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/property.h>
  22 #include <linux/slab.h>
  23 #include <media/media-entity.h>
  24 #include <media/media-device.h>
  25
  26 static inline const char *gobj_type(enum media_gobj_type type)
  27 {
  28         switch (type) {
  29         case MEDIA_GRAPH_ENTITY:
  30                 return "entity";
  31         case MEDIA_GRAPH_PAD:
  32                 return "pad";
  33         case MEDIA_GRAPH_LINK:
  34                 return "link";
  35         case MEDIA_GRAPH_INTF_DEVNODE:
  36                 return "intf-devnode";
  37         default:
  38                 return "unknown";
  39         }
  40 }
  41
  42 static inline const char *intf_type(struct media_interface *intf)
  43 {
  44         switch (intf->type) {
  45         case MEDIA_INTF_T_DVB_FE:
  46                 return "dvb-frontend";
  47         case MEDIA_INTF_T_DVB_DEMUX:
  48                 return "dvb-demux";
  49         case MEDIA_INTF_T_DVB_DVR:
  50                 return "dvb-dvr";
  51         case MEDIA_INTF_T_DVB_CA:
  52                 return  "dvb-ca";
  53         case MEDIA_INTF_T_DVB_NET:
  54                 return "dvb-net";
  55         case MEDIA_INTF_T_V4L_VIDEO:
  56                 return "v4l-video";
  57         case MEDIA_INTF_T_V4L_VBI:
  58                 return "v4l-vbi";
  59         case MEDIA_INTF_T_V4L_RADIO:
  60                 return "v4l-radio";
  61         case MEDIA_INTF_T_V4L_SUBDEV:
  62                 return "v4l-subdev";
  63         case MEDIA_INTF_T_V4L_SWRADIO:
  64                 return "v4l-swradio";
  65         case MEDIA_INTF_T_V4L_TOUCH:
  66                 return "v4l-touch";
  67         case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
  68                 return "alsa-pcm-capture";
  69         case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
  70                 return "alsa-pcm-playback";
  71         case MEDIA_INTF_T_ALSA_CONTROL:
  72                 return "alsa-control";
  73         case MEDIA_INTF_T_ALSA_COMPRESS:
  74                 return "alsa-compress";
  75         case MEDIA_INTF_T_ALSA_RAWMIDI:
  76                 return "alsa-rawmidi";
  77         case MEDIA_INTF_T_ALSA_HWDEP:
  78                 return "alsa-hwdep";
  79         case MEDIA_INTF_T_ALSA_SEQUENCER:
  80                 return "alsa-sequencer";
  81         case MEDIA_INTF_T_ALSA_TIMER:
  82                 return "alsa-timer";
  83         default:
  84                 return "unknown-intf";
  85         }
  86 };
  87
  88 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  89                                           int idx_max)
  90 {
  91         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  92         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  93                                  GFP_KERNEL);
  94         if (!ent_enum->bmap)
  95                 return -ENOMEM;
  96
  97         bitmap_zero(ent_enum->bmap, idx_max);
  98         ent_enum->idx_max = idx_max;
  99
 100         return 0;
 101 }
 102 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
 103
 104 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
 105 {
 106         kfree(ent_enum->bmap);
 107 }
 108 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
 109
 110 /**
 111  *  dev_dbg_obj - Prints in debug mode a change on some object
 112  *
 113  * @event_name: Name of the event to report. Could be __func__
 114  * @gobj:       Pointer to the object
 115  *
 116  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 117  * won't produce any code.
 118  */
 119 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 120 {
 121 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 122         switch (media_type(gobj)) {
 123         case MEDIA_GRAPH_ENTITY:
 124                 dev_dbg(gobj->mdev->dev,
 125                         "%s id %u: entity '%s'\n",
 126                         event_name, media_id(gobj),
 127                         gobj_to_entity(gobj)->name);
 128                 break;
 129         case MEDIA_GRAPH_LINK:
 130         {
 131                 struct media_link *link = gobj_to_link(gobj);
 132
 133                 dev_dbg(gobj->mdev->dev,
 134                         "%s id %u: %s link id %u ==> id %u\n",
 135                         event_name, media_id(gobj),
 136                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 137                                 "data" : "interface",
 138                         media_id(link->gobj0),
 139                         media_id(link->gobj1));
 140                 break;
 141         }
 142         case MEDIA_GRAPH_PAD:
 143         {
 144                 struct media_pad *pad = gobj_to_pad(gobj);
 145
 146                 dev_dbg(gobj->mdev->dev,
 147                         "%s id %u: %s%spad '%s':%d\n",
 148                         event_name, media_id(gobj),
 149                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 150                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 151                         pad->entity->name, pad->index);
 152                 break;
 153         }
 154         case MEDIA_GRAPH_INTF_DEVNODE:
 155         {
 156                 struct media_interface *intf = gobj_to_intf(gobj);
 157                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 158
 159                 dev_dbg(gobj->mdev->dev,
 160                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 161                         event_name, media_id(gobj),
 162                         intf_type(intf),
 163                         devnode->major, devnode->minor);
 164                 break;
 165         }
 166         }
 167 #endif
 168 }
 169
 170 void media_gobj_create(struct media_device *mdev,
 171                            enum media_gobj_type type,
 172                            struct media_gobj *gobj)
 173 {
 174         BUG_ON(!mdev);
 175
 176         gobj->mdev = mdev;
 177
 178         /* Create a per-type unique object ID */
 179         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 180
 181         switch (type) {
 182         case MEDIA_GRAPH_ENTITY:
 183                 list_add_tail(&gobj->list, &mdev->entities);
 184                 break;
 185         case MEDIA_GRAPH_PAD:
 186                 list_add_tail(&gobj->list, &mdev->pads);
 187                 break;
 188         case MEDIA_GRAPH_LINK:
 189                 list_add_tail(&gobj->list, &mdev->links);
 190                 break;
 191         case MEDIA_GRAPH_INTF_DEVNODE:
 192                 list_add_tail(&gobj->list, &mdev->interfaces);
 193                 break;
 194         }
 195
 196         mdev->topology_version++;
 197
 198         dev_dbg_obj(__func__, gobj);
 199 }
 200
 201 void media_gobj_destroy(struct media_gobj *gobj)
 202 {
 203         /* Do nothing if the object is not linked. */
 204         if (gobj->mdev == NULL)
 205                 return;
 206
 207         dev_dbg_obj(__func__, gobj);
 208
 209         gobj->mdev->topology_version++;
 210
 211         /* Remove the object from mdev list */
 212         list_del(&gobj->list);
 213
 214         gobj->mdev = NULL;
 215 }
 216
 217 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 218                            struct media_pad *pads)
 219 {
 220         struct media_device *mdev = entity->graph_obj.mdev;
 221         unsigned int i;
 222
 223         entity->num_pads = num_pads;
 224         entity->pads = pads;
 225
 226         if (mdev)
 227                 mutex_lock(&mdev->graph_mutex);
 228
 229         for (i = 0; i < num_pads; i++) {
 230                 pads[i].entity = entity;
 231                 pads[i].index = i;
 232                 if (mdev)
 233                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 234                                         &entity->pads[i].graph_obj);
 235         }
 236
 237         if (mdev)
 238                 mutex_unlock(&mdev->graph_mutex);
 239
 240         return 0;
 241 }
 242 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 243
 244 /* -----------------------------------------------------------------------------
 245  * Graph traversal
 246  */
 247
 248 static struct media_entity *
 249 media_entity_other(struct media_entity *entity, struct media_link *link)
 250 {
 251         if (link->source->entity == entity)
 252                 return link->sink->entity;
 253         else
 254                 return link->source->entity;
 255 }
 256
 257 /* push an entity to traversal stack */
 258 static void stack_push(struct media_graph *graph,
 259                        struct media_entity *entity)
 260 {
 261         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 262                 WARN_ON(1);
 263                 return;
 264         }
 265         graph->top++;
 266         graph->stack[graph->top].link = entity->links.next;
 267         graph->stack[graph->top].entity = entity;
 268 }
 269
 270 static struct media_entity *stack_pop(struct media_graph *graph)
 271 {
 272         struct media_entity *entity;
 273
 274         entity = graph->stack[graph->top].entity;
 275         graph->top--;
 276
 277         return entity;
 278 }
 279
 280 #define link_top(en)    ((en)->stack[(en)->top].link)
 281 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 282
 283 /*
 284  * TODO: Get rid of this.
 285  */
 286 #define MEDIA_ENTITY_MAX_PADS           512
 287
 288 /**
 289  * media_graph_walk_init - Allocate resources for graph walk
 290  * @graph: Media graph structure that will be used to walk the graph
 291  * @mdev: Media device
 292  *
 293  * Reserve resources for graph walk in media device's current
 294  * state. The memory must be released using
 295  * media_graph_walk_free().
 296  *
 297  * Returns error on failure, zero on success.
 298  */
 299 __must_check int media_graph_walk_init(
 300         struct media_graph *graph, struct media_device *mdev)
 301 {
 302         return media_entity_enum_init(&graph->ent_enum, mdev);
 303 }
 304 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 305
 306 /**
 307  * media_graph_walk_cleanup - Release resources related to graph walking
 308  * @graph: Media graph structure that was used to walk the graph
 309  */
 310 void media_graph_walk_cleanup(struct media_graph *graph)
 311 {
 312         media_entity_enum_cleanup(&graph->ent_enum);
 313 }
 314 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 315
 316 void media_graph_walk_start(struct media_graph *graph,
 317                             struct media_entity *entity)
 318 {
 319         media_entity_enum_zero(&graph->ent_enum);
 320         media_entity_enum_set(&graph->ent_enum, entity);
 321
 322         graph->top = 0;
 323         graph->stack[graph->top].entity = NULL;
 324         stack_push(graph, entity);
 325         dev_dbg(entity->graph_obj.mdev->dev,
 326                 "begin graph walk at '%s'\n", entity->name);
 327 }
 328 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 329
 330 static void media_graph_walk_iter(struct media_graph *graph)
 331 {
 332         struct media_entity *entity = stack_top(graph);
 333         struct media_link *link;
 334         struct media_entity *next;
 335
 336         link = list_entry(link_top(graph), typeof(*link), list);
 337
 338         /* The link is not enabled so we do not follow. */
 339         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 340                 link_top(graph) = link_top(graph)->next;
 341                 dev_dbg(entity->graph_obj.mdev->dev,
 342                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 343                         link->source->entity->name, link->source->index,
 344                         link->sink->entity->name, link->sink->index);
 345                 return;
 346         }
 347
 348         /* Get the entity in the other end of the link . */
 349         next = media_entity_other(entity, link);
 350
 351         /* Has the entity already been visited? */
 352         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 353                 link_top(graph) = link_top(graph)->next;
 354                 dev_dbg(entity->graph_obj.mdev->dev,
 355                         "walk: skipping entity '%s' (already seen)\n",
 356                         next->name);
 357                 return;
 358         }
 359
 360         /* Push the new entity to stack and start over. */
 361         link_top(graph) = link_top(graph)->next;
 362         stack_push(graph, next);
 363         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 364                 next->name);
 365 }
 366
 367 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 368 {
 369         struct media_entity *entity;
 370
 371         if (stack_top(graph) == NULL)
 372                 return NULL;
 373
 374         /*
 375          * Depth first search. Push entity to stack and continue from
 376          * top of the stack until no more entities on the level can be
 377          * found.
 378          */
 379         while (link_top(graph) != &stack_top(graph)->links)
 380                 media_graph_walk_iter(graph);
 381
 382         entity = stack_pop(graph);
 383         dev_dbg(entity->graph_obj.mdev->dev,
 384                 "walk: returning entity '%s'\n", entity->name);
 385
 386         return entity;
 387 }
 388 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 389
 390 int media_entity_get_fwnode_pad(struct media_entity *entity,
 391                                 struct fwnode_handle *fwnode,
 392                                 unsigned long direction_flags)
 393 {
 394         struct fwnode_endpoint endpoint;
 395         unsigned int i;
 396         int ret;
 397
 398         if (!entity->ops || !entity->ops->get_fwnode_pad) {
 399                 for (i = 0; i < entity->num_pads; i++) {
 400                         if (entity->pads[i].flags & direction_flags)
 401                                 return i;
 402                 }
 403
 404                 return -ENXIO;
 405         }
 406
 407         ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
 408         if (ret)
 409                 return ret;
 410
 411         ret = entity->ops->get_fwnode_pad(&endpoint);
 412         if (ret < 0)
 413                 return ret;
 414
 415         if (ret >= entity->num_pads)
 416                 return -ENXIO;
 417
 418         if (!(entity->pads[ret].flags & direction_flags))
 419                 return -ENXIO;
 420
 421         return ret;
 422 }
 423 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
 424
 425 /* -----------------------------------------------------------------------------
 426  * Pipeline management
 427  */
 428
 429 __must_check int __media_pipeline_start(struct media_entity *entity,
 430                                         struct media_pipeline *pipe)
 431 {
 432         struct media_device *mdev = entity->graph_obj.mdev;
 433         struct media_graph *graph = &pipe->graph;
 434         struct media_entity *entity_err = entity;
 435         struct media_link *link;
 436         int ret;
 437
 438         if (!pipe->streaming_count++) {
 439                 ret = media_graph_walk_init(&pipe->graph, mdev);
 440                 if (ret)
 441                         goto error_graph_walk_start;
 442         }
 443
 444         media_graph_walk_start(&pipe->graph, entity);
 445
 446         while ((entity = media_graph_walk_next(graph))) {
 447                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 448                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 449
 450                 entity->stream_count++;
 451
 452                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 453                         ret = -EBUSY;
 454                         goto error;
 455                 }
 456
 457                 entity->pipe = pipe;
 458
 459                 /* Already streaming --- no need to check. */
 460                 if (entity->stream_count > 1)
 461                         continue;
 462
 463                 if (!entity->ops || !entity->ops->link_validate)
 464                         continue;
 465
 466                 bitmap_zero(active, entity->num_pads);
 467                 bitmap_fill(has_no_links, entity->num_pads);
 468
 469                 list_for_each_entry(link, &entity->links, list) {
 470                         struct media_pad *pad = link->sink->entity == entity
 471                                                 ? link->sink : link->source;
 472
 473                         /* Mark that a pad is connected by a link. */
 474                         bitmap_clear(has_no_links, pad->index, 1);
 475
 476                         /*
 477                          * Pads that either do not need to connect or
 478                          * are connected through an enabled link are
 479                          * fine.
 480                          */
 481                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 482                             link->flags & MEDIA_LNK_FL_ENABLED)
 483                                 bitmap_set(active, pad->index, 1);
 484
 485                         /*
 486                          * Link validation will only take place for
 487                          * sink ends of the link that are enabled.
 488                          */
 489                         if (link->sink != pad ||
 490                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 491                                 continue;
 492
 493                         ret = entity->ops->link_validate(link);
 494                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 495                                 dev_dbg(entity->graph_obj.mdev->dev,
 496                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 497                                         link->source->entity->name,
 498                                         link->source->index,
 499                                         entity->name, link->sink->index, ret);
 500                                 goto error;
 501                         }
 502                 }
 503
 504                 /* Either no links or validated links are fine. */
 505                 bitmap_or(active, active, has_no_links, entity->num_pads);
 506
 507                 if (!bitmap_full(active, entity->num_pads)) {
 508                         ret = -ENOLINK;
 509                         dev_dbg(entity->graph_obj.mdev->dev,
 510                                 "'%s':%u must be connected by an enabled link\n",
 511                                 entity->name,
 512                                 (unsigned)find_first_zero_bit(
 513                                         active, entity->num_pads));
 514                         goto error;
 515                 }
 516         }
 517
 518         return 0;
 519
 520 error:
 521         /*
 522          * Link validation on graph failed. We revert what we did and
 523          * return the error.
 524          */
 525         media_graph_walk_start(graph, entity_err);
 526
 527         while ((entity_err = media_graph_walk_next(graph))) {
 528                 /* Sanity check for negative stream_count */
 529                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 530                         entity_err->stream_count--;
 531                         if (entity_err->stream_count == 0)
 532                                 entity_err->pipe = NULL;
 533                 }
 534
 535                 /*
 536                  * We haven't increased stream_count further than this
 537                  * so we quit here.
 538                  */
 539                 if (entity_err == entity)
 540                         break;
 541         }
 542
 543 error_graph_walk_start:
 544         if (!--pipe->streaming_count)
 545                 media_graph_walk_cleanup(graph);
 546
 547         return ret;
 548 }
 549 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 550
 551 __must_check int media_pipeline_start(struct media_entity *entity,
 552                                       struct media_pipeline *pipe)
 553 {
 554         struct media_device *mdev = entity->graph_obj.mdev;
 555         int ret;
 556
 557         mutex_lock(&mdev->graph_mutex);
 558         ret = __media_pipeline_start(entity, pipe);
 559         mutex_unlock(&mdev->graph_mutex);
 560         return ret;
 561 }
 562 EXPORT_SYMBOL_GPL(media_pipeline_start);
 563
 564 void __media_pipeline_stop(struct media_entity *entity)
 565 {
 566         struct media_graph *graph = &entity->pipe->graph;
 567         struct media_pipeline *pipe = entity->pipe;
 568
 569         /*
 570          * If the following check fails, the driver has performed an
 571          * unbalanced call to media_pipeline_stop()
 572          */
 573         if (WARN_ON(!pipe))
 574                 return;
 575
 576         media_graph_walk_start(graph, entity);
 577
 578         while ((entity = media_graph_walk_next(graph))) {
 579                 /* Sanity check for negative stream_count */
 580                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 581                         entity->stream_count--;
 582                         if (entity->stream_count == 0)
 583                                 entity->pipe = NULL;
 584                 }
 585         }
 586
 587         if (!--pipe->streaming_count)
 588                 media_graph_walk_cleanup(graph);
 589
 590 }
 591 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 592
 593 void media_pipeline_stop(struct media_entity *entity)
 594 {
 595         struct media_device *mdev = entity->graph_obj.mdev;
 596
 597         mutex_lock(&mdev->graph_mutex);
 598         __media_pipeline_stop(entity);
 599         mutex_unlock(&mdev->graph_mutex);
 600 }
 601 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 602
 603 /* -----------------------------------------------------------------------------
 604  * Module use count
 605  */
 606
 607 struct media_entity *media_entity_get(struct media_entity *entity)
 608 {
 609         if (entity == NULL)
 610                 return NULL;
 611
 612         if (entity->graph_obj.mdev->dev &&
 613             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 614                 return NULL;
 615
 616         return entity;
 617 }
 618 EXPORT_SYMBOL_GPL(media_entity_get);
 619
 620 void media_entity_put(struct media_entity *entity)
 621 {
 622         if (entity == NULL)
 623                 return;
 624
 625         if (entity->graph_obj.mdev->dev)
 626                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 627 }
 628 EXPORT_SYMBOL_GPL(media_entity_put);
 629
 630 /* -----------------------------------------------------------------------------
 631  * Links management
 632  */
 633
 634 static struct media_link *media_add_link(struct list_head *head)
 635 {
 636         struct media_link *link;
 637
 638         link = kzalloc(sizeof(*link), GFP_KERNEL);
 639         if (link == NULL)
 640                 return NULL;
 641
 642         list_add_tail(&link->list, head);
 643
 644         return link;
 645 }
 646
 647 static void __media_entity_remove_link(struct media_entity *entity,
 648                                        struct media_link *link)
 649 {
 650         struct media_link *rlink, *tmp;
 651         struct media_entity *remote;
 652
 653         if (link->source->entity == entity)
 654                 remote = link->sink->entity;
 655         else
 656                 remote = link->source->entity;
 657
 658         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 659                 if (rlink != link->reverse)
 660                         continue;
 661
 662                 if (link->source->entity == entity)
 663                         remote->num_backlinks--;
 664
 665                 /* Remove the remote link */
 666                 list_del(&rlink->list);
 667                 media_gobj_destroy(&rlink->graph_obj);
 668                 kfree(rlink);
 669
 670                 if (--remote->num_links == 0)
 671                         break;
 672         }
 673         list_del(&link->list);
 674         media_gobj_destroy(&link->graph_obj);
 675         kfree(link);
 676 }
 677
 678 int
 679 media_create_pad_link(struct media_entity *source, u16 source_pad,
 680                          struct media_entity *sink, u16 sink_pad, u32 flags)
 681 {
 682         struct media_link *link;
 683         struct media_link *backlink;
 684
 685         BUG_ON(source == NULL || sink == NULL);
 686         BUG_ON(source_pad >= source->num_pads);
 687         BUG_ON(sink_pad >= sink->num_pads);
 688
 689         link = media_add_link(&source->links);
 690         if (link == NULL)
 691                 return -ENOMEM;
 692
 693         link->source = &source->pads[source_pad];
 694         link->sink = &sink->pads[sink_pad];
 695         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 696
 697         /* Initialize graph object embedded at the new link */
 698         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 699                         &link->graph_obj);
 700
 701         /* Create the backlink. Backlinks are used to help graph traversal and
 702          * are not reported to userspace.
 703          */
 704         backlink = media_add_link(&sink->links);
 705         if (backlink == NULL) {
 706                 __media_entity_remove_link(source, link);
 707                 return -ENOMEM;
 708         }
 709
 710         backlink->source = &source->pads[source_pad];
 711         backlink->sink = &sink->pads[sink_pad];
 712         backlink->flags = flags;
 713         backlink->is_backlink = true;
 714
 715         /* Initialize graph object embedded at the new link */
 716         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 717                         &backlink->graph_obj);
 718
 719         link->reverse = backlink;
 720         backlink->reverse = link;
 721
 722         sink->num_backlinks++;
 723         sink->num_links++;
 724         source->num_links++;
 725
 726         return 0;
 727 }
 728 EXPORT_SYMBOL_GPL(media_create_pad_link);
 729
 730 int media_create_pad_links(const struct media_device *mdev,
 731                            const u32 source_function,
 732                            struct media_entity *source,
 733                            const u16 source_pad,
 734                            const u32 sink_function,
 735                            struct media_entity *sink,
 736                            const u16 sink_pad,
 737                            u32 flags,
 738                            const bool allow_both_undefined)
 739 {
 740         struct media_entity *entity;
 741         unsigned function;
 742         int ret;
 743
 744         /* Trivial case: 1:1 relation */
 745         if (source && sink)
 746                 return media_create_pad_link(source, source_pad,
 747                                              sink, sink_pad, flags);
 748
 749         /* Worse case scenario: n:n relation */
 750         if (!source && !sink) {
 751                 if (!allow_both_undefined)
 752                         return 0;
 753                 media_device_for_each_entity(source, mdev) {
 754                         if (source->function != source_function)
 755                                 continue;
 756                         media_device_for_each_entity(sink, mdev) {
 757                                 if (sink->function != sink_function)
 758                                         continue;
 759                                 ret = media_create_pad_link(source, source_pad,
 760                                                             sink, sink_pad,
 761                                                             flags);
 762                                 if (ret)
 763                                         return ret;
 764                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 765                                            MEDIA_LNK_FL_IMMUTABLE);
 766                         }
 767                 }
 768                 return 0;
 769         }
 770
 771         /* Handle 1:n and n:1 cases */
 772         if (source)
 773                 function = sink_function;
 774         else
 775                 function = source_function;
 776
 777         media_device_for_each_entity(entity, mdev) {
 778                 if (entity->function != function)
 779                         continue;
 780
 781                 if (source)
 782                         ret = media_create_pad_link(source, source_pad,
 783                                                     entity, sink_pad, flags);
 784                 else
 785                         ret = media_create_pad_link(entity, source_pad,
 786                                                     sink, sink_pad, flags);
 787                 if (ret)
 788                         return ret;
 789                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 790         }
 791         return 0;
 792 }
 793 EXPORT_SYMBOL_GPL(media_create_pad_links);
 794
 795 void __media_entity_remove_links(struct media_entity *entity)
 796 {
 797         struct media_link *link, *tmp;
 798
 799         list_for_each_entry_safe(link, tmp, &entity->links, list)
 800                 __media_entity_remove_link(entity, link);
 801
 802         entity->num_links = 0;
 803         entity->num_backlinks = 0;
 804 }
 805 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 806
 807 void media_entity_remove_links(struct media_entity *entity)
 808 {
 809         struct media_device *mdev = entity->graph_obj.mdev;
 810
 811         /* Do nothing if the entity is not registered. */
 812         if (mdev == NULL)
 813                 return;
 814
 815         mutex_lock(&mdev->graph_mutex);
 816         __media_entity_remove_links(entity);
 817         mutex_unlock(&mdev->graph_mutex);
 818 }
 819 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 820
 821 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 822 {
 823         int ret;
 824
 825         /* Notify both entities. */
 826         ret = media_entity_call(link->source->entity, link_setup,
 827                                 link->source, link->sink, flags);
 828         if (ret < 0 && ret != -ENOIOCTLCMD)
 829                 return ret;
 830
 831         ret = media_entity_call(link->sink->entity, link_setup,
 832                                 link->sink, link->source, flags);
 833         if (ret < 0 && ret != -ENOIOCTLCMD) {
 834                 media_entity_call(link->source->entity, link_setup,
 835                                   link->source, link->sink, link->flags);
 836                 return ret;
 837         }
 838
 839         link->flags = flags;
 840         link->reverse->flags = link->flags;
 841
 842         return 0;
 843 }
 844
 845 int __media_entity_setup_link(struct media_link *link, u32 flags)
 846 {
 847         const u32 mask = MEDIA_LNK_FL_ENABLED;
 848         struct media_device *mdev;
 849         struct media_entity *source, *sink;
 850         int ret = -EBUSY;
 851
 852         if (link == NULL)
 853                 return -EINVAL;
 854
 855         /* The non-modifiable link flags must not be modified. */
 856         if ((link->flags & ~mask) != (flags & ~mask))
 857                 return -EINVAL;
 858
 859         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 860                 return link->flags == flags ? 0 : -EINVAL;
 861
 862         if (link->flags == flags)
 863                 return 0;
 864
 865         source = link->source->entity;
 866         sink = link->sink->entity;
 867
 868         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 869             (source->stream_count || sink->stream_count))
 870                 return -EBUSY;
 871
 872         mdev = source->graph_obj.mdev;
 873
 874         if (mdev->ops && mdev->ops->link_notify) {
 875                 ret = mdev->ops->link_notify(link, flags,
 876                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 877                 if (ret < 0)
 878                         return ret;
 879         }
 880
 881         ret = __media_entity_setup_link_notify(link, flags);
 882
 883         if (mdev->ops && mdev->ops->link_notify)
 884                 mdev->ops->link_notify(link, flags,
 885                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 886
 887         return ret;
 888 }
 889 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 890
 891 int media_entity_setup_link(struct media_link *link, u32 flags)
 892 {
 893         int ret;
 894
 895         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 896         ret = __media_entity_setup_link(link, flags);
 897         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 898
 899         return ret;
 900 }
 901 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 902
 903 struct media_link *
 904 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 905 {
 906         struct media_link *link;
 907
 908         list_for_each_entry(link, &source->entity->links, list) {
 909                 if (link->source->entity == source->entity &&
 910                     link->source->index == source->index &&
 911                     link->sink->entity == sink->entity &&
 912                     link->sink->index == sink->index)
 913                         return link;
 914         }
 915
 916         return NULL;
 917 }
 918 EXPORT_SYMBOL_GPL(media_entity_find_link);
 919
 920 struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 921 {
 922         struct media_link *link;
 923
 924         list_for_each_entry(link, &pad->entity->links, list) {
 925                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 926                         continue;
 927
 928                 if (link->source == pad)
 929                         return link->sink;
 930
 931                 if (link->sink == pad)
 932                         return link->source;
 933         }
 934
 935         return NULL;
 936
 937 }
 938 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 939
 940 static void media_interface_init(struct media_device *mdev,
 941                                  struct media_interface *intf,
 942                                  u32 gobj_type,
 943                                  u32 intf_type, u32 flags)
 944 {
 945         intf->type = intf_type;
 946         intf->flags = flags;
 947         INIT_LIST_HEAD(&intf->links);
 948
 949         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 950 }
 951
 952 /* Functions related to the media interface via device nodes */
 953
 954 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 955                                                 u32 type, u32 flags,
 956                                                 u32 major, u32 minor)
 957 {
 958         struct media_intf_devnode *devnode;
 959
 960         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 961         if (!devnode)
 962                 return NULL;
 963
 964         devnode->major = major;
 965         devnode->minor = minor;
 966
 967         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 968                              type, flags);
 969
 970         return devnode;
 971 }
 972 EXPORT_SYMBOL_GPL(media_devnode_create);
 973
 974 void media_devnode_remove(struct media_intf_devnode *devnode)
 975 {
 976         media_remove_intf_links(&devnode->intf);
 977         media_gobj_destroy(&devnode->intf.graph_obj);
 978         kfree(devnode);
 979 }
 980 EXPORT_SYMBOL_GPL(media_devnode_remove);
 981
 982 struct media_link *media_create_intf_link(struct media_entity *entity,
 983                                             struct media_interface *intf,
 984                                             u32 flags)
 985 {
 986         struct media_link *link;
 987
 988         link = media_add_link(&intf->links);
 989         if (link == NULL)
 990                 return NULL;
 991
 992         link->intf = intf;
 993         link->entity = entity;
 994         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 995
 996         /* Initialize graph object embedded at the new link */
 997         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 998                         &link->graph_obj);
 999
1000         return link;
1001 }
1002 EXPORT_SYMBOL_GPL(media_create_intf_link);
1003
1004 void __media_remove_intf_link(struct media_link *link)
1005 {
1006         list_del(&link->list);
1007         media_gobj_destroy(&link->graph_obj);
1008         kfree(link);
1009 }
1010 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
1011
1012 void media_remove_intf_link(struct media_link *link)
1013 {
1014         struct media_device *mdev = link->graph_obj.mdev;
1015
1016         /* Do nothing if the intf is not registered. */
1017         if (mdev == NULL)
1018                 return;
1019
1020         mutex_lock(&mdev->graph_mutex);
1021         __media_remove_intf_link(link);
1022         mutex_unlock(&mdev->graph_mutex);
1023 }
1024 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1025
1026 void __media_remove_intf_links(struct media_interface *intf)
1027 {
1028         struct media_link *link, *tmp;
1029
1030         list_for_each_entry_safe(link, tmp, &intf->links, list)
1031                 __media_remove_intf_link(link);
1032
1033 }
1034 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1035
1036 void media_remove_intf_links(struct media_interface *intf)
1037 {
1038         struct media_device *mdev = intf->graph_obj.mdev;
1039
1040         /* Do nothing if the intf is not registered. */
1041         if (mdev == NULL)
1042                 return;
1043
1044         mutex_lock(&mdev->graph_mutex);
1045         __media_remove_intf_links(intf);
1046         mutex_unlock(&mdev->graph_mutex);
1047 }
1048 EXPORT_SYMBOL_GPL(media_remove_intf_links);