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         dev_dbg_obj(__func__, gobj);
 203
 204         /* Do nothing if the object is not linked. */
 205         if (gobj->mdev == NULL)
 206                 return;
 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 }
 325 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 326
 327 static void media_graph_walk_iter(struct media_graph *graph)
 328 {
 329         struct media_entity *entity = stack_top(graph);
 330         struct media_link *link;
 331         struct media_entity *next;
 332
 333         link = list_entry(link_top(graph), typeof(*link), list);
 334
 335         /* The link is not enabled so we do not follow. */
 336         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 337                 link_top(graph) = link_top(graph)->next;
 338                 return;
 339         }
 340
 341         /* Get the entity in the other end of the link . */
 342         next = media_entity_other(entity, link);
 343
 344         /* Has the entity already been visited? */
 345         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 346                 link_top(graph) = link_top(graph)->next;
 347                 return;
 348         }
 349
 350         /* Push the new entity to stack and start over. */
 351         link_top(graph) = link_top(graph)->next;
 352         stack_push(graph, next);
 353 }
 354
 355 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 356 {
 357         if (stack_top(graph) == NULL)
 358                 return NULL;
 359
 360         /*
 361          * Depth first search. Push entity to stack and continue from
 362          * top of the stack until no more entities on the level can be
 363          * found.
 364          */
 365         while (link_top(graph) != &stack_top(graph)->links)
 366                 media_graph_walk_iter(graph);
 367
 368         return stack_pop(graph);
 369 }
 370 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 371
 372 /* -----------------------------------------------------------------------------
 373  * Pipeline management
 374  */
 375
 376 __must_check int __media_pipeline_start(struct media_entity *entity,
 377                                         struct media_pipeline *pipe)
 378 {
 379         struct media_device *mdev = entity->graph_obj.mdev;
 380         struct media_graph *graph = &pipe->graph;
 381         struct media_entity *entity_err = entity;
 382         struct media_link *link;
 383         int ret;
 384
 385         if (!pipe->streaming_count++) {
 386                 ret = media_graph_walk_init(&pipe->graph, mdev);
 387                 if (ret)
 388                         goto error_graph_walk_start;
 389         }
 390
 391         media_graph_walk_start(&pipe->graph, entity);
 392
 393         while ((entity = media_graph_walk_next(graph))) {
 394                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 395                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 396
 397                 entity->stream_count++;
 398
 399                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 400                         ret = -EBUSY;
 401                         goto error;
 402                 }
 403
 404                 entity->pipe = pipe;
 405
 406                 /* Already streaming --- no need to check. */
 407                 if (entity->stream_count > 1)
 408                         continue;
 409
 410                 if (!entity->ops || !entity->ops->link_validate)
 411                         continue;
 412
 413                 bitmap_zero(active, entity->num_pads);
 414                 bitmap_fill(has_no_links, entity->num_pads);
 415
 416                 list_for_each_entry(link, &entity->links, list) {
 417                         struct media_pad *pad = link->sink->entity == entity
 418                                                 ? link->sink : link->source;
 419
 420                         /* Mark that a pad is connected by a link. */
 421                         bitmap_clear(has_no_links, pad->index, 1);
 422
 423                         /*
 424                          * Pads that either do not need to connect or
 425                          * are connected through an enabled link are
 426                          * fine.
 427                          */
 428                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 429                             link->flags & MEDIA_LNK_FL_ENABLED)
 430                                 bitmap_set(active, pad->index, 1);
 431
 432                         /*
 433                          * Link validation will only take place for
 434                          * sink ends of the link that are enabled.
 435                          */
 436                         if (link->sink != pad ||
 437                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 438                                 continue;
 439
 440                         ret = entity->ops->link_validate(link);
 441                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 442                                 dev_dbg(entity->graph_obj.mdev->dev,
 443                                         "link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 444                                         link->source->entity->name,
 445                                         link->source->index,
 446                                         entity->name, link->sink->index, ret);
 447                                 goto error;
 448                         }
 449                 }
 450
 451                 /* Either no links or validated links are fine. */
 452                 bitmap_or(active, active, has_no_links, entity->num_pads);
 453
 454                 if (!bitmap_full(active, entity->num_pads)) {
 455                         ret = -ENOLINK;
 456                         dev_dbg(entity->graph_obj.mdev->dev,
 457                                 "\"%s\":%u must be connected by an enabled link\n",
 458                                 entity->name,
 459                                 (unsigned)find_first_zero_bit(
 460                                         active, entity->num_pads));
 461                         goto error;
 462                 }
 463         }
 464
 465         return 0;
 466
 467 error:
 468         /*
 469          * Link validation on graph failed. We revert what we did and
 470          * return the error.
 471          */
 472         media_graph_walk_start(graph, entity_err);
 473
 474         while ((entity_err = media_graph_walk_next(graph))) {
 475                 /* Sanity check for negative stream_count */
 476                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 477                         entity_err->stream_count--;
 478                         if (entity_err->stream_count == 0)
 479                                 entity_err->pipe = NULL;
 480                 }
 481
 482                 /*
 483                  * We haven't increased stream_count further than this
 484                  * so we quit here.
 485                  */
 486                 if (entity_err == entity)
 487                         break;
 488         }
 489
 490 error_graph_walk_start:
 491         if (!--pipe->streaming_count)
 492                 media_graph_walk_cleanup(graph);
 493
 494         return ret;
 495 }
 496 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 497
 498 __must_check int media_pipeline_start(struct media_entity *entity,
 499                                       struct media_pipeline *pipe)
 500 {
 501         struct media_device *mdev = entity->graph_obj.mdev;
 502         int ret;
 503
 504         mutex_lock(&mdev->graph_mutex);
 505         ret = __media_pipeline_start(entity, pipe);
 506         mutex_unlock(&mdev->graph_mutex);
 507         return ret;
 508 }
 509 EXPORT_SYMBOL_GPL(media_pipeline_start);
 510
 511 void __media_pipeline_stop(struct media_entity *entity)
 512 {
 513         struct media_graph *graph = &entity->pipe->graph;
 514         struct media_pipeline *pipe = entity->pipe;
 515
 516
 517         WARN_ON(!pipe->streaming_count);
 518         media_graph_walk_start(graph, entity);
 519
 520         while ((entity = media_graph_walk_next(graph))) {
 521                 /* Sanity check for negative stream_count */
 522                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 523                         entity->stream_count--;
 524                         if (entity->stream_count == 0)
 525                                 entity->pipe = NULL;
 526                 }
 527         }
 528
 529         if (!--pipe->streaming_count)
 530                 media_graph_walk_cleanup(graph);
 531
 532 }
 533 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 534
 535 void media_pipeline_stop(struct media_entity *entity)
 536 {
 537         struct media_device *mdev = entity->graph_obj.mdev;
 538
 539         mutex_lock(&mdev->graph_mutex);
 540         __media_pipeline_stop(entity);
 541         mutex_unlock(&mdev->graph_mutex);
 542 }
 543 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 544
 545 /* -----------------------------------------------------------------------------
 546  * Module use count
 547  */
 548
 549 struct media_entity *media_entity_get(struct media_entity *entity)
 550 {
 551         if (entity == NULL)
 552                 return NULL;
 553
 554         if (entity->graph_obj.mdev->dev &&
 555             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 556                 return NULL;
 557
 558         return entity;
 559 }
 560 EXPORT_SYMBOL_GPL(media_entity_get);
 561
 562 void media_entity_put(struct media_entity *entity)
 563 {
 564         if (entity == NULL)
 565                 return;
 566
 567         if (entity->graph_obj.mdev->dev)
 568                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 569 }
 570 EXPORT_SYMBOL_GPL(media_entity_put);
 571
 572 /* -----------------------------------------------------------------------------
 573  * Links management
 574  */
 575
 576 static struct media_link *media_add_link(struct list_head *head)
 577 {
 578         struct media_link *link;
 579
 580         link = kzalloc(sizeof(*link), GFP_KERNEL);
 581         if (link == NULL)
 582                 return NULL;
 583
 584         list_add_tail(&link->list, head);
 585
 586         return link;
 587 }
 588
 589 static void __media_entity_remove_link(struct media_entity *entity,
 590                                        struct media_link *link)
 591 {
 592         struct media_link *rlink, *tmp;
 593         struct media_entity *remote;
 594
 595         if (link->source->entity == entity)
 596                 remote = link->sink->entity;
 597         else
 598                 remote = link->source->entity;
 599
 600         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 601                 if (rlink != link->reverse)
 602                         continue;
 603
 604                 if (link->source->entity == entity)
 605                         remote->num_backlinks--;
 606
 607                 /* Remove the remote link */
 608                 list_del(&rlink->list);
 609                 media_gobj_destroy(&rlink->graph_obj);
 610                 kfree(rlink);
 611
 612                 if (--remote->num_links == 0)
 613                         break;
 614         }
 615         list_del(&link->list);
 616         media_gobj_destroy(&link->graph_obj);
 617         kfree(link);
 618 }
 619
 620 int
 621 media_create_pad_link(struct media_entity *source, u16 source_pad,
 622                          struct media_entity *sink, u16 sink_pad, u32 flags)
 623 {
 624         struct media_link *link;
 625         struct media_link *backlink;
 626
 627         BUG_ON(source == NULL || sink == NULL);
 628         BUG_ON(source_pad >= source->num_pads);
 629         BUG_ON(sink_pad >= sink->num_pads);
 630
 631         link = media_add_link(&source->links);
 632         if (link == NULL)
 633                 return -ENOMEM;
 634
 635         link->source = &source->pads[source_pad];
 636         link->sink = &sink->pads[sink_pad];
 637         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 638
 639         /* Initialize graph object embedded at the new link */
 640         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 641                         &link->graph_obj);
 642
 643         /* Create the backlink. Backlinks are used to help graph traversal and
 644          * are not reported to userspace.
 645          */
 646         backlink = media_add_link(&sink->links);
 647         if (backlink == NULL) {
 648                 __media_entity_remove_link(source, link);
 649                 return -ENOMEM;
 650         }
 651
 652         backlink->source = &source->pads[source_pad];
 653         backlink->sink = &sink->pads[sink_pad];
 654         backlink->flags = flags;
 655         backlink->is_backlink = true;
 656
 657         /* Initialize graph object embedded at the new link */
 658         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 659                         &backlink->graph_obj);
 660
 661         link->reverse = backlink;
 662         backlink->reverse = link;
 663
 664         sink->num_backlinks++;
 665         sink->num_links++;
 666         source->num_links++;
 667
 668         return 0;
 669 }
 670 EXPORT_SYMBOL_GPL(media_create_pad_link);
 671
 672 int media_create_pad_links(const struct media_device *mdev,
 673                            const u32 source_function,
 674                            struct media_entity *source,
 675                            const u16 source_pad,
 676                            const u32 sink_function,
 677                            struct media_entity *sink,
 678                            const u16 sink_pad,
 679                            u32 flags,
 680                            const bool allow_both_undefined)
 681 {
 682         struct media_entity *entity;
 683         unsigned function;
 684         int ret;
 685
 686         /* Trivial case: 1:1 relation */
 687         if (source && sink)
 688                 return media_create_pad_link(source, source_pad,
 689                                              sink, sink_pad, flags);
 690
 691         /* Worse case scenario: n:n relation */
 692         if (!source && !sink) {
 693                 if (!allow_both_undefined)
 694                         return 0;
 695                 media_device_for_each_entity(source, mdev) {
 696                         if (source->function != source_function)
 697                                 continue;
 698                         media_device_for_each_entity(sink, mdev) {
 699                                 if (sink->function != sink_function)
 700                                         continue;
 701                                 ret = media_create_pad_link(source, source_pad,
 702                                                             sink, sink_pad,
 703                                                             flags);
 704                                 if (ret)
 705                                         return ret;
 706                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 707                                            MEDIA_LNK_FL_IMMUTABLE);
 708                         }
 709                 }
 710                 return 0;
 711         }
 712
 713         /* Handle 1:n and n:1 cases */
 714         if (source)
 715                 function = sink_function;
 716         else
 717                 function = source_function;
 718
 719         media_device_for_each_entity(entity, mdev) {
 720                 if (entity->function != function)
 721                         continue;
 722
 723                 if (source)
 724                         ret = media_create_pad_link(source, source_pad,
 725                                                     entity, sink_pad, flags);
 726                 else
 727                         ret = media_create_pad_link(entity, source_pad,
 728                                                     sink, sink_pad, flags);
 729                 if (ret)
 730                         return ret;
 731                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 732         }
 733         return 0;
 734 }
 735 EXPORT_SYMBOL_GPL(media_create_pad_links);
 736
 737 void __media_entity_remove_links(struct media_entity *entity)
 738 {
 739         struct media_link *link, *tmp;
 740
 741         list_for_each_entry_safe(link, tmp, &entity->links, list)
 742                 __media_entity_remove_link(entity, link);
 743
 744         entity->num_links = 0;
 745         entity->num_backlinks = 0;
 746 }
 747 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 748
 749 void media_entity_remove_links(struct media_entity *entity)
 750 {
 751         struct media_device *mdev = entity->graph_obj.mdev;
 752
 753         /* Do nothing if the entity is not registered. */
 754         if (mdev == NULL)
 755                 return;
 756
 757         mutex_lock(&mdev->graph_mutex);
 758         __media_entity_remove_links(entity);
 759         mutex_unlock(&mdev->graph_mutex);
 760 }
 761 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 762
 763 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 764 {
 765         int ret;
 766
 767         /* Notify both entities. */
 768         ret = media_entity_call(link->source->entity, link_setup,
 769                                 link->source, link->sink, flags);
 770         if (ret < 0 && ret != -ENOIOCTLCMD)
 771                 return ret;
 772
 773         ret = media_entity_call(link->sink->entity, link_setup,
 774                                 link->sink, link->source, flags);
 775         if (ret < 0 && ret != -ENOIOCTLCMD) {
 776                 media_entity_call(link->source->entity, link_setup,
 777                                   link->source, link->sink, link->flags);
 778                 return ret;
 779         }
 780
 781         link->flags = flags;
 782         link->reverse->flags = link->flags;
 783
 784         return 0;
 785 }
 786
 787 int __media_entity_setup_link(struct media_link *link, u32 flags)
 788 {
 789         const u32 mask = MEDIA_LNK_FL_ENABLED;
 790         struct media_device *mdev;
 791         struct media_entity *source, *sink;
 792         int ret = -EBUSY;
 793
 794         if (link == NULL)
 795                 return -EINVAL;
 796
 797         /* The non-modifiable link flags must not be modified. */
 798         if ((link->flags & ~mask) != (flags & ~mask))
 799                 return -EINVAL;
 800
 801         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 802                 return link->flags == flags ? 0 : -EINVAL;
 803
 804         if (link->flags == flags)
 805                 return 0;
 806
 807         source = link->source->entity;
 808         sink = link->sink->entity;
 809
 810         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 811             (source->stream_count || sink->stream_count))
 812                 return -EBUSY;
 813
 814         mdev = source->graph_obj.mdev;
 815
 816         if (mdev->ops && mdev->ops->link_notify) {
 817                 ret = mdev->ops->link_notify(link, flags,
 818                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 819                 if (ret < 0)
 820                         return ret;
 821         }
 822
 823         ret = __media_entity_setup_link_notify(link, flags);
 824
 825         if (mdev->ops && mdev->ops->link_notify)
 826                 mdev->ops->link_notify(link, flags,
 827                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 828
 829         return ret;
 830 }
 831 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 832
 833 int media_entity_setup_link(struct media_link *link, u32 flags)
 834 {
 835         int ret;
 836
 837         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 838         ret = __media_entity_setup_link(link, flags);
 839         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 840
 841         return ret;
 842 }
 843 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 844
 845 struct media_link *
 846 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 847 {
 848         struct media_link *link;
 849
 850         list_for_each_entry(link, &source->entity->links, list) {
 851                 if (link->source->entity == source->entity &&
 852                     link->source->index == source->index &&
 853                     link->sink->entity == sink->entity &&
 854                     link->sink->index == sink->index)
 855                         return link;
 856         }
 857
 858         return NULL;
 859 }
 860 EXPORT_SYMBOL_GPL(media_entity_find_link);
 861
 862 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 863 {
 864         struct media_link *link;
 865
 866         list_for_each_entry(link, &pad->entity->links, list) {
 867                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 868                         continue;
 869
 870                 if (link->source == pad)
 871                         return link->sink;
 872
 873                 if (link->sink == pad)
 874                         return link->source;
 875         }
 876
 877         return NULL;
 878
 879 }
 880 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 881
 882 static void media_interface_init(struct media_device *mdev,
 883                                  struct media_interface *intf,
 884                                  u32 gobj_type,
 885                                  u32 intf_type, u32 flags)
 886 {
 887         intf->type = intf_type;
 888         intf->flags = flags;
 889         INIT_LIST_HEAD(&intf->links);
 890
 891         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 892 }
 893
 894 /* Functions related to the media interface via device nodes */
 895
 896 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 897                                                 u32 type, u32 flags,
 898                                                 u32 major, u32 minor)
 899 {
 900         struct media_intf_devnode *devnode;
 901
 902         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 903         if (!devnode)
 904                 return NULL;
 905
 906         devnode->major = major;
 907         devnode->minor = minor;
 908
 909         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 910                              type, flags);
 911
 912         return devnode;
 913 }
 914 EXPORT_SYMBOL_GPL(media_devnode_create);
 915
 916 void media_devnode_remove(struct media_intf_devnode *devnode)
 917 {
 918         media_remove_intf_links(&devnode->intf);
 919         media_gobj_destroy(&devnode->intf.graph_obj);
 920         kfree(devnode);
 921 }
 922 EXPORT_SYMBOL_GPL(media_devnode_remove);
 923
 924 struct media_link *media_create_intf_link(struct media_entity *entity,
 925                                             struct media_interface *intf,
 926                                             u32 flags)
 927 {
 928         struct media_link *link;
 929
 930         link = media_add_link(&intf->links);
 931         if (link == NULL)
 932                 return NULL;
 933
 934         link->intf = intf;
 935         link->entity = entity;
 936         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 937
 938         /* Initialize graph object embedded at the new link */
 939         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 940                         &link->graph_obj);
 941
 942         return link;
 943 }
 944 EXPORT_SYMBOL_GPL(media_create_intf_link);
 945
 946 void __media_remove_intf_link(struct media_link *link)
 947 {
 948         list_del(&link->list);
 949         media_gobj_destroy(&link->graph_obj);
 950         kfree(link);
 951 }
 952 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 953
 954 void media_remove_intf_link(struct media_link *link)
 955 {
 956         struct media_device *mdev = link->graph_obj.mdev;
 957
 958         /* Do nothing if the intf is not registered. */
 959         if (mdev == NULL)
 960                 return;
 961
 962         mutex_lock(&mdev->graph_mutex);
 963         __media_remove_intf_link(link);
 964         mutex_unlock(&mdev->graph_mutex);
 965 }
 966 EXPORT_SYMBOL_GPL(media_remove_intf_link);
 967
 968 void __media_remove_intf_links(struct media_interface *intf)
 969 {
 970         struct media_link *link, *tmp;
 971
 972         list_for_each_entry_safe(link, tmp, &intf->links, list)
 973                 __media_remove_intf_link(link);
 974
 975 }
 976 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
 977
 978 void media_remove_intf_links(struct media_interface *intf)
 979 {
 980         struct media_device *mdev = intf->graph_obj.mdev;
 981
 982         /* Do nothing if the intf is not registered. */
 983         if (mdev == NULL)
 984                 return;
 985
 986         mutex_lock(&mdev->graph_mutex);
 987         __media_remove_intf_links(intf);
 988         mutex_unlock(&mdev->graph_mutex);
 989 }
 990 EXPORT_SYMBOL_GPL(media_remove_intf_links);