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