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