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
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