root/sound/core/seq/seq_fifo.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  *   ALSA sequencer FIFO
   4  *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
   5  */
   6 #ifndef __SND_SEQ_FIFO_H
   7 #define __SND_SEQ_FIFO_H
   8 
   9 #include "seq_memory.h"
  10 #include "seq_lock.h"
  11 
  12 
  13 /* === FIFO === */
  14 
  15 struct snd_seq_fifo {
  16         struct snd_seq_pool *pool;              /* FIFO pool */
  17         struct snd_seq_event_cell *head;        /* pointer to head of fifo */
  18         struct snd_seq_event_cell *tail;        /* pointer to tail of fifo */
  19         int cells;
  20         spinlock_t lock;
  21         snd_use_lock_t use_lock;
  22         wait_queue_head_t input_sleep;
  23         atomic_t overflow;
  24 
  25 };
  26 
  27 /* create new fifo (constructor) */
  28 struct snd_seq_fifo *snd_seq_fifo_new(int poolsize);
  29 
  30 /* delete fifo (destructor) */
  31 void snd_seq_fifo_delete(struct snd_seq_fifo **f);
  32 
  33 
  34 /* enqueue event to fifo */
  35 int snd_seq_fifo_event_in(struct snd_seq_fifo *f, struct snd_seq_event *event);
  36 
  37 /* lock fifo from release */
  38 #define snd_seq_fifo_lock(fifo)         snd_use_lock_use(&(fifo)->use_lock)
  39 #define snd_seq_fifo_unlock(fifo)       snd_use_lock_free(&(fifo)->use_lock)
  40 
  41 /* get a cell from fifo - fifo should be locked */
  42 int snd_seq_fifo_cell_out(struct snd_seq_fifo *f, struct snd_seq_event_cell **cellp, int nonblock);
  43 
  44 /* free dequeued cell - fifo should be locked */
  45 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f, struct snd_seq_event_cell *cell);
  46 
  47 /* clean up queue */
  48 void snd_seq_fifo_clear(struct snd_seq_fifo *f);
  49 
  50 /* polling */
  51 int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file, poll_table *wait);
  52 
  53 /* resize pool in fifo */
  54 int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize);
  55 
  56 /* get the number of unused cells safely */
  57 int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f);
  58 
  59 #endif