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/jiffies.h> 13 #include <linux/timer.h> 14 #include <linux/init.h> 15 #include <linux/string.h> 16 17 #include <asm/system.h> 18 #include <asm/amigahw.h> 19 20 static unsigned short *snd_data; 21 static 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 (sizeof(sine_data)/sizeof(sine_data[0])) 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 34 volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ 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 45 static unsigned long clock_constant; 46 47 void __init amiga_init_sound(void) 48 { 49 static struct resource beep_res = { .name = "Beep" }; 50 51 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); 52 if (!snd_data) { 53 printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n"); 54 return; 55 } 56 memcpy (snd_data, sine_data, sizeof(sine_data)); 57 58 /* setup divisor */ 59 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; 60 61 /* without amifb, turn video off and enable high quality sound */ 62 #ifndef CONFIG_FB_AMIGA 63 amifb_video_off(); 64 #endif 65 } 66 67 static void nosound( unsigned long ignored ); 68 static DEFINE_TIMER(sound_timer, nosound, 0, 0); 69 70 void amiga_mksound( unsigned int hz, unsigned int ticks ) 71 { 72 unsigned long flags; 73 74 if (!snd_data) 75 return; 76 77 local_irq_save(flags); 78 del_timer( &sound_timer ); 79 80 if (hz > 20 && hz < 32767) { 81 unsigned long period = (clock_constant / hz); 82 83 if (period < amiga_audio_min_period) 84 period = amiga_audio_min_period; 85 if (period > MAX_PERIOD) 86 period = MAX_PERIOD; 87 88 /* setup pointer to data, period, length and volume */ 89 custom.aud[2].audlc = snd_data; 90 custom.aud[2].audlen = sizeof(sine_data)/2; 91 custom.aud[2].audper = (unsigned short)period; 92 custom.aud[2].audvol = 32; /* 50% of maxvol */ 93 94 if (ticks) { 95 sound_timer.expires = jiffies + ticks; 96 add_timer( &sound_timer ); 97 } 98 99 /* turn on DMA for audio channel 2 */ 100 custom.dmacon = DMAF_SETCLR | DMAF_AUD2; 101 102 } else 103 nosound( 0 ); 104 105 local_irq_restore(flags); 106 } 107 108 109 static void nosound( unsigned long ignored ) 110 { 111 /* turn off DMA for audio channel 2 */ 112 custom.dmacon = DMAF_AUD2; 113 /* restore period to previous value after beeping */ 114 custom.aud[2].audper = amiga_audio_period; 115 } 116