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/property.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         default:
  67                 return "unknown-intf";
  68         }
  69 };
  70
  71 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
  72                                           int idx_max)
  73 {
  74         idx_max = ALIGN(idx_max, BITS_PER_LONG);
  75         ent_enum->bmap = kcalloc(idx_max / BITS_PER_LONG, sizeof(long),
  76                                  GFP_KERNEL);
  77         if (!ent_enum->bmap)
  78                 return -ENOMEM;
  79
  80         bitmap_zero(ent_enum->bmap, idx_max);
  81         ent_enum->idx_max = idx_max;
  82
  83         return 0;
  84 }
  85 EXPORT_SYMBOL_GPL(__media_entity_enum_init);
  86
  87 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
  88 {
  89         kfree(ent_enum->bmap);
  90 }
  91 EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
  92
  93 /**
  94  *  dev_dbg_obj - Prints in debug mode a change on some object
  95  *
  96  * @event_name: Name of the event to report. Could be __func__
  97  * @gobj:       Pointer to the object
  98  *
  99  * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
 100  * won't produce any code.
 101  */
 102 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 103 {
 104 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
 105         switch (media_type(gobj)) {
 106         case MEDIA_GRAPH_ENTITY:
 107                 dev_dbg(gobj->mdev->dev,
 108                         "%s id %u: entity '%s'\n",
 109                         event_name, media_id(gobj),
 110                         gobj_to_entity(gobj)->name);
 111                 break;
 112         case MEDIA_GRAPH_LINK:
 113         {
 114                 struct media_link *link = gobj_to_link(gobj);
 115
 116                 dev_dbg(gobj->mdev->dev,
 117                         "%s id %u: %s link id %u ==> id %u\n",
 118                         event_name, media_id(gobj),
 119                         media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
 120                                 "data" : "interface",
 121                         media_id(link->gobj0),
 122                         media_id(link->gobj1));
 123                 break;
 124         }
 125         case MEDIA_GRAPH_PAD:
 126         {
 127                 struct media_pad *pad = gobj_to_pad(gobj);
 128
 129                 dev_dbg(gobj->mdev->dev,
 130                         "%s id %u: %s%spad '%s':%d\n",
 131                         event_name, media_id(gobj),
 132                         pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
 133                         pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
 134                         pad->entity->name, pad->index);
 135                 break;
 136         }
 137         case MEDIA_GRAPH_INTF_DEVNODE:
 138         {
 139                 struct media_interface *intf = gobj_to_intf(gobj);
 140                 struct media_intf_devnode *devnode = intf_to_devnode(intf);
 141
 142                 dev_dbg(gobj->mdev->dev,
 143                         "%s id %u: intf_devnode %s - major: %d, minor: %d\n",
 144                         event_name, media_id(gobj),
 145                         intf_type(intf),
 146                         devnode->major, devnode->minor);
 147                 break;
 148         }
 149         }
 150 #endif
 151 }
 152
 153 void media_gobj_create(struct media_device *mdev,
 154                            enum media_gobj_type type,
 155                            struct media_gobj *gobj)
 156 {
 157         BUG_ON(!mdev);
 158
 159         gobj->mdev = mdev;
 160
 161         /* Create a per-type unique object ID */
 162         gobj->id = media_gobj_gen_id(type, ++mdev->id);
 163
 164         switch (type) {
 165         case MEDIA_GRAPH_ENTITY:
 166                 list_add_tail(&gobj->list, &mdev->entities);
 167                 break;
 168         case MEDIA_GRAPH_PAD:
 169                 list_add_tail(&gobj->list, &mdev->pads);
 170                 break;
 171         case MEDIA_GRAPH_LINK:
 172                 list_add_tail(&gobj->list, &mdev->links);
 173                 break;
 174         case MEDIA_GRAPH_INTF_DEVNODE:
 175                 list_add_tail(&gobj->list, &mdev->interfaces);
 176                 break;
 177         }
 178
 179         mdev->topology_version++;
 180
 181         dev_dbg_obj(__func__, gobj);
 182 }
 183
 184 void media_gobj_destroy(struct media_gobj *gobj)
 185 {
 186         /* Do nothing if the object is not linked. */
 187         if (gobj->mdev == NULL)
 188                 return;
 189
 190         dev_dbg_obj(__func__, gobj);
 191
 192         gobj->mdev->topology_version++;
 193
 194         /* Remove the object from mdev list */
 195         list_del(&gobj->list);
 196
 197         gobj->mdev = NULL;
 198 }
 199
 200 /*
 201  * TODO: Get rid of this.
 202  */
 203 #define MEDIA_ENTITY_MAX_PADS           512
 204
 205 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 206                            struct media_pad *pads)
 207 {
 208         struct media_device *mdev = entity->graph_obj.mdev;
 209         unsigned int i;
 210
 211         if (num_pads >= MEDIA_ENTITY_MAX_PADS)
 212                 return -E2BIG;
 213
 214         entity->num_pads = num_pads;
 215         entity->pads = pads;
 216
 217         if (mdev)
 218                 mutex_lock(&mdev->graph_mutex);
 219
 220         for (i = 0; i < num_pads; i++) {
 221                 pads[i].entity = entity;
 222                 pads[i].index = i;
 223                 if (mdev)
 224                         media_gobj_create(mdev, MEDIA_GRAPH_PAD,
 225                                         &entity->pads[i].graph_obj);
 226         }
 227
 228         if (mdev)
 229                 mutex_unlock(&mdev->graph_mutex);
 230
 231         return 0;
 232 }
 233 EXPORT_SYMBOL_GPL(media_entity_pads_init);
 234
 235 /* -----------------------------------------------------------------------------
 236  * Graph traversal
 237  */
 238
 239 static struct media_entity *
 240 media_entity_other(struct media_entity *entity, struct media_link *link)
 241 {
 242         if (link->source->entity == entity)
 243                 return link->sink->entity;
 244         else
 245                 return link->source->entity;
 246 }
 247
 248 /* push an entity to traversal stack */
 249 static void stack_push(struct media_graph *graph,
 250                        struct media_entity *entity)
 251 {
 252         if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
 253                 WARN_ON(1);
 254                 return;
 255         }
 256         graph->top++;
 257         graph->stack[graph->top].link = entity->links.next;
 258         graph->stack[graph->top].entity = entity;
 259 }
 260
 261 static struct media_entity *stack_pop(struct media_graph *graph)
 262 {
 263         struct media_entity *entity;
 264
 265         entity = graph->stack[graph->top].entity;
 266         graph->top--;
 267
 268         return entity;
 269 }
 270
 271 #define link_top(en)    ((en)->stack[(en)->top].link)
 272 #define stack_top(en)   ((en)->stack[(en)->top].entity)
 273
 274 /**
 275  * media_graph_walk_init - Allocate resources for graph walk
 276  * @graph: Media graph structure that will be used to walk the graph
 277  * @mdev: Media device
 278  *
 279  * Reserve resources for graph walk in media device's current
 280  * state. The memory must be released using
 281  * media_graph_walk_free().
 282  *
 283  * Returns error on failure, zero on success.
 284  */
 285 __must_check int media_graph_walk_init(
 286         struct media_graph *graph, struct media_device *mdev)
 287 {
 288         return media_entity_enum_init(&graph->ent_enum, mdev);
 289 }
 290 EXPORT_SYMBOL_GPL(media_graph_walk_init);
 291
 292 /**
 293  * media_graph_walk_cleanup - Release resources related to graph walking
 294  * @graph: Media graph structure that was used to walk the graph
 295  */
 296 void media_graph_walk_cleanup(struct media_graph *graph)
 297 {
 298         media_entity_enum_cleanup(&graph->ent_enum);
 299 }
 300 EXPORT_SYMBOL_GPL(media_graph_walk_cleanup);
 301
 302 void media_graph_walk_start(struct media_graph *graph,
 303                             struct media_entity *entity)
 304 {
 305         media_entity_enum_zero(&graph->ent_enum);
 306         media_entity_enum_set(&graph->ent_enum, entity);
 307
 308         graph->top = 0;
 309         graph->stack[graph->top].entity = NULL;
 310         stack_push(graph, entity);
 311         dev_dbg(entity->graph_obj.mdev->dev,
 312                 "begin graph walk at '%s'\n", entity->name);
 313 }
 314 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 315
 316 static void media_graph_walk_iter(struct media_graph *graph)
 317 {
 318         struct media_entity *entity = stack_top(graph);
 319         struct media_link *link;
 320         struct media_entity *next;
 321
 322         link = list_entry(link_top(graph), typeof(*link), list);
 323
 324         /* The link is not enabled so we do not follow. */
 325         if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 326                 link_top(graph) = link_top(graph)->next;
 327                 dev_dbg(entity->graph_obj.mdev->dev,
 328                         "walk: skipping disabled link '%s':%u -> '%s':%u\n",
 329                         link->source->entity->name, link->source->index,
 330                         link->sink->entity->name, link->sink->index);
 331                 return;
 332         }
 333
 334         /* Get the entity in the other end of the link . */
 335         next = media_entity_other(entity, link);
 336
 337         /* Has the entity already been visited? */
 338         if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 339                 link_top(graph) = link_top(graph)->next;
 340                 dev_dbg(entity->graph_obj.mdev->dev,
 341                         "walk: skipping entity '%s' (already seen)\n",
 342                         next->name);
 343                 return;
 344         }
 345
 346         /* Push the new entity to stack and start over. */
 347         link_top(graph) = link_top(graph)->next;
 348         stack_push(graph, next);
 349         dev_dbg(entity->graph_obj.mdev->dev, "walk: pushing '%s' on stack\n",
 350                 next->name);
 351 }
 352
 353 struct media_entity *media_graph_walk_next(struct media_graph *graph)
 354 {
 355         struct media_entity *entity;
 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         entity = stack_pop(graph);
 369         dev_dbg(entity->graph_obj.mdev->dev,
 370                 "walk: returning entity '%s'\n", entity->name);
 371
 372         return entity;
 373 }
 374 EXPORT_SYMBOL_GPL(media_graph_walk_next);
 375
 376 int media_entity_get_fwnode_pad(struct media_entity *entity,
 377                                 struct fwnode_handle *fwnode,
 378                                 unsigned long direction_flags)
 379 {
 380         struct fwnode_endpoint endpoint;
 381         unsigned int i;
 382         int ret;
 383
 384         if (!entity->ops || !entity->ops->get_fwnode_pad) {
 385                 for (i = 0; i < entity->num_pads; i++) {
 386                         if (entity->pads[i].flags & direction_flags)
 387                                 return i;
 388                 }
 389
 390                 return -ENXIO;
 391         }
 392
 393         ret = fwnode_graph_parse_endpoint(fwnode, &endpoint);
 394         if (ret)
 395                 return ret;
 396
 397         ret = entity->ops->get_fwnode_pad(&endpoint);
 398         if (ret < 0)
 399                 return ret;
 400
 401         if (ret >= entity->num_pads)
 402                 return -ENXIO;
 403
 404         if (!(entity->pads[ret].flags & direction_flags))
 405                 return -ENXIO;
 406
 407         return ret;
 408 }
 409 EXPORT_SYMBOL_GPL(media_entity_get_fwnode_pad);
 410
 411 /* -----------------------------------------------------------------------------
 412  * Pipeline management
 413  */
 414
 415 __must_check int __media_pipeline_start(struct media_entity *entity,
 416                                         struct media_pipeline *pipe)
 417 {
 418         struct media_device *mdev = entity->graph_obj.mdev;
 419         struct media_graph *graph = &pipe->graph;
 420         struct media_entity *entity_err = entity;
 421         struct media_link *link;
 422         int ret;
 423
 424         if (!pipe->streaming_count++) {
 425                 ret = media_graph_walk_init(&pipe->graph, mdev);
 426                 if (ret)
 427                         goto error_graph_walk_start;
 428         }
 429
 430         media_graph_walk_start(&pipe->graph, entity);
 431
 432         while ((entity = media_graph_walk_next(graph))) {
 433                 DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 434                 DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
 435
 436                 entity->stream_count++;
 437
 438                 if (entity->pipe && entity->pipe != pipe) {
 439                         pr_err("Pipe active for %s. Can't start for %s\n",
 440                                 entity->name,
 441                                 entity_err->name);
 442                         ret = -EBUSY;
 443                         goto error;
 444                 }
 445
 446                 entity->pipe = pipe;
 447
 448                 /* Already streaming --- no need to check. */
 449                 if (entity->stream_count > 1)
 450                         continue;
 451
 452                 if (!entity->ops || !entity->ops->link_validate)
 453                         continue;
 454
 455                 bitmap_zero(active, entity->num_pads);
 456                 bitmap_fill(has_no_links, entity->num_pads);
 457
 458                 list_for_each_entry(link, &entity->links, list) {
 459                         struct media_pad *pad = link->sink->entity == entity
 460                                                 ? link->sink : link->source;
 461
 462                         /* Mark that a pad is connected by a link. */
 463                         bitmap_clear(has_no_links, pad->index, 1);
 464
 465                         /*
 466                          * Pads that either do not need to connect or
 467                          * are connected through an enabled link are
 468                          * fine.
 469                          */
 470                         if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
 471                             link->flags & MEDIA_LNK_FL_ENABLED)
 472                                 bitmap_set(active, pad->index, 1);
 473
 474                         /*
 475                          * Link validation will only take place for
 476                          * sink ends of the link that are enabled.
 477                          */
 478                         if (link->sink != pad ||
 479                             !(link->flags & MEDIA_LNK_FL_ENABLED))
 480                                 continue;
 481
 482                         ret = entity->ops->link_validate(link);
 483                         if (ret < 0 && ret != -ENOIOCTLCMD) {
 484                                 dev_dbg(entity->graph_obj.mdev->dev,
 485                                         "link validation failed for '%s':%u -> '%s':%u, error %d\n",
 486                                         link->source->entity->name,
 487                                         link->source->index,
 488                                         entity->name, link->sink->index, ret);
 489                                 goto error;
 490                         }
 491                 }
 492
 493                 /* Either no links or validated links are fine. */
 494                 bitmap_or(active, active, has_no_links, entity->num_pads);
 495
 496                 if (!bitmap_full(active, entity->num_pads)) {
 497                         ret = -ENOLINK;
 498                         dev_dbg(entity->graph_obj.mdev->dev,
 499                                 "'%s':%u must be connected by an enabled link\n",
 500                                 entity->name,
 501                                 (unsigned)find_first_zero_bit(
 502                                         active, entity->num_pads));
 503                         goto error;
 504                 }
 505         }
 506
 507         return 0;
 508
 509 error:
 510         /*
 511          * Link validation on graph failed. We revert what we did and
 512          * return the error.
 513          */
 514         media_graph_walk_start(graph, entity_err);
 515
 516         while ((entity_err = media_graph_walk_next(graph))) {
 517                 /* Sanity check for negative stream_count */
 518                 if (!WARN_ON_ONCE(entity_err->stream_count <= 0)) {
 519                         entity_err->stream_count--;
 520                         if (entity_err->stream_count == 0)
 521                                 entity_err->pipe = NULL;
 522                 }
 523
 524                 /*
 525                  * We haven't increased stream_count further than this
 526                  * so we quit here.
 527                  */
 528                 if (entity_err == entity)
 529                         break;
 530         }
 531
 532 error_graph_walk_start:
 533         if (!--pipe->streaming_count)
 534                 media_graph_walk_cleanup(graph);
 535
 536         return ret;
 537 }
 538 EXPORT_SYMBOL_GPL(__media_pipeline_start);
 539
 540 __must_check int media_pipeline_start(struct media_entity *entity,
 541                                       struct media_pipeline *pipe)
 542 {
 543         struct media_device *mdev = entity->graph_obj.mdev;
 544         int ret;
 545
 546         mutex_lock(&mdev->graph_mutex);
 547         ret = __media_pipeline_start(entity, pipe);
 548         mutex_unlock(&mdev->graph_mutex);
 549         return ret;
 550 }
 551 EXPORT_SYMBOL_GPL(media_pipeline_start);
 552
 553 void __media_pipeline_stop(struct media_entity *entity)
 554 {
 555         struct media_graph *graph = &entity->pipe->graph;
 556         struct media_pipeline *pipe = entity->pipe;
 557
 558         /*
 559          * If the following check fails, the driver has performed an
 560          * unbalanced call to media_pipeline_stop()
 561          */
 562         if (WARN_ON(!pipe))
 563                 return;
 564
 565         media_graph_walk_start(graph, entity);
 566
 567         while ((entity = media_graph_walk_next(graph))) {
 568                 /* Sanity check for negative stream_count */
 569                 if (!WARN_ON_ONCE(entity->stream_count <= 0)) {
 570                         entity->stream_count--;
 571                         if (entity->stream_count == 0)
 572                                 entity->pipe = NULL;
 573                 }
 574         }
 575
 576         if (!--pipe->streaming_count)
 577                 media_graph_walk_cleanup(graph);
 578
 579 }
 580 EXPORT_SYMBOL_GPL(__media_pipeline_stop);
 581
 582 void media_pipeline_stop(struct media_entity *entity)
 583 {
 584         struct media_device *mdev = entity->graph_obj.mdev;
 585
 586         mutex_lock(&mdev->graph_mutex);
 587         __media_pipeline_stop(entity);
 588         mutex_unlock(&mdev->graph_mutex);
 589 }
 590 EXPORT_SYMBOL_GPL(media_pipeline_stop);
 591
 592 /* -----------------------------------------------------------------------------
 593  * Links management
 594  */
 595
 596 static struct media_link *media_add_link(struct list_head *head)
 597 {
 598         struct media_link *link;
 599
 600         link = kzalloc(sizeof(*link), GFP_KERNEL);
 601         if (link == NULL)
 602                 return NULL;
 603
 604         list_add_tail(&link->list, head);
 605
 606         return link;
 607 }
 608
 609 static void __media_entity_remove_link(struct media_entity *entity,
 610                                        struct media_link *link)
 611 {
 612         struct media_link *rlink, *tmp;
 613         struct media_entity *remote;
 614
 615         if (link->source->entity == entity)
 616                 remote = link->sink->entity;
 617         else
 618                 remote = link->source->entity;
 619
 620         list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
 621                 if (rlink != link->reverse)
 622                         continue;
 623
 624                 if (link->source->entity == entity)
 625                         remote->num_backlinks--;
 626
 627                 /* Remove the remote link */
 628                 list_del(&rlink->list);
 629                 media_gobj_destroy(&rlink->graph_obj);
 630                 kfree(rlink);
 631
 632                 if (--remote->num_links == 0)
 633                         break;
 634         }
 635         list_del(&link->list);
 636         media_gobj_destroy(&link->graph_obj);
 637         kfree(link);
 638 }
 639
 640 int media_get_pad_index(struct media_entity *entity, bool is_sink,
 641                         enum media_pad_signal_type sig_type)
 642 {
 643         int i;
 644         bool pad_is_sink;
 645
 646         if (!entity)
 647                 return -EINVAL;
 648
 649         for (i = 0; i < entity->num_pads; i++) {
 650                 if (entity->pads[i].flags == MEDIA_PAD_FL_SINK)
 651                         pad_is_sink = true;
 652                 else if (entity->pads[i].flags == MEDIA_PAD_FL_SOURCE)
 653                         pad_is_sink = false;
 654                 else
 655                         continue;       /* This is an error! */
 656
 657                 if (pad_is_sink != is_sink)
 658                         continue;
 659                 if (entity->pads[i].sig_type == sig_type)
 660                         return i;
 661         }
 662         return -EINVAL;
 663 }
 664 EXPORT_SYMBOL_GPL(media_get_pad_index);
 665
 666 int
 667 media_create_pad_link(struct media_entity *source, u16 source_pad,
 668                          struct media_entity *sink, u16 sink_pad, u32 flags)
 669 {
 670         struct media_link *link;
 671         struct media_link *backlink;
 672
 673         BUG_ON(source == NULL || sink == NULL);
 674         BUG_ON(source_pad >= source->num_pads);
 675         BUG_ON(sink_pad >= sink->num_pads);
 676
 677         link = media_add_link(&source->links);
 678         if (link == NULL)
 679                 return -ENOMEM;
 680
 681         link->source = &source->pads[source_pad];
 682         link->sink = &sink->pads[sink_pad];
 683         link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
 684
 685         /* Initialize graph object embedded at the new link */
 686         media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
 687                         &link->graph_obj);
 688
 689         /* Create the backlink. Backlinks are used to help graph traversal and
 690          * are not reported to userspace.
 691          */
 692         backlink = media_add_link(&sink->links);
 693         if (backlink == NULL) {
 694                 __media_entity_remove_link(source, link);
 695                 return -ENOMEM;
 696         }
 697
 698         backlink->source = &source->pads[source_pad];
 699         backlink->sink = &sink->pads[sink_pad];
 700         backlink->flags = flags;
 701         backlink->is_backlink = true;
 702
 703         /* Initialize graph object embedded at the new link */
 704         media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
 705                         &backlink->graph_obj);
 706
 707         link->reverse = backlink;
 708         backlink->reverse = link;
 709
 710         sink->num_backlinks++;
 711         sink->num_links++;
 712         source->num_links++;
 713
 714         return 0;
 715 }
 716 EXPORT_SYMBOL_GPL(media_create_pad_link);
 717
 718 int media_create_pad_links(const struct media_device *mdev,
 719                            const u32 source_function,
 720                            struct media_entity *source,
 721                            const u16 source_pad,
 722                            const u32 sink_function,
 723                            struct media_entity *sink,
 724                            const u16 sink_pad,
 725                            u32 flags,
 726                            const bool allow_both_undefined)
 727 {
 728         struct media_entity *entity;
 729         unsigned function;
 730         int ret;
 731
 732         /* Trivial case: 1:1 relation */
 733         if (source && sink)
 734                 return media_create_pad_link(source, source_pad,
 735                                              sink, sink_pad, flags);
 736
 737         /* Worse case scenario: n:n relation */
 738         if (!source && !sink) {
 739                 if (!allow_both_undefined)
 740                         return 0;
 741                 media_device_for_each_entity(source, mdev) {
 742                         if (source->function != source_function)
 743                                 continue;
 744                         media_device_for_each_entity(sink, mdev) {
 745                                 if (sink->function != sink_function)
 746                                         continue;
 747                                 ret = media_create_pad_link(source, source_pad,
 748                                                             sink, sink_pad,
 749                                                             flags);
 750                                 if (ret)
 751                                         return ret;
 752                                 flags &= ~(MEDIA_LNK_FL_ENABLED |
 753                                            MEDIA_LNK_FL_IMMUTABLE);
 754                         }
 755                 }
 756                 return 0;
 757         }
 758
 759         /* Handle 1:n and n:1 cases */
 760         if (source)
 761                 function = sink_function;
 762         else
 763                 function = source_function;
 764
 765         media_device_for_each_entity(entity, mdev) {
 766                 if (entity->function != function)
 767                         continue;
 768
 769                 if (source)
 770                         ret = media_create_pad_link(source, source_pad,
 771                                                     entity, sink_pad, flags);
 772                 else
 773                         ret = media_create_pad_link(entity, source_pad,
 774                                                     sink, sink_pad, flags);
 775                 if (ret)
 776                         return ret;
 777                 flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 778         }
 779         return 0;
 780 }
 781 EXPORT_SYMBOL_GPL(media_create_pad_links);
 782
 783 void __media_entity_remove_links(struct media_entity *entity)
 784 {
 785         struct media_link *link, *tmp;
 786
 787         list_for_each_entry_safe(link, tmp, &entity->links, list)
 788                 __media_entity_remove_link(entity, link);
 789
 790         entity->num_links = 0;
 791         entity->num_backlinks = 0;
 792 }
 793 EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 794
 795 void media_entity_remove_links(struct media_entity *entity)
 796 {
 797         struct media_device *mdev = entity->graph_obj.mdev;
 798
 799         /* Do nothing if the entity is not registered. */
 800         if (mdev == NULL)
 801                 return;
 802
 803         mutex_lock(&mdev->graph_mutex);
 804         __media_entity_remove_links(entity);
 805         mutex_unlock(&mdev->graph_mutex);
 806 }
 807 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 808
 809 static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
 810 {
 811         int ret;
 812
 813         /* Notify both entities. */
 814         ret = media_entity_call(link->source->entity, link_setup,
 815                                 link->source, link->sink, flags);
 816         if (ret < 0 && ret != -ENOIOCTLCMD)
 817                 return ret;
 818
 819         ret = media_entity_call(link->sink->entity, link_setup,
 820                                 link->sink, link->source, flags);
 821         if (ret < 0 && ret != -ENOIOCTLCMD) {
 822                 media_entity_call(link->source->entity, link_setup,
 823                                   link->source, link->sink, link->flags);
 824                 return ret;
 825         }
 826
 827         link->flags = flags;
 828         link->reverse->flags = link->flags;
 829
 830         return 0;
 831 }
 832
 833 int __media_entity_setup_link(struct media_link *link, u32 flags)
 834 {
 835         const u32 mask = MEDIA_LNK_FL_ENABLED;
 836         struct media_device *mdev;
 837         struct media_entity *source, *sink;
 838         int ret = -EBUSY;
 839
 840         if (link == NULL)
 841                 return -EINVAL;
 842
 843         /* The non-modifiable link flags must not be modified. */
 844         if ((link->flags & ~mask) != (flags & ~mask))
 845                 return -EINVAL;
 846
 847         if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
 848                 return link->flags == flags ? 0 : -EINVAL;
 849
 850         if (link->flags == flags)
 851                 return 0;
 852
 853         source = link->source->entity;
 854         sink = link->sink->entity;
 855
 856         if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
 857             (source->stream_count || sink->stream_count))
 858                 return -EBUSY;
 859
 860         mdev = source->graph_obj.mdev;
 861
 862         if (mdev->ops && mdev->ops->link_notify) {
 863                 ret = mdev->ops->link_notify(link, flags,
 864                                              MEDIA_DEV_NOTIFY_PRE_LINK_CH);
 865                 if (ret < 0)
 866                         return ret;
 867         }
 868
 869         ret = __media_entity_setup_link_notify(link, flags);
 870
 871         if (mdev->ops && mdev->ops->link_notify)
 872                 mdev->ops->link_notify(link, flags,
 873                                        MEDIA_DEV_NOTIFY_POST_LINK_CH);
 874
 875         return ret;
 876 }
 877 EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 878
 879 int media_entity_setup_link(struct media_link *link, u32 flags)
 880 {
 881         int ret;
 882
 883         mutex_lock(&link->graph_obj.mdev->graph_mutex);
 884         ret = __media_entity_setup_link(link, flags);
 885         mutex_unlock(&link->graph_obj.mdev->graph_mutex);
 886
 887         return ret;
 888 }
 889 EXPORT_SYMBOL_GPL(media_entity_setup_link);
 890
 891 struct media_link *
 892 media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 893 {
 894         struct media_link *link;
 895
 896         list_for_each_entry(link, &source->entity->links, list) {
 897                 if (link->source->entity == source->entity &&
 898                     link->source->index == source->index &&
 899                     link->sink->entity == sink->entity &&
 900                     link->sink->index == sink->index)
 901                         return link;
 902         }
 903
 904         return NULL;
 905 }
 906 EXPORT_SYMBOL_GPL(media_entity_find_link);
 907
 908 struct media_pad *media_entity_remote_pad(const struct media_pad *pad)
 909 {
 910         struct media_link *link;
 911
 912         list_for_each_entry(link, &pad->entity->links, list) {
 913                 if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 914                         continue;
 915
 916                 if (link->source == pad)
 917                         return link->sink;
 918
 919                 if (link->sink == pad)
 920                         return link->source;
 921         }
 922
 923         return NULL;
 924
 925 }
 926 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
 927
 928 static void media_interface_init(struct media_device *mdev,
 929                                  struct media_interface *intf,
 930                                  u32 gobj_type,
 931                                  u32 intf_type, u32 flags)
 932 {
 933         intf->type = intf_type;
 934         intf->flags = flags;
 935         INIT_LIST_HEAD(&intf->links);
 936
 937         media_gobj_create(mdev, gobj_type, &intf->graph_obj);
 938 }
 939
 940 /* Functions related to the media interface via device nodes */
 941
 942 struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
 943                                                 u32 type, u32 flags,
 944                                                 u32 major, u32 minor)
 945 {
 946         struct media_intf_devnode *devnode;
 947
 948         devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
 949         if (!devnode)
 950                 return NULL;
 951
 952         devnode->major = major;
 953         devnode->minor = minor;
 954
 955         media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
 956                              type, flags);
 957
 958         return devnode;
 959 }
 960 EXPORT_SYMBOL_GPL(media_devnode_create);
 961
 962 void media_devnode_remove(struct media_intf_devnode *devnode)
 963 {
 964         media_remove_intf_links(&devnode->intf);
 965         media_gobj_destroy(&devnode->intf.graph_obj);
 966         kfree(devnode);
 967 }
 968 EXPORT_SYMBOL_GPL(media_devnode_remove);
 969
 970 struct media_link *media_create_intf_link(struct media_entity *entity,
 971                                             struct media_interface *intf,
 972                                             u32 flags)
 973 {
 974         struct media_link *link;
 975
 976         link = media_add_link(&intf->links);
 977         if (link == NULL)
 978                 return NULL;
 979
 980         link->intf = intf;
 981         link->entity = entity;
 982         link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
 983
 984         /* Initialize graph object embedded at the new link */
 985         media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
 986                         &link->graph_obj);
 987
 988         return link;
 989 }
 990 EXPORT_SYMBOL_GPL(media_create_intf_link);
 991
 992 void __media_remove_intf_link(struct media_link *link)
 993 {
 994         list_del(&link->list);
 995         media_gobj_destroy(&link->graph_obj);
 996         kfree(link);
 997 }
 998 EXPORT_SYMBOL_GPL(__media_remove_intf_link);
 999
1000 void media_remove_intf_link(struct media_link *link)
1001 {
1002         struct media_device *mdev = link->graph_obj.mdev;
1003
1004         /* Do nothing if the intf is not registered. */
1005         if (mdev == NULL)
1006                 return;
1007
1008         mutex_lock(&mdev->graph_mutex);
1009         __media_remove_intf_link(link);
1010         mutex_unlock(&mdev->graph_mutex);
1011 }
1012 EXPORT_SYMBOL_GPL(media_remove_intf_link);
1013
1014 void __media_remove_intf_links(struct media_interface *intf)
1015 {
1016         struct media_link *link, *tmp;
1017
1018         list_for_each_entry_safe(link, tmp, &intf->links, list)
1019                 __media_remove_intf_link(link);
1020
1021 }
1022 EXPORT_SYMBOL_GPL(__media_remove_intf_links);
1023
1024 void media_remove_intf_links(struct media_interface *intf)
1025 {
1026         struct media_device *mdev = intf->graph_obj.mdev;
1027
1028         /* Do nothing if the intf is not registered. */
1029         if (mdev == NULL)
1030                 return;
1031
1032         mutex_lock(&mdev->graph_mutex);
1033         __media_remove_intf_links(intf);
1034         mutex_unlock(&mdev->graph_mutex);
1035 }
1036 EXPORT_SYMBOL_GPL(media_remove_intf_links);