sb_dsp.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

    dsp_speaker (OFF);

  sb_irq_mode = IMODE_INPUT;
  DMAbuf_start_dma (dev, buf, count, DMA_MODE_READ);

  if (sound_dsp_dmachan[dev] > 3)
    count >>= 1;
  count--;

  if (sb_dsp_highspeed)
    {
      DISABLE_INTR (flags);
      if (sb_dsp_command (0x48))	/* High speed size */
	{
	  sb_dsp_command ((unsigned char)(count & 0xff));
	  sb_dsp_command ((unsigned char)((count >> 8) & 0xff));
	  sb_dsp_command (0x99);	/* High speed 8 bit ADC */
	}
      else
	printk ("SB Error: Unable to start (high speed) ADC\n");
      RESTORE_INTR (flags);
    }
  else
    {
      DISABLE_INTR (flags);
      if (sb_dsp_command (0x24))	/* 8-bit ADC (DMA) */
	{
	  sb_dsp_command ((unsigned char)(count & 0xff));
	  sb_dsp_command ((unsigned char)((count >> 8) & 0xff));
	}
      else
	printk ("SB Error: Unable to start ADC\n");
      RESTORE_INTR (flags);
    }

  sb_intr_active = 1;
}

static void
dsp_cleanup (void)
{
  sb_intr_active = 0;
}

static int
sb_dsp_prepare_for_input (int dev, int bsize, int bcount)
{
  dsp_cleanup ();
  dsp_speaker (OFF);

  if (major == 3)	/* SB Pro */
  {
    if (dsp_stereo)
       sb_dsp_command(0xa8);
    else
       sb_dsp_command(0xa0);

    dsp_speed (dsp_current_speed);/* Speed must be recalculated if #channels
				   * changes */
  }
  return 0;
}

static int
sb_dsp_prepare_for_output (int dev, int bsize, int bcount)
{
  dsp_cleanup ();
  dsp_speaker (ON);

#ifndef EXCLUDE_SBPRO
  if (major == 3)	/* SB Pro */
  {
    sb_mixer_set_stereo(dsp_stereo);
    dsp_speed (dsp_current_speed);/* Speed must be recalculated if #channels
				   * changes */
  }
#endif
  return 0;
}

static void
sb_dsp_halt_xfer (int dev)
{
}

static int
verify_irq (void)
{
#if 0
  DEFINE_WAIT_QUEUE(testq, testf);

  irq_ok = 0;

  if (sb_get_irq () == -1)
    {
      printk ("*** SB Error: Irq %d already in use\n", sbc_irq);
      return 0;
    }


  sb_irq_mode = IMODE_INIT;

  sb_dsp_command (0xf2);		/* This should cause immediate interrupt */

  DO_SLEEP(testq, testf, HZ / 5);

  sb_free_irq();

  if (!irq_ok)
    {
      printk ("SB Warning: IRQ%d test not passed!", sbc_irq);
      irq_ok = 1;
    }
#else
  irq_ok = 1;
#endif
  return irq_ok;
}

static int
sb_dsp_open (int dev, int mode)
{
  int             retval;

  if (!sb_dsp_ok)
    {
      printk ("SB Error: SoundBlaster board not installed\n");
      return RET_ERROR (ENXIO);
    }

  if (sb_intr_active || (sb_midi_busy && sb_midi_mode == UART_MIDI))
    {
      printk ("SB: PCM not possible during MIDI input\n");
      return RET_ERROR (EBUSY);
    }

  if (!irq_verified)
    {
  	verify_irq();
  	irq_verified = 1;
    }
  else
    if (!irq_ok)
       printk("SB Warning: Incorrect IRQ setting %d\n",
  	      sbc_irq);

  retval = sb_get_irq ();
  if (retval)
    return retval;

  if (!DMAbuf_open_dma (dev))
    {
      sb_free_irq ();
      printk ("SB: DMA Busy\n");
      return RET_ERROR (EBUSY);
    }

  sb_irq_mode = IMODE_NONE;

  sb_dsp_busy = 1;

  return 0;
}

static void
sb_dsp_close (int dev)
{
  DMAbuf_close_dma (dev);
  sb_free_irq ();
  dsp_cleanup ();
  dsp_speaker (OFF);
  sb_dsp_busy = 0;
  sb_dsp_highspeed = 0;
}

static int
sb_dsp_ioctl (int dev, unsigned int cmd, unsigned int arg, int local)
{
  switch (cmd)
    {
    case SOUND_PCM_WRITE_RATE:
      if (local)
	return dsp_speed (arg);
      return IOCTL_OUT (arg, dsp_speed (IOCTL_IN (arg)));
      break;

    case SOUND_PCM_READ_RATE:
      if (local)
	return dsp_current_speed;
      return IOCTL_OUT (arg, dsp_current_speed);
      break;

    case SOUND_PCM_WRITE_CHANNELS:
      if (local)
         return dsp_set_stereo (arg - 1) + 1;
      return IOCTL_OUT (arg, dsp_set_stereo (IOCTL_IN (arg) - 1) + 1);
      break;

    case SOUND_PCM_READ_CHANNELS:
      if (local)
	return dsp_stereo + 1;
      return IOCTL_OUT (arg, dsp_stereo + 1);
      break;

    case SNDCTL_DSP_STEREO:
      if (local)
	return dsp_set_stereo (arg);
      return IOCTL_OUT (arg, dsp_set_stereo (IOCTL_IN (arg)));
      break;

    case SOUND_PCM_WRITE_BITS:
    case SOUND_PCM_READ_BITS:
      if (local)
	return 8;
      return IOCTL_OUT (arg, 8);/* Only 8 bits/sample supported */
      break;

    case SOUND_PCM_WRITE_FILTER:
    case SOUND_PCM_READ_FILTER:
      return RET_ERROR (EINVAL);
      break;

    default:
      return RET_ERROR (EINVAL);
    }

  return RET_ERROR (EINVAL);
}

static void
sb_dsp_reset (int dev)
{
  unsigned long   flags;

  DISABLE_INTR (flags);

  sb_reset_dsp ();
  dsp_cleanup ();

  RESTORE_INTR (flags);
}

#endif

int
sb_dsp_detect (struct address_info *hw_config)
{
  sbc_base = hw_config->io_base;
  sbc_irq = hw_config->irq;

  if (sb_dsp_ok)
    return 0;			/* Already initialized */

  if (!sb_reset_dsp ())
    return 0;

  return 1;			/* Detected */
}

#ifndef EXCLUDE_AUDIO
static struct audio_operations sb_dsp_operations =
{
  "SoundBlaster",
  sb_dsp_open,
  sb_dsp_close,
  sb_dsp_output_block,
  sb_dsp_start_input,
  sb_dsp_ioctl,
  sb_dsp_prepare_for_input,
  sb_dsp_prepare_for_output,
  sb_dsp_reset,
  sb_dsp_halt_xfer,
  NULL,				/* has_output_drained */
  NULL				/* copy_from_user */
};

#endif

long
sb_dsp_init (long mem_start, struct address_info *hw_config)
{
  int             i;

  major = minor = 0;
  sb_dsp_command (0xe1);		/* Get version */

  for (i = 1000; i; i--)
    {
      if (INB (DSP_DATA_AVAIL) & 0x80)
	{			/* wait for Data Ready */
	  if (major == 0)
	    major = INB (DSP_READ);
	  else
	    {
	      minor = INB (DSP_READ);
	      break;
	    }
	}
    }

      if (major == 2 || major == 3)
	sb_duplex_midi = 1;

      if (major == 4)
	sb16 = 1;

      if (major >= 3)
	sb_dsp_model = 2;

#ifndef EXCLUDE_SBPRO
      if (major >= 3)
         sb_mixer_init(major);
#endif

#ifndef EXCLUDE_YM3812
      if (major > 3 || (major == 3 && minor > 0))	/* SB Pro2 or later */
	{
	  enable_opl3_mode (OPL3_LEFT, OPL3_RIGHT, OPL3_BOTH);
	}
#endif

    if (major >= 3)
      {
#ifndef SCO
      	sprintf (sb_dsp_operations.name, "SoundBlaster Pro %d.%d", major, minor);
#endif
      }
    else
      {
#ifndef SCO
    	sprintf (sb_dsp_operations.name, "SoundBlaster %d.%d", major, minor);
#endif
      }

  printk (" <%s>", sb_dsp_operations.name);

#ifndef EXCLUDE_AUDIO
#  if !defined(EXCLUDE_SB16) && !defined(EXCLUDE_SBPRO)
  if (!sb16)	/* There is a better driver for SB16	*/
#  endif
  if (num_dspdevs < MAX_DSP_DEV)
    {
      dsp_devs[my_dev = num_dspdevs++] = &sb_dsp_operations;
      sound_buffcounts[my_dev] = DSP_BUFFCOUNT;
      sound_buffsizes[my_dev] = DSP_BUFFSIZE;
      sound_dsp_dmachan[my_dev] = hw_config->dma;
      sound_dma_automode[my_dev] = 0;
    }
  else
    printk ("SB: Too many DSP devices available\n");
#endif

#ifndef EXCLUDE_MIDI
  if (!midi_disabled && !sb16)	/* Midi don't work in the SB emulation mode
				 * of PAS, SB16 has better midi interface */
	sb_midi_init(major);
#endif

  sb_dsp_ok = 1;
  return mem_start;
}

void
sb_dsp_disable_midi (void)
{
  midi_disabled = 1;
}

#endif