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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * v4l2-event.c4 *5 * V4L2 events.6 *7 * Copyright (C) 2009--2010 Nokia Corporation.8 *9 * Contact: Sakari Ailus <sakari.ailus@iki.fi>10 */11 12#include <media/v4l2-dev.h>13#include <media/v4l2-fh.h>14#include <media/v4l2-event.h>15 16#include <linux/mm.h>17#include <linux/sched.h>18#include <linux/slab.h>19#include <linux/export.h>20 21static unsigned int sev_pos(const struct v4l2_subscribed_event *sev, unsigned int idx)22{23 idx += sev->first;24 return idx >= sev->elems ? idx - sev->elems : idx;25}26 27static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)28{29 struct v4l2_kevent *kev;30 struct timespec64 ts;31 unsigned long flags;32 33 spin_lock_irqsave(&fh->vdev->fh_lock, flags);34 35 if (list_empty(&fh->available)) {36 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);37 return -ENOENT;38 }39 40 WARN_ON(fh->navailable == 0);41 42 kev = list_first_entry(&fh->available, struct v4l2_kevent, list);43 list_del(&kev->list);44 fh->navailable--;45 46 kev->event.pending = fh->navailable;47 *event = kev->event;48 ts = ns_to_timespec64(kev->ts);49 event->timestamp.tv_sec = ts.tv_sec;50 event->timestamp.tv_nsec = ts.tv_nsec;51 kev->sev->first = sev_pos(kev->sev, 1);52 kev->sev->in_use--;53 54 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);55 56 return 0;57}58 59int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,60 int nonblocking)61{62 int ret;63 64 if (nonblocking)65 return __v4l2_event_dequeue(fh, event);66 67 /* Release the vdev lock while waiting */68 if (fh->vdev->lock)69 mutex_unlock(fh->vdev->lock);70 71 do {72 ret = wait_event_interruptible(fh->wait,73 fh->navailable != 0);74 if (ret < 0)75 break;76 77 ret = __v4l2_event_dequeue(fh, event);78 } while (ret == -ENOENT);79 80 if (fh->vdev->lock)81 mutex_lock(fh->vdev->lock);82 83 return ret;84}85EXPORT_SYMBOL_GPL(v4l2_event_dequeue);86 87/* Caller must hold fh->vdev->fh_lock! */88static struct v4l2_subscribed_event *v4l2_event_subscribed(89 struct v4l2_fh *fh, u32 type, u32 id)90{91 struct v4l2_subscribed_event *sev;92 93 assert_spin_locked(&fh->vdev->fh_lock);94 95 list_for_each_entry(sev, &fh->subscribed, list)96 if (sev->type == type && sev->id == id)97 return sev;98 99 return NULL;100}101 102static void __v4l2_event_queue_fh(struct v4l2_fh *fh,103 const struct v4l2_event *ev, u64 ts)104{105 struct v4l2_subscribed_event *sev;106 struct v4l2_kevent *kev;107 bool copy_payload = true;108 109 /* Are we subscribed? */110 sev = v4l2_event_subscribed(fh, ev->type, ev->id);111 if (sev == NULL)112 return;113 114 /* Increase event sequence number on fh. */115 fh->sequence++;116 117 /* Do we have any free events? */118 if (sev->in_use == sev->elems) {119 /* no, remove the oldest one */120 kev = sev->events + sev_pos(sev, 0);121 list_del(&kev->list);122 sev->in_use--;123 sev->first = sev_pos(sev, 1);124 fh->navailable--;125 if (sev->elems == 1) {126 if (sev->ops && sev->ops->replace) {127 sev->ops->replace(&kev->event, ev);128 copy_payload = false;129 }130 } else if (sev->ops && sev->ops->merge) {131 struct v4l2_kevent *second_oldest =132 sev->events + sev_pos(sev, 0);133 sev->ops->merge(&kev->event, &second_oldest->event);134 }135 }136 137 /* Take one and fill it. */138 kev = sev->events + sev_pos(sev, sev->in_use);139 kev->event.type = ev->type;140 if (copy_payload)141 kev->event.u = ev->u;142 kev->event.id = ev->id;143 kev->ts = ts;144 kev->event.sequence = fh->sequence;145 sev->in_use++;146 list_add_tail(&kev->list, &fh->available);147 148 fh->navailable++;149 150 wake_up_all(&fh->wait);151}152 153void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev)154{155 struct v4l2_fh *fh;156 unsigned long flags;157 u64 ts;158 159 if (vdev == NULL)160 return;161 162 ts = ktime_get_ns();163 164 spin_lock_irqsave(&vdev->fh_lock, flags);165 166 list_for_each_entry(fh, &vdev->fh_list, list)167 __v4l2_event_queue_fh(fh, ev, ts);168 169 spin_unlock_irqrestore(&vdev->fh_lock, flags);170}171EXPORT_SYMBOL_GPL(v4l2_event_queue);172 173void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev)174{175 unsigned long flags;176 u64 ts = ktime_get_ns();177 178 spin_lock_irqsave(&fh->vdev->fh_lock, flags);179 __v4l2_event_queue_fh(fh, ev, ts);180 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);181}182EXPORT_SYMBOL_GPL(v4l2_event_queue_fh);183 184int v4l2_event_pending(struct v4l2_fh *fh)185{186 return fh->navailable;187}188EXPORT_SYMBOL_GPL(v4l2_event_pending);189 190void v4l2_event_wake_all(struct video_device *vdev)191{192 struct v4l2_fh *fh;193 unsigned long flags;194 195 if (!vdev)196 return;197 198 spin_lock_irqsave(&vdev->fh_lock, flags);199 200 list_for_each_entry(fh, &vdev->fh_list, list)201 wake_up_all(&fh->wait);202 203 spin_unlock_irqrestore(&vdev->fh_lock, flags);204}205EXPORT_SYMBOL_GPL(v4l2_event_wake_all);206 207static void __v4l2_event_unsubscribe(struct v4l2_subscribed_event *sev)208{209 struct v4l2_fh *fh = sev->fh;210 unsigned int i;211 212 lockdep_assert_held(&fh->subscribe_lock);213 assert_spin_locked(&fh->vdev->fh_lock);214 215 /* Remove any pending events for this subscription */216 for (i = 0; i < sev->in_use; i++) {217 list_del(&sev->events[sev_pos(sev, i)].list);218 fh->navailable--;219 }220 list_del(&sev->list);221}222 223int v4l2_event_subscribe(struct v4l2_fh *fh,224 const struct v4l2_event_subscription *sub, unsigned int elems,225 const struct v4l2_subscribed_event_ops *ops)226{227 struct v4l2_subscribed_event *sev, *found_ev;228 unsigned long flags;229 unsigned int i;230 int ret = 0;231 232 if (sub->type == V4L2_EVENT_ALL)233 return -EINVAL;234 235 if (elems < 1)236 elems = 1;237 238 sev = kvzalloc(struct_size(sev, events, elems), GFP_KERNEL);239 if (!sev)240 return -ENOMEM;241 sev->elems = elems;242 for (i = 0; i < elems; i++)243 sev->events[i].sev = sev;244 sev->type = sub->type;245 sev->id = sub->id;246 sev->flags = sub->flags;247 sev->fh = fh;248 sev->ops = ops;249 250 mutex_lock(&fh->subscribe_lock);251 252 spin_lock_irqsave(&fh->vdev->fh_lock, flags);253 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);254 if (!found_ev)255 list_add(&sev->list, &fh->subscribed);256 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);257 258 if (found_ev) {259 /* Already listening */260 kvfree(sev);261 } else if (sev->ops && sev->ops->add) {262 ret = sev->ops->add(sev, elems);263 if (ret) {264 spin_lock_irqsave(&fh->vdev->fh_lock, flags);265 __v4l2_event_unsubscribe(sev);266 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);267 kvfree(sev);268 }269 }270 271 mutex_unlock(&fh->subscribe_lock);272 273 return ret;274}275EXPORT_SYMBOL_GPL(v4l2_event_subscribe);276 277void v4l2_event_unsubscribe_all(struct v4l2_fh *fh)278{279 struct v4l2_event_subscription sub;280 struct v4l2_subscribed_event *sev;281 unsigned long flags;282 283 do {284 sev = NULL;285 286 spin_lock_irqsave(&fh->vdev->fh_lock, flags);287 if (!list_empty(&fh->subscribed)) {288 sev = list_first_entry(&fh->subscribed,289 struct v4l2_subscribed_event, list);290 sub.type = sev->type;291 sub.id = sev->id;292 }293 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);294 if (sev)295 v4l2_event_unsubscribe(fh, &sub);296 } while (sev);297}298EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all);299 300int v4l2_event_unsubscribe(struct v4l2_fh *fh,301 const struct v4l2_event_subscription *sub)302{303 struct v4l2_subscribed_event *sev;304 unsigned long flags;305 306 if (sub->type == V4L2_EVENT_ALL) {307 v4l2_event_unsubscribe_all(fh);308 return 0;309 }310 311 mutex_lock(&fh->subscribe_lock);312 313 spin_lock_irqsave(&fh->vdev->fh_lock, flags);314 315 sev = v4l2_event_subscribed(fh, sub->type, sub->id);316 if (sev != NULL)317 __v4l2_event_unsubscribe(sev);318 319 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);320 321 if (sev && sev->ops && sev->ops->del)322 sev->ops->del(sev);323 324 mutex_unlock(&fh->subscribe_lock);325 326 kvfree(sev);327 328 return 0;329}330EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe);331 332int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh,333 struct v4l2_event_subscription *sub)334{335 return v4l2_event_unsubscribe(fh, sub);336}337EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);338 339static void v4l2_event_src_replace(struct v4l2_event *old,340 const struct v4l2_event *new)341{342 u32 old_changes = old->u.src_change.changes;343 344 old->u.src_change = new->u.src_change;345 old->u.src_change.changes |= old_changes;346}347 348static void v4l2_event_src_merge(const struct v4l2_event *old,349 struct v4l2_event *new)350{351 new->u.src_change.changes |= old->u.src_change.changes;352}353 354static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {355 .replace = v4l2_event_src_replace,356 .merge = v4l2_event_src_merge,357};358 359int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,360 const struct v4l2_event_subscription *sub)361{362 if (sub->type == V4L2_EVENT_SOURCE_CHANGE)363 return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);364 return -EINVAL;365}366EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);367 368int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,369 struct v4l2_fh *fh, struct v4l2_event_subscription *sub)370{371 return v4l2_src_change_event_subscribe(fh, sub);372}373EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);374