xref: /openbmc/linux/drivers/usb/gadget/function/f_midi.c (revision 029f7f3b8701cc7aca8bdb31f0c7edd6a479e357)
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 		}
374 	}
375 
376 	return 0;
377 }
378 
379 static void f_midi_disable(struct usb_function *f)
380 {
381 	struct f_midi *midi = func_to_midi(f);
382 	struct usb_composite_dev *cdev = f->config->cdev;
383 
384 	DBG(cdev, "disable\n");
385 
386 	/*
387 	 * just disable endpoints, forcing completion of pending i/o.
388 	 * all our completion handlers free their requests in this case.
389 	 */
390 	usb_ep_disable(midi->in_ep);
391 	usb_ep_disable(midi->out_ep);
392 }
393 
394 static int f_midi_snd_free(struct snd_device *device)
395 {
396 	return 0;
397 }
398 
399 static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
400 					uint8_t p1, uint8_t p2, uint8_t p3)
401 {
402 	unsigned length = req->length;
403 	u8 *buf = (u8 *)req->buf + length;
404 
405 	buf[0] = p0;
406 	buf[1] = p1;
407 	buf[2] = p2;
408 	buf[3] = p3;
409 	req->length = length + 4;
410 }
411 
412 /*
413  * Converts MIDI commands to USB MIDI packets.
414  */
415 static void f_midi_transmit_byte(struct usb_request *req,
416 				 struct gmidi_in_port *port, uint8_t b)
417 {
418 	uint8_t p0 = port->cable << 4;
419 
420 	if (b >= 0xf8) {
421 		f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
422 	} else if (b >= 0xf0) {
423 		switch (b) {
424 		case 0xf0:
425 			port->data[0] = b;
426 			port->state = STATE_SYSEX_1;
427 			break;
428 		case 0xf1:
429 		case 0xf3:
430 			port->data[0] = b;
431 			port->state = STATE_1PARAM;
432 			break;
433 		case 0xf2:
434 			port->data[0] = b;
435 			port->state = STATE_2PARAM_1;
436 			break;
437 		case 0xf4:
438 		case 0xf5:
439 			port->state = STATE_UNKNOWN;
440 			break;
441 		case 0xf6:
442 			f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
443 			port->state = STATE_UNKNOWN;
444 			break;
445 		case 0xf7:
446 			switch (port->state) {
447 			case STATE_SYSEX_0:
448 				f_midi_transmit_packet(req,
449 					p0 | 0x05, 0xf7, 0, 0);
450 				break;
451 			case STATE_SYSEX_1:
452 				f_midi_transmit_packet(req,
453 					p0 | 0x06, port->data[0], 0xf7, 0);
454 				break;
455 			case STATE_SYSEX_2:
456 				f_midi_transmit_packet(req,
457 					p0 | 0x07, port->data[0],
458 					port->data[1], 0xf7);
459 				break;
460 			}
461 			port->state = STATE_UNKNOWN;
462 			break;
463 		}
464 	} else if (b >= 0x80) {
465 		port->data[0] = b;
466 		if (b >= 0xc0 && b <= 0xdf)
467 			port->state = STATE_1PARAM;
468 		else
469 			port->state = STATE_2PARAM_1;
470 	} else { /* b < 0x80 */
471 		switch (port->state) {
472 		case STATE_1PARAM:
473 			if (port->data[0] < 0xf0) {
474 				p0 |= port->data[0] >> 4;
475 			} else {
476 				p0 |= 0x02;
477 				port->state = STATE_UNKNOWN;
478 			}
479 			f_midi_transmit_packet(req, p0, port->data[0], b, 0);
480 			break;
481 		case STATE_2PARAM_1:
482 			port->data[1] = b;
483 			port->state = STATE_2PARAM_2;
484 			break;
485 		case STATE_2PARAM_2:
486 			if (port->data[0] < 0xf0) {
487 				p0 |= port->data[0] >> 4;
488 				port->state = STATE_2PARAM_1;
489 			} else {
490 				p0 |= 0x03;
491 				port->state = STATE_UNKNOWN;
492 			}
493 			f_midi_transmit_packet(req,
494 				p0, port->data[0], port->data[1], b);
495 			break;
496 		case STATE_SYSEX_0:
497 			port->data[0] = b;
498 			port->state = STATE_SYSEX_1;
499 			break;
500 		case STATE_SYSEX_1:
501 			port->data[1] = b;
502 			port->state = STATE_SYSEX_2;
503 			break;
504 		case STATE_SYSEX_2:
505 			f_midi_transmit_packet(req,
506 				p0 | 0x04, port->data[0], port->data[1], b);
507 			port->state = STATE_SYSEX_0;
508 			break;
509 		}
510 	}
511 }
512 
513 static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
514 {
515 	struct usb_ep *ep = midi->in_ep;
516 	int i;
517 
518 	if (!ep)
519 		return;
520 
521 	if (!req)
522 		req = midi_alloc_ep_req(ep, midi->buflen);
523 
524 	if (!req) {
525 		ERROR(midi, "%s: alloc_ep_request failed\n", __func__);
526 		return;
527 	}
528 	req->length = 0;
529 	req->complete = f_midi_complete;
530 
531 	for (i = 0; i < MAX_PORTS; i++) {
532 		struct gmidi_in_port *port = midi->in_port[i];
533 		struct snd_rawmidi_substream *substream = midi->in_substream[i];
534 
535 		if (!port || !port->active || !substream)
536 			continue;
537 
538 		while (req->length + 3 < midi->buflen) {
539 			uint8_t b;
540 			if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
541 				port->active = 0;
542 				break;
543 			}
544 			f_midi_transmit_byte(req, port, b);
545 		}
546 	}
547 
548 	if (req->length > 0) {
549 		int err;
550 
551 		err = usb_ep_queue(ep, req, GFP_ATOMIC);
552 		if (err < 0)
553 			ERROR(midi, "%s queue req: %d\n",
554 			      midi->in_ep->name, err);
555 	} else {
556 		free_ep_req(ep, req);
557 	}
558 }
559 
560 static void f_midi_in_tasklet(unsigned long data)
561 {
562 	struct f_midi *midi = (struct f_midi *) data;
563 	f_midi_transmit(midi, NULL);
564 }
565 
566 static int f_midi_in_open(struct snd_rawmidi_substream *substream)
567 {
568 	struct f_midi *midi = substream->rmidi->private_data;
569 
570 	if (!midi->in_port[substream->number])
571 		return -EINVAL;
572 
573 	VDBG(midi, "%s()\n", __func__);
574 	midi->in_substream[substream->number] = substream;
575 	midi->in_port[substream->number]->state = STATE_UNKNOWN;
576 	return 0;
577 }
578 
579 static int f_midi_in_close(struct snd_rawmidi_substream *substream)
580 {
581 	struct f_midi *midi = substream->rmidi->private_data;
582 
583 	VDBG(midi, "%s()\n", __func__);
584 	return 0;
585 }
586 
587 static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
588 {
589 	struct f_midi *midi = substream->rmidi->private_data;
590 
591 	if (!midi->in_port[substream->number])
592 		return;
593 
594 	VDBG(midi, "%s() %d\n", __func__, up);
595 	midi->in_port[substream->number]->active = up;
596 	if (up)
597 		tasklet_hi_schedule(&midi->tasklet);
598 }
599 
600 static int f_midi_out_open(struct snd_rawmidi_substream *substream)
601 {
602 	struct f_midi *midi = substream->rmidi->private_data;
603 
604 	if (substream->number >= MAX_PORTS)
605 		return -EINVAL;
606 
607 	VDBG(midi, "%s()\n", __func__);
608 	midi->out_substream[substream->number] = substream;
609 	return 0;
610 }
611 
612 static int f_midi_out_close(struct snd_rawmidi_substream *substream)
613 {
614 	struct f_midi *midi = substream->rmidi->private_data;
615 
616 	VDBG(midi, "%s()\n", __func__);
617 	return 0;
618 }
619 
620 static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
621 {
622 	struct f_midi *midi = substream->rmidi->private_data;
623 
624 	VDBG(midi, "%s()\n", __func__);
625 
626 	if (up)
627 		set_bit(substream->number, &midi->out_triggered);
628 	else
629 		clear_bit(substream->number, &midi->out_triggered);
630 }
631 
632 static struct snd_rawmidi_ops gmidi_in_ops = {
633 	.open = f_midi_in_open,
634 	.close = f_midi_in_close,
635 	.trigger = f_midi_in_trigger,
636 };
637 
638 static struct snd_rawmidi_ops gmidi_out_ops = {
639 	.open = f_midi_out_open,
640 	.close = f_midi_out_close,
641 	.trigger = f_midi_out_trigger
642 };
643 
644 static inline void f_midi_unregister_card(struct f_midi *midi)
645 {
646 	if (midi->card) {
647 		snd_card_free(midi->card);
648 		midi->card = NULL;
649 	}
650 }
651 
652 /* register as a sound "card" */
653 static int f_midi_register_card(struct f_midi *midi)
654 {
655 	struct snd_card *card;
656 	struct snd_rawmidi *rmidi;
657 	int err;
658 	static struct snd_device_ops ops = {
659 		.dev_free = f_midi_snd_free,
660 	};
661 
662 	err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
663 			   THIS_MODULE, 0, &card);
664 	if (err < 0) {
665 		ERROR(midi, "snd_card_new() failed\n");
666 		goto fail;
667 	}
668 	midi->card = card;
669 
670 	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
671 	if (err < 0) {
672 		ERROR(midi, "snd_device_new() failed: error %d\n", err);
673 		goto fail;
674 	}
675 
676 	strcpy(card->driver, f_midi_longname);
677 	strcpy(card->longname, f_midi_longname);
678 	strcpy(card->shortname, f_midi_shortname);
679 
680 	/* Set up rawmidi */
681 	snd_component_add(card, "MIDI");
682 	err = snd_rawmidi_new(card, card->longname, 0,
683 			      midi->out_ports, midi->in_ports, &rmidi);
684 	if (err < 0) {
685 		ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
686 		goto fail;
687 	}
688 	midi->rmidi = rmidi;
689 	strcpy(rmidi->name, card->shortname);
690 	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
691 			    SNDRV_RAWMIDI_INFO_INPUT |
692 			    SNDRV_RAWMIDI_INFO_DUPLEX;
693 	rmidi->private_data = midi;
694 
695 	/*
696 	 * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
697 	 * It's an upside-down world being a gadget.
698 	 */
699 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
700 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
701 
702 	/* register it - we're ready to go */
703 	err = snd_card_register(card);
704 	if (err < 0) {
705 		ERROR(midi, "snd_card_register() failed\n");
706 		goto fail;
707 	}
708 
709 	VDBG(midi, "%s() finished ok\n", __func__);
710 	return 0;
711 
712 fail:
713 	f_midi_unregister_card(midi);
714 	return err;
715 }
716 
717 /* MIDI function driver setup/binding */
718 
719 static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
720 {
721 	struct usb_descriptor_header **midi_function;
722 	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
723 	struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
724 	struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
725 	struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
726 	struct usb_composite_dev *cdev = c->cdev;
727 	struct f_midi *midi = func_to_midi(f);
728 	struct usb_string *us;
729 	int status, n, jack = 1, i = 0;
730 
731 	midi->gadget = cdev->gadget;
732 	tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
733 	status = f_midi_register_card(midi);
734 	if (status < 0)
735 		goto fail_register;
736 
737 	/* maybe allocate device-global string ID */
738 	us = usb_gstrings_attach(c->cdev, midi_strings,
739 				 ARRAY_SIZE(midi_string_defs));
740 	if (IS_ERR(us)) {
741 		status = PTR_ERR(us);
742 		goto fail;
743 	}
744 	ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
745 
746 	/* We have two interfaces, AudioControl and MIDIStreaming */
747 	status = usb_interface_id(c, f);
748 	if (status < 0)
749 		goto fail;
750 	ac_interface_desc.bInterfaceNumber = status;
751 
752 	status = usb_interface_id(c, f);
753 	if (status < 0)
754 		goto fail;
755 	ms_interface_desc.bInterfaceNumber = status;
756 	ac_header_desc.baInterfaceNr[0] = status;
757 
758 	status = -ENODEV;
759 
760 	/* allocate instance-specific endpoints */
761 	midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
762 	if (!midi->in_ep)
763 		goto fail;
764 
765 	midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
766 	if (!midi->out_ep)
767 		goto fail;
768 
769 	/* allocate temporary function list */
770 	midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(*midi_function),
771 				GFP_KERNEL);
772 	if (!midi_function) {
773 		status = -ENOMEM;
774 		goto fail;
775 	}
776 
777 	/*
778 	 * construct the function's descriptor set. As the number of
779 	 * input and output MIDI ports is configurable, we have to do
780 	 * it that way.
781 	 */
782 
783 	/* add the headers - these are always the same */
784 	midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
785 	midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
786 	midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
787 
788 	/* calculate the header's wTotalLength */
789 	n = USB_DT_MS_HEADER_SIZE
790 		+ (midi->in_ports + midi->out_ports) *
791 			(USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
792 	ms_header_desc.wTotalLength = cpu_to_le16(n);
793 
794 	midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
795 
796 	/* configure the external IN jacks, each linked to an embedded OUT jack */
797 	for (n = 0; n < midi->in_ports; n++) {
798 		struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
799 		struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
800 
801 		in_ext->bLength			= USB_DT_MIDI_IN_SIZE;
802 		in_ext->bDescriptorType		= USB_DT_CS_INTERFACE;
803 		in_ext->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
804 		in_ext->bJackType		= USB_MS_EXTERNAL;
805 		in_ext->bJackID			= jack++;
806 		in_ext->iJack			= 0;
807 		midi_function[i++] = (struct usb_descriptor_header *) in_ext;
808 
809 		out_emb->bLength		= USB_DT_MIDI_OUT_SIZE(1);
810 		out_emb->bDescriptorType	= USB_DT_CS_INTERFACE;
811 		out_emb->bDescriptorSubtype	= USB_MS_MIDI_OUT_JACK;
812 		out_emb->bJackType		= USB_MS_EMBEDDED;
813 		out_emb->bJackID		= jack++;
814 		out_emb->bNrInputPins		= 1;
815 		out_emb->pins[0].baSourcePin	= 1;
816 		out_emb->pins[0].baSourceID	= in_ext->bJackID;
817 		out_emb->iJack			= 0;
818 		midi_function[i++] = (struct usb_descriptor_header *) out_emb;
819 
820 		/* link it to the endpoint */
821 		ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
822 	}
823 
824 	/* configure the external OUT jacks, each linked to an embedded IN jack */
825 	for (n = 0; n < midi->out_ports; n++) {
826 		struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
827 		struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
828 
829 		in_emb->bLength			= USB_DT_MIDI_IN_SIZE;
830 		in_emb->bDescriptorType		= USB_DT_CS_INTERFACE;
831 		in_emb->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
832 		in_emb->bJackType		= USB_MS_EMBEDDED;
833 		in_emb->bJackID			= jack++;
834 		in_emb->iJack			= 0;
835 		midi_function[i++] = (struct usb_descriptor_header *) in_emb;
836 
837 		out_ext->bLength =		USB_DT_MIDI_OUT_SIZE(1);
838 		out_ext->bDescriptorType =	USB_DT_CS_INTERFACE;
839 		out_ext->bDescriptorSubtype =	USB_MS_MIDI_OUT_JACK;
840 		out_ext->bJackType =		USB_MS_EXTERNAL;
841 		out_ext->bJackID =		jack++;
842 		out_ext->bNrInputPins =		1;
843 		out_ext->iJack =		0;
844 		out_ext->pins[0].baSourceID =	in_emb->bJackID;
845 		out_ext->pins[0].baSourcePin =	1;
846 		midi_function[i++] = (struct usb_descriptor_header *) out_ext;
847 
848 		/* link it to the endpoint */
849 		ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
850 	}
851 
852 	/* configure the endpoint descriptors ... */
853 	ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
854 	ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
855 
856 	ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
857 	ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
858 
859 	/* ... and add them to the list */
860 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
861 	midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
862 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
863 	midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
864 	midi_function[i++] = NULL;
865 
866 	/*
867 	 * support all relevant hardware speeds... we expect that when
868 	 * hardware is dual speed, all bulk-capable endpoints work at
869 	 * both speeds
870 	 */
871 	/* copy descriptors, and track endpoint copies */
872 	f->fs_descriptors = usb_copy_descriptors(midi_function);
873 	if (!f->fs_descriptors)
874 		goto fail_f_midi;
875 
876 	if (gadget_is_dualspeed(c->cdev->gadget)) {
877 		bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
878 		bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
879 		f->hs_descriptors = usb_copy_descriptors(midi_function);
880 		if (!f->hs_descriptors)
881 			goto fail_f_midi;
882 	}
883 
884 	kfree(midi_function);
885 
886 	return 0;
887 
888 fail_f_midi:
889 	kfree(midi_function);
890 	usb_free_descriptors(f->hs_descriptors);
891 fail:
892 	f_midi_unregister_card(midi);
893 fail_register:
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 static void midi_attr_release(struct config_item *item)
906 {
907 	struct f_midi_opts *opts = to_f_midi_opts(item);
908 
909 	usb_put_function_instance(&opts->func_inst);
910 }
911 
912 static struct configfs_item_operations midi_item_ops = {
913 	.release	= midi_attr_release,
914 };
915 
916 #define F_MIDI_OPT(name, test_limit, limit)				\
917 static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
918 {									\
919 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
920 	int result;							\
921 									\
922 	mutex_lock(&opts->lock);					\
923 	result = sprintf(page, "%d\n", opts->name);			\
924 	mutex_unlock(&opts->lock);					\
925 									\
926 	return result;							\
927 }									\
928 									\
929 static ssize_t f_midi_opts_##name##_store(struct config_item *item,	\
930 					 const char *page, size_t len)	\
931 {									\
932 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
933 	int ret;							\
934 	u32 num;							\
935 									\
936 	mutex_lock(&opts->lock);					\
937 	if (opts->refcnt) {						\
938 		ret = -EBUSY;						\
939 		goto end;						\
940 	}								\
941 									\
942 	ret = kstrtou32(page, 0, &num);					\
943 	if (ret)							\
944 		goto end;						\
945 									\
946 	if (test_limit && num > limit) {				\
947 		ret = -EINVAL;						\
948 		goto end;						\
949 	}								\
950 	opts->name = num;						\
951 	ret = len;							\
952 									\
953 end:									\
954 	mutex_unlock(&opts->lock);					\
955 	return ret;							\
956 }									\
957 									\
958 CONFIGFS_ATTR(f_midi_opts_, name);
959 
960 F_MIDI_OPT(index, true, SNDRV_CARDS);
961 F_MIDI_OPT(buflen, false, 0);
962 F_MIDI_OPT(qlen, false, 0);
963 F_MIDI_OPT(in_ports, true, MAX_PORTS);
964 F_MIDI_OPT(out_ports, true, MAX_PORTS);
965 
966 static ssize_t f_midi_opts_id_show(struct config_item *item, char *page)
967 {
968 	struct f_midi_opts *opts = to_f_midi_opts(item);
969 	int result;
970 
971 	mutex_lock(&opts->lock);
972 	if (opts->id) {
973 		result = strlcpy(page, opts->id, PAGE_SIZE);
974 	} else {
975 		page[0] = 0;
976 		result = 0;
977 	}
978 
979 	mutex_unlock(&opts->lock);
980 
981 	return result;
982 }
983 
984 static ssize_t f_midi_opts_id_store(struct config_item *item,
985 				    const char *page, size_t len)
986 {
987 	struct f_midi_opts *opts = to_f_midi_opts(item);
988 	int ret;
989 	char *c;
990 
991 	mutex_lock(&opts->lock);
992 	if (opts->refcnt) {
993 		ret = -EBUSY;
994 		goto end;
995 	}
996 
997 	c = kstrndup(page, len, GFP_KERNEL);
998 	if (!c) {
999 		ret = -ENOMEM;
1000 		goto end;
1001 	}
1002 	if (opts->id_allocated)
1003 		kfree(opts->id);
1004 	opts->id = c;
1005 	opts->id_allocated = true;
1006 	ret = len;
1007 end:
1008 	mutex_unlock(&opts->lock);
1009 	return ret;
1010 }
1011 
1012 CONFIGFS_ATTR(f_midi_opts_, id);
1013 
1014 static struct configfs_attribute *midi_attrs[] = {
1015 	&f_midi_opts_attr_index,
1016 	&f_midi_opts_attr_buflen,
1017 	&f_midi_opts_attr_qlen,
1018 	&f_midi_opts_attr_in_ports,
1019 	&f_midi_opts_attr_out_ports,
1020 	&f_midi_opts_attr_id,
1021 	NULL,
1022 };
1023 
1024 static struct config_item_type midi_func_type = {
1025 	.ct_item_ops	= &midi_item_ops,
1026 	.ct_attrs	= midi_attrs,
1027 	.ct_owner	= THIS_MODULE,
1028 };
1029 
1030 static void f_midi_free_inst(struct usb_function_instance *f)
1031 {
1032 	struct f_midi_opts *opts;
1033 
1034 	opts = container_of(f, struct f_midi_opts, func_inst);
1035 
1036 	if (opts->id_allocated)
1037 		kfree(opts->id);
1038 
1039 	kfree(opts);
1040 }
1041 
1042 static struct usb_function_instance *f_midi_alloc_inst(void)
1043 {
1044 	struct f_midi_opts *opts;
1045 
1046 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1047 	if (!opts)
1048 		return ERR_PTR(-ENOMEM);
1049 
1050 	mutex_init(&opts->lock);
1051 	opts->func_inst.free_func_inst = f_midi_free_inst;
1052 	opts->index = SNDRV_DEFAULT_IDX1;
1053 	opts->id = SNDRV_DEFAULT_STR1;
1054 	opts->buflen = 256;
1055 	opts->qlen = 32;
1056 	opts->in_ports = 1;
1057 	opts->out_ports = 1;
1058 
1059 	config_group_init_type_name(&opts->func_inst.group, "",
1060 				    &midi_func_type);
1061 
1062 	return &opts->func_inst;
1063 }
1064 
1065 static void f_midi_free(struct usb_function *f)
1066 {
1067 	struct f_midi *midi;
1068 	struct f_midi_opts *opts;
1069 	int i;
1070 
1071 	midi = func_to_midi(f);
1072 	opts = container_of(f->fi, struct f_midi_opts, func_inst);
1073 	kfree(midi->id);
1074 	mutex_lock(&opts->lock);
1075 	for (i = opts->in_ports - 1; i >= 0; --i)
1076 		kfree(midi->in_port[i]);
1077 	kfree(midi);
1078 	--opts->refcnt;
1079 	mutex_unlock(&opts->lock);
1080 }
1081 
1082 static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
1083 {
1084 	struct usb_composite_dev *cdev = f->config->cdev;
1085 	struct f_midi *midi = func_to_midi(f);
1086 	struct snd_card *card;
1087 
1088 	DBG(cdev, "unbind\n");
1089 
1090 	/* just to be sure */
1091 	f_midi_disable(f);
1092 
1093 	card = midi->card;
1094 	midi->card = NULL;
1095 	if (card)
1096 		snd_card_free(card);
1097 
1098 	usb_free_all_descriptors(f);
1099 }
1100 
1101 static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
1102 {
1103 	struct f_midi *midi;
1104 	struct f_midi_opts *opts;
1105 	int status, i;
1106 
1107 	opts = container_of(fi, struct f_midi_opts, func_inst);
1108 
1109 	mutex_lock(&opts->lock);
1110 	/* sanity check */
1111 	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
1112 		mutex_unlock(&opts->lock);
1113 		return ERR_PTR(-EINVAL);
1114 	}
1115 
1116 	/* allocate and initialize one new instance */
1117 	midi = kzalloc(sizeof(*midi), GFP_KERNEL);
1118 	if (!midi) {
1119 		mutex_unlock(&opts->lock);
1120 		return ERR_PTR(-ENOMEM);
1121 	}
1122 
1123 	for (i = 0; i < opts->in_ports; i++) {
1124 		struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
1125 
1126 		if (!port) {
1127 			status = -ENOMEM;
1128 			mutex_unlock(&opts->lock);
1129 			goto setup_fail;
1130 		}
1131 
1132 		port->midi = midi;
1133 		port->active = 0;
1134 		port->cable = i;
1135 		midi->in_port[i] = port;
1136 	}
1137 
1138 	/* set up ALSA midi devices */
1139 	midi->id = kstrdup(opts->id, GFP_KERNEL);
1140 	if (opts->id && !midi->id) {
1141 		status = -ENOMEM;
1142 		mutex_unlock(&opts->lock);
1143 		goto setup_fail;
1144 	}
1145 	midi->in_ports = opts->in_ports;
1146 	midi->out_ports = opts->out_ports;
1147 	midi->index = opts->index;
1148 	midi->buflen = opts->buflen;
1149 	midi->qlen = opts->qlen;
1150 	++opts->refcnt;
1151 	mutex_unlock(&opts->lock);
1152 
1153 	midi->func.name		= "gmidi function";
1154 	midi->func.bind		= f_midi_bind;
1155 	midi->func.unbind	= f_midi_unbind;
1156 	midi->func.set_alt	= f_midi_set_alt;
1157 	midi->func.disable	= f_midi_disable;
1158 	midi->func.free_func	= f_midi_free;
1159 
1160 	return &midi->func;
1161 
1162 setup_fail:
1163 	for (--i; i >= 0; i--)
1164 		kfree(midi->in_port[i]);
1165 	kfree(midi);
1166 	return ERR_PTR(status);
1167 }
1168 
1169 DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);
1170