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