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( 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( 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( unused: 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 | |