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 
9 #include <linux/slab.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/atomic.h>
14 
15 #include "u_uac1_legacy.h"
16 
17 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value);
18 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd);
19 
20 /*
21  * DESCRIPTORS ... most are static, but strings and full
22  * configuration descriptors are built on demand.
23  */
24 
25 /*
26  * We have two interfaces- AudioControl and AudioStreaming
27  * TODO: only supcard playback currently
28  */
29 #define F_AUDIO_AC_INTERFACE	0
30 #define F_AUDIO_AS_INTERFACE	1
31 #define F_AUDIO_NUM_INTERFACES	1
32 
33 /* B.3.1  Standard AC Interface Descriptor */
34 static struct usb_interface_descriptor ac_interface_desc = {
35 	.bLength =		USB_DT_INTERFACE_SIZE,
36 	.bDescriptorType =	USB_DT_INTERFACE,
37 	.bNumEndpoints =	0,
38 	.bInterfaceClass =	USB_CLASS_AUDIO,
39 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
40 };
41 
42 /*
43  * The number of AudioStreaming and MIDIStreaming interfaces
44  * in the Audio Interface Collection
45  */
46 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
47 
48 #define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
49 /* 1 input terminal, 1 output terminal and 1 feature unit */
50 #define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH + UAC_DT_INPUT_TERMINAL_SIZE \
51 	+ UAC_DT_OUTPUT_TERMINAL_SIZE + UAC_DT_FEATURE_UNIT_SIZE(0))
52 /* B.3.2  Class-Specific AC Interface Descriptor */
53 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
54 	.bLength =		UAC_DT_AC_HEADER_LENGTH,
55 	.bDescriptorType =	USB_DT_CS_INTERFACE,
56 	.bDescriptorSubtype =	UAC_HEADER,
57 	.bcdADC =		cpu_to_le16(0x0100),
58 	.wTotalLength =		cpu_to_le16(UAC_DT_TOTAL_LENGTH),
59 	.bInCollection =	F_AUDIO_NUM_INTERFACES,
60 	.baInterfaceNr = {
61 	/* Interface number of the first AudioStream interface */
62 		[0] =		1,
63 	}
64 };
65 
66 #define INPUT_TERMINAL_ID	1
67 static struct uac_input_terminal_descriptor input_terminal_desc = {
68 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
69 	.bDescriptorType =	USB_DT_CS_INTERFACE,
70 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
71 	.bTerminalID =		INPUT_TERMINAL_ID,
72 	.wTerminalType =	UAC_TERMINAL_STREAMING,
73 	.bAssocTerminal =	0,
74 	.wChannelConfig =	0x3,
75 };
76 
77 DECLARE_UAC_FEATURE_UNIT_DESCRIPTOR(0);
78 
79 #define FEATURE_UNIT_ID		2
80 static struct uac_feature_unit_descriptor_0 feature_unit_desc = {
81 	.bLength		= UAC_DT_FEATURE_UNIT_SIZE(0),
82 	.bDescriptorType	= USB_DT_CS_INTERFACE,
83 	.bDescriptorSubtype	= UAC_FEATURE_UNIT,
84 	.bUnitID		= FEATURE_UNIT_ID,
85 	.bSourceID		= INPUT_TERMINAL_ID,
86 	.bControlSize		= 2,
87 	.bmaControls[0]		= (UAC_FU_MUTE | UAC_FU_VOLUME),
88 };
89 
90 static struct usb_audio_control mute_control = {
91 	.list = LIST_HEAD_INIT(mute_control.list),
92 	.name = "Mute Control",
93 	.type = UAC_FU_MUTE,
94 	/* Todo: add real Mute control code */
95 	.set = generic_set_cmd,
96 	.get = generic_get_cmd,
97 };
98 
99 static struct usb_audio_control volume_control = {
100 	.list = LIST_HEAD_INIT(volume_control.list),
101 	.name = "Volume Control",
102 	.type = UAC_FU_VOLUME,
103 	/* Todo: add real Volume control code */
104 	.set = generic_set_cmd,
105 	.get = generic_get_cmd,
106 };
107 
108 static struct usb_audio_control_selector feature_unit = {
109 	.list = LIST_HEAD_INIT(feature_unit.list),
110 	.id = FEATURE_UNIT_ID,
111 	.name = "Mute & Volume Control",
112 	.type = UAC_FEATURE_UNIT,
113 	.desc = (struct usb_descriptor_header *)&feature_unit_desc,
114 };
115 
116 #define OUTPUT_TERMINAL_ID	3
117 static struct uac1_output_terminal_descriptor output_terminal_desc = {
118 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
119 	.bDescriptorType	= USB_DT_CS_INTERFACE,
120 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
121 	.bTerminalID		= OUTPUT_TERMINAL_ID,
122 	.wTerminalType		= UAC_OUTPUT_TERMINAL_SPEAKER,
123 	.bAssocTerminal		= FEATURE_UNIT_ID,
124 	.bSourceID		= FEATURE_UNIT_ID,
125 };
126 
127 /* B.4.1  Standard AS Interface Descriptor */
128 static struct usb_interface_descriptor as_interface_alt_0_desc = {
129 	.bLength =		USB_DT_INTERFACE_SIZE,
130 	.bDescriptorType =	USB_DT_INTERFACE,
131 	.bAlternateSetting =	0,
132 	.bNumEndpoints =	0,
133 	.bInterfaceClass =	USB_CLASS_AUDIO,
134 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
135 };
136 
137 static struct usb_interface_descriptor as_interface_alt_1_desc = {
138 	.bLength =		USB_DT_INTERFACE_SIZE,
139 	.bDescriptorType =	USB_DT_INTERFACE,
140 	.bAlternateSetting =	1,
141 	.bNumEndpoints =	1,
142 	.bInterfaceClass =	USB_CLASS_AUDIO,
143 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOSTREAMING,
144 };
145 
146 /* B.4.2  Class-Specific AS Interface Descriptor */
147 static struct uac1_as_header_descriptor as_header_desc = {
148 	.bLength =		UAC_DT_AS_HEADER_SIZE,
149 	.bDescriptorType =	USB_DT_CS_INTERFACE,
150 	.bDescriptorSubtype =	UAC_AS_GENERAL,
151 	.bTerminalLink =	INPUT_TERMINAL_ID,
152 	.bDelay =		1,
153 	.wFormatTag =		UAC_FORMAT_TYPE_I_PCM,
154 };
155 
156 DECLARE_UAC_FORMAT_TYPE_I_DISCRETE_DESC(1);
157 
158 static struct uac_format_type_i_discrete_descriptor_1 as_type_i_desc = {
159 	.bLength =		UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(1),
160 	.bDescriptorType =	USB_DT_CS_INTERFACE,
161 	.bDescriptorSubtype =	UAC_FORMAT_TYPE,
162 	.bFormatType =		UAC_FORMAT_TYPE_I,
163 	.bSubframeSize =	2,
164 	.bBitResolution =	16,
165 	.bSamFreqType =		1,
166 };
167 
168 /* Standard ISO OUT Endpoint Descriptor */
169 static struct usb_endpoint_descriptor as_out_ep_desc  = {
170 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
171 	.bDescriptorType =	USB_DT_ENDPOINT,
172 	.bEndpointAddress =	USB_DIR_OUT,
173 	.bmAttributes =		USB_ENDPOINT_SYNC_ADAPTIVE
174 				| USB_ENDPOINT_XFER_ISOC,
175 	.wMaxPacketSize	=	cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
176 	.bInterval =		4,
177 };
178 
179 /* Class-specific AS ISO OUT Endpoint Descriptor */
180 static struct uac_iso_endpoint_descriptor as_iso_out_desc = {
181 	.bLength =		UAC_ISO_ENDPOINT_DESC_SIZE,
182 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
183 	.bDescriptorSubtype =	UAC_EP_GENERAL,
184 	.bmAttributes = 	1,
185 	.bLockDelayUnits =	1,
186 	.wLockDelay =		cpu_to_le16(1),
187 };
188 
189 static struct usb_descriptor_header *f_audio_desc[] = {
190 	(struct usb_descriptor_header *)&ac_interface_desc,
191 	(struct usb_descriptor_header *)&ac_header_desc,
192 
193 	(struct usb_descriptor_header *)&input_terminal_desc,
194 	(struct usb_descriptor_header *)&output_terminal_desc,
195 	(struct usb_descriptor_header *)&feature_unit_desc,
196 
197 	(struct usb_descriptor_header *)&as_interface_alt_0_desc,
198 	(struct usb_descriptor_header *)&as_interface_alt_1_desc,
199 	(struct usb_descriptor_header *)&as_header_desc,
200 
201 	(struct usb_descriptor_header *)&as_type_i_desc,
202 
203 	(struct usb_descriptor_header *)&as_out_ep_desc,
204 	(struct usb_descriptor_header *)&as_iso_out_desc,
205 	NULL,
206 };
207 
208 enum {
209 	STR_AC_IF,
210 	STR_INPUT_TERMINAL,
211 	STR_INPUT_TERMINAL_CH_NAMES,
212 	STR_FEAT_DESC_0,
213 	STR_OUTPUT_TERMINAL,
214 	STR_AS_IF_ALT0,
215 	STR_AS_IF_ALT1,
216 };
217 
218 static struct usb_string strings_uac1[] = {
219 	[STR_AC_IF].s = "AC Interface",
220 	[STR_INPUT_TERMINAL].s = "Input terminal",
221 	[STR_INPUT_TERMINAL_CH_NAMES].s = "Channels",
222 	[STR_FEAT_DESC_0].s = "Volume control & mute",
223 	[STR_OUTPUT_TERMINAL].s = "Output terminal",
224 	[STR_AS_IF_ALT0].s = "AS Interface",
225 	[STR_AS_IF_ALT1].s = "AS Interface",
226 	{ },
227 };
228 
229 static struct usb_gadget_strings str_uac1 = {
230 	.language = 0x0409,	/* en-us */
231 	.strings = strings_uac1,
232 };
233 
234 static struct usb_gadget_strings *uac1_strings[] = {
235 	&str_uac1,
236 	NULL,
237 };
238 
239 /*
240  * This function is an ALSA sound card following USB Audio Class Spec 1.0.
241  */
242 
243 /*-------------------------------------------------------------------------*/
244 struct f_audio_buf {
245 	u8 *buf;
246 	int actual;
247 	struct list_head list;
248 };
249 
250 static struct f_audio_buf *f_audio_buffer_alloc(int buf_size)
251 {
252 	struct f_audio_buf *copy_buf;
253 
254 	copy_buf = kzalloc(sizeof *copy_buf, GFP_ATOMIC);
255 	if (!copy_buf)
256 		return ERR_PTR(-ENOMEM);
257 
258 	copy_buf->buf = kzalloc(buf_size, GFP_ATOMIC);
259 	if (!copy_buf->buf) {
260 		kfree(copy_buf);
261 		return ERR_PTR(-ENOMEM);
262 	}
263 
264 	return copy_buf;
265 }
266 
267 static void f_audio_buffer_free(struct f_audio_buf *audio_buf)
268 {
269 	kfree(audio_buf->buf);
270 	kfree(audio_buf);
271 }
272 /*-------------------------------------------------------------------------*/
273 
274 struct f_audio {
275 	struct gaudio			card;
276 
277 	u8 ac_intf, ac_alt;
278 	u8 as_intf, as_alt;
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_legacy_opts *opts;
327 	int audio_buf_size;
328 	int err;
329 
330 	opts = container_of(audio->card.func.fi, struct f_uac1_legacy_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 		spin_lock_irq(&audio->lock);
340 		list_add_tail(&copy_buf->list, &audio->play_queue);
341 		spin_unlock_irq(&audio->lock);
342 		schedule_work(&audio->playback_work);
343 		copy_buf = f_audio_buffer_alloc(audio_buf_size);
344 		if (IS_ERR(copy_buf))
345 			return -ENOMEM;
346 	}
347 
348 	memcpy(copy_buf->buf + copy_buf->actual, req->buf, req->actual);
349 	copy_buf->actual += req->actual;
350 	audio->copy_buf = copy_buf;
351 
352 	err = usb_ep_queue(ep, req, GFP_ATOMIC);
353 	if (err)
354 		ERROR(cdev, "%s queue req: %d\n", ep->name, err);
355 
356 	return 0;
357 
358 }
359 
360 static void f_audio_complete(struct usb_ep *ep, struct usb_request *req)
361 {
362 	struct f_audio *audio = req->context;
363 	int status = req->status;
364 	u32 data = 0;
365 	struct usb_ep *out_ep = audio->out_ep;
366 
367 	switch (status) {
368 
369 	case 0:				/* normal completion? */
370 		if (ep == out_ep)
371 			f_audio_out_ep_complete(ep, req);
372 		else if (audio->set_con) {
373 			memcpy(&data, req->buf, req->length);
374 			audio->set_con->set(audio->set_con, audio->set_cmd,
375 					le16_to_cpu(data));
376 			audio->set_con = NULL;
377 		}
378 		break;
379 	default:
380 		break;
381 	}
382 }
383 
384 static int audio_set_intf_req(struct usb_function *f,
385 		const struct usb_ctrlrequest *ctrl)
386 {
387 	struct f_audio		*audio = func_to_audio(f);
388 	struct usb_composite_dev *cdev = f->config->cdev;
389 	struct usb_request	*req = cdev->req;
390 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
391 	u16			len = le16_to_cpu(ctrl->wLength);
392 	u16			w_value = le16_to_cpu(ctrl->wValue);
393 	u8			con_sel = (w_value >> 8) & 0xFF;
394 	u8			cmd = (ctrl->bRequest & 0x0F);
395 	struct usb_audio_control_selector *cs;
396 	struct usb_audio_control *con;
397 
398 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
399 			ctrl->bRequest, w_value, len, id);
400 
401 	list_for_each_entry(cs, &audio->cs, list) {
402 		if (cs->id == id) {
403 			list_for_each_entry(con, &cs->control, list) {
404 				if (con->type == con_sel) {
405 					audio->set_con = con;
406 					break;
407 				}
408 			}
409 			break;
410 		}
411 	}
412 
413 	audio->set_cmd = cmd;
414 	req->context = audio;
415 	req->complete = f_audio_complete;
416 
417 	return len;
418 }
419 
420 static int audio_get_intf_req(struct usb_function *f,
421 		const struct usb_ctrlrequest *ctrl)
422 {
423 	struct f_audio		*audio = func_to_audio(f);
424 	struct usb_composite_dev *cdev = f->config->cdev;
425 	struct usb_request	*req = cdev->req;
426 	int			value = -EOPNOTSUPP;
427 	u8			id = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
428 	u16			len = le16_to_cpu(ctrl->wLength);
429 	u16			w_value = le16_to_cpu(ctrl->wValue);
430 	u8			con_sel = (w_value >> 8) & 0xFF;
431 	u8			cmd = (ctrl->bRequest & 0x0F);
432 	struct usb_audio_control_selector *cs;
433 	struct usb_audio_control *con;
434 
435 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, entity %d\n",
436 			ctrl->bRequest, w_value, len, id);
437 
438 	list_for_each_entry(cs, &audio->cs, list) {
439 		if (cs->id == id) {
440 			list_for_each_entry(con, &cs->control, list) {
441 				if (con->type == con_sel && con->get) {
442 					value = con->get(con, cmd);
443 					break;
444 				}
445 			}
446 			break;
447 		}
448 	}
449 
450 	req->context = audio;
451 	req->complete = f_audio_complete;
452 	len = min_t(size_t, sizeof(value), len);
453 	memcpy(req->buf, &value, len);
454 
455 	return len;
456 }
457 
458 static int audio_set_endpoint_req(struct usb_function *f,
459 		const struct usb_ctrlrequest *ctrl)
460 {
461 	struct usb_composite_dev *cdev = f->config->cdev;
462 	int			value = -EOPNOTSUPP;
463 	u16			ep = le16_to_cpu(ctrl->wIndex);
464 	u16			len = le16_to_cpu(ctrl->wLength);
465 	u16			w_value = le16_to_cpu(ctrl->wValue);
466 
467 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
468 			ctrl->bRequest, w_value, len, ep);
469 
470 	switch (ctrl->bRequest) {
471 	case UAC_SET_CUR:
472 		value = len;
473 		break;
474 
475 	case UAC_SET_MIN:
476 		break;
477 
478 	case UAC_SET_MAX:
479 		break;
480 
481 	case UAC_SET_RES:
482 		break;
483 
484 	case UAC_SET_MEM:
485 		break;
486 
487 	default:
488 		break;
489 	}
490 
491 	return value;
492 }
493 
494 static int audio_get_endpoint_req(struct usb_function *f,
495 		const struct usb_ctrlrequest *ctrl)
496 {
497 	struct usb_composite_dev *cdev = f->config->cdev;
498 	int value = -EOPNOTSUPP;
499 	u8 ep = ((le16_to_cpu(ctrl->wIndex) >> 8) & 0xFF);
500 	u16 len = le16_to_cpu(ctrl->wLength);
501 	u16 w_value = le16_to_cpu(ctrl->wValue);
502 
503 	DBG(cdev, "bRequest 0x%x, w_value 0x%04x, len %d, endpoint %d\n",
504 			ctrl->bRequest, w_value, len, ep);
505 
506 	switch (ctrl->bRequest) {
507 	case UAC_GET_CUR:
508 	case UAC_GET_MIN:
509 	case UAC_GET_MAX:
510 	case UAC_GET_RES:
511 		value = len;
512 		break;
513 	case UAC_GET_MEM:
514 		break;
515 	default:
516 		break;
517 	}
518 
519 	return value;
520 }
521 
522 static int
523 f_audio_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
524 {
525 	struct usb_composite_dev *cdev = f->config->cdev;
526 	struct usb_request	*req = cdev->req;
527 	int			value = -EOPNOTSUPP;
528 	u16			w_index = le16_to_cpu(ctrl->wIndex);
529 	u16			w_value = le16_to_cpu(ctrl->wValue);
530 	u16			w_length = le16_to_cpu(ctrl->wLength);
531 
532 	/* composite driver infrastructure handles everything; interface
533 	 * activation uses set_alt().
534 	 */
535 	switch (ctrl->bRequestType) {
536 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
537 		value = audio_set_intf_req(f, ctrl);
538 		break;
539 
540 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE:
541 		value = audio_get_intf_req(f, ctrl);
542 		break;
543 
544 	case USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
545 		value = audio_set_endpoint_req(f, ctrl);
546 		break;
547 
548 	case USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT:
549 		value = audio_get_endpoint_req(f, ctrl);
550 		break;
551 
552 	default:
553 		ERROR(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
554 			ctrl->bRequestType, ctrl->bRequest,
555 			w_value, w_index, w_length);
556 	}
557 
558 	/* respond with data transfer or status phase? */
559 	if (value >= 0) {
560 		DBG(cdev, "audio req%02x.%02x v%04x i%04x l%d\n",
561 			ctrl->bRequestType, ctrl->bRequest,
562 			w_value, w_index, w_length);
563 		req->zero = 0;
564 		req->length = value;
565 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
566 		if (value < 0)
567 			ERROR(cdev, "audio response on err %d\n", value);
568 	}
569 
570 	/* device either stalls (value < 0) or reports success */
571 	return value;
572 }
573 
574 static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
575 {
576 	struct f_audio		*audio = func_to_audio(f);
577 	struct usb_composite_dev *cdev = f->config->cdev;
578 	struct usb_ep *out_ep = audio->out_ep;
579 	struct usb_request *req;
580 	struct f_uac1_legacy_opts *opts;
581 	int req_buf_size, req_count, audio_buf_size;
582 	int i = 0, err = 0;
583 
584 	DBG(cdev, "intf %d, alt %d\n", intf, alt);
585 
586 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
587 	req_buf_size = opts->req_buf_size;
588 	req_count = opts->req_count;
589 	audio_buf_size = opts->audio_buf_size;
590 
591 	/* No i/f has more than 2 alt settings */
592 	if (alt > 1) {
593 		ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
594 		return -EINVAL;
595 	}
596 
597 	if (intf == audio->ac_intf) {
598 		/* Control I/f has only 1 AltSetting - 0 */
599 		if (alt) {
600 			ERROR(cdev, "%s:%d Error!\n", __func__, __LINE__);
601 			return -EINVAL;
602 		}
603 		return 0;
604 	} else if (intf == audio->as_intf) {
605 		if (alt == 1) {
606 			err = config_ep_by_speed(cdev->gadget, f, out_ep);
607 			if (err)
608 				return err;
609 
610 			usb_ep_enable(out_ep);
611 			audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);
612 			if (IS_ERR(audio->copy_buf))
613 				return -ENOMEM;
614 
615 			/*
616 			 * allocate a bunch of read buffers
617 			 * and queue them all at once.
618 			 */
619 			for (i = 0; i < req_count && err == 0; i++) {
620 				req = usb_ep_alloc_request(out_ep, GFP_ATOMIC);
621 				if (req) {
622 					req->buf = kzalloc(req_buf_size,
623 							GFP_ATOMIC);
624 					if (req->buf) {
625 						req->length = req_buf_size;
626 						req->context = audio;
627 						req->complete =
628 							f_audio_complete;
629 						err = usb_ep_queue(out_ep,
630 							req, GFP_ATOMIC);
631 						if (err)
632 							ERROR(cdev,
633 							"%s queue req: %d\n",
634 							out_ep->name, err);
635 					} else
636 						err = -ENOMEM;
637 				} else
638 					err = -ENOMEM;
639 			}
640 
641 		} else {
642 			struct f_audio_buf *copy_buf = audio->copy_buf;
643 			if (copy_buf) {
644 				list_add_tail(&copy_buf->list,
645 						&audio->play_queue);
646 				schedule_work(&audio->playback_work);
647 			}
648 		}
649 		audio->as_alt = alt;
650 	}
651 
652 	return err;
653 }
654 
655 static int f_audio_get_alt(struct usb_function *f, unsigned intf)
656 {
657 	struct f_audio		*audio = func_to_audio(f);
658 	struct usb_composite_dev *cdev = f->config->cdev;
659 
660 	if (intf == audio->ac_intf)
661 		return audio->ac_alt;
662 	else if (intf == audio->as_intf)
663 		return audio->as_alt;
664 	else
665 		ERROR(cdev, "%s:%d Invalid Interface %d!\n",
666 		      __func__, __LINE__, intf);
667 
668 	return -EINVAL;
669 }
670 
671 static void f_audio_disable(struct usb_function *f)
672 {
673 	return;
674 }
675 
676 /*-------------------------------------------------------------------------*/
677 
678 static void f_audio_build_desc(struct f_audio *audio)
679 {
680 	struct gaudio *card = &audio->card;
681 	u8 *sam_freq;
682 	int rate;
683 
684 	/* Set channel numbers */
685 	input_terminal_desc.bNrChannels = u_audio_get_playback_channels(card);
686 	as_type_i_desc.bNrChannels = u_audio_get_playback_channels(card);
687 
688 	/* Set sample rates */
689 	rate = u_audio_get_playback_rate(card);
690 	sam_freq = as_type_i_desc.tSamFreq[0];
691 	memcpy(sam_freq, &rate, 3);
692 
693 	/* Todo: Set Sample bits and other parameters */
694 
695 	return;
696 }
697 
698 /* audio function driver setup/binding */
699 static int
700 f_audio_bind(struct usb_configuration *c, struct usb_function *f)
701 {
702 	struct usb_composite_dev *cdev = c->cdev;
703 	struct f_audio		*audio = func_to_audio(f);
704 	struct usb_string	*us;
705 	int			status;
706 	struct usb_ep		*ep = NULL;
707 	struct f_uac1_legacy_opts	*audio_opts;
708 
709 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
710 	audio->card.gadget = c->cdev->gadget;
711 	/* set up ASLA audio devices */
712 	if (!audio_opts->bound) {
713 		status = gaudio_setup(&audio->card);
714 		if (status < 0)
715 			return status;
716 		audio_opts->bound = true;
717 	}
718 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
719 	if (IS_ERR(us))
720 		return PTR_ERR(us);
721 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
722 	input_terminal_desc.iTerminal = us[STR_INPUT_TERMINAL].id;
723 	input_terminal_desc.iChannelNames = us[STR_INPUT_TERMINAL_CH_NAMES].id;
724 	feature_unit_desc.iFeature = us[STR_FEAT_DESC_0].id;
725 	output_terminal_desc.iTerminal = us[STR_OUTPUT_TERMINAL].id;
726 	as_interface_alt_0_desc.iInterface = us[STR_AS_IF_ALT0].id;
727 	as_interface_alt_1_desc.iInterface = us[STR_AS_IF_ALT1].id;
728 
729 
730 	f_audio_build_desc(audio);
731 
732 	/* allocate instance-specific interface IDs, and patch descriptors */
733 	status = usb_interface_id(c, f);
734 	if (status < 0)
735 		goto fail;
736 	ac_interface_desc.bInterfaceNumber = status;
737 	audio->ac_intf = status;
738 	audio->ac_alt = 0;
739 
740 	status = usb_interface_id(c, f);
741 	if (status < 0)
742 		goto fail;
743 	as_interface_alt_0_desc.bInterfaceNumber = status;
744 	as_interface_alt_1_desc.bInterfaceNumber = status;
745 	audio->as_intf = status;
746 	audio->as_alt = 0;
747 
748 	status = -ENODEV;
749 
750 	/* allocate instance-specific endpoints */
751 	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
752 	if (!ep)
753 		goto fail;
754 	audio->out_ep = ep;
755 	audio->out_ep->desc = &as_out_ep_desc;
756 
757 	/* copy descriptors, and track endpoint copies */
758 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
759 					NULL);
760 	if (status)
761 		goto fail;
762 	return 0;
763 
764 fail:
765 	gaudio_cleanup(&audio->card);
766 	return status;
767 }
768 
769 /*-------------------------------------------------------------------------*/
770 
771 static int generic_set_cmd(struct usb_audio_control *con, u8 cmd, int value)
772 {
773 	con->data[cmd] = value;
774 
775 	return 0;
776 }
777 
778 static int generic_get_cmd(struct usb_audio_control *con, u8 cmd)
779 {
780 	return con->data[cmd];
781 }
782 
783 /* Todo: add more control selecotor dynamically */
784 static int control_selector_init(struct f_audio *audio)
785 {
786 	INIT_LIST_HEAD(&audio->cs);
787 	list_add(&feature_unit.list, &audio->cs);
788 
789 	INIT_LIST_HEAD(&feature_unit.control);
790 	list_add(&mute_control.list, &feature_unit.control);
791 	list_add(&volume_control.list, &feature_unit.control);
792 
793 	volume_control.data[UAC__CUR] = 0xffc0;
794 	volume_control.data[UAC__MIN] = 0xe3a0;
795 	volume_control.data[UAC__MAX] = 0xfff0;
796 	volume_control.data[UAC__RES] = 0x0030;
797 
798 	return 0;
799 }
800 
801 static inline
802 struct f_uac1_legacy_opts *to_f_uac1_opts(struct config_item *item)
803 {
804 	return container_of(to_config_group(item), struct f_uac1_legacy_opts,
805 			    func_inst.group);
806 }
807 
808 static void f_uac1_attr_release(struct config_item *item)
809 {
810 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);
811 
812 	usb_put_function_instance(&opts->func_inst);
813 }
814 
815 static struct configfs_item_operations f_uac1_item_ops = {
816 	.release	= f_uac1_attr_release,
817 };
818 
819 #define UAC1_INT_ATTRIBUTE(name)					\
820 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
821 					 char *page)			\
822 {									\
823 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
824 	int result;							\
825 									\
826 	mutex_lock(&opts->lock);					\
827 	result = sprintf(page, "%u\n", opts->name);			\
828 	mutex_unlock(&opts->lock);					\
829 									\
830 	return result;							\
831 }									\
832 									\
833 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,		\
834 					  const char *page, size_t len)	\
835 {									\
836 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
837 	int ret;							\
838 	u32 num;							\
839 									\
840 	mutex_lock(&opts->lock);					\
841 	if (opts->refcnt) {						\
842 		ret = -EBUSY;						\
843 		goto end;						\
844 	}								\
845 									\
846 	ret = kstrtou32(page, 0, &num);					\
847 	if (ret)							\
848 		goto end;						\
849 									\
850 	opts->name = num;						\
851 	ret = len;							\
852 									\
853 end:									\
854 	mutex_unlock(&opts->lock);					\
855 	return ret;							\
856 }									\
857 									\
858 CONFIGFS_ATTR(f_uac1_opts_, name)
859 
860 UAC1_INT_ATTRIBUTE(req_buf_size);
861 UAC1_INT_ATTRIBUTE(req_count);
862 UAC1_INT_ATTRIBUTE(audio_buf_size);
863 
864 #define UAC1_STR_ATTRIBUTE(name)					\
865 static ssize_t f_uac1_opts_##name##_show(struct config_item *item,	\
866 					 char *page)			\
867 {									\
868 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
869 	int result;							\
870 									\
871 	mutex_lock(&opts->lock);					\
872 	result = sprintf(page, "%s\n", opts->name);			\
873 	mutex_unlock(&opts->lock);					\
874 									\
875 	return result;							\
876 }									\
877 									\
878 static ssize_t f_uac1_opts_##name##_store(struct config_item *item,	\
879 					  const char *page, size_t len)	\
880 {									\
881 	struct f_uac1_legacy_opts *opts = to_f_uac1_opts(item);		\
882 	int ret = -EBUSY;						\
883 	char *tmp;							\
884 									\
885 	mutex_lock(&opts->lock);					\
886 	if (opts->refcnt)						\
887 		goto end;						\
888 									\
889 	tmp = kstrndup(page, len, GFP_KERNEL);				\
890 	if (tmp) {							\
891 		ret = -ENOMEM;						\
892 		goto end;						\
893 	}								\
894 	if (opts->name##_alloc)						\
895 		kfree(opts->name);					\
896 	opts->name##_alloc = true;					\
897 	opts->name = tmp;						\
898 	ret = len;							\
899 									\
900 end:									\
901 	mutex_unlock(&opts->lock);					\
902 	return ret;							\
903 }									\
904 									\
905 CONFIGFS_ATTR(f_uac1_opts_, name)
906 
907 UAC1_STR_ATTRIBUTE(fn_play);
908 UAC1_STR_ATTRIBUTE(fn_cap);
909 UAC1_STR_ATTRIBUTE(fn_cntl);
910 
911 static struct configfs_attribute *f_uac1_attrs[] = {
912 	&f_uac1_opts_attr_req_buf_size,
913 	&f_uac1_opts_attr_req_count,
914 	&f_uac1_opts_attr_audio_buf_size,
915 	&f_uac1_opts_attr_fn_play,
916 	&f_uac1_opts_attr_fn_cap,
917 	&f_uac1_opts_attr_fn_cntl,
918 	NULL,
919 };
920 
921 static const struct config_item_type f_uac1_func_type = {
922 	.ct_item_ops	= &f_uac1_item_ops,
923 	.ct_attrs	= f_uac1_attrs,
924 	.ct_owner	= THIS_MODULE,
925 };
926 
927 static void f_audio_free_inst(struct usb_function_instance *f)
928 {
929 	struct f_uac1_legacy_opts *opts;
930 
931 	opts = container_of(f, struct f_uac1_legacy_opts, func_inst);
932 	if (opts->fn_play_alloc)
933 		kfree(opts->fn_play);
934 	if (opts->fn_cap_alloc)
935 		kfree(opts->fn_cap);
936 	if (opts->fn_cntl_alloc)
937 		kfree(opts->fn_cntl);
938 	kfree(opts);
939 }
940 
941 static struct usb_function_instance *f_audio_alloc_inst(void)
942 {
943 	struct f_uac1_legacy_opts *opts;
944 
945 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
946 	if (!opts)
947 		return ERR_PTR(-ENOMEM);
948 
949 	mutex_init(&opts->lock);
950 	opts->func_inst.free_func_inst = f_audio_free_inst;
951 
952 	config_group_init_type_name(&opts->func_inst.group, "",
953 				    &f_uac1_func_type);
954 
955 	opts->req_buf_size = UAC1_OUT_EP_MAX_PACKET_SIZE;
956 	opts->req_count = UAC1_REQ_COUNT;
957 	opts->audio_buf_size = UAC1_AUDIO_BUF_SIZE;
958 	opts->fn_play = FILE_PCM_PLAYBACK;
959 	opts->fn_cap = FILE_PCM_CAPTURE;
960 	opts->fn_cntl = FILE_CONTROL;
961 	return &opts->func_inst;
962 }
963 
964 static void f_audio_free(struct usb_function *f)
965 {
966 	struct f_audio *audio = func_to_audio(f);
967 	struct f_uac1_legacy_opts *opts;
968 
969 	gaudio_cleanup(&audio->card);
970 	opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
971 	kfree(audio);
972 	mutex_lock(&opts->lock);
973 	--opts->refcnt;
974 	mutex_unlock(&opts->lock);
975 }
976 
977 static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
978 {
979 	usb_free_all_descriptors(f);
980 }
981 
982 static struct usb_function *f_audio_alloc(struct usb_function_instance *fi)
983 {
984 	struct f_audio *audio;
985 	struct f_uac1_legacy_opts *opts;
986 
987 	/* allocate and initialize one new instance */
988 	audio = kzalloc(sizeof(*audio), GFP_KERNEL);
989 	if (!audio)
990 		return ERR_PTR(-ENOMEM);
991 
992 	audio->card.func.name = "g_audio";
993 
994 	opts = container_of(fi, struct f_uac1_legacy_opts, func_inst);
995 	mutex_lock(&opts->lock);
996 	++opts->refcnt;
997 	mutex_unlock(&opts->lock);
998 	INIT_LIST_HEAD(&audio->play_queue);
999 	spin_lock_init(&audio->lock);
1000 
1001 	audio->card.func.bind = f_audio_bind;
1002 	audio->card.func.unbind = f_audio_unbind;
1003 	audio->card.func.set_alt = f_audio_set_alt;
1004 	audio->card.func.get_alt = f_audio_get_alt;
1005 	audio->card.func.setup = f_audio_setup;
1006 	audio->card.func.disable = f_audio_disable;
1007 	audio->card.func.free_func = f_audio_free;
1008 
1009 	control_selector_init(audio);
1010 
1011 	INIT_WORK(&audio->playback_work, f_audio_playback_work);
1012 
1013 	return &audio->card.func;
1014 }
1015 
1016 DECLARE_USB_FUNCTION_INIT(uac1_legacy, f_audio_alloc_inst, f_audio_alloc);
1017 MODULE_LICENSE("GPL");
1018 MODULE_AUTHOR("Bryan Wu");
1019