LXR linux/arch/m68k/atari/atasound.c

   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/system.h>
  29#include <asm/irq.h>
  30#include <asm/pgtable.h>
  31#include <asm/atariints.h>
  32
  33
  34/*
  35 * stuff from the old atasound.c
  36 */
  37
  38void atari_microwire_cmd (int cmd)
  39{
  40        tt_microwire.mask = 0x7ff;
  41        tt_microwire.data = MW_LM1992_ADDR | cmd;
  42
  43        /* Busy wait for data being completely sent :-( */
  44        while( tt_microwire.mask != 0x7ff)
  45                ;
  46}
  47EXPORT_SYMBOL(atari_microwire_cmd);
  48
  49
  50/* PSG base frequency */
  51#define PSG_FREQ        125000
  52/* PSG envelope base frequency times 10 */
  53#define PSG_ENV_FREQ_10 78125
  54
  55void atari_mksound (unsigned int hz, unsigned int ticks)
  56{
  57        /* Generates sound of some frequency for some number of clock
  58           ticks.  */
  59        unsigned long flags;
  60        unsigned char tmp;
  61        int period;
  62
  63        local_irq_save(flags);
  64
  65
  66        /* Disable generator A in mixer control.  */
  67        sound_ym.rd_data_reg_sel = 7;
  68        tmp = sound_ym.rd_data_reg_sel;
  69        tmp |= 011;
  70        sound_ym.wd_data = tmp;
  71
  72        if (hz) {
  73            /* Convert from frequency value to PSG period value (base
  74               frequency 125 kHz).  */
  75
  76            period = PSG_FREQ / hz;
  77
  78            if (period > 0xfff) period = 0xfff;
  79
  80        /* Set generator A frequency to hz.  */
  81        sound_ym.rd_data_reg_sel = 0;
  82        sound_ym.wd_data = period & 0xff;
  83        sound_ym.rd_data_reg_sel = 1;
  84        sound_ym.wd_data = (period >> 8) & 0xf;
  85        if (ticks) {
  86                /* Set length of envelope (max 8 sec).  */
  87                int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10;
  88
  89                if (length > 0xffff) length = 0xffff;
  90                sound_ym.rd_data_reg_sel = 11;
  91                sound_ym.wd_data = length & 0xff;
  92                sound_ym.rd_data_reg_sel = 12;
  93                sound_ym.wd_data = length >> 8;
  94                /* Envelope form: max -> min single.  */
  95                sound_ym.rd_data_reg_sel = 13;
  96                sound_ym.wd_data = 0;
  97                /* Use envelope for generator A.  */
  98                sound_ym.rd_data_reg_sel = 8;
  99                sound_ym.wd_data = 0x10;
 100        } else {
 101                /* Set generator A level to maximum, no envelope.  */
 102                sound_ym.rd_data_reg_sel = 8;
 103                sound_ym.wd_data = 15;
 104        }
 105        /* Turn on generator A in mixer control.  */
 106        sound_ym.rd_data_reg_sel = 7;
 107        tmp &= ~1;
 108        sound_ym.wd_data = tmp;
 109        }
 110        local_irq_restore(flags);
 111}
 112