// SPDX-License-Identifier: GPL-2.0-or-later/* *   ALSA sequencer Timing queue handling *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl> * * MAJOR CHANGES *   Nov. 13, 1999	Takashi Iwai <iwai@ww.uni-erlangen.de> *     - Queues are allocated dynamically via ioctl. *     - When owner client is deleted, all owned queues are deleted, too. *     - Owner of unlocked queue is kept unmodified even if it is *	 manipulated by other clients. *     - Owner field in SET_QUEUE_OWNER ioctl must be identical with the *       caller client.  i.e. Changing owner to a third client is not *       allowed. * *  Aug. 30, 2000	Takashi Iwai *     - Queues are managed in static array again, but with better way. *       The API itself is identical. *     - The queue is locked when struct snd_seq_queue pointer is returned via *       queueptr().  This pointer *MUST* be released afterward by *       queuefree(ptr). *     - Addition of experimental sync support. */ #include <linux/init.h>#include <linux/slab.h>#include <sound/core.h> #include "seq_memory.h"#include "seq_queue.h"#include "seq_clientmgr.h"#include "seq_fifo.h"#include "seq_timer.h"#include "seq_info.h" /* list of allocated queues */static struct snd_seq_queue *queue_list[SNDRV_SEQ_MAX_QUEUES];static DEFINE_SPINLOCK(queue_list_lock);/* number of queues allocated */static int num_queues; int snd_seq_queue_get_cur_queues(void){	return num_queues;} /*----------------------------------------------------------------*/ /* assign queue id and insert to list */static int queue_list_add(struct snd_seq_queue *q){	int i; 	guard(spinlock_irqsave)(&queue_list_lock);	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {		if (! queue_list[i]) {			queue_list[i] = q;			q->queue = i;			num_queues++;			return i;		}	}	return -1;} static struct snd_seq_queue *queue_list_remove(int id, int client){	struct snd_seq_queue *q; 	guard(spinlock_irqsave)(&queue_list_lock);	q = queue_list[id];	if (q) {		guard(spinlock)(&q->owner_lock);		if (q->owner == client) {			/* found */			q->klocked = 1;			queue_list[id] = NULL;			num_queues--;			return q;		}	}	return NULL;} /*----------------------------------------------------------------*/ /* create new queue (constructor) */static struct snd_seq_queue *queue_new(int owner, int locked){	struct snd_seq_queue *q; 	q = kzalloc_obj(*q);	if (!q)		return NULL; 	spin_lock_init(&q->owner_lock);	spin_lock_init(&q->check_lock);	mutex_init(&q->timer_mutex);	snd_use_lock_init(&q->use_lock);	q->queue = -1; 	q->tickq = snd_seq_prioq_new();	q->timeq = snd_seq_prioq_new();	q->timer = snd_seq_timer_new();	if (q->tickq == NULL || q->timeq == NULL || q->timer == NULL) {		snd_seq_prioq_delete(&q->tickq);		snd_seq_prioq_delete(&q->timeq);		snd_seq_timer_delete(&q->timer);		kfree(q);		return NULL;	} 	q->owner = owner;	q->locked = locked;	q->klocked = 0; 	return q;} /* delete queue (destructor) */static void queue_delete(struct snd_seq_queue *q){	/* stop and release the timer */	mutex_lock(&q->timer_mutex);	snd_seq_timer_stop(q->timer);	snd_seq_timer_close(q);	mutex_unlock(&q->timer_mutex);	/* wait until access free */	snd_use_lock_sync(&q->use_lock);	/* release resources... */	snd_seq_prioq_delete(&q->tickq);	snd_seq_prioq_delete(&q->timeq);	snd_seq_timer_delete(&q->timer); 	kfree(q);}  /*----------------------------------------------------------------*/ /* delete all existing queues */void snd_seq_queues_delete(void){	int i; 	/* clear list */	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {		if (queue_list[i])			queue_delete(queue_list[i]);	}} static void queue_use(struct snd_seq_queue *queue, int client, int use); /* allocate a new queue - * return pointer to new queue or ERR_PTR(-errno) for error * The new queue's use_lock is set to 1. It is the caller's responsibility to * call snd_use_lock_free(&q->use_lock). */struct snd_seq_queue *snd_seq_queue_alloc(int client, int locked, unsigned int info_flags){	struct snd_seq_queue *q; 	q = queue_new(client, locked);	if (q == NULL)		return ERR_PTR(-ENOMEM);	q->info_flags = info_flags;	queue_use(q, client, 1);	snd_use_lock_use(&q->use_lock);	if (queue_list_add(q) < 0) {		snd_use_lock_free(&q->use_lock);		queue_delete(q);		return ERR_PTR(-ENOMEM);	}	return q;} /* delete a queue - queue must be owned by the client */int snd_seq_queue_delete(int client, int queueid){	struct snd_seq_queue *q; 	if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)		return -EINVAL;	q = queue_list_remove(queueid, client);	if (q == NULL)		return -EINVAL;	queue_delete(q); 	return 0;}  /* return pointer to queue structure for specified id */struct snd_seq_queue *queueptr(int queueid){	struct snd_seq_queue *q; 	if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)		return NULL;	guard(spinlock_irqsave)(&queue_list_lock);	q = queue_list[queueid];	if (q)		snd_use_lock_use(&q->use_lock);	return q;} /* return the (first) queue matching with the specified name */struct snd_seq_queue *snd_seq_queue_find_name(char *name){	int i; 	for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {		struct snd_seq_queue *q __free(snd_seq_queue) =			queueptr(i); 		if (q) {			if (strncmp(q->name, name, sizeof(q->name)) == 0)				return no_free_ptr(q);		}	}	return NULL;}  /* -------------------------------------------------------- */ #define MAX_CELL_PROCESSES_IN_QUEUE	1000 void snd_seq_check_queue(struct snd_seq_queue *q, int atomic, int hop){	struct snd_seq_event_cell *cell;	snd_seq_tick_time_t cur_tick;	snd_seq_real_time_t cur_time;	int processed = 0; 	if (q == NULL)		return; 	/* make this function non-reentrant */	scoped_guard(spinlock_irqsave, &q->check_lock) {		if (q->check_blocked) {			q->check_again = 1;			return;	/* other thread is already checking queues */		}		q->check_blocked = 1;	}       __again:	/* Process tick queue... */	cur_tick = snd_seq_timer_get_cur_tick(q->timer);	for (;;) {		cell = snd_seq_prioq_cell_out(q->tickq, &cur_tick);		if (!cell)			break;		snd_seq_dispatch_event(cell, atomic, hop);		if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)			goto out; /* the rest processed at the next batch */	} 	/* Process time queue... */	cur_time = snd_seq_timer_get_cur_time(q->timer, false);	for (;;) {		cell = snd_seq_prioq_cell_out(q->timeq, &cur_time);		if (!cell)			break;		snd_seq_dispatch_event(cell, atomic, hop);		if (++processed >= MAX_CELL_PROCESSES_IN_QUEUE)			goto out; /* the rest processed at the next batch */	}  out:	/* free lock */	scoped_guard(spinlock_irqsave, &q->check_lock) {		if (q->check_again) {			q->check_again = 0;			if (processed < MAX_CELL_PROCESSES_IN_QUEUE)				goto __again;		}		q->check_blocked = 0;	}}  /* enqueue a event to singe queue */int snd_seq_enqueue_event(struct snd_seq_event_cell *cell, int atomic, int hop){	int dest, err; 	if (snd_BUG_ON(!cell))		return -EINVAL;	dest = cell->event.queue;	/* destination queue */ 	struct snd_seq_queue *q __free(snd_seq_queue) =		queueptr(dest);	if (q == NULL)		return -EINVAL;	/* handle relative time stamps, convert them into absolute */	if ((cell->event.flags & SNDRV_SEQ_TIME_MODE_MASK) == SNDRV_SEQ_TIME_MODE_REL) {		switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {		case SNDRV_SEQ_TIME_STAMP_TICK:			cell->event.time.tick += q->timer->tick.cur_tick;			break; 		case SNDRV_SEQ_TIME_STAMP_REAL:			snd_seq_inc_real_time(&cell->event.time.time,					      &q->timer->cur_time);			break;		}		cell->event.flags &= ~SNDRV_SEQ_TIME_MODE_MASK;		cell->event.flags |= SNDRV_SEQ_TIME_MODE_ABS;	}	/* enqueue event in the real-time or midi queue */	switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {	case SNDRV_SEQ_TIME_STAMP_TICK:		err = snd_seq_prioq_cell_in(q->tickq, cell);		break; 	case SNDRV_SEQ_TIME_STAMP_REAL:	default:		err = snd_seq_prioq_cell_in(q->timeq, cell);		break;	} 	if (err < 0)		return err; 	/* trigger dispatching */	snd_seq_check_queue(q, atomic, hop); 	return 0;}  /*----------------------------------------------------------------*/ static inline int check_access(struct snd_seq_queue *q, int client){	return (q->owner == client) || (!q->locked && !q->klocked);} /* check if the client has permission to modify queue parameters. * if it does, lock the queue */static int queue_access_lock(struct snd_seq_queue *q, int client){	int access_ok;		guard(spinlock_irqsave)(&q->owner_lock);	access_ok = check_access(q, client);	if (access_ok)		q->klocked = 1;	return access_ok;} /* unlock the queue */static inline void queue_access_unlock(struct snd_seq_queue *q){	guard(spinlock_irqsave)(&q->owner_lock);	q->klocked = 0;} /* exported - only checking permission */int snd_seq_queue_check_access(int queueid, int client){	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid); 	if (! q)		return 0;	guard(spinlock_irqsave)(&q->owner_lock);	return check_access(q, client);} /*----------------------------------------------------------------*/ /* * change queue's owner and permission */int snd_seq_queue_set_owner(int queueid, int client, int locked){	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid); 	if (q == NULL)		return -EINVAL; 	if (!queue_access_lock(q, client))		return -EPERM; 	scoped_guard(spinlock_irqsave, &q->owner_lock) {		q->locked = locked ? 1 : 0;		q->owner = client;	}	queue_access_unlock(q); 	return 0;}  /*----------------------------------------------------------------*/ /* open timer - * q->use mutex should be down before calling this function to avoid * confliction with snd_seq_queue_use() */int snd_seq_queue_timer_open(int queueid){	int result = 0;	struct snd_seq_timer *tmr;	struct snd_seq_queue *queue __free(snd_seq_queue) =		queueptr(queueid); 	if (queue == NULL)		return -EINVAL;	tmr = queue->timer;	result = snd_seq_timer_open(queue);	if (result < 0) {		snd_seq_timer_defaults(tmr);		result = snd_seq_timer_open(queue);	}	return result;} /* close timer - * q->use mutex should be down before calling this function */int snd_seq_queue_timer_close(int queueid){	int result = 0;	struct snd_seq_queue *queue __free(snd_seq_queue) =		queueptr(queueid); 	if (queue == NULL)		return -EINVAL;	snd_seq_timer_close(queue);	return result;} /* change queue tempo and ppq */int snd_seq_queue_timer_set_tempo(int queueid, int client,				  struct snd_seq_queue_tempo *info){	struct snd_seq_queue *q __free(snd_seq_queue) = queueptr(queueid);	int result; 	if (q == NULL)		return -EINVAL;	if (!queue_access_lock(q, client))		return -EPERM; 	result = snd_seq_timer_set_tempo_ppq(q->timer, info->tempo, info->ppq,					     info->tempo_base);	if (result >= 0 && info->skew_base > 0)		result = snd_seq_timer_set_skew(q->timer, info->skew_value,						info->skew_base);	queue_access_unlock(q);	return result;} /* use or unuse this queue */static void queue_use(struct snd_seq_queue *queue, int client, int use){	if (use) {		if (!test_and_set_bit(client, queue->clients_bitmap))			queue->clients++;	} else {		if (test_and_clear_bit(client, queue->clients_bitmap))			queue->clients--;	}	if (queue->clients) {		if (use && queue->clients == 1)			snd_seq_timer_defaults(queue->timer);		snd_seq_timer_open(queue);	} else {		snd_seq_timer_close(queue);	}} /* use or unuse this queue - * if it is the first client, starts the timer. * if it is not longer used by any clients, stop the timer. */int snd_seq_queue_use(int queueid, int client, int use){	struct snd_seq_queue *queue __free(snd_seq_queue) =		queueptr(queueid); 	if (queue == NULL)		return -EINVAL;	guard(mutex)(&queue->timer_mutex);	queue_use(queue, client, use);	return 0;} /* * check if queue is used by the client * return negative value if the queue is invalid. * return 0 if not used, 1 if used. */int snd_seq_queue_is_used(int queueid, int client){

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