root/sound/core/seq/seq_timer.h

INCLUDED FROM

DEFINITIONS

1. snd_seq_timer_update_tick
2. snd_seq_compare_tick_time
3. snd_seq_compare_real_time
4. snd_seq_sanity_real_time
5. snd_seq_inc_real_time
6. snd_seq_inc_time_nsec

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  *  ALSA sequencer Timer
   4  *  Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
   5  */
   6 #ifndef __SND_SEQ_TIMER_H
   7 #define __SND_SEQ_TIMER_H
   8 
   9 #include <sound/timer.h>
  10 #include <sound/seq_kernel.h>
  11 
  12 struct snd_seq_timer_tick {
  13         snd_seq_tick_time_t     cur_tick;       /* current tick */
  14         unsigned long           resolution;     /* time per tick in nsec */
  15         unsigned long           fraction;       /* current time per tick in nsec */
  16 };
  17 
  18 struct snd_seq_timer {
  19         /* ... tempo / offset / running state */
  20 
  21         unsigned int            running:1,      /* running state of queue */    
  22                                 initialized:1;  /* timer is initialized */
  23 
  24         unsigned int            tempo;          /* current tempo, us/tick */
  25         int                     ppq;            /* time resolution, ticks/quarter */
  26 
  27         snd_seq_real_time_t     cur_time;       /* current time */
  28         struct snd_seq_timer_tick       tick;   /* current tick */
  29         int tick_updated;
  30         
  31         int                     type;           /* timer type */
  32         struct snd_timer_id     alsa_id;        /* ALSA's timer ID */
  33         struct snd_timer_instance       *timeri;        /* timer instance */
  34         unsigned int            ticks;
  35         unsigned long           preferred_resolution; /* timer resolution, ticks/sec */
  36 
  37         unsigned int skew;
  38         unsigned int skew_base;
  39 
  40         struct timespec64       last_update;     /* time of last clock update, used for interpolation */
  41 
  42         spinlock_t lock;
  43 };
  44 
  45 
  46 /* create new timer (constructor) */
  47 struct snd_seq_timer *snd_seq_timer_new(void);
  48 
  49 /* delete timer (destructor) */
  50 void snd_seq_timer_delete(struct snd_seq_timer **tmr);
  51 
  52 /* */
  53 static inline void snd_seq_timer_update_tick(struct snd_seq_timer_tick *tick,
  54                                              unsigned long resolution)
  55 {
  56         if (tick->resolution > 0) {
  57                 tick->fraction += resolution;
  58                 tick->cur_tick += (unsigned int)(tick->fraction / tick->resolution);
  59                 tick->fraction %= tick->resolution;
  60         }
  61 }
  62 
  63 
  64 /* compare timestamp between events */
  65 /* return 1 if a >= b; otherwise return 0 */
  66 static inline int snd_seq_compare_tick_time(snd_seq_tick_time_t *a, snd_seq_tick_time_t *b)
  67 {
  68         /* compare ticks */
  69         return (*a >= *b);
  70 }
  71 
  72 static inline int snd_seq_compare_real_time(snd_seq_real_time_t *a, snd_seq_real_time_t *b)
  73 {
  74         /* compare real time */
  75         if (a->tv_sec > b->tv_sec)
  76                 return 1;
  77         if ((a->tv_sec == b->tv_sec) && (a->tv_nsec >= b->tv_nsec))
  78                 return 1;
  79         return 0;
  80 }
  81 
  82 
  83 static inline void snd_seq_sanity_real_time(snd_seq_real_time_t *tm)
  84 {
  85         while (tm->tv_nsec >= 1000000000) {
  86                 /* roll-over */
  87                 tm->tv_nsec -= 1000000000;
  88                 tm->tv_sec++;
  89         }
  90 }
  91 
  92 
  93 /* increment timestamp */
  94 static inline void snd_seq_inc_real_time(snd_seq_real_time_t *tm, snd_seq_real_time_t *inc)
  95 {
  96         tm->tv_sec  += inc->tv_sec;
  97         tm->tv_nsec += inc->tv_nsec;
  98         snd_seq_sanity_real_time(tm);
  99 }
 100 
 101 static inline void snd_seq_inc_time_nsec(snd_seq_real_time_t *tm, unsigned long nsec)
 102 {
 103         tm->tv_nsec  += nsec;
 104         snd_seq_sanity_real_time(tm);
 105 }
 106 
 107 /* called by timer isr */
 108 struct snd_seq_queue;
 109 int snd_seq_timer_open(struct snd_seq_queue *q);
 110 int snd_seq_timer_close(struct snd_seq_queue *q);
 111 int snd_seq_timer_midi_open(struct snd_seq_queue *q);
 112 int snd_seq_timer_midi_close(struct snd_seq_queue *q);
 113 void snd_seq_timer_defaults(struct snd_seq_timer *tmr);
 114 void snd_seq_timer_reset(struct snd_seq_timer *tmr);
 115 int snd_seq_timer_stop(struct snd_seq_timer *tmr);
 116 int snd_seq_timer_start(struct snd_seq_timer *tmr);
 117 int snd_seq_timer_continue(struct snd_seq_timer *tmr);
 118 int snd_seq_timer_set_tempo(struct snd_seq_timer *tmr, int tempo);
 119 int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq);
 120 int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position);
 121 int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position);
 122 int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base);
 123 snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
 124                                                bool adjust_ktime);
 125 snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr);
 126 
 127 extern int seq_default_timer_class;
 128 extern int seq_default_timer_sclass;
 129 extern int seq_default_timer_card;
 130 extern int seq_default_timer_device;
 131 extern int seq_default_timer_subdevice;
 132 extern int seq_default_timer_resolution;
 133 
 134 #endif