xref: /linux/drivers/usb/gadget/function/f_midi.c (revision 9da8320bb97768e35f2e64fa7642015271d672eb)
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 	usb_ep_disable(ep);
306 
307 	err = config_ep_by_speed(midi->gadget, f, ep);
308 	if (err) {
309 		ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
310 		return err;
311 	}
312 
313 	err = usb_ep_enable(ep);
314 	if (err) {
315 		ERROR(cdev, "can't start %s: %d\n", ep->name, err);
316 		return err;
317 	}
318 
319 	ep->driver_data = midi;
320 
321 	return 0;
322 }
323 
324 static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
325 {
326 	struct f_midi *midi = func_to_midi(f);
327 	struct usb_composite_dev *cdev = f->config->cdev;
328 	unsigned i;
329 	int err;
330 
331 	/* For Control Device interface we do nothing */
332 	if (intf == 0)
333 		return 0;
334 
335 	err = f_midi_start_ep(midi, f, midi->in_ep);
336 	if (err)
337 		return err;
338 
339 	err = f_midi_start_ep(midi, f, midi->out_ep);
340 	if (err)
341 		return err;
342 
343 	usb_ep_disable(midi->out_ep);
344 
345 	err = config_ep_by_speed(midi->gadget, f, midi->out_ep);
346 	if (err) {
347 		ERROR(cdev, "can't configure %s: %d\n",
348 		      midi->out_ep->name, err);
349 		return err;
350 	}
351 
352 	err = usb_ep_enable(midi->out_ep);
353 	if (err) {
354 		ERROR(cdev, "can't start %s: %d\n",
355 		      midi->out_ep->name, err);
356 		return err;
357 	}
358 
359 	midi->out_ep->driver_data = midi;
360 
361 	/* allocate a bunch of read buffers and queue them all at once. */
362 	for (i = 0; i < midi->qlen && err == 0; i++) {
363 		struct usb_request *req =
364 			midi_alloc_ep_req(midi->out_ep, midi->buflen);
365 		if (req == NULL)
366 			return -ENOMEM;
367 
368 		req->complete = f_midi_complete;
369 		err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
370 		if (err) {
371 			ERROR(midi, "%s queue req: %d\n",
372 				    midi->out_ep->name, err);
373 			free_ep_req(midi->out_ep, req);
374 		}
375 	}
376 
377 	return 0;
378 }
379 
380 static void f_midi_disable(struct usb_function *f)
381 {
382 	struct f_midi *midi = func_to_midi(f);
383 	struct usb_composite_dev *cdev = f->config->cdev;
384 
385 	DBG(cdev, "disable\n");
386 
387 	/*
388 	 * just disable endpoints, forcing completion of pending i/o.
389 	 * all our completion handlers free their requests in this case.
390 	 */
391 	usb_ep_disable(midi->in_ep);
392 	usb_ep_disable(midi->out_ep);
393 }
394 
395 static int f_midi_snd_free(struct snd_device *device)
396 {
397 	return 0;
398 }
399 
400 static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
401 					uint8_t p1, uint8_t p2, uint8_t p3)
402 {
403 	unsigned length = req->length;
404 	u8 *buf = (u8 *)req->buf + length;
405 
406 	buf[0] = p0;
407 	buf[1] = p1;
408 	buf[2] = p2;
409 	buf[3] = p3;
410 	req->length = length + 4;
411 }
412 
413 /*
414  * Converts MIDI commands to USB MIDI packets.
415  */
416 static void f_midi_transmit_byte(struct usb_request *req,
417 				 struct gmidi_in_port *port, uint8_t b)
418 {
419 	uint8_t p0 = port->cable << 4;
420 
421 	if (b >= 0xf8) {
422 		f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
423 	} else if (b >= 0xf0) {
424 		switch (b) {
425 		case 0xf0:
426 			port->data[0] = b;
427 			port->state = STATE_SYSEX_1;
428 			break;
429 		case 0xf1:
430 		case 0xf3:
431 			port->data[0] = b;
432 			port->state = STATE_1PARAM;
433 			break;
434 		case 0xf2:
435 			port->data[0] = b;
436 			port->state = STATE_2PARAM_1;
437 			break;
438 		case 0xf4:
439 		case 0xf5:
440 			port->state = STATE_UNKNOWN;
441 			break;
442 		case 0xf6:
443 			f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
444 			port->state = STATE_UNKNOWN;
445 			break;
446 		case 0xf7:
447 			switch (port->state) {
448 			case STATE_SYSEX_0:
449 				f_midi_transmit_packet(req,
450 					p0 | 0x05, 0xf7, 0, 0);
451 				break;
452 			case STATE_SYSEX_1:
453 				f_midi_transmit_packet(req,
454 					p0 | 0x06, port->data[0], 0xf7, 0);
455 				break;
456 			case STATE_SYSEX_2:
457 				f_midi_transmit_packet(req,
458 					p0 | 0x07, port->data[0],
459 					port->data[1], 0xf7);
460 				break;
461 			}
462 			port->state = STATE_UNKNOWN;
463 			break;
464 		}
465 	} else if (b >= 0x80) {
466 		port->data[0] = b;
467 		if (b >= 0xc0 && b <= 0xdf)
468 			port->state = STATE_1PARAM;
469 		else
470 			port->state = STATE_2PARAM_1;
471 	} else { /* b < 0x80 */
472 		switch (port->state) {
473 		case STATE_1PARAM:
474 			if (port->data[0] < 0xf0) {
475 				p0 |= port->data[0] >> 4;
476 			} else {
477 				p0 |= 0x02;
478 				port->state = STATE_UNKNOWN;
479 			}
480 			f_midi_transmit_packet(req, p0, port->data[0], b, 0);
481 			break;
482 		case STATE_2PARAM_1:
483 			port->data[1] = b;
484 			port->state = STATE_2PARAM_2;
485 			break;
486 		case STATE_2PARAM_2:
487 			if (port->data[0] < 0xf0) {
488 				p0 |= port->data[0] >> 4;
489 				port->state = STATE_2PARAM_1;
490 			} else {
491 				p0 |= 0x03;
492 				port->state = STATE_UNKNOWN;
493 			}
494 			f_midi_transmit_packet(req,
495 				p0, port->data[0], port->data[1], b);
496 			break;
497 		case STATE_SYSEX_0:
498 			port->data[0] = b;
499 			port->state = STATE_SYSEX_1;
500 			break;
501 		case STATE_SYSEX_1:
502 			port->data[1] = b;
503 			port->state = STATE_SYSEX_2;
504 			break;
505 		case STATE_SYSEX_2:
506 			f_midi_transmit_packet(req,
507 				p0 | 0x04, port->data[0], port->data[1], b);
508 			port->state = STATE_SYSEX_0;
509 			break;
510 		}
511 	}
512 }
513 
514 static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
515 {
516 	struct usb_ep *ep = midi->in_ep;
517 	int i;
518 
519 	if (!ep)
520 		return;
521 
522 	if (!req)
523 		req = midi_alloc_ep_req(ep, midi->buflen);
524 
525 	if (!req) {
526 		ERROR(midi, "%s: alloc_ep_request failed\n", __func__);
527 		return;
528 	}
529 	req->length = 0;
530 	req->complete = f_midi_complete;
531 
532 	for (i = 0; i < MAX_PORTS; i++) {
533 		struct gmidi_in_port *port = midi->in_port[i];
534 		struct snd_rawmidi_substream *substream = midi->in_substream[i];
535 
536 		if (!port || !port->active || !substream)
537 			continue;
538 
539 		while (req->length + 3 < midi->buflen) {
540 			uint8_t b;
541 			if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
542 				port->active = 0;
543 				break;
544 			}
545 			f_midi_transmit_byte(req, port, b);
546 		}
547 	}
548 
549 	if (req->length > 0 && ep->enabled) {
550 		int err;
551 
552 		err = usb_ep_queue(ep, req, GFP_ATOMIC);
553 		if (err < 0)
554 			ERROR(midi, "%s queue req: %d\n",
555 			      midi->in_ep->name, err);
556 	} else {
557 		free_ep_req(ep, req);
558 	}
559 }
560 
561 static void f_midi_in_tasklet(unsigned long data)
562 {
563 	struct f_midi *midi = (struct f_midi *) data;
564 	f_midi_transmit(midi, NULL);
565 }
566 
567 static int f_midi_in_open(struct snd_rawmidi_substream *substream)
568 {
569 	struct f_midi *midi = substream->rmidi->private_data;
570 
571 	if (!midi->in_port[substream->number])
572 		return -EINVAL;
573 
574 	VDBG(midi, "%s()\n", __func__);
575 	midi->in_substream[substream->number] = substream;
576 	midi->in_port[substream->number]->state = STATE_UNKNOWN;
577 	return 0;
578 }
579 
580 static int f_midi_in_close(struct snd_rawmidi_substream *substream)
581 {
582 	struct f_midi *midi = substream->rmidi->private_data;
583 
584 	VDBG(midi, "%s()\n", __func__);
585 	return 0;
586 }
587 
588 static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
589 {
590 	struct f_midi *midi = substream->rmidi->private_data;
591 
592 	if (!midi->in_port[substream->number])
593 		return;
594 
595 	VDBG(midi, "%s() %d\n", __func__, up);
596 	midi->in_port[substream->number]->active = up;
597 	if (up)
598 		tasklet_hi_schedule(&midi->tasklet);
599 }
600 
601 static int f_midi_out_open(struct snd_rawmidi_substream *substream)
602 {
603 	struct f_midi *midi = substream->rmidi->private_data;
604 
605 	if (substream->number >= MAX_PORTS)
606 		return -EINVAL;
607 
608 	VDBG(midi, "%s()\n", __func__);
609 	midi->out_substream[substream->number] = substream;
610 	return 0;
611 }
612 
613 static int f_midi_out_close(struct snd_rawmidi_substream *substream)
614 {
615 	struct f_midi *midi = substream->rmidi->private_data;
616 
617 	VDBG(midi, "%s()\n", __func__);
618 	return 0;
619 }
620 
621 static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
622 {
623 	struct f_midi *midi = substream->rmidi->private_data;
624 
625 	VDBG(midi, "%s()\n", __func__);
626 
627 	if (up)
628 		set_bit(substream->number, &midi->out_triggered);
629 	else
630 		clear_bit(substream->number, &midi->out_triggered);
631 }
632 
633 static struct snd_rawmidi_ops gmidi_in_ops = {
634 	.open = f_midi_in_open,
635 	.close = f_midi_in_close,
636 	.trigger = f_midi_in_trigger,
637 };
638 
639 static struct snd_rawmidi_ops gmidi_out_ops = {
640 	.open = f_midi_out_open,
641 	.close = f_midi_out_close,
642 	.trigger = f_midi_out_trigger
643 };
644 
645 static inline void f_midi_unregister_card(struct f_midi *midi)
646 {
647 	if (midi->card) {
648 		snd_card_free(midi->card);
649 		midi->card = NULL;
650 	}
651 }
652 
653 /* register as a sound "card" */
654 static int f_midi_register_card(struct f_midi *midi)
655 {
656 	struct snd_card *card;
657 	struct snd_rawmidi *rmidi;
658 	int err;
659 	static struct snd_device_ops ops = {
660 		.dev_free = f_midi_snd_free,
661 	};
662 
663 	err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
664 			   THIS_MODULE, 0, &card);
665 	if (err < 0) {
666 		ERROR(midi, "snd_card_new() failed\n");
667 		goto fail;
668 	}
669 	midi->card = card;
670 
671 	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
672 	if (err < 0) {
673 		ERROR(midi, "snd_device_new() failed: error %d\n", err);
674 		goto fail;
675 	}
676 
677 	strcpy(card->driver, f_midi_longname);
678 	strcpy(card->longname, f_midi_longname);
679 	strcpy(card->shortname, f_midi_shortname);
680 
681 	/* Set up rawmidi */
682 	snd_component_add(card, "MIDI");
683 	err = snd_rawmidi_new(card, card->longname, 0,
684 			      midi->out_ports, midi->in_ports, &rmidi);
685 	if (err < 0) {
686 		ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
687 		goto fail;
688 	}
689 	midi->rmidi = rmidi;
690 	strcpy(rmidi->name, card->shortname);
691 	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
692 			    SNDRV_RAWMIDI_INFO_INPUT |
693 			    SNDRV_RAWMIDI_INFO_DUPLEX;
694 	rmidi->private_data = midi;
695 
696 	/*
697 	 * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
698 	 * It's an upside-down world being a gadget.
699 	 */
700 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
701 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
702 
703 	/* register it - we're ready to go */
704 	err = snd_card_register(card);
705 	if (err < 0) {
706 		ERROR(midi, "snd_card_register() failed\n");
707 		goto fail;
708 	}
709 
710 	VDBG(midi, "%s() finished ok\n", __func__);
711 	return 0;
712 
713 fail:
714 	f_midi_unregister_card(midi);
715 	return err;
716 }
717 
718 /* MIDI function driver setup/binding */
719 
720 static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
721 {
722 	struct usb_descriptor_header **midi_function;
723 	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
724 	struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
725 	struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
726 	struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
727 	struct usb_composite_dev *cdev = c->cdev;
728 	struct f_midi *midi = func_to_midi(f);
729 	struct usb_string *us;
730 	int status, n, jack = 1, i = 0;
731 
732 	midi->gadget = cdev->gadget;
733 	tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
734 	status = f_midi_register_card(midi);
735 	if (status < 0)
736 		goto fail_register;
737 
738 	/* maybe allocate device-global string ID */
739 	us = usb_gstrings_attach(c->cdev, midi_strings,
740 				 ARRAY_SIZE(midi_string_defs));
741 	if (IS_ERR(us)) {
742 		status = PTR_ERR(us);
743 		goto fail;
744 	}
745 	ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
746 
747 	/* We have two interfaces, AudioControl and MIDIStreaming */
748 	status = usb_interface_id(c, f);
749 	if (status < 0)
750 		goto fail;
751 	ac_interface_desc.bInterfaceNumber = status;
752 
753 	status = usb_interface_id(c, f);
754 	if (status < 0)
755 		goto fail;
756 	ms_interface_desc.bInterfaceNumber = status;
757 	ac_header_desc.baInterfaceNr[0] = status;
758 
759 	status = -ENODEV;
760 
761 	/* allocate instance-specific endpoints */
762 	midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
763 	if (!midi->in_ep)
764 		goto fail;
765 
766 	midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
767 	if (!midi->out_ep)
768 		goto fail;
769 
770 	/* allocate temporary function list */
771 	midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(*midi_function),
772 				GFP_KERNEL);
773 	if (!midi_function) {
774 		status = -ENOMEM;
775 		goto fail;
776 	}
777 
778 	/*
779 	 * construct the function's descriptor set. As the number of
780 	 * input and output MIDI ports is configurable, we have to do
781 	 * it that way.
782 	 */
783 
784 	/* add the headers - these are always the same */
785 	midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
786 	midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
787 	midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
788 
789 	/* calculate the header's wTotalLength */
790 	n = USB_DT_MS_HEADER_SIZE
791 		+ (midi->in_ports + midi->out_ports) *
792 			(USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
793 	ms_header_desc.wTotalLength = cpu_to_le16(n);
794 
795 	midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
796 
797 	/* configure the external IN jacks, each linked to an embedded OUT jack */
798 	for (n = 0; n < midi->in_ports; n++) {
799 		struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
800 		struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
801 
802 		in_ext->bLength			= USB_DT_MIDI_IN_SIZE;
803 		in_ext->bDescriptorType		= USB_DT_CS_INTERFACE;
804 		in_ext->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
805 		in_ext->bJackType		= USB_MS_EXTERNAL;
806 		in_ext->bJackID			= jack++;
807 		in_ext->iJack			= 0;
808 		midi_function[i++] = (struct usb_descriptor_header *) in_ext;
809 
810 		out_emb->bLength		= USB_DT_MIDI_OUT_SIZE(1);
811 		out_emb->bDescriptorType	= USB_DT_CS_INTERFACE;
812 		out_emb->bDescriptorSubtype	= USB_MS_MIDI_OUT_JACK;
813 		out_emb->bJackType		= USB_MS_EMBEDDED;
814 		out_emb->bJackID		= jack++;
815 		out_emb->bNrInputPins		= 1;
816 		out_emb->pins[0].baSourcePin	= 1;
817 		out_emb->pins[0].baSourceID	= in_ext->bJackID;
818 		out_emb->iJack			= 0;
819 		midi_function[i++] = (struct usb_descriptor_header *) out_emb;
820 
821 		/* link it to the endpoint */
822 		ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
823 	}
824 
825 	/* configure the external OUT jacks, each linked to an embedded IN jack */
826 	for (n = 0; n < midi->out_ports; n++) {
827 		struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
828 		struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
829 
830 		in_emb->bLength			= USB_DT_MIDI_IN_SIZE;
831 		in_emb->bDescriptorType		= USB_DT_CS_INTERFACE;
832 		in_emb->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
833 		in_emb->bJackType		= USB_MS_EMBEDDED;
834 		in_emb->bJackID			= jack++;
835 		in_emb->iJack			= 0;
836 		midi_function[i++] = (struct usb_descriptor_header *) in_emb;
837 
838 		out_ext->bLength =		USB_DT_MIDI_OUT_SIZE(1);
839 		out_ext->bDescriptorType =	USB_DT_CS_INTERFACE;
840 		out_ext->bDescriptorSubtype =	USB_MS_MIDI_OUT_JACK;
841 		out_ext->bJackType =		USB_MS_EXTERNAL;
842 		out_ext->bJackID =		jack++;
843 		out_ext->bNrInputPins =		1;
844 		out_ext->iJack =		0;
845 		out_ext->pins[0].baSourceID =	in_emb->bJackID;
846 		out_ext->pins[0].baSourcePin =	1;
847 		midi_function[i++] = (struct usb_descriptor_header *) out_ext;
848 
849 		/* link it to the endpoint */
850 		ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
851 	}
852 
853 	/* configure the endpoint descriptors ... */
854 	ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
855 	ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
856 
857 	ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
858 	ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
859 
860 	/* ... and add them to the list */
861 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
862 	midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
863 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
864 	midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
865 	midi_function[i++] = NULL;
866 
867 	/*
868 	 * support all relevant hardware speeds... we expect that when
869 	 * hardware is dual speed, all bulk-capable endpoints work at
870 	 * both speeds
871 	 */
872 	/* copy descriptors, and track endpoint copies */
873 	f->fs_descriptors = usb_copy_descriptors(midi_function);
874 	if (!f->fs_descriptors)
875 		goto fail_f_midi;
876 
877 	if (gadget_is_dualspeed(c->cdev->gadget)) {
878 		bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
879 		bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
880 		f->hs_descriptors = usb_copy_descriptors(midi_function);
881 		if (!f->hs_descriptors)
882 			goto fail_f_midi;
883 	}
884 
885 	kfree(midi_function);
886 
887 	return 0;
888 
889 fail_f_midi:
890 	kfree(midi_function);
891 	usb_free_descriptors(f->hs_descriptors);
892 fail:
893 	f_midi_unregister_card(midi);
894 fail_register:
895 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
896 
897 	return status;
898 }
899 
900 static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
901 {
902 	return container_of(to_config_group(item), struct f_midi_opts,
903 			    func_inst.group);
904 }
905 
906 static void midi_attr_release(struct config_item *item)
907 {
908 	struct f_midi_opts *opts = to_f_midi_opts(item);
909 
910 	usb_put_function_instance(&opts->func_inst);
911 }
912 
913 static struct configfs_item_operations midi_item_ops = {
914 	.release	= midi_attr_release,
915 };
916 
917 #define F_MIDI_OPT(name, test_limit, limit)				\
918 static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
919 {									\
920 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
921 	int result;							\
922 									\
923 	mutex_lock(&opts->lock);					\
924 	result = sprintf(page, "%d\n", opts->name);			\
925 	mutex_unlock(&opts->lock);					\
926 									\
927 	return result;							\
928 }									\
929 									\
930 static ssize_t f_midi_opts_##name##_store(struct config_item *item,	\
931 					 const char *page, size_t len)	\
932 {									\
933 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
934 	int ret;							\
935 	u32 num;							\
936 									\
937 	mutex_lock(&opts->lock);					\
938 	if (opts->refcnt) {						\
939 		ret = -EBUSY;						\
940 		goto end;						\
941 	}								\
942 									\
943 	ret = kstrtou32(page, 0, &num);					\
944 	if (ret)							\
945 		goto end;						\
946 									\
947 	if (test_limit && num > limit) {				\
948 		ret = -EINVAL;						\
949 		goto end;						\
950 	}								\
951 	opts->name = num;						\
952 	ret = len;							\
953 									\
954 end:									\
955 	mutex_unlock(&opts->lock);					\
956 	return ret;							\
957 }									\
958 									\
959 CONFIGFS_ATTR(f_midi_opts_, name);
960 
961 F_MIDI_OPT(index, true, SNDRV_CARDS);
962 F_MIDI_OPT(buflen, false, 0);
963 F_MIDI_OPT(qlen, false, 0);
964 F_MIDI_OPT(in_ports, true, MAX_PORTS);
965 F_MIDI_OPT(out_ports, true, MAX_PORTS);
966 
967 static ssize_t f_midi_opts_id_show(struct config_item *item, char *page)
968 {
969 	struct f_midi_opts *opts = to_f_midi_opts(item);
970 	int result;
971 
972 	mutex_lock(&opts->lock);
973 	if (opts->id) {
974 		result = strlcpy(page, opts->id, PAGE_SIZE);
975 	} else {
976 		page[0] = 0;
977 		result = 0;
978 	}
979 
980 	mutex_unlock(&opts->lock);
981 
982 	return result;
983 }
984 
985 static ssize_t f_midi_opts_id_store(struct config_item *item,
986 				    const char *page, size_t len)
987 {
988 	struct f_midi_opts *opts = to_f_midi_opts(item);
989 	int ret;
990 	char *c;
991 
992 	mutex_lock(&opts->lock);
993 	if (opts->refcnt) {
994 		ret = -EBUSY;
995 		goto end;
996 	}
997 
998 	c = kstrndup(page, len, GFP_KERNEL);
999 	if (!c) {
1000 		ret = -ENOMEM;
1001 		goto end;
1002 	}
1003 	if (opts->id_allocated)
1004 		kfree(opts->id);
1005 	opts->id = c;
1006 	opts->id_allocated = true;
1007 	ret = len;
1008 end:
1009 	mutex_unlock(&opts->lock);
1010 	return ret;
1011 }
1012 
1013 CONFIGFS_ATTR(f_midi_opts_, id);
1014 
1015 static struct configfs_attribute *midi_attrs[] = {
1016 	&f_midi_opts_attr_index,
1017 	&f_midi_opts_attr_buflen,
1018 	&f_midi_opts_attr_qlen,
1019 	&f_midi_opts_attr_in_ports,
1020 	&f_midi_opts_attr_out_ports,
1021 	&f_midi_opts_attr_id,
1022 	NULL,
1023 };
1024 
1025 static struct config_item_type midi_func_type = {
1026 	.ct_item_ops	= &midi_item_ops,
1027 	.ct_attrs	= midi_attrs,
1028 	.ct_owner	= THIS_MODULE,
1029 };
1030 
1031 static void f_midi_free_inst(struct usb_function_instance *f)
1032 {
1033 	struct f_midi_opts *opts;
1034 
1035 	opts = container_of(f, struct f_midi_opts, func_inst);
1036 
1037 	if (opts->id_allocated)
1038 		kfree(opts->id);
1039 
1040 	kfree(opts);
1041 }
1042 
1043 static struct usb_function_instance *f_midi_alloc_inst(void)
1044 {
1045 	struct f_midi_opts *opts;
1046 
1047 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1048 	if (!opts)
1049 		return ERR_PTR(-ENOMEM);
1050 
1051 	mutex_init(&opts->lock);
1052 	opts->func_inst.free_func_inst = f_midi_free_inst;
1053 	opts->index = SNDRV_DEFAULT_IDX1;
1054 	opts->id = SNDRV_DEFAULT_STR1;
1055 	opts->buflen = 256;
1056 	opts->qlen = 32;
1057 	opts->in_ports = 1;
1058 	opts->out_ports = 1;
1059 
1060 	config_group_init_type_name(&opts->func_inst.group, "",
1061 				    &midi_func_type);
1062 
1063 	return &opts->func_inst;
1064 }
1065 
1066 static void f_midi_free(struct usb_function *f)
1067 {
1068 	struct f_midi *midi;
1069 	struct f_midi_opts *opts;
1070 	int i;
1071 
1072 	midi = func_to_midi(f);
1073 	opts = container_of(f->fi, struct f_midi_opts, func_inst);
1074 	kfree(midi->id);
1075 	mutex_lock(&opts->lock);
1076 	for (i = opts->in_ports - 1; i >= 0; --i)
1077 		kfree(midi->in_port[i]);
1078 	kfree(midi);
1079 	--opts->refcnt;
1080 	mutex_unlock(&opts->lock);
1081 }
1082 
1083 static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
1084 {
1085 	struct usb_composite_dev *cdev = f->config->cdev;
1086 	struct f_midi *midi = func_to_midi(f);
1087 	struct snd_card *card;
1088 
1089 	DBG(cdev, "unbind\n");
1090 
1091 	/* just to be sure */
1092 	f_midi_disable(f);
1093 
1094 	card = midi->card;
1095 	midi->card = NULL;
1096 	if (card)
1097 		snd_card_free(card);
1098 
1099 	usb_free_all_descriptors(f);
1100 }
1101 
1102 static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
1103 {
1104 	struct f_midi *midi;
1105 	struct f_midi_opts *opts;
1106 	int status, i;
1107 
1108 	opts = container_of(fi, struct f_midi_opts, func_inst);
1109 
1110 	mutex_lock(&opts->lock);
1111 	/* sanity check */
1112 	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
1113 		mutex_unlock(&opts->lock);
1114 		return ERR_PTR(-EINVAL);
1115 	}
1116 
1117 	/* allocate and initialize one new instance */
1118 	midi = kzalloc(sizeof(*midi), GFP_KERNEL);
1119 	if (!midi) {
1120 		mutex_unlock(&opts->lock);
1121 		return ERR_PTR(-ENOMEM);
1122 	}
1123 
1124 	for (i = 0; i < opts->in_ports; i++) {
1125 		struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
1126 
1127 		if (!port) {
1128 			status = -ENOMEM;
1129 			mutex_unlock(&opts->lock);
1130 			goto setup_fail;
1131 		}
1132 
1133 		port->midi = midi;
1134 		port->active = 0;
1135 		port->cable = i;
1136 		midi->in_port[i] = port;
1137 	}
1138 
1139 	/* set up ALSA midi devices */
1140 	midi->id = kstrdup(opts->id, GFP_KERNEL);
1141 	if (opts->id && !midi->id) {
1142 		status = -ENOMEM;
1143 		mutex_unlock(&opts->lock);
1144 		goto setup_fail;
1145 	}
1146 	midi->in_ports = opts->in_ports;
1147 	midi->out_ports = opts->out_ports;
1148 	midi->index = opts->index;
1149 	midi->buflen = opts->buflen;
1150 	midi->qlen = opts->qlen;
1151 	++opts->refcnt;
1152 	mutex_unlock(&opts->lock);
1153 
1154 	midi->func.name		= "gmidi function";
1155 	midi->func.bind		= f_midi_bind;
1156 	midi->func.unbind	= f_midi_unbind;
1157 	midi->func.set_alt	= f_midi_set_alt;
1158 	midi->func.disable	= f_midi_disable;
1159 	midi->func.free_func	= f_midi_free;
1160 
1161 	return &midi->func;
1162 
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