xref: /openbmc/linux/sound/usb/pcm.c (revision be471fe3)
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)
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);
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);
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);
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))
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))
576 			sync_pending_stops(subs);
577 		close_endpoints(chip, subs);
578 		snd_usb_unlock_shutdown(chip);
579 	}
580 
581 	return 0;
582 }
583 
584 /*
585  * prepare callback
586  *
587  * only a few subtle things...
588  */
589 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
590 {
591 	struct snd_pcm_runtime *runtime = substream->runtime;
592 	struct snd_usb_substream *subs = runtime->private_data;
593 	struct snd_usb_audio *chip = subs->stream->chip;
594 	int ret;
595 
596 	ret = snd_usb_lock_shutdown(chip);
597 	if (ret < 0)
598 		return ret;
599 	if (snd_BUG_ON(!subs->data_endpoint)) {
600 		ret = -EIO;
601 		goto unlock;
602 	}
603 
604 	ret = configure_endpoints(chip, subs);
605 	if (ret < 0)
606 		goto unlock;
607 
608 	/* reset the pointer */
609 	subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
610 	subs->inflight_bytes = 0;
611 	subs->hwptr_done = 0;
612 	subs->transfer_done = 0;
613 	subs->last_frame_number = 0;
614 	runtime->delay = 0;
615 
616  unlock:
617 	snd_usb_unlock_shutdown(chip);
618 	return ret;
619 }
620 
621 /*
622  * h/w constraints
623  */
624 
625 #ifdef HW_CONST_DEBUG
626 #define hwc_debug(fmt, args...) pr_debug(fmt, ##args)
627 #else
628 #define hwc_debug(fmt, args...) do { } while(0)
629 #endif
630 
631 static const struct snd_pcm_hardware snd_usb_hardware =
632 {
633 	.info =			SNDRV_PCM_INFO_MMAP |
634 				SNDRV_PCM_INFO_MMAP_VALID |
635 				SNDRV_PCM_INFO_BATCH |
636 				SNDRV_PCM_INFO_INTERLEAVED |
637 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
638 				SNDRV_PCM_INFO_PAUSE,
639 	.channels_min =		1,
640 	.channels_max =		256,
641 	.buffer_bytes_max =	1024 * 1024,
642 	.period_bytes_min =	64,
643 	.period_bytes_max =	512 * 1024,
644 	.periods_min =		2,
645 	.periods_max =		1024,
646 };
647 
648 static int hw_check_valid_format(struct snd_usb_substream *subs,
649 				 struct snd_pcm_hw_params *params,
650 				 const struct audioformat *fp)
651 {
652 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
653 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
654 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
655 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
656 	struct snd_mask check_fmts;
657 	unsigned int ptime;
658 
659 	/* check the format */
660 	snd_mask_none(&check_fmts);
661 	check_fmts.bits[0] = (u32)fp->formats;
662 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
663 	snd_mask_intersect(&check_fmts, fmts);
664 	if (snd_mask_empty(&check_fmts)) {
665 		hwc_debug("   > check: no supported format 0x%llx\n", fp->formats);
666 		return 0;
667 	}
668 	/* check the channels */
669 	if (fp->channels < ct->min || fp->channels > ct->max) {
670 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
671 		return 0;
672 	}
673 	/* check the rate is within the range */
674 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
675 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
676 		return 0;
677 	}
678 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
679 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
680 		return 0;
681 	}
682 	/* check whether the period time is >= the data packet interval */
683 	if (subs->speed != USB_SPEED_FULL) {
684 		ptime = 125 * (1 << fp->datainterval);
685 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
686 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
687 			return 0;
688 		}
689 	}
690 	return 1;
691 }
692 
693 static int apply_hw_params_minmax(struct snd_interval *it, unsigned int rmin,
694 				  unsigned int rmax)
695 {
696 	int changed;
697 
698 	if (rmin > rmax) {
699 		hwc_debug("  --> get empty\n");
700 		it->empty = 1;
701 		return -EINVAL;
702 	}
703 
704 	changed = 0;
705 	if (it->min < rmin) {
706 		it->min = rmin;
707 		it->openmin = 0;
708 		changed = 1;
709 	}
710 	if (it->max > rmax) {
711 		it->max = rmax;
712 		it->openmax = 0;
713 		changed = 1;
714 	}
715 	if (snd_interval_checkempty(it)) {
716 		it->empty = 1;
717 		return -EINVAL;
718 	}
719 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
720 	return changed;
721 }
722 
723 static int hw_rule_rate(struct snd_pcm_hw_params *params,
724 			struct snd_pcm_hw_rule *rule)
725 {
726 	struct snd_usb_substream *subs = rule->private;
727 	const struct audioformat *fp;
728 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
729 	unsigned int rmin, rmax, r;
730 	int i;
731 
732 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
733 	rmin = UINT_MAX;
734 	rmax = 0;
735 	list_for_each_entry(fp, &subs->fmt_list, list) {
736 		if (!hw_check_valid_format(subs, params, fp))
737 			continue;
738 		if (fp->rate_table && fp->nr_rates) {
739 			for (i = 0; i < fp->nr_rates; i++) {
740 				r = fp->rate_table[i];
741 				if (!snd_interval_test(it, r))
742 					continue;
743 				rmin = min(rmin, r);
744 				rmax = max(rmax, r);
745 			}
746 		} else {
747 			rmin = min(rmin, fp->rate_min);
748 			rmax = max(rmax, fp->rate_max);
749 		}
750 	}
751 
752 	return apply_hw_params_minmax(it, rmin, rmax);
753 }
754 
755 
756 static int hw_rule_channels(struct snd_pcm_hw_params *params,
757 			    struct snd_pcm_hw_rule *rule)
758 {
759 	struct snd_usb_substream *subs = rule->private;
760 	const struct audioformat *fp;
761 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
762 	unsigned int rmin, rmax;
763 
764 	hwc_debug("hw_rule_channels: (%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 		rmin = min(rmin, fp->channels);
771 		rmax = max(rmax, fp->channels);
772 	}
773 
774 	return apply_hw_params_minmax(it, rmin, rmax);
775 }
776 
777 static int apply_hw_params_format_bits(struct snd_mask *fmt, u64 fbits)
778 {
779 	u32 oldbits[2];
780 	int changed;
781 
782 	oldbits[0] = fmt->bits[0];
783 	oldbits[1] = fmt->bits[1];
784 	fmt->bits[0] &= (u32)fbits;
785 	fmt->bits[1] &= (u32)(fbits >> 32);
786 	if (!fmt->bits[0] && !fmt->bits[1]) {
787 		hwc_debug("  --> get empty\n");
788 		return -EINVAL;
789 	}
790 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
791 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
792 	return changed;
793 }
794 
795 static int hw_rule_format(struct snd_pcm_hw_params *params,
796 			  struct snd_pcm_hw_rule *rule)
797 {
798 	struct snd_usb_substream *subs = rule->private;
799 	const struct audioformat *fp;
800 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
801 	u64 fbits;
802 
803 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
804 	fbits = 0;
805 	list_for_each_entry(fp, &subs->fmt_list, list) {
806 		if (!hw_check_valid_format(subs, params, fp))
807 			continue;
808 		fbits |= fp->formats;
809 	}
810 	return apply_hw_params_format_bits(fmt, fbits);
811 }
812 
813 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
814 			       struct snd_pcm_hw_rule *rule)
815 {
816 	struct snd_usb_substream *subs = rule->private;
817 	const struct audioformat *fp;
818 	struct snd_interval *it;
819 	unsigned char min_datainterval;
820 	unsigned int pmin;
821 
822 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
823 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
824 	min_datainterval = 0xff;
825 	list_for_each_entry(fp, &subs->fmt_list, list) {
826 		if (!hw_check_valid_format(subs, params, fp))
827 			continue;
828 		min_datainterval = min(min_datainterval, fp->datainterval);
829 	}
830 	if (min_datainterval == 0xff) {
831 		hwc_debug("  --> get empty\n");
832 		it->empty = 1;
833 		return -EINVAL;
834 	}
835 	pmin = 125 * (1 << min_datainterval);
836 
837 	return apply_hw_params_minmax(it, pmin, UINT_MAX);
838 }
839 
840 /* get the EP or the sync EP for implicit fb when it's already set up */
841 static const struct snd_usb_endpoint *
842 get_sync_ep_from_substream(struct snd_usb_substream *subs)
843 {
844 	struct snd_usb_audio *chip = subs->stream->chip;
845 	const struct audioformat *fp;
846 	const struct snd_usb_endpoint *ep;
847 
848 	list_for_each_entry(fp, &subs->fmt_list, list) {
849 		ep = snd_usb_get_endpoint(chip, fp->endpoint);
850 		if (ep && ep->cur_audiofmt) {
851 			/* if EP is already opened solely for this substream,
852 			 * we still allow us to change the parameter; otherwise
853 			 * this substream has to follow the existing parameter
854 			 */
855 			if (ep->cur_audiofmt != subs->cur_audiofmt || ep->opened > 1)
856 				return ep;
857 		}
858 		if (!fp->implicit_fb)
859 			continue;
860 		/* for the implicit fb, check the sync ep as well */
861 		ep = snd_usb_get_endpoint(chip, fp->sync_ep);
862 		if (ep && ep->cur_audiofmt)
863 			return ep;
864 	}
865 	return NULL;
866 }
867 
868 /* additional hw constraints for implicit feedback mode */
869 static int hw_rule_format_implicit_fb(struct snd_pcm_hw_params *params,
870 				      struct snd_pcm_hw_rule *rule)
871 {
872 	struct snd_usb_substream *subs = rule->private;
873 	const struct snd_usb_endpoint *ep;
874 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
875 
876 	ep = get_sync_ep_from_substream(subs);
877 	if (!ep)
878 		return 0;
879 
880 	hwc_debug("applying %s\n", __func__);
881 	return apply_hw_params_format_bits(fmt, pcm_format_to_bits(ep->cur_format));
882 }
883 
884 static int hw_rule_rate_implicit_fb(struct snd_pcm_hw_params *params,
885 				    struct snd_pcm_hw_rule *rule)
886 {
887 	struct snd_usb_substream *subs = rule->private;
888 	const struct snd_usb_endpoint *ep;
889 	struct snd_interval *it;
890 
891 	ep = get_sync_ep_from_substream(subs);
892 	if (!ep)
893 		return 0;
894 
895 	hwc_debug("applying %s\n", __func__);
896 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
897 	return apply_hw_params_minmax(it, ep->cur_rate, ep->cur_rate);
898 }
899 
900 static int hw_rule_period_size_implicit_fb(struct snd_pcm_hw_params *params,
901 					   struct snd_pcm_hw_rule *rule)
902 {
903 	struct snd_usb_substream *subs = rule->private;
904 	const struct snd_usb_endpoint *ep;
905 	struct snd_interval *it;
906 
907 	ep = get_sync_ep_from_substream(subs);
908 	if (!ep)
909 		return 0;
910 
911 	hwc_debug("applying %s\n", __func__);
912 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
913 	return apply_hw_params_minmax(it, ep->cur_period_frames,
914 				      ep->cur_period_frames);
915 }
916 
917 static int hw_rule_periods_implicit_fb(struct snd_pcm_hw_params *params,
918 				       struct snd_pcm_hw_rule *rule)
919 {
920 	struct snd_usb_substream *subs = rule->private;
921 	const struct snd_usb_endpoint *ep;
922 	struct snd_interval *it;
923 
924 	ep = get_sync_ep_from_substream(subs);
925 	if (!ep)
926 		return 0;
927 
928 	hwc_debug("applying %s\n", __func__);
929 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIODS);
930 	return apply_hw_params_minmax(it, ep->cur_buffer_periods,
931 				      ep->cur_buffer_periods);
932 }
933 
934 /*
935  * set up the runtime hardware information.
936  */
937 
938 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
939 {
940 	const struct audioformat *fp;
941 	unsigned int pt, ptmin;
942 	int param_period_time_if_needed = -1;
943 	int err;
944 
945 	runtime->hw.formats = subs->formats;
946 
947 	runtime->hw.rate_min = 0x7fffffff;
948 	runtime->hw.rate_max = 0;
949 	runtime->hw.channels_min = 256;
950 	runtime->hw.channels_max = 0;
951 	runtime->hw.rates = 0;
952 	ptmin = UINT_MAX;
953 	/* check min/max rates and channels */
954 	list_for_each_entry(fp, &subs->fmt_list, list) {
955 		runtime->hw.rates |= fp->rates;
956 		if (runtime->hw.rate_min > fp->rate_min)
957 			runtime->hw.rate_min = fp->rate_min;
958 		if (runtime->hw.rate_max < fp->rate_max)
959 			runtime->hw.rate_max = fp->rate_max;
960 		if (runtime->hw.channels_min > fp->channels)
961 			runtime->hw.channels_min = fp->channels;
962 		if (runtime->hw.channels_max < fp->channels)
963 			runtime->hw.channels_max = fp->channels;
964 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
965 			/* FIXME: there might be more than one audio formats... */
966 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
967 				fp->frame_size;
968 		}
969 		pt = 125 * (1 << fp->datainterval);
970 		ptmin = min(ptmin, pt);
971 	}
972 
973 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
974 	if (subs->speed == USB_SPEED_FULL)
975 		/* full speed devices have fixed data packet interval */
976 		ptmin = 1000;
977 	if (ptmin == 1000)
978 		/* if period time doesn't go below 1 ms, no rules needed */
979 		param_period_time_if_needed = -1;
980 
981 	err = snd_pcm_hw_constraint_minmax(runtime,
982 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
983 					   ptmin, UINT_MAX);
984 	if (err < 0)
985 		return err;
986 
987 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
988 				  hw_rule_rate, subs,
989 				  SNDRV_PCM_HW_PARAM_RATE,
990 				  SNDRV_PCM_HW_PARAM_FORMAT,
991 				  SNDRV_PCM_HW_PARAM_CHANNELS,
992 				  param_period_time_if_needed,
993 				  -1);
994 	if (err < 0)
995 		return err;
996 
997 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
998 				  hw_rule_channels, subs,
999 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1000 				  SNDRV_PCM_HW_PARAM_FORMAT,
1001 				  SNDRV_PCM_HW_PARAM_RATE,
1002 				  param_period_time_if_needed,
1003 				  -1);
1004 	if (err < 0)
1005 		return err;
1006 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1007 				  hw_rule_format, subs,
1008 				  SNDRV_PCM_HW_PARAM_FORMAT,
1009 				  SNDRV_PCM_HW_PARAM_RATE,
1010 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1011 				  param_period_time_if_needed,
1012 				  -1);
1013 	if (err < 0)
1014 		return err;
1015 	if (param_period_time_if_needed >= 0) {
1016 		err = snd_pcm_hw_rule_add(runtime, 0,
1017 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1018 					  hw_rule_period_time, subs,
1019 					  SNDRV_PCM_HW_PARAM_FORMAT,
1020 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1021 					  SNDRV_PCM_HW_PARAM_RATE,
1022 					  -1);
1023 		if (err < 0)
1024 			return err;
1025 	}
1026 
1027 	/* additional hw constraints for implicit fb */
1028 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1029 				  hw_rule_format_implicit_fb, subs,
1030 				  SNDRV_PCM_HW_PARAM_FORMAT, -1);
1031 	if (err < 0)
1032 		return err;
1033 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1034 				  hw_rule_rate_implicit_fb, subs,
1035 				  SNDRV_PCM_HW_PARAM_RATE, -1);
1036 	if (err < 0)
1037 		return err;
1038 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
1039 				  hw_rule_period_size_implicit_fb, subs,
1040 				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
1041 	if (err < 0)
1042 		return err;
1043 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS,
1044 				  hw_rule_periods_implicit_fb, subs,
1045 				  SNDRV_PCM_HW_PARAM_PERIODS, -1);
1046 	if (err < 0)
1047 		return err;
1048 
1049 	return 0;
1050 }
1051 
1052 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1053 {
1054 	int direction = substream->stream;
1055 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1056 	struct snd_pcm_runtime *runtime = substream->runtime;
1057 	struct snd_usb_substream *subs = &as->substream[direction];
1058 	int ret;
1059 
1060 	runtime->hw = snd_usb_hardware;
1061 	runtime->private_data = subs;
1062 	subs->pcm_substream = substream;
1063 	/* runtime PM is also done there */
1064 
1065 	/* initialize DSD/DOP context */
1066 	subs->dsd_dop.byte_idx = 0;
1067 	subs->dsd_dop.channel = 0;
1068 	subs->dsd_dop.marker = 1;
1069 
1070 	ret = setup_hw_info(runtime, subs);
1071 	if (ret < 0)
1072 		return ret;
1073 	ret = snd_usb_autoresume(subs->stream->chip);
1074 	if (ret < 0)
1075 		return ret;
1076 	ret = snd_media_stream_init(subs, as->pcm, direction);
1077 	if (ret < 0)
1078 		snd_usb_autosuspend(subs->stream->chip);
1079 	return ret;
1080 }
1081 
1082 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1083 {
1084 	int direction = substream->stream;
1085 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1086 	struct snd_usb_substream *subs = &as->substream[direction];
1087 	int ret;
1088 
1089 	snd_media_stop_pipeline(subs);
1090 
1091 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
1092 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1093 		snd_usb_unlock_shutdown(subs->stream->chip);
1094 		if (ret < 0)
1095 			return ret;
1096 	}
1097 
1098 	subs->pcm_substream = NULL;
1099 	snd_usb_autosuspend(subs->stream->chip);
1100 
1101 	return 0;
1102 }
1103 
1104 /* Since a URB can handle only a single linear buffer, we must use double
1105  * buffering when the data to be transferred overflows the buffer boundary.
1106  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1107  * for all URBs.
1108  */
1109 static void retire_capture_urb(struct snd_usb_substream *subs,
1110 			       struct urb *urb)
1111 {
1112 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1113 	unsigned int stride, frames, bytes, oldptr;
1114 	int i, period_elapsed = 0;
1115 	unsigned long flags;
1116 	unsigned char *cp;
1117 	int current_frame_number;
1118 
1119 	/* read frame number here, update pointer in critical section */
1120 	current_frame_number = usb_get_current_frame_number(subs->dev);
1121 
1122 	stride = runtime->frame_bits >> 3;
1123 
1124 	for (i = 0; i < urb->number_of_packets; i++) {
1125 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1126 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1127 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1128 				i, urb->iso_frame_desc[i].status);
1129 			// continue;
1130 		}
1131 		bytes = urb->iso_frame_desc[i].actual_length;
1132 		if (subs->stream_offset_adj > 0) {
1133 			unsigned int adj = min(subs->stream_offset_adj, bytes);
1134 			cp += adj;
1135 			bytes -= adj;
1136 			subs->stream_offset_adj -= adj;
1137 		}
1138 		frames = bytes / stride;
1139 		if (!subs->txfr_quirk)
1140 			bytes = frames * stride;
1141 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1142 			int oldbytes = bytes;
1143 			bytes = frames * stride;
1144 			dev_warn_ratelimited(&subs->dev->dev,
1145 				 "Corrected urb data len. %d->%d\n",
1146 							oldbytes, bytes);
1147 		}
1148 		/* update the current pointer */
1149 		spin_lock_irqsave(&subs->lock, flags);
1150 		oldptr = subs->hwptr_done;
1151 		subs->hwptr_done += bytes;
1152 		if (subs->hwptr_done >= subs->buffer_bytes)
1153 			subs->hwptr_done -= subs->buffer_bytes;
1154 		frames = (bytes + (oldptr % stride)) / stride;
1155 		subs->transfer_done += frames;
1156 		if (subs->transfer_done >= runtime->period_size) {
1157 			subs->transfer_done -= runtime->period_size;
1158 			period_elapsed = 1;
1159 		}
1160 
1161 		/* realign last_frame_number */
1162 		subs->last_frame_number = current_frame_number;
1163 
1164 		spin_unlock_irqrestore(&subs->lock, flags);
1165 		/* copy a data chunk */
1166 		if (oldptr + bytes > subs->buffer_bytes) {
1167 			unsigned int bytes1 = subs->buffer_bytes - oldptr;
1168 
1169 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1170 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1171 		} else {
1172 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1173 		}
1174 	}
1175 
1176 	if (period_elapsed)
1177 		snd_pcm_period_elapsed(subs->pcm_substream);
1178 }
1179 
1180 static void urb_ctx_queue_advance(struct snd_usb_substream *subs,
1181 				  struct urb *urb, unsigned int bytes)
1182 {
1183 	struct snd_urb_ctx *ctx = urb->context;
1184 
1185 	ctx->queued += bytes;
1186 	subs->inflight_bytes += bytes;
1187 	subs->hwptr_done += bytes;
1188 	if (subs->hwptr_done >= subs->buffer_bytes)
1189 		subs->hwptr_done -= subs->buffer_bytes;
1190 }
1191 
1192 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1193 					     struct urb *urb, unsigned int bytes)
1194 {
1195 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1196 	unsigned int dst_idx = 0;
1197 	unsigned int src_idx = subs->hwptr_done;
1198 	unsigned int wrap = subs->buffer_bytes;
1199 	u8 *dst = urb->transfer_buffer;
1200 	u8 *src = runtime->dma_area;
1201 	u8 marker[] = { 0x05, 0xfa };
1202 	unsigned int queued = 0;
1203 
1204 	/*
1205 	 * The DSP DOP format defines a way to transport DSD samples over
1206 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1207 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1208 	 * 2 additional bytes of actual payload. The whole frame is stored
1209 	 * LSB.
1210 	 *
1211 	 * Hence, for a stereo transport, the buffer layout looks like this,
1212 	 * where L refers to left channel samples and R to right.
1213 	 *
1214 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1215 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1216 	 *   .....
1217 	 *
1218 	 */
1219 
1220 	while (bytes--) {
1221 		if (++subs->dsd_dop.byte_idx == 3) {
1222 			/* frame boundary? */
1223 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1224 			src_idx += 2;
1225 			subs->dsd_dop.byte_idx = 0;
1226 
1227 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1228 				/* alternate the marker */
1229 				subs->dsd_dop.marker++;
1230 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1231 				subs->dsd_dop.channel = 0;
1232 			}
1233 		} else {
1234 			/* stuff the DSD payload */
1235 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1236 
1237 			if (subs->cur_audiofmt->dsd_bitrev)
1238 				dst[dst_idx++] = bitrev8(src[idx]);
1239 			else
1240 				dst[dst_idx++] = src[idx];
1241 			queued++;
1242 		}
1243 	}
1244 
1245 	urb_ctx_queue_advance(subs, urb, queued);
1246 }
1247 
1248 /* copy bit-reversed bytes onto transfer buffer */
1249 static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
1250 					 struct urb *urb, unsigned int bytes)
1251 {
1252 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1253 	const u8 *src = runtime->dma_area;
1254 	u8 *buf = urb->transfer_buffer;
1255 	int i, ofs = subs->hwptr_done;
1256 
1257 	for (i = 0; i < bytes; i++) {
1258 		*buf++ = bitrev8(src[ofs]);
1259 		if (++ofs >= subs->buffer_bytes)
1260 			ofs = 0;
1261 	}
1262 
1263 	urb_ctx_queue_advance(subs, urb, bytes);
1264 }
1265 
1266 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1267 			int offset, int stride, unsigned int bytes)
1268 {
1269 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1270 
1271 	if (subs->hwptr_done + bytes > subs->buffer_bytes) {
1272 		/* err, the transferred area goes over buffer boundary. */
1273 		unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
1274 
1275 		memcpy(urb->transfer_buffer + offset,
1276 		       runtime->dma_area + subs->hwptr_done, bytes1);
1277 		memcpy(urb->transfer_buffer + offset + bytes1,
1278 		       runtime->dma_area, bytes - bytes1);
1279 	} else {
1280 		memcpy(urb->transfer_buffer + offset,
1281 		       runtime->dma_area + subs->hwptr_done, bytes);
1282 	}
1283 
1284 	urb_ctx_queue_advance(subs, urb, bytes);
1285 }
1286 
1287 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1288 				      struct urb *urb, int stride,
1289 				      unsigned int bytes)
1290 {
1291 	__le32 packet_length;
1292 	int i;
1293 
1294 	/* Put __le32 length descriptor at start of each packet. */
1295 	for (i = 0; i < urb->number_of_packets; i++) {
1296 		unsigned int length = urb->iso_frame_desc[i].length;
1297 		unsigned int offset = urb->iso_frame_desc[i].offset;
1298 
1299 		packet_length = cpu_to_le32(length);
1300 		offset += i * sizeof(packet_length);
1301 		urb->iso_frame_desc[i].offset = offset;
1302 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1303 		memcpy(urb->transfer_buffer + offset,
1304 		       &packet_length, sizeof(packet_length));
1305 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1306 			    stride, length);
1307 	}
1308 	/* Adjust transfer size accordingly. */
1309 	bytes += urb->number_of_packets * sizeof(packet_length);
1310 	return bytes;
1311 }
1312 
1313 static void prepare_playback_urb(struct snd_usb_substream *subs,
1314 				 struct urb *urb)
1315 {
1316 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1317 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1318 	struct snd_urb_ctx *ctx = urb->context;
1319 	unsigned int counts, frames, bytes;
1320 	int i, stride, period_elapsed = 0;
1321 	unsigned long flags;
1322 
1323 	stride = ep->stride;
1324 
1325 	frames = 0;
1326 	ctx->queued = 0;
1327 	urb->number_of_packets = 0;
1328 	spin_lock_irqsave(&subs->lock, flags);
1329 	subs->frame_limit += ep->max_urb_frames;
1330 	for (i = 0; i < ctx->packets; i++) {
1331 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i);
1332 		/* set up descriptor */
1333 		urb->iso_frame_desc[i].offset = frames * stride;
1334 		urb->iso_frame_desc[i].length = counts * stride;
1335 		frames += counts;
1336 		urb->number_of_packets++;
1337 		subs->transfer_done += counts;
1338 		if (subs->transfer_done >= runtime->period_size) {
1339 			subs->transfer_done -= runtime->period_size;
1340 			subs->frame_limit = 0;
1341 			period_elapsed = 1;
1342 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1343 				if (subs->transfer_done > 0) {
1344 					/* FIXME: fill-max mode is not
1345 					 * supported yet */
1346 					frames -= subs->transfer_done;
1347 					counts -= subs->transfer_done;
1348 					urb->iso_frame_desc[i].length =
1349 						counts * stride;
1350 					subs->transfer_done = 0;
1351 				}
1352 				i++;
1353 				if (i < ctx->packets) {
1354 					/* add a transfer delimiter */
1355 					urb->iso_frame_desc[i].offset =
1356 						frames * stride;
1357 					urb->iso_frame_desc[i].length = 0;
1358 					urb->number_of_packets++;
1359 				}
1360 				break;
1361 			}
1362 		}
1363 		/* finish at the period boundary or after enough frames */
1364 		if ((period_elapsed ||
1365 				subs->transfer_done >= subs->frame_limit) &&
1366 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1367 			break;
1368 	}
1369 	bytes = frames * stride;
1370 
1371 	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1372 		     subs->cur_audiofmt->dsd_dop)) {
1373 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1374 	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1375 			   subs->cur_audiofmt->dsd_bitrev)) {
1376 		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
1377 	} else {
1378 		/* usual PCM */
1379 		if (!subs->tx_length_quirk)
1380 			copy_to_urb(subs, urb, 0, stride, bytes);
1381 		else
1382 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1383 			/* bytes is now amount of outgoing data */
1384 	}
1385 
1386 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1387 
1388 	if (subs->trigger_tstamp_pending_update) {
1389 		/* this is the first actual URB submitted,
1390 		 * update trigger timestamp to reflect actual start time
1391 		 */
1392 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1393 		subs->trigger_tstamp_pending_update = false;
1394 	}
1395 
1396 	spin_unlock_irqrestore(&subs->lock, flags);
1397 	urb->transfer_buffer_length = bytes;
1398 	if (period_elapsed)
1399 		snd_pcm_period_elapsed(subs->pcm_substream);
1400 }
1401 
1402 /*
1403  * process after playback data complete
1404  * - decrease the delay count again
1405  */
1406 static void retire_playback_urb(struct snd_usb_substream *subs,
1407 			       struct urb *urb)
1408 {
1409 	unsigned long flags;
1410 	struct snd_urb_ctx *ctx = urb->context;
1411 
1412 	spin_lock_irqsave(&subs->lock, flags);
1413 	if (ctx->queued) {
1414 		if (subs->inflight_bytes >= ctx->queued)
1415 			subs->inflight_bytes -= ctx->queued;
1416 		else
1417 			subs->inflight_bytes = 0;
1418 	}
1419 
1420 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1421 	spin_unlock_irqrestore(&subs->lock, flags);
1422 }
1423 
1424 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1425 					      int cmd)
1426 {
1427 	struct snd_usb_substream *subs = substream->runtime->private_data;
1428 	int err;
1429 
1430 	switch (cmd) {
1431 	case SNDRV_PCM_TRIGGER_START:
1432 		subs->trigger_tstamp_pending_update = true;
1433 		fallthrough;
1434 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1435 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1436 					      prepare_playback_urb,
1437 					      retire_playback_urb,
1438 					      subs);
1439 		if (cmd == SNDRV_PCM_TRIGGER_START) {
1440 			err = start_endpoints(subs);
1441 			if (err < 0) {
1442 				snd_usb_endpoint_set_callback(subs->data_endpoint,
1443 							      NULL, NULL, NULL);
1444 				return err;
1445 			}
1446 		}
1447 		subs->running = 1;
1448 		dev_dbg(&subs->dev->dev, "%d:%d Start Playback PCM\n",
1449 			subs->cur_audiofmt->iface,
1450 			subs->cur_audiofmt->altsetting);
1451 		return 0;
1452 	case SNDRV_PCM_TRIGGER_SUSPEND:
1453 	case SNDRV_PCM_TRIGGER_STOP:
1454 		stop_endpoints(subs);
1455 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1456 					      NULL, NULL, NULL);
1457 		subs->running = 0;
1458 		dev_dbg(&subs->dev->dev, "%d:%d Stop Playback PCM\n",
1459 			subs->cur_audiofmt->iface,
1460 			subs->cur_audiofmt->altsetting);
1461 		return 0;
1462 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1463 		/* keep retire_data_urb for delay calculation */
1464 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1465 					      NULL,
1466 					      retire_playback_urb,
1467 					      subs);
1468 		subs->running = 0;
1469 		dev_dbg(&subs->dev->dev, "%d:%d Pause Playback PCM\n",
1470 			subs->cur_audiofmt->iface,
1471 			subs->cur_audiofmt->altsetting);
1472 		return 0;
1473 	}
1474 
1475 	return -EINVAL;
1476 }
1477 
1478 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1479 					     int cmd)
1480 {
1481 	int err;
1482 	struct snd_usb_substream *subs = substream->runtime->private_data;
1483 
1484 	switch (cmd) {
1485 	case SNDRV_PCM_TRIGGER_START:
1486 		err = start_endpoints(subs);
1487 		if (err < 0)
1488 			return err;
1489 		fallthrough;
1490 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1491 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1492 					      NULL, retire_capture_urb,
1493 					      subs);
1494 		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1495 		subs->running = 1;
1496 		dev_dbg(&subs->dev->dev, "%d:%d Start Capture PCM\n",
1497 			subs->cur_audiofmt->iface,
1498 			subs->cur_audiofmt->altsetting);
1499 		return 0;
1500 	case SNDRV_PCM_TRIGGER_SUSPEND:
1501 	case SNDRV_PCM_TRIGGER_STOP:
1502 		stop_endpoints(subs);
1503 		fallthrough;
1504 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1505 		snd_usb_endpoint_set_callback(subs->data_endpoint,
1506 					      NULL, NULL, NULL);
1507 		subs->running = 0;
1508 		dev_dbg(&subs->dev->dev, "%d:%d Stop Capture PCM\n",
1509 			subs->cur_audiofmt->iface,
1510 			subs->cur_audiofmt->altsetting);
1511 		return 0;
1512 	}
1513 
1514 	return -EINVAL;
1515 }
1516 
1517 static const struct snd_pcm_ops snd_usb_playback_ops = {
1518 	.open =		snd_usb_pcm_open,
1519 	.close =	snd_usb_pcm_close,
1520 	.hw_params =	snd_usb_hw_params,
1521 	.hw_free =	snd_usb_hw_free,
1522 	.prepare =	snd_usb_pcm_prepare,
1523 	.trigger =	snd_usb_substream_playback_trigger,
1524 	.sync_stop =	snd_usb_pcm_sync_stop,
1525 	.pointer =	snd_usb_pcm_pointer,
1526 };
1527 
1528 static const struct snd_pcm_ops snd_usb_capture_ops = {
1529 	.open =		snd_usb_pcm_open,
1530 	.close =	snd_usb_pcm_close,
1531 	.hw_params =	snd_usb_hw_params,
1532 	.hw_free =	snd_usb_hw_free,
1533 	.prepare =	snd_usb_pcm_prepare,
1534 	.trigger =	snd_usb_substream_capture_trigger,
1535 	.sync_stop =	snd_usb_pcm_sync_stop,
1536 	.pointer =	snd_usb_pcm_pointer,
1537 };
1538 
1539 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1540 {
1541 	const struct snd_pcm_ops *ops;
1542 
1543 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1544 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1545 	snd_pcm_set_ops(pcm, stream, ops);
1546 }
1547 
1548 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1549 {
1550 	struct snd_pcm *pcm = subs->stream->pcm;
1551 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1552 	struct device *dev = subs->dev->bus->sysdev;
1553 
1554 	if (snd_usb_use_vmalloc)
1555 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1556 					   NULL, 0, 0);
1557 	else
1558 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1559 					   dev, 64*1024, 512*1024);
1560 }
1561