2 * linux/arch/m68k/amiga/amisound.c
4 * amiga sound driver for Linux/m68k
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
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>
17 #include <asm/system.h>
18 #include <asm/amigahw.h>
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
25 #define DATA_SIZE (sizeof(sine_data)/sizeof(sine_data[0]))
27 #define custom amiga_custom
30 * The minimum period for audio may be modified by the frame buffer
31 * device since it depends on htotal (for OCS/ECS/AGA)
34 volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */
36 #define MAX_PERIOD (65535)
40 * Current period (set by dmasound.c)
43 unsigned short amiga_audio_period = MAX_PERIOD;
45 static unsigned long clock_constant;
47 void __init amiga_init_sound(void)
49 static struct resource beep_res = { .name = "Beep" };
51 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);
53 printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n");
56 memcpy (snd_data, sine_data, sizeof(sine_data));
59 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
61 /* without amifb, turn video off and enable high quality sound */
62 #ifndef CONFIG_FB_AMIGA
67 static void nosound( unsigned long ignored );
68 static DEFINE_TIMER(sound_timer, nosound, 0, 0);
70 void amiga_mksound( unsigned int hz, unsigned int ticks )
77 local_irq_save(flags);
78 del_timer( &sound_timer );
80 if (hz > 20 && hz < 32767) {
81 unsigned long period = (clock_constant / hz);
83 if (period < amiga_audio_min_period)
84 period = amiga_audio_min_period;
85 if (period > MAX_PERIOD)
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 */
95 sound_timer.expires = jiffies + ticks;
96 add_timer( &sound_timer );
99 /* turn on DMA for audio channel 2 */
100 custom.dmacon = DMAF_SETCLR | DMAF_AUD2;
105 local_irq_restore(flags);
109 static void nosound( unsigned long ignored )
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;