1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ALSA sequencer Timing queue handling
4 * Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
5 *
6 * MAJOR CHANGES
7 * Nov. 13, 1999 Takashi Iwai <iwai@ww.uni-erlangen.de>
8 * - Queues are allocated dynamically via ioctl.
9 * - When owner client is deleted, all owned queues are deleted, too.
10 * - Owner of unlocked queue is kept unmodified even if it is
11 * manipulated by other clients.
12 * - Owner field in SET_QUEUE_OWNER ioctl must be identical with the
13 * caller client. i.e. Changing owner to a third client is not
14 * allowed.
15 *
16 * Aug. 30, 2000 Takashi Iwai
17 * - Queues are managed in static array again, but with better way.
18 * The API itself is identical.
19 * - The queue is locked when struct snd_seq_queue pointer is returned via
20 * queueptr(). This pointer *MUST* be released afterward by
21 * queuefree(ptr).
22 * - Addition of experimental sync support.
23 */
24
25#include <linux/init.h>
26#include <linux/slab.h>
27#include <sound/core.h>
28
29#include "seq_memory.h"
30#include "seq_queue.h"
31#include "seq_clientmgr.h"
32#include "seq_fifo.h"
33#include "seq_timer.h"
34#include "seq_info.h"
35
36/* list of allocated queues */
37static struct snd_seq_queue *queue_list[SNDRV_SEQ_MAX_QUEUES];
38static DEFINE_SPINLOCK(queue_list_lock);
39/* number of queues allocated */
40static int num_queues;
41
42int snd_seq_queue_get_cur_queues(void)
43{
44 return num_queues;
45}
46
47/*----------------------------------------------------------------*/
48
49/* assign queue id and insert to list */
50static int queue_list_add(struct snd_seq_queue *q)
51{
52 int i;
53
54 guard(spinlock_irqsave)(l: &queue_list_lock);
55 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
56 if (! queue_list[i]) {
57 queue_list[i] = q;
58 q->queue = i;
59 num_queues++;
60 return i;
61 }
62 }
63 return -1;
64}
65
66static struct snd_seq_queue *queue_list_remove(int id, int client)
67{
68 struct snd_seq_queue *q;
69
70 guard(spinlock_irqsave)(l: &queue_list_lock);
71 q = queue_list[id];
72 if (q) {
73 guard(spinlock)(l: &q->owner_lock);
74 if (q->owner == client) {
75 /* found */
76 q->klocked = 1;
77 queue_list[id] = NULL;
78 num_queues--;
79 return q;
80 }
81 }
82 return NULL;
83}
84
85/*----------------------------------------------------------------*/
86
87/* create new queue (constructor) */
88static struct snd_seq_queue *queue_new(int owner, int locked)
89{
90 struct snd_seq_queue *q;
91
92 q = kzalloc(sizeof(*q), GFP_KERNEL);
93 if (!q)
94 return NULL;
95
96 spin_lock_init(&q->owner_lock);
97 spin_lock_init(&q->check_lock);
98 mutex_init(&q->timer_mutex);
99 snd_use_lock_init(&q->use_lock);
100 q->queue = -1;
101
102 q->tickq = snd_seq_prioq_new();
103 q->timeq = snd_seq_prioq_new();
104 q->timer = snd_seq_timer_new();
105 if (q->tickq == NULL || q->timeq == NULL || q->timer == NULL) {
106 snd_seq_prioq_delete(fifo: &q->tickq);
107 snd_seq_prioq_delete(fifo: &q->timeq);
108 snd_seq_timer_delete(tmr: &q->timer);
109 kfree(objp: q);
110 return NULL;
111 }
112
113 q->owner = owner;
114 q->locked = locked;
115 q->klocked = 0;
116
117 return q;
118}
119
120/* delete queue (destructor) */
121static void queue_delete(struct snd_seq_queue *q)
122{
123 /* stop and release the timer */
124 mutex_lock(&q->timer_mutex);
125 snd_seq_timer_stop(tmr: q->timer);
126 snd_seq_timer_close(q);
127 mutex_unlock(lock: &q->timer_mutex);
128 /* wait until access free */
129 snd_use_lock_sync(&q->use_lock);
130 /* release resources... */
131 snd_seq_prioq_delete(fifo: &q->tickq);
132 snd_seq_prioq_delete(fifo: &q->timeq);
133 snd_seq_timer_delete(tmr: &q->timer);
134
135 kfree(objp: q);
136}
137
138
139/*----------------------------------------------------------------*/
140
141/* delete all existing queues */
142void snd_seq_queues_delete(void)
143{
144 int i;
145
146 /* clear list */
147 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
148 if (queue_list[i])
149 queue_delete(q: queue_list[i]);
150 }
151}
152
153static void queue_use(struct snd_seq_queue *queue, int client, int use);
154
155/* allocate a new queue -
156 * return pointer to new queue or ERR_PTR(-errno) for error
157 * The new queue's use_lock is set to 1. It is the caller's responsibility to
158 * call snd_use_lock_free(&q->use_lock).
159 */
160struct snd_seq_queue *snd_seq_queue_alloc(int client, int locked, unsigned int info_flags)
161{
162 struct snd_seq_queue *q;
163
164 q = queue_new(owner: client, locked);
165 if (q == NULL)
166 return ERR_PTR(error: -ENOMEM);
167 q->info_flags = info_flags;
168 queue_use(queue: q, client, use: 1);
169 snd_use_lock_use(&q->use_lock);
170 if (queue_list_add(q) < 0) {
171 snd_use_lock_free(&q->use_lock);
172 queue_delete(q);
173 return ERR_PTR(error: -ENOMEM);
174 }
175 return q;
176}
177
178/* delete a queue - queue must be owned by the client */
179int snd_seq_queue_delete(int client, int queueid)
180{
181 struct snd_seq_queue *q;
182
183 if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
184 return -EINVAL;
185 q = queue_list_remove(id: queueid, client);
186 if (q == NULL)
187 return -EINVAL;
188 queue_delete(q);
189
190 return 0;
191}
192
193
194/* return pointer to queue structure for specified id */
195struct snd_seq_queue *queueptr(int queueid)
196{
197 struct snd_seq_queue *q;
198
199 if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
200 return NULL;
201 guard(spinlock_irqsave)(l: &queue_list_lock);
202 q = queue_list[queueid];
203 if (q)
204 snd_use_lock_use(&q->use_lock);
205 return q;
206}
207
208/* return the (first) queue matching with the specified name */
209struct snd_seq_queue *snd_seq_queue_find_name(char *name)
210{
211 int i;
212
213 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
214 struct snd_seq_queue *q __free(snd_seq_queue) = NULL;
215 q = queueptr(queueid: i);
216 if (q) {
217 if (strncmp(q->name, name, sizeof(q->name)) == 0)
218 return no_free_ptr(q);
219 }
220 }
221 return NULL;
222}
223
224
225/* -------------------------------------------------------- */
226
227#define MAX_CELL_PROCESSES_IN_QUEUE 1000
228
229void snd_seq_check_queue(struct snd_seq_queue *q, int atomic, int hop)
230{
231 struct snd_seq_event_cell *cell;
232 snd_seq_tick_time_t cur_tick;
233 snd_seq_real_time_t cur_time;
234 int processed = 0;
235
236 if (q == NULL)
237 return;
238
239 /* make this function non-reentrant */
240 scoped_guard(spinlock_irqsave, &q->check_lock) {
241 if (q->check_blocked) {
242 q->check_again = 1;
243 return; /* other thread is already checking queues */
244 }
245 q->check_blocked = 1;
246 }
247
248 __again:
249 /* Process tick queue... */
250 cur_tick = snd_seq_timer_get_cur_tick(tmr: q->timer);
251 for (;;) {
252 cell = snd_seq_prioq_cell_out(f: q->tickq, current_time: &cur_tick);
253 if (!cell)
254 break;
255 snd_seq_dispatch_event(cell, atomic, hop);
256 if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)
257 goto out; /* the rest processed at the next batch */
258 }
259
260 /* Process time queue... */
261 cur_time = snd_seq_timer_get_cur_time(tmr: q->timer, adjust_ktime: false);
262 for (;;) {
263 cell = snd_seq_prioq_cell_out(f: q->timeq, current_time: &cur_time);
264 if (!cell)
265 break;
266 snd_seq_dispatch_event(cell, atomic, hop);
267 if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)
268 goto out; /* the rest processed at the next batch */
269 }
270
271 out:
272 /* free lock */
273 scoped_guard(spinlock_irqsave, &q->check_lock) {
274 if (q->check_again) {
275 q->check_again = 0;
276 if (processed < MAX_CELL_PROCESSES_IN_QUEUE)
277 goto __again;
278 }
279 q->check_blocked = 0;
280 }
281}
282
283
284/* enqueue a event to singe queue */
285int snd_seq_enqueue_event(struct snd_seq_event_cell *cell, int atomic, int hop)
286{
287 int dest, err;
288 struct snd_seq_queue *q __free(snd_seq_queue) = NULL;
289
290 if (snd_BUG_ON(!cell))
291 return -EINVAL;
292 dest = cell->event.queue; /* destination queue */
293 q = queueptr(queueid: dest);
294 if (q == NULL)
295 return -EINVAL;
296 /* handle relative time stamps, convert them into absolute */
297 if ((cell->event.flags & SNDRV_SEQ_TIME_MODE_MASK) == SNDRV_SEQ_TIME_MODE_REL) {
298 switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
299 case SNDRV_SEQ_TIME_STAMP_TICK:
300 cell->event.time.tick += q->timer->tick.cur_tick;
301 break;
302
303 case SNDRV_SEQ_TIME_STAMP_REAL:
304 snd_seq_inc_real_time(tm: &cell->event.time.time,
305 inc: &q->timer->cur_time);
306 break;
307 }
308 cell->event.flags &= ~SNDRV_SEQ_TIME_MODE_MASK;
309 cell->event.flags |= SNDRV_SEQ_TIME_MODE_ABS;
310 }
311 /* enqueue event in the real-time or midi queue */
312 switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
313 case SNDRV_SEQ_TIME_STAMP_TICK:
314 err = snd_seq_prioq_cell_in(f: q->tickq, cell);
315 break;
316
317 case SNDRV_SEQ_TIME_STAMP_REAL:
318 default:
319 err = snd_seq_prioq_cell_in(f: q->timeq, cell);
320 break;
321 }
322
323 if (err < 0)
324 return err;
325
326 /* trigger dispatching */
327 snd_seq_check_queue(q, atomic, hop);
328
329 return 0;
330}
331
332
333/*----------------------------------------------------------------*/
334
335static inline int check_access(struct snd_seq_queue *q, int client)
336{
337 return (q->owner == client) || (!q->locked && !q->klocked);
338}
339
340/* check if the client has permission to modify queue parameters.
341 * if it does, lock the queue
342 */
343static int queue_access_lock(struct snd_seq_queue *q, int client)
344{
345 int access_ok;
346
347 guard(spinlock_irqsave)(l: &q->owner_lock);
348 access_ok = check_access(q, client);
349 if (access_ok)
350 q->klocked = 1;
351 return access_ok;
352}
353
354/* unlock the queue */
355static inline void queue_access_unlock(struct snd_seq_queue *q)
356{
357 guard(spinlock_irqsave)(l: &q->owner_lock);
358 q->klocked = 0;
359}
360
361/* exported - only checking permission */
362int snd_seq_queue_check_access(int queueid, int client)
363{
364 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
365
366 if (! q)
367 return 0;
368 guard(spinlock_irqsave)(l: &q->owner_lock);
369 return check_access(q, client);
370}
371
372/*----------------------------------------------------------------*/
373
374/*
375 * change queue's owner and permission
376 */
377int snd_seq_queue_set_owner(int queueid, int client, int locked)
378{
379 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
380
381 if (q == NULL)
382 return -EINVAL;
383
384 if (!queue_access_lock(q, client))
385 return -EPERM;
386
387 scoped_guard(spinlock_irqsave, &q->owner_lock) {
388 q->locked = locked ? 1 : 0;
389 q->owner = client;
390 }
391 queue_access_unlock(q);
392
393 return 0;
394}
395
396
397/*----------------------------------------------------------------*/
398
399/* open timer -
400 * q->use mutex should be down before calling this function to avoid
401 * confliction with snd_seq_queue_use()
402 */
403int snd_seq_queue_timer_open(int queueid)
404{
405 int result = 0;
406 struct snd_seq_queue *queue __free(snd_seq_queue) = NULL;
407 struct snd_seq_timer *tmr;
408
409 queue = queueptr(queueid);
410 if (queue == NULL)
411 return -EINVAL;
412 tmr = queue->timer;
413 result = snd_seq_timer_open(q: queue);
414 if (result < 0) {
415 snd_seq_timer_defaults(tmr);
416 result = snd_seq_timer_open(q: queue);
417 }
418 return result;
419}
420
421/* close timer -
422 * q->use mutex should be down before calling this function
423 */
424int snd_seq_queue_timer_close(int queueid)
425{
426 struct snd_seq_queue *queue __free(snd_seq_queue) = NULL;
427 int result = 0;
428
429 queue = queueptr(queueid);
430 if (queue == NULL)
431 return -EINVAL;
432 snd_seq_timer_close(q: queue);
433 return result;
434}
435
436/* change queue tempo and ppq */
437int snd_seq_queue_timer_set_tempo(int queueid, int client,
438 struct snd_seq_queue_tempo *info)
439{
440 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);
441 int result;
442
443 if (q == NULL)
444 return -EINVAL;
445 if (!queue_access_lock(q, client))
446 return -EPERM;
447
448 result = snd_seq_timer_set_tempo_ppq(tmr: q->timer, tempo: info->tempo, ppq: info->ppq,
449 tempo_base: info->tempo_base);
450 if (result >= 0 && info->skew_base > 0)
451 result = snd_seq_timer_set_skew(tmr: q->timer, skew: info->skew_value,
452 base: info->skew_base);
453 queue_access_unlock(q);
454 return result;
455}
456
457/* use or unuse this queue */
458static void queue_use(struct snd_seq_queue *queue, int client, int use)
459{
460 if (use) {
461 if (!test_and_set_bit(nr: client, addr: queue->clients_bitmap))
462 queue->clients++;
463 } else {
464 if (test_and_clear_bit(nr: client, addr: queue->clients_bitmap))
465 queue->clients--;
466 }
467 if (queue->clients) {
468 if (use && queue->clients == 1)
469 snd_seq_timer_defaults(tmr: queue->timer);
470 snd_seq_timer_open(q: queue);
471 } else {
472 snd_seq_timer_close(q: queue);
473 }
474}
475
476/* use or unuse this queue -
477 * if it is the first client, starts the timer.
478 * if it is not longer used by any clients, stop the timer.
479 */
480int snd_seq_queue_use(int queueid, int client, int use)
481{
482 struct snd_seq_queue *queue __free(snd_seq_queue) = NULL;
483
484 queue = queueptr(queueid);
485 if (queue == NULL)
486 return -EINVAL;
487 guard(mutex)(T: &queue->timer_mutex);
488 queue_use(queue, client, use);
489 return 0;
490}
491
492/*
493 * check if queue is used by the client
494 * return negative value if the queue is invalid.
495 * return 0 if not used, 1 if used.
496 */
497int snd_seq_queue_is_used(int queueid, int client)
498{
499 struct snd_seq_queue *q __free(snd_seq_queue) = NULL;
500
501 q = queueptr(queueid);
502 if (q == NULL)
503 return -EINVAL; /* invalid queue */
504 return test_bit(client, q->clients_bitmap) ? 1 : 0;
505}
506
507
508/*----------------------------------------------------------------*/
509
510/* final stage notification -
511 * remove cells for no longer exist client (for non-owned queue)
512 * or delete this queue (for owned queue)
513 */
514void snd_seq_queue_client_leave(int client)
515{
516 int i;
517
518 /* delete own queues from queue list */
519 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
520 struct snd_seq_queue *q = queue_list_remove(id: i, client);
521 if (q)
522 queue_delete(q);
523 }
524
525 /* remove cells from existing queues -
526 * they are not owned by this client
527 */
528 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
529 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid: i);
530 if (!q)
531 continue;
532 if (test_bit(client, q->clients_bitmap)) {
533 snd_seq_prioq_leave(f: q->tickq, client, timestamp: 0);
534 snd_seq_prioq_leave(f: q->timeq, client, timestamp: 0);
535 snd_seq_queue_use(queueid: q->queue, client, use: 0);
536 }
537 }
538}
539
540
541
542/*----------------------------------------------------------------*/
543
544/* remove cells based on flush criteria */
545void snd_seq_queue_remove_cells(int client, struct snd_seq_remove_events *info)
546{
547 int i;
548
549 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
550 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid: i);
551 if (!q)
552 continue;
553 if (test_bit(client, q->clients_bitmap) &&
554 (! (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) ||
555 q->queue == info->queue)) {
556 snd_seq_prioq_remove_events(f: q->tickq, client, info);
557 snd_seq_prioq_remove_events(f: q->timeq, client, info);
558 }
559 }
560}
561
562/*----------------------------------------------------------------*/
563
564/*
565 * send events to all subscribed ports
566 */
567static void queue_broadcast_event(struct snd_seq_queue *q, struct snd_seq_event *ev,
568 int atomic, int hop)
569{
570 struct snd_seq_event sev;
571
572 sev = *ev;
573
574 sev.flags = SNDRV_SEQ_TIME_STAMP_TICK|SNDRV_SEQ_TIME_MODE_ABS;
575 sev.time.tick = q->timer->tick.cur_tick;
576 sev.queue = q->queue;
577 sev.data.queue.queue = q->queue;
578
579 /* broadcast events from Timer port */
580 sev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
581 sev.source.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
582 sev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
583 snd_seq_kernel_client_dispatch(SNDRV_SEQ_CLIENT_SYSTEM, ev: &sev, atomic, hop);
584}
585
586/*
587 * process a received queue-control event.
588 * this function is exported for seq_sync.c.
589 */
590static void snd_seq_queue_process_event(struct snd_seq_queue *q,
591 struct snd_seq_event *ev,
592 int atomic, int hop)
593{
594 switch (ev->type) {
595 case SNDRV_SEQ_EVENT_START:
596 snd_seq_prioq_leave(f: q->tickq, client: ev->source.client, timestamp: 1);
597 snd_seq_prioq_leave(f: q->timeq, client: ev->source.client, timestamp: 1);
598 if (! snd_seq_timer_start(tmr: q->timer))
599 queue_broadcast_event(q, ev, atomic, hop);
600 break;
601
602 case SNDRV_SEQ_EVENT_CONTINUE:
603 if (! snd_seq_timer_continue(tmr: q->timer))
604 queue_broadcast_event(q, ev, atomic, hop);
605 break;
606
607 case SNDRV_SEQ_EVENT_STOP:
608 snd_seq_timer_stop(tmr: q->timer);
609 queue_broadcast_event(q, ev, atomic, hop);
610 break;
611
612 case SNDRV_SEQ_EVENT_TEMPO:
613 snd_seq_timer_set_tempo(tmr: q->timer, tempo: ev->data.queue.param.value);
614 queue_broadcast_event(q, ev, atomic, hop);
615 break;
616
617 case SNDRV_SEQ_EVENT_SETPOS_TICK:
618 if (snd_seq_timer_set_position_tick(tmr: q->timer, position: ev->data.queue.param.time.tick) == 0) {
619 queue_broadcast_event(q, ev, atomic, hop);
620 }
621 break;
622
623 case SNDRV_SEQ_EVENT_SETPOS_TIME:
624 if (snd_seq_timer_set_position_time(tmr: q->timer, position: ev->data.queue.param.time.time) == 0) {
625 queue_broadcast_event(q, ev, atomic, hop);
626 }
627 break;
628 case SNDRV_SEQ_EVENT_QUEUE_SKEW:
629 if (snd_seq_timer_set_skew(tmr: q->timer,
630 skew: ev->data.queue.param.skew.value,
631 base: ev->data.queue.param.skew.base) == 0) {
632 queue_broadcast_event(q, ev, atomic, hop);
633 }
634 break;
635 }
636}
637
638
639/*
640 * Queue control via timer control port:
641 * this function is exported as a callback of timer port.
642 */
643int snd_seq_control_queue(struct snd_seq_event *ev, int atomic, int hop)
644{
645 struct snd_seq_queue *q __free(snd_seq_queue) = NULL;
646
647 if (snd_BUG_ON(!ev))
648 return -EINVAL;
649 q = queueptr(queueid: ev->data.queue.queue);
650
651 if (q == NULL)
652 return -EINVAL;
653
654 if (!queue_access_lock(q, client: ev->source.client))
655 return -EPERM;
656
657 snd_seq_queue_process_event(q, ev, atomic, hop);
658
659 queue_access_unlock(q);
660 return 0;
661}
662
663
664/*----------------------------------------------------------------*/
665
666#ifdef CONFIG_SND_PROC_FS
667/* exported to seq_info.c */
668void snd_seq_info_queues_read(struct snd_info_entry *entry,
669 struct snd_info_buffer *buffer)
670{
671 int i, bpm;
672 struct snd_seq_timer *tmr;
673 bool locked;
674 int owner;
675
676 for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
677 struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid: i);
678 if (!q)
679 continue;
680
681 tmr = q->timer;
682 if (tmr->tempo)
683 bpm = (60000 * tmr->tempo_base) / tmr->tempo;
684 else
685 bpm = 0;
686
687 scoped_guard(spinlock_irq, &q->owner_lock) {
688 locked = q->locked;
689 owner = q->owner;
690 }
691
692 snd_iprintf(buffer, "queue %d: [%s]\n", q->queue, q->name);
693 snd_iprintf(buffer, "owned by client : %d\n", owner);
694 snd_iprintf(buffer, "lock status : %s\n", locked ? "Locked" : "Free");
695 snd_iprintf(buffer, "queued time events : %d\n", snd_seq_prioq_avail(q->timeq));
696 snd_iprintf(buffer, "queued tick events : %d\n", snd_seq_prioq_avail(q->tickq));
697 snd_iprintf(buffer, "timer state : %s\n", tmr->running ? "Running" : "Stopped");
698 snd_iprintf(buffer, "timer PPQ : %d\n", tmr->ppq);
699 snd_iprintf(buffer, "current tempo : %d\n", tmr->tempo);
700 snd_iprintf(buffer, "tempo base : %d ns\n", tmr->tempo_base);
701 snd_iprintf(buffer, "current BPM : %d\n", bpm);
702 snd_iprintf(buffer, "current time : %d.%09d s\n", tmr->cur_time.tv_sec, tmr->cur_time.tv_nsec);
703 snd_iprintf(buffer, "current tick : %d\n", tmr->tick.cur_tick);
704 snd_iprintf(buffer, "\n");
705 }
706}
707#endif /* CONFIG_SND_PROC_FS */
708
709

source code of linux/sound/core/seq/seq_queue.c