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 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) */ 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) */ 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 76 void snd_seq_timer_defaults(struct snd_seq_timer * tmr) 77 { 78 guard(spinlock_irqsave)(&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 96 static 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 } 105 106 void snd_seq_timer_reset(struct snd_seq_timer *tmr) 107 { 108 guard(spinlock_irqsave)(&tmr->lock); 109 seq_timer_reset(tmr); 110 } 111 112 113 /* called by timer interrupt routine. the period time since previous invocation is passed */ 114 static 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(&tmr->cur_time, resolution); 140 141 /* calculate current tick */ 142 snd_seq_timer_update_tick(&tmr->tick, resolution); 143 144 /* register actual time of this timer update */ 145 ktime_get_ts64(&tmr->last_update); 146 } 147 148 /* check queues and dispatch events */ 149 snd_seq_check_queue(q, 1, 0); 150 } 151 152 /* set current tempo */ 153 int 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)(&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 */ 168 int 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)(&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 */ 192 int 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)(&tmr->lock); 199 tmr->tick.cur_tick = position; 200 tmr->tick.fraction = 0; 201 return 0; 202 } 203 204 /* set current real-time position */ 205 int 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(&position); 212 guard(spinlock_irqsave)(&tmr->lock); 213 tmr->cur_time = position; 214 return 0; 215 } 216 217 /* set timer skew */ 218 int 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)(&tmr->lock); 230 tmr->skew = skew; 231 return 0; 232 } 233 234 int 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(str, "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(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(t, &tmr->alsa_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(t, &tid, 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(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(t); 283 snd_timer_instance_free(t); 284 return err; 285 } 286 return 0; 287 } 288 289 int 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(t); 303 snd_timer_instance_free(t); 304 } 305 return 0; 306 } 307 308 static 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(tmr->timeri); 316 return 0; 317 } 318 319 int snd_seq_timer_stop(struct snd_seq_timer *tmr) 320 { 321 guard(spinlock_irqsave)(&tmr->lock); 322 return seq_timer_stop(tmr); 323 } 324 325 static 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(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 } 354 355 static 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(tmr->timeri, tmr->ticks); 365 tmr->running = 1; 366 ktime_get_ts64(&tmr->last_update); 367 return 0; 368 } 369 370 int snd_seq_timer_start(struct snd_seq_timer *tmr) 371 { 372 guard(spinlock_irqsave)(&tmr->lock); 373 return seq_timer_start(tmr); 374 } 375 376 static 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(tmr->timeri, tmr->ticks); 388 tmr->running = 1; 389 ktime_get_ts64(&tmr->last_update); 390 return 0; 391 } 392 393 int snd_seq_timer_continue(struct snd_seq_timer *tmr) 394 { 395 guard(spinlock_irqsave)(&tmr->lock); 396 return seq_timer_continue(tmr); 397 } 398 399 /* return current 'real' time. use timeofday() to get better granularity. */ 400 snd_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)(&tmr->lock); 406 cur_time = tmr->cur_time; 407 if (adjust_ktime && tmr->running) { 408 struct timespec64 tm; 409 410 ktime_get_ts64(&tm); 411 tm = timespec64_sub(tm, 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(&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) */ 421 snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr) 422 { 423 guard(spinlock_irqsave)(&tmr->lock); 424 return tmr->tick.cur_tick; 425 } 426 427 428 #ifdef CONFIG_SND_PROC_FS 429 /* exported to seq_info.c */ 430 void 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(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(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