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/module.h>
15 #include <linux/device.h>
16 #include <linux/atomic.h>
17 
18 #include "u_uac1.h"
19 
20 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
21 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);
22 
23 /*
24  * DESCRIPTORS ... most are static, but strings and full
25  * configuration descriptors are built on demand.
26  */
27 
28 /*
29  * We have two interfaces- AudioControl and AudioStreaming
30  * TODO: only supcard playback currently
31  */
32 #define F_AUDIO_AC_INTERFACE	0
33 #define F_AUDIO_AS_INTERFACE	1
34 #define F_AUDIO_NUM_INTERFACES	1
35 
36 /* B.3.1  Standard AC Interface Descriptor */
37 static struct usb_interface_descriptor ac_interface_desc = {
38 	.bLength =		USB_DT_INTERFACE_SIZE,
39 	.bDescriptorType =	USB_DT_INTERFACE,
40 	.bNumEndpoints =	0,
41 	.bInterfaceClass =	USB_CLASS_AUDIO,
42 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
43 };
44 
45 /*
46  * The number of AudioStreaming and MIDIStreaming interfaces
47  * in the Audio Interface Collection
48  */
49 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
50 
51 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
52 /* 1 input terminal, 1 output terminal and 1 feature unit */
53 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
54 	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
55 /* B.3.2  Class-Specific AC Interface Descriptor */
56 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
57 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
58 	.bDescriptorType =	USB_DT_CS_INTERFACE,
59 	.bDescriptorSubtype =	UAC_HEADER,
60 	.bcdADC =		__constant_cpu_to_le16(0x0100),
61 	.wTotalLength =		__constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
62 	.bInCollection =	F_AUDIO_NUM_INTERFACES,
63 	.baInterfaceNr = {
64 	/* Interface number of the first AudioStream interface */
65 		[0] =		1,
66 	}
67 };
68 
69 #define INPUT_TERMINAL_ID	1
70 static struct uac_input_terminal_descriptor input_terminal_desc = {
71 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
72 	.bDescriptorType =	USB_DT_CS_INTERFACE,
73 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
74 	.bTerminalID =		INPUT_TERMINAL_ID,
75 	.wTerminalType =	UAC_TERMINAL_STREAMING,
76 	.bAssocTerminal =	0,
77 	.wChannelConfig =	0x3,
78 };
79 
80 DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
81 
82 #define FEATURE_UNIT_ID		2
83 static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
84 	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
85 	.bDescriptorType	= USB_DT_CS_INTERFACE,
86 	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
87 	.bUnitID		= FEATURE_UNIT_ID,
88 	.bSourceID		= INPUT_TERMINAL_ID,
89 	.bControlSize		= 2,
90 	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
91 };
92 
93 static struct usb_audio_control mute_control = {
94 	.list = LIST_HEAD_INIT(mute_control.list),
95 	.name = "Mute Control",
96 	.type = UAC_FU_MUTE,
97 	/* Todo: add real Mute control code */
98 	.set = generic_set_cmd,
99 	.get = generic_get_cmd,
100 };
101 
102 static struct usb_audio_control volume_control = {
103 	.list = LIST_HEAD_INIT(volume_control.list),
104 	.name = "Volume Control",
105 	.type = UAC_FU_VOLUME,
106 	/* Todo: add real Volume control code */
107 	.set = generic_set_cmd,
108 	.get = generic_get_cmd,
109 };
110 
111 static struct usb_audio_control_selector feature_unit = {
112 	.list = LIST_HEAD_INIT(feature_unit.list),
113 	.id = FEATURE_UNIT_ID,
114 	.name = "Mute & Volume Control",
115 	.type = UAC_FEATURE_UNIT,
116 	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
117 };
118 
119 #define OUTPUT_TERMINAL_ID	3
120 static struct uac1_output_terminal_descriptor output_terminal_desc = {
121 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
122 	.bDescriptorType	= USB_DT_CS_INTERFACE,
123 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
124 	.bTerminalID		= OUTPUT_TERMINAL_ID,
125 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
126 	.bAssocTerminal		= FEATURE_UNIT_ID,
127 	.bSourceID		= FEATURE_UNIT_ID,
128 };
129 
130 /* B.4.1  Standard AS Interface Descriptor */
131 static struct usb_interface_descriptor as_interface_alt_0_desc = {
132 	.bLength =		USB_DT_INTERFACE_SIZE,
133 	.bDescriptorType =	USB_DT_INTERFACE,
134 	.bAlternateSetting =	0,
135 	.bNumEndpoints =	0,
136 	.bInterfaceClass =	USB_CLASS_AUDIO,
137 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
138 };
139 
140 static struct usb_interface_descriptor as_interface_alt_1_desc = {
141 	.bLength =		USB_DT_INTERFACE_SIZE,
142 	.bDescriptorType =	USB_DT_INTERFACE,
143 	.bAlternateSetting =	1,
144 	.bNumEndpoints =	1,
145 	.bInterfaceClass =	USB_CLASS_AUDIO,
146 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
147 };
148 
149 /* B.4.2  Class-Specific AS Interface Descriptor */
150 static struct uac1_as_header_descriptor as_header_desc = {
151 	.bLength =		UAC_DT_AS_HEADER_SIZE,
152 	.bDescriptorType =	USB_DT_CS_INTERFACE,
153 	.bDescriptorSubtype =	UAC_AS_GENERAL,
154 	.bTerminalLink =	INPUT_TERMINAL_ID,
155 	.bDelay =		1,
156 	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
157 };
158 
159 DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
160 
161 static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
162 	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
163 	.bDescriptorType =	USB_DT_CS_INTERFACE,
164 	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
165 	.bFormatType =		UAC_FORMAT_TYPE_I,
166 	.bSubframeSize =	2,
167 	.bBitResolution =	16,
168 	.bSamFreqType =		1,
169 };
170 
171 /* Standard ISO OUT Endpoint Descriptor */
172 static struct usb_endpoint_descriptor as_out_ep_desc  = {
173 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
174 	.bDescriptorType =	USB_DT_ENDPOINT,
175 	.bEndpointAddress =	USB_DIR_OUT,
176 	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
177 				| USB_ENDPOINT_XFER_ISOC,
178 	.wMaxPacketSize	=	cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
179 	.bInterval =		4,
180 };
181 
182 /* Class-specific AS ISO OUT Endpoint Descriptor */
183 static struct uac_iso_endpoint_descriptor as_iso_out_desc = {
184 	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
185 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
186 	.bDescriptorSubtype =	UAC_EP_GENERAL,
187 	.bmAttributes = 	1,
188 	.bLockDelayUnits =	1,
189 	.wLockDelay =		__constant_cpu_to_le16(1),
190 };
191 
192 static struct usb_descriptor_header *f_audio_desc[] = {
193 	(struct usb_descriptor_header *)&ac_interface_desc,
194 	(struct usb_descriptor_header *)&ac_header_desc,
195 
196 	(struct usb_descriptor_header *)&input_terminal_desc,
197 	(struct usb_descriptor_header *)&output_terminal_desc,
198 	(struct usb_descriptor_header *)&feature_unit_desc,
199 
200 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
201 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
202 	(struct usb_descriptor_header *)&as_header_desc,
203 
204 	(struct usb_descriptor_header *)&as_type_i_desc,
205 
206 	(struct usb_descriptor_header *)&as_out_ep_desc,
207 	(struct usb_descriptor_header *)&as_iso_out_desc,
208 	NULL,
209 };
210 
211 enum {
212 	STR_AC_IF,
213 	STR_INPUT_TERMINAL,
214 	STR_INPUT_TERMINAL_CH_NAMES,
215 	STR_FEAT_DESC_0,
216 	STR_OUTPUT_TERMINAL,
217 	STR_AS_IF_ALT0,
218 	STR_AS_IF_ALT1,
219 };
220 
221 static struct usb_string strings_uac1[] = {
222 	[STR_AC_IF].s = "AC Interface",
223 	[STR_INPUT_TERMINAL].s = "Input terminal",
224 	[STR_INPUT_TERMINAL_CH_NAMES].s = "Channels",
225 	[STR_FEAT_DESC_0].s = "Volume control & mute",
226 	[STR_OUTPUT_TERMINAL].s = "Output terminal",
227 	[STR_AS_IF_ALT0].s = "AS Interface",
228 	[STR_AS_IF_ALT1].s = "AS Interface",
229 	{ },
230 };
231 
232 static struct usb_gadget_strings str_uac1 = {
233 	.language = 0x0409,	/* en-us */
234 	.strings = strings_uac1,
235 };
236 
237 static struct usb_gadget_strings *uac1_strings[] = {
238 	&str_uac1,
239 	NULL,
240 };
241 
242 /*
243  * This function is an ALSA sound card following USB Audio Class Spec 1.0.
244  */
245 
246 /*-------------------------------------------------------------------------*/
247 struct f_audio_buf {
248 	u8 *buf;
249 	int actual;
250 	struct list_head list;
251 };
252 
253 static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
254 {
255 	struct f_audio_buf *copy_buf;
256 
257 	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
258 	if (!copy_buf)
259 		return ERR_PTR(-ENOMEM);
260 
261 	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
262 	if (!copy_buf->buf) {
263 		kfree(copy_buf);
264 		return ERR_PTR(-ENOMEM);
265 	}
266 
267 	return copy_buf;
268 }
269 
270 static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
271 {
272 	kfree(audio_buf->buf);
273 	kfree(audio_buf);
274 }
275 /*-------------------------------------------------------------------------*/
276 
277 struct f_audio {
278 	struct gaudio			card;
279 
280 	/* endpoints handle full and/or high speeds */
281 	struct usb_ep			*out_ep;
282 
283 	spinlock_t			lock;
284 	struct f_audio_buf *copy_buf;
285 	struct work_struct playback_work;
286 	struct list_head play_queue;
287 
288 	/* Control Set command */
289 	struct list_head cs;
290 	u8 set_cmd;
291 	struct usb_audio_control *set_con;
292 };
293 
294 static inline struct f_audio *func_to_audio(struct usb_function *f)
295 {
296 	return container_of(f, struct f_audio, card.func);
297 }
298 
299 /*-------------------------------------------------------------------------*/
300 
301 static void f_audio_playback_work(struct work_struct *data)
302 {
303 	struct f_audio *audio = container_of(data, struct f_audio,
304 					playback_work);
305 	struct f_audio_buf *play_buf;
306 
307 	spin_lock_irq(&audio->lock);
308 	if (list_empty(&audio->play_queue)) {
309 		spin_unlock_irq(&audio->lock);
310 		return;
311 	}
312 	play_buf = list_first_entry(&audio->play_queue,
313 			struct f_audio_buf, list);
314 	list_del(&play_buf->list);
315 	spin_unlock_irq(&audio->lock);
316 
317 	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
318 	f_audio_buffer_free(play_buf);
319 }
320 
321 static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
322 {
323 	struct f_audio *audio = req->context;
324 	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
325 	struct f_audio_buf *copy_buf = audio->copy_buf;
326 	struct f_uac1_opts *opts;
327 	int audio_buf_size;
328 	int err;
329 
330 	opts = container_of(audio->card.func.fi, struct f_uac1_opts,
331 			    func_inst);
332 	audio_buf_size = opts->audio_buf_size;
333 
334 	if (!copy_buf)
335 		return -EINVAL;
336 
337 	/* Copy buffer is full, add it to the play_queue */
338 	if (audio_buf_size - copy_buf->actual < req->actual) {
339 		list_add_tail(&copy_buf->list, &audio->play_queue);
340 		schedule_work(&audio->playback_work);
341 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
342 		if (IS_ERR(copy_buf))
343 			return -ENOMEM;
344 	}
345 
346 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
347 	copy_buf->actual += req->actual;
348 	audio->copy_buf = copy_buf;
349 
350 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
351 	if (err)
352 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);
353 
354 	return 0;
355 
356 }
357 
358 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
359 {
360 	struct f_audio *audio = req->context;
361 	int status = req->status;
362 	u32 data = 0;
363 	struct usb_ep *out_ep = audio->out_ep;
364 
365 	switch (status) {
366 
367 	case 0:				/* normal completion? */
368 		if (ep == out_ep)
369 			f_audio_out_ep_complete(ep, req);
370 		else if (audio->set_con) {
371 			memcpy(&data, req->buf, req->length);
372 			audio->set_con->set(audio->set_con, audio->set_cmd,
373 					le16_to_cpu(data));
374 			audio->set_con = NULL;
375 		}
376 		break;
377 	default:
378 		break;
379 	}
380 }
381 
382 static int audio_set_intf_req(struct usb_function *f,
383 		const struct usb_ctrlrequest *ctrl)
384 {
385 	struct f_audio		*audio = func_to_audio(f);
386 	struct usb_composite_dev *cdev = f->config->cdev;
387 	struct usb_request	*req = cdev->req;
388 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
389 	u16			len = le16_to_cpu(ctrl->wLength);
390 	u16			w_value = le16_to_cpu(ctrl->wValue);
391 	u8			con_sel = (w_value >> 8) & 0xFF;
392 	u8			cmd = (ctrl->bRequest & 0x0F);
393 	struct usb_audio_control_selector *cs;
394 	struct usb_audio_control *con;
395 
396 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
397 			ctrl->bRequest, w_value, len, id);
398 
399 	list_for_each_entry(cs, &audio->cs, list) {
400 		if (cs->id == id) {
401 			list_for_each_entry(con, &cs->control, list) {
402 				if (con->type == con_sel) {
403 					audio->set_con = con;
404 					break;
405 				}
406 			}
407 			break;
408 		}
409 	}
410 
411 	audio->set_cmd = cmd;
412 	req->context = audio;
413 	req->complete = f_audio_complete;
414 
415 	return len;
416 }
417 
418 static int audio_get_intf_req(struct usb_function *f,
419 		const struct usb_ctrlrequest *ctrl)
420 {
421 	struct f_audio		*audio = func_to_audio(f);
422 	struct usb_composite_dev *cdev = f->config->cdev;
423 	struct usb_request	*req = cdev->req;
424 	int			value = -EOPNOTSUPP;
425 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
426 	u16			len = le16_to_cpu(ctrl->wLength);
427 	u16			w_value = le16_to_cpu(ctrl->wValue);
428 	u8			con_sel = (w_value >> 8) & 0xFF;
429 	u8			cmd = (ctrl->bRequest & 0x0F);
430 	struct usb_audio_control_selector *cs;
431 	struct usb_audio_control *con;
432 
433 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
434 			ctrl->bRequest, w_value, len, id);
435 
436 	list_for_each_entry(cs, &audio->cs, list) {
437 		if (cs->id == id) {
438 			list_for_each_entry(con, &cs->control, list) {
439 				if (con->type == con_sel && con->get) {
440 					value = con->get(con, cmd);
441 					break;
442 				}
443 			}
444 			break;
445 		}
446 	}
447 
448 	req->context = audio;
449 	req->complete = f_audio_complete;
450 	len = min_t(size_t, sizeof(value), len);
451 	memcpy(req->buf, &value, len);
452 
453 	return len;
454 }
455 
456 static int audio_set_endpoint_req(struct usb_function *f,
457 		const struct usb_ctrlrequest *ctrl)
458 {
459 	struct usb_composite_dev *cdev = f->config->cdev;
460 	int			value = -EOPNOTSUPP;
461 	u16			ep = le16_to_cpu(ctrl->wIndex);
462 	u16			len = le16_to_cpu(ctrl->wLength);
463 	u16			w_value = le16_to_cpu(ctrl->wValue);
464 
465 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
466 			ctrl->bRequest, w_value, len, ep);
467 
468 	switch (ctrl->bRequest) {
469 	case UAC_SET_CUR:
470 		value = len;
471 		break;
472 
473 	case UAC_SET_MIN:
474 		break;
475 
476 	case UAC_SET_MAX:
477 		break;
478 
479 	case UAC_SET_RES:
480 		break;
481 
482 	case UAC_SET_MEM:
483 		break;
484 
485 	default:
486 		break;
487 	}
488 
489 	return value;
490 }
491 
492 static int audio_get_endpoint_req(struct usb_function *f,
493 		const struct usb_ctrlrequest *ctrl)
494 {
495 	struct usb_composite_dev *cdev = f->config->cdev;
496 	int value = -EOPNOTSUPP;
497 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
498 	u16 len = le16_to_cpu(ctrl->wLength);
499 	u16 w_value = le16_to_cpu(ctrl->wValue);
500 
501 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
502 			ctrl->bRequest, w_value, len, ep);
503 
504 	switch (ctrl->bRequest) {
505 	case UAC_GET_CUR:
506 	case UAC_GET_MIN:
507 	case UAC_GET_MAX:
508 	case UAC_GET_RES:
509 		value = len;
510 		break;
511 	case UAC_GET_MEM:
512 		break;
513 	default:
514 		break;
515 	}
516 
517 	return value;
518 }
519 
520 static int
521 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
522 {
523 	struct usb_composite_dev *cdev = f->config->cdev;
524 	struct usb_request	*req = cdev->req;
525 	int			value = -EOPNOTSUPP;
526 	u16			w_index = le16_to_cpu(ctrl->wIndex);
527 	u16			w_value = le16_to_cpu(ctrl->wValue);
528 	u16			w_length = le16_to_cpu(ctrl->wLength);
529 
530 	/* composite driver infrastructure handles everything; interface
531 	 * activation uses set_alt().
532 	 */
533 	switch (ctrl->bRequestType) {
534 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
535 		value = audio_set_intf_req(f, ctrl);
536 		break;
537 
538 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
539 		value = audio_get_intf_req(f, ctrl);
540 		break;
541 
542 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
543 		value = audio_set_endpoint_req(f, ctrl);
544 		break;
545 
546 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
547 		value = audio_get_endpoint_req(f, ctrl);
548 		break;
549 
550 	default:
551 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
552 			ctrl->bRequestType, ctrl->bRequest,
553 			w_value, w_index, w_length);
554 	}
555 
556 	/* respond with data transfer or status phase? */
557 	if (value >= 0) {
558 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
559 			ctrl->bRequestType, ctrl->bRequest,
560 			w_value, w_index, w_length);
561 		req->zero = 0;
562 		req->length = value;
563 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
564 		if (value < 0)
565 			ERROR(cdev, "audio response on err %d\n", value);
566 	}
567 
568 	/* device either stalls (value < 0) or reports success */
569 	return value;
570 }
571 
572 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
573 {
574 	struct f_audio		*audio = func_to_audio(f);
575 	struct usb_composite_dev *cdev = f->config->cdev;
576 	struct usb_ep *out_ep = audio->out_ep;
577 	struct usb_request *req;
578 	struct f_uac1_opts *opts;
579 	int req_buf_size, req_count, audio_buf_size;
580 	int i = 0, err = 0;
581 
582 	DBG(cdev, "intf %d, alt %d\n", intf, alt);
583 
584 	opts = container_of(f->fi, struct f_uac1_opts, func_inst);
585 	req_buf_size = opts->req_buf_size;
586 	req_count = opts->req_count;
587 	audio_buf_size = opts->audio_buf_size;
588 
589 	if (intf == 1) {
590 		if (alt == 1) {
591 			config_ep_by_speed(cdev->gadget, f, out_ep);
592 			usb_ep_enable(out_ep);
593 			out_ep->driver_data = audio;
594 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
595 			if (IS_ERR(audio->copy_buf))
596 				return -ENOMEM;
597 
598 			/*
599 			 * allocate a bunch of read buffers
600 			 * and queue them all at once.
601 			 */
602 			for (i = 0; i < req_count && err == 0; i++) {
603 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
604 				if (req) {
605 					req->buf = kzalloc(req_buf_size,
606 							GFP_ATOMIC);
607 					if (req->buf) {
608 						req->length = req_buf_size;
609 						req->context = audio;
610 						req->complete =
611 							f_audio_complete;
612 						err = usb_ep_queue(out_ep,
613 							req, GFP_ATOMIC);
614 						if (err)
615 							ERROR(cdev,
616 							"%s queue req: %d\n",
617 							out_ep->name, err);
618 					} else
619 						err = -ENOMEM;
620 				} else
621 					err = -ENOMEM;
622 			}
623 
624 		} else {
625 			struct f_audio_buf *copy_buf = audio->copy_buf;
626 			if (copy_buf) {
627 				list_add_tail(&copy_buf->list,
628 						&audio->play_queue);
629 				schedule_work(&audio->playback_work);
630 			}
631 		}
632 	}
633 
634 	return err;
635 }
636 
637 static void f_audio_disable(struct usb_function *f)
638 {
639 	return;
640 }
641 
642 /*-------------------------------------------------------------------------*/
643 
644 static void f_audio_build_desc(struct f_audio *audio)
645 {
646 	struct gaudio *card = &audio->card;
647 	u8 *sam_freq;
648 	int rate;
649 
650 	/* Set channel numbers */
651 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
652 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);
653 
654 	/* Set sample rates */
655 	rate = u_audio_get_playback_rate(card);
656 	sam_freq = as_type_i_desc.tSamFreq[0];
657 	memcpy(sam_freq, &rate, 3);
658 
659 	/* Todo: Set Sample bits and other parameters */
660 
661 	return;
662 }
663 
664 /* audio function driver setup/binding */
665 static int
666 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
667 {
668 	struct usb_composite_dev *cdev = c->cdev;
669 	struct f_audio		*audio = func_to_audio(f);
670 	struct usb_string	*us;
671 	int			status;
672 	struct usb_ep		*ep = NULL;
673 	struct f_uac1_opts	*audio_opts;
674 
675 	audio_opts = container_of(f->fi, struct f_uac1_opts, func_inst);
676 	audio->card.gadget = c->cdev->gadget;
677 	/* set up ASLA audio devices */
678 	if (!audio_opts->bound) {
679 		status = gaudio_setup(&audio->card);
680 		if (status < 0)
681 			return status;
682 		audio_opts->bound = true;
683 	}
684 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
685 	if (IS_ERR(us))
686 		return PTR_ERR(us);
687 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
688 	input_terminal_desc.iTerminal = us[STR_INPUT_TERMINAL].id;
689 	input_terminal_desc.iChannelNames = us[STR_INPUT_TERMINAL_CH_NAMES].id;
690 	feature_unit_desc.iFeature = us[STR_FEAT_DESC_0].id;
691 	output_terminal_desc.iTerminal = us[STR_OUTPUT_TERMINAL].id;
692 	as_interface_alt_0_desc.iInterface = us[STR_AS_IF_ALT0].id;
693 	as_interface_alt_1_desc.iInterface = us[STR_AS_IF_ALT1].id;
694 
695 
696 	f_audio_build_desc(audio);
697 
698 	/* allocate instance-specific interface IDs, and patch descriptors */
699 	status = usb_interface_id(c, f);
700 	if (status < 0)
701 		goto fail;
702 	ac_interface_desc.bInterfaceNumber = status;
703 
704 	status = usb_interface_id(c, f);
705 	if (status < 0)
706 		goto fail;
707 	as_interface_alt_0_desc.bInterfaceNumber = status;
708 	as_interface_alt_1_desc.bInterfaceNumber = status;
709 
710 	status = -ENODEV;
711 
712 	/* allocate instance-specific endpoints */
713 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
714 	if (!ep)
715 		goto fail;
716 	audio->out_ep = ep;
717 	audio->out_ep->desc = &as_out_ep_desc;
718 	ep->driver_data = cdev;	/* claim */
719 
720 	status = -ENOMEM;
721 
722 	/* copy descriptors, and track endpoint copies */
723 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL);
724 	if (status)
725 		goto fail;
726 	return 0;
727 
728 fail:
729 	gaudio_cleanup(&audio->card);
730 	if (ep)
731 		ep->driver_data = NULL;
732 	return status;
733 }
734 
735 /*-------------------------------------------------------------------------*/
736 
737 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
738 {
739 	con->data[cmd] = value;
740 
741 	return 0;
742 }
743 
744 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
745 {
746 	return con->data[cmd];
747 }
748 
749 /* Todo: add more control selecotor dynamically */
750 static int control_selector_init(struct f_audio *audio)
751 {
752 	INIT_LIST_HEAD(&audio->cs);
753 	list_add(&feature_unit.list, &audio->cs);
754 
755 	INIT_LIST_HEAD(&feature_unit.control);
756 	list_add(&mute_control.list, &feature_unit.control);
757 	list_add(&volume_control.list, &feature_unit.control);
758 
759 	volume_control.data[UAC__CUR] = 0xffc0;
760 	volume_control.data[UAC__MIN] = 0xe3a0;
761 	volume_control.data[UAC__MAX] = 0xfff0;
762 	volume_control.data[UAC__RES] = 0x0030;
763 
764 	return 0;
765 }
766 
767 static inline struct f_uac1_opts *to_f_uac1_opts(struct config_item *item)
768 {
769 	return container_of(to_config_group(item), struct f_uac1_opts,
770 			    func_inst.group);
771 }
772 
773 CONFIGFS_ATTR_STRUCT(f_uac1_opts);
774 CONFIGFS_ATTR_OPS(f_uac1_opts);
775 
776 static void f_uac1_attr_release(struct config_item *item)
777 {
778 	struct f_uac1_opts *opts = to_f_uac1_opts(item);
779 
780 	usb_put_function_instance(&opts->func_inst);
781 }
782 
783 static struct configfs_item_operations f_uac1_item_ops = {
784 	.release	= f_uac1_attr_release,
785 	.show_attribute	= f_uac1_opts_attr_show,
786 	.store_attribute = f_uac1_opts_attr_store,
787 };
788 
789 #define UAC1_INT_ATTRIBUTE(name)					\
790 static ssize_t f_uac1_opts_##name##_show(struct f_uac1_opts *opts,	\
791 					 char *page)			\
792 {									\
793 	int result;							\
794 									\
795 	mutex_lock(&opts->lock);					\
796 	result = sprintf(page, "%u\n", opts->name);			\
797 	mutex_unlock(&opts->lock);					\
798 									\
799 	return result;							\
800 }									\
801 									\
802 static ssize_t f_uac1_opts_##name##_store(struct f_uac1_opts *opts,	\
803 					  const char *page, size_t len)	\
804 {									\
805 	int ret;							\
806 	u32 num;							\
807 									\
808 	mutex_lock(&opts->lock);					\
809 	if (opts->refcnt) {						\
810 		ret = -EBUSY;						\
811 		goto end;						\
812 	}								\
813 									\
814 	ret = kstrtou32(page, 0, &num);					\
815 	if (ret)							\
816 		goto end;						\
817 									\
818 	opts->name = num;						\
819 	ret = len;							\
820 									\
821 end:									\
822 	mutex_unlock(&opts->lock);					\
823 	return ret;							\
824 }									\
825 									\
826 static struct f_uac1_opts_attribute f_uac1_opts_##name =		\
827 	__CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR,			\
828 			f_uac1_opts_##name##_show,			\
829 			f_uac1_opts_##name##_store)
830 
831 UAC1_INT_ATTRIBUTE(req_buf_size);
832 UAC1_INT_ATTRIBUTE(req_count);
833 UAC1_INT_ATTRIBUTE(audio_buf_size);
834 
835 #define UAC1_STR_ATTRIBUTE(name)					\
836 static ssize_t f_uac1_opts_##name##_show(struct f_uac1_opts *opts,	\
837 					 char *page)			\
838 {									\
839 	int result;							\
840 									\
841 	mutex_lock(&opts->lock);					\
842 	result = sprintf(page, "%s\n", opts->name);			\
843 	mutex_unlock(&opts->lock);					\
844 									\
845 	return result;							\
846 }									\
847 									\
848 static ssize_t f_uac1_opts_##name##_store(struct f_uac1_opts *opts,	\
849 					  const char *page, size_t len)	\
850 {									\
851 	int ret = -EBUSY;						\
852 	char *tmp;							\
853 									\
854 	mutex_lock(&opts->lock);					\
855 	if (opts->refcnt)						\
856 		goto end;						\
857 									\
858 	tmp = kstrndup(page, len, GFP_KERNEL);				\
859 	if (tmp) {							\
860 		ret = -ENOMEM;						\
861 		goto end;						\
862 	}								\
863 	if (opts->name##_alloc)						\
864 		kfree(opts->name);					\
865 	opts->name##_alloc = true;					\
866 	opts->name = tmp;						\
867 	ret = len;							\
868 									\
869 end:									\
870 	mutex_unlock(&opts->lock);					\
871 	return ret;							\
872 }									\
873 									\
874 static struct f_uac1_opts_attribute f_uac1_opts_##name =		\
875 	__CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR,			\
876 			f_uac1_opts_##name##_show,			\
877 			f_uac1_opts_##name##_store)
878 
879 UAC1_STR_ATTRIBUTE(fn_play);
880 UAC1_STR_ATTRIBUTE(fn_cap);
881 UAC1_STR_ATTRIBUTE(fn_cntl);
882 
883 static struct configfs_attribute *f_uac1_attrs[] = {
884 	&f_uac1_opts_req_buf_size.attr,
885 	&f_uac1_opts_req_count.attr,
886 	&f_uac1_opts_audio_buf_size.attr,
887 	&f_uac1_opts_fn_play.attr,
888 	&f_uac1_opts_fn_cap.attr,
889 	&f_uac1_opts_fn_cntl.attr,
890 	NULL,
891 };
892 
893 static struct config_item_type f_uac1_func_type = {
894 	.ct_item_ops	= &f_uac1_item_ops,
895 	.ct_attrs	= f_uac1_attrs,
896 	.ct_owner	= THIS_MODULE,
897 };
898 
899 static void f_audio_free_inst(struct usb_function_instance *f)
900 {
901 	struct f_uac1_opts *opts;
902 
903 	opts = container_of(f, struct f_uac1_opts, func_inst);
904 	if (opts->fn_play_alloc)
905 		kfree(opts->fn_play);
906 	if (opts->fn_cap_alloc)
907 		kfree(opts->fn_cap);
908 	if (opts->fn_cntl_alloc)
909 		kfree(opts->fn_cntl);
910 	kfree(opts);
911 }
912 
913 static struct usb_function_instance *f_audio_alloc_inst(void)
914 {
915 	struct f_uac1_opts *opts;
916 
917 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
918 	if (!opts)
919 		return ERR_PTR(-ENOMEM);
920 
921 	mutex_init(&opts->lock);
922 	opts->func_inst.free_func_inst = f_audio_free_inst;
923 
924 	config_group_init_type_name(&opts->func_inst.group, "",
925 				    &f_uac1_func_type);
926 
927 	opts->req_buf_size = UAC1_OUT_EP_MAX_PACKET_SIZE;
928 	opts->req_count = UAC1_REQ_COUNT;
929 	opts->audio_buf_size = UAC1_AUDIO_BUF_SIZE;
930 	opts->fn_play = FILE_PCM_PLAYBACK;
931 	opts->fn_cap = FILE_PCM_CAPTURE;
932 	opts->fn_cntl = FILE_CONTROL;
933 	return &opts->func_inst;
934 }
935 
936 static void f_audio_free(struct usb_function *f)
937 {
938 	struct f_audio *audio = func_to_audio(f);
939 	struct f_uac1_opts *opts;
940 
941 	gaudio_cleanup(&audio->card);
942 	opts = container_of(f->fi, struct f_uac1_opts, func_inst);
943 	kfree(audio);
944 	mutex_lock(&opts->lock);
945 	--opts->refcnt;
946 	mutex_unlock(&opts->lock);
947 }
948 
949 static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
950 {
951 	usb_free_all_descriptors(f);
952 }
953 
954 static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
955 {
956 	struct f_audio *audio;
957 	struct f_uac1_opts *opts;
958 
959 	/* allocate and initialize one new instance */
960 	audio = kzalloc(sizeof(*audio), GFP_KERNEL);
961 	if (!audio)
962 		return ERR_PTR(-ENOMEM);
963 
964 	audio->card.func.name = "g_audio";
965 
966 	opts = container_of(fi, struct f_uac1_opts, func_inst);
967 	mutex_lock(&opts->lock);
968 	++opts->refcnt;
969 	mutex_unlock(&opts->lock);
970 	INIT_LIST_HEAD(&audio->play_queue);
971 	spin_lock_init(&audio->lock);
972 
973 	audio->card.func.bind = f_audio_bind;
974 	audio->card.func.unbind = f_audio_unbind;
975 	audio->card.func.set_alt = f_audio_set_alt;
976 	audio->card.func.setup = f_audio_setup;
977 	audio->card.func.disable = f_audio_disable;
978 	audio->card.func.free_func = f_audio_free;
979 
980 	control_selector_init(audio);
981 
982 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
983 
984 	return &audio->card.func;
985 }
986 
987 DECLARE_USB_FUNCTION_INIT(uac1, f_audio_alloc_inst, f_audio_alloc);
988 MODULE_LICENSE("GPL");
989 MODULE_AUTHOR("Bryan Wu");
990