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 20 #include <media/v4l2-dev.h> 21 #include <media/v4l2-fh.h> 22 #include <media/v4l2-event.h> 23 24 #include <linux/sched.h> 25 #include <linux/slab.h> 26 #include <linux/export.h> 27 28 static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx) 29 { 30 idx += sev->first; 31 return idx >= sev->elems ? idx - sev->elems : idx; 32 } 33 34 static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event) 35 { 36 struct v4l2_kevent *kev; 37 unsigned long flags; 38 39 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 40 41 if (list_empty(&fh->available)) { 42 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 43 return -ENOENT; 44 } 45 46 WARN_ON(fh->navailable == 0); 47 48 kev = list_first_entry(&fh->available, struct v4l2_kevent, list); 49 list_del(&kev->list); 50 fh->navailable--; 51 52 kev->event.pending = fh->navailable; 53 *event = kev->event; 54 kev->sev->first = sev_pos(kev->sev, 1); 55 kev->sev->in_use--; 56 57 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 58 59 return 0; 60 } 61 62 int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event, 63 int nonblocking) 64 { 65 int ret; 66 67 if (nonblocking) 68 return __v4l2_event_dequeue(fh, event); 69 70 /* Release the vdev lock while waiting */ 71 if (fh->vdev->lock) 72 mutex_unlock(fh->vdev->lock); 73 74 do { 75 ret = wait_event_interruptible(fh->wait, 76 fh->navailable != 0); 77 if (ret < 0) 78 break; 79 80 ret = __v4l2_event_dequeue(fh, event); 81 } while (ret == -ENOENT); 82 83 if (fh->vdev->lock) 84 mutex_lock(fh->vdev->lock); 85 86 return ret; 87 } 88 EXPORT_SYMBOL_GPL(v4l2_event_dequeue); 89 90 /* Caller must hold fh->vdev->fh_lock! */ 91 static struct v4l2_subscribed_event *v4l2_event_subscribed( 92 struct v4l2_fh *fh, u32 type, u32 id) 93 { 94 struct v4l2_subscribed_event *sev; 95 96 assert_spin_locked(&fh->vdev->fh_lock); 97 98 list_for_each_entry(sev, &fh->subscribed, list) 99 if (sev->type == type && sev->id == id) 100 return sev; 101 102 return NULL; 103 } 104 105 static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev, 106 const struct timespec *ts) 107 { 108 struct v4l2_subscribed_event *sev; 109 struct v4l2_kevent *kev; 110 bool copy_payload = true; 111 112 /* Are we subscribed? */ 113 sev = v4l2_event_subscribed(fh, ev->type, ev->id); 114 if (sev == NULL) 115 return; 116 117 /* 118 * If the event has been added to the fh->subscribed list, but its 119 * add op has not completed yet elems will be 0, treat this as 120 * not being subscribed. 121 */ 122 if (!sev->elems) 123 return; 124 125 /* Increase event sequence number on fh. */ 126 fh->sequence++; 127 128 /* Do we have any free events? */ 129 if (sev->in_use == sev->elems) { 130 /* no, remove the oldest one */ 131 kev = sev->events + sev_pos(sev, 0); 132 list_del(&kev->list); 133 sev->in_use--; 134 sev->first = sev_pos(sev, 1); 135 fh->navailable--; 136 if (sev->elems == 1) { 137 if (sev->ops && sev->ops->replace) { 138 sev->ops->replace(&kev->event, ev); 139 copy_payload = false; 140 } 141 } else if (sev->ops && sev->ops->merge) { 142 struct v4l2_kevent *second_oldest = 143 sev->events + sev_pos(sev, 0); 144 sev->ops->merge(&kev->event, &second_oldest->event); 145 } 146 } 147 148 /* Take one and fill it. */ 149 kev = sev->events + sev_pos(sev, sev->in_use); 150 kev->event.type = ev->type; 151 if (copy_payload) 152 kev->event.u = ev->u; 153 kev->event.id = ev->id; 154 kev->event.timestamp = *ts; 155 kev->event.sequence = fh->sequence; 156 sev->in_use++; 157 list_add_tail(&kev->list, &fh->available); 158 159 fh->navailable++; 160 161 wake_up_all(&fh->wait); 162 } 163 164 void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev) 165 { 166 struct v4l2_fh *fh; 167 unsigned long flags; 168 struct timespec timestamp; 169 170 if (vdev == NULL) 171 return; 172 173 ktime_get_ts(×tamp); 174 175 spin_lock_irqsave(&vdev->fh_lock, flags); 176 177 list_for_each_entry(fh, &vdev->fh_list, list) 178 __v4l2_event_queue_fh(fh, ev, ×tamp); 179 180 spin_unlock_irqrestore(&vdev->fh_lock, flags); 181 } 182 EXPORT_SYMBOL_GPL(v4l2_event_queue); 183 184 void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev) 185 { 186 unsigned long flags; 187 struct timespec timestamp; 188 189 ktime_get_ts(×tamp); 190 191 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 192 __v4l2_event_queue_fh(fh, ev, ×tamp); 193 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 194 } 195 EXPORT_SYMBOL_GPL(v4l2_event_queue_fh); 196 197 int v4l2_event_pending(struct v4l2_fh *fh) 198 { 199 return fh->navailable; 200 } 201 EXPORT_SYMBOL_GPL(v4l2_event_pending); 202 203 int v4l2_event_subscribe(struct v4l2_fh *fh, 204 const struct v4l2_event_subscription *sub, unsigned elems, 205 const struct v4l2_subscribed_event_ops *ops) 206 { 207 struct v4l2_subscribed_event *sev, *found_ev; 208 unsigned long flags; 209 unsigned i; 210 211 if (sub->type == V4L2_EVENT_ALL) 212 return -EINVAL; 213 214 if (elems < 1) 215 elems = 1; 216 217 sev = kzalloc(sizeof(*sev) + sizeof(struct v4l2_kevent) * elems, GFP_KERNEL); 218 if (!sev) 219 return -ENOMEM; 220 for (i = 0; i < elems; i++) 221 sev->events[i].sev = sev; 222 sev->type = sub->type; 223 sev->id = sub->id; 224 sev->flags = sub->flags; 225 sev->fh = fh; 226 sev->ops = ops; 227 228 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 229 found_ev = v4l2_event_subscribed(fh, sub->type, sub->id); 230 if (!found_ev) 231 list_add(&sev->list, &fh->subscribed); 232 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 233 234 if (found_ev) { 235 kfree(sev); 236 return 0; /* Already listening */ 237 } 238 239 if (sev->ops && sev->ops->add) { 240 int ret = sev->ops->add(sev, elems); 241 if (ret) { 242 sev->ops = NULL; 243 v4l2_event_unsubscribe(fh, sub); 244 return ret; 245 } 246 } 247 248 /* Mark as ready for use */ 249 sev->elems = elems; 250 251 return 0; 252 } 253 EXPORT_SYMBOL_GPL(v4l2_event_subscribe); 254 255 void v4l2_event_unsubscribe_all(struct v4l2_fh *fh) 256 { 257 struct v4l2_event_subscription sub; 258 struct v4l2_subscribed_event *sev; 259 unsigned long flags; 260 261 do { 262 sev = NULL; 263 264 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 265 if (!list_empty(&fh->subscribed)) { 266 sev = list_first_entry(&fh->subscribed, 267 struct v4l2_subscribed_event, list); 268 sub.type = sev->type; 269 sub.id = sev->id; 270 } 271 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 272 if (sev) 273 v4l2_event_unsubscribe(fh, &sub); 274 } while (sev); 275 } 276 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe_all); 277 278 int v4l2_event_unsubscribe(struct v4l2_fh *fh, 279 const struct v4l2_event_subscription *sub) 280 { 281 struct v4l2_subscribed_event *sev; 282 unsigned long flags; 283 int i; 284 285 if (sub->type == V4L2_EVENT_ALL) { 286 v4l2_event_unsubscribe_all(fh); 287 return 0; 288 } 289 290 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 291 292 sev = v4l2_event_subscribed(fh, sub->type, sub->id); 293 if (sev != NULL) { 294 /* Remove any pending events for this subscription */ 295 for (i = 0; i < sev->in_use; i++) { 296 list_del(&sev->events[sev_pos(sev, i)].list); 297 fh->navailable--; 298 } 299 list_del(&sev->list); 300 } 301 302 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 303 304 if (sev && sev->ops && sev->ops->del) 305 sev->ops->del(sev); 306 307 kfree(sev); 308 309 return 0; 310 } 311 EXPORT_SYMBOL_GPL(v4l2_event_unsubscribe); 312 313 int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh *fh, 314 struct v4l2_event_subscription *sub) 315 { 316 return v4l2_event_unsubscribe(fh, sub); 317 } 318 EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe); 319 320 static void v4l2_event_src_replace(struct v4l2_event *old, 321 const struct v4l2_event *new) 322 { 323 u32 old_changes = old->u.src_change.changes; 324 325 old->u.src_change = new->u.src_change; 326 old->u.src_change.changes |= old_changes; 327 } 328 329 static void v4l2_event_src_merge(const struct v4l2_event *old, 330 struct v4l2_event *new) 331 { 332 new->u.src_change.changes |= old->u.src_change.changes; 333 } 334 335 static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = { 336 .replace = v4l2_event_src_replace, 337 .merge = v4l2_event_src_merge, 338 }; 339 340 int v4l2_src_change_event_subscribe(struct v4l2_fh *fh, 341 const struct v4l2_event_subscription *sub) 342 { 343 if (sub->type == V4L2_EVENT_SOURCE_CHANGE) 344 return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops); 345 return -EINVAL; 346 } 347 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe); 348 349 int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd, 350 struct v4l2_fh *fh, struct v4l2_event_subscription *sub) 351 { 352 return v4l2_src_change_event_subscribe(fh, sub); 353 } 354 EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe); 355