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/arch/m68k/atari/atasound.c

https://bitbucket.org/evzijst/gittest
C | 109 lines | 58 code | 18 blank | 33 comment | 6 complexity | a3cbf89961fb1efcdbd445c4708cc852 MD5 | raw file
  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
 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}