drivers/media/media-entity.c

   1 /*
   2  * Media entity
   3  *
   4  * Copyright (C) 2010 Nokia Corporation
   5  *
   6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   7  *           Sakari Ailus <sakari.ailus@iki.fi>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/bitmap.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <media/media-entity.h>
  27 #include <media/media-device.h>
  28
  29 static inline const char *gobj_type(enum media_gobj_type type)
  30 {
  31         switch (type) {
  32         case MEDIA_GRAPH_ENTITY:
  33                 return "entity";
  34         case MEDIA_GRAPH_PAD:
  35                 return "pad";
  36         case MEDIA_GRAPH_LINK:
  37                 return "link";
  38         case MEDIA_GRAPH_INTF_DEVNODE:
  39                 return "intf-devnode";
  40         default:
  41                 return "unknown";
  42         }
  43 }
  44
  45 static inline const char *intf_type(struct media_interface *intf)
  46 {
  47         switch (intf->type) {
  48         case MEDIA_INTF_T_DVB_FE:
  49                 return "frontend";
  50         case MEDIA_INTF_T_DVB_DEMUX:
  51                 return "demux";
  52         case MEDIA_INTF_T_DVB_DVR:
  53                 return "DVR";
  54         case MEDIA_INTF_T_DVB_CA:
  55                 return  "CA";
  56         case MEDIA_INTF_T_DVB_NET:
  57                 return "dvbnet";
  58         case MEDIA_INTF_T_V4L_VIDEO:
  59                 return "video";
  60         case MEDIA_INTF_T_V4L_VBI:
  61                 return "vbi";
  62         case MEDIA_INTF_T_V4L_RADIO:
  63                 return "radio";
  64         case MEDIA_INTF_T_V4L_SUBDEV:
  65                 return "v4l2-subdev";
  66         case MEDIA_INTF_T_V4L_SWRADIO:
  67                 return "swradio";
  68         default:
  69                 return "unknown-intf";
  70         }
  71 };
  72
  73 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  74                                           int idx_max)
  75 {
  76         ent_enum->bmap = kcalloc(DIV_ROUND_UP(idx_max, BITS_PER_LONG),
  77                                  sizeof(long), GFP_KERNEL);
  78         if (!ent_enum->bmap)
  79                 return -ENOMEM;
  80
  81         bitmap_zero(ent_enum->bmap, idx_max);
  82         ent_enum->idx_max = idx_max;
  83
  84         return 0;
  85 }
  86 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
  87
  88 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
  89 {
  90         kfree(ent_enum->bmap);
  91 }
  92 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
  93
  94 /**
  95  *  dev_dbg_obj - Prints in debug mode a change on some object
  96  *
  97  * @event_name: Name of the event to report. Could be __func__
  98  * @gobj:       Pointer to the object
  99  *
 100  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 101  * won't produce any code.
 102  */
 103 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 104 {
 105 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 106         switch (media_type(gobj)) {
 107         case MEDIA_GRAPH_ENTITY:
 108                 dev_dbg(gobj->mdev->dev,
 109                         "%s id %u: entity '%s'\n",
 110                         event_name, media_id(gobj),
 111                         gobj_to_entity(gobj)->name);
 112                 break;
 113         case MEDIA_GRAPH_LINK:
 114         {
 115                 struct media_link *link = gobj_to_link(gobj);
 116
 117                 dev_dbg(gobj->mdev->dev,
 118                         "%s id %u: %s link id %u ==> id %u\n",
 119                         event_name, media_id(gobj),
 120                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 121                                 "data" : "interface",
 122                         media_id(link->gobj0),
 123                         media_id(link->gobj1));
 124                 break;
 125         }
 126         case MEDIA_GRAPH_PAD:
 127         {
 128                 struct media_pad *pad = gobj_to_pad(gobj);
 129
 130                 dev_dbg(gobj->mdev->dev,
 131                         "%s id %u: %s%spad '%s':%d\n",
 132                         event_name, media_id(gobj),
 133                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 134                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 135                         pad->entity->name, pad->index);
 136                 break;
 137         }
 138         case MEDIA_GRAPH_INTF_DEVNODE:
 139         {
 140                 struct media_interface *intf = gobj_to_intf(gobj);
 141                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 142
 143                 dev_dbg(gobj->mdev->dev,
 144                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 145                         event_name, media_id(gobj),
 146                         intf_type(intf),
 147                         devnode->major, devnode->minor);
 148                 break;
 149         }
 150         }
 151 #endif
 152 }
 153
 154 void media_gobj_create(struct media_device *mdev,
 155                            enum media_gobj_type type,
 156                            struct media_gobj *gobj)
 157 {
 158         BUG_ON(!mdev);
 159
 160         gobj->mdev = mdev;
 161
 162         /* Create a per-type unique object ID */
 163         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 164
 165         switch (type) {
 166         case MEDIA_GRAPH_ENTITY:
 167                 list_add_tail(&gobj->list, &mdev->entities);
 168                 break;
 169         case MEDIA_GRAPH_PAD:
 170                 list_add_tail(&gobj->list, &mdev->pads);
 171                 break;
 172         case MEDIA_GRAPH_LINK:
 173                 list_add_tail(&gobj->list, &mdev->links);
 174                 break;
 175         case MEDIA_GRAPH_INTF_DEVNODE:
 176                 list_add_tail(&gobj->list, &mdev->interfaces);
 177                 break;
 178         }
 179
 180         mdev->topology_version++;
 181
 182         dev_dbg_obj(__func__, gobj);
 183 }
 184
 185 void media_gobj_destroy(struct media_gobj *gobj)
 186 {
 187         dev_dbg_obj(__func__, gobj);
 188
 189         gobj->mdev->topology_version++;
 190
 191         /* Remove the object from mdev list */
 192         list_del(&gobj->list);
 193 }
 194
 195 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 196                            struct media_pad *pads)
 197 {
 198         struct media_device *mdev = entity->graph_obj.mdev;
 199         unsigned int i;
 200
 201         entity->num_pads = num_pads;
 202         entity->pads = pads;
 203
 204         if (mdev)
 205                 spin_lock(&mdev->lock);
 206
 207         for (i = 0; i < num_pads; i++) {
 208                 pads[i].entity = entity;
 209                 pads[i].index = i;
 210                 if (mdev)
 211                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 212                                         &entity->pads[i].graph_obj);
 213         }
 214
 215         if (mdev)
 216                 spin_unlock(&mdev->lock);
 217
 218         return 0;
 219 }
 220 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 221
 222 /* -----------------------------------------------------------------------------
 223  * Graph traversal
 224  */
 225
 226 static struct media_entity *
 227 media_entity_other(struct media_entity *entity, struct media_link *link)
 228 {
 229         if (link->source->entity == entity)
 230                 return link->sink->entity;
 231         else
 232                 return link->source->entity;
 233 }
 234
 235 /* push an entity to traversal stack */
 236 static void stack_push(struct media_entity_graph *graph,
 237                        struct media_entity *entity)
 238 {
 239         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 240                 WARN_ON(1);
 241                 return;
 242         }
 243         graph->top++;
 244         graph->stack[graph->top].link = entity->links.next;
 245         graph->stack[graph->top].entity = entity;
 246 }
 247
 248 static struct media_entity *stack_pop(struct media_entity_graph *graph)
 249 {
 250         struct media_entity *entity;
 251
 252         entity = graph->stack[graph->top].entity;
 253         graph->top--;
 254
 255         return entity;
 256 }
 257
 258 #define link_top(en)    ((en)->stack[(en)->top].link)
 259 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 260
 261 /*
 262  * TODO: Get rid of this.
 263  */
 264 #define MEDIA_ENTITY_MAX_PADS           512
 265
 266 /**
 267  * media_entity_graph_walk_init - Allocate resources for graph walk
 268  * @graph: Media graph structure that will be used to walk the graph
 269  * @mdev: Media device
 270  *
 271  * Reserve resources for graph walk in media device's current
 272  * state. The memory must be released using
 273  * media_entity_graph_walk_free().
 274  *
 275  * Returns error on failure, zero on success.
 276  */
 277 __must_check int media_entity_graph_walk_init(
 278         struct media_entity_graph *graph, struct media_device *mdev)
 279 {
 280         return media_entity_enum_init(&graph->ent_enum, mdev);
 281 }
 282 EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
 283
 284 /**
 285  * media_entity_graph_walk_cleanup - Release resources related to graph walking
 286  * @graph: Media graph structure that was used to walk the graph
 287  */
 288 void media_entity_graph_walk_cleanup(struct media_entity_graph *graph)
 289 {
 290         media_entity_enum_cleanup(&graph->ent_enum);
 291 }
 292 EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
 293
 294 void media_entity_graph_walk_start(struct media_entity_graph *graph,
 295                                    struct media_entity *entity)
 296 {
 297         media_entity_enum_zero(&graph->ent_enum);
 298         media_entity_enum_set(&graph->ent_enum, entity);
 299
 300         graph->top = 0;
 301         graph->stack[graph->top].entity = NULL;
 302         stack_push(graph, entity);
 303 }
 304 EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
 305
 306 struct media_entity *
 307 media_entity_graph_walk_next(struct media_entity_graph *graph)
 308 {
 309         if (stack_top(graph) == NULL)
 310                 return NULL;
 311
 312         /*
 313          * Depth first search. Push entity to stack and continue from
 314          * top of the stack until no more entities on the level can be
 315          * found.
 316          */
 317         while (link_top(graph) != &stack_top(graph)->links) {
 318                 struct media_entity *entity = stack_top(graph);
 319                 struct media_link *link;
 320                 struct media_entity *next;
 321
 322                 link = list_entry(link_top(graph), typeof(*link), list);
 323
 324                 /* The link is not enabled so we do not follow. */
 325                 if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 326                         link_top(graph) = link_top(graph)->next;
 327                         continue;
 328                 }
 329
 330                 /* Get the entity in the other end of the link . */
 331                 next = media_entity_other(entity, link);
 332
 333                 /* Has the entity already been visited? */
 334                 if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 335                         link_top(graph) = link_top(graph)->next;
 336                         continue;
 337                 }
 338
 339                 /* Push the new entity to stack and start over. */
 340                 link_top(graph) = link_top(graph)->next;
 341                 stack_push(graph, next);
 342         }
 343
 344         return stack_pop(graph);
 345 }
 346 EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
 347
 348 /* -----------------------------------------------------------------------------
 349  * Pipeline management
 350  */
 351
 352 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 353                                              struct media_pipeline *pipe)
 354 {
 355         struct media_device *mdev = entity->graph_obj.mdev;
 356         struct media_entity_graph *graph = &pipe->graph;
 357         struct media_entity *entity_err = entity;
 358         struct media_link *link;
 359         int ret;
 360
 361         mutex_lock(&mdev->graph_mutex);
 362
 363         if (!pipe->streaming_count++) {
 364                 ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 365                 if (ret)
 366                         goto error_graph_walk_start;
 367         }
 368
 369         media_entity_graph_walk_start(&pipe->graph, entity);
 370
 371         while ((entity = media_entity_graph_walk_next(graph))) {
 372                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 373                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 374
 375                 entity->stream_count++;
 376
 377                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 378                         ret = -EBUSY;
 379                         goto error;
 380                 }
 381
 382                 entity->pipe = pipe;
 383
 384                 /* Already streaming --- no need to check. */
 385                 if (entity->stream_count > 1)
 386                         continue;
 387
 388                 if (!entity->ops || !entity->ops->link_validate)
 389                         continue;
 390
 391                 bitmap_zero(active, entity->num_pads);
 392                 bitmap_fill(has_no_links, entity->num_pads);
 393
 394                 list_for_each_entry(link, &entity->links, list) {
 395                         struct media_pad *pad = link->sink->entity == entity
 396                                                 ? link->sink : link->source;
 397
 398                         /* Mark that a pad is connected by a link. */
 399                         bitmap_clear(has_no_links, pad->index, 1);
 400
 401                         /*
 402                          * Pads that either do not need to connect or
 403                          * are connected through an enabled link are
 404                          * fine.
 405                          */
 406                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 407                             link->flags & MEDIA_LNK_FL_ENABLED)
 408                                 bitmap_set(active, pad->index, 1);
 409
 410                         /*
 411                          * Link validation will only take place for
 412                          * sink ends of the link that are enabled.
 413                          */
 414                         if (link->sink != pad ||
 415                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 416                                 continue;
 417
 418                         ret = entity->ops->link_validate(link);
 419                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 420                                 dev_dbg(entity->graph_obj.mdev->dev,
 421                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 422                                         link->source->entity->name,
 423                                         link->source->index,
 424                                         entity->name, link->sink->index, ret);
 425                                 goto error;
 426                         }
 427                 }
 428
 429                 /* Either no links or validated links are fine. */
 430                 bitmap_or(active, active, has_no_links, entity->num_pads);
 431
 432                 if (!bitmap_full(active, entity->num_pads)) {
 433                         ret = -EPIPE;
 434                         dev_dbg(entity->graph_obj.mdev->dev,
 435                                 "\"%s\":%u must be connected by an enabled link\n",
 436                                 entity->name,
 437                                 (unsigned)find_first_zero_bit(
 438                                         active, entity->num_pads));
 439                         goto error;
 440                 }
 441         }
 442
 443         mutex_unlock(&mdev->graph_mutex);
 444
 445         return 0;
 446
 447 error:
 448         /*
 449          * Link validation on graph failed. We revert what we did and
 450          * return the error.
 451          */
 452         media_entity_graph_walk_start(graph, entity_err);
 453
 454         while ((entity_err = media_entity_graph_walk_next(graph))) {
 455                 entity_err->stream_count--;
 456                 if (entity_err->stream_count == 0)
 457                         entity_err->pipe = NULL;
 458
 459                 /*
 460                  * We haven't increased stream_count further than this
 461                  * so we quit here.
 462                  */
 463                 if (entity_err == entity)
 464                         break;
 465         }
 466
 467 error_graph_walk_start:
 468         if (!--pipe->streaming_count)
 469                 media_entity_graph_walk_cleanup(graph);
 470
 471         mutex_unlock(&mdev->graph_mutex);
 472
 473         return ret;
 474 }
 475 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 476
 477 void media_entity_pipeline_stop(struct media_entity *entity)
 478 {
 479         struct media_device *mdev = entity->graph_obj.mdev;
 480         struct media_entity_graph *graph = &entity->pipe->graph;
 481         struct media_pipeline *pipe = entity->pipe;
 482
 483         mutex_lock(&mdev->graph_mutex);
 484
 485         WARN_ON(!pipe->streaming_count);
 486         media_entity_graph_walk_start(graph, entity);
 487
 488         while ((entity = media_entity_graph_walk_next(graph))) {
 489                 entity->stream_count--;
 490                 if (entity->stream_count == 0)
 491                         entity->pipe = NULL;
 492         }
 493
 494         if (!--pipe->streaming_count)
 495                 media_entity_graph_walk_cleanup(graph);
 496
 497         mutex_unlock(&mdev->graph_mutex);
 498 }
 499 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
 500
 501 /* -----------------------------------------------------------------------------
 502  * Module use count
 503  */
 504
 505 struct media_entity *media_entity_get(struct media_entity *entity)
 506 {
 507         if (entity == NULL)
 508                 return NULL;
 509
 510         if (entity->graph_obj.mdev->dev &&
 511             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 512                 return NULL;
 513
 514         return entity;
 515 }
 516 EXPORT_SYMBOL_GPL(media_entity_get);
 517
 518 void media_entity_put(struct media_entity *entity)
 519 {
 520         if (entity == NULL)
 521                 return;
 522
 523         if (entity->graph_obj.mdev->dev)
 524                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 525 }
 526 EXPORT_SYMBOL_GPL(media_entity_put);
 527
 528 /* -----------------------------------------------------------------------------
 529  * Links management
 530  */
 531
 532 static struct media_link *media_add_link(struct list_head *head)
 533 {
 534         struct media_link *link;
 535
 536         link = kzalloc(sizeof(*link), GFP_KERNEL);
 537         if (link == NULL)
 538                 return NULL;
 539
 540         list_add_tail(&link->list, head);
 541
 542         return link;
 543 }
 544
 545 static void __media_entity_remove_link(struct media_entity *entity,
 546                                        struct media_link *link)
 547 {
 548         struct media_link *rlink, *tmp;
 549         struct media_entity *remote;
 550
 551         if (link->source->entity == entity)
 552                 remote = link->sink->entity;
 553         else
 554                 remote = link->source->entity;
 555
 556         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 557                 if (rlink != link->reverse)
 558                         continue;
 559
 560                 if (link->source->entity == entity)
 561                         remote->num_backlinks--;
 562
 563                 /* Remove the remote link */
 564                 list_del(&rlink->list);
 565                 media_gobj_destroy(&rlink->graph_obj);
 566                 kfree(rlink);
 567
 568                 if (--remote->num_links == 0)
 569                         break;
 570         }
 571         list_del(&link->list);
 572         media_gobj_destroy(&link->graph_obj);
 573         kfree(link);
 574 }
 575
 576 int
 577 media_create_pad_link(struct media_entity *source, u16 source_pad,
 578                          struct media_entity *sink, u16 sink_pad, u32 flags)
 579 {
 580         struct media_link *link;
 581         struct media_link *backlink;
 582
 583         BUG_ON(source == NULL || sink == NULL);
 584         BUG_ON(source_pad >= source->num_pads);
 585         BUG_ON(sink_pad >= sink->num_pads);
 586
 587         link = media_add_link(&source->links);
 588         if (link == NULL)
 589                 return -ENOMEM;
 590
 591         link->source = &source->pads[source_pad];
 592         link->sink = &sink->pads[sink_pad];
 593         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 594
 595         /* Initialize graph object embedded at the new link */
 596         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 597                         &link->graph_obj);
 598
 599         /* Create the backlink. Backlinks are used to help graph traversal and
 600          * are not reported to userspace.
 601          */
 602         backlink = media_add_link(&sink->links);
 603         if (backlink == NULL) {
 604                 __media_entity_remove_link(source, link);
 605                 return -ENOMEM;
 606         }
 607
 608         backlink->source = &source->pads[source_pad];
 609         backlink->sink = &sink->pads[sink_pad];
 610         backlink->flags = flags;
 611         backlink->is_backlink = true;
 612
 613         /* Initialize graph object embedded at the new link */
 614         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 615                         &backlink->graph_obj);
 616
 617         link->reverse = backlink;
 618         backlink->reverse = link;
 619
 620         sink->num_backlinks++;
 621         sink->num_links++;
 622         source->num_links++;
 623
 624         return 0;
 625 }
 626 EXPORT_SYMBOL_GPL(media_create_pad_link);
 627
 628 int media_create_pad_links(const struct media_device *mdev,
 629                            const u32 source_function,
 630                            struct media_entity *source,
 631                            const u16 source_pad,
 632                            const u32 sink_function,
 633                            struct media_entity *sink,
 634                            const u16 sink_pad,
 635                            u32 flags,
 636                            const bool allow_both_undefined)
 637 {
 638         struct media_entity *entity;
 639         unsigned function;
 640         int ret;
 641
 642         /* Trivial case: 1:1 relation */
 643         if (source && sink)
 644                 return media_create_pad_link(source, source_pad,
 645                                              sink, sink_pad, flags);
 646
 647         /* Worse case scenario: n:n relation */
 648         if (!source && !sink) {
 649                 if (!allow_both_undefined)
 650                         return 0;
 651                 media_device_for_each_entity(source, mdev) {
 652                         if (source->function != source_function)
 653                                 continue;
 654                         media_device_for_each_entity(sink, mdev) {
 655                                 if (sink->function != sink_function)
 656                                         continue;
 657                                 ret = media_create_pad_link(source, source_pad,
 658                                                             sink, sink_pad,
 659                                                             flags);
 660                                 if (ret)
 661                                         return ret;
 662                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 663                                            MEDIA_LNK_FL_IMMUTABLE);
 664                         }
 665                 }
 666                 return 0;
 667         }
 668
 669         /* Handle 1:n and n:1 cases */
 670         if (source)
 671                 function = sink_function;
 672         else
 673                 function = source_function;
 674
 675         media_device_for_each_entity(entity, mdev) {
 676                 if (entity->function != function)
 677                         continue;
 678
 679                 if (source)
 680                         ret = media_create_pad_link(source, source_pad,
 681                                                     entity, sink_pad, flags);
 682                 else
 683                         ret = media_create_pad_link(entity, source_pad,
 684                                                     sink, sink_pad, flags);
 685                 if (ret)
 686                         return ret;
 687                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 688         }
 689         return 0;
 690 }
 691 EXPORT_SYMBOL_GPL(media_create_pad_links);
 692
 693 void __media_entity_remove_links(struct media_entity *entity)
 694 {
 695         struct media_link *link, *tmp;
 696
 697         list_for_each_entry_safe(link, tmp, &entity->links, list)
 698                 __media_entity_remove_link(entity, link);
 699
 700         entity->num_links = 0;
 701         entity->num_backlinks = 0;
 702 }
 703 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 704
 705 void media_entity_remove_links(struct media_entity *entity)
 706 {
 707         struct media_device *mdev = entity->graph_obj.mdev;
 708
 709         /* Do nothing if the entity is not registered. */
 710         if (mdev == NULL)
 711                 return;
 712
 713         spin_lock(&mdev->lock);
 714         __media_entity_remove_links(entity);
 715         spin_unlock(&mdev->lock);
 716 }
 717 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 718
 719 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 720 {
 721         int ret;
 722
 723         /* Notify both entities. */
 724         ret = media_entity_call(link->source->entity, link_setup,
 725                                 link->source, link->sink, flags);
 726         if (ret < 0 && ret != -ENOIOCTLCMD)
 727                 return ret;
 728
 729         ret = media_entity_call(link->sink->entity, link_setup,
 730                                 link->sink, link->source, flags);
 731         if (ret < 0 && ret != -ENOIOCTLCMD) {
 732                 media_entity_call(link->source->entity, link_setup,
 733                                   link->source, link->sink, link->flags);
 734                 return ret;
 735         }
 736
 737         link->flags = flags;
 738         link->reverse->flags = link->flags;
 739
 740         return 0;
 741 }
 742
 743 int __media_entity_setup_link(struct media_link *link, u32 flags)
 744 {
 745         const u32 mask = MEDIA_LNK_FL_ENABLED;
 746         struct media_device *mdev;
 747         struct media_entity *source, *sink;
 748         int ret = -EBUSY;
 749
 750         if (link == NULL)
 751                 return -EINVAL;
 752
 753         /* The non-modifiable link flags must not be modified. */
 754         if ((link->flags & ~mask) != (flags & ~mask))
 755                 return -EINVAL;
 756
 757         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 758                 return link->flags == flags ? 0 : -EINVAL;
 759
 760         if (link->flags == flags)
 761                 return 0;
 762
 763         source = link->source->entity;
 764         sink = link->sink->entity;
 765
 766         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 767             (source->stream_count || sink->stream_count))
 768                 return -EBUSY;
 769
 770         mdev = source->graph_obj.mdev;
 771
 772         if (mdev->link_notify) {
 773                 ret = mdev->link_notify(link, flags,
 774                                         MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 775                 if (ret < 0)
 776                         return ret;
 777         }
 778
 779         ret = __media_entity_setup_link_notify(link, flags);
 780
 781         if (mdev->link_notify)
 782                 mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);
 783
 784         return ret;
 785 }
 786
 787 int media_entity_setup_link(struct media_link *link, u32 flags)
 788 {
 789         int ret;
 790
 791         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 792         ret = __media_entity_setup_link(link, flags);
 793         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 794
 795         return ret;
 796 }
 797 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 798
 799 struct media_link *
 800 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 801 {
 802         struct media_link *link;
 803
 804         list_for_each_entry(link, &source->entity->links, list) {
 805                 if (link->source->entity == source->entity &&
 806                     link->source->index == source->index &&
 807                     link->sink->entity == sink->entity &&
 808                     link->sink->index == sink->index)
 809                         return link;
 810         }
 811
 812         return NULL;
 813 }
 814 EXPORT_SYMBOL_GPL(media_entity_find_link);
 815
 816 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 817 {
 818         struct media_link *link;
 819
 820         list_for_each_entry(link, &pad->entity->links, list) {
 821                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 822                         continue;
 823
 824                 if (link->source == pad)
 825                         return link->sink;
 826
 827                 if (link->sink == pad)
 828                         return link->source;
 829         }
 830
 831         return NULL;
 832
 833 }
 834 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 835
 836 static void media_interface_init(struct media_device *mdev,
 837                                  struct media_interface *intf,
 838                                  u32 gobj_type,
 839                                  u32 intf_type, u32 flags)
 840 {
 841         intf->type = intf_type;
 842         intf->flags = flags;
 843         INIT_LIST_HEAD(&intf->links);
 844
 845         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 846 }
 847
 848 /* Functions related to the media interface via device nodes */
 849
 850 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 851                                                 u32 type, u32 flags,
 852                                                 u32 major, u32 minor)
 853 {
 854         struct media_intf_devnode *devnode;
 855
 856         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 857         if (!devnode)
 858                 return NULL;
 859
 860         devnode->major = major;
 861         devnode->minor = minor;
 862
 863         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 864                              type, flags);
 865
 866         return devnode;
 867 }
 868 EXPORT_SYMBOL_GPL(media_devnode_create);
 869
 870 void media_devnode_remove(struct media_intf_devnode *devnode)
 871 {
 872         media_remove_intf_links(&devnode->intf);
 873         media_gobj_destroy(&devnode->intf.graph_obj);
 874         kfree(devnode);
 875 }
 876 EXPORT_SYMBOL_GPL(media_devnode_remove);
 877
 878 struct media_link *media_create_intf_link(struct media_entity *entity,
 879                                             struct media_interface *intf,
 880                                             u32 flags)
 881 {
 882         struct media_link *link;
 883
 884         link = media_add_link(&intf->links);
 885         if (link == NULL)
 886                 return NULL;
 887
 888         link->intf = intf;
 889         link->entity = entity;
 890         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 891
 892         /* Initialize graph object embedded at the new link */
 893         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 894                         &link->graph_obj);
 895
 896         return link;
 897 }
 898 EXPORT_SYMBOL_GPL(media_create_intf_link);
 899
 900 void __media_remove_intf_link(struct media_link *link)
 901 {
 902         list_del(&link->list);
 903         media_gobj_destroy(&link->graph_obj);
 904         kfree(link);
 905 }
 906 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 907
 908 void media_remove_intf_link(struct media_link *link)
 909 {
 910         struct media_device *mdev = link->graph_obj.mdev;
 911
 912         /* Do nothing if the intf is not registered. */
 913         if (mdev == NULL)
 914                 return;
 915
 916         spin_lock(&mdev->lock);
 917         __media_remove_intf_link(link);
 918         spin_unlock(&mdev->lock);
 919 }
 920 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 921
 922 void __media_remove_intf_links(struct media_interface *intf)
 923 {
 924         struct media_link *link, *tmp;
 925
 926         list_for_each_entry_safe(link, tmp, &intf->links, list)
 927                 __media_remove_intf_link(link);
 928
 929 }
 930 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 931
 932 void media_remove_intf_links(struct media_interface *intf)
 933 {
 934         struct media_device *mdev = intf->graph_obj.mdev;
 935
 936         /* Do nothing if the intf is not registered. */
 937         if (mdev == NULL)
 938                 return;
 939
 940         spin_lock(&mdev->lock);
 941         __media_remove_intf_links(intf);
 942         spin_unlock(&mdev->lock);
 943 }
 944 EXPORT_SYMBOL_GPL(media_remove_intf_links);