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 * Jaroslav Kysela <perex@perex.cz>
6 */
7
8 #include <sound/core.h>
9 #include <linux/slab.h>
10 #include "seq_timer.h"
11 #include "seq_queue.h"
12 #include "seq_info.h"
13
14 /* allowed sequencer timer frequencies, in Hz */
15 #define MIN_FREQUENCY 10
16 #define MAX_FREQUENCY 6250
17 #define DEFAULT_FREQUENCY 1000
18
19 #define SKEW_BASE 0x10000 /* 16bit shift */
20
snd_seq_timer_set_tick_resolution(struct snd_seq_timer * tmr)21 static void snd_seq_timer_set_tick_resolution(struct snd_seq_timer *tmr)
22 {
23 if (tmr->tempo < 1000000)
24 tmr->tick.resolution = (tmr->tempo * 1000) / tmr->ppq;
25 else {
26 /* might overflow.. */
27 unsigned int s;
28 s = tmr->tempo % tmr->ppq;
29 s = (s * 1000) / tmr->ppq;
30 tmr->tick.resolution = (tmr->tempo / tmr->ppq) * 1000;
31 tmr->tick.resolution += s;
32 }
33 if (tmr->tick.resolution <= 0)
34 tmr->tick.resolution = 1;
35 snd_seq_timer_update_tick(&tmr->tick, 0);
36 }
37
38 /* create new timer (constructor) */
snd_seq_timer_new(void)39 struct snd_seq_timer *snd_seq_timer_new(void)
40 {
41 struct snd_seq_timer *tmr;
42
43 tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
44 if (!tmr)
45 return NULL;
46 spin_lock_init(&tmr->lock);
47
48 /* reset setup to defaults */
49 snd_seq_timer_defaults(tmr);
50
51 /* reset time */
52 snd_seq_timer_reset(tmr);
53
54 return tmr;
55 }
56
57 /* delete timer (destructor) */
snd_seq_timer_delete(struct snd_seq_timer ** tmr)58 void snd_seq_timer_delete(struct snd_seq_timer **tmr)
59 {
60 struct snd_seq_timer *t = *tmr;
61 *tmr = NULL;
62
63 if (t == NULL) {
64 pr_debug("ALSA: seq: snd_seq_timer_delete() called with NULL timer\n");
65 return;
66 }
67 t->running = 0;
68
69 /* reset time */
70 snd_seq_timer_stop(t);
71 snd_seq_timer_reset(t);
72
73 kfree(t);
74 }
75
snd_seq_timer_defaults(struct snd_seq_timer * tmr)76 void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
77 {
78 unsigned long flags;
79
80 spin_lock_irqsave(&tmr->lock, flags);
81 /* setup defaults */
82 tmr->ppq = 96; /* 96 PPQ */
83 tmr->tempo = 500000; /* 120 BPM */
84 snd_seq_timer_set_tick_resolution(tmr);
85 tmr->running = 0;
86
87 tmr->type = SNDRV_SEQ_TIMER_ALSA;
88 tmr->alsa_id.dev_class = seq_default_timer_class;
89 tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
90 tmr->alsa_id.card = seq_default_timer_card;
91 tmr->alsa_id.device = seq_default_timer_device;
92 tmr->alsa_id.subdevice = seq_default_timer_subdevice;
93 tmr->preferred_resolution = seq_default_timer_resolution;
94
95 tmr->skew = tmr->skew_base = SKEW_BASE;
96 spin_unlock_irqrestore(&tmr->lock, flags);
97 }
98
seq_timer_reset(struct snd_seq_timer * tmr)99 static void seq_timer_reset(struct snd_seq_timer *tmr)
100 {
101 /* reset time & songposition */
102 tmr->cur_time.tv_sec = 0;
103 tmr->cur_time.tv_nsec = 0;
104
105 tmr->tick.cur_tick = 0;
106 tmr->tick.fraction = 0;
107 }
108
snd_seq_timer_reset(struct snd_seq_timer * tmr)109 void snd_seq_timer_reset(struct snd_seq_timer *tmr)
110 {
111 unsigned long flags;
112
113 spin_lock_irqsave(&tmr->lock, flags);
114 seq_timer_reset(tmr);
115 spin_unlock_irqrestore(&tmr->lock, flags);
116 }
117
118
119 /* called by timer interrupt routine. the period time since previous invocation is passed */
snd_seq_timer_interrupt(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)120 static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
121 unsigned long resolution,
122 unsigned long ticks)
123 {
124 unsigned long flags;
125 struct snd_seq_queue *q = timeri->callback_data;
126 struct snd_seq_timer *tmr;
127
128 if (q == NULL)
129 return;
130 tmr = q->timer;
131 if (tmr == NULL)
132 return;
133 spin_lock_irqsave(&tmr->lock, flags);
134 if (!tmr->running) {
135 spin_unlock_irqrestore(&tmr->lock, flags);
136 return;
137 }
138
139 resolution *= ticks;
140 if (tmr->skew != tmr->skew_base) {
141 /* FIXME: assuming skew_base = 0x10000 */
142 resolution = (resolution >> 16) * tmr->skew +
143 (((resolution & 0xffff) * tmr->skew) >> 16);
144 }
145
146 /* update timer */
147 snd_seq_inc_time_nsec(&tmr->cur_time, resolution);
148
149 /* calculate current tick */
150 snd_seq_timer_update_tick(&tmr->tick, resolution);
151
152 /* register actual time of this timer update */
153 ktime_get_ts64(&tmr->last_update);
154
155 spin_unlock_irqrestore(&tmr->lock, flags);
156
157 /* check queues and dispatch events */
158 snd_seq_check_queue(q, 1, 0);
159 }
160
161 /* set current tempo */
snd_seq_timer_set_tempo(struct snd_seq_timer * tmr,int tempo)162 int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
163 {
164 unsigned long flags;
165
166 if (snd_BUG_ON(!tmr))
167 return -EINVAL;
168 if (tempo <= 0)
169 return -EINVAL;
170 spin_lock_irqsave(&tmr->lock, flags);
171 if ((unsigned int)tempo != tmr->tempo) {
172 tmr->tempo = tempo;
173 snd_seq_timer_set_tick_resolution(tmr);
174 }
175 spin_unlock_irqrestore(&tmr->lock, flags);
176 return 0;
177 }
178
179 /* set current tempo and ppq in a shot */
snd_seq_timer_set_tempo_ppq(struct snd_seq_timer * tmr,int tempo,int ppq)180 int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq)
181 {
182 int changed;
183 unsigned long flags;
184
185 if (snd_BUG_ON(!tmr))
186 return -EINVAL;
187 if (tempo <= 0 || ppq <= 0)
188 return -EINVAL;
189 spin_lock_irqsave(&tmr->lock, flags);
190 if (tmr->running && (ppq != tmr->ppq)) {
191 /* refuse to change ppq on running timers */
192 /* because it will upset the song position (ticks) */
193 spin_unlock_irqrestore(&tmr->lock, flags);
194 pr_debug("ALSA: seq: cannot change ppq of a running timer\n");
195 return -EBUSY;
196 }
197 changed = (tempo != tmr->tempo) || (ppq != tmr->ppq);
198 tmr->tempo = tempo;
199 tmr->ppq = ppq;
200 if (changed)
201 snd_seq_timer_set_tick_resolution(tmr);
202 spin_unlock_irqrestore(&tmr->lock, flags);
203 return 0;
204 }
205
206 /* set current tick position */
snd_seq_timer_set_position_tick(struct snd_seq_timer * tmr,snd_seq_tick_time_t position)207 int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
208 snd_seq_tick_time_t position)
209 {
210 unsigned long flags;
211
212 if (snd_BUG_ON(!tmr))
213 return -EINVAL;
214
215 spin_lock_irqsave(&tmr->lock, flags);
216 tmr->tick.cur_tick = position;
217 tmr->tick.fraction = 0;
218 spin_unlock_irqrestore(&tmr->lock, flags);
219 return 0;
220 }
221
222 /* set current real-time position */
snd_seq_timer_set_position_time(struct snd_seq_timer * tmr,snd_seq_real_time_t position)223 int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
224 snd_seq_real_time_t position)
225 {
226 unsigned long flags;
227
228 if (snd_BUG_ON(!tmr))
229 return -EINVAL;
230
231 snd_seq_sanity_real_time(&position);
232 spin_lock_irqsave(&tmr->lock, flags);
233 tmr->cur_time = position;
234 spin_unlock_irqrestore(&tmr->lock, flags);
235 return 0;
236 }
237
238 /* set timer skew */
snd_seq_timer_set_skew(struct snd_seq_timer * tmr,unsigned int skew,unsigned int base)239 int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
240 unsigned int base)
241 {
242 unsigned long flags;
243
244 if (snd_BUG_ON(!tmr))
245 return -EINVAL;
246
247 /* FIXME */
248 if (base != SKEW_BASE) {
249 pr_debug("ALSA: seq: invalid skew base 0x%x\n", base);
250 return -EINVAL;
251 }
252 spin_lock_irqsave(&tmr->lock, flags);
253 tmr->skew = skew;
254 spin_unlock_irqrestore(&tmr->lock, flags);
255 return 0;
256 }
257
snd_seq_timer_open(struct snd_seq_queue * q)258 int snd_seq_timer_open(struct snd_seq_queue *q)
259 {
260 struct snd_timer_instance *t;
261 struct snd_seq_timer *tmr;
262 char str[32];
263 int err;
264
265 tmr = q->timer;
266 if (snd_BUG_ON(!tmr))
267 return -EINVAL;
268 if (tmr->timeri)
269 return -EBUSY;
270 sprintf(str, "sequencer queue %i", q->queue);
271 if (tmr->type != SNDRV_SEQ_TIMER_ALSA) /* standard ALSA timer */
272 return -EINVAL;
273 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
274 tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
275 t = snd_timer_instance_new(str);
276 if (!t)
277 return -ENOMEM;
278 t->callback = snd_seq_timer_interrupt;
279 t->callback_data = q;
280 t->flags |= SNDRV_TIMER_IFLG_AUTO;
281 err = snd_timer_open(t, &tmr->alsa_id, q->queue);
282 if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
283 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
284 tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
285 struct snd_timer_id tid;
286 memset(&tid, 0, sizeof(tid));
287 tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
288 tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
289 tid.card = -1;
290 tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
291 err = snd_timer_open(t, &tid, q->queue);
292 }
293 }
294 if (err < 0) {
295 pr_err("ALSA: seq fatal error: cannot create timer (%i)\n", err);
296 snd_timer_instance_free(t);
297 return err;
298 }
299 spin_lock_irq(&tmr->lock);
300 if (tmr->timeri)
301 err = -EBUSY;
302 else
303 tmr->timeri = t;
304 spin_unlock_irq(&tmr->lock);
305 if (err < 0) {
306 snd_timer_close(t);
307 snd_timer_instance_free(t);
308 return err;
309 }
310 return 0;
311 }
312
snd_seq_timer_close(struct snd_seq_queue * q)313 int snd_seq_timer_close(struct snd_seq_queue *q)
314 {
315 struct snd_seq_timer *tmr;
316 struct snd_timer_instance *t;
317
318 tmr = q->timer;
319 if (snd_BUG_ON(!tmr))
320 return -EINVAL;
321 spin_lock_irq(&tmr->lock);
322 t = tmr->timeri;
323 tmr->timeri = NULL;
324 spin_unlock_irq(&tmr->lock);
325 if (t) {
326 snd_timer_close(t);
327 snd_timer_instance_free(t);
328 }
329 return 0;
330 }
331
seq_timer_stop(struct snd_seq_timer * tmr)332 static int seq_timer_stop(struct snd_seq_timer *tmr)
333 {
334 if (! tmr->timeri)
335 return -EINVAL;
336 if (!tmr->running)
337 return 0;
338 tmr->running = 0;
339 snd_timer_pause(tmr->timeri);
340 return 0;
341 }
342
snd_seq_timer_stop(struct snd_seq_timer * tmr)343 int snd_seq_timer_stop(struct snd_seq_timer *tmr)
344 {
345 unsigned long flags;
346 int err;
347
348 spin_lock_irqsave(&tmr->lock, flags);
349 err = seq_timer_stop(tmr);
350 spin_unlock_irqrestore(&tmr->lock, flags);
351 return err;
352 }
353
initialize_timer(struct snd_seq_timer * tmr)354 static int initialize_timer(struct snd_seq_timer *tmr)
355 {
356 struct snd_timer *t;
357 unsigned long freq;
358
359 t = tmr->timeri->timer;
360 if (!t)
361 return -EINVAL;
362
363 freq = tmr->preferred_resolution;
364 if (!freq)
365 freq = DEFAULT_FREQUENCY;
366 else if (freq < MIN_FREQUENCY)
367 freq = MIN_FREQUENCY;
368 else if (freq > MAX_FREQUENCY)
369 freq = MAX_FREQUENCY;
370
371 tmr->ticks = 1;
372 if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
373 unsigned long r = snd_timer_resolution(tmr->timeri);
374 if (r) {
375 tmr->ticks = (unsigned int)(1000000000uL / (r * freq));
376 if (! tmr->ticks)
377 tmr->ticks = 1;
378 }
379 }
380 tmr->initialized = 1;
381 return 0;
382 }
383
seq_timer_start(struct snd_seq_timer * tmr)384 static int seq_timer_start(struct snd_seq_timer *tmr)
385 {
386 if (! tmr->timeri)
387 return -EINVAL;
388 if (tmr->running)
389 seq_timer_stop(tmr);
390 seq_timer_reset(tmr);
391 if (initialize_timer(tmr) < 0)
392 return -EINVAL;
393 snd_timer_start(tmr->timeri, tmr->ticks);
394 tmr->running = 1;
395 ktime_get_ts64(&tmr->last_update);
396 return 0;
397 }
398
snd_seq_timer_start(struct snd_seq_timer * tmr)399 int snd_seq_timer_start(struct snd_seq_timer *tmr)
400 {
401 unsigned long flags;
402 int err;
403
404 spin_lock_irqsave(&tmr->lock, flags);
405 err = seq_timer_start(tmr);
406 spin_unlock_irqrestore(&tmr->lock, flags);
407 return err;
408 }
409
seq_timer_continue(struct snd_seq_timer * tmr)410 static int seq_timer_continue(struct snd_seq_timer *tmr)
411 {
412 if (! tmr->timeri)
413 return -EINVAL;
414 if (tmr->running)
415 return -EBUSY;
416 if (! tmr->initialized) {
417 seq_timer_reset(tmr);
418 if (initialize_timer(tmr) < 0)
419 return -EINVAL;
420 }
421 snd_timer_start(tmr->timeri, tmr->ticks);
422 tmr->running = 1;
423 ktime_get_ts64(&tmr->last_update);
424 return 0;
425 }
426
snd_seq_timer_continue(struct snd_seq_timer * tmr)427 int snd_seq_timer_continue(struct snd_seq_timer *tmr)
428 {
429 unsigned long flags;
430 int err;
431
432 spin_lock_irqsave(&tmr->lock, flags);
433 err = seq_timer_continue(tmr);
434 spin_unlock_irqrestore(&tmr->lock, flags);
435 return err;
436 }
437
438 /* return current 'real' time. use timeofday() to get better granularity. */
snd_seq_timer_get_cur_time(struct snd_seq_timer * tmr,bool adjust_ktime)439 snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
440 bool adjust_ktime)
441 {
442 snd_seq_real_time_t cur_time;
443 unsigned long flags;
444
445 spin_lock_irqsave(&tmr->lock, flags);
446 cur_time = tmr->cur_time;
447 if (adjust_ktime && tmr->running) {
448 struct timespec64 tm;
449
450 ktime_get_ts64(&tm);
451 tm = timespec64_sub(tm, tmr->last_update);
452 cur_time.tv_nsec += tm.tv_nsec;
453 cur_time.tv_sec += tm.tv_sec;
454 snd_seq_sanity_real_time(&cur_time);
455 }
456 spin_unlock_irqrestore(&tmr->lock, flags);
457 return cur_time;
458 }
459
460 /* TODO: use interpolation on tick queue (will only be useful for very
461 high PPQ values) */
snd_seq_timer_get_cur_tick(struct snd_seq_timer * tmr)462 snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
463 {
464 snd_seq_tick_time_t cur_tick;
465 unsigned long flags;
466
467 spin_lock_irqsave(&tmr->lock, flags);
468 cur_tick = tmr->tick.cur_tick;
469 spin_unlock_irqrestore(&tmr->lock, flags);
470 return cur_tick;
471 }
472
473
474 #ifdef CONFIG_SND_PROC_FS
475 /* exported to seq_info.c */
snd_seq_info_timer_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)476 void snd_seq_info_timer_read(struct snd_info_entry *entry,
477 struct snd_info_buffer *buffer)
478 {
479 int idx;
480 struct snd_seq_queue *q;
481 struct snd_seq_timer *tmr;
482 struct snd_timer_instance *ti;
483 unsigned long resolution;
484
485 for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
486 q = queueptr(idx);
487 if (q == NULL)
488 continue;
489 mutex_lock(&q->timer_mutex);
490 tmr = q->timer;
491 if (!tmr)
492 goto unlock;
493 ti = tmr->timeri;
494 if (!ti)
495 goto unlock;
496 snd_iprintf(buffer, "Timer for queue %i : %s\n", q->queue, ti->timer->name);
497 resolution = snd_timer_resolution(ti) * tmr->ticks;
498 snd_iprintf(buffer, " Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
499 snd_iprintf(buffer, " Skew : %u / %u\n", tmr->skew, tmr->skew_base);
500 unlock:
501 mutex_unlock(&q->timer_mutex);
502 queuefree(q);
503 }
504 }
505 #endif /* CONFIG_SND_PROC_FS */
506
507