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