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root/sound/oss/sound_timer.c

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DEFINITIONS

This source file includes following definitions.
  1. tmr2ticks
  2. reprogram_timer
  3. sound_timer_syncinterval
  4. tmr_reset
  5. timer_open
  6. timer_close
  7. timer_event
  8. timer_get_time
  9. timer_ioctl
  10. timer_arm
  11. sound_timer_interrupt
  12. sound_timer_init

/*
 * sound/oss/sound_timer.c
 */
/*
 * Copyright (C) by Hannu Savolainen 1993-1997
 *
 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
 * Version 2 (June 1991). See the "COPYING" file distributed with this software
 * for more info.
 */
/*
 * Thomas Sailer   : ioctl code reworked (vmalloc/vfree removed)
 */
#include <linux/string.h>
#include <linux/spinlock.h>

#include "sound_config.h"

static volatile int initialized, opened, tmr_running;
static volatile time_t tmr_offs, tmr_ctr;
static volatile unsigned long ticks_offs;
static volatile int curr_tempo, curr_timebase;
static volatile unsigned long curr_ticks;
static volatile unsigned long next_event_time;
static unsigned long prev_event_time;
static volatile unsigned long usecs_per_tmr;    /* Length of the current interval */

static struct sound_lowlev_timer *tmr;
static spinlock_t lock;

static unsigned long tmr2ticks(int tmr_value)
{
        /*
         *    Convert timer ticks to MIDI ticks
         */

        unsigned long tmp;
        unsigned long scale;

        tmp = tmr_value * usecs_per_tmr;        /* Convert to usecs */
        scale = (60 * 1000000) / (curr_tempo * curr_timebase);  /* usecs per MIDI tick */
        return (tmp + (scale / 2)) / scale;
}

void reprogram_timer(void)
{
        unsigned long   usecs_per_tick;

        /*
         *      The user is changing the timer rate before setting a timer
         *      slap, bad bad not allowed.
         */
         
        if(!tmr)
                return;
                
        usecs_per_tick = (60 * 1000000) / (curr_tempo * curr_timebase);

        /*
         * Don't kill the system by setting too high timer rate
         */
        if (usecs_per_tick < 2000)
                usecs_per_tick = 2000;

        usecs_per_tmr = tmr->tmr_start(tmr->dev, usecs_per_tick);
}

void sound_timer_syncinterval(unsigned int new_usecs)
{
        /*
         *    This routine is called by the hardware level if
         *      the clock frequency has changed for some reason.
         */
        tmr_offs = tmr_ctr;
        ticks_offs += tmr2ticks(tmr_ctr);
        tmr_ctr = 0;
        usecs_per_tmr = new_usecs;
}
EXPORT_SYMBOL(sound_timer_syncinterval);

static void tmr_reset(void)
{
        unsigned long   flags;

        spin_lock_irqsave(&lock,flags);
        tmr_offs = 0;
        ticks_offs = 0;
        tmr_ctr = 0;
        next_event_time = (unsigned long) -1;
        prev_event_time = 0;
        curr_ticks = 0;
        spin_unlock_irqrestore(&lock,flags);
}

static int timer_open(int dev, int mode)
{
        if (opened)
                return -EBUSY;
        tmr_reset();
        curr_tempo = 60;
        curr_timebase = 100;
        opened = 1;
        reprogram_timer();
        return 0;
}

static void timer_close(int dev)
{
        opened = tmr_running = 0;
        tmr->tmr_disable(tmr->dev);
}

static int timer_event(int dev, unsigned char *event)
{
        unsigned char cmd = event[1];
        unsigned long parm = *(int *) &event[4];

        switch (cmd)
        {
                case TMR_WAIT_REL:
                        parm += prev_event_time;
                case TMR_WAIT_ABS:
                        if (parm > 0)
                        {
                                long time;

                                if (parm <= curr_ticks) /* It's the time */
                                        return TIMER_NOT_ARMED;
                                time = parm;
                                next_event_time = prev_event_time = time;
                                return TIMER_ARMED;
                        }
                        break;

                case TMR_START:
                        tmr_reset();
                        tmr_running = 1;
                        reprogram_timer();
                        break;

                case TMR_STOP:
                        tmr_running = 0;
                        break;

                case TMR_CONTINUE:
                        tmr_running = 1;
                        reprogram_timer();
                        break;

                case TMR_TEMPO:
                        if (parm)
                        {
                                if (parm < 8)
                                        parm = 8;
                                if (parm > 250)
                                        parm = 250;
                                tmr_offs = tmr_ctr;
                                ticks_offs += tmr2ticks(tmr_ctr);
                                tmr_ctr = 0;
                                curr_tempo = parm;
                                reprogram_timer();
                        }
                        break;

                case TMR_ECHO:
                        seq_copy_to_input(event, 8);
                        break;

                default:;
        }
        return TIMER_NOT_ARMED;
}

static unsigned long timer_get_time(int dev)
{
        if (!opened)
                return 0;
        return curr_ticks;
}

static int timer_ioctl(int dev, unsigned int cmd, void __user *arg)
{
        int __user *p = arg;
        int val;

        switch (cmd) 
        {
                case SNDCTL_TMR_SOURCE:
                        val = TMR_INTERNAL;
                        break;

                case SNDCTL_TMR_START:
                        tmr_reset();
                        tmr_running = 1;
                        return 0;
                
                case SNDCTL_TMR_STOP:
                        tmr_running = 0;
                        return 0;

                case SNDCTL_TMR_CONTINUE:
                        tmr_running = 1;
                        return 0;

                case SNDCTL_TMR_TIMEBASE:
                        if (get_user(val, p))
                                return -EFAULT;
                        if (val) 
                        {
                                if (val < 1)
                                        val = 1;
                                if (val > 1000)
                                        val = 1000;
                                curr_timebase = val;
                        }
                        val = curr_timebase;
                        break;

                case SNDCTL_TMR_TEMPO:
                        if (get_user(val, p))
                                return -EFAULT;
                        if (val) 
                        {
                                if (val < 8)
                                        val = 8;
                                if (val > 250)
                                        val = 250;
                                tmr_offs = tmr_ctr;
                                ticks_offs += tmr2ticks(tmr_ctr);
                                tmr_ctr = 0;
                                curr_tempo = val;
                                reprogram_timer();
                        }
                        val = curr_tempo;
                        break;

                case SNDCTL_SEQ_CTRLRATE:
                        if (get_user(val, p))
                                return -EFAULT;
                        if (val != 0)   /* Can't change */
                                return -EINVAL;
                        val = ((curr_tempo * curr_timebase) + 30) / 60;
                        break;
                
                case SNDCTL_SEQ_GETTIME:
                        val = curr_ticks;
                        break;
                
                case SNDCTL_TMR_METRONOME:
                default:
                        return -EINVAL;
        }
        return put_user(val, p);
}

static void timer_arm(int dev, long time)
{
        if (time < 0)
                time = curr_ticks + 1;
        else if (time <= curr_ticks)    /* It's the time */
                return;

        next_event_time = prev_event_time = time;
        return;
}

static struct sound_timer_operations sound_timer =
{
        .owner          = THIS_MODULE,
        .info           = {"Sound Timer", 0},
        .priority       = 1,    /* Priority */
        .devlink        = 0,    /* Local device link */
        .open           = timer_open,
        .close          = timer_close,
        .event          = timer_event,
        .get_time       = timer_get_time,
        .ioctl          = timer_ioctl,
        .arm_timer      = timer_arm
};

void sound_timer_interrupt(void)
{
        unsigned long flags;
        
        if (!opened)
                return;

        tmr->tmr_restart(tmr->dev);

        if (!tmr_running)
                return;

        spin_lock_irqsave(&lock,flags);
        tmr_ctr++;
        curr_ticks = ticks_offs + tmr2ticks(tmr_ctr);

        if (curr_ticks >= next_event_time)
        {
                next_event_time = (unsigned long) -1;
                sequencer_timer(0);
        }
        spin_unlock_irqrestore(&lock,flags);
}
EXPORT_SYMBOL(sound_timer_interrupt);

void  sound_timer_init(struct sound_lowlev_timer *t, char *name)
{
        int n;

        if (initialized)
        {
                if (t->priority <= tmr->priority)
                        return; /* There is already a similar or better timer */
                tmr = t;
                return;
        }
        initialized = 1;
        tmr = t;

        n = sound_alloc_timerdev();
        if (n == -1)
                n = 0;          /* Overwrite the system timer */
        strcpy(sound_timer.info.name, name);
        sound_timer_devs[n] = &sound_timer;
}
EXPORT_SYMBOL(sound_timer_init);


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