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/pgtable.h>
  30 #include <asm/atariints.h>
  31
  32
  33 /*
  34  * stuff from the old atasound.c
  35  */
  36
  37 void 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 EXPORT_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
  54 void 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 }