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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/m68k/atari/atasound.c
3 *
4 * ++Geert: Moved almost all stuff to linux/drivers/sound/
5 *
6 * The author of atari_nosound, atari_mksound and atari_microwire_cmd is
7 * unknown. (++roman: That's me... :-)
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file COPYING in the main directory of this archive
11 * for more details.
12 *
13 * 1998-05-31 ++andreas: atari_mksound rewritten to always use the envelope,
14 * no timer, atari_nosound removed.
15 *
16 */
17
18
19#include <linux/sched.h>
20#include <linux/timer.h>
21#include <linux/major.h>
22#include <linux/fcntl.h>
23#include <linux/errno.h>
24#include <linux/mm.h>
25
26#include <asm/atarihw.h>
27#include <asm/system.h>
28#include <asm/irq.h>
29#include <asm/pgtable.h>
30#include <asm/atariints.h>
31
32
33/*
34 * stuff from the old atasound.c
35 */
36
37void atari_microwire_cmd (int cmd)
38{
39 tt_microwire.mask = 0x7ff;
40 tt_microwire.data = MW_LM1992_ADDR | cmd;
41
42 /* Busy wait for data being completely sent :-( */
43 while( tt_microwire.mask != 0x7ff)
44 ;
45}
46
47
48/* PSG base frequency */
49#define PSG_FREQ 125000
50/* PSG envelope base frequency times 10 */
51#define PSG_ENV_FREQ_10 78125
52
53void atari_mksound (unsigned int hz, unsigned int ticks)
54{
55 /* Generates sound of some frequency for some number of clock
56 ticks. */
57 unsigned long flags;
58 unsigned char tmp;
59 int period;
60
61 local_irq_save(flags);
62
63
64 /* Disable generator A in mixer control. */
65 sound_ym.rd_data_reg_sel = 7;
66 tmp = sound_ym.rd_data_reg_sel;
67 tmp |= 011;
68 sound_ym.wd_data = tmp;
69
70 if (hz) {
71 /* Convert from frequency value to PSG period value (base
72 frequency 125 kHz). */
73
74 period = PSG_FREQ / hz;
75
76 if (period > 0xfff) period = 0xfff;
77
78 /* Set generator A frequency to hz. */
79 sound_ym.rd_data_reg_sel = 0;
80 sound_ym.wd_data = period & 0xff;
81 sound_ym.rd_data_reg_sel = 1;
82 sound_ym.wd_data = (period >> 8) & 0xf;
83 if (ticks) {
84 /* Set length of envelope (max 8 sec). */
85 int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10;
86
87 if (length > 0xffff) length = 0xffff;
88 sound_ym.rd_data_reg_sel = 11;
89 sound_ym.wd_data = length & 0xff;
90 sound_ym.rd_data_reg_sel = 12;
91 sound_ym.wd_data = length >> 8;
92 /* Envelope form: max -> min single. */
93 sound_ym.rd_data_reg_sel = 13;
94 sound_ym.wd_data = 0;
95 /* Use envelope for generator A. */
96 sound_ym.rd_data_reg_sel = 8;
97 sound_ym.wd_data = 0x10;
98 } else {
99 /* Set generator A level to maximum, no envelope. */
100 sound_ym.rd_data_reg_sel = 8;
101 sound_ym.wd_data = 15;
102 }
103 /* Turn on generator A in mixer control. */
104 sound_ym.rd_data_reg_sel = 7;
105 tmp &= ~1;
106 sound_ym.wd_data = tmp;
107 }
108 local_irq_restore(flags);
109}