/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2018, Google Inc. * * pipeline_handler.cpp - Pipeline handler infrastructure */ #include "libcamera/internal/pipeline_handler.h" #include #include #include #include #include #include #include "libcamera/internal/device_enumerator.h" #include "libcamera/internal/media_device.h" #include "libcamera/internal/tracepoints.h" /** * \file pipeline_handler.h * \brief Create pipelines and cameras from a set of media devices * * Each pipeline supported by libcamera needs to be backed by a pipeline * handler implementation that operate on a set of media devices. The pipeline * handler is responsible for matching the media devices it requires with the * devices present in the system, and once all those devices can be acquired, * create corresponding Camera instances. * * Every subclass of PipelineHandler shall be registered with libcamera using * the REGISTER_PIPELINE_HANDLER() macro. */ namespace libcamera { LOG_DEFINE_CATEGORY(Pipeline) /** * \class CameraData * \brief Base class for platform-specific data associated with a camera * * The CameraData base abstract class represents platform specific-data * a pipeline handler might want to associate with a Camera to access them * at a later time. * * Pipeline handlers are expected to extend this base class with platform * specific implementation, associate instances of the derived classes * using the registerCamera() method, and access them at a later time * with cameraData(). */ /** * \fn CameraData::CameraData(PipelineHandler *pipe) * \brief Construct a CameraData instance for the given pipeline handler * \param[in] pipe The pipeline handler * * The reference to the pipeline handler is stored internally, the caller shall * guarantee that the pointer remains valid as long as the CameraData instance * exists. */ /** * \var CameraData::pipe_ * \brief The pipeline handler related to this CameraData instance * * The pipe_ pointer provides access to the PipelineHandler object that this * instance is related to. It is set when the CameraData instance is created * and remains valid until the instance is destroyed. */ /** * \var CameraData::queuedRequests_ * \brief The list of queued and not yet completed request * * The list of queued request is used to track requests queued in order to * ensure completion of all requests when the pipeline handler is stopped. * * \sa PipelineHandler::queueRequest(), PipelineHandler::stop(), * PipelineHandler::completeRequest() */ /** * \var CameraData::controlInfo_ * \brief The set of controls supported by the camera * * The control information shall be initialised by the pipeline handler when * creating the camera, and shall not be modified afterwards. */ /** * \var CameraData::properties_ * \brief The list of properties supported by the camera * * The list of camera properties shall be initialised by the pipeline handler * when creating the camera, and shall not be modified afterwards. */ /** * \var CameraData::requestSequence_ * \brief The queuing sequence of the request * * When requests are queued, they are given a per-camera sequence number to * facilitate debugging of internal request usage. * * The requestSequence_ tracks the number of requests queued to a camera * over its lifetime. */ /** * \class PipelineHandler * \brief Create and manage cameras based on a set of media devices * * The PipelineHandler matches the media devices provided by a DeviceEnumerator * with the pipelines it supports and creates corresponding Camera devices. * * Pipeline handler instances are reference-counted through std::shared_ptr<>. * They implement std::enable_shared_from_this<> in order to create new * std::shared_ptr<> in code paths originating from member functions of the * PipelineHandler class where only the 'this' pointer is available. */ /** * \brief Construct a PipelineHandler instance * \param[in] manager The camera manager * * In order to honour the std::enable_shared_from_this<> contract, * PipelineHandler instances shall never be constructed manually, but always * through the PipelineHandlerFactory::create() method implemented by the * respective factories. */ PipelineHandler::PipelineHandler(CameraManager *manager) : manager_(manager) { } PipelineHandler::~PipelineHandler() { for (std::shared_ptr media : mediaDevices_) media->release(); } /** * \fn PipelineHandler::match(DeviceEnumerator *enumerator) * \brief Match media devices and create camera instances * \param[in] enumerator The enumerator providing all media devices found in the * system * * This function is the main entry point of the pipeline handler. It is called * by the camera manager with the \a enumerator passed as an argument. It shall * acquire from the \a enumerator all the media devices it needs for a single * pipeline, create one or multiple Camera instances and register them with the * camera manager. * * If all media devices needed by the pipeline handler are found, they must all * be acquired by a call to MediaDevice::acquire(). This function shall then * create the corresponding Camera instances, store them internally, and return * true. Otherwise it shall not acquire any media device (or shall release all * the media devices is has acquired by calling MediaDevice::release()) and * return false. * * If multiple instances of a pipeline are available in the system, the * PipelineHandler class will be instantiated once per instance, and its match() * function called for every instance. Each call shall acquire media devices for * one pipeline instance, until all compatible media devices are exhausted. * * If this function returns true, a new instance of the pipeline handler will * be created and its match() function called. * * \context This function is called from the CameraManager thread. * * \return true if media devices have been acquired and camera instances * created, or false otherwise */ /** * \brief Search and acquire a MediaDevice matching a device pattern * \param[in] enumerator Enumerator containing all media devices in the system * \param[in] dm Device match pattern * * Search the device \a enumerator for an available media device matching the * device match pattern \a dm. Matching media device that have previously been * acquired by MediaDevice::acquire() are not considered. If a match is found, * the media device is acquired and returned. The caller shall not release the * device explicitly, it will be automatically released when the pipeline * handler is destroyed. * * \context This function shall be called from the CameraManager thread. * * \return A pointer to the matching MediaDevice, or nullptr if no match is found */ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator, const DeviceMatch &dm) { std::shared_ptr media = enumerator->search(dm); if (!media) return nullptr; if (!media->acquire()) return nullptr; mediaDevices_.push_back(media); return media.get(); } /** * \brief Lock all media devices acquired by the pipeline * * This method shall not be called from pipeline handler implementation, as the * Camera class handles locking directly. * * \context This function is \threadsafe. * * \return True if the devices could be locked, false otherwise * \sa unlock() * \sa MediaDevice::lock() */ bool PipelineHandler::lock() { for (std::shared_ptr &media : mediaDevices_) { if (!media->lock()) { unlock(); return false; } } return true; } /** * \brief Unlock all media devices acquired by the pipeline * * This method shall not be called from pipeline handler implementation, as the * Camera class handles locking directly. * * \context This function is \threadsafe. * * \sa lock() */ void PipelineHandler::unlock() { for (std::shared_ptr &media : mediaDevices_) media->unlock(); } /** * \brief Retrieve the list of controls for a camera * \param[in] camera The camera * \context This function is \threadsafe. * \return A ControlInfoMap listing the controls support by \a camera */ const ControlInfoMap &PipelineHandler::controls(const Camera *camera) const { const CameraData *data = cameraData(camera); return data->controlInfo_; } /** * \brief Retrieve the list of properties for a camera * \param[in] camera The camera * \return A ControlList of properties supported by \a camera */ const ControlList &PipelineHandler::properties(const Camera *camera) const { const CameraData *data = cameraData(camera); return data->properties_; } /** * \fn PipelineHandler::generateConfiguration() * \brief Generate a camera configuration for a specified camera * \param[in] camera The camera to generate a default configuration for * \param[in] roles A list of stream roles * * Generate a default configuration for the \a camera for a specified list of * stream roles. The caller shall populate the \a roles with the use-cases it * wishes to fetch the default configuration for. The returned configuration * can then be examined by the caller to learn about the selected streams and * their default parameters. * * The intended companion to this is \a configure() which can be used to change * the group of streams parameters. * * \context This function may be called from any thread and shall be * \threadsafe. It shall not modify the state of the \a camera in the pipeline * handler. * * \return A valid CameraConfiguration if the requested roles can be satisfied, * or a null pointer otherwise. The ownership of the returned configuration is * passed to the caller. */ /** * \fn PipelineHandler::configure() * \brief Configure a group of streams for capture * \param[in] camera The camera to configure * \param[in] config The camera configurations to setup * * Configure the specified group of streams for \a camera according to the * configuration specified in \a config. The intended caller of this interface * is the Camera class which will receive configuration to apply from the * application. * * The configuration is guaranteed to have been validated with * CameraConfiguration::validate(). The pipeline handler implementation shall * not perform further validation and may rely on any custom field stored in its * custom CameraConfiguration derived class. * * When configuring the camera the pipeline handler shall associate a Stream * instance to each StreamConfiguration entry in the CameraConfiguration using * the StreamConfiguration::setStream() method. * * \context This function is called from the CameraManager thread. * * \return 0 on success or a negative error code otherwise */ /** * \fn PipelineHandler::exportFrameBuffers() * \brief Allocate and export buffers for \a stream * \param[in] camera The camera * \param[in] stream The stream to allocate buffers for * \param[out] buffers Array of buffers successfully allocated * * This method allocates buffers for the \a stream from the devices associated * with the stream in the corresponding pipeline handler. Those buffers shall be * suitable to be added to a Request for the stream, and shall be mappable to * the CPU through their associated dmabufs with mmap(). * * The method may only be called after the Camera has been configured and before * it gets started, or after it gets stopped. It shall be called only for * streams that are part of the active camera configuration. * * The only intended caller is Camera::exportFrameBuffers(). * * \context This function is called from the CameraManager thread. * * \return The number of allocated buffers on success or a negative error code * otherwise */ /** * \fn PipelineHandler::start() * \brief Start capturing from a group of streams * \param[in] camera The camera to start * \param[in] controls Controls to be applied before starting the Camera * * Start the group of streams that have been configured for capture by * \a configure(). The intended caller of this method is the Camera class which * will in turn be called from the application to indicate that it has * configured the streams and is ready to capture. * * \context This function is called from the CameraManager thread. * * \return 0 on success or a negative error code otherwise */ /** * \fn PipelineHandler::stop() * \brief Stop capturing from all running streams * \param[in] camera The camera to stop * * This method stops capturing and processing requests immediately. All pending * requests are cancelled and complete immediately in an error state. * * \context This function is called from the CameraManager thread. */ /** * \brief Determine if the camera has any requests pending * \param[in] camera The camera to check * * This method determines if there are any requests queued to the pipeline * awaiting processing. * * \return True if there are pending requests, or false otherwise */ bool PipelineHandler::hasPendingRequests(const Camera *camera) const { const CameraData *data = cameraData(camera); return !data->queuedRequests_.empty(); } /** * \fn PipelineHandler::queueRequest() * \brief Queue a request * \param[in] request The request to queue * * This method queues a capture request to the pipeline handler for processing. * The request is first added to the internal list of queued requests, and * then passed to the pipeline handler with a call to queueRequestDevice(). * If the pipeline handler fails in queuing the request to the hardware the * request is cancelled. * * Keeping track of queued requests ensures automatic completion of all requests * when the pipeline handler is stopped with stop(). Request completion shall be * signalled by the pipeline handler using the completeRequest() method. * * \context This function is called from the CameraManager thread. */ void PipelineHandler::queueRequest(Request *request) { LIBCAMERA_TRACEPOINT(request_queue, request); Camera *camera = request->camera_; CameraData *data = cameraData(camera); data->queuedRequests_.push_back(request); request->sequence_ = data->requestSequence_++; int ret = queueRequestDevice(camera, request); if (ret) { request->cancel(); completeRequest(request); } } /** * \fn PipelineHandler::queueRequestDevice() * \brief Queue a request to the device * \param[in] camera The camera to queue the request to * \param[in] request The request to queue * * This method queues a capture request to the device for processing. The * request contains a set of buffers associated with streams and a set of * parameters. The pipeline handler shall program the device to ensure that the * parameters will be applied to the frames captured in the buffers provided in * the request. * * \context This function is called from the CameraManager thread. * * \return 0 on success or a negative error code otherwise */ /** * \brief Complete a buffer for a request * \param[in] request The request the buffer belongs to * \param[in] buffer The buffer that has completed * * This method shall be called by pipeline handlers to signal completion of the * \a buffer part of the \a request. It notifies applications of buffer * completion and updates the request's internal buffer tracking. The request * is not completed automatically when the last buffer completes to give * pipeline handlers a chance to perform any operation that may still be * needed. They shall complete requests explicitly with completeRequest(). * * \context This function shall be called from the CameraManager thread. * * \return True if all buffers contained in the request have completed, false * otherwise */ bool PipelineHandler::completeBuffer(Request *request, FrameBuffer *buffer) { Camera *camera = request->camera_; camera->bufferCompleted.emit(request, buffer); return request->completeBuffer(buffer); } /** * \brief Signal request completion * \param[in] request The request that has completed * * The pipeline handler shall call this method to notify the \a camera that the * request has completed. The request is no longer managed by the pipeline * handler and shall not be accessed once this method returns. * * This method ensures that requests will be returned to the application in * submission order, the pipeline handler may call it on any complete request * without any ordering constraint. * * \context This function shall be called from the CameraManager thread. */ void PipelineHandler::completeRequest(Request *request) { Camera *camera = request->camera_; request->complete(); CameraData *data = cameraData(camera); while (!data->queuedRequests_.empty()) { Request *req = data->queuedRequests_.front(); if (req->status() == Request::RequestPending) break; ASSERT(!req->hasPendingBuffers()); data->queuedRequests_.pop_front(); camera->requestComplete(req); } } /** * \brief Register a camera to the camera manager and pipeline handler * \param[in] camera The camera to be added * \param[in] data Pipeline-specific data for the camera * * This method is called by pipeline handlers to register the cameras they * handle with the camera manager. It associates the pipeline-specific \a data * with the camera, for later retrieval with cameraData(). Ownership of \a data * is transferred to the PipelineHandler. * * \context This function shall be called from the CameraManager thread. */ void PipelineHandler::registerCamera(std::shared_ptr camera, std::unique_ptr data) { cameraData_[camera.get()] = std::move(data); cameras_.push_back(camera); if (mediaDevices_.empty()) LOG(Pipeline, Fatal) << "Registering camera with no media devices!"; /* * Walk the entity list and map the devnums of all capture video nodes * to the camera. */ std::vector devnums; for (const std::shared_ptr &media : mediaDevices_) { for (const MediaEntity *entity : media->entities()) { if (entity->pads().size() == 1 && (entity->pads()[0]->flags() & MEDIA_PAD_FL_SINK) && entity->function() == MEDIA_ENT_F_IO_V4L) { devnums.push_back(makedev(entity->deviceMajor(), entity->deviceMinor())); } } } manager_->addCamera(std::move(camera), devnums); } /** * \brief Enable hotplug handling for a media device * \param[in] media The media device * * This function enables hotplug handling, and especially hot-unplug handling, * of the \a media device. It shall be called by pipeline handlers for all the * media devices that can be disconnected. * * When a media device passed to this function is later unplugged, the pipeline * handler gets notified and automatically disconnects all the cameras it has * registered without requiring any manual intervention. */ void PipelineHandler::hotplugMediaDevice(MediaDevice *media) { media->disconnected.connect(this, &PipelineHandler::mediaDeviceDisconnected); } /** * \brief Slot for the MediaDevice disconnected signal */ void PipelineHandler::mediaDeviceDisconnected(MediaDevice *media) { media->disconnected.disconnect(this); if (cameras_.empty()) return; disconnect(); } /** * \brief Device disconnection handler * * This virtual function is called to notify the pipeline handler that the * device it handles has been disconnected. It notifies all cameras created by * the pipeline handler that they have been disconnected, and unregisters them * from the camera manager. * * The function can be overloaded by pipeline handlers to perform custom * operations at disconnection time. Any overloaded version shall call the * PipelineHandler::disconnect() base function for proper hot-unplug operation. */ void PipelineHandler::disconnect() { /* * Each camera holds a reference to its associated pipeline handler * instance. Hence, when the last camera is dropped, the pipeline * handler will get destroyed by the last manager_->removeCamera(camera) * call in the loop below. * * This is acceptable as long as we make sure that the code path does not * access any member of the (already destroyed) pipeline handler instance * afterwards. Therefore, we move the cameras_ vector to a local temporary * container to avoid accessing freed memory later i.e. to explicitly run * cameras_.clear(). */ std::vector> cameras{ std::move(cameras_) }; for (std::weak_ptr ptr : cameras) { std::shared_ptr camera = ptr.lock(); if (!camera) continue; camera->disconnect(); manager_->removeCamera(camera); } } /** * \brief Retrieve the pipeline-specific data associated with a Camera * \param[in] camera The camera whose data to retrieve * \return A pointer to the pipeline-specific data passed to registerCamera(). * The returned pointer is a borrowed reference and is guaranteed to remain * valid until the pipeline handler is destroyed. It shall not be deleted * manually by the caller. */ CameraData *PipelineHandler::cameraData(const Camera *camera) { ASSERT(cameraData_.count(camera)); return cameraData_[camera].get(); } /** * \brief Retrieve the pipeline-specific data associated with a Camera * \param[in] camera The camera whose data to retrieve * \sa cameraData() * \return A const pointer to the pipeline-specific data passed to * registerCamera(). */ const CameraData *PipelineHandler::cameraData(const Camera *camera) const { ASSERT(cameraData_.count(camera)); return cameraData_.at(camera).get(); } /** * \var PipelineHandler::manager_ * \brief The Camera manager associated with the pipeline handler * * The camera manager pointer is stored in the pipeline handler for the * convenience of pipeline handler implementations. It remains valid and * constant for the whole lifetime of the pipeline handler. */ /** * \fn PipelineHandler::name() * \brief Retrieve the pipeline handler name * \context This function shall be \threadsafe. * \return The pipeline handler name */ /** * \class PipelineHandlerFactory * \brief Registration of PipelineHandler classes and creation of instances * * To facilitate discovery and instantiation of PipelineHandler classes, the * PipelineHandlerFactory class maintains a registry of pipeline handler * classes. Each PipelineHandler subclass shall register itself using the * REGISTER_PIPELINE_HANDLER() macro, which will create a corresponding * instance of a PipelineHandlerFactory subclass and register it with the * static list of factories. */ /** * \brief Construct a pipeline handler factory * \param[in] name Name of the pipeline handler class * * Creating an instance of the factory registers is with the global list of * factories, accessible through the factories() function. * * The factory \a name is used for debug purpose and shall be unique. */ PipelineHandlerFactory::PipelineHandlerFactory(const char *name) : name_(name) { registerType(this); } /** * \brief Create an instance of the PipelineHandler corresponding to the factory * \param[in] manager The camera manager * * \return A shared pointer to a new instance of the PipelineHandler subclass * corresponding to the factory */ std::shared_ptr PipelineHandlerFactory::create(CameraManager *manager) { PipelineHandler *handler = createInstance(manager); handler->name_ = name_.c_str(); return std::shared_ptr(handler); } /** * \fn PipelineHandlerFactory::name() * \brief Retrieve the factory name * \return The factory name */ /** * \brief Add a pipeline handler class to the registry * \param[in] factory Factory to use to construct the pipeline handler * * The caller is responsible to guarantee the uniqueness of the pipeline handler * name. */ void PipelineHandlerFactory::registerType(PipelineHandlerFactory *factory) { std::vector &factories = PipelineHandlerFactory::factories(); factories.push_back(factory); } /** * \brief Retrieve the list of all pipeline handler factories * \return the list of pipeline handler factories */ std::vector &PipelineHandlerFactory::factories() { /* * The static factories map is defined inside the function to ensure * it gets initialized on first use, without any dependency on * link order. */ static std::vector factories; return factories; } /** * \fn PipelineHandlerFactory::createInstance() * \brief Create an instance of the PipelineHandler corresponding to the factory * \param[in] manager The camera manager * * This virtual function is implemented by the REGISTER_PIPELINE_HANDLER() * macro. It creates a pipeline handler instance associated with the camera * \a manager. * * \return a pointer to a newly constructed instance of the PipelineHandler * subclass corresponding to the factory */ /** * \def REGISTER_PIPELINE_HANDLER * \brief Register a pipeline handler with the pipeline handler factory * \param[in] handler Class name of PipelineHandler derived class to register * * Register a PipelineHandler subclass with the factory and make it available to * try and match devices. */ } /* namespace libcamera */