1/*
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#include <linux/module.h>
26
27#include <asm/atarihw.h>
28#include <asm/irq.h>
29#include <asm/atariints.h>
30
31#include "atari.h"
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}
46EXPORT_SYMBOL(atari_microwire_cmd);
47
48
49/* PSG base frequency */
50#define	PSG_FREQ	125000
51/* PSG envelope base frequency times 10 */
52#define PSG_ENV_FREQ_10	78125
53
54void atari_mksound (unsigned int hz, unsigned int ticks)
55{
56	/* Generates sound of some frequency for some number of clock
57	   ticks.  */
58	unsigned long flags;
59	unsigned char tmp;
60	int period;
61
62	local_irq_save(flags);
63
64
65	/* Disable generator A in mixer control.  */
66	sound_ym.rd_data_reg_sel = 7;
67	tmp = sound_ym.rd_data_reg_sel;
68	tmp |= 011;
69	sound_ym.wd_data = tmp;
70
71	if (hz) {
72	    /* Convert from frequency value to PSG period value (base
73	       frequency 125 kHz).  */
74
75	    period = PSG_FREQ / hz;
76
77	    if (period > 0xfff) period = 0xfff;
78
79	/* Set generator A frequency to hz.  */
80	sound_ym.rd_data_reg_sel = 0;
81	sound_ym.wd_data = period & 0xff;
82	sound_ym.rd_data_reg_sel = 1;
83	sound_ym.wd_data = (period >> 8) & 0xf;
84	if (ticks) {
85		/* Set length of envelope (max 8 sec).  */
86		int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10;
87
88		if (length > 0xffff) length = 0xffff;
89		sound_ym.rd_data_reg_sel = 11;
90		sound_ym.wd_data = length & 0xff;
91		sound_ym.rd_data_reg_sel = 12;
92		sound_ym.wd_data = length >> 8;
93		/* Envelope form: max -> min single.  */
94		sound_ym.rd_data_reg_sel = 13;
95		sound_ym.wd_data = 0;
96		/* Use envelope for generator A.  */
97		sound_ym.rd_data_reg_sel = 8;
98		sound_ym.wd_data = 0x10;
99	} else {
100		/* Set generator A level to maximum, no envelope.  */
101		sound_ym.rd_data_reg_sel = 8;
102		sound_ym.wd_data = 15;
103	}
104	/* Turn on generator A in mixer control.  */
105	sound_ym.rd_data_reg_sel = 7;
106	tmp &= ~1;
107	sound_ym.wd_data = tmp;
108	}
109	local_irq_restore(flags);
110}
111