cdc2620549
The V4L2 requests API provides support to atomically tie controls to a set of buffers. This is especially common for m2m devices. Such a request is represented by an fd that is allocated via MEDIA_IOC_REQUEST_ALLOC and then passed to the various V4L2 functions. Implement a V4L2Request class to wrap such an fd and add the corresponding utility functions. Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
129 lines
2.5 KiB
C++
129 lines
2.5 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
|
|
/*
|
|
* Copyright (C) 2025, Ideas On Board
|
|
*
|
|
* V4L2 Request
|
|
*/
|
|
|
|
#include "libcamera/internal/v4l2_request.h"
|
|
|
|
#include <fcntl.h>
|
|
#include <stdlib.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/syscall.h>
|
|
#include <unistd.h>
|
|
|
|
#include <linux/media.h>
|
|
|
|
#include <libcamera/base/event_notifier.h>
|
|
#include <libcamera/base/log.h>
|
|
|
|
/**
|
|
* \file v4l2_request.h
|
|
* \brief V4L2 Request
|
|
*/
|
|
|
|
namespace libcamera {
|
|
|
|
LOG_DECLARE_CATEGORY(V4L2)
|
|
|
|
/**
|
|
* \class V4L2Request
|
|
* \brief V4L2Request object and API
|
|
*
|
|
* The V4L2Request class wraps a V4L2 request fd and provides some convenience
|
|
* functions to handle request.
|
|
*
|
|
* It is usually constructed by calling \a MediaDevice::allocateRequests().
|
|
*
|
|
* A request can then be passed to the V4L2Device::setControls(),
|
|
* V4L2Device::getControls() and V4L2VideoDevice::queueBuffer().
|
|
*/
|
|
|
|
/**
|
|
* \brief Construct a V4L2Request
|
|
* \param[in] fd The request fd
|
|
*/
|
|
V4L2Request::V4L2Request(UniqueFD &&fd)
|
|
: fd_(std::move(fd)), fdNotifier_(fd_.get(), EventNotifier::Exception)
|
|
{
|
|
if (!fd_.isValid())
|
|
return;
|
|
|
|
fdNotifier_.activated.connect(this, &V4L2Request::requestReady);
|
|
fdNotifier_.setEnabled(false);
|
|
}
|
|
|
|
/**
|
|
* \fn V4L2Request::isValid()
|
|
* \brief Check if the request is valid
|
|
*
|
|
* Checks if the underlying fd is valid.
|
|
*
|
|
* \return True if the request is valid, false otherwise
|
|
*/
|
|
|
|
/**
|
|
* \fn V4L2Request::fd()
|
|
* \brief Get the file descriptor
|
|
*
|
|
* \return The file descriptor wrapped by this V4L2Request
|
|
*/
|
|
|
|
/**
|
|
* \var V4L2Request::requestDone
|
|
* \brief Signal that is emitted when the request is done
|
|
*/
|
|
|
|
/**
|
|
* \brief Reinit the request
|
|
*
|
|
* Calls MEDIA_REQUEST_IOC_REINIT on the request fd.
|
|
*
|
|
* \return 0 on success or a negative error code otherwise
|
|
*/
|
|
int V4L2Request::reinit()
|
|
{
|
|
fdNotifier_.setEnabled(false);
|
|
|
|
if (::ioctl(fd_.get(), MEDIA_REQUEST_IOC_REINIT) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* \brief Queue the request
|
|
*
|
|
* Calls MEDIA_REQUEST_IOC_QUEUE on the request fd.
|
|
*
|
|
* \return 0 on success or a negative error code otherwise
|
|
*/
|
|
int V4L2Request::queue()
|
|
{
|
|
if (::ioctl(fd_.get(), MEDIA_REQUEST_IOC_QUEUE) < 0)
|
|
return -errno;
|
|
|
|
fdNotifier_.setEnabled(true);
|
|
|
|
return 0;
|
|
}
|
|
|
|
std::string V4L2Request::logPrefix() const
|
|
{
|
|
return "Request [" + std::to_string(fd()) + "]";
|
|
}
|
|
|
|
/**
|
|
* \brief Slot to handle request done events
|
|
*
|
|
* When this slot is called, the request is done and the requestDone will be
|
|
* emitted.
|
|
*/
|
|
void V4L2Request::requestReady()
|
|
{
|
|
requestDone.emit(this);
|
|
}
|
|
|
|
} /* namespace libcamera */
|