drivers/media/v4l2-core/v4l2-mc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 /*
   4  * Media Controller ancillary functions
   5  *
   6  * Copyright (c) 2016 Mauro Carvalho Chehab <mchehab@kernel.org>
   7  * Copyright (C) 2016 Shuah Khan <shuahkh@osg.samsung.com>
   8  * Copyright (C) 2006-2010 Nokia Corporation
   9  * Copyright (c) 2016 Intel Corporation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/pci.h>
  14 #include <linux/usb.h>
  15 #include <media/media-device.h>
  16 #include <media/media-entity.h>
  17 #include <media/v4l2-fh.h>
  18 #include <media/v4l2-mc.h>
  19 #include <media/v4l2-subdev.h>
  20 #include <media/videobuf2-core.h>
  21
  22 int v4l2_mc_create_media_graph(struct media_device *mdev)
  23
  24 {
  25         struct media_entity *entity;
  26         struct media_entity *if_vid = NULL, *if_aud = NULL;
  27         struct media_entity *tuner = NULL, *decoder = NULL;
  28         struct media_entity *io_v4l = NULL, *io_vbi = NULL, *io_swradio = NULL;
  29         bool is_webcam = false;
  30         u32 flags;
  31         int ret;
  32
  33         if (!mdev)
  34                 return 0;
  35
  36         media_device_for_each_entity(entity, mdev) {
  37                 switch (entity->function) {
  38                 case MEDIA_ENT_F_IF_VID_DECODER:
  39                         if_vid = entity;
  40                         break;
  41                 case MEDIA_ENT_F_IF_AUD_DECODER:
  42                         if_aud = entity;
  43                         break;
  44                 case MEDIA_ENT_F_TUNER:
  45                         tuner = entity;
  46                         break;
  47                 case MEDIA_ENT_F_ATV_DECODER:
  48                         decoder = entity;
  49                         break;
  50                 case MEDIA_ENT_F_IO_V4L:
  51                         io_v4l = entity;
  52                         break;
  53                 case MEDIA_ENT_F_IO_VBI:
  54                         io_vbi = entity;
  55                         break;
  56                 case MEDIA_ENT_F_IO_SWRADIO:
  57                         io_swradio = entity;
  58                         break;
  59                 case MEDIA_ENT_F_CAM_SENSOR:
  60                         is_webcam = true;
  61                         break;
  62                 }
  63         }
  64
  65         /* It should have at least one I/O entity */
  66         if (!io_v4l && !io_vbi && !io_swradio)
  67                 return -EINVAL;
  68
  69         /*
  70          * Here, webcams are modelled on a very simple way: the sensor is
  71          * connected directly to the I/O entity. All dirty details, like
  72          * scaler and crop HW are hidden. While such mapping is not enough
  73          * for mc-centric hardware, it is enough for v4l2 interface centric
  74          * PC-consumer's hardware.
  75          */
  76         if (is_webcam) {
  77                 if (!io_v4l)
  78                         return -EINVAL;
  79
  80                 media_device_for_each_entity(entity, mdev) {
  81                         if (entity->function != MEDIA_ENT_F_CAM_SENSOR)
  82                                 continue;
  83                         ret = media_create_pad_link(entity, 0,
  84                                                     io_v4l, 0,
  85                                                     MEDIA_LNK_FL_ENABLED);
  86                         if (ret)
  87                                 return ret;
  88                 }
  89                 if (!decoder)
  90                         return 0;
  91         }
  92
  93         /* The device isn't a webcam. So, it should have a decoder */
  94         if (!decoder)
  95                 return -EINVAL;
  96
  97         /* Link the tuner and IF video output pads */
  98         if (tuner) {
  99                 if (if_vid) {
 100                         ret = media_create_pad_link(tuner, TUNER_PAD_OUTPUT,
 101                                                     if_vid,
 102                                                     IF_VID_DEC_PAD_IF_INPUT,
 103                                                     MEDIA_LNK_FL_ENABLED);
 104                         if (ret)
 105                                 return ret;
 106                         ret = media_create_pad_link(if_vid, IF_VID_DEC_PAD_OUT,
 107                                                 decoder, DEMOD_PAD_IF_INPUT,
 108                                                 MEDIA_LNK_FL_ENABLED);
 109                         if (ret)
 110                                 return ret;
 111                 } else {
 112                         ret = media_create_pad_link(tuner, TUNER_PAD_OUTPUT,
 113                                                 decoder, DEMOD_PAD_IF_INPUT,
 114                                                 MEDIA_LNK_FL_ENABLED);
 115                         if (ret)
 116                                 return ret;
 117                 }
 118
 119                 if (if_aud) {
 120                         ret = media_create_pad_link(tuner, TUNER_PAD_AUD_OUT,
 121                                                     if_aud,
 122                                                     IF_AUD_DEC_PAD_IF_INPUT,
 123                                                     MEDIA_LNK_FL_ENABLED);
 124                         if (ret)
 125                                 return ret;
 126                 } else {
 127                         if_aud = tuner;
 128                 }
 129
 130         }
 131
 132         /* Create demod to V4L, VBI and SDR radio links */
 133         if (io_v4l) {
 134                 ret = media_create_pad_link(decoder, DEMOD_PAD_VID_OUT,
 135                                         io_v4l, 0,
 136                                         MEDIA_LNK_FL_ENABLED);
 137                 if (ret)
 138                         return ret;
 139         }
 140
 141         if (io_swradio) {
 142                 ret = media_create_pad_link(decoder, DEMOD_PAD_VID_OUT,
 143                                         io_swradio, 0,
 144                                         MEDIA_LNK_FL_ENABLED);
 145                 if (ret)
 146                         return ret;
 147         }
 148
 149         if (io_vbi) {
 150                 ret = media_create_pad_link(decoder, DEMOD_PAD_VBI_OUT,
 151                                             io_vbi, 0,
 152                                             MEDIA_LNK_FL_ENABLED);
 153                 if (ret)
 154                         return ret;
 155         }
 156
 157         /* Create links for the media connectors */
 158         flags = MEDIA_LNK_FL_ENABLED;
 159         media_device_for_each_entity(entity, mdev) {
 160                 switch (entity->function) {
 161                 case MEDIA_ENT_F_CONN_RF:
 162                         if (!tuner)
 163                                 continue;
 164
 165                         ret = media_create_pad_link(entity, 0, tuner,
 166                                                     TUNER_PAD_RF_INPUT,
 167                                                     flags);
 168                         break;
 169                 case MEDIA_ENT_F_CONN_SVIDEO:
 170                 case MEDIA_ENT_F_CONN_COMPOSITE:
 171                         ret = media_create_pad_link(entity, 0, decoder,
 172                                                     DEMOD_PAD_IF_INPUT,
 173                                                     flags);
 174                         break;
 175                 default:
 176                         continue;
 177                 }
 178                 if (ret)
 179                         return ret;
 180
 181                 flags = 0;
 182         }
 183
 184         return 0;
 185 }
 186 EXPORT_SYMBOL_GPL(v4l2_mc_create_media_graph);
 187
 188 int v4l_enable_media_source(struct video_device *vdev)
 189 {
 190         struct media_device *mdev = vdev->entity.graph_obj.mdev;
 191         int ret = 0, err;
 192
 193         if (!mdev)
 194                 return 0;
 195
 196         mutex_lock(&mdev->graph_mutex);
 197         if (!mdev->enable_source)
 198                 goto end;
 199         err = mdev->enable_source(&vdev->entity, &vdev->pipe);
 200         if (err)
 201                 ret = -EBUSY;
 202 end:
 203         mutex_unlock(&mdev->graph_mutex);
 204         return ret;
 205 }
 206 EXPORT_SYMBOL_GPL(v4l_enable_media_source);
 207
 208 void v4l_disable_media_source(struct video_device *vdev)
 209 {
 210         struct media_device *mdev = vdev->entity.graph_obj.mdev;
 211
 212         if (mdev) {
 213                 mutex_lock(&mdev->graph_mutex);
 214                 if (mdev->disable_source)
 215                         mdev->disable_source(&vdev->entity);
 216                 mutex_unlock(&mdev->graph_mutex);
 217         }
 218 }
 219 EXPORT_SYMBOL_GPL(v4l_disable_media_source);
 220
 221 int v4l_vb2q_enable_media_source(struct vb2_queue *q)
 222 {
 223         struct v4l2_fh *fh = q->owner;
 224
 225         if (fh && fh->vdev)
 226                 return v4l_enable_media_source(fh->vdev);
 227         return 0;
 228 }
 229 EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
 230
 231 /* -----------------------------------------------------------------------------
 232  * Pipeline power management
 233  *
 234  * Entities must be powered up when part of a pipeline that contains at least
 235  * one open video device node.
 236  *
 237  * To achieve this use the entity use_count field to track the number of users.
 238  * For entities corresponding to video device nodes the use_count field stores
 239  * the users count of the node. For entities corresponding to subdevs the
 240  * use_count field stores the total number of users of all video device nodes
 241  * in the pipeline.
 242  *
 243  * The v4l2_pipeline_pm_use() function must be called in the open() and
 244  * close() handlers of video device nodes. It increments or decrements the use
 245  * count of all subdev entities in the pipeline.
 246  *
 247  * To react to link management on powered pipelines, the link setup notification
 248  * callback updates the use count of all entities in the source and sink sides
 249  * of the link.
 250  */
 251
 252 /*
 253  * pipeline_pm_use_count - Count the number of users of a pipeline
 254  * @entity: The entity
 255  *
 256  * Return the total number of users of all video device nodes in the pipeline.
 257  */
 258 static int pipeline_pm_use_count(struct media_entity *entity,
 259         struct media_graph *graph)
 260 {
 261         int use = 0;
 262
 263         media_graph_walk_start(graph, entity);
 264
 265         while ((entity = media_graph_walk_next(graph))) {
 266                 if (is_media_entity_v4l2_video_device(entity))
 267                         use += entity->use_count;
 268         }
 269
 270         return use;
 271 }
 272
 273 /*
 274  * pipeline_pm_power_one - Apply power change to an entity
 275  * @entity: The entity
 276  * @change: Use count change
 277  *
 278  * Change the entity use count by @change. If the entity is a subdev update its
 279  * power state by calling the core::s_power operation when the use count goes
 280  * from 0 to != 0 or from != 0 to 0.
 281  *
 282  * Return 0 on success or a negative error code on failure.
 283  */
 284 static int pipeline_pm_power_one(struct media_entity *entity, int change)
 285 {
 286         struct v4l2_subdev *subdev;
 287         int ret;
 288
 289         subdev = is_media_entity_v4l2_subdev(entity)
 290                ? media_entity_to_v4l2_subdev(entity) : NULL;
 291
 292         if (entity->use_count == 0 && change > 0 && subdev != NULL) {
 293                 ret = v4l2_subdev_call(subdev, core, s_power, 1);
 294                 if (ret < 0 && ret != -ENOIOCTLCMD)
 295                         return ret;
 296         }
 297
 298         entity->use_count += change;
 299         WARN_ON(entity->use_count < 0);
 300
 301         if (entity->use_count == 0 && change < 0 && subdev != NULL)
 302                 v4l2_subdev_call(subdev, core, s_power, 0);
 303
 304         return 0;
 305 }
 306
 307 /*
 308  * pipeline_pm_power - Apply power change to all entities in a pipeline
 309  * @entity: The entity
 310  * @change: Use count change
 311  *
 312  * Walk the pipeline to update the use count and the power state of all non-node
 313  * entities.
 314  *
 315  * Return 0 on success or a negative error code on failure.
 316  */
 317 static int pipeline_pm_power(struct media_entity *entity, int change,
 318         struct media_graph *graph)
 319 {
 320         struct media_entity *first = entity;
 321         int ret = 0;
 322
 323         if (!change)
 324                 return 0;
 325
 326         media_graph_walk_start(graph, entity);
 327
 328         while (!ret && (entity = media_graph_walk_next(graph)))
 329                 if (is_media_entity_v4l2_subdev(entity))
 330                         ret = pipeline_pm_power_one(entity, change);
 331
 332         if (!ret)
 333                 return ret;
 334
 335         media_graph_walk_start(graph, first);
 336
 337         while ((first = media_graph_walk_next(graph))
 338                && first != entity)
 339                 if (is_media_entity_v4l2_subdev(first))
 340                         pipeline_pm_power_one(first, -change);
 341
 342         return ret;
 343 }
 344
 345 int v4l2_pipeline_pm_use(struct media_entity *entity, int use)
 346 {
 347         struct media_device *mdev = entity->graph_obj.mdev;
 348         int change = use ? 1 : -1;
 349         int ret;
 350
 351         mutex_lock(&mdev->graph_mutex);
 352
 353         /* Apply use count to node. */
 354         entity->use_count += change;
 355         WARN_ON(entity->use_count < 0);
 356
 357         /* Apply power change to connected non-nodes. */
 358         ret = pipeline_pm_power(entity, change, &mdev->pm_count_walk);
 359         if (ret < 0)
 360                 entity->use_count -= change;
 361
 362         mutex_unlock(&mdev->graph_mutex);
 363
 364         return ret;
 365 }
 366 EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_use);
 367
 368 int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
 369                               unsigned int notification)
 370 {
 371         struct media_graph *graph = &link->graph_obj.mdev->pm_count_walk;
 372         struct media_entity *source = link->source->entity;
 373         struct media_entity *sink = link->sink->entity;
 374         int source_use;
 375         int sink_use;
 376         int ret = 0;
 377
 378         source_use = pipeline_pm_use_count(source, graph);
 379         sink_use = pipeline_pm_use_count(sink, graph);
 380
 381         if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH &&
 382             !(flags & MEDIA_LNK_FL_ENABLED)) {
 383                 /* Powering off entities is assumed to never fail. */
 384                 pipeline_pm_power(source, -sink_use, graph);
 385                 pipeline_pm_power(sink, -source_use, graph);
 386                 return 0;
 387         }
 388
 389         if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
 390                 (flags & MEDIA_LNK_FL_ENABLED)) {
 391
 392                 ret = pipeline_pm_power(source, sink_use, graph);
 393                 if (ret < 0)
 394                         return ret;
 395
 396                 ret = pipeline_pm_power(sink, source_use, graph);
 397                 if (ret < 0)
 398                         pipeline_pm_power(source, -sink_use, graph);
 399         }
 400
 401         return ret;
 402 }
 403 EXPORT_SYMBOL_GPL(v4l2_pipeline_link_notify);