--- /dev/null
+/*
+ * 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;
+}
+
+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;
+}
+
+/* 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;
+
+ WARN_ON(!spin_is_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);
--- /dev/null
+/*
+ * v4l2-event.h
+ *
+ * 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
+ */
+
+#ifndef V4L2_EVENT_H
+#define V4L2_EVENT_H
+
+#include <linux/types.h>
+#include <linux/videodev2.h>
+#include <linux/wait.h>
+
+struct v4l2_fh;
+struct video_device;
+
+struct v4l2_kevent {
+ struct list_head list;
+ struct v4l2_event event;
+};
+
+struct v4l2_subscribed_event {
+ struct list_head list;
+ u32 type;
+};
+
+struct v4l2_events {
+ wait_queue_head_t wait;
+ struct list_head subscribed; /* Subscribed events */
+ struct list_head free; /* Events ready for use */
+ struct list_head available; /* Dequeueable event */
+ unsigned int navailable;
+ unsigned int nallocated; /* Number of allocated events */
+ u32 sequence;
+};
+
+int v4l2_event_init(struct v4l2_fh *fh);
+int v4l2_event_alloc(struct v4l2_fh *fh, unsigned int n);
+void v4l2_event_free(struct v4l2_fh *fh);
+int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
+ int nonblocking);
+void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev);
+int v4l2_event_pending(struct v4l2_fh *fh);
+int v4l2_event_subscribe(struct v4l2_fh *fh,
+ struct v4l2_event_subscription *sub);
+int v4l2_event_unsubscribe(struct v4l2_fh *fh,
+ struct v4l2_event_subscription *sub);
+
+#endif /* V4L2_EVENT_H */
projects / linux.git / commitdiff