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

source code of linux/sound/core/seq/seq_timer.c