summaryrefslogtreecommitdiffstats
path: root/sound/core/seq/seq_ports.c
blob: 3bf7d73ac52ebbed66858c695050f25cde25156b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
/*
 *   ALSA sequencer Ports
 *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
 *                         Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/core.h>
#include <linux/slab.h>
#include "seq_system.h"
#include "seq_ports.h"
#include "seq_clientmgr.h"

/*

   registration of client ports

 */


/* 

NOTE: the current implementation of the port structure as a linked list is
not optimal for clients that have many ports. For sending messages to all
subscribers of a port we first need to find the address of the port
structure, which means we have to traverse the list. A direct access table
(array) would be better, but big preallocated arrays waste memory.

Possible actions:

1) leave it this way, a client does normaly does not have more than a few
ports

2) replace the linked list of ports by a array of pointers which is
dynamicly kmalloced. When a port is added or deleted we can simply allocate
a new array, copy the corresponding pointers, and delete the old one. We
then only need a pointer to this array, and an integer that tells us how
much elements are in array.

*/

/* return pointer to port structure - port is locked if found */
struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client,
						 int num)
{
	struct snd_seq_client_port *port;

	if (client == NULL)
		return NULL;
	read_lock(&client->ports_lock);
	list_for_each_entry(port, &client->ports_list_head, list) {
		if (port->addr.port == num) {
			if (port->closing)
				break; /* deleting now */
			snd_use_lock_use(&port->use_lock);
			read_unlock(&client->ports_lock);
			return port;
		}
	}
	read_unlock(&client->ports_lock);
	return NULL;		/* not found */
}


/* search for the next port - port is locked if found */
struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
						       struct snd_seq_port_info *pinfo)
{
	int num;
	struct snd_seq_client_port *port, *found;

	num = pinfo->addr.port;
	found = NULL;
	read_lock(&client->ports_lock);
	list_for_each_entry(port, &client->ports_list_head, list) {
		if (port->addr.port < num)
			continue;
		if (port->addr.port == num) {
			found = port;
			break;
		}
		if (found == NULL || port->addr.port < found->addr.port)
			found = port;
	}
	if (found) {
		if (found->closing)
			found = NULL;
		else
			snd_use_lock_use(&found->use_lock);
	}
	read_unlock(&client->ports_lock);
	return found;
}


/* initialize snd_seq_port_subs_info */
static void port_subs_info_init(struct snd_seq_port_subs_info *grp)
{
	INIT_LIST_HEAD(&grp->list_head);
	grp->count = 0;
	grp->exclusive = 0;
	rwlock_init(&grp->list_lock);
	init_rwsem(&grp->list_mutex);
	grp->open = NULL;
	grp->close = NULL;
}


/* create a port, port number is returned (-1 on failure) */
struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client,
						int port)
{
	unsigned long flags;
	struct snd_seq_client_port *new_port, *p;
	int num = -1;
	
	/* sanity check */
	if (snd_BUG_ON(!client))
		return NULL;

	if (client->num_ports >= SNDRV_SEQ_MAX_PORTS - 1) {
		snd_printk(KERN_WARNING "too many ports for client %d\n", client->number);
		return NULL;
	}

	/* create a new port */
	new_port = kzalloc(sizeof(*new_port), GFP_KERNEL);
	if (! new_port) {
		snd_printd("malloc failed for registering client port\n");
		return NULL;	/* failure, out of memory */
	}
	/* init port data */
	new_port->addr.client = client->number;
	new_port->addr.port = -1;
	new_port->owner = THIS_MODULE;
	sprintf(new_port->name, "port-%d", num);
	snd_use_lock_init(&new_port->use_lock);
	port_subs_info_init(&new_port->c_src);
	port_subs_info_init(&new_port->c_dest);

	num = port >= 0 ? port : 0;
	mutex_lock(&client->ports_mutex);
	write_lock_irqsave(&client->ports_lock, flags);
	list_for_each_entry(p, &client->ports_list_head, list) {
		if (p->addr.port > num)
			break;
		if (port < 0) /* auto-probe mode */
			num = p->addr.port + 1;
	}
	/* insert the new port */
	list_add_tail(&new_port->list, &p->list);
	client->num_ports++;
	new_port->addr.port = num;	/* store the port number in the port */
	write_unlock_irqrestore(&client->ports_lock, flags);
	mutex_unlock(&client->ports_mutex);
	sprintf(new_port->name, "port-%d", num);

	return new_port;
}

/* */
enum group_type {
	SRC_LIST, DEST_LIST
};

static int subscribe_port(struct snd_seq_client *client,
			  struct snd_seq_client_port *port,
			  struct snd_seq_port_subs_info *grp,
			  struct snd_seq_port_subscribe *info, int send_ack);
static int unsubscribe_port(struct snd_seq_client *client,
			    struct snd_seq_client_port *port,
			    struct snd_seq_port_subs_info *grp,
			    struct snd_seq_port_subscribe *info, int send_ack);


static struct snd_seq_client_port *get_client_port(struct snd_seq_addr *addr,
						   struct snd_seq_client **cp)
{
	struct snd_seq_client_port *p;
	*cp = snd_seq_client_use_ptr(addr->client);
	if (*cp) {
		p = snd_seq_port_use_ptr(*cp, addr->port);
		if (! p) {
			snd_seq_client_unlock(*cp);
			*cp = NULL;
		}
		return p;
	}
	return NULL;
}

/*
 * remove all subscribers on the list
 * this is called from port_delete, for each src and dest list.
 */
static void clear_subscriber_list(struct snd_seq_client *client,
				  struct snd_seq_client_port *port,
				  struct snd_seq_port_subs_info *grp,
				  int grptype)
{
	struct list_head *p, *n;

	list_for_each_safe(p, n, &grp->list_head) {
		struct snd_seq_subscribers *subs;
		struct snd_seq_client *c;
		struct snd_seq_client_port *aport;

		if (grptype == SRC_LIST) {
			subs = list_entry(p, struct snd_seq_subscribers, src_list);
			aport = get_client_port(&subs->info.dest, &c);
		} else {
			subs = list_entry(p, struct snd_seq_subscribers, dest_list);
			aport = get_client_port(&subs->info.sender, &c);
		}
		list_del(p);
		unsubscribe_port(client, port, grp, &subs->info, 0);
		if (!aport) {
			/* looks like the connected port is being deleted.
			 * we decrease the counter, and when both ports are deleted
			 * remove the subscriber info
			 */
			if (atomic_dec_and_test(&subs->ref_count))
				kfree(subs);
		} else {
			/* ok we got the connected port */
			struct snd_seq_port_subs_info *agrp;
			agrp = (grptype == SRC_LIST) ? &aport->c_dest : &aport->c_src;
			down_write(&agrp->list_mutex);
			if (grptype == SRC_LIST)
				list_del(&subs->dest_list);
			else
				list_del(&subs->src_list);
			up_write(&agrp->list_mutex);
			unsubscribe_port(c, aport, agrp, &subs->info, 1);
			kfree(subs);
			snd_seq_port_unlock(aport);
			snd_seq_client_unlock(c);
		}
	}
}

/* delete port data */
static int port_delete(struct snd_seq_client *client,
		       struct snd_seq_client_port *port)
{
	/* set closing flag and wait for all port access are gone */
	port->closing = 1;
	snd_use_lock_sync(&port->use_lock); 

	/* clear subscribers info */
	clear_subscriber_list(client, port, &port->c_src, SRC_LIST);
	clear_subscriber_list(client, port, &port->c_dest, DEST_LIST);

	if (port->private_free)
		port->private_free(port->private_data);

	snd_BUG_ON(port->c_src.count != 0);
	snd_BUG_ON(port->c_dest.count != 0);

	kfree(port);
	return 0;
}


/* delete a port with the given port id */
int snd_seq_delete_port(struct snd_seq_client *client, int port)
{
	unsigned long flags;
	struct snd_seq_client_port *found = NULL, *p;

	mutex_lock(&client->ports_mutex);
	write_lock_irqsave(&client->ports_lock, flags);
	list_for_each_entry(p, &client->ports_list_head, list) {
		if (p->addr.port == port) {
			/* ok found.  delete from the list at first */
			list_del(&p->list);
			client->num_ports--;
			found = p;
			break;
		}
	}
	write_unlock_irqrestore(&client->ports_lock, flags);
	mutex_unlock(&client->ports_mutex);
	if (found)
		return port_delete(client, found);
	else
		return -ENOENT;
}

/* delete the all ports belonging to the given client */
int snd_seq_delete_all_ports(struct snd_seq_client *client)
{
	unsigned long flags;
	struct list_head deleted_list;
	struct snd_seq_client_port *port, *tmp;
	
	/* move the port list to deleted_list, and
	 * clear the port list in the client data.
	 */
	mutex_lock(&client->ports_mutex);
	write_lock_irqsave(&client->ports_lock, flags);
	if (! list_empty(&client->ports_list_head)) {
		list_add(&deleted_list, &client->ports_list_head);
		list_del_init(&client->ports_list_head);
	} else {
		INIT_LIST_HEAD(&deleted_list);
	}
	client->num_ports = 0;
	write_unlock_irqrestore(&client->ports_lock, flags);

	/* remove each port in deleted_list */
	list_for_each_entry_safe(port, tmp, &deleted_list, list) {
		list_del(&port->list);
		snd_seq_system_client_ev_port_exit(port->addr.client, port->addr.port);
		port_delete(client, port);
	}
	mutex_unlock(&client->ports_mutex);
	return 0;
}

/* set port info fields */
int snd_seq_set_port_info(struct snd_seq_client_port * port,
			  struct snd_seq_port_info * info)
{
	if (snd_BUG_ON(!port || !info))
		return -EINVAL;

	/* set port name */
	if (info->name[0])
		strlcpy(port->name, info->name, sizeof(port->name));
	
	/* set capabilities */
	port->capability = info->capability;
	
	/* get port type */
	port->type = info->type;

	/* information about supported channels/voices */
	port->midi_channels = info->midi_channels;
	port->midi_voices = info->midi_voices;
	port->synth_voices = info->synth_voices;

	/* timestamping */
	port->timestamping = (info->flags & SNDRV_SEQ_PORT_FLG_TIMESTAMP) ? 1 : 0;
	port->time_real = (info->flags & SNDRV_SEQ_PORT_FLG_TIME_REAL) ? 1 : 0;
	port->time_queue = info->time_queue;

	return 0;
}

/* get port info fields */
int snd_seq_get_port_info(struct snd_seq_client_port * port,
			  struct snd_seq_port_info * info)
{
	if (snd_BUG_ON(!port || !info))
		return -EINVAL;

	/* get port name */
	strlcpy(info->name, port->name, sizeof(info->name));
	
	/* get capabilities */
	info->capability = port->capability;

	/* get port type */
	info->type = port->type;

	/* information about supported channels/voices */
	info->midi_channels = port->midi_channels;
	info->midi_voices = port->midi_voices;
	info->synth_voices = port->synth_voices;

	/* get subscriber counts */
	info->read_use = port->c_src.count;
	info->write_use = port->c_dest.count;
	
	/* timestamping */
	info->flags = 0;
	if (port->timestamping) {
		info->flags |= SNDRV_SEQ_PORT_FLG_TIMESTAMP;
		if (port->time_real)
			info->flags |= SNDRV_SEQ_PORT_FLG_TIME_REAL;
		info->time_queue = port->time_queue;
	}

	return 0;
}



/*
 * call callback functions (if any):
 * the callbacks are invoked only when the first (for connection) or
 * the last subscription (for disconnection) is done.  Second or later
 * subscription results in increment of counter, but no callback is
 * invoked.
 * This feature is useful if these callbacks are associated with
 * initialization or termination of devices (see seq_midi.c).
 *
 * If callback_all option is set, the callback function is invoked
 * at each connnection/disconnection. 
 */

static int subscribe_port(struct snd_seq_client *client,
			  struct snd_seq_client_port *port,
			  struct snd_seq_port_subs_info *grp,
			  struct snd_seq_port_subscribe *info,
			  int send_ack)
{
	int err = 0;

	if (!try_module_get(port->owner))
		return -EFAULT;
	grp->count++;
	if (grp->open && (port->callback_all || grp->count == 1)) {
		err = grp->open(port->private_data, info);
		if (err < 0) {
			module_put(port->owner);
			grp->count--;
		}
	}
	if (err >= 0 && send_ack && client->type == USER_CLIENT)
		snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
						   info, SNDRV_SEQ_EVENT_PORT_SUBSCRIBED);

	return err;
}

static int unsubscribe_port(struct snd_seq_client *client,
			    struct snd_seq_client_port *port,
			    struct snd_seq_port_subs_info *grp,
			    struct snd_seq_port_subscribe *info,
			    int send_ack)
{
	int err = 0;

	if (! grp->count)
		return -EINVAL;
	grp->count--;
	if (grp->close && (port->callback_all || grp->count == 0))
		err = grp->close(port->private_data, info);
	if (send_ack && client->type == USER_CLIENT)
		snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
						   info, SNDRV_SEQ_EVENT_PORT_UNSUBSCRIBED);
	module_put(port->owner);
	return err;
}



/* check if both addresses are identical */
static inline int addr_match(struct snd_seq_addr *r, struct snd_seq_addr *s)
{
	return (r->client == s->client) && (r->port == s->port);
}

/* check the two subscribe info match */
/* if flags is zero, checks only sender and destination addresses */
static int match_subs_info(struct snd_seq_port_subscribe *r,
			   struct snd_seq_port_subscribe *s)
{
	if (addr_match(&r->sender, &s->sender) &&
	    addr_match(&r->dest, &s->dest)) {
		if (r->flags && r->flags == s->flags)
			return r->queue == s->queue;
		else if (! r->flags)
			return 1;
	}
	return 0;
}


/* connect two ports */
int snd_seq_port_connect(struct snd_seq_client *connector,
			 struct snd_seq_client *src_client,
			 struct snd_seq_client_port *src_port,
			 struct snd_seq_client *dest_client,
			 struct snd_seq_client_port *dest_port,
			 struct snd_seq_port_subscribe *info)
{
	struct snd_seq_port_subs_info *src = &src_port->c_src;
	struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
	struct snd_seq_subscribers *subs, *s;
	int err, src_called = 0;
	unsigned long flags;
	int exclusive;

	subs = kzalloc(sizeof(*subs), GFP_KERNEL);
	if (! subs)
		return -ENOMEM;

	subs->info = *info;
	atomic_set(&subs->ref_count, 2);

	down_write(&src->list_mutex);
	down_write_nested(&dest->list_mutex, SINGLE_DEPTH_NESTING);

	exclusive = info->flags & SNDRV_SEQ_PORT_SUBS_EXCLUSIVE ? 1 : 0;
	err = -EBUSY;
	if (exclusive) {
		if (! list_empty(&src->list_head) || ! list_empty(&dest->list_head))
			goto __error;
	} else {
		if (src->exclusive || dest->exclusive)
			goto __error;
		/* check whether already exists */
		list_for_each_entry(s, &src->list_head, src_list) {
			if (match_subs_info(info, &s->info))
				goto __error;
		}
		list_for_each_entry(s, &dest->list_head, dest_list) {
			if (match_subs_info(info, &s->info))
				goto __error;
		}
	}

	if ((err = subscribe_port(src_client, src_port, src, info,
				  connector->number != src_client->number)) < 0)
		goto __error;
	src_called = 1;

	if ((err = subscribe_port(dest_client, dest_port, dest, info,
				  connector->number != dest_client->number)) < 0)
		goto __error;

	/* add to list */
	write_lock_irqsave(&src->list_lock, flags);
	// write_lock(&dest->list_lock); // no other lock yet
	list_add_tail(&subs->src_list, &src->list_head);
	list_add_tail(&subs->dest_list, &dest->list_head);
	// write_unlock(&dest->list_lock); // no other lock yet
	write_unlock_irqrestore(&src->list_lock, flags);

	src->exclusive = dest->exclusive = exclusive;

	up_write(&dest->list_mutex);
	up_write(&src->list_mutex);
	return 0;

 __error:
	if (src_called)
		unsubscribe_port(src_client, src_port, src, info,
				 connector->number != src_client->number);
	kfree(subs);
	up_write(&dest->list_mutex);
	up_write(&src->list_mutex);
	return err;
}


/* remove the connection */
int snd_seq_port_disconnect(struct snd_seq_client *connector,
			    struct snd_seq_client *src_client,
			    struct snd_seq_client_port *src_port,
			    struct snd_seq_client *dest_client,
			    struct snd_seq_client_port *dest_port,
			    struct snd_seq_port_subscribe *info)
{
	struct snd_seq_port_subs_info *src = &src_port->c_src;
	struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
	struct snd_seq_subscribers *subs;
	int err = -ENOENT;
	unsigned long flags;

	down_write(&src->list_mutex);
	down_write_nested(&dest->list_mutex, SINGLE_DEPTH_NESTING);

	/* look for the connection */
	list_for_each_entry(subs, &src->list_head, src_list) {
		if (match_subs_info(info, &subs->info)) {
			write_lock_irqsave(&src->list_lock, flags);
			// write_lock(&dest->list_lock);  // no lock yet
			list_del(&subs->src_list);
			list_del(&subs->dest_list);
			// write_unlock(&dest->list_lock);
			write_unlock_irqrestore(&src->list_lock, flags);
			src->exclusive = dest->exclusive = 0;
			unsubscribe_port(src_client, src_port, src, info,
					 connector->number != src_client->number);
			unsubscribe_port(dest_client, dest_port, dest, info,
					 connector->number != dest_client->number);
			kfree(subs);
			err = 0;
			break;
		}
	}

	up_write(&dest->list_mutex);
	up_write(&src->list_mutex);
	return err;
}


/* get matched subscriber */
struct snd_seq_subscribers *snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
							  struct snd_seq_addr *dest_addr)
{
	struct snd_seq_subscribers *s, *found = NULL;

	down_read(&src_grp->list_mutex);
	list_for_each_entry(s, &src_grp->list_head, src_list) {
		if (addr_match(dest_addr, &s->info.dest)) {
			found = s;
			break;
		}
	}
	up_read(&src_grp->list_mutex);
	return found;
}

/*
 * Attach a device driver that wants to receive events from the
 * sequencer.  Returns the new port number on success.
 * A driver that wants to receive the events converted to midi, will
 * use snd_seq_midisynth_register_port().
 */
/* exported */
int snd_seq_event_port_attach(int client,
			      struct snd_seq_port_callback *pcbp,
			      int cap, int type, int midi_channels,
			      int midi_voices, char *portname)
{
	struct snd_seq_port_info portinfo;
	int  ret;

	/* Set up the port */
	memset(&portinfo, 0, sizeof(portinfo));
	portinfo.addr.client = client;
	strlcpy(portinfo.name, portname ? portname : "Unamed port",
		sizeof(portinfo.name));

	portinfo.capability = cap;
	portinfo.type = type;
	portinfo.kernel = pcbp;
	portinfo.midi_channels = midi_channels;
	portinfo.midi_voices = midi_voices;

	/* Create it */
	ret = snd_seq_kernel_client_ctl(client,
					SNDRV_SEQ_IOCTL_CREATE_PORT,
					&portinfo);

	if (ret >= 0)
		ret = portinfo.addr.port;

	return ret;
}

EXPORT_SYMBOL(snd_seq_event_port_attach);

/*
 * Detach the driver from a port.
 */
/* exported */
int snd_seq_event_port_detach(int client, int port)
{
	struct snd_seq_port_info portinfo;
	int  err;

	memset(&portinfo, 0, sizeof(portinfo));
	portinfo.addr.client = client;
	portinfo.addr.port   = port;
	err = snd_seq_kernel_client_ctl(client,
					SNDRV_SEQ_IOCTL_DELETE_PORT,
					&portinfo);

	return err;
}

EXPORT_SYMBOL(snd_seq_event_port_detach);
OpenPOWER on IntegriCloud