Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 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/jiffies.h>

#include <linux/timer.h>

#include <linux/init.h>

#include <linux/string.h>

#include <asm/system.h>

#include <asm/amigahw.h>

static unsigned short *snd_data;

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]))

#define custom amiga_custom

    /*

     * The minimum period for audio may be modified by the frame buffer

     * device since it depends on htotal (for OCS/ECS/AGA)

     */

volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */

#define MAX_PERIOD      (65535)

    /*

     *  Current period (set by dmasound.c)

     */

unsigned short amiga_audio_period = MAX_PERIOD;

static unsigned long clock_constant;

void __init amiga_init_sound(void)

{

        static struct resource beep_res = { .name = "Beep" };

        snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);

        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;

        /* without amifb, turn video off and enable high quality sound */

#ifndef CONFIG_FB_AMIGA

        amifb_video_off();

#endif

}

static void nosound( unsigned long ignored );

static DEFINE_TIMER(sound_timer, nosound, 0, 0);

void amiga_mksound( unsigned int hz, unsigned int ticks )

{

        unsigned long flags;

        if (!snd_data)

                return;

        local_irq_save(flags);

        del_timer( &sound_timer );

        if (hz > 20 && hz < 32767) {

                unsigned 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 = (unsigned 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;

        } else

                nosound( 0 );

        local_irq_restore(flags);

}

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;

}