sound/core/seq/seq_fifo.h

   1 /*
   2  *   ALSA sequencer FIFO
   3  *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21 #ifndef __SND_SEQ_FIFO_H
  22 #define __SND_SEQ_FIFO_H
  23
  24 #include "seq_memory.h"
  25 #include "seq_lock.h"
  26
  27
  28 /* === FIFO === */
  29
  30 typedef struct {
  31         pool_t *pool;                   /* FIFO pool */
  32         snd_seq_event_cell_t* head;     /* pointer to head of fifo */
  33         snd_seq_event_cell_t* tail;     /* pointer to tail of fifo */
  34         int cells;
  35         spinlock_t lock;
  36         snd_use_lock_t use_lock;
  37         wait_queue_head_t input_sleep;
  38         atomic_t overflow;
  39
  40 } fifo_t;
  41
  42 /* create new fifo (constructor) */
  43 extern fifo_t *snd_seq_fifo_new(int poolsize);
  44
  45 /* delete fifo (destructor) */
  46 extern void snd_seq_fifo_delete(fifo_t **f);
  47
  48
  49 /* enqueue event to fifo */
  50 extern int snd_seq_fifo_event_in(fifo_t *f, snd_seq_event_t *event);
  51
  52 /* lock fifo from release */
  53 #define snd_seq_fifo_lock(fifo)         snd_use_lock_use(&(fifo)->use_lock)
  54 #define snd_seq_fifo_unlock(fifo)       snd_use_lock_free(&(fifo)->use_lock)
  55
  56 /* get a cell from fifo - fifo should be locked */
  57 int snd_seq_fifo_cell_out(fifo_t *f, snd_seq_event_cell_t **cellp, int nonblock);
  58
  59 /* free dequeued cell - fifo should be locked */
  60 extern void snd_seq_fifo_cell_putback(fifo_t *f, snd_seq_event_cell_t *cell);
  61
  62 /* clean up queue */
  63 extern void snd_seq_fifo_clear(fifo_t *f);
  64
  65 /* polling */
  66 extern int snd_seq_fifo_poll_wait(fifo_t *f, struct file *file, poll_table *wait);
  67
  68 /* resize pool in fifo */
  69 int snd_seq_fifo_resize(fifo_t *f, int poolsize);
  70
  71
  72 #endif