xref: /openbmc/linux/sound/usb/pcm.c (revision 0a94608f)
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 static const struct snd_pcm_hardware snd_usb_hardware =
663 {
664 	.info =			SNDRV_PCM_INFO_MMAP |
665 				SNDRV_PCM_INFO_MMAP_VALID |
666 				SNDRV_PCM_INFO_BATCH |
667 				SNDRV_PCM_INFO_INTERLEAVED |
668 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
669 				SNDRV_PCM_INFO_PAUSE,
670 	.channels_min =		1,
671 	.channels_max =		256,
672 	.buffer_bytes_max =	INT_MAX, /* limited by BUFFER_TIME later */
673 	.period_bytes_min =	64,
674 	.period_bytes_max =	INT_MAX, /* limited by PERIOD_TIME later */
675 	.periods_min =		2,
676 	.periods_max =		1024,
677 };
678 
679 static int hw_check_valid_format(struct snd_usb_substream *subs,
680 				 struct snd_pcm_hw_params *params,
681 				 const struct audioformat *fp)
682 {
683 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
684 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
685 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
686 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
687 	struct snd_mask check_fmts;
688 	unsigned int ptime;
689 
690 	/* check the format */
691 	snd_mask_none(&check_fmts);
692 	check_fmts.bits[0] = (u32)fp->formats;
693 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
694 	snd_mask_intersect(&check_fmts, fmts);
695 	if (snd_mask_empty(&check_fmts)) {
696 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
697 		return 0;
698 	}
699 	/* check the channels */
700 	if (fp->channels < ct->min || fp->channels > ct->max) {
701 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
702 		return 0;
703 	}
704 	/* check the rate is within the range */
705 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
706 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
707 		return 0;
708 	}
709 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
710 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
711 		return 0;
712 	}
713 	/* check whether the period time is >= the data packet interval */
714 	if (subs->speed != USB_SPEED_FULL) {
715 		ptime = 125 * (1 << fp->datainterval);
716 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
717 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
718 			return 0;
719 		}
720 	}
721 	return 1;
722 }
723 
724 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
725 				  unsigned int rmax)
726 {
727 	int changed;
728 
729 	if (rmin > rmax) {
730 		hwc_debug("  --> get empty\n");
731 		it->empty = 1;
732 		return -EINVAL;
733 	}
734 
735 	changed = 0;
736 	if (it->min < rmin) {
737 		it->min = rmin;
738 		it->openmin = 0;
739 		changed = 1;
740 	}
741 	if (it->max > rmax) {
742 		it->max = rmax;
743 		it->openmax = 0;
744 		changed = 1;
745 	}
746 	if (snd_interval_checkempty(it)) {
747 		it->empty = 1;
748 		return -EINVAL;
749 	}
750 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
751 	return changed;
752 }
753 
754 static int hw_rule_rate(struct snd_pcm_hw_params *params,
755 			struct snd_pcm_hw_rule *rule)
756 {
757 	struct snd_usb_substream *subs = rule->private;
758 	struct snd_usb_audio *chip = subs->stream->chip;
759 	const struct audioformat *fp;
760 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
761 	unsigned int rmin, rmax, r;
762 	int i;
763 
764 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
765 	rmin = UINT_MAX;
766 	rmax = 0;
767 	list_for_each_entry(fp, &subs->fmt_list, list) {
768 		if (!hw_check_valid_format(subs, params, fp))
769 			continue;
770 		r = snd_usb_endpoint_get_clock_rate(chip, fp->clock);
771 		if (r > 0) {
772 			if (!snd_interval_test(it, r))
773 				continue;
774 			rmin = min(rmin, r);
775 			rmax = max(rmax, r);
776 			continue;
777 		}
778 		if (fp->rate_table && fp->nr_rates) {
779 			for (i = 0; i < fp->nr_rates; i++) {
780 				r = fp->rate_table[i];
781 				if (!snd_interval_test(it, r))
782 					continue;
783 				rmin = min(rmin, r);
784 				rmax = max(rmax, r);
785 			}
786 		} else {
787 			rmin = min(rmin, fp->rate_min);
788 			rmax = max(rmax, fp->rate_max);
789 		}
790 	}
791 
792 	return apply_hw_params_minmax(it, rmin, rmax);
793 }
794 
795 
796 static int hw_rule_channels(struct snd_pcm_hw_params *params,
797 			    struct snd_pcm_hw_rule *rule)
798 {
799 	struct snd_usb_substream *subs = rule->private;
800 	const struct audioformat *fp;
801 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
802 	unsigned int rmin, rmax;
803 
804 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
805 	rmin = UINT_MAX;
806 	rmax = 0;
807 	list_for_each_entry(fp, &subs->fmt_list, list) {
808 		if (!hw_check_valid_format(subs, params, fp))
809 			continue;
810 		rmin = min(rmin, fp->channels);
811 		rmax = max(rmax, fp->channels);
812 	}
813 
814 	return apply_hw_params_minmax(it, rmin, rmax);
815 }
816 
817 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
818 {
819 	u32 oldbits[2];
820 	int changed;
821 
822 	oldbits[0] = fmt->bits[0];
823 	oldbits[1] = fmt->bits[1];
824 	fmt->bits[0] &= (u32)fbits;
825 	fmt->bits[1] &= (u32)(fbits >> 32);
826 	if (!fmt->bits[0] && !fmt->bits[1]) {
827 		hwc_debug("  --> get empty\n");
828 		return -EINVAL;
829 	}
830 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
831 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
832 	return changed;
833 }
834 
835 static int hw_rule_format(struct snd_pcm_hw_params *params,
836 			  struct snd_pcm_hw_rule *rule)
837 {
838 	struct snd_usb_substream *subs = rule->private;
839 	const struct audioformat *fp;
840 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
841 	u64 fbits;
842 
843 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
844 	fbits = 0;
845 	list_for_each_entry(fp, &subs->fmt_list, list) {
846 		if (!hw_check_valid_format(subs, params, fp))
847 			continue;
848 		fbits |= fp->formats;
849 	}
850 	return apply_hw_params_format_bits(fmt, fbits);
851 }
852 
853 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
854 			       struct snd_pcm_hw_rule *rule)
855 {
856 	struct snd_usb_substream *subs = rule->private;
857 	const struct audioformat *fp;
858 	struct snd_interval *it;
859 	unsigned char min_datainterval;
860 	unsigned int pmin;
861 
862 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
863 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
864 	min_datainterval = 0xff;
865 	list_for_each_entry(fp, &subs->fmt_list, list) {
866 		if (!hw_check_valid_format(subs, params, fp))
867 			continue;
868 		min_datainterval = min(min_datainterval, fp->datainterval);
869 	}
870 	if (min_datainterval == 0xff) {
871 		hwc_debug("  --> get empty\n");
872 		it->empty = 1;
873 		return -EINVAL;
874 	}
875 	pmin = 125 * (1 << min_datainterval);
876 
877 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
878 }
879 
880 /* get the EP or the sync EP for implicit fb when it's already set up */
881 static const struct snd_usb_endpoint *
882 get_sync_ep_from_substream(struct snd_usb_substream *subs)
883 {
884 	struct snd_usb_audio *chip = subs->stream->chip;
885 	const struct audioformat *fp;
886 	const struct snd_usb_endpoint *ep;
887 
888 	list_for_each_entry(fp, &subs->fmt_list, list) {
889 		ep = snd_usb_get_endpoint(chip, fp->endpoint);
890 		if (ep && ep->cur_audiofmt) {
891 			/* if EP is already opened solely for this substream,
892 			 * we still allow us to change the parameter; otherwise
893 			 * this substream has to follow the existing parameter
894 			 */
895 			if (ep->cur_audiofmt != subs->cur_audiofmt || ep->opened > 1)
896 				return ep;
897 		}
898 		if (!fp->implicit_fb)
899 			continue;
900 		/* for the implicit fb, check the sync ep as well */
901 		ep = snd_usb_get_endpoint(chip, fp->sync_ep);
902 		if (ep && ep->cur_audiofmt)
903 			return ep;
904 	}
905 	return NULL;
906 }
907 
908 /* additional hw constraints for implicit feedback mode */
909 static int hw_rule_format_implicit_fb(struct snd_pcm_hw_params *params,
910 				      struct snd_pcm_hw_rule *rule)
911 {
912 	struct snd_usb_substream *subs = rule->private;
913 	const struct snd_usb_endpoint *ep;
914 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
915 
916 	ep = get_sync_ep_from_substream(subs);
917 	if (!ep)
918 		return 0;
919 
920 	hwc_debug("applying %s\n", __func__);
921 	return apply_hw_params_format_bits(fmt, pcm_format_to_bits(ep->cur_format));
922 }
923 
924 static int hw_rule_rate_implicit_fb(struct snd_pcm_hw_params *params,
925 				    struct snd_pcm_hw_rule *rule)
926 {
927 	struct snd_usb_substream *subs = rule->private;
928 	const struct snd_usb_endpoint *ep;
929 	struct snd_interval *it;
930 
931 	ep = get_sync_ep_from_substream(subs);
932 	if (!ep)
933 		return 0;
934 
935 	hwc_debug("applying %s\n", __func__);
936 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
937 	return apply_hw_params_minmax(it, ep->cur_rate, ep->cur_rate);
938 }
939 
940 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
941 					   struct snd_pcm_hw_rule *rule)
942 {
943 	struct snd_usb_substream *subs = rule->private;
944 	const struct snd_usb_endpoint *ep;
945 	struct snd_interval *it;
946 
947 	ep = get_sync_ep_from_substream(subs);
948 	if (!ep)
949 		return 0;
950 
951 	hwc_debug("applying %s\n", __func__);
952 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
953 	return apply_hw_params_minmax(it, ep->cur_period_frames,
954 				      ep->cur_period_frames);
955 }
956 
957 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
958 				       struct snd_pcm_hw_rule *rule)
959 {
960 	struct snd_usb_substream *subs = rule->private;
961 	const struct snd_usb_endpoint *ep;
962 	struct snd_interval *it;
963 
964 	ep = get_sync_ep_from_substream(subs);
965 	if (!ep)
966 		return 0;
967 
968 	hwc_debug("applying %s\n", __func__);
969 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
970 	return apply_hw_params_minmax(it, ep->cur_buffer_periods,
971 				      ep->cur_buffer_periods);
972 }
973 
974 /*
975  * set up the runtime hardware information.
976  */
977 
978 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
979 {
980 	const struct audioformat *fp;
981 	unsigned int pt, ptmin;
982 	int param_period_time_if_needed = -1;
983 	int err;
984 
985 	runtime->hw.formats = subs->formats;
986 
987 	runtime->hw.rate_min = 0x7fffffff;
988 	runtime->hw.rate_max = 0;
989 	runtime->hw.channels_min = 256;
990 	runtime->hw.channels_max = 0;
991 	runtime->hw.rates = 0;
992 	ptmin = UINT_MAX;
993 	/* check min/max rates and channels */
994 	list_for_each_entry(fp, &subs->fmt_list, list) {
995 		runtime->hw.rates |= fp->rates;
996 		if (runtime->hw.rate_min > fp->rate_min)
997 			runtime->hw.rate_min = fp->rate_min;
998 		if (runtime->hw.rate_max < fp->rate_max)
999 			runtime->hw.rate_max = fp->rate_max;
1000 		if (runtime->hw.channels_min > fp->channels)
1001 			runtime->hw.channels_min = fp->channels;
1002 		if (runtime->hw.channels_max < fp->channels)
1003 			runtime->hw.channels_max = fp->channels;
1004 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1005 			/* FIXME: there might be more than one audio formats... */
1006 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1007 				fp->frame_size;
1008 		}
1009 		pt = 125 * (1 << fp->datainterval);
1010 		ptmin = min(ptmin, pt);
1011 	}
1012 
1013 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1014 	if (subs->speed == USB_SPEED_FULL)
1015 		/* full speed devices have fixed data packet interval */
1016 		ptmin = 1000;
1017 	if (ptmin == 1000)
1018 		/* if period time doesn't go below 1 ms, no rules needed */
1019 		param_period_time_if_needed = -1;
1020 
1021 	err = snd_pcm_hw_constraint_minmax(runtime,
1022 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1023 					   ptmin, UINT_MAX);
1024 	if (err < 0)
1025 		return err;
1026 
1027 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1028 				  hw_rule_rate, subs,
1029 				  SNDRV_PCM_HW_PARAM_RATE,
1030 				  SNDRV_PCM_HW_PARAM_FORMAT,
1031 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1032 				  param_period_time_if_needed,
1033 				  -1);
1034 	if (err < 0)
1035 		return err;
1036 
1037 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1038 				  hw_rule_channels, subs,
1039 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1040 				  SNDRV_PCM_HW_PARAM_FORMAT,
1041 				  SNDRV_PCM_HW_PARAM_RATE,
1042 				  param_period_time_if_needed,
1043 				  -1);
1044 	if (err < 0)
1045 		return err;
1046 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1047 				  hw_rule_format, subs,
1048 				  SNDRV_PCM_HW_PARAM_FORMAT,
1049 				  SNDRV_PCM_HW_PARAM_RATE,
1050 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1051 				  param_period_time_if_needed,
1052 				  -1);
1053 	if (err < 0)
1054 		return err;
1055 	if (param_period_time_if_needed >= 0) {
1056 		err = snd_pcm_hw_rule_add(runtime, 0,
1057 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1058 					  hw_rule_period_time, subs,
1059 					  SNDRV_PCM_HW_PARAM_FORMAT,
1060 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1061 					  SNDRV_PCM_HW_PARAM_RATE,
1062 					  -1);
1063 		if (err < 0)
1064 			return err;
1065 	}
1066 
1067 	/* set max period and buffer sizes for 1 and 2 seconds, respectively */
1068 	err = snd_pcm_hw_constraint_minmax(runtime,
1069 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1070 					   0, 1000000);
1071 	if (err < 0)
1072 		return err;
1073 	err = snd_pcm_hw_constraint_minmax(runtime,
1074 					   SNDRV_PCM_HW_PARAM_BUFFER_TIME,
1075 					   0, 2000000);
1076 	if (err < 0)
1077 		return err;
1078 
1079 	/* additional hw constraints for implicit fb */
1080 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1081 				  hw_rule_format_implicit_fb, subs,
1082 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1083 	if (err < 0)
1084 		return err;
1085 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1086 				  hw_rule_rate_implicit_fb, subs,
1087 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1088 	if (err < 0)
1089 		return err;
1090 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1091 				  hw_rule_period_size_implicit_fb, subs,
1092 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1093 	if (err < 0)
1094 		return err;
1095 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1096 				  hw_rule_periods_implicit_fb, subs,
1097 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1098 	if (err < 0)
1099 		return err;
1100 
1101 	list_for_each_entry(fp, &subs->fmt_list, list) {
1102 		if (fp->implicit_fb) {
1103 			runtime->hw.info |= SNDRV_PCM_INFO_JOINT_DUPLEX;
1104 			break;
1105 		}
1106 	}
1107 
1108 	return 0;
1109 }
1110 
1111 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1112 {
1113 	int direction = substream->stream;
1114 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1115 	struct snd_pcm_runtime *runtime = substream->runtime;
1116 	struct snd_usb_substream *subs = &as->substream[direction];
1117 	int ret;
1118 
1119 	runtime->hw = snd_usb_hardware;
1120 	/* need an explicit sync to catch applptr update in low-latency mode */
1121 	if (direction == SNDRV_PCM_STREAM_PLAYBACK &&
1122 	    as->chip->lowlatency)
1123 		runtime->hw.info |= SNDRV_PCM_INFO_SYNC_APPLPTR;
1124 	runtime->private_data = subs;
1125 	subs->pcm_substream = substream;
1126 	/* runtime PM is also done there */
1127 
1128 	/* initialize DSD/DOP context */
1129 	subs->dsd_dop.byte_idx = 0;
1130 	subs->dsd_dop.channel = 0;
1131 	subs->dsd_dop.marker = 1;
1132 
1133 	ret = setup_hw_info(runtime, subs);
1134 	if (ret < 0)
1135 		return ret;
1136 	ret = snd_usb_autoresume(subs->stream->chip);
1137 	if (ret < 0)
1138 		return ret;
1139 	ret = snd_media_stream_init(subs, as->pcm, direction);
1140 	if (ret < 0)
1141 		snd_usb_autosuspend(subs->stream->chip);
1142 	return ret;
1143 }
1144 
1145 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1146 {
1147 	int direction = substream->stream;
1148 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1149 	struct snd_usb_substream *subs = &as->substream[direction];
1150 	int ret;
1151 
1152 	snd_media_stop_pipeline(subs);
1153 
1154 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1155 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1156 		snd_usb_unlock_shutdown(subs->stream->chip);
1157 		if (ret < 0)
1158 			return ret;
1159 	}
1160 
1161 	subs->pcm_substream = NULL;
1162 	snd_usb_autosuspend(subs->stream->chip);
1163 
1164 	return 0;
1165 }
1166 
1167 /* Since a URB can handle only a single linear buffer, we must use double
1168  * buffering when the data to be transferred overflows the buffer boundary.
1169  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1170  * for all URBs.
1171  */
1172 static void retire_capture_urb(struct snd_usb_substream *subs,
1173 			       struct urb *urb)
1174 {
1175 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1176 	unsigned int stride, frames, bytes, oldptr;
1177 	int i, period_elapsed = 0;
1178 	unsigned long flags;
1179 	unsigned char *cp;
1180 	int current_frame_number;
1181 
1182 	/* read frame number here, update pointer in critical section */
1183 	current_frame_number = usb_get_current_frame_number(subs->dev);
1184 
1185 	stride = runtime->frame_bits >> 3;
1186 
1187 	for (i = 0; i < urb->number_of_packets; i++) {
1188 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1189 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1190 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1191 				i, urb->iso_frame_desc[i].status);
1192 			// continue;
1193 		}
1194 		bytes = urb->iso_frame_desc[i].actual_length;
1195 		if (subs->stream_offset_adj > 0) {
1196 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1197 			cp += adj;
1198 			bytes -= adj;
1199 			subs->stream_offset_adj -= adj;
1200 		}
1201 		frames = bytes / stride;
1202 		if (!subs->txfr_quirk)
1203 			bytes = frames * stride;
1204 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1205 			int oldbytes = bytes;
1206 			bytes = frames * stride;
1207 			dev_warn_ratelimited(&subs->dev->dev,
1208 				 "Corrected urb data len. %d->%d\n",
1209 							oldbytes, bytes);
1210 		}
1211 		/* update the current pointer */
1212 		spin_lock_irqsave(&subs->lock, flags);
1213 		oldptr = subs->hwptr_done;
1214 		subs->hwptr_done += bytes;
1215 		if (subs->hwptr_done >= subs->buffer_bytes)
1216 			subs->hwptr_done -= subs->buffer_bytes;
1217 		frames = (bytes + (oldptr % stride)) / stride;
1218 		subs->transfer_done += frames;
1219 		if (subs->transfer_done >= runtime->period_size) {
1220 			subs->transfer_done -= runtime->period_size;
1221 			period_elapsed = 1;
1222 		}
1223 
1224 		/* realign last_frame_number */
1225 		subs->last_frame_number = current_frame_number;
1226 
1227 		spin_unlock_irqrestore(&subs->lock, flags);
1228 		/* copy a data chunk */
1229 		if (oldptr + bytes > subs->buffer_bytes) {
1230 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1231 
1232 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1233 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1234 		} else {
1235 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1236 		}
1237 	}
1238 
1239 	if (period_elapsed)
1240 		snd_pcm_period_elapsed(subs->pcm_substream);
1241 }
1242 
1243 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1244 				  struct urb *urb, unsigned int bytes)
1245 {
1246 	struct snd_urb_ctx *ctx = urb->context;
1247 
1248 	ctx->queued += bytes;
1249 	subs->inflight_bytes += bytes;
1250 	subs->hwptr_done += bytes;
1251 	if (subs->hwptr_done >= subs->buffer_bytes)
1252 		subs->hwptr_done -= subs->buffer_bytes;
1253 }
1254 
1255 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1256 					     struct urb *urb, unsigned int bytes)
1257 {
1258 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1259 	unsigned int dst_idx = 0;
1260 	unsigned int src_idx = subs->hwptr_done;
1261 	unsigned int wrap = subs->buffer_bytes;
1262 	u8 *dst = urb->transfer_buffer;
1263 	u8 *src = runtime->dma_area;
1264 	u8 marker[] = { 0x05, 0xfa };
1265 	unsigned int queued = 0;
1266 
1267 	/*
1268 	 * The DSP DOP format defines a way to transport DSD samples over
1269 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1270 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1271 	 * 2 additional bytes of actual payload. The whole frame is stored
1272 	 * LSB.
1273 	 *
1274 	 * Hence, for a stereo transport, the buffer layout looks like this,
1275 	 * where L refers to left channel samples and R to right.
1276 	 *
1277 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1278 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1279 	 *   .....
1280 	 *
1281 	 */
1282 
1283 	while (bytes--) {
1284 		if (++subs->dsd_dop.byte_idx == 3) {
1285 			/* frame boundary? */
1286 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1287 			src_idx += 2;
1288 			subs->dsd_dop.byte_idx = 0;
1289 
1290 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1291 				/* alternate the marker */
1292 				subs->dsd_dop.marker++;
1293 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1294 				subs->dsd_dop.channel = 0;
1295 			}
1296 		} else {
1297 			/* stuff the DSD payload */
1298 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1299 
1300 			if (subs->cur_audiofmt->dsd_bitrev)
1301 				dst[dst_idx++] = bitrev8(src[idx]);
1302 			else
1303 				dst[dst_idx++] = src[idx];
1304 			queued++;
1305 		}
1306 	}
1307 
1308 	urb_ctx_queue_advance(subs, urb, queued);
1309 }
1310 
1311 /* copy bit-reversed bytes onto transfer buffer */
1312 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1313 					 struct urb *urb, unsigned int bytes)
1314 {
1315 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1316 	const u8 *src = runtime->dma_area;
1317 	u8 *buf = urb->transfer_buffer;
1318 	int i, ofs = subs->hwptr_done;
1319 
1320 	for (i = 0; i < bytes; i++) {
1321 		*buf++ = bitrev8(src[ofs]);
1322 		if (++ofs >= subs->buffer_bytes)
1323 			ofs = 0;
1324 	}
1325 
1326 	urb_ctx_queue_advance(subs, urb, bytes);
1327 }
1328 
1329 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1330 			int offset, int stride, unsigned int bytes)
1331 {
1332 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1333 
1334 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1335 		/* err, the transferred area goes over buffer boundary. */
1336 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1337 
1338 		memcpy(urb->transfer_buffer + offset,
1339 		       runtime->dma_area + subs->hwptr_done, bytes1);
1340 		memcpy(urb->transfer_buffer + offset + bytes1,
1341 		       runtime->dma_area, bytes - bytes1);
1342 	} else {
1343 		memcpy(urb->transfer_buffer + offset,
1344 		       runtime->dma_area + subs->hwptr_done, bytes);
1345 	}
1346 
1347 	urb_ctx_queue_advance(subs, urb, bytes);
1348 }
1349 
1350 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1351 				      struct urb *urb, int stride,
1352 				      unsigned int bytes)
1353 {
1354 	__le32 packet_length;
1355 	int i;
1356 
1357 	/* Put __le32 length descriptor at start of each packet. */
1358 	for (i = 0; i < urb->number_of_packets; i++) {
1359 		unsigned int length = urb->iso_frame_desc[i].length;
1360 		unsigned int offset = urb->iso_frame_desc[i].offset;
1361 
1362 		packet_length = cpu_to_le32(length);
1363 		offset += i * sizeof(packet_length);
1364 		urb->iso_frame_desc[i].offset = offset;
1365 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1366 		memcpy(urb->transfer_buffer + offset,
1367 		       &packet_length, sizeof(packet_length));
1368 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1369 			    stride, length);
1370 	}
1371 	/* Adjust transfer size accordingly. */
1372 	bytes += urb->number_of_packets * sizeof(packet_length);
1373 	return bytes;
1374 }
1375 
1376 static int prepare_playback_urb(struct snd_usb_substream *subs,
1377 				struct urb *urb,
1378 				bool in_stream_lock)
1379 {
1380 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1381 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1382 	struct snd_urb_ctx *ctx = urb->context;
1383 	unsigned int frames, bytes;
1384 	int counts;
1385 	unsigned int transfer_done, frame_limit, avail = 0;
1386 	int i, stride, period_elapsed = 0;
1387 	unsigned long flags;
1388 	int err = 0;
1389 
1390 	stride = ep->stride;
1391 
1392 	frames = 0;
1393 	ctx->queued = 0;
1394 	urb->number_of_packets = 0;
1395 
1396 	spin_lock_irqsave(&subs->lock, flags);
1397 	frame_limit = subs->frame_limit + ep->max_urb_frames;
1398 	transfer_done = subs->transfer_done;
1399 
1400 	if (subs->lowlatency_playback &&
1401 	    runtime->status->state != SNDRV_PCM_STATE_DRAINING) {
1402 		unsigned int hwptr = subs->hwptr_done / stride;
1403 
1404 		/* calculate the byte offset-in-buffer of the appl_ptr */
1405 		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
1406 			% runtime->buffer_size;
1407 		if (avail <= hwptr)
1408 			avail += runtime->buffer_size;
1409 		avail -= hwptr;
1410 	}
1411 
1412 	for (i = 0; i < ctx->packets; i++) {
1413 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
1414 		if (counts < 0)
1415 			break;
1416 		/* set up descriptor */
1417 		urb->iso_frame_desc[i].offset = frames * stride;
1418 		urb->iso_frame_desc[i].length = counts * stride;
1419 		frames += counts;
1420 		avail -= counts;
1421 		urb->number_of_packets++;
1422 		transfer_done += counts;
1423 		if (transfer_done >= runtime->period_size) {
1424 			transfer_done -= runtime->period_size;
1425 			frame_limit = 0;
1426 			period_elapsed = 1;
1427 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1428 				if (transfer_done > 0) {
1429 					/* FIXME: fill-max mode is not
1430 					 * supported yet */
1431 					frames -= transfer_done;
1432 					counts -= transfer_done;
1433 					urb->iso_frame_desc[i].length =
1434 						counts * stride;
1435 					transfer_done = 0;
1436 				}
1437 				i++;
1438 				if (i < ctx->packets) {
1439 					/* add a transfer delimiter */
1440 					urb->iso_frame_desc[i].offset =
1441 						frames * stride;
1442 					urb->iso_frame_desc[i].length = 0;
1443 					urb->number_of_packets++;
1444 				}
1445 				break;
1446 			}
1447 		}
1448 		/* finish at the period boundary or after enough frames */
1449 		if ((period_elapsed || transfer_done >= frame_limit) &&
1450 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1451 			break;
1452 	}
1453 
1454 	if (!frames) {
1455 		err = -EAGAIN;
1456 		goto unlock;
1457 	}
1458 
1459 	bytes = frames * stride;
1460 	subs->transfer_done = transfer_done;
1461 	subs->frame_limit = frame_limit;
1462 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1463 		     subs->cur_audiofmt->dsd_dop)) {
1464 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1465 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1466 			   subs->cur_audiofmt->dsd_bitrev)) {
1467 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1468 	} else {
1469 		/* usual PCM */
1470 		if (!subs->tx_length_quirk)
1471 			copy_to_urb(subs, urb, 0, stride, bytes);
1472 		else
1473 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1474 			/* bytes is now amount of outgoing data */
1475 	}
1476 
1477 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1478 
1479 	if (subs->trigger_tstamp_pending_update) {
1480 		/* this is the first actual URB submitted,
1481 		 * update trigger timestamp to reflect actual start time
1482 		 */
1483 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1484 		subs->trigger_tstamp_pending_update = false;
1485 	}
1486 
1487 	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
1488 		subs->period_elapsed_pending = 1;
1489 		period_elapsed = 0;
1490 	}
1491 
1492  unlock:
1493 	spin_unlock_irqrestore(&subs->lock, flags);
1494 	if (err < 0)
1495 		return err;
1496 	urb->transfer_buffer_length = bytes;
1497 	if (period_elapsed) {
1498 		if (in_stream_lock)
1499 			snd_pcm_period_elapsed_under_stream_lock(subs->pcm_substream);
1500 		else
1501 			snd_pcm_period_elapsed(subs->pcm_substream);
1502 	}
1503 	return 0;
1504 }
1505 
1506 /*
1507  * process after playback data complete
1508  * - decrease the delay count again
1509  */
1510 static void retire_playback_urb(struct snd_usb_substream *subs,
1511 			       struct urb *urb)
1512 {
1513 	unsigned long flags;
1514 	struct snd_urb_ctx *ctx = urb->context;
1515 	bool period_elapsed = false;
1516 
1517 	spin_lock_irqsave(&subs->lock, flags);
1518 	if (ctx->queued) {
1519 		if (subs->inflight_bytes >= ctx->queued)
1520 			subs->inflight_bytes -= ctx->queued;
1521 		else
1522 			subs->inflight_bytes = 0;
1523 	}
1524 
1525 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1526 	if (subs->running) {
1527 		period_elapsed = subs->period_elapsed_pending;
1528 		subs->period_elapsed_pending = 0;
1529 	}
1530 	spin_unlock_irqrestore(&subs->lock, flags);
1531 	if (period_elapsed)
1532 		snd_pcm_period_elapsed(subs->pcm_substream);
1533 }
1534 
1535 /* PCM ack callback for the playback stream;
1536  * this plays a role only when the stream is running in low-latency mode.
1537  */
1538 static int snd_usb_pcm_playback_ack(struct snd_pcm_substream *substream)
1539 {
1540 	struct snd_usb_substream *subs = substream->runtime->private_data;
1541 	struct snd_usb_endpoint *ep;
1542 
1543 	if (!subs->lowlatency_playback || !subs->running)
1544 		return 0;
1545 	ep = subs->data_endpoint;
1546 	if (!ep)
1547 		return 0;
1548 	/* When no more in-flight URBs available, try to process the pending
1549 	 * outputs here
1550 	 */
1551 	if (!ep->active_mask)
1552 		snd_usb_queue_pending_output_urbs(ep, true);
1553 	return 0;
1554 }
1555 
1556 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1557 					      int cmd)
1558 {
1559 	struct snd_usb_substream *subs = substream->runtime->private_data;
1560 	int err;
1561 
1562 	switch (cmd) {
1563 	case SNDRV_PCM_TRIGGER_START:
1564 		subs->trigger_tstamp_pending_update = true;
1565 		fallthrough;
1566 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1567 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1568 					      prepare_playback_urb,
1569 					      retire_playback_urb,
1570 					      subs);
1571 		if (subs->lowlatency_playback &&
1572 		    cmd == SNDRV_PCM_TRIGGER_START) {
1573 			if (in_free_wheeling_mode(substream->runtime))
1574 				subs->lowlatency_playback = false;
1575 			err = start_endpoints(subs);
1576 			if (err < 0) {
1577 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1578 							      NULL, NULL, NULL);
1579 				return err;
1580 			}
1581 		}
1582 		subs->running = 1;
1583 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1584 			subs->cur_audiofmt->iface,
1585 			subs->cur_audiofmt->altsetting);
1586 		return 0;
1587 	case SNDRV_PCM_TRIGGER_SUSPEND:
1588 	case SNDRV_PCM_TRIGGER_STOP:
1589 		stop_endpoints(subs, substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING);
1590 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1591 					      NULL, NULL, NULL);
1592 		subs->running = 0;
1593 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1594 			subs->cur_audiofmt->iface,
1595 			subs->cur_audiofmt->altsetting);
1596 		return 0;
1597 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1598 		/* keep retire_data_urb for delay calculation */
1599 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1600 					      NULL,
1601 					      retire_playback_urb,
1602 					      subs);
1603 		subs->running = 0;
1604 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1605 			subs->cur_audiofmt->iface,
1606 			subs->cur_audiofmt->altsetting);
1607 		return 0;
1608 	}
1609 
1610 	return -EINVAL;
1611 }
1612 
1613 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1614 					     int cmd)
1615 {
1616 	int err;
1617 	struct snd_usb_substream *subs = substream->runtime->private_data;
1618 
1619 	switch (cmd) {
1620 	case SNDRV_PCM_TRIGGER_START:
1621 		err = start_endpoints(subs);
1622 		if (err < 0)
1623 			return err;
1624 		fallthrough;
1625 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1626 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1627 					      NULL, retire_capture_urb,
1628 					      subs);
1629 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1630 		subs->running = 1;
1631 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1632 			subs->cur_audiofmt->iface,
1633 			subs->cur_audiofmt->altsetting);
1634 		return 0;
1635 	case SNDRV_PCM_TRIGGER_SUSPEND:
1636 	case SNDRV_PCM_TRIGGER_STOP:
1637 		stop_endpoints(subs, false);
1638 		fallthrough;
1639 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1640 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1641 					      NULL, NULL, NULL);
1642 		subs->running = 0;
1643 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1644 			subs->cur_audiofmt->iface,
1645 			subs->cur_audiofmt->altsetting);
1646 		return 0;
1647 	}
1648 
1649 	return -EINVAL;
1650 }
1651 
1652 static const struct snd_pcm_ops snd_usb_playback_ops = {
1653 	.open =		snd_usb_pcm_open,
1654 	.close =	snd_usb_pcm_close,
1655 	.hw_params =	snd_usb_hw_params,
1656 	.hw_free =	snd_usb_hw_free,
1657 	.prepare =	snd_usb_pcm_prepare,
1658 	.trigger =	snd_usb_substream_playback_trigger,
1659 	.sync_stop =	snd_usb_pcm_sync_stop,
1660 	.pointer =	snd_usb_pcm_pointer,
1661 	.ack =		snd_usb_pcm_playback_ack,
1662 };
1663 
1664 static const struct snd_pcm_ops snd_usb_capture_ops = {
1665 	.open =		snd_usb_pcm_open,
1666 	.close =	snd_usb_pcm_close,
1667 	.hw_params =	snd_usb_hw_params,
1668 	.hw_free =	snd_usb_hw_free,
1669 	.prepare =	snd_usb_pcm_prepare,
1670 	.trigger =	snd_usb_substream_capture_trigger,
1671 	.sync_stop =	snd_usb_pcm_sync_stop,
1672 	.pointer =	snd_usb_pcm_pointer,
1673 };
1674 
1675 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1676 {
1677 	const struct snd_pcm_ops *ops;
1678 
1679 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1680 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1681 	snd_pcm_set_ops(pcm, stream, ops);
1682 }
1683 
1684 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1685 {
1686 	struct snd_pcm *pcm = subs->stream->pcm;
1687 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1688 	struct device *dev = subs->dev->bus->sysdev;
1689 
1690 	if (snd_usb_use_vmalloc)
1691 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1692 					   NULL, 0, 0);
1693 	else
1694 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1695 					   dev, 64*1024, 512*1024);
1696 }
1697