seq_queue.c

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/*
 *   ALSA sequencer Timing queue handling
 *   Copyright (c) 1998-1999 by Frank van de Pol <[email protected]>
 *
 *   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
 *
 * MAJOR CHANGES
 *   Nov. 13, 1999  Takashi Iwai <[email protected]>
 *     - 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;
    unsigned long flags;

    spin_lock_irqsave(&queue_list_lock, flags);
    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if (! queue_list[i]) {
            queue_list[i] = q;
            q->queue = i;
            num_queues++;
            spin_unlock_irqrestore(&queue_list_lock, flags);
            return i;
        }
    }
    spin_unlock_irqrestore(&queue_list_lock, flags);
    return -1;
}

static struct snd_seq_queue *queue_list_remove(int id, int client)
{
    struct snd_seq_queue *q;
    unsigned long flags;

    spin_lock_irqsave(&queue_list_lock, flags);
    q = queue_list[id];
    if (q) {
        spin_lock(&q->owner_lock);
        if (q->owner == client) {
            /* found */
            q->klocked = 1;
            spin_unlock(&q->owner_lock);
            queue_list[id] = NULL;
            num_queues--;
            spin_unlock_irqrestore(&queue_list_lock, flags);
            return q;
        }
        spin_unlock(&q->owner_lock);
    }
    spin_unlock_irqrestore(&queue_list_lock, flags);
    return NULL;
}

/*----------------------------------------------------------------*/

/* create new queue (constructor) */
static struct snd_seq_queue *queue_new(int owner, int locked)
{
    struct snd_seq_queue *q;

    q = kzalloc(sizeof(*q), GFP_KERNEL);
    if (q == NULL) {
        snd_printd("malloc failed for snd_seq_queue_new()\n");
        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 */
    snd_seq_timer_stop(q->timer);
    snd_seq_timer_close(q);
    /* 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);
}


/*----------------------------------------------------------------*/

/* setup queues */
int __init snd_seq_queues_init(void)
{
    /*
    memset(queue_list, 0, sizeof(queue_list));
    num_queues = 0;
    */
    return 0;
}

/* delete all existing queues */
void __exit 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]);
    }
}

/* allocate a new queue -
 * return queue index value or negative value for error
 */
int 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 -ENOMEM;
    q->info_flags = info_flags;
    if (queue_list_add(q) < 0) {
        queue_delete(q);
        return -ENOMEM;
    }
    snd_seq_queue_use(q->queue, client, 1); /* use this queue */
    return q->queue;
}

/* 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;
    unsigned long flags;

    if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
        return NULL;
    spin_lock_irqsave(&queue_list_lock, flags);
    q = queue_list[queueid];
    if (q)
        snd_use_lock_use(&q->use_lock);
    spin_unlock_irqrestore(&queue_list_lock, flags);
    return q;
}

/* return the (first) queue matching with the specified name */
struct snd_seq_queue *snd_seq_queue_find_name(char *name)
{
    int i;
    struct snd_seq_queue *q;

    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) != NULL) {
            if (strncmp(q->name, name, sizeof(q->name)) == 0)
                return q;
            queuefree(q);
        }
    }
    return NULL;
}


/* -------------------------------------------------------- */

void snd_seq_check_queue(struct snd_seq_queue *q, int atomic, int hop)
{
    unsigned long flags;
    struct snd_seq_event_cell *cell;

    if (q == NULL)
        return;

    /* make this function non-reentrant */
    spin_lock_irqsave(&q->check_lock, flags);
    if (q->check_blocked) {
        q->check_again = 1;
        spin_unlock_irqrestore(&q->check_lock, flags);
        return;     /* other thread is already checking queues */
    }
    q->check_blocked = 1;
    spin_unlock_irqrestore(&q->check_lock, flags);

      __again:
    /* Process tick queue... */
    while ((cell = snd_seq_prioq_cell_peek(q->tickq)) != NULL) {
        if (snd_seq_compare_tick_time(&q->timer->tick.cur_tick,
                          &cell->event.time.tick)) {
            cell = snd_seq_prioq_cell_out(q->tickq);
            if (cell)
                snd_seq_dispatch_event(cell, atomic, hop);
        } else {
            /* event remains in the queue */
            break;
        }
    }


    /* Process time queue... */
    while ((cell = snd_seq_prioq_cell_peek(q->timeq)) != NULL) {
        if (snd_seq_compare_real_time(&q->timer->cur_time,
                          &cell->event.time.time)) {
            cell = snd_seq_prioq_cell_out(q->timeq);
            if (cell)
                snd_seq_dispatch_event(cell, atomic, hop);
        } else {
            /* event remains in the queue */
            break;
        }
    }

    /* free lock */
    spin_lock_irqsave(&q->check_lock, flags);
    if (q->check_again) {
        q->check_again = 0;
        spin_unlock_irqrestore(&q->check_lock, flags);
        goto __again;
    }
    q->check_blocked = 0;
    spin_unlock_irqrestore(&q->check_lock, flags);
}


/* enqueue a event to singe queue */
int snd_seq_enqueue_event(struct snd_seq_event_cell *cell, int atomic, int hop)
{
    int dest, err;
    struct snd_seq_queue *q;

    if (snd_BUG_ON(!cell))
        return -EINVAL;
    dest = cell->event.queue;   /* destination queue */
    q = 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) {
        queuefree(q); /* unlock */
        return err;
    }

    /* trigger dispatching */
    snd_seq_check_queue(q, atomic, hop);

    queuefree(q); /* unlock */

    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)
{
    unsigned long flags;
    int access_ok;
    
    spin_lock_irqsave(&q->owner_lock, flags);
    access_ok = check_access(q, client);
    if (access_ok)
        q->klocked = 1;
    spin_unlock_irqrestore(&q->owner_lock, flags);
    return access_ok;
}

/* unlock the queue */
static inline void queue_access_unlock(struct snd_seq_queue *q)
{
    unsigned long flags;

    spin_lock_irqsave(&q->owner_lock, flags);
    q->klocked = 0;
    spin_unlock_irqrestore(&q->owner_lock, flags);
}

/* exported - only checking permission */
int snd_seq_queue_check_access(int queueid, int client)
{
    struct snd_seq_queue *q = queueptr(queueid);
    int access_ok;
    unsigned long flags;

    if (! q)
        return 0;
    spin_lock_irqsave(&q->owner_lock, flags);
    access_ok = check_access(q, client);
    spin_unlock_irqrestore(&q->owner_lock, flags);
    queuefree(q);
    return access_ok;
}

/*----------------------------------------------------------------*/

/*
 * change queue's owner and permission
 */
int snd_seq_queue_set_owner(int queueid, int client, int locked)
{
    struct snd_seq_queue *q = queueptr(queueid);

    if (q == NULL)
        return -EINVAL;

    if (! queue_access_lock(q, client)) {
        queuefree(q);
        return -EPERM;
    }

    q->locked = locked ? 1 : 0;
    q->owner = client;
    queue_access_unlock(q);
    queuefree(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_queue *queue;
    struct snd_seq_timer *tmr;

    queue = queueptr(queueid);
    if (queue == NULL)
        return -EINVAL;
    tmr = queue->timer;
    if ((result = snd_seq_timer_open(queue)) < 0) {
        snd_seq_timer_defaults(tmr);
        result = snd_seq_timer_open(queue);
    }
    queuefree(queue);
    return result;
}

/* close timer -
 * q->use mutex should be down before calling this function
 */
int snd_seq_queue_timer_close(int queueid)
{
    struct snd_seq_queue *queue;
    int result = 0;

    queue = queueptr(queueid);
    if (queue == NULL)
        return -EINVAL;
    snd_seq_timer_close(queue);
    queuefree(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 = queueptr(queueid);
    int result;

    if (q == NULL)
        return -EINVAL;
    if (! queue_access_lock(q, client)) {
        queuefree(q);
        return -EPERM;
    }

    result = snd_seq_timer_set_tempo(q->timer, info->tempo);
    if (result >= 0)
        result = snd_seq_timer_set_ppq(q->timer, info->ppq);
    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);
    queuefree(q);
    return result;
}


/* 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;

    queue = queueptr(queueid);
    if (queue == NULL)
        return -EINVAL;
    mutex_lock(&queue->timer_mutex);
    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);
    }
    mutex_unlock(&queue->timer_mutex);
    queuefree(queue);
    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)
{
    struct snd_seq_queue *q;
    int result;

    q = queueptr(queueid);
    if (q == NULL)
        return -EINVAL; /* invalid queue */
    result = test_bit(client, q->clients_bitmap) ? 1 : 0;
    queuefree(q);
    return result;
}


/*----------------------------------------------------------------*/

/* notification that client has left the system -
 * stop the timer on all queues owned by this client
 */
void snd_seq_queue_client_termination(int client)
{
    unsigned long flags;
    int i;
    struct snd_seq_queue *q;

    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) == NULL)
            continue;
        spin_lock_irqsave(&q->owner_lock, flags);
        if (q->owner == client)
            q->klocked = 1;
        spin_unlock_irqrestore(&q->owner_lock, flags);
        if (q->owner == client) {
            if (q->timer->running)
                snd_seq_timer_stop(q->timer);
            snd_seq_timer_reset(q->timer);
        }
        queuefree(q);
    }
}

/* final stage notification -
 * remove cells for no longer exist client (for non-owned queue)
 * or delete this queue (for owned queue)
 */
void snd_seq_queue_client_leave(int client)
{
    int i;
    struct snd_seq_queue *q;

    /* delete own queues from queue list */
    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queue_list_remove(i, client)) != NULL)
            queue_delete(q);
    }

    /* remove cells from existing queues -
     * they are not owned by this client
     */
    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) == NULL)
            continue;
        if (test_bit(client, q->clients_bitmap)) {
            snd_seq_prioq_leave(q->tickq, client, 0);
            snd_seq_prioq_leave(q->timeq, client, 0);
            snd_seq_queue_use(q->queue, client, 0);
        }
        queuefree(q);
    }
}



/*----------------------------------------------------------------*/

/* remove cells from all queues */
void snd_seq_queue_client_leave_cells(int client)
{
    int i;
    struct snd_seq_queue *q;

    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) == NULL)
            continue;
        snd_seq_prioq_leave(q->tickq, client, 0);
        snd_seq_prioq_leave(q->timeq, client, 0);
        queuefree(q);
    }
}

/* remove cells based on flush criteria */
void snd_seq_queue_remove_cells(int client, struct snd_seq_remove_events *info)
{
    int i;
    struct snd_seq_queue *q;

    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) == NULL)
            continue;
        if (test_bit(client, q->clients_bitmap) &&
            (! (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) ||
             q->queue == info->queue)) {
            snd_seq_prioq_remove_events(q->tickq, client, info);
            snd_seq_prioq_remove_events(q->timeq, client, info);
        }
        queuefree(q);
    }
}

/*----------------------------------------------------------------*/

/*
 * send events to all subscribed ports
 */
static void queue_broadcast_event(struct snd_seq_queue *q, struct snd_seq_event *ev,
                  int atomic, int hop)
{
    struct snd_seq_event sev;

    sev = *ev;
    
    sev.flags = SNDRV_SEQ_TIME_STAMP_TICK|SNDRV_SEQ_TIME_MODE_ABS;
    sev.time.tick = q->timer->tick.cur_tick;
    sev.queue = q->queue;
    sev.data.queue.queue = q->queue;

    /* broadcast events from Timer port */
    sev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
    sev.source.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
    sev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
    snd_seq_kernel_client_dispatch(SNDRV_SEQ_CLIENT_SYSTEM, &sev, atomic, hop);
}

/*
 * process a received queue-control event.
 * this function is exported for seq_sync.c.
 */
static void snd_seq_queue_process_event(struct snd_seq_queue *q,
                    struct snd_seq_event *ev,
                    int atomic, int hop)
{
    switch (ev->type) {
    case SNDRV_SEQ_EVENT_START:
        snd_seq_prioq_leave(q->tickq, ev->source.client, 1);
        snd_seq_prioq_leave(q->timeq, ev->source.client, 1);
        if (! snd_seq_timer_start(q->timer))
            queue_broadcast_event(q, ev, atomic, hop);
        break;

    case SNDRV_SEQ_EVENT_CONTINUE:
        if (! snd_seq_timer_continue(q->timer))
            queue_broadcast_event(q, ev, atomic, hop);
        break;

    case SNDRV_SEQ_EVENT_STOP:
        snd_seq_timer_stop(q->timer);
        queue_broadcast_event(q, ev, atomic, hop);
        break;

    case SNDRV_SEQ_EVENT_TEMPO:
        snd_seq_timer_set_tempo(q->timer, ev->data.queue.param.value);
        queue_broadcast_event(q, ev, atomic, hop);
        break;

    case SNDRV_SEQ_EVENT_SETPOS_TICK:
        if (snd_seq_timer_set_position_tick(q->timer, ev->data.queue.param.time.tick) == 0) {
            queue_broadcast_event(q, ev, atomic, hop);
        }
        break;

    case SNDRV_SEQ_EVENT_SETPOS_TIME:
        if (snd_seq_timer_set_position_time(q->timer, ev->data.queue.param.time.time) == 0) {
            queue_broadcast_event(q, ev, atomic, hop);
        }
        break;
    case SNDRV_SEQ_EVENT_QUEUE_SKEW:
        if (snd_seq_timer_set_skew(q->timer,
                       ev->data.queue.param.skew.value,
                       ev->data.queue.param.skew.base) == 0) {
            queue_broadcast_event(q, ev, atomic, hop);
        }
        break;
    }
}


/*
 * Queue control via timer control port:
 * this function is exported as a callback of timer port.
 */
int snd_seq_control_queue(struct snd_seq_event *ev, int atomic, int hop)
{
    struct snd_seq_queue *q;

    if (snd_BUG_ON(!ev))
        return -EINVAL;
    q = queueptr(ev->data.queue.queue);

    if (q == NULL)
        return -EINVAL;

    if (! queue_access_lock(q, ev->source.client)) {
        queuefree(q);
        return -EPERM;
    }

    snd_seq_queue_process_event(q, ev, atomic, hop);

    queue_access_unlock(q);
    queuefree(q);
    return 0;
}


/*----------------------------------------------------------------*/

#ifdef CONFIG_PROC_FS
/* exported to seq_info.c */
void snd_seq_info_queues_read(struct snd_info_entry *entry, 
                  struct snd_info_buffer *buffer)
{
    int i, bpm;
    struct snd_seq_queue *q;
    struct snd_seq_timer *tmr;

    for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
        if ((q = queueptr(i)) == NULL)
            continue;

        tmr = q->timer;
        if (tmr->tempo)
            bpm = 60000000 / tmr->tempo;
        else
            bpm = 0;

        snd_iprintf(buffer, "queue %d: [%s]\n", q->queue, q->name);
        snd_iprintf(buffer, "owned by client    : %d\n", q->owner);
        snd_iprintf(buffer, "lock status        : %s\n", q->locked ? "Locked" : "Free");
        snd_iprintf(buffer, "queued time events : %d\n", snd_seq_prioq_avail(q->timeq));
        snd_iprintf(buffer, "queued tick events : %d\n", snd_seq_prioq_avail(q->tickq));
        snd_iprintf(buffer, "timer state        : %s\n", tmr->running ? "Running" : "Stopped");
        snd_iprintf(buffer, "timer PPQ          : %d\n", tmr->ppq);
        snd_iprintf(buffer, "current tempo      : %d\n", tmr->tempo);
        snd_iprintf(buffer, "current BPM        : %d\n", bpm);
        snd_iprintf(buffer, "current time       : %d.%09d s\n", tmr->cur_time.tv_sec, tmr->cur_time.tv_nsec);
        snd_iprintf(buffer, "current tick       : %d\n", tmr->tick.cur_tick);
        snd_iprintf(buffer, "\n");
        queuefree(q);
    }
}
#endif /* CONFIG_PROC_FS */