xref: /openbmc/linux/sound/usb/pcm.c (revision 465191d6)
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 	alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);
295 	if (!alts)
296 		return 0;
297 	altsd = get_iface_desc(alts);
298 
299 	err = snd_usb_parse_implicit_fb_quirk(chip, fmt, alts);
300 	if (err > 0)
301 		return 0; /* matched */
302 
303 	/*
304 	 * Generic sync EP handling
305 	 */
306 
307 	if (altsd->bNumEndpoints < 2)
308 		return 0;
309 
310 	is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);
311 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
312 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
313 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
314 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
315 		return 0;
316 
317 	sync_attr = get_endpoint(alts, 1)->bmAttributes;
318 
319 	/*
320 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
321 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
322 	 * error fall back to SYNC mode and don't create sync endpoint
323 	 */
324 
325 	/* check sync-pipe endpoint */
326 	/* ... and check descriptor size before accessing bSynchAddress
327 	   because there is a version of the SB Audigy 2 NX firmware lacking
328 	   the audio fields in the endpoint descriptors */
329 	if ((sync_attr & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
330 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
331 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
332 		dev_err(&dev->dev,
333 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
334 			   fmt->iface, fmt->altsetting,
335 			   get_endpoint(alts, 1)->bmAttributes,
336 			   get_endpoint(alts, 1)->bLength,
337 			   get_endpoint(alts, 1)->bSynchAddress);
338 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
339 			return 0;
340 		return -EINVAL;
341 	}
342 	ep = get_endpoint(alts, 1)->bEndpointAddress;
343 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
344 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
345 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
346 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
347 		dev_err(&dev->dev,
348 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
349 			   fmt->iface, fmt->altsetting,
350 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
351 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
352 			return 0;
353 		return -EINVAL;
354 	}
355 
356 	fmt->sync_ep = ep;
357 	fmt->sync_iface = altsd->bInterfaceNumber;
358 	fmt->sync_altsetting = altsd->bAlternateSetting;
359 	fmt->sync_ep_idx = 1;
360 	if ((sync_attr & USB_ENDPOINT_USAGE_MASK) == USB_ENDPOINT_USAGE_IMPLICIT_FB)
361 		fmt->implicit_fb = 1;
362 
363 	dev_dbg(&dev->dev, "%d:%d: found sync_ep=0x%x, iface=%d, alt=%d, implicit_fb=%d\n",
364 		fmt->iface, fmt->altsetting, fmt->sync_ep, fmt->sync_iface,
365 		fmt->sync_altsetting, fmt->implicit_fb);
366 
367 	return 0;
368 }
369 
370 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
371 {
372 	int ret;
373 
374 	if (!subs->str_pd)
375 		return 0;
376 
377 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
378 	if (ret < 0) {
379 		dev_err(&subs->dev->dev,
380 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
381 			subs->str_pd->pd_id, state, ret);
382 		return ret;
383 	}
384 
385 	return 0;
386 }
387 
388 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
389 {
390 	int ret;
391 
392 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
393 	if (ret < 0)
394 		return ret;
395 
396 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
397 	if (ret < 0)
398 		return ret;
399 
400 	return 0;
401 }
402 
403 int snd_usb_pcm_resume(struct snd_usb_stream *as)
404 {
405 	int ret;
406 
407 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
408 	if (ret < 0)
409 		return ret;
410 
411 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
412 	if (ret < 0)
413 		return ret;
414 
415 	return 0;
416 }
417 
418 static void close_endpoints(struct snd_usb_audio *chip,
419 			    struct snd_usb_substream *subs)
420 {
421 	if (subs->data_endpoint) {
422 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint, NULL);
423 		snd_usb_endpoint_close(chip, subs->data_endpoint);
424 		subs->data_endpoint = NULL;
425 	}
426 
427 	if (subs->sync_endpoint) {
428 		snd_usb_endpoint_close(chip, subs->sync_endpoint);
429 		subs->sync_endpoint = NULL;
430 	}
431 }
432 
433 static int configure_endpoints(struct snd_usb_audio *chip,
434 			       struct snd_usb_substream *subs)
435 {
436 	int err;
437 
438 	if (subs->data_endpoint->need_setup) {
439 		/* stop any running stream beforehand */
440 		if (stop_endpoints(subs, false))
441 			sync_pending_stops(subs);
442 		if (subs->sync_endpoint) {
443 			err = snd_usb_endpoint_configure(chip, subs->sync_endpoint);
444 			if (err < 0)
445 				return err;
446 		}
447 		err = snd_usb_endpoint_configure(chip, subs->data_endpoint);
448 		if (err < 0)
449 			return err;
450 		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
451 	} else {
452 		if (subs->sync_endpoint) {
453 			err = snd_usb_endpoint_configure(chip, subs->sync_endpoint);
454 			if (err < 0)
455 				return err;
456 		}
457 	}
458 
459 	return 0;
460 }
461 
462 /*
463  * hw_params callback
464  *
465  * allocate a buffer and set the given audio format.
466  *
467  * so far we use a physically linear buffer although packetize transfer
468  * doesn't need a continuous area.
469  * if sg buffer is supported on the later version of alsa, we'll follow
470  * that.
471  */
472 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
473 			     struct snd_pcm_hw_params *hw_params)
474 {
475 	struct snd_usb_substream *subs = substream->runtime->private_data;
476 	struct snd_usb_audio *chip = subs->stream->chip;
477 	const struct audioformat *fmt;
478 	const struct audioformat *sync_fmt;
479 	int ret;
480 
481 	ret = snd_media_start_pipeline(subs);
482 	if (ret)
483 		return ret;
484 
485 	fmt = find_substream_format(subs, hw_params);
486 	if (!fmt) {
487 		usb_audio_dbg(chip,
488 			      "cannot find format: format=%s, rate=%d, channels=%d\n",
489 			      snd_pcm_format_name(params_format(hw_params)),
490 			      params_rate(hw_params), params_channels(hw_params));
491 		ret = -EINVAL;
492 		goto stop_pipeline;
493 	}
494 
495 	if (fmt->implicit_fb) {
496 		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
497 								hw_params,
498 								!substream->stream);
499 		if (!sync_fmt) {
500 			usb_audio_dbg(chip,
501 				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
502 				      fmt->sync_ep, fmt->sync_iface,
503 				      fmt->sync_altsetting,
504 				      snd_pcm_format_name(params_format(hw_params)),
505 				      params_rate(hw_params), params_channels(hw_params));
506 			ret = -EINVAL;
507 			goto stop_pipeline;
508 		}
509 	} else {
510 		sync_fmt = fmt;
511 	}
512 
513 	ret = snd_usb_lock_shutdown(chip);
514 	if (ret < 0)
515 		goto stop_pipeline;
516 
517 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
518 	if (ret < 0)
519 		goto unlock;
520 
521 	if (subs->data_endpoint) {
522 		if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
523 						fmt, hw_params))
524 			goto unlock;
525 		close_endpoints(chip, subs);
526 	}
527 
528 	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false);
529 	if (!subs->data_endpoint) {
530 		ret = -EINVAL;
531 		goto unlock;
532 	}
533 
534 	if (fmt->sync_ep) {
535 		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
536 							    hw_params,
537 							    fmt == sync_fmt);
538 		if (!subs->sync_endpoint) {
539 			ret = -EINVAL;
540 			goto unlock;
541 		}
542 
543 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
544 					  subs->sync_endpoint);
545 	}
546 
547 	mutex_lock(&chip->mutex);
548 	subs->cur_audiofmt = fmt;
549 	mutex_unlock(&chip->mutex);
550 
551 	ret = configure_endpoints(chip, subs);
552 
553  unlock:
554 	if (ret < 0)
555 		close_endpoints(chip, subs);
556 
557 	snd_usb_unlock_shutdown(chip);
558  stop_pipeline:
559 	if (ret < 0)
560 		snd_media_stop_pipeline(subs);
561 
562 	return ret;
563 }
564 
565 /*
566  * hw_free callback
567  *
568  * reset the audio format and release the buffer
569  */
570 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
571 {
572 	struct snd_usb_substream *subs = substream->runtime->private_data;
573 	struct snd_usb_audio *chip = subs->stream->chip;
574 
575 	snd_media_stop_pipeline(subs);
576 	mutex_lock(&chip->mutex);
577 	subs->cur_audiofmt = NULL;
578 	mutex_unlock(&chip->mutex);
579 	if (!snd_usb_lock_shutdown(chip)) {
580 		if (stop_endpoints(subs, false))
581 			sync_pending_stops(subs);
582 		close_endpoints(chip, subs);
583 		snd_usb_unlock_shutdown(chip);
584 	}
585 
586 	return 0;
587 }
588 
589 /* free-wheeling mode? (e.g. dmix) */
590 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
591 {
592 	return runtime->stop_threshold > runtime->buffer_size;
593 }
594 
595 /* check whether early start is needed for playback stream */
596 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
597 					 struct snd_usb_substream *subs)
598 {
599 	struct snd_usb_audio *chip = subs->stream->chip;
600 
601 	if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
602 		return false;
603 	/* disabled via module option? */
604 	if (!chip->lowlatency)
605 		return false;
606 	if (in_free_wheeling_mode(runtime))
607 		return false;
608 	/* implicit feedback mode has own operation mode */
609 	if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
610 		return false;
611 	return true;
612 }
613 
614 /*
615  * prepare callback
616  *
617  * only a few subtle things...
618  */
619 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
620 {
621 	struct snd_pcm_runtime *runtime = substream->runtime;
622 	struct snd_usb_substream *subs = runtime->private_data;
623 	struct snd_usb_audio *chip = subs->stream->chip;
624 	int ret;
625 
626 	ret = snd_usb_lock_shutdown(chip);
627 	if (ret < 0)
628 		return ret;
629 	if (snd_BUG_ON(!subs->data_endpoint)) {
630 		ret = -EIO;
631 		goto unlock;
632 	}
633 
634 	ret = configure_endpoints(chip, subs);
635 	if (ret < 0)
636 		goto unlock;
637 
638 	/* reset the pointer */
639 	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
640 	subs->inflight_bytes = 0;
641 	subs->hwptr_done = 0;
642 	subs->transfer_done = 0;
643 	subs->last_frame_number = 0;
644 	subs->period_elapsed_pending = 0;
645 	runtime->delay = 0;
646 
647 	subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
648 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
649 	    !subs->lowlatency_playback)
650 		ret = start_endpoints(subs);
651 
652  unlock:
653 	snd_usb_unlock_shutdown(chip);
654 	return ret;
655 }
656 
657 /*
658  * h/w constraints
659  */
660 
661 #ifdef HW_CONST_DEBUG
662 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
663 #else
664 #define hwc_debug(fmt, args...) do { } while(0)
665 #endif
666 
667 static const struct snd_pcm_hardware snd_usb_hardware =
668 {
669 	.info =			SNDRV_PCM_INFO_MMAP |
670 				SNDRV_PCM_INFO_MMAP_VALID |
671 				SNDRV_PCM_INFO_BATCH |
672 				SNDRV_PCM_INFO_INTERLEAVED |
673 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
674 				SNDRV_PCM_INFO_PAUSE,
675 	.channels_min =		1,
676 	.channels_max =		256,
677 	.buffer_bytes_max =	INT_MAX, /* limited by BUFFER_TIME later */
678 	.period_bytes_min =	64,
679 	.period_bytes_max =	INT_MAX, /* limited by PERIOD_TIME later */
680 	.periods_min =		2,
681 	.periods_max =		1024,
682 };
683 
684 static int hw_check_valid_format(struct snd_usb_substream *subs,
685 				 struct snd_pcm_hw_params *params,
686 				 const struct audioformat *fp)
687 {
688 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
689 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
690 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
691 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
692 	struct snd_mask check_fmts;
693 	unsigned int ptime;
694 
695 	/* check the format */
696 	snd_mask_none(&check_fmts);
697 	check_fmts.bits[0] = (u32)fp->formats;
698 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
699 	snd_mask_intersect(&check_fmts, fmts);
700 	if (snd_mask_empty(&check_fmts)) {
701 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
702 		return 0;
703 	}
704 	/* check the channels */
705 	if (fp->channels < ct->min || fp->channels > ct->max) {
706 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
707 		return 0;
708 	}
709 	/* check the rate is within the range */
710 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
711 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
712 		return 0;
713 	}
714 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
715 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
716 		return 0;
717 	}
718 	/* check whether the period time is >= the data packet interval */
719 	if (subs->speed != USB_SPEED_FULL) {
720 		ptime = 125 * (1 << fp->datainterval);
721 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
722 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
723 			return 0;
724 		}
725 	}
726 	return 1;
727 }
728 
729 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
730 				  unsigned int rmax)
731 {
732 	int changed;
733 
734 	if (rmin > rmax) {
735 		hwc_debug("  --> get empty\n");
736 		it->empty = 1;
737 		return -EINVAL;
738 	}
739 
740 	changed = 0;
741 	if (it->min < rmin) {
742 		it->min = rmin;
743 		it->openmin = 0;
744 		changed = 1;
745 	}
746 	if (it->max > rmax) {
747 		it->max = rmax;
748 		it->openmax = 0;
749 		changed = 1;
750 	}
751 	if (snd_interval_checkempty(it)) {
752 		it->empty = 1;
753 		return -EINVAL;
754 	}
755 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
756 	return changed;
757 }
758 
759 static int hw_rule_rate(struct snd_pcm_hw_params *params,
760 			struct snd_pcm_hw_rule *rule)
761 {
762 	struct snd_usb_substream *subs = rule->private;
763 	struct snd_usb_audio *chip = subs->stream->chip;
764 	const struct audioformat *fp;
765 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
766 	unsigned int rmin, rmax, r;
767 	int i;
768 
769 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
770 	rmin = UINT_MAX;
771 	rmax = 0;
772 	list_for_each_entry(fp, &subs->fmt_list, list) {
773 		if (!hw_check_valid_format(subs, params, fp))
774 			continue;
775 		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
776 		if (r > 0) {
777 			if (!snd_interval_test(it, r))
778 				continue;
779 			rmin = min(rmin, r);
780 			rmax = max(rmax, r);
781 			continue;
782 		}
783 		if (fp->rate_table && fp->nr_rates) {
784 			for (i = 0; i < fp->nr_rates; i++) {
785 				r = fp->rate_table[i];
786 				if (!snd_interval_test(it, r))
787 					continue;
788 				rmin = min(rmin, r);
789 				rmax = max(rmax, r);
790 			}
791 		} else {
792 			rmin = min(rmin, fp->rate_min);
793 			rmax = max(rmax, fp->rate_max);
794 		}
795 	}
796 
797 	return apply_hw_params_minmax(it, rmin, rmax);
798 }
799 
800 
801 static int hw_rule_channels(struct snd_pcm_hw_params *params,
802 			    struct snd_pcm_hw_rule *rule)
803 {
804 	struct snd_usb_substream *subs = rule->private;
805 	const struct audioformat *fp;
806 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
807 	unsigned int rmin, rmax;
808 
809 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
810 	rmin = UINT_MAX;
811 	rmax = 0;
812 	list_for_each_entry(fp, &subs->fmt_list, list) {
813 		if (!hw_check_valid_format(subs, params, fp))
814 			continue;
815 		rmin = min(rmin, fp->channels);
816 		rmax = max(rmax, fp->channels);
817 	}
818 
819 	return apply_hw_params_minmax(it, rmin, rmax);
820 }
821 
822 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
823 {
824 	u32 oldbits[2];
825 	int changed;
826 
827 	oldbits[0] = fmt->bits[0];
828 	oldbits[1] = fmt->bits[1];
829 	fmt->bits[0] &= (u32)fbits;
830 	fmt->bits[1] &= (u32)(fbits >> 32);
831 	if (!fmt->bits[0] && !fmt->bits[1]) {
832 		hwc_debug("  --> get empty\n");
833 		return -EINVAL;
834 	}
835 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
836 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
837 	return changed;
838 }
839 
840 static int hw_rule_format(struct snd_pcm_hw_params *params,
841 			  struct snd_pcm_hw_rule *rule)
842 {
843 	struct snd_usb_substream *subs = rule->private;
844 	const struct audioformat *fp;
845 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
846 	u64 fbits;
847 
848 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
849 	fbits = 0;
850 	list_for_each_entry(fp, &subs->fmt_list, list) {
851 		if (!hw_check_valid_format(subs, params, fp))
852 			continue;
853 		fbits |= fp->formats;
854 	}
855 	return apply_hw_params_format_bits(fmt, fbits);
856 }
857 
858 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
859 			       struct snd_pcm_hw_rule *rule)
860 {
861 	struct snd_usb_substream *subs = rule->private;
862 	const struct audioformat *fp;
863 	struct snd_interval *it;
864 	unsigned char min_datainterval;
865 	unsigned int pmin;
866 
867 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
868 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
869 	min_datainterval = 0xff;
870 	list_for_each_entry(fp, &subs->fmt_list, list) {
871 		if (!hw_check_valid_format(subs, params, fp))
872 			continue;
873 		min_datainterval = min(min_datainterval, fp->datainterval);
874 	}
875 	if (min_datainterval == 0xff) {
876 		hwc_debug("  --> get empty\n");
877 		it->empty = 1;
878 		return -EINVAL;
879 	}
880 	pmin = 125 * (1 << min_datainterval);
881 
882 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
883 }
884 
885 /* get the EP or the sync EP for implicit fb when it's already set up */
886 static const struct snd_usb_endpoint *
887 get_sync_ep_from_substream(struct snd_usb_substream *subs)
888 {
889 	struct snd_usb_audio *chip = subs->stream->chip;
890 	const struct audioformat *fp;
891 	const struct snd_usb_endpoint *ep;
892 
893 	list_for_each_entry(fp, &subs->fmt_list, list) {
894 		ep = snd_usb_get_endpoint(chip, fp->endpoint);
895 		if (ep && ep->cur_audiofmt) {
896 			/* if EP is already opened solely for this substream,
897 			 * we still allow us to change the parameter; otherwise
898 			 * this substream has to follow the existing parameter
899 			 */
900 			if (ep->cur_audiofmt != subs->cur_audiofmt || ep->opened > 1)
901 				return ep;
902 		}
903 		if (!fp->implicit_fb)
904 			continue;
905 		/* for the implicit fb, check the sync ep as well */
906 		ep = snd_usb_get_endpoint(chip, fp->sync_ep);
907 		if (ep && ep->cur_audiofmt)
908 			return ep;
909 	}
910 	return NULL;
911 }
912 
913 /* additional hw constraints for implicit feedback mode */
914 static int hw_rule_format_implicit_fb(struct snd_pcm_hw_params *params,
915 				      struct snd_pcm_hw_rule *rule)
916 {
917 	struct snd_usb_substream *subs = rule->private;
918 	const struct snd_usb_endpoint *ep;
919 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
920 
921 	ep = get_sync_ep_from_substream(subs);
922 	if (!ep)
923 		return 0;
924 
925 	hwc_debug("applying %s\n", __func__);
926 	return apply_hw_params_format_bits(fmt, pcm_format_to_bits(ep->cur_format));
927 }
928 
929 static int hw_rule_rate_implicit_fb(struct snd_pcm_hw_params *params,
930 				    struct snd_pcm_hw_rule *rule)
931 {
932 	struct snd_usb_substream *subs = rule->private;
933 	const struct snd_usb_endpoint *ep;
934 	struct snd_interval *it;
935 
936 	ep = get_sync_ep_from_substream(subs);
937 	if (!ep)
938 		return 0;
939 
940 	hwc_debug("applying %s\n", __func__);
941 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
942 	return apply_hw_params_minmax(it, ep->cur_rate, ep->cur_rate);
943 }
944 
945 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
946 					   struct snd_pcm_hw_rule *rule)
947 {
948 	struct snd_usb_substream *subs = rule->private;
949 	const struct snd_usb_endpoint *ep;
950 	struct snd_interval *it;
951 
952 	ep = get_sync_ep_from_substream(subs);
953 	if (!ep)
954 		return 0;
955 
956 	hwc_debug("applying %s\n", __func__);
957 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
958 	return apply_hw_params_minmax(it, ep->cur_period_frames,
959 				      ep->cur_period_frames);
960 }
961 
962 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
963 				       struct snd_pcm_hw_rule *rule)
964 {
965 	struct snd_usb_substream *subs = rule->private;
966 	const struct snd_usb_endpoint *ep;
967 	struct snd_interval *it;
968 
969 	ep = get_sync_ep_from_substream(subs);
970 	if (!ep)
971 		return 0;
972 
973 	hwc_debug("applying %s\n", __func__);
974 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
975 	return apply_hw_params_minmax(it, ep->cur_buffer_periods,
976 				      ep->cur_buffer_periods);
977 }
978 
979 /*
980  * set up the runtime hardware information.
981  */
982 
983 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
984 {
985 	const struct audioformat *fp;
986 	unsigned int pt, ptmin;
987 	int param_period_time_if_needed = -1;
988 	int err;
989 
990 	runtime->hw.formats = subs->formats;
991 
992 	runtime->hw.rate_min = 0x7fffffff;
993 	runtime->hw.rate_max = 0;
994 	runtime->hw.channels_min = 256;
995 	runtime->hw.channels_max = 0;
996 	runtime->hw.rates = 0;
997 	ptmin = UINT_MAX;
998 	/* check min/max rates and channels */
999 	list_for_each_entry(fp, &subs->fmt_list, list) {
1000 		runtime->hw.rates |= fp->rates;
1001 		if (runtime->hw.rate_min > fp->rate_min)
1002 			runtime->hw.rate_min = fp->rate_min;
1003 		if (runtime->hw.rate_max < fp->rate_max)
1004 			runtime->hw.rate_max = fp->rate_max;
1005 		if (runtime->hw.channels_min > fp->channels)
1006 			runtime->hw.channels_min = fp->channels;
1007 		if (runtime->hw.channels_max < fp->channels)
1008 			runtime->hw.channels_max = fp->channels;
1009 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1010 			/* FIXME: there might be more than one audio formats... */
1011 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1012 				fp->frame_size;
1013 		}
1014 		pt = 125 * (1 << fp->datainterval);
1015 		ptmin = min(ptmin, pt);
1016 	}
1017 
1018 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1019 	if (subs->speed == USB_SPEED_FULL)
1020 		/* full speed devices have fixed data packet interval */
1021 		ptmin = 1000;
1022 	if (ptmin == 1000)
1023 		/* if period time doesn't go below 1 ms, no rules needed */
1024 		param_period_time_if_needed = -1;
1025 
1026 	err = snd_pcm_hw_constraint_minmax(runtime,
1027 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1028 					   ptmin, UINT_MAX);
1029 	if (err < 0)
1030 		return err;
1031 
1032 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1033 				  hw_rule_rate, subs,
1034 				  SNDRV_PCM_HW_PARAM_RATE,
1035 				  SNDRV_PCM_HW_PARAM_FORMAT,
1036 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1037 				  param_period_time_if_needed,
1038 				  -1);
1039 	if (err < 0)
1040 		return err;
1041 
1042 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1043 				  hw_rule_channels, subs,
1044 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1045 				  SNDRV_PCM_HW_PARAM_FORMAT,
1046 				  SNDRV_PCM_HW_PARAM_RATE,
1047 				  param_period_time_if_needed,
1048 				  -1);
1049 	if (err < 0)
1050 		return err;
1051 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1052 				  hw_rule_format, subs,
1053 				  SNDRV_PCM_HW_PARAM_FORMAT,
1054 				  SNDRV_PCM_HW_PARAM_RATE,
1055 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1056 				  param_period_time_if_needed,
1057 				  -1);
1058 	if (err < 0)
1059 		return err;
1060 	if (param_period_time_if_needed >= 0) {
1061 		err = snd_pcm_hw_rule_add(runtime, 0,
1062 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1063 					  hw_rule_period_time, subs,
1064 					  SNDRV_PCM_HW_PARAM_FORMAT,
1065 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1066 					  SNDRV_PCM_HW_PARAM_RATE,
1067 					  -1);
1068 		if (err < 0)
1069 			return err;
1070 	}
1071 
1072 	/* set max period and buffer sizes for 1 and 2 seconds, respectively */
1073 	err = snd_pcm_hw_constraint_minmax(runtime,
1074 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1075 					   0, 1000000);
1076 	if (err < 0)
1077 		return err;
1078 	err = snd_pcm_hw_constraint_minmax(runtime,
1079 					   SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1080 					   0, 2000000);
1081 	if (err < 0)
1082 		return err;
1083 
1084 	/* additional hw constraints for implicit fb */
1085 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1086 				  hw_rule_format_implicit_fb, subs,
1087 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1088 	if (err < 0)
1089 		return err;
1090 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1091 				  hw_rule_rate_implicit_fb, subs,
1092 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1093 	if (err < 0)
1094 		return err;
1095 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1096 				  hw_rule_period_size_implicit_fb, subs,
1097 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1098 	if (err < 0)
1099 		return err;
1100 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1101 				  hw_rule_periods_implicit_fb, subs,
1102 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1103 	if (err < 0)
1104 		return err;
1105 
1106 	list_for_each_entry(fp, &subs->fmt_list, list) {
1107 		if (fp->implicit_fb) {
1108 			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1109 			break;
1110 		}
1111 	}
1112 
1113 	return 0;
1114 }
1115 
1116 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1117 {
1118 	int direction = substream->stream;
1119 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1120 	struct snd_pcm_runtime *runtime = substream->runtime;
1121 	struct snd_usb_substream *subs = &as->substream[direction];
1122 	int ret;
1123 
1124 	runtime->hw = snd_usb_hardware;
1125 	/* need an explicit sync to catch applptr update in low-latency mode */
1126 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1127 	    as->chip->lowlatency)
1128 		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1129 	runtime->private_data = subs;
1130 	subs->pcm_substream = substream;
1131 	/* runtime PM is also done there */
1132 
1133 	/* initialize DSD/DOP context */
1134 	subs->dsd_dop.byte_idx = 0;
1135 	subs->dsd_dop.channel = 0;
1136 	subs->dsd_dop.marker = 1;
1137 
1138 	ret = setup_hw_info(runtime, subs);
1139 	if (ret < 0)
1140 		return ret;
1141 	ret = snd_usb_autoresume(subs->stream->chip);
1142 	if (ret < 0)
1143 		return ret;
1144 	ret = snd_media_stream_init(subs, as->pcm, direction);
1145 	if (ret < 0)
1146 		snd_usb_autosuspend(subs->stream->chip);
1147 	return ret;
1148 }
1149 
1150 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1151 {
1152 	int direction = substream->stream;
1153 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1154 	struct snd_usb_substream *subs = &as->substream[direction];
1155 	int ret;
1156 
1157 	snd_media_stop_pipeline(subs);
1158 
1159 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1160 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1161 		snd_usb_unlock_shutdown(subs->stream->chip);
1162 		if (ret < 0)
1163 			return ret;
1164 	}
1165 
1166 	subs->pcm_substream = NULL;
1167 	snd_usb_autosuspend(subs->stream->chip);
1168 
1169 	return 0;
1170 }
1171 
1172 /* Since a URB can handle only a single linear buffer, we must use double
1173  * buffering when the data to be transferred overflows the buffer boundary.
1174  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1175  * for all URBs.
1176  */
1177 static void retire_capture_urb(struct snd_usb_substream *subs,
1178 			       struct urb *urb)
1179 {
1180 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1181 	unsigned int stride, frames, bytes, oldptr;
1182 	int i, period_elapsed = 0;
1183 	unsigned long flags;
1184 	unsigned char *cp;
1185 	int current_frame_number;
1186 
1187 	/* read frame number here, update pointer in critical section */
1188 	current_frame_number = usb_get_current_frame_number(subs->dev);
1189 
1190 	stride = runtime->frame_bits >> 3;
1191 
1192 	for (i = 0; i < urb->number_of_packets; i++) {
1193 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1194 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1195 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1196 				i, urb->iso_frame_desc[i].status);
1197 			// continue;
1198 		}
1199 		bytes = urb->iso_frame_desc[i].actual_length;
1200 		if (subs->stream_offset_adj > 0) {
1201 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1202 			cp += adj;
1203 			bytes -= adj;
1204 			subs->stream_offset_adj -= adj;
1205 		}
1206 		frames = bytes / stride;
1207 		if (!subs->txfr_quirk)
1208 			bytes = frames * stride;
1209 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1210 			int oldbytes = bytes;
1211 			bytes = frames * stride;
1212 			dev_warn_ratelimited(&subs->dev->dev,
1213 				 "Corrected urb data len. %d->%d\n",
1214 							oldbytes, bytes);
1215 		}
1216 		/* update the current pointer */
1217 		spin_lock_irqsave(&subs->lock, flags);
1218 		oldptr = subs->hwptr_done;
1219 		subs->hwptr_done += bytes;
1220 		if (subs->hwptr_done >= subs->buffer_bytes)
1221 			subs->hwptr_done -= subs->buffer_bytes;
1222 		frames = (bytes + (oldptr % stride)) / stride;
1223 		subs->transfer_done += frames;
1224 		if (subs->transfer_done >= runtime->period_size) {
1225 			subs->transfer_done -= runtime->period_size;
1226 			period_elapsed = 1;
1227 		}
1228 
1229 		/* realign last_frame_number */
1230 		subs->last_frame_number = current_frame_number;
1231 
1232 		spin_unlock_irqrestore(&subs->lock, flags);
1233 		/* copy a data chunk */
1234 		if (oldptr + bytes > subs->buffer_bytes) {
1235 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1236 
1237 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1238 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1239 		} else {
1240 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1241 		}
1242 	}
1243 
1244 	if (period_elapsed)
1245 		snd_pcm_period_elapsed(subs->pcm_substream);
1246 }
1247 
1248 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1249 				  struct urb *urb, unsigned int bytes)
1250 {
1251 	struct snd_urb_ctx *ctx = urb->context;
1252 
1253 	ctx->queued += bytes;
1254 	subs->inflight_bytes += bytes;
1255 	subs->hwptr_done += bytes;
1256 	if (subs->hwptr_done >= subs->buffer_bytes)
1257 		subs->hwptr_done -= subs->buffer_bytes;
1258 }
1259 
1260 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1261 					     struct urb *urb, unsigned int bytes)
1262 {
1263 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1264 	unsigned int dst_idx = 0;
1265 	unsigned int src_idx = subs->hwptr_done;
1266 	unsigned int wrap = subs->buffer_bytes;
1267 	u8 *dst = urb->transfer_buffer;
1268 	u8 *src = runtime->dma_area;
1269 	u8 marker[] = { 0x05, 0xfa };
1270 	unsigned int queued = 0;
1271 
1272 	/*
1273 	 * The DSP DOP format defines a way to transport DSD samples over
1274 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1275 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1276 	 * 2 additional bytes of actual payload. The whole frame is stored
1277 	 * LSB.
1278 	 *
1279 	 * Hence, for a stereo transport, the buffer layout looks like this,
1280 	 * where L refers to left channel samples and R to right.
1281 	 *
1282 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1283 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1284 	 *   .....
1285 	 *
1286 	 */
1287 
1288 	while (bytes--) {
1289 		if (++subs->dsd_dop.byte_idx == 3) {
1290 			/* frame boundary? */
1291 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1292 			src_idx += 2;
1293 			subs->dsd_dop.byte_idx = 0;
1294 
1295 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1296 				/* alternate the marker */
1297 				subs->dsd_dop.marker++;
1298 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1299 				subs->dsd_dop.channel = 0;
1300 			}
1301 		} else {
1302 			/* stuff the DSD payload */
1303 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1304 
1305 			if (subs->cur_audiofmt->dsd_bitrev)
1306 				dst[dst_idx++] = bitrev8(src[idx]);
1307 			else
1308 				dst[dst_idx++] = src[idx];
1309 			queued++;
1310 		}
1311 	}
1312 
1313 	urb_ctx_queue_advance(subs, urb, queued);
1314 }
1315 
1316 /* copy bit-reversed bytes onto transfer buffer */
1317 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1318 					 struct urb *urb, unsigned int bytes)
1319 {
1320 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1321 	const u8 *src = runtime->dma_area;
1322 	u8 *buf = urb->transfer_buffer;
1323 	int i, ofs = subs->hwptr_done;
1324 
1325 	for (i = 0; i < bytes; i++) {
1326 		*buf++ = bitrev8(src[ofs]);
1327 		if (++ofs >= subs->buffer_bytes)
1328 			ofs = 0;
1329 	}
1330 
1331 	urb_ctx_queue_advance(subs, urb, bytes);
1332 }
1333 
1334 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1335 			int offset, int stride, unsigned int bytes)
1336 {
1337 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1338 
1339 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1340 		/* err, the transferred area goes over buffer boundary. */
1341 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1342 
1343 		memcpy(urb->transfer_buffer + offset,
1344 		       runtime->dma_area + subs->hwptr_done, bytes1);
1345 		memcpy(urb->transfer_buffer + offset + bytes1,
1346 		       runtime->dma_area, bytes - bytes1);
1347 	} else {
1348 		memcpy(urb->transfer_buffer + offset,
1349 		       runtime->dma_area + subs->hwptr_done, bytes);
1350 	}
1351 
1352 	urb_ctx_queue_advance(subs, urb, bytes);
1353 }
1354 
1355 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1356 				      struct urb *urb, int stride,
1357 				      unsigned int bytes)
1358 {
1359 	__le32 packet_length;
1360 	int i;
1361 
1362 	/* Put __le32 length descriptor at start of each packet. */
1363 	for (i = 0; i < urb->number_of_packets; i++) {
1364 		unsigned int length = urb->iso_frame_desc[i].length;
1365 		unsigned int offset = urb->iso_frame_desc[i].offset;
1366 
1367 		packet_length = cpu_to_le32(length);
1368 		offset += i * sizeof(packet_length);
1369 		urb->iso_frame_desc[i].offset = offset;
1370 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1371 		memcpy(urb->transfer_buffer + offset,
1372 		       &packet_length, sizeof(packet_length));
1373 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1374 			    stride, length);
1375 	}
1376 	/* Adjust transfer size accordingly. */
1377 	bytes += urb->number_of_packets * sizeof(packet_length);
1378 	return bytes;
1379 }
1380 
1381 static int prepare_playback_urb(struct snd_usb_substream *subs,
1382 				struct urb *urb,
1383 				bool in_stream_lock)
1384 {
1385 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1386 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1387 	struct snd_urb_ctx *ctx = urb->context;
1388 	unsigned int frames, bytes;
1389 	int counts;
1390 	unsigned int transfer_done, frame_limit, avail = 0;
1391 	int i, stride, period_elapsed = 0;
1392 	unsigned long flags;
1393 	int err = 0;
1394 
1395 	stride = ep->stride;
1396 
1397 	frames = 0;
1398 	ctx->queued = 0;
1399 	urb->number_of_packets = 0;
1400 
1401 	spin_lock_irqsave(&subs->lock, flags);
1402 	frame_limit = subs->frame_limit + ep->max_urb_frames;
1403 	transfer_done = subs->transfer_done;
1404 
1405 	if (subs->lowlatency_playback &&
1406 	    runtime->status->state != SNDRV_PCM_STATE_DRAINING) {
1407 		unsigned int hwptr = subs->hwptr_done / stride;
1408 
1409 		/* calculate the byte offset-in-buffer of the appl_ptr */
1410 		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1411 			% runtime->buffer_size;
1412 		if (avail <= hwptr)
1413 			avail += runtime->buffer_size;
1414 		avail -= hwptr;
1415 	}
1416 
1417 	for (i = 0; i < ctx->packets; i++) {
1418 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1419 		if (counts < 0)
1420 			break;
1421 		/* set up descriptor */
1422 		urb->iso_frame_desc[i].offset = frames * stride;
1423 		urb->iso_frame_desc[i].length = counts * stride;
1424 		frames += counts;
1425 		avail -= counts;
1426 		urb->number_of_packets++;
1427 		transfer_done += counts;
1428 		if (transfer_done >= runtime->period_size) {
1429 			transfer_done -= runtime->period_size;
1430 			frame_limit = 0;
1431 			period_elapsed = 1;
1432 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1433 				if (transfer_done > 0) {
1434 					/* FIXME: fill-max mode is not
1435 					 * supported yet */
1436 					frames -= transfer_done;
1437 					counts -= transfer_done;
1438 					urb->iso_frame_desc[i].length =
1439 						counts * stride;
1440 					transfer_done = 0;
1441 				}
1442 				i++;
1443 				if (i < ctx->packets) {
1444 					/* add a transfer delimiter */
1445 					urb->iso_frame_desc[i].offset =
1446 						frames * stride;
1447 					urb->iso_frame_desc[i].length = 0;
1448 					urb->number_of_packets++;
1449 				}
1450 				break;
1451 			}
1452 		}
1453 		/* finish at the period boundary or after enough frames */
1454 		if ((period_elapsed || transfer_done >= frame_limit) &&
1455 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1456 			break;
1457 	}
1458 
1459 	if (!frames) {
1460 		err = -EAGAIN;
1461 		goto unlock;
1462 	}
1463 
1464 	bytes = frames * stride;
1465 	subs->transfer_done = transfer_done;
1466 	subs->frame_limit = frame_limit;
1467 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1468 		     subs->cur_audiofmt->dsd_dop)) {
1469 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1470 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1471 			   subs->cur_audiofmt->dsd_bitrev)) {
1472 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1473 	} else {
1474 		/* usual PCM */
1475 		if (!subs->tx_length_quirk)
1476 			copy_to_urb(subs, urb, 0, stride, bytes);
1477 		else
1478 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1479 			/* bytes is now amount of outgoing data */
1480 	}
1481 
1482 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1483 
1484 	if (subs->trigger_tstamp_pending_update) {
1485 		/* this is the first actual URB submitted,
1486 		 * update trigger timestamp to reflect actual start time
1487 		 */
1488 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1489 		subs->trigger_tstamp_pending_update = false;
1490 	}
1491 
1492 	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1493 		subs->period_elapsed_pending = 1;
1494 		period_elapsed = 0;
1495 	}
1496 
1497  unlock:
1498 	spin_unlock_irqrestore(&subs->lock, flags);
1499 	if (err < 0)
1500 		return err;
1501 	urb->transfer_buffer_length = bytes;
1502 	if (period_elapsed) {
1503 		if (in_stream_lock)
1504 			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1505 		else
1506 			snd_pcm_period_elapsed(subs->pcm_substream);
1507 	}
1508 	return 0;
1509 }
1510 
1511 /*
1512  * process after playback data complete
1513  * - decrease the delay count again
1514  */
1515 static void retire_playback_urb(struct snd_usb_substream *subs,
1516 			       struct urb *urb)
1517 {
1518 	unsigned long flags;
1519 	struct snd_urb_ctx *ctx = urb->context;
1520 	bool period_elapsed = false;
1521 
1522 	spin_lock_irqsave(&subs->lock, flags);
1523 	if (ctx->queued) {
1524 		if (subs->inflight_bytes >= ctx->queued)
1525 			subs->inflight_bytes -= ctx->queued;
1526 		else
1527 			subs->inflight_bytes = 0;
1528 	}
1529 
1530 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1531 	if (subs->running) {
1532 		period_elapsed = subs->period_elapsed_pending;
1533 		subs->period_elapsed_pending = 0;
1534 	}
1535 	spin_unlock_irqrestore(&subs->lock, flags);
1536 	if (period_elapsed)
1537 		snd_pcm_period_elapsed(subs->pcm_substream);
1538 }
1539 
1540 /* PCM ack callback for the playback stream;
1541  * this plays a role only when the stream is running in low-latency mode.
1542  */
1543 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1544 {
1545 	struct snd_usb_substream *subs = substream->runtime->private_data;
1546 	struct snd_usb_endpoint *ep;
1547 
1548 	if (!subs->lowlatency_playback || !subs->running)
1549 		return 0;
1550 	ep = subs->data_endpoint;
1551 	if (!ep)
1552 		return 0;
1553 	/* When no more in-flight URBs available, try to process the pending
1554 	 * outputs here
1555 	 */
1556 	if (!ep->active_mask)
1557 		snd_usb_queue_pending_output_urbs(ep, true);
1558 	return 0;
1559 }
1560 
1561 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1562 					      int cmd)
1563 {
1564 	struct snd_usb_substream *subs = substream->runtime->private_data;
1565 	int err;
1566 
1567 	switch (cmd) {
1568 	case SNDRV_PCM_TRIGGER_START:
1569 		subs->trigger_tstamp_pending_update = true;
1570 		fallthrough;
1571 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1572 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1573 					      prepare_playback_urb,
1574 					      retire_playback_urb,
1575 					      subs);
1576 		if (subs->lowlatency_playback &&
1577 		    cmd == SNDRV_PCM_TRIGGER_START) {
1578 			if (in_free_wheeling_mode(substream->runtime))
1579 				subs->lowlatency_playback = false;
1580 			err = start_endpoints(subs);
1581 			if (err < 0) {
1582 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1583 							      NULL, NULL, NULL);
1584 				return err;
1585 			}
1586 		}
1587 		subs->running = 1;
1588 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1589 			subs->cur_audiofmt->iface,
1590 			subs->cur_audiofmt->altsetting);
1591 		return 0;
1592 	case SNDRV_PCM_TRIGGER_SUSPEND:
1593 	case SNDRV_PCM_TRIGGER_STOP:
1594 		stop_endpoints(subs, substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING);
1595 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1596 					      NULL, NULL, NULL);
1597 		subs->running = 0;
1598 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1599 			subs->cur_audiofmt->iface,
1600 			subs->cur_audiofmt->altsetting);
1601 		return 0;
1602 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1603 		/* keep retire_data_urb for delay calculation */
1604 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1605 					      NULL,
1606 					      retire_playback_urb,
1607 					      subs);
1608 		subs->running = 0;
1609 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1610 			subs->cur_audiofmt->iface,
1611 			subs->cur_audiofmt->altsetting);
1612 		return 0;
1613 	}
1614 
1615 	return -EINVAL;
1616 }
1617 
1618 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1619 					     int cmd)
1620 {
1621 	int err;
1622 	struct snd_usb_substream *subs = substream->runtime->private_data;
1623 
1624 	switch (cmd) {
1625 	case SNDRV_PCM_TRIGGER_START:
1626 		err = start_endpoints(subs);
1627 		if (err < 0)
1628 			return err;
1629 		fallthrough;
1630 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1631 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1632 					      NULL, retire_capture_urb,
1633 					      subs);
1634 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1635 		subs->running = 1;
1636 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1637 			subs->cur_audiofmt->iface,
1638 			subs->cur_audiofmt->altsetting);
1639 		return 0;
1640 	case SNDRV_PCM_TRIGGER_SUSPEND:
1641 	case SNDRV_PCM_TRIGGER_STOP:
1642 		stop_endpoints(subs, false);
1643 		fallthrough;
1644 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1645 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1646 					      NULL, NULL, NULL);
1647 		subs->running = 0;
1648 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1649 			subs->cur_audiofmt->iface,
1650 			subs->cur_audiofmt->altsetting);
1651 		return 0;
1652 	}
1653 
1654 	return -EINVAL;
1655 }
1656 
1657 static const struct snd_pcm_ops snd_usb_playback_ops = {
1658 	.open =		snd_usb_pcm_open,
1659 	.close =	snd_usb_pcm_close,
1660 	.hw_params =	snd_usb_hw_params,
1661 	.hw_free =	snd_usb_hw_free,
1662 	.prepare =	snd_usb_pcm_prepare,
1663 	.trigger =	snd_usb_substream_playback_trigger,
1664 	.sync_stop =	snd_usb_pcm_sync_stop,
1665 	.pointer =	snd_usb_pcm_pointer,
1666 	.ack =		snd_usb_pcm_playback_ack,
1667 };
1668 
1669 static const struct snd_pcm_ops snd_usb_capture_ops = {
1670 	.open =		snd_usb_pcm_open,
1671 	.close =	snd_usb_pcm_close,
1672 	.hw_params =	snd_usb_hw_params,
1673 	.hw_free =	snd_usb_hw_free,
1674 	.prepare =	snd_usb_pcm_prepare,
1675 	.trigger =	snd_usb_substream_capture_trigger,
1676 	.sync_stop =	snd_usb_pcm_sync_stop,
1677 	.pointer =	snd_usb_pcm_pointer,
1678 };
1679 
1680 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1681 {
1682 	const struct snd_pcm_ops *ops;
1683 
1684 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1685 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1686 	snd_pcm_set_ops(pcm, stream, ops);
1687 }
1688 
1689 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1690 {
1691 	struct snd_pcm *pcm = subs->stream->pcm;
1692 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1693 	struct device *dev = subs->dev->bus->sysdev;
1694 
1695 	if (snd_usb_use_vmalloc)
1696 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1697 					   NULL, 0, 0);
1698 	else
1699 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1700 					   dev, 64*1024, 512*1024);
1701 }
1702