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 /* 28 * The minimum period for audio may be modified by the frame buffer 29 * device since it depends on htotal (for OCS/ECS/AGA) 30 */ 31 32 volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ 33 34 #define MAX_PERIOD (65535) 35 36 37 /* 38 * Current period (set by dmasound.c) 39 */ 40 41 unsigned short amiga_audio_period = MAX_PERIOD; 42 43 static unsigned long clock_constant; 44 45 void __init amiga_init_sound(void) 46 { 47 static struct resource beep_res = { .name = "Beep" }; 48 49 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); 50 if (!snd_data) { 51 printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n"); 52 return; 53 } 54 memcpy (snd_data, sine_data, sizeof(sine_data)); 55 56 /* setup divisor */ 57 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; 58 59 /* without amifb, turn video off and enable high quality sound */ 60 #ifndef CONFIG_FB_AMIGA 61 amifb_video_off(); 62 #endif 63 } 64 65 static void nosound( unsigned long ignored ); 66 static DEFINE_TIMER(sound_timer, nosound, 0, 0); 67 68 void amiga_mksound( unsigned int hz, unsigned int ticks ) 69 { 70 unsigned long flags; 71 72 if (!snd_data) 73 return; 74 75 local_irq_save(flags); 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 local_irq_restore(flags); 104 } 105 106 107 static 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