1 /* 2 * v4l2-event.c 3 * 4 * V4L2 events. 5 * 6 * Copyright (C) 2009--2010 Nokia Corporation. 7 * 8 * Contact: Sakari Ailus <sakari.ailus@iki.fi> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * version 2 as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 22 * 02110-1301 USA 23 */ 24 25 #include <media/v4l2-dev.h> 26 #include <media/v4l2-fh.h> 27 #include <media/v4l2-event.h> 28 29 #include <linux/sched.h> 30 #include <linux/slab.h> 31 #include <linux/export.h> 32 33 static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx) 34 { 35 idx += sev->first; 36 return idx >= sev->elems ? idx - sev->elems : idx; 37 } 38 39 static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event) 40 { 41 struct v4l2_kevent *kev; 42 unsigned long flags; 43 44 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 45 46 if (list_empty(&fh->available)) { 47 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 48 return -ENOENT; 49 } 50 51 WARN_ON(fh->navailable == 0); 52 53 kev = list_first_entry(&fh->available, struct v4l2_kevent, list); 54 list_del(&kev->list); 55 fh->navailable--; 56 57 kev->event.pending = fh->navailable; 58 *event = kev->event; 59 kev->sev->first = sev_pos(kev->sev, 1); 60 kev->sev->in_use--; 61 62 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 63 64 return 0; 65 } 66 67 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, 68 int nonblocking) 69 { 70 int ret; 71 72 if (nonblocking) 73 return __v4l2_event_dequeue(fh, event); 74 75 /* Release the vdev lock while waiting */ 76 if (fh->vdev->lock) 77 mutex_unlock(fh->vdev->lock); 78 79 do { 80 ret = wait_event_interruptible(fh->wait, 81 fh->navailable != 0); 82 if (ret < 0) 83 break; 84 85 ret = __v4l2_event_dequeue(fh, event); 86 } while (ret == -ENOENT); 87 88 if (fh->vdev->lock) 89 mutex_lock(fh->vdev->lock); 90 91 return ret; 92 } 93 EXPORT_SYMBOL_GPL(v4l2_event_dequeue); 94 95 /* Caller must hold fh->vdev->fh_lock! */ 96 static struct v4l2_subscribed_event *v4l2_event_subscribed( 97 struct v4l2_fh *fh, u32 type, u32 id) 98 { 99 struct v4l2_subscribed_event *sev; 100 101 assert_spin_locked(&fh->vdev->fh_lock); 102 103 list_for_each_entry(sev, &fh->subscribed, list) 104 if (sev->type == type && sev->id == id) 105 return sev; 106 107 return NULL; 108 } 109 110 static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev, 111 const struct timespec *ts) 112 { 113 struct v4l2_subscribed_event *sev; 114 struct v4l2_kevent *kev; 115 bool copy_payload = true; 116 117 /* Are we subscribed? */ 118 sev = v4l2_event_subscribed(fh, ev->type, ev->id); 119 if (sev == NULL) 120 return; 121 122 /* 123 * If the event has been added to the fh->subscribed list, but its 124 * add op has not completed yet elems will be 0, treat this as 125 * not being subscribed. 126 */ 127 if (!sev->elems) 128 return; 129 130 /* Increase event sequence number on fh. */ 131 fh->sequence++; 132 133 /* Do we have any free events? */ 134 if (sev->in_use == sev->elems) { 135 /* no, remove the oldest one */ 136 kev = sev->events + sev_pos(sev, 0); 137 list_del(&kev->list); 138 sev->in_use--; 139 sev->first = sev_pos(sev, 1); 140 fh->navailable--; 141 if (sev->elems == 1) { 142 if (sev->ops && sev->ops->replace) { 143 sev->ops->replace(&kev->event, ev); 144 copy_payload = false; 145 } 146 } else if (sev->ops && sev->ops->merge) { 147 struct v4l2_kevent *second_oldest = 148 sev->events + sev_pos(sev, 0); 149 sev->ops->merge(&kev->event, &second_oldest->event); 150 } 151 } 152 153 /* Take one and fill it. */ 154 kev = sev->events + sev_pos(sev, sev->in_use); 155 kev->event.type = ev->type; 156 if (copy_payload) 157 kev->event.u = ev->u; 158 kev->event.id = ev->id; 159 kev->event.timestamp = *ts; 160 kev->event.sequence = fh->sequence; 161 sev->in_use++; 162 list_add_tail(&kev->list, &fh->available); 163 164 fh->navailable++; 165 166 wake_up_all(&fh->wait); 167 } 168 169 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev) 170 { 171 struct v4l2_fh *fh; 172 unsigned long flags; 173 struct timespec timestamp; 174 175 if (vdev == NULL) 176 return; 177 178 ktime_get_ts(×tamp); 179 180 spin_lock_irqsave(&vdev->fh_lock, flags); 181 182 list_for_each_entry(fh, &vdev->fh_list, list) 183 __v4l2_event_queue_fh(fh, ev, ×tamp); 184 185 spin_unlock_irqrestore(&vdev->fh_lock, flags); 186 } 187 EXPORT_SYMBOL_GPL(v4l2_event_queue); 188 189 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev) 190 { 191 unsigned long flags; 192 struct timespec timestamp; 193 194 ktime_get_ts(×tamp); 195 196 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 197 __v4l2_event_queue_fh(fh, ev, ×tamp); 198 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 199 } 200 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh); 201 202 int v4l2_event_pending(struct v4l2_fh *fh) 203 { 204 return fh->navailable; 205 } 206 EXPORT_SYMBOL_GPL(v4l2_event_pending); 207 208 int v4l2_event_subscribe(struct v4l2_fh *fh, 209 const struct v4l2_event_subscription *sub, unsigned elems, 210 const struct v4l2_subscribed_event_ops *ops) 211 { 212 struct v4l2_subscribed_event *sev, *found_ev; 213 unsigned long flags; 214 unsigned i; 215 216 if (sub->type == V4L2_EVENT_ALL) 217 return -EINVAL; 218 219 if (elems < 1) 220 elems = 1; 221 222 sev = kzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems, GFP_KERNEL); 223 if (!sev) 224 return -ENOMEM; 225 for (i = 0; i < elems; i++) 226 sev->events[i].sev = sev; 227 sev->type = sub->type; 228 sev->id = sub->id; 229 sev->flags = sub->flags; 230 sev->fh = fh; 231 sev->ops = ops; 232 233 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 234 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id); 235 if (!found_ev) 236 list_add(&sev->list, &fh->subscribed); 237 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 238 239 if (found_ev) { 240 kfree(sev); 241 return 0; /* Already listening */ 242 } 243 244 if (sev->ops && sev->ops->add) { 245 int ret = sev->ops->add(sev, elems); 246 if (ret) { 247 sev->ops = NULL; 248 v4l2_event_unsubscribe(fh, sub); 249 return ret; 250 } 251 } 252 253 /* Mark as ready for use */ 254 sev->elems = elems; 255 256 return 0; 257 } 258 EXPORT_SYMBOL_GPL(v4l2_event_subscribe); 259 260 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh) 261 { 262 struct v4l2_event_subscription sub; 263 struct v4l2_subscribed_event *sev; 264 unsigned long flags; 265 266 do { 267 sev = NULL; 268 269 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 270 if (!list_empty(&fh->subscribed)) { 271 sev = list_first_entry(&fh->subscribed, 272 struct v4l2_subscribed_event, list); 273 sub.type = sev->type; 274 sub.id = sev->id; 275 } 276 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 277 if (sev) 278 v4l2_event_unsubscribe(fh, &sub); 279 } while (sev); 280 } 281 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all); 282 283 int v4l2_event_unsubscribe(struct v4l2_fh *fh, 284 const struct v4l2_event_subscription *sub) 285 { 286 struct v4l2_subscribed_event *sev; 287 unsigned long flags; 288 int i; 289 290 if (sub->type == V4L2_EVENT_ALL) { 291 v4l2_event_unsubscribe_all(fh); 292 return 0; 293 } 294 295 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 296 297 sev = v4l2_event_subscribed(fh, sub->type, sub->id); 298 if (sev != NULL) { 299 /* Remove any pending events for this subscription */ 300 for (i = 0; i < sev->in_use; i++) { 301 list_del(&sev->events[sev_pos(sev, i)].list); 302 fh->navailable--; 303 } 304 list_del(&sev->list); 305 } 306 307 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 308 309 if (sev && sev->ops && sev->ops->del) 310 sev->ops->del(sev); 311 312 kfree(sev); 313 314 return 0; 315 } 316 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe); 317 318 int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh, 319 struct v4l2_event_subscription *sub) 320 { 321 return v4l2_event_unsubscribe(fh, sub); 322 } 323 EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe); 324 325 static void v4l2_event_src_replace(struct v4l2_event *old, 326 const struct v4l2_event *new) 327 { 328 u32 old_changes = old->u.src_change.changes; 329 330 old->u.src_change = new->u.src_change; 331 old->u.src_change.changes |= old_changes; 332 } 333 334 static void v4l2_event_src_merge(const struct v4l2_event *old, 335 struct v4l2_event *new) 336 { 337 new->u.src_change.changes |= old->u.src_change.changes; 338 } 339 340 static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = { 341 .replace = v4l2_event_src_replace, 342 .merge = v4l2_event_src_merge, 343 }; 344 345 int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, 346 const struct v4l2_event_subscription *sub) 347 { 348 if (sub->type == V4L2_EVENT_SOURCE_CHANGE) 349 return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops); 350 return -EINVAL; 351 } 352 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe); 353 354 int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, 355 struct v4l2_fh *fh, struct v4l2_event_subscription *sub) 356 { 357 return v4l2_src_change_event_subscribe(fh, sub); 358 } 359 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe); 360