xref: /linux/drivers/usb/gadget/function/u_audio.c (revision ba0ad6ed89fd5dada3b7b65ef2b08e95d449d4ab)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * u_audio.c -- interface to USB gadget "ALSA sound card" utilities
4  *
5  * Copyright (C) 2016
6  * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
7  *
8  * Sound card implementation was cut-and-pasted with changes
9  * from f_uac2.c and has:
10  *    Copyright (C) 2011
11  *    Yadwinder Singh (yadi.brar01@gmail.com)
12  *    Jaswinder Singh (jaswinder.singh@linaro.org)
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <sound/core.h>
18 #include <sound/pcm.h>
19 #include <sound/pcm_params.h>
20 #include <sound/control.h>
21 #include <sound/tlv.h>
22 #include <linux/usb/audio.h>
23 
24 #include "u_audio.h"
25 
26 #define BUFF_SIZE_MAX	(PAGE_SIZE * 16)
27 #define PRD_SIZE_MAX	PAGE_SIZE
28 #define MIN_PERIODS	4
29 
30 enum {
31 	UAC_FBACK_CTRL,
32 	UAC_P_PITCH_CTRL,
33 	UAC_MUTE_CTRL,
34 	UAC_VOLUME_CTRL,
35 	UAC_RATE_CTRL,
36 };
37 
38 /* Runtime data params for one stream */
39 struct uac_rtd_params {
40 	struct snd_uac_chip *uac; /* parent chip */
41 	bool ep_enabled; /* if the ep is enabled */
42 
43 	struct snd_pcm_substream *ss;
44 
45 	/* Ring buffer */
46 	ssize_t hw_ptr;
47 
48 	void *rbuf;
49 
50 	unsigned int pitch;	/* Stream pitch ratio to 1000000 */
51 	unsigned int max_psize;	/* MaxPacketSize of endpoint */
52 
53 	struct usb_request **reqs;
54 
55 	struct usb_request *req_fback; /* Feedback endpoint request */
56 	bool fb_ep_enabled; /* if the ep is enabled */
57 
58   /* Volume/Mute controls and their state */
59   int fu_id; /* Feature Unit ID */
60   struct snd_kcontrol *snd_kctl_volume;
61   struct snd_kcontrol *snd_kctl_mute;
62   s16 volume_min, volume_max, volume_res;
63   s16 volume;
64   int mute;
65 
66 	struct snd_kcontrol *snd_kctl_rate; /* read-only current rate */
67 	int srate; /* selected samplerate */
68 	int active; /* playback/capture running */
69 
70   spinlock_t lock; /* lock for control transfers */
71 
72 };
73 
74 struct snd_uac_chip {
75 	struct g_audio *audio_dev;
76 
77 	struct uac_rtd_params p_prm;
78 	struct uac_rtd_params c_prm;
79 
80 	struct snd_card *card;
81 	struct snd_pcm *pcm;
82 
83 	/* pre-calculated values for playback iso completion */
84 	unsigned long long p_residue_mil;
85 	unsigned int p_interval;
86 	unsigned int p_framesize;
87 };
88 
89 static const struct snd_pcm_hardware uac_pcm_hardware = {
90 	.info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
91 		 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
92 		 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
93 	.rates = SNDRV_PCM_RATE_CONTINUOUS,
94 	.periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
95 	.buffer_bytes_max = BUFF_SIZE_MAX,
96 	.period_bytes_max = PRD_SIZE_MAX,
97 	.periods_min = MIN_PERIODS,
98 };
99 
100 static void u_audio_set_fback_frequency(enum usb_device_speed speed,
101 					struct usb_ep *out_ep,
102 					unsigned long long freq,
103 					unsigned int pitch,
104 					void *buf)
105 {
106 	u32 ff = 0;
107 	const struct usb_endpoint_descriptor *ep_desc;
108 
109 	/*
110 	 * Because the pitch base is 1000000, the final divider here
111 	 * will be 1000 * 1000000 = 1953125 << 9
112 	 *
113 	 * Instead of dealing with big numbers lets fold this 9 left shift
114 	 */
115 
116 	if (speed == USB_SPEED_FULL) {
117 		/*
118 		 * Full-speed feedback endpoints report frequency
119 		 * in samples/frame
120 		 * Format is encoded in Q10.10 left-justified in the 24 bits,
121 		 * so that it has a Q10.14 format.
122 		 *
123 		 * ff = (freq << 14) / 1000
124 		 */
125 		freq <<= 5;
126 	} else {
127 		/*
128 		 * High-speed feedback endpoints report frequency
129 		 * in samples/microframe.
130 		 * Format is encoded in Q12.13 fitted into four bytes so that
131 		 * the binary point is located between the second and the third
132 		 * byte fromat (that is Q16.16)
133 		 *
134 		 * ff = (freq << 16) / 8000
135 		 *
136 		 * Win10 and OSX UAC2 drivers require number of samples per packet
137 		 * in order to honor the feedback value.
138 		 * Linux snd-usb-audio detects the applied bit-shift automatically.
139 		 */
140 		ep_desc = out_ep->desc;
141 		freq <<= 4 + (ep_desc->bInterval - 1);
142 	}
143 
144 	ff = DIV_ROUND_CLOSEST_ULL((freq * pitch), 1953125);
145 
146 	*(__le32 *)buf = cpu_to_le32(ff);
147 }
148 
149 static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
150 {
151 	unsigned int pending;
152 	unsigned int hw_ptr;
153 	int status = req->status;
154 	struct snd_pcm_substream *substream;
155 	struct snd_pcm_runtime *runtime;
156 	struct uac_rtd_params *prm = req->context;
157 	struct snd_uac_chip *uac = prm->uac;
158 	unsigned int frames, p_pktsize;
159 	unsigned long long pitched_rate_mil, p_pktsize_residue_mil,
160 			residue_frames_mil, div_result;
161 
162 	/* i/f shutting down */
163 	if (!prm->ep_enabled) {
164 		usb_ep_free_request(ep, req);
165 		return;
166 	}
167 
168 	if (req->status == -ESHUTDOWN)
169 		return;
170 
171 	/*
172 	 * We can't really do much about bad xfers.
173 	 * Afterall, the ISOCH xfers could fail legitimately.
174 	 */
175 	if (status)
176 		pr_debug("%s: iso_complete status(%d) %d/%d\n",
177 			__func__, status, req->actual, req->length);
178 
179 	substream = prm->ss;
180 
181 	/* Do nothing if ALSA isn't active */
182 	if (!substream)
183 		goto exit;
184 
185 	snd_pcm_stream_lock(substream);
186 
187 	runtime = substream->runtime;
188 	if (!runtime || !snd_pcm_running(substream)) {
189 		snd_pcm_stream_unlock(substream);
190 		goto exit;
191 	}
192 
193 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
194 		/*
195 		 * For each IN packet, take the quotient of the current data
196 		 * rate and the endpoint's interval as the base packet size.
197 		 * If there is a residue from this division, add it to the
198 		 * residue accumulator.
199 		 */
200 		unsigned long long p_interval_mil = uac->p_interval * 1000000ULL;
201 
202 		pitched_rate_mil = (unsigned long long) prm->srate * prm->pitch;
203 		div_result = pitched_rate_mil;
204 		do_div(div_result, uac->p_interval);
205 		do_div(div_result, 1000000);
206 		frames = (unsigned int) div_result;
207 
208 		pr_debug("p_srate %d, pitch %d, interval_mil %llu, frames %d\n",
209 				prm->srate, prm->pitch, p_interval_mil, frames);
210 
211 		p_pktsize = min_t(unsigned int,
212 					uac->p_framesize * frames,
213 					ep->maxpacket);
214 
215 		if (p_pktsize < ep->maxpacket) {
216 			residue_frames_mil = pitched_rate_mil - frames * p_interval_mil;
217 			p_pktsize_residue_mil = uac->p_framesize * residue_frames_mil;
218 		} else
219 			p_pktsize_residue_mil = 0;
220 
221 		req->length = p_pktsize;
222 		uac->p_residue_mil += p_pktsize_residue_mil;
223 
224 		/*
225 		 * Whenever there are more bytes in the accumulator p_residue_mil than we
226 		 * need to add one more sample frame, increase this packet's
227 		 * size and decrease the accumulator.
228 		 */
229 		div_result = uac->p_residue_mil;
230 		do_div(div_result, uac->p_interval);
231 		do_div(div_result, 1000000);
232 		if ((unsigned int) div_result >= uac->p_framesize) {
233 			req->length += uac->p_framesize;
234 			uac->p_residue_mil -= uac->p_framesize * p_interval_mil;
235 			pr_debug("increased req length to %d\n", req->length);
236 		}
237 		pr_debug("remains uac->p_residue_mil %llu\n", uac->p_residue_mil);
238 
239 		req->actual = req->length;
240 	}
241 
242 	hw_ptr = prm->hw_ptr;
243 
244 	/* Pack USB load in ALSA ring buffer */
245 	pending = runtime->dma_bytes - hw_ptr;
246 
247 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
248 		if (unlikely(pending < req->actual)) {
249 			memcpy(req->buf, runtime->dma_area + hw_ptr, pending);
250 			memcpy(req->buf + pending, runtime->dma_area,
251 			       req->actual - pending);
252 		} else {
253 			memcpy(req->buf, runtime->dma_area + hw_ptr,
254 			       req->actual);
255 		}
256 	} else {
257 		if (unlikely(pending < req->actual)) {
258 			memcpy(runtime->dma_area + hw_ptr, req->buf, pending);
259 			memcpy(runtime->dma_area, req->buf + pending,
260 			       req->actual - pending);
261 		} else {
262 			memcpy(runtime->dma_area + hw_ptr, req->buf,
263 			       req->actual);
264 		}
265 	}
266 
267 	/* update hw_ptr after data is copied to memory */
268 	prm->hw_ptr = (hw_ptr + req->actual) % runtime->dma_bytes;
269 	hw_ptr = prm->hw_ptr;
270 	snd_pcm_stream_unlock(substream);
271 
272 	if ((hw_ptr % snd_pcm_lib_period_bytes(substream)) < req->actual)
273 		snd_pcm_period_elapsed(substream);
274 
275 exit:
276 	if (usb_ep_queue(ep, req, GFP_ATOMIC))
277 		dev_err(uac->card->dev, "%d Error!\n", __LINE__);
278 }
279 
280 static void u_audio_iso_fback_complete(struct usb_ep *ep,
281 				       struct usb_request *req)
282 {
283 	struct uac_rtd_params *prm = req->context;
284 	struct snd_uac_chip *uac = prm->uac;
285 	struct g_audio *audio_dev = uac->audio_dev;
286 	int status = req->status;
287 
288 	/* i/f shutting down */
289 	if (!prm->fb_ep_enabled) {
290 		kfree(req->buf);
291 		usb_ep_free_request(ep, req);
292 		return;
293 	}
294 
295 	if (req->status == -ESHUTDOWN)
296 		return;
297 
298 	/*
299 	 * We can't really do much about bad xfers.
300 	 * Afterall, the ISOCH xfers could fail legitimately.
301 	 */
302 	if (status)
303 		pr_debug("%s: iso_complete status(%d) %d/%d\n",
304 			__func__, status, req->actual, req->length);
305 
306 	u_audio_set_fback_frequency(audio_dev->gadget->speed, audio_dev->out_ep,
307 				    prm->srate, prm->pitch,
308 				    req->buf);
309 
310 	if (usb_ep_queue(ep, req, GFP_ATOMIC))
311 		dev_err(uac->card->dev, "%d Error!\n", __LINE__);
312 }
313 
314 static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
315 {
316 	struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
317 	struct uac_rtd_params *prm;
318 	struct g_audio *audio_dev;
319 	struct uac_params *params;
320 	int err = 0;
321 
322 	audio_dev = uac->audio_dev;
323 	params = &audio_dev->params;
324 
325 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
326 		prm = &uac->p_prm;
327 	else
328 		prm = &uac->c_prm;
329 
330 	/* Reset */
331 	prm->hw_ptr = 0;
332 
333 	switch (cmd) {
334 	case SNDRV_PCM_TRIGGER_START:
335 	case SNDRV_PCM_TRIGGER_RESUME:
336 		prm->ss = substream;
337 		break;
338 	case SNDRV_PCM_TRIGGER_STOP:
339 	case SNDRV_PCM_TRIGGER_SUSPEND:
340 		prm->ss = NULL;
341 		break;
342 	default:
343 		err = -EINVAL;
344 	}
345 
346 	/* Clear buffer after Play stops */
347 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
348 		memset(prm->rbuf, 0, prm->max_psize * params->req_number);
349 
350 	return err;
351 }
352 
353 static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
354 {
355 	struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
356 	struct uac_rtd_params *prm;
357 
358 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
359 		prm = &uac->p_prm;
360 	else
361 		prm = &uac->c_prm;
362 
363 	return bytes_to_frames(substream->runtime, prm->hw_ptr);
364 }
365 
366 static u64 uac_ssize_to_fmt(int ssize)
367 {
368 	u64 ret;
369 
370 	switch (ssize) {
371 	case 3:
372 		ret = SNDRV_PCM_FMTBIT_S24_3LE;
373 		break;
374 	case 4:
375 		ret = SNDRV_PCM_FMTBIT_S32_LE;
376 		break;
377 	default:
378 		ret = SNDRV_PCM_FMTBIT_S16_LE;
379 		break;
380 	}
381 
382 	return ret;
383 }
384 
385 static int uac_pcm_open(struct snd_pcm_substream *substream)
386 {
387 	struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
388 	struct snd_pcm_runtime *runtime = substream->runtime;
389 	struct g_audio *audio_dev;
390 	struct uac_params *params;
391 	struct uac_rtd_params *prm;
392 	int p_ssize, c_ssize;
393 	int p_chmask, c_chmask;
394 
395 	audio_dev = uac->audio_dev;
396 	params = &audio_dev->params;
397 	p_ssize = params->p_ssize;
398 	c_ssize = params->c_ssize;
399 	p_chmask = params->p_chmask;
400 	c_chmask = params->c_chmask;
401 	uac->p_residue_mil = 0;
402 
403 	runtime->hw = uac_pcm_hardware;
404 
405 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
406 		runtime->hw.formats = uac_ssize_to_fmt(p_ssize);
407 		runtime->hw.channels_min = num_channels(p_chmask);
408 		prm = &uac->p_prm;
409 	} else {
410 		runtime->hw.formats = uac_ssize_to_fmt(c_ssize);
411 		runtime->hw.channels_min = num_channels(c_chmask);
412 		prm = &uac->c_prm;
413 	}
414 
415 	runtime->hw.period_bytes_min = 2 * prm->max_psize
416 					/ runtime->hw.periods_min;
417 	runtime->hw.rate_min = prm->srate;
418 	runtime->hw.rate_max = runtime->hw.rate_min;
419 	runtime->hw.channels_max = runtime->hw.channels_min;
420 
421 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
422 
423 	return 0;
424 }
425 
426 /* ALSA cries without these function pointers */
427 static int uac_pcm_null(struct snd_pcm_substream *substream)
428 {
429 	return 0;
430 }
431 
432 static const struct snd_pcm_ops uac_pcm_ops = {
433 	.open = uac_pcm_open,
434 	.close = uac_pcm_null,
435 	.trigger = uac_pcm_trigger,
436 	.pointer = uac_pcm_pointer,
437 	.prepare = uac_pcm_null,
438 };
439 
440 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
441 {
442 	struct snd_uac_chip *uac = prm->uac;
443 	struct g_audio *audio_dev;
444 	struct uac_params *params;
445 	int i;
446 
447 	if (!prm->ep_enabled)
448 		return;
449 
450 	audio_dev = uac->audio_dev;
451 	params = &audio_dev->params;
452 
453 	for (i = 0; i < params->req_number; i++) {
454 		if (prm->reqs[i]) {
455 			if (usb_ep_dequeue(ep, prm->reqs[i]))
456 				usb_ep_free_request(ep, prm->reqs[i]);
457 			/*
458 			 * If usb_ep_dequeue() cannot successfully dequeue the
459 			 * request, the request will be freed by the completion
460 			 * callback.
461 			 */
462 
463 			prm->reqs[i] = NULL;
464 		}
465 	}
466 
467 	prm->ep_enabled = false;
468 
469 	if (usb_ep_disable(ep))
470 		dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
471 }
472 
473 static inline void free_ep_fback(struct uac_rtd_params *prm, struct usb_ep *ep)
474 {
475 	struct snd_uac_chip *uac = prm->uac;
476 
477 	if (!prm->fb_ep_enabled)
478 		return;
479 
480 	if (prm->req_fback) {
481 		if (usb_ep_dequeue(ep, prm->req_fback)) {
482 			kfree(prm->req_fback->buf);
483 			usb_ep_free_request(ep, prm->req_fback);
484 		}
485 		prm->req_fback = NULL;
486 	}
487 
488 	prm->fb_ep_enabled = false;
489 
490 	if (usb_ep_disable(ep))
491 		dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
492 }
493 
494 static void set_active(struct uac_rtd_params *prm, bool active)
495 {
496 	// notifying through the Rate ctrl
497 	struct snd_kcontrol *kctl = prm->snd_kctl_rate;
498 	unsigned long flags;
499 
500 	spin_lock_irqsave(&prm->lock, flags);
501 	if (prm->active != active) {
502 		prm->active = active;
503 		snd_ctl_notify(prm->uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
504 				&kctl->id);
505 	}
506 	spin_unlock_irqrestore(&prm->lock, flags);
507 }
508 
509 int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate)
510 {
511 	struct uac_params *params = &audio_dev->params;
512 	struct snd_uac_chip *uac = audio_dev->uac;
513 	struct uac_rtd_params *prm;
514 	int i;
515 	unsigned long flags;
516 
517 	dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
518 	prm = &uac->c_prm;
519 	for (i = 0; i < UAC_MAX_RATES; i++) {
520 		if (params->c_srates[i] == srate) {
521 			spin_lock_irqsave(&prm->lock, flags);
522 			prm->srate = srate;
523 			spin_unlock_irqrestore(&prm->lock, flags);
524 			return 0;
525 		}
526 		if (params->c_srates[i] == 0)
527 			break;
528 	}
529 
530 	return -EINVAL;
531 }
532 EXPORT_SYMBOL_GPL(u_audio_set_capture_srate);
533 
534 int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val)
535 {
536 	struct snd_uac_chip *uac = audio_dev->uac;
537 	struct uac_rtd_params *prm;
538 	unsigned long flags;
539 
540 	prm = &uac->c_prm;
541 	spin_lock_irqsave(&prm->lock, flags);
542 	*val = prm->srate;
543 	spin_unlock_irqrestore(&prm->lock, flags);
544 	return 0;
545 }
546 EXPORT_SYMBOL_GPL(u_audio_get_capture_srate);
547 
548 int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate)
549 {
550 	struct uac_params *params = &audio_dev->params;
551 	struct snd_uac_chip *uac = audio_dev->uac;
552 	struct uac_rtd_params *prm;
553 	int i;
554 	unsigned long flags;
555 
556 	dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
557 	prm = &uac->p_prm;
558 	for (i = 0; i < UAC_MAX_RATES; i++) {
559 		if (params->p_srates[i] == srate) {
560 			spin_lock_irqsave(&prm->lock, flags);
561 			prm->srate = srate;
562 			spin_unlock_irqrestore(&prm->lock, flags);
563 			return 0;
564 		}
565 		if (params->p_srates[i] == 0)
566 			break;
567 	}
568 
569 	return -EINVAL;
570 }
571 EXPORT_SYMBOL_GPL(u_audio_set_playback_srate);
572 
573 int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val)
574 {
575 	struct snd_uac_chip *uac = audio_dev->uac;
576 	struct uac_rtd_params *prm;
577 	unsigned long flags;
578 
579 	prm = &uac->p_prm;
580 	spin_lock_irqsave(&prm->lock, flags);
581 	*val = prm->srate;
582 	spin_unlock_irqrestore(&prm->lock, flags);
583 	return 0;
584 }
585 EXPORT_SYMBOL_GPL(u_audio_get_playback_srate);
586 
587 int u_audio_start_capture(struct g_audio *audio_dev)
588 {
589 	struct snd_uac_chip *uac = audio_dev->uac;
590 	struct usb_gadget *gadget = audio_dev->gadget;
591 	struct device *dev = &gadget->dev;
592 	struct usb_request *req, *req_fback;
593 	struct usb_ep *ep, *ep_fback;
594 	struct uac_rtd_params *prm;
595 	struct uac_params *params = &audio_dev->params;
596 	int req_len, i;
597 
598 	prm = &uac->c_prm;
599 	dev_dbg(dev, "start capture with rate %d\n", prm->srate);
600 	ep = audio_dev->out_ep;
601 	config_ep_by_speed(gadget, &audio_dev->func, ep);
602 	req_len = ep->maxpacket;
603 
604 	prm->ep_enabled = true;
605 	usb_ep_enable(ep);
606 
607 	for (i = 0; i < params->req_number; i++) {
608 		if (!prm->reqs[i]) {
609 			req = usb_ep_alloc_request(ep, GFP_ATOMIC);
610 			if (req == NULL)
611 				return -ENOMEM;
612 
613 			prm->reqs[i] = req;
614 
615 			req->zero = 0;
616 			req->context = prm;
617 			req->length = req_len;
618 			req->complete = u_audio_iso_complete;
619 			req->buf = prm->rbuf + i * ep->maxpacket;
620 		}
621 
622 		if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
623 			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
624 	}
625 
626 	set_active(&uac->c_prm, true);
627 
628 	ep_fback = audio_dev->in_ep_fback;
629 	if (!ep_fback)
630 		return 0;
631 
632 	/* Setup feedback endpoint */
633 	config_ep_by_speed(gadget, &audio_dev->func, ep_fback);
634 	prm->fb_ep_enabled = true;
635 	usb_ep_enable(ep_fback);
636 	req_len = ep_fback->maxpacket;
637 
638 	req_fback = usb_ep_alloc_request(ep_fback, GFP_ATOMIC);
639 	if (req_fback == NULL)
640 		return -ENOMEM;
641 
642 	prm->req_fback = req_fback;
643 	req_fback->zero = 0;
644 	req_fback->context = prm;
645 	req_fback->length = req_len;
646 	req_fback->complete = u_audio_iso_fback_complete;
647 
648 	req_fback->buf = kzalloc(req_len, GFP_ATOMIC);
649 	if (!req_fback->buf)
650 		return -ENOMEM;
651 
652 	/*
653 	 * Configure the feedback endpoint's reported frequency.
654 	 * Always start with original frequency since its deviation can't
655 	 * be meauserd at start of playback
656 	 */
657 	prm->pitch = 1000000;
658 	u_audio_set_fback_frequency(audio_dev->gadget->speed, ep,
659 				    prm->srate, prm->pitch,
660 				    req_fback->buf);
661 
662 	if (usb_ep_queue(ep_fback, req_fback, GFP_ATOMIC))
663 		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
664 
665 	return 0;
666 }
667 EXPORT_SYMBOL_GPL(u_audio_start_capture);
668 
669 void u_audio_stop_capture(struct g_audio *audio_dev)
670 {
671 	struct snd_uac_chip *uac = audio_dev->uac;
672 
673 	set_active(&uac->c_prm, false);
674 	if (audio_dev->in_ep_fback)
675 		free_ep_fback(&uac->c_prm, audio_dev->in_ep_fback);
676 	free_ep(&uac->c_prm, audio_dev->out_ep);
677 }
678 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
679 
680 int u_audio_start_playback(struct g_audio *audio_dev)
681 {
682 	struct snd_uac_chip *uac = audio_dev->uac;
683 	struct usb_gadget *gadget = audio_dev->gadget;
684 	struct device *dev = &gadget->dev;
685 	struct usb_request *req;
686 	struct usb_ep *ep;
687 	struct uac_rtd_params *prm;
688 	struct uac_params *params = &audio_dev->params;
689 	unsigned int factor;
690 	const struct usb_endpoint_descriptor *ep_desc;
691 	int req_len, i;
692 	unsigned int p_pktsize;
693 
694 	prm = &uac->p_prm;
695 	dev_dbg(dev, "start playback with rate %d\n", prm->srate);
696 	ep = audio_dev->in_ep;
697 	config_ep_by_speed(gadget, &audio_dev->func, ep);
698 
699 	ep_desc = ep->desc;
700 	/*
701 	 * Always start with original frequency
702 	 */
703 	prm->pitch = 1000000;
704 
705 	/* pre-calculate the playback endpoint's interval */
706 	if (gadget->speed == USB_SPEED_FULL)
707 		factor = 1000;
708 	else
709 		factor = 8000;
710 
711 	/* pre-compute some values for iso_complete() */
712 	uac->p_framesize = params->p_ssize *
713 			    num_channels(params->p_chmask);
714 	uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
715 	p_pktsize = min_t(unsigned int,
716 				uac->p_framesize *
717 					(prm->srate / uac->p_interval),
718 				ep->maxpacket);
719 
720 	req_len = p_pktsize;
721 	uac->p_residue_mil = 0;
722 
723 	prm->ep_enabled = true;
724 	usb_ep_enable(ep);
725 
726 	for (i = 0; i < params->req_number; i++) {
727 		if (!prm->reqs[i]) {
728 			req = usb_ep_alloc_request(ep, GFP_ATOMIC);
729 			if (req == NULL)
730 				return -ENOMEM;
731 
732 			prm->reqs[i] = req;
733 
734 			req->zero = 0;
735 			req->context = prm;
736 			req->length = req_len;
737 			req->complete = u_audio_iso_complete;
738 			req->buf = prm->rbuf + i * ep->maxpacket;
739 		}
740 
741 		if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
742 			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
743 	}
744 
745 	set_active(&uac->p_prm, true);
746 
747 	return 0;
748 }
749 EXPORT_SYMBOL_GPL(u_audio_start_playback);
750 
751 void u_audio_stop_playback(struct g_audio *audio_dev)
752 {
753 	struct snd_uac_chip *uac = audio_dev->uac;
754 
755 	set_active(&uac->p_prm, false);
756 	free_ep(&uac->p_prm, audio_dev->in_ep);
757 }
758 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
759 
760 void u_audio_suspend(struct g_audio *audio_dev)
761 {
762 	struct snd_uac_chip *uac = audio_dev->uac;
763 
764 	set_active(&uac->p_prm, false);
765 	set_active(&uac->c_prm, false);
766 }
767 EXPORT_SYMBOL_GPL(u_audio_suspend);
768 
769 int u_audio_get_volume(struct g_audio *audio_dev, int playback, s16 *val)
770 {
771 	struct snd_uac_chip *uac = audio_dev->uac;
772 	struct uac_rtd_params *prm;
773 	unsigned long flags;
774 
775 	if (playback)
776 		prm = &uac->p_prm;
777 	else
778 		prm = &uac->c_prm;
779 
780 	spin_lock_irqsave(&prm->lock, flags);
781 	*val = prm->volume;
782 	spin_unlock_irqrestore(&prm->lock, flags);
783 
784 	return 0;
785 }
786 EXPORT_SYMBOL_GPL(u_audio_get_volume);
787 
788 int u_audio_set_volume(struct g_audio *audio_dev, int playback, s16 val)
789 {
790 	struct snd_uac_chip *uac = audio_dev->uac;
791 	struct uac_rtd_params *prm;
792 	unsigned long flags;
793 	int change = 0;
794 
795 	if (playback)
796 		prm = &uac->p_prm;
797 	else
798 		prm = &uac->c_prm;
799 
800 	spin_lock_irqsave(&prm->lock, flags);
801 	val = clamp(val, prm->volume_min, prm->volume_max);
802 	if (prm->volume != val) {
803 		prm->volume = val;
804 		change = 1;
805 	}
806 	spin_unlock_irqrestore(&prm->lock, flags);
807 
808 	if (change)
809 		snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
810 				&prm->snd_kctl_volume->id);
811 
812 	return 0;
813 }
814 EXPORT_SYMBOL_GPL(u_audio_set_volume);
815 
816 int u_audio_get_mute(struct g_audio *audio_dev, int playback, int *val)
817 {
818 	struct snd_uac_chip *uac = audio_dev->uac;
819 	struct uac_rtd_params *prm;
820 	unsigned long flags;
821 
822 	if (playback)
823 		prm = &uac->p_prm;
824 	else
825 		prm = &uac->c_prm;
826 
827 	spin_lock_irqsave(&prm->lock, flags);
828 	*val = prm->mute;
829 	spin_unlock_irqrestore(&prm->lock, flags);
830 
831 	return 0;
832 }
833 EXPORT_SYMBOL_GPL(u_audio_get_mute);
834 
835 int u_audio_set_mute(struct g_audio *audio_dev, int playback, int val)
836 {
837 	struct snd_uac_chip *uac = audio_dev->uac;
838 	struct uac_rtd_params *prm;
839 	unsigned long flags;
840 	int change = 0;
841 	int mute;
842 
843 	if (playback)
844 		prm = &uac->p_prm;
845 	else
846 		prm = &uac->c_prm;
847 
848 	mute = val ? 1 : 0;
849 
850 	spin_lock_irqsave(&prm->lock, flags);
851 	if (prm->mute != mute) {
852 		prm->mute = mute;
853 		change = 1;
854 	}
855 	spin_unlock_irqrestore(&prm->lock, flags);
856 
857 	if (change)
858 		snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
859 			       &prm->snd_kctl_mute->id);
860 
861 	return 0;
862 }
863 EXPORT_SYMBOL_GPL(u_audio_set_mute);
864 
865 
866 static int u_audio_pitch_info(struct snd_kcontrol *kcontrol,
867 				   struct snd_ctl_elem_info *uinfo)
868 {
869 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
870 	struct snd_uac_chip *uac = prm->uac;
871 	struct g_audio *audio_dev = uac->audio_dev;
872 	struct uac_params *params = &audio_dev->params;
873 	unsigned int pitch_min, pitch_max;
874 
875 	pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
876 	pitch_max = (1000 + params->fb_max) * 1000;
877 
878 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
879 	uinfo->count = 1;
880 	uinfo->value.integer.min = pitch_min;
881 	uinfo->value.integer.max = pitch_max;
882 	uinfo->value.integer.step = 1;
883 	return 0;
884 }
885 
886 static int u_audio_pitch_get(struct snd_kcontrol *kcontrol,
887 				   struct snd_ctl_elem_value *ucontrol)
888 {
889 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
890 
891 	ucontrol->value.integer.value[0] = prm->pitch;
892 
893 	return 0;
894 }
895 
896 static int u_audio_pitch_put(struct snd_kcontrol *kcontrol,
897 				  struct snd_ctl_elem_value *ucontrol)
898 {
899 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
900 	struct snd_uac_chip *uac = prm->uac;
901 	struct g_audio *audio_dev = uac->audio_dev;
902 	struct uac_params *params = &audio_dev->params;
903 	unsigned int val;
904 	unsigned int pitch_min, pitch_max;
905 	int change = 0;
906 
907 	pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
908 	pitch_max = (1000 + params->fb_max) * 1000;
909 
910 	val = ucontrol->value.integer.value[0];
911 
912 	if (val < pitch_min)
913 		val = pitch_min;
914 	if (val > pitch_max)
915 		val = pitch_max;
916 
917 	if (prm->pitch != val) {
918 		prm->pitch = val;
919 		change = 1;
920 	}
921 
922 	return change;
923 }
924 
925 static int u_audio_mute_info(struct snd_kcontrol *kcontrol,
926 				   struct snd_ctl_elem_info *uinfo)
927 {
928 	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
929 	uinfo->count = 1;
930 	uinfo->value.integer.min = 0;
931 	uinfo->value.integer.max = 1;
932 	uinfo->value.integer.step = 1;
933 
934 	return 0;
935 }
936 
937 static int u_audio_mute_get(struct snd_kcontrol *kcontrol,
938 				   struct snd_ctl_elem_value *ucontrol)
939 {
940 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
941 	unsigned long flags;
942 
943 	spin_lock_irqsave(&prm->lock, flags);
944 	ucontrol->value.integer.value[0] = !prm->mute;
945 	spin_unlock_irqrestore(&prm->lock, flags);
946 
947 	return 0;
948 }
949 
950 static int u_audio_mute_put(struct snd_kcontrol *kcontrol,
951 				  struct snd_ctl_elem_value *ucontrol)
952 {
953 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
954 	struct snd_uac_chip *uac = prm->uac;
955 	struct g_audio *audio_dev = uac->audio_dev;
956 	unsigned int val;
957 	unsigned long flags;
958 	int change = 0;
959 
960 	val = !ucontrol->value.integer.value[0];
961 
962 	spin_lock_irqsave(&prm->lock, flags);
963 	if (val != prm->mute) {
964 		prm->mute = val;
965 		change = 1;
966 	}
967 	spin_unlock_irqrestore(&prm->lock, flags);
968 
969 	if (change && audio_dev->notify)
970 		audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_MUTE);
971 
972 	return change;
973 }
974 
975 /*
976  * TLV callback for mixer volume controls
977  */
978 static int u_audio_volume_tlv(struct snd_kcontrol *kcontrol, int op_flag,
979 			 unsigned int size, unsigned int __user *_tlv)
980 {
981 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
982 	DECLARE_TLV_DB_MINMAX(scale, 0, 0);
983 
984 	if (size < sizeof(scale))
985 		return -ENOMEM;
986 
987 	/* UAC volume resolution is 1/256 dB, TLV is 1/100 dB */
988 	scale[2] = (prm->volume_min * 100) / 256;
989 	scale[3] = (prm->volume_max * 100) / 256;
990 	if (copy_to_user(_tlv, scale, sizeof(scale)))
991 		return -EFAULT;
992 
993 	return 0;
994 }
995 
996 static int u_audio_volume_info(struct snd_kcontrol *kcontrol,
997 				   struct snd_ctl_elem_info *uinfo)
998 {
999 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1000 
1001 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1002 	uinfo->count = 1;
1003 	uinfo->value.integer.min = 0;
1004 	uinfo->value.integer.max =
1005 		(prm->volume_max - prm->volume_min + prm->volume_res - 1)
1006 		/ prm->volume_res;
1007 	uinfo->value.integer.step = 1;
1008 
1009 	return 0;
1010 }
1011 
1012 static int u_audio_volume_get(struct snd_kcontrol *kcontrol,
1013 				   struct snd_ctl_elem_value *ucontrol)
1014 {
1015 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1016 	unsigned long flags;
1017 
1018 	spin_lock_irqsave(&prm->lock, flags);
1019 	ucontrol->value.integer.value[0] =
1020 			(prm->volume - prm->volume_min) / prm->volume_res;
1021 	spin_unlock_irqrestore(&prm->lock, flags);
1022 
1023 	return 0;
1024 }
1025 
1026 static int u_audio_volume_put(struct snd_kcontrol *kcontrol,
1027 				  struct snd_ctl_elem_value *ucontrol)
1028 {
1029 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1030 	struct snd_uac_chip *uac = prm->uac;
1031 	struct g_audio *audio_dev = uac->audio_dev;
1032 	unsigned int val;
1033 	s16 volume;
1034 	unsigned long flags;
1035 	int change = 0;
1036 
1037 	val = ucontrol->value.integer.value[0];
1038 
1039 	spin_lock_irqsave(&prm->lock, flags);
1040 	volume = (val * prm->volume_res) + prm->volume_min;
1041 	volume = clamp(volume, prm->volume_min, prm->volume_max);
1042 	if (volume != prm->volume) {
1043 		prm->volume = volume;
1044 		change = 1;
1045 	}
1046 	spin_unlock_irqrestore(&prm->lock, flags);
1047 
1048 	if (change && audio_dev->notify)
1049 		audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_VOLUME);
1050 
1051 	return change;
1052 }
1053 
1054 static int get_max_srate(const int *srates)
1055 {
1056 	int i, max_srate = 0;
1057 
1058 	for (i = 0; i < UAC_MAX_RATES; i++) {
1059 		if (srates[i] == 0)
1060 			break;
1061 		if (srates[i] > max_srate)
1062 			max_srate = srates[i];
1063 	}
1064 	return max_srate;
1065 }
1066 
1067 static int get_min_srate(const int *srates)
1068 {
1069 	int i, min_srate = INT_MAX;
1070 
1071 	for (i = 0; i < UAC_MAX_RATES; i++) {
1072 		if (srates[i] == 0)
1073 			break;
1074 		if (srates[i] < min_srate)
1075 			min_srate = srates[i];
1076 	}
1077 	return min_srate;
1078 }
1079 
1080 static int u_audio_rate_info(struct snd_kcontrol *kcontrol,
1081 				struct snd_ctl_elem_info *uinfo)
1082 {
1083 	const int *srates;
1084 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1085 	struct snd_uac_chip *uac = prm->uac;
1086 	struct g_audio *audio_dev = uac->audio_dev;
1087 	struct uac_params *params = &audio_dev->params;
1088 
1089 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1090 	uinfo->count = 1;
1091 
1092 	if (prm == &uac->c_prm)
1093 		srates = params->c_srates;
1094 	else
1095 		srates = params->p_srates;
1096 	uinfo->value.integer.min = get_min_srate(srates);
1097 	uinfo->value.integer.max = get_max_srate(srates);
1098 	return 0;
1099 }
1100 
1101 static int u_audio_rate_get(struct snd_kcontrol *kcontrol,
1102 						 struct snd_ctl_elem_value *ucontrol)
1103 {
1104 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1105 	unsigned long flags;
1106 
1107 	spin_lock_irqsave(&prm->lock, flags);
1108 	if (prm->active)
1109 		ucontrol->value.integer.value[0] = prm->srate;
1110 	else
1111 		/* not active: reporting zero rate */
1112 		ucontrol->value.integer.value[0] = 0;
1113 	spin_unlock_irqrestore(&prm->lock, flags);
1114 	return 0;
1115 }
1116 
1117 static struct snd_kcontrol_new u_audio_controls[]  = {
1118   [UAC_FBACK_CTRL] {
1119     .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1120     .name =         "Capture Pitch 1000000",
1121     .info =         u_audio_pitch_info,
1122     .get =          u_audio_pitch_get,
1123     .put =          u_audio_pitch_put,
1124   },
1125 	[UAC_P_PITCH_CTRL] {
1126 		.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1127 		.name =         "Playback Pitch 1000000",
1128 		.info =         u_audio_pitch_info,
1129 		.get =          u_audio_pitch_get,
1130 		.put =          u_audio_pitch_put,
1131 	},
1132   [UAC_MUTE_CTRL] {
1133 		.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
1134 		.name =		"", /* will be filled later */
1135 		.info =		u_audio_mute_info,
1136 		.get =		u_audio_mute_get,
1137 		.put =		u_audio_mute_put,
1138 	},
1139 	[UAC_VOLUME_CTRL] {
1140 		.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
1141 		.name =		"", /* will be filled later */
1142 		.info =		u_audio_volume_info,
1143 		.get =		u_audio_volume_get,
1144 		.put =		u_audio_volume_put,
1145 	},
1146 	[UAC_RATE_CTRL] {
1147 		.iface =	SNDRV_CTL_ELEM_IFACE_PCM,
1148 		.name =		"", /* will be filled later */
1149 		.access =	SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
1150 		.info =		u_audio_rate_info,
1151 		.get =		u_audio_rate_get,
1152 	},
1153 };
1154 
1155 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
1156 					const char *card_name)
1157 {
1158 	struct snd_uac_chip *uac;
1159 	struct snd_card *card;
1160 	struct snd_pcm *pcm;
1161 	struct snd_kcontrol *kctl;
1162 	struct uac_params *params;
1163 	int p_chmask, c_chmask;
1164 	int i, err;
1165 
1166 	if (!g_audio)
1167 		return -EINVAL;
1168 
1169 	uac = kzalloc(sizeof(*uac), GFP_KERNEL);
1170 	if (!uac)
1171 		return -ENOMEM;
1172 	g_audio->uac = uac;
1173 	uac->audio_dev = g_audio;
1174 
1175 	params = &g_audio->params;
1176 	p_chmask = params->p_chmask;
1177 	c_chmask = params->c_chmask;
1178 
1179 	if (c_chmask) {
1180 		struct uac_rtd_params *prm = &uac->c_prm;
1181 
1182 		spin_lock_init(&prm->lock);
1183 		uac->c_prm.uac = uac;
1184 		prm->max_psize = g_audio->out_ep_maxpsize;
1185 		prm->srate = params->c_srates[0];
1186 
1187 		prm->reqs = kcalloc(params->req_number,
1188 				    sizeof(struct usb_request *),
1189 				    GFP_KERNEL);
1190 		if (!prm->reqs) {
1191 			err = -ENOMEM;
1192 			goto fail;
1193 		}
1194 
1195 		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
1196 				GFP_KERNEL);
1197 		if (!prm->rbuf) {
1198 			prm->max_psize = 0;
1199 			err = -ENOMEM;
1200 			goto fail;
1201 		}
1202 	}
1203 
1204 	if (p_chmask) {
1205 		struct uac_rtd_params *prm = &uac->p_prm;
1206 
1207 		spin_lock_init(&prm->lock);
1208 		uac->p_prm.uac = uac;
1209 		prm->max_psize = g_audio->in_ep_maxpsize;
1210 		prm->srate = params->p_srates[0];
1211 
1212 		prm->reqs = kcalloc(params->req_number,
1213 				    sizeof(struct usb_request *),
1214 				    GFP_KERNEL);
1215 		if (!prm->reqs) {
1216 			err = -ENOMEM;
1217 			goto fail;
1218 		}
1219 
1220 		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
1221 				GFP_KERNEL);
1222 		if (!prm->rbuf) {
1223 			prm->max_psize = 0;
1224 			err = -ENOMEM;
1225 			goto fail;
1226 		}
1227 	}
1228 
1229 	/* Choose any slot, with no id */
1230 	err = snd_card_new(&g_audio->gadget->dev,
1231 			-1, NULL, THIS_MODULE, 0, &card);
1232 	if (err < 0)
1233 		goto fail;
1234 
1235 	uac->card = card;
1236 
1237 	/*
1238 	 * Create first PCM device
1239 	 * Create a substream only for non-zero channel streams
1240 	 */
1241 	err = snd_pcm_new(uac->card, pcm_name, 0,
1242 			       p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
1243 	if (err < 0)
1244 		goto snd_fail;
1245 
1246 	strscpy(pcm->name, pcm_name, sizeof(pcm->name));
1247 	pcm->private_data = uac;
1248 	uac->pcm = pcm;
1249 
1250 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
1251 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
1252 
1253 	/*
1254 	 * Create mixer and controls
1255 	 * Create only if it's required on USB side
1256 	 */
1257 	if ((c_chmask && g_audio->in_ep_fback)
1258 			|| (p_chmask && params->p_fu.id)
1259 			|| (c_chmask && params->c_fu.id))
1260 		strscpy(card->mixername, card_name, sizeof(card->driver));
1261 
1262 	if (c_chmask && g_audio->in_ep_fback) {
1263 		kctl = snd_ctl_new1(&u_audio_controls[UAC_FBACK_CTRL],
1264 				    &uac->c_prm);
1265 		if (!kctl) {
1266 			err = -ENOMEM;
1267 			goto snd_fail;
1268 		}
1269 
1270 		kctl->id.device = pcm->device;
1271 		kctl->id.subdevice = 0;
1272 
1273 		err = snd_ctl_add(card, kctl);
1274 		if (err < 0)
1275 			goto snd_fail;
1276 	}
1277 
1278 	if (p_chmask) {
1279 		kctl = snd_ctl_new1(&u_audio_controls[UAC_P_PITCH_CTRL],
1280 				    &uac->p_prm);
1281 		if (!kctl) {
1282 			err = -ENOMEM;
1283 			goto snd_fail;
1284 		}
1285 
1286 		kctl->id.device = pcm->device;
1287 		kctl->id.subdevice = 0;
1288 
1289 		err = snd_ctl_add(card, kctl);
1290 		if (err < 0)
1291 			goto snd_fail;
1292 	}
1293 
1294 	for (i = 0; i <= SNDRV_PCM_STREAM_LAST; i++) {
1295 		struct uac_rtd_params *prm;
1296 		struct uac_fu_params *fu;
1297 		char ctrl_name[24];
1298 		char *direction;
1299 
1300 		if (!pcm->streams[i].substream_count)
1301 			continue;
1302 
1303 		if (i == SNDRV_PCM_STREAM_PLAYBACK) {
1304 			prm = &uac->p_prm;
1305 			fu = &params->p_fu;
1306 			direction = "Playback";
1307 		} else {
1308 			prm = &uac->c_prm;
1309 			fu = &params->c_fu;
1310 			direction = "Capture";
1311 		}
1312 
1313 		prm->fu_id = fu->id;
1314 
1315 		if (fu->mute_present) {
1316 			snprintf(ctrl_name, sizeof(ctrl_name),
1317 					"PCM %s Switch", direction);
1318 
1319 			u_audio_controls[UAC_MUTE_CTRL].name = ctrl_name;
1320 
1321 			kctl = snd_ctl_new1(&u_audio_controls[UAC_MUTE_CTRL],
1322 					    prm);
1323 			if (!kctl) {
1324 				err = -ENOMEM;
1325 				goto snd_fail;
1326 			}
1327 
1328 			kctl->id.device = pcm->device;
1329 			kctl->id.subdevice = 0;
1330 
1331 			err = snd_ctl_add(card, kctl);
1332 			if (err < 0)
1333 				goto snd_fail;
1334 			prm->snd_kctl_mute = kctl;
1335 			prm->mute = 0;
1336 		}
1337 
1338 		if (fu->volume_present) {
1339 			snprintf(ctrl_name, sizeof(ctrl_name),
1340 					"PCM %s Volume", direction);
1341 
1342 			u_audio_controls[UAC_VOLUME_CTRL].name = ctrl_name;
1343 
1344 			kctl = snd_ctl_new1(&u_audio_controls[UAC_VOLUME_CTRL],
1345 					    prm);
1346 			if (!kctl) {
1347 				err = -ENOMEM;
1348 				goto snd_fail;
1349 			}
1350 
1351 			kctl->id.device = pcm->device;
1352 			kctl->id.subdevice = 0;
1353 
1354 
1355 			kctl->tlv.c = u_audio_volume_tlv;
1356 			kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ |
1357 					SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1358 
1359 			err = snd_ctl_add(card, kctl);
1360 			if (err < 0)
1361 				goto snd_fail;
1362 			prm->snd_kctl_volume = kctl;
1363 			prm->volume = fu->volume_max;
1364 			prm->volume_max = fu->volume_max;
1365 			prm->volume_min = fu->volume_min;
1366 			prm->volume_res = fu->volume_res;
1367 		}
1368 
1369 		/* Add rate control */
1370 		snprintf(ctrl_name, sizeof(ctrl_name),
1371 				"%s Rate", direction);
1372 		u_audio_controls[UAC_RATE_CTRL].name = ctrl_name;
1373 
1374 		kctl = snd_ctl_new1(&u_audio_controls[UAC_RATE_CTRL], prm);
1375 		if (!kctl) {
1376 			err = -ENOMEM;
1377 			goto snd_fail;
1378 		}
1379 
1380 		kctl->id.device = pcm->device;
1381 		kctl->id.subdevice = 0;
1382 
1383 		err = snd_ctl_add(card, kctl);
1384 		if (err < 0)
1385 			goto snd_fail;
1386 		prm->snd_kctl_rate = kctl;
1387 	}
1388 
1389 	strscpy(card->driver, card_name, sizeof(card->driver));
1390 	strscpy(card->shortname, card_name, sizeof(card->shortname));
1391 	sprintf(card->longname, "%s %i", card_name, card->dev->id);
1392 
1393 	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
1394 				       NULL, 0, BUFF_SIZE_MAX);
1395 
1396 	err = snd_card_register(card);
1397 
1398 	if (!err)
1399 		return 0;
1400 
1401 snd_fail:
1402 	snd_card_free(card);
1403 fail:
1404 	kfree(uac->p_prm.reqs);
1405 	kfree(uac->c_prm.reqs);
1406 	kfree(uac->p_prm.rbuf);
1407 	kfree(uac->c_prm.rbuf);
1408 	kfree(uac);
1409 
1410 	return err;
1411 }
1412 EXPORT_SYMBOL_GPL(g_audio_setup);
1413 
1414 void g_audio_cleanup(struct g_audio *g_audio)
1415 {
1416 	struct snd_uac_chip *uac;
1417 	struct snd_card *card;
1418 
1419 	if (!g_audio || !g_audio->uac)
1420 		return;
1421 
1422 	uac = g_audio->uac;
1423 	card = uac->card;
1424 	if (card)
1425 		snd_card_free_when_closed(card);
1426 
1427 	kfree(uac->p_prm.reqs);
1428 	kfree(uac->c_prm.reqs);
1429 	kfree(uac->p_prm.rbuf);
1430 	kfree(uac->c_prm.rbuf);
1431 	kfree(uac);
1432 }
1433 EXPORT_SYMBOL_GPL(g_audio_cleanup);
1434 
1435 MODULE_LICENSE("GPL");
1436 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
1437 MODULE_AUTHOR("Ruslan Bilovol");
1438