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 İnan <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 32 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 33 MODULE_DESCRIPTION("A loopback soundcard"); 34 MODULE_LICENSE("GPL"); 35 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 36 37 #define MAX_PCM_SUBSTREAMS 8 38 39 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 40 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 41 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 42 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 43 static int pcm_notify[SNDRV_CARDS]; 44 45 module_param_array(index, int, NULL, 0444); 46 MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 47 module_param_array(id, charp, NULL, 0444); 48 MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 49 module_param_array(enable, bool, NULL, 0444); 50 MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 51 module_param_array(pcm_substreams, int, NULL, 0444); 52 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 53 module_param_array(pcm_notify, int, NULL, 0444); 54 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 55 56 #define NO_PITCH 100000 57 58 struct loopback_pcm; 59 60 struct loopback_cable { 61 spinlock_t lock; 62 struct loopback_pcm *streams[2]; 63 struct snd_pcm_hardware hw; 64 /* flags */ 65 unsigned int valid; 66 unsigned int running; 67 unsigned int pause; 68 }; 69 70 struct loopback_setup { 71 unsigned int notify: 1; 72 unsigned int rate_shift; 73 unsigned int format; 74 unsigned int rate; 75 unsigned int channels; 76 struct snd_ctl_elem_id active_id; 77 struct snd_ctl_elem_id format_id; 78 struct snd_ctl_elem_id rate_id; 79 struct snd_ctl_elem_id channels_id; 80 }; 81 82 struct loopback { 83 struct snd_card *card; 84 struct mutex cable_lock; 85 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 86 struct snd_pcm *pcm[2]; 87 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 88 }; 89 90 struct loopback_pcm { 91 struct loopback *loopback; 92 struct snd_pcm_substream *substream; 93 struct loopback_cable *cable; 94 unsigned int pcm_buffer_size; 95 unsigned int buf_pos; /* position in buffer */ 96 unsigned int silent_size; 97 /* PCM parameters */ 98 unsigned int pcm_period_size; 99 unsigned int pcm_bps; /* bytes per second */ 100 unsigned int pcm_salign; /* bytes per sample * channels */ 101 unsigned int pcm_rate_shift; /* rate shift value */ 102 /* flags */ 103 unsigned int period_update_pending :1; 104 /* timer stuff */ 105 unsigned int irq_pos; /* fractional IRQ position */ 106 unsigned int period_size_frac; 107 unsigned int last_drift; 108 unsigned long last_jiffies; 109 struct timer_list timer; 110 }; 111 112 static struct platform_device *devices[SNDRV_CARDS]; 113 114 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 115 { 116 if (dpcm->pcm_rate_shift == NO_PITCH) { 117 x /= HZ; 118 } else { 119 x = div_u64(NO_PITCH * (unsigned long long)x, 120 HZ * (unsigned long long)dpcm->pcm_rate_shift); 121 } 122 return x - (x % dpcm->pcm_salign); 123 } 124 125 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 126 { 127 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 128 return x * HZ; 129 } else { 130 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 131 NO_PITCH); 132 } 133 return x; 134 } 135 136 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 137 { 138 int device = dpcm->substream->pstr->pcm->device; 139 140 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 141 device ^= 1; 142 return &dpcm->loopback->setup[dpcm->substream->number][device]; 143 } 144 145 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 146 { 147 return get_setup(dpcm)->notify; 148 } 149 150 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 151 { 152 return get_setup(dpcm)->rate_shift; 153 } 154 155 /* call in cable->lock */ 156 static void loopback_timer_start(struct loopback_pcm *dpcm) 157 { 158 unsigned long tick; 159 unsigned int rate_shift = get_rate_shift(dpcm); 160 161 if (rate_shift != dpcm->pcm_rate_shift) { 162 dpcm->pcm_rate_shift = rate_shift; 163 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 164 } 165 if (dpcm->period_size_frac <= dpcm->irq_pos) { 166 dpcm->irq_pos %= dpcm->period_size_frac; 167 dpcm->period_update_pending = 1; 168 } 169 tick = dpcm->period_size_frac - dpcm->irq_pos; 170 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 171 mod_timer(&dpcm->timer, jiffies + tick); 172 } 173 174 /* call in cable->lock */ 175 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 176 { 177 del_timer(&dpcm->timer); 178 dpcm->timer.expires = 0; 179 } 180 181 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm) 182 { 183 del_timer_sync(&dpcm->timer); 184 } 185 186 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 187 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 188 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 189 190 static int loopback_check_format(struct loopback_cable *cable, int stream) 191 { 192 struct snd_pcm_runtime *runtime, *cruntime; 193 struct loopback_setup *setup; 194 struct snd_card *card; 195 int check; 196 197 if (cable->valid != CABLE_VALID_BOTH) { 198 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 199 goto __notify; 200 return 0; 201 } 202 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 203 substream->runtime; 204 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 205 substream->runtime; 206 check = runtime->format != cruntime->format || 207 runtime->rate != cruntime->rate || 208 runtime->channels != cruntime->channels; 209 if (!check) 210 return 0; 211 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 212 return -EIO; 213 } else { 214 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 215 substream, SNDRV_PCM_STATE_DRAINING); 216 __notify: 217 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 218 substream->runtime; 219 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 220 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 221 if (setup->format != runtime->format) { 222 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 223 &setup->format_id); 224 setup->format = runtime->format; 225 } 226 if (setup->rate != runtime->rate) { 227 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 228 &setup->rate_id); 229 setup->rate = runtime->rate; 230 } 231 if (setup->channels != runtime->channels) { 232 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 233 &setup->channels_id); 234 setup->channels = runtime->channels; 235 } 236 } 237 return 0; 238 } 239 240 static void loopback_active_notify(struct loopback_pcm *dpcm) 241 { 242 snd_ctl_notify(dpcm->loopback->card, 243 SNDRV_CTL_EVENT_MASK_VALUE, 244 &get_setup(dpcm)->active_id); 245 } 246 247 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 248 { 249 struct snd_pcm_runtime *runtime = substream->runtime; 250 struct loopback_pcm *dpcm = runtime->private_data; 251 struct loopback_cable *cable = dpcm->cable; 252 int err, stream = 1 << substream->stream; 253 254 switch (cmd) { 255 case SNDRV_PCM_TRIGGER_START: 256 err = loopback_check_format(cable, substream->stream); 257 if (err < 0) 258 return err; 259 dpcm->last_jiffies = jiffies; 260 dpcm->pcm_rate_shift = 0; 261 dpcm->last_drift = 0; 262 spin_lock(&cable->lock); 263 cable->running |= stream; 264 cable->pause &= ~stream; 265 loopback_timer_start(dpcm); 266 spin_unlock(&cable->lock); 267 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 268 loopback_active_notify(dpcm); 269 break; 270 case SNDRV_PCM_TRIGGER_STOP: 271 spin_lock(&cable->lock); 272 cable->running &= ~stream; 273 cable->pause &= ~stream; 274 loopback_timer_stop(dpcm); 275 spin_unlock(&cable->lock); 276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 277 loopback_active_notify(dpcm); 278 break; 279 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 280 case SNDRV_PCM_TRIGGER_SUSPEND: 281 spin_lock(&cable->lock); 282 cable->pause |= stream; 283 loopback_timer_stop(dpcm); 284 spin_unlock(&cable->lock); 285 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 286 loopback_active_notify(dpcm); 287 break; 288 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 289 case SNDRV_PCM_TRIGGER_RESUME: 290 spin_lock(&cable->lock); 291 dpcm->last_jiffies = jiffies; 292 cable->pause &= ~stream; 293 loopback_timer_start(dpcm); 294 spin_unlock(&cable->lock); 295 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 296 loopback_active_notify(dpcm); 297 break; 298 default: 299 return -EINVAL; 300 } 301 return 0; 302 } 303 304 static void params_change(struct snd_pcm_substream *substream) 305 { 306 struct snd_pcm_runtime *runtime = substream->runtime; 307 struct loopback_pcm *dpcm = runtime->private_data; 308 struct loopback_cable *cable = dpcm->cable; 309 310 cable->hw.formats = pcm_format_to_bits(runtime->format); 311 cable->hw.rate_min = runtime->rate; 312 cable->hw.rate_max = runtime->rate; 313 cable->hw.channels_min = runtime->channels; 314 cable->hw.channels_max = runtime->channels; 315 } 316 317 static int loopback_prepare(struct snd_pcm_substream *substream) 318 { 319 struct snd_pcm_runtime *runtime = substream->runtime; 320 struct loopback_pcm *dpcm = runtime->private_data; 321 struct loopback_cable *cable = dpcm->cable; 322 int bps, salign; 323 324 loopback_timer_stop_sync(dpcm); 325 326 salign = (snd_pcm_format_physical_width(runtime->format) * 327 runtime->channels) / 8; 328 bps = salign * runtime->rate; 329 if (bps <= 0 || salign <= 0) 330 return -EINVAL; 331 332 dpcm->buf_pos = 0; 333 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 334 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 335 /* clear capture buffer */ 336 dpcm->silent_size = dpcm->pcm_buffer_size; 337 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 338 runtime->buffer_size * runtime->channels); 339 } 340 341 dpcm->irq_pos = 0; 342 dpcm->period_update_pending = 0; 343 dpcm->pcm_bps = bps; 344 dpcm->pcm_salign = salign; 345 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 346 347 mutex_lock(&dpcm->loopback->cable_lock); 348 if (!(cable->valid & ~(1 << substream->stream)) || 349 (get_setup(dpcm)->notify && 350 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 351 params_change(substream); 352 cable->valid |= 1 << substream->stream; 353 mutex_unlock(&dpcm->loopback->cable_lock); 354 355 return 0; 356 } 357 358 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 359 { 360 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 361 char *dst = runtime->dma_area; 362 unsigned int dst_off = dpcm->buf_pos; 363 364 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 365 return; 366 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 367 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 368 369 for (;;) { 370 unsigned int size = bytes; 371 if (dst_off + size > dpcm->pcm_buffer_size) 372 size = dpcm->pcm_buffer_size - dst_off; 373 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 374 bytes_to_frames(runtime, size) * 375 runtime->channels); 376 dpcm->silent_size += size; 377 bytes -= size; 378 if (!bytes) 379 break; 380 dst_off = 0; 381 } 382 } 383 384 static void copy_play_buf(struct loopback_pcm *play, 385 struct loopback_pcm *capt, 386 unsigned int bytes) 387 { 388 struct snd_pcm_runtime *runtime = play->substream->runtime; 389 char *src = runtime->dma_area; 390 char *dst = capt->substream->runtime->dma_area; 391 unsigned int src_off = play->buf_pos; 392 unsigned int dst_off = capt->buf_pos; 393 unsigned int clear_bytes = 0; 394 395 /* check if playback is draining, trim the capture copy size 396 * when our pointer is at the end of playback ring buffer */ 397 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 398 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 399 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 400 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 401 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 402 appl_ptr1 += play->buf_pos / play->pcm_salign; 403 if (appl_ptr < appl_ptr1) 404 appl_ptr1 -= runtime->buffer_size; 405 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 406 if (diff < bytes) { 407 clear_bytes = bytes - diff; 408 bytes = diff; 409 } 410 } 411 412 for (;;) { 413 unsigned int size = bytes; 414 if (src_off + size > play->pcm_buffer_size) 415 size = play->pcm_buffer_size - src_off; 416 if (dst_off + size > capt->pcm_buffer_size) 417 size = capt->pcm_buffer_size - dst_off; 418 memcpy(dst + dst_off, src + src_off, size); 419 capt->silent_size = 0; 420 bytes -= size; 421 if (!bytes) 422 break; 423 src_off = (src_off + size) % play->pcm_buffer_size; 424 dst_off = (dst_off + size) % capt->pcm_buffer_size; 425 } 426 427 if (clear_bytes > 0) { 428 clear_capture_buf(capt, clear_bytes); 429 capt->silent_size = 0; 430 } 431 } 432 433 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 434 unsigned int jiffies_delta) 435 { 436 unsigned long last_pos; 437 unsigned int delta; 438 439 last_pos = byte_pos(dpcm, dpcm->irq_pos); 440 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 441 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 442 if (delta >= dpcm->last_drift) 443 delta -= dpcm->last_drift; 444 dpcm->last_drift = 0; 445 if (dpcm->irq_pos >= dpcm->period_size_frac) { 446 dpcm->irq_pos %= dpcm->period_size_frac; 447 dpcm->period_update_pending = 1; 448 } 449 return delta; 450 } 451 452 static inline void bytepos_finish(struct loopback_pcm *dpcm, 453 unsigned int delta) 454 { 455 dpcm->buf_pos += delta; 456 dpcm->buf_pos %= dpcm->pcm_buffer_size; 457 } 458 459 /* call in cable->lock */ 460 static unsigned int loopback_pos_update(struct loopback_cable *cable) 461 { 462 struct loopback_pcm *dpcm_play = 463 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 464 struct loopback_pcm *dpcm_capt = 465 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 466 unsigned long delta_play = 0, delta_capt = 0; 467 unsigned int running, count1, count2; 468 469 running = cable->running ^ cable->pause; 470 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 471 delta_play = jiffies - dpcm_play->last_jiffies; 472 dpcm_play->last_jiffies += delta_play; 473 } 474 475 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 476 delta_capt = jiffies - dpcm_capt->last_jiffies; 477 dpcm_capt->last_jiffies += delta_capt; 478 } 479 480 if (delta_play == 0 && delta_capt == 0) 481 goto unlock; 482 483 if (delta_play > delta_capt) { 484 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 485 bytepos_finish(dpcm_play, count1); 486 delta_play = delta_capt; 487 } else if (delta_play < delta_capt) { 488 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 489 clear_capture_buf(dpcm_capt, count1); 490 bytepos_finish(dpcm_capt, count1); 491 delta_capt = delta_play; 492 } 493 494 if (delta_play == 0 && delta_capt == 0) 495 goto unlock; 496 497 /* note delta_capt == delta_play at this moment */ 498 count1 = bytepos_delta(dpcm_play, delta_play); 499 count2 = bytepos_delta(dpcm_capt, delta_capt); 500 if (count1 < count2) { 501 dpcm_capt->last_drift = count2 - count1; 502 count1 = count2; 503 } else if (count1 > count2) { 504 dpcm_play->last_drift = count1 - count2; 505 } 506 copy_play_buf(dpcm_play, dpcm_capt, count1); 507 bytepos_finish(dpcm_play, count1); 508 bytepos_finish(dpcm_capt, count1); 509 unlock: 510 return running; 511 } 512 513 static void loopback_timer_function(struct timer_list *t) 514 { 515 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer); 516 unsigned long flags; 517 518 spin_lock_irqsave(&dpcm->cable->lock, flags); 519 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 520 loopback_timer_start(dpcm); 521 if (dpcm->period_update_pending) { 522 dpcm->period_update_pending = 0; 523 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 524 /* need to unlock before calling below */ 525 snd_pcm_period_elapsed(dpcm->substream); 526 return; 527 } 528 } 529 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 530 } 531 532 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 533 { 534 struct snd_pcm_runtime *runtime = substream->runtime; 535 struct loopback_pcm *dpcm = runtime->private_data; 536 snd_pcm_uframes_t pos; 537 538 spin_lock(&dpcm->cable->lock); 539 loopback_pos_update(dpcm->cable); 540 pos = dpcm->buf_pos; 541 spin_unlock(&dpcm->cable->lock); 542 return bytes_to_frames(runtime, pos); 543 } 544 545 static const struct snd_pcm_hardware loopback_pcm_hardware = 546 { 547 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 548 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 549 SNDRV_PCM_INFO_RESUME), 550 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 551 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE | 552 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | 553 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 554 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 555 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 556 .rate_min = 8000, 557 .rate_max = 192000, 558 .channels_min = 1, 559 .channels_max = 32, 560 .buffer_bytes_max = 2 * 1024 * 1024, 561 .period_bytes_min = 64, 562 /* note check overflow in frac_pos() using pcm_rate_shift before 563 changing period_bytes_max value */ 564 .period_bytes_max = 1024 * 1024, 565 .periods_min = 1, 566 .periods_max = 1024, 567 .fifo_size = 0, 568 }; 569 570 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 571 { 572 struct loopback_pcm *dpcm = runtime->private_data; 573 kfree(dpcm); 574 } 575 576 static int loopback_hw_params(struct snd_pcm_substream *substream, 577 struct snd_pcm_hw_params *params) 578 { 579 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 580 params_buffer_bytes(params)); 581 } 582 583 static int loopback_hw_free(struct snd_pcm_substream *substream) 584 { 585 struct snd_pcm_runtime *runtime = substream->runtime; 586 struct loopback_pcm *dpcm = runtime->private_data; 587 struct loopback_cable *cable = dpcm->cable; 588 589 mutex_lock(&dpcm->loopback->cable_lock); 590 cable->valid &= ~(1 << substream->stream); 591 mutex_unlock(&dpcm->loopback->cable_lock); 592 return snd_pcm_lib_free_vmalloc_buffer(substream); 593 } 594 595 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 596 { 597 if (!substream->pcm->device) 598 return substream->stream; 599 else 600 return !substream->stream; 601 } 602 603 static int rule_format(struct snd_pcm_hw_params *params, 604 struct snd_pcm_hw_rule *rule) 605 { 606 struct loopback_pcm *dpcm = rule->private; 607 struct loopback_cable *cable = dpcm->cable; 608 struct snd_mask m; 609 610 snd_mask_none(&m); 611 mutex_lock(&dpcm->loopback->cable_lock); 612 m.bits[0] = (u_int32_t)cable->hw.formats; 613 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32); 614 mutex_unlock(&dpcm->loopback->cable_lock); 615 return snd_mask_refine(hw_param_mask(params, rule->var), &m); 616 } 617 618 static int rule_rate(struct snd_pcm_hw_params *params, 619 struct snd_pcm_hw_rule *rule) 620 { 621 struct loopback_pcm *dpcm = rule->private; 622 struct loopback_cable *cable = dpcm->cable; 623 struct snd_interval t; 624 625 mutex_lock(&dpcm->loopback->cable_lock); 626 t.min = cable->hw.rate_min; 627 t.max = cable->hw.rate_max; 628 mutex_unlock(&dpcm->loopback->cable_lock); 629 t.openmin = t.openmax = 0; 630 t.integer = 0; 631 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 632 } 633 634 static int rule_channels(struct snd_pcm_hw_params *params, 635 struct snd_pcm_hw_rule *rule) 636 { 637 struct loopback_pcm *dpcm = rule->private; 638 struct loopback_cable *cable = dpcm->cable; 639 struct snd_interval t; 640 641 mutex_lock(&dpcm->loopback->cable_lock); 642 t.min = cable->hw.channels_min; 643 t.max = cable->hw.channels_max; 644 mutex_unlock(&dpcm->loopback->cable_lock); 645 t.openmin = t.openmax = 0; 646 t.integer = 0; 647 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 648 } 649 650 static void free_cable(struct snd_pcm_substream *substream) 651 { 652 struct loopback *loopback = substream->private_data; 653 int dev = get_cable_index(substream); 654 struct loopback_cable *cable; 655 656 cable = loopback->cables[substream->number][dev]; 657 if (!cable) 658 return; 659 if (cable->streams[!substream->stream]) { 660 /* other stream is still alive */ 661 spin_lock_irq(&cable->lock); 662 cable->streams[substream->stream] = NULL; 663 spin_unlock_irq(&cable->lock); 664 } else { 665 /* free the cable */ 666 loopback->cables[substream->number][dev] = NULL; 667 kfree(cable); 668 } 669 } 670 671 static int loopback_open(struct snd_pcm_substream *substream) 672 { 673 struct snd_pcm_runtime *runtime = substream->runtime; 674 struct loopback *loopback = substream->private_data; 675 struct loopback_pcm *dpcm; 676 struct loopback_cable *cable = NULL; 677 int err = 0; 678 int dev = get_cable_index(substream); 679 680 mutex_lock(&loopback->cable_lock); 681 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 682 if (!dpcm) { 683 err = -ENOMEM; 684 goto unlock; 685 } 686 dpcm->loopback = loopback; 687 dpcm->substream = substream; 688 timer_setup(&dpcm->timer, loopback_timer_function, 0); 689 690 cable = loopback->cables[substream->number][dev]; 691 if (!cable) { 692 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 693 if (!cable) { 694 err = -ENOMEM; 695 goto unlock; 696 } 697 spin_lock_init(&cable->lock); 698 cable->hw = loopback_pcm_hardware; 699 loopback->cables[substream->number][dev] = cable; 700 } 701 dpcm->cable = cable; 702 703 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 704 705 /* use dynamic rules based on actual runtime->hw values */ 706 /* note that the default rules created in the PCM midlevel code */ 707 /* are cached -> they do not reflect the actual state */ 708 err = snd_pcm_hw_rule_add(runtime, 0, 709 SNDRV_PCM_HW_PARAM_FORMAT, 710 rule_format, dpcm, 711 SNDRV_PCM_HW_PARAM_FORMAT, -1); 712 if (err < 0) 713 goto unlock; 714 err = snd_pcm_hw_rule_add(runtime, 0, 715 SNDRV_PCM_HW_PARAM_RATE, 716 rule_rate, dpcm, 717 SNDRV_PCM_HW_PARAM_RATE, -1); 718 if (err < 0) 719 goto unlock; 720 err = snd_pcm_hw_rule_add(runtime, 0, 721 SNDRV_PCM_HW_PARAM_CHANNELS, 722 rule_channels, dpcm, 723 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 724 if (err < 0) 725 goto unlock; 726 727 runtime->private_data = dpcm; 728 runtime->private_free = loopback_runtime_free; 729 if (get_notify(dpcm)) 730 runtime->hw = loopback_pcm_hardware; 731 else 732 runtime->hw = cable->hw; 733 734 spin_lock_irq(&cable->lock); 735 cable->streams[substream->stream] = dpcm; 736 spin_unlock_irq(&cable->lock); 737 738 unlock: 739 if (err < 0) { 740 free_cable(substream); 741 kfree(dpcm); 742 } 743 mutex_unlock(&loopback->cable_lock); 744 return err; 745 } 746 747 static int loopback_close(struct snd_pcm_substream *substream) 748 { 749 struct loopback *loopback = substream->private_data; 750 struct loopback_pcm *dpcm = substream->runtime->private_data; 751 752 loopback_timer_stop_sync(dpcm); 753 mutex_lock(&loopback->cable_lock); 754 free_cable(substream); 755 mutex_unlock(&loopback->cable_lock); 756 return 0; 757 } 758 759 static const struct snd_pcm_ops loopback_pcm_ops = { 760 .open = loopback_open, 761 .close = loopback_close, 762 .ioctl = snd_pcm_lib_ioctl, 763 .hw_params = loopback_hw_params, 764 .hw_free = loopback_hw_free, 765 .prepare = loopback_prepare, 766 .trigger = loopback_trigger, 767 .pointer = loopback_pointer, 768 .page = snd_pcm_lib_get_vmalloc_page, 769 }; 770 771 static int loopback_pcm_new(struct loopback *loopback, 772 int device, int substreams) 773 { 774 struct snd_pcm *pcm; 775 int err; 776 777 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 778 substreams, substreams, &pcm); 779 if (err < 0) 780 return err; 781 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops); 782 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops); 783 784 pcm->private_data = loopback; 785 pcm->info_flags = 0; 786 strcpy(pcm->name, "Loopback PCM"); 787 788 loopback->pcm[device] = pcm; 789 return 0; 790 } 791 792 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 793 struct snd_ctl_elem_info *uinfo) 794 { 795 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 796 uinfo->count = 1; 797 uinfo->value.integer.min = 80000; 798 uinfo->value.integer.max = 120000; 799 uinfo->value.integer.step = 1; 800 return 0; 801 } 802 803 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 804 struct snd_ctl_elem_value *ucontrol) 805 { 806 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 807 808 mutex_lock(&loopback->cable_lock); 809 ucontrol->value.integer.value[0] = 810 loopback->setup[kcontrol->id.subdevice] 811 [kcontrol->id.device].rate_shift; 812 mutex_unlock(&loopback->cable_lock); 813 return 0; 814 } 815 816 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 817 struct snd_ctl_elem_value *ucontrol) 818 { 819 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 820 unsigned int val; 821 int change = 0; 822 823 val = ucontrol->value.integer.value[0]; 824 if (val < 80000) 825 val = 80000; 826 if (val > 120000) 827 val = 120000; 828 mutex_lock(&loopback->cable_lock); 829 if (val != loopback->setup[kcontrol->id.subdevice] 830 [kcontrol->id.device].rate_shift) { 831 loopback->setup[kcontrol->id.subdevice] 832 [kcontrol->id.device].rate_shift = val; 833 change = 1; 834 } 835 mutex_unlock(&loopback->cable_lock); 836 return change; 837 } 838 839 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 840 struct snd_ctl_elem_value *ucontrol) 841 { 842 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 843 844 mutex_lock(&loopback->cable_lock); 845 ucontrol->value.integer.value[0] = 846 loopback->setup[kcontrol->id.subdevice] 847 [kcontrol->id.device].notify; 848 mutex_unlock(&loopback->cable_lock); 849 return 0; 850 } 851 852 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 853 struct snd_ctl_elem_value *ucontrol) 854 { 855 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 856 unsigned int val; 857 int change = 0; 858 859 val = ucontrol->value.integer.value[0] ? 1 : 0; 860 mutex_lock(&loopback->cable_lock); 861 if (val != loopback->setup[kcontrol->id.subdevice] 862 [kcontrol->id.device].notify) { 863 loopback->setup[kcontrol->id.subdevice] 864 [kcontrol->id.device].notify = val; 865 change = 1; 866 } 867 mutex_unlock(&loopback->cable_lock); 868 return change; 869 } 870 871 static int loopback_active_get(struct snd_kcontrol *kcontrol, 872 struct snd_ctl_elem_value *ucontrol) 873 { 874 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 875 struct loopback_cable *cable; 876 877 unsigned int val = 0; 878 879 mutex_lock(&loopback->cable_lock); 880 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 881 if (cable != NULL) { 882 unsigned int running = cable->running ^ cable->pause; 883 884 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0; 885 } 886 mutex_unlock(&loopback->cable_lock); 887 ucontrol->value.integer.value[0] = val; 888 return 0; 889 } 890 891 static int loopback_format_info(struct snd_kcontrol *kcontrol, 892 struct snd_ctl_elem_info *uinfo) 893 { 894 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 895 uinfo->count = 1; 896 uinfo->value.integer.min = 0; 897 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 898 uinfo->value.integer.step = 1; 899 return 0; 900 } 901 902 static int loopback_format_get(struct snd_kcontrol *kcontrol, 903 struct snd_ctl_elem_value *ucontrol) 904 { 905 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 906 907 ucontrol->value.integer.value[0] = 908 loopback->setup[kcontrol->id.subdevice] 909 [kcontrol->id.device].format; 910 return 0; 911 } 912 913 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 914 struct snd_ctl_elem_info *uinfo) 915 { 916 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 917 uinfo->count = 1; 918 uinfo->value.integer.min = 0; 919 uinfo->value.integer.max = 192000; 920 uinfo->value.integer.step = 1; 921 return 0; 922 } 923 924 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 925 struct snd_ctl_elem_value *ucontrol) 926 { 927 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 928 929 mutex_lock(&loopback->cable_lock); 930 ucontrol->value.integer.value[0] = 931 loopback->setup[kcontrol->id.subdevice] 932 [kcontrol->id.device].rate; 933 mutex_unlock(&loopback->cable_lock); 934 return 0; 935 } 936 937 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 938 struct snd_ctl_elem_info *uinfo) 939 { 940 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 941 uinfo->count = 1; 942 uinfo->value.integer.min = 1; 943 uinfo->value.integer.max = 1024; 944 uinfo->value.integer.step = 1; 945 return 0; 946 } 947 948 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 949 struct snd_ctl_elem_value *ucontrol) 950 { 951 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 952 953 mutex_lock(&loopback->cable_lock); 954 ucontrol->value.integer.value[0] = 955 loopback->setup[kcontrol->id.subdevice] 956 [kcontrol->id.device].channels; 957 mutex_unlock(&loopback->cable_lock); 958 return 0; 959 } 960 961 static struct snd_kcontrol_new loopback_controls[] = { 962 { 963 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 964 .name = "PCM Rate Shift 100000", 965 .info = loopback_rate_shift_info, 966 .get = loopback_rate_shift_get, 967 .put = loopback_rate_shift_put, 968 }, 969 { 970 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 971 .name = "PCM Notify", 972 .info = snd_ctl_boolean_mono_info, 973 .get = loopback_notify_get, 974 .put = loopback_notify_put, 975 }, 976 #define ACTIVE_IDX 2 977 { 978 .access = SNDRV_CTL_ELEM_ACCESS_READ, 979 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 980 .name = "PCM Slave Active", 981 .info = snd_ctl_boolean_mono_info, 982 .get = loopback_active_get, 983 }, 984 #define FORMAT_IDX 3 985 { 986 .access = SNDRV_CTL_ELEM_ACCESS_READ, 987 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 988 .name = "PCM Slave Format", 989 .info = loopback_format_info, 990 .get = loopback_format_get 991 }, 992 #define RATE_IDX 4 993 { 994 .access = SNDRV_CTL_ELEM_ACCESS_READ, 995 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 996 .name = "PCM Slave Rate", 997 .info = loopback_rate_info, 998 .get = loopback_rate_get 999 }, 1000 #define CHANNELS_IDX 5 1001 { 1002 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1003 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1004 .name = "PCM Slave Channels", 1005 .info = loopback_channels_info, 1006 .get = loopback_channels_get 1007 } 1008 }; 1009 1010 static int loopback_mixer_new(struct loopback *loopback, int notify) 1011 { 1012 struct snd_card *card = loopback->card; 1013 struct snd_pcm *pcm; 1014 struct snd_kcontrol *kctl; 1015 struct loopback_setup *setup; 1016 int err, dev, substr, substr_count, idx; 1017 1018 strcpy(card->mixername, "Loopback Mixer"); 1019 for (dev = 0; dev < 2; dev++) { 1020 pcm = loopback->pcm[dev]; 1021 substr_count = 1022 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1023 for (substr = 0; substr < substr_count; substr++) { 1024 setup = &loopback->setup[substr][dev]; 1025 setup->notify = notify; 1026 setup->rate_shift = NO_PITCH; 1027 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1028 setup->rate = 48000; 1029 setup->channels = 2; 1030 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1031 idx++) { 1032 kctl = snd_ctl_new1(&loopback_controls[idx], 1033 loopback); 1034 if (!kctl) 1035 return -ENOMEM; 1036 kctl->id.device = dev; 1037 kctl->id.subdevice = substr; 1038 switch (idx) { 1039 case ACTIVE_IDX: 1040 setup->active_id = kctl->id; 1041 break; 1042 case FORMAT_IDX: 1043 setup->format_id = kctl->id; 1044 break; 1045 case RATE_IDX: 1046 setup->rate_id = kctl->id; 1047 break; 1048 case CHANNELS_IDX: 1049 setup->channels_id = kctl->id; 1050 break; 1051 default: 1052 break; 1053 } 1054 err = snd_ctl_add(card, kctl); 1055 if (err < 0) 1056 return err; 1057 } 1058 } 1059 } 1060 return 0; 1061 } 1062 1063 static void print_dpcm_info(struct snd_info_buffer *buffer, 1064 struct loopback_pcm *dpcm, 1065 const char *id) 1066 { 1067 snd_iprintf(buffer, " %s\n", id); 1068 if (dpcm == NULL) { 1069 snd_iprintf(buffer, " inactive\n"); 1070 return; 1071 } 1072 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1073 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1074 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1075 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1076 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1077 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1078 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1079 snd_iprintf(buffer, " update_pending:\t%u\n", 1080 dpcm->period_update_pending); 1081 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1082 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1083 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1084 dpcm->last_jiffies, jiffies); 1085 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1086 } 1087 1088 static void print_substream_info(struct snd_info_buffer *buffer, 1089 struct loopback *loopback, 1090 int sub, 1091 int num) 1092 { 1093 struct loopback_cable *cable = loopback->cables[sub][num]; 1094 1095 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1096 if (cable == NULL) { 1097 snd_iprintf(buffer, " inactive\n"); 1098 return; 1099 } 1100 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1101 snd_iprintf(buffer, " running: %u\n", cable->running); 1102 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1103 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1104 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1105 } 1106 1107 static void print_cable_info(struct snd_info_entry *entry, 1108 struct snd_info_buffer *buffer) 1109 { 1110 struct loopback *loopback = entry->private_data; 1111 int sub, num; 1112 1113 mutex_lock(&loopback->cable_lock); 1114 num = entry->name[strlen(entry->name)-1]; 1115 num = num == '0' ? 0 : 1; 1116 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1117 print_substream_info(buffer, loopback, sub, num); 1118 mutex_unlock(&loopback->cable_lock); 1119 } 1120 1121 static int loopback_proc_new(struct loopback *loopback, int cidx) 1122 { 1123 char name[32]; 1124 1125 snprintf(name, sizeof(name), "cable#%d", cidx); 1126 return snd_card_ro_proc_new(loopback->card, name, loopback, 1127 print_cable_info); 1128 } 1129 1130 static int loopback_probe(struct platform_device *devptr) 1131 { 1132 struct snd_card *card; 1133 struct loopback *loopback; 1134 int dev = devptr->id; 1135 int err; 1136 1137 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE, 1138 sizeof(struct loopback), &card); 1139 if (err < 0) 1140 return err; 1141 loopback = card->private_data; 1142 1143 if (pcm_substreams[dev] < 1) 1144 pcm_substreams[dev] = 1; 1145 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1146 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1147 1148 loopback->card = card; 1149 mutex_init(&loopback->cable_lock); 1150 1151 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1152 if (err < 0) 1153 goto __nodev; 1154 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1155 if (err < 0) 1156 goto __nodev; 1157 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1158 if (err < 0) 1159 goto __nodev; 1160 loopback_proc_new(loopback, 0); 1161 loopback_proc_new(loopback, 1); 1162 strcpy(card->driver, "Loopback"); 1163 strcpy(card->shortname, "Loopback"); 1164 sprintf(card->longname, "Loopback %i", dev + 1); 1165 err = snd_card_register(card); 1166 if (!err) { 1167 platform_set_drvdata(devptr, card); 1168 return 0; 1169 } 1170 __nodev: 1171 snd_card_free(card); 1172 return err; 1173 } 1174 1175 static int loopback_remove(struct platform_device *devptr) 1176 { 1177 snd_card_free(platform_get_drvdata(devptr)); 1178 return 0; 1179 } 1180 1181 #ifdef CONFIG_PM_SLEEP 1182 static int loopback_suspend(struct device *pdev) 1183 { 1184 struct snd_card *card = dev_get_drvdata(pdev); 1185 1186 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1187 return 0; 1188 } 1189 1190 static int loopback_resume(struct device *pdev) 1191 { 1192 struct snd_card *card = dev_get_drvdata(pdev); 1193 1194 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1195 return 0; 1196 } 1197 1198 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1199 #define LOOPBACK_PM_OPS &loopback_pm 1200 #else 1201 #define LOOPBACK_PM_OPS NULL 1202 #endif 1203 1204 #define SND_LOOPBACK_DRIVER "snd_aloop" 1205 1206 static struct platform_driver loopback_driver = { 1207 .probe = loopback_probe, 1208 .remove = loopback_remove, 1209 .driver = { 1210 .name = SND_LOOPBACK_DRIVER, 1211 .pm = LOOPBACK_PM_OPS, 1212 }, 1213 }; 1214 1215 static void loopback_unregister_all(void) 1216 { 1217 int i; 1218 1219 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1220 platform_device_unregister(devices[i]); 1221 platform_driver_unregister(&loopback_driver); 1222 } 1223 1224 static int __init alsa_card_loopback_init(void) 1225 { 1226 int i, err, cards; 1227 1228 err = platform_driver_register(&loopback_driver); 1229 if (err < 0) 1230 return err; 1231 1232 1233 cards = 0; 1234 for (i = 0; i < SNDRV_CARDS; i++) { 1235 struct platform_device *device; 1236 if (!enable[i]) 1237 continue; 1238 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1239 i, NULL, 0); 1240 if (IS_ERR(device)) 1241 continue; 1242 if (!platform_get_drvdata(device)) { 1243 platform_device_unregister(device); 1244 continue; 1245 } 1246 devices[i] = device; 1247 cards++; 1248 } 1249 if (!cards) { 1250 #ifdef MODULE 1251 printk(KERN_ERR "aloop: No loopback enabled\n"); 1252 #endif 1253 loopback_unregister_all(); 1254 return -ENODEV; 1255 } 1256 return 0; 1257 } 1258 1259 static void __exit alsa_card_loopback_exit(void) 1260 { 1261 loopback_unregister_all(); 1262 } 1263 1264 module_init(alsa_card_loopback_init) 1265 module_exit(alsa_card_loopback_exit) 1266