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/*
* linux/arch/m68k/amiga/amisound.c
*
* amiga sound driver for Linux/m68k
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <asm/system.h>
#include <asm/amigahw.h>
static u_short *snd_data = NULL;
static const signed char sine_data[] = {
0, 39, 75, 103, 121, 127, 121, 103, 75, 39,
0, -39, -75, -103, -121, -127, -121, -103, -75, -39
};
#define DATA_SIZE (sizeof(sine_data)/sizeof(sine_data[0]))
/*
* The minimum period for audio may be modified by the frame buffer
* device since it depends on htotal (for OCS/ECS/AGA)
*/
volatile u_short amiga_audio_min_period = 124; /* Default for pre-OCS */
#define MAX_PERIOD (65535)
/*
* Current period (set by dmasound.c)
*/
u_short amiga_audio_period = MAX_PERIOD;
static u_long clock_constant;
void __init amiga_init_sound(void)
{
snd_data = amiga_chip_alloc(sizeof(sine_data));
if (!snd_data) {
printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n");
return;
}
memcpy (snd_data, sine_data, sizeof(sine_data));
/* setup divisor */
clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
}
static void nosound( unsigned long ignored );
static struct timer_list sound_timer = { NULL, NULL, 0, 0, nosound };
void amiga_mksound( unsigned int hz, unsigned int ticks )
{
unsigned long flags;
if (!snd_data)
return;
save_flags(flags);
cli();
del_timer( &sound_timer );
if (hz > 20 && hz < 32767) {
u_long period = (clock_constant / hz);
if (period < amiga_audio_min_period)
period = amiga_audio_min_period;
if (period > MAX_PERIOD)
period = MAX_PERIOD;
/* setup pointer to data, period, length and volume */
custom.aud[2].audlc = snd_data;
custom.aud[2].audlen = sizeof(sine_data)/2;
custom.aud[2].audper = (u_short)period;
custom.aud[2].audvol = 32; /* 50% of maxvol */
if (ticks) {
sound_timer.expires = jiffies + ticks;
add_timer( &sound_timer );
}
/* turn on DMA for audio channel 2 */
custom.dmacon = DMAF_SETCLR | DMAF_AUD2;
restore_flags(flags);
return;
} else {
nosound( 0 );
restore_flags(flags);
return;
}
}
static void nosound( unsigned long ignored )
{
/* turn off DMA for audio channel 2 */
custom.dmacon = DMAF_AUD2;
/* restore period to previous value after beeping */
custom.aud[2].audper = amiga_audio_period;
}
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