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
32/*
33 * stuff from the old atasound.c
34 */
35
36void atari_microwire_cmd (int cmd)
37{
38	tt_microwire.mask = 0x7ff;
39	tt_microwire.data = MW_LM1992_ADDR | cmd;
40
41	/* Busy wait for data being completely sent :-( */
42	while( tt_microwire.mask != 0x7ff)
43		;
44}
45EXPORT_SYMBOL(atari_microwire_cmd);
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}
110