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/sched.h>
13 #include <linux/timer.h>
14 #include <linux/init.h>
15
16 #include <asm/system.h>
17 #include <asm/amigahw.h>
18
19 static unsigned short *snd_data = NULL;
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 /*
27 * The minimum period for audio may be modified by the frame buffer
28 * device since it depends on htotal (for OCS/ECS/AGA)
29 */
30
31 volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */
32
33 #define MAX_PERIOD (65535)
34
35
36 /*
37 * Current period (set by dmasound.c)
38 */
39
40 unsigned short amiga_audio_period = MAX_PERIOD;
41
42 static unsigned long clock_constant;
43
amiga_init_sound(void)44 void __init amiga_init_sound(void)
45 {
46 static struct resource beep_res = { "Beep" };
47
48 snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res);
49 if (!snd_data) {
50 printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n");
51 return;
52 }
53 memcpy (snd_data, sine_data, sizeof(sine_data));
54
55 /* setup divisor */
56 clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE;
57
58 /* without amifb, turn video off and enable high quality sound */
59 #ifndef CONFIG_FB_AMIGA
60 amifb_video_off();
61 #endif
62 }
63
64 static void nosound( unsigned long ignored );
65 static struct timer_list sound_timer = { function: nosound };
66
amiga_mksound(unsigned int hz,unsigned int ticks)67 void amiga_mksound( unsigned int hz, unsigned int ticks )
68 {
69 unsigned long flags;
70
71 if (!snd_data)
72 return;
73
74 save_flags(flags);
75 cli();
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 restore_flags(flags);
104 }
105
106
nosound(unsigned long ignored)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