xref: /openbmc/linux/sound/core/seq/seq_timer.c (revision 83e197a8)
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