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macboing.c

/*
 *    Mac bong noise generator. Note - we ought to put a boingy noise
 *    here 8)
 *
 *    ----------------------------------------------------------------------
 *    16.11.98:
 *    rewrote some functions, added support for Enhanced ASC (Quadras)
 *    after the NetBSD asc.c console bell patch by Colin Wood/Frederick Bruck
 *    Juergen Mellinger (juergen.mellinger@t-online.de)
 */

#include <linux/sched.h>
#include <linux/timer.h>

#include <asm/macintosh.h>
#include <asm/mac_asc.h>

static int mac_asc_inited;
/*
 * dumb triangular wave table
 */
static __u8 mac_asc_wave_tab[ 0x800 ];

/*
 * Alan's original sine table; needs interpolating to 0x800
 * (hint: interpolate or hardwire [0 -> Pi/2[, it's symmetric)
 */
static const signed char sine_data[] = {
      0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
      0, -39, -75, -103, -121, -127, -121, -103, -75, -39
};

/*
 * where the ASC hides ...
 */
static volatile __u8* mac_asc_regs = ( void* )0x50F14000;

/*
 * sample rate; is this a good default value?
 */
static unsigned long mac_asc_samplespersec = 11050;
static int mac_bell_duration;
static unsigned long mac_bell_phase; /* 0..2*Pi -> 0..0x800 (wavetable size) */
static unsigned long mac_bell_phasepersample;

/*
 * some function protos
 */
static void mac_init_asc( void );
static void mac_nosound( unsigned long );
static void mac_quadra_start_bell( unsigned int, unsigned int, unsigned int );
static void mac_quadra_ring_bell( unsigned long );
static void mac_av_start_bell( unsigned int, unsigned int, unsigned int );
static void ( *mac_special_bell )( unsigned int, unsigned int, unsigned int );

/*
 * our timer to start/continue/stop the bell
 */
static DEFINE_TIMER(mac_sound_timer, mac_nosound, 0, 0);

/*
 * Sort of initialize the sound chip (called from mac_mksound on the first
 * beep).
 */
static void mac_init_asc( void )
{
      int i;

      /*
       * do some machine specific initialization
       * BTW:
       * the NetBSD Quadra patch identifies the Enhanced Apple Sound Chip via
       *    mac_asc_regs[ 0x800 ] & 0xF0 != 0
       * this makes no sense here, because we have to set the default sample
       * rate anyway if we want correct frequencies
       */
      switch ( macintosh_config->ident )
      {
            case MAC_MODEL_IIFX:
                  /*
                   * The IIfx is always special ...
                   */
                  mac_asc_regs = ( void* )0x50010000;
                  break;
                  /*
                   * not sure about how correct this list is
                   * machines with the EASC enhanced apple sound chip
                   */
            case MAC_MODEL_Q630:
            case MAC_MODEL_P475:
                  mac_special_bell = mac_quadra_start_bell;
                  mac_asc_samplespersec = 22150;
                  break;
            case MAC_MODEL_C660:
            case MAC_MODEL_Q840:
                  /*
                   * The Quadra 660AV and 840AV use the "Singer" custom ASIC for sound I/O.
                   * It appears to be similar to the "AWACS" custom ASIC in the Power Mac
                   * [678]100.  Because Singer and AWACS may have a similar hardware
                   * interface, this would imply that the code in drivers/sound/dmasound.c
                   * for AWACS could be used as a basis for Singer support.  All we have to
                   * do is figure out how to do DMA on the 660AV/840AV through the PSC and
                   * figure out where the Singer hardware sits in memory. (I'd look in the
                   * vicinity of the AWACS location in a Power Mac [678]100 first, or the
                   * current location of the Apple Sound Chip--ASC--in other Macs.)  The
                   * Power Mac [678]100 info can be found in MkLinux Mach kernel sources.
                   *
                   * Quoted from Apple's Tech Info Library, article number 16405:
                   *   "Among desktop Macintosh computers, only the 660AV, 840AV, and Power
                   *   Macintosh models have 16-bit audio input and output capability
                   *   because of the AT&T DSP3210 hardware circuitry and the 16-bit Singer
                   *   codec circuitry in the AVs.  The Audio Waveform Amplifier and
                   *   Converter (AWAC) chip in the Power Macintosh performs the same
                   *   16-bit I/O functionality.  The PowerBook 500 series computers
                   *   support 16-bit stereo output, but only mono input."
                   *
                   *   http://til.info.apple.com/techinfo.nsf/artnum/n16405
                   *
                   * --David Kilzer
                   */
                  mac_special_bell = mac_av_start_bell;
                  break;
            case MAC_MODEL_Q650:
            case MAC_MODEL_Q700:
            case MAC_MODEL_Q800:
            case MAC_MODEL_Q900:
            case MAC_MODEL_Q950:
                  /*
                   * Currently not implemented!
                   */
                  mac_special_bell = NULL;
                  break;
            default:
                  /*
                   * Every switch needs a default
                   */
                  mac_special_bell = NULL;
                  break;
      }

      /*
       * init the wave table with a simple triangular wave
       * A sine wave would sure be nicer here ...
       */
      for ( i = 0; i < 0x400; i++ )
      {
            mac_asc_wave_tab[ i ] = i / 4;
            mac_asc_wave_tab[ i + 0x400 ] = 0xFF - i / 4;
      }
      mac_asc_inited = 1;
}

/*
 * Called to make noise; current single entry to the boing driver.
 * Does the job for simple ASC, calls other routines else.
 * XXX Fixme:
 * Should be split into asc_mksound, easc_mksound, av_mksound and
 * function pointer set in mac_init_asc which would be called at
 * init time.
 * _This_ is rather ugly ...
 */
void mac_mksound( unsigned int freq, unsigned int length )
{
      __u32 cfreq = ( freq << 5 ) / 468;
      __u32 flags;
      int i;

      if ( mac_special_bell == NULL )
      {
            /* Do nothing */
            return;
      }

      if ( !mac_asc_inited )
            mac_init_asc();

      if ( mac_special_bell )
      {
            mac_special_bell( freq, length, 128 );
            return;
      }

      if ( freq < 20 || freq > 20000 || length == 0 )
      {
            mac_nosound( 0 );
            return;
      }

      local_irq_save(flags);

      del_timer( &mac_sound_timer );

      for ( i = 0; i < 0x800; i++ )
            mac_asc_regs[ i ] = 0;
      for ( i = 0; i < 0x800; i++ )
            mac_asc_regs[ i ] = mac_asc_wave_tab[ i ];

      for ( i = 0; i < 8; i++ )
            *( __u32* )( ( __u32 )mac_asc_regs + ASC_CONTROL + 0x814 + 8 * i ) = cfreq;

      mac_asc_regs[ 0x807 ] = 0;
      mac_asc_regs[ ASC_VOLUME ] = 128;
      mac_asc_regs[ 0x805 ] = 0;
      mac_asc_regs[ 0x80F ] = 0;
      mac_asc_regs[ ASC_MODE ] = ASC_MODE_SAMPLE;
      mac_asc_regs[ ASC_ENABLE ] = ASC_ENABLE_SAMPLE;

      mac_sound_timer.expires = jiffies + length;
      add_timer( &mac_sound_timer );

      local_irq_restore(flags);
}

/*
 * regular ASC: stop whining ..
 */
static void mac_nosound( unsigned long ignored )
{
      mac_asc_regs[ ASC_ENABLE ] = 0;
}

/*
 * EASC entry; init EASC, don't load wavetable, schedule 'start whining'.
 */
static void mac_quadra_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
{
      __u32 flags;

      /* if the bell is already ringing, ring longer */
      if ( mac_bell_duration > 0 )
      {
            mac_bell_duration += length;
            return;
      }

      mac_bell_duration = length;
      mac_bell_phase = 0;
      mac_bell_phasepersample = ( freq * sizeof( mac_asc_wave_tab ) ) / mac_asc_samplespersec;
      /* this is reasonably big for small frequencies */

      local_irq_save(flags);

      /* set the volume */
      mac_asc_regs[ 0x806 ] = volume;

      /* set up the ASC registers */
      if ( mac_asc_regs[ 0x801 ] != 1 )
      {
            /* select mono mode */
            mac_asc_regs[ 0x807 ] = 0;
            /* select sampled sound mode */
            mac_asc_regs[ 0x802 ] = 0;
            /* ??? */
            mac_asc_regs[ 0x801 ] = 1;
            mac_asc_regs[ 0x803 ] |= 0x80;
            mac_asc_regs[ 0x803 ] &= 0x7F;
      }

      mac_sound_timer.function = mac_quadra_ring_bell;
      mac_sound_timer.expires = jiffies + 1;
      add_timer( &mac_sound_timer );

      local_irq_restore(flags);
}

/*
 * EASC 'start/continue whining'; I'm not sure why the above function didn't
 * already load the wave table, or at least call this one...
 * This piece keeps reloading the wave table until done.
 */
static void mac_quadra_ring_bell( unsigned long ignored )
{
      int   i, count = mac_asc_samplespersec / HZ;
      __u32 flags;

      /*
       * we neither want a sound buffer overflow nor underflow, so we need to match
       * the number of samples per timer interrupt as exactly as possible.
       * using the asc interrupt will give better results in the future
       * ...and the possibility to use a real sample (a boingy noise, maybe...)
       */

      local_irq_save(flags);

      del_timer( &mac_sound_timer );

      if ( mac_bell_duration-- > 0 )
      {
            for ( i = 0; i < count; i++ )
            {
                  mac_bell_phase += mac_bell_phasepersample;
                  mac_asc_regs[ 0 ] = mac_asc_wave_tab[ mac_bell_phase & ( sizeof( mac_asc_wave_tab ) - 1 ) ];
            }
            mac_sound_timer.expires = jiffies + 1;
            add_timer( &mac_sound_timer );
      }
      else
            mac_asc_regs[ 0x801 ] = 0;

      local_irq_restore(flags);
}

/*
 * AV code - please fill in.
 */
static void mac_av_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
{
}

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