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 #include "amiga.h" 20 21 static unsigned short *snd_data; 22 static const signed char sine_data[] = { 23 0, 39, 75, 103, 121, 127, 121, 103, 75, 39, 24 0, -39, -75, -103, -121, -127, -121, -103, -75, -39 25 }; 26 #define DATA_SIZE ARRAY_SIZE(sine_data) 27 28 #define custom amiga_custom 29 30 /* 31 * The minimum period for audio may be modified by the frame buffer 32 * device since it depends on htotal (for OCS/ECS/AGA) 33 */ 34 35 volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ 36 EXPORT_SYMBOL(amiga_audio_min_period); 37 38 #define MAX_PERIOD (65535) 39 40 41 /* 42 * Current period (set by dmasound.c) 43 */ 44 45 unsigned short amiga_audio_period = MAX_PERIOD; 46 EXPORT_SYMBOL(amiga_audio_period); 47 48 static unsigned long clock_constant; 49 50 void __init amiga_init_sound(void) 51 { 52 static struct resource beep_res = { .name = "Beep" }; 53 54 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); 55 if (!snd_data) { 56 pr_crit("amiga init_sound: failed to allocate chipmem\n"); 57 return; 58 } 59 memcpy (snd_data, sine_data, sizeof(sine_data)); 60 61 /* setup divisor */ 62 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; 63 64 /* without amifb, turn video off and enable high quality sound */ 65 #ifndef CONFIG_FB_AMIGA 66 amifb_video_off(); 67 #endif 68 } 69 70 static void nosound(struct timer_list *unused); 71 static DEFINE_TIMER(sound_timer, nosound); 72 73 void amiga_mksound( unsigned int hz, unsigned int ticks ) 74 { 75 unsigned long flags; 76 77 if (!snd_data) 78 return; 79 80 local_irq_save(flags); 81 del_timer( &sound_timer ); 82 83 if (hz > 20 && hz < 32767) { 84 unsigned long period = (clock_constant / hz); 85 86 if (period < amiga_audio_min_period) 87 period = amiga_audio_min_period; 88 if (period > MAX_PERIOD) 89 period = MAX_PERIOD; 90 91 /* setup pointer to data, period, length and volume */ 92 custom.aud[2].audlc = snd_data; 93 custom.aud[2].audlen = sizeof(sine_data)/2; 94 custom.aud[2].audper = (unsigned short)period; 95 custom.aud[2].audvol = 32; /* 50% of maxvol */ 96 97 if (ticks) { 98 sound_timer.expires = jiffies + ticks; 99 add_timer( &sound_timer ); 100 } 101 102 /* turn on DMA for audio channel 2 */ 103 custom.dmacon = DMAF_SETCLR | DMAF_AUD2; 104 105 } else 106 nosound( 0 ); 107 108 local_irq_restore(flags); 109 } 110 111 112 static void nosound(struct timer_list *unused) 113 { 114 /* turn off DMA for audio channel 2 */ 115 custom.dmacon = DMAF_AUD2; 116 /* restore period to previous value after beeping */ 117 custom.aud[2].audper = amiga_audio_period; 118 } 119