diff options
| -rw-r--r-- | src/libcamera/include/media_device.h | 56 | ||||
| -rw-r--r-- | src/libcamera/media_device.cpp | 375 | ||||
| -rw-r--r-- | src/libcamera/meson.build | 2 |
3 files changed, 433 insertions, 0 deletions
diff --git a/src/libcamera/include/media_device.h b/src/libcamera/include/media_device.h new file mode 100644 index 00000000..bca7c9a1 --- /dev/null +++ b/src/libcamera/include/media_device.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2018, Google Inc. + * + * media_device.h - Media device handler + */ +#ifndef __LIBCAMERA_MEDIA_DEVICE_H__ +#define __LIBCAMERA_MEDIA_DEVICE_H__ + +#include <map> +#include <sstream> +#include <string> +#include <vector> + +#include <linux/media.h> + +#include "media_object.h" + +namespace libcamera { + +class MediaDevice +{ +public: + MediaDevice(const std::string &devnode); + ~MediaDevice(); + + int open(); + void close(); + + int populate(); + + const std::string driver() const { return driver_; } + const std::string devnode() const { return devnode_; } + const std::vector<MediaEntity *> &entities() const { return entities_; } + +private: + std::string driver_; + std::string devnode_; + int fd_; + + std::map<unsigned int, MediaObject *> objects_; + MediaObject *object(unsigned int id); + int addObject(MediaObject *obj); + void clear(); + + std::vector<MediaEntity *> entities_; + MediaEntity *getEntityByName(const std::string &name); + + void populateEntities(const struct media_v2_topology &topology); + int populatePads(const struct media_v2_topology &topology); + int populateLinks(const struct media_v2_topology &topology); +}; + +} /* namespace libcamera */ + +#endif /* __LIBCAMERA_MEDIA_DEVICE_H__ */ diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp new file mode 100644 index 00000000..d9a5196a --- /dev/null +++ b/src/libcamera/media_device.cpp @@ -0,0 +1,375 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2018, Google Inc. + * + * media_device.cpp - Media device handler + */ + +#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" +#include "media_device.h" + +/** + * \file media_device.h + * \brief Provide a representation of a Linux kernel Media Controller device + * that exposes the full graph topology. + */ + +namespace libcamera { + +/** + * \class MediaDevice + * \brief The MediaDevice represents a Media Controller device with its full + * graph of connected objects. + * + * Media devices are created with an empty graph, which must be populated from + * + * + * The caller is responsible for opening the MediaDevice explicitly before + * operating on it, and shall close it when not needed anymore, as access + * to the MediaDevice is exclusive. + * + * A MediaDevice is created empty and gets populated by inspecting the media + * graph topology using the MEDIA_IOC_G_TOPOLOGY ioctls. Representation + * of each entity, pad and link described are created using MediaObject + * derived classes. + * + * All MediaObject are stored in a global pool, where they could be retrieved + * from by their globally unique id. + * + * References to MediaEntity registered in the graph are stored in a vector + * to allow easier by-name lookup, and the list of MediaEntities is accessible. + */ + +/** + * \brief Construct a MediaDevice + * \param devnode The media device node path + */ +MediaDevice::MediaDevice(const std::string &devnode) + : devnode_(devnode), fd_(-1) +{ +} + +/** + * \brief Close the media device file descriptor and delete all object + */ +MediaDevice::~MediaDevice() +{ + if (fd_ != -1) + ::close(fd_); + clear(); +} + +/** + * \fn MediaDevice::driver() + * \brief Retrieve the media device driver name + * \return The name of the kernel driver that handles the MediaDevice + */ + +/** + * \fn MediaDevice::devnode() + * \brief Retrieve the media device device node path + * \return The MediaDevice devnode path + */ + +/** + * \brief Delete all media objects in the MediaDevice. + * + * Delete all MediaEntities; entities will then delete their pads, + * and each source pad will delete links. + * + * After this function has been called, the media graph will be unpopulated + * and its media objects deleted. The media device has to be populated + * before it could be used again. + */ +void MediaDevice::clear() +{ + for (auto const &o : objects_) + delete o.second; + + objects_.clear(); + entities_.clear(); +} + +/** + * \brief Open a media device and retrieve informations from it + * + * The function fails if the media device is already open or if either + * open or the media device information retrieval operations fail. + * \return 0 for success or a negative error number otherwise + */ +int MediaDevice::open() +{ + if (fd_ != -1) { + LOG(Error) << "MediaDevice already open"; + return -EBUSY; + } + + int ret = ::open(devnode_.c_str(), O_RDWR); + if (ret < 0) { + ret = -errno; + LOG(Error) << "Failed to open media device at " << devnode_ + << ": " << strerror(-ret); + return ret; + } + fd_ = ret; + + struct media_device_info info = { }; + ret = ioctl(fd_, MEDIA_IOC_DEVICE_INFO, &info); + if (ret) { + ret = -errno; + LOG(Error) << "Failed to get media device info " + << ": " << strerror(-ret); + return ret; + } + + driver_ = info.driver; + + return 0; +} + +/** + * \brief Close the file descriptor associated with the media device. + * + * After this function has been called, for the MediaDevice to be operated on, + * the caller shall open it again. + */ +void MediaDevice::close() +{ + if (fd_ == -1) + return; + + ::close(fd_); + fd_ = -1; +} + +/** + * \fn MediaDevice::entities() + * \brief Retrieve the list of entities in the media graph + * \return The list of MediaEntities registered in the MediaDevice + */ + +/* + * Add a new object to the global objects pool and fail if the object + * has already been registered. + */ +int MediaDevice::addObject(MediaObject *obj) +{ + + if (objects_.find(obj->id()) != objects_.end()) { + LOG(Error) << "Element with id " << obj->id() + << " already enumerated."; + return -EEXIST; + } + + objects_[obj->id()] = obj; + + return 0; +} + +/* + * MediaObject pool lookup by id. + */ +MediaObject *MediaDevice::object(unsigned int id) +{ + auto it = objects_.find(id); + return (it == objects_.end()) ? nullptr : it->second; +} + +/** + * \brief Return the MediaEntity with name \a name + * \param name The entity name + * \return The entity with \a name + * \return nullptr if no entity with \a name is found + */ +MediaEntity *MediaDevice::getEntityByName(const std::string &name) +{ + for (MediaEntity *e : entities_) + if (e->name() == name) + return e; + + return nullptr; +} + +int MediaDevice::populateLinks(const struct media_v2_topology &topology) +{ + media_v2_link *mediaLinks = reinterpret_cast<media_v2_link *> + (topology.ptr_links); + + for (unsigned int i = 0; i < topology.num_links; ++i) { + /* + * Skip links between entities and interfaces: we only care + * about pad-2-pad links here. + */ + if ((mediaLinks[i].flags & MEDIA_LNK_FL_LINK_TYPE) == + MEDIA_LNK_FL_INTERFACE_LINK) + continue; + + /* Store references to source and sink pads in the link. */ + unsigned int source_id = mediaLinks[i].source_id; + MediaPad *source = dynamic_cast<MediaPad *> + (object(source_id)); + if (!source) { + LOG(Error) << "Failed to find pad with id: " + << source_id; + return -ENODEV; + } + + unsigned int sink_id = mediaLinks[i].sink_id; + MediaPad *sink = dynamic_cast<MediaPad *> + (object(sink_id)); + if (!sink) { + LOG(Error) << "Failed to find pad with id: " + << sink_id; + return -ENODEV; + } + + MediaLink *link = new MediaLink(&mediaLinks[i], source, sink); + source->addLink(link); + sink->addLink(link); + + addObject(link); + } + + return 0; +} + +int MediaDevice::populatePads(const struct media_v2_topology &topology) +{ + media_v2_pad *mediaPads = reinterpret_cast<media_v2_pad *> + (topology.ptr_pads); + + for (unsigned int i = 0; i < topology.num_pads; ++i) { + unsigned int entity_id = mediaPads[i].entity_id; + + /* Store a reference to this MediaPad in entity. */ + MediaEntity *mediaEntity = dynamic_cast<MediaEntity *> + (object(entity_id)); + if (!mediaEntity) { + LOG(Error) << "Failed to find entity with id: " + << entity_id; + return -ENODEV; + } + + MediaPad *pad = new MediaPad(&mediaPads[i], mediaEntity); + mediaEntity->addPad(pad); + + addObject(pad); + } + + return 0; +} + +/* + * For each entity in the media graph create a MediaEntity and store a + * reference in the MediaObject global pool and in the global vector of + * entities. + */ +void MediaDevice::populateEntities(const struct media_v2_topology &topology) +{ + media_v2_entity *mediaEntities = reinterpret_cast<media_v2_entity *> + (topology.ptr_entities); + + for (unsigned int i = 0; i < topology.num_entities; ++i) { + MediaEntity *entity = new MediaEntity(&mediaEntities[i]); + + addObject(entity); + entities_.push_back(entity); + } +} + +/** + * \brief Populate the media graph with media objects + * + * This function enumerates all media objects in the media device graph and + * creates their MediaObject representations. All entities, pads and links are + * stored as MediaEntity, MediaPad and MediaLink respectively, with cross- + * references between objects. Interfaces are not processed. + * + * MediaEntities are stored in a global list in the MediaDevice itself to ease + * lookup, while MediaPads are accessible from the MediaEntity they belong + * to only and MediaLinks from the MediaPad they connect. + * + * \return 0 on success, a negative error code otherwise + */ +int MediaDevice::populate() +{ + struct media_v2_topology topology = { }; + struct media_v2_entity *ents = nullptr; + struct media_v2_link *links = nullptr; + struct media_v2_pad *pads = nullptr; + __u64 version = -1; + int ret; + + /* + * Keep calling G_TOPOLOGY until the version number stays stable. + */ + while (true) { + topology.topology_version = 0; + topology.ptr_entities = reinterpret_cast<__u64>(ents); + topology.ptr_links = reinterpret_cast<__u64>(links); + topology.ptr_pads = reinterpret_cast<__u64>(pads); + + ret = ioctl(fd_, MEDIA_IOC_G_TOPOLOGY, &topology); + if (ret < 0) { + ret = -errno; + LOG(Error) << "Failed to enumerate topology: " + << strerror(-ret); + return ret; + } + + if (version == topology.topology_version) + break; + + delete[] links; + delete[] ents; + delete[] pads; + + ents = new media_v2_entity[topology.num_entities]; + links = new media_v2_link[topology.num_links]; + pads = new media_v2_pad[topology.num_pads]; + + version = topology.topology_version; + } + + /* Populate entities, pads and links. */ + populateEntities(topology); + + ret = populatePads(topology); + if (ret) + goto error_free_objs; + + ret = populateLinks(topology); +error_free_objs: + if (ret) + clear(); + + delete[] links; + delete[] ents; + delete[] pads; + + return ret; +} + +/** + * \var MediaDevice::objects_ + * \brief Global map of media objects (entities, pads, links) keyed by their + * object id. + */ + +/** + * \var MediaDevice::entities_ + * \brief Global list of media entities in the media graph + */ + +} /* namespace libcamera */ diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build index 2985d40c..2ff5bb5e 100644 --- a/src/libcamera/meson.build +++ b/src/libcamera/meson.build @@ -4,6 +4,7 @@ libcamera_sources = files([ 'device_enumerator.cpp', 'log.cpp', 'main.cpp', + 'media_device.cpp', 'media_object.cpp', 'pipeline_handler.cpp', ]) @@ -11,6 +12,7 @@ libcamera_sources = files([ libcamera_headers = files([ 'include/device_enumerator.h', 'include/log.h', + 'include/media_device.h', 'include/media_object.h', 'include/pipeline_handler.h', 'include/utils.h', |