text: /*
   *  ALSA sequencer Timer
   *  Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
   *
   *
   *   This program is free software; you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License as published by
   *   the Free Software Foundation; either version 2 of the License, or
   *   (at your option) any later version.
   *
   *   This program is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *   GNU General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License
   *   along with this program; if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */
  #ifndef __SND_SEQ_TIMER_H
  #define __SND_SEQ_TIMER_H
  
  #include <sound/timer.h>
  #include <sound/seq_kernel.h>
  
  struct snd_seq_timer_tick {
  	snd_seq_tick_time_t	cur_tick;	/* current tick */
  	unsigned long		resolution;	/* time per tick in nsec */
  	unsigned long		fraction;	/* current time per tick in nsec */
  };
  
  struct snd_seq_timer {
  	/* ... tempo / offset / running state */
  
  	unsigned int		running:1,	/* running state of queue */	
  				initialized:1;	/* timer is initialized */
  
  	unsigned int		tempo;		/* current tempo, us/tick */
  	int			ppq;		/* time resolution, ticks/quarter */
  
  	snd_seq_real_time_t	cur_time;	/* current time */
  	struct snd_seq_timer_tick	tick;	/* current tick */
  	int tick_updated;
  	
  	int			type;		/* timer type */
  	struct snd_timer_id	alsa_id;	/* ALSA's timer ID */
  	struct snd_timer_instance	*timeri;	/* timer instance */
  	unsigned int		ticks;
  	unsigned long		preferred_resolution; /* timer resolution, ticks/sec */
  
  	unsigned int skew;
  	unsigned int skew_base;
  
  	struct timespec64	last_update;	 /* time of last clock update, used for interpolation */
  
  	spinlock_t lock;
  };
  
  
  /* create new timer (constructor) */
  struct snd_seq_timer *snd_seq_timer_new(void);
  
  /* delete timer (destructor) */
  void snd_seq_timer_delete(struct snd_seq_timer **tmr);
  
  /* */
  static inline void snd_seq_timer_update_tick(struct snd_seq_timer_tick *tick,
  					     unsigned long resolution)
  {
  	if (tick->resolution > 0) {
  		tick->fraction += resolution;
  		tick->cur_tick += (unsigned int)(tick->fraction / tick->resolution);
  		tick->fraction %= tick->resolution;
  	}
  }
  
  
  /* compare timestamp between events */
  /* return 1 if a >= b; otherwise return 0 */
  static inline int snd_seq_compare_tick_time(snd_seq_tick_time_t *a, snd_seq_tick_time_t *b)
  {
  	/* compare ticks */
  	return (*a >= *b);
  }
  
  static inline int snd_seq_compare_real_time(snd_seq_real_time_t *a, snd_seq_real_time_t *b)
  {
  	/* compare real time */
  	if (a->tv_sec > b->tv_sec)
  		return 1;
  	if ((a->tv_sec == b->tv_sec) && (a->tv_nsec >= b->tv_nsec))
  		return 1;
  	return 0;
  }
  
  
  static inline void snd_seq_sanity_real_time(snd_seq_real_time_t *tm)
  {
  	while (tm->tv_nsec >= 1000000000) {
  		/* roll-over */
  		tm->tv_nsec -= 1000000000;
                  tm->tv_sec++;
          }
  }
  
  
  /* increment timestamp */
  static inline void snd_seq_inc_real_time(snd_seq_real_time_t *tm, snd_seq_real_time_t *inc)
  {
  	tm->tv_sec  += inc->tv_sec;
  	tm->tv_nsec += inc->tv_nsec;
  	snd_seq_sanity_real_time(tm);
  }
  
  static inline void snd_seq_inc_time_nsec(snd_seq_real_time_t *tm, unsigned long nsec)
  {
  	tm->tv_nsec  += nsec;
  	snd_seq_sanity_real_time(tm);
  }
  
  /* called by timer isr */
  struct snd_seq_queue;
  int snd_seq_timer_open(struct snd_seq_queue *q);
  int snd_seq_timer_close(struct snd_seq_queue *q);
  int snd_seq_timer_midi_open(struct snd_seq_queue *q);
  int snd_seq_timer_midi_close(struct snd_seq_queue *q);
  void snd_seq_timer_defaults(struct snd_seq_timer *tmr);
  void snd_seq_timer_reset(struct snd_seq_timer *tmr);
  int snd_seq_timer_stop(struct snd_seq_timer *tmr);
  int snd_seq_timer_start(struct snd_seq_timer *tmr);
  int snd_seq_timer_continue(struct snd_seq_timer *tmr);
  int snd_seq_timer_set_tempo(struct snd_seq_timer *tmr, int tempo);
  int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq);
  int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position);
  int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position);
  int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base);
  snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
  					       bool adjust_ktime);
  snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr);
  
  extern int seq_default_timer_class;
  extern int seq_default_timer_sclass;
  extern int seq_default_timer_card;
  extern int seq_default_timer_device;
  extern int seq_default_timer_subdevice;
  extern int seq_default_timer_resolution;
  
  #endif
  