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1da177e4 LT |
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/jiffies.h> | |
13 | #include <linux/timer.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/string.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 (sizeof(sine_data)/sizeof(sine_data[0])) | |
26 | ||
27 | /* | |
28 | * The minimum period for audio may be modified by the frame buffer | |
29 | * device since it depends on htotal (for OCS/ECS/AGA) | |
30 | */ | |
31 | ||
32 | volatile unsigned short amiga_audio_min_period = 124; /* Default for pre-OCS */ | |
33 | ||
34 | #define MAX_PERIOD (65535) | |
35 | ||
36 | ||
37 | /* | |
38 | * Current period (set by dmasound.c) | |
39 | */ | |
40 | ||
41 | unsigned short amiga_audio_period = MAX_PERIOD; | |
42 | ||
43 | static unsigned long clock_constant; | |
44 | ||
45 | void __init amiga_init_sound(void) | |
46 | { | |
47 | static struct resource beep_res = { .name = "Beep" }; | |
48 | ||
49 | snd_data = amiga_chip_alloc_res(sizeof(sine_data), &beep_res); | |
50 | if (!snd_data) { | |
51 | printk (KERN_CRIT "amiga init_sound: failed to allocate chipmem\n"); | |
52 | return; | |
53 | } | |
54 | memcpy (snd_data, sine_data, sizeof(sine_data)); | |
55 | ||
56 | /* setup divisor */ | |
57 | clock_constant = (amiga_colorclock+DATA_SIZE/2)/DATA_SIZE; | |
58 | ||
59 | /* without amifb, turn video off and enable high quality sound */ | |
60 | #ifndef CONFIG_FB_AMIGA | |
61 | amifb_video_off(); | |
62 | #endif | |
63 | } | |
64 | ||
65 | static void nosound( unsigned long ignored ); | |
8d06afab | 66 | static DEFINE_TIMER(sound_timer, nosound, 0, 0); |
1da177e4 LT |
67 | |
68 | void amiga_mksound( unsigned int hz, unsigned int ticks ) | |
69 | { | |
70 | unsigned long flags; | |
71 | ||
72 | if (!snd_data) | |
73 | return; | |
74 | ||
75 | local_irq_save(flags); | |
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 | local_irq_restore(flags); | |
104 | } | |
105 | ||
106 | ||
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 | } |