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         default:
  68                 return "unknown-intf";
  69         }
  70 };
  71
  72 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  73                                           int idx_max)
  74 {
  75         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  76         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  77                                  GFP_KERNEL);
  78         if (!ent_enum->bmap)
  79                 return -ENOMEM;
  80
  81         bitmap_zero(ent_enum->bmap, idx_max);
  82         ent_enum->idx_max = idx_max;
  83
  84         return 0;
  85 }
  86 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
  87
  88 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
  89 {
  90         kfree(ent_enum->bmap);
  91 }
  92 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
  93
  94 /**
  95  *  dev_dbg_obj - Prints in debug mode a change on some object
  96  *
  97  * @event_name: Name of the event to report. Could be __func__
  98  * @gobj:       Pointer to the object
  99  *
 100  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 101  * won't produce any code.
 102  */
 103 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 104 {
 105 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 106         switch (media_type(gobj)) {
 107         case MEDIA_GRAPH_ENTITY:
 108                 dev_dbg(gobj->mdev->dev,
 109                         "%s id %u: entity '%s'\n",
 110                         event_name, media_id(gobj),
 111                         gobj_to_entity(gobj)->name);
 112                 break;
 113         case MEDIA_GRAPH_LINK:
 114         {
 115                 struct media_link *link = gobj_to_link(gobj);
 116
 117                 dev_dbg(gobj->mdev->dev,
 118                         "%s id %u: %s link id %u ==> id %u\n",
 119                         event_name, media_id(gobj),
 120                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 121                                 "data" : "interface",
 122                         media_id(link->gobj0),
 123                         media_id(link->gobj1));
 124                 break;
 125         }
 126         case MEDIA_GRAPH_PAD:
 127         {
 128                 struct media_pad *pad = gobj_to_pad(gobj);
 129
 130                 dev_dbg(gobj->mdev->dev,
 131                         "%s id %u: %s%spad '%s':%d\n",
 132                         event_name, media_id(gobj),
 133                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 134                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 135                         pad->entity->name, pad->index);
 136                 break;
 137         }
 138         case MEDIA_GRAPH_INTF_DEVNODE:
 139         {
 140                 struct media_interface *intf = gobj_to_intf(gobj);
 141                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 142
 143                 dev_dbg(gobj->mdev->dev,
 144                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 145                         event_name, media_id(gobj),
 146                         intf_type(intf),
 147                         devnode->major, devnode->minor);
 148                 break;
 149         }
 150         }
 151 #endif
 152 }
 153
 154 void media_gobj_create(struct media_device *mdev,
 155                            enum media_gobj_type type,
 156                            struct media_gobj *gobj)
 157 {
 158         BUG_ON(!mdev);
 159
 160         gobj->mdev = mdev;
 161
 162         /* Create a per-type unique object ID */
 163         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 164
 165         switch (type) {
 166         case MEDIA_GRAPH_ENTITY:
 167                 list_add_tail(&gobj->list, &mdev->entities);
 168                 break;
 169         case MEDIA_GRAPH_PAD:
 170                 list_add_tail(&gobj->list, &mdev->pads);
 171                 break;
 172         case MEDIA_GRAPH_LINK:
 173                 list_add_tail(&gobj->list, &mdev->links);
 174                 break;
 175         case MEDIA_GRAPH_INTF_DEVNODE:
 176                 list_add_tail(&gobj->list, &mdev->interfaces);
 177                 break;
 178         }
 179
 180         mdev->topology_version++;
 181
 182         dev_dbg_obj(__func__, gobj);
 183 }
 184
 185 void media_gobj_destroy(struct media_gobj *gobj)
 186 {
 187         /* Do nothing if the object is not linked. */
 188         if (gobj->mdev == NULL)
 189                 return;
 190
 191         dev_dbg_obj(__func__, gobj);
 192
 193         gobj->mdev->topology_version++;
 194
 195         /* Remove the object from mdev list */
 196         list_del(&gobj->list);
 197
 198         gobj->mdev = NULL;
 199 }
 200
 201 /*
 202  * TODO: Get rid of this.
 203  */
 204 #define MEDIA_ENTITY_MAX_PADS           512
 205
 206 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 207                            struct media_pad *pads)
 208 {
 209         struct media_device *mdev = entity->graph_obj.mdev;
 210         unsigned int i;
 211
 212         if (num_pads >= MEDIA_ENTITY_MAX_PADS)
 213                 return -E2BIG;
 214
 215         entity->num_pads = num_pads;
 216         entity->pads = pads;
 217
 218         if (mdev)
 219                 mutex_lock(&mdev->graph_mutex);
 220
 221         for (i = 0; i < num_pads; i++) {
 222                 pads[i].entity = entity;
 223                 pads[i].index = i;
 224                 if (mdev)
 225                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 226                                         &entity->pads[i].graph_obj);
 227         }
 228
 229         if (mdev)
 230                 mutex_unlock(&mdev->graph_mutex);
 231
 232         return 0;
 233 }
 234 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 235
 236 /* -----------------------------------------------------------------------------
 237  * Graph traversal
 238  */
 239
 240 static struct media_entity *
 241 media_entity_other(struct media_entity *entity, struct media_link *link)
 242 {
 243         if (link->source->entity == entity)
 244                 return link->sink->entity;
 245         else
 246                 return link->source->entity;
 247 }
 248
 249 /* push an entity to traversal stack */
 250 static void stack_push(struct media_graph *graph,
 251                        struct media_entity *entity)
 252 {
 253         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 254                 WARN_ON(1);
 255                 return;
 256         }
 257         graph->top++;
 258         graph->stack[graph->top].link = entity->links.next;
 259         graph->stack[graph->top].entity = entity;
 260 }
 261
 262 static struct media_entity *stack_pop(struct media_graph *graph)
 263 {
 264         struct media_entity *entity;
 265
 266         entity = graph->stack[graph->top].entity;
 267         graph->top--;
 268
 269         return entity;
 270 }
 271
 272 #define link_top(en)    ((en)->stack[(en)->top].link)
 273 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 274
 275 /**
 276  * media_graph_walk_init - Allocate resources for graph walk
 277  * @graph: Media graph structure that will be used to walk the graph
 278  * @mdev: Media device
 279  *
 280  * Reserve resources for graph walk in media device's current
 281  * state. The memory must be released using
 282  * media_graph_walk_free().
 283  *
 284  * Returns error on failure, zero on success.
 285  */
 286 __must_check int media_graph_walk_init(
 287         struct media_graph *graph, struct media_device *mdev)
 288 {
 289         return media_entity_enum_init(&graph->ent_enum, mdev);
 290 }
 291 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 292
 293 /**
 294  * media_graph_walk_cleanup - Release resources related to graph walking
 295  * @graph: Media graph structure that was used to walk the graph
 296  */
 297 void media_graph_walk_cleanup(struct media_graph *graph)
 298 {
 299         media_entity_enum_cleanup(&graph->ent_enum);
 300 }
 301 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 302
 303 void media_graph_walk_start(struct media_graph *graph,
 304                             struct media_entity *entity)
 305 {
 306         media_entity_enum_zero(&graph->ent_enum);
 307         media_entity_enum_set(&graph->ent_enum, entity);
 308
 309         graph->top = 0;
 310         graph->stack[graph->top].entity = NULL;
 311         stack_push(graph, entity);
 312         dev_dbg(entity->graph_obj.mdev->dev,
 313                 "begin graph walk at '%s'\n", entity->name);
 314 }
 315 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 316
 317 static void media_graph_walk_iter(struct media_graph *graph)
 318 {
 319         struct media_entity *entity = stack_top(graph);
 320         struct media_link *link;
 321         struct media_entity *next;
 322
 323         link = list_entry(link_top(graph), typeof(*link), list);
 324
 325         /* The link is not enabled so we do not follow. */
 326         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 327                 link_top(graph) = link_top(graph)->next;
 328                 dev_dbg(entity->graph_obj.mdev->dev,
 329                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 330                         link->source->entity->name, link->source->index,
 331                         link->sink->entity->name, link->sink->index);
 332                 return;
 333         }
 334
 335         /* Get the entity in the other end of the link . */
 336         next = media_entity_other(entity, link);
 337
 338         /* Has the entity already been visited? */
 339         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 340                 link_top(graph) = link_top(graph)->next;
 341                 dev_dbg(entity->graph_obj.mdev->dev,
 342                         "walk: skipping entity '%s' (already seen)\n",
 343                         next->name);
 344                 return;
 345         }
 346
 347         /* Push the new entity to stack and start over. */
 348         link_top(graph) = link_top(graph)->next;
 349         stack_push(graph, next);
 350         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 351                 next->name);
 352 }
 353
 354 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 355 {
 356         struct media_entity *entity;
 357
 358         if (stack_top(graph) == NULL)
 359                 return NULL;
 360
 361         /*
 362          * Depth first search. Push entity to stack and continue from
 363          * top of the stack until no more entities on the level can be
 364          * found.
 365          */
 366         while (link_top(graph) != &stack_top(graph)->links)
 367                 media_graph_walk_iter(graph);
 368
 369         entity = stack_pop(graph);
 370         dev_dbg(entity->graph_obj.mdev->dev,
 371                 "walk: returning entity '%s'\n", entity->name);
 372
 373         return entity;
 374 }
 375 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 376
 377 int media_entity_get_fwnode_pad(struct media_entity *entity,
 378                                 struct fwnode_handle *fwnode,
 379                                 unsigned long direction_flags)
 380 {
 381         struct fwnode_endpoint endpoint;
 382         unsigned int i;
 383         int ret;
 384
 385         if (!entity->ops || !entity->ops->get_fwnode_pad) {
 386                 for (i = 0; i < entity->num_pads; i++) {
 387                         if (entity->pads[i].flags & direction_flags)
 388                                 return i;
 389                 }
 390
 391                 return -ENXIO;
 392         }
 393
 394         ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
 395         if (ret)
 396                 return ret;
 397
 398         ret = entity->ops->get_fwnode_pad(&endpoint);
 399         if (ret < 0)
 400                 return ret;
 401
 402         if (ret >= entity->num_pads)
 403                 return -ENXIO;
 404
 405         if (!(entity->pads[ret].flags & direction_flags))
 406                 return -ENXIO;
 407
 408         return ret;
 409 }
 410 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
 411
 412 /* -----------------------------------------------------------------------------
 413  * Pipeline management
 414  */
 415
 416 __must_check int __media_pipeline_start(struct media_entity *entity,
 417                                         struct media_pipeline *pipe)
 418 {
 419         struct media_device *mdev = entity->graph_obj.mdev;
 420         struct media_graph *graph = &pipe->graph;
 421         struct media_entity *entity_err = entity;
 422         struct media_link *link;
 423         int ret;
 424
 425         if (!pipe->streaming_count++) {
 426                 ret = media_graph_walk_init(&pipe->graph, mdev);
 427                 if (ret)
 428                         goto error_graph_walk_start;
 429         }
 430
 431         media_graph_walk_start(&pipe->graph, entity);
 432
 433         while ((entity = media_graph_walk_next(graph))) {
 434                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 435                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 436
 437                 entity->stream_count++;
 438
 439                 if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
 440                         ret = -EBUSY;
 441                         goto error;
 442                 }
 443
 444                 entity->pipe = pipe;
 445
 446                 /* Already streaming --- no need to check. */
 447                 if (entity->stream_count > 1)
 448                         continue;
 449
 450                 if (!entity->ops || !entity->ops->link_validate)
 451                         continue;
 452
 453                 bitmap_zero(active, entity->num_pads);
 454                 bitmap_fill(has_no_links, entity->num_pads);
 455
 456                 list_for_each_entry(link, &entity->links, list) {
 457                         struct media_pad *pad = link->sink->entity == entity
 458                                                 ? link->sink : link->source;
 459
 460                         /* Mark that a pad is connected by a link. */
 461                         bitmap_clear(has_no_links, pad->index, 1);
 462
 463                         /*
 464                          * Pads that either do not need to connect or
 465                          * are connected through an enabled link are
 466                          * fine.
 467                          */
 468                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 469                             link->flags & MEDIA_LNK_FL_ENABLED)
 470                                 bitmap_set(active, pad->index, 1);
 471
 472                         /*
 473                          * Link validation will only take place for
 474                          * sink ends of the link that are enabled.
 475                          */
 476                         if (link->sink != pad ||
 477                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 478                                 continue;
 479
 480                         ret = entity->ops->link_validate(link);
 481                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 482                                 dev_dbg(entity->graph_obj.mdev->dev,
 483                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 484                                         link->source->entity->name,
 485                                         link->source->index,
 486                                         entity->name, link->sink->index, ret);
 487                                 goto error;
 488                         }
 489                 }
 490
 491                 /* Either no links or validated links are fine. */
 492                 bitmap_or(active, active, has_no_links, entity->num_pads);
 493
 494                 if (!bitmap_full(active, entity->num_pads)) {
 495                         ret = -ENOLINK;
 496                         dev_dbg(entity->graph_obj.mdev->dev,
 497                                 "'%s':%u must be connected by an enabled link\n",
 498                                 entity->name,
 499                                 (unsigned)find_first_zero_bit(
 500                                         active, entity->num_pads));
 501                         goto error;
 502                 }
 503         }
 504
 505         return 0;
 506
 507 error:
 508         /*
 509          * Link validation on graph failed. We revert what we did and
 510          * return the error.
 511          */
 512         media_graph_walk_start(graph, entity_err);
 513
 514         while ((entity_err = media_graph_walk_next(graph))) {
 515                 /* Sanity check for negative stream_count */
 516                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 517                         entity_err->stream_count--;
 518                         if (entity_err->stream_count == 0)
 519                                 entity_err->pipe = NULL;
 520                 }
 521
 522                 /*
 523                  * We haven't increased stream_count further than this
 524                  * so we quit here.
 525                  */
 526                 if (entity_err == entity)
 527                         break;
 528         }
 529
 530 error_graph_walk_start:
 531         if (!--pipe->streaming_count)
 532                 media_graph_walk_cleanup(graph);
 533
 534         return ret;
 535 }
 536 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 537
 538 __must_check int media_pipeline_start(struct media_entity *entity,
 539                                       struct media_pipeline *pipe)
 540 {
 541         struct media_device *mdev = entity->graph_obj.mdev;
 542         int ret;
 543
 544         mutex_lock(&mdev->graph_mutex);
 545         ret = __media_pipeline_start(entity, pipe);
 546         mutex_unlock(&mdev->graph_mutex);
 547         return ret;
 548 }
 549 EXPORT_SYMBOL_GPL(media_pipeline_start);
 550
 551 void __media_pipeline_stop(struct media_entity *entity)
 552 {
 553         struct media_graph *graph = &entity->pipe->graph;
 554         struct media_pipeline *pipe = entity->pipe;
 555
 556         /*
 557          * If the following check fails, the driver has performed an
 558          * unbalanced call to media_pipeline_stop()
 559          */
 560         if (WARN_ON(!pipe))
 561                 return;
 562
 563         media_graph_walk_start(graph, entity);
 564
 565         while ((entity = media_graph_walk_next(graph))) {
 566                 /* Sanity check for negative stream_count */
 567                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 568                         entity->stream_count--;
 569                         if (entity->stream_count == 0)
 570                                 entity->pipe = NULL;
 571                 }
 572         }
 573
 574         if (!--pipe->streaming_count)
 575                 media_graph_walk_cleanup(graph);
 576
 577 }
 578 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 579
 580 void media_pipeline_stop(struct media_entity *entity)
 581 {
 582         struct media_device *mdev = entity->graph_obj.mdev;
 583
 584         mutex_lock(&mdev->graph_mutex);
 585         __media_pipeline_stop(entity);
 586         mutex_unlock(&mdev->graph_mutex);
 587 }
 588 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 589
 590 /* -----------------------------------------------------------------------------
 591  * Module use count
 592  */
 593
 594 struct media_entity *media_entity_get(struct media_entity *entity)
 595 {
 596         if (entity == NULL)
 597                 return NULL;
 598
 599         if (entity->graph_obj.mdev->dev &&
 600             !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
 601                 return NULL;
 602
 603         return entity;
 604 }
 605 EXPORT_SYMBOL_GPL(media_entity_get);
 606
 607 void media_entity_put(struct media_entity *entity)
 608 {
 609         if (entity == NULL)
 610                 return;
 611
 612         if (entity->graph_obj.mdev->dev)
 613                 module_put(entity->graph_obj.mdev->dev->driver->owner);
 614 }
 615 EXPORT_SYMBOL_GPL(media_entity_put);
 616
 617 /* -----------------------------------------------------------------------------
 618  * Links management
 619  */
 620
 621 static struct media_link *media_add_link(struct list_head *head)
 622 {
 623         struct media_link *link;
 624
 625         link = kzalloc(sizeof(*link), GFP_KERNEL);
 626         if (link == NULL)
 627                 return NULL;
 628
 629         list_add_tail(&link->list, head);
 630
 631         return link;
 632 }
 633
 634 static void __media_entity_remove_link(struct media_entity *entity,
 635                                        struct media_link *link)
 636 {
 637         struct media_link *rlink, *tmp;
 638         struct media_entity *remote;
 639
 640         if (link->source->entity == entity)
 641                 remote = link->sink->entity;
 642         else
 643                 remote = link->source->entity;
 644
 645         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 646                 if (rlink != link->reverse)
 647                         continue;
 648
 649                 if (link->source->entity == entity)
 650                         remote->num_backlinks--;
 651
 652                 /* Remove the remote link */
 653                 list_del(&rlink->list);
 654                 media_gobj_destroy(&rlink->graph_obj);
 655                 kfree(rlink);
 656
 657                 if (--remote->num_links == 0)
 658                         break;
 659         }
 660         list_del(&link->list);
 661         media_gobj_destroy(&link->graph_obj);
 662         kfree(link);
 663 }
 664
 665 int
 666 media_create_pad_link(struct media_entity *source, u16 source_pad,
 667                          struct media_entity *sink, u16 sink_pad, u32 flags)
 668 {
 669         struct media_link *link;
 670         struct media_link *backlink;
 671
 672         BUG_ON(source == NULL || sink == NULL);
 673         BUG_ON(source_pad >= source->num_pads);
 674         BUG_ON(sink_pad >= sink->num_pads);
 675
 676         link = media_add_link(&source->links);
 677         if (link == NULL)
 678                 return -ENOMEM;
 679
 680         link->source = &source->pads[source_pad];
 681         link->sink = &sink->pads[sink_pad];
 682         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 683
 684         /* Initialize graph object embedded at the new link */
 685         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 686                         &link->graph_obj);
 687
 688         /* Create the backlink. Backlinks are used to help graph traversal and
 689          * are not reported to userspace.
 690          */
 691         backlink = media_add_link(&sink->links);
 692         if (backlink == NULL) {
 693                 __media_entity_remove_link(source, link);
 694                 return -ENOMEM;
 695         }
 696
 697         backlink->source = &source->pads[source_pad];
 698         backlink->sink = &sink->pads[sink_pad];
 699         backlink->flags = flags;
 700         backlink->is_backlink = true;
 701
 702         /* Initialize graph object embedded at the new link */
 703         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 704                         &backlink->graph_obj);
 705
 706         link->reverse = backlink;
 707         backlink->reverse = link;
 708
 709         sink->num_backlinks++;
 710         sink->num_links++;
 711         source->num_links++;
 712
 713         return 0;
 714 }
 715 EXPORT_SYMBOL_GPL(media_create_pad_link);
 716
 717 int media_create_pad_links(const struct media_device *mdev,
 718                            const u32 source_function,
 719                            struct media_entity *source,
 720                            const u16 source_pad,
 721                            const u32 sink_function,
 722                            struct media_entity *sink,
 723                            const u16 sink_pad,
 724                            u32 flags,
 725                            const bool allow_both_undefined)
 726 {
 727         struct media_entity *entity;
 728         unsigned function;
 729         int ret;
 730
 731         /* Trivial case: 1:1 relation */
 732         if (source && sink)
 733                 return media_create_pad_link(source, source_pad,
 734                                              sink, sink_pad, flags);
 735
 736         /* Worse case scenario: n:n relation */
 737         if (!source && !sink) {
 738                 if (!allow_both_undefined)
 739                         return 0;
 740                 media_device_for_each_entity(source, mdev) {
 741                         if (source->function != source_function)
 742                                 continue;
 743                         media_device_for_each_entity(sink, mdev) {
 744                                 if (sink->function != sink_function)
 745                                         continue;
 746                                 ret = media_create_pad_link(source, source_pad,
 747                                                             sink, sink_pad,
 748                                                             flags);
 749                                 if (ret)
 750                                         return ret;
 751                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 752                                            MEDIA_LNK_FL_IMMUTABLE);
 753                         }
 754                 }
 755                 return 0;
 756         }
 757
 758         /* Handle 1:n and n:1 cases */
 759         if (source)
 760                 function = sink_function;
 761         else
 762                 function = source_function;
 763
 764         media_device_for_each_entity(entity, mdev) {
 765                 if (entity->function != function)
 766                         continue;
 767
 768                 if (source)
 769                         ret = media_create_pad_link(source, source_pad,
 770                                                     entity, sink_pad, flags);
 771                 else
 772                         ret = media_create_pad_link(entity, source_pad,
 773                                                     sink, sink_pad, flags);
 774                 if (ret)
 775                         return ret;
 776                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 777         }
 778         return 0;
 779 }
 780 EXPORT_SYMBOL_GPL(media_create_pad_links);
 781
 782 void __media_entity_remove_links(struct media_entity *entity)
 783 {
 784         struct media_link *link, *tmp;
 785
 786         list_for_each_entry_safe(link, tmp, &entity->links, list)
 787                 __media_entity_remove_link(entity, link);
 788
 789         entity->num_links = 0;
 790         entity->num_backlinks = 0;
 791 }
 792 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 793
 794 void media_entity_remove_links(struct media_entity *entity)
 795 {
 796         struct media_device *mdev = entity->graph_obj.mdev;
 797
 798         /* Do nothing if the entity is not registered. */
 799         if (mdev == NULL)
 800                 return;
 801
 802         mutex_lock(&mdev->graph_mutex);
 803         __media_entity_remove_links(entity);
 804         mutex_unlock(&mdev->graph_mutex);
 805 }
 806 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 807
 808 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 809 {
 810         int ret;
 811
 812         /* Notify both entities. */
 813         ret = media_entity_call(link->source->entity, link_setup,
 814                                 link->source, link->sink, flags);
 815         if (ret < 0 && ret != -ENOIOCTLCMD)
 816                 return ret;
 817
 818         ret = media_entity_call(link->sink->entity, link_setup,
 819                                 link->sink, link->source, flags);
 820         if (ret < 0 && ret != -ENOIOCTLCMD) {
 821                 media_entity_call(link->source->entity, link_setup,
 822                                   link->source, link->sink, link->flags);
 823                 return ret;
 824         }
 825
 826         link->flags = flags;
 827         link->reverse->flags = link->flags;
 828
 829         return 0;
 830 }
 831
 832 int __media_entity_setup_link(struct media_link *link, u32 flags)
 833 {
 834         const u32 mask = MEDIA_LNK_FL_ENABLED;
 835         struct media_device *mdev;
 836         struct media_entity *source, *sink;
 837         int ret = -EBUSY;
 838
 839         if (link == NULL)
 840                 return -EINVAL;
 841
 842         /* The non-modifiable link flags must not be modified. */
 843         if ((link->flags & ~mask) != (flags & ~mask))
 844                 return -EINVAL;
 845
 846         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 847                 return link->flags == flags ? 0 : -EINVAL;
 848
 849         if (link->flags == flags)
 850                 return 0;
 851
 852         source = link->source->entity;
 853         sink = link->sink->entity;
 854
 855         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 856             (source->stream_count || sink->stream_count))
 857                 return -EBUSY;
 858
 859         mdev = source->graph_obj.mdev;
 860
 861         if (mdev->ops && mdev->ops->link_notify) {
 862                 ret = mdev->ops->link_notify(link, flags,
 863                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 864                 if (ret < 0)
 865                         return ret;
 866         }
 867
 868         ret = __media_entity_setup_link_notify(link, flags);
 869
 870         if (mdev->ops && mdev->ops->link_notify)
 871                 mdev->ops->link_notify(link, flags,
 872                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 873
 874         return ret;
 875 }
 876 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 877
 878 int media_entity_setup_link(struct media_link *link, u32 flags)
 879 {
 880         int ret;
 881
 882         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 883         ret = __media_entity_setup_link(link, flags);
 884         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 885
 886         return ret;
 887 }
 888 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 889
 890 struct media_link *
 891 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 892 {
 893         struct media_link *link;
 894
 895         list_for_each_entry(link, &source->entity->links, list) {
 896                 if (link->source->entity == source->entity &&
 897                     link->source->index == source->index &&
 898                     link->sink->entity == sink->entity &&
 899                     link->sink->index == sink->index)
 900                         return link;
 901         }
 902
 903         return NULL;
 904 }
 905 EXPORT_SYMBOL_GPL(media_entity_find_link);
 906
 907 struct media_pad *media_entity_remote_pad(const struct media_pad *pad)
 908 {
 909         struct media_link *link;
 910
 911         list_for_each_entry(link, &pad->entity->links, list) {
 912                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 913                         continue;
 914
 915                 if (link->source == pad)
 916                         return link->sink;
 917
 918                 if (link->sink == pad)
 919                         return link->source;
 920         }
 921
 922         return NULL;
 923
 924 }
 925 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 926
 927 static void media_interface_init(struct media_device *mdev,
 928                                  struct media_interface *intf,
 929                                  u32 gobj_type,
 930                                  u32 intf_type, u32 flags)
 931 {
 932         intf->type = intf_type;
 933         intf->flags = flags;
 934         INIT_LIST_HEAD(&intf->links);
 935
 936         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 937 }
 938
 939 /* Functions related to the media interface via device nodes */
 940
 941 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 942                                                 u32 type, u32 flags,
 943                                                 u32 major, u32 minor)
 944 {
 945         struct media_intf_devnode *devnode;
 946
 947         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 948         if (!devnode)
 949                 return NULL;
 950
 951         devnode->major = major;
 952         devnode->minor = minor;
 953
 954         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 955                              type, flags);
 956
 957         return devnode;
 958 }
 959 EXPORT_SYMBOL_GPL(media_devnode_create);
 960
 961 void media_devnode_remove(struct media_intf_devnode *devnode)
 962 {
 963         media_remove_intf_links(&devnode->intf);
 964         media_gobj_destroy(&devnode->intf.graph_obj);
 965         kfree(devnode);
 966 }
 967 EXPORT_SYMBOL_GPL(media_devnode_remove);
 968
 969 struct media_link *media_create_intf_link(struct media_entity *entity,
 970                                             struct media_interface *intf,
 971                                             u32 flags)
 972 {
 973         struct media_link *link;
 974
 975         link = media_add_link(&intf->links);
 976         if (link == NULL)
 977                 return NULL;
 978
 979         link->intf = intf;
 980         link->entity = entity;
 981         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 982
 983         /* Initialize graph object embedded at the new link */
 984         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 985                         &link->graph_obj);
 986
 987         return link;
 988 }
 989 EXPORT_SYMBOL_GPL(media_create_intf_link);
 990
 991 void __media_remove_intf_link(struct media_link *link)
 992 {
 993         list_del(&link->list);
 994         media_gobj_destroy(&link->graph_obj);
 995         kfree(link);
 996 }
 997 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 998
 999 void media_remove_intf_link(struct media_link *link)
1000 {
1001         struct media_device *mdev = link->graph_obj.mdev;
1002
1003         /* Do nothing if the intf is not registered. */
1004         if (mdev == NULL)
1005                 return;
1006
1007         mutex_lock(&mdev->graph_mutex);
1008         __media_remove_intf_link(link);
1009         mutex_unlock(&mdev->graph_mutex);
1010 }
1011 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1012
1013 void __media_remove_intf_links(struct media_interface *intf)
1014 {
1015         struct media_link *link, *tmp;
1016
1017         list_for_each_entry_safe(link, tmp, &intf->links, list)
1018                 __media_remove_intf_link(link);
1019
1020 }
1021 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1022
1023 void media_remove_intf_links(struct media_interface *intf)
1024 {
1025         struct media_device *mdev = intf->graph_obj.mdev;
1026
1027         /* Do nothing if the intf is not registered. */
1028         if (mdev == NULL)
1029                 return;
1030
1031         mutex_lock(&mdev->graph_mutex);
1032         __media_remove_intf_links(intf);
1033         mutex_unlock(&mdev->graph_mutex);
1034 }
1035 EXPORT_SYMBOL_GPL(media_remove_intf_links);