1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * v4l2-event.c 4 * 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 21 static 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 27 static 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 59 int 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 } 85 EXPORT_SYMBOL_GPL(v4l2_event_dequeue); 86 87 /* Caller must hold fh->vdev->fh_lock! */ 88 static 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 } 101 102 static 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 } 152 153 void 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 } 171 EXPORT_SYMBOL_GPL(v4l2_event_queue); 172 173 void 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 } 182 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh); 183 184 int v4l2_event_pending(struct v4l2_fh *fh) 185 { 186 return fh->navailable; 187 } 188 EXPORT_SYMBOL_GPL(v4l2_event_pending); 189 190 void 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 } 205 EXPORT_SYMBOL_GPL(v4l2_event_wake_all); 206 207 static 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 } 222 223 int 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 for (i = 0; i < elems; i++) 242 sev->events[i].sev = sev; 243 sev->type = sub->type; 244 sev->id = sub->id; 245 sev->flags = sub->flags; 246 sev->fh = fh; 247 sev->ops = ops; 248 sev->elems = elems; 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 } 275 EXPORT_SYMBOL_GPL(v4l2_event_subscribe); 276 277 void 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 } 298 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all); 299 300 int 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 } 330 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe); 331 332 int 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 } 337 EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe); 338 339 static 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 } 347 348 static 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 } 353 354 static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = { 355 .replace = v4l2_event_src_replace, 356 .merge = v4l2_event_src_merge, 357 }; 358 359 int 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 } 366 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe); 367 368 int 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 } 373 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe); 374