1 /*
2  * f_midi.c -- USB MIDI class function driver
3  *
4  * Copyright (C) 2006 Thumtronics Pty Ltd.
5  * Developed for Thumtronics by Grey Innovation
6  * Ben Williamson <ben.williamson@greyinnovation.com>
7  *
8  * Rewritten for the composite framework
9  *   Copyright (C) 2011 Daniel Mack <zonque@gmail.com>
10  *
11  * Based on drivers/usb/gadget/f_audio.c,
12  *   Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
13  *   Copyright (C) 2008 Analog Devices, Inc
14  *
15  * and drivers/usb/gadget/midi.c,
16  *   Copyright (C) 2006 Thumtronics Pty Ltd.
17  *   Ben Williamson <ben.williamson@greyinnovation.com>
18  *
19  * Licensed under the GPL-2 or later.
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/device.h>
26 
27 #include <sound/core.h>
28 #include <sound/initval.h>
29 #include <sound/rawmidi.h>
30 
31 #include <linux/usb/ch9.h>
32 #include <linux/usb/gadget.h>
33 #include <linux/usb/audio.h>
34 #include <linux/usb/midi.h>
35 
36 #include "u_f.h"
37 #include "u_midi.h"
38 
39 MODULE_AUTHOR("Ben Williamson");
40 MODULE_LICENSE("GPL v2");
41 
42 static const char f_midi_shortname[] = "f_midi";
43 static const char f_midi_longname[] = "MIDI Gadget";
44 
45 /*
46  * We can only handle 16 cables on one single endpoint, as cable numbers are
47  * stored in 4-bit fields. And as the interface currently only holds one
48  * single endpoint, this is the maximum number of ports we can allow.
49  */
50 #define MAX_PORTS 16
51 
52 /*
53  * This is a gadget, and the IN/OUT naming is from the host's perspective.
54  * USB -> OUT endpoint -> rawmidi
55  * USB <- IN endpoint  <- rawmidi
56  */
57 struct gmidi_in_port {
58 	struct f_midi *midi;
59 	int active;
60 	uint8_t cable;
61 	uint8_t state;
62 #define STATE_UNKNOWN	0
63 #define STATE_1PARAM	1
64 #define STATE_2PARAM_1	2
65 #define STATE_2PARAM_2	3
66 #define STATE_SYSEX_0	4
67 #define STATE_SYSEX_1	5
68 #define STATE_SYSEX_2	6
69 	uint8_t data[2];
70 };
71 
72 struct f_midi {
73 	struct usb_function	func;
74 	struct usb_gadget	*gadget;
75 	struct usb_ep		*in_ep, *out_ep;
76 	struct snd_card		*card;
77 	struct snd_rawmidi	*rmidi;
78 
79 	struct snd_rawmidi_substream *in_substream[MAX_PORTS];
80 	struct snd_rawmidi_substream *out_substream[MAX_PORTS];
81 	struct gmidi_in_port	*in_port[MAX_PORTS];
82 
83 	unsigned long		out_triggered;
84 	struct tasklet_struct	tasklet;
85 	unsigned int in_ports;
86 	unsigned int out_ports;
87 	int index;
88 	char *id;
89 	unsigned int buflen, qlen;
90 };
91 
92 static inline struct f_midi *func_to_midi(struct usb_function *f)
93 {
94 	return container_of(f, struct f_midi, func);
95 }
96 
97 static void f_midi_transmit(struct f_midi *midi, struct usb_request *req);
98 
99 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
100 DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
101 DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
102 
103 /* B.3.1  Standard AC Interface Descriptor */
104 static struct usb_interface_descriptor ac_interface_desc = {
105 	.bLength =		USB_DT_INTERFACE_SIZE,
106 	.bDescriptorType =	USB_DT_INTERFACE,
107 	/* .bInterfaceNumber =	DYNAMIC */
108 	/* .bNumEndpoints =	DYNAMIC */
109 	.bInterfaceClass =	USB_CLASS_AUDIO,
110 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
111 	/* .iInterface =	DYNAMIC */
112 };
113 
114 /* B.3.2  Class-Specific AC Interface Descriptor */
115 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
116 	.bLength =		UAC_DT_AC_HEADER_SIZE(1),
117 	.bDescriptorType =	USB_DT_CS_INTERFACE,
118 	.bDescriptorSubtype =	USB_MS_HEADER,
119 	.bcdADC =		cpu_to_le16(0x0100),
120 	.wTotalLength =		cpu_to_le16(UAC_DT_AC_HEADER_SIZE(1)),
121 	.bInCollection =	1,
122 	/* .baInterfaceNr =	DYNAMIC */
123 };
124 
125 /* B.4.1  Standard MS Interface Descriptor */
126 static struct usb_interface_descriptor ms_interface_desc = {
127 	.bLength =		USB_DT_INTERFACE_SIZE,
128 	.bDescriptorType =	USB_DT_INTERFACE,
129 	/* .bInterfaceNumber =	DYNAMIC */
130 	.bNumEndpoints =	2,
131 	.bInterfaceClass =	USB_CLASS_AUDIO,
132 	.bInterfaceSubClass =	USB_SUBCLASS_MIDISTREAMING,
133 	/* .iInterface =	DYNAMIC */
134 };
135 
136 /* B.4.2  Class-Specific MS Interface Descriptor */
137 static struct usb_ms_header_descriptor ms_header_desc = {
138 	.bLength =		USB_DT_MS_HEADER_SIZE,
139 	.bDescriptorType =	USB_DT_CS_INTERFACE,
140 	.bDescriptorSubtype =	USB_MS_HEADER,
141 	.bcdMSC =		cpu_to_le16(0x0100),
142 	/* .wTotalLength =	DYNAMIC */
143 };
144 
145 /* B.5.1  Standard Bulk OUT Endpoint Descriptor */
146 static struct usb_endpoint_descriptor bulk_out_desc = {
147 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
148 	.bDescriptorType =	USB_DT_ENDPOINT,
149 	.bEndpointAddress =	USB_DIR_OUT,
150 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
151 };
152 
153 /* B.5.2  Class-specific MS Bulk OUT Endpoint Descriptor */
154 static struct usb_ms_endpoint_descriptor_16 ms_out_desc = {
155 	/* .bLength =		DYNAMIC */
156 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
157 	.bDescriptorSubtype =	USB_MS_GENERAL,
158 	/* .bNumEmbMIDIJack =	DYNAMIC */
159 	/* .baAssocJackID =	DYNAMIC */
160 };
161 
162 /* B.6.1  Standard Bulk IN Endpoint Descriptor */
163 static struct usb_endpoint_descriptor bulk_in_desc = {
164 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
165 	.bDescriptorType =	USB_DT_ENDPOINT,
166 	.bEndpointAddress =	USB_DIR_IN,
167 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
168 };
169 
170 /* B.6.2  Class-specific MS Bulk IN Endpoint Descriptor */
171 static struct usb_ms_endpoint_descriptor_16 ms_in_desc = {
172 	/* .bLength =		DYNAMIC */
173 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
174 	.bDescriptorSubtype =	USB_MS_GENERAL,
175 	/* .bNumEmbMIDIJack =	DYNAMIC */
176 	/* .baAssocJackID =	DYNAMIC */
177 };
178 
179 /* string IDs are assigned dynamically */
180 
181 #define STRING_FUNC_IDX			0
182 
183 static struct usb_string midi_string_defs[] = {
184 	[STRING_FUNC_IDX].s = "MIDI function",
185 	{  } /* end of list */
186 };
187 
188 static struct usb_gadget_strings midi_stringtab = {
189 	.language	= 0x0409,	/* en-us */
190 	.strings	= midi_string_defs,
191 };
192 
193 static struct usb_gadget_strings *midi_strings[] = {
194 	&midi_stringtab,
195 	NULL,
196 };
197 
198 static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
199 						    unsigned length)
200 {
201 	return alloc_ep_req(ep, length, length);
202 }
203 
204 static void free_ep_req(struct usb_ep *ep, struct usb_request *req)
205 {
206 	kfree(req->buf);
207 	usb_ep_free_request(ep, req);
208 }
209 
210 static const uint8_t f_midi_cin_length[] = {
211 	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
212 };
213 
214 /*
215  * Receives a chunk of MIDI data.
216  */
217 static void f_midi_read_data(struct usb_ep *ep, int cable,
218 			     uint8_t *data, int length)
219 {
220 	struct f_midi *midi = ep->driver_data;
221 	struct snd_rawmidi_substream *substream = midi->out_substream[cable];
222 
223 	if (!substream)
224 		/* Nobody is listening - throw it on the floor. */
225 		return;
226 
227 	if (!test_bit(cable, &midi->out_triggered))
228 		return;
229 
230 	snd_rawmidi_receive(substream, data, length);
231 }
232 
233 static void f_midi_handle_out_data(struct usb_ep *ep, struct usb_request *req)
234 {
235 	unsigned int i;
236 	u8 *buf = req->buf;
237 
238 	for (i = 0; i + 3 < req->actual; i += 4)
239 		if (buf[i] != 0) {
240 			int cable = buf[i] >> 4;
241 			int length = f_midi_cin_length[buf[i] & 0x0f];
242 			f_midi_read_data(ep, cable, &buf[i + 1], length);
243 		}
244 }
245 
246 static void
247 f_midi_complete(struct usb_ep *ep, struct usb_request *req)
248 {
249 	struct f_midi *midi = ep->driver_data;
250 	struct usb_composite_dev *cdev = midi->func.config->cdev;
251 	int status = req->status;
252 
253 	switch (status) {
254 	case 0:			 /* normal completion */
255 		if (ep == midi->out_ep) {
256 			/* We received stuff. req is queued again, below */
257 			f_midi_handle_out_data(ep, req);
258 		} else if (ep == midi->in_ep) {
259 			/* Our transmit completed. See if there's more to go.
260 			 * f_midi_transmit eats req, don't queue it again. */
261 			f_midi_transmit(midi, req);
262 			return;
263 		}
264 		break;
265 
266 	/* this endpoint is normally active while we're configured */
267 	case -ECONNABORTED:	/* hardware forced ep reset */
268 	case -ECONNRESET:	/* request dequeued */
269 	case -ESHUTDOWN:	/* disconnect from host */
270 		VDBG(cdev, "%s gone (%d), %d/%d\n", ep->name, status,
271 				req->actual, req->length);
272 		if (ep == midi->out_ep)
273 			f_midi_handle_out_data(ep, req);
274 
275 		free_ep_req(ep, req);
276 		return;
277 
278 	case -EOVERFLOW:	/* buffer overrun on read means that
279 				 * we didn't provide a big enough buffer.
280 				 */
281 	default:
282 		DBG(cdev, "%s complete --> %d, %d/%d\n", ep->name,
283 				status, req->actual, req->length);
284 		break;
285 	case -EREMOTEIO:	/* short read */
286 		break;
287 	}
288 
289 	status = usb_ep_queue(ep, req, GFP_ATOMIC);
290 	if (status) {
291 		ERROR(cdev, "kill %s:  resubmit %d bytes --> %d\n",
292 				ep->name, req->length, status);
293 		usb_ep_set_halt(ep);
294 		/* FIXME recover later ... somehow */
295 	}
296 }
297 
298 static int f_midi_start_ep(struct f_midi *midi,
299 			   struct usb_function *f,
300 			   struct usb_ep *ep)
301 {
302 	int err;
303 	struct usb_composite_dev *cdev = f->config->cdev;
304 
305 	if (ep->driver_data)
306 		usb_ep_disable(ep);
307 
308 	err = config_ep_by_speed(midi->gadget, f, ep);
309 	if (err) {
310 		ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
311 		return err;
312 	}
313 
314 	err = usb_ep_enable(ep);
315 	if (err) {
316 		ERROR(cdev, "can't start %s: %d\n", ep->name, err);
317 		return err;
318 	}
319 
320 	ep->driver_data = midi;
321 
322 	return 0;
323 }
324 
325 static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
326 {
327 	struct f_midi *midi = func_to_midi(f);
328 	struct usb_composite_dev *cdev = f->config->cdev;
329 	unsigned i;
330 	int err;
331 
332 	err = f_midi_start_ep(midi, f, midi->in_ep);
333 	if (err)
334 		return err;
335 
336 	err = f_midi_start_ep(midi, f, midi->out_ep);
337 	if (err)
338 		return err;
339 
340 	if (midi->out_ep->driver_data)
341 		usb_ep_disable(midi->out_ep);
342 
343 	err = config_ep_by_speed(midi->gadget, f, midi->out_ep);
344 	if (err) {
345 		ERROR(cdev, "can't configure %s: %d\n",
346 		      midi->out_ep->name, err);
347 		return err;
348 	}
349 
350 	err = usb_ep_enable(midi->out_ep);
351 	if (err) {
352 		ERROR(cdev, "can't start %s: %d\n",
353 		      midi->out_ep->name, err);
354 		return err;
355 	}
356 
357 	midi->out_ep->driver_data = midi;
358 
359 	/* allocate a bunch of read buffers and queue them all at once. */
360 	for (i = 0; i < midi->qlen && err == 0; i++) {
361 		struct usb_request *req =
362 			midi_alloc_ep_req(midi->out_ep, midi->buflen);
363 		if (req == NULL)
364 			return -ENOMEM;
365 
366 		req->complete = f_midi_complete;
367 		err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
368 		if (err) {
369 			ERROR(midi, "%s queue req: %d\n",
370 				    midi->out_ep->name, err);
371 		}
372 	}
373 
374 	return 0;
375 }
376 
377 static void f_midi_disable(struct usb_function *f)
378 {
379 	struct f_midi *midi = func_to_midi(f);
380 	struct usb_composite_dev *cdev = f->config->cdev;
381 
382 	DBG(cdev, "disable\n");
383 
384 	/*
385 	 * just disable endpoints, forcing completion of pending i/o.
386 	 * all our completion handlers free their requests in this case.
387 	 */
388 	usb_ep_disable(midi->in_ep);
389 	usb_ep_disable(midi->out_ep);
390 }
391 
392 static int f_midi_snd_free(struct snd_device *device)
393 {
394 	return 0;
395 }
396 
397 static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
398 					uint8_t p1, uint8_t p2, uint8_t p3)
399 {
400 	unsigned length = req->length;
401 	u8 *buf = (u8 *)req->buf + length;
402 
403 	buf[0] = p0;
404 	buf[1] = p1;
405 	buf[2] = p2;
406 	buf[3] = p3;
407 	req->length = length + 4;
408 }
409 
410 /*
411  * Converts MIDI commands to USB MIDI packets.
412  */
413 static void f_midi_transmit_byte(struct usb_request *req,
414 				 struct gmidi_in_port *port, uint8_t b)
415 {
416 	uint8_t p0 = port->cable << 4;
417 
418 	if (b >= 0xf8) {
419 		f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
420 	} else if (b >= 0xf0) {
421 		switch (b) {
422 		case 0xf0:
423 			port->data[0] = b;
424 			port->state = STATE_SYSEX_1;
425 			break;
426 		case 0xf1:
427 		case 0xf3:
428 			port->data[0] = b;
429 			port->state = STATE_1PARAM;
430 			break;
431 		case 0xf2:
432 			port->data[0] = b;
433 			port->state = STATE_2PARAM_1;
434 			break;
435 		case 0xf4:
436 		case 0xf5:
437 			port->state = STATE_UNKNOWN;
438 			break;
439 		case 0xf6:
440 			f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
441 			port->state = STATE_UNKNOWN;
442 			break;
443 		case 0xf7:
444 			switch (port->state) {
445 			case STATE_SYSEX_0:
446 				f_midi_transmit_packet(req,
447 					p0 | 0x05, 0xf7, 0, 0);
448 				break;
449 			case STATE_SYSEX_1:
450 				f_midi_transmit_packet(req,
451 					p0 | 0x06, port->data[0], 0xf7, 0);
452 				break;
453 			case STATE_SYSEX_2:
454 				f_midi_transmit_packet(req,
455 					p0 | 0x07, port->data[0],
456 					port->data[1], 0xf7);
457 				break;
458 			}
459 			port->state = STATE_UNKNOWN;
460 			break;
461 		}
462 	} else if (b >= 0x80) {
463 		port->data[0] = b;
464 		if (b >= 0xc0 && b <= 0xdf)
465 			port->state = STATE_1PARAM;
466 		else
467 			port->state = STATE_2PARAM_1;
468 	} else { /* b < 0x80 */
469 		switch (port->state) {
470 		case STATE_1PARAM:
471 			if (port->data[0] < 0xf0) {
472 				p0 |= port->data[0] >> 4;
473 			} else {
474 				p0 |= 0x02;
475 				port->state = STATE_UNKNOWN;
476 			}
477 			f_midi_transmit_packet(req, p0, port->data[0], b, 0);
478 			break;
479 		case STATE_2PARAM_1:
480 			port->data[1] = b;
481 			port->state = STATE_2PARAM_2;
482 			break;
483 		case STATE_2PARAM_2:
484 			if (port->data[0] < 0xf0) {
485 				p0 |= port->data[0] >> 4;
486 				port->state = STATE_2PARAM_1;
487 			} else {
488 				p0 |= 0x03;
489 				port->state = STATE_UNKNOWN;
490 			}
491 			f_midi_transmit_packet(req,
492 				p0, port->data[0], port->data[1], b);
493 			break;
494 		case STATE_SYSEX_0:
495 			port->data[0] = b;
496 			port->state = STATE_SYSEX_1;
497 			break;
498 		case STATE_SYSEX_1:
499 			port->data[1] = b;
500 			port->state = STATE_SYSEX_2;
501 			break;
502 		case STATE_SYSEX_2:
503 			f_midi_transmit_packet(req,
504 				p0 | 0x04, port->data[0], port->data[1], b);
505 			port->state = STATE_SYSEX_0;
506 			break;
507 		}
508 	}
509 }
510 
511 static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
512 {
513 	struct usb_ep *ep = midi->in_ep;
514 	int i;
515 
516 	if (!ep)
517 		return;
518 
519 	if (!req)
520 		req = midi_alloc_ep_req(ep, midi->buflen);
521 
522 	if (!req) {
523 		ERROR(midi, "%s: alloc_ep_request failed\n", __func__);
524 		return;
525 	}
526 	req->length = 0;
527 	req->complete = f_midi_complete;
528 
529 	for (i = 0; i < MAX_PORTS; i++) {
530 		struct gmidi_in_port *port = midi->in_port[i];
531 		struct snd_rawmidi_substream *substream = midi->in_substream[i];
532 
533 		if (!port || !port->active || !substream)
534 			continue;
535 
536 		while (req->length + 3 < midi->buflen) {
537 			uint8_t b;
538 			if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
539 				port->active = 0;
540 				break;
541 			}
542 			f_midi_transmit_byte(req, port, b);
543 		}
544 	}
545 
546 	if (req->length > 0)
547 		usb_ep_queue(ep, req, GFP_ATOMIC);
548 	else
549 		free_ep_req(ep, req);
550 }
551 
552 static void f_midi_in_tasklet(unsigned long data)
553 {
554 	struct f_midi *midi = (struct f_midi *) data;
555 	f_midi_transmit(midi, NULL);
556 }
557 
558 static int f_midi_in_open(struct snd_rawmidi_substream *substream)
559 {
560 	struct f_midi *midi = substream->rmidi->private_data;
561 
562 	if (!midi->in_port[substream->number])
563 		return -EINVAL;
564 
565 	VDBG(midi, "%s()\n", __func__);
566 	midi->in_substream[substream->number] = substream;
567 	midi->in_port[substream->number]->state = STATE_UNKNOWN;
568 	return 0;
569 }
570 
571 static int f_midi_in_close(struct snd_rawmidi_substream *substream)
572 {
573 	struct f_midi *midi = substream->rmidi->private_data;
574 
575 	VDBG(midi, "%s()\n", __func__);
576 	return 0;
577 }
578 
579 static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
580 {
581 	struct f_midi *midi = substream->rmidi->private_data;
582 
583 	if (!midi->in_port[substream->number])
584 		return;
585 
586 	VDBG(midi, "%s() %d\n", __func__, up);
587 	midi->in_port[substream->number]->active = up;
588 	if (up)
589 		tasklet_hi_schedule(&midi->tasklet);
590 }
591 
592 static int f_midi_out_open(struct snd_rawmidi_substream *substream)
593 {
594 	struct f_midi *midi = substream->rmidi->private_data;
595 
596 	if (substream->number >= MAX_PORTS)
597 		return -EINVAL;
598 
599 	VDBG(midi, "%s()\n", __func__);
600 	midi->out_substream[substream->number] = substream;
601 	return 0;
602 }
603 
604 static int f_midi_out_close(struct snd_rawmidi_substream *substream)
605 {
606 	struct f_midi *midi = substream->rmidi->private_data;
607 
608 	VDBG(midi, "%s()\n", __func__);
609 	return 0;
610 }
611 
612 static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
613 {
614 	struct f_midi *midi = substream->rmidi->private_data;
615 
616 	VDBG(midi, "%s()\n", __func__);
617 
618 	if (up)
619 		set_bit(substream->number, &midi->out_triggered);
620 	else
621 		clear_bit(substream->number, &midi->out_triggered);
622 }
623 
624 static struct snd_rawmidi_ops gmidi_in_ops = {
625 	.open = f_midi_in_open,
626 	.close = f_midi_in_close,
627 	.trigger = f_midi_in_trigger,
628 };
629 
630 static struct snd_rawmidi_ops gmidi_out_ops = {
631 	.open = f_midi_out_open,
632 	.close = f_midi_out_close,
633 	.trigger = f_midi_out_trigger
634 };
635 
636 static inline void f_midi_unregister_card(struct f_midi *midi)
637 {
638 	if (midi->card) {
639 		snd_card_free(midi->card);
640 		midi->card = NULL;
641 	}
642 }
643 
644 /* register as a sound "card" */
645 static int f_midi_register_card(struct f_midi *midi)
646 {
647 	struct snd_card *card;
648 	struct snd_rawmidi *rmidi;
649 	int err;
650 	static struct snd_device_ops ops = {
651 		.dev_free = f_midi_snd_free,
652 	};
653 
654 	err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
655 			   THIS_MODULE, 0, &card);
656 	if (err < 0) {
657 		ERROR(midi, "snd_card_new() failed\n");
658 		goto fail;
659 	}
660 	midi->card = card;
661 
662 	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
663 	if (err < 0) {
664 		ERROR(midi, "snd_device_new() failed: error %d\n", err);
665 		goto fail;
666 	}
667 
668 	strcpy(card->driver, f_midi_longname);
669 	strcpy(card->longname, f_midi_longname);
670 	strcpy(card->shortname, f_midi_shortname);
671 
672 	/* Set up rawmidi */
673 	snd_component_add(card, "MIDI");
674 	err = snd_rawmidi_new(card, card->longname, 0,
675 			      midi->out_ports, midi->in_ports, &rmidi);
676 	if (err < 0) {
677 		ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
678 		goto fail;
679 	}
680 	midi->rmidi = rmidi;
681 	strcpy(rmidi->name, card->shortname);
682 	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
683 			    SNDRV_RAWMIDI_INFO_INPUT |
684 			    SNDRV_RAWMIDI_INFO_DUPLEX;
685 	rmidi->private_data = midi;
686 
687 	/*
688 	 * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
689 	 * It's an upside-down world being a gadget.
690 	 */
691 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
692 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
693 
694 	/* register it - we're ready to go */
695 	err = snd_card_register(card);
696 	if (err < 0) {
697 		ERROR(midi, "snd_card_register() failed\n");
698 		goto fail;
699 	}
700 
701 	VDBG(midi, "%s() finished ok\n", __func__);
702 	return 0;
703 
704 fail:
705 	f_midi_unregister_card(midi);
706 	return err;
707 }
708 
709 /* MIDI function driver setup/binding */
710 
711 static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
712 {
713 	struct usb_descriptor_header **midi_function;
714 	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
715 	struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
716 	struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
717 	struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
718 	struct usb_composite_dev *cdev = c->cdev;
719 	struct f_midi *midi = func_to_midi(f);
720 	struct usb_string *us;
721 	int status, n, jack = 1, i = 0;
722 
723 	midi->gadget = cdev->gadget;
724 	tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
725 	status = f_midi_register_card(midi);
726 	if (status < 0)
727 		goto fail_register;
728 
729 	/* maybe allocate device-global string ID */
730 	us = usb_gstrings_attach(c->cdev, midi_strings,
731 				 ARRAY_SIZE(midi_string_defs));
732 	if (IS_ERR(us)) {
733 		status = PTR_ERR(us);
734 		goto fail;
735 	}
736 	ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
737 
738 	/* We have two interfaces, AudioControl and MIDIStreaming */
739 	status = usb_interface_id(c, f);
740 	if (status < 0)
741 		goto fail;
742 	ac_interface_desc.bInterfaceNumber = status;
743 
744 	status = usb_interface_id(c, f);
745 	if (status < 0)
746 		goto fail;
747 	ms_interface_desc.bInterfaceNumber = status;
748 	ac_header_desc.baInterfaceNr[0] = status;
749 
750 	status = -ENODEV;
751 
752 	/* allocate instance-specific endpoints */
753 	midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
754 	if (!midi->in_ep)
755 		goto fail;
756 	midi->in_ep->driver_data = cdev;	/* claim */
757 
758 	midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
759 	if (!midi->out_ep)
760 		goto fail;
761 	midi->out_ep->driver_data = cdev;	/* claim */
762 
763 	/* allocate temporary function list */
764 	midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(*midi_function),
765 				GFP_KERNEL);
766 	if (!midi_function) {
767 		status = -ENOMEM;
768 		goto fail;
769 	}
770 
771 	/*
772 	 * construct the function's descriptor set. As the number of
773 	 * input and output MIDI ports is configurable, we have to do
774 	 * it that way.
775 	 */
776 
777 	/* add the headers - these are always the same */
778 	midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
779 	midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
780 	midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
781 
782 	/* calculate the header's wTotalLength */
783 	n = USB_DT_MS_HEADER_SIZE
784 		+ (midi->in_ports + midi->out_ports) *
785 			(USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
786 	ms_header_desc.wTotalLength = cpu_to_le16(n);
787 
788 	midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
789 
790 	/* configure the external IN jacks, each linked to an embedded OUT jack */
791 	for (n = 0; n < midi->in_ports; n++) {
792 		struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
793 		struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
794 
795 		in_ext->bLength			= USB_DT_MIDI_IN_SIZE;
796 		in_ext->bDescriptorType		= USB_DT_CS_INTERFACE;
797 		in_ext->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
798 		in_ext->bJackType		= USB_MS_EXTERNAL;
799 		in_ext->bJackID			= jack++;
800 		in_ext->iJack			= 0;
801 		midi_function[i++] = (struct usb_descriptor_header *) in_ext;
802 
803 		out_emb->bLength		= USB_DT_MIDI_OUT_SIZE(1);
804 		out_emb->bDescriptorType	= USB_DT_CS_INTERFACE;
805 		out_emb->bDescriptorSubtype	= USB_MS_MIDI_OUT_JACK;
806 		out_emb->bJackType		= USB_MS_EMBEDDED;
807 		out_emb->bJackID		= jack++;
808 		out_emb->bNrInputPins		= 1;
809 		out_emb->pins[0].baSourcePin	= 1;
810 		out_emb->pins[0].baSourceID	= in_ext->bJackID;
811 		out_emb->iJack			= 0;
812 		midi_function[i++] = (struct usb_descriptor_header *) out_emb;
813 
814 		/* link it to the endpoint */
815 		ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
816 	}
817 
818 	/* configure the external OUT jacks, each linked to an embedded IN jack */
819 	for (n = 0; n < midi->out_ports; n++) {
820 		struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
821 		struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
822 
823 		in_emb->bLength			= USB_DT_MIDI_IN_SIZE;
824 		in_emb->bDescriptorType		= USB_DT_CS_INTERFACE;
825 		in_emb->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
826 		in_emb->bJackType		= USB_MS_EMBEDDED;
827 		in_emb->bJackID			= jack++;
828 		in_emb->iJack			= 0;
829 		midi_function[i++] = (struct usb_descriptor_header *) in_emb;
830 
831 		out_ext->bLength =		USB_DT_MIDI_OUT_SIZE(1);
832 		out_ext->bDescriptorType =	USB_DT_CS_INTERFACE;
833 		out_ext->bDescriptorSubtype =	USB_MS_MIDI_OUT_JACK;
834 		out_ext->bJackType =		USB_MS_EXTERNAL;
835 		out_ext->bJackID =		jack++;
836 		out_ext->bNrInputPins =		1;
837 		out_ext->iJack =		0;
838 		out_ext->pins[0].baSourceID =	in_emb->bJackID;
839 		out_ext->pins[0].baSourcePin =	1;
840 		midi_function[i++] = (struct usb_descriptor_header *) out_ext;
841 
842 		/* link it to the endpoint */
843 		ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
844 	}
845 
846 	/* configure the endpoint descriptors ... */
847 	ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
848 	ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
849 
850 	ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
851 	ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
852 
853 	/* ... and add them to the list */
854 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
855 	midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
856 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
857 	midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
858 	midi_function[i++] = NULL;
859 
860 	/*
861 	 * support all relevant hardware speeds... we expect that when
862 	 * hardware is dual speed, all bulk-capable endpoints work at
863 	 * both speeds
864 	 */
865 	/* copy descriptors, and track endpoint copies */
866 	f->fs_descriptors = usb_copy_descriptors(midi_function);
867 	if (!f->fs_descriptors)
868 		goto fail_f_midi;
869 
870 	if (gadget_is_dualspeed(c->cdev->gadget)) {
871 		bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
872 		bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
873 		f->hs_descriptors = usb_copy_descriptors(midi_function);
874 		if (!f->hs_descriptors)
875 			goto fail_f_midi;
876 	}
877 
878 	kfree(midi_function);
879 
880 	return 0;
881 
882 fail_f_midi:
883 	kfree(midi_function);
884 	usb_free_descriptors(f->hs_descriptors);
885 fail:
886 	f_midi_unregister_card(midi);
887 fail_register:
888 	/* we might as well release our claims on endpoints */
889 	if (midi->out_ep)
890 		midi->out_ep->driver_data = NULL;
891 	if (midi->in_ep)
892 		midi->in_ep->driver_data = NULL;
893 
894 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
895 
896 	return status;
897 }
898 
899 static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
900 {
901 	return container_of(to_config_group(item), struct f_midi_opts,
902 			    func_inst.group);
903 }
904 
905 CONFIGFS_ATTR_STRUCT(f_midi_opts);
906 CONFIGFS_ATTR_OPS(f_midi_opts);
907 
908 static void midi_attr_release(struct config_item *item)
909 {
910 	struct f_midi_opts *opts = to_f_midi_opts(item);
911 
912 	usb_put_function_instance(&opts->func_inst);
913 }
914 
915 static struct configfs_item_operations midi_item_ops = {
916 	.release	= midi_attr_release,
917 	.show_attribute	= f_midi_opts_attr_show,
918 	.store_attribute = f_midi_opts_attr_store,
919 };
920 
921 #define F_MIDI_OPT(name, test_limit, limit)				\
922 static ssize_t f_midi_opts_##name##_show(struct f_midi_opts *opts, char *page) \
923 {									\
924 	int result;							\
925 									\
926 	mutex_lock(&opts->lock);					\
927 	result = sprintf(page, "%d\n", opts->name);			\
928 	mutex_unlock(&opts->lock);					\
929 									\
930 	return result;							\
931 }									\
932 									\
933 static ssize_t f_midi_opts_##name##_store(struct f_midi_opts *opts,	\
934 					 const char *page, size_t len)	\
935 {									\
936 	int ret;							\
937 	u32 num;							\
938 									\
939 	mutex_lock(&opts->lock);					\
940 	if (opts->refcnt) {						\
941 		ret = -EBUSY;						\
942 		goto end;						\
943 	}								\
944 									\
945 	ret = kstrtou32(page, 0, &num);					\
946 	if (ret)							\
947 		goto end;						\
948 									\
949 	if (test_limit && num > limit) {				\
950 		ret = -EINVAL;						\
951 		goto end;						\
952 	}								\
953 	opts->name = num;						\
954 	ret = len;							\
955 									\
956 end:									\
957 	mutex_unlock(&opts->lock);					\
958 	return ret;							\
959 }									\
960 									\
961 static struct f_midi_opts_attribute f_midi_opts_##name =		\
962 	__CONFIGFS_ATTR(name, S_IRUGO | S_IWUSR, f_midi_opts_##name##_show, \
963 			f_midi_opts_##name##_store)
964 
965 F_MIDI_OPT(index, true, SNDRV_CARDS);
966 F_MIDI_OPT(buflen, false, 0);
967 F_MIDI_OPT(qlen, false, 0);
968 F_MIDI_OPT(in_ports, true, MAX_PORTS);
969 F_MIDI_OPT(out_ports, true, MAX_PORTS);
970 
971 static ssize_t f_midi_opts_id_show(struct f_midi_opts *opts, char *page)
972 {
973 	int result;
974 
975 	mutex_lock(&opts->lock);
976 	result = strlcpy(page, opts->id, PAGE_SIZE);
977 	mutex_unlock(&opts->lock);
978 
979 	return result;
980 }
981 
982 static ssize_t f_midi_opts_id_store(struct f_midi_opts *opts,
983 				    const char *page, size_t len)
984 {
985 	int ret;
986 	char *c;
987 
988 	mutex_lock(&opts->lock);
989 	if (opts->refcnt) {
990 		ret = -EBUSY;
991 		goto end;
992 	}
993 
994 	c = kstrndup(page, len, GFP_KERNEL);
995 	if (!c) {
996 		ret = -ENOMEM;
997 		goto end;
998 	}
999 	if (opts->id_allocated)
1000 		kfree(opts->id);
1001 	opts->id = c;
1002 	opts->id_allocated = true;
1003 	ret = len;
1004 end:
1005 	mutex_unlock(&opts->lock);
1006 	return ret;
1007 }
1008 
1009 static struct f_midi_opts_attribute f_midi_opts_id =
1010 	__CONFIGFS_ATTR(id, S_IRUGO | S_IWUSR, f_midi_opts_id_show,
1011 			f_midi_opts_id_store);
1012 
1013 static struct configfs_attribute *midi_attrs[] = {
1014 	&f_midi_opts_index.attr,
1015 	&f_midi_opts_buflen.attr,
1016 	&f_midi_opts_qlen.attr,
1017 	&f_midi_opts_in_ports.attr,
1018 	&f_midi_opts_out_ports.attr,
1019 	&f_midi_opts_id.attr,
1020 	NULL,
1021 };
1022 
1023 static struct config_item_type midi_func_type = {
1024 	.ct_item_ops	= &midi_item_ops,
1025 	.ct_attrs	= midi_attrs,
1026 	.ct_owner	= THIS_MODULE,
1027 };
1028 
1029 static void f_midi_free_inst(struct usb_function_instance *f)
1030 {
1031 	struct f_midi_opts *opts;
1032 
1033 	opts = container_of(f, struct f_midi_opts, func_inst);
1034 
1035 	if (opts->id_allocated)
1036 		kfree(opts->id);
1037 
1038 	kfree(opts);
1039 }
1040 
1041 static struct usb_function_instance *f_midi_alloc_inst(void)
1042 {
1043 	struct f_midi_opts *opts;
1044 
1045 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1046 	if (!opts)
1047 		return ERR_PTR(-ENOMEM);
1048 
1049 	mutex_init(&opts->lock);
1050 	opts->func_inst.free_func_inst = f_midi_free_inst;
1051 	opts->index = SNDRV_DEFAULT_IDX1;
1052 	opts->id = SNDRV_DEFAULT_STR1;
1053 	opts->buflen = 256;
1054 	opts->qlen = 32;
1055 	opts->in_ports = 1;
1056 	opts->out_ports = 1;
1057 
1058 	config_group_init_type_name(&opts->func_inst.group, "",
1059 				    &midi_func_type);
1060 
1061 	return &opts->func_inst;
1062 }
1063 
1064 static void f_midi_free(struct usb_function *f)
1065 {
1066 	struct f_midi *midi;
1067 	struct f_midi_opts *opts;
1068 	int i;
1069 
1070 	midi = func_to_midi(f);
1071 	opts = container_of(f->fi, struct f_midi_opts, func_inst);
1072 	kfree(midi->id);
1073 	mutex_lock(&opts->lock);
1074 	for (i = opts->in_ports - 1; i >= 0; --i)
1075 		kfree(midi->in_port[i]);
1076 	kfree(midi);
1077 	--opts->refcnt;
1078 	mutex_unlock(&opts->lock);
1079 }
1080 
1081 static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
1082 {
1083 	struct usb_composite_dev *cdev = f->config->cdev;
1084 	struct f_midi *midi = func_to_midi(f);
1085 	struct snd_card *card;
1086 
1087 	DBG(cdev, "unbind\n");
1088 
1089 	/* just to be sure */
1090 	f_midi_disable(f);
1091 
1092 	card = midi->card;
1093 	midi->card = NULL;
1094 	if (card)
1095 		snd_card_free(card);
1096 
1097 	usb_free_all_descriptors(f);
1098 }
1099 
1100 static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
1101 {
1102 	struct f_midi *midi;
1103 	struct f_midi_opts *opts;
1104 	int status, i;
1105 
1106 	opts = container_of(fi, struct f_midi_opts, func_inst);
1107 
1108 	mutex_lock(&opts->lock);
1109 	/* sanity check */
1110 	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
1111 		mutex_unlock(&opts->lock);
1112 		return ERR_PTR(-EINVAL);
1113 	}
1114 
1115 	/* allocate and initialize one new instance */
1116 	midi = kzalloc(sizeof(*midi), GFP_KERNEL);
1117 	if (!midi) {
1118 		mutex_unlock(&opts->lock);
1119 		return ERR_PTR(-ENOMEM);
1120 	}
1121 
1122 	for (i = 0; i < opts->in_ports; i++) {
1123 		struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
1124 
1125 		if (!port) {
1126 			status = -ENOMEM;
1127 			mutex_unlock(&opts->lock);
1128 			goto setup_fail;
1129 		}
1130 
1131 		port->midi = midi;
1132 		port->active = 0;
1133 		port->cable = i;
1134 		midi->in_port[i] = port;
1135 	}
1136 
1137 	/* set up ALSA midi devices */
1138 	midi->id = kstrdup(opts->id, GFP_KERNEL);
1139 	if (opts->id && !midi->id) {
1140 		status = -ENOMEM;
1141 		mutex_unlock(&opts->lock);
1142 		goto kstrdup_fail;
1143 	}
1144 	midi->in_ports = opts->in_ports;
1145 	midi->out_ports = opts->out_ports;
1146 	midi->index = opts->index;
1147 	midi->buflen = opts->buflen;
1148 	midi->qlen = opts->qlen;
1149 	++opts->refcnt;
1150 	mutex_unlock(&opts->lock);
1151 
1152 	midi->func.name		= "gmidi function";
1153 	midi->func.bind		= f_midi_bind;
1154 	midi->func.unbind	= f_midi_unbind;
1155 	midi->func.set_alt	= f_midi_set_alt;
1156 	midi->func.disable	= f_midi_disable;
1157 	midi->func.free_func	= f_midi_free;
1158 
1159 	return &midi->func;
1160 
1161 kstrdup_fail:
1162 	f_midi_unregister_card(midi);
1163 setup_fail:
1164 	for (--i; i >= 0; i--)
1165 		kfree(midi->in_port[i]);
1166 	kfree(midi);
1167 	return ERR_PTR(status);
1168 }
1169 
1170 DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);
1171