3 files changed, 186 insertions, 0 deletions
diff --git a/src/android/camera_worker.cpp b/src/android/camera_worker.cpp
new file mode 100644
index 00000000..ff09b75e
--- /dev/null
+++ b/src/android/camera_worker.cpp
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * camera_worker.cpp - Process capture requests on behalf of the Camera HAL
+ */
+
+#include "camera_worker.h"
+
+#include <errno.h>
+#include <string.h>
+#include <sys/poll.h>
+
+#include "camera_device.h"
+
+using namespace libcamera;
+
+LOG_DECLARE_CATEGORY(HAL);
+
+/*
+ * \class CaptureRequest
+ * \brief Wrap a libcamera::Request associated with buffers and fences
+ *
+ * A CaptureRequest is constructed by the CameraDevice, filled with
+ * buffers and fences provided by the camera3 framework and then processed
+ * by the CameraWorker which queues it to the libcamera::Camera after handling
+ * fences.
+ */
+CaptureRequest::CaptureRequest(libcamera::Camera *camera, uint64_t cookie)
+	: camera_(camera)
+{
+	request_ = camera_->createRequest(cookie);
+}
+
+void CaptureRequest::addBuffer(Stream *stream, FrameBuffer *buffer, int fence)
+{
+	request_->addBuffer(stream, buffer);
+	acquireFences_.push_back(fence);
+}
+
+void CaptureRequest::queue()
+{
+	camera_->queueRequest(request_.get());
+}
+
+/*
+ * \class CameraWorker
+ * \brief Process a CaptureRequest on an internal thread
+ *
+ * The CameraWorker class wraps a Worker that runs on an internal thread
+ * and schedules processing of CaptureRequest through it.
+ */
+CameraWorker::CameraWorker()
+{
+	worker_.moveToThread(&thread_);
+}
+
+void CameraWorker::start()
+{
+	thread_.start();
+}
+
+void CameraWorker::stop()
+{
+	thread_.exit();
+	thread_.wait();
+}
+
+void CameraWorker::queueRequest(CaptureRequest *request)
+{
+	/* Async process the request on the worker which runs its own thread. */
+	worker_.invokeMethod(&Worker::processRequest, ConnectionTypeQueued,
+			     request);
+}
+
+/*
+ * \class CameraWorker::Worker
+ * \brief Process a CaptureRequest handling acquisition fences
+ */
+int CameraWorker::Worker::waitFence(int fence)
+{
+	/*
+	 * \todo Better characterize the timeout. Currently equal to the one
+	 * used by the Rockchip Camera HAL on ChromeOS.
+	 */
+	constexpr unsigned int timeoutMs = 300;
+	struct pollfd fds = { fence, POLLIN, 0 };
+
+	do {
+		int ret = poll(&fds, 1, timeoutMs);
+		if (ret == 0)
+			return -ETIME;
+
+		if (ret > 0) {
+			if (fds.revents & (POLLERR | POLLNVAL))
+				return -EINVAL;
+
+			return 0;
+		}
+	} while (errno == EINTR || errno == EAGAIN);
+
+	return -errno;
+}
+
+void CameraWorker::Worker::processRequest(CaptureRequest *request)
+{
+	/* Wait on all fences before queuing the Request. */
+	for (int fence : request->fences()) {
+		if (fence == -1)
+			continue;
+
+		int ret = waitFence(fence);
+		close(fence);
+		if (ret < 0) {
+			LOG(HAL, Error) << "Failed waiting for fence: "
+					<< fence << ": " << strerror(-ret);
+			return;
+		}
+	}
+
+	request->queue();
+}
diff --git a/src/android/camera_worker.h b/src/android/camera_worker.h
new file mode 100644
index 00000000..fff50217
--- /dev/null
+++ b/src/android/camera_worker.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * camera_worker.h - Process capture requests on behalf of the Camera HAL
+ */
+#ifndef __ANDROID_CAMERA_WORKER_H__
+#define __ANDROID_CAMERA_WORKER_H__
+
+#include <memory>
+
+#include <libcamera/buffer.h>
+#include <libcamera/camera.h>
+#include <libcamera/object.h>
+#include <libcamera/request.h>
+#include <libcamera/stream.h>
+
+#include "libcamera/internal/thread.h"
+
+class CameraDevice;
+
+class CaptureRequest
+{
+public:
+	CaptureRequest(libcamera::Camera *camera, uint64_t cookie);
+
+	const std::vector<int> &fences() const { return acquireFences_; }
+
+	void addBuffer(libcamera::Stream *stream,
+		       libcamera::FrameBuffer *buffer, int fence);
+	void queue();
+
+private:
+	libcamera::Camera *camera_;
+	std::vector<int> acquireFences_;
+	std::unique_ptr<libcamera::Request> request_;
+};
+
+class CameraWorker
+{
+public:
+	CameraWorker();
+
+	void start();
+	void stop();
+
+	void queueRequest(CaptureRequest *request);
+
+private:
+	class Worker : public libcamera::Object
+	{
+	public:
+		void processRequest(CaptureRequest *request);
+
+	private:
+		int waitFence(int fence);
+	};
+
+	Worker worker_;
+	libcamera::Thread thread_;
+};
+
+#endif /* __ANDROID_CAMERA_WORKER_H__ */
diff --git a/src/android/meson.build b/src/android/meson.build
index 802bb89a..b2b2293c 100644
--- a/src/android/meson.build
+++ b/src/android/meson.build
@@ -21,6 +21,7 @@ android_hal_sources = files([
     'camera_metadata.cpp',
     'camera_ops.cpp',
     'camera_stream.cpp',
+    'camera_worker.cpp',
     'jpeg/encoder_libjpeg.cpp',
     'jpeg/exif.cpp',
 ])