1 files changed, 311 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..53b190cf225
--- /dev/null
+++ b/drivers/media/video/v4l2-event.c
@@ -0,0 +1,311 @@
+/*
+ * 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 <media/v4l2-ctrls.h>
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
+{
+        idx += sev->first;
+        return idx >= sev->elems ? idx - sev->elems : idx;
+}
+
+static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
+{
+        struct v4l2_kevent *kev;
+        unsigned long flags;
+
+        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
+
+        if (list_empty(&fh->available)) {
+                spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+                return -ENOENT;
+        }
+
+        WARN_ON(fh->navailable == 0);
+
+        kev = list_first_entry(&fh->available, struct v4l2_kevent, list);
+        list_del(&kev->list);
+        fh->navailable--;
+
+        kev->event.pending = fh->navailable;
+        *event = kev->event;
+        kev->sev->first = sev_pos(kev->sev, 1);
+        kev->sev->in_use--;
+
+        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+
+        return 0;
+}
+
+int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
+                       int nonblocking)
+{
+        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(fh->wait,
+                                               fh->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->vdev->fh_lock! */
+static struct v4l2_subscribed_event *v4l2_event_subscribed(
+                struct v4l2_fh *fh, u32 type, u32 id)
+{
+        struct v4l2_subscribed_event *sev;
+
+        assert_spin_locked(&fh->vdev->fh_lock);
+
+        list_for_each_entry(sev, &fh->subscribed, list)
+                if (sev->type == type && sev->id == id)
+                        return sev;
+
+        return NULL;
+}
+
+static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev,
+                const struct timespec *ts)
+{
+        struct v4l2_subscribed_event *sev;
+        struct v4l2_kevent *kev;
+        bool copy_payload = true;
+
+        /* Are we subscribed? */
+        sev = v4l2_event_subscribed(fh, ev->type, ev->id);
+        if (sev == NULL)
+                return;
+
+        /* Increase event sequence number on fh. */
+        fh->sequence++;
+
+        /* Do we have any free events? */
+        if (sev->in_use == sev->elems) {
+                /* no, remove the oldest one */
+                kev = sev->events + sev_pos(sev, 0);
+                list_del(&kev->list);
+                sev->in_use--;
+                sev->first = sev_pos(sev, 1);
+                fh->navailable--;
+                if (sev->elems == 1) {
+                        if (sev->replace) {
+                                sev->replace(&kev->event, ev);
+                                copy_payload = false;
+                        }
+                } else if (sev->merge) {
+                        struct v4l2_kevent *second_oldest =
+                                sev->events + sev_pos(sev, 0);
+                        sev->merge(&kev->event, &second_oldest->event);
+                }
+        }
+
+        /* Take one and fill it. */
+        kev = sev->events + sev_pos(sev, sev->in_use);
+        kev->event.type = ev->type;
+        if (copy_payload)
+                kev->event.u = ev->u;
+        kev->event.id = ev->id;
+        kev->event.timestamp = *ts;
+        kev->event.sequence = fh->sequence;
+        sev->in_use++;
+        list_add_tail(&kev->list, &fh->available);
+
+        fh->navailable++;
+
+        wake_up_all(&fh->wait);
+}
+
+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)
+                __v4l2_event_queue_fh(fh, ev, &timestamp);
+
+        spin_unlock_irqrestore(&vdev->fh_lock, flags);
+}
+EXPORT_SYMBOL_GPL(v4l2_event_queue);
+
+void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)
+{
+        unsigned long flags;
+        struct timespec timestamp;
+
+        ktime_get_ts(&timestamp);
+
+        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
+        __v4l2_event_queue_fh(fh, ev, &timestamp);
+        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+}
+EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);
+
+int v4l2_event_pending(struct v4l2_fh *fh)
+{
+        return fh->navailable;
+}
+EXPORT_SYMBOL_GPL(v4l2_event_pending);
+
+static void ctrls_replace(struct v4l2_event *old, const struct v4l2_event *new)
+{
+        u32 old_changes = old->u.ctrl.changes;
+
+        old->u.ctrl = new->u.ctrl;
+        old->u.ctrl.changes |= old_changes;
+}
+
+static void ctrls_merge(const struct v4l2_event *old, struct v4l2_event *new)
+{
+        new->u.ctrl.changes |= old->u.ctrl.changes;
+}
+
+int v4l2_event_subscribe(struct v4l2_fh *fh,
+                         struct v4l2_event_subscription *sub, unsigned elems)
+{
+        struct v4l2_subscribed_event *sev, *found_ev;
+        struct v4l2_ctrl *ctrl = NULL;
+        unsigned long flags;
+        unsigned i;
+
+        if (elems < 1)
+                elems = 1;
+        if (sub->type == V4L2_EVENT_CTRL) {
+                ctrl = v4l2_ctrl_find(fh->ctrl_handler, sub->id);
+                if (ctrl == NULL)
+                        return -EINVAL;
+        }
+
+        sev = kzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems, GFP_KERNEL);
+        if (!sev)
+                return -ENOMEM;
+        for (i = 0; i < elems; i++)
+                sev->events[i].sev = sev;
+        sev->type = sub->type;
+        sev->id = sub->id;
+        sev->flags = sub->flags;
+        sev->fh = fh;
+        sev->elems = elems;
+        if (ctrl) {
+                sev->replace = ctrls_replace;
+                sev->merge = ctrls_merge;
+        }
+
+        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
+        found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
+        if (!found_ev)
+                list_add(&sev->list, &fh->subscribed);
+        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+
+        /* v4l2_ctrl_add_event uses a mutex, so do this outside the spin lock */
+        if (found_ev)
+                kfree(sev);
+        else if (ctrl)
+                v4l2_ctrl_add_event(ctrl, sev);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_event_subscribe);
+
+void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)
+{
+        struct v4l2_event_subscription sub;
+        struct v4l2_subscribed_event *sev;
+        unsigned long flags;
+
+        do {
+                sev = NULL;
+
+                spin_lock_irqsave(&fh->vdev->fh_lock, flags);
+                if (!list_empty(&fh->subscribed)) {
+                        sev = list_first_entry(&fh->subscribed,
+                                        struct v4l2_subscribed_event, list);
+                        sub.type = sev->type;
+                        sub.id = sev->id;
+                }
+                spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+                if (sev)
+                        v4l2_event_unsubscribe(fh, &sub);
+        } while (sev);
+}
+EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);
+
+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, sub->id);
+        if (sev != NULL) {
+                list_del(&sev->list);
+                sev->fh = NULL;
+        }
+
+        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
+        if (sev && sev->type == V4L2_EVENT_CTRL) {
+                struct v4l2_ctrl *ctrl = v4l2_ctrl_find(fh->ctrl_handler, sev->id);
+
+                if (ctrl)
+                        v4l2_ctrl_del_event(ctrl, sev);
+        }
+
+        kfree(sev);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);