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 000000000000..de74ce07b5e2
--- /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(&timestamp);
+
+        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);