xref: /linux/sound/usb/pcm.c (revision c65c3f3a2cbf21ed429d9b9c725bdb5dc6abf4cf)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/init.h>
6 #include <linux/slab.h>
7 #include <linux/bitrev.h>
8 #include <linux/ratelimit.h>
9 #include <linux/usb.h>
10 #include <linux/usb/audio.h>
11 #include <linux/usb/audio-v2.h>
12 
13 #include <sound/core.h>
14 #include <sound/pcm.h>
15 #include <sound/pcm_params.h>
16 
17 #include "usbaudio.h"
18 #include "card.h"
19 #include "quirks.h"
20 #include "endpoint.h"
21 #include "helper.h"
22 #include "pcm.h"
23 #include "clock.h"
24 #include "power.h"
25 #include "media.h"
26 #include "implicit.h"
27 
28 #define SUBSTREAM_FLAG_DATA_EP_STARTED	0
29 #define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
30 
31 /* return the estimated delay based on USB frame counters */
32 static snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
33 					   struct snd_pcm_runtime *runtime)
34 {
35 	unsigned int current_frame_number;
36 	unsigned int frame_diff;
37 	int est_delay;
38 	int queued;
39 
40 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
41 		queued = bytes_to_frames(runtime, subs->inflight_bytes);
42 		if (!queued)
43 			return 0;
44 	} else if (!subs->running) {
45 		return 0;
46 	}
47 
48 	current_frame_number = usb_get_current_frame_number(subs->dev);
49 	/*
50 	 * HCD implementations use different widths, use lower 8 bits.
51 	 * The delay will be managed up to 256ms, which is more than
52 	 * enough
53 	 */
54 	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
55 
56 	/* Approximation based on number of samples per USB frame (ms),
57 	   some truncation for 44.1 but the estimate is good enough */
58 	est_delay = frame_diff * runtime->rate / 1000;
59 
60 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
61 		est_delay = queued - est_delay;
62 		if (est_delay < 0)
63 			est_delay = 0;
64 	}
65 
66 	return est_delay;
67 }
68 
69 /*
70  * return the current pcm pointer.  just based on the hwptr_done value.
71  */
72 static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
73 {
74 	struct snd_pcm_runtime *runtime = substream->runtime;
75 	struct snd_usb_substream *subs = runtime->private_data;
76 	unsigned int hwptr_done;
77 
78 	if (atomic_read(&subs->stream->chip->shutdown))
79 		return SNDRV_PCM_POS_XRUN;
80 	spin_lock(&subs->lock);
81 	hwptr_done = subs->hwptr_done;
82 	runtime->delay = snd_usb_pcm_delay(subs, runtime);
83 	spin_unlock(&subs->lock);
84 	return bytes_to_frames(runtime, hwptr_done);
85 }
86 
87 /*
88  * find a matching audio format
89  */
90 static const struct audioformat *
91 find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,
92 	    unsigned int rate, unsigned int channels, bool strict_match,
93 	    struct snd_usb_substream *subs)
94 {
95 	const struct audioformat *fp;
96 	const struct audioformat *found = NULL;
97 	int cur_attr = 0, attr;
98 
99 	list_for_each_entry(fp, fmt_list_head, list) {
100 		if (strict_match) {
101 			if (!(fp->formats & pcm_format_to_bits(format)))
102 				continue;
103 			if (fp->channels != channels)
104 				continue;
105 		}
106 		if (rate < fp->rate_min || rate > fp->rate_max)
107 			continue;
108 		if (!(fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
109 			unsigned int i;
110 			for (i = 0; i < fp->nr_rates; i++)
111 				if (fp->rate_table[i] == rate)
112 					break;
113 			if (i >= fp->nr_rates)
114 				continue;
115 		}
116 		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
117 		if (!found) {
118 			found = fp;
119 			cur_attr = attr;
120 			continue;
121 		}
122 		/* avoid async out and adaptive in if the other method
123 		 * supports the same format.
124 		 * this is a workaround for the case like
125 		 * M-audio audiophile USB.
126 		 */
127 		if (subs && attr != cur_attr) {
128 			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
129 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
130 			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
131 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
132 				continue;
133 			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
134 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
135 			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
136 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
137 				found = fp;
138 				cur_attr = attr;
139 				continue;
140 			}
141 		}
142 		/* find the format with the largest max. packet size */
143 		if (fp->maxpacksize > found->maxpacksize) {
144 			found = fp;
145 			cur_attr = attr;
146 		}
147 	}
148 	return found;
149 }
150 
151 static const struct audioformat *
152 find_substream_format(struct snd_usb_substream *subs,
153 		      const struct snd_pcm_hw_params *params)
154 {
155 	return find_format(&subs->fmt_list, params_format(params),
156 			   params_rate(params), params_channels(params),
157 			   true, subs);
158 }
159 
160 static int init_pitch_v1(struct snd_usb_audio *chip, int ep)
161 {
162 	struct usb_device *dev = chip->dev;
163 	unsigned char data[1];
164 	int err;
165 
166 	data[0] = 1;
167 	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
168 			      USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
169 			      UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
170 			      data, sizeof(data));
171 	return err;
172 }
173 
174 static int init_pitch_v2(struct snd_usb_audio *chip, int ep)
175 {
176 	struct usb_device *dev = chip->dev;
177 	unsigned char data[1];
178 	int err;
179 
180 	data[0] = 1;
181 	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
182 			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
183 			      UAC2_EP_CS_PITCH << 8, 0,
184 			      data, sizeof(data));
185 	return err;
186 }
187 
188 /*
189  * initialize the pitch control and sample rate
190  */
191 int snd_usb_init_pitch(struct snd_usb_audio *chip,
192 		       const struct audioformat *fmt)
193 {
194 	int err;
195 
196 	/* if endpoint doesn't have pitch control, bail out */
197 	if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
198 		return 0;
199 
200 	usb_audio_dbg(chip, "enable PITCH for EP 0x%x\n", fmt->endpoint);
201 
202 	switch (fmt->protocol) {
203 	case UAC_VERSION_1:
204 		err = init_pitch_v1(chip, fmt->endpoint);
205 		break;
206 	case UAC_VERSION_2:
207 		err = init_pitch_v2(chip, fmt->endpoint);
208 		break;
209 	default:
210 		return 0;
211 	}
212 
213 	if (err < 0) {
214 		usb_audio_err(chip, "failed to enable PITCH for EP 0x%x\n",
215 			      fmt->endpoint);
216 		return err;
217 	}
218 
219 	return 0;
220 }
221 
222 static bool stop_endpoints(struct snd_usb_substream *subs, bool keep_pending)
223 {
224 	bool stopped = 0;
225 
226 	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
227 		snd_usb_endpoint_stop(subs->sync_endpoint, keep_pending);
228 		stopped = true;
229 	}
230 	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
231 		snd_usb_endpoint_stop(subs->data_endpoint, keep_pending);
232 		stopped = true;
233 	}
234 	return stopped;
235 }
236 
237 static int start_endpoints(struct snd_usb_substream *subs)
238 {
239 	int err;
240 
241 	if (!subs->data_endpoint)
242 		return -EINVAL;
243 
244 	if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
245 		err = snd_usb_endpoint_start(subs->data_endpoint);
246 		if (err < 0) {
247 			clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
248 			goto error;
249 		}
250 	}
251 
252 	if (subs->sync_endpoint &&
253 	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
254 		err = snd_usb_endpoint_start(subs->sync_endpoint);
255 		if (err < 0) {
256 			clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
257 			goto error;
258 		}
259 	}
260 
261 	return 0;
262 
263  error:
264 	stop_endpoints(subs, false);
265 	return err;
266 }
267 
268 static void sync_pending_stops(struct snd_usb_substream *subs)
269 {
270 	snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
271 	snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
272 }
273 
274 /* PCM sync_stop callback */
275 static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
276 {
277 	struct snd_usb_substream *subs = substream->runtime->private_data;
278 
279 	sync_pending_stops(subs);
280 	return 0;
281 }
282 
283 /* Set up sync endpoint */
284 int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip,
285 				    struct audioformat *fmt)
286 {
287 	struct usb_device *dev = chip->dev;
288 	struct usb_host_interface *alts;
289 	struct usb_interface_descriptor *altsd;
290 	unsigned int ep, attr, sync_attr;
291 	bool is_playback;
292 	int err;
293 
294 	if (fmt->sync_ep)
295 		return 0; /* already set up */
296 
297 	alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
298 	if (!alts)
299 		return 0;
300 	altsd = get_iface_desc(alts);
301 
302 	err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
303 	if (err > 0)
304 		return 0; /* matched */
305 
306 	/*
307 	 * Generic sync EP handling
308 	 */
309 
310 	if (fmt->ep_idx > 0 || altsd->bNumEndpoints < 2)
311 		return 0;
312 
313 	is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
314 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
315 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
316 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
317 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
318 		return 0;
319 
320 	sync_attr = get_endpoint(alts, 1)->bmAttributes;
321 
322 	/*
323 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
324 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
325 	 * error fall back to SYNC mode and don't create sync endpoint
326 	 */
327 
328 	/* check sync-pipe endpoint */
329 	/* ... and check descriptor size before accessing bSynchAddress
330 	   because there is a version of the SB Audigy 2 NX firmware lacking
331 	   the audio fields in the endpoint descriptors */
332 	if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
333 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
334 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
335 		dev_err(&dev->dev,
336 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
337 			   fmt->iface, fmt->altsetting,
338 			   get_endpoint(alts, 1)->bmAttributes,
339 			   get_endpoint(alts, 1)->bLength,
340 			   get_endpoint(alts, 1)->bSynchAddress);
341 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
342 			return 0;
343 		return -EINVAL;
344 	}
345 	ep = get_endpoint(alts, 1)->bEndpointAddress;
346 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
347 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
348 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
349 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
350 		dev_err(&dev->dev,
351 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
352 			   fmt->iface, fmt->altsetting,
353 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
354 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
355 			return 0;
356 		return -EINVAL;
357 	}
358 
359 	fmt->sync_ep = ep;
360 	fmt->sync_iface = altsd->bInterfaceNumber;
361 	fmt->sync_altsetting = altsd->bAlternateSetting;
362 	fmt->sync_ep_idx = 1;
363 	if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
364 		fmt->implicit_fb = 1;
365 
366 	dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
367 		fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
368 		fmt->sync_altsetting, fmt->implicit_fb);
369 
370 	return 0;
371 }
372 
373 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
374 {
375 	int ret;
376 
377 	if (!subs->str_pd)
378 		return 0;
379 
380 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
381 	if (ret < 0) {
382 		dev_err(&subs->dev->dev,
383 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
384 			subs->str_pd->pd_id, state, ret);
385 		return ret;
386 	}
387 
388 	return 0;
389 }
390 
391 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
392 {
393 	int ret;
394 
395 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
396 	if (ret < 0)
397 		return ret;
398 
399 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
400 	if (ret < 0)
401 		return ret;
402 
403 	return 0;
404 }
405 
406 int snd_usb_pcm_resume(struct snd_usb_stream *as)
407 {
408 	int ret;
409 
410 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
411 	if (ret < 0)
412 		return ret;
413 
414 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
415 	if (ret < 0)
416 		return ret;
417 
418 	return 0;
419 }
420 
421 static void close_endpoints(struct snd_usb_audio *chip,
422 			    struct snd_usb_substream *subs)
423 {
424 	if (subs->data_endpoint) {
425 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
426 		snd_usb_endpoint_close(chip, subs->data_endpoint);
427 		subs->data_endpoint = NULL;
428 	}
429 
430 	if (subs->sync_endpoint) {
431 		snd_usb_endpoint_close(chip, subs->sync_endpoint);
432 		subs->sync_endpoint = NULL;
433 	}
434 }
435 
436 static int configure_endpoints(struct snd_usb_audio *chip,
437 			       struct snd_usb_substream *subs)
438 {
439 	int err;
440 
441 	if (subs->data_endpoint->need_setup) {
442 		/* stop any running stream beforehand */
443 		if (stop_endpoints(subs, false))
444 			sync_pending_stops(subs);
445 		if (subs->sync_endpoint) {
446 			err = snd_usb_endpoint_configure(chip, subs->sync_endpoint);
447 			if (err < 0)
448 				return err;
449 		}
450 		err = snd_usb_endpoint_configure(chip, subs->data_endpoint);
451 		if (err < 0)
452 			return err;
453 		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
454 	} else {
455 		if (subs->sync_endpoint) {
456 			err = snd_usb_endpoint_configure(chip, subs->sync_endpoint);
457 			if (err < 0)
458 				return err;
459 		}
460 	}
461 
462 	return 0;
463 }
464 
465 /*
466  * hw_params callback
467  *
468  * allocate a buffer and set the given audio format.
469  *
470  * so far we use a physically linear buffer although packetize transfer
471  * doesn't need a continuous area.
472  * if sg buffer is supported on the later version of alsa, we'll follow
473  * that.
474  */
475 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
476 			     struct snd_pcm_hw_params *hw_params)
477 {
478 	struct snd_usb_substream *subs = substream->runtime->private_data;
479 	struct snd_usb_audio *chip = subs->stream->chip;
480 	const struct audioformat *fmt;
481 	const struct audioformat *sync_fmt;
482 	int ret;
483 
484 	ret = snd_media_start_pipeline(subs);
485 	if (ret)
486 		return ret;
487 
488 	fmt = find_substream_format(subs, hw_params);
489 	if (!fmt) {
490 		usb_audio_dbg(chip,
491 			      "cannot find format: format=%s, rate=%d, channels=%d\n",
492 			      snd_pcm_format_name(params_format(hw_params)),
493 			      params_rate(hw_params), params_channels(hw_params));
494 		ret = -EINVAL;
495 		goto stop_pipeline;
496 	}
497 
498 	if (fmt->implicit_fb) {
499 		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
500 								hw_params,
501 								!substream->stream);
502 		if (!sync_fmt) {
503 			usb_audio_dbg(chip,
504 				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
505 				      fmt->sync_ep, fmt->sync_iface,
506 				      fmt->sync_altsetting,
507 				      snd_pcm_format_name(params_format(hw_params)),
508 				      params_rate(hw_params), params_channels(hw_params));
509 			ret = -EINVAL;
510 			goto stop_pipeline;
511 		}
512 	} else {
513 		sync_fmt = fmt;
514 	}
515 
516 	ret = snd_usb_lock_shutdown(chip);
517 	if (ret < 0)
518 		goto stop_pipeline;
519 
520 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
521 	if (ret < 0)
522 		goto unlock;
523 
524 	if (subs->data_endpoint) {
525 		if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
526 						fmt, hw_params))
527 			goto unlock;
528 		close_endpoints(chip, subs);
529 	}
530 
531 	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false);
532 	if (!subs->data_endpoint) {
533 		ret = -EINVAL;
534 		goto unlock;
535 	}
536 
537 	if (fmt->sync_ep) {
538 		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
539 							    hw_params,
540 							    fmt == sync_fmt);
541 		if (!subs->sync_endpoint) {
542 			ret = -EINVAL;
543 			goto unlock;
544 		}
545 
546 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
547 					  subs->sync_endpoint);
548 	}
549 
550 	mutex_lock(&chip->mutex);
551 	subs->cur_audiofmt = fmt;
552 	mutex_unlock(&chip->mutex);
553 
554 	ret = configure_endpoints(chip, subs);
555 
556  unlock:
557 	if (ret < 0)
558 		close_endpoints(chip, subs);
559 
560 	snd_usb_unlock_shutdown(chip);
561  stop_pipeline:
562 	if (ret < 0)
563 		snd_media_stop_pipeline(subs);
564 
565 	return ret;
566 }
567 
568 /*
569  * hw_free callback
570  *
571  * reset the audio format and release the buffer
572  */
573 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
574 {
575 	struct snd_usb_substream *subs = substream->runtime->private_data;
576 	struct snd_usb_audio *chip = subs->stream->chip;
577 
578 	snd_media_stop_pipeline(subs);
579 	mutex_lock(&chip->mutex);
580 	subs->cur_audiofmt = NULL;
581 	mutex_unlock(&chip->mutex);
582 	if (!snd_usb_lock_shutdown(chip)) {
583 		if (stop_endpoints(subs, false))
584 			sync_pending_stops(subs);
585 		close_endpoints(chip, subs);
586 		snd_usb_unlock_shutdown(chip);
587 	}
588 
589 	return 0;
590 }
591 
592 /* free-wheeling mode? (e.g. dmix) */
593 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
594 {
595 	return runtime->stop_threshold > runtime->buffer_size;
596 }
597 
598 /* check whether early start is needed for playback stream */
599 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
600 					 struct snd_usb_substream *subs)
601 {
602 	struct snd_usb_audio *chip = subs->stream->chip;
603 
604 	if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
605 		return false;
606 	/* disabled via module option? */
607 	if (!chip->lowlatency)
608 		return false;
609 	if (in_free_wheeling_mode(runtime))
610 		return false;
611 	/* implicit feedback mode has own operation mode */
612 	if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
613 		return false;
614 	return true;
615 }
616 
617 /*
618  * prepare callback
619  *
620  * only a few subtle things...
621  */
622 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
623 {
624 	struct snd_pcm_runtime *runtime = substream->runtime;
625 	struct snd_usb_substream *subs = runtime->private_data;
626 	struct snd_usb_audio *chip = subs->stream->chip;
627 	int ret;
628 
629 	ret = snd_usb_lock_shutdown(chip);
630 	if (ret < 0)
631 		return ret;
632 	if (snd_BUG_ON(!subs->data_endpoint)) {
633 		ret = -EIO;
634 		goto unlock;
635 	}
636 
637 	ret = configure_endpoints(chip, subs);
638 	if (ret < 0)
639 		goto unlock;
640 
641 	/* reset the pointer */
642 	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
643 	subs->inflight_bytes = 0;
644 	subs->hwptr_done = 0;
645 	subs->transfer_done = 0;
646 	subs->last_frame_number = 0;
647 	subs->period_elapsed_pending = 0;
648 	runtime->delay = 0;
649 
650 	subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
651 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
652 	    !subs->lowlatency_playback)
653 		ret = start_endpoints(subs);
654 
655  unlock:
656 	snd_usb_unlock_shutdown(chip);
657 	return ret;
658 }
659 
660 /*
661  * h/w constraints
662  */
663 
664 #ifdef HW_CONST_DEBUG
665 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
666 #else
667 #define hwc_debug(fmt, args...) do { } while(0)
668 #endif
669 
670 static const struct snd_pcm_hardware snd_usb_hardware =
671 {
672 	.info =			SNDRV_PCM_INFO_MMAP |
673 				SNDRV_PCM_INFO_MMAP_VALID |
674 				SNDRV_PCM_INFO_BATCH |
675 				SNDRV_PCM_INFO_INTERLEAVED |
676 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
677 				SNDRV_PCM_INFO_PAUSE,
678 	.channels_min =		1,
679 	.channels_max =		256,
680 	.buffer_bytes_max =	INT_MAX, /* limited by BUFFER_TIME later */
681 	.period_bytes_min =	64,
682 	.period_bytes_max =	INT_MAX, /* limited by PERIOD_TIME later */
683 	.periods_min =		2,
684 	.periods_max =		1024,
685 };
686 
687 static int hw_check_valid_format(struct snd_usb_substream *subs,
688 				 struct snd_pcm_hw_params *params,
689 				 const struct audioformat *fp)
690 {
691 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
692 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
693 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
694 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
695 	struct snd_mask check_fmts;
696 	unsigned int ptime;
697 
698 	/* check the format */
699 	snd_mask_none(&check_fmts);
700 	check_fmts.bits[0] = (u32)fp->formats;
701 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
702 	snd_mask_intersect(&check_fmts, fmts);
703 	if (snd_mask_empty(&check_fmts)) {
704 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
705 		return 0;
706 	}
707 	/* check the channels */
708 	if (fp->channels < ct->min || fp->channels > ct->max) {
709 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
710 		return 0;
711 	}
712 	/* check the rate is within the range */
713 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
714 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
715 		return 0;
716 	}
717 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
718 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
719 		return 0;
720 	}
721 	/* check whether the period time is >= the data packet interval */
722 	if (subs->speed != USB_SPEED_FULL) {
723 		ptime = 125 * (1 << fp->datainterval);
724 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
725 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
726 			return 0;
727 		}
728 	}
729 	return 1;
730 }
731 
732 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
733 				  unsigned int rmax)
734 {
735 	int changed;
736 
737 	if (rmin > rmax) {
738 		hwc_debug("  --> get empty\n");
739 		it->empty = 1;
740 		return -EINVAL;
741 	}
742 
743 	changed = 0;
744 	if (it->min < rmin) {
745 		it->min = rmin;
746 		it->openmin = 0;
747 		changed = 1;
748 	}
749 	if (it->max > rmax) {
750 		it->max = rmax;
751 		it->openmax = 0;
752 		changed = 1;
753 	}
754 	if (snd_interval_checkempty(it)) {
755 		it->empty = 1;
756 		return -EINVAL;
757 	}
758 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
759 	return changed;
760 }
761 
762 static int hw_rule_rate(struct snd_pcm_hw_params *params,
763 			struct snd_pcm_hw_rule *rule)
764 {
765 	struct snd_usb_substream *subs = rule->private;
766 	struct snd_usb_audio *chip = subs->stream->chip;
767 	const struct audioformat *fp;
768 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
769 	unsigned int rmin, rmax, r;
770 	int i;
771 
772 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
773 	rmin = UINT_MAX;
774 	rmax = 0;
775 	list_for_each_entry(fp, &subs->fmt_list, list) {
776 		if (!hw_check_valid_format(subs, params, fp))
777 			continue;
778 		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
779 		if (r > 0) {
780 			if (!snd_interval_test(it, r))
781 				continue;
782 			rmin = min(rmin, r);
783 			rmax = max(rmax, r);
784 			continue;
785 		}
786 		if (fp->rate_table && fp->nr_rates) {
787 			for (i = 0; i < fp->nr_rates; i++) {
788 				r = fp->rate_table[i];
789 				if (!snd_interval_test(it, r))
790 					continue;
791 				rmin = min(rmin, r);
792 				rmax = max(rmax, r);
793 			}
794 		} else {
795 			rmin = min(rmin, fp->rate_min);
796 			rmax = max(rmax, fp->rate_max);
797 		}
798 	}
799 
800 	return apply_hw_params_minmax(it, rmin, rmax);
801 }
802 
803 
804 static int hw_rule_channels(struct snd_pcm_hw_params *params,
805 			    struct snd_pcm_hw_rule *rule)
806 {
807 	struct snd_usb_substream *subs = rule->private;
808 	const struct audioformat *fp;
809 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
810 	unsigned int rmin, rmax;
811 
812 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
813 	rmin = UINT_MAX;
814 	rmax = 0;
815 	list_for_each_entry(fp, &subs->fmt_list, list) {
816 		if (!hw_check_valid_format(subs, params, fp))
817 			continue;
818 		rmin = min(rmin, fp->channels);
819 		rmax = max(rmax, fp->channels);
820 	}
821 
822 	return apply_hw_params_minmax(it, rmin, rmax);
823 }
824 
825 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
826 {
827 	u32 oldbits[2];
828 	int changed;
829 
830 	oldbits[0] = fmt->bits[0];
831 	oldbits[1] = fmt->bits[1];
832 	fmt->bits[0] &= (u32)fbits;
833 	fmt->bits[1] &= (u32)(fbits >> 32);
834 	if (!fmt->bits[0] && !fmt->bits[1]) {
835 		hwc_debug("  --> get empty\n");
836 		return -EINVAL;
837 	}
838 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
839 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
840 	return changed;
841 }
842 
843 static int hw_rule_format(struct snd_pcm_hw_params *params,
844 			  struct snd_pcm_hw_rule *rule)
845 {
846 	struct snd_usb_substream *subs = rule->private;
847 	const struct audioformat *fp;
848 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
849 	u64 fbits;
850 
851 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
852 	fbits = 0;
853 	list_for_each_entry(fp, &subs->fmt_list, list) {
854 		if (!hw_check_valid_format(subs, params, fp))
855 			continue;
856 		fbits |= fp->formats;
857 	}
858 	return apply_hw_params_format_bits(fmt, fbits);
859 }
860 
861 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
862 			       struct snd_pcm_hw_rule *rule)
863 {
864 	struct snd_usb_substream *subs = rule->private;
865 	const struct audioformat *fp;
866 	struct snd_interval *it;
867 	unsigned char min_datainterval;
868 	unsigned int pmin;
869 
870 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
871 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
872 	min_datainterval = 0xff;
873 	list_for_each_entry(fp, &subs->fmt_list, list) {
874 		if (!hw_check_valid_format(subs, params, fp))
875 			continue;
876 		min_datainterval = min(min_datainterval, fp->datainterval);
877 	}
878 	if (min_datainterval == 0xff) {
879 		hwc_debug("  --> get empty\n");
880 		it->empty = 1;
881 		return -EINVAL;
882 	}
883 	pmin = 125 * (1 << min_datainterval);
884 
885 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
886 }
887 
888 /* get the EP or the sync EP for implicit fb when it's already set up */
889 static const struct snd_usb_endpoint *
890 get_sync_ep_from_substream(struct snd_usb_substream *subs)
891 {
892 	struct snd_usb_audio *chip = subs->stream->chip;
893 	const struct audioformat *fp;
894 	const struct snd_usb_endpoint *ep;
895 
896 	list_for_each_entry(fp, &subs->fmt_list, list) {
897 		ep = snd_usb_get_endpoint(chip, fp->endpoint);
898 		if (ep && ep->cur_audiofmt) {
899 			/* if EP is already opened solely for this substream,
900 			 * we still allow us to change the parameter; otherwise
901 			 * this substream has to follow the existing parameter
902 			 */
903 			if (ep->cur_audiofmt != subs->cur_audiofmt || ep->opened > 1)
904 				return ep;
905 		}
906 		if (!fp->implicit_fb)
907 			continue;
908 		/* for the implicit fb, check the sync ep as well */
909 		ep = snd_usb_get_endpoint(chip, fp->sync_ep);
910 		if (ep && ep->cur_audiofmt)
911 			return ep;
912 	}
913 	return NULL;
914 }
915 
916 /* additional hw constraints for implicit feedback mode */
917 static int hw_rule_format_implicit_fb(struct snd_pcm_hw_params *params,
918 				      struct snd_pcm_hw_rule *rule)
919 {
920 	struct snd_usb_substream *subs = rule->private;
921 	const struct snd_usb_endpoint *ep;
922 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
923 
924 	ep = get_sync_ep_from_substream(subs);
925 	if (!ep)
926 		return 0;
927 
928 	hwc_debug("applying %s\n", __func__);
929 	return apply_hw_params_format_bits(fmt, pcm_format_to_bits(ep->cur_format));
930 }
931 
932 static int hw_rule_rate_implicit_fb(struct snd_pcm_hw_params *params,
933 				    struct snd_pcm_hw_rule *rule)
934 {
935 	struct snd_usb_substream *subs = rule->private;
936 	const struct snd_usb_endpoint *ep;
937 	struct snd_interval *it;
938 
939 	ep = get_sync_ep_from_substream(subs);
940 	if (!ep)
941 		return 0;
942 
943 	hwc_debug("applying %s\n", __func__);
944 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
945 	return apply_hw_params_minmax(it, ep->cur_rate, ep->cur_rate);
946 }
947 
948 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
949 					   struct snd_pcm_hw_rule *rule)
950 {
951 	struct snd_usb_substream *subs = rule->private;
952 	const struct snd_usb_endpoint *ep;
953 	struct snd_interval *it;
954 
955 	ep = get_sync_ep_from_substream(subs);
956 	if (!ep)
957 		return 0;
958 
959 	hwc_debug("applying %s\n", __func__);
960 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
961 	return apply_hw_params_minmax(it, ep->cur_period_frames,
962 				      ep->cur_period_frames);
963 }
964 
965 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
966 				       struct snd_pcm_hw_rule *rule)
967 {
968 	struct snd_usb_substream *subs = rule->private;
969 	const struct snd_usb_endpoint *ep;
970 	struct snd_interval *it;
971 
972 	ep = get_sync_ep_from_substream(subs);
973 	if (!ep)
974 		return 0;
975 
976 	hwc_debug("applying %s\n", __func__);
977 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
978 	return apply_hw_params_minmax(it, ep->cur_buffer_periods,
979 				      ep->cur_buffer_periods);
980 }
981 
982 /*
983  * set up the runtime hardware information.
984  */
985 
986 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
987 {
988 	const struct audioformat *fp;
989 	unsigned int pt, ptmin;
990 	int param_period_time_if_needed = -1;
991 	int err;
992 
993 	runtime->hw.formats = subs->formats;
994 
995 	runtime->hw.rate_min = 0x7fffffff;
996 	runtime->hw.rate_max = 0;
997 	runtime->hw.channels_min = 256;
998 	runtime->hw.channels_max = 0;
999 	runtime->hw.rates = 0;
1000 	ptmin = UINT_MAX;
1001 	/* check min/max rates and channels */
1002 	list_for_each_entry(fp, &subs->fmt_list, list) {
1003 		runtime->hw.rates |= fp->rates;
1004 		if (runtime->hw.rate_min > fp->rate_min)
1005 			runtime->hw.rate_min = fp->rate_min;
1006 		if (runtime->hw.rate_max < fp->rate_max)
1007 			runtime->hw.rate_max = fp->rate_max;
1008 		if (runtime->hw.channels_min > fp->channels)
1009 			runtime->hw.channels_min = fp->channels;
1010 		if (runtime->hw.channels_max < fp->channels)
1011 			runtime->hw.channels_max = fp->channels;
1012 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1013 			/* FIXME: there might be more than one audio formats... */
1014 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1015 				fp->frame_size;
1016 		}
1017 		pt = 125 * (1 << fp->datainterval);
1018 		ptmin = min(ptmin, pt);
1019 	}
1020 
1021 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1022 	if (subs->speed == USB_SPEED_FULL)
1023 		/* full speed devices have fixed data packet interval */
1024 		ptmin = 1000;
1025 	if (ptmin == 1000)
1026 		/* if period time doesn't go below 1 ms, no rules needed */
1027 		param_period_time_if_needed = -1;
1028 
1029 	err = snd_pcm_hw_constraint_minmax(runtime,
1030 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1031 					   ptmin, UINT_MAX);
1032 	if (err < 0)
1033 		return err;
1034 
1035 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1036 				  hw_rule_rate, subs,
1037 				  SNDRV_PCM_HW_PARAM_RATE,
1038 				  SNDRV_PCM_HW_PARAM_FORMAT,
1039 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1040 				  param_period_time_if_needed,
1041 				  -1);
1042 	if (err < 0)
1043 		return err;
1044 
1045 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1046 				  hw_rule_channels, subs,
1047 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1048 				  SNDRV_PCM_HW_PARAM_FORMAT,
1049 				  SNDRV_PCM_HW_PARAM_RATE,
1050 				  param_period_time_if_needed,
1051 				  -1);
1052 	if (err < 0)
1053 		return err;
1054 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1055 				  hw_rule_format, subs,
1056 				  SNDRV_PCM_HW_PARAM_FORMAT,
1057 				  SNDRV_PCM_HW_PARAM_RATE,
1058 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1059 				  param_period_time_if_needed,
1060 				  -1);
1061 	if (err < 0)
1062 		return err;
1063 	if (param_period_time_if_needed >= 0) {
1064 		err = snd_pcm_hw_rule_add(runtime, 0,
1065 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1066 					  hw_rule_period_time, subs,
1067 					  SNDRV_PCM_HW_PARAM_FORMAT,
1068 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1069 					  SNDRV_PCM_HW_PARAM_RATE,
1070 					  -1);
1071 		if (err < 0)
1072 			return err;
1073 	}
1074 
1075 	/* set max period and buffer sizes for 1 and 2 seconds, respectively */
1076 	err = snd_pcm_hw_constraint_minmax(runtime,
1077 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1078 					   0, 1000000);
1079 	if (err < 0)
1080 		return err;
1081 	err = snd_pcm_hw_constraint_minmax(runtime,
1082 					   SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1083 					   0, 2000000);
1084 	if (err < 0)
1085 		return err;
1086 
1087 	/* additional hw constraints for implicit fb */
1088 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1089 				  hw_rule_format_implicit_fb, subs,
1090 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1091 	if (err < 0)
1092 		return err;
1093 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1094 				  hw_rule_rate_implicit_fb, subs,
1095 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1096 	if (err < 0)
1097 		return err;
1098 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1099 				  hw_rule_period_size_implicit_fb, subs,
1100 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1101 	if (err < 0)
1102 		return err;
1103 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1104 				  hw_rule_periods_implicit_fb, subs,
1105 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1106 	if (err < 0)
1107 		return err;
1108 
1109 	list_for_each_entry(fp, &subs->fmt_list, list) {
1110 		if (fp->implicit_fb) {
1111 			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1112 			break;
1113 		}
1114 	}
1115 
1116 	return 0;
1117 }
1118 
1119 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1120 {
1121 	int direction = substream->stream;
1122 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1123 	struct snd_pcm_runtime *runtime = substream->runtime;
1124 	struct snd_usb_substream *subs = &as->substream[direction];
1125 	int ret;
1126 
1127 	runtime->hw = snd_usb_hardware;
1128 	/* need an explicit sync to catch applptr update in low-latency mode */
1129 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1130 	    as->chip->lowlatency)
1131 		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1132 	runtime->private_data = subs;
1133 	subs->pcm_substream = substream;
1134 	/* runtime PM is also done there */
1135 
1136 	/* initialize DSD/DOP context */
1137 	subs->dsd_dop.byte_idx = 0;
1138 	subs->dsd_dop.channel = 0;
1139 	subs->dsd_dop.marker = 1;
1140 
1141 	ret = setup_hw_info(runtime, subs);
1142 	if (ret < 0)
1143 		return ret;
1144 	ret = snd_usb_autoresume(subs->stream->chip);
1145 	if (ret < 0)
1146 		return ret;
1147 	ret = snd_media_stream_init(subs, as->pcm, direction);
1148 	if (ret < 0)
1149 		snd_usb_autosuspend(subs->stream->chip);
1150 	return ret;
1151 }
1152 
1153 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1154 {
1155 	int direction = substream->stream;
1156 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1157 	struct snd_usb_substream *subs = &as->substream[direction];
1158 	int ret;
1159 
1160 	snd_media_stop_pipeline(subs);
1161 
1162 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1163 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1164 		snd_usb_unlock_shutdown(subs->stream->chip);
1165 		if (ret < 0)
1166 			return ret;
1167 	}
1168 
1169 	subs->pcm_substream = NULL;
1170 	snd_usb_autosuspend(subs->stream->chip);
1171 
1172 	return 0;
1173 }
1174 
1175 /* Since a URB can handle only a single linear buffer, we must use double
1176  * buffering when the data to be transferred overflows the buffer boundary.
1177  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1178  * for all URBs.
1179  */
1180 static void retire_capture_urb(struct snd_usb_substream *subs,
1181 			       struct urb *urb)
1182 {
1183 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1184 	unsigned int stride, frames, bytes, oldptr;
1185 	int i, period_elapsed = 0;
1186 	unsigned long flags;
1187 	unsigned char *cp;
1188 	int current_frame_number;
1189 
1190 	/* read frame number here, update pointer in critical section */
1191 	current_frame_number = usb_get_current_frame_number(subs->dev);
1192 
1193 	stride = runtime->frame_bits >> 3;
1194 
1195 	for (i = 0; i < urb->number_of_packets; i++) {
1196 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1197 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1198 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1199 				i, urb->iso_frame_desc[i].status);
1200 			// continue;
1201 		}
1202 		bytes = urb->iso_frame_desc[i].actual_length;
1203 		if (subs->stream_offset_adj > 0) {
1204 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1205 			cp += adj;
1206 			bytes -= adj;
1207 			subs->stream_offset_adj -= adj;
1208 		}
1209 		frames = bytes / stride;
1210 		if (!subs->txfr_quirk)
1211 			bytes = frames * stride;
1212 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1213 			int oldbytes = bytes;
1214 			bytes = frames * stride;
1215 			dev_warn_ratelimited(&subs->dev->dev,
1216 				 "Corrected urb data len. %d->%d\n",
1217 							oldbytes, bytes);
1218 		}
1219 		/* update the current pointer */
1220 		spin_lock_irqsave(&subs->lock, flags);
1221 		oldptr = subs->hwptr_done;
1222 		subs->hwptr_done += bytes;
1223 		if (subs->hwptr_done >= subs->buffer_bytes)
1224 			subs->hwptr_done -= subs->buffer_bytes;
1225 		frames = (bytes + (oldptr % stride)) / stride;
1226 		subs->transfer_done += frames;
1227 		if (subs->transfer_done >= runtime->period_size) {
1228 			subs->transfer_done -= runtime->period_size;
1229 			period_elapsed = 1;
1230 		}
1231 
1232 		/* realign last_frame_number */
1233 		subs->last_frame_number = current_frame_number;
1234 
1235 		spin_unlock_irqrestore(&subs->lock, flags);
1236 		/* copy a data chunk */
1237 		if (oldptr + bytes > subs->buffer_bytes) {
1238 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1239 
1240 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1241 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1242 		} else {
1243 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1244 		}
1245 	}
1246 
1247 	if (period_elapsed)
1248 		snd_pcm_period_elapsed(subs->pcm_substream);
1249 }
1250 
1251 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1252 				  struct urb *urb, unsigned int bytes)
1253 {
1254 	struct snd_urb_ctx *ctx = urb->context;
1255 
1256 	ctx->queued += bytes;
1257 	subs->inflight_bytes += bytes;
1258 	subs->hwptr_done += bytes;
1259 	if (subs->hwptr_done >= subs->buffer_bytes)
1260 		subs->hwptr_done -= subs->buffer_bytes;
1261 }
1262 
1263 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1264 					     struct urb *urb, unsigned int bytes)
1265 {
1266 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1267 	unsigned int dst_idx = 0;
1268 	unsigned int src_idx = subs->hwptr_done;
1269 	unsigned int wrap = subs->buffer_bytes;
1270 	u8 *dst = urb->transfer_buffer;
1271 	u8 *src = runtime->dma_area;
1272 	static const u8 marker[] = { 0x05, 0xfa };
1273 	unsigned int queued = 0;
1274 
1275 	/*
1276 	 * The DSP DOP format defines a way to transport DSD samples over
1277 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1278 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1279 	 * 2 additional bytes of actual payload. The whole frame is stored
1280 	 * LSB.
1281 	 *
1282 	 * Hence, for a stereo transport, the buffer layout looks like this,
1283 	 * where L refers to left channel samples and R to right.
1284 	 *
1285 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1286 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1287 	 *   .....
1288 	 *
1289 	 */
1290 
1291 	while (bytes--) {
1292 		if (++subs->dsd_dop.byte_idx == 3) {
1293 			/* frame boundary? */
1294 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1295 			src_idx += 2;
1296 			subs->dsd_dop.byte_idx = 0;
1297 
1298 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1299 				/* alternate the marker */
1300 				subs->dsd_dop.marker++;
1301 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1302 				subs->dsd_dop.channel = 0;
1303 			}
1304 		} else {
1305 			/* stuff the DSD payload */
1306 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1307 
1308 			if (subs->cur_audiofmt->dsd_bitrev)
1309 				dst[dst_idx++] = bitrev8(src[idx]);
1310 			else
1311 				dst[dst_idx++] = src[idx];
1312 			queued++;
1313 		}
1314 	}
1315 
1316 	urb_ctx_queue_advance(subs, urb, queued);
1317 }
1318 
1319 /* copy bit-reversed bytes onto transfer buffer */
1320 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1321 					 struct urb *urb, unsigned int bytes)
1322 {
1323 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1324 	const u8 *src = runtime->dma_area;
1325 	u8 *buf = urb->transfer_buffer;
1326 	int i, ofs = subs->hwptr_done;
1327 
1328 	for (i = 0; i < bytes; i++) {
1329 		*buf++ = bitrev8(src[ofs]);
1330 		if (++ofs >= subs->buffer_bytes)
1331 			ofs = 0;
1332 	}
1333 
1334 	urb_ctx_queue_advance(subs, urb, bytes);
1335 }
1336 
1337 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1338 			int offset, int stride, unsigned int bytes)
1339 {
1340 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1341 
1342 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1343 		/* err, the transferred area goes over buffer boundary. */
1344 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1345 
1346 		memcpy(urb->transfer_buffer + offset,
1347 		       runtime->dma_area + subs->hwptr_done, bytes1);
1348 		memcpy(urb->transfer_buffer + offset + bytes1,
1349 		       runtime->dma_area, bytes - bytes1);
1350 	} else {
1351 		memcpy(urb->transfer_buffer + offset,
1352 		       runtime->dma_area + subs->hwptr_done, bytes);
1353 	}
1354 
1355 	urb_ctx_queue_advance(subs, urb, bytes);
1356 }
1357 
1358 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1359 				      struct urb *urb, int stride,
1360 				      unsigned int bytes)
1361 {
1362 	__le32 packet_length;
1363 	int i;
1364 
1365 	/* Put __le32 length descriptor at start of each packet. */
1366 	for (i = 0; i < urb->number_of_packets; i++) {
1367 		unsigned int length = urb->iso_frame_desc[i].length;
1368 		unsigned int offset = urb->iso_frame_desc[i].offset;
1369 
1370 		packet_length = cpu_to_le32(length);
1371 		offset += i * sizeof(packet_length);
1372 		urb->iso_frame_desc[i].offset = offset;
1373 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1374 		memcpy(urb->transfer_buffer + offset,
1375 		       &packet_length, sizeof(packet_length));
1376 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1377 			    stride, length);
1378 	}
1379 	/* Adjust transfer size accordingly. */
1380 	bytes += urb->number_of_packets * sizeof(packet_length);
1381 	return bytes;
1382 }
1383 
1384 static int prepare_playback_urb(struct snd_usb_substream *subs,
1385 				struct urb *urb,
1386 				bool in_stream_lock)
1387 {
1388 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1389 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1390 	struct snd_urb_ctx *ctx = urb->context;
1391 	unsigned int frames, bytes;
1392 	int counts;
1393 	unsigned int transfer_done, frame_limit, avail = 0;
1394 	int i, stride, period_elapsed = 0;
1395 	unsigned long flags;
1396 	int err = 0;
1397 
1398 	stride = ep->stride;
1399 
1400 	frames = 0;
1401 	ctx->queued = 0;
1402 	urb->number_of_packets = 0;
1403 
1404 	spin_lock_irqsave(&subs->lock, flags);
1405 	frame_limit = subs->frame_limit + ep->max_urb_frames;
1406 	transfer_done = subs->transfer_done;
1407 
1408 	if (subs->lowlatency_playback &&
1409 	    runtime->status->state != SNDRV_PCM_STATE_DRAINING) {
1410 		unsigned int hwptr = subs->hwptr_done / stride;
1411 
1412 		/* calculate the byte offset-in-buffer of the appl_ptr */
1413 		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1414 			% runtime->buffer_size;
1415 		if (avail <= hwptr)
1416 			avail += runtime->buffer_size;
1417 		avail -= hwptr;
1418 	}
1419 
1420 	for (i = 0; i < ctx->packets; i++) {
1421 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1422 		if (counts < 0)
1423 			break;
1424 		/* set up descriptor */
1425 		urb->iso_frame_desc[i].offset = frames * stride;
1426 		urb->iso_frame_desc[i].length = counts * stride;
1427 		frames += counts;
1428 		avail -= counts;
1429 		urb->number_of_packets++;
1430 		transfer_done += counts;
1431 		if (transfer_done >= runtime->period_size) {
1432 			transfer_done -= runtime->period_size;
1433 			frame_limit = 0;
1434 			period_elapsed = 1;
1435 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1436 				if (transfer_done > 0) {
1437 					/* FIXME: fill-max mode is not
1438 					 * supported yet */
1439 					frames -= transfer_done;
1440 					counts -= transfer_done;
1441 					urb->iso_frame_desc[i].length =
1442 						counts * stride;
1443 					transfer_done = 0;
1444 				}
1445 				i++;
1446 				if (i < ctx->packets) {
1447 					/* add a transfer delimiter */
1448 					urb->iso_frame_desc[i].offset =
1449 						frames * stride;
1450 					urb->iso_frame_desc[i].length = 0;
1451 					urb->number_of_packets++;
1452 				}
1453 				break;
1454 			}
1455 		}
1456 		/* finish at the period boundary or after enough frames */
1457 		if ((period_elapsed || transfer_done >= frame_limit) &&
1458 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1459 			break;
1460 	}
1461 
1462 	if (!frames) {
1463 		err = -EAGAIN;
1464 		goto unlock;
1465 	}
1466 
1467 	bytes = frames * stride;
1468 	subs->transfer_done = transfer_done;
1469 	subs->frame_limit = frame_limit;
1470 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1471 		     subs->cur_audiofmt->dsd_dop)) {
1472 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1473 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1474 			   subs->cur_audiofmt->dsd_bitrev)) {
1475 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1476 	} else {
1477 		/* usual PCM */
1478 		if (!subs->tx_length_quirk)
1479 			copy_to_urb(subs, urb, 0, stride, bytes);
1480 		else
1481 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1482 			/* bytes is now amount of outgoing data */
1483 	}
1484 
1485 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1486 
1487 	if (subs->trigger_tstamp_pending_update) {
1488 		/* this is the first actual URB submitted,
1489 		 * update trigger timestamp to reflect actual start time
1490 		 */
1491 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1492 		subs->trigger_tstamp_pending_update = false;
1493 	}
1494 
1495 	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1496 		subs->period_elapsed_pending = 1;
1497 		period_elapsed = 0;
1498 	}
1499 
1500  unlock:
1501 	spin_unlock_irqrestore(&subs->lock, flags);
1502 	if (err < 0)
1503 		return err;
1504 	urb->transfer_buffer_length = bytes;
1505 	if (period_elapsed) {
1506 		if (in_stream_lock)
1507 			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1508 		else
1509 			snd_pcm_period_elapsed(subs->pcm_substream);
1510 	}
1511 	return 0;
1512 }
1513 
1514 /*
1515  * process after playback data complete
1516  * - decrease the delay count again
1517  */
1518 static void retire_playback_urb(struct snd_usb_substream *subs,
1519 			       struct urb *urb)
1520 {
1521 	unsigned long flags;
1522 	struct snd_urb_ctx *ctx = urb->context;
1523 	bool period_elapsed = false;
1524 
1525 	spin_lock_irqsave(&subs->lock, flags);
1526 	if (ctx->queued) {
1527 		if (subs->inflight_bytes >= ctx->queued)
1528 			subs->inflight_bytes -= ctx->queued;
1529 		else
1530 			subs->inflight_bytes = 0;
1531 	}
1532 
1533 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1534 	if (subs->running) {
1535 		period_elapsed = subs->period_elapsed_pending;
1536 		subs->period_elapsed_pending = 0;
1537 	}
1538 	spin_unlock_irqrestore(&subs->lock, flags);
1539 	if (period_elapsed)
1540 		snd_pcm_period_elapsed(subs->pcm_substream);
1541 }
1542 
1543 /* PCM ack callback for the playback stream;
1544  * this plays a role only when the stream is running in low-latency mode.
1545  */
1546 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1547 {
1548 	struct snd_usb_substream *subs = substream->runtime->private_data;
1549 	struct snd_usb_endpoint *ep;
1550 
1551 	if (!subs->lowlatency_playback || !subs->running)
1552 		return 0;
1553 	ep = subs->data_endpoint;
1554 	if (!ep)
1555 		return 0;
1556 	/* When no more in-flight URBs available, try to process the pending
1557 	 * outputs here
1558 	 */
1559 	if (!ep->active_mask)
1560 		snd_usb_queue_pending_output_urbs(ep, true);
1561 	return 0;
1562 }
1563 
1564 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1565 					      int cmd)
1566 {
1567 	struct snd_usb_substream *subs = substream->runtime->private_data;
1568 	int err;
1569 
1570 	switch (cmd) {
1571 	case SNDRV_PCM_TRIGGER_START:
1572 		subs->trigger_tstamp_pending_update = true;
1573 		fallthrough;
1574 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1575 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1576 					      prepare_playback_urb,
1577 					      retire_playback_urb,
1578 					      subs);
1579 		if (subs->lowlatency_playback &&
1580 		    cmd == SNDRV_PCM_TRIGGER_START) {
1581 			if (in_free_wheeling_mode(substream->runtime))
1582 				subs->lowlatency_playback = false;
1583 			err = start_endpoints(subs);
1584 			if (err < 0) {
1585 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1586 							      NULL, NULL, NULL);
1587 				return err;
1588 			}
1589 		}
1590 		subs->running = 1;
1591 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1592 			subs->cur_audiofmt->iface,
1593 			subs->cur_audiofmt->altsetting);
1594 		return 0;
1595 	case SNDRV_PCM_TRIGGER_SUSPEND:
1596 	case SNDRV_PCM_TRIGGER_STOP:
1597 		stop_endpoints(subs, substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING);
1598 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1599 					      NULL, NULL, NULL);
1600 		subs->running = 0;
1601 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1602 			subs->cur_audiofmt->iface,
1603 			subs->cur_audiofmt->altsetting);
1604 		return 0;
1605 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1606 		/* keep retire_data_urb for delay calculation */
1607 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1608 					      NULL,
1609 					      retire_playback_urb,
1610 					      subs);
1611 		subs->running = 0;
1612 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1613 			subs->cur_audiofmt->iface,
1614 			subs->cur_audiofmt->altsetting);
1615 		return 0;
1616 	}
1617 
1618 	return -EINVAL;
1619 }
1620 
1621 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1622 					     int cmd)
1623 {
1624 	int err;
1625 	struct snd_usb_substream *subs = substream->runtime->private_data;
1626 
1627 	switch (cmd) {
1628 	case SNDRV_PCM_TRIGGER_START:
1629 		err = start_endpoints(subs);
1630 		if (err < 0)
1631 			return err;
1632 		fallthrough;
1633 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1634 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1635 					      NULL, retire_capture_urb,
1636 					      subs);
1637 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1638 		subs->running = 1;
1639 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1640 			subs->cur_audiofmt->iface,
1641 			subs->cur_audiofmt->altsetting);
1642 		return 0;
1643 	case SNDRV_PCM_TRIGGER_SUSPEND:
1644 	case SNDRV_PCM_TRIGGER_STOP:
1645 		stop_endpoints(subs, false);
1646 		fallthrough;
1647 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1648 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1649 					      NULL, NULL, NULL);
1650 		subs->running = 0;
1651 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1652 			subs->cur_audiofmt->iface,
1653 			subs->cur_audiofmt->altsetting);
1654 		return 0;
1655 	}
1656 
1657 	return -EINVAL;
1658 }
1659 
1660 static const struct snd_pcm_ops snd_usb_playback_ops = {
1661 	.open =		snd_usb_pcm_open,
1662 	.close =	snd_usb_pcm_close,
1663 	.hw_params =	snd_usb_hw_params,
1664 	.hw_free =	snd_usb_hw_free,
1665 	.prepare =	snd_usb_pcm_prepare,
1666 	.trigger =	snd_usb_substream_playback_trigger,
1667 	.sync_stop =	snd_usb_pcm_sync_stop,
1668 	.pointer =	snd_usb_pcm_pointer,
1669 	.ack =		snd_usb_pcm_playback_ack,
1670 };
1671 
1672 static const struct snd_pcm_ops snd_usb_capture_ops = {
1673 	.open =		snd_usb_pcm_open,
1674 	.close =	snd_usb_pcm_close,
1675 	.hw_params =	snd_usb_hw_params,
1676 	.hw_free =	snd_usb_hw_free,
1677 	.prepare =	snd_usb_pcm_prepare,
1678 	.trigger =	snd_usb_substream_capture_trigger,
1679 	.sync_stop =	snd_usb_pcm_sync_stop,
1680 	.pointer =	snd_usb_pcm_pointer,
1681 };
1682 
1683 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1684 {
1685 	const struct snd_pcm_ops *ops;
1686 
1687 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1688 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1689 	snd_pcm_set_ops(pcm, stream, ops);
1690 }
1691 
1692 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1693 {
1694 	struct snd_pcm *pcm = subs->stream->pcm;
1695 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1696 	struct device *dev = subs->dev->bus->sysdev;
1697 
1698 	if (snd_usb_use_vmalloc)
1699 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1700 					   NULL, 0, 0);
1701 	else
1702 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1703 					   dev, 64*1024, 512*1024);
1704 }
1705