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/irq.h>
  29 #include <asm/atariints.h>
  30
  31
  32 /*
  33  * stuff from the old atasound.c
  34  */
  35
  36 void 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 }
  45 EXPORT_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
  53 void 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 }