- 根目录:
- sound
- oss
- sound_timer.c
/*
* 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 DEFINE_SPINLOCK(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);