xref: /linux/drivers/usb/gadget/function/f_uac1.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
2  * f_audio.c -- USB Audio class function driver
3   *
4  * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
5  * Copyright (C) 2008 Analog Devices, Inc
6  *
7  * Enter bugs at http://blackfin.uclinux.org/
8  *
9  * Licensed under the GPL-2 or later.
10  */
11 
12 #include <linux/slab.h>
13 #include <linux/kernel.h>
14 #include <linux/device.h>
15 #include <linux/atomic.h>
16 
17 #include "u_uac1.h"
18 
19 #define OUT_EP_MAX_PACKET_SIZE	200
20 static int req_buf_size = OUT_EP_MAX_PACKET_SIZE;
21 module_param(req_buf_size, int, S_IRUGO);
22 MODULE_PARM_DESC(req_buf_size, "ISO OUT endpoint request buffer size");
23 
24 static int req_count = 256;
25 module_param(req_count, int, S_IRUGO);
26 MODULE_PARM_DESC(req_count, "ISO OUT endpoint request count");
27 
28 static int audio_buf_size = 48000;
29 module_param(audio_buf_size, int, S_IRUGO);
30 MODULE_PARM_DESC(audio_buf_size, "Audio buffer size");
31 
32 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
33 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);
34 
35 /*
36  * DESCRIPTORS ... most are static, but strings and full
37  * configuration descriptors are built on demand.
38  */
39 
40 /*
41  * We have two interfaces- AudioControl and AudioStreaming
42  * TODO: only supcard playback currently
43  */
44 #define F_AUDIO_AC_INTERFACE	0
45 #define F_AUDIO_AS_INTERFACE	1
46 #define F_AUDIO_NUM_INTERFACES	2
47 
48 /* B.3.1  Standard AC Interface Descriptor */
49 static struct usb_interface_descriptor ac_interface_desc __initdata = {
50 	.bLength =		USB_DT_INTERFACE_SIZE,
51 	.bDescriptorType =	USB_DT_INTERFACE,
52 	.bNumEndpoints =	0,
53 	.bInterfaceClass =	USB_CLASS_AUDIO,
54 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
55 };
56 
57 DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);
58 
59 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
60 /* 1 input terminal, 1 output terminal and 1 feature unit */
61 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
62 	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
63 /* B.3.2  Class-Specific AC Interface Descriptor */
64 static struct uac1_ac_header_descriptor_2 ac_header_desc = {
65 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
66 	.bDescriptorType =	USB_DT_CS_INTERFACE,
67 	.bDescriptorSubtype =	UAC_HEADER,
68 	.bcdADC =		__constant_cpu_to_le16(0x0100),
69 	.wTotalLength =		__constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
70 	.bInCollection =	F_AUDIO_NUM_INTERFACES,
71 	.baInterfaceNr = {
72 		[0] =		F_AUDIO_AC_INTERFACE,
73 		[1] =		F_AUDIO_AS_INTERFACE,
74 	}
75 };
76 
77 #define INPUT_TERMINAL_ID	1
78 static struct uac_input_terminal_descriptor input_terminal_desc = {
79 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
80 	.bDescriptorType =	USB_DT_CS_INTERFACE,
81 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
82 	.bTerminalID =		INPUT_TERMINAL_ID,
83 	.wTerminalType =	UAC_TERMINAL_STREAMING,
84 	.bAssocTerminal =	0,
85 	.wChannelConfig =	0x3,
86 };
87 
88 DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
89 
90 #define FEATURE_UNIT_ID		2
91 static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
92 	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
93 	.bDescriptorType	= USB_DT_CS_INTERFACE,
94 	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
95 	.bUnitID		= FEATURE_UNIT_ID,
96 	.bSourceID		= INPUT_TERMINAL_ID,
97 	.bControlSize		= 2,
98 	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
99 };
100 
101 static struct usb_audio_control mute_control = {
102 	.list = LIST_HEAD_INIT(mute_control.list),
103 	.name = "Mute Control",
104 	.type = UAC_FU_MUTE,
105 	/* Todo: add real Mute control code */
106 	.set = generic_set_cmd,
107 	.get = generic_get_cmd,
108 };
109 
110 static struct usb_audio_control volume_control = {
111 	.list = LIST_HEAD_INIT(volume_control.list),
112 	.name = "Volume Control",
113 	.type = UAC_FU_VOLUME,
114 	/* Todo: add real Volume control code */
115 	.set = generic_set_cmd,
116 	.get = generic_get_cmd,
117 };
118 
119 static struct usb_audio_control_selector feature_unit = {
120 	.list = LIST_HEAD_INIT(feature_unit.list),
121 	.id = FEATURE_UNIT_ID,
122 	.name = "Mute & Volume Control",
123 	.type = UAC_FEATURE_UNIT,
124 	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
125 };
126 
127 #define OUTPUT_TERMINAL_ID	3
128 static struct uac1_output_terminal_descriptor output_terminal_desc = {
129 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
130 	.bDescriptorType	= USB_DT_CS_INTERFACE,
131 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
132 	.bTerminalID		= OUTPUT_TERMINAL_ID,
133 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
134 	.bAssocTerminal		= FEATURE_UNIT_ID,
135 	.bSourceID		= FEATURE_UNIT_ID,
136 };
137 
138 /* B.4.1  Standard AS Interface Descriptor */
139 static struct usb_interface_descriptor as_interface_alt_0_desc = {
140 	.bLength =		USB_DT_INTERFACE_SIZE,
141 	.bDescriptorType =	USB_DT_INTERFACE,
142 	.bAlternateSetting =	0,
143 	.bNumEndpoints =	0,
144 	.bInterfaceClass =	USB_CLASS_AUDIO,
145 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
146 };
147 
148 static struct usb_interface_descriptor as_interface_alt_1_desc = {
149 	.bLength =		USB_DT_INTERFACE_SIZE,
150 	.bDescriptorType =	USB_DT_INTERFACE,
151 	.bAlternateSetting =	1,
152 	.bNumEndpoints =	1,
153 	.bInterfaceClass =	USB_CLASS_AUDIO,
154 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
155 };
156 
157 /* B.4.2  Class-Specific AS Interface Descriptor */
158 static struct uac1_as_header_descriptor as_header_desc = {
159 	.bLength =		UAC_DT_AS_HEADER_SIZE,
160 	.bDescriptorType =	USB_DT_CS_INTERFACE,
161 	.bDescriptorSubtype =	UAC_AS_GENERAL,
162 	.bTerminalLink =	INPUT_TERMINAL_ID,
163 	.bDelay =		1,
164 	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
165 };
166 
167 DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
168 
169 static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
170 	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
171 	.bDescriptorType =	USB_DT_CS_INTERFACE,
172 	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
173 	.bFormatType =		UAC_FORMAT_TYPE_I,
174 	.bSubframeSize =	2,
175 	.bBitResolution =	16,
176 	.bSamFreqType =		1,
177 };
178 
179 /* Standard ISO OUT Endpoint Descriptor */
180 static struct usb_endpoint_descriptor as_out_ep_desc  = {
181 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
182 	.bDescriptorType =	USB_DT_ENDPOINT,
183 	.bEndpointAddress =	USB_DIR_OUT,
184 	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
185 				| USB_ENDPOINT_XFER_ISOC,
186 	.wMaxPacketSize =	__constant_cpu_to_le16(OUT_EP_MAX_PACKET_SIZE),
187 	.bInterval =		4,
188 };
189 
190 /* Class-specific AS ISO OUT Endpoint Descriptor */
191 static struct uac_iso_endpoint_descriptor as_iso_out_desc __initdata = {
192 	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
193 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
194 	.bDescriptorSubtype =	UAC_EP_GENERAL,
195 	.bmAttributes = 	1,
196 	.bLockDelayUnits =	1,
197 	.wLockDelay =		__constant_cpu_to_le16(1),
198 };
199 
200 static struct usb_descriptor_header *f_audio_desc[] __initdata = {
201 	(struct usb_descriptor_header *)&ac_interface_desc,
202 	(struct usb_descriptor_header *)&ac_header_desc,
203 
204 	(struct usb_descriptor_header *)&input_terminal_desc,
205 	(struct usb_descriptor_header *)&output_terminal_desc,
206 	(struct usb_descriptor_header *)&feature_unit_desc,
207 
208 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
209 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
210 	(struct usb_descriptor_header *)&as_header_desc,
211 
212 	(struct usb_descriptor_header *)&as_type_i_desc,
213 
214 	(struct usb_descriptor_header *)&as_out_ep_desc,
215 	(struct usb_descriptor_header *)&as_iso_out_desc,
216 	NULL,
217 };
218 
219 /*
220  * This function is an ALSA sound card following USB Audio Class Spec 1.0.
221  */
222 
223 /*-------------------------------------------------------------------------*/
224 struct f_audio_buf {
225 	u8 *buf;
226 	int actual;
227 	struct list_head list;
228 };
229 
230 static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
231 {
232 	struct f_audio_buf *copy_buf;
233 
234 	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
235 	if (!copy_buf)
236 		return ERR_PTR(-ENOMEM);
237 
238 	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
239 	if (!copy_buf->buf) {
240 		kfree(copy_buf);
241 		return ERR_PTR(-ENOMEM);
242 	}
243 
244 	return copy_buf;
245 }
246 
247 static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
248 {
249 	kfree(audio_buf->buf);
250 	kfree(audio_buf);
251 }
252 /*-------------------------------------------------------------------------*/
253 
254 struct f_audio {
255 	struct gaudio			card;
256 
257 	/* endpoints handle full and/or high speeds */
258 	struct usb_ep			*out_ep;
259 
260 	spinlock_t			lock;
261 	struct f_audio_buf *copy_buf;
262 	struct work_struct playback_work;
263 	struct list_head play_queue;
264 
265 	/* Control Set command */
266 	struct list_head cs;
267 	u8 set_cmd;
268 	struct usb_audio_control *set_con;
269 };
270 
271 static inline struct f_audio *func_to_audio(struct usb_function *f)
272 {
273 	return container_of(f, struct f_audio, card.func);
274 }
275 
276 /*-------------------------------------------------------------------------*/
277 
278 static void f_audio_playback_work(struct work_struct *data)
279 {
280 	struct f_audio *audio = container_of(data, struct f_audio,
281 					playback_work);
282 	struct f_audio_buf *play_buf;
283 
284 	spin_lock_irq(&audio->lock);
285 	if (list_empty(&audio->play_queue)) {
286 		spin_unlock_irq(&audio->lock);
287 		return;
288 	}
289 	play_buf = list_first_entry(&audio->play_queue,
290 			struct f_audio_buf, list);
291 	list_del(&play_buf->list);
292 	spin_unlock_irq(&audio->lock);
293 
294 	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
295 	f_audio_buffer_free(play_buf);
296 }
297 
298 static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
299 {
300 	struct f_audio *audio = req->context;
301 	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
302 	struct f_audio_buf *copy_buf = audio->copy_buf;
303 	int err;
304 
305 	if (!copy_buf)
306 		return -EINVAL;
307 
308 	/* Copy buffer is full, add it to the play_queue */
309 	if (audio_buf_size - copy_buf->actual < req->actual) {
310 		list_add_tail(&copy_buf->list, &audio->play_queue);
311 		schedule_work(&audio->playback_work);
312 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
313 		if (IS_ERR(copy_buf))
314 			return -ENOMEM;
315 	}
316 
317 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
318 	copy_buf->actual += req->actual;
319 	audio->copy_buf = copy_buf;
320 
321 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
322 	if (err)
323 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);
324 
325 	return 0;
326 
327 }
328 
329 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
330 {
331 	struct f_audio *audio = req->context;
332 	int status = req->status;
333 	u32 data = 0;
334 	struct usb_ep *out_ep = audio->out_ep;
335 
336 	switch (status) {
337 
338 	case 0:				/* normal completion? */
339 		if (ep == out_ep)
340 			f_audio_out_ep_complete(ep, req);
341 		else if (audio->set_con) {
342 			memcpy(&data, req->buf, req->length);
343 			audio->set_con->set(audio->set_con, audio->set_cmd,
344 					le16_to_cpu(data));
345 			audio->set_con = NULL;
346 		}
347 		break;
348 	default:
349 		break;
350 	}
351 }
352 
353 static int audio_set_intf_req(struct usb_function *f,
354 		const struct usb_ctrlrequest *ctrl)
355 {
356 	struct f_audio		*audio = func_to_audio(f);
357 	struct usb_composite_dev *cdev = f->config->cdev;
358 	struct usb_request	*req = cdev->req;
359 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
360 	u16			len = le16_to_cpu(ctrl->wLength);
361 	u16			w_value = le16_to_cpu(ctrl->wValue);
362 	u8			con_sel = (w_value >> 8) & 0xFF;
363 	u8			cmd = (ctrl->bRequest & 0x0F);
364 	struct usb_audio_control_selector *cs;
365 	struct usb_audio_control *con;
366 
367 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
368 			ctrl->bRequest, w_value, len, id);
369 
370 	list_for_each_entry(cs, &audio->cs, list) {
371 		if (cs->id == id) {
372 			list_for_each_entry(con, &cs->control, list) {
373 				if (con->type == con_sel) {
374 					audio->set_con = con;
375 					break;
376 				}
377 			}
378 			break;
379 		}
380 	}
381 
382 	audio->set_cmd = cmd;
383 	req->context = audio;
384 	req->complete = f_audio_complete;
385 
386 	return len;
387 }
388 
389 static int audio_get_intf_req(struct usb_function *f,
390 		const struct usb_ctrlrequest *ctrl)
391 {
392 	struct f_audio		*audio = func_to_audio(f);
393 	struct usb_composite_dev *cdev = f->config->cdev;
394 	struct usb_request	*req = cdev->req;
395 	int			value = -EOPNOTSUPP;
396 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
397 	u16			len = le16_to_cpu(ctrl->wLength);
398 	u16			w_value = le16_to_cpu(ctrl->wValue);
399 	u8			con_sel = (w_value >> 8) & 0xFF;
400 	u8			cmd = (ctrl->bRequest & 0x0F);
401 	struct usb_audio_control_selector *cs;
402 	struct usb_audio_control *con;
403 
404 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
405 			ctrl->bRequest, w_value, len, id);
406 
407 	list_for_each_entry(cs, &audio->cs, list) {
408 		if (cs->id == id) {
409 			list_for_each_entry(con, &cs->control, list) {
410 				if (con->type == con_sel && con->get) {
411 					value = con->get(con, cmd);
412 					break;
413 				}
414 			}
415 			break;
416 		}
417 	}
418 
419 	req->context = audio;
420 	req->complete = f_audio_complete;
421 	len = min_t(size_t, sizeof(value), len);
422 	memcpy(req->buf, &value, len);
423 
424 	return len;
425 }
426 
427 static int audio_set_endpoint_req(struct usb_function *f,
428 		const struct usb_ctrlrequest *ctrl)
429 {
430 	struct usb_composite_dev *cdev = f->config->cdev;
431 	int			value = -EOPNOTSUPP;
432 	u16			ep = le16_to_cpu(ctrl->wIndex);
433 	u16			len = le16_to_cpu(ctrl->wLength);
434 	u16			w_value = le16_to_cpu(ctrl->wValue);
435 
436 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
437 			ctrl->bRequest, w_value, len, ep);
438 
439 	switch (ctrl->bRequest) {
440 	case UAC_SET_CUR:
441 		value = len;
442 		break;
443 
444 	case UAC_SET_MIN:
445 		break;
446 
447 	case UAC_SET_MAX:
448 		break;
449 
450 	case UAC_SET_RES:
451 		break;
452 
453 	case UAC_SET_MEM:
454 		break;
455 
456 	default:
457 		break;
458 	}
459 
460 	return value;
461 }
462 
463 static int audio_get_endpoint_req(struct usb_function *f,
464 		const struct usb_ctrlrequest *ctrl)
465 {
466 	struct usb_composite_dev *cdev = f->config->cdev;
467 	int value = -EOPNOTSUPP;
468 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
469 	u16 len = le16_to_cpu(ctrl->wLength);
470 	u16 w_value = le16_to_cpu(ctrl->wValue);
471 
472 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
473 			ctrl->bRequest, w_value, len, ep);
474 
475 	switch (ctrl->bRequest) {
476 	case UAC_GET_CUR:
477 	case UAC_GET_MIN:
478 	case UAC_GET_MAX:
479 	case UAC_GET_RES:
480 		value = len;
481 		break;
482 	case UAC_GET_MEM:
483 		break;
484 	default:
485 		break;
486 	}
487 
488 	return value;
489 }
490 
491 static int
492 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
493 {
494 	struct usb_composite_dev *cdev = f->config->cdev;
495 	struct usb_request	*req = cdev->req;
496 	int			value = -EOPNOTSUPP;
497 	u16			w_index = le16_to_cpu(ctrl->wIndex);
498 	u16			w_value = le16_to_cpu(ctrl->wValue);
499 	u16			w_length = le16_to_cpu(ctrl->wLength);
500 
501 	/* composite driver infrastructure handles everything; interface
502 	 * activation uses set_alt().
503 	 */
504 	switch (ctrl->bRequestType) {
505 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
506 		value = audio_set_intf_req(f, ctrl);
507 		break;
508 
509 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
510 		value = audio_get_intf_req(f, ctrl);
511 		break;
512 
513 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
514 		value = audio_set_endpoint_req(f, ctrl);
515 		break;
516 
517 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
518 		value = audio_get_endpoint_req(f, ctrl);
519 		break;
520 
521 	default:
522 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
523 			ctrl->bRequestType, ctrl->bRequest,
524 			w_value, w_index, w_length);
525 	}
526 
527 	/* respond with data transfer or status phase? */
528 	if (value >= 0) {
529 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
530 			ctrl->bRequestType, ctrl->bRequest,
531 			w_value, w_index, w_length);
532 		req->zero = 0;
533 		req->length = value;
534 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
535 		if (value < 0)
536 			ERROR(cdev, "audio response on err %d\n", value);
537 	}
538 
539 	/* device either stalls (value < 0) or reports success */
540 	return value;
541 }
542 
543 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
544 {
545 	struct f_audio		*audio = func_to_audio(f);
546 	struct usb_composite_dev *cdev = f->config->cdev;
547 	struct usb_ep *out_ep = audio->out_ep;
548 	struct usb_request *req;
549 	int i = 0, err = 0;
550 
551 	DBG(cdev, "intf %d, alt %d\n", intf, alt);
552 
553 	if (intf == 1) {
554 		if (alt == 1) {
555 			usb_ep_enable(out_ep);
556 			out_ep->driver_data = audio;
557 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
558 			if (IS_ERR(audio->copy_buf))
559 				return -ENOMEM;
560 
561 			/*
562 			 * allocate a bunch of read buffers
563 			 * and queue them all at once.
564 			 */
565 			for (i = 0; i < req_count && err == 0; i++) {
566 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
567 				if (req) {
568 					req->buf = kzalloc(req_buf_size,
569 							GFP_ATOMIC);
570 					if (req->buf) {
571 						req->length = req_buf_size;
572 						req->context = audio;
573 						req->complete =
574 							f_audio_complete;
575 						err = usb_ep_queue(out_ep,
576 							req, GFP_ATOMIC);
577 						if (err)
578 							ERROR(cdev,
579 							"%s queue req: %d\n",
580 							out_ep->name, err);
581 					} else
582 						err = -ENOMEM;
583 				} else
584 					err = -ENOMEM;
585 			}
586 
587 		} else {
588 			struct f_audio_buf *copy_buf = audio->copy_buf;
589 			if (copy_buf) {
590 				list_add_tail(&copy_buf->list,
591 						&audio->play_queue);
592 				schedule_work(&audio->playback_work);
593 			}
594 		}
595 	}
596 
597 	return err;
598 }
599 
600 static void f_audio_disable(struct usb_function *f)
601 {
602 	return;
603 }
604 
605 /*-------------------------------------------------------------------------*/
606 
607 static void f_audio_build_desc(struct f_audio *audio)
608 {
609 	struct gaudio *card = &audio->card;
610 	u8 *sam_freq;
611 	int rate;
612 
613 	/* Set channel numbers */
614 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
615 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);
616 
617 	/* Set sample rates */
618 	rate = u_audio_get_playback_rate(card);
619 	sam_freq = as_type_i_desc.tSamFreq[0];
620 	memcpy(sam_freq, &rate, 3);
621 
622 	/* Todo: Set Sample bits and other parameters */
623 
624 	return;
625 }
626 
627 /* audio function driver setup/binding */
628 static int __init
629 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
630 {
631 	struct usb_composite_dev *cdev = c->cdev;
632 	struct f_audio		*audio = func_to_audio(f);
633 	int			status;
634 	struct usb_ep		*ep = NULL;
635 
636 	f_audio_build_desc(audio);
637 
638 	/* allocate instance-specific interface IDs, and patch descriptors */
639 	status = usb_interface_id(c, f);
640 	if (status < 0)
641 		goto fail;
642 	ac_interface_desc.bInterfaceNumber = status;
643 
644 	status = usb_interface_id(c, f);
645 	if (status < 0)
646 		goto fail;
647 	as_interface_alt_0_desc.bInterfaceNumber = status;
648 	as_interface_alt_1_desc.bInterfaceNumber = status;
649 
650 	status = -ENODEV;
651 
652 	/* allocate instance-specific endpoints */
653 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
654 	if (!ep)
655 		goto fail;
656 	audio->out_ep = ep;
657 	audio->out_ep->desc = &as_out_ep_desc;
658 	ep->driver_data = cdev;	/* claim */
659 
660 	status = -ENOMEM;
661 
662 	/* copy descriptors, and track endpoint copies */
663 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL);
664 	if (status)
665 		goto fail;
666 	return 0;
667 
668 fail:
669 	if (ep)
670 		ep->driver_data = NULL;
671 	return status;
672 }
673 
674 static void
675 f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
676 {
677 	struct f_audio		*audio = func_to_audio(f);
678 
679 	usb_free_all_descriptors(f);
680 	kfree(audio);
681 }
682 
683 /*-------------------------------------------------------------------------*/
684 
685 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
686 {
687 	con->data[cmd] = value;
688 
689 	return 0;
690 }
691 
692 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
693 {
694 	return con->data[cmd];
695 }
696 
697 /* Todo: add more control selecotor dynamically */
698 static int __init control_selector_init(struct f_audio *audio)
699 {
700 	INIT_LIST_HEAD(&audio->cs);
701 	list_add(&feature_unit.list, &audio->cs);
702 
703 	INIT_LIST_HEAD(&feature_unit.control);
704 	list_add(&mute_control.list, &feature_unit.control);
705 	list_add(&volume_control.list, &feature_unit.control);
706 
707 	volume_control.data[UAC__CUR] = 0xffc0;
708 	volume_control.data[UAC__MIN] = 0xe3a0;
709 	volume_control.data[UAC__MAX] = 0xfff0;
710 	volume_control.data[UAC__RES] = 0x0030;
711 
712 	return 0;
713 }
714 
715 /**
716  * audio_bind_config - add USB audio function to a configuration
717  * @c: the configuration to supcard the USB audio function
718  * Context: single threaded during gadget setup
719  *
720  * Returns zero on success, else negative errno.
721  */
722 static int __init audio_bind_config(struct usb_configuration *c)
723 {
724 	struct f_audio *audio;
725 	int status;
726 
727 	/* allocate and initialize one new instance */
728 	audio = kzalloc(sizeof *audio, GFP_KERNEL);
729 	if (!audio)
730 		return -ENOMEM;
731 
732 	audio->card.func.name = "g_audio";
733 	audio->card.gadget = c->cdev->gadget;
734 
735 	INIT_LIST_HEAD(&audio->play_queue);
736 	spin_lock_init(&audio->lock);
737 
738 	/* set up ASLA audio devices */
739 	status = gaudio_setup(&audio->card);
740 	if (status < 0)
741 		goto setup_fail;
742 
743 	audio->card.func.strings = audio_strings;
744 	audio->card.func.bind = f_audio_bind;
745 	audio->card.func.unbind = f_audio_unbind;
746 	audio->card.func.set_alt = f_audio_set_alt;
747 	audio->card.func.setup = f_audio_setup;
748 	audio->card.func.disable = f_audio_disable;
749 
750 	control_selector_init(audio);
751 
752 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
753 
754 	status = usb_add_function(c, &audio->card.func);
755 	if (status)
756 		goto add_fail;
757 
758 	INFO(c->cdev, "audio_buf_size %d, req_buf_size %d, req_count %d\n",
759 		audio_buf_size, req_buf_size, req_count);
760 
761 	return status;
762 
763 add_fail:
764 	gaudio_cleanup();
765 setup_fail:
766 	kfree(audio);
767 	return status;
768 }
769