diff options
Diffstat (limited to 'drivers/media/video/v4l2-event.c')
| -rw-r--r-- | drivers/media/video/v4l2-event.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/drivers/media/video/v4l2-event.c b/drivers/media/video/v4l2-event.c new file mode 100644 index 00000000000..de74ce07b5e --- /dev/null +++ b/drivers/media/video/v4l2-event.c @@ -0,0 +1,292 @@ +/* + * 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); + + do { + ret = wait_event_interruptible(events->wait, + events->navailable != 0); + if (ret < 0) + return ret; + + ret = __v4l2_event_dequeue(fh, event); + } while (ret == -ENOENT); + + 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); |