCaptured_ << " frames and "
+			<< "output " << framesOutput_ << " frames"
+			<< std::endl;
+
+		output_->streamOff();
+		output_->releaseBuffers();
+		output_->close();
+
+		delete output_;
+
+		V4L2DeviceTest::cleanup();
+	}
+};
+
+TEST_REGISTER(BufferSharingTest);

test/v4l2_device/meson.build

@@ -5,6 +5,7 @@ v4l2_device_tests = [
   [ 'request_buffers',    'request_buffers.cpp' ],
   [ 'stream_on_off',      'stream_on_off.cpp' ],
   [ 'capture_async',      'capture_async.cpp' ],
+  [ 'buffer_sharing',     'buffer_sharing.cpp' ],
 ]
 
 foreach t : v4l2_device_tests