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