xref: /linux/sound/usb/format.c (revision 987b741c52c7c6c68d46fbaeb95b8d1087f10b7f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/init.h>
6 #include <linux/slab.h>
7 #include <linux/usb.h>
8 #include <linux/usb/audio.h>
9 #include <linux/usb/audio-v2.h>
10 #include <linux/usb/audio-v3.h>
11 
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 
15 #include "usbaudio.h"
16 #include "card.h"
17 #include "quirks.h"
18 #include "helper.h"
19 #include "clock.h"
20 #include "format.h"
21 
22 /*
23  * parse the audio format type I descriptor
24  * and returns the corresponding pcm format
25  *
26  * @dev: usb device
27  * @fp: audioformat record
28  * @format: the format tag (wFormatTag)
29  * @fmt: the format type descriptor (v1/v2) or AudioStreaming descriptor (v3)
30  */
31 static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
32 				     struct audioformat *fp,
33 				     u64 format, void *_fmt)
34 {
35 	int sample_width, sample_bytes;
36 	u64 pcm_formats = 0;
37 
38 	switch (fp->protocol) {
39 	case UAC_VERSION_1:
40 	default: {
41 		struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
42 		if (format >= 64)
43 			return 0; /* invalid format */
44 		sample_width = fmt->bBitResolution;
45 		sample_bytes = fmt->bSubframeSize;
46 		format = 1ULL << format;
47 		break;
48 	}
49 
50 	case UAC_VERSION_2: {
51 		struct uac_format_type_i_ext_descriptor *fmt = _fmt;
52 		sample_width = fmt->bBitResolution;
53 		sample_bytes = fmt->bSubslotSize;
54 
55 		if (format & UAC2_FORMAT_TYPE_I_RAW_DATA) {
56 			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
57 			/* flag potentially raw DSD capable altsettings */
58 			fp->dsd_raw = true;
59 		}
60 
61 		format <<= 1;
62 		break;
63 	}
64 	case UAC_VERSION_3: {
65 		struct uac3_as_header_descriptor *as = _fmt;
66 
67 		sample_width = as->bBitResolution;
68 		sample_bytes = as->bSubslotSize;
69 
70 		if (format & UAC3_FORMAT_TYPE_I_RAW_DATA)
71 			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
72 
73 		format <<= 1;
74 		break;
75 	}
76 	}
77 
78 	fp->fmt_bits = sample_width;
79 
80 	if ((pcm_formats == 0) &&
81 	    (format == 0 || format == (1 << UAC_FORMAT_TYPE_I_UNDEFINED))) {
82 		/* some devices don't define this correctly... */
83 		usb_audio_info(chip, "%u:%d : format type 0 is detected, processed as PCM\n",
84 			fp->iface, fp->altsetting);
85 		format = 1 << UAC_FORMAT_TYPE_I_PCM;
86 	}
87 	if (format & (1 << UAC_FORMAT_TYPE_I_PCM)) {
88 		if (((chip->usb_id == USB_ID(0x0582, 0x0016)) ||
89 		     /* Edirol SD-90 */
90 		     (chip->usb_id == USB_ID(0x0582, 0x000c))) &&
91 		     /* Roland SC-D70 */
92 		    sample_width == 24 && sample_bytes == 2)
93 			sample_bytes = 3;
94 		else if (sample_width > sample_bytes * 8) {
95 			usb_audio_info(chip, "%u:%d : sample bitwidth %d in over sample bytes %d\n",
96 				 fp->iface, fp->altsetting,
97 				 sample_width, sample_bytes);
98 		}
99 		/* check the format byte size */
100 		switch (sample_bytes) {
101 		case 1:
102 			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
103 			break;
104 		case 2:
105 			if (snd_usb_is_big_endian_format(chip, fp))
106 				pcm_formats |= SNDRV_PCM_FMTBIT_S16_BE; /* grrr, big endian!! */
107 			else
108 				pcm_formats |= SNDRV_PCM_FMTBIT_S16_LE;
109 			break;
110 		case 3:
111 			if (snd_usb_is_big_endian_format(chip, fp))
112 				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3BE; /* grrr, big endian!! */
113 			else
114 				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3LE;
115 			break;
116 		case 4:
117 			pcm_formats |= SNDRV_PCM_FMTBIT_S32_LE;
118 			break;
119 		default:
120 			usb_audio_info(chip,
121 				 "%u:%d : unsupported sample bitwidth %d in %d bytes\n",
122 				 fp->iface, fp->altsetting,
123 				 sample_width, sample_bytes);
124 			break;
125 		}
126 	}
127 	if (format & (1 << UAC_FORMAT_TYPE_I_PCM8)) {
128 		/* Dallas DS4201 workaround: it advertises U8 format, but really
129 		   supports S8. */
130 		if (chip->usb_id == USB_ID(0x04fa, 0x4201))
131 			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
132 		else
133 			pcm_formats |= SNDRV_PCM_FMTBIT_U8;
134 	}
135 	if (format & (1 << UAC_FORMAT_TYPE_I_IEEE_FLOAT)) {
136 		pcm_formats |= SNDRV_PCM_FMTBIT_FLOAT_LE;
137 	}
138 	if (format & (1 << UAC_FORMAT_TYPE_I_ALAW)) {
139 		pcm_formats |= SNDRV_PCM_FMTBIT_A_LAW;
140 	}
141 	if (format & (1 << UAC_FORMAT_TYPE_I_MULAW)) {
142 		pcm_formats |= SNDRV_PCM_FMTBIT_MU_LAW;
143 	}
144 	if (format & ~0x3f) {
145 		usb_audio_info(chip,
146 			 "%u:%d : unsupported format bits %#llx\n",
147 			 fp->iface, fp->altsetting, format);
148 	}
149 
150 	pcm_formats |= snd_usb_interface_dsd_format_quirks(chip, fp, sample_bytes);
151 
152 	return pcm_formats;
153 }
154 
155 static int set_fixed_rate(struct audioformat *fp, int rate, int rate_bits)
156 {
157 	kfree(fp->rate_table);
158 	fp->rate_table = kmalloc(sizeof(int), GFP_KERNEL);
159 	if (!fp->rate_table)
160 		return -ENOMEM;
161 	fp->nr_rates = 1;
162 	fp->rate_min = rate;
163 	fp->rate_max = rate;
164 	fp->rates = rate_bits;
165 	fp->rate_table[0] = rate;
166 	return 0;
167 }
168 
169 /* set up rate_min, rate_max and rates from the rate table */
170 static void set_rate_table_min_max(struct audioformat *fp)
171 {
172 	unsigned int rate;
173 	int i;
174 
175 	fp->rate_min = INT_MAX;
176 	fp->rate_max = 0;
177 	fp->rates = 0;
178 	for (i = 0; i < fp->nr_rates; i++) {
179 		rate = fp->rate_table[i];
180 		fp->rate_min = min(fp->rate_min, rate);
181 		fp->rate_max = max(fp->rate_max, rate);
182 		fp->rates |= snd_pcm_rate_to_rate_bit(rate);
183 	}
184 }
185 
186 /*
187  * parse the format descriptor and stores the possible sample rates
188  * on the audioformat table (audio class v1).
189  *
190  * @dev: usb device
191  * @fp: audioformat record
192  * @fmt: the format descriptor
193  * @offset: the start offset of descriptor pointing the rate type
194  *          (7 for type I and II, 8 for type II)
195  */
196 static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audioformat *fp,
197 				       unsigned char *fmt, int offset)
198 {
199 	int nr_rates = fmt[offset];
200 
201 	if (fmt[0] < offset + 1 + 3 * (nr_rates ? nr_rates : 2)) {
202 		usb_audio_err(chip,
203 			"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
204 			fp->iface, fp->altsetting);
205 		return -EINVAL;
206 	}
207 
208 	if (nr_rates) {
209 		/*
210 		 * build the rate table and bitmap flags
211 		 */
212 		int r, idx;
213 
214 		fp->rate_table = kmalloc_array(nr_rates, sizeof(int),
215 					       GFP_KERNEL);
216 		if (fp->rate_table == NULL)
217 			return -ENOMEM;
218 
219 		fp->nr_rates = 0;
220 		for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) {
221 			unsigned int rate = combine_triple(&fmt[idx]);
222 			if (!rate)
223 				continue;
224 			/* C-Media CM6501 mislabels its 96 kHz altsetting */
225 			/* Terratec Aureon 7.1 USB C-Media 6206, too */
226 			if (rate == 48000 && nr_rates == 1 &&
227 			    (chip->usb_id == USB_ID(0x0d8c, 0x0201) ||
228 			     chip->usb_id == USB_ID(0x0d8c, 0x0102) ||
229 			     chip->usb_id == USB_ID(0x0ccd, 0x00b1)) &&
230 			    fp->altsetting == 5 && fp->maxpacksize == 392)
231 				rate = 96000;
232 			/* Creative VF0420/VF0470 Live Cams report 16 kHz instead of 8kHz */
233 			if (rate == 16000 &&
234 			    (chip->usb_id == USB_ID(0x041e, 0x4064) ||
235 			     chip->usb_id == USB_ID(0x041e, 0x4068)))
236 				rate = 8000;
237 
238 			fp->rate_table[fp->nr_rates++] = rate;
239 		}
240 		if (!fp->nr_rates) {
241 			usb_audio_info(chip,
242 				       "%u:%d: All rates were zero\n",
243 				       fp->iface, fp->altsetting);
244 			return -EINVAL;
245 		}
246 		set_rate_table_min_max(fp);
247 	} else {
248 		/* continuous rates */
249 		fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
250 		fp->rate_min = combine_triple(&fmt[offset + 1]);
251 		fp->rate_max = combine_triple(&fmt[offset + 4]);
252 	}
253 
254 	/* Jabra Evolve 65 headset */
255 	if (chip->usb_id == USB_ID(0x0b0e, 0x030b)) {
256 		/* only 48kHz for playback while keeping 16kHz for capture */
257 		if (fp->nr_rates != 1)
258 			return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
259 	}
260 
261 	return 0;
262 }
263 
264 
265 /*
266  * Presonus Studio 1810c supports a limited set of sampling
267  * rates per altsetting but reports the full set each time.
268  * If we don't filter out the unsupported rates and attempt
269  * to configure the card, it will hang refusing to do any
270  * further audio I/O until a hard reset is performed.
271  *
272  * The list of supported rates per altsetting (set of available
273  * I/O channels) is described in the owner's manual, section 2.2.
274  */
275 static bool s1810c_valid_sample_rate(struct audioformat *fp,
276 				     unsigned int rate)
277 {
278 	switch (fp->altsetting) {
279 	case 1:
280 		/* All ADAT ports available */
281 		return rate <= 48000;
282 	case 2:
283 		/* Half of ADAT ports available */
284 		return (rate == 88200 || rate == 96000);
285 	case 3:
286 		/* Analog I/O only (no S/PDIF nor ADAT) */
287 		return rate >= 176400;
288 	default:
289 		return false;
290 	}
291 	return false;
292 }
293 
294 /*
295  * Many Focusrite devices supports a limited set of sampling rates per
296  * altsetting. Maximum rate is exposed in the last 4 bytes of Format Type
297  * descriptor which has a non-standard bLength = 10.
298  */
299 static bool focusrite_valid_sample_rate(struct snd_usb_audio *chip,
300 					struct audioformat *fp,
301 					unsigned int rate)
302 {
303 	struct usb_interface *iface;
304 	struct usb_host_interface *alts;
305 	unsigned char *fmt;
306 	unsigned int max_rate;
307 
308 	iface = usb_ifnum_to_if(chip->dev, fp->iface);
309 	if (!iface)
310 		return true;
311 
312 	alts = &iface->altsetting[fp->altset_idx];
313 	fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,
314 				      NULL, UAC_FORMAT_TYPE);
315 	if (!fmt)
316 		return true;
317 
318 	if (fmt[0] == 10) { /* bLength */
319 		max_rate = combine_quad(&fmt[6]);
320 
321 		/* Validate max rate */
322 		if (max_rate != 48000 &&
323 		    max_rate != 96000 &&
324 		    max_rate != 192000 &&
325 		    max_rate != 384000) {
326 
327 			usb_audio_info(chip,
328 				"%u:%d : unexpected max rate: %u\n",
329 				fp->iface, fp->altsetting, max_rate);
330 
331 			return true;
332 		}
333 
334 		return rate <= max_rate;
335 	}
336 
337 	return true;
338 }
339 
340 /*
341  * Helper function to walk the array of sample rate triplets reported by
342  * the device. The problem is that we need to parse whole array first to
343  * get to know how many sample rates we have to expect.
344  * Then fp->rate_table can be allocated and filled.
345  */
346 static int parse_uac2_sample_rate_range(struct snd_usb_audio *chip,
347 					struct audioformat *fp, int nr_triplets,
348 					const unsigned char *data)
349 {
350 	int i, nr_rates = 0;
351 
352 	for (i = 0; i < nr_triplets; i++) {
353 		int min = combine_quad(&data[2 + 12 * i]);
354 		int max = combine_quad(&data[6 + 12 * i]);
355 		int res = combine_quad(&data[10 + 12 * i]);
356 		unsigned int rate;
357 
358 		if ((max < 0) || (min < 0) || (res < 0) || (max < min))
359 			continue;
360 
361 		/*
362 		 * for ranges with res == 1, we announce a continuous sample
363 		 * rate range, and this function should return 0 for no further
364 		 * parsing.
365 		 */
366 		if (res == 1) {
367 			fp->rate_min = min;
368 			fp->rate_max = max;
369 			fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
370 			return 0;
371 		}
372 
373 		for (rate = min; rate <= max; rate += res) {
374 
375 			/* Filter out invalid rates on Presonus Studio 1810c */
376 			if (chip->usb_id == USB_ID(0x0194f, 0x010c) &&
377 			    !s1810c_valid_sample_rate(fp, rate))
378 				goto skip_rate;
379 
380 			/* Filter out invalid rates on Focusrite devices */
381 			if (USB_ID_VENDOR(chip->usb_id) == 0x1235 &&
382 			    !focusrite_valid_sample_rate(chip, fp, rate))
383 				goto skip_rate;
384 
385 			if (fp->rate_table)
386 				fp->rate_table[nr_rates] = rate;
387 			nr_rates++;
388 			if (nr_rates >= MAX_NR_RATES) {
389 				usb_audio_err(chip, "invalid uac2 rates\n");
390 				break;
391 			}
392 
393 skip_rate:
394 			/* avoid endless loop */
395 			if (res == 0)
396 				break;
397 		}
398 	}
399 
400 	return nr_rates;
401 }
402 
403 /* Line6 Helix series and the Rode Rodecaster Pro don't support the
404  * UAC2_CS_RANGE usb function call. Return a static table of known
405  * clock rates.
406  */
407 static int line6_parse_audio_format_rates_quirk(struct snd_usb_audio *chip,
408 						struct audioformat *fp)
409 {
410 	switch (chip->usb_id) {
411 	case USB_ID(0x0e41, 0x4241): /* Line6 Helix */
412 	case USB_ID(0x0e41, 0x4242): /* Line6 Helix Rack */
413 	case USB_ID(0x0e41, 0x4244): /* Line6 Helix LT */
414 	case USB_ID(0x0e41, 0x4246): /* Line6 HX-Stomp */
415 	case USB_ID(0x0e41, 0x4247): /* Line6 Pod Go */
416 	case USB_ID(0x0e41, 0x4248): /* Line6 Helix >= fw 2.82 */
417 	case USB_ID(0x0e41, 0x4249): /* Line6 Helix Rack >= fw 2.82 */
418 	case USB_ID(0x0e41, 0x424a): /* Line6 Helix LT >= fw 2.82 */
419 	case USB_ID(0x19f7, 0x0011): /* Rode Rodecaster Pro */
420 		return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
421 	}
422 
423 	return -ENODEV;
424 }
425 
426 /* check whether the given altsetting is supported for the already set rate */
427 static bool check_valid_altsetting_v2v3(struct snd_usb_audio *chip, int iface,
428 					int altsetting)
429 {
430 	struct usb_device *dev = chip->dev;
431 	__le64 raw_data = 0;
432 	u64 data;
433 	int err;
434 
435 	/* we assume 64bit is enough for any altsettings */
436 	if (snd_BUG_ON(altsetting >= 64 - 8))
437 		return false;
438 
439 	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
440 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
441 			      UAC2_AS_VAL_ALT_SETTINGS << 8,
442 			      iface, &raw_data, sizeof(raw_data));
443 	if (err < 0)
444 		return false;
445 
446 	data = le64_to_cpu(raw_data);
447 	/* first byte contains the bitmap size */
448 	if ((data & 0xff) * 8 < altsetting)
449 		return false;
450 	if (data & (1ULL << (altsetting + 8)))
451 		return true;
452 
453 	return false;
454 }
455 
456 /*
457  * Validate each sample rate with the altsetting
458  * Rebuild the rate table if only partial values are valid
459  */
460 static int validate_sample_rate_table_v2v3(struct snd_usb_audio *chip,
461 					   struct audioformat *fp,
462 					   int clock)
463 {
464 	struct usb_device *dev = chip->dev;
465 	unsigned int *table;
466 	unsigned int nr_rates;
467 	int i, err;
468 
469 	/* performing the rate verification may lead to unexpected USB bus
470 	 * behavior afterwards by some unknown reason.  Do this only for the
471 	 * known devices.
472 	 */
473 	switch (USB_ID_VENDOR(chip->usb_id)) {
474 	case 0x07fd: /* MOTU */
475 		break;
476 	default:
477 		return 0; /* don't perform the validation as default */
478 	}
479 
480 	table = kcalloc(fp->nr_rates, sizeof(*table), GFP_KERNEL);
481 	if (!table)
482 		return -ENOMEM;
483 
484 	/* clear the interface altsetting at first */
485 	usb_set_interface(dev, fp->iface, 0);
486 
487 	nr_rates = 0;
488 	for (i = 0; i < fp->nr_rates; i++) {
489 		err = snd_usb_set_sample_rate_v2v3(chip, fp, clock,
490 						   fp->rate_table[i]);
491 		if (err < 0)
492 			continue;
493 
494 		if (check_valid_altsetting_v2v3(chip, fp->iface, fp->altsetting))
495 			table[nr_rates++] = fp->rate_table[i];
496 	}
497 
498 	if (!nr_rates) {
499 		usb_audio_dbg(chip,
500 			      "No valid sample rate available for %d:%d, assuming a firmware bug\n",
501 			      fp->iface, fp->altsetting);
502 		nr_rates = fp->nr_rates; /* continue as is */
503 	}
504 
505 	if (fp->nr_rates == nr_rates) {
506 		kfree(table);
507 		return 0;
508 	}
509 
510 	kfree(fp->rate_table);
511 	fp->rate_table = table;
512 	fp->nr_rates = nr_rates;
513 	return 0;
514 }
515 
516 /*
517  * parse the format descriptor and stores the possible sample rates
518  * on the audioformat table (audio class v2 and v3).
519  */
520 static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
521 				       struct audioformat *fp)
522 {
523 	struct usb_device *dev = chip->dev;
524 	unsigned char tmp[2], *data;
525 	int nr_triplets, data_size, ret = 0, ret_l6;
526 	int clock = snd_usb_clock_find_source(chip, fp, false);
527 
528 	if (clock < 0) {
529 		dev_err(&dev->dev,
530 			"%s(): unable to find clock source (clock %d)\n",
531 				__func__, clock);
532 		goto err;
533 	}
534 
535 	/* get the number of sample rates first by only fetching 2 bytes */
536 	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
537 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
538 			      UAC2_CS_CONTROL_SAM_FREQ << 8,
539 			      snd_usb_ctrl_intf(chip) | (clock << 8),
540 			      tmp, sizeof(tmp));
541 
542 	if (ret < 0) {
543 		/* line6 helix devices don't support UAC2_CS_CONTROL_SAM_FREQ call */
544 		ret_l6 = line6_parse_audio_format_rates_quirk(chip, fp);
545 		if (ret_l6 == -ENODEV) {
546 			/* no line6 device found continue showing the error */
547 			dev_err(&dev->dev,
548 				"%s(): unable to retrieve number of sample rates (clock %d)\n",
549 				__func__, clock);
550 			goto err;
551 		}
552 		if (ret_l6 == 0) {
553 			dev_info(&dev->dev,
554 				"%s(): unable to retrieve number of sample rates: set it to a predefined value (clock %d).\n",
555 				__func__, clock);
556 			return 0;
557 		}
558 		ret = ret_l6;
559 		goto err;
560 	}
561 
562 	nr_triplets = (tmp[1] << 8) | tmp[0];
563 	data_size = 2 + 12 * nr_triplets;
564 	data = kzalloc(data_size, GFP_KERNEL);
565 	if (!data) {
566 		ret = -ENOMEM;
567 		goto err;
568 	}
569 
570 	/* now get the full information */
571 	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
572 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
573 			      UAC2_CS_CONTROL_SAM_FREQ << 8,
574 			      snd_usb_ctrl_intf(chip) | (clock << 8),
575 			      data, data_size);
576 
577 	if (ret < 0) {
578 		dev_err(&dev->dev,
579 			"%s(): unable to retrieve sample rate range (clock %d)\n",
580 				__func__, clock);
581 		ret = -EINVAL;
582 		goto err_free;
583 	}
584 
585 	/* Call the triplet parser, and make sure fp->rate_table is NULL.
586 	 * We just use the return value to know how many sample rates we
587 	 * will have to deal with. */
588 	kfree(fp->rate_table);
589 	fp->rate_table = NULL;
590 	fp->nr_rates = parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
591 
592 	if (fp->nr_rates == 0) {
593 		/* SNDRV_PCM_RATE_CONTINUOUS */
594 		ret = 0;
595 		goto err_free;
596 	}
597 
598 	fp->rate_table = kmalloc_array(fp->nr_rates, sizeof(int), GFP_KERNEL);
599 	if (!fp->rate_table) {
600 		ret = -ENOMEM;
601 		goto err_free;
602 	}
603 
604 	/* Call the triplet parser again, but this time, fp->rate_table is
605 	 * allocated, so the rates will be stored */
606 	parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
607 
608 	ret = validate_sample_rate_table_v2v3(chip, fp, clock);
609 	if (ret < 0)
610 		goto err_free;
611 
612 	set_rate_table_min_max(fp);
613 
614 err_free:
615 	kfree(data);
616 err:
617 	return ret;
618 }
619 
620 /*
621  * parse the format type I and III descriptors
622  */
623 static int parse_audio_format_i(struct snd_usb_audio *chip,
624 				struct audioformat *fp, u64 format,
625 				void *_fmt)
626 {
627 	snd_pcm_format_t pcm_format;
628 	unsigned int fmt_type;
629 	int ret;
630 
631 	switch (fp->protocol) {
632 	default:
633 	case UAC_VERSION_1:
634 	case UAC_VERSION_2: {
635 		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
636 
637 		fmt_type = fmt->bFormatType;
638 		break;
639 	}
640 	case UAC_VERSION_3: {
641 		/* fp->fmt_type is already set in this case */
642 		fmt_type = fp->fmt_type;
643 		break;
644 	}
645 	}
646 
647 	if (fmt_type == UAC_FORMAT_TYPE_III) {
648 		/* FIXME: the format type is really IECxxx
649 		 *        but we give normal PCM format to get the existing
650 		 *        apps working...
651 		 */
652 		switch (chip->usb_id) {
653 
654 		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
655 			if (chip->setup == 0x00 &&
656 			    fp->altsetting == 6)
657 				pcm_format = SNDRV_PCM_FORMAT_S16_BE;
658 			else
659 				pcm_format = SNDRV_PCM_FORMAT_S16_LE;
660 			break;
661 		default:
662 			pcm_format = SNDRV_PCM_FORMAT_S16_LE;
663 		}
664 		fp->formats = pcm_format_to_bits(pcm_format);
665 	} else {
666 		fp->formats = parse_audio_format_i_type(chip, fp, format, _fmt);
667 		if (!fp->formats)
668 			return -EINVAL;
669 	}
670 
671 	/* gather possible sample rates */
672 	/* audio class v1 reports possible sample rates as part of the
673 	 * proprietary class specific descriptor.
674 	 * audio class v2 uses class specific EP0 range requests for that.
675 	 */
676 	switch (fp->protocol) {
677 	default:
678 	case UAC_VERSION_1: {
679 		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
680 
681 		fp->channels = fmt->bNrChannels;
682 		ret = parse_audio_format_rates_v1(chip, fp, (unsigned char *) fmt, 7);
683 		break;
684 	}
685 	case UAC_VERSION_2:
686 	case UAC_VERSION_3: {
687 		/* fp->channels is already set in this case */
688 		ret = parse_audio_format_rates_v2v3(chip, fp);
689 		break;
690 	}
691 	}
692 
693 	if (fp->channels < 1) {
694 		usb_audio_err(chip,
695 			"%u:%d : invalid channels %d\n",
696 			fp->iface, fp->altsetting, fp->channels);
697 		return -EINVAL;
698 	}
699 
700 	return ret;
701 }
702 
703 /*
704  * parse the format type II descriptor
705  */
706 static int parse_audio_format_ii(struct snd_usb_audio *chip,
707 				 struct audioformat *fp,
708 				 u64 format, void *_fmt)
709 {
710 	int brate, framesize, ret;
711 
712 	switch (format) {
713 	case UAC_FORMAT_TYPE_II_AC3:
714 		/* FIXME: there is no AC3 format defined yet */
715 		// fp->formats = SNDRV_PCM_FMTBIT_AC3;
716 		fp->formats = SNDRV_PCM_FMTBIT_U8; /* temporary hack to receive byte streams */
717 		break;
718 	case UAC_FORMAT_TYPE_II_MPEG:
719 		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
720 		break;
721 	default:
722 		usb_audio_info(chip,
723 			 "%u:%d : unknown format tag %#llx is detected.  processed as MPEG.\n",
724 			 fp->iface, fp->altsetting, format);
725 		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
726 		break;
727 	}
728 
729 	fp->channels = 1;
730 
731 	switch (fp->protocol) {
732 	default:
733 	case UAC_VERSION_1: {
734 		struct uac_format_type_ii_discrete_descriptor *fmt = _fmt;
735 		brate = le16_to_cpu(fmt->wMaxBitRate);
736 		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
737 		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
738 		fp->frame_size = framesize;
739 		ret = parse_audio_format_rates_v1(chip, fp, _fmt, 8); /* fmt[8..] sample rates */
740 		break;
741 	}
742 	case UAC_VERSION_2: {
743 		struct uac_format_type_ii_ext_descriptor *fmt = _fmt;
744 		brate = le16_to_cpu(fmt->wMaxBitRate);
745 		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
746 		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
747 		fp->frame_size = framesize;
748 		ret = parse_audio_format_rates_v2v3(chip, fp);
749 		break;
750 	}
751 	}
752 
753 	return ret;
754 }
755 
756 int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
757 			       struct audioformat *fp, u64 format,
758 			       struct uac_format_type_i_continuous_descriptor *fmt,
759 			       int stream)
760 {
761 	int err;
762 
763 	switch (fmt->bFormatType) {
764 	case UAC_FORMAT_TYPE_I:
765 	case UAC_FORMAT_TYPE_III:
766 		err = parse_audio_format_i(chip, fp, format, fmt);
767 		break;
768 	case UAC_FORMAT_TYPE_II:
769 		err = parse_audio_format_ii(chip, fp, format, fmt);
770 		break;
771 	default:
772 		usb_audio_info(chip,
773 			 "%u:%d : format type %d is not supported yet\n",
774 			 fp->iface, fp->altsetting,
775 			 fmt->bFormatType);
776 		return -ENOTSUPP;
777 	}
778 	fp->fmt_type = fmt->bFormatType;
779 	if (err < 0)
780 		return err;
781 #if 1
782 	/* FIXME: temporary hack for extigy/audigy 2 nx/zs */
783 	/* extigy apparently supports sample rates other than 48k
784 	 * but not in ordinary way.  so we enable only 48k atm.
785 	 */
786 	if (chip->usb_id == USB_ID(0x041e, 0x3000) ||
787 	    chip->usb_id == USB_ID(0x041e, 0x3020) ||
788 	    chip->usb_id == USB_ID(0x041e, 0x3061)) {
789 		if (fmt->bFormatType == UAC_FORMAT_TYPE_I &&
790 		    fp->rates != SNDRV_PCM_RATE_48000 &&
791 		    fp->rates != SNDRV_PCM_RATE_96000)
792 			return -ENOTSUPP;
793 	}
794 #endif
795 	return 0;
796 }
797 
798 int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
799 			       struct audioformat *fp,
800 			       struct uac3_as_header_descriptor *as,
801 			       int stream)
802 {
803 	u64 format = le64_to_cpu(as->bmFormats);
804 	int err;
805 
806 	/*
807 	 * Type I format bits are D0..D6
808 	 * This test works because type IV is not supported
809 	 */
810 	if (format & 0x7f)
811 		fp->fmt_type = UAC_FORMAT_TYPE_I;
812 	else
813 		fp->fmt_type = UAC_FORMAT_TYPE_III;
814 
815 	err = parse_audio_format_i(chip, fp, format, as);
816 	if (err < 0)
817 		return err;
818 
819 	return 0;
820 }
821