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 #include <linux/kfifo.h>
27 
28 #include <sound/core.h>
29 #include <sound/initval.h>
30 #include <sound/rawmidi.h>
31 
32 #include <linux/usb/ch9.h>
33 #include <linux/usb/gadget.h>
34 #include <linux/usb/audio.h>
35 #include <linux/usb/midi.h>
36 
37 #include "u_f.h"
38 #include "u_midi.h"
39 
40 MODULE_AUTHOR("Ben Williamson");
41 MODULE_LICENSE("GPL v2");
42 
43 static const char f_midi_shortname[] = "f_midi";
44 static const char f_midi_longname[] = "MIDI Gadget";
45 
46 /*
47  * We can only handle 16 cables on one single endpoint, as cable numbers are
48  * stored in 4-bit fields. And as the interface currently only holds one
49  * single endpoint, this is the maximum number of ports we can allow.
50  */
51 #define MAX_PORTS 16
52 
53 /*
54  * This is a gadget, and the IN/OUT naming is from the host's perspective.
55  * USB -> OUT endpoint -> rawmidi
56  * USB <- IN endpoint  <- rawmidi
57  */
58 struct gmidi_in_port {
59 	struct f_midi *midi;
60 	int active;
61 	uint8_t cable;
62 	uint8_t state;
63 #define STATE_UNKNOWN	0
64 #define STATE_1PARAM	1
65 #define STATE_2PARAM_1	2
66 #define STATE_2PARAM_2	3
67 #define STATE_SYSEX_0	4
68 #define STATE_SYSEX_1	5
69 #define STATE_SYSEX_2	6
70 	uint8_t data[2];
71 };
72 
73 struct f_midi {
74 	struct usb_function	func;
75 	struct usb_gadget	*gadget;
76 	struct usb_ep		*in_ep, *out_ep;
77 	struct snd_card		*card;
78 	struct snd_rawmidi	*rmidi;
79 	u8			ms_id;
80 
81 	struct snd_rawmidi_substream *in_substream[MAX_PORTS];
82 	struct snd_rawmidi_substream *out_substream[MAX_PORTS];
83 	struct gmidi_in_port	*in_port[MAX_PORTS];
84 
85 	unsigned long		out_triggered;
86 	struct tasklet_struct	tasklet;
87 	unsigned int in_ports;
88 	unsigned int out_ports;
89 	int index;
90 	char *id;
91 	unsigned int buflen, qlen;
92 	/* This fifo is used as a buffer ring for pre-allocated IN usb_requests */
93 	DECLARE_KFIFO_PTR(in_req_fifo, struct usb_request *);
94 	unsigned int in_last_port;
95 };
96 
97 static inline struct f_midi *func_to_midi(struct usb_function *f)
98 {
99 	return container_of(f, struct f_midi, func);
100 }
101 
102 static void f_midi_transmit(struct f_midi *midi);
103 
104 DECLARE_UAC_AC_HEADER_DESCRIPTOR(1);
105 DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1);
106 DECLARE_USB_MS_ENDPOINT_DESCRIPTOR(16);
107 
108 /* B.3.1  Standard AC Interface Descriptor */
109 static struct usb_interface_descriptor ac_interface_desc = {
110 	.bLength =		USB_DT_INTERFACE_SIZE,
111 	.bDescriptorType =	USB_DT_INTERFACE,
112 	/* .bInterfaceNumber =	DYNAMIC */
113 	/* .bNumEndpoints =	DYNAMIC */
114 	.bInterfaceClass =	USB_CLASS_AUDIO,
115 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
116 	/* .iInterface =	DYNAMIC */
117 };
118 
119 /* B.3.2  Class-Specific AC Interface Descriptor */
120 static struct uac1_ac_header_descriptor_1 ac_header_desc = {
121 	.bLength =		UAC_DT_AC_HEADER_SIZE(1),
122 	.bDescriptorType =	USB_DT_CS_INTERFACE,
123 	.bDescriptorSubtype =	USB_MS_HEADER,
124 	.bcdADC =		cpu_to_le16(0x0100),
125 	.wTotalLength =		cpu_to_le16(UAC_DT_AC_HEADER_SIZE(1)),
126 	.bInCollection =	1,
127 	/* .baInterfaceNr =	DYNAMIC */
128 };
129 
130 /* B.4.1  Standard MS Interface Descriptor */
131 static struct usb_interface_descriptor ms_interface_desc = {
132 	.bLength =		USB_DT_INTERFACE_SIZE,
133 	.bDescriptorType =	USB_DT_INTERFACE,
134 	/* .bInterfaceNumber =	DYNAMIC */
135 	.bNumEndpoints =	2,
136 	.bInterfaceClass =	USB_CLASS_AUDIO,
137 	.bInterfaceSubClass =	USB_SUBCLASS_MIDISTREAMING,
138 	/* .iInterface =	DYNAMIC */
139 };
140 
141 /* B.4.2  Class-Specific MS Interface Descriptor */
142 static struct usb_ms_header_descriptor ms_header_desc = {
143 	.bLength =		USB_DT_MS_HEADER_SIZE,
144 	.bDescriptorType =	USB_DT_CS_INTERFACE,
145 	.bDescriptorSubtype =	USB_MS_HEADER,
146 	.bcdMSC =		cpu_to_le16(0x0100),
147 	/* .wTotalLength =	DYNAMIC */
148 };
149 
150 /* B.5.1  Standard Bulk OUT Endpoint Descriptor */
151 static struct usb_endpoint_descriptor bulk_out_desc = {
152 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
153 	.bDescriptorType =	USB_DT_ENDPOINT,
154 	.bEndpointAddress =	USB_DIR_OUT,
155 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
156 };
157 
158 /* B.5.2  Class-specific MS Bulk OUT Endpoint Descriptor */
159 static struct usb_ms_endpoint_descriptor_16 ms_out_desc = {
160 	/* .bLength =		DYNAMIC */
161 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
162 	.bDescriptorSubtype =	USB_MS_GENERAL,
163 	/* .bNumEmbMIDIJack =	DYNAMIC */
164 	/* .baAssocJackID =	DYNAMIC */
165 };
166 
167 /* B.6.1  Standard Bulk IN Endpoint Descriptor */
168 static struct usb_endpoint_descriptor bulk_in_desc = {
169 	.bLength =		USB_DT_ENDPOINT_AUDIO_SIZE,
170 	.bDescriptorType =	USB_DT_ENDPOINT,
171 	.bEndpointAddress =	USB_DIR_IN,
172 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
173 };
174 
175 /* B.6.2  Class-specific MS Bulk IN Endpoint Descriptor */
176 static struct usb_ms_endpoint_descriptor_16 ms_in_desc = {
177 	/* .bLength =		DYNAMIC */
178 	.bDescriptorType =	USB_DT_CS_ENDPOINT,
179 	.bDescriptorSubtype =	USB_MS_GENERAL,
180 	/* .bNumEmbMIDIJack =	DYNAMIC */
181 	/* .baAssocJackID =	DYNAMIC */
182 };
183 
184 /* string IDs are assigned dynamically */
185 
186 #define STRING_FUNC_IDX			0
187 
188 static struct usb_string midi_string_defs[] = {
189 	[STRING_FUNC_IDX].s = "MIDI function",
190 	{  } /* end of list */
191 };
192 
193 static struct usb_gadget_strings midi_stringtab = {
194 	.language	= 0x0409,	/* en-us */
195 	.strings	= midi_string_defs,
196 };
197 
198 static struct usb_gadget_strings *midi_strings[] = {
199 	&midi_stringtab,
200 	NULL,
201 };
202 
203 static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
204 						    unsigned length)
205 {
206 	return alloc_ep_req(ep, length, length);
207 }
208 
209 static const uint8_t f_midi_cin_length[] = {
210 	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
211 };
212 
213 /*
214  * Receives a chunk of MIDI data.
215  */
216 static void f_midi_read_data(struct usb_ep *ep, int cable,
217 			     uint8_t *data, int length)
218 {
219 	struct f_midi *midi = ep->driver_data;
220 	struct snd_rawmidi_substream *substream = midi->out_substream[cable];
221 
222 	if (!substream)
223 		/* Nobody is listening - throw it on the floor. */
224 		return;
225 
226 	if (!test_bit(cable, &midi->out_triggered))
227 		return;
228 
229 	snd_rawmidi_receive(substream, data, length);
230 }
231 
232 static void f_midi_handle_out_data(struct usb_ep *ep, struct usb_request *req)
233 {
234 	unsigned int i;
235 	u8 *buf = req->buf;
236 
237 	for (i = 0; i + 3 < req->actual; i += 4)
238 		if (buf[i] != 0) {
239 			int cable = buf[i] >> 4;
240 			int length = f_midi_cin_length[buf[i] & 0x0f];
241 			f_midi_read_data(ep, cable, &buf[i + 1], length);
242 		}
243 }
244 
245 static void
246 f_midi_complete(struct usb_ep *ep, struct usb_request *req)
247 {
248 	struct f_midi *midi = ep->driver_data;
249 	struct usb_composite_dev *cdev = midi->func.config->cdev;
250 	int status = req->status;
251 
252 	switch (status) {
253 	case 0:			 /* normal completion */
254 		if (ep == midi->out_ep) {
255 			/* We received stuff. req is queued again, below */
256 			f_midi_handle_out_data(ep, req);
257 		} else if (ep == midi->in_ep) {
258 			/* Our transmit completed. See if there's more to go.
259 			 * f_midi_transmit eats req, don't queue it again. */
260 			req->length = 0;
261 			f_midi_transmit(midi);
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 			/* We don't need to free IN requests because it's handled
275 			 * by the midi->in_req_fifo. */
276 			free_ep_req(ep, req);
277 		}
278 		return;
279 
280 	case -EOVERFLOW:	/* buffer overrun on read means that
281 				 * we didn't provide a big enough buffer.
282 				 */
283 	default:
284 		DBG(cdev, "%s complete --> %d, %d/%d\n", ep->name,
285 				status, req->actual, req->length);
286 		break;
287 	case -EREMOTEIO:	/* short read */
288 		break;
289 	}
290 
291 	status = usb_ep_queue(ep, req, GFP_ATOMIC);
292 	if (status) {
293 		ERROR(cdev, "kill %s:  resubmit %d bytes --> %d\n",
294 				ep->name, req->length, status);
295 		usb_ep_set_halt(ep);
296 		/* FIXME recover later ... somehow */
297 	}
298 }
299 
300 static int f_midi_start_ep(struct f_midi *midi,
301 			   struct usb_function *f,
302 			   struct usb_ep *ep)
303 {
304 	int err;
305 	struct usb_composite_dev *cdev = f->config->cdev;
306 
307 	usb_ep_disable(ep);
308 
309 	err = config_ep_by_speed(midi->gadget, f, ep);
310 	if (err) {
311 		ERROR(cdev, "can't configure %s: %d\n", ep->name, err);
312 		return err;
313 	}
314 
315 	err = usb_ep_enable(ep);
316 	if (err) {
317 		ERROR(cdev, "can't start %s: %d\n", ep->name, err);
318 		return err;
319 	}
320 
321 	ep->driver_data = midi;
322 
323 	return 0;
324 }
325 
326 static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
327 {
328 	struct f_midi *midi = func_to_midi(f);
329 	unsigned i;
330 	int err;
331 
332 	/* we only set alt for MIDIStreaming interface */
333 	if (intf != midi->ms_id)
334 		return 0;
335 
336 	err = f_midi_start_ep(midi, f, midi->in_ep);
337 	if (err)
338 		return err;
339 
340 	err = f_midi_start_ep(midi, f, midi->out_ep);
341 	if (err)
342 		return err;
343 
344 	/* pre-allocate write usb requests to use on f_midi_transmit. */
345 	while (kfifo_avail(&midi->in_req_fifo)) {
346 		struct usb_request *req =
347 			midi_alloc_ep_req(midi->in_ep, midi->buflen);
348 
349 		if (req == NULL)
350 			return -ENOMEM;
351 
352 		req->length = 0;
353 		req->complete = f_midi_complete;
354 
355 		kfifo_put(&midi->in_req_fifo, req);
356 	}
357 
358 	/* allocate a bunch of read buffers and queue them all at once. */
359 	for (i = 0; i < midi->qlen && err == 0; i++) {
360 		struct usb_request *req =
361 			midi_alloc_ep_req(midi->out_ep, midi->buflen);
362 		if (req == NULL)
363 			return -ENOMEM;
364 
365 		req->complete = f_midi_complete;
366 		err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
367 		if (err) {
368 			ERROR(midi, "%s: couldn't enqueue request: %d\n",
369 				    midi->out_ep->name, err);
370 			free_ep_req(midi->out_ep, req);
371 			return err;
372 		}
373 	}
374 
375 	return 0;
376 }
377 
378 static void f_midi_disable(struct usb_function *f)
379 {
380 	struct f_midi *midi = func_to_midi(f);
381 	struct usb_composite_dev *cdev = f->config->cdev;
382 	struct usb_request *req = NULL;
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 	/* release IN requests */
394 	while (kfifo_get(&midi->in_req_fifo, &req))
395 		free_ep_req(midi->in_ep, req);
396 }
397 
398 static int f_midi_snd_free(struct snd_device *device)
399 {
400 	return 0;
401 }
402 
403 static void f_midi_transmit_packet(struct usb_request *req, uint8_t p0,
404 					uint8_t p1, uint8_t p2, uint8_t p3)
405 {
406 	unsigned length = req->length;
407 	u8 *buf = (u8 *)req->buf + length;
408 
409 	buf[0] = p0;
410 	buf[1] = p1;
411 	buf[2] = p2;
412 	buf[3] = p3;
413 	req->length = length + 4;
414 }
415 
416 /*
417  * Converts MIDI commands to USB MIDI packets.
418  */
419 static void f_midi_transmit_byte(struct usb_request *req,
420 				 struct gmidi_in_port *port, uint8_t b)
421 {
422 	uint8_t p0 = port->cable << 4;
423 
424 	if (b >= 0xf8) {
425 		f_midi_transmit_packet(req, p0 | 0x0f, b, 0, 0);
426 	} else if (b >= 0xf0) {
427 		switch (b) {
428 		case 0xf0:
429 			port->data[0] = b;
430 			port->state = STATE_SYSEX_1;
431 			break;
432 		case 0xf1:
433 		case 0xf3:
434 			port->data[0] = b;
435 			port->state = STATE_1PARAM;
436 			break;
437 		case 0xf2:
438 			port->data[0] = b;
439 			port->state = STATE_2PARAM_1;
440 			break;
441 		case 0xf4:
442 		case 0xf5:
443 			port->state = STATE_UNKNOWN;
444 			break;
445 		case 0xf6:
446 			f_midi_transmit_packet(req, p0 | 0x05, 0xf6, 0, 0);
447 			port->state = STATE_UNKNOWN;
448 			break;
449 		case 0xf7:
450 			switch (port->state) {
451 			case STATE_SYSEX_0:
452 				f_midi_transmit_packet(req,
453 					p0 | 0x05, 0xf7, 0, 0);
454 				break;
455 			case STATE_SYSEX_1:
456 				f_midi_transmit_packet(req,
457 					p0 | 0x06, port->data[0], 0xf7, 0);
458 				break;
459 			case STATE_SYSEX_2:
460 				f_midi_transmit_packet(req,
461 					p0 | 0x07, port->data[0],
462 					port->data[1], 0xf7);
463 				break;
464 			}
465 			port->state = STATE_UNKNOWN;
466 			break;
467 		}
468 	} else if (b >= 0x80) {
469 		port->data[0] = b;
470 		if (b >= 0xc0 && b <= 0xdf)
471 			port->state = STATE_1PARAM;
472 		else
473 			port->state = STATE_2PARAM_1;
474 	} else { /* b < 0x80 */
475 		switch (port->state) {
476 		case STATE_1PARAM:
477 			if (port->data[0] < 0xf0) {
478 				p0 |= port->data[0] >> 4;
479 			} else {
480 				p0 |= 0x02;
481 				port->state = STATE_UNKNOWN;
482 			}
483 			f_midi_transmit_packet(req, p0, port->data[0], b, 0);
484 			break;
485 		case STATE_2PARAM_1:
486 			port->data[1] = b;
487 			port->state = STATE_2PARAM_2;
488 			break;
489 		case STATE_2PARAM_2:
490 			if (port->data[0] < 0xf0) {
491 				p0 |= port->data[0] >> 4;
492 				port->state = STATE_2PARAM_1;
493 			} else {
494 				p0 |= 0x03;
495 				port->state = STATE_UNKNOWN;
496 			}
497 			f_midi_transmit_packet(req,
498 				p0, port->data[0], port->data[1], b);
499 			break;
500 		case STATE_SYSEX_0:
501 			port->data[0] = b;
502 			port->state = STATE_SYSEX_1;
503 			break;
504 		case STATE_SYSEX_1:
505 			port->data[1] = b;
506 			port->state = STATE_SYSEX_2;
507 			break;
508 		case STATE_SYSEX_2:
509 			f_midi_transmit_packet(req,
510 				p0 | 0x04, port->data[0], port->data[1], b);
511 			port->state = STATE_SYSEX_0;
512 			break;
513 		}
514 	}
515 }
516 
517 static void f_midi_drop_out_substreams(struct f_midi *midi)
518 {
519 	unsigned int i;
520 
521 	for (i = 0; i < MAX_PORTS; i++) {
522 		struct gmidi_in_port *port = midi->in_port[i];
523 		struct snd_rawmidi_substream *substream = midi->in_substream[i];
524 
525 		if (!port)
526 			break;
527 
528 		if (!port->active || !substream)
529 			continue;
530 
531 		snd_rawmidi_drop_output(substream);
532 	}
533 }
534 
535 static void f_midi_transmit(struct f_midi *midi)
536 {
537 	struct usb_ep *ep = midi->in_ep;
538 	bool active;
539 
540 	/* We only care about USB requests if IN endpoint is enabled */
541 	if (!ep || !ep->enabled)
542 		goto drop_out;
543 
544 	do {
545 		struct usb_request *req = NULL;
546 		unsigned int len, i;
547 
548 		active = false;
549 
550 		/* We peek the request in order to reuse it if it fails
551 		 * to enqueue on its endpoint */
552 		len = kfifo_peek(&midi->in_req_fifo, &req);
553 		if (len != 1) {
554 			ERROR(midi, "%s: Couldn't get usb request\n", __func__);
555 			goto drop_out;
556 		}
557 
558 		/* If buffer overrun, then we ignore this transmission.
559 		 * IMPORTANT: This will cause the user-space rawmidi device to block until a) usb
560 		 * requests have been completed or b) snd_rawmidi_write() times out. */
561 		if (req->length > 0)
562 			return;
563 
564 		for (i = midi->in_last_port; i < MAX_PORTS; i++) {
565 			struct gmidi_in_port *port = midi->in_port[i];
566 			struct snd_rawmidi_substream *substream = midi->in_substream[i];
567 
568 			if (!port) {
569 				/* Reset counter when we reach the last available port */
570 				midi->in_last_port = 0;
571 				break;
572 			}
573 
574 			if (!port->active || !substream)
575 				continue;
576 
577 			while (req->length + 3 < midi->buflen) {
578 				uint8_t b;
579 
580 				if (snd_rawmidi_transmit(substream, &b, 1) != 1) {
581 					port->active = 0;
582 					break;
583 				}
584 				f_midi_transmit_byte(req, port, b);
585 			}
586 
587 			active = !!port->active;
588 			/* Check if last port is still active, which means that
589 			 * there is still data on that substream but this current
590 			 * request run out of space. */
591 			if (active) {
592 				midi->in_last_port = i;
593 				/* There is no need to re-iterate though midi ports. */
594 				break;
595 			}
596 		}
597 
598 		if (req->length > 0) {
599 			int err;
600 
601 			err = usb_ep_queue(ep, req, GFP_ATOMIC);
602 			if (err < 0) {
603 				ERROR(midi, "%s failed to queue req: %d\n",
604 				      midi->in_ep->name, err);
605 				req->length = 0; /* Re-use request next time. */
606 			} else {
607 				/* Upon success, put request at the back of the queue. */
608 				kfifo_skip(&midi->in_req_fifo);
609 				kfifo_put(&midi->in_req_fifo, req);
610 			}
611 		}
612 	} while (active);
613 
614 	return;
615 
616 drop_out:
617 	f_midi_drop_out_substreams(midi);
618 }
619 
620 static void f_midi_in_tasklet(unsigned long data)
621 {
622 	struct f_midi *midi = (struct f_midi *) data;
623 	f_midi_transmit(midi);
624 }
625 
626 static int f_midi_in_open(struct snd_rawmidi_substream *substream)
627 {
628 	struct f_midi *midi = substream->rmidi->private_data;
629 
630 	if (!midi->in_port[substream->number])
631 		return -EINVAL;
632 
633 	VDBG(midi, "%s()\n", __func__);
634 	midi->in_substream[substream->number] = substream;
635 	midi->in_port[substream->number]->state = STATE_UNKNOWN;
636 	return 0;
637 }
638 
639 static int f_midi_in_close(struct snd_rawmidi_substream *substream)
640 {
641 	struct f_midi *midi = substream->rmidi->private_data;
642 
643 	VDBG(midi, "%s()\n", __func__);
644 	return 0;
645 }
646 
647 static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
648 {
649 	struct f_midi *midi = substream->rmidi->private_data;
650 
651 	if (!midi->in_port[substream->number])
652 		return;
653 
654 	VDBG(midi, "%s() %d\n", __func__, up);
655 	midi->in_port[substream->number]->active = up;
656 	if (up)
657 		tasklet_hi_schedule(&midi->tasklet);
658 }
659 
660 static int f_midi_out_open(struct snd_rawmidi_substream *substream)
661 {
662 	struct f_midi *midi = substream->rmidi->private_data;
663 
664 	if (substream->number >= MAX_PORTS)
665 		return -EINVAL;
666 
667 	VDBG(midi, "%s()\n", __func__);
668 	midi->out_substream[substream->number] = substream;
669 	return 0;
670 }
671 
672 static int f_midi_out_close(struct snd_rawmidi_substream *substream)
673 {
674 	struct f_midi *midi = substream->rmidi->private_data;
675 
676 	VDBG(midi, "%s()\n", __func__);
677 	return 0;
678 }
679 
680 static void f_midi_out_trigger(struct snd_rawmidi_substream *substream, int up)
681 {
682 	struct f_midi *midi = substream->rmidi->private_data;
683 
684 	VDBG(midi, "%s()\n", __func__);
685 
686 	if (up)
687 		set_bit(substream->number, &midi->out_triggered);
688 	else
689 		clear_bit(substream->number, &midi->out_triggered);
690 }
691 
692 static struct snd_rawmidi_ops gmidi_in_ops = {
693 	.open = f_midi_in_open,
694 	.close = f_midi_in_close,
695 	.trigger = f_midi_in_trigger,
696 };
697 
698 static struct snd_rawmidi_ops gmidi_out_ops = {
699 	.open = f_midi_out_open,
700 	.close = f_midi_out_close,
701 	.trigger = f_midi_out_trigger
702 };
703 
704 static inline void f_midi_unregister_card(struct f_midi *midi)
705 {
706 	if (midi->card) {
707 		snd_card_free(midi->card);
708 		midi->card = NULL;
709 	}
710 }
711 
712 /* register as a sound "card" */
713 static int f_midi_register_card(struct f_midi *midi)
714 {
715 	struct snd_card *card;
716 	struct snd_rawmidi *rmidi;
717 	int err;
718 	static struct snd_device_ops ops = {
719 		.dev_free = f_midi_snd_free,
720 	};
721 
722 	err = snd_card_new(&midi->gadget->dev, midi->index, midi->id,
723 			   THIS_MODULE, 0, &card);
724 	if (err < 0) {
725 		ERROR(midi, "snd_card_new() failed\n");
726 		goto fail;
727 	}
728 	midi->card = card;
729 
730 	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, midi, &ops);
731 	if (err < 0) {
732 		ERROR(midi, "snd_device_new() failed: error %d\n", err);
733 		goto fail;
734 	}
735 
736 	strcpy(card->driver, f_midi_longname);
737 	strcpy(card->longname, f_midi_longname);
738 	strcpy(card->shortname, f_midi_shortname);
739 
740 	/* Set up rawmidi */
741 	snd_component_add(card, "MIDI");
742 	err = snd_rawmidi_new(card, card->longname, 0,
743 			      midi->out_ports, midi->in_ports, &rmidi);
744 	if (err < 0) {
745 		ERROR(midi, "snd_rawmidi_new() failed: error %d\n", err);
746 		goto fail;
747 	}
748 	midi->rmidi = rmidi;
749 	midi->in_last_port = 0;
750 	strcpy(rmidi->name, card->shortname);
751 	rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
752 			    SNDRV_RAWMIDI_INFO_INPUT |
753 			    SNDRV_RAWMIDI_INFO_DUPLEX;
754 	rmidi->private_data = midi;
755 
756 	/*
757 	 * Yes, rawmidi OUTPUT = USB IN, and rawmidi INPUT = USB OUT.
758 	 * It's an upside-down world being a gadget.
759 	 */
760 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &gmidi_in_ops);
761 	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &gmidi_out_ops);
762 
763 	/* register it - we're ready to go */
764 	err = snd_card_register(card);
765 	if (err < 0) {
766 		ERROR(midi, "snd_card_register() failed\n");
767 		goto fail;
768 	}
769 
770 	VDBG(midi, "%s() finished ok\n", __func__);
771 	return 0;
772 
773 fail:
774 	f_midi_unregister_card(midi);
775 	return err;
776 }
777 
778 /* MIDI function driver setup/binding */
779 
780 static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
781 {
782 	struct usb_descriptor_header **midi_function;
783 	struct usb_midi_in_jack_descriptor jack_in_ext_desc[MAX_PORTS];
784 	struct usb_midi_in_jack_descriptor jack_in_emb_desc[MAX_PORTS];
785 	struct usb_midi_out_jack_descriptor_1 jack_out_ext_desc[MAX_PORTS];
786 	struct usb_midi_out_jack_descriptor_1 jack_out_emb_desc[MAX_PORTS];
787 	struct usb_composite_dev *cdev = c->cdev;
788 	struct f_midi *midi = func_to_midi(f);
789 	struct usb_string *us;
790 	int status, n, jack = 1, i = 0;
791 
792 	midi->gadget = cdev->gadget;
793 	tasklet_init(&midi->tasklet, f_midi_in_tasklet, (unsigned long) midi);
794 	status = f_midi_register_card(midi);
795 	if (status < 0)
796 		goto fail_register;
797 
798 	/* maybe allocate device-global string ID */
799 	us = usb_gstrings_attach(c->cdev, midi_strings,
800 				 ARRAY_SIZE(midi_string_defs));
801 	if (IS_ERR(us)) {
802 		status = PTR_ERR(us);
803 		goto fail;
804 	}
805 	ac_interface_desc.iInterface = us[STRING_FUNC_IDX].id;
806 
807 	/* We have two interfaces, AudioControl and MIDIStreaming */
808 	status = usb_interface_id(c, f);
809 	if (status < 0)
810 		goto fail;
811 	ac_interface_desc.bInterfaceNumber = status;
812 
813 	status = usb_interface_id(c, f);
814 	if (status < 0)
815 		goto fail;
816 	ms_interface_desc.bInterfaceNumber = status;
817 	ac_header_desc.baInterfaceNr[0] = status;
818 	midi->ms_id = status;
819 
820 	status = -ENODEV;
821 
822 	/* allocate instance-specific endpoints */
823 	midi->in_ep = usb_ep_autoconfig(cdev->gadget, &bulk_in_desc);
824 	if (!midi->in_ep)
825 		goto fail;
826 
827 	midi->out_ep = usb_ep_autoconfig(cdev->gadget, &bulk_out_desc);
828 	if (!midi->out_ep)
829 		goto fail;
830 
831 	/* allocate temporary function list */
832 	midi_function = kcalloc((MAX_PORTS * 4) + 9, sizeof(*midi_function),
833 				GFP_KERNEL);
834 	if (!midi_function) {
835 		status = -ENOMEM;
836 		goto fail;
837 	}
838 
839 	/*
840 	 * construct the function's descriptor set. As the number of
841 	 * input and output MIDI ports is configurable, we have to do
842 	 * it that way.
843 	 */
844 
845 	/* add the headers - these are always the same */
846 	midi_function[i++] = (struct usb_descriptor_header *) &ac_interface_desc;
847 	midi_function[i++] = (struct usb_descriptor_header *) &ac_header_desc;
848 	midi_function[i++] = (struct usb_descriptor_header *) &ms_interface_desc;
849 
850 	/* calculate the header's wTotalLength */
851 	n = USB_DT_MS_HEADER_SIZE
852 		+ (midi->in_ports + midi->out_ports) *
853 			(USB_DT_MIDI_IN_SIZE + USB_DT_MIDI_OUT_SIZE(1));
854 	ms_header_desc.wTotalLength = cpu_to_le16(n);
855 
856 	midi_function[i++] = (struct usb_descriptor_header *) &ms_header_desc;
857 
858 	/* configure the external IN jacks, each linked to an embedded OUT jack */
859 	for (n = 0; n < midi->in_ports; n++) {
860 		struct usb_midi_in_jack_descriptor *in_ext = &jack_in_ext_desc[n];
861 		struct usb_midi_out_jack_descriptor_1 *out_emb = &jack_out_emb_desc[n];
862 
863 		in_ext->bLength			= USB_DT_MIDI_IN_SIZE;
864 		in_ext->bDescriptorType		= USB_DT_CS_INTERFACE;
865 		in_ext->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
866 		in_ext->bJackType		= USB_MS_EXTERNAL;
867 		in_ext->bJackID			= jack++;
868 		in_ext->iJack			= 0;
869 		midi_function[i++] = (struct usb_descriptor_header *) in_ext;
870 
871 		out_emb->bLength		= USB_DT_MIDI_OUT_SIZE(1);
872 		out_emb->bDescriptorType	= USB_DT_CS_INTERFACE;
873 		out_emb->bDescriptorSubtype	= USB_MS_MIDI_OUT_JACK;
874 		out_emb->bJackType		= USB_MS_EMBEDDED;
875 		out_emb->bJackID		= jack++;
876 		out_emb->bNrInputPins		= 1;
877 		out_emb->pins[0].baSourcePin	= 1;
878 		out_emb->pins[0].baSourceID	= in_ext->bJackID;
879 		out_emb->iJack			= 0;
880 		midi_function[i++] = (struct usb_descriptor_header *) out_emb;
881 
882 		/* link it to the endpoint */
883 		ms_in_desc.baAssocJackID[n] = out_emb->bJackID;
884 	}
885 
886 	/* configure the external OUT jacks, each linked to an embedded IN jack */
887 	for (n = 0; n < midi->out_ports; n++) {
888 		struct usb_midi_in_jack_descriptor *in_emb = &jack_in_emb_desc[n];
889 		struct usb_midi_out_jack_descriptor_1 *out_ext = &jack_out_ext_desc[n];
890 
891 		in_emb->bLength			= USB_DT_MIDI_IN_SIZE;
892 		in_emb->bDescriptorType		= USB_DT_CS_INTERFACE;
893 		in_emb->bDescriptorSubtype	= USB_MS_MIDI_IN_JACK;
894 		in_emb->bJackType		= USB_MS_EMBEDDED;
895 		in_emb->bJackID			= jack++;
896 		in_emb->iJack			= 0;
897 		midi_function[i++] = (struct usb_descriptor_header *) in_emb;
898 
899 		out_ext->bLength =		USB_DT_MIDI_OUT_SIZE(1);
900 		out_ext->bDescriptorType =	USB_DT_CS_INTERFACE;
901 		out_ext->bDescriptorSubtype =	USB_MS_MIDI_OUT_JACK;
902 		out_ext->bJackType =		USB_MS_EXTERNAL;
903 		out_ext->bJackID =		jack++;
904 		out_ext->bNrInputPins =		1;
905 		out_ext->iJack =		0;
906 		out_ext->pins[0].baSourceID =	in_emb->bJackID;
907 		out_ext->pins[0].baSourcePin =	1;
908 		midi_function[i++] = (struct usb_descriptor_header *) out_ext;
909 
910 		/* link it to the endpoint */
911 		ms_out_desc.baAssocJackID[n] = in_emb->bJackID;
912 	}
913 
914 	/* configure the endpoint descriptors ... */
915 	ms_out_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->in_ports);
916 	ms_out_desc.bNumEmbMIDIJack = midi->in_ports;
917 
918 	ms_in_desc.bLength = USB_DT_MS_ENDPOINT_SIZE(midi->out_ports);
919 	ms_in_desc.bNumEmbMIDIJack = midi->out_ports;
920 
921 	/* ... and add them to the list */
922 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_out_desc;
923 	midi_function[i++] = (struct usb_descriptor_header *) &ms_out_desc;
924 	midi_function[i++] = (struct usb_descriptor_header *) &bulk_in_desc;
925 	midi_function[i++] = (struct usb_descriptor_header *) &ms_in_desc;
926 	midi_function[i++] = NULL;
927 
928 	/*
929 	 * support all relevant hardware speeds... we expect that when
930 	 * hardware is dual speed, all bulk-capable endpoints work at
931 	 * both speeds
932 	 */
933 	/* copy descriptors, and track endpoint copies */
934 	f->fs_descriptors = usb_copy_descriptors(midi_function);
935 	if (!f->fs_descriptors)
936 		goto fail_f_midi;
937 
938 	if (gadget_is_dualspeed(c->cdev->gadget)) {
939 		bulk_in_desc.wMaxPacketSize = cpu_to_le16(512);
940 		bulk_out_desc.wMaxPacketSize = cpu_to_le16(512);
941 		f->hs_descriptors = usb_copy_descriptors(midi_function);
942 		if (!f->hs_descriptors)
943 			goto fail_f_midi;
944 	}
945 
946 	kfree(midi_function);
947 
948 	return 0;
949 
950 fail_f_midi:
951 	kfree(midi_function);
952 	usb_free_descriptors(f->hs_descriptors);
953 fail:
954 	f_midi_unregister_card(midi);
955 fail_register:
956 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
957 
958 	return status;
959 }
960 
961 static inline struct f_midi_opts *to_f_midi_opts(struct config_item *item)
962 {
963 	return container_of(to_config_group(item), struct f_midi_opts,
964 			    func_inst.group);
965 }
966 
967 static void midi_attr_release(struct config_item *item)
968 {
969 	struct f_midi_opts *opts = to_f_midi_opts(item);
970 
971 	usb_put_function_instance(&opts->func_inst);
972 }
973 
974 static struct configfs_item_operations midi_item_ops = {
975 	.release	= midi_attr_release,
976 };
977 
978 #define F_MIDI_OPT(name, test_limit, limit)				\
979 static ssize_t f_midi_opts_##name##_show(struct config_item *item, char *page) \
980 {									\
981 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
982 	int result;							\
983 									\
984 	mutex_lock(&opts->lock);					\
985 	result = sprintf(page, "%d\n", opts->name);			\
986 	mutex_unlock(&opts->lock);					\
987 									\
988 	return result;							\
989 }									\
990 									\
991 static ssize_t f_midi_opts_##name##_store(struct config_item *item,	\
992 					 const char *page, size_t len)	\
993 {									\
994 	struct f_midi_opts *opts = to_f_midi_opts(item);		\
995 	int ret;							\
996 	u32 num;							\
997 									\
998 	mutex_lock(&opts->lock);					\
999 	if (opts->refcnt) {						\
1000 		ret = -EBUSY;						\
1001 		goto end;						\
1002 	}								\
1003 									\
1004 	ret = kstrtou32(page, 0, &num);					\
1005 	if (ret)							\
1006 		goto end;						\
1007 									\
1008 	if (test_limit && num > limit) {				\
1009 		ret = -EINVAL;						\
1010 		goto end;						\
1011 	}								\
1012 	opts->name = num;						\
1013 	ret = len;							\
1014 									\
1015 end:									\
1016 	mutex_unlock(&opts->lock);					\
1017 	return ret;							\
1018 }									\
1019 									\
1020 CONFIGFS_ATTR(f_midi_opts_, name);
1021 
1022 F_MIDI_OPT(index, true, SNDRV_CARDS);
1023 F_MIDI_OPT(buflen, false, 0);
1024 F_MIDI_OPT(qlen, false, 0);
1025 F_MIDI_OPT(in_ports, true, MAX_PORTS);
1026 F_MIDI_OPT(out_ports, true, MAX_PORTS);
1027 
1028 static ssize_t f_midi_opts_id_show(struct config_item *item, char *page)
1029 {
1030 	struct f_midi_opts *opts = to_f_midi_opts(item);
1031 	int result;
1032 
1033 	mutex_lock(&opts->lock);
1034 	if (opts->id) {
1035 		result = strlcpy(page, opts->id, PAGE_SIZE);
1036 	} else {
1037 		page[0] = 0;
1038 		result = 0;
1039 	}
1040 
1041 	mutex_unlock(&opts->lock);
1042 
1043 	return result;
1044 }
1045 
1046 static ssize_t f_midi_opts_id_store(struct config_item *item,
1047 				    const char *page, size_t len)
1048 {
1049 	struct f_midi_opts *opts = to_f_midi_opts(item);
1050 	int ret;
1051 	char *c;
1052 
1053 	mutex_lock(&opts->lock);
1054 	if (opts->refcnt) {
1055 		ret = -EBUSY;
1056 		goto end;
1057 	}
1058 
1059 	c = kstrndup(page, len, GFP_KERNEL);
1060 	if (!c) {
1061 		ret = -ENOMEM;
1062 		goto end;
1063 	}
1064 	if (opts->id_allocated)
1065 		kfree(opts->id);
1066 	opts->id = c;
1067 	opts->id_allocated = true;
1068 	ret = len;
1069 end:
1070 	mutex_unlock(&opts->lock);
1071 	return ret;
1072 }
1073 
1074 CONFIGFS_ATTR(f_midi_opts_, id);
1075 
1076 static struct configfs_attribute *midi_attrs[] = {
1077 	&f_midi_opts_attr_index,
1078 	&f_midi_opts_attr_buflen,
1079 	&f_midi_opts_attr_qlen,
1080 	&f_midi_opts_attr_in_ports,
1081 	&f_midi_opts_attr_out_ports,
1082 	&f_midi_opts_attr_id,
1083 	NULL,
1084 };
1085 
1086 static struct config_item_type midi_func_type = {
1087 	.ct_item_ops	= &midi_item_ops,
1088 	.ct_attrs	= midi_attrs,
1089 	.ct_owner	= THIS_MODULE,
1090 };
1091 
1092 static void f_midi_free_inst(struct usb_function_instance *f)
1093 {
1094 	struct f_midi_opts *opts;
1095 
1096 	opts = container_of(f, struct f_midi_opts, func_inst);
1097 
1098 	if (opts->id_allocated)
1099 		kfree(opts->id);
1100 
1101 	kfree(opts);
1102 }
1103 
1104 static struct usb_function_instance *f_midi_alloc_inst(void)
1105 {
1106 	struct f_midi_opts *opts;
1107 
1108 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1109 	if (!opts)
1110 		return ERR_PTR(-ENOMEM);
1111 
1112 	mutex_init(&opts->lock);
1113 	opts->func_inst.free_func_inst = f_midi_free_inst;
1114 	opts->index = SNDRV_DEFAULT_IDX1;
1115 	opts->id = SNDRV_DEFAULT_STR1;
1116 	opts->buflen = 256;
1117 	opts->qlen = 32;
1118 	opts->in_ports = 1;
1119 	opts->out_ports = 1;
1120 
1121 	config_group_init_type_name(&opts->func_inst.group, "",
1122 				    &midi_func_type);
1123 
1124 	return &opts->func_inst;
1125 }
1126 
1127 static void f_midi_free(struct usb_function *f)
1128 {
1129 	struct f_midi *midi;
1130 	struct f_midi_opts *opts;
1131 	int i;
1132 
1133 	midi = func_to_midi(f);
1134 	opts = container_of(f->fi, struct f_midi_opts, func_inst);
1135 	kfree(midi->id);
1136 	mutex_lock(&opts->lock);
1137 	for (i = opts->in_ports - 1; i >= 0; --i)
1138 		kfree(midi->in_port[i]);
1139 	kfifo_free(&midi->in_req_fifo);
1140 	kfree(midi);
1141 	--opts->refcnt;
1142 	mutex_unlock(&opts->lock);
1143 }
1144 
1145 static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
1146 {
1147 	struct usb_composite_dev *cdev = f->config->cdev;
1148 	struct f_midi *midi = func_to_midi(f);
1149 	struct snd_card *card;
1150 
1151 	DBG(cdev, "unbind\n");
1152 
1153 	/* just to be sure */
1154 	f_midi_disable(f);
1155 
1156 	card = midi->card;
1157 	midi->card = NULL;
1158 	if (card)
1159 		snd_card_free(card);
1160 
1161 	usb_free_all_descriptors(f);
1162 }
1163 
1164 static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
1165 {
1166 	struct f_midi *midi;
1167 	struct f_midi_opts *opts;
1168 	int status, i;
1169 
1170 	opts = container_of(fi, struct f_midi_opts, func_inst);
1171 
1172 	mutex_lock(&opts->lock);
1173 	/* sanity check */
1174 	if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
1175 		mutex_unlock(&opts->lock);
1176 		return ERR_PTR(-EINVAL);
1177 	}
1178 
1179 	/* allocate and initialize one new instance */
1180 	midi = kzalloc(sizeof(*midi), GFP_KERNEL);
1181 	if (!midi) {
1182 		mutex_unlock(&opts->lock);
1183 		return ERR_PTR(-ENOMEM);
1184 	}
1185 
1186 	for (i = 0; i < opts->in_ports; i++) {
1187 		struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
1188 
1189 		if (!port) {
1190 			status = -ENOMEM;
1191 			mutex_unlock(&opts->lock);
1192 			goto setup_fail;
1193 		}
1194 
1195 		port->midi = midi;
1196 		port->active = 0;
1197 		port->cable = i;
1198 		midi->in_port[i] = port;
1199 	}
1200 
1201 	/* set up ALSA midi devices */
1202 	midi->id = kstrdup(opts->id, GFP_KERNEL);
1203 	if (opts->id && !midi->id) {
1204 		status = -ENOMEM;
1205 		mutex_unlock(&opts->lock);
1206 		goto setup_fail;
1207 	}
1208 	midi->in_ports = opts->in_ports;
1209 	midi->out_ports = opts->out_ports;
1210 	midi->index = opts->index;
1211 	midi->buflen = opts->buflen;
1212 	midi->qlen = opts->qlen;
1213 	midi->in_last_port = 0;
1214 
1215 	status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
1216 	if (status)
1217 		goto setup_fail;
1218 
1219 	++opts->refcnt;
1220 	mutex_unlock(&opts->lock);
1221 
1222 	midi->func.name		= "gmidi function";
1223 	midi->func.bind		= f_midi_bind;
1224 	midi->func.unbind	= f_midi_unbind;
1225 	midi->func.set_alt	= f_midi_set_alt;
1226 	midi->func.disable	= f_midi_disable;
1227 	midi->func.free_func	= f_midi_free;
1228 
1229 	return &midi->func;
1230 
1231 setup_fail:
1232 	for (--i; i >= 0; i--)
1233 		kfree(midi->in_port[i]);
1234 	kfree(midi);
1235 	return ERR_PTR(status);
1236 }
1237 
1238 DECLARE_USB_FUNCTION_INIT(midi, f_midi_alloc_inst, f_midi_alloc);
1239