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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * ALSA sequencer Timer4 * 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 1016#define MAX_FREQUENCY 625017#define DEFAULT_FREQUENCY 100018 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(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) */61void 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 79void 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 100static 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 110void 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 */118static 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 */157int 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 */172int 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 */201int 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 */214int 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 */227int 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 243int 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 else288 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 298int 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 317static 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 328int snd_seq_timer_stop(struct snd_seq_timer *tmr)329{330 guard(spinlock_irqsave)(&tmr->lock);331 return seq_timer_stop(tmr);332}333 334static 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 364static 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 379int snd_seq_timer_start(struct snd_seq_timer *tmr)380{381 guard(spinlock_irqsave)(&tmr->lock);382 return seq_timer_start(tmr);383}384 385static 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 402int 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. */409snd_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 very429 high PPQ values) */430snd_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_FS438/* exported to seq_info.c */439void 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