xref: /linux/drivers/usb/gadget/function/f_uac1_legacy.c (revision 5fd54ace4721fc5ce2bb5aef6318fcf17f421460)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * f_audio.c -- USB Audio class function driver
4   *
5  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
6  * Copyright (C) 2008 Analog Devices, Inc
7  *
8  * Enter bugs at http://blackfin.uclinux.org/
9  *
10  * Licensed under the GPL-2 or later.
11  */
12 
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/device.h>
17 #include <linux/atomic.h>
18 
19 #include "u_uac1_legacy.h"
20 
21 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
22 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);
23 
24 /*
25  * DESCRIPTORS ... most are static, but strings and full
26  * configuration descriptors are built on demand.
27  */
28 
29 /*
30  * We have two interfaces- AudioControl and AudioStreaming
31  * TODO: only supcard playback currently
32  */
33 #define F_AUDIO_AC_INTERFACE	0
34 #define F_AUDIO_AS_INTERFACE	1
35 #define F_AUDIO_NUM_INTERFACES	1
36 
37 /* B.3.1  Standard AC Interface Descriptor */
38 static struct usb_interface_descriptor ac_interface_desc = {
39 	.bLength =		USB_DT_INTERFACE_SIZE,
40 	.bDescriptorType =	USB_DT_INTERFACE,
41 	.bNumEndpoints =	0,
42 	.bInterfaceClass =	USB_CLASS_AUDIO,
43 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
44 };
45 
46 /*
47  * The number of AudioStreaming and MIDIStreaming interfaces
48  * in the Audio Interface Collection
49  */
50 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
51 
52 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
53 /* 1 input terminal, 1 output terminal and 1 feature unit */
54 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
55 	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
56 /* B.3.2  Class-Specific AC Interface Descriptor */
57 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
58 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
59 	.bDescriptorType =	USB_DT_CS_INTERFACE,
60 	.bDescriptorSubtype =	UAC_HEADER,
61 	.bcdADC =		__constant_cpu_to_le16(0x0100),
62 	.wTotalLength =		__constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
63 	.bInCollection =	F_AUDIO_NUM_INTERFACES,
64 	.baInterfaceNr = {
65 	/* Interface number of the first AudioStream interface */
66 		[0] =		1,
67 	}
68 };
69 
70 #define INPUT_TERMINAL_ID	1
71 static struct uac_input_terminal_descriptor input_terminal_desc = {
72 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
73 	.bDescriptorType =	USB_DT_CS_INTERFACE,
74 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
75 	.bTerminalID =		INPUT_TERMINAL_ID,
76 	.wTerminalType =	UAC_TERMINAL_STREAMING,
77 	.bAssocTerminal =	0,
78 	.wChannelConfig =	0x3,
79 };
80 
81 DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
82 
83 #define FEATURE_UNIT_ID		2
84 static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
85 	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
86 	.bDescriptorType	= USB_DT_CS_INTERFACE,
87 	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
88 	.bUnitID		= FEATURE_UNIT_ID,
89 	.bSourceID		= INPUT_TERMINAL_ID,
90 	.bControlSize		= 2,
91 	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
92 };
93 
94 static struct usb_audio_control mute_control = {
95 	.list = LIST_HEAD_INIT(mute_control.list),
96 	.name = "Mute Control",
97 	.type = UAC_FU_MUTE,
98 	/* Todo: add real Mute control code */
99 	.set = generic_set_cmd,
100 	.get = generic_get_cmd,
101 };
102 
103 static struct usb_audio_control volume_control = {
104 	.list = LIST_HEAD_INIT(volume_control.list),
105 	.name = "Volume Control",
106 	.type = UAC_FU_VOLUME,
107 	/* Todo: add real Volume control code */
108 	.set = generic_set_cmd,
109 	.get = generic_get_cmd,
110 };
111 
112 static struct usb_audio_control_selector feature_unit = {
113 	.list = LIST_HEAD_INIT(feature_unit.list),
114 	.id = FEATURE_UNIT_ID,
115 	.name = "Mute & Volume Control",
116 	.type = UAC_FEATURE_UNIT,
117 	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
118 };
119 
120 #define OUTPUT_TERMINAL_ID	3
121 static struct uac1_output_terminal_descriptor output_terminal_desc = {
122 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
123 	.bDescriptorType	= USB_DT_CS_INTERFACE,
124 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
125 	.bTerminalID		= OUTPUT_TERMINAL_ID,
126 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
127 	.bAssocTerminal		= FEATURE_UNIT_ID,
128 	.bSourceID		= FEATURE_UNIT_ID,
129 };
130 
131 /* B.4.1  Standard AS Interface Descriptor */
132 static struct usb_interface_descriptor as_interface_alt_0_desc = {
133 	.bLength =		USB_DT_INTERFACE_SIZE,
134 	.bDescriptorType =	USB_DT_INTERFACE,
135 	.bAlternateSetting =	0,
136 	.bNumEndpoints =	0,
137 	.bInterfaceClass =	USB_CLASS_AUDIO,
138 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
139 };
140 
141 static struct usb_interface_descriptor as_interface_alt_1_desc = {
142 	.bLength =		USB_DT_INTERFACE_SIZE,
143 	.bDescriptorType =	USB_DT_INTERFACE,
144 	.bAlternateSetting =	1,
145 	.bNumEndpoints =	1,
146 	.bInterfaceClass =	USB_CLASS_AUDIO,
147 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
148 };
149 
150 /* B.4.2  Class-Specific AS Interface Descriptor */
151 static struct uac1_as_header_descriptor as_header_desc = {
152 	.bLength =		UAC_DT_AS_HEADER_SIZE,
153 	.bDescriptorType =	USB_DT_CS_INTERFACE,
154 	.bDescriptorSubtype =	UAC_AS_GENERAL,
155 	.bTerminalLink =	INPUT_TERMINAL_ID,
156 	.bDelay =		1,
157 	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
158 };
159 
160 DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
161 
162 static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
163 	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
164 	.bDescriptorType =	USB_DT_CS_INTERFACE,
165 	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
166 	.bFormatType =		UAC_FORMAT_TYPE_I,
167 	.bSubframeSize =	2,
168 	.bBitResolution =	16,
169 	.bSamFreqType =		1,
170 };
171 
172 /* Standard ISO OUT Endpoint Descriptor */
173 static struct usb_endpoint_descriptor as_out_ep_desc  = {
174 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
175 	.bDescriptorType =	USB_DT_ENDPOINT,
176 	.bEndpointAddress =	USB_DIR_OUT,
177 	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
178 				| USB_ENDPOINT_XFER_ISOC,
179 	.wMaxPacketSize	=	cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
180 	.bInterval =		4,
181 };
182 
183 /* Class-specific AS ISO OUT Endpoint Descriptor */
184 static struct uac_iso_endpoint_descriptor as_iso_out_desc = {
185 	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
186 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
187 	.bDescriptorSubtype =	UAC_EP_GENERAL,
188 	.bmAttributes = 	1,
189 	.bLockDelayUnits =	1,
190 	.wLockDelay =		__constant_cpu_to_le16(1),
191 };
192 
193 static struct usb_descriptor_header *f_audio_desc[] = {
194 	(struct usb_descriptor_header *)&ac_interface_desc,
195 	(struct usb_descriptor_header *)&ac_header_desc,
196 
197 	(struct usb_descriptor_header *)&input_terminal_desc,
198 	(struct usb_descriptor_header *)&output_terminal_desc,
199 	(struct usb_descriptor_header *)&feature_unit_desc,
200 
201 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
202 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
203 	(struct usb_descriptor_header *)&as_header_desc,
204 
205 	(struct usb_descriptor_header *)&as_type_i_desc,
206 
207 	(struct usb_descriptor_header *)&as_out_ep_desc,
208 	(struct usb_descriptor_header *)&as_iso_out_desc,
209 	NULL,
210 };
211 
212 enum {
213 	STR_AC_IF,
214 	STR_INPUT_TERMINAL,
215 	STR_INPUT_TERMINAL_CH_NAMES,
216 	STR_FEAT_DESC_0,
217 	STR_OUTPUT_TERMINAL,
218 	STR_AS_IF_ALT0,
219 	STR_AS_IF_ALT1,
220 };
221 
222 static struct usb_string strings_uac1[] = {
223 	[STR_AC_IF].s = "AC Interface",
224 	[STR_INPUT_TERMINAL].s = "Input terminal",
225 	[STR_INPUT_TERMINAL_CH_NAMES].s = "Channels",
226 	[STR_FEAT_DESC_0].s = "Volume control & mute",
227 	[STR_OUTPUT_TERMINAL].s = "Output terminal",
228 	[STR_AS_IF_ALT0].s = "AS Interface",
229 	[STR_AS_IF_ALT1].s = "AS Interface",
230 	{ },
231 };
232 
233 static struct usb_gadget_strings str_uac1 = {
234 	.language = 0x0409,	/* en-us */
235 	.strings = strings_uac1,
236 };
237 
238 static struct usb_gadget_strings *uac1_strings[] = {
239 	&str_uac1,
240 	NULL,
241 };
242 
243 /*
244  * This function is an ALSA sound card following USB Audio Class Spec 1.0.
245  */
246 
247 /*-------------------------------------------------------------------------*/
248 struct f_audio_buf {
249 	u8 *buf;
250 	int actual;
251 	struct list_head list;
252 };
253 
254 static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
255 {
256 	struct f_audio_buf *copy_buf;
257 
258 	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
259 	if (!copy_buf)
260 		return ERR_PTR(-ENOMEM);
261 
262 	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
263 	if (!copy_buf->buf) {
264 		kfree(copy_buf);
265 		return ERR_PTR(-ENOMEM);
266 	}
267 
268 	return copy_buf;
269 }
270 
271 static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
272 {
273 	kfree(audio_buf->buf);
274 	kfree(audio_buf);
275 }
276 /*-------------------------------------------------------------------------*/
277 
278 struct f_audio {
279 	struct gaudio			card;
280 
281 	u8 ac_intf, ac_alt;
282 	u8 as_intf, as_alt;
283 
284 	/* endpoints handle full and/or high speeds */
285 	struct usb_ep			*out_ep;
286 
287 	spinlock_t			lock;
288 	struct f_audio_buf *copy_buf;
289 	struct work_struct playback_work;
290 	struct list_head play_queue;
291 
292 	/* Control Set command */
293 	struct list_head cs;
294 	u8 set_cmd;
295 	struct usb_audio_control *set_con;
296 };
297 
298 static inline struct f_audio *func_to_audio(struct usb_function *f)
299 {
300 	return container_of(f, struct f_audio, card.func);
301 }
302 
303 /*-------------------------------------------------------------------------*/
304 
305 static void f_audio_playback_work(struct work_struct *data)
306 {
307 	struct f_audio *audio = container_of(data, struct f_audio,
308 					playback_work);
309 	struct f_audio_buf *play_buf;
310 
311 	spin_lock_irq(&audio->lock);
312 	if (list_empty(&audio->play_queue)) {
313 		spin_unlock_irq(&audio->lock);
314 		return;
315 	}
316 	play_buf = list_first_entry(&audio->play_queue,
317 			struct f_audio_buf, list);
318 	list_del(&play_buf->list);
319 	spin_unlock_irq(&audio->lock);
320 
321 	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
322 	f_audio_buffer_free(play_buf);
323 }
324 
325 static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
326 {
327 	struct f_audio *audio = req->context;
328 	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
329 	struct f_audio_buf *copy_buf = audio->copy_buf;
330 	struct f_uac1_legacy_opts *opts;
331 	int audio_buf_size;
332 	int err;
333 
334 	opts = container_of(audio->card.func.fi, struct f_uac1_legacy_opts,
335 			    func_inst);
336 	audio_buf_size = opts->audio_buf_size;
337 
338 	if (!copy_buf)
339 		return -EINVAL;
340 
341 	/* Copy buffer is full, add it to the play_queue */
342 	if (audio_buf_size - copy_buf->actual < req->actual) {
343 		list_add_tail(&copy_buf->list, &audio->play_queue);
344 		schedule_work(&audio->playback_work);
345 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
346 		if (IS_ERR(copy_buf))
347 			return -ENOMEM;
348 	}
349 
350 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
351 	copy_buf->actual += req->actual;
352 	audio->copy_buf = copy_buf;
353 
354 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
355 	if (err)
356 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);
357 
358 	return 0;
359 
360 }
361 
362 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
363 {
364 	struct f_audio *audio = req->context;
365 	int status = req->status;
366 	u32 data = 0;
367 	struct usb_ep *out_ep = audio->out_ep;
368 
369 	switch (status) {
370 
371 	case 0:				/* normal completion? */
372 		if (ep == out_ep)
373 			f_audio_out_ep_complete(ep, req);
374 		else if (audio->set_con) {
375 			memcpy(&data, req->buf, req->length);
376 			audio->set_con->set(audio->set_con, audio->set_cmd,
377 					le16_to_cpu(data));
378 			audio->set_con = NULL;
379 		}
380 		break;
381 	default:
382 		break;
383 	}
384 }
385 
386 static int audio_set_intf_req(struct usb_function *f,
387 		const struct usb_ctrlrequest *ctrl)
388 {
389 	struct f_audio		*audio = func_to_audio(f);
390 	struct usb_composite_dev *cdev = f->config->cdev;
391 	struct usb_request	*req = cdev->req;
392 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
393 	u16			len = le16_to_cpu(ctrl->wLength);
394 	u16			w_value = le16_to_cpu(ctrl->wValue);
395 	u8			con_sel = (w_value >> 8) & 0xFF;
396 	u8			cmd = (ctrl->bRequest & 0x0F);
397 	struct usb_audio_control_selector *cs;
398 	struct usb_audio_control *con;
399 
400 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
401 			ctrl->bRequest, w_value, len, id);
402 
403 	list_for_each_entry(cs, &audio->cs, list) {
404 		if (cs->id == id) {
405 			list_for_each_entry(con, &cs->control, list) {
406 				if (con->type == con_sel) {
407 					audio->set_con = con;
408 					break;
409 				}
410 			}
411 			break;
412 		}
413 	}
414 
415 	audio->set_cmd = cmd;
416 	req->context = audio;
417 	req->complete = f_audio_complete;
418 
419 	return len;
420 }
421 
422 static int audio_get_intf_req(struct usb_function *f,
423 		const struct usb_ctrlrequest *ctrl)
424 {
425 	struct f_audio		*audio = func_to_audio(f);
426 	struct usb_composite_dev *cdev = f->config->cdev;
427 	struct usb_request	*req = cdev->req;
428 	int			value = -EOPNOTSUPP;
429 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
430 	u16			len = le16_to_cpu(ctrl->wLength);
431 	u16			w_value = le16_to_cpu(ctrl->wValue);
432 	u8			con_sel = (w_value >> 8) & 0xFF;
433 	u8			cmd = (ctrl->bRequest & 0x0F);
434 	struct usb_audio_control_selector *cs;
435 	struct usb_audio_control *con;
436 
437 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
438 			ctrl->bRequest, w_value, len, id);
439 
440 	list_for_each_entry(cs, &audio->cs, list) {
441 		if (cs->id == id) {
442 			list_for_each_entry(con, &cs->control, list) {
443 				if (con->type == con_sel && con->get) {
444 					value = con->get(con, cmd);
445 					break;
446 				}
447 			}
448 			break;
449 		}
450 	}
451 
452 	req->context = audio;
453 	req->complete = f_audio_complete;
454 	len = min_t(size_t, sizeof(value), len);
455 	memcpy(req->buf, &value, len);
456 
457 	return len;
458 }
459 
460 static int audio_set_endpoint_req(struct usb_function *f,
461 		const struct usb_ctrlrequest *ctrl)
462 {
463 	struct usb_composite_dev *cdev = f->config->cdev;
464 	int			value = -EOPNOTSUPP;
465 	u16			ep = le16_to_cpu(ctrl->wIndex);
466 	u16			len = le16_to_cpu(ctrl->wLength);
467 	u16			w_value = le16_to_cpu(ctrl->wValue);
468 
469 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
470 			ctrl->bRequest, w_value, len, ep);
471 
472 	switch (ctrl->bRequest) {
473 	case UAC_SET_CUR:
474 		value = len;
475 		break;
476 
477 	case UAC_SET_MIN:
478 		break;
479 
480 	case UAC_SET_MAX:
481 		break;
482 
483 	case UAC_SET_RES:
484 		break;
485 
486 	case UAC_SET_MEM:
487 		break;
488 
489 	default:
490 		break;
491 	}
492 
493 	return value;
494 }
495 
496 static int audio_get_endpoint_req(struct usb_function *f,
497 		const struct usb_ctrlrequest *ctrl)
498 {
499 	struct usb_composite_dev *cdev = f->config->cdev;
500 	int value = -EOPNOTSUPP;
501 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
502 	u16 len = le16_to_cpu(ctrl->wLength);
503 	u16 w_value = le16_to_cpu(ctrl->wValue);
504 
505 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
506 			ctrl->bRequest, w_value, len, ep);
507 
508 	switch (ctrl->bRequest) {
509 	case UAC_GET_CUR:
510 	case UAC_GET_MIN:
511 	case UAC_GET_MAX:
512 	case UAC_GET_RES:
513 		value = len;
514 		break;
515 	case UAC_GET_MEM:
516 		break;
517 	default:
518 		break;
519 	}
520 
521 	return value;
522 }
523 
524 static int
525 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
526 {
527 	struct usb_composite_dev *cdev = f->config->cdev;
528 	struct usb_request	*req = cdev->req;
529 	int			value = -EOPNOTSUPP;
530 	u16			w_index = le16_to_cpu(ctrl->wIndex);
531 	u16			w_value = le16_to_cpu(ctrl->wValue);
532 	u16			w_length = le16_to_cpu(ctrl->wLength);
533 
534 	/* composite driver infrastructure handles everything; interface
535 	 * activation uses set_alt().
536 	 */
537 	switch (ctrl->bRequestType) {
538 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
539 		value = audio_set_intf_req(f, ctrl);
540 		break;
541 
542 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
543 		value = audio_get_intf_req(f, ctrl);
544 		break;
545 
546 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
547 		value = audio_set_endpoint_req(f, ctrl);
548 		break;
549 
550 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
551 		value = audio_get_endpoint_req(f, ctrl);
552 		break;
553 
554 	default:
555 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
556 			ctrl->bRequestType, ctrl->bRequest,
557 			w_value, w_index, w_length);
558 	}
559 
560 	/* respond with data transfer or status phase? */
561 	if (value >= 0) {
562 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
563 			ctrl->bRequestType, ctrl->bRequest,
564 			w_value, w_index, w_length);
565 		req->zero = 0;
566 		req->length = value;
567 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
568 		if (value < 0)
569 			ERROR(cdev, "audio response on err %d\n", value);
570 	}
571 
572 	/* device either stalls (value < 0) or reports success */
573 	return value;
574 }
575 
576 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
577 {
578 	struct f_audio		*audio = func_to_audio(f);
579 	struct usb_composite_dev *cdev = f->config->cdev;
580 	struct usb_ep *out_ep = audio->out_ep;
581 	struct usb_request *req;
582 	struct f_uac1_legacy_opts *opts;
583 	int req_buf_size, req_count, audio_buf_size;
584 	int i = 0, err = 0;
585 
586 	DBG(cdev, "intf %d, alt %d\n", intf, alt);
587 
588 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
589 	req_buf_size = opts->req_buf_size;
590 	req_count = opts->req_count;
591 	audio_buf_size = opts->audio_buf_size;
592 
593 	/* No i/f has more than 2 alt settings */
594 	if (alt > 1) {
595 		ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
596 		return -EINVAL;
597 	}
598 
599 	if (intf == audio->ac_intf) {
600 		/* Control I/f has only 1 AltSetting - 0 */
601 		if (alt) {
602 			ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
603 			return -EINVAL;
604 		}
605 		return 0;
606 	} else if (intf == audio->as_intf) {
607 		if (alt == 1) {
608 			err = config_ep_by_speed(cdev->gadget, f, out_ep);
609 			if (err)
610 				return err;
611 
612 			usb_ep_enable(out_ep);
613 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
614 			if (IS_ERR(audio->copy_buf))
615 				return -ENOMEM;
616 
617 			/*
618 			 * allocate a bunch of read buffers
619 			 * and queue them all at once.
620 			 */
621 			for (i = 0; i < req_count && err == 0; i++) {
622 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
623 				if (req) {
624 					req->buf = kzalloc(req_buf_size,
625 							GFP_ATOMIC);
626 					if (req->buf) {
627 						req->length = req_buf_size;
628 						req->context = audio;
629 						req->complete =
630 							f_audio_complete;
631 						err = usb_ep_queue(out_ep,
632 							req, GFP_ATOMIC);
633 						if (err)
634 							ERROR(cdev,
635 							"%s queue req: %d\n",
636 							out_ep->name, err);
637 					} else
638 						err = -ENOMEM;
639 				} else
640 					err = -ENOMEM;
641 			}
642 
643 		} else {
644 			struct f_audio_buf *copy_buf = audio->copy_buf;
645 			if (copy_buf) {
646 				list_add_tail(&copy_buf->list,
647 						&audio->play_queue);
648 				schedule_work(&audio->playback_work);
649 			}
650 		}
651 		audio->as_alt = alt;
652 	}
653 
654 	return err;
655 }
656 
657 static int f_audio_get_alt(struct usb_function *f, unsigned intf)
658 {
659 	struct f_audio		*audio = func_to_audio(f);
660 	struct usb_composite_dev *cdev = f->config->cdev;
661 
662 	if (intf == audio->ac_intf)
663 		return audio->ac_alt;
664 	else if (intf == audio->as_intf)
665 		return audio->as_alt;
666 	else
667 		ERROR(cdev, "%s:%d Invalid Interface %d!\n",
668 		      __func__, __LINE__, intf);
669 
670 	return -EINVAL;
671 }
672 
673 static void f_audio_disable(struct usb_function *f)
674 {
675 	return;
676 }
677 
678 /*-------------------------------------------------------------------------*/
679 
680 static void f_audio_build_desc(struct f_audio *audio)
681 {
682 	struct gaudio *card = &audio->card;
683 	u8 *sam_freq;
684 	int rate;
685 
686 	/* Set channel numbers */
687 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
688 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);
689 
690 	/* Set sample rates */
691 	rate = u_audio_get_playback_rate(card);
692 	sam_freq = as_type_i_desc.tSamFreq[0];
693 	memcpy(sam_freq, &rate, 3);
694 
695 	/* Todo: Set Sample bits and other parameters */
696 
697 	return;
698 }
699 
700 /* audio function driver setup/binding */
701 static int
702 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
703 {
704 	struct usb_composite_dev *cdev = c->cdev;
705 	struct f_audio		*audio = func_to_audio(f);
706 	struct usb_string	*us;
707 	int			status;
708 	struct usb_ep		*ep = NULL;
709 	struct f_uac1_legacy_opts	*audio_opts;
710 
711 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
712 	audio->card.gadget = c->cdev->gadget;
713 	/* set up ASLA audio devices */
714 	if (!audio_opts->bound) {
715 		status = gaudio_setup(&audio->card);
716 		if (status < 0)
717 			return status;
718 		audio_opts->bound = true;
719 	}
720 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
721 	if (IS_ERR(us))
722 		return PTR_ERR(us);
723 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
724 	input_terminal_desc.iTerminal = us[STR_INPUT_TERMINAL].id;
725 	input_terminal_desc.iChannelNames = us[STR_INPUT_TERMINAL_CH_NAMES].id;
726 	feature_unit_desc.iFeature = us[STR_FEAT_DESC_0].id;
727 	output_terminal_desc.iTerminal = us[STR_OUTPUT_TERMINAL].id;
728 	as_interface_alt_0_desc.iInterface = us[STR_AS_IF_ALT0].id;
729 	as_interface_alt_1_desc.iInterface = us[STR_AS_IF_ALT1].id;
730 
731 
732 	f_audio_build_desc(audio);
733 
734 	/* allocate instance-specific interface IDs, and patch descriptors */
735 	status = usb_interface_id(c, f);
736 	if (status < 0)
737 		goto fail;
738 	ac_interface_desc.bInterfaceNumber = status;
739 	audio->ac_intf = status;
740 	audio->ac_alt = 0;
741 
742 	status = usb_interface_id(c, f);
743 	if (status < 0)
744 		goto fail;
745 	as_interface_alt_0_desc.bInterfaceNumber = status;
746 	as_interface_alt_1_desc.bInterfaceNumber = status;
747 	audio->as_intf = status;
748 	audio->as_alt = 0;
749 
750 	status = -ENODEV;
751 
752 	/* allocate instance-specific endpoints */
753 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
754 	if (!ep)
755 		goto fail;
756 	audio->out_ep = ep;
757 	audio->out_ep->desc = &as_out_ep_desc;
758 
759 	status = -ENOMEM;
760 
761 	/* copy descriptors, and track endpoint copies */
762 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
763 					NULL);
764 	if (status)
765 		goto fail;
766 	return 0;
767 
768 fail:
769 	gaudio_cleanup(&audio->card);
770 	return status;
771 }
772 
773 /*-------------------------------------------------------------------------*/
774 
775 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
776 {
777 	con->data[cmd] = value;
778 
779 	return 0;
780 }
781 
782 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
783 {
784 	return con->data[cmd];
785 }
786 
787 /* Todo: add more control selecotor dynamically */
788 static int control_selector_init(struct f_audio *audio)
789 {
790 	INIT_LIST_HEAD(&audio->cs);
791 	list_add(&feature_unit.list, &audio->cs);
792 
793 	INIT_LIST_HEAD(&feature_unit.control);
794 	list_add(&mute_control.list, &feature_unit.control);
795 	list_add(&volume_control.list, &feature_unit.control);
796 
797 	volume_control.data[UAC__CUR] = 0xffc0;
798 	volume_control.data[UAC__MIN] = 0xe3a0;
799 	volume_control.data[UAC__MAX] = 0xfff0;
800 	volume_control.data[UAC__RES] = 0x0030;
801 
802 	return 0;
803 }
804 
805 static inline
806 struct f_uac1_legacy_opts *to_f_uac1_opts(struct config_item *item)
807 {
808 	return container_of(to_config_group(item), struct f_uac1_legacy_opts,
809 			    func_inst.group);
810 }
811 
812 static void f_uac1_attr_release(struct config_item *item)
813 {
814 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);
815 
816 	usb_put_function_instance(&opts->func_inst);
817 }
818 
819 static struct configfs_item_operations f_uac1_item_ops = {
820 	.release	= f_uac1_attr_release,
821 };
822 
823 #define UAC1_INT_ATTRIBUTE(name)					\
824 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
825 					 char *page)			\
826 {									\
827 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
828 	int result;							\
829 									\
830 	mutex_lock(&opts->lock);					\
831 	result = sprintf(page, "%u\n", opts->name);			\
832 	mutex_unlock(&opts->lock);					\
833 									\
834 	return result;							\
835 }									\
836 									\
837 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,		\
838 					  const char *page, size_t len)	\
839 {									\
840 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
841 	int ret;							\
842 	u32 num;							\
843 									\
844 	mutex_lock(&opts->lock);					\
845 	if (opts->refcnt) {						\
846 		ret = -EBUSY;						\
847 		goto end;						\
848 	}								\
849 									\
850 	ret = kstrtou32(page, 0, &num);					\
851 	if (ret)							\
852 		goto end;						\
853 									\
854 	opts->name = num;						\
855 	ret = len;							\
856 									\
857 end:									\
858 	mutex_unlock(&opts->lock);					\
859 	return ret;							\
860 }									\
861 									\
862 CONFIGFS_ATTR(f_uac1_opts_, name)
863 
864 UAC1_INT_ATTRIBUTE(req_buf_size);
865 UAC1_INT_ATTRIBUTE(req_count);
866 UAC1_INT_ATTRIBUTE(audio_buf_size);
867 
868 #define UAC1_STR_ATTRIBUTE(name)					\
869 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
870 					 char *page)			\
871 {									\
872 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
873 	int result;							\
874 									\
875 	mutex_lock(&opts->lock);					\
876 	result = sprintf(page, "%s\n", opts->name);			\
877 	mutex_unlock(&opts->lock);					\
878 									\
879 	return result;							\
880 }									\
881 									\
882 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,	\
883 					  const char *page, size_t len)	\
884 {									\
885 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
886 	int ret = -EBUSY;						\
887 	char *tmp;							\
888 									\
889 	mutex_lock(&opts->lock);					\
890 	if (opts->refcnt)						\
891 		goto end;						\
892 									\
893 	tmp = kstrndup(page, len, GFP_KERNEL);				\
894 	if (tmp) {							\
895 		ret = -ENOMEM;						\
896 		goto end;						\
897 	}								\
898 	if (opts->name##_alloc)						\
899 		kfree(opts->name);					\
900 	opts->name##_alloc = true;					\
901 	opts->name = tmp;						\
902 	ret = len;							\
903 									\
904 end:									\
905 	mutex_unlock(&opts->lock);					\
906 	return ret;							\
907 }									\
908 									\
909 CONFIGFS_ATTR(f_uac1_opts_, name)
910 
911 UAC1_STR_ATTRIBUTE(fn_play);
912 UAC1_STR_ATTRIBUTE(fn_cap);
913 UAC1_STR_ATTRIBUTE(fn_cntl);
914 
915 static struct configfs_attribute *f_uac1_attrs[] = {
916 	&f_uac1_opts_attr_req_buf_size,
917 	&f_uac1_opts_attr_req_count,
918 	&f_uac1_opts_attr_audio_buf_size,
919 	&f_uac1_opts_attr_fn_play,
920 	&f_uac1_opts_attr_fn_cap,
921 	&f_uac1_opts_attr_fn_cntl,
922 	NULL,
923 };
924 
925 static struct config_item_type f_uac1_func_type = {
926 	.ct_item_ops	= &f_uac1_item_ops,
927 	.ct_attrs	= f_uac1_attrs,
928 	.ct_owner	= THIS_MODULE,
929 };
930 
931 static void f_audio_free_inst(struct usb_function_instance *f)
932 {
933 	struct f_uac1_legacy_opts *opts;
934 
935 	opts = container_of(f, struct f_uac1_legacy_opts, func_inst);
936 	if (opts->fn_play_alloc)
937 		kfree(opts->fn_play);
938 	if (opts->fn_cap_alloc)
939 		kfree(opts->fn_cap);
940 	if (opts->fn_cntl_alloc)
941 		kfree(opts->fn_cntl);
942 	kfree(opts);
943 }
944 
945 static struct usb_function_instance *f_audio_alloc_inst(void)
946 {
947 	struct f_uac1_legacy_opts *opts;
948 
949 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
950 	if (!opts)
951 		return ERR_PTR(-ENOMEM);
952 
953 	mutex_init(&opts->lock);
954 	opts->func_inst.free_func_inst = f_audio_free_inst;
955 
956 	config_group_init_type_name(&opts->func_inst.group, "",
957 				    &f_uac1_func_type);
958 
959 	opts->req_buf_size = UAC1_OUT_EP_MAX_PACKET_SIZE;
960 	opts->req_count = UAC1_REQ_COUNT;
961 	opts->audio_buf_size = UAC1_AUDIO_BUF_SIZE;
962 	opts->fn_play = FILE_PCM_PLAYBACK;
963 	opts->fn_cap = FILE_PCM_CAPTURE;
964 	opts->fn_cntl = FILE_CONTROL;
965 	return &opts->func_inst;
966 }
967 
968 static void f_audio_free(struct usb_function *f)
969 {
970 	struct f_audio *audio = func_to_audio(f);
971 	struct f_uac1_legacy_opts *opts;
972 
973 	gaudio_cleanup(&audio->card);
974 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
975 	kfree(audio);
976 	mutex_lock(&opts->lock);
977 	--opts->refcnt;
978 	mutex_unlock(&opts->lock);
979 }
980 
981 static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
982 {
983 	usb_free_all_descriptors(f);
984 }
985 
986 static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
987 {
988 	struct f_audio *audio;
989 	struct f_uac1_legacy_opts *opts;
990 
991 	/* allocate and initialize one new instance */
992 	audio = kzalloc(sizeof(*audio), GFP_KERNEL);
993 	if (!audio)
994 		return ERR_PTR(-ENOMEM);
995 
996 	audio->card.func.name = "g_audio";
997 
998 	opts = container_of(fi, struct f_uac1_legacy_opts, func_inst);
999 	mutex_lock(&opts->lock);
1000 	++opts->refcnt;
1001 	mutex_unlock(&opts->lock);
1002 	INIT_LIST_HEAD(&audio->play_queue);
1003 	spin_lock_init(&audio->lock);
1004 
1005 	audio->card.func.bind = f_audio_bind;
1006 	audio->card.func.unbind = f_audio_unbind;
1007 	audio->card.func.set_alt = f_audio_set_alt;
1008 	audio->card.func.get_alt = f_audio_get_alt;
1009 	audio->card.func.setup = f_audio_setup;
1010 	audio->card.func.disable = f_audio_disable;
1011 	audio->card.func.free_func = f_audio_free;
1012 
1013 	control_selector_init(audio);
1014 
1015 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
1016 
1017 	return &audio->card.func;
1018 }
1019 
1020 DECLARE_USB_FUNCTION_INIT(uac1_legacy, f_audio_alloc_inst, f_audio_alloc);
1021 MODULE_LICENSE("GPL");
1022 MODULE_AUTHOR("Bryan Wu");
1023