1/* 2 * linux/arch/m68k/amiga/amisound.c 3 * 4 * amiga sound driver for Linux/m68k 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file COPYING in the main directory of this archive 8 * for more details. 9 */ 10 11#include <linux/jiffies.h> 12#include <linux/timer.h> 13#include <linux/init.h> 14#include <linux/string.h> 15#include <linux/module.h> 16 17#include <asm/system.h> 18#include <asm/amigahw.h> 19 20static unsigned short *snd_data; 21static const signed char sine_data[] = { 22 0, 39, 75, 103, 121, 127, 121, 103, 75, 39, 23 0, -39, -75, -103, -121, -127, -121, -103, -75, -39 24}; 25#define DATA_SIZE ARRAY_SIZE(sine_data) 26 27#define custom amiga_custom 28 29 /* 30 * The minimum period for audio may be modified by the frame buffer 31 * device since it depends on htotal (for OCS/ECS/AGA) 32 */ 33 34volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ 35EXPORT_SYMBOL(amiga_audio_min_period); 36 37#define MAX_PERIOD (65535) 38 39 40 /* 41 * Current period (set by dmasound.c) 42 */ 43 44unsigned short amiga_audio_period = MAX_PERIOD; 45EXPORT_SYMBOL(amiga_audio_period); 46 47static unsigned long clock_constant; 48 49void __init amiga_init_sound(void) 50{ 51 static struct resource beep_res = { .name = "Beep" }; 52 53 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); 54 if (!snd_data) { 55 printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n"); 56 return; 57 } 58 memcpy (snd_data, sine_data, sizeof(sine_data)); 59 60 /* setup divisor */ 61 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; 62 63 /* without amifb, turn video off and enable high quality sound */ 64#ifndef CONFIG_FB_AMIGA 65 amifb_video_off(); 66#endif 67} 68 69static void nosound( unsigned long ignored ); 70static DEFINE_TIMER(sound_timer, nosound, 0, 0); 71 72void amiga_mksound( unsigned int hz, unsigned int ticks ) 73{ 74 unsigned long flags; 75 76 if (!snd_data) 77 return; 78 79 local_irq_save(flags); 80 del_timer( &sound_timer ); 81 82 if (hz > 20 && hz < 32767) { 83 unsigned long period = (clock_constant / hz); 84 85 if (period < amiga_audio_min_period) 86 period = amiga_audio_min_period; 87 if (period > MAX_PERIOD) 88 period = MAX_PERIOD; 89 90 /* setup pointer to data, period, length and volume */ 91 custom.aud[2].audlc = snd_data; 92 custom.aud[2].audlen = sizeof(sine_data)/2; 93 custom.aud[2].audper = (unsigned short)period; 94 custom.aud[2].audvol = 32; /* 50% of maxvol */ 95 96 if (ticks) { 97 sound_timer.expires = jiffies + ticks; 98 add_timer( &sound_timer ); 99 } 100 101 /* turn on DMA for audio channel 2 */ 102 custom.dmacon = DMAF_SETCLR | DMAF_AUD2; 103 104 } else 105 nosound( 0 ); 106 107 local_irq_restore(flags); 108} 109 110 111static void nosound( unsigned long ignored ) 112{ 113 /* turn off DMA for audio channel 2 */ 114 custom.dmacon = DMAF_AUD2; 115 /* restore period to previous value after beeping */ 116 custom.aud[2].audper = amiga_audio_period; 117} 118