mirror of https://gitee.com/openkylin/linux.git
60 lines
1.7 KiB
C
60 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* ALSA sequencer FIFO
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* Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
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*/
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#ifndef __SND_SEQ_FIFO_H
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#define __SND_SEQ_FIFO_H
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#include "seq_memory.h"
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#include "seq_lock.h"
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/* === FIFO === */
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struct snd_seq_fifo {
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struct snd_seq_pool *pool; /* FIFO pool */
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struct snd_seq_event_cell *head; /* pointer to head of fifo */
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struct snd_seq_event_cell *tail; /* pointer to tail of fifo */
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int cells;
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spinlock_t lock;
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snd_use_lock_t use_lock;
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wait_queue_head_t input_sleep;
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atomic_t overflow;
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};
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/* create new fifo (constructor) */
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struct snd_seq_fifo *snd_seq_fifo_new(int poolsize);
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/* delete fifo (destructor) */
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void snd_seq_fifo_delete(struct snd_seq_fifo **f);
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/* enqueue event to fifo */
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int snd_seq_fifo_event_in(struct snd_seq_fifo *f, struct snd_seq_event *event);
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/* lock fifo from release */
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#define snd_seq_fifo_lock(fifo) snd_use_lock_use(&(fifo)->use_lock)
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#define snd_seq_fifo_unlock(fifo) snd_use_lock_free(&(fifo)->use_lock)
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/* get a cell from fifo - fifo should be locked */
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int snd_seq_fifo_cell_out(struct snd_seq_fifo *f, struct snd_seq_event_cell **cellp, int nonblock);
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/* free dequeued cell - fifo should be locked */
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void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f, struct snd_seq_event_cell *cell);
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/* clean up queue */
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void snd_seq_fifo_clear(struct snd_seq_fifo *f);
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/* polling */
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int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file, poll_table *wait);
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/* resize pool in fifo */
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int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize);
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/* get the number of unused cells safely */
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int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f);
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#endif
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