1 // SPDX-License-Identifier: GPL-2.0+
3 * u_audio.c -- interface to USB gadget "ALSA sound card" utilities
6 * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
8 * Sound card implementation was cut-and-pasted with changes
9 * from f_uac2.c and has:
11 * Yadwinder Singh (yadi.brar01@gmail.com)
12 * Jaswinder Singh (jaswinder.singh@linaro.org)
15 #include <linux/module.h>
16 #include <sound/core.h>
17 #include <sound/pcm.h>
18 #include <sound/pcm_params.h>
22 #define BUFF_SIZE_MAX (PAGE_SIZE * 16)
23 #define PRD_SIZE_MAX PAGE_SIZE
27 struct uac_rtd_params *pp; /* parent param */
28 struct usb_request *req;
31 /* Runtime data params for one stream */
32 struct uac_rtd_params {
33 struct snd_uac_chip *uac; /* parent chip */
34 bool ep_enabled; /* if the ep is enabled */
35 /* Size of the ring buffer */
37 unsigned char *dma_area;
39 struct snd_pcm_substream *ss;
48 unsigned max_psize; /* MaxPacketSize of endpoint */
55 struct g_audio *audio_dev;
57 struct uac_rtd_params p_prm;
58 struct uac_rtd_params c_prm;
60 struct snd_card *card;
63 /* timekeeping for the playback endpoint */
64 unsigned int p_interval;
65 unsigned int p_residue;
67 /* pre-calculated values for playback iso completion */
68 unsigned int p_pktsize;
69 unsigned int p_pktsize_residue;
70 unsigned int p_framesize;
73 static const struct snd_pcm_hardware uac_pcm_hardware = {
74 .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER
75 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID
76 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,
77 .rates = SNDRV_PCM_RATE_CONTINUOUS,
78 .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX,
79 .buffer_bytes_max = BUFF_SIZE_MAX,
80 .period_bytes_max = PRD_SIZE_MAX,
81 .periods_min = MIN_PERIODS,
84 static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)
89 bool update_alsa = false;
90 int status = req->status;
91 struct uac_req *ur = req->context;
92 struct snd_pcm_substream *substream;
93 struct uac_rtd_params *prm = ur->pp;
94 struct snd_uac_chip *uac = prm->uac;
96 /* i/f shutting down */
97 if (!prm->ep_enabled || req->status == -ESHUTDOWN)
101 * We can't really do much about bad xfers.
102 * Afterall, the ISOCH xfers could fail legitimately.
105 pr_debug("%s: iso_complete status(%d) %d/%d\n",
106 __func__, status, req->actual, req->length);
110 /* Do nothing if ALSA isn't active */
114 spin_lock_irqsave(&prm->lock, flags);
116 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
118 * For each IN packet, take the quotient of the current data
119 * rate and the endpoint's interval as the base packet size.
120 * If there is a residue from this division, add it to the
121 * residue accumulator.
123 req->length = uac->p_pktsize;
124 uac->p_residue += uac->p_pktsize_residue;
127 * Whenever there are more bytes in the accumulator than we
128 * need to add one more sample frame, increase this packet's
129 * size and decrease the accumulator.
131 if (uac->p_residue / uac->p_interval >= uac->p_framesize) {
132 req->length += uac->p_framesize;
133 uac->p_residue -= uac->p_framesize *
137 req->actual = req->length;
140 pending = prm->hw_ptr % prm->period_size;
141 pending += req->actual;
142 if (pending >= prm->period_size)
145 hw_ptr = prm->hw_ptr;
146 prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;
148 spin_unlock_irqrestore(&prm->lock, flags);
150 /* Pack USB load in ALSA ring buffer */
151 pending = prm->dma_bytes - hw_ptr;
153 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
154 if (unlikely(pending < req->actual)) {
155 memcpy(req->buf, prm->dma_area + hw_ptr, pending);
156 memcpy(req->buf + pending, prm->dma_area,
157 req->actual - pending);
159 memcpy(req->buf, prm->dma_area + hw_ptr, req->actual);
162 if (unlikely(pending < req->actual)) {
163 memcpy(prm->dma_area + hw_ptr, req->buf, pending);
164 memcpy(prm->dma_area, req->buf + pending,
165 req->actual - pending);
167 memcpy(prm->dma_area + hw_ptr, req->buf, req->actual);
172 if (usb_ep_queue(ep, req, GFP_ATOMIC))
173 dev_err(uac->card->dev, "%d Error!\n", __LINE__);
176 snd_pcm_period_elapsed(substream);
179 static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
181 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
182 struct uac_rtd_params *prm;
183 struct g_audio *audio_dev;
184 struct uac_params *params;
188 audio_dev = uac->audio_dev;
189 params = &audio_dev->params;
191 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
196 spin_lock_irqsave(&prm->lock, flags);
202 case SNDRV_PCM_TRIGGER_START:
203 case SNDRV_PCM_TRIGGER_RESUME:
206 case SNDRV_PCM_TRIGGER_STOP:
207 case SNDRV_PCM_TRIGGER_SUSPEND:
214 spin_unlock_irqrestore(&prm->lock, flags);
216 /* Clear buffer after Play stops */
217 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)
218 memset(prm->rbuf, 0, prm->max_psize * params->req_number);
223 static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)
225 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
226 struct uac_rtd_params *prm;
228 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
233 return bytes_to_frames(substream->runtime, prm->hw_ptr);
236 static int uac_pcm_hw_params(struct snd_pcm_substream *substream,
237 struct snd_pcm_hw_params *hw_params)
239 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
240 struct uac_rtd_params *prm;
243 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
248 err = snd_pcm_lib_malloc_pages(substream,
249 params_buffer_bytes(hw_params));
251 prm->dma_bytes = substream->runtime->dma_bytes;
252 prm->dma_area = substream->runtime->dma_area;
253 prm->period_size = params_period_bytes(hw_params);
259 static int uac_pcm_hw_free(struct snd_pcm_substream *substream)
261 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
262 struct uac_rtd_params *prm;
264 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
269 prm->dma_area = NULL;
271 prm->period_size = 0;
273 return snd_pcm_lib_free_pages(substream);
276 static int uac_pcm_open(struct snd_pcm_substream *substream)
278 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
279 struct snd_pcm_runtime *runtime = substream->runtime;
280 struct g_audio *audio_dev;
281 struct uac_params *params;
282 int p_ssize, c_ssize;
283 int p_srate, c_srate;
284 int p_chmask, c_chmask;
286 audio_dev = uac->audio_dev;
287 params = &audio_dev->params;
288 p_ssize = params->p_ssize;
289 c_ssize = params->c_ssize;
290 p_srate = params->p_srate;
291 c_srate = params->c_srate;
292 p_chmask = params->p_chmask;
293 c_chmask = params->c_chmask;
296 runtime->hw = uac_pcm_hardware;
298 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
299 spin_lock_init(&uac->p_prm.lock);
300 runtime->hw.rate_min = p_srate;
303 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
306 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
309 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
312 runtime->hw.channels_min = num_channels(p_chmask);
313 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
314 / runtime->hw.periods_min;
316 spin_lock_init(&uac->c_prm.lock);
317 runtime->hw.rate_min = c_srate;
320 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
323 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
326 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
329 runtime->hw.channels_min = num_channels(c_chmask);
330 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
331 / runtime->hw.periods_min;
334 runtime->hw.rate_max = runtime->hw.rate_min;
335 runtime->hw.channels_max = runtime->hw.channels_min;
337 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
342 /* ALSA cries without these function pointers */
343 static int uac_pcm_null(struct snd_pcm_substream *substream)
348 static const struct snd_pcm_ops uac_pcm_ops = {
349 .open = uac_pcm_open,
350 .close = uac_pcm_null,
351 .ioctl = snd_pcm_lib_ioctl,
352 .hw_params = uac_pcm_hw_params,
353 .hw_free = uac_pcm_hw_free,
354 .trigger = uac_pcm_trigger,
355 .pointer = uac_pcm_pointer,
356 .prepare = uac_pcm_null,
359 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
361 struct snd_uac_chip *uac = prm->uac;
362 struct g_audio *audio_dev;
363 struct uac_params *params;
366 if (!prm->ep_enabled)
369 prm->ep_enabled = false;
371 audio_dev = uac->audio_dev;
372 params = &audio_dev->params;
374 for (i = 0; i < params->req_number; i++) {
375 if (prm->ureq[i].req) {
376 usb_ep_dequeue(ep, prm->ureq[i].req);
377 usb_ep_free_request(ep, prm->ureq[i].req);
378 prm->ureq[i].req = NULL;
382 if (usb_ep_disable(ep))
383 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
387 int u_audio_start_capture(struct g_audio *audio_dev)
389 struct snd_uac_chip *uac = audio_dev->uac;
390 struct usb_gadget *gadget = audio_dev->gadget;
391 struct device *dev = &gadget->dev;
392 struct usb_request *req;
394 struct uac_rtd_params *prm;
395 struct uac_params *params = &audio_dev->params;
398 ep = audio_dev->out_ep;
400 config_ep_by_speed(gadget, &audio_dev->func, ep);
401 req_len = prm->max_psize;
403 prm->ep_enabled = true;
406 for (i = 0; i < params->req_number; i++) {
407 if (!prm->ureq[i].req) {
408 req = usb_ep_alloc_request(ep, GFP_ATOMIC);
412 prm->ureq[i].req = req;
413 prm->ureq[i].pp = prm;
416 req->context = &prm->ureq[i];
417 req->length = req_len;
418 req->complete = u_audio_iso_complete;
419 req->buf = prm->rbuf + i * prm->max_psize;
422 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
423 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
428 EXPORT_SYMBOL_GPL(u_audio_start_capture);
430 void u_audio_stop_capture(struct g_audio *audio_dev)
432 struct snd_uac_chip *uac = audio_dev->uac;
434 free_ep(&uac->c_prm, audio_dev->out_ep);
436 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
438 int u_audio_start_playback(struct g_audio *audio_dev)
440 struct snd_uac_chip *uac = audio_dev->uac;
441 struct usb_gadget *gadget = audio_dev->gadget;
442 struct device *dev = &gadget->dev;
443 struct usb_request *req;
445 struct uac_rtd_params *prm;
446 struct uac_params *params = &audio_dev->params;
447 unsigned int factor, rate;
448 const struct usb_endpoint_descriptor *ep_desc;
451 ep = audio_dev->in_ep;
453 config_ep_by_speed(gadget, &audio_dev->func, ep);
457 /* pre-calculate the playback endpoint's interval */
458 if (gadget->speed == USB_SPEED_FULL)
463 /* pre-compute some values for iso_complete() */
464 uac->p_framesize = params->p_ssize *
465 num_channels(params->p_chmask);
466 rate = params->p_srate * uac->p_framesize;
467 uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
468 uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval,
471 if (uac->p_pktsize < prm->max_psize)
472 uac->p_pktsize_residue = rate % uac->p_interval;
474 uac->p_pktsize_residue = 0;
476 req_len = uac->p_pktsize;
479 prm->ep_enabled = true;
482 for (i = 0; i < params->req_number; i++) {
483 if (!prm->ureq[i].req) {
484 req = usb_ep_alloc_request(ep, GFP_ATOMIC);
488 prm->ureq[i].req = req;
489 prm->ureq[i].pp = prm;
492 req->context = &prm->ureq[i];
493 req->length = req_len;
494 req->complete = u_audio_iso_complete;
495 req->buf = prm->rbuf + i * prm->max_psize;
498 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
499 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
504 EXPORT_SYMBOL_GPL(u_audio_start_playback);
506 void u_audio_stop_playback(struct g_audio *audio_dev)
508 struct snd_uac_chip *uac = audio_dev->uac;
510 free_ep(&uac->p_prm, audio_dev->in_ep);
512 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
514 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
515 const char *card_name)
517 struct snd_uac_chip *uac;
518 struct snd_card *card;
520 struct uac_params *params;
521 int p_chmask, c_chmask;
527 uac = kzalloc(sizeof(*uac), GFP_KERNEL);
531 uac->audio_dev = g_audio;
533 params = &g_audio->params;
534 p_chmask = params->p_chmask;
535 c_chmask = params->c_chmask;
538 struct uac_rtd_params *prm = &uac->c_prm;
540 uac->c_prm.uac = uac;
541 prm->max_psize = g_audio->out_ep_maxpsize;
543 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
550 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
560 struct uac_rtd_params *prm = &uac->p_prm;
562 uac->p_prm.uac = uac;
563 prm->max_psize = g_audio->in_ep_maxpsize;
565 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
572 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
581 /* Choose any slot, with no id */
582 err = snd_card_new(&g_audio->gadget->dev,
583 -1, NULL, THIS_MODULE, 0, &card);
590 * Create first PCM device
591 * Create a substream only for non-zero channel streams
593 err = snd_pcm_new(uac->card, pcm_name, 0,
594 p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
598 strcpy(pcm->name, pcm_name);
599 pcm->private_data = uac;
602 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
603 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
605 strcpy(card->driver, card_name);
606 strcpy(card->shortname, card_name);
607 sprintf(card->longname, "%s %i", card_name, card->dev->id);
609 snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
610 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
612 err = snd_card_register(card);
620 kfree(uac->p_prm.ureq);
621 kfree(uac->c_prm.ureq);
622 kfree(uac->p_prm.rbuf);
623 kfree(uac->c_prm.rbuf);
628 EXPORT_SYMBOL_GPL(g_audio_setup);
630 void g_audio_cleanup(struct g_audio *g_audio)
632 struct snd_uac_chip *uac;
633 struct snd_card *card;
635 if (!g_audio || !g_audio->uac)
643 kfree(uac->p_prm.ureq);
644 kfree(uac->c_prm.ureq);
645 kfree(uac->p_prm.rbuf);
646 kfree(uac->c_prm.rbuf);
649 EXPORT_SYMBOL_GPL(g_audio_cleanup);
651 MODULE_LICENSE("GPL");
652 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
653 MODULE_AUTHOR("Ruslan Bilovol");