src/android

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_videodevice.cpp - V4L2 Video Device
 */

#include "libcamera/internal/v4l2_videodevice.h"

#include <fcntl.h>
#include <iomanip>
#include <sstream>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <unistd.h>
#include <vector>

#include <linux/version.h>

#include <libcamera/event_notifier.h>
#include <libcamera/file_descriptor.h>

#include "libcamera/internal/log.h"
#include "libcamera/internal/media_device.h"
#include "libcamera/internal/media_object.h"
#include "libcamera/internal/utils.h"

/**
 * \file v4l2_videodevice.h
 * \brief V4L2 Video Device
 */
namespace libcamera {

LOG_DECLARE_CATEGORY(V4L2)

/**
 * \struct V4L2Capability
 * \brief struct v4l2_capability object wrapper and helpers
 *
 * The V4L2Capability structure manages the information returned by the
 * VIDIOC_QUERYCAP ioctl.
 */

/**
 * \fn V4L2Capability::driver()
 * \brief Retrieve the driver module name
 * \return The string containing the name of the driver module
 */

/**
 * \fn V4L2Capability::card()
 * \brief Retrieve the video device card name
 * \return The string containing the video device name
 */

/**
 * \fn V4L2Capability::bus_info()
 * \brief Retrieve the location of the video device in the system
 * \return The string containing the video device location
 */

/**
 * \fn V4L2Capability::device_caps()
 * \brief Retrieve the capabilities of the video device
 * \return The video device specific capabilities if V4L2_CAP_DEVICE_CAPS is
 * set or driver capabilities otherwise
 */

/**
 * \fn V4L2Capability::isMultiplanar()
 * \brief Identify if the video device implements the V4L2 multiplanar APIs
 * \return True if the video device supports multiplanar APIs
 */

/**
 * \fn V4L2Capability::isCapture()
 * \brief Identify if the video device captures data
 * \return True if the video device can capture data
 */

/**
 * \fn V4L2Capability::isOutput()
 * \brief Identify if the video device outputs data
 * \return True if the video device can output data
 */

/**
 * \fn V4L2Capability::isVideo()
 * \brief Identify if the video device captures or outputs images
 * \return True if the video device can capture or output images
 */

/**
 * \fn V4L2Capability::isM2M()
 * \brief Identify if the device is a Memory-to-Memory device
 * \return True if the device can capture and output images using the M2M API
 */

/**
 * \fn V4L2Capability::isMeta()
 * \brief Identify if the video device captures or outputs image meta-data
 * \return True if the video device can capture or output image meta-data
 */

/**
 * \fn V4L2Capability::isVideoCapture()
 * \brief Identify if the video device captures images
 * \return True if the video device can capture images
 */

/**
 * \fn V4L2Capability::isVideoOutput()
 * \brief Identify if the video device outputs images
 * \return True if the video device can output images
 */

/**
 * \fn V4L2Capability::isMetaCapture()
 * \brief Identify if the video device captures image meta-data
 * \return True if the video device can capture image meta-data
 */

/**
 * \fn V4L2Capability::isMetaOutput()
 * \brief Identify if the video device outputs image meta-data
 * \return True if the video device can output image meta-data
 */

/**
 * \fn V4L2Capability::hasStreaming()
 * \brief Determine if the video device can perform Streaming I/O
 * \return True if the video device provides Streaming I/O IOCTLs
 */

/**
 * \class V4L2BufferCache
 * \brief Hot cache of associations between V4L2 buffer indexes and FrameBuffer
 *
 * When importing buffers, V4L2 performs lazy mapping of dmabuf instances at
 * VIDIOC_QBUF (or VIDIOC_PREPARE_BUF) time and keeps the mapping associated
 * with the V4L2 buffer, as identified by its index. If the same V4L2 buffer is
 * then reused and queued with different dmabufs, the old dmabufs will be
 * unmapped and the new ones mapped. To keep this process efficient, it is
 * crucial to consistently use the same V4L2 buffer for given dmabufs through
 * the whole duration of a capture cycle.
 *
 * The V4L2BufferCache class keeps a map of previous dmabufs to V4L2 buffer
 * index associations to help selecting V4L2 buffers. It tracks, for every
 * entry, if the V4L2 buffer is in use, and offers lookup of the best free V4L2
 * buffer for a set of dmabufs.
 */

/**
 * \brief Create an empty cache with \a numEntries entries
 * \param[in] numEntries Number of entries to reserve in the cache
 *
 * Create a cache with \a numEntries entries all marked as unused. The entries
 * will be populated as the cache is used. This is typically used to implement
 * buffer import, with buffers added to the cache as they are queued.
 */
V4L2BufferCache::V4L2BufferCache(unsigned int numEntries)
	: lastUsedCounter_(1), missCounter_(0)
{
	cache_.resize(numEntries);
}

/**
 * \brief Create a pre-populated cache
 * \param[in] buffers Array of buffers to pre-populated with
 *
 * Create a cache pre-populated with \a buffers. This is typically used to
 * implement buffer export, with all buffers added to the cache when they are
 * allocated.
 */
V4L2BufferCache::V4L2BufferCache(const std::vector<std::unique_ptr<FrameBuffer>> &buffers)
	: lastUsedCounter_(1), missCounter_(0)
{
	for (const std::unique_ptr<FrameBuffer> &buffer : buffers)
		cache_.emplace_back(true,
				    lastUsedCounter_.fetch_add(1, std::memory_order_acq_rel),
				    buffer->planes());
}

V4L2BufferCache::~V4L2BufferCache()
{
	if (missCounter_ > cache_.size())
		LOG(V4L2, Debug) << "Cache misses: " << missCounter_;
}

/**
 * \brief Find the best V4L2 buffer for a FrameBuffer
 * \param[in] buffer The FrameBuffer
 *
 * Find the best V4L2 buffer index to be used for the FrameBuffer \a buffer
 * based on previous mappings of frame buffers to V4L2 buffers. If a free V4L2
 * buffer previously used with the same dmabufs as \a buffer is found in the
 * cache, return its index. Otherwise return the index of the first free V4L2
 * buffer and record its association with the dmabufs of \a buffer.
 *
 * \return The index of the best V4L2 buffer, or -ENOENT if no free V4L2 buffer
 * is available
 */
int V4L2BufferCache::get(const FrameBuffer &buffer)
{
	bool hit = false;
	int use = -1;
	uint64_t oldest = UINT64_MAX;

	for (unsigned int index = 0; index < cache_.size(); index++) {
		const Entry &entry = cache_[index];

		if (!entry.free)
			continue;

		/* Try to find a cache hit by comparing the planes. */
		if (entry == buffer) {
			hit = true;
			use = index;
			break;
		}

		if (entry.lastUsed < oldest) {
			use = index;
			oldest = entry.lastUsed;
		}
	}

	if (!hit)
		missCounter_++;

	if (use < 0)
		return -ENOENT;

	cache_[use] = Entry(false,
			    lastUsedCounter_.fetch_add(1, std::memory_order_acq_rel),
			    buffer);

	return use;
}

/**
 * \brief Mark buffer \a index as free in the cache
 * \param[in] index The V4L2 buffer index
 */
void V4L2BufferCache::put(unsigned int index)
{
	ASSERT(index < cache_.size());
	cache_[index].free = true;
}

V4L2BufferCache::Entry::Entry()
	: free(true), lastUsed(0)
{
}

V4L2BufferCache::Entry::Entry(bool free, uint64_t lastUsed, const FrameBuffer &buffer)
	: free(free), lastUsed(lastUsed)
{
	for (const FrameBuffer::Plane &plane : buffer.planes())
		planes_.emplace_back(plane);
}

bool V4L2BufferCache::Entry::operator==(const FrameBuffer &buffer) const
{
	const std::vector<FrameBuffer::Plane> &planes = buffer.planes();

	if (planes_.size() != planes.size())
		return false;

	for (unsigned int i = 0; i < planes.size(); i++)
		if (planes_[i].fd != planes[i].fd.fd() ||
		    planes_[i].length != planes[i].length)
			return false;
	return true;
}

/**
 * \class V4L2DeviceFormat
 * \brief The V4L2 video device image format and sizes
 *
 * This class describes the image format and resolution to be programmed on a
 * V4L2 video device. The image format is defined by a fourcc code (as specified
 * by the V4L2 API with the V4L2_PIX_FMT_* macros), a resolution (width and
 * height) and one to three planes with configurable line stride and a total
 * per-plane size in bytes.
 *
 * Image formats, as defined by the V4L2 APIs, are categorised as packed,
 * semi-planar and planar, and describe the layout of the image pixel components
 * stored in memory.
 *
 * Packed image formats store pixel components one after the other, in a
 * contiguous memory area. Examples of packed image formats are YUYV
 * permutations, RGB with different pixel sub-sampling ratios such as RGB565 or
 * RGB666 or Raw-Bayer formats such as SRGGB8 or SGRBG12.
 *
 * Semi-planar and planar image formats store the pixel components in separate
 * and possibly non-contiguous memory areas, named planes, whose sizes depend on
 * the pixel components sub-sampling ratios, which are defined by the format.
 * Semi-planar formats use two planes to store pixel components and notable
 * examples of such formats are the NV12 and NV16 formats, while planar formats
 * use three planes to store pixel components and notable examples are YUV422
 * and YUV420.
 *
 * Image formats supported by the V4L2 API are defined and described in Section
 * number 2 of the "Part I - Video for Linux API" chapter of the "Linux Media
 * Infrastructure userspace API", part of the Linux kernel documentation.
 *
 * In the context of this document, packed image formats are referred to as
 * "packed formats" and semi-planar and planar image formats are referred to as
 * "planar formats".
 *
 * V4L2 also defines two different sets of APIs to work with devices that store
 * planes in contiguous or separate memory areas. They are named "Single-plane
 * APIs" and "Multi-plane APIs" respectively and are documented in Section 2.1
 * and Section 2.2 of the above mentioned "Part I - Video for Linux API"
 * documentation.
 *
 * The single-plane API allows, among other parameters, the configuration of the
 * image resolution, the pixel format and the stride length. In that case the
 * stride applies to all planes (possibly sub-sampled). The multi-plane API
 * allows configuring the resolution, the pixel format and a per-plane stride
 * length and total size.
 *
 * Packed image formats, which occupy a single memory area, are easily described
 * through the single-plane API. When used on a video device that implements the
 * multi-plane API, only the size and stride information contained in the first
 * plane are taken into account.
 *
 * Planar image formats, which occupy distinct memory areas, are easily
 * described through the multi-plane APIs. When used on a video device that
 * implements the single-plane API, all planes are stored one after the other
 * in a contiguous memory area, and it is not possible to configure per-plane
 * stride length and size, but only a global stride length which is applied to
 * all planes.
 *
 * The V4L2DeviceFormat class describes both packed and planar image formats,
 * regardless of the API type (single or multi plane) implemented by the video
 * device the format has to be applied to. The total size and bytes per line
 * of images represented with packed formats are configured using the first
 * entry of the V4L2DeviceFormat::planes array, while the per-plane size and
 * per-plane stride length of images represented with planar image formats are
 * configured using the opportune number of entries of the
 * V4L2DeviceFormat::planes array, as prescribed by the image format
 * definition (semi-planar formats use 2 entries, while planar formats use the
 * whole 3 entries). The number of valid entries of the
 * V4L2DeviceFormat::planes array is defined by the
 * V4L2DeviceFormat::planesCount value.
 */

/**
 * \var V4L2DeviceFormat::size
 * \brief The image size in pixels
 */

/**
 * \var V4L2DeviceFormat::fourcc
 * \brief The fourcc code describing the pixel encoding scheme
 *
 * The fourcc code, as defined by the V4L2 API with the V4L2_PIX_FMT_* macros,
 * that identifies the image format pixel encoding scheme.
 */

/**
 * \var V4L2DeviceFormat::planes
 * \brief The per-plane memory size information
 *
 * Images are stored in memory in one or more data planes. Each data plane has a
 * specific line stride and memory size, which could differ from the image
 * visible sizes to accommodate padding at the end of lines and end of planes.
 * Only the first \ref planesCount entries are considered valid.
 */

/**
 * \var V4L2DeviceFormat::planesCount
 * \brief The number of valid data planes
 */

/**
 * \brief Assemble and return a string describing the format
 * \return A string describing the V4L2DeviceFormat
 */
const std::string V4L2DeviceFormat::toString() const
{
	std::stringstream ss;
	ss << size.toString() << "-" << fourcc.toString();
	return ss.str();
}

/**
 * \class V4L2VideoDevice
 * \brief V4L2VideoDevice object and API
 *
 * The V4L2VideoDevice class models an instance of a V4L2 video device.
 * It is constructed with the path to a V4L2 video device node. The device node
 * is only opened upon a call to open() which must be checked for success.
 *
 * The video device capabilities are validated when the device is opened and the
 * device is rejected if it is not a suitable V4L2 capture or output video
 * device, or if the video device does not support streaming I/O.
 *
 * No API call other than open(), isOpen() and close() shall be called on an
 * unopened device instance.
 *
 * The V4L2VideoDevice class supports the V4L2 MMAP and DMABUF memory types:
 *
 * - The allocateBuffers() function wraps buffer allocation with the V4L2 MMAP
 *   memory type. It requests buffers from the driver, allocating the
 *   corresponding memory, and exports them as a set of FrameBuffer objects.
 *   Upon successful return the driver's internal buffer management is
 *   initialized in MMAP mode, and the video device is ready to accept
 *   queueBuffer() calls.
 *
 *   This is the most traditional V4L2 buffer management, and is mostly useful
 *   to support internal buffer pools in pipeline handlers, either for CPU
 *   consumption (such as statistics or parameters pools), or for internal
 *   image buffers shared between devices.
 *
 * - The exportBuffers() function operates similarly to allocateBuffers(), but
 *   leaves the driver's internal buffer management uninitialized. It uses the
 *   V4L2 buffer orphaning support to allocate buffers with the MMAP method,
 *   export them as a set of FrameBuffer objects, and reset the driver's
 *   internal buffer management. The video device shall be initialized with
 *   importBuffers() or allocateBuffers() before it can accept queueBuffer()
 *   calls. The exported buffers are directly usable with any V4L2 video device
 *   in DMABUF mode, or with other dmabuf importers.
 *
 *   This method is mostly useful to implement buffer allocation helpers or to
 *   allocate ancillary buffers, when a V4L2 video device is used in DMABUF
 *   mode but no other source of buffers is available. An example use case
 *   would be allocation of scratch buffers to be used in case of buffer
 *   underruns on a video device that is otherwise supplied with external
 *   buffers.
 *
 * - The importBuffers() function initializes the driver's buffer management to
 *   import buffers in DMABUF mode. It requests buffers from the driver, but
 *   doesn't allocate memory. Upon successful return, the video device is ready
 *   to accept queueBuffer() calls. The buffers to be imported are provided to
 *   queueBuffer(), and may be supplied externally, or come from a previous
 *   exportBuffers() call.
 *
 *   This is the usual buffers initialization method for video devices whose
 *   buffers are exposed outside of libcamera. It is also typically used on one
 *   of the two video device that participate in buffer sharing inside
 *   pipelines, the other video device typically using allocateBuffers().
 *
 * - The releaseBuffers() function resets the driver's internal buffer
 *   management that was initialized by a previous call to allocateBuffers() or
 *   importBuffers(). Any memory allocated by allocateBuffers() is freed.
 *   Buffer exported by exportBuffers() are not affected by this function.
 *
 * The V4L2VideoDevice class tracks queued buffers and handles buffer events. It
 * automatically dequeues completed buffers and emits the \ref bufferReady
 * signal.
 *
 * Upon destruction any device left open will be closed, and any resources
 * released.
 *
 * \context This class is \threadbound.
 */

/**
 * \brief Construct a V4L2VideoDevice
 * \param[in] deviceNode The file-system path to the video device node
 */
V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
	: V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr),
	  fdEventNotifier_(nullptr), frameStartEnabled_(false)
{
	/*
	 * We default to an MMAP based CAPTURE video device, however this will
	 * be updated based upon the device capabilities.
	 */
	bufferType_ = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
	memoryType_ = V4L2_MEMORY_MMAP;
}

/**
 * \brief Construct a V4L2VideoDevice from a MediaEntity
 * \param[in] entity The MediaEntity to build the video device from
 *
 * Construct a V4L2VideoDevice from a MediaEntity's device node path.
 */
V4L2VideoDevice::V4L2VideoDevice(const MediaEntity *entity)
	: V4L2VideoDevice(entity->deviceNode())
{
}

V4L2VideoDevice::~V4L2VideoDevice()
{
	close();
}

/**
 * \brief Open the V4L2 video device node and query its capabilities
 *
 * \return 0 on success or a negative error code otherwise
 */
int V4L2VideoDevice::open()
{
	int ret;

	ret = V4L2Device::open(O_RDWR | O_NONBLOCK);
	if (ret < 0)
		return ret;

	ret = ioctl(VIDIOC_QUERYCAP, &caps_);
	if (ret < 0) {
		LOG(V4L2, Error)
			<< "Failed to query device capabilities: "
			<< strerror(-ret);
		return ret;
	}

	if (caps_.version < KERNEL_VERSION(5, 0, 0)) {
		LOG(V4L2, Error)
			<< "V4L2 API v" << (caps_.version >> 16)
			<< "." << ((caps_.version >> 8) & 0xff)
			<< "." << (caps_.version & 0xff)
			<< " too old, v5.0.0 or later is required";
		return -EINVAL;
	}

	if (!caps_.hasStreaming()) {
		LOG(V4L2, Error) << "Device does not support streaming I/O";
		return -EINVAL;
	}

	/*
	 * Set buffer type and wait for read notifications on CAPTURE video
	 * devices (POLLIN), and write notifications for OUTPUT video devices
	 * (POLLOUT).
	 */
	EventNotifier::Type notifierType;

	if (caps_.isVideoCapture()) {
		notifierType = EventNotifier::Read;
		bufferType_ = caps_.isMultiplanar()
			    ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE
			    : V4L2_BUF_TYPE_VIDEO_CAPTURE;
	} else if (caps_.isVideoOutput()) {
		notifierType = EventNotifier::Write;
		bufferType_ = caps_.isMultiplanar()
			    ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
			    : V4L2_BUF_TYPE_VIDEO_OUTPUT;
	} else if (caps_.isMetaCapture()) {
		notifierType = EventNotifier::Read;
		bufferType_ = V4L2_BUF_TYPE_META_CAPTURE;
	} else if (caps_.isMetaOutput()) {
		notifierType = EventNotifier::Write;
		bufferType_ = V4L2_BUF_TYPE_META_OUTPUT;
	} else {
		LOG(V4L2, Error) << "Device is not a supported type";
		return -EINVAL;
	}

	fdBufferNotifier_ = new EventNotifier(fd(), notifierType);
	fdBufferNotifier_->activated.connect(this, &V4L2VideoDevice::bufferAvailable);
	fdBufferNotifier_->setEnabled(false);

	fdEventNotifier_ = new EventNotifier(fd(), EventNotifier::Exception);
	fdEventNotifier_->activated.connect(this, &V4L2VideoDevice::eventAvailable);
	fdEventNotifier_->setEnabled(false);

	LOG(V4L2, Debug)
		<< "Opened device " << caps_.bus_info() << ": "
		<< caps_.driver() << ": " << caps_.card();

	return 0;
}

/**
 * \brief Open a V4L2 video device from an opened file handle and query its
 * capabilities
 * \param[in] handle The file descriptor to set
 * \param[in] type The device type to operate on
 *
 * This methods opens a video device from the existing file descriptor \a
 * handle. Like open(), this method queries the capabilities of the device, but
 * handles it according to the given device \a type instead of determining its
 * type from the capabilities. This can be used to force a given device type for
 * memory-to-memory devices.
 *
 * The file descriptor \a handle is duplicated, and the caller is responsible
 * for closing the \a handle when it has no further use for it. The close()
 * method will close the duplicated file descriptor, leaving \a handle
 * untouched.
 *
 * \return 0 on success or a negative error code otherwise
 */
int V4L2VideoDevice::open(int handle, enum v4l2_buf_type type)
{
	int ret;
	int newFd;

	newFd = dup(handle);
	if (newFd < 0) {
		ret = -errno;
		LOG(V4L2, Error) << "Failed to duplicate file handle: "
				 << strerror(-ret);
		return ret;
	}

	ret = V4L2Device::setFd(newFd);
	if (ret < 0) {
		LOG(V4L2, Error) << "Failed to set file handle: "
				 << strerror(-ret);
		::close(newFd);
		return ret;
	}

	ret = ioctl(VIDIOC_QUERYCAP, &caps_);
	if (ret < 0) {
		LOG(V4L2, Error)
			<< "Failed to query device capabilities: "
			<< strerror(-ret);
		return ret;
	}

	if (!caps_.hasStreaming()) {
		LOG(V4L2, Error) << "Device does not support streaming I/O";
		return -EINVAL;
	}

	/*
	 * Set buffer type and wait for read notifications on CAPTURE video
	 * devices (POLLIN), and write notifications for OUTPUT video devices
	 * (POLLOUT).
	 */
	EventNotifier::Type notifierType;

	switch (type) {
	case V4L2_BUF_TYPE_VIDEO_OUTPUT:
		notifierType = EventNotifier::Write;
		bufferType_ = caps_.isMultiplanar()
			    ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
			    : V4L2_BUF_TYPE_VIDEO_OUTPUT;
		break;
	case V4L2_BUF_TYPE_VIDEO_CAPTURE:
		notifierType = EventNotifier::Read;
		bufferType_ = caps_.isMultiplanar()
			    ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE
			    : V4L2_BUF_TYPE_VIDEO_CAPTURE;
		break;
	default:
		LOG(V4L2, Error) << "Unsupported buffer type";
		return -EINVAL;
	}

	fdBufferNotifier_ = new EventNotifier(fd(), notifierType);
	fdBufferNotifier_->activated.connect(this, &V4L2VideoDevice::bufferAvailable);
	fdBufferNotifier_->setEnabled(false);

	fdEventNotifier_ = new EventNotifier(fd(), EventNotifier::Exception);
	fdEventNotifier_->activated.connect(this, &V4L2VideoDevice::eventAvailable);
	fdEventNotifier_->setEnabled(false);

	LOG(V4L2, Debug)
		<< "Opened device " << caps_.bus_info() << ": "
		<< caps_.driver() << ": " << caps_.card();

	return 0;
}

/**
 * \brief Close the video device, releasing any resources acquired by open()
 */
void V4L2VideoDevice::close()
{
	if (!isOpen())
		return;

	releaseBuffers();
	delete fdBufferNotifier_;
	delete fdEventNotifier_;

	V4L2Device::close();
}

/**
 * \fn V4L2VideoDevice::driverName()
 * \brief Retrieve the name of the V4L2 device driver
 * \return The string containing the driver name
 */

/**
 * \fn V4L2VideoDevice::deviceName()
 * \brief Retrieve the name of the V4L2 video device
 * \return The string containing the device name
 */

/**
 * \fn V4L2VideoDevice::busName()
 * \brief Retrieve the location of the device in the system
 * \return The string containing the device location
 */

/**
 * \fn V4L2VideoDevice::caps()
 * \brief Retrieve the device V4L2 capabilities
 * \return The device V4L2 capabilities
 */

std::string V4L2VideoDevice::logPrefix() const
{
	return deviceNode() + (V4L2_TYPE_IS_OUTPUT(bufferType_) ? "[out]" : "[cap]");
}

/**
 * \brief Retrieve the image format set on the V4L2 video device
 * \param[out] format The image format applied on the video device
 * \return 0 on success or a negative error code otherwise
 */
int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
{
	if (caps_.isMeta())
		return getFormatMeta(format);
	else if (caps_.isMultiplanar())
		return getFormatMultiplane(format);
	else
		return getFormatSingleplane(format);
}

/**
 * \brief Configure an image format on the V4L2 video device
 * \param[inout] format The image format to apply to the video device
 *
 * Apply the supplied \a format to the video device, and return the actually
 * applied format parameters, as \ref V4L2VideoDevice::getFormat would do.
 *
 * \return 0 on success or a negative error code otherwise
 */
int V4L2VideoDevice::setFormat(V4L2DeviceFormat *format)
{
	if (caps_.isMeta())
		return setFormatMeta(format);
	else if (caps_.isMultiplanar())
		return setFormatMultiplane(format);
	else
		return setFormatSingleplane(format);
}

int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_meta_format *pix = &v4l2Format.fmt.meta;
	int ret;

	v4l2Format.type = bufferType_;
	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
		return ret;
	}

	format->size.width = 0;
	format->size.height = 0;
	format->fourcc = V4L2PixelFormat(pix->dataformat);
	format->planesCount = 1;
	format->planes[0].bpl = pix->buffersize;
	format->planes[0].size = pix->buffersize;

	return 0;
}

int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_meta_format *pix = &v4l2Format.fmt.meta;
	int ret;

	v4l2Format.type = bufferType_;
	pix->dataformat = format->fourcc;
	pix->buffersize = format->planes[0].size;
	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
		return ret;
	}

	/*
	 * Return to caller the format actually applied on the video device,
	 * which might differ from the requested one.
	 */
	format->size.width = 0;
	format->size.height = 0;
	format->fourcc = V4L2PixelFormat(pix->dataformat);
	format->planesCount = 1;
	format->planes[0].bpl = pix->buffersize;
	format->planes[0].size = pix->buffersize;

	return 0;
}

int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_pix_format_mplane *pix = &v4l2Format.fmt.pix_mp;
	int ret;

	v4l2Format.type = bufferType_;
	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
		return ret;
	}

	format->size.width = pix->width;
	format->size.height = pix->height;
	format->fourcc = V4L2PixelFormat(pix->pixelformat);
	format->planesCount = pix->num_planes;

	for (unsigned int i = 0; i < format->planesCount; ++i) {
		format->planes[i].bpl = pix->plane_fmt[i].bytesperline;
		format->planes[i].size = pix->plane_fmt[i].sizeimage;
	}

	return 0;
}

int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_pix_format_mplane *pix = &v4l2Format.fmt.pix_mp;
	int ret;

	v4l2Format.type = bufferType_;
	pix->width = format->size.width;
	pix->height = format->size.height;
	pix->pixelformat = format->fourcc;
	pix->num_planes = format->planesCount;
	pix->field = V4L2_FIELD_NONE;

	for (unsigned int i = 0; i < pix->num_planes; ++i) {
		pix->plane_fmt[i].bytesperline = format->planes[i].bpl;
		pix->plane_fmt[i].sizeimage = format->planes[i].size;
	}

	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
		return ret;
	}

	/*
	 * Return to caller the format actually applied on the video device,
	 * which might differ from the requested one.
	 */
	format->size.width = pix->width;
	format->size.height = pix->height;
	format->fourcc = V4L2PixelFormat(pix->pixelformat);
	format->planesCount = pix->num_planes;
	for (unsigned int i = 0; i < format->planesCount; ++i) {
		format->planes[i].bpl = pix->plane_fmt[i].bytesperline;
		format->planes[i].size = pix->plane_fmt[i].sizeimage;
	}

	return 0;
}

int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_pix_format *pix = &v4l2Format.fmt.pix;
	int ret;

	v4l2Format.type = bufferType_;
	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
		return ret;
	}

	format->size.width = pix->width;
	format->size.height = pix->height;
	format->fourcc = V4L2PixelFormat(pix->pixelformat);
	format->planesCount = 1;
	format->planes[0].bpl = pix->bytesperline;
	format->planes[0].size = pix->sizeimage;

	return 0;
}

int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
{
	struct v4l2_format v4l2Format = {};
	struct v4l2_pix_format *pix = &v4l2Format.fmt.pix;
	int ret;

	v4l2Format.type = bufferType_;
	pix->width = format->size.width;
	pix->height = format->size.height;
	pix->pixelformat = format->fourcc;
	pix->bytesperline = format->planes[0].bpl;
	pix->field = V4L2_FIELD_NONE;
	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
	if (ret) {
		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
		return ret;
	}

	/*
	 * Return to caller the format actually applied on the device,
	 * which might differ from the requested one.
	 */
	format->size.width = pix->width;
	format->size.height = pix->height;
	format->fourcc = V4L2PixelFormat(pix->pixelformat);
	format->planesCount = 1;
	format->planes[0].bpl = pix->bytesperline;
	format->planes[0].size = pix->sizeimage;

	return 0;
}

/**
 * \brief Enumerate all pixel formats and frame sizes
 * \param[in] code Restrict formats to this media bus code.
 *
 * Enumerate all pixel formats and frame sizes supported by the video device.
 * If the \a code argument is not zero, only formats compatible with that media
 * bus code will be enumerated.
 *
 * \return A list of the supported video device formats
 */
std::map<V4L2PixelFormat, std::vector<SizeRange>> V4L2VideoDevice::formats(uint32_t code)
{
	std::map<V4L2PixelFormat, std::vector<SizeRange>> formats;

	for (V4L2PixelFormat pixelFormat : enumPixelformats(code)) {
		std::vector<SizeRange> sizes = enumSizes(pixelFormat);
		if (sizes.empty())
			return {};

		if (formats.find(pixelFormat) != formats.end()) {
			LOG(V4L2, Error)
				<< "Could not add sizes for pixel format "
				<< pixelFormat;
			return {};
		}

		formats.emplace(pixelFormat, sizes);
	}

	return formats;
}

std::vector<V4L2PixelFormat> V4L2VideoDevice::enumPixelformats(uint32_t code)
{
	std::vector<V4L2PixelFormat> formats;
	int ret;

	if (code && !(caps_.device_caps() & V4L2_CAP_IO_MC)) {
		LOG(V4L2, Error)
			<< "Media bus code filtering not supported by the device";
		return {};
	}

	for (unsigned int index = 0; ; index++) {
		struct v4l2_fmtdesc pixelformatEnum = {};
		pixelformatEnum.index = index;
		pixelformatEnum.type = bufferType_;
		pixelformatEnum.mbus_code = code;

		ret = ioctl(VIDIOC_ENUM_FMT, &pixelformatEnum);
		if (ret)
			break;

		formats.push_back(V4L2PixelFormat(pixelformatEnum.pixelformat));
	}

	if (ret && ret != -EINVAL) {
		LOG(V4L2, Error)
Age	Commit message (Expand)	Author
2020-09-20	android: jpeg: exif: Use reentrant localtime_r()	Laurent Pinchart
2020-09-18	android: camera_device: Make CameraStream a class	Jacopo Mondi
2020-09-18	android: camera_device: Set Encoder at construction	Jacopo Mondi
2020-09-18	android: camera_device: Rework CameraStream handling	Jacopo Mondi
2020-09-18	android: camera_device: Use Android format	Jacopo Mondi
2020-09-18	android: camera_device: Get rid of stream counter	Jacopo Mondi
2020-09-18	android: camera_device: Generate RAW resolutions	Jacopo Mondi
2020-09-18	android: camera_device: Break out size calculation	Jacopo Mondi
2020-09-18	android: camera_device: Add debug to stream initialization	Jacopo Mondi
2020-09-18	android: camera_device: Generate JPEG sizes	Jacopo Mondi
2020-09-18	android: camera_device: Refuse unsupported formats	Jacopo Mondi
2020-09-16	libcamera: Turn the android option into a feature	Laurent Pinchart
2020-09-16	android: Protect against null callbacks	Laurent Pinchart
2020-09-10	android: jpeg: Support an initial set of EXIF metadata tags	Umang Jain
2020-09-10	android: jpeg: Add EXIF infrastructure	Kieran Bingham
2020-09-10	android: camera_device: Fix value of orientation metadata	Umang Jain
2020-09-08	android: camera_device: Fix spelling in comment	Jacopo Mondi
2020-08-25	meson: Remove -Wno-unused-parameter	Laurent Pinchart
2020-08-25	libcamera: Remove void specifier for functions that take no arguments	Laurent Pinchart
2020-08-23	android: camera_hal_manager: Support camera hotplug	Umang Jain
2020-08-23	android: camera_device: Add a getter to get libcamera::Camera pointer	Umang Jain
2020-08-23	android: camera_device: Make CameraDevice a shared object	Umang Jain
2020-08-23	android: camera_hal_manager: Set camera module callbacks	Umang Jain
2020-08-14	libcamera: request: Declare a using directive for map of buffers	Niklas Söderlund
2020-08-06	android: camera_device: Support MJPEG stream construction	Kieran Bingham
2020-08-06	android: Introduce JPEG encoding	Kieran Bingham
2020-08-06	android: camera_device: Generate ResultMetadata earlier	Kieran Bingham
2020-08-06	android: camera_device: Report configuration changes from validate()	Kieran Bingham
2020-08-06	android: camera_device: Query plane length	Kieran Bingham
2020-08-06	android: camera_device: Only construct required planes	Kieran Bingham
2020-08-06	android: camera_device: Report an error in notifyError()	Kieran Bingham
2020-08-06	android: camera_device: Fix trivial spelling	Kieran Bingham
2020-08-06	android: camera_device: Initialize 'id_' field in constructor	Umang Jain
2020-08-06	android: camera_ops: Fix a documentation spelling typo	Umang Jain
2020-08-06	android: camera_hal_manager: Remove unused getStaticMetadata() method	Umang Jain
2020-08-05	libcamera: camera: Rename name() to id()	Niklas Söderlund
2020-08-05	android: camera_device: Fix preview template	Jacopo Mondi
2020-08-05	android: camera_device: Break-out request template	Jacopo Mondi
2020-08-05	android: camera_metadata: Add method to update an entry	Jacopo Mondi
2020-08-05	andrdid: camera_device: Store const templates	Jacopo Mondi
2020-08-05	android: camera_metadata: Add const version of get()	Jacopo Mondi
2020-08-05	android: camera_metadata: Mark isValid() as const	Jacopo Mondi
2020-08-03	android: camera_device: Report RAW capability if supported	Niklas Söderlund
2020-08-03	android: camera_device: Map HAL RAW to libcamera RAW formats	Niklas Söderlund
2020-08-03	android: camera_device: Prepare for non-mandatory formats	Niklas Söderlund
2020-07-24	android: camera_device: Add ANDROID_REQUEST_MAX_NUM_INPUT_STREAMS	Niklas Söderlund
2020-07-24	android: camera_device: Remove scaler format information from Camera3Format	Niklas Söderlund
2020-07-24	android: camera_device: Use HAL_PIXEL_FORMAT_* defines for formats	Niklas Söderlund
2020-07-24	android: camera_device: Remove ANDROID_SCALER_AVAILABLE_FORMATS	Niklas Söderlund
2020-07-07	android: camera_device: Remove single buffer restriction.	Kieran Bingham