Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
seq_timer.h
Go to the documentation of this file.
1 /*
2  * ALSA sequencer Timer
3  * Copyright (c) 1998-1999 by Frank van de Pol <[email protected]>
4  *
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19  *
20  */
21 #ifndef __SND_SEQ_TIMER_H
22 #define __SND_SEQ_TIMER_H
23 
24 #include <sound/timer.h>
25 #include <sound/seq_kernel.h>
26 
27 struct snd_seq_timer_tick {
28  snd_seq_tick_time_t cur_tick; /* current tick */
29  unsigned long resolution; /* time per tick in nsec */
30  unsigned long fraction; /* current time per tick in nsec */
31 };
32 
33 struct snd_seq_timer {
34  /* ... tempo / offset / running state */
35 
36  unsigned int running:1, /* running state of queue */
37  initialized:1; /* timer is initialized */
38 
39  unsigned int tempo; /* current tempo, us/tick */
40  int ppq; /* time resolution, ticks/quarter */
41 
42  snd_seq_real_time_t cur_time; /* current time */
43  struct snd_seq_timer_tick tick; /* current tick */
44  int tick_updated;
45 
46  int type; /* timer type */
47  struct snd_timer_id alsa_id; /* ALSA's timer ID */
48  struct snd_timer_instance *timeri; /* timer instance */
49  unsigned int ticks;
50  unsigned long preferred_resolution; /* timer resolution, ticks/sec */
51 
52  unsigned int skew;
53  unsigned int skew_base;
54 
55  struct timeval last_update; /* time of last clock update, used for interpolation */
56 
57  spinlock_t lock;
58 };
59 
60 
61 /* create new timer (constructor) */
62 struct snd_seq_timer *snd_seq_timer_new(void);
63 
64 /* delete timer (destructor) */
65 void snd_seq_timer_delete(struct snd_seq_timer **tmr);
66 
67 /* */
68 static inline void snd_seq_timer_update_tick(struct snd_seq_timer_tick *tick,
69  unsigned long resolution)
70 {
71  if (tick->resolution > 0) {
72  tick->fraction += resolution;
73  tick->cur_tick += (unsigned int)(tick->fraction / tick->resolution);
74  tick->fraction %= tick->resolution;
75  }
76 }
77 
78 
79 /* compare timestamp between events */
80 /* return 1 if a >= b; otherwise return 0 */
81 static inline int snd_seq_compare_tick_time(snd_seq_tick_time_t *a, snd_seq_tick_time_t *b)
82 {
83  /* compare ticks */
84  return (*a >= *b);
85 }
86 
87 static inline int snd_seq_compare_real_time(snd_seq_real_time_t *a, snd_seq_real_time_t *b)
88 {
89  /* compare real time */
90  if (a->tv_sec > b->tv_sec)
91  return 1;
92  if ((a->tv_sec == b->tv_sec) && (a->tv_nsec >= b->tv_nsec))
93  return 1;
94  return 0;
95 }
96 
97 
98 static inline void snd_seq_sanity_real_time(snd_seq_real_time_t *tm)
99 {
100  while (tm->tv_nsec >= 1000000000) {
101  /* roll-over */
102  tm->tv_nsec -= 1000000000;
103  tm->tv_sec++;
104  }
105 }
106 
107 
108 /* increment timestamp */
109 static inline void snd_seq_inc_real_time(snd_seq_real_time_t *tm, snd_seq_real_time_t *inc)
110 {
111  tm->tv_sec += inc->tv_sec;
112  tm->tv_nsec += inc->tv_nsec;
113  snd_seq_sanity_real_time(tm);
114 }
115 
116 static inline void snd_seq_inc_time_nsec(snd_seq_real_time_t *tm, unsigned long nsec)
117 {
118  tm->tv_nsec += nsec;
119  snd_seq_sanity_real_time(tm);
120 }
121 
122 /* called by timer isr */
123 struct snd_seq_queue;
124 int snd_seq_timer_open(struct snd_seq_queue *q);
125 int snd_seq_timer_close(struct snd_seq_queue *q);
126 int snd_seq_timer_midi_open(struct snd_seq_queue *q);
127 int snd_seq_timer_midi_close(struct snd_seq_queue *q);
128 void snd_seq_timer_defaults(struct snd_seq_timer *tmr);
129 void snd_seq_timer_reset(struct snd_seq_timer *tmr);
130 int snd_seq_timer_stop(struct snd_seq_timer *tmr);
131 int snd_seq_timer_start(struct snd_seq_timer *tmr);
132 int snd_seq_timer_continue(struct snd_seq_timer *tmr);
133 int snd_seq_timer_set_tempo(struct snd_seq_timer *tmr, int tempo);
134 int snd_seq_timer_set_ppq(struct snd_seq_timer *tmr, int ppq);
135 int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position);
136 int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position);
137 int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base);
138 snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr);
139 snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr);
140 
141 extern int seq_default_timer_class;
142 extern int seq_default_timer_sclass;
143 extern int seq_default_timer_card;
144 extern int seq_default_timer_device;
145 extern int seq_default_timer_subdevice;
146 extern int seq_default_timer_resolution;
147 
148 #endif
Generated on Thu Jan 10 2013 15:04:07 for Linux Kernel by   doxygen 1.8.2