seq_oss_writeq.c

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/*
 * OSS compatible sequencer driver
 *
 * seq_oss_writeq.c - write queue and sync
 *
 * Copyright (C) 1998,99 Takashi Iwai <[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
 */

#include "seq_oss_writeq.h"
#include "seq_oss_event.h"
#include "seq_oss_timer.h"
#include <sound/seq_oss_legacy.h>
#include "../seq_lock.h"
#include "../seq_clientmgr.h"
#include <linux/wait.h>
#include <linux/slab.h>


/*
 * create a write queue record
 */
struct seq_oss_writeq *
snd_seq_oss_writeq_new(struct seq_oss_devinfo *dp, int maxlen)
{
    struct seq_oss_writeq *q;
    struct snd_seq_client_pool pool;

    if ((q = kzalloc(sizeof(*q), GFP_KERNEL)) == NULL)
        return NULL;
    q->dp = dp;
    q->maxlen = maxlen;
    spin_lock_init(&q->sync_lock);
    q->sync_event_put = 0;
    q->sync_time = 0;
    init_waitqueue_head(&q->sync_sleep);

    memset(&pool, 0, sizeof(pool));
    pool.client = dp->cseq;
    pool.output_pool = maxlen;
    pool.output_room = maxlen / 2;

    snd_seq_oss_control(dp, SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, &pool);

    return q;
}

/*
 * delete the write queue
 */
void
snd_seq_oss_writeq_delete(struct seq_oss_writeq *q)
{
    if (q) {
        snd_seq_oss_writeq_clear(q);    /* to be sure */
        kfree(q);
    }
}


/*
 * reset the write queue
 */
void
snd_seq_oss_writeq_clear(struct seq_oss_writeq *q)
{
    struct snd_seq_remove_events reset;

    memset(&reset, 0, sizeof(reset));
    reset.remove_mode = SNDRV_SEQ_REMOVE_OUTPUT; /* remove all */
    snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_REMOVE_EVENTS, &reset);

    /* wake up sleepers if any */
    snd_seq_oss_writeq_wakeup(q, 0);
}

/*
 * wait until the write buffer has enough room
 */
int
snd_seq_oss_writeq_sync(struct seq_oss_writeq *q)
{
    struct seq_oss_devinfo *dp = q->dp;
    abstime_t time;

    time = snd_seq_oss_timer_cur_tick(dp->timer);
    if (q->sync_time >= time)
        return 0; /* already finished */

    if (! q->sync_event_put) {
        struct snd_seq_event ev;
        union evrec *rec;

        /* put echoback event */
        memset(&ev, 0, sizeof(ev));
        ev.flags = 0;
        ev.type = SNDRV_SEQ_EVENT_ECHO;
        ev.time.tick = time;
        /* echo back to itself */
        snd_seq_oss_fill_addr(dp, &ev, dp->addr.client, dp->addr.port);
        rec = (union evrec *)&ev.data;
        rec->t.code = SEQ_SYNCTIMER;
        rec->t.time = time;
        q->sync_event_put = 1;
        snd_seq_kernel_client_enqueue_blocking(dp->cseq, &ev, NULL, 0, 0);
    }

    wait_event_interruptible_timeout(q->sync_sleep, ! q->sync_event_put, HZ);
    if (signal_pending(current))
        /* interrupted - return 0 to finish sync */
        q->sync_event_put = 0;
    if (! q->sync_event_put || q->sync_time >= time)
        return 0;
    return 1;
}

/*
 * wake up sync - echo event was catched
 */
void
snd_seq_oss_writeq_wakeup(struct seq_oss_writeq *q, abstime_t time)
{
    unsigned long flags;

    spin_lock_irqsave(&q->sync_lock, flags);
    q->sync_time = time;
    q->sync_event_put = 0;
    if (waitqueue_active(&q->sync_sleep)) {
        wake_up(&q->sync_sleep);
    }
    spin_unlock_irqrestore(&q->sync_lock, flags);
}


/*
 * return the unused pool size
 */
int
snd_seq_oss_writeq_get_free_size(struct seq_oss_writeq *q)
{
    struct snd_seq_client_pool pool;
    pool.client = q->dp->cseq;
    snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, &pool);
    return pool.output_free;
}


/*
 * set output threshold size from ioctl
 */
void
snd_seq_oss_writeq_set_output(struct seq_oss_writeq *q, int val)
{
    struct snd_seq_client_pool pool;
    pool.client = q->dp->cseq;
    snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, &pool);
    pool.output_room = val;
    snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, &pool);
}