1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Loopback soundcard 4 * 5 * Original code: 6 * Copyright (c) by Jaroslav Kysela <perex@perex.cz> 7 * 8 * More accurate positioning and full-duplex support: 9 * Copyright (c) Ahmet ��nan <ainan at mathematik.uni-freiburg.de> 10 * 11 * Major (almost complete) rewrite: 12 * Copyright (c) by Takashi Iwai <tiwai@suse.de> 13 * 14 * A next major update in 2010 (separate timers for playback and capture): 15 * Copyright (c) Jaroslav Kysela <perex@perex.cz> 16 */ 17 18#include <linux/init.h> 19#include <linux/jiffies.h> 20#include <linux/slab.h> 21#include <linux/time.h> 22#include <linux/wait.h> 23#include <linux/module.h> 24#include <linux/platform_device.h> 25#include <sound/core.h> 26#include <sound/control.h> 27#include <sound/pcm.h> 28#include <sound/pcm_params.h> 29#include <sound/info.h> 30#include <sound/initval.h> 31#include <sound/timer.h> 32 33MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 34MODULE_DESCRIPTION("A loopback soundcard"); 35MODULE_LICENSE("GPL"); 36 37#define MAX_PCM_SUBSTREAMS 8 38 39static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 40static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 41static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 42static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 43static int pcm_notify[SNDRV_CARDS]; 44static char *timer_source[SNDRV_CARDS]; 45 46module_param_array(index, int, NULL, 0444); 47MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 48module_param_array(id, charp, NULL, 0444); 49MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 50module_param_array(enable, bool, NULL, 0444); 51MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 52module_param_array(pcm_substreams, int, NULL, 0444); 53MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 54module_param_array(pcm_notify, int, NULL, 0444); 55MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 56module_param_array(timer_source, charp, NULL, 0444); 57MODULE_PARM_DESC(timer_source, "Sound card name or number and device/subdevice number of timer to be used. Empty string for jiffies timer [default]."); 58 59#define NO_PITCH 100000 60 61#define CABLE_VALID_PLAYBACK BIT(SNDRV_PCM_STREAM_PLAYBACK) 62#define CABLE_VALID_CAPTURE BIT(SNDRV_PCM_STREAM_CAPTURE) 63#define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE) 64 65struct loopback_cable; 66struct loopback_pcm; 67 68struct loopback_ops { 69 /* optional 70 * call in loopback->cable_lock 71 */ 72 int (*open)(struct loopback_pcm *dpcm); 73 /* required 74 * call in cable->lock 75 */ 76 int (*start)(struct loopback_pcm *dpcm); 77 /* required 78 * call in cable->lock 79 */ 80 int (*stop)(struct loopback_pcm *dpcm); 81 /* optional */ 82 int (*stop_sync)(struct loopback_pcm *dpcm); 83 /* optional */ 84 int (*close_substream)(struct loopback_pcm *dpcm); 85 /* optional 86 * call in loopback->cable_lock 87 */ 88 int (*close_cable)(struct loopback_pcm *dpcm); 89 /* optional 90 * call in cable->lock 91 */ 92 unsigned int (*pos_update)(struct loopback_cable *cable); 93 /* optional */ 94 void (*dpcm_info)(struct loopback_pcm *dpcm, 95 struct snd_info_buffer *buffer); 96}; 97 98struct loopback_cable { 99 spinlock_t lock; 100 struct loopback_pcm *streams[2]; 101 struct snd_pcm_hardware hw; 102 /* flags */ 103 unsigned int valid; 104 unsigned int running; 105 unsigned int pause; 106 /* timer specific */ 107 const struct loopback_ops *ops; 108 /* If sound timer is used */ 109 struct { 110 int stream; 111 struct snd_timer_id id; 112 struct work_struct event_work; 113 struct snd_timer_instance *instance; 114 } snd_timer; 115}; 116 117struct loopback_setup { 118 unsigned int notify: 1; 119 unsigned int rate_shift; 120 snd_pcm_format_t format; 121 unsigned int rate; 122 snd_pcm_access_t access; 123 unsigned int channels; 124 struct snd_ctl_elem_id active_id; 125 struct snd_ctl_elem_id format_id; 126 struct snd_ctl_elem_id rate_id; 127 struct snd_ctl_elem_id channels_id; 128 struct snd_ctl_elem_id access_id; 129}; 130 131struct loopback { 132 struct snd_card *card; 133 struct mutex cable_lock; 134 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 135 struct snd_pcm *pcm[2]; 136 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 137 const char *timer_source; 138}; 139 140struct loopback_pcm { 141 struct loopback *loopback; 142 struct snd_pcm_substream *substream; 143 struct loopback_cable *cable; 144 unsigned int pcm_buffer_size; 145 unsigned int buf_pos; /* position in buffer */ 146 unsigned int silent_size; 147 /* PCM parameters */ 148 unsigned int pcm_period_size; 149 unsigned int pcm_bps; /* bytes per second */ 150 unsigned int pcm_salign; /* bytes per sample * channels */ 151 unsigned int pcm_rate_shift; /* rate shift value */ 152 /* flags */ 153 unsigned int period_update_pending :1; 154 /* timer stuff */ 155 unsigned int irq_pos; /* fractional IRQ position in jiffies 156 * ticks 157 */ 158 unsigned int period_size_frac; /* period size in jiffies ticks */ 159 unsigned int last_drift; 160 unsigned long last_jiffies; 161 /* If jiffies timer is used */ 162 struct timer_list timer; 163 164 /* size of per channel buffer in case of non-interleaved access */ 165 unsigned int channel_buf_n; 166}; 167 168static struct platform_device *devices[SNDRV_CARDS]; 169 170static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 171{ 172 if (dpcm->pcm_rate_shift == NO_PITCH) { 173 x /= HZ; 174 } else { 175 x = div_u64(NO_PITCH * (unsigned long long)x, 176 HZ * (unsigned long long)dpcm->pcm_rate_shift); 177 } 178 return x - (x % dpcm->pcm_salign); 179} 180 181static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 182{ 183 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 184 return x * HZ; 185 } else { 186 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 187 NO_PITCH); 188 } 189 return x; 190} 191 192static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 193{ 194 int device = dpcm->substream->pstr->pcm->device; 195 196 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 197 device ^= 1; 198 return &dpcm->loopback->setup[dpcm->substream->number][device]; 199} 200 201static inline unsigned int get_notify(struct loopback_pcm *dpcm) 202{ 203 return get_setup(dpcm)->notify; 204} 205 206static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 207{ 208 return get_setup(dpcm)->rate_shift; 209} 210 211/* call in cable->lock */ 212static int loopback_jiffies_timer_start(struct loopback_pcm *dpcm) 213{ 214 unsigned long tick; 215 unsigned int rate_shift = get_rate_shift(dpcm); 216 217 if (rate_shift != dpcm->pcm_rate_shift) { 218 dpcm->pcm_rate_shift = rate_shift; 219 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 220 } 221 if (dpcm->period_size_frac <= dpcm->irq_pos) { 222 dpcm->irq_pos %= dpcm->period_size_frac; 223 dpcm->period_update_pending = 1; 224 } 225 tick = dpcm->period_size_frac - dpcm->irq_pos; 226 tick = DIV_ROUND_UP(tick, dpcm->pcm_bps); 227 mod_timer(&dpcm->timer, jiffies + tick); 228 229 return 0; 230} 231 232/* call in cable->lock */ 233static int loopback_snd_timer_start(struct loopback_pcm *dpcm) 234{ 235 struct loopback_cable *cable = dpcm->cable; 236 int err; 237 238 /* Loopback device has to use same period as timer card. Therefore 239 * wake up for each snd_pcm_period_elapsed() call of timer card. 240 */ 241 err = snd_timer_start(cable->snd_timer.instance, 1); 242 if (err < 0) { 243 /* do not report error if trying to start but already 244 * running. For example called by opposite substream 245 * of the same cable 246 */ 247 if (err == -EBUSY) 248 return 0; 249 250 pcm_err(dpcm->substream->pcm, 251 "snd_timer_start(%d,%d,%d) failed with %d", 252 cable->snd_timer.id.card, 253 cable->snd_timer.id.device, 254 cable->snd_timer.id.subdevice, 255 err); 256 } 257 258 return err; 259} 260 261/* call in cable->lock */ 262static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm) 263{ 264 del_timer(&dpcm->timer); 265 dpcm->timer.expires = 0; 266 267 return 0; 268} 269 270/* call in cable->lock */ 271static int loopback_snd_timer_stop(struct loopback_pcm *dpcm) 272{ 273 struct loopback_cable *cable = dpcm->cable; 274 int err; 275 276 /* only stop if both devices (playback and capture) are not running */ 277 if (cable->running ^ cable->pause) 278 return 0; 279 280 err = snd_timer_stop(cable->snd_timer.instance); 281 if (err < 0) { 282 pcm_err(dpcm->substream->pcm, 283 "snd_timer_stop(%d,%d,%d) failed with %d", 284 cable->snd_timer.id.card, 285 cable->snd_timer.id.device, 286 cable->snd_timer.id.subdevice, 287 err); 288 } 289 290 return err; 291} 292 293static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm) 294{ 295 del_timer_sync(&dpcm->timer); 296 297 return 0; 298} 299 300/* call in loopback->cable_lock */ 301static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm) 302{ 303 struct loopback_cable *cable = dpcm->cable; 304 305 /* snd_timer was not opened */ 306 if (!cable->snd_timer.instance) 307 return 0; 308 309 /* will only be called from free_cable() when other stream was 310 * already closed. Other stream cannot be reopened as long as 311 * loopback->cable_lock is locked. Therefore no need to lock 312 * cable->lock; 313 */ 314 snd_timer_close(cable->snd_timer.instance); 315 316 /* wait till drain work has finished if requested */ 317 cancel_work_sync(&cable->snd_timer.event_work); 318 319 snd_timer_instance_free(cable->snd_timer.instance); 320 memset(&cable->snd_timer, 0, sizeof(cable->snd_timer)); 321 322 return 0; 323} 324 325static bool is_access_interleaved(snd_pcm_access_t access) 326{ 327 switch (access) { 328 case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED: 329 case SNDRV_PCM_ACCESS_RW_INTERLEAVED: 330 return true; 331 default: 332 return false; 333 } 334}; 335 336static int loopback_check_format(struct loopback_cable *cable, int stream) 337{ 338 struct snd_pcm_runtime *runtime, *cruntime; 339 struct loopback_setup *setup; 340 struct snd_card *card; 341 int check; 342 343 if (cable->valid != CABLE_VALID_BOTH) { 344 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 345 goto __notify; 346 return 0; 347 } 348 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 349 substream->runtime; 350 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 351 substream->runtime; 352 check = runtime->format != cruntime->format || 353 runtime->rate != cruntime->rate || 354 runtime->channels != cruntime->channels || 355 is_access_interleaved(runtime->access) != 356 is_access_interleaved(cruntime->access); 357 if (!check) 358 return 0; 359 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 360 return -EIO; 361 } else { 362 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 363 substream, SNDRV_PCM_STATE_DRAINING); 364 __notify: 365 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 366 substream->runtime; 367 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 368 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 369 if (setup->format != runtime->format) { 370 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 371 &setup->format_id); 372 setup->format = runtime->format; 373 } 374 if (setup->rate != runtime->rate) { 375 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 376 &setup->rate_id); 377 setup->rate = runtime->rate; 378 } 379 if (setup->channels != runtime->channels) { 380 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 381 &setup->channels_id); 382 setup->channels = runtime->channels; 383 } 384 if (is_access_interleaved(setup->access) != 385 is_access_interleaved(runtime->access)) { 386 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 387 &setup->access_id); 388 setup->access = runtime->access; 389 } 390 } 391 return 0; 392} 393 394static void loopback_active_notify(struct loopback_pcm *dpcm) 395{ 396 snd_ctl_notify(dpcm->loopback->card, 397 SNDRV_CTL_EVENT_MASK_VALUE, 398 &get_setup(dpcm)->active_id); 399} 400 401static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 402{ 403 struct snd_pcm_runtime *runtime = substream->runtime; 404 struct loopback_pcm *dpcm = runtime->private_data; 405 struct loopback_cable *cable = dpcm->cable; 406 int err = 0, stream = 1 << substream->stream; 407 408 switch (cmd) { 409 case SNDRV_PCM_TRIGGER_START: 410 err = loopback_check_format(cable, substream->stream); 411 if (err < 0) 412 return err; 413 dpcm->last_jiffies = jiffies; 414 dpcm->pcm_rate_shift = 0; 415 dpcm->last_drift = 0; 416 spin_lock(&cable->lock); 417 cable->running |= stream; 418 cable->pause &= ~stream; 419 err = cable->ops->start(dpcm); 420 spin_unlock(&cable->lock); 421 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 422 loopback_active_notify(dpcm); 423 break; 424 case SNDRV_PCM_TRIGGER_STOP: 425 spin_lock(&cable->lock); 426 cable->running &= ~stream; 427 cable->pause &= ~stream; 428 err = cable->ops->stop(dpcm); 429 spin_unlock(&cable->lock); 430 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 431 loopback_active_notify(dpcm); 432 break; 433 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 434 case SNDRV_PCM_TRIGGER_SUSPEND: 435 spin_lock(&cable->lock); 436 cable->pause |= stream; 437 err = cable->ops->stop(dpcm); 438 spin_unlock(&cable->lock); 439 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 440 loopback_active_notify(dpcm); 441 break; 442 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 443 case SNDRV_PCM_TRIGGER_RESUME: 444 spin_lock(&cable->lock); 445 dpcm->last_jiffies = jiffies; 446 cable->pause &= ~stream; 447 err = cable->ops->start(dpcm); 448 spin_unlock(&cable->lock); 449 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 450 loopback_active_notify(dpcm); 451 break; 452 default: 453 return -EINVAL; 454 } 455 return err; 456} 457 458static void params_change(struct snd_pcm_substream *substream) 459{ 460 struct snd_pcm_runtime *runtime = substream->runtime; 461 struct loopback_pcm *dpcm = runtime->private_data; 462 struct loopback_cable *cable = dpcm->cable; 463 464 cable->hw.formats = pcm_format_to_bits(runtime->format); 465 cable->hw.rate_min = runtime->rate; 466 cable->hw.rate_max = runtime->rate; 467 cable->hw.channels_min = runtime->channels; 468 cable->hw.channels_max = runtime->channels; 469 470 if (cable->snd_timer.instance) { 471 cable->hw.period_bytes_min = 472 frames_to_bytes(runtime, runtime->period_size); 473 cable->hw.period_bytes_max = cable->hw.period_bytes_min; 474 } 475 476} 477 478static int loopback_prepare(struct snd_pcm_substream *substream) 479{ 480 struct snd_pcm_runtime *runtime = substream->runtime; 481 struct loopback_pcm *dpcm = runtime->private_data; 482 struct loopback_cable *cable = dpcm->cable; 483 int err, bps, salign; 484 485 if (cable->ops->stop_sync) { 486 err = cable->ops->stop_sync(dpcm); 487 if (err < 0) 488 return err; 489 } 490 491 salign = (snd_pcm_format_physical_width(runtime->format) * 492 runtime->channels) / 8; 493 bps = salign * runtime->rate; 494 if (bps <= 0 || salign <= 0) 495 return -EINVAL; 496 497 dpcm->buf_pos = 0; 498 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 499 dpcm->channel_buf_n = dpcm->pcm_buffer_size / runtime->channels; 500 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 501 /* clear capture buffer */ 502 dpcm->silent_size = dpcm->pcm_buffer_size; 503 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 504 runtime->buffer_size * runtime->channels); 505 } 506 507 dpcm->irq_pos = 0; 508 dpcm->period_update_pending = 0; 509 dpcm->pcm_bps = bps; 510 dpcm->pcm_salign = salign; 511 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 512 513 mutex_lock(&dpcm->loopback->cable_lock); 514 if (!(cable->valid & ~(1 << substream->stream)) || 515 (get_setup(dpcm)->notify && 516 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 517 params_change(substream); 518 cable->valid |= 1 << substream->stream; 519 mutex_unlock(&dpcm->loopback->cable_lock); 520 521 return 0; 522} 523 524static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 525{ 526 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 527 char *dst = runtime->dma_area; 528 unsigned int dst_off = dpcm->buf_pos; 529 530 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 531 return; 532 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 533 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 534 535 for (;;) { 536 unsigned int size = bytes; 537 if (dst_off + size > dpcm->pcm_buffer_size) 538 size = dpcm->pcm_buffer_size - dst_off; 539 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 540 bytes_to_frames(runtime, size) * 541 runtime->channels); 542 dpcm->silent_size += size; 543 bytes -= size; 544 if (!bytes) 545 break; 546 dst_off = 0; 547 } 548} 549 550static void copy_play_buf_part_n(struct loopback_pcm *play, struct loopback_pcm *capt, 551 unsigned int size, unsigned int src_off, unsigned int dst_off) 552{ 553 unsigned int channels = capt->substream->runtime->channels; 554 unsigned int size_p_ch = size / channels; 555 unsigned int src_off_ch = src_off / channels; 556 unsigned int dst_off_ch = dst_off / channels; 557 int i; 558 559 for (i = 0; i < channels; i++) { 560 memcpy(capt->substream->runtime->dma_area + capt->channel_buf_n * i + dst_off_ch, 561 play->substream->runtime->dma_area + play->channel_buf_n * i + src_off_ch, 562 size_p_ch); 563 } 564} 565 566static void copy_play_buf(struct loopback_pcm *play, 567 struct loopback_pcm *capt, 568 unsigned int bytes) 569{ 570 struct snd_pcm_runtime *runtime = play->substream->runtime; 571 char *src = runtime->dma_area; 572 char *dst = capt->substream->runtime->dma_area; 573 unsigned int src_off = play->buf_pos; 574 unsigned int dst_off = capt->buf_pos; 575 unsigned int clear_bytes = 0; 576 577 /* check if playback is draining, trim the capture copy size 578 * when our pointer is at the end of playback ring buffer */ 579 if (runtime->state == SNDRV_PCM_STATE_DRAINING && 580 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 581 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 582 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 583 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 584 appl_ptr1 += play->buf_pos / play->pcm_salign; 585 if (appl_ptr < appl_ptr1) 586 appl_ptr1 -= runtime->buffer_size; 587 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 588 if (diff < bytes) { 589 clear_bytes = bytes - diff; 590 bytes = diff; 591 } 592 } 593 594 for (;;) { 595 unsigned int size = bytes; 596 if (src_off + size > play->pcm_buffer_size) 597 size = play->pcm_buffer_size - src_off; 598 if (dst_off + size > capt->pcm_buffer_size) 599 size = capt->pcm_buffer_size - dst_off; 600 if (!is_access_interleaved(runtime->access)) 601 copy_play_buf_part_n(play, capt, size, src_off, dst_off); 602 else 603 memcpy(dst + dst_off, src + src_off, size); 604 capt->silent_size = 0; 605 bytes -= size; 606 if (!bytes) 607 break; 608 src_off = (src_off + size) % play->pcm_buffer_size; 609 dst_off = (dst_off + size) % capt->pcm_buffer_size; 610 } 611 612 if (clear_bytes > 0) { 613 clear_capture_buf(capt, clear_bytes); 614 capt->silent_size = 0; 615 } 616} 617 618static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 619 unsigned int jiffies_delta) 620{ 621 unsigned long last_pos; 622 unsigned int delta; 623 624 last_pos = byte_pos(dpcm, dpcm->irq_pos); 625 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 626 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 627 if (delta >= dpcm->last_drift) 628 delta -= dpcm->last_drift; 629 dpcm->last_drift = 0; 630 if (dpcm->irq_pos >= dpcm->period_size_frac) { 631 dpcm->irq_pos %= dpcm->period_size_frac; 632 dpcm->period_update_pending = 1; 633 } 634 return delta; 635} 636 637static inline void bytepos_finish(struct loopback_pcm *dpcm, 638 unsigned int delta) 639{ 640 dpcm->buf_pos += delta; 641 dpcm->buf_pos %= dpcm->pcm_buffer_size; 642} 643 644/* call in cable->lock */ 645static unsigned int loopback_jiffies_timer_pos_update 646 (struct loopback_cable *cable) 647{ 648 struct loopback_pcm *dpcm_play = 649 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 650 struct loopback_pcm *dpcm_capt = 651 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 652 unsigned long delta_play = 0, delta_capt = 0, cur_jiffies; 653 unsigned int running, count1, count2; 654 655 cur_jiffies = jiffies; 656 running = cable->running ^ cable->pause; 657 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 658 delta_play = cur_jiffies - dpcm_play->last_jiffies; 659 dpcm_play->last_jiffies += delta_play; 660 } 661 662 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 663 delta_capt = cur_jiffies - dpcm_capt->last_jiffies; 664 dpcm_capt->last_jiffies += delta_capt; 665 } 666 667 if (delta_play == 0 && delta_capt == 0) 668 goto unlock; 669 670 if (delta_play > delta_capt) { 671 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 672 bytepos_finish(dpcm_play, count1); 673 delta_play = delta_capt; 674 } else if (delta_play < delta_capt) { 675 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 676 clear_capture_buf(dpcm_capt, count1); 677 bytepos_finish(dpcm_capt, count1); 678 delta_capt = delta_play; 679 } 680 681 if (delta_play == 0 && delta_capt == 0) 682 goto unlock; 683 684 /* note delta_capt == delta_play at this moment */ 685 count1 = bytepos_delta(dpcm_play, delta_play); 686 count2 = bytepos_delta(dpcm_capt, delta_capt); 687 if (count1 < count2) { 688 dpcm_capt->last_drift = count2 - count1; 689 count1 = count2; 690 } else if (count1 > count2) { 691 dpcm_play->last_drift = count1 - count2; 692 } 693 copy_play_buf(dpcm_play, dpcm_capt, count1); 694 bytepos_finish(dpcm_play, count1); 695 bytepos_finish(dpcm_capt, count1); 696 unlock: 697 return running; 698} 699 700static void loopback_jiffies_timer_function(struct timer_list *t) 701{ 702 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer); 703 unsigned long flags; 704 705 spin_lock_irqsave(&dpcm->cable->lock, flags); 706 if (loopback_jiffies_timer_pos_update(dpcm->cable) & 707 (1 << dpcm->substream->stream)) { 708 loopback_jiffies_timer_start(dpcm); 709 if (dpcm->period_update_pending) { 710 dpcm->period_update_pending = 0; 711 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 712 /* need to unlock before calling below */ 713 snd_pcm_period_elapsed(dpcm->substream); 714 return; 715 } 716 } 717 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 718} 719 720/* call in cable->lock */ 721static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime, 722 unsigned long resolution) 723{ 724 if (resolution != runtime->timer_resolution) { 725 struct loopback_pcm *dpcm = runtime->private_data; 726 struct loopback_cable *cable = dpcm->cable; 727 /* Worst case estimation of possible values for resolution 728 * resolution <= (512 * 1024) frames / 8kHz in nsec 729 * resolution <= 65.536.000.000 nsec 730 * 731 * period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz + 732 * 500.000 733 * period_size <= 12.582.912.000.000 <64bit 734 * / 1.000.000 usec/sec 735 */ 736 snd_pcm_uframes_t period_size_usec = 737 resolution / 1000 * runtime->rate; 738 /* round to nearest sample rate */ 739 snd_pcm_uframes_t period_size = 740 (period_size_usec + 500 * 1000) / (1000 * 1000); 741 742 pcm_err(dpcm->substream->pcm, 743 "Period size (%lu frames) of loopback device is not corresponding to timer resolution (%lu nsec = %lu frames) of card timer %d,%d,%d. Use period size of %lu frames for loopback device.", 744 runtime->period_size, resolution, period_size, 745 cable->snd_timer.id.card, 746 cable->snd_timer.id.device, 747 cable->snd_timer.id.subdevice, 748 period_size); 749 return -EINVAL; 750 } 751 return 0; 752} 753 754static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable, 755 int event, 756 unsigned long resolution) 757{ 758 struct loopback_pcm *dpcm_play, *dpcm_capt; 759 struct snd_pcm_substream *substream_play, *substream_capt; 760 struct snd_pcm_runtime *valid_runtime; 761 unsigned int running, elapsed_bytes; 762 unsigned long flags; 763 764 spin_lock_irqsave(&cable->lock, flags); 765 running = cable->running ^ cable->pause; 766 /* no need to do anything if no stream is running */ 767 if (!running) { 768 spin_unlock_irqrestore(&cable->lock, flags); 769 return; 770 } 771 772 dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 773 dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 774 775 if (event == SNDRV_TIMER_EVENT_MSTOP) { 776 if (!dpcm_play || 777 dpcm_play->substream->runtime->state != 778 SNDRV_PCM_STATE_DRAINING) { 779 spin_unlock_irqrestore(&cable->lock, flags); 780 return; 781 } 782 } 783 784 substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 785 dpcm_play->substream : NULL; 786 substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ? 787 dpcm_capt->substream : NULL; 788 valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 789 dpcm_play->substream->runtime : 790 dpcm_capt->substream->runtime; 791 792 /* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */ 793 if (event == SNDRV_TIMER_EVENT_TICK) { 794 /* The hardware rules guarantee that playback and capture period 795 * are the same. Therefore only one device has to be checked 796 * here. 797 */ 798 if (loopback_snd_timer_check_resolution(valid_runtime, 799 resolution) < 0) { 800 spin_unlock_irqrestore(&cable->lock, flags); 801 if (substream_play) 802 snd_pcm_stop_xrun(substream_play); 803 if (substream_capt) 804 snd_pcm_stop_xrun(substream_capt); 805 return; 806 } 807 } 808 809 elapsed_bytes = frames_to_bytes(valid_runtime, 810 valid_runtime->period_size); 811 /* The same timer interrupt is used for playback and capture device */ 812 if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) && 813 (running & (1 << SNDRV_PCM_STREAM_CAPTURE))) { 814 copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes); 815 bytepos_finish(dpcm_play, elapsed_bytes); 816 bytepos_finish(dpcm_capt, elapsed_bytes); 817 } else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 818 bytepos_finish(dpcm_play, elapsed_bytes); 819 } else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 820 clear_capture_buf(dpcm_capt, elapsed_bytes); 821 bytepos_finish(dpcm_capt, elapsed_bytes); 822 } 823 spin_unlock_irqrestore(&cable->lock, flags); 824 825 if (substream_play) 826 snd_pcm_period_elapsed(substream_play); 827 if (substream_capt) 828 snd_pcm_period_elapsed(substream_capt); 829} 830 831static void loopback_snd_timer_function(struct snd_timer_instance *timeri, 832 unsigned long resolution, 833 unsigned long ticks) 834{ 835 struct loopback_cable *cable = timeri->callback_data; 836 837 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK, 838 resolution); 839} 840 841static void loopback_snd_timer_work(struct work_struct *work) 842{ 843 struct loopback_cable *cable; 844 845 cable = container_of(work, struct loopback_cable, snd_timer.event_work); 846 loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0); 847} 848 849static void loopback_snd_timer_event(struct snd_timer_instance *timeri, 850 int event, 851 struct timespec64 *tstamp, 852 unsigned long resolution) 853{ 854 /* Do not lock cable->lock here because timer->lock is already hold. 855 * There are other functions which first lock cable->lock and than 856 * timer->lock e.g. 857 * loopback_trigger() 858 * spin_lock(&cable->lock) 859 * loopback_snd_timer_start() 860 * snd_timer_start() 861 * spin_lock(&timer->lock) 862 * Therefore when using the oposit order of locks here it could result 863 * in a deadlock. 864 */ 865 866 if (event == SNDRV_TIMER_EVENT_MSTOP) { 867 struct loopback_cable *cable = timeri->callback_data; 868 869 /* sound card of the timer was stopped. Therefore there will not 870 * be any further timer callbacks. Due to this forward audio 871 * data from here if in draining state. When still in running 872 * state the streaming will be aborted by the usual timeout. It 873 * should not be aborted here because may be the timer sound 874 * card does only a recovery and the timer is back soon. 875 * This work triggers loopback_snd_timer_work() 876 */ 877 schedule_work(&cable->snd_timer.event_work); 878 } 879} 880 881static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm, 882 struct snd_info_buffer *buffer) 883{ 884 snd_iprintf(buffer, " update_pending:\t%u\n", 885 dpcm->period_update_pending); 886 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 887 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 888 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 889 dpcm->last_jiffies, jiffies); 890 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 891} 892 893static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm, 894 struct snd_info_buffer *buffer) 895{ 896 struct loopback_cable *cable = dpcm->cable; 897 898 snd_iprintf(buffer, " sound timer:\thw:%d,%d,%d\n", 899 cable->snd_timer.id.card, 900 cable->snd_timer.id.device, 901 cable->snd_timer.id.subdevice); 902 snd_iprintf(buffer, " timer open:\t\t%s\n", 903 (cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ? 904 "capture" : "playback"); 905} 906 907static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 908{ 909 struct snd_pcm_runtime *runtime = substream->runtime; 910 struct loopback_pcm *dpcm = runtime->private_data; 911 snd_pcm_uframes_t pos; 912 913 spin_lock(&dpcm->cable->lock); 914 if (dpcm->cable->ops->pos_update) 915 dpcm->cable->ops->pos_update(dpcm->cable); 916 pos = dpcm->buf_pos; 917 spin_unlock(&dpcm->cable->lock); 918 return bytes_to_frames(runtime, pos); 919} 920 921static const struct snd_pcm_hardware loopback_pcm_hardware = 922{ 923 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 924 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 925 SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_NONINTERLEAVED), 926 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 927 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE | 928 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | 929 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 930 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 931 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 932 .rate_min = 8000, 933 .rate_max = 192000, 934 .channels_min = 1, 935 .channels_max = 32, 936 .buffer_bytes_max = 2 * 1024 * 1024, 937 .period_bytes_min = 64, 938 /* note check overflow in frac_pos() using pcm_rate_shift before 939 changing period_bytes_max value */ 940 .period_bytes_max = 1024 * 1024, 941 .periods_min = 1, 942 .periods_max = 1024, 943 .fifo_size = 0, 944}; 945 946static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 947{ 948 struct loopback_pcm *dpcm = runtime->private_data; 949 kfree(dpcm); 950} 951 952static int loopback_hw_free(struct snd_pcm_substream *substream) 953{ 954 struct snd_pcm_runtime *runtime = substream->runtime; 955 struct loopback_pcm *dpcm = runtime->private_data; 956 struct loopback_cable *cable = dpcm->cable; 957 958 mutex_lock(&dpcm->loopback->cable_lock); 959 cable->valid &= ~(1 << substream->stream); 960 mutex_unlock(&dpcm->loopback->cable_lock); 961 return 0; 962} 963 964static unsigned int get_cable_index(struct snd_pcm_substream *substream) 965{ 966 if (!substream->pcm->device) 967 return substream->stream; 968 else 969 return !substream->stream; 970} 971 972static int rule_format(struct snd_pcm_hw_params *params, 973 struct snd_pcm_hw_rule *rule) 974{ 975 struct loopback_pcm *dpcm = rule->private; 976 struct loopback_cable *cable = dpcm->cable; 977 struct snd_mask m; 978 979 snd_mask_none(&m); 980 mutex_lock(&dpcm->loopback->cable_lock); 981 m.bits[0] = (u_int32_t)cable->hw.formats; 982 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32); 983 mutex_unlock(&dpcm->loopback->cable_lock); 984 return snd_mask_refine(hw_param_mask(params, rule->var), &m); 985} 986 987static int rule_rate(struct snd_pcm_hw_params *params, 988 struct snd_pcm_hw_rule *rule) 989{ 990 struct loopback_pcm *dpcm = rule->private; 991 struct loopback_cable *cable = dpcm->cable; 992 struct snd_interval t; 993 994 mutex_lock(&dpcm->loopback->cable_lock); 995 t.min = cable->hw.rate_min; 996 t.max = cable->hw.rate_max; 997 mutex_unlock(&dpcm->loopback->cable_lock); 998 t.openmin = t.openmax = 0; 999 t.integer = 0; 1000 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 1001} 1002 1003static int rule_channels(struct snd_pcm_hw_params *params, 1004 struct snd_pcm_hw_rule *rule) 1005{ 1006 struct loopback_pcm *dpcm = rule->private; 1007 struct loopback_cable *cable = dpcm->cable; 1008 struct snd_interval t; 1009 1010 mutex_lock(&dpcm->loopback->cable_lock); 1011 t.min = cable->hw.channels_min; 1012 t.max = cable->hw.channels_max; 1013 mutex_unlock(&dpcm->loopback->cable_lock); 1014 t.openmin = t.openmax = 0; 1015 t.integer = 0; 1016 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 1017} 1018 1019static int rule_period_bytes(struct snd_pcm_hw_params *params, 1020 struct snd_pcm_hw_rule *rule) 1021{ 1022 struct loopback_pcm *dpcm = rule->private; 1023 struct loopback_cable *cable = dpcm->cable; 1024 struct snd_interval t; 1025 1026 mutex_lock(&dpcm->loopback->cable_lock); 1027 t.min = cable->hw.period_bytes_min; 1028 t.max = cable->hw.period_bytes_max; 1029 mutex_unlock(&dpcm->loopback->cable_lock); 1030 t.openmin = 0; 1031 t.openmax = 0; 1032 t.integer = 0; 1033 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 1034} 1035 1036static void free_cable(struct snd_pcm_substream *substream) 1037{ 1038 struct loopback *loopback = substream->private_data; 1039 int dev = get_cable_index(substream); 1040 struct loopback_cable *cable; 1041 1042 cable = loopback->cables[substream->number][dev]; 1043 if (!cable) 1044 return; 1045 if (cable->streams[!substream->stream]) { 1046 /* other stream is still alive */ 1047 spin_lock_irq(&cable->lock); 1048 cable->streams[substream->stream] = NULL; 1049 spin_unlock_irq(&cable->lock); 1050 } else { 1051 struct loopback_pcm *dpcm = substream->runtime->private_data; 1052 1053 if (cable->ops && cable->ops->close_cable && dpcm) 1054 cable->ops->close_cable(dpcm); 1055 /* free the cable */ 1056 loopback->cables[substream->number][dev] = NULL; 1057 kfree(cable); 1058 } 1059} 1060 1061static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm) 1062{ 1063 timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0); 1064 1065 return 0; 1066} 1067 1068static const struct loopback_ops loopback_jiffies_timer_ops = { 1069 .open = loopback_jiffies_timer_open, 1070 .start = loopback_jiffies_timer_start, 1071 .stop = loopback_jiffies_timer_stop, 1072 .stop_sync = loopback_jiffies_timer_stop_sync, 1073 .close_substream = loopback_jiffies_timer_stop_sync, 1074 .pos_update = loopback_jiffies_timer_pos_update, 1075 .dpcm_info = loopback_jiffies_timer_dpcm_info, 1076}; 1077 1078static int loopback_parse_timer_id(const char *str, 1079 struct snd_timer_id *tid) 1080{ 1081 /* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */ 1082 const char * const sep_dev = ".,"; 1083 const char * const sep_pref = ":"; 1084 const char *name = str; 1085 char *sep, save = '\0'; 1086 int card_idx = 0, dev = 0, subdev = 0; 1087 int err; 1088 1089 sep = strpbrk(str, sep_pref); 1090 if (sep) 1091 name = sep + 1; 1092 sep = strpbrk(name, sep_dev); 1093 if (sep) { 1094 save = *sep; 1095 *sep = '\0'; 1096 } 1097 err = kstrtoint(name, 0, &card_idx); 1098 if (err == -EINVAL) { 1099 /* Must be the name, not number */ 1100 for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) { 1101 struct snd_card *card = snd_card_ref(card_idx); 1102 1103 if (card) { 1104 if (!strcmp(card->id, name)) 1105 err = 0; 1106 snd_card_unref(card); 1107 } 1108 if (!err) 1109 break; 1110 } 1111 } 1112 if (sep) { 1113 *sep = save; 1114 if (!err) { 1115 char *sep2, save2 = '\0'; 1116 1117 sep2 = strpbrk(sep + 1, sep_dev); 1118 if (sep2) { 1119 save2 = *sep2; 1120 *sep2 = '\0'; 1121 } 1122 err = kstrtoint(sep + 1, 0, &dev); 1123 if (sep2) { 1124 *sep2 = save2; 1125 if (!err) 1126 err = kstrtoint(sep2 + 1, 0, &subdev); 1127 } 1128 } 1129 } 1130 if (!err && tid) { 1131 tid->card = card_idx; 1132 tid->device = dev; 1133 tid->subdevice = subdev; 1134 } 1135 return err; 1136} 1137 1138/* call in loopback->cable_lock */ 1139static int loopback_snd_timer_open(struct loopback_pcm *dpcm) 1140{ 1141 int err = 0; 1142 struct snd_timer_id tid = { 1143 .dev_class = SNDRV_TIMER_CLASS_PCM, 1144 .dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION, 1145 }; 1146 struct snd_timer_instance *timeri; 1147 struct loopback_cable *cable = dpcm->cable; 1148 1149 /* check if timer was already opened. It is only opened once 1150 * per playback and capture subdevice (aka cable). 1151 */ 1152 if (cable->snd_timer.instance) 1153 goto exit; 1154 1155 err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid); 1156 if (err < 0) { 1157 pcm_err(dpcm->substream->pcm, 1158 "Parsing timer source \'%s\' failed with %d", 1159 dpcm->loopback->timer_source, err); 1160 goto exit; 1161 } 1162 1163 cable->snd_timer.stream = dpcm->substream->stream; 1164 cable->snd_timer.id = tid; 1165 1166 timeri = snd_timer_instance_new(dpcm->loopback->card->id); 1167 if (!timeri) { 1168 err = -ENOMEM; 1169 goto exit; 1170 } 1171 /* The callback has to be called from another work. If 1172 * SNDRV_TIMER_IFLG_FAST is specified it will be called from the 1173 * snd_pcm_period_elapsed() call of the selected sound card. 1174 * snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave(). 1175 * Due to our callback loopback_snd_timer_function() also calls 1176 * snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave(). 1177 * This would end up in a dead lock. 1178 */ 1179 timeri->flags |= SNDRV_TIMER_IFLG_AUTO; 1180 timeri->callback = loopback_snd_timer_function; 1181 timeri->callback_data = (void *)cable; 1182 timeri->ccallback = loopback_snd_timer_event; 1183 1184 /* initialise a work used for draining */ 1185 INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work); 1186 1187 /* The mutex loopback->cable_lock is kept locked. 1188 * Therefore snd_timer_open() cannot be called a second time 1189 * by the other device of the same cable. 1190 * Therefore the following issue cannot happen: 1191 * [proc1] Call loopback_timer_open() -> 1192 * Unlock cable->lock for snd_timer_close/open() call 1193 * [proc2] Call loopback_timer_open() -> snd_timer_open(), 1194 * snd_timer_start() 1195 * [proc1] Call snd_timer_open() and overwrite running timer 1196 * instance 1197 */ 1198 err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid); 1199 if (err < 0) { 1200 pcm_err(dpcm->substream->pcm, 1201 "snd_timer_open (%d,%d,%d) failed with %d", 1202 cable->snd_timer.id.card, 1203 cable->snd_timer.id.device, 1204 cable->snd_timer.id.subdevice, 1205 err); 1206 snd_timer_instance_free(timeri); 1207 goto exit; 1208 } 1209 1210 cable->snd_timer.instance = timeri; 1211 1212exit: 1213 return err; 1214} 1215 1216/* stop_sync() is not required for sound timer because it does not need to be 1217 * restarted in loopback_prepare() on Xrun recovery 1218 */ 1219static const struct loopback_ops loopback_snd_timer_ops = { 1220 .open = loopback_snd_timer_open, 1221 .start = loopback_snd_timer_start, 1222 .stop = loopback_snd_timer_stop, 1223 .close_cable = loopback_snd_timer_close_cable, 1224 .dpcm_info = loopback_snd_timer_dpcm_info, 1225}; 1226 1227static int loopback_open(struct snd_pcm_substream *substream) 1228{ 1229 struct snd_pcm_runtime *runtime = substream->runtime; 1230 struct loopback *loopback = substream->private_data; 1231 struct loopback_pcm *dpcm; 1232 struct loopback_cable *cable = NULL; 1233 int err = 0; 1234 int dev = get_cable_index(substream); 1235 1236 mutex_lock(&loopback->cable_lock); 1237 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 1238 if (!dpcm) { 1239 err = -ENOMEM; 1240 goto unlock; 1241 } 1242 dpcm->loopback = loopback; 1243 dpcm->substream = substream; 1244 1245 cable = loopback->cables[substream->number][dev]; 1246 if (!cable) { 1247 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 1248 if (!cable) { 1249 err = -ENOMEM; 1250 goto unlock; 1251 } 1252 spin_lock_init(&cable->lock); 1253 cable->hw = loopback_pcm_hardware; 1254 if (loopback->timer_source) 1255 cable->ops = &loopback_snd_timer_ops; 1256 else 1257 cable->ops = &loopback_jiffies_timer_ops; 1258 loopback->cables[substream->number][dev] = cable; 1259 } 1260 dpcm->cable = cable; 1261 runtime->private_data = dpcm; 1262 1263 if (cable->ops->open) { 1264 err = cable->ops->open(dpcm); 1265 if (err < 0) 1266 goto unlock; 1267 } 1268 1269 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 1270 1271 /* use dynamic rules based on actual runtime->hw values */ 1272 /* note that the default rules created in the PCM midlevel code */ 1273 /* are cached -> they do not reflect the actual state */ 1274 err = snd_pcm_hw_rule_add(runtime, 0, 1275 SNDRV_PCM_HW_PARAM_FORMAT, 1276 rule_format, dpcm, 1277 SNDRV_PCM_HW_PARAM_FORMAT, -1); 1278 if (err < 0) 1279 goto unlock; 1280 err = snd_pcm_hw_rule_add(runtime, 0, 1281 SNDRV_PCM_HW_PARAM_RATE, 1282 rule_rate, dpcm, 1283 SNDRV_PCM_HW_PARAM_RATE, -1); 1284 if (err < 0) 1285 goto unlock; 1286 err = snd_pcm_hw_rule_add(runtime, 0, 1287 SNDRV_PCM_HW_PARAM_CHANNELS, 1288 rule_channels, dpcm, 1289 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 1290 if (err < 0) 1291 goto unlock; 1292 1293 /* In case of sound timer the period time of both devices of the same 1294 * loop has to be the same. 1295 * This rule only takes effect if a sound timer was chosen 1296 */ 1297 if (cable->snd_timer.instance) { 1298 err = snd_pcm_hw_rule_add(runtime, 0, 1299 SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 1300 rule_period_bytes, dpcm, 1301 SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1); 1302 if (err < 0) 1303 goto unlock; 1304 } 1305 1306 /* loopback_runtime_free() has not to be called if kfree(dpcm) was 1307 * already called here. Otherwise it will end up with a double free. 1308 */ 1309 runtime->private_free = loopback_runtime_free; 1310 if (get_notify(dpcm)) 1311 runtime->hw = loopback_pcm_hardware; 1312 else 1313 runtime->hw = cable->hw; 1314 1315 spin_lock_irq(&cable->lock); 1316 cable->streams[substream->stream] = dpcm; 1317 spin_unlock_irq(&cable->lock); 1318 1319 unlock: 1320 if (err < 0) { 1321 free_cable(substream); 1322 kfree(dpcm); 1323 } 1324 mutex_unlock(&loopback->cable_lock); 1325 return err; 1326} 1327 1328static int loopback_close(struct snd_pcm_substream *substream) 1329{ 1330 struct loopback *loopback = substream->private_data; 1331 struct loopback_pcm *dpcm = substream->runtime->private_data; 1332 int err = 0; 1333 1334 if (dpcm->cable->ops->close_substream) 1335 err = dpcm->cable->ops->close_substream(dpcm); 1336 mutex_lock(&loopback->cable_lock); 1337 free_cable(substream); 1338 mutex_unlock(&loopback->cable_lock); 1339 return err; 1340} 1341 1342static const struct snd_pcm_ops loopback_pcm_ops = { 1343 .open = loopback_open, 1344 .close = loopback_close, 1345 .hw_free = loopback_hw_free, 1346 .prepare = loopback_prepare, 1347 .trigger = loopback_trigger, 1348 .pointer = loopback_pointer, 1349}; 1350 1351static int loopback_pcm_new(struct loopback *loopback, 1352 int device, int substreams) 1353{ 1354 struct snd_pcm *pcm; 1355 int err; 1356 1357 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 1358 substreams, substreams, &pcm); 1359 if (err < 0) 1360 return err; 1361 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops); 1362 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops); 1363 snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0); 1364 1365 pcm->private_data = loopback; 1366 pcm->info_flags = 0; 1367 strcpy(pcm->name, "Loopback PCM"); 1368 1369 loopback->pcm[device] = pcm; 1370 return 0; 1371} 1372 1373static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 1374 struct snd_ctl_elem_info *uinfo) 1375{ 1376 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 1377 uinfo->count = 1; 1378 uinfo->value.integer.min = 80000; 1379 uinfo->value.integer.max = 120000; 1380 uinfo->value.integer.step = 1; 1381 return 0; 1382} 1383 1384static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 1385 struct snd_ctl_elem_value *ucontrol) 1386{ 1387 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1388 1389 mutex_lock(&loopback->cable_lock); 1390 ucontrol->value.integer.value[0] = 1391 loopback->setup[kcontrol->id.subdevice] 1392 [kcontrol->id.device].rate_shift; 1393 mutex_unlock(&loopback->cable_lock); 1394 return 0; 1395} 1396 1397static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 1398 struct snd_ctl_elem_value *ucontrol) 1399{ 1400 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1401 unsigned int val; 1402 int change = 0; 1403 1404 val = ucontrol->value.integer.value[0]; 1405 if (val < 80000) 1406 val = 80000; 1407 if (val > 120000) 1408 val = 120000; 1409 mutex_lock(&loopback->cable_lock); 1410 if (val != loopback->setup[kcontrol->id.subdevice] 1411 [kcontrol->id.device].rate_shift) { 1412 loopback->setup[kcontrol->id.subdevice] 1413 [kcontrol->id.device].rate_shift = val; 1414 change = 1; 1415 } 1416 mutex_unlock(&loopback->cable_lock); 1417 return change; 1418} 1419 1420static int loopback_notify_get(struct snd_kcontrol *kcontrol, 1421 struct snd_ctl_elem_value *ucontrol) 1422{ 1423 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1424 1425 mutex_lock(&loopback->cable_lock); 1426 ucontrol->value.integer.value[0] = 1427 loopback->setup[kcontrol->id.subdevice] 1428 [kcontrol->id.device].notify; 1429 mutex_unlock(&loopback->cable_lock); 1430 return 0; 1431} 1432 1433static int loopback_notify_put(struct snd_kcontrol *kcontrol, 1434 struct snd_ctl_elem_value *ucontrol) 1435{ 1436 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1437 unsigned int val; 1438 int change = 0; 1439 1440 val = ucontrol->value.integer.value[0] ? 1 : 0; 1441 mutex_lock(&loopback->cable_lock); 1442 if (val != loopback->setup[kcontrol->id.subdevice] 1443 [kcontrol->id.device].notify) { 1444 loopback->setup[kcontrol->id.subdevice] 1445 [kcontrol->id.device].notify = val; 1446 change = 1; 1447 } 1448 mutex_unlock(&loopback->cable_lock); 1449 return change; 1450} 1451 1452static int loopback_active_get(struct snd_kcontrol *kcontrol, 1453 struct snd_ctl_elem_value *ucontrol) 1454{ 1455 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1456 struct loopback_cable *cable; 1457 1458 unsigned int val = 0; 1459 1460 mutex_lock(&loopback->cable_lock); 1461 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 1462 if (cable != NULL) { 1463 unsigned int running = cable->running ^ cable->pause; 1464 1465 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0; 1466 } 1467 mutex_unlock(&loopback->cable_lock); 1468 ucontrol->value.integer.value[0] = val; 1469 return 0; 1470} 1471 1472static int loopback_format_info(struct snd_kcontrol *kcontrol, 1473 struct snd_ctl_elem_info *uinfo) 1474{ 1475 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 1476 uinfo->count = 1; 1477 uinfo->value.integer.min = 0; 1478 uinfo->value.integer.max = (__force int)SNDRV_PCM_FORMAT_LAST; 1479 uinfo->value.integer.step = 1; 1480 return 0; 1481} 1482 1483static int loopback_format_get(struct snd_kcontrol *kcontrol, 1484 struct snd_ctl_elem_value *ucontrol) 1485{ 1486 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1487 1488 ucontrol->value.integer.value[0] = 1489 (__force int)loopback->setup[kcontrol->id.subdevice] 1490 [kcontrol->id.device].format; 1491 return 0; 1492} 1493 1494static int loopback_rate_info(struct snd_kcontrol *kcontrol, 1495 struct snd_ctl_elem_info *uinfo) 1496{ 1497 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 1498 uinfo->count = 1; 1499 uinfo->value.integer.min = 0; 1500 uinfo->value.integer.max = 192000; 1501 uinfo->value.integer.step = 1; 1502 return 0; 1503} 1504 1505static int loopback_rate_get(struct snd_kcontrol *kcontrol, 1506 struct snd_ctl_elem_value *ucontrol) 1507{ 1508 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1509 1510 mutex_lock(&loopback->cable_lock); 1511 ucontrol->value.integer.value[0] = 1512 loopback->setup[kcontrol->id.subdevice] 1513 [kcontrol->id.device].rate; 1514 mutex_unlock(&loopback->cable_lock); 1515 return 0; 1516} 1517 1518static int loopback_channels_info(struct snd_kcontrol *kcontrol, 1519 struct snd_ctl_elem_info *uinfo) 1520{ 1521 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 1522 uinfo->count = 1; 1523 uinfo->value.integer.min = 1; 1524 uinfo->value.integer.max = 1024; 1525 uinfo->value.integer.step = 1; 1526 return 0; 1527} 1528 1529static int loopback_channels_get(struct snd_kcontrol *kcontrol, 1530 struct snd_ctl_elem_value *ucontrol) 1531{ 1532 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1533 1534 mutex_lock(&loopback->cable_lock); 1535 ucontrol->value.integer.value[0] = 1536 loopback->setup[kcontrol->id.subdevice] 1537 [kcontrol->id.device].channels; 1538 mutex_unlock(&loopback->cable_lock); 1539 return 0; 1540} 1541 1542static int loopback_access_info(struct snd_kcontrol *kcontrol, 1543 struct snd_ctl_elem_info *uinfo) 1544{ 1545 const char * const texts[] = {"Interleaved", "Non-interleaved"}; 1546 1547 return snd_ctl_enum_info(uinfo, 1, ARRAY_SIZE(texts), texts); 1548} 1549 1550static int loopback_access_get(struct snd_kcontrol *kcontrol, 1551 struct snd_ctl_elem_value *ucontrol) 1552{ 1553 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 1554 snd_pcm_access_t access; 1555 1556 mutex_lock(&loopback->cable_lock); 1557 access = loopback->setup[kcontrol->id.subdevice][kcontrol->id.device].access; 1558 1559 ucontrol->value.enumerated.item[0] = !is_access_interleaved(access); 1560 1561 mutex_unlock(&loopback->cable_lock); 1562 return 0; 1563} 1564 1565static const struct snd_kcontrol_new loopback_controls[] = { 1566{ 1567 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1568 .name = "PCM Rate Shift 100000", 1569 .info = loopback_rate_shift_info, 1570 .get = loopback_rate_shift_get, 1571 .put = loopback_rate_shift_put, 1572}, 1573{ 1574 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1575 .name = "PCM Notify", 1576 .info = snd_ctl_boolean_mono_info, 1577 .get = loopback_notify_get, 1578 .put = loopback_notify_put, 1579}, 1580#define ACTIVE_IDX 2 1581{ 1582 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1583 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1584 .name = "PCM Slave Active", 1585 .info = snd_ctl_boolean_mono_info, 1586 .get = loopback_active_get, 1587}, 1588#define FORMAT_IDX 3 1589{ 1590 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1591 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1592 .name = "PCM Slave Format", 1593 .info = loopback_format_info, 1594 .get = loopback_format_get 1595}, 1596#define RATE_IDX 4 1597{ 1598 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1599 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1600 .name = "PCM Slave Rate", 1601 .info = loopback_rate_info, 1602 .get = loopback_rate_get 1603}, 1604#define CHANNELS_IDX 5 1605{ 1606 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1607 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1608 .name = "PCM Slave Channels", 1609 .info = loopback_channels_info, 1610 .get = loopback_channels_get 1611}, 1612#define ACCESS_IDX 6 1613{ 1614 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1615 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1616 .name = "PCM Slave Access Mode", 1617 .info = loopback_access_info, 1618 .get = loopback_access_get, 1619}, 1620}; 1621 1622static int loopback_mixer_new(struct loopback *loopback, int notify) 1623{ 1624 struct snd_card *card = loopback->card; 1625 struct snd_pcm *pcm; 1626 struct snd_kcontrol *kctl; 1627 struct loopback_setup *setup; 1628 int err, dev, substr, substr_count, idx; 1629 1630 strcpy(card->mixername, "Loopback Mixer"); 1631 for (dev = 0; dev < 2; dev++) { 1632 pcm = loopback->pcm[dev]; 1633 substr_count = 1634 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1635 for (substr = 0; substr < substr_count; substr++) { 1636 setup = &loopback->setup[substr][dev]; 1637 setup->notify = notify; 1638 setup->rate_shift = NO_PITCH; 1639 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1640 setup->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED; 1641 setup->rate = 48000; 1642 setup->channels = 2; 1643 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1644 idx++) { 1645 kctl = snd_ctl_new1(&loopback_controls[idx], 1646 loopback); 1647 if (!kctl) 1648 return -ENOMEM; 1649 kctl->id.device = dev; 1650 kctl->id.subdevice = substr; 1651 1652 /* Add the control before copying the id so that 1653 * the numid field of the id is set in the copy. 1654 */ 1655 err = snd_ctl_add(card, kctl); 1656 if (err < 0) 1657 return err; 1658 1659 switch (idx) { 1660 case ACTIVE_IDX: 1661 setup->active_id = kctl->id; 1662 break; 1663 case FORMAT_IDX: 1664 setup->format_id = kctl->id; 1665 break; 1666 case RATE_IDX: 1667 setup->rate_id = kctl->id; 1668 break; 1669 case CHANNELS_IDX: 1670 setup->channels_id = kctl->id; 1671 break; 1672 case ACCESS_IDX: 1673 setup->access_id = kctl->id; 1674 break; 1675 default: 1676 break; 1677 } 1678 } 1679 } 1680 } 1681 return 0; 1682} 1683 1684static void print_dpcm_info(struct snd_info_buffer *buffer, 1685 struct loopback_pcm *dpcm, 1686 const char *id) 1687{ 1688 snd_iprintf(buffer, " %s\n", id); 1689 if (dpcm == NULL) { 1690 snd_iprintf(buffer, " inactive\n"); 1691 return; 1692 } 1693 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1694 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1695 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1696 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1697 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1698 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1699 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1700 if (dpcm->cable->ops->dpcm_info) 1701 dpcm->cable->ops->dpcm_info(dpcm, buffer); 1702} 1703 1704static void print_substream_info(struct snd_info_buffer *buffer, 1705 struct loopback *loopback, 1706 int sub, 1707 int num) 1708{ 1709 struct loopback_cable *cable = loopback->cables[sub][num]; 1710 1711 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1712 if (cable == NULL) { 1713 snd_iprintf(buffer, " inactive\n"); 1714 return; 1715 } 1716 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1717 snd_iprintf(buffer, " running: %u\n", cable->running); 1718 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1719 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1720 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1721} 1722 1723static void print_cable_info(struct snd_info_entry *entry, 1724 struct snd_info_buffer *buffer) 1725{ 1726 struct loopback *loopback = entry->private_data; 1727 int sub, num; 1728 1729 mutex_lock(&loopback->cable_lock); 1730 num = entry->name[strlen(entry->name)-1]; 1731 num = num == '0' ? 0 : 1; 1732 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1733 print_substream_info(buffer, loopback, sub, num); 1734 mutex_unlock(&loopback->cable_lock); 1735} 1736 1737static int loopback_cable_proc_new(struct loopback *loopback, int cidx) 1738{ 1739 char name[32]; 1740 1741 snprintf(name, sizeof(name), "cable#%d", cidx); 1742 return snd_card_ro_proc_new(loopback->card, name, loopback, 1743 print_cable_info); 1744} 1745 1746static void loopback_set_timer_source(struct loopback *loopback, 1747 const char *value) 1748{ 1749 if (loopback->timer_source) { 1750 devm_kfree(loopback->card->dev, loopback->timer_source); 1751 loopback->timer_source = NULL; 1752 } 1753 if (value && *value) 1754 loopback->timer_source = devm_kstrdup(loopback->card->dev, 1755 value, GFP_KERNEL); 1756} 1757 1758static void print_timer_source_info(struct snd_info_entry *entry, 1759 struct snd_info_buffer *buffer) 1760{ 1761 struct loopback *loopback = entry->private_data; 1762 1763 mutex_lock(&loopback->cable_lock); 1764 snd_iprintf(buffer, "%s\n", 1765 loopback->timer_source ? loopback->timer_source : ""); 1766 mutex_unlock(&loopback->cable_lock); 1767} 1768 1769static void change_timer_source_info(struct snd_info_entry *entry, 1770 struct snd_info_buffer *buffer) 1771{ 1772 struct loopback *loopback = entry->private_data; 1773 char line[64]; 1774 1775 mutex_lock(&loopback->cable_lock); 1776 if (!snd_info_get_line(buffer, line, sizeof(line))) 1777 loopback_set_timer_source(loopback, strim(line)); 1778 mutex_unlock(&loopback->cable_lock); 1779} 1780 1781static int loopback_timer_source_proc_new(struct loopback *loopback) 1782{ 1783 return snd_card_rw_proc_new(loopback->card, "timer_source", loopback, 1784 print_timer_source_info, 1785 change_timer_source_info); 1786} 1787 1788static int loopback_probe(struct platform_device *devptr) 1789{ 1790 struct snd_card *card; 1791 struct loopback *loopback; 1792 int dev = devptr->id; 1793 int err; 1794 1795 err = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE, 1796 sizeof(struct loopback), &card); 1797 if (err < 0) 1798 return err; 1799 loopback = card->private_data; 1800 1801 if (pcm_substreams[dev] < 1) 1802 pcm_substreams[dev] = 1; 1803 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1804 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1805 1806 loopback->card = card; 1807 loopback_set_timer_source(loopback, timer_source[dev]); 1808 1809 mutex_init(&loopback->cable_lock); 1810 1811 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1812 if (err < 0) 1813 return err; 1814 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1815 if (err < 0) 1816 return err; 1817 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1818 if (err < 0) 1819 return err; 1820 loopback_cable_proc_new(loopback, 0); 1821 loopback_cable_proc_new(loopback, 1); 1822 loopback_timer_source_proc_new(loopback); 1823 strcpy(card->driver, "Loopback"); 1824 strcpy(card->shortname, "Loopback"); 1825 sprintf(card->longname, "Loopback %i", dev + 1); 1826 err = snd_card_register(card); 1827 if (err < 0) 1828 return err; 1829 platform_set_drvdata(devptr, card); 1830 return 0; 1831} 1832 1833static int loopback_suspend(struct device *pdev) 1834{ 1835 struct snd_card *card = dev_get_drvdata(pdev); 1836 1837 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1838 return 0; 1839} 1840 1841static int loopback_resume(struct device *pdev) 1842{ 1843 struct snd_card *card = dev_get_drvdata(pdev); 1844 1845 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1846 return 0; 1847} 1848 1849static DEFINE_SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1850 1851#define SND_LOOPBACK_DRIVER "snd_aloop" 1852 1853static struct platform_driver loopback_driver = { 1854 .probe = loopback_probe, 1855 .driver = { 1856 .name = SND_LOOPBACK_DRIVER, 1857 .pm = &loopback_pm, 1858 }, 1859}; 1860 1861static void loopback_unregister_all(void) 1862{ 1863 int i; 1864 1865 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1866 platform_device_unregister(devices[i]); 1867 platform_driver_unregister(&loopback_driver); 1868} 1869 1870static int __init alsa_card_loopback_init(void) 1871{ 1872 int i, err, cards; 1873 1874 err = platform_driver_register(&loopback_driver); 1875 if (err < 0) 1876 return err; 1877 1878 1879 cards = 0; 1880 for (i = 0; i < SNDRV_CARDS; i++) { 1881 struct platform_device *device; 1882 if (!enable[i]) 1883 continue; 1884 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1885 i, NULL, 0); 1886 if (IS_ERR(device)) 1887 continue; 1888 if (!platform_get_drvdata(device)) { 1889 platform_device_unregister(device); 1890 continue; 1891 } 1892 devices[i] = device; 1893 cards++; 1894 } 1895 if (!cards) { 1896#ifdef MODULE 1897 printk(KERN_ERR "aloop: No loopback enabled\n"); 1898#endif 1899 loopback_unregister_all(); 1900 return -ENODEV; 1901 } 1902 return 0; 1903} 1904 1905static void __exit alsa_card_loopback_exit(void) 1906{ 1907 loopback_unregister_all(); 1908} 1909 1910module_init(alsa_card_loopback_init) 1911module_exit(alsa_card_loopback_exit) 1912