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// SPDX-License-Identifier: GPL-2.0-only
/*
* v4l2-event.c
*
* V4L2 events.
*
* Copyright (C) 2009--2010 Nokia Corporation.
*
* Contact: Sakari Ailus <sakari.ailus@iki.fi>
*/
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/export.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;
struct timespec64 ts;
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;
ts = ns_to_timespec64(kev->ts);
event->timestamp.tv_sec = ts.tv_sec;
event->timestamp.tv_nsec = ts.tv_nsec;
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, u64 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->ops && sev->ops->replace) {
sev->ops->replace(&kev->event, ev);
copy_payload = false;
}
} else if (sev->ops && sev->ops->merge) {
struct v4l2_kevent *second_oldest =
sev->events + sev_pos(sev, 0);
sev->ops->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->ts = 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;
u64 ts;
if (vdev == NULL)
return;
ts = ktime_get_ns();
spin_lock_irqsave(&vdev->fh_lock, flags);
list_for_each_entry(fh, &vdev->fh_list, list)
__v4l2_event_queue_fh(fh, ev, ts);
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;
u64 ts = ktime_get_ns();
spin_lock_irqsave(&fh->vdev->fh_lock, flags);
__v4l2_event_queue_fh(fh, ev, ts);
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 __v4l2_event_unsubscribe(struct v4l2_subscribed_event *sev)
{
struct v4l2_fh *fh = sev->fh;
unsigned int i;
lockdep_assert_held(&fh->subscribe_lock);
assert_spin_locked(&fh->vdev->fh_lock);
/* Remove any pending events for this subscription */
for (i = 0; i < sev->in_use; i++) {
list_del(&sev->events[sev_pos(sev, i)].list);
fh->navailable--;
}
list_del(&sev->list);
}
int v4l2_event_subscribe(struct v4l2_fh *fh,
const struct v4l2_event_subscription *sub, unsigned elems,
const struct v4l2_subscribed_event_ops *ops)
{
struct v4l2_subscribed_event *sev, *found_ev;
unsigned long flags;
unsigned i;
int ret = 0;
if (sub->type == V4L2_EVENT_ALL)
return -EINVAL;
if (elems < 1)
elems = 1;
sev = kvzalloc(struct_size(sev, events, 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->ops = ops;
sev->elems = elems;
mutex_lock(&fh->subscribe_lock);
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);
if (found_ev) {
/* Already listening */
kvfree(sev);
} else if (sev->ops && sev->ops->add) {
ret = sev->ops->add(sev, elems);
if (ret) {
spin_lock_irqsave(&fh->vdev->fh_lock, flags);
__v4l2_event_unsubscribe(sev);
spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
kvfree(sev);
}
}
mutex_unlock(&fh->subscribe_lock);
return ret;
}
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,
const 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;
}
mutex_lock(&fh->subscribe_lock);
spin_lock_irqsave(&fh->vdev->fh_lock, flags);
sev = v4l2_event_subscribed(fh, sub->type, sub->id);
if (sev != NULL)
__v4l2_event_unsubscribe(sev);
spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
if (sev && sev->ops && sev->ops->del)
sev->ops->del(sev);
mutex_unlock(&fh->subscribe_lock);
kvfree(sev);
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);
int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,
struct v4l2_event_subscription *sub)
{
return v4l2_event_unsubscribe(fh, sub);
}
EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);
static void v4l2_event_src_replace(struct v4l2_event *old,
const struct v4l2_event *new)
{
u32 old_changes = old->u.src_change.changes;
old->u.src_change = new->u.src_change;
old->u.src_change.changes |= old_changes;
}
static void v4l2_event_src_merge(const struct v4l2_event *old,
struct v4l2_event *new)
{
new->u.src_change.changes |= old->u.src_change.changes;
}
static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
.replace = v4l2_event_src_replace,
.merge = v4l2_event_src_merge,
};
int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
const struct v4l2_event_subscription *sub)
{
if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
return -EINVAL;
}
EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);
int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
{
return v4l2_src_change_event_subscribe(fh, sub);
}
EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);