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2022-03-03android: camera_request: Lifetime of a Camera3RequestDescriptorUmang Jain
This commit provides a sketch regarding Camera3RequestDescriptor which aids tracking each capture reuqest placed by the android framework to libcamera HAL. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2022-03-03android: Document the structures and functions for post-processingUmang Jain
Specifically document: - CameraDevice::sendCaptureResults() - CameraDevice::completeDescriptor() - CameraDevice::streamProcessingComplete() - CameraStream::PostProcessorWorker class - Camera3RequestDescriptor::StreamBuffer structure Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2021-12-11android: Remove CameraWorkerJacopo Mondi
The CameraWorker class purpose was to handle acquire fences for incoming capture requests directed to libcamera. Now that fences are handled by the core library, it is not required to handle them in the HAL and the CameraWorker and CaptureRequest classes can be dropped. Update the core in CameraDevice class accordingly to queue Requests directly to the libcamera::Camera and set the release_fence to the value of the FrameBuffer::fence() for streams of type ::Direct. While at it make CameraRequest::StreamBuffer::fence a UniqueFD to ease the management of the fences file descriptor values. Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-11-08android: Camera3RequestDescriptor: Provide a constructor for StreamBufferUmang Jain
Provide a constructor for StreamBuffer and use that while populating Camera3RequestDescriptor::buffers_ vector. Also provide the default move-constructor (required as StreamBuffer is stored in a vector in Camera3RequestDescriptor) and destructor for the StreamBuffer struct. Also declare a default move assignment operator and disable the copy constructor and move operator explicitly with LIBCAMERA_DISABLE_COPY(). While at it, initialize pointers members in the StreamBuffer struct to nullptr, with StreamBuffer::status set to Status::Success by default. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2021-10-26android: post_processor: Consolidate contextual informationUmang Jain
Save and provide the context for post-processor of a camera stream via Camera3RequestDescriptor::StreamBuffer. We extend the structure to include source and destination buffers for the post processor, along with CameraStream::Type::Internal buffer pointer (if any). In addition to that, a back pointer to Camera3RequestDescriptor is convenient to get access to overall descriptor (status, metadata settings etc.). Also, migrate CameraStream::process() and PostProcessor::process() signature to use Camera3RequestDescriptor::StreamBuffer only. This will be helpful when we move to async post-processing in subsequent commits. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-10-26android: camera_device: Refactor descriptor status and sendCaptureResults()Umang Jain
Currently, we use Camera3RequestDescriptor::Status to determine: - When the descriptor has been completely processed by HAL - Whether any errors were encountered, during its processing Both of these are essential to know whether the descriptor is eligible to call process_capture_results() through sendCaptureResults(). When a status(Success/Error) is set on the descriptor, it is ready to be sent back via sendCaptureResults(). However, this might lead to undesired results especially when sendCaptureResults() runs in a different thread (for e.g. stream's post-processor async completion slot). This patch decouples the descriptor status (Success/Error) from the descriptor's completion status (pending or complete). The advantage of this is we can set the completion status when the descriptor has been processed fully by the layer and we can set the error status on the descriptor wherever an error is encountered, throughout the lifetime of the descriptor in the HAL layer. While at it, introduce a wrapper completeDescriptor() around sendCaptureResults(). completeDescriptor() as the name suggests will mark the descriptor as complete, so it is ready to be sent back. The locking mechanism is moved from sendCaptureResults() to this wrapper since the intention is to use completeDescriptor() in place of existing sendCaptureResults() calls. Also make sure the sequence of abortRequest() call happens in the same order at all places i.e. after its added to the descriptors_ queue. Fix one of the abortRequest() call accordingly. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-10-19android: camera_request: Don't embed full camera3_stream_buffer_tLaurent Pinchart
The camera3_stream_buffer_t structure is meant to communicate between the camera service and the HAL. They are short-live structures that don't outlive the .process_capture_request() operation (when queuing requests) or the .process_capture_result() callback. We currently store copies of the camera3_stream_buffer_t passed to .process_capture_request() in Camera3RequestDescriptor::StreamBuffer to store the structure members that the HAL need, and reuse them when calling the .process_capture_result() callback. This is conceptually not right, as the camera3_stream_buffer_t pass to the callback are not the same objects as the ones received in .process_capture_request(). Store individual fields of the camera3_stream_buffer_t in StreamBuffer instead of copying the whole structure. This gives the HAL full control of how data is stored, and properly decouples request queueing from result reporting. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2021-10-19android: camera_device: Create struct to track per stream bufferUmang Jain
The Camera3RequestDescriptor structure stores, for each stream, the camera3_stream_buffer_t and the libcamera FrameBuffer in two separate vectors. This complicates buffer handling, as the code needs to keep both vectors in sync. Create a new structure to group all data about per-stream buffers to simplify this. As a side effect, we need to create a local vector of camera3_stream_buffer_t in CameraDevice::sendCaptureResults() as the camera3_stream_buffer_t instances stored in the new structure in Camera3RequestDescriptor are not contiguous anymore. This is a small price to pay for easier handling of buffers, and will be refactored in subsequent commits anyway. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-10-19android: camera_request: Turn struct into a classLaurent Pinchart
The Camera3RequestDescriptor structure is growing into an object with member functions. Turn it into a class, uninline the destructor to reduce code size, explicitly disable copy as requests are not copyable, and delete the default constructor to force all instances to be fully constructed. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
2021-10-19camera_device: Remove private scope of Camera3RequestDescriptorUmang Jain
Camera3RequestDescriptor is a utility structure that groups information about a capture request. It can be and will be extended to preserve the context of a capture overall. Since the context of a capture needs to be shared among other classes (for e.g. CameraStream) having a private definition of the struct in CameraDevice class doesn't help. Hence, de-scope the structure so that it can be shared with other components (through references or pointers). Splitting the structure to a separate file will help avoiding circular dependencies when using it through the HAL implementation. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_camera_proxy.cpp - Proxy to V4L2 compatibility camera
 */

#include "v4l2_camera_proxy.h"

#include <algorithm>
#include <array>
#include <errno.h>
#include <numeric>
#include <set>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>

#include <linux/videodev2.h>

#include <libcamera/base/log.h>
#include <libcamera/base/object.h>
#include <libcamera/base/utils.h>

#include <libcamera/camera.h>
#include <libcamera/formats.h>

#include "libcamera/internal/formats.h"

#include "v4l2_camera.h"
#include "v4l2_camera_file.h"
#include "v4l2_compat_manager.h"

#define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c))

using namespace libcamera;

LOG_DECLARE_CATEGORY(V4L2Compat)

V4L2CameraProxy::V4L2CameraProxy(unsigned int index,
				 std::shared_ptr<Camera> camera)
	: refcount_(0), index_(index), bufferCount_(0), currentBuf_(0),
	  vcam_(std::make_unique<V4L2Camera>(camera)), owner_(nullptr)
{
	querycap(camera);
}

int V4L2CameraProxy::open(V4L2CameraFile *file)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	if (refcount_++) {
		files_.insert(file);
		return 0;
	}

	/*
	 * We open the camera here, once, and keep it open until the last
	 * V4L2CameraFile is closed. The proxy is initially not owned by any
	 * file. The first file that calls reqbufs with count > 0 or s_fmt
	 * will become the owner, and no other file will be allowed to call
	 * buffer-related ioctls (except querybuf), set the format, or start or
	 * stop the stream until ownership is released with a call to reqbufs
	 * with count = 0.
	 */

	int ret = vcam_->open(&streamConfig_);
	if (ret < 0) {
		refcount_--;
		return ret;
	}

	setFmtFromConfig(streamConfig_);

	files_.insert(file);

	return 0;
}

void V4L2CameraProxy::close(V4L2CameraFile *file)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	files_.erase(file);

	release(file);

	if (--refcount_ > 0)
		return;

	vcam_->close();
}

void *V4L2CameraProxy::mmap(V4L2CameraFile *file, void *addr, size_t length,
			    int prot, int flags, off64_t offset)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	/*
	 * Mimic the videobuf2 behaviour, which requires PROT_READ and
	 * MAP_SHARED.
	 */
	if (!(prot & PROT_READ)) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	if (!(flags & MAP_SHARED)) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	unsigned int index = offset / sizeimage_;
	if (static_cast<off_t>(index * sizeimage_) != offset ||
	    length != sizeimage_) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	int fd = vcam_->getBufferFd(index);
	if (fd < 0) {
		errno = EINVAL;
		return MAP_FAILED;
	}

	void *map = V4L2CompatManager::instance()->fops().mmap(addr, length, prot,
							       flags, fd, 0);
	if (map == MAP_FAILED)
		return map;

	buffers_[index].flags |= V4L2_BUF_FLAG_MAPPED;
	mmaps_[map] = index;

	return map;
}

int V4L2CameraProxy::munmap(V4L2CameraFile *file, void *addr, size_t length)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	MutexLocker locker(proxyMutex_);

	auto iter = mmaps_.find(addr);
	if (iter == mmaps_.end() || length != sizeimage_) {
		errno = EINVAL;
		return -1;
	}

	if (V4L2CompatManager::instance()->fops().munmap(addr, length))
		LOG(V4L2Compat, Error) << "Failed to unmap " << addr
				       << " with length " << length;

	buffers_[iter->second].flags &= ~V4L2_BUF_FLAG_MAPPED;
	mmaps_.erase(iter);

	return 0;
}

bool V4L2CameraProxy::validateBufferType(uint32_t type)
{
	return type == V4L2_BUF_TYPE_VIDEO_CAPTURE;
}

bool V4L2CameraProxy::validateMemoryType(uint32_t memory)
{
	return memory == V4L2_MEMORY_MMAP;
}

void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
{
	const Size &size = streamConfig.size;

	v4l2PixFormat_.width        = size.width;
	v4l2PixFormat_.height       = size.height;
	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat)[0];
	v4l2PixFormat_.field        = V4L2_FIELD_NONE;
	v4l2PixFormat_.bytesperline = streamConfig.stride;
	v4l2PixFormat_.sizeimage    = streamConfig.frameSize;
	v4l2PixFormat_.colorspace   = V4L2_COLORSPACE_SRGB;
	v4l2PixFormat_.priv         = V4L2_PIX_FMT_PRIV_MAGIC;
	v4l2PixFormat_.ycbcr_enc    = V4L2_YCBCR_ENC_DEFAULT;
	v4l2PixFormat_.quantization = V4L2_QUANTIZATION_DEFAULT;
	v4l2PixFormat_.xfer_func    = V4L2_XFER_FUNC_DEFAULT;

	sizeimage_ = streamConfig.frameSize;
}

void V4L2CameraProxy::querycap(std::shared_ptr<Camera> camera)
{
	std::string driver = "libcamera";
	std::string bus_info = driver + ":" + std::to_string(index_);

	utils::strlcpy(reinterpret_cast<char *>(capabilities_.driver), driver.c_str(),
		       sizeof(capabilities_.driver));
	utils::strlcpy(reinterpret_cast<char *>(capabilities_.card), camera->id().c_str(),
		       sizeof(capabilities_.card));
	utils::strlcpy(reinterpret_cast<char *>(capabilities_.bus_info), bus_info.c_str(),
		       sizeof(capabilities_.bus_info));
	/* \todo Put this in a header/config somewhere. */
	capabilities_.version = KERNEL_VERSION(5, 2, 0);
	capabilities_.device_caps = V4L2_CAP_VIDEO_CAPTURE
				  | V4L2_CAP_STREAMING
				  | V4L2_CAP_EXT_PIX_FORMAT;
	capabilities_.capabilities = capabilities_.device_caps
				   | V4L2_CAP_DEVICE_CAPS;
	memset(capabilities_.reserved, 0, sizeof(capabilities_.reserved));
}

void V4L2CameraProxy::updateBuffers()
{
	std::vector<V4L2Camera::Buffer> completedBuffers = vcam_->completedBuffers();
	for (const V4L2Camera::Buffer &buffer : completedBuffers) {
		const FrameMetadata &fmd = buffer.data_;
		struct v4l2_buffer &buf = buffers_[buffer.index_];

		switch (fmd.status) {
		case FrameMetadata::FrameSuccess:
			buf.bytesused = std::accumulate(fmd.planes().begin(),
							fmd.planes().end(), 0,
							[](unsigned int total, const auto &plane) {
								return total + plane.bytesused;
							});
			buf.field = V4L2_FIELD_NONE;
			buf.timestamp.tv_sec = fmd.timestamp / 1000000000;
			buf.timestamp.tv_usec = (fmd.timestamp / 1000) % 1000000;
			buf.sequence = fmd.sequence;

			buf.flags |= V4L2_BUF_FLAG_DONE;
			break;
		case FrameMetadata::FrameError:
			buf.flags |= V4L2_BUF_FLAG_ERROR;
			break;
		default:
			break;
		}
	}
}

int V4L2CameraProxy::vidioc_querycap(V4L2CameraFile *file, struct v4l2_capability *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = capabilities_;

	return 0;
}

int V4L2CameraProxy::vidioc_enum_framesizes(V4L2CameraFile *file, struct v4l2_frmsizeenum *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->pixel_format);
	PixelFormat format = v4l2Format.toPixelFormat();
	/*
	 * \todo This might need to be expanded as few pipeline handlers
	 * report StreamFormats.
	 */
	const std::vector<Size> &frameSizes = streamConfig_.formats().sizes(format);

	if (arg->index >= frameSizes.size())
		return -EINVAL;

	arg->type = V4L2_FRMSIZE_TYPE_DISCRETE;
	arg->discrete.width = frameSizes[arg->index].width;
	arg->discrete.height = frameSizes[arg->index].height;
	memset(arg->reserved, 0, sizeof(arg->reserved));

	return 0;
}

int V4L2CameraProxy::vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type) ||
	    arg->index >= streamConfig_.formats().pixelformats().size())
		return -EINVAL;

	PixelFormat format = streamConfig_.formats().pixelformats()[arg->index];
	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format)[0];

	arg->flags = format == formats::MJPEG ? V4L2_FMT_FLAG_COMPRESSED : 0;
	utils::strlcpy(reinterpret_cast<char *>(arg->description),
		       v4l2Format.description(), sizeof(arg->description));
	arg->pixelformat = v4l2Format;

	memset(arg->reserved, 0, sizeof(arg->reserved));

	return 0;
}

int V4L2CameraProxy::vidioc_g_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	memset(&arg->fmt, 0, sizeof(arg->fmt));
	arg->fmt.pix = v4l2PixFormat_;

	return 0;
}

int V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
{
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->fmt.pix.pixelformat);
	PixelFormat format = v4l2Format.toPixelFormat();
	Size size(arg->fmt.pix.width, arg->fmt.pix.height);

	StreamConfiguration config;
	int ret = vcam_->validateConfiguration(format, size, &config);
	if (ret < 0) {
		LOG(V4L2Compat, Error)
			<< "Failed to negotiate a valid format: "
			<< format;
		return -EINVAL;
	}

	arg->fmt.pix.width        = config.size.width;
	arg->fmt.pix.height       = config.size.height;
	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
	arg->fmt.pix.field        = V4L2_FIELD_NONE;
	arg->fmt.pix.bytesperline = config.stride;
	arg->fmt.pix.sizeimage    = config.frameSize;
	arg->fmt.pix.colorspace   = V4L2_COLORSPACE_SRGB;
	arg->fmt.pix.priv         = V4L2_PIX_FMT_PRIV_MAGIC;
	arg->fmt.pix.ycbcr_enc    = V4L2_YCBCR_ENC_DEFAULT;
	arg->fmt.pix.quantization = V4L2_QUANTIZATION_DEFAULT;
	arg->fmt.pix.xfer_func    = V4L2_XFER_FUNC_DEFAULT;

	return 0;
}

int V4L2CameraProxy::vidioc_s_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	int ret = acquire(file);
	if (ret < 0)
		return ret;

	ret = tryFormat(arg);
	if (ret < 0)
		return ret;

	Size size(arg->fmt.pix.width, arg->fmt.pix.height);
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->fmt.pix.pixelformat);
	ret = vcam_->configure(&streamConfig_, size, v4l2Format.toPixelFormat(),
			       bufferCount_);
	if (ret < 0)
		return -EINVAL;

	setFmtFromConfig(streamConfig_);

	return 0;
}

int V4L2CameraProxy::vidioc_try_fmt(V4L2CameraFile *file, struct v4l2_format *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type))
		return -EINVAL;

	int ret = tryFormat(arg);
	if (ret < 0)
		return ret;

	return 0;
}

enum v4l2_priority V4L2CameraProxy::maxPriority()
{
	auto max = std::max_element(files_.begin(), files_.end(),
				    [](const V4L2CameraFile *a, const V4L2CameraFile *b) {
					    return a->priority() < b->priority();
				    });
	return max != files_.end() ? (*max)->priority() : V4L2_PRIORITY_UNSET;
}

int V4L2CameraProxy::vidioc_g_priority(V4L2CameraFile *file, enum v4l2_priority *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = maxPriority();

	return 0;
}

int V4L2CameraProxy::vidioc_s_priority(V4L2CameraFile *file, enum v4l2_priority *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (*arg > V4L2_PRIORITY_RECORD)
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	file->setPriority(*arg);

	return 0;
}

int V4L2CameraProxy::vidioc_enuminput(V4L2CameraFile *file, struct v4l2_input *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index != 0)
		return -EINVAL;

	memset(arg, 0, sizeof(*arg));

	utils::strlcpy(reinterpret_cast<char *>(arg->name),
		       reinterpret_cast<char *>(capabilities_.card),
		       sizeof(arg->name));
	arg->type = V4L2_INPUT_TYPE_CAMERA;

	return 0;
}

int V4L2CameraProxy::vidioc_g_input(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	*arg = 0;

	return 0;
}

int V4L2CameraProxy::vidioc_s_input(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (*arg != 0)
		return -EINVAL;

	return 0;
}

void V4L2CameraProxy::freeBuffers()
{
	vcam_->freeBuffers();
	buffers_.clear();
	bufferCount_ = 0;
}

int V4L2CameraProxy::vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuffers *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	LOG(V4L2Compat, Debug) << arg->count << " buffers requested ";

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file) && owner_)
		return -EBUSY;

	arg->capabilities = V4L2_BUF_CAP_SUPPORTS_MMAP;
	arg->flags = 0;
	memset(arg->reserved, 0, sizeof(arg->reserved));

	if (arg->count == 0) {
		/* \todo Add buffer orphaning support */
		if (!mmaps_.empty())
			return -EBUSY;

		if (vcam_->isRunning())
			return -EBUSY;

		freeBuffers();
		release(file);

		return 0;
	}

	if (bufferCount_ > 0)
		freeBuffers();

	Size size(v4l2PixFormat_.width, v4l2PixFormat_.height);
	V4L2PixelFormat v4l2Format = V4L2PixelFormat(v4l2PixFormat_.pixelformat);
	int ret = vcam_->configure(&streamConfig_, size,
				   v4l2Format.toPixelFormat(), arg->count);
	if (ret < 0)
		return -EINVAL;

	setFmtFromConfig(streamConfig_);

	arg->count = streamConfig_.bufferCount;
	bufferCount_ = arg->count;

	ret = vcam_->allocBuffers(arg->count);
	if (ret < 0) {
		arg->count = 0;
		return ret;
	}

	buffers_.resize(arg->count);
	for (unsigned int i = 0; i < arg->count; i++) {
		struct v4l2_buffer buf = {};
		buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buf.length = v4l2PixFormat_.sizeimage;
		buf.memory = V4L2_MEMORY_MMAP;
		buf.m.offset = i * v4l2PixFormat_.sizeimage;
		buf.index = i;
		buf.flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;

		buffers_[i] = buf;
	}

	LOG(V4L2Compat, Debug) << "Allocated " << arg->count << " buffers";

	acquire(file);

	return 0;
}

int V4L2CameraProxy::vidioc_querybuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    arg->index >= bufferCount_)
		return -EINVAL;

	updateBuffers();

	*arg = buffers_[arg->index];

	return 0;
}

int V4L2CameraProxy::vidioc_prepare_buf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__
		<< "(index=" << arg->index << ")";

	if (!hasOwnership(file))
		return -EBUSY;

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (arg->flags & V4L2_BUF_FLAG_REQUEST_FD)
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	struct v4l2_buffer &buffer = buffers_[arg->index];

	if (buffer.flags & V4L2_BUF_FLAG_QUEUED ||
	    buffer.flags & V4L2_BUF_FLAG_PREPARED)
		return -EINVAL;

	buffer.flags |= V4L2_BUF_FLAG_PREPARED;

	arg->flags = buffer.flags;

	return 0;
}

int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *file, struct v4l2_buffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__
		<< "(index=" << arg->index << ")";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (buffers_[arg->index].flags & V4L2_BUF_FLAG_QUEUED)
		return -EINVAL;

	if (!hasOwnership(file))
		return -EBUSY;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory) ||
	    arg->index >= bufferCount_)
		return -EINVAL;

	int ret = vcam_->qbuf(arg->index);
	if (ret < 0)
		return ret;

	buffers_[arg->index].flags |= V4L2_BUF_FLAG_QUEUED;

	arg->flags = buffers_[arg->index].flags;

	return ret;
}

int V4L2CameraProxy::vidioc_dqbuf(V4L2CameraFile *file, struct v4l2_buffer *arg,
				  Mutex *lock)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (!hasOwnership(file))
		return -EBUSY;

	if (!vcam_->isRunning())
		return -EINVAL;

	if (!validateBufferType(arg->type) ||
	    !validateMemoryType(arg->memory))
		return -EINVAL;

	if (!file->nonBlocking()) {
		lock->unlock();
		vcam_->waitForBufferAvailable();
		lock->lock();
	} else if (!vcam_->isBufferAvailable())
		return -EAGAIN;

	/*
	 * We need to check here again in case stream was turned off while we
	 * were blocked on waitForBufferAvailable().
	 */
	if (!vcam_->isRunning())
		return -EINVAL;

	updateBuffers();

	struct v4l2_buffer &buf = buffers_[currentBuf_];

	buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE | V4L2_BUF_FLAG_PREPARED);
	buf.length = sizeimage_;
	*arg = buf;

	currentBuf_ = (currentBuf_ + 1) % bufferCount_;

	uint64_t data;
	int ret = ::read(file->efd(), &data, sizeof(data));
	if (ret != sizeof(data))
		LOG(V4L2Compat, Error) << "Failed to clear eventfd POLLIN";

	return 0;
}

int V4L2CameraProxy::vidioc_expbuf(V4L2CameraFile *file, struct v4l2_exportbuffer *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!hasOwnership(file))
		return -EBUSY;

	/* \todo Verify that the memory type is MMAP when adding DMABUF support */
	if (!validateBufferType(arg->type))
		return -EINVAL;

	if (arg->index >= bufferCount_)
		return -EINVAL;

	if (arg->flags & ~(O_CLOEXEC | O_ACCMODE))
		return -EINVAL;

	memset(arg->reserved, 0, sizeof(arg->reserved));

	/* \todo honor the O_ACCMODE flags passed to this function */
	arg->fd = fcntl(vcam_->getBufferFd(arg->index),
			arg->flags & O_CLOEXEC ? F_DUPFD_CLOEXEC : F_DUPFD, 0);

	return 0;
}

int V4L2CameraProxy::vidioc_streamon(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (bufferCount_ == 0)
		return -EINVAL;

	if (!validateBufferType(*arg))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file))
		return -EBUSY;

	if (vcam_->isRunning())
		return 0;

	currentBuf_ = 0;

	return vcam_->streamOn();
}

int V4L2CameraProxy::vidioc_streamoff(V4L2CameraFile *file, int *arg)
{
	LOG(V4L2Compat, Debug)
		<< "[" << file->description() << "] " << __func__ << "()";

	if (!validateBufferType(*arg))
		return -EINVAL;

	if (file->priority() < maxPriority())
		return -EBUSY;

	if (!hasOwnership(file) && owner_)
		return -EBUSY;

	int ret = vcam_->streamOff();

	for (struct v4l2_buffer &buf : buffers_)
		buf.flags &= ~(V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE);

	return ret;
}

const std::set<unsigned long> V4L2CameraProxy::supportedIoctls_ = {
	VIDIOC_QUERYCAP,
	VIDIOC_ENUM_FRAMESIZES,
	VIDIOC_ENUM_FMT,
	VIDIOC_G_FMT,
	VIDIOC_S_FMT,
	VIDIOC_TRY_FMT,
	VIDIOC_G_PRIORITY,
	VIDIOC_S_PRIORITY,
	VIDIOC_ENUMINPUT,
	VIDIOC_G_INPUT,
	VIDIOC_S_INPUT,
	VIDIOC_REQBUFS,
	VIDIOC_QUERYBUF,
	VIDIOC_PREPARE_BUF,
	VIDIOC_QBUF,
	VIDIOC_DQBUF,
	VIDIOC_EXPBUF,
	VIDIOC_STREAMON,
	VIDIOC_STREAMOFF,
};

int V4L2CameraProxy::ioctl(V4L2CameraFile *file, unsigned long longRequest, void *arg)
{
	MutexLocker locker(proxyMutex_);

	/*
	 * The Linux Kernel only processes 32 bits of an IOCTL.
	 *
	 * Prevent unexpected sign-extensions that could occur if applications
	 * use a signed int for the ioctl request, which would sign-extend to
	 * an incorrect value for unsigned longs on 64 bit architectures by
	 * explicitly casting as an unsigned int here.
	 */
	unsigned int request = longRequest;

	if (!arg && (_IOC_DIR(request) & _IOC_WRITE)) {
		errno = EFAULT;
		return -1;
	}

	if (supportedIoctls_.find(request) == supportedIoctls_.end()) {
		errno = ENOTTY;
		return -1;
	}

	if (!arg && (_IOC_DIR(request) & _IOC_READ)) {
		errno = EFAULT;
		return -1;
	}

	int ret;
	switch (request) {
	case VIDIOC_QUERYCAP:
		ret = vidioc_querycap(file, static_cast<struct v4l2_capability *>(arg));
		break;
	case VIDIOC_ENUM_FRAMESIZES:
		ret = vidioc_enum_framesizes(file, static_cast<struct v4l2_frmsizeenum *>(arg));
		break;
	case VIDIOC_ENUM_FMT:
		ret = vidioc_enum_fmt(file, static_cast<struct v4l2_fmtdesc *>(arg));
		break;
	case VIDIOC_G_FMT:
		ret = vidioc_g_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_S_FMT:
		ret = vidioc_s_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_TRY_FMT:
		ret = vidioc_try_fmt(file, static_cast<struct v4l2_format *>(arg));
		break;
	case VIDIOC_G_PRIORITY:
		ret = vidioc_g_priority(file, static_cast<enum v4l2_priority *>(arg));
		break;
	case VIDIOC_S_PRIORITY:
		ret = vidioc_s_priority(file, static_cast<enum v4l2_priority *>(arg));
		break;
	case VIDIOC_ENUMINPUT:
		ret = vidioc_enuminput(file, static_cast<struct v4l2_input *>(arg));
		break;
	case VIDIOC_G_INPUT:
		ret = vidioc_g_input(file, static_cast<int *>(arg));
		break;
	case VIDIOC_S_INPUT:
		ret = vidioc_s_input(file, static_cast<int *>(arg));
		break;
	case VIDIOC_REQBUFS:
		ret = vidioc_reqbufs(file, static_cast<struct v4l2_requestbuffers *>(arg));
		break;
	case VIDIOC_QUERYBUF:
		ret = vidioc_querybuf(file, static_cast<struct v4l2_buffer *>(arg));
		break;
	case VIDIOC_QBUF:
		ret = vidioc_qbuf(file, static_cast<struct v4l2_buffer *>(arg));
		break;
	case VIDIOC_DQBUF:
		ret = vidioc_dqbuf(file, static_cast<struct v4l2_buffer *>(arg), &proxyMutex_);
		break;
	case VIDIOC_EXPBUF:
		ret = vidioc_expbuf(file, static_cast<struct v4l2_exportbuffer *>(arg));
		break;
	case VIDIOC_STREAMON:
		ret = vidioc_streamon(file, static_cast<int *>(arg));
		break;
	case VIDIOC_STREAMOFF:
		ret = vidioc_streamoff(file, static_cast<int *>(arg));
		break;
	default:
		ret = -ENOTTY;
		break;
	}

	if (ret < 0) {
		errno = -ret;
		return -1;
	}

	return ret;
}

bool V4L2CameraProxy::hasOwnership(V4L2CameraFile *file)
{
	return owner_ == file;
}

/**
 * \brief Acquire exclusive ownership of the V4L2Camera
 *
 * \return Zero on success or if already acquired, and negative error on
 * failure.
 *
 * This is sufficient for poll()ing for buffers. Events, however, are signaled
 * on the file level, so all fds must be signaled. poll()ing from a different
 * fd than the one that locks the device is a corner case, and is currently not
 * supported.
 */
int V4L2CameraProxy::acquire(V4L2CameraFile *file)
{
	if (owner_ == file)
		return 0;

	if (owner_)
		return -EBUSY;

	vcam_->bind(file->efd());

	owner_ = file;

	return 0;
}

void V4L2CameraProxy::release(V4L2CameraFile *file)
{
	if (owner_ != file)
		return;

	vcam_->unbind();

	owner_ = nullptr;
}