atasound.c
2.62 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
/*
* linux/arch/m68k/atari/atasound.c
*
* ++Geert: Moved almost all stuff to linux/drivers/sound/
*
* The author of atari_nosound, atari_mksound and atari_microwire_cmd is
* unknown. (++roman: That's me... :-)
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*
* 1998-05-31 ++andreas: atari_mksound rewritten to always use the envelope,
* no timer, atari_nosound removed.
*
*/
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fcntl.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <asm/atarihw.h>
#include <asm/irq.h>
#include <asm/pgtable.h>
#include <asm/atariints.h>
/*
* stuff from the old atasound.c
*/
void atari_microwire_cmd (int cmd)
{
tt_microwire.mask = 0x7ff;
tt_microwire.data = MW_LM1992_ADDR | cmd;
/* Busy wait for data being completely sent :-( */
while( tt_microwire.mask != 0x7ff)
;
}
EXPORT_SYMBOL(atari_microwire_cmd);
/* PSG base frequency */
#define PSG_FREQ 125000
/* PSG envelope base frequency times 10 */
#define PSG_ENV_FREQ_10 78125
void atari_mksound (unsigned int hz, unsigned int ticks)
{
/* Generates sound of some frequency for some number of clock
ticks. */
unsigned long flags;
unsigned char tmp;
int period;
local_irq_save(flags);
/* Disable generator A in mixer control. */
sound_ym.rd_data_reg_sel = 7;
tmp = sound_ym.rd_data_reg_sel;
tmp |= 011;
sound_ym.wd_data = tmp;
if (hz) {
/* Convert from frequency value to PSG period value (base
frequency 125 kHz). */
period = PSG_FREQ / hz;
if (period > 0xfff) period = 0xfff;
/* Set generator A frequency to hz. */
sound_ym.rd_data_reg_sel = 0;
sound_ym.wd_data = period & 0xff;
sound_ym.rd_data_reg_sel = 1;
sound_ym.wd_data = (period >> 8) & 0xf;
if (ticks) {
/* Set length of envelope (max 8 sec). */
int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10;
if (length > 0xffff) length = 0xffff;
sound_ym.rd_data_reg_sel = 11;
sound_ym.wd_data = length & 0xff;
sound_ym.rd_data_reg_sel = 12;
sound_ym.wd_data = length >> 8;
/* Envelope form: max -> min single. */
sound_ym.rd_data_reg_sel = 13;
sound_ym.wd_data = 0;
/* Use envelope for generator A. */
sound_ym.rd_data_reg_sel = 8;
sound_ym.wd_data = 0x10;
} else {
/* Set generator A level to maximum, no envelope. */
sound_ym.rd_data_reg_sel = 8;
sound_ym.wd_data = 15;
}
/* Turn on generator A in mixer control. */
sound_ym.rd_data_reg_sel = 7;
tmp &= ~1;
sound_ym.wd_data = tmp;
}
local_irq_restore(flags);
}