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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 *

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:

11 * Yadwinder Singh (yadi.brar01@gmail.com)

12 * Jaswinder Singh (jaswinder.singh@linaro.org)

13 */

15 #include <linux/module.h>

16 #include <sound/core.h>

17 #include <sound/pcm.h>

18 #include <sound/pcm_params.h>

20 #include "u_audio.h"

22 #define BUFF_SIZE_MAX (PAGE_SIZE * 16)

23 #define PRD_SIZE_MAX PAGE_SIZE

24 #define MIN_PERIODS 4

26 struct uac_req {

27 struct uac_rtd_params *pp; /* parent param */

28 struct usb_request *req;

29 };

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 */

36 size_t dma_bytes;

37 unsigned char *dma_area;

39 struct snd_pcm_substream *ss;

41 /* Ring buffer */

42 ssize_t hw_ptr;

44 void *rbuf;

46 size_t period_size;

48 unsigned max_psize; /* MaxPacketSize of endpoint */

49 struct uac_req *ureq;

51 spinlock_t lock;

52 };

54 struct snd_uac_chip {

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;

61 struct snd_pcm *pcm;

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;

71 };

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,

82 };

84 static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)

85 {

86 unsigned pending;

87 unsigned long flags;

88 unsigned int hw_ptr;

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)

98 return;

100 /*

101 * We can't really do much about bad xfers.

102 * Afterall, the ISOCH xfers could fail legitimately.

103 */

104 if (status)

105 pr_debug("%s: iso_complete status(%d) %d/%d\n",

106 __func__, status, req->actual, req->length);

107

108 substream = prm->ss;

109

110 /* Do nothing if ALSA isn't active */

111 if (!substream)

112 goto exit;

113

114 spin_lock_irqsave(&prm->lock, flags);

115

116 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

117 /*

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.

122 */

123 req->length = uac->p_pktsize;

124 uac->p_residue += uac->p_pktsize_residue;

125

126 /*

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.

130 */

131 if (uac->p_residue / uac->p_interval >= uac->p_framesize) {

132 req->length += uac->p_framesize;

133 uac->p_residue -= uac->p_framesize *

134 uac->p_interval;

135 }

136

137 req->actual = req->length;

138 }

139

140 pending = prm->hw_ptr % prm->period_size;

141 pending += req->actual;

142 if (pending >= prm->period_size)

143 update_alsa = true;

144

145 hw_ptr = prm->hw_ptr;

146 prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;

147

148 spin_unlock_irqrestore(&prm->lock, flags);

149

150 /* Pack USB load in ALSA ring buffer */

151 pending = prm->dma_bytes - hw_ptr;

152

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);

158 } else {

159 memcpy(req->buf, prm->dma_area + hw_ptr, req->actual);

160 }

161 } else {

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);

166 } else {

167 memcpy(prm->dma_area + hw_ptr, req->buf, req->actual);

168 }

169 }

170

171 exit:

172 if (usb_ep_queue(ep, req, GFP_ATOMIC))

173 dev_err(uac->card->dev, "%d Error!\n", __LINE__);

174

175 if (update_alsa)

176 snd_pcm_period_elapsed(substream);

177 }

178

179 static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd)

180 {

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;

185 unsigned long flags;

186 int err = 0;

187

188 audio_dev = uac->audio_dev;

189 params = &audio_dev->params;

190

191 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

192 prm = &uac->p_prm;

193 else

194 prm = &uac->c_prm;

195

196 spin_lock_irqsave(&prm->lock, flags);

197

198 /* Reset */

199 prm->hw_ptr = 0;

200

201 switch (cmd) {

202 case SNDRV_PCM_TRIGGER_START:

203 case SNDRV_PCM_TRIGGER_RESUME:

204 prm->ss = substream;

205 break;

206 case SNDRV_PCM_TRIGGER_STOP:

207 case SNDRV_PCM_TRIGGER_SUSPEND:

208 prm->ss = NULL;

209 break;

210 default:

211 err = -EINVAL;

212 }

213

214 spin_unlock_irqrestore(&prm->lock, flags);

215

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);

219

220 return err;

221 }

222

223 static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream)

224 {

225 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);

226 struct uac_rtd_params *prm;

227

228 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

229 prm = &uac->p_prm;

230 else

231 prm = &uac->c_prm;

232

233 return bytes_to_frames(substream->runtime, prm->hw_ptr);

234 }

235

236 static int uac_pcm_hw_params(struct snd_pcm_substream *substream,

237 struct snd_pcm_hw_params *hw_params)

238 {

239 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);

240 struct uac_rtd_params *prm;

241 int err;

242

243 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

244 prm = &uac->p_prm;

245 else

246 prm = &uac->c_prm;

247

248 err = snd_pcm_lib_malloc_pages(substream,

249 params_buffer_bytes(hw_params));

250 if (err >= 0) {

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);

254 }

255

256 return err;

257 }

258

259 static int uac_pcm_hw_free(struct snd_pcm_substream *substream)

260 {

261 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);

262 struct uac_rtd_params *prm;

263

264 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)

265 prm = &uac->p_prm;

266 else

267 prm = &uac->c_prm;

268

269 prm->dma_area = NULL;

270 prm->dma_bytes = 0;

271 prm->period_size = 0;

272

273 return snd_pcm_lib_free_pages(substream);

274 }

275

276 static int uac_pcm_open(struct snd_pcm_substream *substream)

277 {

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;

285

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;

294 uac->p_residue = 0;

295

296 runtime->hw = uac_pcm_hardware;

297

298 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

299 spin_lock_init(&uac->p_prm.lock);

300 runtime->hw.rate_min = p_srate;

301 switch (p_ssize) {

302 case 3:

303 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;

304 break;

305 case 4:

306 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;

307 break;

308 default:

309 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;

310 break;

311 }

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;

315 } else {

316 spin_lock_init(&uac->c_prm.lock);

317 runtime->hw.rate_min = c_srate;

318 switch (c_ssize) {

319 case 3:

320 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;

321 break;

322 case 4:

323 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;

324 break;

325 default:

326 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;

327 break;

328 }

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;

332 }

333

334 runtime->hw.rate_max = runtime->hw.rate_min;

335 runtime->hw.channels_max = runtime->hw.channels_min;

336

337 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);

338

339 return 0;

340 }

341

342 /* ALSA cries without these function pointers */

343 static int uac_pcm_null(struct snd_pcm_substream *substream)

344 {

345 return 0;

346 }

347

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,

357 };

358

359 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)

360 {

361 struct snd_uac_chip *uac = prm->uac;

362 struct g_audio *audio_dev;

363 struct uac_params *params;

364 int i;

365

366 if (!prm->ep_enabled)

367 return;

368

369 prm->ep_enabled = false;

370

371 audio_dev = uac->audio_dev;

372 params = &audio_dev->params;

373

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;

379 }

380 }

381

382 if (usb_ep_disable(ep))

383 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);

384 }

385

386

387 int u_audio_start_capture(struct g_audio *audio_dev)

388 {

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;

393 struct usb_ep *ep;

394 struct uac_rtd_params *prm;

395 struct uac_params *params = &audio_dev->params;

396 int req_len, i;

397

398 ep = audio_dev->out_ep;

399 prm = &uac->c_prm;

400 config_ep_by_speed(gadget, &audio_dev->func, ep);

401 req_len = prm->max_psize;

402

403 prm->ep_enabled = true;

404 usb_ep_enable(ep);

405

406 for (i = 0; i < params->req_number; i++) {

407 if (!prm->ureq[i].req) {

408 req = usb_ep_alloc_request(ep, GFP_ATOMIC);

409 if (req == NULL)

410 return -ENOMEM;

411

412 prm->ureq[i].req = req;

413 prm->ureq[i].pp = prm;

414

415 req->zero = 0;

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;

420 }

421

422 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))

423 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);

424 }

425

426 return 0;

427 }

428 EXPORT_SYMBOL_GPL(u_audio_start_capture);

429

430 void u_audio_stop_capture(struct g_audio *audio_dev)

431 {

432 struct snd_uac_chip *uac = audio_dev->uac;

433

434 free_ep(&uac->c_prm, audio_dev->out_ep);

435 }

436 EXPORT_SYMBOL_GPL(u_audio_stop_capture);

437

438 int u_audio_start_playback(struct g_audio *audio_dev)

439 {

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;

444 struct usb_ep *ep;

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;

449 int req_len, i;

450

451 ep = audio_dev->in_ep;

452 prm = &uac->p_prm;

453 config_ep_by_speed(gadget, &audio_dev->func, ep);

454

455 ep_desc = ep->desc;

456

457 /* pre-calculate the playback endpoint's interval */

458 if (gadget->speed == USB_SPEED_FULL)

459 factor = 1000;

460 else

461 factor = 8000;

462

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,

469 prm->max_psize);

470

471 if (uac->p_pktsize < prm->max_psize)

472 uac->p_pktsize_residue = rate % uac->p_interval;

473 else

474 uac->p_pktsize_residue = 0;

475

476 req_len = uac->p_pktsize;

477 uac->p_residue = 0;

478

479 prm->ep_enabled = true;

480 usb_ep_enable(ep);

481

482 for (i = 0; i < params->req_number; i++) {

483 if (!prm->ureq[i].req) {

484 req = usb_ep_alloc_request(ep, GFP_ATOMIC);

485 if (req == NULL)

486 return -ENOMEM;

487

488 prm->ureq[i].req = req;

489 prm->ureq[i].pp = prm;

490

491 req->zero = 0;

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;

496 }

497

498 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))

499 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);

500 }

501

502 return 0;

503 }

504 EXPORT_SYMBOL_GPL(u_audio_start_playback);

505

506 void u_audio_stop_playback(struct g_audio *audio_dev)

507 {

508 struct snd_uac_chip *uac = audio_dev->uac;

509

510 free_ep(&uac->p_prm, audio_dev->in_ep);

511 }

512 EXPORT_SYMBOL_GPL(u_audio_stop_playback);

513

514 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,

515 const char *card_name)

516 {

517 struct snd_uac_chip *uac;

518 struct snd_card *card;

519 struct snd_pcm *pcm;

520 struct uac_params *params;

521 int p_chmask, c_chmask;

522 int err;

523

524 if (!g_audio)

525 return -EINVAL;

526

527 uac = kzalloc(sizeof(*uac), GFP_KERNEL);

528 if (!uac)

529 return -ENOMEM;

530 g_audio->uac = uac;

531 uac->audio_dev = g_audio;

532

533 params = &g_audio->params;

534 p_chmask = params->p_chmask;

535 c_chmask = params->c_chmask;

536

537 if (c_chmask) {

538 struct uac_rtd_params *prm = &uac->c_prm;

539

540 uac->c_prm.uac = uac;

541 prm->max_psize = g_audio->out_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 if (p_chmask) {

560 struct uac_rtd_params *prm = &uac->p_prm;

561

562 uac->p_prm.uac = uac;

563 prm->max_psize = g_audio->in_ep_maxpsize;

564

565 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),

566 GFP_KERNEL);

567 if (!prm->ureq) {

568 err = -ENOMEM;

569 goto fail;

570 }

571

572 prm->rbuf = kcalloc(params->req_number, prm->max_psize,

573 GFP_KERNEL);

574 if (!prm->rbuf) {

575 prm->max_psize = 0;

576 err = -ENOMEM;

577 goto fail;

578 }

579 }

580

581 /* Choose any slot, with no id */

582 err = snd_card_new(&g_audio->gadget->dev,

583 -1, NULL, THIS_MODULE, 0, &card);

584 if (err < 0)

585 goto fail;

586

587 uac->card = card;

588

589 /*

590 * Create first PCM device

591 * Create a substream only for non-zero channel streams

592 */

593 err = snd_pcm_new(uac->card, pcm_name, 0,

594 p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);

595 if (err < 0)

596 goto snd_fail;

597

598 strcpy(pcm->name, pcm_name);

599 pcm->private_data = uac;

600 uac->pcm = pcm;

601

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);

604

605 strcpy(card->driver, card_name);

606 strcpy(card->shortname, card_name);

607 sprintf(card->longname, "%s %i", card_name, card->dev->id);

608

609 snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,

610 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);

611

612 err = snd_card_register(card);

613

614 if (!err)

615 return 0;

616

617 snd_fail:

618 snd_card_free(card);

619 fail:

620 kfree(uac->p_prm.ureq);

621 kfree(uac->c_prm.ureq);

622 kfree(uac->p_prm.rbuf);

623 kfree(uac->c_prm.rbuf);

624 kfree(uac);

625

626 return err;

627 }

628 EXPORT_SYMBOL_GPL(g_audio_setup);

629

630 void g_audio_cleanup(struct g_audio *g_audio)

631 {

632 struct snd_uac_chip *uac;

633 struct snd_card *card;

634

635 if (!g_audio || !g_audio->uac)

636 return;

637

638 uac = g_audio->uac;

639 card = uac->card;

640 if (card)

641 snd_card_free(card);

642

643 kfree(uac->p_prm.ureq);

644 kfree(uac->c_prm.ureq);

645 kfree(uac->p_prm.rbuf);

646 kfree(uac->c_prm.rbuf);

647 kfree(uac);

648 }

649 EXPORT_SYMBOL_GPL(g_audio_cleanup);

650

651 MODULE_LICENSE("GPL");

652 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");

653 MODULE_AUTHOR("Ruslan Bilovol");