/* * v4l2-event.c * * V4L2 events. * * Copyright (C) 2009--2010 Nokia Corporation. * * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA */ #include <media/v4l2-dev.h> #include <media/v4l2-fh.h> #include <media/v4l2-event.h> #include <linux/sched.h> #include <linux/slab.h> int v4l2_event_init(struct v4l2_fh *fh) { fh->events = kzalloc(sizeof(*fh->events), GFP_KERNEL); if (fh->events == NULL) return -ENOMEM; init_waitqueue_head(&fh->events->wait); INIT_LIST_HEAD(&fh->events->free); INIT_LIST_HEAD(&fh->events->available); INIT_LIST_HEAD(&fh->events->subscribed); fh->events->sequence = -1; return 0; } EXPORT_SYMBOL_GPL(v4l2_event_init); int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n) { struct v4l2_events *events = fh->events; unsigned long flags; if (!events) { WARN_ON(1); return -ENOMEM; } while (events->nallocated < n) { struct v4l2_kevent *kev; kev = kzalloc(sizeof(*kev), GFP_KERNEL); if (kev == NULL) return -ENOMEM; spin_lock_irqsave(&fh->vdev->fh_lock, flags); list_add_tail(&kev->list, &events->free); events->nallocated++; spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); } return 0; } EXPORT_SYMBOL_GPL(v4l2_event_alloc); #define list_kfree(list, type, member) \ while (!list_empty(list)) { \ type *hi; \ hi = list_first_entry(list, type, member); \ list_del(&hi->member); \ kfree(hi); \ } void v4l2_event_free(struct v4l2_fh *fh) { struct v4l2_events *events = fh->events; if (!events) return; list_kfree(&events->free, struct v4l2_kevent, list); list_kfree(&events->available, struct v4l2_kevent, list); list_kfree(&events->subscribed, struct v4l2_subscribed_event, list); kfree(events); fh->events = NULL; } EXPORT_SYMBOL_GPL(v4l2_event_free); static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event) { struct v4l2_events *events = fh->events; struct v4l2_kevent *kev; unsigned long flags; spin_lock_irqsave(&fh->vdev->fh_lock, flags); if (list_empty(&events->available)) { spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); return -ENOENT; } WARN_ON(events->navailable == 0); kev = list_first_entry(&events->available, struct v4l2_kevent, list); list_move(&kev->list, &events->free); events->navailable--; kev->event.pending = events->navailable; *event = kev->event; spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); return 0; } int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, int nonblocking) { struct v4l2_events *events = fh->events; int ret; if (nonblocking) return __v4l2_event_dequeue(fh, event); /* Release the vdev lock while waiting */ if (fh->vdev->lock) mutex_unlock(fh->vdev->lock); do { ret = wait_event_interruptible(events->wait, events->navailable != 0); if (ret < 0) break; ret = __v4l2_event_dequeue(fh, event); } while (ret == -ENOENT); if (fh->vdev->lock) mutex_lock(fh->vdev->lock); return ret; } EXPORT_SYMBOL_GPL(v4l2_event_dequeue); /* Caller must hold fh->event->lock! */ static struct v4l2_subscribed_event *v4l2_event_subscribed( struct v4l2_fh *fh, u32 type) { struct v4l2_events *events = fh->events; struct v4l2_subscribed_event *sev; assert_spin_locked(&fh->vdev->fh_lock); list_for_each_entry(sev, &events->subscribed, list) { if (sev->type == type) return sev; } return NULL; } void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev) { struct v4l2_fh *fh; unsigned long flags; struct timespec timestamp; ktime_get_ts(×tamp); spin_lock_irqsave(&vdev->fh_lock, flags); list_for_each_entry(fh, &vdev->fh_list, list) { struct v4l2_events *events = fh->events; struct v4l2_kevent *kev; /* Are we subscribed? */ if (!v4l2_event_subscribed(fh, ev->type)) continue; /* Increase event sequence number on fh. */ events->sequence++; /* Do we have any free events? */ if (list_empty(&events->free)) continue; /* Take one and fill it. */ kev = list_first_entry(&events->free, struct v4l2_kevent, list); kev->event.type = ev->type; kev->event.u = ev->u; kev->event.timestamp = timestamp; kev->event.sequence = events->sequence; list_move_tail(&kev->list, &events->available); events->navailable++; wake_up_all(&events->wait); } spin_unlock_irqrestore(&vdev->fh_lock, flags); } EXPORT_SYMBOL_GPL(v4l2_event_queue); int v4l2_event_pending(struct v4l2_fh *fh) { return fh->events->navailable; } EXPORT_SYMBOL_GPL(v4l2_event_pending); int v4l2_event_subscribe(struct v4l2_fh *fh, struct v4l2_event_subscription *sub) { struct v4l2_events *events = fh->events; struct v4l2_subscribed_event *sev; unsigned long flags; if (fh->events == NULL) { WARN_ON(1); return -ENOMEM; } sev = kmalloc(sizeof(*sev), GFP_KERNEL); if (!sev) return -ENOMEM; spin_lock_irqsave(&fh->vdev->fh_lock, flags); if (v4l2_event_subscribed(fh, sub->type) == NULL) { INIT_LIST_HEAD(&sev->list); sev->type = sub->type; list_add(&sev->list, &events->subscribed); sev = NULL; } spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); kfree(sev); return 0; } EXPORT_SYMBOL_GPL(v4l2_event_subscribe); static void v4l2_event_unsubscribe_all(struct v4l2_fh *fh) { struct v4l2_events *events = fh->events; struct v4l2_subscribed_event *sev; unsigned long flags; do { sev = NULL; spin_lock_irqsave(&fh->vdev->fh_lock, flags); if (!list_empty(&events->subscribed)) { sev = list_first_entry(&events->subscribed, struct v4l2_subscribed_event, list); list_del(&sev->list); } spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); kfree(sev); } while (sev); } int v4l2_event_unsubscribe(struct v4l2_fh *fh, struct v4l2_event_subscription *sub) { struct v4l2_subscribed_event *sev; unsigned long flags; if (sub->type == V4L2_EVENT_ALL) { v4l2_event_unsubscribe_all(fh); return 0; } spin_lock_irqsave(&fh->vdev->fh_lock, flags); sev = v4l2_event_subscribed(fh, sub->type); if (sev != NULL) list_del(&sev->list); spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); kfree(sev); return 0; } EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);