/* * 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 <linux/module.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 ARRAY_SIZE(sine_data) #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 */ EXPORT_SYMBOL(amiga_audio_min_period); #define MAX_PERIOD (65535) /* * Current period (set by dmasound.c) */ unsigned short amiga_audio_period = MAX_PERIOD; EXPORT_SYMBOL(amiga_audio_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; }