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