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
  45
  46 /* Offset base for buffers on the destination queue - used to distinguish
  47  * between source and destination buffers when mmapping - they receive the same
  48  * offsets but for different queues */
  49 #define DST_QUEUE_OFF_BASE      (1 << 30)
  50
  51
  52 /**
  53  * struct v4l2_m2m_dev - per-device context
  54  * @curr_ctx:           currently running instance
  55  * @job_queue:          instances queued to run
  56  * @job_spinlock:       protects job_queue
  57  * @m2m_ops:            driver callbacks
  58  */
  59 struct v4l2_m2m_dev {
  60         struct v4l2_m2m_ctx     *curr_ctx;
  61
  62         struct list_head        job_queue;
  63         spinlock_t              job_spinlock;
  64
  65         const struct v4l2_m2m_ops *m2m_ops;
  66 };
  67
  68 static struct v4l2_m2m_queue_ctx *get_queue_ctx(struct v4l2_m2m_ctx *m2m_ctx,
  69                                                 enum v4l2_buf_type type)
  70 {
  71         if (V4L2_TYPE_IS_OUTPUT(type))
  72                 return &m2m_ctx->out_q_ctx;
  73         else
  74                 return &m2m_ctx->cap_q_ctx;
  75 }
  76
  77 /**
  78  * v4l2_m2m_get_vq() - return vb2_queue for the given type
  79  */
  80 struct vb2_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
  81                                        enum v4l2_buf_type type)
  82 {
  83         struct v4l2_m2m_queue_ctx *q_ctx;
  84
  85         q_ctx = get_queue_ctx(m2m_ctx, type);
  86         if (!q_ctx)
  87                 return NULL;
  88
  89         return &q_ctx->q;
  90 }
  91 EXPORT_SYMBOL(v4l2_m2m_get_vq);
  92
  93 /**
  94  * v4l2_m2m_next_buf() - return next buffer from the list of ready buffers
  95  */
  96 void *v4l2_m2m_next_buf(struct v4l2_m2m_queue_ctx *q_ctx)
  97 {
  98         struct v4l2_m2m_buffer *b = NULL;
  99         unsigned long flags;
 100
 101         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 102
 103         if (list_empty(&q_ctx->rdy_queue)) {
 104                 spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 105                 return NULL;
 106         }
 107
 108         b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
 109         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 110         return &b->vb;
 111 }
 112 EXPORT_SYMBOL_GPL(v4l2_m2m_next_buf);
 113
 114 /**
 115  * v4l2_m2m_buf_remove() - take off a buffer from the list of ready buffers and
 116  * return it
 117  */
 118 void *v4l2_m2m_buf_remove(struct v4l2_m2m_queue_ctx *q_ctx)
 119 {
 120         struct v4l2_m2m_buffer *b = NULL;
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 124         if (list_empty(&q_ctx->rdy_queue)) {
 125                 spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 126                 return NULL;
 127         }
 128         b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
 129         list_del(&b->list);
 130         q_ctx->num_rdy--;
 131         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 132
 133         return &b->vb;
 134 }
 135 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove);
 136
 137 /*
 138  * Scheduling handlers
 139  */
 140
 141 /**
 142  * v4l2_m2m_get_curr_priv() - return driver private data for the currently
 143  * running instance or NULL if no instance is running
 144  */
 145 void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev)
 146 {
 147         unsigned long flags;
 148         void *ret = NULL;
 149
 150         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 151         if (m2m_dev->curr_ctx)
 152                 ret = m2m_dev->curr_ctx->priv;
 153         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 154
 155         return ret;
 156 }
 157 EXPORT_SYMBOL(v4l2_m2m_get_curr_priv);
 158
 159 /**
 160  * v4l2_m2m_try_run() - select next job to perform and run it if possible
 161  *
 162  * Get next transaction (if present) from the waiting jobs list and run it.
 163  */
 164 static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
 165 {
 166         unsigned long flags;
 167
 168         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 169         if (NULL != m2m_dev->curr_ctx) {
 170                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 171                 dprintk("Another instance is running, won't run now\n");
 172                 return;
 173         }
 174
 175         if (list_empty(&m2m_dev->job_queue)) {
 176                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 177                 dprintk("No job pending\n");
 178                 return;
 179         }
 180
 181         m2m_dev->curr_ctx = list_first_entry(&m2m_dev->job_queue,
 182                                    struct v4l2_m2m_ctx, queue);
 183         m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING;
 184         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 185
 186         m2m_dev->m2m_ops->device_run(m2m_dev->curr_ctx->priv);
 187 }
 188
 189 /**
 190  * v4l2_m2m_try_schedule() - check whether an instance is ready to be added to
 191  * the pending job queue and add it if so.
 192  * @m2m_ctx:    m2m context assigned to the instance to be checked
 193  *
 194  * There are three basic requirements an instance has to meet to be able to run:
 195  * 1) at least one source buffer has to be queued,
 196  * 2) at least one destination buffer has to be queued,
 197  * 3) streaming has to be on.
 198  *
 199  * If a queue is buffered (for example a decoder hardware ringbuffer that has
 200  * to be drained before doing streamoff), allow scheduling without v4l2 buffers
 201  * on that queue.
 202  *
 203  * There may also be additional, custom requirements. In such case the driver
 204  * should supply a custom callback (job_ready in v4l2_m2m_ops) that should
 205  * return 1 if the instance is ready.
 206  * An example of the above could be an instance that requires more than one
 207  * src/dst buffer per transaction.
 208  */
 209 static void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx)
 210 {
 211         struct v4l2_m2m_dev *m2m_dev;
 212         unsigned long flags_job, flags_out, flags_cap;
 213
 214         m2m_dev = m2m_ctx->m2m_dev;
 215         dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);
 216
 217         if (!m2m_ctx->out_q_ctx.q.streaming
 218             || !m2m_ctx->cap_q_ctx.q.streaming) {
 219                 dprintk("Streaming needs to be on for both queues\n");
 220                 return;
 221         }
 222
 223         spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
 224         if (m2m_ctx->job_flags & TRANS_QUEUED) {
 225                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 226                 dprintk("On job queue already\n");
 227                 return;
 228         }
 229
 230         spin_lock_irqsave(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
 231         if (list_empty(&m2m_ctx->out_q_ctx.rdy_queue)
 232             && !m2m_ctx->out_q_ctx.buffered) {
 233                 spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock,
 234                                         flags_out);
 235                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 236                 dprintk("No input buffers available\n");
 237                 return;
 238         }
 239         spin_lock_irqsave(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
 240         if (list_empty(&m2m_ctx->cap_q_ctx.rdy_queue)
 241             && !m2m_ctx->cap_q_ctx.buffered) {
 242                 spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock,
 243                                         flags_cap);
 244                 spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock,
 245                                         flags_out);
 246                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 247                 dprintk("No output buffers available\n");
 248                 return;
 249         }
 250         spin_unlock_irqrestore(&m2m_ctx->cap_q_ctx.rdy_spinlock, flags_cap);
 251         spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags_out);
 252
 253         if (m2m_dev->m2m_ops->job_ready
 254                 && (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
 255                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 256                 dprintk("Driver not ready\n");
 257                 return;
 258         }
 259
 260         list_add_tail(&m2m_ctx->queue, &m2m_dev->job_queue);
 261         m2m_ctx->job_flags |= TRANS_QUEUED;
 262
 263         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 264
 265         v4l2_m2m_try_run(m2m_dev);
 266 }
 267
 268 /**
 269  * v4l2_m2m_cancel_job() - cancel pending jobs for the context
 270  *
 271  * In case of streamoff or release called on any context,
 272  * 1] If the context is currently running, then abort job will be called
 273  * 2] If the context is queued, then the context will be removed from
 274  *    the job_queue
 275  */
 276 static void v4l2_m2m_cancel_job(struct v4l2_m2m_ctx *m2m_ctx)
 277 {
 278         struct v4l2_m2m_dev *m2m_dev;
 279         unsigned long flags;
 280
 281         m2m_dev = m2m_ctx->m2m_dev;
 282         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 283         if (m2m_ctx->job_flags & TRANS_RUNNING) {
 284                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 285                 m2m_dev->m2m_ops->job_abort(m2m_ctx->priv);
 286                 dprintk("m2m_ctx %p running, will wait to complete", m2m_ctx);
 287                 wait_event(m2m_ctx->finished,
 288                                 !(m2m_ctx->job_flags & TRANS_RUNNING));
 289         } else if (m2m_ctx->job_flags & TRANS_QUEUED) {
 290                 list_del(&m2m_ctx->queue);
 291                 m2m_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
 292                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 293                 dprintk("m2m_ctx: %p had been on queue and was removed\n",
 294                         m2m_ctx);
 295         } else {
 296                 /* Do nothing, was not on queue/running */
 297                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 298         }
 299 }
 300
 301 /**
 302  * v4l2_m2m_job_finish() - inform the framework that a job has been finished
 303  * and have it clean up
 304  *
 305  * Called by a driver to yield back the device after it has finished with it.
 306  * Should be called as soon as possible after reaching a state which allows
 307  * other instances to take control of the device.
 308  *
 309  * This function has to be called only after device_run() callback has been
 310  * called on the driver. To prevent recursion, it should not be called directly
 311  * from the device_run() callback though.
 312  */
 313 void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
 314                          struct v4l2_m2m_ctx *m2m_ctx)
 315 {
 316         unsigned long flags;
 317
 318         spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
 319         if (!m2m_dev->curr_ctx || m2m_dev->curr_ctx != m2m_ctx) {
 320                 spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 321                 dprintk("Called by an instance not currently running\n");
 322                 return;
 323         }
 324
 325         list_del(&m2m_dev->curr_ctx->queue);
 326         m2m_dev->curr_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
 327         wake_up(&m2m_dev->curr_ctx->finished);
 328         m2m_dev->curr_ctx = NULL;
 329
 330         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
 331
 332         /* This instance might have more buffers ready, but since we do not
 333          * allow more than one job on the job_queue per instance, each has
 334          * to be scheduled separately after the previous one finishes. */
 335         v4l2_m2m_try_schedule(m2m_ctx);
 336         v4l2_m2m_try_run(m2m_dev);
 337 }
 338 EXPORT_SYMBOL(v4l2_m2m_job_finish);
 339
 340 /**
 341  * v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
 342  */
 343 int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 344                      struct v4l2_requestbuffers *reqbufs)
 345 {
 346         struct vb2_queue *vq;
 347
 348         vq = v4l2_m2m_get_vq(m2m_ctx, reqbufs->type);
 349         return vb2_reqbufs(vq, reqbufs);
 350 }
 351 EXPORT_SYMBOL_GPL(v4l2_m2m_reqbufs);
 352
 353 /**
 354  * v4l2_m2m_querybuf() - multi-queue-aware QUERYBUF multiplexer
 355  *
 356  * See v4l2_m2m_mmap() documentation for details.
 357  */
 358 int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 359                       struct v4l2_buffer *buf)
 360 {
 361         struct vb2_queue *vq;
 362         int ret = 0;
 363         unsigned int i;
 364
 365         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 366         ret = vb2_querybuf(vq, buf);
 367
 368         /* Adjust MMAP memory offsets for the CAPTURE queue */
 369         if (buf->memory == V4L2_MEMORY_MMAP && !V4L2_TYPE_IS_OUTPUT(vq->type)) {
 370                 if (V4L2_TYPE_IS_MULTIPLANAR(vq->type)) {
 371                         for (i = 0; i < buf->length; ++i)
 372                                 buf->m.planes[i].m.mem_offset
 373                                         += DST_QUEUE_OFF_BASE;
 374                 } else {
 375                         buf->m.offset += DST_QUEUE_OFF_BASE;
 376                 }
 377         }
 378
 379         return ret;
 380 }
 381 EXPORT_SYMBOL_GPL(v4l2_m2m_querybuf);
 382
 383 /**
 384  * v4l2_m2m_qbuf() - enqueue a source or destination buffer, depending on
 385  * the type
 386  */
 387 int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 388                   struct v4l2_buffer *buf)
 389 {
 390         struct vb2_queue *vq;
 391         int ret;
 392
 393         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 394         ret = vb2_qbuf(vq, buf);
 395         if (!ret)
 396                 v4l2_m2m_try_schedule(m2m_ctx);
 397
 398         return ret;
 399 }
 400 EXPORT_SYMBOL_GPL(v4l2_m2m_qbuf);
 401
 402 /**
 403  * v4l2_m2m_dqbuf() - dequeue a source or destination buffer, depending on
 404  * the type
 405  */
 406 int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 407                    struct v4l2_buffer *buf)
 408 {
 409         struct vb2_queue *vq;
 410
 411         vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
 412         return vb2_dqbuf(vq, buf, file->f_flags & O_NONBLOCK);
 413 }
 414 EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);
 415
 416 /**
 417  * v4l2_m2m_create_bufs() - create a source or destination buffer, depending
 418  * on the type
 419  */
 420 int v4l2_m2m_create_bufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 421                          struct v4l2_create_buffers *create)
 422 {
 423         struct vb2_queue *vq;
 424
 425         vq = v4l2_m2m_get_vq(m2m_ctx, create->format.type);
 426         return vb2_create_bufs(vq, create);
 427 }
 428 EXPORT_SYMBOL_GPL(v4l2_m2m_create_bufs);
 429
 430 /**
 431  * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
 432  * the type
 433  */
 434 int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 435                   struct v4l2_exportbuffer *eb)
 436 {
 437         struct vb2_queue *vq;
 438
 439         vq = v4l2_m2m_get_vq(m2m_ctx, eb->type);
 440         return vb2_expbuf(vq, eb);
 441 }
 442 EXPORT_SYMBOL_GPL(v4l2_m2m_expbuf);
 443 /**
 444  * v4l2_m2m_streamon() - turn on streaming for a video queue
 445  */
 446 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 447                       enum v4l2_buf_type type)
 448 {
 449         struct vb2_queue *vq;
 450         int ret;
 451
 452         vq = v4l2_m2m_get_vq(m2m_ctx, type);
 453         ret = vb2_streamon(vq, type);
 454         if (!ret)
 455                 v4l2_m2m_try_schedule(m2m_ctx);
 456
 457         return ret;
 458 }
 459 EXPORT_SYMBOL_GPL(v4l2_m2m_streamon);
 460
 461 /**
 462  * v4l2_m2m_streamoff() - turn off streaming for a video queue
 463  */
 464 int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 465                        enum v4l2_buf_type type)
 466 {
 467         struct v4l2_m2m_dev *m2m_dev;
 468         struct v4l2_m2m_queue_ctx *q_ctx;
 469         unsigned long flags_job, flags;
 470         int ret;
 471
 472         /* wait until the current context is dequeued from job_queue */
 473         v4l2_m2m_cancel_job(m2m_ctx);
 474
 475         q_ctx = get_queue_ctx(m2m_ctx, type);
 476         ret = vb2_streamoff(&q_ctx->q, type);
 477         if (ret)
 478                 return ret;
 479
 480         m2m_dev = m2m_ctx->m2m_dev;
 481         spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
 482         /* We should not be scheduled anymore, since we're dropping a queue. */
 483         INIT_LIST_HEAD(&m2m_ctx->queue);
 484         m2m_ctx->job_flags = 0;
 485
 486         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 487         /* Drop queue, since streamoff returns device to the same state as after
 488          * calling reqbufs. */
 489         INIT_LIST_HEAD(&q_ctx->rdy_queue);
 490         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 491
 492         if (m2m_dev->curr_ctx == m2m_ctx) {
 493                 m2m_dev->curr_ctx = NULL;
 494                 wake_up(&m2m_ctx->finished);
 495         }
 496         spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
 497
 498         return 0;
 499 }
 500 EXPORT_SYMBOL_GPL(v4l2_m2m_streamoff);
 501
 502 /**
 503  * v4l2_m2m_poll() - poll replacement, for destination buffers only
 504  *
 505  * Call from the driver's poll() function. Will poll both queues. If a buffer
 506  * is available to dequeue (with dqbuf) from the source queue, this will
 507  * indicate that a non-blocking write can be performed, while read will be
 508  * returned in case of the destination queue.
 509  */
 510 unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 511                            struct poll_table_struct *wait)
 512 {
 513         struct video_device *vfd = video_devdata(file);
 514         unsigned long req_events = poll_requested_events(wait);
 515         struct vb2_queue *src_q, *dst_q;
 516         struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;
 517         unsigned int rc = 0;
 518         unsigned long flags;
 519
 520         if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
 521                 struct v4l2_fh *fh = file->private_data;
 522
 523                 if (v4l2_event_pending(fh))
 524                         rc = POLLPRI;
 525                 else if (req_events & POLLPRI)
 526                         poll_wait(file, &fh->wait, wait);
 527                 if (!(req_events & (POLLOUT | POLLWRNORM | POLLIN | POLLRDNORM)))
 528                         return rc;
 529         }
 530
 531         src_q = v4l2_m2m_get_src_vq(m2m_ctx);
 532         dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);
 533
 534         /*
 535          * There has to be at least one buffer queued on each queued_list, which
 536          * means either in driver already or waiting for driver to claim it
 537          * and start processing.
 538          */
 539         if ((!src_q->streaming || list_empty(&src_q->queued_list))
 540                 && (!dst_q->streaming || list_empty(&dst_q->queued_list))) {
 541                 rc |= POLLERR;
 542                 goto end;
 543         }
 544
 545         if (m2m_ctx->m2m_dev->m2m_ops->unlock)
 546                 m2m_ctx->m2m_dev->m2m_ops->unlock(m2m_ctx->priv);
 547
 548         if (list_empty(&src_q->done_list))
 549                 poll_wait(file, &src_q->done_wq, wait);
 550         if (list_empty(&dst_q->done_list))
 551                 poll_wait(file, &dst_q->done_wq, wait);
 552
 553         if (m2m_ctx->m2m_dev->m2m_ops->lock)
 554                 m2m_ctx->m2m_dev->m2m_ops->lock(m2m_ctx->priv);
 555
 556         spin_lock_irqsave(&src_q->done_lock, flags);
 557         if (!list_empty(&src_q->done_list))
 558                 src_vb = list_first_entry(&src_q->done_list, struct vb2_buffer,
 559                                                 done_entry);
 560         if (src_vb && (src_vb->state == VB2_BUF_STATE_DONE
 561                         || src_vb->state == VB2_BUF_STATE_ERROR))
 562                 rc |= POLLOUT | POLLWRNORM;
 563         spin_unlock_irqrestore(&src_q->done_lock, flags);
 564
 565         spin_lock_irqsave(&dst_q->done_lock, flags);
 566         if (!list_empty(&dst_q->done_list))
 567                 dst_vb = list_first_entry(&dst_q->done_list, struct vb2_buffer,
 568                                                 done_entry);
 569         if (dst_vb && (dst_vb->state == VB2_BUF_STATE_DONE
 570                         || dst_vb->state == VB2_BUF_STATE_ERROR))
 571                 rc |= POLLIN | POLLRDNORM;
 572         spin_unlock_irqrestore(&dst_q->done_lock, flags);
 573
 574 end:
 575         return rc;
 576 }
 577 EXPORT_SYMBOL_GPL(v4l2_m2m_poll);
 578
 579 /**
 580  * v4l2_m2m_mmap() - source and destination queues-aware mmap multiplexer
 581  *
 582  * Call from driver's mmap() function. Will handle mmap() for both queues
 583  * seamlessly for videobuffer, which will receive normal per-queue offsets and
 584  * proper videobuf queue pointers. The differentiation is made outside videobuf
 585  * by adding a predefined offset to buffers from one of the queues and
 586  * subtracting it before passing it back to videobuf. Only drivers (and
 587  * thus applications) receive modified offsets.
 588  */
 589 int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 590                          struct vm_area_struct *vma)
 591 {
 592         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 593         struct vb2_queue *vq;
 594
 595         if (offset < DST_QUEUE_OFF_BASE) {
 596                 vq = v4l2_m2m_get_src_vq(m2m_ctx);
 597         } else {
 598                 vq = v4l2_m2m_get_dst_vq(m2m_ctx);
 599                 vma->vm_pgoff -= (DST_QUEUE_OFF_BASE >> PAGE_SHIFT);
 600         }
 601
 602         return vb2_mmap(vq, vma);
 603 }
 604 EXPORT_SYMBOL(v4l2_m2m_mmap);
 605
 606 /**
 607  * v4l2_m2m_init() - initialize per-driver m2m data
 608  *
 609  * Usually called from driver's probe() function.
 610  */
 611 struct v4l2_m2m_dev *v4l2_m2m_init(const struct v4l2_m2m_ops *m2m_ops)
 612 {
 613         struct v4l2_m2m_dev *m2m_dev;
 614
 615         if (!m2m_ops || WARN_ON(!m2m_ops->device_run) ||
 616                         WARN_ON(!m2m_ops->job_abort))
 617                 return ERR_PTR(-EINVAL);
 618
 619         m2m_dev = kzalloc(sizeof *m2m_dev, GFP_KERNEL);
 620         if (!m2m_dev)
 621                 return ERR_PTR(-ENOMEM);
 622
 623         m2m_dev->curr_ctx = NULL;
 624         m2m_dev->m2m_ops = m2m_ops;
 625         INIT_LIST_HEAD(&m2m_dev->job_queue);
 626         spin_lock_init(&m2m_dev->job_spinlock);
 627
 628         return m2m_dev;
 629 }
 630 EXPORT_SYMBOL_GPL(v4l2_m2m_init);
 631
 632 /**
 633  * v4l2_m2m_release() - cleans up and frees a m2m_dev structure
 634  *
 635  * Usually called from driver's remove() function.
 636  */
 637 void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev)
 638 {
 639         kfree(m2m_dev);
 640 }
 641 EXPORT_SYMBOL_GPL(v4l2_m2m_release);
 642
 643 /**
 644  * v4l2_m2m_ctx_init() - allocate and initialize a m2m context
 645  * @priv - driver's instance private data
 646  * @m2m_dev - a previously initialized m2m_dev struct
 647  * @vq_init - a callback for queue type-specific initialization function to be
 648  * used for initializing videobuf_queues
 649  *
 650  * Usually called from driver's open() function.
 651  */
 652 struct v4l2_m2m_ctx *v4l2_m2m_ctx_init(struct v4l2_m2m_dev *m2m_dev,
 653                 void *drv_priv,
 654                 int (*queue_init)(void *priv, struct vb2_queue *src_vq, struct vb2_queue *dst_vq))
 655 {
 656         struct v4l2_m2m_ctx *m2m_ctx;
 657         struct v4l2_m2m_queue_ctx *out_q_ctx, *cap_q_ctx;
 658         int ret;
 659
 660         m2m_ctx = kzalloc(sizeof *m2m_ctx, GFP_KERNEL);
 661         if (!m2m_ctx)
 662                 return ERR_PTR(-ENOMEM);
 663
 664         m2m_ctx->priv = drv_priv;
 665         m2m_ctx->m2m_dev = m2m_dev;
 666         init_waitqueue_head(&m2m_ctx->finished);
 667
 668         out_q_ctx = &m2m_ctx->out_q_ctx;
 669         cap_q_ctx = &m2m_ctx->cap_q_ctx;
 670
 671         INIT_LIST_HEAD(&out_q_ctx->rdy_queue);
 672         INIT_LIST_HEAD(&cap_q_ctx->rdy_queue);
 673         spin_lock_init(&out_q_ctx->rdy_spinlock);
 674         spin_lock_init(&cap_q_ctx->rdy_spinlock);
 675
 676         INIT_LIST_HEAD(&m2m_ctx->queue);
 677
 678         ret = queue_init(drv_priv, &out_q_ctx->q, &cap_q_ctx->q);
 679
 680         if (ret)
 681                 goto err;
 682
 683         return m2m_ctx;
 684 err:
 685         kfree(m2m_ctx);
 686         return ERR_PTR(ret);
 687 }
 688 EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_init);
 689
 690 /**
 691  * v4l2_m2m_ctx_release() - release m2m context
 692  *
 693  * Usually called from driver's release() function.
 694  */
 695 void v4l2_m2m_ctx_release(struct v4l2_m2m_ctx *m2m_ctx)
 696 {
 697         /* wait until the current context is dequeued from job_queue */
 698         v4l2_m2m_cancel_job(m2m_ctx);
 699
 700         vb2_queue_release(&m2m_ctx->cap_q_ctx.q);
 701         vb2_queue_release(&m2m_ctx->out_q_ctx.q);
 702
 703         kfree(m2m_ctx);
 704 }
 705 EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_release);
 706
 707 /**
 708  * v4l2_m2m_buf_queue() - add a buffer to the proper ready buffers list.
 709  *
 710  * Call from buf_queue(), videobuf_queue_ops callback.
 711  */
 712 void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx, struct vb2_buffer *vb)
 713 {
 714         struct v4l2_m2m_buffer *b = container_of(vb, struct v4l2_m2m_buffer, vb);
 715         struct v4l2_m2m_queue_ctx *q_ctx;
 716         unsigned long flags;
 717
 718         q_ctx = get_queue_ctx(m2m_ctx, vb->vb2_queue->type);
 719         if (!q_ctx)
 720                 return;
 721
 722         spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
 723         list_add_tail(&b->list, &q_ctx->rdy_queue);
 724         q_ctx->num_rdy++;
 725         spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
 726 }
 727 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_queue);
 728