seq_fifo.h

 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
15struct 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) */
28struct snd_seq_fifo *snd_seq_fifo_new(int poolsize);
29
30/* delete fifo (destructor) */
31void snd_seq_fifo_delete(struct snd_seq_fifo **f);
32
33
34/* enqueue event to fifo */
35int 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)
40DEFINE_GUARD(snd_seq_fifo, struct snd_seq_fifo *, snd_seq_fifo_lock(_T), snd_seq_fifo_unlock(_T))
41
42/* get a cell from fifo - fifo should be locked */
43int snd_seq_fifo_cell_out(struct snd_seq_fifo *f, struct snd_seq_event_cell **cellp, int nonblock);
44
45/* free dequeued cell - fifo should be locked */
46void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f, struct snd_seq_event_cell *cell);
47
48/* clean up queue */
49void snd_seq_fifo_clear(struct snd_seq_fifo *f);
50
51/* polling */
52int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file, poll_table *wait);
53
54/* resize pool in fifo */
55int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize);
56
57/* get the number of unused cells safely */
58int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f);
59
60#endif