xref: /openbmc/linux/sound/usb/format.c (revision 93db51d06b32227319dae2ac289029ccf1b33181)
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 "debug.h"
20 #include "clock.h"
21 #include "format.h"
22 
23 /*
24  * parse the audio format type I descriptor
25  * and returns the corresponding pcm format
26  *
27  * @dev: usb device
28  * @fp: audioformat record
29  * @format: the format tag (wFormatTag)
30  * @fmt: the format type descriptor (v1/v2) or AudioStreaming descriptor (v3)
31  */
32 static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
33 				     struct audioformat *fp,
34 				     u64 format, void *_fmt)
35 {
36 	int sample_width, sample_bytes;
37 	u64 pcm_formats = 0;
38 
39 	switch (fp->protocol) {
40 	case UAC_VERSION_1:
41 	default: {
42 		struct uac_format_type_i_discrete_descriptor *fmt = _fmt;
43 		sample_width = fmt->bBitResolution;
44 		sample_bytes = fmt->bSubframeSize;
45 		format = 1ULL << format;
46 		break;
47 	}
48 
49 	case UAC_VERSION_2: {
50 		struct uac_format_type_i_ext_descriptor *fmt = _fmt;
51 		sample_width = fmt->bBitResolution;
52 		sample_bytes = fmt->bSubslotSize;
53 
54 		if (format & UAC2_FORMAT_TYPE_I_RAW_DATA) {
55 			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
56 			/* flag potentially raw DSD capable altsettings */
57 			fp->dsd_raw = true;
58 		}
59 
60 		format <<= 1;
61 		break;
62 	}
63 	case UAC_VERSION_3: {
64 		struct uac3_as_header_descriptor *as = _fmt;
65 
66 		sample_width = as->bBitResolution;
67 		sample_bytes = as->bSubslotSize;
68 
69 		if (format & UAC3_FORMAT_TYPE_I_RAW_DATA)
70 			pcm_formats |= SNDRV_PCM_FMTBIT_SPECIAL;
71 
72 		format <<= 1;
73 		break;
74 	}
75 	}
76 
77 	fp->fmt_bits = sample_width;
78 
79 	if ((pcm_formats == 0) &&
80 	    (format == 0 || format == (1 << UAC_FORMAT_TYPE_I_UNDEFINED))) {
81 		/* some devices don't define this correctly... */
82 		usb_audio_info(chip, "%u:%d : format type 0 is detected, processed as PCM\n",
83 			fp->iface, fp->altsetting);
84 		format = 1 << UAC_FORMAT_TYPE_I_PCM;
85 	}
86 	if (format & (1 << UAC_FORMAT_TYPE_I_PCM)) {
87 		if (((chip->usb_id == USB_ID(0x0582, 0x0016)) ||
88 		     /* Edirol SD-90 */
89 		     (chip->usb_id == USB_ID(0x0582, 0x000c))) &&
90 		     /* Roland SC-D70 */
91 		    sample_width == 24 && sample_bytes == 2)
92 			sample_bytes = 3;
93 		else if (sample_width > sample_bytes * 8) {
94 			usb_audio_info(chip, "%u:%d : sample bitwidth %d in over sample bytes %d\n",
95 				 fp->iface, fp->altsetting,
96 				 sample_width, sample_bytes);
97 		}
98 		/* check the format byte size */
99 		switch (sample_bytes) {
100 		case 1:
101 			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
102 			break;
103 		case 2:
104 			if (snd_usb_is_big_endian_format(chip, fp))
105 				pcm_formats |= SNDRV_PCM_FMTBIT_S16_BE; /* grrr, big endian!! */
106 			else
107 				pcm_formats |= SNDRV_PCM_FMTBIT_S16_LE;
108 			break;
109 		case 3:
110 			if (snd_usb_is_big_endian_format(chip, fp))
111 				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3BE; /* grrr, big endian!! */
112 			else
113 				pcm_formats |= SNDRV_PCM_FMTBIT_S24_3LE;
114 			break;
115 		case 4:
116 			pcm_formats |= SNDRV_PCM_FMTBIT_S32_LE;
117 			break;
118 		default:
119 			usb_audio_info(chip,
120 				 "%u:%d : unsupported sample bitwidth %d in %d bytes\n",
121 				 fp->iface, fp->altsetting,
122 				 sample_width, sample_bytes);
123 			break;
124 		}
125 	}
126 	if (format & (1 << UAC_FORMAT_TYPE_I_PCM8)) {
127 		/* Dallas DS4201 workaround: it advertises U8 format, but really
128 		   supports S8. */
129 		if (chip->usb_id == USB_ID(0x04fa, 0x4201))
130 			pcm_formats |= SNDRV_PCM_FMTBIT_S8;
131 		else
132 			pcm_formats |= SNDRV_PCM_FMTBIT_U8;
133 	}
134 	if (format & (1 << UAC_FORMAT_TYPE_I_IEEE_FLOAT)) {
135 		pcm_formats |= SNDRV_PCM_FMTBIT_FLOAT_LE;
136 	}
137 	if (format & (1 << UAC_FORMAT_TYPE_I_ALAW)) {
138 		pcm_formats |= SNDRV_PCM_FMTBIT_A_LAW;
139 	}
140 	if (format & (1 << UAC_FORMAT_TYPE_I_MULAW)) {
141 		pcm_formats |= SNDRV_PCM_FMTBIT_MU_LAW;
142 	}
143 	if (format & ~0x3f) {
144 		usb_audio_info(chip,
145 			 "%u:%d : unsupported format bits %#llx\n",
146 			 fp->iface, fp->altsetting, format);
147 	}
148 
149 	pcm_formats |= snd_usb_interface_dsd_format_quirks(chip, fp, sample_bytes);
150 
151 	return pcm_formats;
152 }
153 
154 static int set_fixed_rate(struct audioformat *fp, int rate, int rate_bits)
155 {
156 	kfree(fp->rate_table);
157 	fp->rate_table = kmalloc(sizeof(int), GFP_KERNEL);
158 	if (!fp->rate_table)
159 		return -ENOMEM;
160 	fp->nr_rates = 1;
161 	fp->rate_min = rate;
162 	fp->rate_max = rate;
163 	fp->rates = rate_bits;
164 	fp->rate_table[0] = rate;
165 	return 0;
166 }
167 
168 /*
169  * parse the format descriptor and stores the possible sample rates
170  * on the audioformat table (audio class v1).
171  *
172  * @dev: usb device
173  * @fp: audioformat record
174  * @fmt: the format descriptor
175  * @offset: the start offset of descriptor pointing the rate type
176  *          (7 for type I and II, 8 for type II)
177  */
178 static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audioformat *fp,
179 				       unsigned char *fmt, int offset)
180 {
181 	int nr_rates = fmt[offset];
182 
183 	if (fmt[0] < offset + 1 + 3 * (nr_rates ? nr_rates : 2)) {
184 		usb_audio_err(chip,
185 			"%u:%d : invalid UAC_FORMAT_TYPE desc\n",
186 			fp->iface, fp->altsetting);
187 		return -EINVAL;
188 	}
189 
190 	if (nr_rates) {
191 		/*
192 		 * build the rate table and bitmap flags
193 		 */
194 		int r, idx;
195 
196 		fp->rate_table = kmalloc_array(nr_rates, sizeof(int),
197 					       GFP_KERNEL);
198 		if (fp->rate_table == NULL)
199 			return -ENOMEM;
200 
201 		fp->nr_rates = 0;
202 		fp->rate_min = fp->rate_max = 0;
203 		for (r = 0, idx = offset + 1; r < nr_rates; r++, idx += 3) {
204 			unsigned int rate = combine_triple(&fmt[idx]);
205 			if (!rate)
206 				continue;
207 			/* C-Media CM6501 mislabels its 96 kHz altsetting */
208 			/* Terratec Aureon 7.1 USB C-Media 6206, too */
209 			if (rate == 48000 && nr_rates == 1 &&
210 			    (chip->usb_id == USB_ID(0x0d8c, 0x0201) ||
211 			     chip->usb_id == USB_ID(0x0d8c, 0x0102) ||
212 			     chip->usb_id == USB_ID(0x0ccd, 0x00b1)) &&
213 			    fp->altsetting == 5 && fp->maxpacksize == 392)
214 				rate = 96000;
215 			/* Creative VF0420/VF0470 Live Cams report 16 kHz instead of 8kHz */
216 			if (rate == 16000 &&
217 			    (chip->usb_id == USB_ID(0x041e, 0x4064) ||
218 			     chip->usb_id == USB_ID(0x041e, 0x4068)))
219 				rate = 8000;
220 
221 			fp->rate_table[fp->nr_rates] = rate;
222 			if (!fp->rate_min || rate < fp->rate_min)
223 				fp->rate_min = rate;
224 			if (!fp->rate_max || rate > fp->rate_max)
225 				fp->rate_max = rate;
226 			fp->rates |= snd_pcm_rate_to_rate_bit(rate);
227 			fp->nr_rates++;
228 		}
229 		if (!fp->nr_rates) {
230 			hwc_debug("All rates were zero. Skipping format!\n");
231 			return -EINVAL;
232 		}
233 	} else {
234 		/* continuous rates */
235 		fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
236 		fp->rate_min = combine_triple(&fmt[offset + 1]);
237 		fp->rate_max = combine_triple(&fmt[offset + 4]);
238 	}
239 
240 	/* Jabra Evolve 65 headset */
241 	if (chip->usb_id == USB_ID(0x0b0e, 0x030b)) {
242 		/* only 48kHz for playback while keeping 16kHz for capture */
243 		if (fp->nr_rates != 1)
244 			return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
245 	}
246 
247 	return 0;
248 }
249 
250 
251 /*
252  * Presonus Studio 1810c supports a limited set of sampling
253  * rates per altsetting but reports the full set each time.
254  * If we don't filter out the unsupported rates and attempt
255  * to configure the card, it will hang refusing to do any
256  * further audio I/O until a hard reset is performed.
257  *
258  * The list of supported rates per altsetting (set of available
259  * I/O channels) is described in the owner's manual, section 2.2.
260  */
261 static bool s1810c_valid_sample_rate(struct audioformat *fp,
262 				     unsigned int rate)
263 {
264 	switch (fp->altsetting) {
265 	case 1:
266 		/* All ADAT ports available */
267 		return rate <= 48000;
268 	case 2:
269 		/* Half of ADAT ports available */
270 		return (rate == 88200 || rate == 96000);
271 	case 3:
272 		/* Analog I/O only (no S/PDIF nor ADAT) */
273 		return rate >= 176400;
274 	default:
275 		return false;
276 	}
277 	return false;
278 }
279 
280 /*
281  * Many Focusrite devices supports a limited set of sampling rates per
282  * altsetting. Maximum rate is exposed in the last 4 bytes of Format Type
283  * descriptor which has a non-standard bLength = 10.
284  */
285 static bool focusrite_valid_sample_rate(struct snd_usb_audio *chip,
286 					struct audioformat *fp,
287 					unsigned int rate)
288 {
289 	struct usb_interface *iface;
290 	struct usb_host_interface *alts;
291 	unsigned char *fmt;
292 	unsigned int max_rate;
293 
294 	iface = usb_ifnum_to_if(chip->dev, fp->iface);
295 	if (!iface)
296 		return true;
297 
298 	alts = &iface->altsetting[fp->altset_idx];
299 	fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,
300 				      NULL, UAC_FORMAT_TYPE);
301 	if (!fmt)
302 		return true;
303 
304 	if (fmt[0] == 10) { /* bLength */
305 		max_rate = combine_quad(&fmt[6]);
306 
307 		/* Validate max rate */
308 		if (max_rate != 48000 &&
309 		    max_rate != 96000 &&
310 		    max_rate != 192000 &&
311 		    max_rate != 384000) {
312 
313 			usb_audio_info(chip,
314 				"%u:%d : unexpected max rate: %u\n",
315 				fp->iface, fp->altsetting, max_rate);
316 
317 			return true;
318 		}
319 
320 		return rate <= max_rate;
321 	}
322 
323 	return true;
324 }
325 
326 /*
327  * Helper function to walk the array of sample rate triplets reported by
328  * the device. The problem is that we need to parse whole array first to
329  * get to know how many sample rates we have to expect.
330  * Then fp->rate_table can be allocated and filled.
331  */
332 static int parse_uac2_sample_rate_range(struct snd_usb_audio *chip,
333 					struct audioformat *fp, int nr_triplets,
334 					const unsigned char *data)
335 {
336 	int i, nr_rates = 0;
337 
338 	fp->rates = fp->rate_min = fp->rate_max = 0;
339 
340 	for (i = 0; i < nr_triplets; i++) {
341 		int min = combine_quad(&data[2 + 12 * i]);
342 		int max = combine_quad(&data[6 + 12 * i]);
343 		int res = combine_quad(&data[10 + 12 * i]);
344 		unsigned int rate;
345 
346 		if ((max < 0) || (min < 0) || (res < 0) || (max < min))
347 			continue;
348 
349 		/*
350 		 * for ranges with res == 1, we announce a continuous sample
351 		 * rate range, and this function should return 0 for no further
352 		 * parsing.
353 		 */
354 		if (res == 1) {
355 			fp->rate_min = min;
356 			fp->rate_max = max;
357 			fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
358 			return 0;
359 		}
360 
361 		for (rate = min; rate <= max; rate += res) {
362 
363 			/* Filter out invalid rates on Presonus Studio 1810c */
364 			if (chip->usb_id == USB_ID(0x0194f, 0x010c) &&
365 			    !s1810c_valid_sample_rate(fp, rate))
366 				goto skip_rate;
367 
368 			/* Filter out invalid rates on Focusrite devices */
369 			if (USB_ID_VENDOR(chip->usb_id) == 0x1235 &&
370 			    !focusrite_valid_sample_rate(chip, fp, rate))
371 				goto skip_rate;
372 
373 			if (fp->rate_table)
374 				fp->rate_table[nr_rates] = rate;
375 			if (!fp->rate_min || rate < fp->rate_min)
376 				fp->rate_min = rate;
377 			if (!fp->rate_max || rate > fp->rate_max)
378 				fp->rate_max = rate;
379 			fp->rates |= snd_pcm_rate_to_rate_bit(rate);
380 
381 			nr_rates++;
382 			if (nr_rates >= MAX_NR_RATES) {
383 				usb_audio_err(chip, "invalid uac2 rates\n");
384 				break;
385 			}
386 
387 skip_rate:
388 			/* avoid endless loop */
389 			if (res == 0)
390 				break;
391 		}
392 	}
393 
394 	return nr_rates;
395 }
396 
397 /* Line6 Helix series and the Rode Rodecaster Pro don't support the
398  * UAC2_CS_RANGE usb function call. Return a static table of known
399  * clock rates.
400  */
401 static int line6_parse_audio_format_rates_quirk(struct snd_usb_audio *chip,
402 						struct audioformat *fp)
403 {
404 	switch (chip->usb_id) {
405 	case USB_ID(0x0e41, 0x4241): /* Line6 Helix */
406 	case USB_ID(0x0e41, 0x4242): /* Line6 Helix Rack */
407 	case USB_ID(0x0e41, 0x4244): /* Line6 Helix LT */
408 	case USB_ID(0x0e41, 0x4246): /* Line6 HX-Stomp */
409 	case USB_ID(0x0e41, 0x4247): /* Line6 Pod Go */
410 	case USB_ID(0x0e41, 0x4248): /* Line6 Helix >= fw 2.82 */
411 	case USB_ID(0x0e41, 0x4249): /* Line6 Helix Rack >= fw 2.82 */
412 	case USB_ID(0x0e41, 0x424a): /* Line6 Helix LT >= fw 2.82 */
413 	case USB_ID(0x19f7, 0x0011): /* Rode Rodecaster Pro */
414 		return set_fixed_rate(fp, 48000, SNDRV_PCM_RATE_48000);
415 	}
416 
417 	return -ENODEV;
418 }
419 
420 /* check whether the given altsetting is supported for the already set rate */
421 static bool check_valid_altsetting_v2v3(struct snd_usb_audio *chip, int iface,
422 					int altsetting)
423 {
424 	struct usb_device *dev = chip->dev;
425 	__le64 raw_data = 0;
426 	u64 data;
427 	int err;
428 
429 	/* we assume 64bit is enough for any altsettings */
430 	if (snd_BUG_ON(altsetting >= 64 - 8))
431 		return false;
432 
433 	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
434 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
435 			      UAC2_AS_VAL_ALT_SETTINGS << 8,
436 			      iface, &raw_data, sizeof(raw_data));
437 	if (err < 0)
438 		return false;
439 
440 	data = le64_to_cpu(raw_data);
441 	/* first byte contains the bitmap size */
442 	if ((data & 0xff) * 8 < altsetting)
443 		return false;
444 	if (data & (1ULL << (altsetting + 8)))
445 		return true;
446 
447 	return false;
448 }
449 
450 /*
451  * Validate each sample rate with the altsetting
452  * Rebuild the rate table if only partial values are valid
453  */
454 static int validate_sample_rate_table_v2v3(struct snd_usb_audio *chip,
455 					   struct audioformat *fp,
456 					   int clock)
457 {
458 	struct usb_device *dev = chip->dev;
459 	unsigned int *table;
460 	unsigned int nr_rates;
461 	unsigned int rate_min = 0x7fffffff;
462 	unsigned int rate_max = 0;
463 	unsigned int rates = 0;
464 	int i, err;
465 
466 	table = kcalloc(fp->nr_rates, sizeof(*table), GFP_KERNEL);
467 	if (!table)
468 		return -ENOMEM;
469 
470 	/* clear the interface altsetting at first */
471 	usb_set_interface(dev, fp->iface, 0);
472 
473 	nr_rates = 0;
474 	for (i = 0; i < fp->nr_rates; i++) {
475 		err = snd_usb_set_sample_rate_v2v3(chip, fp, clock,
476 						   fp->rate_table[i]);
477 		if (err < 0)
478 			continue;
479 
480 		if (check_valid_altsetting_v2v3(chip, fp->iface, fp->altsetting)) {
481 			table[nr_rates++] = fp->rate_table[i];
482 			if (rate_min > fp->rate_table[i])
483 				rate_min = fp->rate_table[i];
484 			if (rate_max < fp->rate_table[i])
485 				rate_max = fp->rate_table[i];
486 			rates |= snd_pcm_rate_to_rate_bit(fp->rate_table[i]);
487 		}
488 	}
489 
490 	if (!nr_rates) {
491 		usb_audio_dbg(chip,
492 			      "No valid sample rate available for %d:%d, assuming a firmware bug\n",
493 			      fp->iface, fp->altsetting);
494 		nr_rates = fp->nr_rates; /* continue as is */
495 	}
496 
497 	if (fp->nr_rates == nr_rates) {
498 		kfree(table);
499 		return 0;
500 	}
501 
502 	kfree(fp->rate_table);
503 	fp->rate_table = table;
504 	fp->nr_rates = nr_rates;
505 	fp->rate_min = rate_min;
506 	fp->rate_max = rate_max;
507 	fp->rates = rates;
508 	return 0;
509 }
510 
511 /*
512  * parse the format descriptor and stores the possible sample rates
513  * on the audioformat table (audio class v2 and v3).
514  */
515 static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
516 				       struct audioformat *fp)
517 {
518 	struct usb_device *dev = chip->dev;
519 	unsigned char tmp[2], *data;
520 	int nr_triplets, data_size, ret = 0, ret_l6;
521 	int clock = snd_usb_clock_find_source(chip, fp, false);
522 
523 	if (clock < 0) {
524 		dev_err(&dev->dev,
525 			"%s(): unable to find clock source (clock %d)\n",
526 				__func__, clock);
527 		goto err;
528 	}
529 
530 	/* get the number of sample rates first by only fetching 2 bytes */
531 	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
532 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
533 			      UAC2_CS_CONTROL_SAM_FREQ << 8,
534 			      snd_usb_ctrl_intf(chip) | (clock << 8),
535 			      tmp, sizeof(tmp));
536 
537 	if (ret < 0) {
538 		/* line6 helix devices don't support UAC2_CS_CONTROL_SAM_FREQ call */
539 		ret_l6 = line6_parse_audio_format_rates_quirk(chip, fp);
540 		if (ret_l6 == -ENODEV) {
541 			/* no line6 device found continue showing the error */
542 			dev_err(&dev->dev,
543 				"%s(): unable to retrieve number of sample rates (clock %d)\n",
544 				__func__, clock);
545 			goto err;
546 		}
547 		if (ret_l6 == 0) {
548 			dev_info(&dev->dev,
549 				"%s(): unable to retrieve number of sample rates: set it to a predefined value (clock %d).\n",
550 				__func__, clock);
551 			return 0;
552 		}
553 		ret = ret_l6;
554 		goto err;
555 	}
556 
557 	nr_triplets = (tmp[1] << 8) | tmp[0];
558 	data_size = 2 + 12 * nr_triplets;
559 	data = kzalloc(data_size, GFP_KERNEL);
560 	if (!data) {
561 		ret = -ENOMEM;
562 		goto err;
563 	}
564 
565 	/* now get the full information */
566 	ret = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_RANGE,
567 			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
568 			      UAC2_CS_CONTROL_SAM_FREQ << 8,
569 			      snd_usb_ctrl_intf(chip) | (clock << 8),
570 			      data, data_size);
571 
572 	if (ret < 0) {
573 		dev_err(&dev->dev,
574 			"%s(): unable to retrieve sample rate range (clock %d)\n",
575 				__func__, clock);
576 		ret = -EINVAL;
577 		goto err_free;
578 	}
579 
580 	/* Call the triplet parser, and make sure fp->rate_table is NULL.
581 	 * We just use the return value to know how many sample rates we
582 	 * will have to deal with. */
583 	kfree(fp->rate_table);
584 	fp->rate_table = NULL;
585 	fp->nr_rates = parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
586 
587 	if (fp->nr_rates == 0) {
588 		/* SNDRV_PCM_RATE_CONTINUOUS */
589 		ret = 0;
590 		goto err_free;
591 	}
592 
593 	fp->rate_table = kmalloc_array(fp->nr_rates, sizeof(int), GFP_KERNEL);
594 	if (!fp->rate_table) {
595 		ret = -ENOMEM;
596 		goto err_free;
597 	}
598 
599 	/* Call the triplet parser again, but this time, fp->rate_table is
600 	 * allocated, so the rates will be stored */
601 	parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
602 
603 	ret = validate_sample_rate_table_v2v3(chip, fp, clock);
604 
605 err_free:
606 	kfree(data);
607 err:
608 	return ret;
609 }
610 
611 /*
612  * parse the format type I and III descriptors
613  */
614 static int parse_audio_format_i(struct snd_usb_audio *chip,
615 				struct audioformat *fp, u64 format,
616 				void *_fmt)
617 {
618 	snd_pcm_format_t pcm_format;
619 	unsigned int fmt_type;
620 	int ret;
621 
622 	switch (fp->protocol) {
623 	default:
624 	case UAC_VERSION_1:
625 	case UAC_VERSION_2: {
626 		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
627 
628 		fmt_type = fmt->bFormatType;
629 		break;
630 	}
631 	case UAC_VERSION_3: {
632 		/* fp->fmt_type is already set in this case */
633 		fmt_type = fp->fmt_type;
634 		break;
635 	}
636 	}
637 
638 	if (fmt_type == UAC_FORMAT_TYPE_III) {
639 		/* FIXME: the format type is really IECxxx
640 		 *        but we give normal PCM format to get the existing
641 		 *        apps working...
642 		 */
643 		switch (chip->usb_id) {
644 
645 		case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
646 			if (chip->setup == 0x00 &&
647 			    fp->altsetting == 6)
648 				pcm_format = SNDRV_PCM_FORMAT_S16_BE;
649 			else
650 				pcm_format = SNDRV_PCM_FORMAT_S16_LE;
651 			break;
652 		default:
653 			pcm_format = SNDRV_PCM_FORMAT_S16_LE;
654 		}
655 		fp->formats = pcm_format_to_bits(pcm_format);
656 	} else {
657 		fp->formats = parse_audio_format_i_type(chip, fp, format, _fmt);
658 		if (!fp->formats)
659 			return -EINVAL;
660 	}
661 
662 	/* gather possible sample rates */
663 	/* audio class v1 reports possible sample rates as part of the
664 	 * proprietary class specific descriptor.
665 	 * audio class v2 uses class specific EP0 range requests for that.
666 	 */
667 	switch (fp->protocol) {
668 	default:
669 	case UAC_VERSION_1: {
670 		struct uac_format_type_i_continuous_descriptor *fmt = _fmt;
671 
672 		fp->channels = fmt->bNrChannels;
673 		ret = parse_audio_format_rates_v1(chip, fp, (unsigned char *) fmt, 7);
674 		break;
675 	}
676 	case UAC_VERSION_2:
677 	case UAC_VERSION_3: {
678 		/* fp->channels is already set in this case */
679 		ret = parse_audio_format_rates_v2v3(chip, fp);
680 		break;
681 	}
682 	}
683 
684 	if (fp->channels < 1) {
685 		usb_audio_err(chip,
686 			"%u:%d : invalid channels %d\n",
687 			fp->iface, fp->altsetting, fp->channels);
688 		return -EINVAL;
689 	}
690 
691 	return ret;
692 }
693 
694 /*
695  * parse the format type II descriptor
696  */
697 static int parse_audio_format_ii(struct snd_usb_audio *chip,
698 				 struct audioformat *fp,
699 				 u64 format, void *_fmt)
700 {
701 	int brate, framesize, ret;
702 
703 	switch (format) {
704 	case UAC_FORMAT_TYPE_II_AC3:
705 		/* FIXME: there is no AC3 format defined yet */
706 		// fp->formats = SNDRV_PCM_FMTBIT_AC3;
707 		fp->formats = SNDRV_PCM_FMTBIT_U8; /* temporary hack to receive byte streams */
708 		break;
709 	case UAC_FORMAT_TYPE_II_MPEG:
710 		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
711 		break;
712 	default:
713 		usb_audio_info(chip,
714 			 "%u:%d : unknown format tag %#llx is detected.  processed as MPEG.\n",
715 			 fp->iface, fp->altsetting, format);
716 		fp->formats = SNDRV_PCM_FMTBIT_MPEG;
717 		break;
718 	}
719 
720 	fp->channels = 1;
721 
722 	switch (fp->protocol) {
723 	default:
724 	case UAC_VERSION_1: {
725 		struct uac_format_type_ii_discrete_descriptor *fmt = _fmt;
726 		brate = le16_to_cpu(fmt->wMaxBitRate);
727 		framesize = le16_to_cpu(fmt->wSamplesPerFrame);
728 		usb_audio_info(chip, "found format II with max.bitrate = %d, frame size=%d\n", brate, framesize);
729 		fp->frame_size = framesize;
730 		ret = parse_audio_format_rates_v1(chip, fp, _fmt, 8); /* fmt[8..] sample rates */
731 		break;
732 	}
733 	case UAC_VERSION_2: {
734 		struct uac_format_type_ii_ext_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_v2v3(chip, fp);
740 		break;
741 	}
742 	}
743 
744 	return ret;
745 }
746 
747 int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
748 			       struct audioformat *fp, u64 format,
749 			       struct uac_format_type_i_continuous_descriptor *fmt,
750 			       int stream)
751 {
752 	int err;
753 
754 	switch (fmt->bFormatType) {
755 	case UAC_FORMAT_TYPE_I:
756 	case UAC_FORMAT_TYPE_III:
757 		err = parse_audio_format_i(chip, fp, format, fmt);
758 		break;
759 	case UAC_FORMAT_TYPE_II:
760 		err = parse_audio_format_ii(chip, fp, format, fmt);
761 		break;
762 	default:
763 		usb_audio_info(chip,
764 			 "%u:%d : format type %d is not supported yet\n",
765 			 fp->iface, fp->altsetting,
766 			 fmt->bFormatType);
767 		return -ENOTSUPP;
768 	}
769 	fp->fmt_type = fmt->bFormatType;
770 	if (err < 0)
771 		return err;
772 #if 1
773 	/* FIXME: temporary hack for extigy/audigy 2 nx/zs */
774 	/* extigy apparently supports sample rates other than 48k
775 	 * but not in ordinary way.  so we enable only 48k atm.
776 	 */
777 	if (chip->usb_id == USB_ID(0x041e, 0x3000) ||
778 	    chip->usb_id == USB_ID(0x041e, 0x3020) ||
779 	    chip->usb_id == USB_ID(0x041e, 0x3061)) {
780 		if (fmt->bFormatType == UAC_FORMAT_TYPE_I &&
781 		    fp->rates != SNDRV_PCM_RATE_48000 &&
782 		    fp->rates != SNDRV_PCM_RATE_96000)
783 			return -ENOTSUPP;
784 	}
785 #endif
786 	return 0;
787 }
788 
789 int snd_usb_parse_audio_format_v3(struct snd_usb_audio *chip,
790 			       struct audioformat *fp,
791 			       struct uac3_as_header_descriptor *as,
792 			       int stream)
793 {
794 	u64 format = le64_to_cpu(as->bmFormats);
795 	int err;
796 
797 	/*
798 	 * Type I format bits are D0..D6
799 	 * This test works because type IV is not supported
800 	 */
801 	if (format & 0x7f)
802 		fp->fmt_type = UAC_FORMAT_TYPE_I;
803 	else
804 		fp->fmt_type = UAC_FORMAT_TYPE_III;
805 
806 	err = parse_audio_format_i(chip, fp, format, as);
807 	if (err < 0)
808 		return err;
809 
810 	return 0;
811 }
812