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
  19 #include <linux/bitmap.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <media/media-entity.h>
  23 #include <media/media-device.h>
  24
  25 static inline const char *gobj_type(enum media_gobj_type type)
  26 {
  27         switch (type) {
  28         case MEDIA_GRAPH_ENTITY:
  29                 return "entity";
  30         case MEDIA_GRAPH_PAD:
  31                 return "pad";
  32         case MEDIA_GRAPH_LINK:
  33                 return "link";
  34         case MEDIA_GRAPH_INTF_DEVNODE:
  35                 return "intf-devnode";
  36         default:
  37                 return "unknown";
  38         }
  39 }
  40
  41 static inline const char *intf_type(struct media_interface *intf)
  42 {
  43         switch (intf->type) {
  44         case MEDIA_INTF_T_DVB_FE:
  45                 return "dvb-frontend";
  46         case MEDIA_INTF_T_DVB_DEMUX:
  47                 return "dvb-demux";
  48         case MEDIA_INTF_T_DVB_DVR:
  49                 return "dvb-dvr";
  50         case MEDIA_INTF_T_DVB_CA:
  51                 return  "dvb-ca";
  52         case MEDIA_INTF_T_DVB_NET:
  53                 return "dvb-net";
  54         case MEDIA_INTF_T_V4L_VIDEO:
  55                 return "v4l-video";
  56         case MEDIA_INTF_T_V4L_VBI:
  57                 return "v4l-vbi";
  58         case MEDIA_INTF_T_V4L_RADIO:
  59                 return "v4l-radio";
  60         case MEDIA_INTF_T_V4L_SUBDEV:
  61                 return "v4l-subdev";
  62         case MEDIA_INTF_T_V4L_SWRADIO:
  63                 return "v4l-swradio";
  64         case MEDIA_INTF_T_V4L_TOUCH:
  65                 return "v4l-touch";
  66         case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
  67                 return "alsa-pcm-capture";
  68         case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
  69                 return "alsa-pcm-playback";
  70         case MEDIA_INTF_T_ALSA_CONTROL:
  71                 return "alsa-control";
  72         case MEDIA_INTF_T_ALSA_COMPRESS:
  73                 return "alsa-compress";
  74         case MEDIA_INTF_T_ALSA_RAWMIDI:
  75                 return "alsa-rawmidi";
  76         case MEDIA_INTF_T_ALSA_HWDEP:
  77                 return "alsa-hwdep";
  78         case MEDIA_INTF_T_ALSA_SEQUENCER:
  79                 return "alsa-sequencer";
  80         case MEDIA_INTF_T_ALSA_TIMER:
  81                 return "alsa-timer";
  82         default:
  83                 return "unknown-intf";
  84         }
  85 };
  86
  87 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  88                                           int idx_max)
  89 {
  90         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  91         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  92                                  GFP_KERNEL);
  93         if (!ent_enum->bmap)
  94                 return -ENOMEM;
  95
  96         bitmap_zero(ent_enum->bmap, idx_max);
  97         ent_enum->idx_max = idx_max;
  98
  99         return 0;
 100 }
 101 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
 102
 103 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
 104 {
 105         kfree(ent_enum->bmap);
 106 }
 107 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
 108
 109 /**
 110  *  dev_dbg_obj - Prints in debug mode a change on some object
 111  *
 112  * @event_name: Name of the event to report. Could be __func__
 113  * @gobj:       Pointer to the object
 114  *
 115  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 116  * won't produce any code.
 117  */
 118 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 119 {
 120 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 121         switch (media_type(gobj)) {
 122         case MEDIA_GRAPH_ENTITY:
 123                 dev_dbg(gobj->mdev->dev,
 124                         "%s id %u: entity '%s'\n",
 125                         event_name, media_id(gobj),
 126                         gobj_to_entity(gobj)->name);
 127                 break;
 128         case MEDIA_GRAPH_LINK:
 129         {
 130                 struct media_link *link = gobj_to_link(gobj);
 131
 132                 dev_dbg(gobj->mdev->dev,
 133                         "%s id %u: %s link id %u ==> id %u\n",
 134                         event_name, media_id(gobj),
 135                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 136                                 "data" : "interface",
 137                         media_id(link->gobj0),
 138                         media_id(link->gobj1));
 139                 break;
 140         }
 141         case MEDIA_GRAPH_PAD:
 142         {
 143                 struct media_pad *pad = gobj_to_pad(gobj);
 144
 145                 dev_dbg(gobj->mdev->dev,
 146                         "%s id %u: %s%spad '%s':%d\n",
 147                         event_name, media_id(gobj),
 148                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 149                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 150                         pad->entity->name, pad->index);
 151                 break;
 152         }
 153         case MEDIA_GRAPH_INTF_DEVNODE:
 154         {
 155                 struct media_interface *intf = gobj_to_intf(gobj);
 156                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 157
 158                 dev_dbg(gobj->mdev->dev,
 159                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 160                         event_name, media_id(gobj),
 161                         intf_type(intf),
 162                         devnode->major, devnode->minor);
 163                 break;
 164         }
 165         }
 166 #endif
 167 }
 168
 169 void media_gobj_create(struct media_device *mdev,
 170                            enum media_gobj_type type,
 171                            struct media_gobj *gobj)
 172 {
 173         BUG_ON(!mdev);
 174
 175         gobj->mdev = mdev;
 176
 177         /* Create a per-type unique object ID */
 178         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 179
 180         switch (type) {
 181         case MEDIA_GRAPH_ENTITY:
 182                 list_add_tail(&gobj->list, &mdev->entities);
 183                 break;
 184         case MEDIA_GRAPH_PAD:
 185                 list_add_tail(&gobj->list, &mdev->pads);
 186                 break;
 187         case MEDIA_GRAPH_LINK:
 188                 list_add_tail(&gobj->list, &mdev->links);
 189                 break;
 190         case MEDIA_GRAPH_INTF_DEVNODE:
 191                 list_add_tail(&gobj->list, &mdev->interfaces);
 192                 break;
 193         }
 194
 195         mdev->topology_version++;
 196
 197         dev_dbg_obj(__func__, gobj);
 198 }
 199
 200 void media_gobj_destroy(struct media_gobj *gobj)
 201 {
 202         /* Do nothing if the object is not linked. */
 203         if (gobj->mdev == NULL)
 204                 return;
 205
 206         dev_dbg_obj(__func__, gobj);
 207
 208         gobj->mdev->topology_version++;
 209
 210         /* Remove the object from mdev list */
 211         list_del(&gobj->list);
 212
 213         gobj->mdev = NULL;
 214 }
 215
 216 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 217                            struct media_pad *pads)
 218 {
 219         struct media_device *mdev = entity->graph_obj.mdev;
 220         unsigned int i;
 221
 222         entity->num_pads = num_pads;
 223         entity->pads = pads;
 224
 225         if (mdev)
 226                 mutex_lock(&mdev->graph_mutex);
 227
 228         for (i = 0; i < num_pads; i++) {
 229                 pads[i].entity = entity;
 230                 pads[i].index = i;
 231                 if (mdev)
 232                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 233                                         &entity->pads[i].graph_obj);
 234         }
 235
 236         if (mdev)
 237                 mutex_unlock(&mdev->graph_mutex);
 238
 239         return 0;
 240 }
 241 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 242
 243 /* -----------------------------------------------------------------------------
 244  * Graph traversal
 245  */
 246
 247 static struct media_entity *
 248 media_entity_other(struct media_entity *entity, struct media_link *link)
 249 {
 250         if (link->source->entity == entity)
 251                 return link->sink->entity;
 252         else
 253                 return link->source->entity;
 254 }
 255
 256 /* push an entity to traversal stack */
 257 static void stack_push(struct media_graph *graph,
 258                        struct media_entity *entity)
 259 {
 260         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 261                 WARN_ON(1);
 262                 return;
 263         }
 264         graph->top++;
 265         graph->stack[graph->top].link = entity->links.next;
 266         graph->stack[graph->top].entity = entity;
 267 }
 268
 269 static struct media_entity *stack_pop(struct media_graph *graph)
 270 {
 271         struct media_entity *entity;
 272
 273         entity = graph->stack[graph->top].entity;
 274         graph->top--;
 275
 276         return entity;
 277 }
 278
 279 #define link_top(en)    ((en)->stack[(en)->top].link)
 280 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 281
 282 /*
 283  * TODO: Get rid of this.
 284  */
 285 #define MEDIA_ENTITY_MAX_PADS           512
 286
 287 /**
 288  * media_graph_walk_init - Allocate resources for graph walk
 289  * @graph: Media graph structure that will be used to walk the graph
 290  * @mdev: Media device
 291  *
 292  * Reserve resources for graph walk in media device's current
 293  * state. The memory must be released using
 294  * media_graph_walk_free().
 295  *
 296  * Returns error on failure, zero on success.
 297  */
 298 __must_check int media_graph_walk_init(
 299         struct media_graph *graph, struct media_device *mdev)
 300 {
 301         return media_entity_enum_init(&graph->ent_enum, mdev);
 302 }
 303 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 304
 305 /**
 306  * media_graph_walk_cleanup - Release resources related to graph walking
 307  * @graph: Media graph structure that was used to walk the graph
 308  */
 309 void media_graph_walk_cleanup(struct media_graph *graph)
 310 {
 311         media_entity_enum_cleanup(&graph->ent_enum);
 312 }
 313 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 314
 315 void media_graph_walk_start(struct media_graph *graph,
 316                             struct media_entity *entity)
 317 {
 318         media_entity_enum_zero(&graph->ent_enum);
 319         media_entity_enum_set(&graph->ent_enum, entity);
 320
 321         graph->top = 0;
 322         graph->stack[graph->top].entity = NULL;
 323         stack_push(graph, entity);
 324         dev_dbg(entity->graph_obj.mdev->dev,
 325                 "begin graph walk at '%s'\n", entity->name);
 326 }
 327 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 328
 329 static void media_graph_walk_iter(struct media_graph *graph)
 330 {
 331         struct media_entity *entity = stack_top(graph);
 332         struct media_link *link;
 333         struct media_entity *next;
 334
 335         link = list_entry(link_top(graph), typeof(*link), list);
 336
 337         /* The link is not enabled so we do not follow. */
 338         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 339                 link_top(graph) = link_top(graph)->next;
 340                 dev_dbg(entity->graph_obj.mdev->dev,
 341                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 342                         link->source->entity->name, link->source->index,
 343                         link->sink->entity->name, link->sink->index);
 344                 return;
 345         }
 346
 347         /* Get the entity in the other end of the link . */
 348         next = media_entity_other(entity, link);
 349
 350         /* Has the entity already been visited? */
 351         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 352                 link_top(graph) = link_top(graph)->next;
 353                 dev_dbg(entity->graph_obj.mdev->dev,
 354                         "walk: skipping entity '%s' (already seen)\n",
 355                         next->name);
 356                 return;
 357         }
 358
 359         /* Push the new entity to stack and start over. */
 360         link_top(graph) = link_top(graph)->next;
 361         stack_push(graph, next);
 362         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 363                 next->name);
 364 }
 365
 366 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 367 {
 368         struct media_entity *entity;
 369
 370         if (stack_top(graph) == NULL)
 371                 return NULL;
 372
 373         /*
 374          * Depth first search. Push entity to stack and continue from
 375          * top of the stack until no more entities on the level can be
 376          * found.
 377          */
 378         while (link_top(graph) != &stack_top(graph)->links)
 379                 media_graph_walk_iter(graph);
 380
 381         entity = stack_pop(graph);
 382         dev_dbg(entity->graph_obj.mdev->dev,
 383                 "walk: returning entity '%s'\n", entity->name);
 384
 385         return entity;
 386 }
 387 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 388
 389 /* -----------------------------------------------------------------------------
 390  * Pipeline management
 391  */
 392
 393 __must_check int __media_pipeline_start(struct media_entity *entity,
 394                                         struct media_pipeline *pipe)
 395 {
 396         struct media_device *mdev = entity->graph_obj.mdev;
 397         struct media_graph *graph = &pipe->graph;
 398         struct media_entity *entity_err = entity;
 399         struct media_link *link;
 400         int ret;
 401
 402         if (!pipe->streaming_count++) {
 403                 ret = media_graph_walk_init(&pipe->graph, mdev);
 404                 if (ret)
 405                         goto error_graph_walk_start;
 406         }
 407
 408         media_graph_walk_start(&pipe->graph, entity);
 409
 410         while ((entity = media_graph_walk_next(graph))) {
 411                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 412                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 413
 414                 entity->stream_count++;
 415
 416                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 417                         ret = -EBUSY;
 418                         goto error;
 419                 }
 420
 421                 entity->pipe = pipe;
 422
 423                 /* Already streaming --- no need to check. */
 424                 if (entity->stream_count > 1)
 425                         continue;
 426
 427                 if (!entity->ops || !entity->ops->link_validate)
 428                         continue;
 429
 430                 bitmap_zero(active, entity->num_pads);
 431                 bitmap_fill(has_no_links, entity->num_pads);
 432
 433                 list_for_each_entry(link, &entity->links, list) {
 434                         struct media_pad *pad = link->sink->entity == entity
 435                                                 ? link->sink : link->source;
 436
 437                         /* Mark that a pad is connected by a link. */
 438                         bitmap_clear(has_no_links, pad->index, 1);
 439
 440                         /*
 441                          * Pads that either do not need to connect or
 442                          * are connected through an enabled link are
 443                          * fine.
 444                          */
 445                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 446                             link->flags & MEDIA_LNK_FL_ENABLED)
 447                                 bitmap_set(active, pad->index, 1);
 448
 449                         /*
 450                          * Link validation will only take place for
 451                          * sink ends of the link that are enabled.
 452                          */
 453                         if (link->sink != pad ||
 454                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 455                                 continue;
 456
 457                         ret = entity->ops->link_validate(link);
 458                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 459                                 dev_dbg(entity->graph_obj.mdev->dev,
 460                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 461                                         link->source->entity->name,
 462                                         link->source->index,
 463                                         entity->name, link->sink->index, ret);
 464                                 goto error;
 465                         }
 466                 }
 467
 468                 /* Either no links or validated links are fine. */
 469                 bitmap_or(active, active, has_no_links, entity->num_pads);
 470
 471                 if (!bitmap_full(active, entity->num_pads)) {
 472                         ret = -ENOLINK;
 473                         dev_dbg(entity->graph_obj.mdev->dev,
 474                                 "'%s':%u must be connected by an enabled link\n",
 475                                 entity->name,
 476                                 (unsigned)find_first_zero_bit(
 477                                         active, entity->num_pads));
 478                         goto error;
 479                 }
 480         }
 481
 482         return 0;
 483
 484 error:
 485         /*
 486          * Link validation on graph failed. We revert what we did and
 487          * return the error.
 488          */
 489         media_graph_walk_start(graph, entity_err);
 490
 491         while ((entity_err = media_graph_walk_next(graph))) {
 492                 /* Sanity check for negative stream_count */
 493                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 494                         entity_err->stream_count--;
 495                         if (entity_err->stream_count == 0)
 496                                 entity_err->pipe = NULL;
 497                 }
 498
 499                 /*
 500                  * We haven't increased stream_count further than this
 501                  * so we quit here.
 502                  */
 503                 if (entity_err == entity)
 504                         break;
 505         }
 506
 507 error_graph_walk_start:
 508         if (!--pipe->streaming_count)
 509                 media_graph_walk_cleanup(graph);
 510
 511         return ret;
 512 }
 513 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 514
 515 __must_check int media_pipeline_start(struct media_entity *entity,
 516                                       struct media_pipeline *pipe)
 517 {
 518         struct media_device *mdev = entity->graph_obj.mdev;
 519         int ret;
 520
 521         mutex_lock(&mdev->graph_mutex);
 522         ret = __media_pipeline_start(entity, pipe);
 523         mutex_unlock(&mdev->graph_mutex);
 524         return ret;
 525 }
 526 EXPORT_SYMBOL_GPL(media_pipeline_start);
 527
 528 void __media_pipeline_stop(struct media_entity *entity)
 529 {
 530         struct media_graph *graph = &entity->pipe->graph;
 531         struct media_pipeline *pipe = entity->pipe;
 532
 533
 534         WARN_ON(!pipe->streaming_count);
 535         media_graph_walk_start(graph, entity);
 536
 537         while ((entity = media_graph_walk_next(graph))) {
 538                 /* Sanity check for negative stream_count */
 539                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 540                         entity->stream_count--;
 541                         if (entity->stream_count == 0)
 542                                 entity->pipe = NULL;
 543                 }
 544         }
 545
 546         if (!--pipe->streaming_count)
 547                 media_graph_walk_cleanup(graph);
 548
 549 }
 550 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 551
 552 void media_pipeline_stop(struct media_entity *entity)
 553 {
 554         struct media_device *mdev = entity->graph_obj.mdev;
 555
 556         mutex_lock(&mdev->graph_mutex);
 557         __media_pipeline_stop(entity);
 558         mutex_unlock(&mdev->graph_mutex);
 559 }
 560 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 561
 562 /* -----------------------------------------------------------------------------
 563  * Module use count
 564  */
 565
 566 struct media_entity *media_entity_get(struct media_entity *entity)
 567 {
 568         if (entity == NULL)
 569                 return NULL;
 570
 571         if (entity->graph_obj.mdev->dev &&
 572             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 573                 return NULL;
 574
 575         return entity;
 576 }
 577 EXPORT_SYMBOL_GPL(media_entity_get);
 578
 579 void media_entity_put(struct media_entity *entity)
 580 {
 581         if (entity == NULL)
 582                 return;
 583
 584         if (entity->graph_obj.mdev->dev)
 585                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 586 }
 587 EXPORT_SYMBOL_GPL(media_entity_put);
 588
 589 /* -----------------------------------------------------------------------------
 590  * Links management
 591  */
 592
 593 static struct media_link *media_add_link(struct list_head *head)
 594 {
 595         struct media_link *link;
 596
 597         link = kzalloc(sizeof(*link), GFP_KERNEL);
 598         if (link == NULL)
 599                 return NULL;
 600
 601         list_add_tail(&link->list, head);
 602
 603         return link;
 604 }
 605
 606 static void __media_entity_remove_link(struct media_entity *entity,
 607                                        struct media_link *link)
 608 {
 609         struct media_link *rlink, *tmp;
 610         struct media_entity *remote;
 611
 612         if (link->source->entity == entity)
 613                 remote = link->sink->entity;
 614         else
 615                 remote = link->source->entity;
 616
 617         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 618                 if (rlink != link->reverse)
 619                         continue;
 620
 621                 if (link->source->entity == entity)
 622                         remote->num_backlinks--;
 623
 624                 /* Remove the remote link */
 625                 list_del(&rlink->list);
 626                 media_gobj_destroy(&rlink->graph_obj);
 627                 kfree(rlink);
 628
 629                 if (--remote->num_links == 0)
 630                         break;
 631         }
 632         list_del(&link->list);
 633         media_gobj_destroy(&link->graph_obj);
 634         kfree(link);
 635 }
 636
 637 int
 638 media_create_pad_link(struct media_entity *source, u16 source_pad,
 639                          struct media_entity *sink, u16 sink_pad, u32 flags)
 640 {
 641         struct media_link *link;
 642         struct media_link *backlink;
 643
 644         BUG_ON(source == NULL || sink == NULL);
 645         BUG_ON(source_pad >= source->num_pads);
 646         BUG_ON(sink_pad >= sink->num_pads);
 647
 648         link = media_add_link(&source->links);
 649         if (link == NULL)
 650                 return -ENOMEM;
 651
 652         link->source = &source->pads[source_pad];
 653         link->sink = &sink->pads[sink_pad];
 654         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 655
 656         /* Initialize graph object embedded at the new link */
 657         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 658                         &link->graph_obj);
 659
 660         /* Create the backlink. Backlinks are used to help graph traversal and
 661          * are not reported to userspace.
 662          */
 663         backlink = media_add_link(&sink->links);
 664         if (backlink == NULL) {
 665                 __media_entity_remove_link(source, link);
 666                 return -ENOMEM;
 667         }
 668
 669         backlink->source = &source->pads[source_pad];
 670         backlink->sink = &sink->pads[sink_pad];
 671         backlink->flags = flags;
 672         backlink->is_backlink = true;
 673
 674         /* Initialize graph object embedded at the new link */
 675         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 676                         &backlink->graph_obj);
 677
 678         link->reverse = backlink;
 679         backlink->reverse = link;
 680
 681         sink->num_backlinks++;
 682         sink->num_links++;
 683         source->num_links++;
 684
 685         return 0;
 686 }
 687 EXPORT_SYMBOL_GPL(media_create_pad_link);
 688
 689 int media_create_pad_links(const struct media_device *mdev,
 690                            const u32 source_function,
 691                            struct media_entity *source,
 692                            const u16 source_pad,
 693                            const u32 sink_function,
 694                            struct media_entity *sink,
 695                            const u16 sink_pad,
 696                            u32 flags,
 697                            const bool allow_both_undefined)
 698 {
 699         struct media_entity *entity;
 700         unsigned function;
 701         int ret;
 702
 703         /* Trivial case: 1:1 relation */
 704         if (source && sink)
 705                 return media_create_pad_link(source, source_pad,
 706                                              sink, sink_pad, flags);
 707
 708         /* Worse case scenario: n:n relation */
 709         if (!source && !sink) {
 710                 if (!allow_both_undefined)
 711                         return 0;
 712                 media_device_for_each_entity(source, mdev) {
 713                         if (source->function != source_function)
 714                                 continue;
 715                         media_device_for_each_entity(sink, mdev) {
 716                                 if (sink->function != sink_function)
 717                                         continue;
 718                                 ret = media_create_pad_link(source, source_pad,
 719                                                             sink, sink_pad,
 720                                                             flags);
 721                                 if (ret)
 722                                         return ret;
 723                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 724                                            MEDIA_LNK_FL_IMMUTABLE);
 725                         }
 726                 }
 727                 return 0;
 728         }
 729
 730         /* Handle 1:n and n:1 cases */
 731         if (source)
 732                 function = sink_function;
 733         else
 734                 function = source_function;
 735
 736         media_device_for_each_entity(entity, mdev) {
 737                 if (entity->function != function)
 738                         continue;
 739
 740                 if (source)
 741                         ret = media_create_pad_link(source, source_pad,
 742                                                     entity, sink_pad, flags);
 743                 else
 744                         ret = media_create_pad_link(entity, source_pad,
 745                                                     sink, sink_pad, flags);
 746                 if (ret)
 747                         return ret;
 748                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 749         }
 750         return 0;
 751 }
 752 EXPORT_SYMBOL_GPL(media_create_pad_links);
 753
 754 void __media_entity_remove_links(struct media_entity *entity)
 755 {
 756         struct media_link *link, *tmp;
 757
 758         list_for_each_entry_safe(link, tmp, &entity->links, list)
 759                 __media_entity_remove_link(entity, link);
 760
 761         entity->num_links = 0;
 762         entity->num_backlinks = 0;
 763 }
 764 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 765
 766 void media_entity_remove_links(struct media_entity *entity)
 767 {
 768         struct media_device *mdev = entity->graph_obj.mdev;
 769
 770         /* Do nothing if the entity is not registered. */
 771         if (mdev == NULL)
 772                 return;
 773
 774         mutex_lock(&mdev->graph_mutex);
 775         __media_entity_remove_links(entity);
 776         mutex_unlock(&mdev->graph_mutex);
 777 }
 778 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 779
 780 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 781 {
 782         int ret;
 783
 784         /* Notify both entities. */
 785         ret = media_entity_call(link->source->entity, link_setup,
 786                                 link->source, link->sink, flags);
 787         if (ret < 0 && ret != -ENOIOCTLCMD)
 788                 return ret;
 789
 790         ret = media_entity_call(link->sink->entity, link_setup,
 791                                 link->sink, link->source, flags);
 792         if (ret < 0 && ret != -ENOIOCTLCMD) {
 793                 media_entity_call(link->source->entity, link_setup,
 794                                   link->source, link->sink, link->flags);
 795                 return ret;
 796         }
 797
 798         link->flags = flags;
 799         link->reverse->flags = link->flags;
 800
 801         return 0;
 802 }
 803
 804 int __media_entity_setup_link(struct media_link *link, u32 flags)
 805 {
 806         const u32 mask = MEDIA_LNK_FL_ENABLED;
 807         struct media_device *mdev;
 808         struct media_entity *source, *sink;
 809         int ret = -EBUSY;
 810
 811         if (link == NULL)
 812                 return -EINVAL;
 813
 814         /* The non-modifiable link flags must not be modified. */
 815         if ((link->flags & ~mask) != (flags & ~mask))
 816                 return -EINVAL;
 817
 818         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 819                 return link->flags == flags ? 0 : -EINVAL;
 820
 821         if (link->flags == flags)
 822                 return 0;
 823
 824         source = link->source->entity;
 825         sink = link->sink->entity;
 826
 827         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 828             (source->stream_count || sink->stream_count))
 829                 return -EBUSY;
 830
 831         mdev = source->graph_obj.mdev;
 832
 833         if (mdev->ops && mdev->ops->link_notify) {
 834                 ret = mdev->ops->link_notify(link, flags,
 835                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 836                 if (ret < 0)
 837                         return ret;
 838         }
 839
 840         ret = __media_entity_setup_link_notify(link, flags);
 841
 842         if (mdev->ops && mdev->ops->link_notify)
 843                 mdev->ops->link_notify(link, flags,
 844                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 845
 846         return ret;
 847 }
 848 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 849
 850 int media_entity_setup_link(struct media_link *link, u32 flags)
 851 {
 852         int ret;
 853
 854         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 855         ret = __media_entity_setup_link(link, flags);
 856         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 857
 858         return ret;
 859 }
 860 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 861
 862 struct media_link *
 863 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 864 {
 865         struct media_link *link;
 866
 867         list_for_each_entry(link, &source->entity->links, list) {
 868                 if (link->source->entity == source->entity &&
 869                     link->source->index == source->index &&
 870                     link->sink->entity == sink->entity &&
 871                     link->sink->index == sink->index)
 872                         return link;
 873         }
 874
 875         return NULL;
 876 }
 877 EXPORT_SYMBOL_GPL(media_entity_find_link);
 878
 879 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 880 {
 881         struct media_link *link;
 882
 883         list_for_each_entry(link, &pad->entity->links, list) {
 884                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 885                         continue;
 886
 887                 if (link->source == pad)
 888                         return link->sink;
 889
 890                 if (link->sink == pad)
 891                         return link->source;
 892         }
 893
 894         return NULL;
 895
 896 }
 897 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 898
 899 static void media_interface_init(struct media_device *mdev,
 900                                  struct media_interface *intf,
 901                                  u32 gobj_type,
 902                                  u32 intf_type, u32 flags)
 903 {
 904         intf->type = intf_type;
 905         intf->flags = flags;
 906         INIT_LIST_HEAD(&intf->links);
 907
 908         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 909 }
 910
 911 /* Functions related to the media interface via device nodes */
 912
 913 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 914                                                 u32 type, u32 flags,
 915                                                 u32 major, u32 minor)
 916 {
 917         struct media_intf_devnode *devnode;
 918
 919         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 920         if (!devnode)
 921                 return NULL;
 922
 923         devnode->major = major;
 924         devnode->minor = minor;
 925
 926         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 927                              type, flags);
 928
 929         return devnode;
 930 }
 931 EXPORT_SYMBOL_GPL(media_devnode_create);
 932
 933 void media_devnode_remove(struct media_intf_devnode *devnode)
 934 {
 935         media_remove_intf_links(&devnode->intf);
 936         media_gobj_destroy(&devnode->intf.graph_obj);
 937         kfree(devnode);
 938 }
 939 EXPORT_SYMBOL_GPL(media_devnode_remove);
 940
 941 struct media_link *media_create_intf_link(struct media_entity *entity,
 942                                             struct media_interface *intf,
 943                                             u32 flags)
 944 {
 945         struct media_link *link;
 946
 947         link = media_add_link(&intf->links);
 948         if (link == NULL)
 949                 return NULL;
 950
 951         link->intf = intf;
 952         link->entity = entity;
 953         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 954
 955         /* Initialize graph object embedded at the new link */
 956         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 957                         &link->graph_obj);
 958
 959         return link;
 960 }
 961 EXPORT_SYMBOL_GPL(media_create_intf_link);
 962
 963 void __media_remove_intf_link(struct media_link *link)
 964 {
 965         list_del(&link->list);
 966         media_gobj_destroy(&link->graph_obj);
 967         kfree(link);
 968 }
 969 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 970
 971 void media_remove_intf_link(struct media_link *link)
 972 {
 973         struct media_device *mdev = link->graph_obj.mdev;
 974
 975         /* Do nothing if the intf is not registered. */
 976         if (mdev == NULL)
 977                 return;
 978
 979         mutex_lock(&mdev->graph_mutex);
 980         __media_remove_intf_link(link);
 981         mutex_unlock(&mdev->graph_mutex);
 982 }
 983 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 984
 985 void __media_remove_intf_links(struct media_interface *intf)
 986 {
 987         struct media_link *link, *tmp;
 988
 989         list_for_each_entry_safe(link, tmp, &intf->links, list)
 990                 __media_remove_intf_link(link);
 991
 992 }
 993 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 994
 995 void media_remove_intf_links(struct media_interface *intf)
 996 {
 997         struct media_device *mdev = intf->graph_obj.mdev;
 998
 999         /* Do nothing if the intf is not registered. */
1000         if (mdev == NULL)
1001                 return;
1002
1003         mutex_lock(&mdev->graph_mutex);
1004         __media_remove_intf_links(intf);
1005         mutex_unlock(&mdev->graph_mutex);
1006 }
1007 EXPORT_SYMBOL_GPL(media_remove_intf_links);