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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ALSA sequencer Timer
4 * Copyright (c) 1998-1999 by Frank van de Pol <[email protected]>
5 * Jaroslav Kysela <[email protected]>
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
21static 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) */
42struct snd_seq_timer *snd_seq_timer_new(void)
43{
44 struct snd_seq_timer *tmr;
45
46 tmr = kzalloc_obj(*tmr);
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) */
61void snd_seq_timer_delete(struct snd_seq_timer **tmr)
62{
63 struct snd_seq_timer *t = *tmr;
64 struct snd_timer_instance *ti;
65
66 if (t == NULL) {
67 pr_debug("ALSA: seq: snd_seq_timer_delete() called with NULL timer\n");
68 return;
69 }
70
71 scoped_guard(spinlock_irq, &t->lock) {
72 ti = t->timeri;
73 t->timeri = NULL;
74 }
75 if (ti) {
76 snd_timer_close(ti);
77 snd_timer_instance_free(ti);
78 }
79
80 *tmr = NULL;
81 t->running = 0;
82
83 /* reset time */
84 snd_seq_timer_stop(t);
85 snd_seq_timer_reset(t);
86
87 kfree(t);
88}
89
90void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
91{
92 guard(spinlock_irqsave)(&tmr->lock);
93 /* setup defaults */
94 tmr->ppq = 96; /* 96 PPQ */
95 tmr->tempo = 500000; /* 120 BPM */
96 tmr->tempo_base = 1000; /* 1us */
97 snd_seq_timer_set_tick_resolution(tmr);
98 tmr->running = 0;
99
100 tmr->type = SNDRV_SEQ_TIMER_ALSA;
101 tmr->alsa_id.dev_class = seq_default_timer_class;
102 tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
103 tmr->alsa_id.card = seq_default_timer_card;
104 tmr->alsa_id.device = seq_default_timer_device;
105 tmr->alsa_id.subdevice = seq_default_timer_subdevice;
106 tmr->preferred_resolution = seq_default_timer_resolution;
107
108 tmr->skew = tmr->skew_base = SKEW_BASE;
109}
110
111static void seq_timer_reset(struct snd_seq_timer *tmr)
112{
113 /* reset time & songposition */
114 tmr->cur_time.tv_sec = 0;
115 tmr->cur_time.tv_nsec = 0;
116
117 tmr->tick.cur_tick = 0;
118 tmr->tick.fraction = 0;
119}
120
121void snd_seq_timer_reset(struct snd_seq_timer *tmr)
122{
123 guard(spinlock_irqsave)(&tmr->lock);
124 seq_timer_reset(tmr);
125}
126
127
128/* called by timer interrupt routine. the period time since previous invocation is passed */
129static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
130 unsigned long resolution,
131 unsigned long ticks)
132{
133 struct snd_seq_queue *q = timeri->callback_data;
134 struct snd_seq_timer *tmr;
135
136 if (q == NULL)
137 return;
138 tmr = q->timer;
139 if (tmr == NULL)
140 return;
141
142 scoped_guard(spinlock_irqsave, &tmr->lock) {
143 if (!tmr->running)
144 return;
145
146 resolution *= ticks;
147 if (tmr->skew != tmr->skew_base) {
148 /* FIXME: assuming skew_base = 0x10000 */
149 resolution = (resolution >> 16) * tmr->skew +
150 (((resolution & 0xffff) * tmr->skew) >> 16);
151 }
152
153 /* update timer */
154 snd_seq_inc_time_nsec(&tmr->cur_time, resolution);
155
156 /* calculate current tick */
157 snd_seq_timer_update_tick(&tmr->tick, resolution);
158
159 /* register actual time of this timer update */
160 ktime_get_ts64(&tmr->last_update);
161 }
162
163 /* check queues and dispatch events */
164 snd_seq_check_queue(q, 1, 0);
165}
166
167/* set current tempo */
168int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
169{
170 if (snd_BUG_ON(!tmr))
171 return -EINVAL;
172 if (tempo <= 0)
173 return -EINVAL;
174 guard(spinlock_irqsave)(&tmr->lock);
175 if ((unsigned int)tempo != tmr->tempo) {
176 tmr->tempo = tempo;
177 snd_seq_timer_set_tick_resolution(tmr);
178 }
179 return 0;
180}
181
182/* set current tempo, ppq and base in a shot */
183int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq,
184 unsigned int tempo_base)
185{
186 int changed;
187
188 if (snd_BUG_ON(!tmr))
189 return -EINVAL;
190 if (tempo <= 0 || ppq <= 0)
191 return -EINVAL;
192 /* allow only 10ns or 1us tempo base for now */
193 if (tempo_base && tempo_base != 10 && tempo_base != 1000)
194 return -EINVAL;
195 guard(spinlock_irqsave)(&tmr->lock);
196 if (tmr->running && (ppq != tmr->ppq)) {
197 /* refuse to change ppq on running timers */
198 /* because it will upset the song position (ticks) */
199 pr_debug("ALSA: seq: cannot change ppq of a running timer\n");
200 return -EBUSY;
201 }
202 changed = (tempo != tmr->tempo) || (ppq != tmr->ppq);
203 tmr->tempo = tempo;
204 tmr->ppq = ppq;
205 tmr->tempo_base = tempo_base ? tempo_base : 1000;
206 if (changed)
207 snd_seq_timer_set_tick_resolution(tmr);
208 return 0;
209}
210
211/* set current tick position */
212int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
213 snd_seq_tick_time_t position)
214{
215 if (snd_BUG_ON(!tmr))
216 return -EINVAL;
217
218 guard(spinlock_irqsave)(&tmr->lock);
219 tmr->tick.cur_tick = position;
220 tmr->tick.fraction = 0;
221 return 0;
222}
223
224/* set current real-time position */
225int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
226 snd_seq_real_time_t position)
227{
228 if (snd_BUG_ON(!tmr))
229 return -EINVAL;
230
231 snd_seq_sanity_real_time(&position);
232 guard(spinlock_irqsave)(&tmr->lock);
233 tmr->cur_time = position;
234 return 0;
235}
236
237/* set timer skew */
238int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
239 unsigned int base)
240{
241 if (snd_BUG_ON(!tmr))
242 return -EINVAL;
243
244 /* FIXME */
245 if (base != SKEW_BASE) {
246 pr_debug("ALSA: seq: invalid skew base 0x%x\n", base);
247 return -EINVAL;
248 }
249 guard(spinlock_irqsave)(&tmr->lock);
250 tmr->skew = skew;
251 return 0;
252}
253
254int snd_seq_timer_open(struct snd_seq_queue *q)
255{
256 struct snd_timer_instance *t;
257 struct snd_seq_timer *tmr;
258 char str[32];
259 int err;
260
261 tmr = q->timer;
262 if (snd_BUG_ON(!tmr))
263 return -EINVAL;
264 if (tmr->timeri)
265 return -EBUSY;
266 sprintf(str, "sequencer queue %i", q->queue);
267 if (tmr->type != SNDRV_SEQ_TIMER_ALSA) /* standard ALSA timer */
268 return -EINVAL;
269 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
270 tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
271 t = snd_timer_instance_new(str);
272 if (!t)
273 return -ENOMEM;
274 t->callback = snd_seq_timer_interrupt;
275 t->callback_data = q;
276 t->flags |= SNDRV_TIMER_IFLG_AUTO;
277 err = snd_timer_open(t, &tmr->alsa_id, q->queue);
278 if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
279 if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
280 tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
281 struct snd_timer_id tid;
282 memset(&tid, 0, sizeof(tid));
283 tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
284 tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
285 tid.card = -1;
286 tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
287 err = snd_timer_open(t, &tid, q->queue);
288 }
289 }
290 if (err < 0) {
291 pr_err("ALSA: seq fatal error: cannot create timer (%i)\n", err);
292 snd_timer_instance_free(t);
293 return err;
294 }
295 scoped_guard(spinlock_irq, &tmr->lock) {
296 if (tmr->timeri)
297 err = -EBUSY;
298 else
299 tmr->timeri = t;
300 }
301 if (err < 0) {
302 snd_timer_close(t);
303 snd_timer_instance_free(t);
304 return err;
305 }
306 return 0;
307}
308
309int snd_seq_timer_close(struct snd_seq_queue *q)
310{
311 struct snd_seq_timer *tmr;
312 struct snd_timer_instance *t;
313
314 tmr = q->timer;
315 if (snd_BUG_ON(!tmr))
316 return -EINVAL;
317 scoped_guard(spinlock_irq, &tmr->lock) {
318 t = tmr->timeri;
319 tmr->timeri = NULL;
320 }
321 if (t) {
322 snd_timer_close(t);
323 snd_timer_instance_free(t);
324 }
325 return 0;
326}
327
328static int seq_timer_stop(struct snd_seq_timer *tmr)
329{
330 if (! tmr->timeri)
331 return -EINVAL;
332 if (!tmr->running)
333 return 0;
334 tmr->running = 0;
335 snd_timer_pause(tmr->timeri);
336 return 0;
337}
338
339int snd_seq_timer_stop(struct snd_seq_timer *tmr)
340{
341 guard(spinlock_irqsave)(&tmr->lock);
342 return seq_timer_stop(tmr);
343}
344
345static int initialize_timer(struct snd_seq_timer *tmr)
346{
347 unsigned long freq;
348
349 struct snd_timer *t __free(snd_timeri_timer) =
350 snd_timeri_timer_get(tmr->timeri);
351 if (!t)
352 return -EINVAL;
353
354 freq = tmr->preferred_resolution;
355 if (!freq)
356 freq = DEFAULT_FREQUENCY;
357 else if (freq < MIN_FREQUENCY)
358 freq = MIN_FREQUENCY;
359 else if (freq > MAX_FREQUENCY)
360 freq = MAX_FREQUENCY;
361
362 tmr->ticks = 1;
363 if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
364 unsigned long r = snd_timer_resolution(tmr->timeri);
365 unsigned long den;
366
367 if (r && !check_mul_overflow(r, freq, &den))
368 tmr->ticks = max(1U, (unsigned int)(1000000000uL / den));
369 }
370 tmr->initialized = 1;
371 return 0;
372}
373
374static int seq_timer_start(struct snd_seq_timer *tmr)
375{
376 if (! tmr->timeri)
377 return -EINVAL;
378 if (tmr->running)
379 seq_timer_stop(tmr);
380 seq_timer_reset(tmr);
381 if (initialize_timer(tmr) < 0)
382 return -EINVAL;
383 snd_timer_start(tmr->timeri, tmr->ticks);
384 tmr->running = 1;
385 ktime_get_ts64(&tmr->last_update);
386 return 0;
387}
388
389int snd_seq_timer_start(struct snd_seq_timer *tmr)
390{
391 guard(spinlock_irqsave)(&tmr->lock);
392 return seq_timer_start(tmr);
393}
394
395static int seq_timer_continue(struct snd_seq_timer *tmr)
396{
397 if (! tmr->timeri)
398 return -EINVAL;
399 if (tmr->running)
400 return -EBUSY;
401 if (! tmr->initialized) {
402 seq_timer_reset(tmr);
403 if (initialize_timer(tmr) < 0)
404 return -EINVAL;
405 }
406 snd_timer_start(tmr->timeri, tmr->ticks);
407 tmr->running = 1;
408 ktime_get_ts64(&tmr->last_update);
409 return 0;
410}
411
412int snd_seq_timer_continue(struct snd_seq_timer *tmr)
413{
414 guard(spinlock_irqsave)(&tmr->lock);
415 return seq_timer_continue(tmr);
416}
417
418/* return current 'real' time. use timeofday() to get better granularity. */
419snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr,
420 bool adjust_ktime)
421{
422 snd_seq_real_time_t cur_time;
423
424 guard(spinlock_irqsave)(&tmr->lock);
425 cur_time = tmr->cur_time;
426 if (adjust_ktime && tmr->running) {
427 struct timespec64 tm;
428
429 ktime_get_ts64(&tm);
430 tm = timespec64_sub(tm, tmr->last_update);
431 cur_time.tv_nsec += tm.tv_nsec;
432 cur_time.tv_sec += tm.tv_sec;
433 snd_seq_sanity_real_time(&cur_time);
434 }
435 return cur_time;
436}
437
438/* TODO: use interpolation on tick queue (will only be useful for very
439 high PPQ values) */
440snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
441{
442 guard(spinlock_irqsave)(&tmr->lock);
443 return tmr->tick.cur_tick;
444}
445
446
447#ifdef CONFIG_SND_PROC_FS
448/* exported to seq_info.c */
449void snd_seq_info_timer_read(struct snd_info_entry *entry,
450 struct snd_info_buffer *buffer)
451{
452 int idx;
453 struct snd_seq_timer *tmr;
454 struct snd_timer_instance *ti;
455 unsigned long resolution;
456
457 for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
458 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(idx);
459
460 if (q == NULL)
461 continue;
462 scoped_guard(mutex, &q->timer_mutex) {
463 tmr = q->timer;
464 if (!tmr)
465 break;
466 ti = tmr->timeri;
467 if (!ti)
468 break;
469
470 struct snd_timer *t __free(snd_timeri_timer) =
471 snd_timeri_timer_get(ti);
472 snd_iprintf(buffer, "Timer for queue %i : %s\n",
473 q->queue,
474 t ? t->name : "DEAD");
475 resolution = snd_timer_resolution(ti) * tmr->ticks;
476 snd_iprintf(buffer, " Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
477 snd_iprintf(buffer, " Skew : %u / %u\n", tmr->skew, tmr->skew_base);
478 }
479 }
480}
481#endif /* CONFIG_SND_PROC_FS */
482