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
21 static void snd_seq_timer_set_tick_resolution(struct snd_seq_timer *tmr)
22 {
23 unsigned int threshold =
24 tmr->tempo_base == 1000 ? 1000000 : 10000;
25
26 if (tmr->tempo < threshold)
27 tmr->tick.resolution = (tmr->tempo * tmr->tempo_base) / tmr->ppq;
28 else {
29 /* might overflow.. */
30 unsigned int s;
31 s = tmr->tempo % tmr->ppq;
32 s = (s * tmr->tempo_base) / tmr->ppq;
33 tmr->tick.resolution = (tmr->tempo / tmr->ppq) * tmr->tempo_base;
34 tmr->tick.resolution += s;
35 }
36 if (tmr->tick.resolution <= 0)
37 tmr->tick.resolution = 1;
38 snd_seq_timer_update_tick(&tmr->tick, 0);
39 }
40
41 /* create new timer (constructor) */
42 struct snd_seq_timer *snd_seq_timer_new(void)
43 {
44 struct snd_seq_timer *tmr;
45
46 tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
47 if (!tmr)
48 return NULL;
49 spin_lock_init(&tmr->lock);
50
51 /* reset setup to defaults */
52 snd_seq_timer_defaults(tmr);
53
54 /* reset time */
55 snd_seq_timer_reset(tmr);
56
57 return tmr;
58 }
59
60 /* delete timer (destructor) */
61 void snd_seq_timer_delete(struct snd_seq_timer **tmr)
62 {
63 struct snd_seq_timer *t = *tmr;
64 *tmr = NULL;
65
66 if (t == NULL) {
67 pr_debug("ALSA: seq: snd_seq_timer_delete() called with NULL timer\n");
68 return;
69 }
70 t->running = 0;
71
72 /* reset time */
73 snd_seq_timer_stop(t);
74 snd_seq_timer_reset(t);
75
76 kfree(t);
77 }
78
79 void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
80 {
81 guard(spinlock_irqsave)(&tmr->lock);
82 /* setup defaults */
83 tmr->ppq = 96; /* 96 PPQ */
84 tmr->tempo = 500000; /* 120 BPM */
85 tmr->tempo_base = 1000; /* 1us */
86 snd_seq_timer_set_tick_resolution(tmr);
87 tmr->running = 0;
88
89 tmr->type = SNDRV_SEQ_TIMER_ALSA;
90 tmr->alsa_id.dev_class = seq_default_timer_class;
91 tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
92 tmr->alsa_id.card = seq_default_timer_card;
93 tmr->alsa_id.device = seq_default_timer_device;
94 tmr->alsa_id.subdevice = seq_default_timer_subdevice;
95 tmr->preferred_resolution = seq_default_timer_resolution;
96
97 tmr->skew = tmr->skew_base = SKEW_BASE;
98 }
99
100 static void seq_timer_reset(struct snd_seq_timer *tmr)
101 {
102 /* reset time & songposition */
103 tmr->cur_time.tv_sec = 0;
104 tmr->cur_time.tv_nsec = 0;
105
106 tmr->tick.cur_tick = 0;
107 tmr->tick.fraction = 0;
108 }
109
110 void snd_seq_timer_reset(struct snd_seq_timer *tmr)
111 {
112 guard(spinlock_irqsave)(&tmr->lock);
113 seq_timer_reset(tmr);
114 }
115
116
117 /* called by timer interrupt routine. the period time since previous invocation is passed */
118 static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
119 unsigned long resolution,
120 unsigned long ticks)
121 {
122 struct snd_seq_queue *q = timeri->callback_data;
123 struct snd_seq_timer *tmr;
124
125 if (q == NULL)
126 return;
127 tmr = q->timer;
128 if (tmr == NULL)
129 return;
130
131 scoped_guard(spinlock_irqsave, &tmr->lock) {
132 if (!tmr->running)
133 return;
134
135 resolution *= ticks;
136 if (tmr->skew != tmr->skew_base) {
137 /* FIXME: assuming skew_base = 0x10000 */
138 resolution = (resolution >> 16) * tmr->skew +
139 (((resolution & 0xffff) * tmr->skew) >> 16);
140 }
141
142 /* update timer */
143 snd_seq_inc_time_nsec(&tmr->cur_time, resolution);
144
145 /* calculate current tick */
146 snd_seq_timer_update_tick(&tmr->tick, resolution);
147
148 /* register actual time of this timer update */
149 ktime_get_ts64(&tmr->last_update);
150 }
151
152 /* check queues and dispatch events */
153 snd_seq_check_queue(q, 1, 0);
154 }
155
156 /* set current tempo */
157 int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
158 {
159 if (snd_BUG_ON(!tmr))
160 return -EINVAL;
161 if (tempo <= 0)
162 return -EINVAL;
163 guard(spinlock_irqsave)(&tmr->lock);
164 if ((unsigned int)tempo != tmr->tempo) {
165 tmr->tempo = tempo;
166 snd_seq_timer_set_tick_resolution(tmr);
167 }
168 return 0;
169 }
170
171 /* set current tempo, ppq and base in a shot */
172 int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq,
173 unsigned int tempo_base)
174 {
175 int changed;
176
177 if (snd_BUG_ON(!tmr))
178 return -EINVAL;
179 if (tempo <= 0 || ppq <= 0)
180 return -EINVAL;
181 /* allow only 10ns or 1us tempo base for now */
182 if (tempo_base && tempo_base != 10 && tempo_base != 1000)
183 return -EINVAL;
184 guard(spinlock_irqsave)(&tmr->lock);
185 if (tmr->running && (ppq != tmr->ppq)) {
186 /* refuse to change ppq on running timers */
187 /* because it will upset the song position (ticks) */
188 pr_debug("ALSA: seq: cannot change ppq of a running timer\n");
189 return -EBUSY;
190 }
191 changed = (tempo != tmr->tempo) || (ppq != tmr->ppq);
192 tmr->tempo = tempo;
193 tmr->ppq = ppq;
194 tmr->tempo_base = tempo_base ? tempo_base : 1000;
195 if (changed)
196 snd_seq_timer_set_tick_resolution(tmr);
197 return 0;
198 }
199
200 /* set current tick position */
201 int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
202 snd_seq_tick_time_t position)
203 {
204 if (snd_BUG_ON(!tmr))
205 return -EINVAL;
206
207 guard(spinlock_irqsave)(&tmr->lock);
208 tmr->tick.cur_tick = position;
209 tmr->tick.fraction = 0;
210 return 0;
211 }
212
213 /* set current real-time position */
214 int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
215 snd_seq_real_time_t position)
216 {
217 if (snd_BUG_ON(!tmr))
218 return -EINVAL;
219
220 snd_seq_sanity_real_time(&position);
221 guard(spinlock_irqsave)(&tmr->lock);
222 tmr->cur_time = position;
223 return 0;
224 }
225
226 /* set timer skew */
227 int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
228 unsigned int base)
229 {
230 if (snd_BUG_ON(!tmr))
231 return -EINVAL;
232
233 /* FIXME */
234 if (base != SKEW_BASE) {
235 pr_debug("ALSA: seq: invalid skew base 0x%x\n", base);
236 return -EINVAL;
237 }
238 guard(spinlock_irqsave)(&tmr->lock);
239 tmr->skew = skew;
240 return 0;
241 }
242
243 int snd_seq_timer_open(struct snd_seq_queue *q)
244 {
245 struct snd_timer_instance *t;
246 struct snd_seq_timer *tmr;
247 char str[32];
248 int err;
249
250 tmr = q->timer;
251 if (snd_BUG_ON(!tmr))
252 return -EINVAL;
253 if (tmr->timeri)
254 return -EBUSY;
255 sprintf(str, "sequencer queue %i", q->queue);
256 if (tmr->type != SNDRV_SEQ_TIMER_ALSA) /* standard ALSA timer */
257 return -EINVAL;
258 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
259 tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
260 t = snd_timer_instance_new(str);
261 if (!t)
262 return -ENOMEM;
263 t->callback = snd_seq_timer_interrupt;
264 t->callback_data = q;
265 t->flags |= SNDRV_TIMER_IFLG_AUTO;
266 err = snd_timer_open(t, &tmr->alsa_id, q->queue);
267 if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
268 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
269 tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
270 struct snd_timer_id tid;
271 memset(&tid, 0, sizeof(tid));
272 tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
273 tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
274 tid.card = -1;
275 tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
276 err = snd_timer_open(t, &tid, q->queue);
277 }
278 }
279 if (err < 0) {
280 pr_err("ALSA: seq fatal error: cannot create timer (%i)\n", err);
281 snd_timer_instance_free(t);
282 return err;
283 }
284 scoped_guard(spinlock_irq, &tmr->lock) {
285 if (tmr->timeri)
286 err = -EBUSY;
287 else
288 tmr->timeri = t;
289 }
290 if (err < 0) {
291 snd_timer_close(t);
292 snd_timer_instance_free(t);
293 return err;
294 }
295 return 0;
296 }
297
298 int snd_seq_timer_close(struct snd_seq_queue *q)
299 {
300 struct snd_seq_timer *tmr;
301 struct snd_timer_instance *t;
302
303 tmr = q->timer;
304 if (snd_BUG_ON(!tmr))
305 return -EINVAL;
306 scoped_guard(spinlock_irq, &tmr->lock) {
307 t = tmr->timeri;
308 tmr->timeri = NULL;
309 }
310 if (t) {
311 snd_timer_close(t);
312 snd_timer_instance_free(t);
313 }
314 return 0;
315 }
316
317 static int seq_timer_stop(struct snd_seq_timer *tmr)
318 {
319 if (! tmr->timeri)
320 return -EINVAL;
321 if (!tmr->running)
322 return 0;
323 tmr->running = 0;
324 snd_timer_pause(tmr->timeri);
325 return 0;
326 }
327
328 int snd_seq_timer_stop(struct snd_seq_timer *tmr)
329 {
330 guard(spinlock_irqsave)(&tmr->lock);
331 return seq_timer_stop(tmr);
332 }
333
334 static int initialize_timer(struct snd_seq_timer *tmr)
335 {
336 struct snd_timer *t;
337 unsigned long freq;
338
339 t = tmr->timeri->timer;
340 if (!t)
341 return -EINVAL;
342
343 freq = tmr->preferred_resolution;
344 if (!freq)
345 freq = DEFAULT_FREQUENCY;
346 else if (freq < MIN_FREQUENCY)
347 freq = MIN_FREQUENCY;
348 else if (freq > MAX_FREQUENCY)
349 freq = MAX_FREQUENCY;
350
351 tmr->ticks = 1;
352 if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
353 unsigned long r = snd_timer_resolution(tmr->timeri);
354 if (r) {
355 tmr->ticks = (unsigned int)(1000000000uL / (r * freq));
356 if (! tmr->ticks)
357 tmr->ticks = 1;
358 }
359 }
360 tmr->initialized = 1;
361 return 0;
362 }
363
364 static int seq_timer_start(struct snd_seq_timer *tmr)
365 {
366 if (! tmr->timeri)
367 return -EINVAL;
368 if (tmr->running)
369 seq_timer_stop(tmr);
370 seq_timer_reset(tmr);
371 if (initialize_timer(tmr) < 0)
372 return -EINVAL;
373 snd_timer_start(tmr->timeri, tmr->ticks);
374 tmr->running = 1;
375 ktime_get_ts64(&tmr->last_update);
376 return 0;
377 }
378
379 int snd_seq_timer_start(struct snd_seq_timer *tmr)
380 {
381 guard(spinlock_irqsave)(&tmr->lock);
382 return seq_timer_start(tmr);
383 }
384
385 static int seq_timer_continue(struct snd_seq_timer *tmr)
386 {
387 if (! tmr->timeri)
388 return -EINVAL;
389 if (tmr->running)
390 return -EBUSY;
391 if (! tmr->initialized) {
392 seq_timer_reset(tmr);
393 if (initialize_timer(tmr) < 0)
394 return -EINVAL;
395 }
396 snd_timer_start(tmr->timeri, tmr->ticks);
397 tmr->running = 1;
398 ktime_get_ts64(&tmr->last_update);
399 return 0;
400 }
401
402 int snd_seq_timer_continue(struct snd_seq_timer *tmr)
403 {
404 guard(spinlock_irqsave)(&tmr->lock);
405 return seq_timer_continue(tmr);
406 }
407
408 /* return current 'real' time. use timeofday() to get better granularity. */
409 snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
410 bool adjust_ktime)
411 {
412 snd_seq_real_time_t cur_time;
413
414 guard(spinlock_irqsave)(&tmr->lock);
415 cur_time = tmr->cur_time;
416 if (adjust_ktime && tmr->running) {
417 struct timespec64 tm;
418
419 ktime_get_ts64(&tm);
420 tm = timespec64_sub(tm, tmr->last_update);
421 cur_time.tv_nsec += tm.tv_nsec;
422 cur_time.tv_sec += tm.tv_sec;
423 snd_seq_sanity_real_time(&cur_time);
424 }
425 return cur_time;
426 }
427
428 /* TODO: use interpolation on tick queue (will only be useful for very
429 high PPQ values) */
430 snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
431 {
432 guard(spinlock_irqsave)(&tmr->lock);
433 return tmr->tick.cur_tick;
434 }
435
436
437 #ifdef CONFIG_SND_PROC_FS
438 /* exported to seq_info.c */
439 void snd_seq_info_timer_read(struct snd_info_entry *entry,
440 struct snd_info_buffer *buffer)
441 {
442 int idx;
443 struct snd_seq_queue *q;
444 struct snd_seq_timer *tmr;
445 struct snd_timer_instance *ti;
446 unsigned long resolution;
447
448 for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
449 q = queueptr(idx);
450 if (q == NULL)
451 continue;
452 scoped_guard(mutex, &q->timer_mutex) {
453 tmr = q->timer;
454 if (!tmr)
455 break;
456 ti = tmr->timeri;
457 if (!ti)
458 break;
459 snd_iprintf(buffer, "Timer for queue %i : %s\n", q->queue, ti->timer->name);
460 resolution = snd_timer_resolution(ti) * tmr->ticks;
461 snd_iprintf(buffer, " Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
462 snd_iprintf(buffer, " Skew : %u / %u\n", tmr->skew, tmr->skew_base);
463 }
464 queuefree(q);
465 }
466 }
467 #endif /* CONFIG_SND_PROC_FS */
468
469
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