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 60