/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Copyright (C) 2018-2019, Google Inc. * * media_device_print_test.cpp - Print out media devices */ #include #include #include #include #include "libcamera/internal/media_device.h" #include "test.h" using namespace libcamera; using namespace std; /* * MediaDevicePrintTest takes all media devices found in the system and print * them out to verify correctness. * * If no accessible media device is found, the test is skipped. */ class MediaDevicePrintTest : public Test { protected: int init() { return 0; } int run(); void cleanup() {} private: int testMediaDevice(string deviceNode); void printMediaGraph(const MediaDevice &media, ostream &os); void printLinkFlags(const MediaLink *link, ostream &os); void printNode(const MediaPad *pad, ostream &os); }; void MediaDevicePrintTest::printNode(const MediaPad *pad, ostream &os) { const MediaEntity *entity = pad->entity(); os << "\"" << entity->name() << "\"[" << pad->index() << "]"; } void MediaDevicePrintTest::printLinkFlags(const MediaLink *link, ostream &os) { unsigned int flags = link->flags(); os << " ["; if (flags) { os << (flags & MEDIA_LNK_FL_ENABLED ? "ENABLED," : "") << (flags & MEDIA_LNK_FL_IMMUTABLE ? "IMMUTABLE" : ""); } os << "]\n"; } /* * For each entity in the media graph, printout links directed to its sinks * and source pads. */ void MediaDevicePrintTest::printMediaGraph(const MediaDevice &media, ostream &os) { os << "\n" << media.driver() << " - " << media.deviceNode() << "\n\n"; for (auto const &entity : media.entities()) { os << "\"" << entity->name() << "\"\n"; for (auto const &sink : entity->pads()) { if (!(sink->flags() & MEDIA_PAD_FL_SINK)) continue; os << " [" << sink->index() << "]" << ": Sink\n"; for (auto const &link : sink->links()) { os << "\t"; printNode(sink, os); os << " <- "; printNode(link->source(), os); printLinkFlags(link, os); } os << "\n"; } for (auto const &source : entity->pads()) { if (!(source->flags() & MEDIA_PAD_FL_SOURCE)) continue; os << " [" << source->index() << "]" << ": Source\n"; for (auto const &link : source->links()) { os << "\t"; printNode(source, os); os << " -> "; printNode(link->sink(), os); printLinkFlags(link, os); } os << "\n"; } } os.flush(); } /* Test a single media device. */ int MediaDevicePrintTest::testMediaDevice(const string deviceNode) { MediaDevice dev(deviceNode); int ret; ret = dev.populate(); if (ret) return ret; /* Print out the media graph. */ printMediaGraph(dev, cerr); return 0; } /* Run tests on all media devices. */ #define MAX_MEDIA_DEV 256 int MediaDevicePrintTest::run() { const string deviceNode("/dev/media"); unsigned int i; int ret = 77; /* skip test exit code */ /* * Run the test sequence on all media device found in the * system, if any. */ for (i = 0; i < MAX_MEDIA_DEV; i++) { string mediadev = deviceNode + to_string(i); struct stat pstat = {}; if (stat(mediadev.c_str(), &pstat)) continue; ret = testMediaDevice(mediadev); if (ret) return ret; } return ret; } TEST_REGISTER(MediaDevicePrintTest) c/libcamera/media_device.cpp?id=ef30be09eb0faba6739b4efee450d0c9751c121b'>plain) 
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2018, Google Inc.
 *
 * media_device.cpp - Media device handler
 */

#include "media_device.h"

#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>

#include <string>
#include <vector>

#include <linux/media.h>

#include "log.h"

/**
 * \file media_device.h
 * \brief Provide a representation of a Linux kernel Media Controller device
 * that exposes the full graph topology.
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(MediaDevice)

/**
 * \class MediaDevice
 * \brief The MediaDevice represents a Media Controller device with its full
 * graph of connected objects.
 *
 * A MediaDevice instance is associated with a media controller device node when
 * created, and that association is kept for the lifetime of the MediaDevice
 * instance.
 *
 * The instance is created with an empty media graph. Before performing any
 * other operation, it must be opened with the open() function and the media
 * graph populated by calling populate(). Instances of MediaEntity, MediaPad and
 * MediaLink are created to model the media graph, and stored in a map indexed
 * by object id.
 *
 * The graph is valid once successfully populated, as reported by the valid()
 * function. It can be queried to list all entities(), or entities can be
 * looked up by name with getEntityByName(). The graph can be traversed from
 * entity to entity through pads and links as exposed by the corresponding
 * classes.
 *
 * An open media device will keep an open file handle for the underlying media
 * controller device node. It can be closed at any time with a call to close().
 * This will not invalidate the media graph and all cached media objects remain
 * valid and can be accessed normally. The device can then be later reopened if
 * needed to perform other operations that interact with the device node.
 *
 * Media device can be claimed for exclusive use with acquire(), released with
 * release() and tested with busy(). This mechanism is aimed at pipeline
 * managers to claim media devices they support during enumeration.
 */

/**
 * \brief Construct a MediaDevice
 * \param[in] deviceNode The media device node path
 *
 * Once constructed the media device is invalid, and must be opened and
 * populated with open() and populate() before the media graph can be queried.
 */
MediaDevice::MediaDevice(const std::string &deviceNode)
	: deviceNode_(deviceNode), fd_(-1), valid_(false), acquired_(false)
{
}

MediaDevice::~MediaDevice()
{
	if (fd_ != -1)
		::close(fd_);
	clear();
}

/**
 * \brief Claim a device for exclusive use
 *
 * The device claiming mechanism offers simple media device access arbitration
 * between multiple users. When the media device is created, it is available to
 * all users. Users can query the media graph to determine whether they can
 * support the device and, if they do, claim the device for exclusive use. Other
 * users are then expected to skip over media devices in use as reported by the
 * busy() function.
 *
 * Once claimed the device shall be released by its user when not needed anymore
 * by calling the release() function.
 *
 * Exclusive access is only guaranteed if all users of the media device abide by
 * the device claiming mechanism, as it isn't enforced by the media device
 * itself.
 *
 * \return true if the device was successfully claimed, or false if it was
 * already in use
 * \sa release(), busy()
 */
bool MediaDevice::acquire()
{
	if (acquired_)
		return false;

	acquired_ = true;
	return true;
}

/**
 * \fn MediaDevice::release()
 * \brief Release a device previously claimed for exclusive use
 * \sa acquire(), busy()
 */

/**
 * \fn MediaDevice::busy()
 * \brief Check if a device is in use
 * \return true if the device has been claimed for exclusive use, or false if it
 * is available
 * \sa acquire(), release()
 */

/**
 * \brief Open the media device
 *
 * \return 0 on success or a negative error code otherwise
 * \retval -EBUSY Media device already open
 * \sa close()
 */
int MediaDevice::open()
{
	if (fd_ != -1) {
		LOG(MediaDevice, Error) << "MediaDevice already open";
		return -EBUSY;
	}

	int ret = ::open(deviceNode_.c_str(), O_RDWR);
	if (ret < 0) {
		ret = -errno;
		LOG(MediaDevice, Error)
			<< "Failed to open media device at "
			<< deviceNode_ << ": " << strerror(-ret);
		return ret;
	}
	fd_ = ret;

	return 0;
}

/**
 * \brief Close the media device
 *
 * This function closes the media device node. It does not invalidate the media
 * graph and all cached media objects remain valid and can be accessed normally.
 * Once closed no operation interacting with the media device node can be