1 /* 2 * Loopback soundcard 3 * 4 * Original code: 5 * Copyright (c) by Jaroslav Kysela <perex@perex.cz> 6 * 7 * More accurate positioning and full-duplex support: 8 * Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de> 9 * 10 * Major (almost complete) rewrite: 11 * Copyright (c) by Takashi Iwai <tiwai@suse.de> 12 * 13 * A next major update in 2010 (separate timers for playback and capture): 14 * Copyright (c) Jaroslav Kysela <perex@perex.cz> 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License as published by 18 * the Free Software Foundation; either version 2 of the License, or 19 * (at your option) any later version. 20 * 21 * This program is distributed in the hope that it will be useful, 22 * but WITHOUT ANY WARRANTY; without even the implied warranty of 23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 24 * GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with this program; if not, write to the Free Software 28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 29 * 30 */ 31 32 #include <linux/init.h> 33 #include <linux/jiffies.h> 34 #include <linux/slab.h> 35 #include <linux/time.h> 36 #include <linux/wait.h> 37 #include <linux/module.h> 38 #include <linux/platform_device.h> 39 #include <sound/core.h> 40 #include <sound/control.h> 41 #include <sound/pcm.h> 42 #include <sound/pcm_params.h> 43 #include <sound/info.h> 44 #include <sound/initval.h> 45 46 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 47 MODULE_DESCRIPTION("A loopback soundcard"); 48 MODULE_LICENSE("GPL"); 49 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 50 51 #define MAX_PCM_SUBSTREAMS 8 52 53 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 54 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 55 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 56 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 57 static int pcm_notify[SNDRV_CARDS]; 58 59 module_param_array(index, int, NULL, 0444); 60 MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 61 module_param_array(id, charp, NULL, 0444); 62 MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 63 module_param_array(enable, bool, NULL, 0444); 64 MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 65 module_param_array(pcm_substreams, int, NULL, 0444); 66 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 67 module_param_array(pcm_notify, int, NULL, 0444); 68 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 69 70 #define NO_PITCH 100000 71 72 struct loopback_pcm; 73 74 struct loopback_cable { 75 spinlock_t lock; 76 struct loopback_pcm *streams[2]; 77 struct snd_pcm_hardware hw; 78 /* flags */ 79 unsigned int valid; 80 unsigned int running; 81 unsigned int pause; 82 }; 83 84 struct loopback_setup { 85 unsigned int notify: 1; 86 unsigned int rate_shift; 87 unsigned int format; 88 unsigned int rate; 89 unsigned int channels; 90 struct snd_ctl_elem_id active_id; 91 struct snd_ctl_elem_id format_id; 92 struct snd_ctl_elem_id rate_id; 93 struct snd_ctl_elem_id channels_id; 94 }; 95 96 struct loopback { 97 struct snd_card *card; 98 struct mutex cable_lock; 99 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 100 struct snd_pcm *pcm[2]; 101 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 102 }; 103 104 struct loopback_pcm { 105 struct loopback *loopback; 106 struct snd_pcm_substream *substream; 107 struct loopback_cable *cable; 108 unsigned int pcm_buffer_size; 109 unsigned int buf_pos; /* position in buffer */ 110 unsigned int silent_size; 111 /* PCM parameters */ 112 unsigned int pcm_period_size; 113 unsigned int pcm_bps; /* bytes per second */ 114 unsigned int pcm_salign; /* bytes per sample * channels */ 115 unsigned int pcm_rate_shift; /* rate shift value */ 116 /* flags */ 117 unsigned int period_update_pending :1; 118 /* timer stuff */ 119 unsigned int irq_pos; /* fractional IRQ position */ 120 unsigned int period_size_frac; 121 unsigned int last_drift; 122 unsigned long last_jiffies; 123 struct timer_list timer; 124 }; 125 126 static struct platform_device *devices[SNDRV_CARDS]; 127 128 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 129 { 130 if (dpcm->pcm_rate_shift == NO_PITCH) { 131 x /= HZ; 132 } else { 133 x = div_u64(NO_PITCH * (unsigned long long)x, 134 HZ * (unsigned long long)dpcm->pcm_rate_shift); 135 } 136 return x - (x % dpcm->pcm_salign); 137 } 138 139 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 140 { 141 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 142 return x * HZ; 143 } else { 144 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 145 NO_PITCH); 146 } 147 return x; 148 } 149 150 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 151 { 152 int device = dpcm->substream->pstr->pcm->device; 153 154 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 155 device ^= 1; 156 return &dpcm->loopback->setup[dpcm->substream->number][device]; 157 } 158 159 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 160 { 161 return get_setup(dpcm)->notify; 162 } 163 164 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 165 { 166 return get_setup(dpcm)->rate_shift; 167 } 168 169 /* call in cable->lock */ 170 static void loopback_timer_start(struct loopback_pcm *dpcm) 171 { 172 unsigned long tick; 173 unsigned int rate_shift = get_rate_shift(dpcm); 174 175 if (rate_shift != dpcm->pcm_rate_shift) { 176 dpcm->pcm_rate_shift = rate_shift; 177 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 178 } 179 if (dpcm->period_size_frac <= dpcm->irq_pos) { 180 dpcm->irq_pos %= dpcm->period_size_frac; 181 dpcm->period_update_pending = 1; 182 } 183 tick = dpcm->period_size_frac - dpcm->irq_pos; 184 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 185 mod_timer(&dpcm->timer, jiffies + tick); 186 } 187 188 /* call in cable->lock */ 189 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 190 { 191 del_timer(&dpcm->timer); 192 dpcm->timer.expires = 0; 193 } 194 195 static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm) 196 { 197 del_timer_sync(&dpcm->timer); 198 } 199 200 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 201 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 202 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 203 204 static int loopback_check_format(struct loopback_cable *cable, int stream) 205 { 206 struct snd_pcm_runtime *runtime, *cruntime; 207 struct loopback_setup *setup; 208 struct snd_card *card; 209 int check; 210 211 if (cable->valid != CABLE_VALID_BOTH) { 212 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 213 goto __notify; 214 return 0; 215 } 216 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 217 substream->runtime; 218 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 219 substream->runtime; 220 check = runtime->format != cruntime->format || 221 runtime->rate != cruntime->rate || 222 runtime->channels != cruntime->channels; 223 if (!check) 224 return 0; 225 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 226 return -EIO; 227 } else { 228 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 229 substream, SNDRV_PCM_STATE_DRAINING); 230 __notify: 231 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 232 substream->runtime; 233 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 234 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 235 if (setup->format != runtime->format) { 236 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 237 &setup->format_id); 238 setup->format = runtime->format; 239 } 240 if (setup->rate != runtime->rate) { 241 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 242 &setup->rate_id); 243 setup->rate = runtime->rate; 244 } 245 if (setup->channels != runtime->channels) { 246 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 247 &setup->channels_id); 248 setup->channels = runtime->channels; 249 } 250 } 251 return 0; 252 } 253 254 static void loopback_active_notify(struct loopback_pcm *dpcm) 255 { 256 snd_ctl_notify(dpcm->loopback->card, 257 SNDRV_CTL_EVENT_MASK_VALUE, 258 &get_setup(dpcm)->active_id); 259 } 260 261 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 262 { 263 struct snd_pcm_runtime *runtime = substream->runtime; 264 struct loopback_pcm *dpcm = runtime->private_data; 265 struct loopback_cable *cable = dpcm->cable; 266 int err, stream = 1 << substream->stream; 267 268 switch (cmd) { 269 case SNDRV_PCM_TRIGGER_START: 270 err = loopback_check_format(cable, substream->stream); 271 if (err < 0) 272 return err; 273 dpcm->last_jiffies = jiffies; 274 dpcm->pcm_rate_shift = 0; 275 dpcm->last_drift = 0; 276 spin_lock(&cable->lock); 277 cable->running |= stream; 278 cable->pause &= ~stream; 279 loopback_timer_start(dpcm); 280 spin_unlock(&cable->lock); 281 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 282 loopback_active_notify(dpcm); 283 break; 284 case SNDRV_PCM_TRIGGER_STOP: 285 spin_lock(&cable->lock); 286 cable->running &= ~stream; 287 cable->pause &= ~stream; 288 loopback_timer_stop(dpcm); 289 spin_unlock(&cable->lock); 290 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 291 loopback_active_notify(dpcm); 292 break; 293 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 294 case SNDRV_PCM_TRIGGER_SUSPEND: 295 spin_lock(&cable->lock); 296 cable->pause |= stream; 297 loopback_timer_stop(dpcm); 298 spin_unlock(&cable->lock); 299 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 300 loopback_active_notify(dpcm); 301 break; 302 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 303 case SNDRV_PCM_TRIGGER_RESUME: 304 spin_lock(&cable->lock); 305 dpcm->last_jiffies = jiffies; 306 cable->pause &= ~stream; 307 loopback_timer_start(dpcm); 308 spin_unlock(&cable->lock); 309 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 310 loopback_active_notify(dpcm); 311 break; 312 default: 313 return -EINVAL; 314 } 315 return 0; 316 } 317 318 static void params_change(struct snd_pcm_substream *substream) 319 { 320 struct snd_pcm_runtime *runtime = substream->runtime; 321 struct loopback_pcm *dpcm = runtime->private_data; 322 struct loopback_cable *cable = dpcm->cable; 323 324 cable->hw.formats = pcm_format_to_bits(runtime->format); 325 cable->hw.rate_min = runtime->rate; 326 cable->hw.rate_max = runtime->rate; 327 cable->hw.channels_min = runtime->channels; 328 cable->hw.channels_max = runtime->channels; 329 } 330 331 static int loopback_prepare(struct snd_pcm_substream *substream) 332 { 333 struct snd_pcm_runtime *runtime = substream->runtime; 334 struct loopback_pcm *dpcm = runtime->private_data; 335 struct loopback_cable *cable = dpcm->cable; 336 int bps, salign; 337 338 loopback_timer_stop_sync(dpcm); 339 340 salign = (snd_pcm_format_width(runtime->format) * 341 runtime->channels) / 8; 342 bps = salign * runtime->rate; 343 if (bps <= 0 || salign <= 0) 344 return -EINVAL; 345 346 dpcm->buf_pos = 0; 347 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 348 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 349 /* clear capture buffer */ 350 dpcm->silent_size = dpcm->pcm_buffer_size; 351 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 352 runtime->buffer_size * runtime->channels); 353 } 354 355 dpcm->irq_pos = 0; 356 dpcm->period_update_pending = 0; 357 dpcm->pcm_bps = bps; 358 dpcm->pcm_salign = salign; 359 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 360 361 mutex_lock(&dpcm->loopback->cable_lock); 362 if (!(cable->valid & ~(1 << substream->stream)) || 363 (get_setup(dpcm)->notify && 364 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 365 params_change(substream); 366 cable->valid |= 1 << substream->stream; 367 mutex_unlock(&dpcm->loopback->cable_lock); 368 369 return 0; 370 } 371 372 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 373 { 374 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 375 char *dst = runtime->dma_area; 376 unsigned int dst_off = dpcm->buf_pos; 377 378 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 379 return; 380 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 381 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 382 383 for (;;) { 384 unsigned int size = bytes; 385 if (dst_off + size > dpcm->pcm_buffer_size) 386 size = dpcm->pcm_buffer_size - dst_off; 387 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 388 bytes_to_frames(runtime, size) * 389 runtime->channels); 390 dpcm->silent_size += size; 391 bytes -= size; 392 if (!bytes) 393 break; 394 dst_off = 0; 395 } 396 } 397 398 static void copy_play_buf(struct loopback_pcm *play, 399 struct loopback_pcm *capt, 400 unsigned int bytes) 401 { 402 struct snd_pcm_runtime *runtime = play->substream->runtime; 403 char *src = runtime->dma_area; 404 char *dst = capt->substream->runtime->dma_area; 405 unsigned int src_off = play->buf_pos; 406 unsigned int dst_off = capt->buf_pos; 407 unsigned int clear_bytes = 0; 408 409 /* check if playback is draining, trim the capture copy size 410 * when our pointer is at the end of playback ring buffer */ 411 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 412 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 413 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 414 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 415 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 416 appl_ptr1 += play->buf_pos / play->pcm_salign; 417 if (appl_ptr < appl_ptr1) 418 appl_ptr1 -= runtime->buffer_size; 419 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 420 if (diff < bytes) { 421 clear_bytes = bytes - diff; 422 bytes = diff; 423 } 424 } 425 426 for (;;) { 427 unsigned int size = bytes; 428 if (src_off + size > play->pcm_buffer_size) 429 size = play->pcm_buffer_size - src_off; 430 if (dst_off + size > capt->pcm_buffer_size) 431 size = capt->pcm_buffer_size - dst_off; 432 memcpy(dst + dst_off, src + src_off, size); 433 capt->silent_size = 0; 434 bytes -= size; 435 if (!bytes) 436 break; 437 src_off = (src_off + size) % play->pcm_buffer_size; 438 dst_off = (dst_off + size) % capt->pcm_buffer_size; 439 } 440 441 if (clear_bytes > 0) { 442 clear_capture_buf(capt, clear_bytes); 443 capt->silent_size = 0; 444 } 445 } 446 447 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 448 unsigned int jiffies_delta) 449 { 450 unsigned long last_pos; 451 unsigned int delta; 452 453 last_pos = byte_pos(dpcm, dpcm->irq_pos); 454 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 455 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 456 if (delta >= dpcm->last_drift) 457 delta -= dpcm->last_drift; 458 dpcm->last_drift = 0; 459 if (dpcm->irq_pos >= dpcm->period_size_frac) { 460 dpcm->irq_pos %= dpcm->period_size_frac; 461 dpcm->period_update_pending = 1; 462 } 463 return delta; 464 } 465 466 static inline void bytepos_finish(struct loopback_pcm *dpcm, 467 unsigned int delta) 468 { 469 dpcm->buf_pos += delta; 470 dpcm->buf_pos %= dpcm->pcm_buffer_size; 471 } 472 473 /* call in cable->lock */ 474 static unsigned int loopback_pos_update(struct loopback_cable *cable) 475 { 476 struct loopback_pcm *dpcm_play = 477 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 478 struct loopback_pcm *dpcm_capt = 479 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 480 unsigned long delta_play = 0, delta_capt = 0; 481 unsigned int running, count1, count2; 482 483 running = cable->running ^ cable->pause; 484 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 485 delta_play = jiffies - dpcm_play->last_jiffies; 486 dpcm_play->last_jiffies += delta_play; 487 } 488 489 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 490 delta_capt = jiffies - dpcm_capt->last_jiffies; 491 dpcm_capt->last_jiffies += delta_capt; 492 } 493 494 if (delta_play == 0 && delta_capt == 0) 495 goto unlock; 496 497 if (delta_play > delta_capt) { 498 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 499 bytepos_finish(dpcm_play, count1); 500 delta_play = delta_capt; 501 } else if (delta_play < delta_capt) { 502 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 503 clear_capture_buf(dpcm_capt, count1); 504 bytepos_finish(dpcm_capt, count1); 505 delta_capt = delta_play; 506 } 507 508 if (delta_play == 0 && delta_capt == 0) 509 goto unlock; 510 511 /* note delta_capt == delta_play at this moment */ 512 count1 = bytepos_delta(dpcm_play, delta_play); 513 count2 = bytepos_delta(dpcm_capt, delta_capt); 514 if (count1 < count2) { 515 dpcm_capt->last_drift = count2 - count1; 516 count1 = count2; 517 } else if (count1 > count2) { 518 dpcm_play->last_drift = count1 - count2; 519 } 520 copy_play_buf(dpcm_play, dpcm_capt, count1); 521 bytepos_finish(dpcm_play, count1); 522 bytepos_finish(dpcm_capt, count1); 523 unlock: 524 return running; 525 } 526 527 static void loopback_timer_function(struct timer_list *t) 528 { 529 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer); 530 unsigned long flags; 531 532 spin_lock_irqsave(&dpcm->cable->lock, flags); 533 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 534 loopback_timer_start(dpcm); 535 if (dpcm->period_update_pending) { 536 dpcm->period_update_pending = 0; 537 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 538 /* need to unlock before calling below */ 539 snd_pcm_period_elapsed(dpcm->substream); 540 return; 541 } 542 } 543 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 544 } 545 546 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 547 { 548 struct snd_pcm_runtime *runtime = substream->runtime; 549 struct loopback_pcm *dpcm = runtime->private_data; 550 snd_pcm_uframes_t pos; 551 552 spin_lock(&dpcm->cable->lock); 553 loopback_pos_update(dpcm->cable); 554 pos = dpcm->buf_pos; 555 spin_unlock(&dpcm->cable->lock); 556 return bytes_to_frames(runtime, pos); 557 } 558 559 static const struct snd_pcm_hardware loopback_pcm_hardware = 560 { 561 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 562 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 563 SNDRV_PCM_INFO_RESUME), 564 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 565 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 566 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 567 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 568 .rate_min = 8000, 569 .rate_max = 192000, 570 .channels_min = 1, 571 .channels_max = 32, 572 .buffer_bytes_max = 2 * 1024 * 1024, 573 .period_bytes_min = 64, 574 /* note check overflow in frac_pos() using pcm_rate_shift before 575 changing period_bytes_max value */ 576 .period_bytes_max = 1024 * 1024, 577 .periods_min = 1, 578 .periods_max = 1024, 579 .fifo_size = 0, 580 }; 581 582 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 583 { 584 struct loopback_pcm *dpcm = runtime->private_data; 585 kfree(dpcm); 586 } 587 588 static int loopback_hw_params(struct snd_pcm_substream *substream, 589 struct snd_pcm_hw_params *params) 590 { 591 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 592 params_buffer_bytes(params)); 593 } 594 595 static int loopback_hw_free(struct snd_pcm_substream *substream) 596 { 597 struct snd_pcm_runtime *runtime = substream->runtime; 598 struct loopback_pcm *dpcm = runtime->private_data; 599 struct loopback_cable *cable = dpcm->cable; 600 601 mutex_lock(&dpcm->loopback->cable_lock); 602 cable->valid &= ~(1 << substream->stream); 603 mutex_unlock(&dpcm->loopback->cable_lock); 604 return snd_pcm_lib_free_vmalloc_buffer(substream); 605 } 606 607 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 608 { 609 if (!substream->pcm->device) 610 return substream->stream; 611 else 612 return !substream->stream; 613 } 614 615 static int rule_format(struct snd_pcm_hw_params *params, 616 struct snd_pcm_hw_rule *rule) 617 { 618 struct loopback_pcm *dpcm = rule->private; 619 struct loopback_cable *cable = dpcm->cable; 620 struct snd_mask m; 621 622 snd_mask_none(&m); 623 mutex_lock(&dpcm->loopback->cable_lock); 624 m.bits[0] = (u_int32_t)cable->hw.formats; 625 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32); 626 mutex_unlock(&dpcm->loopback->cable_lock); 627 return snd_mask_refine(hw_param_mask(params, rule->var), &m); 628 } 629 630 static int rule_rate(struct snd_pcm_hw_params *params, 631 struct snd_pcm_hw_rule *rule) 632 { 633 struct loopback_pcm *dpcm = rule->private; 634 struct loopback_cable *cable = dpcm->cable; 635 struct snd_interval t; 636 637 mutex_lock(&dpcm->loopback->cable_lock); 638 t.min = cable->hw.rate_min; 639 t.max = cable->hw.rate_max; 640 mutex_unlock(&dpcm->loopback->cable_lock); 641 t.openmin = t.openmax = 0; 642 t.integer = 0; 643 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 644 } 645 646 static int rule_channels(struct snd_pcm_hw_params *params, 647 struct snd_pcm_hw_rule *rule) 648 { 649 struct loopback_pcm *dpcm = rule->private; 650 struct loopback_cable *cable = dpcm->cable; 651 struct snd_interval t; 652 653 mutex_lock(&dpcm->loopback->cable_lock); 654 t.min = cable->hw.channels_min; 655 t.max = cable->hw.channels_max; 656 mutex_unlock(&dpcm->loopback->cable_lock); 657 t.openmin = t.openmax = 0; 658 t.integer = 0; 659 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 660 } 661 662 static void free_cable(struct snd_pcm_substream *substream) 663 { 664 struct loopback *loopback = substream->private_data; 665 int dev = get_cable_index(substream); 666 struct loopback_cable *cable; 667 668 cable = loopback->cables[substream->number][dev]; 669 if (!cable) 670 return; 671 if (cable->streams[!substream->stream]) { 672 /* other stream is still alive */ 673 spin_lock_irq(&cable->lock); 674 cable->streams[substream->stream] = NULL; 675 spin_unlock_irq(&cable->lock); 676 } else { 677 /* free the cable */ 678 loopback->cables[substream->number][dev] = NULL; 679 kfree(cable); 680 } 681 } 682 683 static int loopback_open(struct snd_pcm_substream *substream) 684 { 685 struct snd_pcm_runtime *runtime = substream->runtime; 686 struct loopback *loopback = substream->private_data; 687 struct loopback_pcm *dpcm; 688 struct loopback_cable *cable = NULL; 689 int err = 0; 690 int dev = get_cable_index(substream); 691 692 mutex_lock(&loopback->cable_lock); 693 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 694 if (!dpcm) { 695 err = -ENOMEM; 696 goto unlock; 697 } 698 dpcm->loopback = loopback; 699 dpcm->substream = substream; 700 timer_setup(&dpcm->timer, loopback_timer_function, 0); 701 702 cable = loopback->cables[substream->number][dev]; 703 if (!cable) { 704 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 705 if (!cable) { 706 err = -ENOMEM; 707 goto unlock; 708 } 709 spin_lock_init(&cable->lock); 710 cable->hw = loopback_pcm_hardware; 711 loopback->cables[substream->number][dev] = cable; 712 } 713 dpcm->cable = cable; 714 715 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 716 717 /* use dynamic rules based on actual runtime->hw values */ 718 /* note that the default rules created in the PCM midlevel code */ 719 /* are cached -> they do not reflect the actual state */ 720 err = snd_pcm_hw_rule_add(runtime, 0, 721 SNDRV_PCM_HW_PARAM_FORMAT, 722 rule_format, dpcm, 723 SNDRV_PCM_HW_PARAM_FORMAT, -1); 724 if (err < 0) 725 goto unlock; 726 err = snd_pcm_hw_rule_add(runtime, 0, 727 SNDRV_PCM_HW_PARAM_RATE, 728 rule_rate, dpcm, 729 SNDRV_PCM_HW_PARAM_RATE, -1); 730 if (err < 0) 731 goto unlock; 732 err = snd_pcm_hw_rule_add(runtime, 0, 733 SNDRV_PCM_HW_PARAM_CHANNELS, 734 rule_channels, dpcm, 735 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 736 if (err < 0) 737 goto unlock; 738 739 runtime->private_data = dpcm; 740 runtime->private_free = loopback_runtime_free; 741 if (get_notify(dpcm)) 742 runtime->hw = loopback_pcm_hardware; 743 else 744 runtime->hw = cable->hw; 745 746 spin_lock_irq(&cable->lock); 747 cable->streams[substream->stream] = dpcm; 748 spin_unlock_irq(&cable->lock); 749 750 unlock: 751 if (err < 0) { 752 free_cable(substream); 753 kfree(dpcm); 754 } 755 mutex_unlock(&loopback->cable_lock); 756 return err; 757 } 758 759 static int loopback_close(struct snd_pcm_substream *substream) 760 { 761 struct loopback *loopback = substream->private_data; 762 struct loopback_pcm *dpcm = substream->runtime->private_data; 763 764 loopback_timer_stop_sync(dpcm); 765 mutex_lock(&loopback->cable_lock); 766 free_cable(substream); 767 mutex_unlock(&loopback->cable_lock); 768 return 0; 769 } 770 771 static const struct snd_pcm_ops loopback_pcm_ops = { 772 .open = loopback_open, 773 .close = loopback_close, 774 .ioctl = snd_pcm_lib_ioctl, 775 .hw_params = loopback_hw_params, 776 .hw_free = loopback_hw_free, 777 .prepare = loopback_prepare, 778 .trigger = loopback_trigger, 779 .pointer = loopback_pointer, 780 .page = snd_pcm_lib_get_vmalloc_page, 781 .mmap = snd_pcm_lib_mmap_vmalloc, 782 }; 783 784 static int loopback_pcm_new(struct loopback *loopback, 785 int device, int substreams) 786 { 787 struct snd_pcm *pcm; 788 int err; 789 790 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 791 substreams, substreams, &pcm); 792 if (err < 0) 793 return err; 794 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops); 795 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops); 796 797 pcm->private_data = loopback; 798 pcm->info_flags = 0; 799 strcpy(pcm->name, "Loopback PCM"); 800 801 loopback->pcm[device] = pcm; 802 return 0; 803 } 804 805 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 806 struct snd_ctl_elem_info *uinfo) 807 { 808 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 809 uinfo->count = 1; 810 uinfo->value.integer.min = 80000; 811 uinfo->value.integer.max = 120000; 812 uinfo->value.integer.step = 1; 813 return 0; 814 } 815 816 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 817 struct snd_ctl_elem_value *ucontrol) 818 { 819 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 820 821 mutex_lock(&loopback->cable_lock); 822 ucontrol->value.integer.value[0] = 823 loopback->setup[kcontrol->id.subdevice] 824 [kcontrol->id.device].rate_shift; 825 mutex_unlock(&loopback->cable_lock); 826 return 0; 827 } 828 829 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 830 struct snd_ctl_elem_value *ucontrol) 831 { 832 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 833 unsigned int val; 834 int change = 0; 835 836 val = ucontrol->value.integer.value[0]; 837 if (val < 80000) 838 val = 80000; 839 if (val > 120000) 840 val = 120000; 841 mutex_lock(&loopback->cable_lock); 842 if (val != loopback->setup[kcontrol->id.subdevice] 843 [kcontrol->id.device].rate_shift) { 844 loopback->setup[kcontrol->id.subdevice] 845 [kcontrol->id.device].rate_shift = val; 846 change = 1; 847 } 848 mutex_unlock(&loopback->cable_lock); 849 return change; 850 } 851 852 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 853 struct snd_ctl_elem_value *ucontrol) 854 { 855 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 856 857 mutex_lock(&loopback->cable_lock); 858 ucontrol->value.integer.value[0] = 859 loopback->setup[kcontrol->id.subdevice] 860 [kcontrol->id.device].notify; 861 mutex_unlock(&loopback->cable_lock); 862 return 0; 863 } 864 865 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 866 struct snd_ctl_elem_value *ucontrol) 867 { 868 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 869 unsigned int val; 870 int change = 0; 871 872 val = ucontrol->value.integer.value[0] ? 1 : 0; 873 mutex_lock(&loopback->cable_lock); 874 if (val != loopback->setup[kcontrol->id.subdevice] 875 [kcontrol->id.device].notify) { 876 loopback->setup[kcontrol->id.subdevice] 877 [kcontrol->id.device].notify = val; 878 change = 1; 879 } 880 mutex_unlock(&loopback->cable_lock); 881 return change; 882 } 883 884 static int loopback_active_get(struct snd_kcontrol *kcontrol, 885 struct snd_ctl_elem_value *ucontrol) 886 { 887 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 888 struct loopback_cable *cable; 889 890 unsigned int val = 0; 891 892 mutex_lock(&loopback->cable_lock); 893 cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 894 if (cable != NULL) { 895 unsigned int running = cable->running ^ cable->pause; 896 897 val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0; 898 } 899 mutex_unlock(&loopback->cable_lock); 900 ucontrol->value.integer.value[0] = val; 901 return 0; 902 } 903 904 static int loopback_format_info(struct snd_kcontrol *kcontrol, 905 struct snd_ctl_elem_info *uinfo) 906 { 907 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 908 uinfo->count = 1; 909 uinfo->value.integer.min = 0; 910 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 911 uinfo->value.integer.step = 1; 912 return 0; 913 } 914 915 static int loopback_format_get(struct snd_kcontrol *kcontrol, 916 struct snd_ctl_elem_value *ucontrol) 917 { 918 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 919 920 ucontrol->value.integer.value[0] = 921 loopback->setup[kcontrol->id.subdevice] 922 [kcontrol->id.device].format; 923 return 0; 924 } 925 926 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 927 struct snd_ctl_elem_info *uinfo) 928 { 929 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 930 uinfo->count = 1; 931 uinfo->value.integer.min = 0; 932 uinfo->value.integer.max = 192000; 933 uinfo->value.integer.step = 1; 934 return 0; 935 } 936 937 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 938 struct snd_ctl_elem_value *ucontrol) 939 { 940 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 941 942 mutex_lock(&loopback->cable_lock); 943 ucontrol->value.integer.value[0] = 944 loopback->setup[kcontrol->id.subdevice] 945 [kcontrol->id.device].rate; 946 mutex_unlock(&loopback->cable_lock); 947 return 0; 948 } 949 950 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 951 struct snd_ctl_elem_info *uinfo) 952 { 953 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 954 uinfo->count = 1; 955 uinfo->value.integer.min = 1; 956 uinfo->value.integer.max = 1024; 957 uinfo->value.integer.step = 1; 958 return 0; 959 } 960 961 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 962 struct snd_ctl_elem_value *ucontrol) 963 { 964 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 965 966 mutex_lock(&loopback->cable_lock); 967 ucontrol->value.integer.value[0] = 968 loopback->setup[kcontrol->id.subdevice] 969 [kcontrol->id.device].channels; 970 mutex_unlock(&loopback->cable_lock); 971 return 0; 972 } 973 974 static struct snd_kcontrol_new loopback_controls[] = { 975 { 976 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 977 .name = "PCM Rate Shift 100000", 978 .info = loopback_rate_shift_info, 979 .get = loopback_rate_shift_get, 980 .put = loopback_rate_shift_put, 981 }, 982 { 983 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 984 .name = "PCM Notify", 985 .info = snd_ctl_boolean_mono_info, 986 .get = loopback_notify_get, 987 .put = loopback_notify_put, 988 }, 989 #define ACTIVE_IDX 2 990 { 991 .access = SNDRV_CTL_ELEM_ACCESS_READ, 992 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 993 .name = "PCM Slave Active", 994 .info = snd_ctl_boolean_mono_info, 995 .get = loopback_active_get, 996 }, 997 #define FORMAT_IDX 3 998 { 999 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1000 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1001 .name = "PCM Slave Format", 1002 .info = loopback_format_info, 1003 .get = loopback_format_get 1004 }, 1005 #define RATE_IDX 4 1006 { 1007 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1008 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1009 .name = "PCM Slave Rate", 1010 .info = loopback_rate_info, 1011 .get = loopback_rate_get 1012 }, 1013 #define CHANNELS_IDX 5 1014 { 1015 .access = SNDRV_CTL_ELEM_ACCESS_READ, 1016 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 1017 .name = "PCM Slave Channels", 1018 .info = loopback_channels_info, 1019 .get = loopback_channels_get 1020 } 1021 }; 1022 1023 static int loopback_mixer_new(struct loopback *loopback, int notify) 1024 { 1025 struct snd_card *card = loopback->card; 1026 struct snd_pcm *pcm; 1027 struct snd_kcontrol *kctl; 1028 struct loopback_setup *setup; 1029 int err, dev, substr, substr_count, idx; 1030 1031 strcpy(card->mixername, "Loopback Mixer"); 1032 for (dev = 0; dev < 2; dev++) { 1033 pcm = loopback->pcm[dev]; 1034 substr_count = 1035 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1036 for (substr = 0; substr < substr_count; substr++) { 1037 setup = &loopback->setup[substr][dev]; 1038 setup->notify = notify; 1039 setup->rate_shift = NO_PITCH; 1040 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1041 setup->rate = 48000; 1042 setup->channels = 2; 1043 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1044 idx++) { 1045 kctl = snd_ctl_new1(&loopback_controls[idx], 1046 loopback); 1047 if (!kctl) 1048 return -ENOMEM; 1049 kctl->id.device = dev; 1050 kctl->id.subdevice = substr; 1051 switch (idx) { 1052 case ACTIVE_IDX: 1053 setup->active_id = kctl->id; 1054 break; 1055 case FORMAT_IDX: 1056 setup->format_id = kctl->id; 1057 break; 1058 case RATE_IDX: 1059 setup->rate_id = kctl->id; 1060 break; 1061 case CHANNELS_IDX: 1062 setup->channels_id = kctl->id; 1063 break; 1064 default: 1065 break; 1066 } 1067 err = snd_ctl_add(card, kctl); 1068 if (err < 0) 1069 return err; 1070 } 1071 } 1072 } 1073 return 0; 1074 } 1075 1076 static void print_dpcm_info(struct snd_info_buffer *buffer, 1077 struct loopback_pcm *dpcm, 1078 const char *id) 1079 { 1080 snd_iprintf(buffer, " %s\n", id); 1081 if (dpcm == NULL) { 1082 snd_iprintf(buffer, " inactive\n"); 1083 return; 1084 } 1085 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1086 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1087 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1088 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1089 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1090 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1091 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1092 snd_iprintf(buffer, " update_pending:\t%u\n", 1093 dpcm->period_update_pending); 1094 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1095 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1096 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1097 dpcm->last_jiffies, jiffies); 1098 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1099 } 1100 1101 static void print_substream_info(struct snd_info_buffer *buffer, 1102 struct loopback *loopback, 1103 int sub, 1104 int num) 1105 { 1106 struct loopback_cable *cable = loopback->cables[sub][num]; 1107 1108 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1109 if (cable == NULL) { 1110 snd_iprintf(buffer, " inactive\n"); 1111 return; 1112 } 1113 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1114 snd_iprintf(buffer, " running: %u\n", cable->running); 1115 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1116 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1117 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1118 } 1119 1120 static void print_cable_info(struct snd_info_entry *entry, 1121 struct snd_info_buffer *buffer) 1122 { 1123 struct loopback *loopback = entry->private_data; 1124 int sub, num; 1125 1126 mutex_lock(&loopback->cable_lock); 1127 num = entry->name[strlen(entry->name)-1]; 1128 num = num == '0' ? 0 : 1; 1129 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1130 print_substream_info(buffer, loopback, sub, num); 1131 mutex_unlock(&loopback->cable_lock); 1132 } 1133 1134 static int loopback_proc_new(struct loopback *loopback, int cidx) 1135 { 1136 char name[32]; 1137 struct snd_info_entry *entry; 1138 int err; 1139 1140 snprintf(name, sizeof(name), "cable#%d", cidx); 1141 err = snd_card_proc_new(loopback->card, name, &entry); 1142 if (err < 0) 1143 return err; 1144 1145 snd_info_set_text_ops(entry, loopback, print_cable_info); 1146 return 0; 1147 } 1148 1149 static int loopback_probe(struct platform_device *devptr) 1150 { 1151 struct snd_card *card; 1152 struct loopback *loopback; 1153 int dev = devptr->id; 1154 int err; 1155 1156 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE, 1157 sizeof(struct loopback), &card); 1158 if (err < 0) 1159 return err; 1160 loopback = card->private_data; 1161 1162 if (pcm_substreams[dev] < 1) 1163 pcm_substreams[dev] = 1; 1164 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1165 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1166 1167 loopback->card = card; 1168 mutex_init(&loopback->cable_lock); 1169 1170 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1171 if (err < 0) 1172 goto __nodev; 1173 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1174 if (err < 0) 1175 goto __nodev; 1176 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1177 if (err < 0) 1178 goto __nodev; 1179 loopback_proc_new(loopback, 0); 1180 loopback_proc_new(loopback, 1); 1181 strcpy(card->driver, "Loopback"); 1182 strcpy(card->shortname, "Loopback"); 1183 sprintf(card->longname, "Loopback %i", dev + 1); 1184 err = snd_card_register(card); 1185 if (!err) { 1186 platform_set_drvdata(devptr, card); 1187 return 0; 1188 } 1189 __nodev: 1190 snd_card_free(card); 1191 return err; 1192 } 1193 1194 static int loopback_remove(struct platform_device *devptr) 1195 { 1196 snd_card_free(platform_get_drvdata(devptr)); 1197 return 0; 1198 } 1199 1200 #ifdef CONFIG_PM_SLEEP 1201 static int loopback_suspend(struct device *pdev) 1202 { 1203 struct snd_card *card = dev_get_drvdata(pdev); 1204 struct loopback *loopback = card->private_data; 1205 1206 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1207 1208 snd_pcm_suspend_all(loopback->pcm[0]); 1209 snd_pcm_suspend_all(loopback->pcm[1]); 1210 return 0; 1211 } 1212 1213 static int loopback_resume(struct device *pdev) 1214 { 1215 struct snd_card *card = dev_get_drvdata(pdev); 1216 1217 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1218 return 0; 1219 } 1220 1221 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1222 #define LOOPBACK_PM_OPS &loopback_pm 1223 #else 1224 #define LOOPBACK_PM_OPS NULL 1225 #endif 1226 1227 #define SND_LOOPBACK_DRIVER "snd_aloop" 1228 1229 static struct platform_driver loopback_driver = { 1230 .probe = loopback_probe, 1231 .remove = loopback_remove, 1232 .driver = { 1233 .name = SND_LOOPBACK_DRIVER, 1234 .pm = LOOPBACK_PM_OPS, 1235 }, 1236 }; 1237 1238 static void loopback_unregister_all(void) 1239 { 1240 int i; 1241 1242 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1243 platform_device_unregister(devices[i]); 1244 platform_driver_unregister(&loopback_driver); 1245 } 1246 1247 static int __init alsa_card_loopback_init(void) 1248 { 1249 int i, err, cards; 1250 1251 err = platform_driver_register(&loopback_driver); 1252 if (err < 0) 1253 return err; 1254 1255 1256 cards = 0; 1257 for (i = 0; i < SNDRV_CARDS; i++) { 1258 struct platform_device *device; 1259 if (!enable[i]) 1260 continue; 1261 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1262 i, NULL, 0); 1263 if (IS_ERR(device)) 1264 continue; 1265 if (!platform_get_drvdata(device)) { 1266 platform_device_unregister(device); 1267 continue; 1268 } 1269 devices[i] = device; 1270 cards++; 1271 } 1272 if (!cards) { 1273 #ifdef MODULE 1274 printk(KERN_ERR "aloop: No loopback enabled\n"); 1275 #endif 1276 loopback_unregister_all(); 1277 return -ENODEV; 1278 } 1279 return 0; 1280 } 1281 1282 static void __exit alsa_card_loopback_exit(void) 1283 { 1284 loopback_unregister_all(); 1285 } 1286 1287 module_init(alsa_card_loopback_init) 1288 module_exit(alsa_card_loopback_exit) 1289