src/android/mm

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * v4l2_device.cpp - Common base for V4L2 video devices and subdevices
 */

#include "libcamera/internal/v4l2_device.h"

#include <fcntl.h>
#include <iomanip>
#include <limits.h>
#include <map>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <vector>

#include <linux/v4l2-mediabus.h>

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

#include "libcamera/internal/formats.h"
#include "libcamera/internal/sysfs.h"

/**
 * \file v4l2_device.h
 * \brief Common base for V4L2 devices and subdevices
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(V4L2)

/**
 * \class V4L2Device
 * \brief Base class for V4L2VideoDevice and V4L2Subdevice
 *
 * The V4L2Device class groups together the functions and fields common to
 * both the V4L2VideoDevice and V4L2Subdevice classes, and provides a base
 * class with functions to open and close the device node associated with the
 * device and to perform IOCTL system calls on it.
 *
 * The V4L2Device class cannot be instantiated directly, as its constructor
 * is protected. Users should instead create instances of one the derived
 * classes to model either a V4L2 video device or a V4L2 subdevice.
 */

/**
 * \brief Construct a V4L2Device
 * \param[in] deviceNode The device node filesystem path
 *
 * Initialize the file descriptor to -1 and store the \a deviceNode to be used
 * at open() time, and the \a logTag to prefix log messages with.
 */
V4L2Device::V4L2Device(const std::string &deviceNode)
	: deviceNode_(deviceNode), fdEventNotifier_(nullptr),
	  frameStartEnabled_(false)
{
}

/**
 * \brief Destroy a V4L2Device
 */
V4L2Device::~V4L2Device()
{
}

/**
 * \brief Open a V4L2 device node
 * \param[in] flags Access mode flags
 *
 * Open the device node path with the provided access mode \a flags and
 * initialize the file descriptor, which was initially set to -1.
 *
 * \return 0 on success or a negative error code otherwise
 */
int V4L2Device::open(unsigned int flags)
{
	if (isOpen()) {
		LOG(V4L2, Error) << "Device already open";
		return -EBUSY;
	}

	UniqueFD fd(syscall(SYS_openat, AT_FDCWD, deviceNode_.c_str(),
			    flags | O_CLOEXEC));
	if (!fd.isValid()) {
		int ret = -errno;
		LOG(V4L2, Error) << "Failed to open V4L2 device '"
				 << deviceNode_ << "': "
				 << strerror(-ret);
		return ret;
	}

	setFd(std::move(fd));

	return 0;
}

/**
 * \brief Set the file descriptor of a V4L2 device
 * \param[in] fd The file descriptor handle
 *
 * This function allows a device to provide an already opened file descriptor
 * referring to the V4L2 device node, instead of opening it with open(). This
 * can be used for V4L2 M2M devices where a single video device node is used for
 * both the output and capture devices, or when receiving an open file
 * descriptor in a context that doesn't have permission to open the device node
 * itself.
 *
 * This function and the open() function are mutually exclusive, only one of the
 * two shall be used for a V4L2Device instance.
 *
 * \return 0 on success or a negative error code otherwise
 */
int V4L2Device::setFd(UniqueFD fd)
{
	if (isOpen())
		return -EBUSY;

	fd_ = std::move(fd);

	fdEventNotifier_ = new EventNotifier(fd_.get(), EventNotifier::Exception);
	fdEventNotifier_->activated.connect(this, &V4L2Device::eventAvailable);
	fdEventNotifier_->setEnabled(false);

	listControls();

	return 0;
}

/**
 * \brief Close the device node
 *
 * Reset the file descriptor to -1
 */
void V4L2Device::close()
{
	if (!isOpen())
		return;

	delete fdEventNotifier_;

	fd_.reset();
}

/**
 * \fn V4L2Device::isOpen()
 * \brief Check if the V4L2 device node is open
 * \return True if the V4L2 device node is open, false otherwise
 */

/**
 * \fn V4L2Device::controls()
 * \brief Retrieve the supported V4L2 controls and their information
 * \return A map of the V4L2 controls supported by the device
 */

/**
 * \brief Read controls from the device
 * \param[in] ids The list of controls to read, specified by their ID
 *
 * This function reads the value of all controls contained in \a ids, and
 * returns their values as a ControlList.
 *
 * If any control in \a ids is not supported by the device, is disabled (i.e.
 * has the V4L2_CTRL_FLAG_DISABLED flag set), or if any other error occurs
 * during validation of the requested controls, no control is read and this
 * function returns an empty control list.
 *
 * \return The control values in a ControlList on success, or an empty list on
 * error
 */
ControlList V4L2Device::getControls(const std::vector<uint32_t> &ids)
{
	if (ids.empty())
		return {};

	ControlList ctrls{ controls_ };

	for (uint32_t id : ids) {
		const auto iter = controls_.find(id);
		if (iter == controls_.end()) {
			LOG(V4L2, Error)
				<< "Control " << utils::hex(id) << " not found";
			return {};
		}

		ctrls.set(id, {});
	}

	std::vector<v4l2_ext_control> v4l2Ctrls(ids.size());
	memset(v4l2Ctrls.data(), 0, sizeof(v4l2_ext_control) * ctrls.size());

	unsigned int i = 0;
	for (auto &ctrl : ctrls) {
		unsigned int id = ctrl.first;
		const struct v4l2_query_ext_ctrl &info = controlInfo_[id];

		v4l2_ext_control &v4l2Ctrl = v4l2Ctrls[i++];
		v4l2Ctrl.id = id;

		if (info.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD) {
			ControlType type;

			switch (info.type) {
			case V4L2_CTRL_TYPE_U8:
				type = ControlTypeByte;
				break;

			default:
				LOG(V4L2, Error)
					<< "Unsupported payload control type "
					<< info.type;
				return {};
			}

			ControlValue &value = ctrl.second;
			value.reserve(type, true, info.elems);
			Span<uint8_t> data = value.data();

			v4l2Ctrl.p_u8 = data.data();
			v4l2Ctrl.size = data.size();
		}
	}

	struct v4l2_ext_controls v4l2ExtCtrls = {};
	v4l2ExtCtrls.which = V4L2_CTRL_WHICH_CUR_VAL;
	v4l2ExtCtrls.controls = v4l2Ctrls.data();
	v4l2ExtCtrls.count = v4l2Ctrls.size();

	int ret = ioctl(VIDIOC_G_EXT_CTRLS, &v4l2ExtCtrls);
	if (ret) {
		unsigned int errorIdx = v4l2ExtCtrls.error_idx;

		/* Generic validation error. */
		if (errorIdx == 0 || errorIdx >= v4l2Ctrls.size()) {
			LOG(V4L2, Error) << "Unable to read controls: "
					 << strerror(-ret);
			return {};
		}

		/* A specific control failed. */
		const unsigned int id = v4l2Ctrls[errorIdx].id;
		LOG(V4L2, Error) << "Unable to read control " << utils::hex(id)
				 << ": " << strerror(-ret);

		v4l2Ctrls.resize(errorIdx);
	}

	updateControls(&ctrls, v4l2Ctrls);

	return ctrls;
}

/**
 * \brief Write controls to the device
 * \param[in] ctrls The list of controls to write
 *
 * This function writes the value of all controls contained in \a ctrls, and
 * stores the values actually applied to the device in the corresponding
 * \a ctrls entry.
 *
 * If any control in \a ctrls is not supported by the device, is disabled (i.e.
 * has the V4L2_CTRL_FLAG_DISABLED flag set), is read-only, if any other error
 * occurs during validation of the requested controls, no control is written and
 * this function returns -EINVAL.
 *
 * If an error occurs while writing the controls, the index of the first
 * control that couldn't be written is returned. All controls below that index
 * are written and their values are updated in \a ctrls, while all other
 * controls are not written and their values are not changed.
 *
 * \return 0 on success or an error code otherwise
 * \retval -EINVAL One of the control is not supported or not accessible
 * \retval i The index of the control that failed
 */
int V4L2Device::setControls(ControlList *ctrls)
{
	if (ctrls->empty())
		return 0;

	std::vector<v4l2_ext_control> v4l2Ctrls(ctrls->size());
	memset(v4l2Ctrls.data(), 0, sizeof(v4l2_ext_control) * ctrls->size());

	for (auto [ctrl, i] = std::pair(ctrls->begin(), 0u); i < ctrls->size(); ctrl++, i++) {
		const unsigned int id = ctrl->first;
		const auto iter = controls_.find(id);
		if (iter == controls_.end()) {
			LOG(V4L2, Error)
				<< "Control " << utils::hex(id) << " not found";
			return -EINVAL;
		}
		v4l2_ext_control &v4l2Ctrl = v4l2Ctrls[i];
		v4l2Ctrl.id = id;

		/* Set the v4l2_ext_control value for the write operation. */
		ControlValue &value = ctrl->second;
		switch (iter->first->type()) {
		case ControlTypeInteger32: {
			if (value.isArray()) {
				Span<uint8_t> data = value.data();
				v4l2Ctrl.p_u32 = reinterpret_cast<uint32_t *>(data.data());
				v4l2Ctrl.size = data.size();
			} else {
				v4l2Ctrl.value = value.get<int32_t>();
			}

			break;
		}

		case ControlTypeInteger64:
			v4l2Ctrl.value64 = value.get<int64_t>();
			break;

		case ControlTypeByte: {
			if (!value.isArray()) {
				LOG(V4L2, Error)
					<< "Control " << utils::hex(id)
					<< " requires an array value";
				return -EINVAL;
			}

			Span<uint8_t> data = value.data();
			v4l2Ctrl.p_u8 = data.data();
			v4l2Ctrl.size = data.size();

			break;
		}

		default:
			/* \todo To be changed to support strings. */
			v4l2Ctrl.value = value.get<int32_t>();
			break;
		}
	}

	struct v4l2_ext_controls v4l2ExtCtrls = {};
	v4l2ExtCtrls.which = V4L2_CTRL_WHICH_CUR_VAL;
	v4l2ExtCtrls.controls = v4l2Ctrls.data();
	v4l2ExtCtrls.count = v4l2Ctrls.size();

	int ret = ioctl(VIDIOC_S_EXT_CTRLS, &v4l2ExtCtrls);
	if (ret) {
		unsigned int errorIdx = v4l2ExtCtrls.error_idx;

		/* Generic validation error. */
		if (errorIdx == 0 || errorIdx >= v4l2Ctrls.size()) {
			LOG(V4L2, Error) << "Unable to set controls: "
					 << strerror(-ret);
			return -EINVAL;
		}

		/* A specific control failed. */
		const unsigned int id = v4l2Ctrls[errorIdx].id;
		LOG(V4L2, Error) << "Unable to set control " << utils::hex(id)
				 << ": " << strerror(-ret);

		v4l2Ctrls.resize(errorIdx);
		ret = errorIdx;
	}

	updateControls(ctrls, v4l2Ctrls);

	return ret;
}

/**
 * \brief Retrieve the v4l2_query_ext_ctrl information for the given control
 * \param[in] id The V4L2 control id
 * \return A pointer to the v4l2_query_ext_ctrl structure for the given
 * control, or a null pointer if not found
 */
const struct v4l2_query_ext_ctrl *V4L2Device::controlInfo(uint32_t id) const
{
	const auto it = controlInfo_.find(id);
	if (it == controlInfo_.end())
		return nullptr;

	return &it->second;
}

/**
 * \brief Retrieve the device path in sysfs
 *
 * This function returns the sysfs path to the physical device backing the V4L2
 * device. The path is guaranteed to be an absolute path, without any symbolic
 * link.
 *
 * It includes the sysfs mount point prefix
 *
 * \return The device path in sysfs
 */
std::string V4L2Device::devicePath() const
{
	std::string devicePath = sysfs::charDevPath(deviceNode_) + "/device";

	char *realPath = realpath(devicePath.c_str(), nullptr);
	if (!realPath) {
		LOG(V4L2, Fatal)
			<< "Can not resolve device path for " << devicePath;
		return {};
	}

	std::string path{ realPath };
	free(realPath);

	return path;
}

/**
 * \brief Enable or disable frame start event notification
 * \param[in] enable True to enable frame start events, false to disable them
 *
 * This function enables or disables generation of frame start events. Once
 * enabled, the events are signalled through the frameStart signal.
 *
 * \return 0 on success, a negative error code otherwise
 */
int V4L2Device::setFrameStartEnabled(bool enable)
{
	if (frameStartEnabled_ == enable)
		return 0;

	struct v4l2_event_subscription event{};
	event.type = V4L2_EVENT_FRAME_SYNC;

	unsigned long request = enable ? VIDIOC_SUBSCRIBE_EVENT
			      : VIDIOC_UNSUBSCRIBE_EVENT;
	int ret = ioctl(request, &event);
	if (enable && ret)
		return ret;

	fdEventNotifier_->setEnabled(enable);
	frameStartEnabled_ = enable;

	return ret;
}

/**
 * \var V4L2Device::frameStart
 * \brief A Signal emitted when capture of a frame has started
 */

/**
 * \brief Perform an IOCTL system call on the device node
 * \param[in] request The IOCTL request code
 * \param[in] argp A pointer to the IOCTL argument
 * \return 0 on success or a negative error code otherwise
 */
int V4L2Device::ioctl(unsigned long request, void *argp)
{
	/*
	 * Printing out an error message is usually better performed
	 * in the caller, which can provide more context.
	 */
	if (::ioctl(fd_.get(), request, argp) < 0)
		return -errno;

	return 0;
}

/**
 * \fn V4L2Device::deviceNode()
 * \brief Retrieve the device node path
 * \return The device node path
 */

/**
 * \fn V4L2Device::fd()
 * \brief Retrieve the V4L2 device file descriptor
 * \return The V4L2 device file descriptor, -1 if the device node is not open
 */

/**
 * \brief Retrieve the libcamera control type associated with the V4L2 control
 * \param[in] ctrlType The V4L2 control type
 * \return The ControlType associated to \a ctrlType
 */
ControlType V4L2Device::v4l2CtrlType(uint32_t ctrlType)
{
	switch (ctrlType) {
	case V4L2_CTRL_TYPE_U8:
		return ControlTypeByte;

	case V4L2_CTRL_TYPE_BOOLEAN:
		return ControlTypeBool;

	case V4L2_CTRL_TYPE_INTEGER:
		return ControlTypeInteger32;

	case V4L2_CTRL_TYPE_INTEGER64:
		return ControlTypeInteger64;

	case V4L2_CTRL_TYPE_MENU:
	case V4L2_CTRL_TYPE_BUTTON:
	case V4L2_CTRL_TYPE_BITMASK:
	case V4L2_CTRL_TYPE_INTEGER_MENU:
		/*
		 * More precise types may be needed, for now use a 32-bit
		 * integer type.
		 */
		return ControlTypeInteger32;

	default:
		return ControlTypeNone;
	}
}

/**
 * \brief Create a ControlId for a V4L2 control
 * \param[in] ctrl The v4l2_query_ext_ctrl that represents a V4L2 control
 * \return A ControlId associated to \a ctrl
 */
std::unique_ptr<ControlId> V4L2Device::v4l2ControlId(const v4l2_query_ext_ctrl &ctrl)
{
	const size_t len = strnlen(ctrl.name, sizeof(ctrl.name));
	const std::string name(static_cast<const char *>(ctrl.name), len);
	const ControlType type = v4l2CtrlType(ctrl.type);

	return std::make_unique<ControlId>(ctrl.id, name, type);
}

/**
 * \brief Create a ControlInfo for a V4L2 control
 * \param[in] ctrl The v4l2_query_ext_ctrl that represents a V4L2 control
 * \return A ControlInfo that represents \a ctrl
 */
std::optional<ControlInfo> V4L2Device::v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl)
{
	switch (ctrl.type) {
	case V4L2_CTRL_TYPE_U8:
		return ControlInfo(static_cast<uint8_t>(ctrl.minimum),
				   static_cast<uint8_t>(ctrl.maximum),
				   static_cast<uint8_t>(ctrl.default_value));

	case V4L2_CTRL_TYPE_BOOLEAN:
		return ControlInfo(static_cast<bool>(ctrl.minimum),
				   static_cast<bool>(ctrl.maximum),
				   static_cast<bool>(ctrl.default_value));

	case V4L2_CTRL_TYPE_INTEGER64:
		return ControlInfo(static_cast<int64_t>(ctrl.minimum),
				   static_cast<int64_t>(ctrl.maximum),
				   static_cast<int64_t>(ctrl.default_value));

	case V4L2_CTRL_TYPE_INTEGER_MENU:
	case V4L2_CTRL_TYPE_MENU:
		return v4l2MenuControlInfo(ctrl);

	default:
		return ControlInfo(static_cast<int32_t>(ctrl.minimum),
				   static_cast<int32_t>(ctrl.maximum),
				   static_cast<int32_t>(ctrl.default_value));
	}
}

/**
 * \brief Create ControlInfo for a V4L2 menu control
 * \param[in] ctrl The v4l2_query_ext_ctrl that represents a V4L2 menu control
 *
 * The created ControlInfo contains indices acquired by VIDIOC_QUERYMENU.
 *
 * \return A ControlInfo that represents \a ctrl
 */
std::optional<ControlInfo> V4L2Device::v4l2MenuControlInfo(const struct v4l2_query_ext_ctrl &ctrl)
{
	std::vector<ControlValue> indices;
	struct v4l2_querymenu menu = {};
	menu.id = ctrl.id;

	if (ctrl.minimum < 0)
		return std::nullopt;

	for (int32_t index = ctrl.minimum; index <= ctrl.maximum; ++index) {
		menu.index = index;
		if (ioctl(VIDIOC_QUERYMENU, &menu) != 0)
			continue;

		indices.push_back(index);
	}

	/*
	 * Some faulty UVC devices are known to return an empty menu control.
	 * Controls without a menu option can not be set, or read, so they are
	 * not exposed.
	 */
	if (indices.size() == 0)
		return std::nullopt;

	return ControlInfo(indices,
			   ControlValue(static_cast<int32_t>(ctrl.default_value)));
}

/*
 * \brief List and store information about all controls supported by the
 * V4L2 device
 */
void V4L2Device::listControls()
{
	ControlInfoMap::Map ctrls;
	struct v4l2_query_ext_ctrl ctrl = {};

	while (1) {
		ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL |
			   V4L2_CTRL_FLAG_NEXT_COMPOUND;
		if (ioctl(VIDIOC_QUERY_EXT_CTRL, &ctrl))
			break;

		if (ctrl.type == V4L2_CTRL_TYPE_CTRL_CLASS ||
		    ctrl.flags & V4L2_CTRL_FLAG_DISABLED)
			continue;

		switch (ctrl.type) {
		case V4L2_CTRL_TYPE_INTEGER:
		case V4L2_CTRL_TYPE_BOOLEAN:
		case V4L2_CTRL_TYPE_MENU:
		case V4L2_CTRL_TYPE_BUTTON:
		case V4L2_CTRL_TYPE_INTEGER64:
		case V4L2_CTRL_TYPE_BITMASK:
		case V4L2_CTRL_TYPE_INTEGER_MENU:
		case V4L2_CTRL_TYPE_U8:
			break;
		/* \todo Support other control types. */
		default:
			LOG(V4L2, Debug)
				<< "Control " << utils::hex(ctrl.id)
				<< " has unsupported type " << ctrl.type;
			continue;
		}

		LOG(V4L2, Debug) << "Control: " << ctrl.name
				 << " (" << utils::hex(ctrl.id) << ")";

		controlIds_.emplace_back(v4l2ControlId(ctrl));
		controlIdMap_[ctrl.id] = controlIds_.back().get();
		controlInfo_.emplace(ctrl.id, ctrl);

		std::optional<ControlInfo> info = v4l2ControlInfo(ctrl);

		if (!info) {
			LOG(V4L2, Error)
				<< "Control " << ctrl.name
				<< " cannot be registered";

			continue;
		}

		ctrls.emplace(controlIds_.back().get(), *info);
	}

	controls_ = ControlInfoMap(std::move(ctrls), controlIdMap_);
}

/**
* \brief Update the information for all device controls
 *
 * The V4L2Device class caches information about all controls supported by the
 * device and exposes it through the controls() and controlInfo() functions.
 * Control information may change at runtime, for instance when formats on a
 * subdev are modified. When this occurs, this function can be used to refresh
 * control information. The information is refreshed in-place, all pointers to
 * v4l2_query_ext_ctrl instances previously returned by controlInfo() and
 * iterators to the ControlInfoMap returned by controls() remain valid.
 *
 * Note that control information isn't refreshed automatically is it may be an
 * expensive operation. The V4L2Device users are responsible for calling this
 * function when required, based on their usage pattern of the class.
 */
void V4L2Device::updateControlInfo()
{
	for (auto &[controlId, info] : controls_) {
		unsigned int id = controlId->id();

		/*
		 * Assume controlInfo_ has a corresponding entry, as it has been
		 * generated by listControls().
		 */
		struct v4l2_query_ext_ctrl &ctrl = controlInfo_[id];

		if (ioctl(VIDIOC_QUERY_EXT_CTRL, &ctrl)) {
			LOG(V4L2, Debug)
				<< "Could not refresh control "
				<< utils::hex(id);
			continue;
		}

		info = *v4l2ControlInfo(ctrl);
	}
}

/*
 * \brief Update the value of the first \a count V4L2 controls in \a ctrls using
 * values in \a v4l2Ctrls
 * \param[inout] ctrls List of V4L2 controls to update
 * \param[in] v4l2Ctrls List of V4L2 extended controls as returned by the driver
 */
void V4L2Device::updateControls(ControlList *ctrls,
				Span<const v4l2_ext_control> v4l2Ctrls)
{
	for (const v4l2_ext_control &v4l2Ctrl : v4l2Ctrls) {
		const unsigned int id = v4l2Ctrl.id;

		ControlValue value = ctrls->get(id);
		if (value.isArray()) {
			/*
			 * No action required, the VIDIOC_[GS]_EXT_CTRLS ioctl
			 * accessed the ControlValue storage directly for array
			 * controls.
			 */
			continue;
		}

		const auto iter = controls_.find(id);
		ASSERT(iter != controls_.end());

		switch (iter->first->type()) {
		case ControlTypeInteger64:
			value.set<int64_t>(v4l2Ctrl.value64);
			break;

		default:
			/*
			 * Note: this catches the ControlTypeInteger32 case.
			 *
			 * \todo To be changed when support for string controls
			 * will be added.
			 */
			value.set<int32_t>(v4l2Ctrl.value);
			break;
		}

		ctrls->set(id, value);
	}
}

/**
 * \brief Slot to handle V4L2 events from the V4L2 device
 *
 * When this slot is called, a V4L2 event is available to be dequeued from the
 * device.
 */
void V4L2Device::eventAvailable()
{
	struct v4l2_event event{};
	int ret = ioctl(VIDIOC_DQEVENT, &event);
	if (ret < 0) {
		LOG(V4L2, Error)
			<< "Failed to dequeue event, disabling event notifier";
		fdEventNotifier_->setEnabled(false);
		return;
	}

	if (event.type != V4L2_EVENT_FRAME_SYNC) {
		LOG(V4L2, Error)
			<< "Spurious event (" << event.type
			<< "), disabling event notifier";
		fdEventNotifier_->setEnabled(false);
		return;
	}

	frameStart.emit(event.u.frame_sync.frame_sequence);
}

static const std::map<uint32_t, ColorSpace> v4l2ToColorSpace = {
	{ V4L2_COLORSPACE_RAW, ColorSpace::Raw },
	{ V4L2_COLORSPACE_SRGB, {
		ColorSpace::Primaries::Rec709,
		ColorSpace::TransferFunction::Srgb,
		ColorSpace::YcbcrEncoding::Rec601,
		ColorSpace::Range::Limited } },
	{ V4L2_COLORSPACE_JPEG, ColorSpace::Sycc },
	{ V4L2_COLORSPACE_SMPTE170M, ColorSpace::Smpte170m },
	{ V4L2_COLORSPACE_REC709, ColorSpace::Rec709 },
	{ V4L2_COLORSPACE_BT2020, ColorSpace::Rec2020 },
};

static const std::map<uint32_t, ColorSpace::TransferFunction> v4l2ToTransferFunction = {
	{ V4L2_XFER_FUNC_NONE, ColorSpace::TransferFunction::Linear },
	{ V4L2_XFER_FUNC_SRGB, ColorSpace::TransferFunction::Srgb },
	{ V4L2_XFER_FUNC_709, ColorSpace::TransferFunction::Rec709 },
};

static const std::map<uint32_t, ColorSpace::YcbcrEncoding> v4l2ToYcbcrEncoding = {
	{ V4L2_YCBCR_ENC_601, ColorSpace::YcbcrEncoding::Rec601 },
	{ V4L2_YCBCR_ENC_709, ColorSpace::YcbcrEncoding::Rec709 },
	{ V4L2_YCBCR_ENC_BT2020, ColorSpace::YcbcrEncoding::Rec2020 },
};

static const std::map<uint32_t, ColorSpace::Range> v4l2ToRange = {
	{ V4L2_QUANTIZATION_FULL_RANGE, ColorSpace::Range::Full },
	{ V4L2_QUANTIZATION_LIM_RANGE, ColorSpace::Range::Limited },
};

static const std::vector<std::pair<ColorSpace, v4l2_colorspace>> colorSpaceToV4l2 = {
	{ ColorSpace::Raw, V4L2_COLORSPACE_RAW },
	{ ColorSpace::Sycc, V4L2_COLORSPACE_JPEG },
	{ ColorSpace::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
	{ ColorSpace::Rec709, V4L2_COLORSPACE_REC709 },
	{ ColorSpace::Rec2020, V4L2_COLORSPACE_BT2020 },
};

static const std::map<ColorSpace::Primaries, v4l2_colorspace> primariesToV4l2 = {
	{ ColorSpace::Primaries::Raw, V4L2_COLORSPACE_RAW },
	{ ColorSpace::Primaries::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
	{ ColorSpace::Primaries::Rec709, V4L2_COLORSPACE_REC709 },
	{ ColorSpace::Primaries::Rec2020, V4L2_COLORSPACE_BT2020 },
};

static const std::map<ColorSpace::TransferFunction, v4l2_xfer_func> transferFunctionToV4l2 = {
	{ ColorSpace::TransferFunction::Linear, V4L2_XFER_FUNC_NONE },
	{ ColorSpace::TransferFunction::Srgb, V4L2_XFER_FUNC_SRGB },
	{ ColorSpace::TransferFunction::Rec709, V4L2_XFER_FUNC_709 },
};

static const std::map<ColorSpace::YcbcrEncoding, v4l2_ycbcr_encoding> ycbcrEncodingToV4l2 = {
	/* V4L2 has no "none" encoding. */
	{ ColorSpace::YcbcrEncoding::None, V4L2_YCBCR_ENC_DEFAULT },
	{ ColorSpace::YcbcrEncoding::Rec601, V4L2_YCBCR_ENC_601 },
	{ ColorSpace::YcbcrEncoding::Rec709, V4L2_YCBCR_ENC_709 },
	{ ColorSpace::YcbcrEncoding::Rec2020, V4L2_YCBCR_ENC_BT2020 },
};

static const std::map<ColorSpace::Range, v4l2_quantization> rangeToV4l2 = {
	{ ColorSpace::Range::Full, V4L2_QUANTIZATION_FULL_RANGE },
	{ ColorSpace::Range::Limited, V4L2_QUANTIZATION_LIM_RANGE },
};

/**
 * \brief Convert the color space fields in a V4L2 format to a ColorSpace
 * \param[in] v4l2Format A V4L2 format containing color space information
 * \param[in] colourEncoding Type of colour encoding
 *
 * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
 * V4L2 format structure are converted to a corresponding ColorSpace.
 *
 * If any V4L2 fields are not recognised then we return an "unset"
 * color space.
 *
 * \return The ColorSpace corresponding to the input V4L2 format
 * \retval std::nullopt One or more V4L2 color space fields were not recognised
 */
template<typename T>
std::optional<ColorSpace> V4L2Device::toColorSpace(const T &v4l2Format,
						   PixelFormatInfo::ColourEncoding colourEncoding)
{
	auto itColor = v4l2ToColorSpace.find(v4l2Format.colorspace);
	if (itColor == v4l2ToColorSpace.end())
		return std::nullopt;

	/* This sets all the color space fields to the correct "default" values. */
	ColorSpace colorSpace = itColor->second;

	if (v4l2Format.xfer_func != V4L2_XFER_FUNC_DEFAULT) {
		auto itTransfer = v4l2ToTransferFunction.find(v4l2Format.xfer_func);
		if (itTransfer == v4l2ToTransferFunction.end())
			return std::nullopt;

		colorSpace.transferFunction = itTransfer->second;
	}

	if (v4l2Format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT) {
		auto itYcbcrEncoding = v4l2ToYcbcrEncoding.find(v4l2Format.ycbcr_enc);
		if (itYcbcrEncoding == v4l2ToYcbcrEncoding.end())
			return std::nullopt;

		colorSpace.ycbcrEncoding = itYcbcrEncoding->second;

		/*
		 * V4L2 has no "none" encoding, override the value returned by
		 * the kernel for non-YUV formats as YCbCr encoding isn't
		 * applicable in that case.
		 */
		if (colourEncoding != PixelFormatInfo::ColourEncodingYUV)
			colorSpace.ycbcrEncoding = ColorSpace::YcbcrEncoding::None;
	}

	if (v4l2Format.quantization != V4L2_QUANTIZATION_DEFAULT) {
		auto itRange = v4l2ToRange.find(v4l2Format.quantization);
		if (itRange == v4l2ToRange.end())
			return std::nullopt;

		colorSpace.range = itRange->second;

		/*
		 * "Limited" quantization range is only meant for YUV formats.
		 * Override the range to "Full" for all other formats.
		 */
		if (colourEncoding != PixelFormatInfo::ColourEncodingYUV)
			colorSpace.range = ColorSpace::Range::Full;
	}

	return colorSpace;
}

template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format &,
							    PixelFormatInfo::ColourEncoding);
template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format_mplane &,
							    PixelFormatInfo::ColourEncoding);
template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_mbus_framefmt &,
							    PixelFormatInfo::ColourEncoding);

/**
 * \brief Fill in the color space fields of a V4L2 format from a ColorSpace
 * \param[in] colorSpace The ColorSpace to be converted
 * \param[out] v4l2Format A V4L2 format containing color space information
 *
 * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
 * V4L2 format structure are filled in from a corresponding ColorSpace.
 *
 * An error is returned if any of the V4L2 fields do not support the
 * value given in the ColorSpace. Such fields are set to the V4L2
 * "default" values, but all other fields are still filled in where
 * possible.
 *
 * If the color space is completely unset, "default" V4L2 values are used
 * everywhere, so a driver would then choose its preferred color space.
 *
 * \return 0 on success or a negative error code otherwise
 * \retval -EINVAL The ColorSpace does not have a representation using V4L2 enums
 */
template<typename T>
int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format)
{
	v4l2Format.colorspace = V4L2_COLORSPACE_DEFAULT;
	v4l2Format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
	v4l2Format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
	v4l2Format.quantization = V4L2_QUANTIZATION_DEFAULT;

	if (!colorSpace)
		return 0;

	auto itColor = std::find_if(colorSpaceToV4l2.begin(), colorSpaceToV4l2.end(),
				    [&colorSpace](const auto &item) {
					    return colorSpace == item.first;
				    });
	if (itColor != colorSpaceToV4l2.end()) {
		v4l2Format.colorspace = itColor->second;
		/* Leaving all the other fields as "default" should be fine. */
		return 0;
	}

	/*
	 * If the colorSpace doesn't precisely match a standard color space,
	 * then we must choose a V4L2 colorspace with matching primaries.
	 */
	int ret = 0;

	auto itPrimaries = primariesToV4l2.find(colorSpace->primaries);
	if (itPrimaries != primariesToV4l2.end()) {
		v4l2Format.colorspace = itPrimaries->second;
	} else {
		libcamera::LOG(V4L2, Warning)
			<< "Unrecognised primaries in "
			<< ColorSpace::toString(colorSpace);
		ret = -EINVAL;
	}

	auto itTransfer = transferFunctionToV4l2.find(colorSpace->transferFunction);
	if (itTransfer != transferFunctionToV4l2.end()) {
		v4l2Format.xfer_func = itTransfer->second;
	} else {
		libcamera::LOG(V4L2, Warning)
			<< "Unrecognised transfer function in "
			<< ColorSpace::toString(colorSpace);
		ret = -EINVAL;
	}

	auto itYcbcrEncoding = ycbcrEncodingToV4l2.find(colorSpace->ycbcrEncoding);
	if (itYcbcrEncoding != ycbcrEncodingToV4l2.end()) {
		v4l2Format.ycbcr_enc = itYcbcrEncoding->second;
	} else {
		libcamera::LOG(V4L2, Warning)
			<< "Unrecognised YCbCr encoding in "
			<< ColorSpace::toString(colorSpace);
		ret = -EINVAL;
	}

	auto itRange = rangeToV4l2.find(colorSpace->range);
	if (itRange != rangeToV4l2.end()) {
		v4l2Format.quantization = itRange->second;
	} else {
		libcamera::LOG(V4L2, Warning)
			<< "Unrecognised quantization in "
			<< ColorSpace::toString(colorSpace);
		ret = -EINVAL;
	}

	return ret;
}

template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format &);
template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format_mplane &);
template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_mbus_framefmt &);

} /* namespace libcamera */
Age	Commit message (Collapse)	Author
2021-09-07	libcamera: formats: Add planeSize() helpers to PixelFormatInfo	Laurent Pinchart
	Add two helpers functions to the PixelFormatInfo class to compute the byte size of a given plane, taking the frame size, the stride, the alignment constraints and the vertical subsampling into account. Use the new functions through the code base to replace manual implementations. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-09-06	android: Cleanup libcamera namespace usage	Umang Jain
	Usually .cpp files are equipped with using namespace libcamera; Hence, it is unnecessary mentioning the explicit namespace of libcamera at certain places. While at it, a small typo in a comment was noticed and fixed as part of this patch. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-08-31	android: generic_camera_buffer: Fix bufferLength_ initialization	Laurent Pinchart
	The bufferLength_ member variabled is checked to have a positive value before being used, to catch usage before the variable is set. The variable is initialized to zero at construction time, which renders the checks useless. Fix this by initializing the variable to -1 at construction time. Fixes: c5e2ed7806be ("android: camera_buffer: Map buffer in the first plane() call") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2021-08-30	libcamera: mapped_framebuffer: Return plane begin address by ↵	Hirokazu Honda
	MappedBuffer::maps() MappedBuffer::maps() returns std::vector<MappedBuffer::Plane>. Plane has the address, but the address points the beginning of the buffer containing the plane. This makes the Plane point the beginning of the plane. So MappedBuffer::maps()[i].data() returns the address of i-th plane. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-08-27	android: camera_buffer: Add stride/offset/size function	Hirokazu Honda
	This adds getter functions of stride, offset and size to CameraBuffer interface. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-08-27	android: camera_buffer: Map buffer in the first plane() call	Hirokazu Honda
	CameraBuffer implementation maps a given buffer_handle_t in constructor. Mapping is redundant to only know the plane info like stride and offset. Mapping should be executed later in the first plane() call. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-08-27	android: generic_camera_buffer: Correct buffer mapping	Hirokazu Honda
	buffer_handle_t doesn't provide sufficient info to map a buffer properly. cros::CameraBufferManager enables handling the buffer on ChromeOS, but no way is provided for other platforms. Therefore, we put the assumption that planes are in the same buffer and they are consecutive. This modifies the way of mapping in generic_camera_buffer with the assumption. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-08-10	libcamera: Give MappedFrameBuffer its own implementation	Kieran Bingham
	The MappedFrameBuffer is a convenience feature which sits on top of the FrameBuffer and facilitates mapping it to CPU accessible memory with mmap. This implementation is internal and currently sits in the same internal files as the internal FrameBuffer, thus exposing those internals to users of the MappedFramebuffer implementation. Move the MappedFrameBuffer and MappedBuffer implementation to its own implementation files, and fix the sources throughout to use that accordingly. Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2021-08-06	android: mm: cros_camera_buffer: Fix unused parameter	Hirokazu Honda
	cameraBuffer function in private constructor is unused. Mark it as such. Fixes: 33dd4fab9d39("libcamera: base: class: Don't pass Extensible pointer to Private constructor") Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> 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> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2021-08-03	libcamera: base: class: Don't pass Extensible pointer to Private constructor	Laurent Pinchart
	The Extensible and Extensible::Private classes contain pointers to each other. These pointers are initialized in the respective class's constructor, by passing a pointer to the other class to each constructor. This particular construct reduces the flexibility of the Extensible pattern, as the Private class instance has to be allocated and constructed in the members initializer list of the Extensible class's constructor. It is thus impossible to perform any operation on the Private class between its construction and the construction of the Extensible class, or to subclass the Private class without subclassing the Extensible class. To make the design pattern more flexible, don't pass the pointer to the Extensible class to the Private class's constructor, but initialize the pointer manually in the Extensible class's constructor. This requires a const_cast as the o_ member of the Private class is const. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2021-07-11	libcamera: buffer: Rename buffer.h to framebuffer.h	Laurent Pinchart
	libcamera names header files based on the classes they define. The buffer.h file is an exception. Rename it to framebuffer.h. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2021-06-28	android: mm: cros_camera_buffer: Drop undefined functions	Laurent Pinchart
	The CameraBuffer::Private::planeAddr() functions are declared but not defined (and of course not used). Drop them. Fixes: d8d6a78f223e ("android: Introduce Chromium OS buffer manager") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
2021-06-25	libcamera/base: Move extended base functionality	Kieran Bingham
	Move the functionality for the following components to the new base support library: - BoundMethod - EventDispatcher - EventDispatcherPoll - Log - Message - Object - Signal - Semaphore - Thread - Timer While it would be preferable to see these split to move one component per commit, these components are all interdependent upon each other, which leaves us with one big change performing the move for all of them. Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2021-06-25	android: mm: cros_camera_buffer: Fix wrong indexing in plane()	Hirokazu Honda
	CameraBuffer::plane() should be accessed in zero based index. Fix the wrong indexing in CameraBuffer::plane() in cros_camera_buffer.cpp. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
2021-06-01	android: Fix unused parameter warnings on Chrome OS	Laurent Pinchart
	The Chrome OS-specific code has multiple function parameters that are not used. This results in compilation warnings. Fix them with [[maybe_unused]]. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
2021-05-31	android: Don't rely on indirect inclusion of unistd.h	Laurent Pinchart
	The standard C library close() and lseek() functions require inclusion of the unistd.h header. Include it explicitly where needed instead of relying on indirect inclusion. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Tested-by: Paul Elder <paul.elder@ideasonboard.com>
2021-05-05	src: android: Rectify internal header's #include path	Umang Jain
	libcamera internal headers are not installed system-wide. Hence, any inclusion of internal headers should follow the #include directive form: #include "libcamera/internal/header.h" This was not the case for a few of the class in android HAL. Fix them. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-04-04	android: mm: cros: Fix compilation	Laurent Pinchart
	Commit 7d7879833812 ("android: mm: cros: Handle buffer registration failure") mistakenly tried to initialize the CameraBuffer::Private registered member variable instead of registered_. This reults in a compilation failure. Fix it. Fixes: 7d7879833812 ("android: mm: cros: Handle buffer registration failure") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-04-04	android: mm: cros: Handle buffer registration failure	Hirokazu Honda
	cros::CameraBufferManager::Register() fails if a buffer handle is invalid. We should mark CameraBuffer as invalid on the failure of Register(). While the cros::CameraBufferManager Unlock() and Deregister() functions should be able to handle buffers that haven't been locked and registered, this isn't an API guarantee, and errors will be logged. Avoid this by skipping unlocking and unregistration of buffers that haven't been locked or registered. Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2021-03-03	android: Introduce Chromium OS buffer manager	Jacopo Mondi
	Introduce the CameraBuffer backend for the Chromium OS operating system and the associated meson option. The Chromium OS CameraBuffer implementation uses the cros::CameraBufferManager class to perform mapping of 1 plane and multiplane buffers and to retrieve size information. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: mm: Provide helper macro for PIMPL	Jacopo Mondi
	Each memory backend has to declare a CameraBuffer class implementation that bridges the API calls to each CameraBuffer::Private implementation. As the code is likely the same for most (if not all) backends, provide a convenience macro that expands to the CameraBuffer class declaration. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: camera_buffer: Add method to get the JPEG blob size	Jacopo Mondi
	To maintain compatibility with platforms that do not provide a memory backend implementation add a method to be return the size of the buffer used for JPEG encoding capped to a maximum size. Platforms that implement a memory backend will always calculate the correct buffer size. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: post_processor: Use CameraBuffer API	Jacopo Mondi
	Use the newly introduced CameraBuffer class as the type for the destination buffer in the PostProcessor class hierarchy in place of the libcamera::MappedFrameBuffer one and use its API to retrieve the length and the location of the CameraBuffer plane allocated for JPEG post-processing. Remove all the assumption on the underlying memory storage and only go through the CameraBuffer API when dealing with memory buffers. To do so rework the Encoder interface to use a raw pointer and an explicit size to remove access to the Span<uint8_t> maps that serve as memory storage for the current implementation but might not be ideal for other memory backend. Now that the whole PostProcessor hierarchy has been converted to use the CameraBuffer API remove libcamera::MappedBuffer as base class of the CameraBuffer interface and only reply on its interface. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: camera_buffer: Implement libcamera::Extensible	Jacopo Mondi
	In order to prepare to support more memory backends, make the CameraBuffer class implement the PIMPL (pointer-to-implementation) pattern by inheriting from the libcamera::Extensible class. Temporary maintain libcamera::MappedBuffer as the CameraBuffer base class to maintain compatibility of the CameraStream::process() interface that requires a MappedBuffer * as second argument and will be converted to use a CameraBuffer in the next patch. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: camera_buffer: Drop 'const' from buffer_handle_t	Jacopo Mondi
	The buffer_handle_t type is defined as 'const native_handle_t*'. Drop the 'const' specifier from the parameter of the CameraBuffer class constructor and in the Android generic memory backend. Also rename 'camera3buffer' in 'camera3Buffer' to comply with the coding style guidelines. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
2021-03-03	android: Introduce CameraBuffer interface	Jacopo Mondi
	In order to provide support for different memory backends, move the MappedCamera3Buffer class definition outside of the CameraDevice class to its own file and rename it in CameraBuffer. The interface defined in camera_buffer.h will be implemented by different backends that will be placed in the src/android/mm subdirectory. Provide a first implementation for the 'generic android' backend which matches the existing one. Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>