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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/module.h>
16#include <sound/core.h>
17#include <sound/pcm.h>
18#include <sound/pcm_params.h>
19
20#include "u_audio.h"
21
22#define BUFF_SIZE_MAX (PAGE_SIZE * 16)
23#define PRD_SIZE_MAX PAGE_SIZE
24#define MIN_PERIODS 4
25
26struct uac_req {
27 struct uac_rtd_params *pp; /* parent param */
28 struct usb_request *req;
29};
30
31/* Runtime data params for one stream */
32struct uac_rtd_params {
33 struct snd_uac_chip *uac; /* parent chip */
34 bool ep_enabled; /* if the ep is enabled */
35
36 struct snd_pcm_substream *ss;
37
38 /* Ring buffer */
39 ssize_t hw_ptr;
40
41 void *rbuf;
42
43 unsigned int max_psize; /* MaxPacketSize of endpoint */
44 struct uac_req *ureq;
45
46 spinlock_t lock;
47};
48
49struct snd_uac_chip {
50 struct g_audio *audio_dev;
51
52 struct uac_rtd_params p_prm;
53 struct uac_rtd_params c_prm;
54
55 struct snd_card *card;
56 struct snd_pcm *pcm;
57
58 /* timekeeping for the playback endpoint */
59 unsigned int p_interval;
60 unsigned int p_residue;
61
62 /* pre-calculated values for playback iso completion */
63 unsigned int p_pktsize;
64 unsigned int p_pktsize_residue;
65 unsigned int p_framesize;
66};
67
68static const struct snd_pcm_hardware uac_pcm_hardware = {
69 .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
70 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
71 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
72 .rates = SNDRV_PCM_RATE_CONTINUOUS,
73 .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
74 .buffer_bytes_max = BUFF_SIZE_MAX,
75 .period_bytes_max = PRD_SIZE_MAX,
76 .periods_min = MIN_PERIODS,
77};
78
79static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
80{
81 unsigned int pending;
82 unsigned long flags, flags2;
83 unsigned int hw_ptr;
84 int status = req->status;
85 struct uac_req *ur = req->context;
86 struct snd_pcm_substream *substream;
87 struct snd_pcm_runtime *runtime;
88 struct uac_rtd_params *prm = ur->pp;
89 struct snd_uac_chip *uac = prm->uac;
90
91 /* i/f shutting down */
92 if (!prm->ep_enabled || req->status == -ESHUTDOWN)
93 return;
94
95 /*
96 * We can't really do much about bad xfers.
97 * Afterall, the ISOCH xfers could fail legitimately.
98 */
99 if (status)
100 pr_debug("%s: iso_complete status(%d) %d/%d\n",
101 __func__, status, req->actual, req->length);
102
103 substream = prm->ss;
104
105 /* Do nothing if ALSA isn't active */
106 if (!substream)
107 goto exit;
108
109 snd_pcm_stream_lock_irqsave(substream, flags2);
110
111 runtime = substream->runtime;
112 if (!runtime || !snd_pcm_running(substream)) {
113 snd_pcm_stream_unlock_irqrestore(substream, flags2);
114 goto exit;
115 }
116
117 spin_lock_irqsave(&prm->lock, flags);
118
119 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
120 /*
121 * For each IN packet, take the quotient of the current data
122 * rate and the endpoint's interval as the base packet size.
123 * If there is a residue from this division, add it to the
124 * residue accumulator.
125 */
126 req->length = uac->p_pktsize;
127 uac->p_residue += uac->p_pktsize_residue;
128
129 /*
130 * Whenever there are more bytes in the accumulator than we
131 * need to add one more sample frame, increase this packet's
132 * size and decrease the accumulator.
133 */
134 if (uac->p_residue / uac->p_interval >= uac->p_framesize) {
135 req->length += uac->p_framesize;
136 uac->p_residue -= uac->p_framesize *
137 uac->p_interval;
138 }
139
140 req->actual = req->length;
141 }
142
143 hw_ptr = prm->hw_ptr;
144
145 spin_unlock_irqrestore(&prm->lock, flags);
146
147 /* Pack USB load in ALSA ring buffer */
148 pending = runtime->dma_bytes - hw_ptr;
149
150 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
151 if (unlikely(pending < req->actual)) {
152 memcpy(req->buf, runtime->dma_area + hw_ptr, pending);
153 memcpy(req->buf + pending, runtime->dma_area,
154 req->actual - pending);
155 } else {
156 memcpy(req->buf, runtime->dma_area + hw_ptr,
157 req->actual);
158 }
159 } else {
160 if (unlikely(pending < req->actual)) {
161 memcpy(runtime->dma_area + hw_ptr, req->buf, pending);
162 memcpy(runtime->dma_area, req->buf + pending,
163 req->actual - pending);
164 } else {
165 memcpy(runtime->dma_area + hw_ptr, req->buf,
166 req->actual);
167 }
168 }
169
170 spin_lock_irqsave(&prm->lock, flags);
171 /* update hw_ptr after data is copied to memory */
172 prm->hw_ptr = (hw_ptr + req->actual) % runtime->dma_bytes;
173 hw_ptr = prm->hw_ptr;
174 spin_unlock_irqrestore(&prm->lock, flags);
175 snd_pcm_stream_unlock_irqrestore(substream, flags2);
176
177 if ((hw_ptr % snd_pcm_lib_period_bytes(substream)) < req->actual)
178 snd_pcm_period_elapsed(substream);
179
180exit:
181 if (usb_ep_queue(ep, req, GFP_ATOMIC))
182 dev_err(uac->card->dev, "%d Error!\n", __LINE__);
183}
184
185static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
186{
187 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
188 struct uac_rtd_params *prm;
189 struct g_audio *audio_dev;
190 struct uac_params *params;
191 unsigned long flags;
192 int err = 0;
193
194 audio_dev = uac->audio_dev;
195 params = &audio_dev->params;
196
197 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
198 prm = &uac->p_prm;
199 else
200 prm = &uac->c_prm;
201
202 spin_lock_irqsave(&prm->lock, flags);
203
204 /* Reset */
205 prm->hw_ptr = 0;
206
207 switch (cmd) {
208 case SNDRV_PCM_TRIGGER_START:
209 case SNDRV_PCM_TRIGGER_RESUME:
210 prm->ss = substream;
211 break;
212 case SNDRV_PCM_TRIGGER_STOP:
213 case SNDRV_PCM_TRIGGER_SUSPEND:
214 prm->ss = NULL;
215 break;
216 default:
217 err = -EINVAL;
218 }
219
220 spin_unlock_irqrestore(&prm->lock, flags);
221
222 /* Clear buffer after Play stops */
223 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
224 memset(prm->rbuf, 0, prm->max_psize * params->req_number);
225
226 return err;
227}
228
229static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
230{
231 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
232 struct uac_rtd_params *prm;
233
234 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
235 prm = &uac->p_prm;
236 else
237 prm = &uac->c_prm;
238
239 return bytes_to_frames(substream->runtime, prm->hw_ptr);
240}
241
242static int uac_pcm_hw_params(struct snd_pcm_substream *substream,
243 struct snd_pcm_hw_params *hw_params)
244{
245 return snd_pcm_lib_malloc_pages(substream,
246 params_buffer_bytes(hw_params));
247}
248
249static int uac_pcm_hw_free(struct snd_pcm_substream *substream)
250{
251 return snd_pcm_lib_free_pages(substream);
252}
253
254static int uac_pcm_open(struct snd_pcm_substream *substream)
255{
256 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
257 struct snd_pcm_runtime *runtime = substream->runtime;
258 struct g_audio *audio_dev;
259 struct uac_params *params;
260 int p_ssize, c_ssize;
261 int p_srate, c_srate;
262 int p_chmask, c_chmask;
263
264 audio_dev = uac->audio_dev;
265 params = &audio_dev->params;
266 p_ssize = params->p_ssize;
267 c_ssize = params->c_ssize;
268 p_srate = params->p_srate;
269 c_srate = params->c_srate;
270 p_chmask = params->p_chmask;
271 c_chmask = params->c_chmask;
272 uac->p_residue = 0;
273
274 runtime->hw = uac_pcm_hardware;
275
276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
277 spin_lock_init(&uac->p_prm.lock);
278 runtime->hw.rate_min = p_srate;
279 switch (p_ssize) {
280 case 3:
281 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
282 break;
283 case 4:
284 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
285 break;
286 default:
287 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
288 break;
289 }
290 runtime->hw.channels_min = num_channels(p_chmask);
291 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
292 / runtime->hw.periods_min;
293 } else {
294 spin_lock_init(&uac->c_prm.lock);
295 runtime->hw.rate_min = c_srate;
296 switch (c_ssize) {
297 case 3:
298 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
299 break;
300 case 4:
301 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
302 break;
303 default:
304 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
305 break;
306 }
307 runtime->hw.channels_min = num_channels(c_chmask);
308 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
309 / runtime->hw.periods_min;
310 }
311
312 runtime->hw.rate_max = runtime->hw.rate_min;
313 runtime->hw.channels_max = runtime->hw.channels_min;
314
315 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
316
317 return 0;
318}
319
320/* ALSA cries without these function pointers */
321static int uac_pcm_null(struct snd_pcm_substream *substream)
322{
323 return 0;
324}
325
326static const struct snd_pcm_ops uac_pcm_ops = {
327 .open = uac_pcm_open,
328 .close = uac_pcm_null,
329 .ioctl = snd_pcm_lib_ioctl,
330 .hw_params = uac_pcm_hw_params,
331 .hw_free = uac_pcm_hw_free,
332 .trigger = uac_pcm_trigger,
333 .pointer = uac_pcm_pointer,
334 .prepare = uac_pcm_null,
335};
336
337static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
338{
339 struct snd_uac_chip *uac = prm->uac;
340 struct g_audio *audio_dev;
341 struct uac_params *params;
342 int i;
343
344 if (!prm->ep_enabled)
345 return;
346
347 prm->ep_enabled = false;
348
349 audio_dev = uac->audio_dev;
350 params = &audio_dev->params;
351
352 for (i = 0; i < params->req_number; i++) {
353 if (prm->ureq[i].req) {
354 usb_ep_dequeue(ep, prm->ureq[i].req);
355 usb_ep_free_request(ep, prm->ureq[i].req);
356 prm->ureq[i].req = NULL;
357 }
358 }
359
360 if (usb_ep_disable(ep))
361 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
362}
363
364
365int u_audio_start_capture(struct g_audio *audio_dev)
366{
367 struct snd_uac_chip *uac = audio_dev->uac;
368 struct usb_gadget *gadget = audio_dev->gadget;
369 struct device *dev = &gadget->dev;
370 struct usb_request *req;
371 struct usb_ep *ep;
372 struct uac_rtd_params *prm;
373 struct uac_params *params = &audio_dev->params;
374 int req_len, i;
375
376 ep = audio_dev->out_ep;
377 prm = &uac->c_prm;
378 config_ep_by_speed(gadget, &audio_dev->func, ep);
379 req_len = prm->max_psize;
380
381 prm->ep_enabled = true;
382 usb_ep_enable(ep);
383
384 for (i = 0; i < params->req_number; i++) {
385 if (!prm->ureq[i].req) {
386 req = usb_ep_alloc_request(ep, GFP_ATOMIC);
387 if (req == NULL)
388 return -ENOMEM;
389
390 prm->ureq[i].req = req;
391 prm->ureq[i].pp = prm;
392
393 req->zero = 0;
394 req->context = &prm->ureq[i];
395 req->length = req_len;
396 req->complete = u_audio_iso_complete;
397 req->buf = prm->rbuf + i * prm->max_psize;
398 }
399
400 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
401 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
402 }
403
404 return 0;
405}
406EXPORT_SYMBOL_GPL(u_audio_start_capture);
407
408void u_audio_stop_capture(struct g_audio *audio_dev)
409{
410 struct snd_uac_chip *uac = audio_dev->uac;
411
412 free_ep(&uac->c_prm, audio_dev->out_ep);
413}
414EXPORT_SYMBOL_GPL(u_audio_stop_capture);
415
416int u_audio_start_playback(struct g_audio *audio_dev)
417{
418 struct snd_uac_chip *uac = audio_dev->uac;
419 struct usb_gadget *gadget = audio_dev->gadget;
420 struct device *dev = &gadget->dev;
421 struct usb_request *req;
422 struct usb_ep *ep;
423 struct uac_rtd_params *prm;
424 struct uac_params *params = &audio_dev->params;
425 unsigned int factor, rate;
426 const struct usb_endpoint_descriptor *ep_desc;
427 int req_len, i;
428
429 ep = audio_dev->in_ep;
430 prm = &uac->p_prm;
431 config_ep_by_speed(gadget, &audio_dev->func, ep);
432
433 ep_desc = ep->desc;
434
435 /* pre-calculate the playback endpoint's interval */
436 if (gadget->speed == USB_SPEED_FULL)
437 factor = 1000;
438 else
439 factor = 8000;
440
441 /* pre-compute some values for iso_complete() */
442 uac->p_framesize = params->p_ssize *
443 num_channels(params->p_chmask);
444 rate = params->p_srate * uac->p_framesize;
445 uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
446 uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval,
447 prm->max_psize);
448
449 if (uac->p_pktsize < prm->max_psize)
450 uac->p_pktsize_residue = rate % uac->p_interval;
451 else
452 uac->p_pktsize_residue = 0;
453
454 req_len = uac->p_pktsize;
455 uac->p_residue = 0;
456
457 prm->ep_enabled = true;
458 usb_ep_enable(ep);
459
460 for (i = 0; i < params->req_number; i++) {
461 if (!prm->ureq[i].req) {
462 req = usb_ep_alloc_request(ep, GFP_ATOMIC);
463 if (req == NULL)
464 return -ENOMEM;
465
466 prm->ureq[i].req = req;
467 prm->ureq[i].pp = prm;
468
469 req->zero = 0;
470 req->context = &prm->ureq[i];
471 req->length = req_len;
472 req->complete = u_audio_iso_complete;
473 req->buf = prm->rbuf + i * prm->max_psize;
474 }
475
476 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
477 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
478 }
479
480 return 0;
481}
482EXPORT_SYMBOL_GPL(u_audio_start_playback);
483
484void u_audio_stop_playback(struct g_audio *audio_dev)
485{
486 struct snd_uac_chip *uac = audio_dev->uac;
487
488 free_ep(&uac->p_prm, audio_dev->in_ep);
489}
490EXPORT_SYMBOL_GPL(u_audio_stop_playback);
491
492int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
493 const char *card_name)
494{
495 struct snd_uac_chip *uac;
496 struct snd_card *card;
497 struct snd_pcm *pcm;
498 struct uac_params *params;
499 int p_chmask, c_chmask;
500 int err;
501
502 if (!g_audio)
503 return -EINVAL;
504
505 uac = kzalloc(sizeof(*uac), GFP_KERNEL);
506 if (!uac)
507 return -ENOMEM;
508 g_audio->uac = uac;
509 uac->audio_dev = g_audio;
510
511 params = &g_audio->params;
512 p_chmask = params->p_chmask;
513 c_chmask = params->c_chmask;
514
515 if (c_chmask) {
516 struct uac_rtd_params *prm = &uac->c_prm;
517
518 uac->c_prm.uac = uac;
519 prm->max_psize = g_audio->out_ep_maxpsize;
520
521 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
522 GFP_KERNEL);
523 if (!prm->ureq) {
524 err = -ENOMEM;
525 goto fail;
526 }
527
528 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
529 GFP_KERNEL);
530 if (!prm->rbuf) {
531 prm->max_psize = 0;
532 err = -ENOMEM;
533 goto fail;
534 }
535 }
536
537 if (p_chmask) {
538 struct uac_rtd_params *prm = &uac->p_prm;
539
540 uac->p_prm.uac = uac;
541 prm->max_psize = g_audio->in_ep_maxpsize;
542
543 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
544 GFP_KERNEL);
545 if (!prm->ureq) {
546 err = -ENOMEM;
547 goto fail;
548 }
549
550 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
551 GFP_KERNEL);
552 if (!prm->rbuf) {
553 prm->max_psize = 0;
554 err = -ENOMEM;
555 goto fail;
556 }
557 }
558
559 /* Choose any slot, with no id */
560 err = snd_card_new(&g_audio->gadget->dev,
561 -1, NULL, THIS_MODULE, 0, &card);
562 if (err < 0)
563 goto fail;
564
565 uac->card = card;
566
567 /*
568 * Create first PCM device
569 * Create a substream only for non-zero channel streams
570 */
571 err = snd_pcm_new(uac->card, pcm_name, 0,
572 p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
573 if (err < 0)
574 goto snd_fail;
575
576 strlcpy(pcm->name, pcm_name, sizeof(pcm->name));
577 pcm->private_data = uac;
578 uac->pcm = pcm;
579
580 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
581 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
582
583 strlcpy(card->driver, card_name, sizeof(card->driver));
584 strlcpy(card->shortname, card_name, sizeof(card->shortname));
585 sprintf(card->longname, "%s %i", card_name, card->dev->id);
586
587 snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
588 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
589
590 err = snd_card_register(card);
591
592 if (!err)
593 return 0;
594
595snd_fail:
596 snd_card_free(card);
597fail:
598 kfree(uac->p_prm.ureq);
599 kfree(uac->c_prm.ureq);
600 kfree(uac->p_prm.rbuf);
601 kfree(uac->c_prm.rbuf);
602 kfree(uac);
603
604 return err;
605}
606EXPORT_SYMBOL_GPL(g_audio_setup);
607
608void g_audio_cleanup(struct g_audio *g_audio)
609{
610 struct snd_uac_chip *uac;
611 struct snd_card *card;
612
613 if (!g_audio || !g_audio->uac)
614 return;
615
616 uac = g_audio->uac;
617 card = uac->card;
618 if (card)
619 snd_card_free(card);
620
621 kfree(uac->p_prm.ureq);
622 kfree(uac->c_prm.ureq);
623 kfree(uac->p_prm.rbuf);
624 kfree(uac->c_prm.rbuf);
625 kfree(uac);
626}
627EXPORT_SYMBOL_GPL(g_audio_cleanup);
628
629MODULE_LICENSE("GPL");
630MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
631MODULE_AUTHOR("Ruslan Bilovol");