xref: /openbmc/linux/sound/usb/pcm.c (revision 5e154dfb)
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 		err = snd_usb_endpoint_configure(chip, subs->data_endpoint);
443 		if (err < 0)
444 			return err;
445 		snd_usb_set_format_quirk(subs, subs->cur_audiofmt);
446 	}
447 
448 	if (subs->sync_endpoint) {
449 		err = snd_usb_endpoint_configure(chip, subs->sync_endpoint);
450 		if (err < 0)
451 			return err;
452 	}
453 
454 	return 0;
455 }
456 
457 /*
458  * hw_params callback
459  *
460  * allocate a buffer and set the given audio format.
461  *
462  * so far we use a physically linear buffer although packetize transfer
463  * doesn't need a continuous area.
464  * if sg buffer is supported on the later version of alsa, we'll follow
465  * that.
466  */
467 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
468 			     struct snd_pcm_hw_params *hw_params)
469 {
470 	struct snd_usb_substream *subs = substream->runtime->private_data;
471 	struct snd_usb_audio *chip = subs->stream->chip;
472 	const struct audioformat *fmt;
473 	const struct audioformat *sync_fmt;
474 	int ret;
475 
476 	ret = snd_media_start_pipeline(subs);
477 	if (ret)
478 		return ret;
479 
480 	fmt = find_substream_format(subs, hw_params);
481 	if (!fmt) {
482 		usb_audio_dbg(chip,
483 			      "cannot find format: format=%s, rate=%d, channels=%d\n",
484 			      snd_pcm_format_name(params_format(hw_params)),
485 			      params_rate(hw_params), params_channels(hw_params));
486 		ret = -EINVAL;
487 		goto stop_pipeline;
488 	}
489 
490 	if (fmt->implicit_fb) {
491 		sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt,
492 								hw_params,
493 								!substream->stream);
494 		if (!sync_fmt) {
495 			usb_audio_dbg(chip,
496 				      "cannot find sync format: ep=0x%x, iface=%d:%d, format=%s, rate=%d, channels=%d\n",
497 				      fmt->sync_ep, fmt->sync_iface,
498 				      fmt->sync_altsetting,
499 				      snd_pcm_format_name(params_format(hw_params)),
500 				      params_rate(hw_params), params_channels(hw_params));
501 			ret = -EINVAL;
502 			goto stop_pipeline;
503 		}
504 	} else {
505 		sync_fmt = fmt;
506 	}
507 
508 	ret = snd_usb_lock_shutdown(chip);
509 	if (ret < 0)
510 		goto stop_pipeline;
511 
512 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
513 	if (ret < 0)
514 		goto unlock;
515 
516 	if (subs->data_endpoint) {
517 		if (snd_usb_endpoint_compatible(chip, subs->data_endpoint,
518 						fmt, hw_params))
519 			goto unlock;
520 		close_endpoints(chip, subs);
521 	}
522 
523 	subs->data_endpoint = snd_usb_endpoint_open(chip, fmt, hw_params, false);
524 	if (!subs->data_endpoint) {
525 		ret = -EINVAL;
526 		goto unlock;
527 	}
528 
529 	if (fmt->sync_ep) {
530 		subs->sync_endpoint = snd_usb_endpoint_open(chip, sync_fmt,
531 							    hw_params,
532 							    fmt == sync_fmt);
533 		if (!subs->sync_endpoint) {
534 			ret = -EINVAL;
535 			goto unlock;
536 		}
537 
538 		snd_usb_endpoint_set_sync(chip, subs->data_endpoint,
539 					  subs->sync_endpoint);
540 	}
541 
542 	mutex_lock(&chip->mutex);
543 	subs->cur_audiofmt = fmt;
544 	mutex_unlock(&chip->mutex);
545 
546 	ret = configure_endpoints(chip, subs);
547 
548  unlock:
549 	if (ret < 0)
550 		close_endpoints(chip, subs);
551 
552 	snd_usb_unlock_shutdown(chip);
553  stop_pipeline:
554 	if (ret < 0)
555 		snd_media_stop_pipeline(subs);
556 
557 	return ret;
558 }
559 
560 /*
561  * hw_free callback
562  *
563  * reset the audio format and release the buffer
564  */
565 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
566 {
567 	struct snd_usb_substream *subs = substream->runtime->private_data;
568 	struct snd_usb_audio *chip = subs->stream->chip;
569 
570 	snd_media_stop_pipeline(subs);
571 	mutex_lock(&chip->mutex);
572 	subs->cur_audiofmt = NULL;
573 	mutex_unlock(&chip->mutex);
574 	if (!snd_usb_lock_shutdown(chip)) {
575 		if (stop_endpoints(subs, false))
576 			sync_pending_stops(subs);
577 		close_endpoints(chip, subs);
578 		snd_usb_unlock_shutdown(chip);
579 	}
580 
581 	return 0;
582 }
583 
584 /* free-wheeling mode? (e.g. dmix) */
585 static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime)
586 {
587 	return runtime->stop_threshold > runtime->buffer_size;
588 }
589 
590 /* check whether early start is needed for playback stream */
591 static int lowlatency_playback_available(struct snd_pcm_runtime *runtime,
592 					 struct snd_usb_substream *subs)
593 {
594 	struct snd_usb_audio *chip = subs->stream->chip;
595 
596 	if (subs->direction == SNDRV_PCM_STREAM_CAPTURE)
597 		return false;
598 	/* disabled via module option? */
599 	if (!chip->lowlatency)
600 		return false;
601 	if (in_free_wheeling_mode(runtime))
602 		return false;
603 	/* implicit feedback mode has own operation mode */
604 	if (snd_usb_endpoint_implicit_feedback_sink(subs->data_endpoint))
605 		return false;
606 	return true;
607 }
608 
609 /*
610  * prepare callback
611  *
612  * only a few subtle things...
613  */
614 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
615 {
616 	struct snd_pcm_runtime *runtime = substream->runtime;
617 	struct snd_usb_substream *subs = runtime->private_data;
618 	struct snd_usb_audio *chip = subs->stream->chip;
619 	int ret;
620 
621 	ret = snd_usb_lock_shutdown(chip);
622 	if (ret < 0)
623 		return ret;
624 	if (snd_BUG_ON(!subs->data_endpoint)) {
625 		ret = -EIO;
626 		goto unlock;
627 	}
628 
629 	ret = configure_endpoints(chip, subs);
630 	if (ret < 0)
631 		goto unlock;
632 
633 	/* reset the pointer */
634 	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
635 	subs->inflight_bytes = 0;
636 	subs->hwptr_done = 0;
637 	subs->transfer_done = 0;
638 	subs->last_frame_number = 0;
639 	subs->period_elapsed_pending = 0;
640 	runtime->delay = 0;
641 
642 	subs->lowlatency_playback = lowlatency_playback_available(runtime, subs);
643 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
644 	    !subs->lowlatency_playback)
645 		ret = start_endpoints(subs);
646 
647  unlock:
648 	snd_usb_unlock_shutdown(chip);
649 	return ret;
650 }
651 
652 /*
653  * h/w constraints
654  */
655 
656 #ifdef HW_CONST_DEBUG
657 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
658 #else
659 #define hwc_debug(fmt, args...) do { } while(0)
660 #endif
661 
662 #define MAX_BUFFER_BYTES	(4 * 1024 * 1024)
663 #define MAX_PERIOD_BYTES	(512 * 1024)
664 
665 static const struct snd_pcm_hardware snd_usb_hardware =
666 {
667 	.info =			SNDRV_PCM_INFO_MMAP |
668 				SNDRV_PCM_INFO_MMAP_VALID |
669 				SNDRV_PCM_INFO_BATCH |
670 				SNDRV_PCM_INFO_INTERLEAVED |
671 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
672 				SNDRV_PCM_INFO_PAUSE,
673 	.channels_min =		1,
674 	.channels_max =		256,
675 	.buffer_bytes_max =	MAX_BUFFER_BYTES,
676 	.period_bytes_min =	64,
677 	.period_bytes_max =	MAX_PERIOD_BYTES,
678 	.periods_min =		2,
679 	.periods_max =		1024,
680 };
681 
682 static int hw_check_valid_format(struct snd_usb_substream *subs,
683 				 struct snd_pcm_hw_params *params,
684 				 const struct audioformat *fp)
685 {
686 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
687 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
688 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
689 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
690 	struct snd_mask check_fmts;
691 	unsigned int ptime;
692 
693 	/* check the format */
694 	snd_mask_none(&check_fmts);
695 	check_fmts.bits[0] = (u32)fp->formats;
696 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
697 	snd_mask_intersect(&check_fmts, fmts);
698 	if (snd_mask_empty(&check_fmts)) {
699 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
700 		return 0;
701 	}
702 	/* check the channels */
703 	if (fp->channels < ct->min || fp->channels > ct->max) {
704 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
705 		return 0;
706 	}
707 	/* check the rate is within the range */
708 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
709 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
710 		return 0;
711 	}
712 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
713 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
714 		return 0;
715 	}
716 	/* check whether the period time is >= the data packet interval */
717 	if (subs->speed != USB_SPEED_FULL) {
718 		ptime = 125 * (1 << fp->datainterval);
719 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
720 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
721 			return 0;
722 		}
723 	}
724 	return 1;
725 }
726 
727 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
728 				  unsigned int rmax)
729 {
730 	int changed;
731 
732 	if (rmin > rmax) {
733 		hwc_debug("  --> get empty\n");
734 		it->empty = 1;
735 		return -EINVAL;
736 	}
737 
738 	changed = 0;
739 	if (it->min < rmin) {
740 		it->min = rmin;
741 		it->openmin = 0;
742 		changed = 1;
743 	}
744 	if (it->max > rmax) {
745 		it->max = rmax;
746 		it->openmax = 0;
747 		changed = 1;
748 	}
749 	if (snd_interval_checkempty(it)) {
750 		it->empty = 1;
751 		return -EINVAL;
752 	}
753 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
754 	return changed;
755 }
756 
757 static int hw_rule_rate(struct snd_pcm_hw_params *params,
758 			struct snd_pcm_hw_rule *rule)
759 {
760 	struct snd_usb_substream *subs = rule->private;
761 	struct snd_usb_audio *chip = subs->stream->chip;
762 	const struct audioformat *fp;
763 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
764 	unsigned int rmin, rmax, r;
765 	int i;
766 
767 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
768 	rmin = UINT_MAX;
769 	rmax = 0;
770 	list_for_each_entry(fp, &subs->fmt_list, list) {
771 		if (!hw_check_valid_format(subs, params, fp))
772 			continue;
773 		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
774 		if (r > 0) {
775 			if (!snd_interval_test(it, r))
776 				continue;
777 			rmin = min(rmin, r);
778 			rmax = max(rmax, r);
779 			continue;
780 		}
781 		if (fp->rate_table && fp->nr_rates) {
782 			for (i = 0; i < fp->nr_rates; i++) {
783 				r = fp->rate_table[i];
784 				if (!snd_interval_test(it, r))
785 					continue;
786 				rmin = min(rmin, r);
787 				rmax = max(rmax, r);
788 			}
789 		} else {
790 			rmin = min(rmin, fp->rate_min);
791 			rmax = max(rmax, fp->rate_max);
792 		}
793 	}
794 
795 	return apply_hw_params_minmax(it, rmin, rmax);
796 }
797 
798 
799 static int hw_rule_channels(struct snd_pcm_hw_params *params,
800 			    struct snd_pcm_hw_rule *rule)
801 {
802 	struct snd_usb_substream *subs = rule->private;
803 	const struct audioformat *fp;
804 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
805 	unsigned int rmin, rmax;
806 
807 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
808 	rmin = UINT_MAX;
809 	rmax = 0;
810 	list_for_each_entry(fp, &subs->fmt_list, list) {
811 		if (!hw_check_valid_format(subs, params, fp))
812 			continue;
813 		rmin = min(rmin, fp->channels);
814 		rmax = max(rmax, fp->channels);
815 	}
816 
817 	return apply_hw_params_minmax(it, rmin, rmax);
818 }
819 
820 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
821 {
822 	u32 oldbits[2];
823 	int changed;
824 
825 	oldbits[0] = fmt->bits[0];
826 	oldbits[1] = fmt->bits[1];
827 	fmt->bits[0] &= (u32)fbits;
828 	fmt->bits[1] &= (u32)(fbits >> 32);
829 	if (!fmt->bits[0] && !fmt->bits[1]) {
830 		hwc_debug("  --> get empty\n");
831 		return -EINVAL;
832 	}
833 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
834 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
835 	return changed;
836 }
837 
838 static int hw_rule_format(struct snd_pcm_hw_params *params,
839 			  struct snd_pcm_hw_rule *rule)
840 {
841 	struct snd_usb_substream *subs = rule->private;
842 	const struct audioformat *fp;
843 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
844 	u64 fbits;
845 
846 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
847 	fbits = 0;
848 	list_for_each_entry(fp, &subs->fmt_list, list) {
849 		if (!hw_check_valid_format(subs, params, fp))
850 			continue;
851 		fbits |= fp->formats;
852 	}
853 	return apply_hw_params_format_bits(fmt, fbits);
854 }
855 
856 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
857 			       struct snd_pcm_hw_rule *rule)
858 {
859 	struct snd_usb_substream *subs = rule->private;
860 	const struct audioformat *fp;
861 	struct snd_interval *it;
862 	unsigned char min_datainterval;
863 	unsigned int pmin;
864 
865 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
866 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
867 	min_datainterval = 0xff;
868 	list_for_each_entry(fp, &subs->fmt_list, list) {
869 		if (!hw_check_valid_format(subs, params, fp))
870 			continue;
871 		min_datainterval = min(min_datainterval, fp->datainterval);
872 	}
873 	if (min_datainterval == 0xff) {
874 		hwc_debug("  --> get empty\n");
875 		it->empty = 1;
876 		return -EINVAL;
877 	}
878 	pmin = 125 * (1 << min_datainterval);
879 
880 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
881 }
882 
883 /* get the EP or the sync EP for implicit fb when it's already set up */
884 static const struct snd_usb_endpoint *
885 get_sync_ep_from_substream(struct snd_usb_substream *subs)
886 {
887 	struct snd_usb_audio *chip = subs->stream->chip;
888 	const struct audioformat *fp;
889 	const struct snd_usb_endpoint *ep;
890 
891 	list_for_each_entry(fp, &subs->fmt_list, list) {
892 		ep = snd_usb_get_endpoint(chip, fp->endpoint);
893 		if (ep && ep->cur_audiofmt) {
894 			/* if EP is already opened solely for this substream,
895 			 * we still allow us to change the parameter; otherwise
896 			 * this substream has to follow the existing parameter
897 			 */
898 			if (ep->cur_audiofmt != subs->cur_audiofmt || ep->opened > 1)
899 				return ep;
900 		}
901 		if (!fp->implicit_fb)
902 			continue;
903 		/* for the implicit fb, check the sync ep as well */
904 		ep = snd_usb_get_endpoint(chip, fp->sync_ep);
905 		if (ep && ep->cur_audiofmt)
906 			return ep;
907 	}
908 	return NULL;
909 }
910 
911 /* additional hw constraints for implicit feedback mode */
912 static int hw_rule_format_implicit_fb(struct snd_pcm_hw_params *params,
913 				      struct snd_pcm_hw_rule *rule)
914 {
915 	struct snd_usb_substream *subs = rule->private;
916 	const struct snd_usb_endpoint *ep;
917 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
918 
919 	ep = get_sync_ep_from_substream(subs);
920 	if (!ep)
921 		return 0;
922 
923 	hwc_debug("applying %s\n", __func__);
924 	return apply_hw_params_format_bits(fmt, pcm_format_to_bits(ep->cur_format));
925 }
926 
927 static int hw_rule_rate_implicit_fb(struct snd_pcm_hw_params *params,
928 				    struct snd_pcm_hw_rule *rule)
929 {
930 	struct snd_usb_substream *subs = rule->private;
931 	const struct snd_usb_endpoint *ep;
932 	struct snd_interval *it;
933 
934 	ep = get_sync_ep_from_substream(subs);
935 	if (!ep)
936 		return 0;
937 
938 	hwc_debug("applying %s\n", __func__);
939 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
940 	return apply_hw_params_minmax(it, ep->cur_rate, ep->cur_rate);
941 }
942 
943 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
944 					   struct snd_pcm_hw_rule *rule)
945 {
946 	struct snd_usb_substream *subs = rule->private;
947 	const struct snd_usb_endpoint *ep;
948 	struct snd_interval *it;
949 
950 	ep = get_sync_ep_from_substream(subs);
951 	if (!ep)
952 		return 0;
953 
954 	hwc_debug("applying %s\n", __func__);
955 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
956 	return apply_hw_params_minmax(it, ep->cur_period_frames,
957 				      ep->cur_period_frames);
958 }
959 
960 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
961 				       struct snd_pcm_hw_rule *rule)
962 {
963 	struct snd_usb_substream *subs = rule->private;
964 	const struct snd_usb_endpoint *ep;
965 	struct snd_interval *it;
966 
967 	ep = get_sync_ep_from_substream(subs);
968 	if (!ep)
969 		return 0;
970 
971 	hwc_debug("applying %s\n", __func__);
972 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
973 	return apply_hw_params_minmax(it, ep->cur_buffer_periods,
974 				      ep->cur_buffer_periods);
975 }
976 
977 /* get the adjusted max buffer (or period) bytes that can fit with the
978  * paired format for implicit fb
979  */
980 static unsigned int
981 get_adjusted_max_bytes(struct snd_usb_substream *subs,
982 		       struct snd_usb_substream *pair,
983 		       struct snd_pcm_hw_params *params,
984 		       unsigned int max_bytes,
985 		       bool reverse_map)
986 {
987 	const struct audioformat *fp, *pp;
988 	unsigned int rmax = 0, r;
989 
990 	list_for_each_entry(fp, &subs->fmt_list, list) {
991 		if (!fp->implicit_fb)
992 			continue;
993 		if (!reverse_map &&
994 		    !hw_check_valid_format(subs, params, fp))
995 			continue;
996 		list_for_each_entry(pp, &pair->fmt_list, list) {
997 			if (pp->iface != fp->sync_iface ||
998 			    pp->altsetting != fp->sync_altsetting ||
999 			    pp->ep_idx != fp->sync_ep_idx)
1000 				continue;
1001 			if (reverse_map &&
1002 			    !hw_check_valid_format(pair, params, pp))
1003 				break;
1004 			if (!reverse_map && pp->channels > fp->channels)
1005 				r = max_bytes * fp->channels / pp->channels;
1006 			else if (reverse_map && pp->channels < fp->channels)
1007 				r = max_bytes * pp->channels / fp->channels;
1008 			else
1009 				r = max_bytes;
1010 			rmax = max(rmax, r);
1011 			break;
1012 		}
1013 	}
1014 	return rmax;
1015 }
1016 
1017 /* Reduce the period or buffer bytes depending on the paired substream;
1018  * when a paired configuration for implicit fb has a higher number of channels,
1019  * we need to reduce the max size accordingly, otherwise it may become unusable
1020  */
1021 static int hw_rule_bytes_implicit_fb(struct snd_pcm_hw_params *params,
1022 				     struct snd_pcm_hw_rule *rule)
1023 {
1024 	struct snd_usb_substream *subs = rule->private;
1025 	struct snd_usb_substream *pair;
1026 	struct snd_interval *it;
1027 	unsigned int max_bytes;
1028 	unsigned int rmax;
1029 
1030 	pair = &subs->stream->substream[!subs->direction];
1031 	if (!pair->ep_num)
1032 		return 0;
1033 
1034 	if (rule->var == SNDRV_PCM_HW_PARAM_PERIOD_BYTES)
1035 		max_bytes = MAX_PERIOD_BYTES;
1036 	else
1037 		max_bytes = MAX_BUFFER_BYTES;
1038 
1039 	rmax = get_adjusted_max_bytes(subs, pair, params, max_bytes, false);
1040 	if (!rmax)
1041 		rmax = get_adjusted_max_bytes(pair, subs, params, max_bytes, true);
1042 	if (!rmax)
1043 		return 0;
1044 
1045 	it = hw_param_interval(params, rule->var);
1046 	return apply_hw_params_minmax(it, 0, rmax);
1047 }
1048 
1049 /*
1050  * set up the runtime hardware information.
1051  */
1052 
1053 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1054 {
1055 	const struct audioformat *fp;
1056 	unsigned int pt, ptmin;
1057 	int param_period_time_if_needed = -1;
1058 	int err;
1059 
1060 	runtime->hw.formats = subs->formats;
1061 
1062 	runtime->hw.rate_min = 0x7fffffff;
1063 	runtime->hw.rate_max = 0;
1064 	runtime->hw.channels_min = 256;
1065 	runtime->hw.channels_max = 0;
1066 	runtime->hw.rates = 0;
1067 	ptmin = UINT_MAX;
1068 	/* check min/max rates and channels */
1069 	list_for_each_entry(fp, &subs->fmt_list, list) {
1070 		runtime->hw.rates |= fp->rates;
1071 		if (runtime->hw.rate_min > fp->rate_min)
1072 			runtime->hw.rate_min = fp->rate_min;
1073 		if (runtime->hw.rate_max < fp->rate_max)
1074 			runtime->hw.rate_max = fp->rate_max;
1075 		if (runtime->hw.channels_min > fp->channels)
1076 			runtime->hw.channels_min = fp->channels;
1077 		if (runtime->hw.channels_max < fp->channels)
1078 			runtime->hw.channels_max = fp->channels;
1079 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1080 			/* FIXME: there might be more than one audio formats... */
1081 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1082 				fp->frame_size;
1083 		}
1084 		pt = 125 * (1 << fp->datainterval);
1085 		ptmin = min(ptmin, pt);
1086 	}
1087 
1088 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1089 	if (subs->speed == USB_SPEED_FULL)
1090 		/* full speed devices have fixed data packet interval */
1091 		ptmin = 1000;
1092 	if (ptmin == 1000)
1093 		/* if period time doesn't go below 1 ms, no rules needed */
1094 		param_period_time_if_needed = -1;
1095 
1096 	err = snd_pcm_hw_constraint_minmax(runtime,
1097 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1098 					   ptmin, UINT_MAX);
1099 	if (err < 0)
1100 		return err;
1101 
1102 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1103 				  hw_rule_rate, subs,
1104 				  SNDRV_PCM_HW_PARAM_RATE,
1105 				  SNDRV_PCM_HW_PARAM_FORMAT,
1106 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1107 				  param_period_time_if_needed,
1108 				  -1);
1109 	if (err < 0)
1110 		return err;
1111 
1112 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1113 				  hw_rule_channels, subs,
1114 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1115 				  SNDRV_PCM_HW_PARAM_FORMAT,
1116 				  SNDRV_PCM_HW_PARAM_RATE,
1117 				  param_period_time_if_needed,
1118 				  -1);
1119 	if (err < 0)
1120 		return err;
1121 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1122 				  hw_rule_format, subs,
1123 				  SNDRV_PCM_HW_PARAM_FORMAT,
1124 				  SNDRV_PCM_HW_PARAM_RATE,
1125 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1126 				  param_period_time_if_needed,
1127 				  -1);
1128 	if (err < 0)
1129 		return err;
1130 	if (param_period_time_if_needed >= 0) {
1131 		err = snd_pcm_hw_rule_add(runtime, 0,
1132 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1133 					  hw_rule_period_time, subs,
1134 					  SNDRV_PCM_HW_PARAM_FORMAT,
1135 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1136 					  SNDRV_PCM_HW_PARAM_RATE,
1137 					  -1);
1138 		if (err < 0)
1139 			return err;
1140 	}
1141 
1142 	/* additional hw constraints for implicit fb */
1143 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1144 				  hw_rule_format_implicit_fb, subs,
1145 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1146 	if (err < 0)
1147 		return err;
1148 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1149 				  hw_rule_rate_implicit_fb, subs,
1150 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1151 	if (err < 0)
1152 		return err;
1153 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1154 				  hw_rule_period_size_implicit_fb, subs,
1155 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1156 	if (err < 0)
1157 		return err;
1158 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1159 				  hw_rule_periods_implicit_fb, subs,
1160 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1161 	if (err < 0)
1162 		return err;
1163 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
1164 				  hw_rule_bytes_implicit_fb, subs,
1165 				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
1166 	if (err < 0)
1167 		return err;
1168 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
1169 				  hw_rule_bytes_implicit_fb, subs,
1170 				  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
1171 	if (err < 0)
1172 		return err;
1173 
1174 	list_for_each_entry(fp, &subs->fmt_list, list) {
1175 		if (fp->implicit_fb) {
1176 			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1177 			break;
1178 		}
1179 	}
1180 
1181 	return 0;
1182 }
1183 
1184 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1185 {
1186 	int direction = substream->stream;
1187 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1188 	struct snd_pcm_runtime *runtime = substream->runtime;
1189 	struct snd_usb_substream *subs = &as->substream[direction];
1190 	int ret;
1191 
1192 	runtime->hw = snd_usb_hardware;
1193 	/* need an explicit sync to catch applptr update in low-latency mode */
1194 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1195 	    as->chip->lowlatency)
1196 		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1197 	runtime->private_data = subs;
1198 	subs->pcm_substream = substream;
1199 	/* runtime PM is also done there */
1200 
1201 	/* initialize DSD/DOP context */
1202 	subs->dsd_dop.byte_idx = 0;
1203 	subs->dsd_dop.channel = 0;
1204 	subs->dsd_dop.marker = 1;
1205 
1206 	ret = setup_hw_info(runtime, subs);
1207 	if (ret < 0)
1208 		return ret;
1209 	ret = snd_usb_autoresume(subs->stream->chip);
1210 	if (ret < 0)
1211 		return ret;
1212 	ret = snd_media_stream_init(subs, as->pcm, direction);
1213 	if (ret < 0)
1214 		snd_usb_autosuspend(subs->stream->chip);
1215 	return ret;
1216 }
1217 
1218 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1219 {
1220 	int direction = substream->stream;
1221 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1222 	struct snd_usb_substream *subs = &as->substream[direction];
1223 	int ret;
1224 
1225 	snd_media_stop_pipeline(subs);
1226 
1227 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1228 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1229 		snd_usb_unlock_shutdown(subs->stream->chip);
1230 		if (ret < 0)
1231 			return ret;
1232 	}
1233 
1234 	subs->pcm_substream = NULL;
1235 	snd_usb_autosuspend(subs->stream->chip);
1236 
1237 	return 0;
1238 }
1239 
1240 /* Since a URB can handle only a single linear buffer, we must use double
1241  * buffering when the data to be transferred overflows the buffer boundary.
1242  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1243  * for all URBs.
1244  */
1245 static void retire_capture_urb(struct snd_usb_substream *subs,
1246 			       struct urb *urb)
1247 {
1248 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1249 	unsigned int stride, frames, bytes, oldptr;
1250 	int i, period_elapsed = 0;
1251 	unsigned long flags;
1252 	unsigned char *cp;
1253 	int current_frame_number;
1254 
1255 	/* read frame number here, update pointer in critical section */
1256 	current_frame_number = usb_get_current_frame_number(subs->dev);
1257 
1258 	stride = runtime->frame_bits >> 3;
1259 
1260 	for (i = 0; i < urb->number_of_packets; i++) {
1261 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1262 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1263 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1264 				i, urb->iso_frame_desc[i].status);
1265 			// continue;
1266 		}
1267 		bytes = urb->iso_frame_desc[i].actual_length;
1268 		if (subs->stream_offset_adj > 0) {
1269 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1270 			cp += adj;
1271 			bytes -= adj;
1272 			subs->stream_offset_adj -= adj;
1273 		}
1274 		frames = bytes / stride;
1275 		if (!subs->txfr_quirk)
1276 			bytes = frames * stride;
1277 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1278 			int oldbytes = bytes;
1279 			bytes = frames * stride;
1280 			dev_warn_ratelimited(&subs->dev->dev,
1281 				 "Corrected urb data len. %d->%d\n",
1282 							oldbytes, bytes);
1283 		}
1284 		/* update the current pointer */
1285 		spin_lock_irqsave(&subs->lock, flags);
1286 		oldptr = subs->hwptr_done;
1287 		subs->hwptr_done += bytes;
1288 		if (subs->hwptr_done >= subs->buffer_bytes)
1289 			subs->hwptr_done -= subs->buffer_bytes;
1290 		frames = (bytes + (oldptr % stride)) / stride;
1291 		subs->transfer_done += frames;
1292 		if (subs->transfer_done >= runtime->period_size) {
1293 			subs->transfer_done -= runtime->period_size;
1294 			period_elapsed = 1;
1295 		}
1296 
1297 		/* realign last_frame_number */
1298 		subs->last_frame_number = current_frame_number;
1299 
1300 		spin_unlock_irqrestore(&subs->lock, flags);
1301 		/* copy a data chunk */
1302 		if (oldptr + bytes > subs->buffer_bytes) {
1303 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1304 
1305 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1306 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1307 		} else {
1308 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1309 		}
1310 	}
1311 
1312 	if (period_elapsed)
1313 		snd_pcm_period_elapsed(subs->pcm_substream);
1314 }
1315 
1316 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1317 				  struct urb *urb, unsigned int bytes)
1318 {
1319 	struct snd_urb_ctx *ctx = urb->context;
1320 
1321 	ctx->queued += bytes;
1322 	subs->inflight_bytes += bytes;
1323 	subs->hwptr_done += bytes;
1324 	if (subs->hwptr_done >= subs->buffer_bytes)
1325 		subs->hwptr_done -= subs->buffer_bytes;
1326 }
1327 
1328 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1329 					     struct urb *urb, unsigned int bytes)
1330 {
1331 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1332 	unsigned int dst_idx = 0;
1333 	unsigned int src_idx = subs->hwptr_done;
1334 	unsigned int wrap = subs->buffer_bytes;
1335 	u8 *dst = urb->transfer_buffer;
1336 	u8 *src = runtime->dma_area;
1337 	u8 marker[] = { 0x05, 0xfa };
1338 	unsigned int queued = 0;
1339 
1340 	/*
1341 	 * The DSP DOP format defines a way to transport DSD samples over
1342 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1343 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1344 	 * 2 additional bytes of actual payload. The whole frame is stored
1345 	 * LSB.
1346 	 *
1347 	 * Hence, for a stereo transport, the buffer layout looks like this,
1348 	 * where L refers to left channel samples and R to right.
1349 	 *
1350 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1351 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1352 	 *   .....
1353 	 *
1354 	 */
1355 
1356 	while (bytes--) {
1357 		if (++subs->dsd_dop.byte_idx == 3) {
1358 			/* frame boundary? */
1359 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1360 			src_idx += 2;
1361 			subs->dsd_dop.byte_idx = 0;
1362 
1363 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1364 				/* alternate the marker */
1365 				subs->dsd_dop.marker++;
1366 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1367 				subs->dsd_dop.channel = 0;
1368 			}
1369 		} else {
1370 			/* stuff the DSD payload */
1371 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1372 
1373 			if (subs->cur_audiofmt->dsd_bitrev)
1374 				dst[dst_idx++] = bitrev8(src[idx]);
1375 			else
1376 				dst[dst_idx++] = src[idx];
1377 			queued++;
1378 		}
1379 	}
1380 
1381 	urb_ctx_queue_advance(subs, urb, queued);
1382 }
1383 
1384 /* copy bit-reversed bytes onto transfer buffer */
1385 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1386 					 struct urb *urb, unsigned int bytes)
1387 {
1388 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1389 	const u8 *src = runtime->dma_area;
1390 	u8 *buf = urb->transfer_buffer;
1391 	int i, ofs = subs->hwptr_done;
1392 
1393 	for (i = 0; i < bytes; i++) {
1394 		*buf++ = bitrev8(src[ofs]);
1395 		if (++ofs >= subs->buffer_bytes)
1396 			ofs = 0;
1397 	}
1398 
1399 	urb_ctx_queue_advance(subs, urb, bytes);
1400 }
1401 
1402 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1403 			int offset, int stride, unsigned int bytes)
1404 {
1405 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1406 
1407 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1408 		/* err, the transferred area goes over buffer boundary. */
1409 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1410 
1411 		memcpy(urb->transfer_buffer + offset,
1412 		       runtime->dma_area + subs->hwptr_done, bytes1);
1413 		memcpy(urb->transfer_buffer + offset + bytes1,
1414 		       runtime->dma_area, bytes - bytes1);
1415 	} else {
1416 		memcpy(urb->transfer_buffer + offset,
1417 		       runtime->dma_area + subs->hwptr_done, bytes);
1418 	}
1419 
1420 	urb_ctx_queue_advance(subs, urb, bytes);
1421 }
1422 
1423 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1424 				      struct urb *urb, int stride,
1425 				      unsigned int bytes)
1426 {
1427 	__le32 packet_length;
1428 	int i;
1429 
1430 	/* Put __le32 length descriptor at start of each packet. */
1431 	for (i = 0; i < urb->number_of_packets; i++) {
1432 		unsigned int length = urb->iso_frame_desc[i].length;
1433 		unsigned int offset = urb->iso_frame_desc[i].offset;
1434 
1435 		packet_length = cpu_to_le32(length);
1436 		offset += i * sizeof(packet_length);
1437 		urb->iso_frame_desc[i].offset = offset;
1438 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1439 		memcpy(urb->transfer_buffer + offset,
1440 		       &packet_length, sizeof(packet_length));
1441 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1442 			    stride, length);
1443 	}
1444 	/* Adjust transfer size accordingly. */
1445 	bytes += urb->number_of_packets * sizeof(packet_length);
1446 	return bytes;
1447 }
1448 
1449 static int prepare_playback_urb(struct snd_usb_substream *subs,
1450 				struct urb *urb,
1451 				bool in_stream_lock)
1452 {
1453 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1454 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1455 	struct snd_urb_ctx *ctx = urb->context;
1456 	unsigned int frames, bytes;
1457 	int counts;
1458 	unsigned int transfer_done, frame_limit, avail = 0;
1459 	int i, stride, period_elapsed = 0;
1460 	unsigned long flags;
1461 	int err = 0;
1462 
1463 	stride = ep->stride;
1464 
1465 	frames = 0;
1466 	ctx->queued = 0;
1467 	urb->number_of_packets = 0;
1468 
1469 	spin_lock_irqsave(&subs->lock, flags);
1470 	frame_limit = subs->frame_limit + ep->max_urb_frames;
1471 	transfer_done = subs->transfer_done;
1472 
1473 	if (subs->lowlatency_playback &&
1474 	    runtime->status->state != SNDRV_PCM_STATE_DRAINING) {
1475 		unsigned int hwptr = subs->hwptr_done / stride;
1476 
1477 		/* calculate the byte offset-in-buffer of the appl_ptr */
1478 		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1479 			% runtime->buffer_size;
1480 		if (avail <= hwptr)
1481 			avail += runtime->buffer_size;
1482 		avail -= hwptr;
1483 	}
1484 
1485 	for (i = 0; i < ctx->packets; i++) {
1486 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1487 		if (counts < 0)
1488 			break;
1489 		/* set up descriptor */
1490 		urb->iso_frame_desc[i].offset = frames * stride;
1491 		urb->iso_frame_desc[i].length = counts * stride;
1492 		frames += counts;
1493 		avail -= counts;
1494 		urb->number_of_packets++;
1495 		transfer_done += counts;
1496 		if (transfer_done >= runtime->period_size) {
1497 			transfer_done -= runtime->period_size;
1498 			frame_limit = 0;
1499 			period_elapsed = 1;
1500 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1501 				if (transfer_done > 0) {
1502 					/* FIXME: fill-max mode is not
1503 					 * supported yet */
1504 					frames -= transfer_done;
1505 					counts -= transfer_done;
1506 					urb->iso_frame_desc[i].length =
1507 						counts * stride;
1508 					transfer_done = 0;
1509 				}
1510 				i++;
1511 				if (i < ctx->packets) {
1512 					/* add a transfer delimiter */
1513 					urb->iso_frame_desc[i].offset =
1514 						frames * stride;
1515 					urb->iso_frame_desc[i].length = 0;
1516 					urb->number_of_packets++;
1517 				}
1518 				break;
1519 			}
1520 		}
1521 		/* finish at the period boundary or after enough frames */
1522 		if ((period_elapsed || transfer_done >= frame_limit) &&
1523 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1524 			break;
1525 	}
1526 
1527 	if (!frames) {
1528 		err = -EAGAIN;
1529 		goto unlock;
1530 	}
1531 
1532 	bytes = frames * stride;
1533 	subs->transfer_done = transfer_done;
1534 	subs->frame_limit = frame_limit;
1535 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1536 		     subs->cur_audiofmt->dsd_dop)) {
1537 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1538 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1539 			   subs->cur_audiofmt->dsd_bitrev)) {
1540 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1541 	} else {
1542 		/* usual PCM */
1543 		if (!subs->tx_length_quirk)
1544 			copy_to_urb(subs, urb, 0, stride, bytes);
1545 		else
1546 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1547 			/* bytes is now amount of outgoing data */
1548 	}
1549 
1550 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1551 
1552 	if (subs->trigger_tstamp_pending_update) {
1553 		/* this is the first actual URB submitted,
1554 		 * update trigger timestamp to reflect actual start time
1555 		 */
1556 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1557 		subs->trigger_tstamp_pending_update = false;
1558 	}
1559 
1560 	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1561 		subs->period_elapsed_pending = 1;
1562 		period_elapsed = 0;
1563 	}
1564 
1565  unlock:
1566 	spin_unlock_irqrestore(&subs->lock, flags);
1567 	if (err < 0)
1568 		return err;
1569 	urb->transfer_buffer_length = bytes;
1570 	if (period_elapsed) {
1571 		if (in_stream_lock)
1572 			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1573 		else
1574 			snd_pcm_period_elapsed(subs->pcm_substream);
1575 	}
1576 	return 0;
1577 }
1578 
1579 /*
1580  * process after playback data complete
1581  * - decrease the delay count again
1582  */
1583 static void retire_playback_urb(struct snd_usb_substream *subs,
1584 			       struct urb *urb)
1585 {
1586 	unsigned long flags;
1587 	struct snd_urb_ctx *ctx = urb->context;
1588 	bool period_elapsed = false;
1589 
1590 	spin_lock_irqsave(&subs->lock, flags);
1591 	if (ctx->queued) {
1592 		if (subs->inflight_bytes >= ctx->queued)
1593 			subs->inflight_bytes -= ctx->queued;
1594 		else
1595 			subs->inflight_bytes = 0;
1596 	}
1597 
1598 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1599 	if (subs->running) {
1600 		period_elapsed = subs->period_elapsed_pending;
1601 		subs->period_elapsed_pending = 0;
1602 	}
1603 	spin_unlock_irqrestore(&subs->lock, flags);
1604 	if (period_elapsed)
1605 		snd_pcm_period_elapsed(subs->pcm_substream);
1606 }
1607 
1608 /* PCM ack callback for the playback stream;
1609  * this plays a role only when the stream is running in low-latency mode.
1610  */
1611 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1612 {
1613 	struct snd_usb_substream *subs = substream->runtime->private_data;
1614 	struct snd_usb_endpoint *ep;
1615 
1616 	if (!subs->lowlatency_playback || !subs->running)
1617 		return 0;
1618 	ep = subs->data_endpoint;
1619 	if (!ep)
1620 		return 0;
1621 	/* When no more in-flight URBs available, try to process the pending
1622 	 * outputs here
1623 	 */
1624 	if (!ep->active_mask)
1625 		snd_usb_queue_pending_output_urbs(ep, true);
1626 	return 0;
1627 }
1628 
1629 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1630 					      int cmd)
1631 {
1632 	struct snd_usb_substream *subs = substream->runtime->private_data;
1633 	int err;
1634 
1635 	switch (cmd) {
1636 	case SNDRV_PCM_TRIGGER_START:
1637 		subs->trigger_tstamp_pending_update = true;
1638 		fallthrough;
1639 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1640 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1641 					      prepare_playback_urb,
1642 					      retire_playback_urb,
1643 					      subs);
1644 		if (subs->lowlatency_playback &&
1645 		    cmd == SNDRV_PCM_TRIGGER_START) {
1646 			if (in_free_wheeling_mode(substream->runtime))
1647 				subs->lowlatency_playback = false;
1648 			err = start_endpoints(subs);
1649 			if (err < 0) {
1650 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1651 							      NULL, NULL, NULL);
1652 				return err;
1653 			}
1654 		}
1655 		subs->running = 1;
1656 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1657 			subs->cur_audiofmt->iface,
1658 			subs->cur_audiofmt->altsetting);
1659 		return 0;
1660 	case SNDRV_PCM_TRIGGER_SUSPEND:
1661 	case SNDRV_PCM_TRIGGER_STOP:
1662 		stop_endpoints(subs, substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING);
1663 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1664 					      NULL, NULL, NULL);
1665 		subs->running = 0;
1666 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1667 			subs->cur_audiofmt->iface,
1668 			subs->cur_audiofmt->altsetting);
1669 		return 0;
1670 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1671 		/* keep retire_data_urb for delay calculation */
1672 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1673 					      NULL,
1674 					      retire_playback_urb,
1675 					      subs);
1676 		subs->running = 0;
1677 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1678 			subs->cur_audiofmt->iface,
1679 			subs->cur_audiofmt->altsetting);
1680 		return 0;
1681 	}
1682 
1683 	return -EINVAL;
1684 }
1685 
1686 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1687 					     int cmd)
1688 {
1689 	int err;
1690 	struct snd_usb_substream *subs = substream->runtime->private_data;
1691 
1692 	switch (cmd) {
1693 	case SNDRV_PCM_TRIGGER_START:
1694 		err = start_endpoints(subs);
1695 		if (err < 0)
1696 			return err;
1697 		fallthrough;
1698 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1699 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1700 					      NULL, retire_capture_urb,
1701 					      subs);
1702 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1703 		subs->running = 1;
1704 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1705 			subs->cur_audiofmt->iface,
1706 			subs->cur_audiofmt->altsetting);
1707 		return 0;
1708 	case SNDRV_PCM_TRIGGER_SUSPEND:
1709 	case SNDRV_PCM_TRIGGER_STOP:
1710 		stop_endpoints(subs, false);
1711 		fallthrough;
1712 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1713 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1714 					      NULL, NULL, NULL);
1715 		subs->running = 0;
1716 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1717 			subs->cur_audiofmt->iface,
1718 			subs->cur_audiofmt->altsetting);
1719 		return 0;
1720 	}
1721 
1722 	return -EINVAL;
1723 }
1724 
1725 static const struct snd_pcm_ops snd_usb_playback_ops = {
1726 	.open =		snd_usb_pcm_open,
1727 	.close =	snd_usb_pcm_close,
1728 	.hw_params =	snd_usb_hw_params,
1729 	.hw_free =	snd_usb_hw_free,
1730 	.prepare =	snd_usb_pcm_prepare,
1731 	.trigger =	snd_usb_substream_playback_trigger,
1732 	.sync_stop =	snd_usb_pcm_sync_stop,
1733 	.pointer =	snd_usb_pcm_pointer,
1734 	.ack =		snd_usb_pcm_playback_ack,
1735 };
1736 
1737 static const struct snd_pcm_ops snd_usb_capture_ops = {
1738 	.open =		snd_usb_pcm_open,
1739 	.close =	snd_usb_pcm_close,
1740 	.hw_params =	snd_usb_hw_params,
1741 	.hw_free =	snd_usb_hw_free,
1742 	.prepare =	snd_usb_pcm_prepare,
1743 	.trigger =	snd_usb_substream_capture_trigger,
1744 	.sync_stop =	snd_usb_pcm_sync_stop,
1745 	.pointer =	snd_usb_pcm_pointer,
1746 };
1747 
1748 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1749 {
1750 	const struct snd_pcm_ops *ops;
1751 
1752 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1753 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1754 	snd_pcm_set_ops(pcm, stream, ops);
1755 }
1756 
1757 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1758 {
1759 	struct snd_pcm *pcm = subs->stream->pcm;
1760 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1761 	struct device *dev = subs->dev->bus->sysdev;
1762 
1763 	if (snd_usb_use_vmalloc)
1764 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1765 					   NULL, 0, 0);
1766 	else
1767 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1768 					   dev, 64*1024, 512*1024);
1769 }
1770