1 /* 2 * V4L2 asynchronous subdevice registration API 3 * 4 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <linux/device.h> 12 #include <linux/err.h> 13 #include <linux/i2c.h> 14 #include <linux/list.h> 15 #include <linux/mm.h> 16 #include <linux/module.h> 17 #include <linux/mutex.h> 18 #include <linux/of.h> 19 #include <linux/platform_device.h> 20 #include <linux/slab.h> 21 #include <linux/types.h> 22 23 #include <media/v4l2-async.h> 24 #include <media/v4l2-device.h> 25 #include <media/v4l2-fwnode.h> 26 #include <media/v4l2-subdev.h> 27 28 static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n, 29 struct v4l2_subdev *subdev, 30 struct v4l2_async_subdev *asd) 31 { 32 if (!n->ops || !n->ops->bound) 33 return 0; 34 35 return n->ops->bound(n, subdev, asd); 36 } 37 38 static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n, 39 struct v4l2_subdev *subdev, 40 struct v4l2_async_subdev *asd) 41 { 42 if (!n->ops || !n->ops->unbind) 43 return; 44 45 n->ops->unbind(n, subdev, asd); 46 } 47 48 static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n) 49 { 50 if (!n->ops || !n->ops->complete) 51 return 0; 52 53 return n->ops->complete(n); 54 } 55 56 static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) 57 { 58 #if IS_ENABLED(CONFIG_I2C) 59 struct i2c_client *client = i2c_verify_client(sd->dev); 60 return client && 61 asd->match.i2c.adapter_id == client->adapter->nr && 62 asd->match.i2c.address == client->addr; 63 #else 64 return false; 65 #endif 66 } 67 68 static bool match_devname(struct v4l2_subdev *sd, 69 struct v4l2_async_subdev *asd) 70 { 71 return !strcmp(asd->match.device_name, dev_name(sd->dev)); 72 } 73 74 static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) 75 { 76 return sd->fwnode == asd->match.fwnode; 77 } 78 79 static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) 80 { 81 if (!asd->match.custom.match) 82 /* Match always */ 83 return true; 84 85 return asd->match.custom.match(sd->dev, asd); 86 } 87 88 static LIST_HEAD(subdev_list); 89 static LIST_HEAD(notifier_list); 90 static DEFINE_MUTEX(list_lock); 91 92 static struct v4l2_async_subdev *v4l2_async_find_match( 93 struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd) 94 { 95 bool (*match)(struct v4l2_subdev *, struct v4l2_async_subdev *); 96 struct v4l2_async_subdev *asd; 97 98 list_for_each_entry(asd, ¬ifier->waiting, list) { 99 /* bus_type has been verified valid before */ 100 switch (asd->match_type) { 101 case V4L2_ASYNC_MATCH_CUSTOM: 102 match = match_custom; 103 break; 104 case V4L2_ASYNC_MATCH_DEVNAME: 105 match = match_devname; 106 break; 107 case V4L2_ASYNC_MATCH_I2C: 108 match = match_i2c; 109 break; 110 case V4L2_ASYNC_MATCH_FWNODE: 111 match = match_fwnode; 112 break; 113 default: 114 /* Cannot happen, unless someone breaks us */ 115 WARN_ON(true); 116 return NULL; 117 } 118 119 /* match cannot be NULL here */ 120 if (match(sd, asd)) 121 return asd; 122 } 123 124 return NULL; 125 } 126 127 /* Find the sub-device notifier registered by a sub-device driver. */ 128 static struct v4l2_async_notifier *v4l2_async_find_subdev_notifier( 129 struct v4l2_subdev *sd) 130 { 131 struct v4l2_async_notifier *n; 132 133 list_for_each_entry(n, ¬ifier_list, list) 134 if (n->sd == sd) 135 return n; 136 137 return NULL; 138 } 139 140 /* Get v4l2_device related to the notifier if one can be found. */ 141 static struct v4l2_device *v4l2_async_notifier_find_v4l2_dev( 142 struct v4l2_async_notifier *notifier) 143 { 144 while (notifier->parent) 145 notifier = notifier->parent; 146 147 return notifier->v4l2_dev; 148 } 149 150 /* 151 * Return true if all child sub-device notifiers are complete, false otherwise. 152 */ 153 static bool v4l2_async_notifier_can_complete( 154 struct v4l2_async_notifier *notifier) 155 { 156 struct v4l2_subdev *sd; 157 158 if (!list_empty(¬ifier->waiting)) 159 return false; 160 161 list_for_each_entry(sd, ¬ifier->done, async_list) { 162 struct v4l2_async_notifier *subdev_notifier = 163 v4l2_async_find_subdev_notifier(sd); 164 165 if (subdev_notifier && 166 !v4l2_async_notifier_can_complete(subdev_notifier)) 167 return false; 168 } 169 170 return true; 171 } 172 173 /* 174 * Complete the master notifier if possible. This is done when all async 175 * sub-devices have been bound; v4l2_device is also available then. 176 */ 177 static int v4l2_async_notifier_try_complete( 178 struct v4l2_async_notifier *notifier) 179 { 180 /* Quick check whether there are still more sub-devices here. */ 181 if (!list_empty(¬ifier->waiting)) 182 return 0; 183 184 /* Check the entire notifier tree; find the root notifier first. */ 185 while (notifier->parent) 186 notifier = notifier->parent; 187 188 /* This is root if it has v4l2_dev. */ 189 if (!notifier->v4l2_dev) 190 return 0; 191 192 /* Is everything ready? */ 193 if (!v4l2_async_notifier_can_complete(notifier)) 194 return 0; 195 196 return v4l2_async_notifier_call_complete(notifier); 197 } 198 199 static int v4l2_async_notifier_try_all_subdevs( 200 struct v4l2_async_notifier *notifier); 201 202 static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier, 203 struct v4l2_device *v4l2_dev, 204 struct v4l2_subdev *sd, 205 struct v4l2_async_subdev *asd) 206 { 207 struct v4l2_async_notifier *subdev_notifier; 208 int ret; 209 210 ret = v4l2_device_register_subdev(v4l2_dev, sd); 211 if (ret < 0) 212 return ret; 213 214 ret = v4l2_async_notifier_call_bound(notifier, sd, asd); 215 if (ret < 0) { 216 v4l2_device_unregister_subdev(sd); 217 return ret; 218 } 219 220 /* Remove from the waiting list */ 221 list_del(&asd->list); 222 sd->asd = asd; 223 sd->notifier = notifier; 224 225 /* Move from the global subdevice list to notifier's done */ 226 list_move(&sd->async_list, ¬ifier->done); 227 228 /* 229 * See if the sub-device has a notifier. If not, return here. 230 */ 231 subdev_notifier = v4l2_async_find_subdev_notifier(sd); 232 if (!subdev_notifier || subdev_notifier->parent) 233 return 0; 234 235 /* 236 * Proceed with checking for the sub-device notifier's async 237 * sub-devices, and return the result. The error will be handled by the 238 * caller. 239 */ 240 subdev_notifier->parent = notifier; 241 242 return v4l2_async_notifier_try_all_subdevs(subdev_notifier); 243 } 244 245 /* Test all async sub-devices in a notifier for a match. */ 246 static int v4l2_async_notifier_try_all_subdevs( 247 struct v4l2_async_notifier *notifier) 248 { 249 struct v4l2_device *v4l2_dev = 250 v4l2_async_notifier_find_v4l2_dev(notifier); 251 struct v4l2_subdev *sd; 252 253 if (!v4l2_dev) 254 return 0; 255 256 again: 257 list_for_each_entry(sd, &subdev_list, async_list) { 258 struct v4l2_async_subdev *asd; 259 int ret; 260 261 asd = v4l2_async_find_match(notifier, sd); 262 if (!asd) 263 continue; 264 265 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd); 266 if (ret < 0) 267 return ret; 268 269 /* 270 * v4l2_async_match_notify() may lead to registering a 271 * new notifier and thus changing the async subdevs 272 * list. In order to proceed safely from here, restart 273 * parsing the list from the beginning. 274 */ 275 goto again; 276 } 277 278 return 0; 279 } 280 281 static void v4l2_async_cleanup(struct v4l2_subdev *sd) 282 { 283 v4l2_device_unregister_subdev(sd); 284 /* Subdevice driver will reprobe and put the subdev back onto the list */ 285 list_del_init(&sd->async_list); 286 sd->asd = NULL; 287 } 288 289 /* Unbind all sub-devices in the notifier tree. */ 290 static void v4l2_async_notifier_unbind_all_subdevs( 291 struct v4l2_async_notifier *notifier) 292 { 293 struct v4l2_subdev *sd, *tmp; 294 295 list_for_each_entry_safe(sd, tmp, ¬ifier->done, async_list) { 296 struct v4l2_async_notifier *subdev_notifier = 297 v4l2_async_find_subdev_notifier(sd); 298 299 if (subdev_notifier) 300 v4l2_async_notifier_unbind_all_subdevs(subdev_notifier); 301 302 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd); 303 v4l2_async_cleanup(sd); 304 305 list_move(&sd->async_list, &subdev_list); 306 } 307 308 notifier->parent = NULL; 309 } 310 311 /* See if an fwnode can be found in a notifier's lists. */ 312 static bool __v4l2_async_notifier_fwnode_has_async_subdev( 313 struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode) 314 { 315 struct v4l2_async_subdev *asd; 316 struct v4l2_subdev *sd; 317 318 list_for_each_entry(asd, ¬ifier->waiting, list) { 319 if (asd->match_type != V4L2_ASYNC_MATCH_FWNODE) 320 continue; 321 322 if (asd->match.fwnode == fwnode) 323 return true; 324 } 325 326 list_for_each_entry(sd, ¬ifier->done, async_list) { 327 if (WARN_ON(!sd->asd)) 328 continue; 329 330 if (sd->asd->match_type != V4L2_ASYNC_MATCH_FWNODE) 331 continue; 332 333 if (sd->asd->match.fwnode == fwnode) 334 return true; 335 } 336 337 return false; 338 } 339 340 /* 341 * Find out whether an async sub-device was set up for an fwnode already or 342 * whether it exists in a given notifier before @this_index. 343 */ 344 static bool v4l2_async_notifier_fwnode_has_async_subdev( 345 struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode, 346 unsigned int this_index) 347 { 348 unsigned int j; 349 350 lockdep_assert_held(&list_lock); 351 352 /* Check that an fwnode is not being added more than once. */ 353 for (j = 0; j < this_index; j++) { 354 struct v4l2_async_subdev *asd = notifier->subdevs[this_index]; 355 struct v4l2_async_subdev *other_asd = notifier->subdevs[j]; 356 357 if (other_asd->match_type == V4L2_ASYNC_MATCH_FWNODE && 358 asd->match.fwnode == 359 other_asd->match.fwnode) 360 return true; 361 } 362 363 /* Check than an fwnode did not exist in other notifiers. */ 364 list_for_each_entry(notifier, ¬ifier_list, list) 365 if (__v4l2_async_notifier_fwnode_has_async_subdev( 366 notifier, fwnode)) 367 return true; 368 369 return false; 370 } 371 372 static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier) 373 { 374 struct device *dev = 375 notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL; 376 struct v4l2_async_subdev *asd; 377 int ret; 378 int i; 379 380 if (notifier->num_subdevs > V4L2_MAX_SUBDEVS) 381 return -EINVAL; 382 383 INIT_LIST_HEAD(¬ifier->waiting); 384 INIT_LIST_HEAD(¬ifier->done); 385 386 mutex_lock(&list_lock); 387 388 for (i = 0; i < notifier->num_subdevs; i++) { 389 asd = notifier->subdevs[i]; 390 391 switch (asd->match_type) { 392 case V4L2_ASYNC_MATCH_CUSTOM: 393 case V4L2_ASYNC_MATCH_DEVNAME: 394 case V4L2_ASYNC_MATCH_I2C: 395 break; 396 case V4L2_ASYNC_MATCH_FWNODE: 397 if (v4l2_async_notifier_fwnode_has_async_subdev( 398 notifier, asd->match.fwnode, i)) { 399 dev_err(dev, 400 "fwnode has already been registered or in notifier's subdev list\n"); 401 ret = -EEXIST; 402 goto err_unlock; 403 } 404 break; 405 default: 406 dev_err(dev, "Invalid match type %u on %p\n", 407 asd->match_type, asd); 408 ret = -EINVAL; 409 goto err_unlock; 410 } 411 list_add_tail(&asd->list, ¬ifier->waiting); 412 } 413 414 ret = v4l2_async_notifier_try_all_subdevs(notifier); 415 if (ret < 0) 416 goto err_unbind; 417 418 ret = v4l2_async_notifier_try_complete(notifier); 419 if (ret < 0) 420 goto err_unbind; 421 422 /* Keep also completed notifiers on the list */ 423 list_add(¬ifier->list, ¬ifier_list); 424 425 mutex_unlock(&list_lock); 426 427 return 0; 428 429 err_unbind: 430 /* 431 * On failure, unbind all sub-devices registered through this notifier. 432 */ 433 v4l2_async_notifier_unbind_all_subdevs(notifier); 434 435 err_unlock: 436 mutex_unlock(&list_lock); 437 438 return ret; 439 } 440 441 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, 442 struct v4l2_async_notifier *notifier) 443 { 444 int ret; 445 446 if (WARN_ON(!v4l2_dev || notifier->sd)) 447 return -EINVAL; 448 449 notifier->v4l2_dev = v4l2_dev; 450 451 ret = __v4l2_async_notifier_register(notifier); 452 if (ret) 453 notifier->v4l2_dev = NULL; 454 455 return ret; 456 } 457 EXPORT_SYMBOL(v4l2_async_notifier_register); 458 459 int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd, 460 struct v4l2_async_notifier *notifier) 461 { 462 int ret; 463 464 if (WARN_ON(!sd || notifier->v4l2_dev)) 465 return -EINVAL; 466 467 notifier->sd = sd; 468 469 ret = __v4l2_async_notifier_register(notifier); 470 if (ret) 471 notifier->sd = NULL; 472 473 return ret; 474 } 475 EXPORT_SYMBOL(v4l2_async_subdev_notifier_register); 476 477 static void __v4l2_async_notifier_unregister( 478 struct v4l2_async_notifier *notifier) 479 { 480 if (!notifier || (!notifier->v4l2_dev && !notifier->sd)) 481 return; 482 483 v4l2_async_notifier_unbind_all_subdevs(notifier); 484 485 notifier->sd = NULL; 486 notifier->v4l2_dev = NULL; 487 488 list_del(¬ifier->list); 489 } 490 491 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier) 492 { 493 mutex_lock(&list_lock); 494 495 __v4l2_async_notifier_unregister(notifier); 496 497 mutex_unlock(&list_lock); 498 } 499 EXPORT_SYMBOL(v4l2_async_notifier_unregister); 500 501 void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier) 502 { 503 unsigned int i; 504 505 if (!notifier || !notifier->max_subdevs) 506 return; 507 508 for (i = 0; i < notifier->num_subdevs; i++) { 509 struct v4l2_async_subdev *asd = notifier->subdevs[i]; 510 511 switch (asd->match_type) { 512 case V4L2_ASYNC_MATCH_FWNODE: 513 fwnode_handle_put(asd->match.fwnode); 514 break; 515 default: 516 WARN_ON_ONCE(true); 517 break; 518 } 519 520 kfree(asd); 521 } 522 523 notifier->max_subdevs = 0; 524 notifier->num_subdevs = 0; 525 526 kvfree(notifier->subdevs); 527 notifier->subdevs = NULL; 528 } 529 EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup); 530 531 int v4l2_async_register_subdev(struct v4l2_subdev *sd) 532 { 533 struct v4l2_async_notifier *subdev_notifier; 534 struct v4l2_async_notifier *notifier; 535 int ret; 536 537 /* 538 * No reference taken. The reference is held by the device 539 * (struct v4l2_subdev.dev), and async sub-device does not 540 * exist independently of the device at any point of time. 541 */ 542 if (!sd->fwnode && sd->dev) 543 sd->fwnode = dev_fwnode(sd->dev); 544 545 mutex_lock(&list_lock); 546 547 INIT_LIST_HEAD(&sd->async_list); 548 549 list_for_each_entry(notifier, ¬ifier_list, list) { 550 struct v4l2_device *v4l2_dev = 551 v4l2_async_notifier_find_v4l2_dev(notifier); 552 struct v4l2_async_subdev *asd; 553 554 if (!v4l2_dev) 555 continue; 556 557 asd = v4l2_async_find_match(notifier, sd); 558 if (!asd) 559 continue; 560 561 ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd); 562 if (ret) 563 goto err_unbind; 564 565 ret = v4l2_async_notifier_try_complete(notifier); 566 if (ret) 567 goto err_unbind; 568 569 goto out_unlock; 570 } 571 572 /* None matched, wait for hot-plugging */ 573 list_add(&sd->async_list, &subdev_list); 574 575 out_unlock: 576 mutex_unlock(&list_lock); 577 578 return 0; 579 580 err_unbind: 581 /* 582 * Complete failed. Unbind the sub-devices bound through registering 583 * this async sub-device. 584 */ 585 subdev_notifier = v4l2_async_find_subdev_notifier(sd); 586 if (subdev_notifier) 587 v4l2_async_notifier_unbind_all_subdevs(subdev_notifier); 588 589 if (sd->asd) 590 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd); 591 v4l2_async_cleanup(sd); 592 593 mutex_unlock(&list_lock); 594 595 return ret; 596 } 597 EXPORT_SYMBOL(v4l2_async_register_subdev); 598 599 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd) 600 { 601 mutex_lock(&list_lock); 602 603 __v4l2_async_notifier_unregister(sd->subdev_notifier); 604 v4l2_async_notifier_cleanup(sd->subdev_notifier); 605 kfree(sd->subdev_notifier); 606 sd->subdev_notifier = NULL; 607 608 if (sd->asd) { 609 struct v4l2_async_notifier *notifier = sd->notifier; 610 611 list_add(&sd->asd->list, ¬ifier->waiting); 612 613 v4l2_async_notifier_call_unbind(notifier, sd, sd->asd); 614 } 615 616 v4l2_async_cleanup(sd); 617 618 mutex_unlock(&list_lock); 619 } 620 EXPORT_SYMBOL(v4l2_async_unregister_subdev); 621