xref: /linux/drivers/usb/gadget/function/u_audio.c (revision 1b78070aaef63512688aebfbc82365ef9d6660f1)
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_ctl_elem_id snd_kctl_volume_id;
61   struct snd_ctl_elem_id snd_kctl_mute_id;
62   s16 volume_min, volume_max, volume_res;
63   s16 volume;
64   int mute;
65 
66 	struct snd_ctl_elem_id snd_kctl_rate_id; /* 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 	unsigned long flags;
498 
499 	spin_lock_irqsave(&prm->lock, flags);
500 	if (prm->active != active) {
501 		prm->active = active;
502 		snd_ctl_notify(prm->uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
503 				&prm->snd_kctl_rate_id);
504 	}
505 	spin_unlock_irqrestore(&prm->lock, flags);
506 }
507 
508 int u_audio_set_capture_srate(struct g_audio *audio_dev, int srate)
509 {
510 	struct uac_params *params = &audio_dev->params;
511 	struct snd_uac_chip *uac = audio_dev->uac;
512 	struct uac_rtd_params *prm;
513 	int i;
514 	unsigned long flags;
515 
516 	dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
517 	prm = &uac->c_prm;
518 	for (i = 0; i < UAC_MAX_RATES; i++) {
519 		if (params->c_srates[i] == srate) {
520 			spin_lock_irqsave(&prm->lock, flags);
521 			prm->srate = srate;
522 			spin_unlock_irqrestore(&prm->lock, flags);
523 			return 0;
524 		}
525 		if (params->c_srates[i] == 0)
526 			break;
527 	}
528 
529 	return -EINVAL;
530 }
531 EXPORT_SYMBOL_GPL(u_audio_set_capture_srate);
532 
533 int u_audio_get_capture_srate(struct g_audio *audio_dev, u32 *val)
534 {
535 	struct snd_uac_chip *uac = audio_dev->uac;
536 	struct uac_rtd_params *prm;
537 	unsigned long flags;
538 
539 	prm = &uac->c_prm;
540 	spin_lock_irqsave(&prm->lock, flags);
541 	*val = prm->srate;
542 	spin_unlock_irqrestore(&prm->lock, flags);
543 	return 0;
544 }
545 EXPORT_SYMBOL_GPL(u_audio_get_capture_srate);
546 
547 int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate)
548 {
549 	struct uac_params *params = &audio_dev->params;
550 	struct snd_uac_chip *uac = audio_dev->uac;
551 	struct uac_rtd_params *prm;
552 	int i;
553 	unsigned long flags;
554 
555 	dev_dbg(&audio_dev->gadget->dev, "%s: srate %d\n", __func__, srate);
556 	prm = &uac->p_prm;
557 	for (i = 0; i < UAC_MAX_RATES; i++) {
558 		if (params->p_srates[i] == srate) {
559 			spin_lock_irqsave(&prm->lock, flags);
560 			prm->srate = srate;
561 			spin_unlock_irqrestore(&prm->lock, flags);
562 			return 0;
563 		}
564 		if (params->p_srates[i] == 0)
565 			break;
566 	}
567 
568 	return -EINVAL;
569 }
570 EXPORT_SYMBOL_GPL(u_audio_set_playback_srate);
571 
572 int u_audio_get_playback_srate(struct g_audio *audio_dev, u32 *val)
573 {
574 	struct snd_uac_chip *uac = audio_dev->uac;
575 	struct uac_rtd_params *prm;
576 	unsigned long flags;
577 
578 	prm = &uac->p_prm;
579 	spin_lock_irqsave(&prm->lock, flags);
580 	*val = prm->srate;
581 	spin_unlock_irqrestore(&prm->lock, flags);
582 	return 0;
583 }
584 EXPORT_SYMBOL_GPL(u_audio_get_playback_srate);
585 
586 int u_audio_start_capture(struct g_audio *audio_dev)
587 {
588 	struct snd_uac_chip *uac = audio_dev->uac;
589 	struct usb_gadget *gadget = audio_dev->gadget;
590 	struct device *dev = &gadget->dev;
591 	struct usb_request *req, *req_fback;
592 	struct usb_ep *ep, *ep_fback;
593 	struct uac_rtd_params *prm;
594 	struct uac_params *params = &audio_dev->params;
595 	int req_len, i, ret;
596 
597 	prm = &uac->c_prm;
598 	dev_dbg(dev, "start capture with rate %d\n", prm->srate);
599 	ep = audio_dev->out_ep;
600 	ret = config_ep_by_speed(gadget, &audio_dev->func, ep);
601 	if (ret < 0) {
602 		dev_err(dev, "config_ep_by_speed for out_ep failed (%d)\n", ret);
603 		return ret;
604 	}
605 
606 	req_len = ep->maxpacket;
607 
608 	prm->ep_enabled = true;
609 	ret = usb_ep_enable(ep);
610 	if (ret < 0) {
611 		dev_err(dev, "usb_ep_enable failed for out_ep (%d)\n", ret);
612 		return ret;
613 	}
614 
615 	for (i = 0; i < params->req_number; i++) {
616 		if (!prm->reqs[i]) {
617 			req = usb_ep_alloc_request(ep, GFP_ATOMIC);
618 			if (req == NULL)
619 				return -ENOMEM;
620 
621 			prm->reqs[i] = req;
622 
623 			req->zero = 0;
624 			req->context = prm;
625 			req->length = req_len;
626 			req->complete = u_audio_iso_complete;
627 			req->buf = prm->rbuf + i * ep->maxpacket;
628 		}
629 
630 		if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
631 			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
632 	}
633 
634 	set_active(&uac->c_prm, true);
635 
636 	ep_fback = audio_dev->in_ep_fback;
637 	if (!ep_fback)
638 		return 0;
639 
640 	/* Setup feedback endpoint */
641 	ret = config_ep_by_speed(gadget, &audio_dev->func, ep_fback);
642 	if (ret < 0) {
643 		dev_err(dev, "config_ep_by_speed in_ep_fback failed (%d)\n", ret);
644 		goto err_out_ep;
645 	}
646 
647 	ret = usb_ep_enable(ep_fback);
648 	if (ret < 0) {
649 		dev_err(dev, "usb_ep_enable failed for in_ep_fback (%d)\n", ret);
650 		goto err_out_ep;
651 	}
652 	prm->fb_ep_enabled = true;
653 	req_len = ep_fback->maxpacket;
654 
655 	req_fback = usb_ep_alloc_request(ep_fback, GFP_ATOMIC);
656 	if (req_fback == NULL)
657 		return -ENOMEM;
658 
659 	prm->req_fback = req_fback;
660 	req_fback->zero = 0;
661 	req_fback->context = prm;
662 	req_fback->length = req_len;
663 	req_fback->complete = u_audio_iso_fback_complete;
664 
665 	req_fback->buf = kzalloc(req_len, GFP_ATOMIC);
666 	if (!req_fback->buf)
667 		return -ENOMEM;
668 
669 	/*
670 	 * Configure the feedback endpoint's reported frequency.
671 	 * Always start with original frequency since its deviation can't
672 	 * be meauserd at start of playback
673 	 */
674 	prm->pitch = 1000000;
675 	u_audio_set_fback_frequency(audio_dev->gadget->speed, ep,
676 				    prm->srate, prm->pitch,
677 				    req_fback->buf);
678 
679 	if (usb_ep_queue(ep_fback, req_fback, GFP_ATOMIC))
680 		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
681 
682 	return 0;
683 
684 err_out_ep:
685 	set_active(prm, false);
686 	free_ep(prm, ep);
687 
688 	return ret;
689 }
690 EXPORT_SYMBOL_GPL(u_audio_start_capture);
691 
692 void u_audio_stop_capture(struct g_audio *audio_dev)
693 {
694 	struct snd_uac_chip *uac = audio_dev->uac;
695 
696 	set_active(&uac->c_prm, false);
697 	if (audio_dev->in_ep_fback)
698 		free_ep_fback(&uac->c_prm, audio_dev->in_ep_fback);
699 	free_ep(&uac->c_prm, audio_dev->out_ep);
700 }
701 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
702 
703 int u_audio_start_playback(struct g_audio *audio_dev)
704 {
705 	struct snd_uac_chip *uac = audio_dev->uac;
706 	struct usb_gadget *gadget = audio_dev->gadget;
707 	struct device *dev = &gadget->dev;
708 	struct usb_request *req;
709 	struct usb_ep *ep;
710 	struct uac_rtd_params *prm;
711 	struct uac_params *params = &audio_dev->params;
712 	unsigned int factor;
713 	const struct usb_endpoint_descriptor *ep_desc;
714 	int req_len, i, ret;
715 	unsigned int p_pktsize;
716 
717 	prm = &uac->p_prm;
718 	dev_dbg(dev, "start playback with rate %d\n", prm->srate);
719 	ep = audio_dev->in_ep;
720 	ret = config_ep_by_speed(gadget, &audio_dev->func, ep);
721 	if (ret < 0) {
722 		dev_err(dev, "config_ep_by_speed for in_ep failed (%d)\n", ret);
723 		return ret;
724 	}
725 
726 	ep_desc = ep->desc;
727 	/*
728 	 * Always start with original frequency
729 	 */
730 	prm->pitch = 1000000;
731 
732 	/* pre-calculate the playback endpoint's interval */
733 	if (gadget->speed == USB_SPEED_FULL)
734 		factor = 1000;
735 	else
736 		factor = 8000;
737 
738 	/* pre-compute some values for iso_complete() */
739 	uac->p_framesize = params->p_ssize *
740 			    num_channels(params->p_chmask);
741 	uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
742 	p_pktsize = min_t(unsigned int,
743 				uac->p_framesize *
744 					(prm->srate / uac->p_interval),
745 				ep->maxpacket);
746 
747 	req_len = p_pktsize;
748 	uac->p_residue_mil = 0;
749 
750 	prm->ep_enabled = true;
751 	ret = usb_ep_enable(ep);
752 	if (ret < 0) {
753 		dev_err(dev, "usb_ep_enable failed for in_ep (%d)\n", ret);
754 		return ret;
755 	}
756 
757 	for (i = 0; i < params->req_number; i++) {
758 		if (!prm->reqs[i]) {
759 			req = usb_ep_alloc_request(ep, GFP_ATOMIC);
760 			if (req == NULL)
761 				return -ENOMEM;
762 
763 			prm->reqs[i] = req;
764 
765 			req->zero = 0;
766 			req->context = prm;
767 			req->length = req_len;
768 			req->complete = u_audio_iso_complete;
769 			req->buf = prm->rbuf + i * ep->maxpacket;
770 		}
771 
772 		if (usb_ep_queue(ep, prm->reqs[i], GFP_ATOMIC))
773 			dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
774 	}
775 
776 	set_active(&uac->p_prm, true);
777 
778 	return 0;
779 }
780 EXPORT_SYMBOL_GPL(u_audio_start_playback);
781 
782 void u_audio_stop_playback(struct g_audio *audio_dev)
783 {
784 	struct snd_uac_chip *uac = audio_dev->uac;
785 
786 	set_active(&uac->p_prm, false);
787 	free_ep(&uac->p_prm, audio_dev->in_ep);
788 }
789 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
790 
791 void u_audio_suspend(struct g_audio *audio_dev)
792 {
793 	struct snd_uac_chip *uac = audio_dev->uac;
794 
795 	set_active(&uac->p_prm, false);
796 	set_active(&uac->c_prm, false);
797 }
798 EXPORT_SYMBOL_GPL(u_audio_suspend);
799 
800 int u_audio_get_volume(struct g_audio *audio_dev, int playback, s16 *val)
801 {
802 	struct snd_uac_chip *uac = audio_dev->uac;
803 	struct uac_rtd_params *prm;
804 	unsigned long flags;
805 
806 	if (playback)
807 		prm = &uac->p_prm;
808 	else
809 		prm = &uac->c_prm;
810 
811 	spin_lock_irqsave(&prm->lock, flags);
812 	*val = prm->volume;
813 	spin_unlock_irqrestore(&prm->lock, flags);
814 
815 	return 0;
816 }
817 EXPORT_SYMBOL_GPL(u_audio_get_volume);
818 
819 int u_audio_set_volume(struct g_audio *audio_dev, int playback, s16 val)
820 {
821 	struct snd_uac_chip *uac = audio_dev->uac;
822 	struct uac_rtd_params *prm;
823 	unsigned long flags;
824 	int change = 0;
825 
826 	if (playback)
827 		prm = &uac->p_prm;
828 	else
829 		prm = &uac->c_prm;
830 
831 	spin_lock_irqsave(&prm->lock, flags);
832 	val = clamp(val, prm->volume_min, prm->volume_max);
833 	if (prm->volume != val) {
834 		prm->volume = val;
835 		change = 1;
836 	}
837 	spin_unlock_irqrestore(&prm->lock, flags);
838 
839 	if (change)
840 		snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
841 				&prm->snd_kctl_volume_id);
842 
843 	return 0;
844 }
845 EXPORT_SYMBOL_GPL(u_audio_set_volume);
846 
847 int u_audio_get_mute(struct g_audio *audio_dev, int playback, int *val)
848 {
849 	struct snd_uac_chip *uac = audio_dev->uac;
850 	struct uac_rtd_params *prm;
851 	unsigned long flags;
852 
853 	if (playback)
854 		prm = &uac->p_prm;
855 	else
856 		prm = &uac->c_prm;
857 
858 	spin_lock_irqsave(&prm->lock, flags);
859 	*val = prm->mute;
860 	spin_unlock_irqrestore(&prm->lock, flags);
861 
862 	return 0;
863 }
864 EXPORT_SYMBOL_GPL(u_audio_get_mute);
865 
866 int u_audio_set_mute(struct g_audio *audio_dev, int playback, int val)
867 {
868 	struct snd_uac_chip *uac = audio_dev->uac;
869 	struct uac_rtd_params *prm;
870 	unsigned long flags;
871 	int change = 0;
872 	int mute;
873 
874 	if (playback)
875 		prm = &uac->p_prm;
876 	else
877 		prm = &uac->c_prm;
878 
879 	mute = val ? 1 : 0;
880 
881 	spin_lock_irqsave(&prm->lock, flags);
882 	if (prm->mute != mute) {
883 		prm->mute = mute;
884 		change = 1;
885 	}
886 	spin_unlock_irqrestore(&prm->lock, flags);
887 
888 	if (change)
889 		snd_ctl_notify(uac->card, SNDRV_CTL_EVENT_MASK_VALUE,
890 			       &prm->snd_kctl_mute_id);
891 
892 	return 0;
893 }
894 EXPORT_SYMBOL_GPL(u_audio_set_mute);
895 
896 
897 static int u_audio_pitch_info(struct snd_kcontrol *kcontrol,
898 				   struct snd_ctl_elem_info *uinfo)
899 {
900 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
901 	struct snd_uac_chip *uac = prm->uac;
902 	struct g_audio *audio_dev = uac->audio_dev;
903 	struct uac_params *params = &audio_dev->params;
904 	unsigned int pitch_min, pitch_max;
905 
906 	pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
907 	pitch_max = (1000 + params->fb_max) * 1000;
908 
909 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
910 	uinfo->count = 1;
911 	uinfo->value.integer.min = pitch_min;
912 	uinfo->value.integer.max = pitch_max;
913 	uinfo->value.integer.step = 1;
914 	return 0;
915 }
916 
917 static int u_audio_pitch_get(struct snd_kcontrol *kcontrol,
918 				   struct snd_ctl_elem_value *ucontrol)
919 {
920 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
921 
922 	ucontrol->value.integer.value[0] = prm->pitch;
923 
924 	return 0;
925 }
926 
927 static int u_audio_pitch_put(struct snd_kcontrol *kcontrol,
928 				  struct snd_ctl_elem_value *ucontrol)
929 {
930 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
931 	struct snd_uac_chip *uac = prm->uac;
932 	struct g_audio *audio_dev = uac->audio_dev;
933 	struct uac_params *params = &audio_dev->params;
934 	unsigned int val;
935 	unsigned int pitch_min, pitch_max;
936 	int change = 0;
937 
938 	pitch_min = (1000 - FBACK_SLOW_MAX) * 1000;
939 	pitch_max = (1000 + params->fb_max) * 1000;
940 
941 	val = ucontrol->value.integer.value[0];
942 
943 	if (val < pitch_min)
944 		val = pitch_min;
945 	if (val > pitch_max)
946 		val = pitch_max;
947 
948 	if (prm->pitch != val) {
949 		prm->pitch = val;
950 		change = 1;
951 	}
952 
953 	return change;
954 }
955 
956 static int u_audio_mute_info(struct snd_kcontrol *kcontrol,
957 				   struct snd_ctl_elem_info *uinfo)
958 {
959 	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
960 	uinfo->count = 1;
961 	uinfo->value.integer.min = 0;
962 	uinfo->value.integer.max = 1;
963 	uinfo->value.integer.step = 1;
964 
965 	return 0;
966 }
967 
968 static int u_audio_mute_get(struct snd_kcontrol *kcontrol,
969 				   struct snd_ctl_elem_value *ucontrol)
970 {
971 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
972 	unsigned long flags;
973 
974 	spin_lock_irqsave(&prm->lock, flags);
975 	ucontrol->value.integer.value[0] = !prm->mute;
976 	spin_unlock_irqrestore(&prm->lock, flags);
977 
978 	return 0;
979 }
980 
981 static int u_audio_mute_put(struct snd_kcontrol *kcontrol,
982 				  struct snd_ctl_elem_value *ucontrol)
983 {
984 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
985 	struct snd_uac_chip *uac = prm->uac;
986 	struct g_audio *audio_dev = uac->audio_dev;
987 	unsigned int val;
988 	unsigned long flags;
989 	int change = 0;
990 
991 	val = !ucontrol->value.integer.value[0];
992 
993 	spin_lock_irqsave(&prm->lock, flags);
994 	if (val != prm->mute) {
995 		prm->mute = val;
996 		change = 1;
997 	}
998 	spin_unlock_irqrestore(&prm->lock, flags);
999 
1000 	if (change && audio_dev->notify)
1001 		audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_MUTE);
1002 
1003 	return change;
1004 }
1005 
1006 /*
1007  * TLV callback for mixer volume controls
1008  */
1009 static int u_audio_volume_tlv(struct snd_kcontrol *kcontrol, int op_flag,
1010 			 unsigned int size, unsigned int __user *_tlv)
1011 {
1012 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1013 	DECLARE_TLV_DB_MINMAX(scale, 0, 0);
1014 
1015 	if (size < sizeof(scale))
1016 		return -ENOMEM;
1017 
1018 	/* UAC volume resolution is 1/256 dB, TLV is 1/100 dB */
1019 	scale[2] = (prm->volume_min * 100) / 256;
1020 	scale[3] = (prm->volume_max * 100) / 256;
1021 	if (copy_to_user(_tlv, scale, sizeof(scale)))
1022 		return -EFAULT;
1023 
1024 	return 0;
1025 }
1026 
1027 static int u_audio_volume_info(struct snd_kcontrol *kcontrol,
1028 				   struct snd_ctl_elem_info *uinfo)
1029 {
1030 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1031 
1032 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1033 	uinfo->count = 1;
1034 	uinfo->value.integer.min = 0;
1035 	uinfo->value.integer.max =
1036 		(prm->volume_max - prm->volume_min + prm->volume_res - 1)
1037 		/ prm->volume_res;
1038 	uinfo->value.integer.step = 1;
1039 
1040 	return 0;
1041 }
1042 
1043 static int u_audio_volume_get(struct snd_kcontrol *kcontrol,
1044 				   struct snd_ctl_elem_value *ucontrol)
1045 {
1046 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1047 	unsigned long flags;
1048 
1049 	spin_lock_irqsave(&prm->lock, flags);
1050 	ucontrol->value.integer.value[0] =
1051 			(prm->volume - prm->volume_min) / prm->volume_res;
1052 	spin_unlock_irqrestore(&prm->lock, flags);
1053 
1054 	return 0;
1055 }
1056 
1057 static int u_audio_volume_put(struct snd_kcontrol *kcontrol,
1058 				  struct snd_ctl_elem_value *ucontrol)
1059 {
1060 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1061 	struct snd_uac_chip *uac = prm->uac;
1062 	struct g_audio *audio_dev = uac->audio_dev;
1063 	unsigned int val;
1064 	s16 volume;
1065 	unsigned long flags;
1066 	int change = 0;
1067 
1068 	val = ucontrol->value.integer.value[0];
1069 
1070 	spin_lock_irqsave(&prm->lock, flags);
1071 	volume = (val * prm->volume_res) + prm->volume_min;
1072 	volume = clamp(volume, prm->volume_min, prm->volume_max);
1073 	if (volume != prm->volume) {
1074 		prm->volume = volume;
1075 		change = 1;
1076 	}
1077 	spin_unlock_irqrestore(&prm->lock, flags);
1078 
1079 	if (change && audio_dev->notify)
1080 		audio_dev->notify(audio_dev, prm->fu_id, UAC_FU_VOLUME);
1081 
1082 	return change;
1083 }
1084 
1085 static int get_max_srate(const int *srates)
1086 {
1087 	int i, max_srate = 0;
1088 
1089 	for (i = 0; i < UAC_MAX_RATES; i++) {
1090 		if (srates[i] == 0)
1091 			break;
1092 		if (srates[i] > max_srate)
1093 			max_srate = srates[i];
1094 	}
1095 	return max_srate;
1096 }
1097 
1098 static int get_min_srate(const int *srates)
1099 {
1100 	int i, min_srate = INT_MAX;
1101 
1102 	for (i = 0; i < UAC_MAX_RATES; i++) {
1103 		if (srates[i] == 0)
1104 			break;
1105 		if (srates[i] < min_srate)
1106 			min_srate = srates[i];
1107 	}
1108 	return min_srate;
1109 }
1110 
1111 static int u_audio_rate_info(struct snd_kcontrol *kcontrol,
1112 				struct snd_ctl_elem_info *uinfo)
1113 {
1114 	const int *srates;
1115 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1116 	struct snd_uac_chip *uac = prm->uac;
1117 	struct g_audio *audio_dev = uac->audio_dev;
1118 	struct uac_params *params = &audio_dev->params;
1119 
1120 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
1121 	uinfo->count = 1;
1122 
1123 	if (prm == &uac->c_prm)
1124 		srates = params->c_srates;
1125 	else
1126 		srates = params->p_srates;
1127 	uinfo->value.integer.min = get_min_srate(srates);
1128 	uinfo->value.integer.max = get_max_srate(srates);
1129 	return 0;
1130 }
1131 
1132 static int u_audio_rate_get(struct snd_kcontrol *kcontrol,
1133 						 struct snd_ctl_elem_value *ucontrol)
1134 {
1135 	struct uac_rtd_params *prm = snd_kcontrol_chip(kcontrol);
1136 	unsigned long flags;
1137 
1138 	spin_lock_irqsave(&prm->lock, flags);
1139 	if (prm->active)
1140 		ucontrol->value.integer.value[0] = prm->srate;
1141 	else
1142 		/* not active: reporting zero rate */
1143 		ucontrol->value.integer.value[0] = 0;
1144 	spin_unlock_irqrestore(&prm->lock, flags);
1145 	return 0;
1146 }
1147 
1148 static struct snd_kcontrol_new u_audio_controls[]  = {
1149 	[UAC_FBACK_CTRL] = {
1150     .iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1151     .name =         "Capture Pitch 1000000",
1152     .info =         u_audio_pitch_info,
1153     .get =          u_audio_pitch_get,
1154     .put =          u_audio_pitch_put,
1155   },
1156 	[UAC_P_PITCH_CTRL] = {
1157 		.iface =        SNDRV_CTL_ELEM_IFACE_PCM,
1158 		.name =         "Playback Pitch 1000000",
1159 		.info =         u_audio_pitch_info,
1160 		.get =          u_audio_pitch_get,
1161 		.put =          u_audio_pitch_put,
1162 	},
1163 	[UAC_MUTE_CTRL] = {
1164 		.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
1165 		.name =		"", /* will be filled later */
1166 		.info =		u_audio_mute_info,
1167 		.get =		u_audio_mute_get,
1168 		.put =		u_audio_mute_put,
1169 	},
1170 	[UAC_VOLUME_CTRL] = {
1171 		.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
1172 		.name =		"", /* will be filled later */
1173 		.info =		u_audio_volume_info,
1174 		.get =		u_audio_volume_get,
1175 		.put =		u_audio_volume_put,
1176 	},
1177 	[UAC_RATE_CTRL] = {
1178 		.iface =	SNDRV_CTL_ELEM_IFACE_PCM,
1179 		.name =		"", /* will be filled later */
1180 		.access =	SNDRV_CTL_ELEM_ACCESS_READ | SNDRV_CTL_ELEM_ACCESS_VOLATILE,
1181 		.info =		u_audio_rate_info,
1182 		.get =		u_audio_rate_get,
1183 	},
1184 };
1185 
1186 static void u_audio_card_free(struct snd_card *card)
1187 {
1188 	struct snd_uac_chip *uac = card->private_data;
1189 
1190 	if (!uac)
1191 		return;
1192 
1193 	kfree(uac->p_prm.reqs);
1194 	kfree(uac->c_prm.reqs);
1195 	kfree(uac->p_prm.rbuf);
1196 	kfree(uac->c_prm.rbuf);
1197 	kfree(uac);
1198 }
1199 
1200 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
1201 					const char *card_name)
1202 {
1203 	struct snd_uac_chip *uac;
1204 	struct snd_card *card;
1205 	struct snd_pcm *pcm;
1206 	struct snd_kcontrol *kctl;
1207 	struct uac_params *params;
1208 	int p_chmask, c_chmask;
1209 	int i, err;
1210 
1211 	if (!g_audio)
1212 		return -EINVAL;
1213 
1214 	uac = kzalloc_obj(*uac);
1215 	if (!uac)
1216 		return -ENOMEM;
1217 	g_audio->uac = uac;
1218 	uac->audio_dev = g_audio;
1219 
1220 	params = &g_audio->params;
1221 	p_chmask = params->p_chmask;
1222 	c_chmask = params->c_chmask;
1223 
1224 	if (c_chmask) {
1225 		struct uac_rtd_params *prm = &uac->c_prm;
1226 
1227 		spin_lock_init(&prm->lock);
1228 		uac->c_prm.uac = uac;
1229 		prm->max_psize = g_audio->out_ep_maxpsize;
1230 		prm->srate = params->c_srates[0];
1231 
1232 		prm->reqs = kzalloc_objs(struct usb_request *,
1233 					 params->req_number);
1234 		if (!prm->reqs) {
1235 			err = -ENOMEM;
1236 			goto fail;
1237 		}
1238 
1239 		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
1240 				GFP_KERNEL);
1241 		if (!prm->rbuf) {
1242 			prm->max_psize = 0;
1243 			err = -ENOMEM;
1244 			goto fail;
1245 		}
1246 	}
1247 
1248 	if (p_chmask) {
1249 		struct uac_rtd_params *prm = &uac->p_prm;
1250 
1251 		spin_lock_init(&prm->lock);
1252 		uac->p_prm.uac = uac;
1253 		prm->max_psize = g_audio->in_ep_maxpsize;
1254 		prm->srate = params->p_srates[0];
1255 
1256 		prm->reqs = kzalloc_objs(struct usb_request *,
1257 					 params->req_number);
1258 		if (!prm->reqs) {
1259 			err = -ENOMEM;
1260 			goto fail;
1261 		}
1262 
1263 		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
1264 				GFP_KERNEL);
1265 		if (!prm->rbuf) {
1266 			prm->max_psize = 0;
1267 			err = -ENOMEM;
1268 			goto fail;
1269 		}
1270 	}
1271 
1272 	/* Choose any slot, with no id */
1273 	err = snd_card_new(&g_audio->gadget->dev,
1274 			-1, NULL, THIS_MODULE, 0, &card);
1275 	if (err < 0)
1276 		goto fail;
1277 
1278 	uac->card = card;
1279 	card->private_data = uac;
1280 	card->private_free = u_audio_card_free;
1281 
1282 	/*
1283 	 * Create first PCM device
1284 	 * Create a substream only for non-zero channel streams
1285 	 */
1286 	err = snd_pcm_new(uac->card, pcm_name, 0,
1287 			       p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
1288 	if (err < 0)
1289 		goto snd_fail;
1290 
1291 	strscpy(pcm->name, pcm_name);
1292 	pcm->private_data = uac;
1293 	uac->pcm = pcm;
1294 
1295 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
1296 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
1297 
1298 	/*
1299 	 * Create mixer and controls
1300 	 * Create only if it's required on USB side
1301 	 */
1302 	if ((c_chmask && g_audio->in_ep_fback)
1303 			|| (p_chmask && params->p_fu.id)
1304 			|| (c_chmask && params->c_fu.id))
1305 		strscpy(card->mixername, card_name);
1306 
1307 	if (c_chmask && g_audio->in_ep_fback) {
1308 		kctl = snd_ctl_new1(&u_audio_controls[UAC_FBACK_CTRL],
1309 				    &uac->c_prm);
1310 		if (!kctl) {
1311 			err = -ENOMEM;
1312 			goto snd_fail;
1313 		}
1314 
1315 		kctl->id.device = pcm->device;
1316 		kctl->id.subdevice = 0;
1317 
1318 		err = snd_ctl_add(card, kctl);
1319 		if (err < 0)
1320 			goto snd_fail;
1321 	}
1322 
1323 	if (p_chmask) {
1324 		kctl = snd_ctl_new1(&u_audio_controls[UAC_P_PITCH_CTRL],
1325 				    &uac->p_prm);
1326 		if (!kctl) {
1327 			err = -ENOMEM;
1328 			goto snd_fail;
1329 		}
1330 
1331 		kctl->id.device = pcm->device;
1332 		kctl->id.subdevice = 0;
1333 
1334 		err = snd_ctl_add(card, kctl);
1335 		if (err < 0)
1336 			goto snd_fail;
1337 	}
1338 
1339 	for (i = 0; i <= SNDRV_PCM_STREAM_LAST; i++) {
1340 		struct uac_rtd_params *prm;
1341 		struct uac_fu_params *fu;
1342 		char ctrl_name[24];
1343 		char *direction;
1344 
1345 		if (!pcm->streams[i].substream_count)
1346 			continue;
1347 
1348 		if (i == SNDRV_PCM_STREAM_PLAYBACK) {
1349 			prm = &uac->p_prm;
1350 			fu = &params->p_fu;
1351 			direction = "Playback";
1352 		} else {
1353 			prm = &uac->c_prm;
1354 			fu = &params->c_fu;
1355 			direction = "Capture";
1356 		}
1357 
1358 		prm->fu_id = fu->id;
1359 
1360 		if (fu->mute_present) {
1361 			snprintf(ctrl_name, sizeof(ctrl_name),
1362 					"PCM %s Switch", direction);
1363 
1364 			u_audio_controls[UAC_MUTE_CTRL].name = ctrl_name;
1365 
1366 			kctl = snd_ctl_new1(&u_audio_controls[UAC_MUTE_CTRL],
1367 					    prm);
1368 			if (!kctl) {
1369 				err = -ENOMEM;
1370 				goto snd_fail;
1371 			}
1372 
1373 			kctl->id.device = pcm->device;
1374 			kctl->id.subdevice = 0;
1375 
1376 			err = snd_ctl_add(card, kctl);
1377 			if (err < 0)
1378 				goto snd_fail;
1379 			prm->snd_kctl_mute_id = kctl->id;
1380 			prm->mute = 0;
1381 		}
1382 
1383 		if (fu->volume_present) {
1384 			snprintf(ctrl_name, sizeof(ctrl_name),
1385 					"PCM %s Volume", direction);
1386 
1387 			u_audio_controls[UAC_VOLUME_CTRL].name = ctrl_name;
1388 
1389 			kctl = snd_ctl_new1(&u_audio_controls[UAC_VOLUME_CTRL],
1390 					    prm);
1391 			if (!kctl) {
1392 				err = -ENOMEM;
1393 				goto snd_fail;
1394 			}
1395 
1396 			kctl->id.device = pcm->device;
1397 			kctl->id.subdevice = 0;
1398 
1399 
1400 			kctl->tlv.c = u_audio_volume_tlv;
1401 			kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ |
1402 					SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1403 
1404 			err = snd_ctl_add(card, kctl);
1405 			if (err < 0)
1406 				goto snd_fail;
1407 			prm->snd_kctl_volume_id = kctl->id;
1408 			prm->volume = fu->volume_max;
1409 			prm->volume_max = fu->volume_max;
1410 			prm->volume_min = fu->volume_min;
1411 			prm->volume_res = fu->volume_res;
1412 		}
1413 
1414 		/* Add rate control */
1415 		snprintf(ctrl_name, sizeof(ctrl_name),
1416 				"%s Rate", direction);
1417 		u_audio_controls[UAC_RATE_CTRL].name = ctrl_name;
1418 
1419 		kctl = snd_ctl_new1(&u_audio_controls[UAC_RATE_CTRL], prm);
1420 		if (!kctl) {
1421 			err = -ENOMEM;
1422 			goto snd_fail;
1423 		}
1424 
1425 		kctl->id.device = pcm->device;
1426 		kctl->id.subdevice = 0;
1427 
1428 		err = snd_ctl_add(card, kctl);
1429 		if (err < 0)
1430 			goto snd_fail;
1431 		prm->snd_kctl_rate_id = kctl->id;
1432 	}
1433 
1434 	strscpy(card->driver, card_name);
1435 	strscpy(card->shortname, card_name);
1436 	snprintf(card->longname, sizeof(card->longname), "%s %i",
1437 		 card_name, card->dev->id);
1438 
1439 	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
1440 				       NULL, 0, BUFF_SIZE_MAX);
1441 
1442 	err = snd_card_register(card);
1443 
1444 	if (!err)
1445 		return 0;
1446 
1447 snd_fail:
1448 	snd_card_free(card);
1449 	return err;
1450 
1451 fail:
1452 	kfree(uac->p_prm.reqs);
1453 	kfree(uac->c_prm.reqs);
1454 	kfree(uac->p_prm.rbuf);
1455 	kfree(uac->c_prm.rbuf);
1456 	kfree(uac);
1457 
1458 	return err;
1459 }
1460 EXPORT_SYMBOL_GPL(g_audio_setup);
1461 
1462 void g_audio_cleanup(struct g_audio *g_audio)
1463 {
1464 	struct snd_uac_chip *uac;
1465 	struct snd_card *card;
1466 
1467 	if (!g_audio || !g_audio->uac)
1468 		return;
1469 
1470 	uac = g_audio->uac;
1471 	g_audio->uac = NULL;
1472 
1473 	card = uac->card;
1474 	if (card)
1475 		snd_card_free_when_closed(card);
1476 }
1477 EXPORT_SYMBOL_GPL(g_audio_cleanup);
1478 
1479 MODULE_LICENSE("GPL");
1480 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
1481 MODULE_AUTHOR("Ruslan Bilovol");
1482