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_legacy.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 	u8 ac_intf, ac_alt;
281 	u8 as_intf, as_alt;
282 
283 	/* endpoints handle full and/or high speeds */
284 	struct usb_ep			*out_ep;
285 
286 	spinlock_t			lock;
287 	struct f_audio_buf *copy_buf;
288 	struct work_struct playback_work;
289 	struct list_head play_queue;
290 
291 	/* Control Set command */
292 	struct list_head cs;
293 	u8 set_cmd;
294 	struct usb_audio_control *set_con;
295 };
296 
297 static inline struct f_audio *func_to_audio(struct usb_function *f)
298 {
299 	return container_of(f, struct f_audio, card.func);
300 }
301 
302 /*-------------------------------------------------------------------------*/
303 
304 static void f_audio_playback_work(struct work_struct *data)
305 {
306 	struct f_audio *audio = container_of(data, struct f_audio,
307 					playback_work);
308 	struct f_audio_buf *play_buf;
309 
310 	spin_lock_irq(&audio->lock);
311 	if (list_empty(&audio->play_queue)) {
312 		spin_unlock_irq(&audio->lock);
313 		return;
314 	}
315 	play_buf = list_first_entry(&audio->play_queue,
316 			struct f_audio_buf, list);
317 	list_del(&play_buf->list);
318 	spin_unlock_irq(&audio->lock);
319 
320 	u_audio_playback(&audio->card, play_buf->buf, play_buf->actual);
321 	f_audio_buffer_free(play_buf);
322 }
323 
324 static int f_audio_out_ep_complete(struct usb_ep *ep, struct usb_request *req)
325 {
326 	struct f_audio *audio = req->context;
327 	struct usb_composite_dev *cdev = audio->card.func.config->cdev;
328 	struct f_audio_buf *copy_buf = audio->copy_buf;
329 	struct f_uac1_legacy_opts *opts;
330 	int audio_buf_size;
331 	int err;
332 
333 	opts = container_of(audio->card.func.fi, struct f_uac1_legacy_opts,
334 			    func_inst);
335 	audio_buf_size = opts->audio_buf_size;
336 
337 	if (!copy_buf)
338 		return -EINVAL;
339 
340 	/* Copy buffer is full, add it to the play_queue */
341 	if (audio_buf_size - copy_buf->actual < req->actual) {
342 		list_add_tail(&copy_buf->list, &audio->play_queue);
343 		schedule_work(&audio->playback_work);
344 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
345 		if (IS_ERR(copy_buf))
346 			return -ENOMEM;
347 	}
348 
349 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
350 	copy_buf->actual += req->actual;
351 	audio->copy_buf = copy_buf;
352 
353 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
354 	if (err)
355 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);
356 
357 	return 0;
358 
359 }
360 
361 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
362 {
363 	struct f_audio *audio = req->context;
364 	int status = req->status;
365 	u32 data = 0;
366 	struct usb_ep *out_ep = audio->out_ep;
367 
368 	switch (status) {
369 
370 	case 0:				/* normal completion? */
371 		if (ep == out_ep)
372 			f_audio_out_ep_complete(ep, req);
373 		else if (audio->set_con) {
374 			memcpy(&data, req->buf, req->length);
375 			audio->set_con->set(audio->set_con, audio->set_cmd,
376 					le16_to_cpu(data));
377 			audio->set_con = NULL;
378 		}
379 		break;
380 	default:
381 		break;
382 	}
383 }
384 
385 static int audio_set_intf_req(struct usb_function *f,
386 		const struct usb_ctrlrequest *ctrl)
387 {
388 	struct f_audio		*audio = func_to_audio(f);
389 	struct usb_composite_dev *cdev = f->config->cdev;
390 	struct usb_request	*req = cdev->req;
391 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
392 	u16			len = le16_to_cpu(ctrl->wLength);
393 	u16			w_value = le16_to_cpu(ctrl->wValue);
394 	u8			con_sel = (w_value >> 8) & 0xFF;
395 	u8			cmd = (ctrl->bRequest & 0x0F);
396 	struct usb_audio_control_selector *cs;
397 	struct usb_audio_control *con;
398 
399 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
400 			ctrl->bRequest, w_value, len, id);
401 
402 	list_for_each_entry(cs, &audio->cs, list) {
403 		if (cs->id == id) {
404 			list_for_each_entry(con, &cs->control, list) {
405 				if (con->type == con_sel) {
406 					audio->set_con = con;
407 					break;
408 				}
409 			}
410 			break;
411 		}
412 	}
413 
414 	audio->set_cmd = cmd;
415 	req->context = audio;
416 	req->complete = f_audio_complete;
417 
418 	return len;
419 }
420 
421 static int audio_get_intf_req(struct usb_function *f,
422 		const struct usb_ctrlrequest *ctrl)
423 {
424 	struct f_audio		*audio = func_to_audio(f);
425 	struct usb_composite_dev *cdev = f->config->cdev;
426 	struct usb_request	*req = cdev->req;
427 	int			value = -EOPNOTSUPP;
428 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
429 	u16			len = le16_to_cpu(ctrl->wLength);
430 	u16			w_value = le16_to_cpu(ctrl->wValue);
431 	u8			con_sel = (w_value >> 8) & 0xFF;
432 	u8			cmd = (ctrl->bRequest & 0x0F);
433 	struct usb_audio_control_selector *cs;
434 	struct usb_audio_control *con;
435 
436 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
437 			ctrl->bRequest, w_value, len, id);
438 
439 	list_for_each_entry(cs, &audio->cs, list) {
440 		if (cs->id == id) {
441 			list_for_each_entry(con, &cs->control, list) {
442 				if (con->type == con_sel && con->get) {
443 					value = con->get(con, cmd);
444 					break;
445 				}
446 			}
447 			break;
448 		}
449 	}
450 
451 	req->context = audio;
452 	req->complete = f_audio_complete;
453 	len = min_t(size_t, sizeof(value), len);
454 	memcpy(req->buf, &value, len);
455 
456 	return len;
457 }
458 
459 static int audio_set_endpoint_req(struct usb_function *f,
460 		const struct usb_ctrlrequest *ctrl)
461 {
462 	struct usb_composite_dev *cdev = f->config->cdev;
463 	int			value = -EOPNOTSUPP;
464 	u16			ep = le16_to_cpu(ctrl->wIndex);
465 	u16			len = le16_to_cpu(ctrl->wLength);
466 	u16			w_value = le16_to_cpu(ctrl->wValue);
467 
468 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
469 			ctrl->bRequest, w_value, len, ep);
470 
471 	switch (ctrl->bRequest) {
472 	case UAC_SET_CUR:
473 		value = len;
474 		break;
475 
476 	case UAC_SET_MIN:
477 		break;
478 
479 	case UAC_SET_MAX:
480 		break;
481 
482 	case UAC_SET_RES:
483 		break;
484 
485 	case UAC_SET_MEM:
486 		break;
487 
488 	default:
489 		break;
490 	}
491 
492 	return value;
493 }
494 
495 static int audio_get_endpoint_req(struct usb_function *f,
496 		const struct usb_ctrlrequest *ctrl)
497 {
498 	struct usb_composite_dev *cdev = f->config->cdev;
499 	int value = -EOPNOTSUPP;
500 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
501 	u16 len = le16_to_cpu(ctrl->wLength);
502 	u16 w_value = le16_to_cpu(ctrl->wValue);
503 
504 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
505 			ctrl->bRequest, w_value, len, ep);
506 
507 	switch (ctrl->bRequest) {
508 	case UAC_GET_CUR:
509 	case UAC_GET_MIN:
510 	case UAC_GET_MAX:
511 	case UAC_GET_RES:
512 		value = len;
513 		break;
514 	case UAC_GET_MEM:
515 		break;
516 	default:
517 		break;
518 	}
519 
520 	return value;
521 }
522 
523 static int
524 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
525 {
526 	struct usb_composite_dev *cdev = f->config->cdev;
527 	struct usb_request	*req = cdev->req;
528 	int			value = -EOPNOTSUPP;
529 	u16			w_index = le16_to_cpu(ctrl->wIndex);
530 	u16			w_value = le16_to_cpu(ctrl->wValue);
531 	u16			w_length = le16_to_cpu(ctrl->wLength);
532 
533 	/* composite driver infrastructure handles everything; interface
534 	 * activation uses set_alt().
535 	 */
536 	switch (ctrl->bRequestType) {
537 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
538 		value = audio_set_intf_req(f, ctrl);
539 		break;
540 
541 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
542 		value = audio_get_intf_req(f, ctrl);
543 		break;
544 
545 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
546 		value = audio_set_endpoint_req(f, ctrl);
547 		break;
548 
549 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
550 		value = audio_get_endpoint_req(f, ctrl);
551 		break;
552 
553 	default:
554 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
555 			ctrl->bRequestType, ctrl->bRequest,
556 			w_value, w_index, w_length);
557 	}
558 
559 	/* respond with data transfer or status phase? */
560 	if (value >= 0) {
561 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
562 			ctrl->bRequestType, ctrl->bRequest,
563 			w_value, w_index, w_length);
564 		req->zero = 0;
565 		req->length = value;
566 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
567 		if (value < 0)
568 			ERROR(cdev, "audio response on err %d\n", value);
569 	}
570 
571 	/* device either stalls (value < 0) or reports success */
572 	return value;
573 }
574 
575 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
576 {
577 	struct f_audio		*audio = func_to_audio(f);
578 	struct usb_composite_dev *cdev = f->config->cdev;
579 	struct usb_ep *out_ep = audio->out_ep;
580 	struct usb_request *req;
581 	struct f_uac1_legacy_opts *opts;
582 	int req_buf_size, req_count, audio_buf_size;
583 	int i = 0, err = 0;
584 
585 	DBG(cdev, "intf %d, alt %d\n", intf, alt);
586 
587 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
588 	req_buf_size = opts->req_buf_size;
589 	req_count = opts->req_count;
590 	audio_buf_size = opts->audio_buf_size;
591 
592 	/* No i/f has more than 2 alt settings */
593 	if (alt > 1) {
594 		ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
595 		return -EINVAL;
596 	}
597 
598 	if (intf == audio->ac_intf) {
599 		/* Control I/f has only 1 AltSetting - 0 */
600 		if (alt) {
601 			ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
602 			return -EINVAL;
603 		}
604 		return 0;
605 	} else if (intf == audio->as_intf) {
606 		if (alt == 1) {
607 			err = config_ep_by_speed(cdev->gadget, f, out_ep);
608 			if (err)
609 				return err;
610 
611 			usb_ep_enable(out_ep);
612 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
613 			if (IS_ERR(audio->copy_buf))
614 				return -ENOMEM;
615 
616 			/*
617 			 * allocate a bunch of read buffers
618 			 * and queue them all at once.
619 			 */
620 			for (i = 0; i < req_count && err == 0; i++) {
621 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
622 				if (req) {
623 					req->buf = kzalloc(req_buf_size,
624 							GFP_ATOMIC);
625 					if (req->buf) {
626 						req->length = req_buf_size;
627 						req->context = audio;
628 						req->complete =
629 							f_audio_complete;
630 						err = usb_ep_queue(out_ep,
631 							req, GFP_ATOMIC);
632 						if (err)
633 							ERROR(cdev,
634 							"%s queue req: %d\n",
635 							out_ep->name, err);
636 					} else
637 						err = -ENOMEM;
638 				} else
639 					err = -ENOMEM;
640 			}
641 
642 		} else {
643 			struct f_audio_buf *copy_buf = audio->copy_buf;
644 			if (copy_buf) {
645 				list_add_tail(&copy_buf->list,
646 						&audio->play_queue);
647 				schedule_work(&audio->playback_work);
648 			}
649 		}
650 		audio->as_alt = alt;
651 	}
652 
653 	return err;
654 }
655 
656 static int f_audio_get_alt(struct usb_function *f, unsigned intf)
657 {
658 	struct f_audio		*audio = func_to_audio(f);
659 	struct usb_composite_dev *cdev = f->config->cdev;
660 
661 	if (intf == audio->ac_intf)
662 		return audio->ac_alt;
663 	else if (intf == audio->as_intf)
664 		return audio->as_alt;
665 	else
666 		ERROR(cdev, "%s:%d Invalid Interface %d!\n",
667 		      __func__, __LINE__, intf);
668 
669 	return -EINVAL;
670 }
671 
672 static void f_audio_disable(struct usb_function *f)
673 {
674 	return;
675 }
676 
677 /*-------------------------------------------------------------------------*/
678 
679 static void f_audio_build_desc(struct f_audio *audio)
680 {
681 	struct gaudio *card = &audio->card;
682 	u8 *sam_freq;
683 	int rate;
684 
685 	/* Set channel numbers */
686 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
687 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);
688 
689 	/* Set sample rates */
690 	rate = u_audio_get_playback_rate(card);
691 	sam_freq = as_type_i_desc.tSamFreq[0];
692 	memcpy(sam_freq, &rate, 3);
693 
694 	/* Todo: Set Sample bits and other parameters */
695 
696 	return;
697 }
698 
699 /* audio function driver setup/binding */
700 static int
701 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
702 {
703 	struct usb_composite_dev *cdev = c->cdev;
704 	struct f_audio		*audio = func_to_audio(f);
705 	struct usb_string	*us;
706 	int			status;
707 	struct usb_ep		*ep = NULL;
708 	struct f_uac1_legacy_opts	*audio_opts;
709 
710 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
711 	audio->card.gadget = c->cdev->gadget;
712 	/* set up ASLA audio devices */
713 	if (!audio_opts->bound) {
714 		status = gaudio_setup(&audio->card);
715 		if (status < 0)
716 			return status;
717 		audio_opts->bound = true;
718 	}
719 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
720 	if (IS_ERR(us))
721 		return PTR_ERR(us);
722 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
723 	input_terminal_desc.iTerminal = us[STR_INPUT_TERMINAL].id;
724 	input_terminal_desc.iChannelNames = us[STR_INPUT_TERMINAL_CH_NAMES].id;
725 	feature_unit_desc.iFeature = us[STR_FEAT_DESC_0].id;
726 	output_terminal_desc.iTerminal = us[STR_OUTPUT_TERMINAL].id;
727 	as_interface_alt_0_desc.iInterface = us[STR_AS_IF_ALT0].id;
728 	as_interface_alt_1_desc.iInterface = us[STR_AS_IF_ALT1].id;
729 
730 
731 	f_audio_build_desc(audio);
732 
733 	/* allocate instance-specific interface IDs, and patch descriptors */
734 	status = usb_interface_id(c, f);
735 	if (status < 0)
736 		goto fail;
737 	ac_interface_desc.bInterfaceNumber = status;
738 	audio->ac_intf = status;
739 	audio->ac_alt = 0;
740 
741 	status = usb_interface_id(c, f);
742 	if (status < 0)
743 		goto fail;
744 	as_interface_alt_0_desc.bInterfaceNumber = status;
745 	as_interface_alt_1_desc.bInterfaceNumber = status;
746 	audio->as_intf = status;
747 	audio->as_alt = 0;
748 
749 	status = -ENODEV;
750 
751 	/* allocate instance-specific endpoints */
752 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
753 	if (!ep)
754 		goto fail;
755 	audio->out_ep = ep;
756 	audio->out_ep->desc = &as_out_ep_desc;
757 
758 	status = -ENOMEM;
759 
760 	/* copy descriptors, and track endpoint copies */
761 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
762 					NULL);
763 	if (status)
764 		goto fail;
765 	return 0;
766 
767 fail:
768 	gaudio_cleanup(&audio->card);
769 	return status;
770 }
771 
772 /*-------------------------------------------------------------------------*/
773 
774 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
775 {
776 	con->data[cmd] = value;
777 
778 	return 0;
779 }
780 
781 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
782 {
783 	return con->data[cmd];
784 }
785 
786 /* Todo: add more control selecotor dynamically */
787 static int control_selector_init(struct f_audio *audio)
788 {
789 	INIT_LIST_HEAD(&audio->cs);
790 	list_add(&feature_unit.list, &audio->cs);
791 
792 	INIT_LIST_HEAD(&feature_unit.control);
793 	list_add(&mute_control.list, &feature_unit.control);
794 	list_add(&volume_control.list, &feature_unit.control);
795 
796 	volume_control.data[UAC__CUR] = 0xffc0;
797 	volume_control.data[UAC__MIN] = 0xe3a0;
798 	volume_control.data[UAC__MAX] = 0xfff0;
799 	volume_control.data[UAC__RES] = 0x0030;
800 
801 	return 0;
802 }
803 
804 static inline
805 struct f_uac1_legacy_opts *to_f_uac1_opts(struct config_item *item)
806 {
807 	return container_of(to_config_group(item), struct f_uac1_legacy_opts,
808 			    func_inst.group);
809 }
810 
811 static void f_uac1_attr_release(struct config_item *item)
812 {
813 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);
814 
815 	usb_put_function_instance(&opts->func_inst);
816 }
817 
818 static struct configfs_item_operations f_uac1_item_ops = {
819 	.release	= f_uac1_attr_release,
820 };
821 
822 #define UAC1_INT_ATTRIBUTE(name)					\
823 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
824 					 char *page)			\
825 {									\
826 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
827 	int result;							\
828 									\
829 	mutex_lock(&opts->lock);					\
830 	result = sprintf(page, "%u\n", opts->name);			\
831 	mutex_unlock(&opts->lock);					\
832 									\
833 	return result;							\
834 }									\
835 									\
836 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,		\
837 					  const char *page, size_t len)	\
838 {									\
839 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
840 	int ret;							\
841 	u32 num;							\
842 									\
843 	mutex_lock(&opts->lock);					\
844 	if (opts->refcnt) {						\
845 		ret = -EBUSY;						\
846 		goto end;						\
847 	}								\
848 									\
849 	ret = kstrtou32(page, 0, &num);					\
850 	if (ret)							\
851 		goto end;						\
852 									\
853 	opts->name = num;						\
854 	ret = len;							\
855 									\
856 end:									\
857 	mutex_unlock(&opts->lock);					\
858 	return ret;							\
859 }									\
860 									\
861 CONFIGFS_ATTR(f_uac1_opts_, name)
862 
863 UAC1_INT_ATTRIBUTE(req_buf_size);
864 UAC1_INT_ATTRIBUTE(req_count);
865 UAC1_INT_ATTRIBUTE(audio_buf_size);
866 
867 #define UAC1_STR_ATTRIBUTE(name)					\
868 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
869 					 char *page)			\
870 {									\
871 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
872 	int result;							\
873 									\
874 	mutex_lock(&opts->lock);					\
875 	result = sprintf(page, "%s\n", opts->name);			\
876 	mutex_unlock(&opts->lock);					\
877 									\
878 	return result;							\
879 }									\
880 									\
881 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,	\
882 					  const char *page, size_t len)	\
883 {									\
884 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
885 	int ret = -EBUSY;						\
886 	char *tmp;							\
887 									\
888 	mutex_lock(&opts->lock);					\
889 	if (opts->refcnt)						\
890 		goto end;						\
891 									\
892 	tmp = kstrndup(page, len, GFP_KERNEL);				\
893 	if (tmp) {							\
894 		ret = -ENOMEM;						\
895 		goto end;						\
896 	}								\
897 	if (opts->name##_alloc)						\
898 		kfree(opts->name);					\
899 	opts->name##_alloc = true;					\
900 	opts->name = tmp;						\
901 	ret = len;							\
902 									\
903 end:									\
904 	mutex_unlock(&opts->lock);					\
905 	return ret;							\
906 }									\
907 									\
908 CONFIGFS_ATTR(f_uac1_opts_, name)
909 
910 UAC1_STR_ATTRIBUTE(fn_play);
911 UAC1_STR_ATTRIBUTE(fn_cap);
912 UAC1_STR_ATTRIBUTE(fn_cntl);
913 
914 static struct configfs_attribute *f_uac1_attrs[] = {
915 	&f_uac1_opts_attr_req_buf_size,
916 	&f_uac1_opts_attr_req_count,
917 	&f_uac1_opts_attr_audio_buf_size,
918 	&f_uac1_opts_attr_fn_play,
919 	&f_uac1_opts_attr_fn_cap,
920 	&f_uac1_opts_attr_fn_cntl,
921 	NULL,
922 };
923 
924 static struct config_item_type f_uac1_func_type = {
925 	.ct_item_ops	= &f_uac1_item_ops,
926 	.ct_attrs	= f_uac1_attrs,
927 	.ct_owner	= THIS_MODULE,
928 };
929 
930 static void f_audio_free_inst(struct usb_function_instance *f)
931 {
932 	struct f_uac1_legacy_opts *opts;
933 
934 	opts = container_of(f, struct f_uac1_legacy_opts, func_inst);
935 	if (opts->fn_play_alloc)
936 		kfree(opts->fn_play);
937 	if (opts->fn_cap_alloc)
938 		kfree(opts->fn_cap);
939 	if (opts->fn_cntl_alloc)
940 		kfree(opts->fn_cntl);
941 	kfree(opts);
942 }
943 
944 static struct usb_function_instance *f_audio_alloc_inst(void)
945 {
946 	struct f_uac1_legacy_opts *opts;
947 
948 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
949 	if (!opts)
950 		return ERR_PTR(-ENOMEM);
951 
952 	mutex_init(&opts->lock);
953 	opts->func_inst.free_func_inst = f_audio_free_inst;
954 
955 	config_group_init_type_name(&opts->func_inst.group, "",
956 				    &f_uac1_func_type);
957 
958 	opts->req_buf_size = UAC1_OUT_EP_MAX_PACKET_SIZE;
959 	opts->req_count = UAC1_REQ_COUNT;
960 	opts->audio_buf_size = UAC1_AUDIO_BUF_SIZE;
961 	opts->fn_play = FILE_PCM_PLAYBACK;
962 	opts->fn_cap = FILE_PCM_CAPTURE;
963 	opts->fn_cntl = FILE_CONTROL;
964 	return &opts->func_inst;
965 }
966 
967 static void f_audio_free(struct usb_function *f)
968 {
969 	struct f_audio *audio = func_to_audio(f);
970 	struct f_uac1_legacy_opts *opts;
971 
972 	gaudio_cleanup(&audio->card);
973 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
974 	kfree(audio);
975 	mutex_lock(&opts->lock);
976 	--opts->refcnt;
977 	mutex_unlock(&opts->lock);
978 }
979 
980 static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
981 {
982 	usb_free_all_descriptors(f);
983 }
984 
985 static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
986 {
987 	struct f_audio *audio;
988 	struct f_uac1_legacy_opts *opts;
989 
990 	/* allocate and initialize one new instance */
991 	audio = kzalloc(sizeof(*audio), GFP_KERNEL);
992 	if (!audio)
993 		return ERR_PTR(-ENOMEM);
994 
995 	audio->card.func.name = "g_audio";
996 
997 	opts = container_of(fi, struct f_uac1_legacy_opts, func_inst);
998 	mutex_lock(&opts->lock);
999 	++opts->refcnt;
1000 	mutex_unlock(&opts->lock);
1001 	INIT_LIST_HEAD(&audio->play_queue);
1002 	spin_lock_init(&audio->lock);
1003 
1004 	audio->card.func.bind = f_audio_bind;
1005 	audio->card.func.unbind = f_audio_unbind;
1006 	audio->card.func.set_alt = f_audio_set_alt;
1007 	audio->card.func.get_alt = f_audio_get_alt;
1008 	audio->card.func.setup = f_audio_setup;
1009 	audio->card.func.disable = f_audio_disable;
1010 	audio->card.func.free_func = f_audio_free;
1011 
1012 	control_selector_init(audio);
1013 
1014 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
1015 
1016 	return &audio->card.func;
1017 }
1018 
1019 DECLARE_USB_FUNCTION_INIT(uac1_legacy, f_audio_alloc_inst, f_audio_alloc);
1020 MODULE_LICENSE("GPL");
1021 MODULE_AUTHOR("Bryan Wu");
1022