drivers/media/v4l2-core/v4l2-mem2mem.c

   1 /*
   2  * Memory-to-memory device framework for Video for Linux 2 and videobuf.
   3  *
   4  * Helper functions for devices that use videobuf buffers for both their
   5  * source and destination.
   6  *
   7  * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
   8  * Pawel Osciak, <pawel@osciak.com>
   9  * Marek Szyprowski, <m.szyprowski@samsung.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by the
  13  * Free Software Foundation; either version 2 of the License, or (at your
  14  * option) any later version.
  15  */
  16 #include <linux/module.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/v4l2-mem2mem.h>
  22 #include <media/v4l2-dev.h>
  23 #include <media/v4l2-fh.h>
  24 #include <media/v4l2-event.h>
  25
  26 MODULE_DESCRIPTION("Mem to mem device framework for videobuf");
  27 MODULE_AUTHOR("Pawel Osciak, <pawel@osciak.com>");
  28 MODULE_LICENSE("GPL");
  29
  30 static bool debug;
  31 module_param(debug, bool, 0644);
  32
  33 #define dprintk(fmt, arg...)                                            \
  34         do {                                                            \
  35                 if (debug)                                              \
  36                         printk(KERN_DEBUG "%s: " fmt, __func__, ## arg);\
  37         } while (0)
  38
  39
  40 /* Instance is already queued on the job_queue */
  41 #define TRANS_QUEUED            (1 << 0)
  42 /* Instance is currently running in hardware */
  43 #define TRANS_RUNNING           (1 << 1)
  44 /* Instance is currently aborting */
  45 #define TRANS_ABORT             (1 << 2)
  46
  47
  48 /* Offset base for buffers on the destination queue - used to distinguish
  49  * between source and destination buffers when mmapping - they receive the same
  50  * offsets but for different queues */
  51 #define DST_QUEUE_OFF_BASE      (1 << 30)
  52
  53
  54 /**
  55  * struct v4l2_m2m_dev - per-device context
  56  * @curr_ctx:           currently running instance
  57  * @job_queue:          instances queued to run
  58  * @job_spinlock:       protects job_queue
  59  * @m2m_ops:            driver callbacks
  60  */
  61 struct v4l2_m2m_dev {
  62         struct v4l2_m2m_ctx     *curr_ctx;
  63
  64         struct list_head        job_queue;
  65         spinlock_t              job_spinlock;
  66
  67         const struct v4l2_m2m_ops *m2m_ops;
  68 };
  69
  70 static struct v4l2_m2m_queue_ctx *get_queue_ctx(struct v4l2_m2m_ctx *m2m_ctx,
  71                                                 enum v4l2_buf_type type)
  72 {
  73         if (V4L2_TYPE_IS_OUTPUT(type))
  74                 return &m2m_ctx->out_q_ctx;
  75         else
  76                 return &m2m_ctx->cap_q_ctx;
  77 }
  78
  79 /**
  80  * v4l2_m2m_get_vq() - return vb2_queue for the given type
  81  */
  82 struct vb2_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
  83                                        enum v4l2_buf_type type)
  84 {
  85         struct v4l2_m2m_queue_ctx *q_ctx;
  86
  87         q_ctx = get_queue_ctx(m2m_ctx, type);
  88         if (!q_ctx)
  89                 return NULL;
  90
  91         return &q_ctx->q;
  92 }
  93 EXPORT_SYMBOL(v4l2_m2m_get_vq);
  94
  95 /**
  96  * v4l2_m2m_next_buf() - return next buffer from the list of ready buffers
  97  */
  98 void *v4l2_m2m_next_buf(struct v4l2_m2m_queue_ctx *q_ctx)
  99 {
 100         struct v4l2_m2m_buffer *b;
 101         unsigned long flags;
 102
 103         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 104
 105         if (list_empty(&q_ctx->rdy_queue)) {
 106                 spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 107                 return NULL;
 108         }
 109
 110         b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
 111         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 112         return &b->vb;
 113 }
 114 EXPORT_SYMBOL_GPL(v4l2_m2m_next_buf);
 115
 116 /**
 117  * v4l2_m2m_buf_remove() - take off a buffer from the list of ready buffers and
 118  * return it
 119  */
 120 void *v4l2_m2m_buf_remove(struct v4l2_m2m_queue_ctx *q_ctx)
 121 {
 122         struct v4l2_m2m_buffer *b;
 123         unsigned long flags;
 124
 125         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 126         if (list_empty(&q_ctx->rdy_queue)) {
 127                 spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 128                 return NULL;
 129         }
 130         b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
 131         list_del(&b->list);
 132         q_ctx->num_rdy--;
 133         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 134
 135         return &b->vb;
 136 }
 137 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove);
 138
 139 /*
 140  * Scheduling handlers
 141  */
 142
 143 /**
 144  * v4l2_m2m_get_curr_priv() - return driver private data for the currently
 145  * running instance or NULL if no instance is running
 146  */
 147 void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev)
 148 {
 149         unsigned long flags;
 150         void *ret = NULL;
 151
 152         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 153         if (m2m_dev->curr_ctx)
 154                 ret = m2m_dev->curr_ctx->priv;
 155         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 156
 157         return ret;
 158 }
 159 EXPORT_SYMBOL(v4l2_m2m_get_curr_priv);
 160
 161 /**
 162  * v4l2_m2m_try_run() - select next job to perform and run it if possible
 163  *
 164  * Get next transaction (if present) from the waiting jobs list and run it.
 165  */
 166 static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
 167 {
 168         unsigned long flags;
 169
 170         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 171         if (NULL != m2m_dev->curr_ctx) {
 172                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 173                 dprintk("Another instance is running, won't run now\n");
 174                 return;
 175         }
 176
 177         if (list_empty(&m2m_dev->job_queue)) {
 178                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 179                 dprintk("No job pending\n");
 180                 return;
 181         }
 182
 183         m2m_dev->curr_ctx = list_first_entry(&m2m_dev->job_queue,
 184                                    struct v4l2_m2m_ctx, queue);
 185         m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING;
 186         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 187
 188         m2m_dev->m2m_ops->device_run(m2m_dev->curr_ctx->priv);
 189 }
 190
 191 /**
 192  * v4l2_m2m_try_schedule() - check whether an instance is ready to be added to
 193  * the pending job queue and add it if so.
 194  * @m2m_ctx:    m2m context assigned to the instance to be checked
 195  *
 196  * There are three basic requirements an instance has to meet to be able to run:
 197  * 1) at least one source buffer has to be queued,
 198  * 2) at least one destination buffer has to be queued,
 199  * 3) streaming has to be on.
 200  *
 201  * If a queue is buffered (for example a decoder hardware ringbuffer that has
 202  * to be drained before doing streamoff), allow scheduling without v4l2 buffers
 203  * on that queue.
 204  *
 205  * There may also be additional, custom requirements. In such case the driver
 206  * should supply a custom callback (job_ready in v4l2_m2m_ops) that should
 207  * return 1 if the instance is ready.
 208  * An example of the above could be an instance that requires more than one
 209  * src/dst buffer per transaction.
 210  */
 211 void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx)
 212 {
 213         struct v4l2_m2m_dev *m2m_dev;
 214         unsigned long flags_job, flags_out, flags_cap;
 215
 216         m2m_dev = m2m_ctx->m2m_dev;
 217         dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);
 218
 219         if (!m2m_ctx->out_q_ctx.q.streaming
 220             || !m2m_ctx->cap_q_ctx.q.streaming) {
 221                 dprintk("Streaming needs to be on for both queues\n");
 222                 return;
 223         }
 224
 225         spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
 226
 227         /* If the context is aborted then don't schedule it */
 228         if (m2m_ctx->job_flags & TRANS_ABORT) {
 229                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 230                 dprintk("Aborted context\n");
 231                 return;
 232         }
 233
 234         if (m2m_ctx->job_flags & TRANS_QUEUED) {
 235                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 236                 dprintk("On job queue already\n");
 237                 return;
 238         }
 239
 240         spin_lock_irqsave(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
 241         if (list_empty(&m2m_ctx->out_q_ctx.rdy_queue)
 242             && !m2m_ctx->out_q_ctx.buffered) {
 243                 spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock,
 244                                         flags_out);
 245                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 246                 dprintk("No input buffers available\n");
 247                 return;
 248         }
 249         spin_lock_irqsave(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
 250         if (list_empty(&m2m_ctx->cap_q_ctx.rdy_queue)
 251             && !m2m_ctx->cap_q_ctx.buffered) {
 252                 spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock,
 253                                         flags_cap);
 254                 spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock,
 255                                         flags_out);
 256                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 257                 dprintk("No output buffers available\n");
 258                 return;
 259         }
 260         spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
 261         spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
 262
 263         if (m2m_dev->m2m_ops->job_ready
 264                 && (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
 265                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 266                 dprintk("Driver not ready\n");
 267                 return;
 268         }
 269
 270         list_add_tail(&m2m_ctx->queue, &m2m_dev->job_queue);
 271         m2m_ctx->job_flags |= TRANS_QUEUED;
 272
 273         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 274
 275         v4l2_m2m_try_run(m2m_dev);
 276 }
 277 EXPORT_SYMBOL_GPL(v4l2_m2m_try_schedule);
 278
 279 /**
 280  * v4l2_m2m_cancel_job() - cancel pending jobs for the context
 281  *
 282  * In case of streamoff or release called on any context,
 283  * 1] If the context is currently running, then abort job will be called
 284  * 2] If the context is queued, then the context will be removed from
 285  *    the job_queue
 286  */
 287 static void v4l2_m2m_cancel_job(struct v4l2_m2m_ctx *m2m_ctx)
 288 {
 289         struct v4l2_m2m_dev *m2m_dev;
 290         unsigned long flags;
 291
 292         m2m_dev = m2m_ctx->m2m_dev;
 293         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 294
 295         m2m_ctx->job_flags |= TRANS_ABORT;
 296         if (m2m_ctx->job_flags & TRANS_RUNNING) {
 297                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 298                 m2m_dev->m2m_ops->job_abort(m2m_ctx->priv);
 299                 dprintk("m2m_ctx %p running, will wait to complete", m2m_ctx);
 300                 wait_event(m2m_ctx->finished,
 301                                 !(m2m_ctx->job_flags & TRANS_RUNNING));
 302         } else if (m2m_ctx->job_flags & TRANS_QUEUED) {
 303                 list_del(&m2m_ctx->queue);
 304                 m2m_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
 305                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 306                 dprintk("m2m_ctx: %p had been on queue and was removed\n",
 307                         m2m_ctx);
 308         } else {
 309                 /* Do nothing, was not on queue/running */
 310                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 311         }
 312 }
 313
 314 /**
 315  * v4l2_m2m_job_finish() - inform the framework that a job has been finished
 316  * and have it clean up
 317  *
 318  * Called by a driver to yield back the device after it has finished with it.
 319  * Should be called as soon as possible after reaching a state which allows
 320  * other instances to take control of the device.
 321  *
 322  * This function has to be called only after device_run() callback has been
 323  * called on the driver. To prevent recursion, it should not be called directly
 324  * from the device_run() callback though.
 325  */
 326 void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
 327                          struct v4l2_m2m_ctx *m2m_ctx)
 328 {
 329         unsigned long flags;
 330
 331         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 332         if (!m2m_dev->curr_ctx || m2m_dev->curr_ctx != m2m_ctx) {
 333                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 334                 dprintk("Called by an instance not currently running\n");
 335                 return;
 336         }
 337
 338         list_del(&m2m_dev->curr_ctx->queue);
 339         m2m_dev->curr_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
 340         wake_up(&m2m_dev->curr_ctx->finished);
 341         m2m_dev->curr_ctx = NULL;
 342
 343         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 344
 345         /* This instance might have more buffers ready, but since we do not
 346          * allow more than one job on the job_queue per instance, each has
 347          * to be scheduled separately after the previous one finishes. */
 348         v4l2_m2m_try_schedule(m2m_ctx);
 349         v4l2_m2m_try_run(m2m_dev);
 350 }
 351 EXPORT_SYMBOL(v4l2_m2m_job_finish);
 352
 353 /**
 354  * v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
 355  */
 356 int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 357                      struct v4l2_requestbuffers *reqbufs)
 358 {
 359         struct vb2_queue *vq;
 360         int ret;
 361
 362         vq = v4l2_m2m_get_vq(m2m_ctx, reqbufs->type);
 363         ret = vb2_reqbufs(vq, reqbufs);
 364         /* If count == 0, then the owner has released all buffers and he
 365            is no longer owner of the queue. Otherwise we have an owner. */
 366         if (ret == 0)
 367                 vq->owner = reqbufs->count ? file->private_data : NULL;
 368
 369         return ret;
 370 }
 371 EXPORT_SYMBOL_GPL(v4l2_m2m_reqbufs);
 372
 373 /**
 374  * v4l2_m2m_querybuf() - multi-queue-aware QUERYBUF multiplexer
 375  *
 376  * See v4l2_m2m_mmap() documentation for details.
 377  */
 378 int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 379                       struct v4l2_buffer *buf)
 380 {
 381         struct vb2_queue *vq;
 382         int ret = 0;
 383         unsigned int i;
 384
 385         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 386         ret = vb2_querybuf(vq, buf);
 387
 388         /* Adjust MMAP memory offsets for the CAPTURE queue */
 389         if (buf->memory == V4L2_MEMORY_MMAP && !V4L2_TYPE_IS_OUTPUT(vq->type)) {
 390                 if (V4L2_TYPE_IS_MULTIPLANAR(vq->type)) {
 391                         for (i = 0; i < buf->length; ++i)
 392                                 buf->m.planes[i].m.mem_offset
 393                                         += DST_QUEUE_OFF_BASE;
 394                 } else {
 395                         buf->m.offset += DST_QUEUE_OFF_BASE;
 396                 }
 397         }
 398
 399         return ret;
 400 }
 401 EXPORT_SYMBOL_GPL(v4l2_m2m_querybuf);
 402
 403 /**
 404  * v4l2_m2m_qbuf() - enqueue a source or destination buffer, depending on
 405  * the type
 406  */
 407 int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 408                   struct v4l2_buffer *buf)
 409 {
 410         struct vb2_queue *vq;
 411         int ret;
 412
 413         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 414         ret = vb2_qbuf(vq, buf);
 415         if (!ret)
 416                 v4l2_m2m_try_schedule(m2m_ctx);
 417
 418         return ret;
 419 }
 420 EXPORT_SYMBOL_GPL(v4l2_m2m_qbuf);
 421
 422 /**
 423  * v4l2_m2m_dqbuf() - dequeue a source or destination buffer, depending on
 424  * the type
 425  */
 426 int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 427                    struct v4l2_buffer *buf)
 428 {
 429         struct vb2_queue *vq;
 430
 431         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 432         return vb2_dqbuf(vq, buf, file->f_flags & O_NONBLOCK);
 433 }
 434 EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
 435
 436 /**
 437  * v4l2_m2m_prepare_buf() - prepare a source or destination buffer, depending on
 438  * the type
 439  */
 440 int v4l2_m2m_prepare_buf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 441                          struct v4l2_buffer *buf)
 442 {
 443         struct vb2_queue *vq;
 444         int ret;
 445
 446         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 447         ret = vb2_prepare_buf(vq, buf);
 448         if (!ret)
 449                 v4l2_m2m_try_schedule(m2m_ctx);
 450
 451         return ret;
 452 }
 453 EXPORT_SYMBOL_GPL(v4l2_m2m_prepare_buf);
 454
 455 /**
 456  * v4l2_m2m_create_bufs() - create a source or destination buffer, depending
 457  * on the type
 458  */
 459 int v4l2_m2m_create_bufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 460                          struct v4l2_create_buffers *create)
 461 {
 462         struct vb2_queue *vq;
 463
 464         vq = v4l2_m2m_get_vq(m2m_ctx, create->format.type);
 465         return vb2_create_bufs(vq, create);
 466 }
 467 EXPORT_SYMBOL_GPL(v4l2_m2m_create_bufs);
 468
 469 /**
 470  * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
 471  * the type
 472  */
 473 int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 474                   struct v4l2_exportbuffer *eb)
 475 {
 476         struct vb2_queue *vq;
 477
 478         vq = v4l2_m2m_get_vq(m2m_ctx, eb->type);
 479         return vb2_expbuf(vq, eb);
 480 }
 481 EXPORT_SYMBOL_GPL(v4l2_m2m_expbuf);
 482 /**
 483  * v4l2_m2m_streamon() - turn on streaming for a video queue
 484  */
 485 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 486                       enum v4l2_buf_type type)
 487 {
 488         struct vb2_queue *vq;
 489         int ret;
 490
 491         vq = v4l2_m2m_get_vq(m2m_ctx, type);
 492         ret = vb2_streamon(vq, type);
 493         if (!ret)
 494                 v4l2_m2m_try_schedule(m2m_ctx);
 495
 496         return ret;
 497 }
 498 EXPORT_SYMBOL_GPL(v4l2_m2m_streamon);
 499
 500 /**
 501  * v4l2_m2m_streamoff() - turn off streaming for a video queue
 502  */
 503 int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 504                        enum v4l2_buf_type type)
 505 {
 506         struct v4l2_m2m_dev *m2m_dev;
 507         struct v4l2_m2m_queue_ctx *q_ctx;
 508         unsigned long flags_job, flags;
 509         int ret;
 510
 511         /* wait until the current context is dequeued from job_queue */
 512         v4l2_m2m_cancel_job(m2m_ctx);
 513
 514         q_ctx = get_queue_ctx(m2m_ctx, type);
 515         ret = vb2_streamoff(&q_ctx->q, type);
 516         if (ret)
 517                 return ret;
 518
 519         m2m_dev = m2m_ctx->m2m_dev;
 520         spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
 521         /* We should not be scheduled anymore, since we're dropping a queue. */
 522         if (m2m_ctx->job_flags & TRANS_QUEUED)
 523                 list_del(&m2m_ctx->queue);
 524         m2m_ctx->job_flags = 0;
 525
 526         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 527         /* Drop queue, since streamoff returns device to the same state as after
 528          * calling reqbufs. */
 529         INIT_LIST_HEAD(&q_ctx->rdy_queue);
 530         q_ctx->num_rdy = 0;
 531         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 532
 533         if (m2m_dev->curr_ctx == m2m_ctx) {
 534                 m2m_dev->curr_ctx = NULL;
 535                 wake_up(&m2m_ctx->finished);
 536         }
 537         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 538
 539         return 0;
 540 }
 541 EXPORT_SYMBOL_GPL(v4l2_m2m_streamoff);
 542
 543 /**
 544  * v4l2_m2m_poll() - poll replacement, for destination buffers only
 545  *
 546  * Call from the driver's poll() function. Will poll both queues. If a buffer
 547  * is available to dequeue (with dqbuf) from the source queue, this will
 548  * indicate that a non-blocking write can be performed, while read will be
 549  * returned in case of the destination queue.
 550  */
 551 unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 552                            struct poll_table_struct *wait)
 553 {
 554         struct video_device *vfd = video_devdata(file);
 555         unsigned long req_events = poll_requested_events(wait);
 556         struct vb2_queue *src_q, *dst_q;
 557         struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;
 558         unsigned int rc = 0;
 559         unsigned long flags;
 560
 561         if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
 562                 struct v4l2_fh *fh = file->private_data;
 563
 564                 if (v4l2_event_pending(fh))
 565                         rc = POLLPRI;
 566                 else if (req_events & POLLPRI)
 567                         poll_wait(file, &fh->wait, wait);
 568                 if (!(req_events & (POLLOUT | POLLWRNORM | POLLIN | POLLRDNORM)))
 569                         return rc;
 570         }
 571
 572         src_q = v4l2_m2m_get_src_vq(m2m_ctx);
 573         dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);
 574
 575         /*
 576          * There has to be at least one buffer queued on each queued_list, which
 577          * means either in driver already or waiting for driver to claim it
 578          * and start processing.
 579          */
 580         if ((!src_q->streaming || list_empty(&src_q->queued_list))
 581                 && (!dst_q->streaming || list_empty(&dst_q->queued_list))) {
 582                 rc |= POLLERR;
 583                 goto end;
 584         }
 585
 586         if (m2m_ctx->m2m_dev->m2m_ops->unlock)
 587                 m2m_ctx->m2m_dev->m2m_ops->unlock(m2m_ctx->priv);
 588         else if (m2m_ctx->q_lock)
 589                 mutex_unlock(m2m_ctx->q_lock);
 590
 591         if (list_empty(&src_q->done_list))
 592                 poll_wait(file, &src_q->done_wq, wait);
 593         if (list_empty(&dst_q->done_list)) {
 594                 /*
 595                  * If the last buffer was dequeued from the capture queue,
 596                  * return immediately. DQBUF will return -EPIPE.
 597                  */
 598                 if (dst_q->last_buffer_dequeued)
 599                         return rc | POLLIN | POLLRDNORM;
 600
 601                 poll_wait(file, &dst_q->done_wq, wait);
 602         }
 603
 604         if (m2m_ctx->m2m_dev->m2m_ops->lock)
 605                 m2m_ctx->m2m_dev->m2m_ops->lock(m2m_ctx->priv);
 606         else if (m2m_ctx->q_lock) {
 607                 if (mutex_lock_interruptible(m2m_ctx->q_lock)) {
 608                         rc |= POLLERR;
 609                         goto end;
 610                 }
 611         }
 612
 613         spin_lock_irqsave(&src_q->done_lock, flags);
 614         if (!list_empty(&src_q->done_list))
 615                 src_vb = list_first_entry(&src_q->done_list, struct vb2_buffer,
 616                                                 done_entry);
 617         if (src_vb && (src_vb->state == VB2_BUF_STATE_DONE
 618                         || src_vb->state == VB2_BUF_STATE_ERROR))
 619                 rc |= POLLOUT | POLLWRNORM;
 620         spin_unlock_irqrestore(&src_q->done_lock, flags);
 621
 622         spin_lock_irqsave(&dst_q->done_lock, flags);
 623         if (!list_empty(&dst_q->done_list))
 624                 dst_vb = list_first_entry(&dst_q->done_list, struct vb2_buffer,
 625                                                 done_entry);
 626         if (dst_vb && (dst_vb->state == VB2_BUF_STATE_DONE
 627                         || dst_vb->state == VB2_BUF_STATE_ERROR))
 628                 rc |= POLLIN | POLLRDNORM;
 629         spin_unlock_irqrestore(&dst_q->done_lock, flags);
 630
 631 end:
 632         return rc;
 633 }
 634 EXPORT_SYMBOL_GPL(v4l2_m2m_poll);
 635
 636 /**
 637  * v4l2_m2m_mmap() - source and destination queues-aware mmap multiplexer
 638  *
 639  * Call from driver's mmap() function. Will handle mmap() for both queues
 640  * seamlessly for videobuffer, which will receive normal per-queue offsets and
 641  * proper videobuf queue pointers. The differentiation is made outside videobuf
 642  * by adding a predefined offset to buffers from one of the queues and
 643  * subtracting it before passing it back to videobuf. Only drivers (and
 644  * thus applications) receive modified offsets.
 645  */
 646 int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 647                          struct vm_area_struct *vma)
 648 {
 649         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 650         struct vb2_queue *vq;
 651
 652         if (offset < DST_QUEUE_OFF_BASE) {
 653                 vq = v4l2_m2m_get_src_vq(m2m_ctx);
 654         } else {
 655                 vq = v4l2_m2m_get_dst_vq(m2m_ctx);
 656                 vma->vm_pgoff -= (DST_QUEUE_OFF_BASE >> PAGE_SHIFT);
 657         }
 658
 659         return vb2_mmap(vq, vma);
 660 }
 661 EXPORT_SYMBOL(v4l2_m2m_mmap);
 662
 663 /**
 664  * v4l2_m2m_init() - initialize per-driver m2m data
 665  *
 666  * Usually called from driver's probe() function.
 667  */
 668 struct v4l2_m2m_dev *v4l2_m2m_init(const struct v4l2_m2m_ops *m2m_ops)
 669 {
 670         struct v4l2_m2m_dev *m2m_dev;
 671
 672         if (!m2m_ops || WARN_ON(!m2m_ops->device_run) ||
 673                         WARN_ON(!m2m_ops->job_abort))
 674                 return ERR_PTR(-EINVAL);
 675
 676         m2m_dev = kzalloc(sizeof *m2m_dev, GFP_KERNEL);
 677         if (!m2m_dev)
 678                 return ERR_PTR(-ENOMEM);
 679
 680         m2m_dev->curr_ctx = NULL;
 681         m2m_dev->m2m_ops = m2m_ops;
 682         INIT_LIST_HEAD(&m2m_dev->job_queue);
 683         spin_lock_init(&m2m_dev->job_spinlock);
 684
 685         return m2m_dev;
 686 }
 687 EXPORT_SYMBOL_GPL(v4l2_m2m_init);
 688
 689 /**
 690  * v4l2_m2m_release() - cleans up and frees a m2m_dev structure
 691  *
 692  * Usually called from driver's remove() function.
 693  */
 694 void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev)
 695 {
 696         kfree(m2m_dev);
 697 }
 698 EXPORT_SYMBOL_GPL(v4l2_m2m_release);
 699
 700 /**
 701  * v4l2_m2m_ctx_init() - allocate and initialize a m2m context
 702  * @priv - driver's instance private data
 703  * @m2m_dev - a previously initialized m2m_dev struct
 704  * @vq_init - a callback for queue type-specific initialization function to be
 705  * used for initializing videobuf_queues
 706  *
 707  * Usually called from driver's open() function.
 708  */
 709 struct v4l2_m2m_ctx *v4l2_m2m_ctx_init(struct v4l2_m2m_dev *m2m_dev,
 710                 void *drv_priv,
 711                 int (*queue_init)(void *priv, struct vb2_queue *src_vq, struct vb2_queue *dst_vq))
 712 {
 713         struct v4l2_m2m_ctx *m2m_ctx;
 714         struct v4l2_m2m_queue_ctx *out_q_ctx, *cap_q_ctx;
 715         int ret;
 716
 717         m2m_ctx = kzalloc(sizeof *m2m_ctx, GFP_KERNEL);
 718         if (!m2m_ctx)
 719                 return ERR_PTR(-ENOMEM);
 720
 721         m2m_ctx->priv = drv_priv;
 722         m2m_ctx->m2m_dev = m2m_dev;
 723         init_waitqueue_head(&m2m_ctx->finished);
 724
 725         out_q_ctx = &m2m_ctx->out_q_ctx;
 726         cap_q_ctx = &m2m_ctx->cap_q_ctx;
 727
 728         INIT_LIST_HEAD(&out_q_ctx->rdy_queue);
 729         INIT_LIST_HEAD(&cap_q_ctx->rdy_queue);
 730         spin_lock_init(&out_q_ctx->rdy_spinlock);
 731         spin_lock_init(&cap_q_ctx->rdy_spinlock);
 732
 733         INIT_LIST_HEAD(&m2m_ctx->queue);
 734
 735         ret = queue_init(drv_priv, &out_q_ctx->q, &cap_q_ctx->q);
 736
 737         if (ret)
 738                 goto err;
 739         /*
 740          * If both queues use same mutex assign it as the common buffer
 741          * queues lock to the m2m context. This lock is used in the
 742          * v4l2_m2m_ioctl_* helpers.
 743          */
 744         if (out_q_ctx->q.lock == cap_q_ctx->q.lock)
 745                 m2m_ctx->q_lock = out_q_ctx->q.lock;
 746
 747         return m2m_ctx;
 748 err:
 749         kfree(m2m_ctx);
 750         return ERR_PTR(ret);
 751 }
 752 EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_init);
 753
 754 /**
 755  * v4l2_m2m_ctx_release() - release m2m context
 756  *
 757  * Usually called from driver's release() function.
 758  */
 759 void v4l2_m2m_ctx_release(struct v4l2_m2m_ctx *m2m_ctx)
 760 {
 761         /* wait until the current context is dequeued from job_queue */
 762         v4l2_m2m_cancel_job(m2m_ctx);
 763
 764         vb2_queue_release(&m2m_ctx->cap_q_ctx.q);
 765         vb2_queue_release(&m2m_ctx->out_q_ctx.q);
 766
 767         kfree(m2m_ctx);
 768 }
 769 EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_release);
 770
 771 /**
 772  * v4l2_m2m_buf_queue() - add a buffer to the proper ready buffers list.
 773  *
 774  * Call from buf_queue(), videobuf_queue_ops callback.
 775  */
 776 void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx, struct vb2_buffer *vb)
 777 {
 778         struct v4l2_m2m_buffer *b = container_of(vb, struct v4l2_m2m_buffer, vb);
 779         struct v4l2_m2m_queue_ctx *q_ctx;
 780         unsigned long flags;
 781
 782         q_ctx = get_queue_ctx(m2m_ctx, vb->vb2_queue->type);
 783         if (!q_ctx)
 784                 return;
 785
 786         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 787         list_add_tail(&b->list, &q_ctx->rdy_queue);
 788         q_ctx->num_rdy++;
 789         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 790 }
 791 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_queue);
 792
 793 /* Videobuf2 ioctl helpers */
 794
 795 int v4l2_m2m_ioctl_reqbufs(struct file *file, void *priv,
 796                                 struct v4l2_requestbuffers *rb)
 797 {
 798         struct v4l2_fh *fh = file->private_data;
 799
 800         return v4l2_m2m_reqbufs(file, fh->m2m_ctx, rb);
 801 }
 802 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_reqbufs);
 803
 804 int v4l2_m2m_ioctl_create_bufs(struct file *file, void *priv,
 805                                 struct v4l2_create_buffers *create)
 806 {
 807         struct v4l2_fh *fh = file->private_data;
 808
 809         return v4l2_m2m_create_bufs(file, fh->m2m_ctx, create);
 810 }
 811 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_create_bufs);
 812
 813 int v4l2_m2m_ioctl_querybuf(struct file *file, void *priv,
 814                                 struct v4l2_buffer *buf)
 815 {
 816         struct v4l2_fh *fh = file->private_data;
 817
 818         return v4l2_m2m_querybuf(file, fh->m2m_ctx, buf);
 819 }
 820 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_querybuf);
 821
 822 int v4l2_m2m_ioctl_qbuf(struct file *file, void *priv,
 823                                 struct v4l2_buffer *buf)
 824 {
 825         struct v4l2_fh *fh = file->private_data;
 826
 827         return v4l2_m2m_qbuf(file, fh->m2m_ctx, buf);
 828 }
 829 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_qbuf);
 830
 831 int v4l2_m2m_ioctl_dqbuf(struct file *file, void *priv,
 832                                 struct v4l2_buffer *buf)
 833 {
 834         struct v4l2_fh *fh = file->private_data;
 835
 836         return v4l2_m2m_dqbuf(file, fh->m2m_ctx, buf);
 837 }
 838 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_dqbuf);
 839
 840 int v4l2_m2m_ioctl_prepare_buf(struct file *file, void *priv,
 841                                struct v4l2_buffer *buf)
 842 {
 843         struct v4l2_fh *fh = file->private_data;
 844
 845         return v4l2_m2m_prepare_buf(file, fh->m2m_ctx, buf);
 846 }
 847 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_prepare_buf);
 848
 849 int v4l2_m2m_ioctl_expbuf(struct file *file, void *priv,
 850                                 struct v4l2_exportbuffer *eb)
 851 {
 852         struct v4l2_fh *fh = file->private_data;
 853
 854         return v4l2_m2m_expbuf(file, fh->m2m_ctx, eb);
 855 }
 856 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_expbuf);
 857
 858 int v4l2_m2m_ioctl_streamon(struct file *file, void *priv,
 859                                 enum v4l2_buf_type type)
 860 {
 861         struct v4l2_fh *fh = file->private_data;
 862
 863         return v4l2_m2m_streamon(file, fh->m2m_ctx, type);
 864 }
 865 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_streamon);
 866
 867 int v4l2_m2m_ioctl_streamoff(struct file *file, void *priv,
 868                                 enum v4l2_buf_type type)
 869 {
 870         struct v4l2_fh *fh = file->private_data;
 871
 872         return v4l2_m2m_streamoff(file, fh->m2m_ctx, type);
 873 }
 874 EXPORT_SYMBOL_GPL(v4l2_m2m_ioctl_streamoff);
 875
 876 /*
 877  * v4l2_file_operations helpers. It is assumed here same lock is used
 878  * for the output and the capture buffer queue.
 879  */
 880
 881 int v4l2_m2m_fop_mmap(struct file *file, struct vm_area_struct *vma)
 882 {
 883         struct v4l2_fh *fh = file->private_data;
 884
 885         return v4l2_m2m_mmap(file, fh->m2m_ctx, vma);
 886 }
 887 EXPORT_SYMBOL_GPL(v4l2_m2m_fop_mmap);
 888
 889 unsigned int v4l2_m2m_fop_poll(struct file *file, poll_table *wait)
 890 {
 891         struct v4l2_fh *fh = file->private_data;
 892         struct v4l2_m2m_ctx *m2m_ctx = fh->m2m_ctx;
 893         unsigned int ret;
 894
 895         if (m2m_ctx->q_lock)
 896                 mutex_lock(m2m_ctx->q_lock);
 897
 898         ret = v4l2_m2m_poll(file, m2m_ctx, wait);
 899
 900         if (m2m_ctx->q_lock)
 901                 mutex_unlock(m2m_ctx->q_lock);
 902
 903         return ret;
 904 }
 905 EXPORT_SYMBOL_GPL(v4l2_m2m_fop_poll);
 906