include/media/v4l2-mem2mem.h

   1 /*
   2  * Memory-to-memory device framework for Video for Linux 2.
   3  *
   4  * Helper functions for devices that use memory buffers for both source
   5  * and destination.
   6  *
   7  * Copyright (c) 2009 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
  14  * License, or (at your option) any later version
  15  */
  16
  17 #ifndef _MEDIA_V4L2_MEM2MEM_H
  18 #define _MEDIA_V4L2_MEM2MEM_H
  19
  20 #include <media/videobuf2-v4l2.h>
  21
  22 /**
  23  * struct v4l2_m2m_ops - mem-to-mem device driver callbacks
  24  * @device_run: required. Begin the actual job (transaction) inside this
  25  *              callback.
  26  *              The job does NOT have to end before this callback returns
  27  *              (and it will be the usual case). When the job finishes,
  28  *              v4l2_m2m_job_finish() has to be called.
  29  * @job_ready:  optional. Should return 0 if the driver does not have a job
  30  *              fully prepared to run yet (i.e. it will not be able to finish a
  31  *              transaction without sleeping). If not provided, it will be
  32  *              assumed that one source and one destination buffer are all
  33  *              that is required for the driver to perform one full transaction.
  34  *              This method may not sleep.
  35  * @job_abort:  required. Informs the driver that it has to abort the currently
  36  *              running transaction as soon as possible (i.e. as soon as it can
  37  *              stop the device safely; e.g. in the next interrupt handler),
  38  *              even if the transaction would not have been finished by then.
  39  *              After the driver performs the necessary steps, it has to call
  40  *              v4l2_m2m_job_finish() (as if the transaction ended normally).
  41  *              This function does not have to (and will usually not) wait
  42  *              until the device enters a state when it can be stopped.
  43  * @lock:       optional. Define a driver's own lock callback, instead of using
  44  *              &v4l2_m2m_ctx->q_lock.
  45  * @unlock:     optional. Define a driver's own unlock callback, instead of
  46  *              using &v4l2_m2m_ctx->q_lock.
  47  */
  48 struct v4l2_m2m_ops {
  49         void (*device_run)(void *priv);
  50         int (*job_ready)(void *priv);
  51         void (*job_abort)(void *priv);
  52         void (*lock)(void *priv);
  53         void (*unlock)(void *priv);
  54 };
  55
  56 struct v4l2_m2m_dev;
  57
  58 /**
  59  * struct v4l2_m2m_queue_ctx - represents a queue for buffers ready to be
  60  *      processed
  61  *
  62  * @q:          pointer to struct &vb2_queue
  63  * @rdy_queue:  List of V4L2 mem-to-mem queues
  64  * @rdy_spinlock: spin lock to protect the struct usage
  65  * @num_rdy:    number of buffers ready to be processed
  66  * @buffered:   is the queue buffered?
  67  *
  68  * Queue for buffers ready to be processed as soon as this
  69  * instance receives access to the device.
  70  */
  71
  72 struct v4l2_m2m_queue_ctx {
  73         struct vb2_queue        q;
  74
  75         struct list_head        rdy_queue;
  76         spinlock_t              rdy_spinlock;
  77         u8                      num_rdy;
  78         bool                    buffered;
  79 };
  80
  81 /**
  82  * struct v4l2_m2m_ctx - Memory to memory context structure
  83  *
  84  * @q_lock: struct &mutex lock
  85  * @m2m_dev: opaque pointer to the internal data to handle M2M context
  86  * @cap_q_ctx: Capture (output to memory) queue context
  87  * @out_q_ctx: Output (input from memory) queue context
  88  * @queue: List of memory to memory contexts
  89  * @job_flags: Job queue flags, used internally by v4l2-mem2mem.c:
  90  *              %TRANS_QUEUED, %TRANS_RUNNING and %TRANS_ABORT.
  91  * @finished: Wait queue used to signalize when a job queue finished.
  92  * @priv: Instance private data
  93  *
  94  * The memory to memory context is specific to a file handle, NOT to e.g.
  95  * a device.
  96  */
  97 struct v4l2_m2m_ctx {
  98         /* optional cap/out vb2 queues lock */
  99         struct mutex                    *q_lock;
 100
 101         /* internal use only */
 102         struct v4l2_m2m_dev             *m2m_dev;
 103
 104         struct v4l2_m2m_queue_ctx       cap_q_ctx;
 105
 106         struct v4l2_m2m_queue_ctx       out_q_ctx;
 107
 108         /* For device job queue */
 109         struct list_head                queue;
 110         unsigned long                   job_flags;
 111         wait_queue_head_t               finished;
 112
 113         void                            *priv;
 114 };
 115
 116 /**
 117  * struct v4l2_m2m_buffer - Memory to memory buffer
 118  *
 119  * @vb: pointer to struct &vb2_v4l2_buffer
 120  * @list: list of m2m buffers
 121  */
 122 struct v4l2_m2m_buffer {
 123         struct vb2_v4l2_buffer  vb;
 124         struct list_head        list;
 125 };
 126
 127 /**
 128  * v4l2_m2m_get_curr_priv() - return driver private data for the currently
 129  * running instance or NULL if no instance is running
 130  *
 131  * @m2m_dev: opaque pointer to the internal data to handle M2M context
 132  */
 133 void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev);
 134
 135 /**
 136  * v4l2_m2m_get_vq() - return vb2_queue for the given type
 137  *
 138  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 139  * @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
 140  */
 141 struct vb2_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
 142                                        enum v4l2_buf_type type);
 143
 144 /**
 145  * v4l2_m2m_try_schedule() - check whether an instance is ready to be added to
 146  * the pending job queue and add it if so.
 147  *
 148  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 149  *
 150  * There are three basic requirements an instance has to meet to be able to run:
 151  * 1) at least one source buffer has to be queued,
 152  * 2) at least one destination buffer has to be queued,
 153  * 3) streaming has to be on.
 154  *
 155  * If a queue is buffered (for example a decoder hardware ringbuffer that has
 156  * to be drained before doing streamoff), allow scheduling without v4l2 buffers
 157  * on that queue.
 158  *
 159  * There may also be additional, custom requirements. In such case the driver
 160  * should supply a custom callback (job_ready in v4l2_m2m_ops) that should
 161  * return 1 if the instance is ready.
 162  * An example of the above could be an instance that requires more than one
 163  * src/dst buffer per transaction.
 164  */
 165 void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx);
 166
 167 /**
 168  * v4l2_m2m_job_finish() - inform the framework that a job has been finished
 169  * and have it clean up
 170  *
 171  * @m2m_dev: opaque pointer to the internal data to handle M2M context
 172  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 173  *
 174  * Called by a driver to yield back the device after it has finished with it.
 175  * Should be called as soon as possible after reaching a state which allows
 176  * other instances to take control of the device.
 177  *
 178  * This function has to be called only after &v4l2_m2m_ops->device_run
 179  * callback has been called on the driver. To prevent recursion, it should
 180  * not be called directly from the &v4l2_m2m_ops->device_run callback though.
 181  */
 182 void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
 183                          struct v4l2_m2m_ctx *m2m_ctx);
 184
 185 static inline void
 186 v4l2_m2m_buf_done(struct vb2_v4l2_buffer *buf, enum vb2_buffer_state state)
 187 {
 188         vb2_buffer_done(&buf->vb2_buf, state);
 189 }
 190
 191 /**
 192  * v4l2_m2m_reqbufs() - multi-queue-aware REQBUFS multiplexer
 193  *
 194  * @file: pointer to struct &file
 195  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 196  * @reqbufs: pointer to struct &v4l2_requestbuffers
 197  */
 198 int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 199                      struct v4l2_requestbuffers *reqbufs);
 200
 201 /**
 202  * v4l2_m2m_querybuf() - multi-queue-aware QUERYBUF multiplexer
 203  *
 204  * @file: pointer to struct &file
 205  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 206  * @buf: pointer to struct &v4l2_buffer
 207  *
 208  * See v4l2_m2m_mmap() documentation for details.
 209  */
 210 int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 211                       struct v4l2_buffer *buf);
 212
 213 /**
 214  * v4l2_m2m_qbuf() - enqueue a source or destination buffer, depending on
 215  * the type
 216  *
 217  * @file: pointer to struct &file
 218  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 219  * @buf: pointer to struct &v4l2_buffer
 220  */
 221 int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 222                   struct v4l2_buffer *buf);
 223
 224 /**
 225  * v4l2_m2m_dqbuf() - dequeue a source or destination buffer, depending on
 226  * the type
 227  *
 228  * @file: pointer to struct &file
 229  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 230  * @buf: pointer to struct &v4l2_buffer
 231  */
 232 int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 233                    struct v4l2_buffer *buf);
 234
 235 /**
 236  * v4l2_m2m_prepare_buf() - prepare a source or destination buffer, depending on
 237  * the type
 238  *
 239  * @file: pointer to struct &file
 240  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 241  * @buf: pointer to struct &v4l2_buffer
 242  */
 243 int v4l2_m2m_prepare_buf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 244                          struct v4l2_buffer *buf);
 245
 246 /**
 247  * v4l2_m2m_create_bufs() - create a source or destination buffer, depending
 248  * on the type
 249  *
 250  * @file: pointer to struct &file
 251  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 252  * @create: pointer to struct &v4l2_create_buffers
 253  */
 254 int v4l2_m2m_create_bufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 255                          struct v4l2_create_buffers *create);
 256
 257 /**
 258  * v4l2_m2m_expbuf() - export a source or destination buffer, depending on
 259  * the type
 260  *
 261  * @file: pointer to struct &file
 262  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 263  * @eb: pointer to struct &v4l2_exportbuffer
 264  */
 265 int v4l2_m2m_expbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 266                    struct v4l2_exportbuffer *eb);
 267
 268 /**
 269  * v4l2_m2m_streamon() - turn on streaming for a video queue
 270  *
 271  * @file: pointer to struct &file
 272  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 273  * @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
 274  */
 275 int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 276                       enum v4l2_buf_type type);
 277
 278 /**
 279  * v4l2_m2m_streamoff() - turn off streaming for a video queue
 280  *
 281  * @file: pointer to struct &file
 282  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 283  * @type: type of the V4L2 buffer, as defined by enum &v4l2_buf_type
 284  */
 285 int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 286                        enum v4l2_buf_type type);
 287
 288 /**
 289  * v4l2_m2m_poll() - poll replacement, for destination buffers only
 290  *
 291  * @file: pointer to struct &file
 292  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 293  * @wait: pointer to struct &poll_table_struct
 294  *
 295  * Call from the driver's poll() function. Will poll both queues. If a buffer
 296  * is available to dequeue (with dqbuf) from the source queue, this will
 297  * indicate that a non-blocking write can be performed, while read will be
 298  * returned in case of the destination queue.
 299  */
 300 unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 301                            struct poll_table_struct *wait);
 302
 303 /**
 304  * v4l2_m2m_mmap() - source and destination queues-aware mmap multiplexer
 305  *
 306  * @file: pointer to struct &file
 307  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 308  * @vma: pointer to struct &vm_area_struct
 309  *
 310  * Call from driver's mmap() function. Will handle mmap() for both queues
 311  * seamlessly for videobuffer, which will receive normal per-queue offsets and
 312  * proper videobuf queue pointers. The differentiation is made outside videobuf
 313  * by adding a predefined offset to buffers from one of the queues and
 314  * subtracting it before passing it back to videobuf. Only drivers (and
 315  * thus applications) receive modified offsets.
 316  */
 317 int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 318                   struct vm_area_struct *vma);
 319
 320 /**
 321  * v4l2_m2m_init() - initialize per-driver m2m data
 322  *
 323  * @m2m_ops: pointer to struct v4l2_m2m_ops
 324  *
 325  * Usually called from driver's ``probe()`` function.
 326  *
 327  * Return: returns an opaque pointer to the internal data to handle M2M context
 328  */
 329 struct v4l2_m2m_dev *v4l2_m2m_init(const struct v4l2_m2m_ops *m2m_ops);
 330
 331 /**
 332  * v4l2_m2m_release() - cleans up and frees a m2m_dev structure
 333  *
 334  * @m2m_dev: opaque pointer to the internal data to handle M2M context
 335  *
 336  * Usually called from driver's ``remove()`` function.
 337  */
 338 void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev);
 339
 340 /**
 341  * v4l2_m2m_ctx_init() - allocate and initialize a m2m context
 342  *
 343  * @m2m_dev: opaque pointer to the internal data to handle M2M context
 344  * @drv_priv: driver's instance private data
 345  * @queue_init: a callback for queue type-specific initialization function
 346  *      to be used for initializing videobuf_queues
 347  *
 348  * Usually called from driver's ``open()`` function.
 349  */
 350 struct v4l2_m2m_ctx *v4l2_m2m_ctx_init(struct v4l2_m2m_dev *m2m_dev,
 351                 void *drv_priv,
 352                 int (*queue_init)(void *priv, struct vb2_queue *src_vq, struct vb2_queue *dst_vq));
 353
 354 static inline void v4l2_m2m_set_src_buffered(struct v4l2_m2m_ctx *m2m_ctx,
 355                                              bool buffered)
 356 {
 357         m2m_ctx->out_q_ctx.buffered = buffered;
 358 }
 359
 360 static inline void v4l2_m2m_set_dst_buffered(struct v4l2_m2m_ctx *m2m_ctx,
 361                                              bool buffered)
 362 {
 363         m2m_ctx->cap_q_ctx.buffered = buffered;
 364 }
 365
 366 /**
 367  * v4l2_m2m_ctx_release() - release m2m context
 368  *
 369  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 370  *
 371  * Usually called from driver's release() function.
 372  */
 373 void v4l2_m2m_ctx_release(struct v4l2_m2m_ctx *m2m_ctx);
 374
 375 /**
 376  * v4l2_m2m_buf_queue() - add a buffer to the proper ready buffers list.
 377  *
 378  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 379  * @vbuf: pointer to struct &vb2_v4l2_buffer
 380  *
 381  * Call from videobuf_queue_ops->ops->buf_queue, videobuf_queue_ops callback.
 382  */
 383 void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx,
 384                         struct vb2_v4l2_buffer *vbuf);
 385
 386 /**
 387  * v4l2_m2m_num_src_bufs_ready() - return the number of source buffers ready for
 388  * use
 389  *
 390  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 391  */
 392 static inline
 393 unsigned int v4l2_m2m_num_src_bufs_ready(struct v4l2_m2m_ctx *m2m_ctx)
 394 {
 395         return m2m_ctx->out_q_ctx.num_rdy;
 396 }
 397
 398 /**
 399  * v4l2_m2m_num_dst_bufs_ready() - return the number of destination buffers
 400  * ready for use
 401  *
 402  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 403  */
 404 static inline
 405 unsigned int v4l2_m2m_num_dst_bufs_ready(struct v4l2_m2m_ctx *m2m_ctx)
 406 {
 407         return m2m_ctx->cap_q_ctx.num_rdy;
 408 }
 409
 410 /**
 411  * v4l2_m2m_next_buf() - return next buffer from the list of ready buffers
 412  *
 413  * @q_ctx: pointer to struct @v4l2_m2m_queue_ctx
 414  */
 415 void *v4l2_m2m_next_buf(struct v4l2_m2m_queue_ctx *q_ctx);
 416
 417 /**
 418  * v4l2_m2m_next_src_buf() - return next source buffer from the list of ready
 419  * buffers
 420  *
 421  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 422  */
 423 static inline void *v4l2_m2m_next_src_buf(struct v4l2_m2m_ctx *m2m_ctx)
 424 {
 425         return v4l2_m2m_next_buf(&m2m_ctx->out_q_ctx);
 426 }
 427
 428 /**
 429  * v4l2_m2m_next_dst_buf() - return next destination buffer from the list of
 430  * ready buffers
 431  *
 432  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 433  */
 434 static inline void *v4l2_m2m_next_dst_buf(struct v4l2_m2m_ctx *m2m_ctx)
 435 {
 436         return v4l2_m2m_next_buf(&m2m_ctx->cap_q_ctx);
 437 }
 438
 439 /**
 440  * v4l2_m2m_get_src_vq() - return vb2_queue for source buffers
 441  *
 442  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 443  */
 444 static inline
 445 struct vb2_queue *v4l2_m2m_get_src_vq(struct v4l2_m2m_ctx *m2m_ctx)
 446 {
 447         return &m2m_ctx->out_q_ctx.q;
 448 }
 449
 450 /**
 451  * v4l2_m2m_get_dst_vq() - return vb2_queue for destination buffers
 452  *
 453  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 454  */
 455 static inline
 456 struct vb2_queue *v4l2_m2m_get_dst_vq(struct v4l2_m2m_ctx *m2m_ctx)
 457 {
 458         return &m2m_ctx->cap_q_ctx.q;
 459 }
 460
 461 /**
 462  * v4l2_m2m_buf_remove() - take off a buffer from the list of ready buffers and
 463  * return it
 464  *
 465  * @q_ctx: pointer to struct @v4l2_m2m_queue_ctx
 466  */
 467 void *v4l2_m2m_buf_remove(struct v4l2_m2m_queue_ctx *q_ctx);
 468
 469 /**
 470  * v4l2_m2m_src_buf_remove() - take off a source buffer from the list of ready
 471  * buffers and return it
 472  *
 473  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 474  */
 475 static inline void *v4l2_m2m_src_buf_remove(struct v4l2_m2m_ctx *m2m_ctx)
 476 {
 477         return v4l2_m2m_buf_remove(&m2m_ctx->out_q_ctx);
 478 }
 479
 480 /**
 481  * v4l2_m2m_dst_buf_remove() - take off a destination buffer from the list of
 482  * ready buffers and return it
 483  *
 484  * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
 485  */
 486 static inline void *v4l2_m2m_dst_buf_remove(struct v4l2_m2m_ctx *m2m_ctx)
 487 {
 488         return v4l2_m2m_buf_remove(&m2m_ctx->cap_q_ctx);
 489 }
 490
 491 /* v4l2 ioctl helpers */
 492
 493 int v4l2_m2m_ioctl_reqbufs(struct file *file, void *priv,
 494                                 struct v4l2_requestbuffers *rb);
 495 int v4l2_m2m_ioctl_create_bufs(struct file *file, void *fh,
 496                                 struct v4l2_create_buffers *create);
 497 int v4l2_m2m_ioctl_querybuf(struct file *file, void *fh,
 498                                 struct v4l2_buffer *buf);
 499 int v4l2_m2m_ioctl_expbuf(struct file *file, void *fh,
 500                                 struct v4l2_exportbuffer *eb);
 501 int v4l2_m2m_ioctl_qbuf(struct file *file, void *fh,
 502                                 struct v4l2_buffer *buf);
 503 int v4l2_m2m_ioctl_dqbuf(struct file *file, void *fh,
 504                                 struct v4l2_buffer *buf);
 505 int v4l2_m2m_ioctl_prepare_buf(struct file *file, void *fh,
 506                                struct v4l2_buffer *buf);
 507 int v4l2_m2m_ioctl_streamon(struct file *file, void *fh,
 508                                 enum v4l2_buf_type type);
 509 int v4l2_m2m_ioctl_streamoff(struct file *file, void *fh,
 510                                 enum v4l2_buf_type type);
 511 int v4l2_m2m_fop_mmap(struct file *file, struct vm_area_struct *vma);
 512 unsigned int v4l2_m2m_fop_poll(struct file *file, poll_table *wait);
 513
 514 #endif /* _MEDIA_V4L2_MEM2MEM_H */
 515