sb_mixer.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

/*
 * sound/sb_mixer.c
 * 
 * The low level mixer driver for the SoundBlaster Pro and SB16 cards.
 * 
 * Copyright by Hannu Savolainen 1993
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer. 2.
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 */

#include "sound_config.h"

#if defined(CONFIGURE_SOUNDCARD) && !defined(EXCLUDE_SB) && !defined(EXCLUDE_SBPRO)
#define __SB_MIXER_C__

#include "sb.h"
#include "sb_mixer.h"
#undef SB_TEST_IRQ

extern int      sbc_base;

static int mixer_initialized = 0;

static int supported_rec_devices;
static int supported_devices;
static int recmask = 0;
static int mixer_model;
static int mixer_caps;
static mixer_tab *iomap;

void
sb_setmixer (unsigned int port, unsigned int value)
{
  unsigned long flags;

  DISABLE_INTR(flags);
  OUTB ((unsigned char)(port & 0xff), MIXER_ADDR);	/* Select register */
  tenmicrosec ();
  OUTB ((unsigned char)(value & 0xff), MIXER_DATA);
  tenmicrosec ();
  RESTORE_INTR(flags);
}

int
sb_getmixer (unsigned int port)
{
  int             val;
  unsigned long flags;

  DISABLE_INTR(flags);
  OUTB ((unsigned char)(port & 0xff), MIXER_ADDR);	/* Select register */
  tenmicrosec ();
  val = INB (MIXER_DATA);
  tenmicrosec ();
  RESTORE_INTR(flags);

  return val;
}

void
sb_mixer_set_stereo(int mode)
{
  if (!mixer_initialized) return;

  sb_setmixer (OUT_FILTER, ((sb_getmixer (OUT_FILTER) & ~STEREO_DAC)
			 | (mode ? STEREO_DAC : MONO_DAC)));
}

static int
detect_mixer (void)
{
  /*
   * Detect the mixer by changing parameters of two volume channels. If the
   * values read back match with the values written, the mixer is there (is
   * it?)
   */
  sb_setmixer (FM_VOL, 0xff);
  sb_setmixer (VOC_VOL, 0x33);

  if (sb_getmixer (FM_VOL) != 0xff)
    return 0;			/* No match */
  if (sb_getmixer (VOC_VOL) != 0x33)
    return 0;

  return 1;
}

static void
change_bits(unsigned char *regval, int dev, int chn, int newval)
{
	unsigned char mask;
	int shift;

	mask = (1 << (*iomap)[dev][chn].nbits)-1;
	newval = ((newval * mask) + 50) / 100;	/* Scale it */

	shift = (*iomap)[dev][chn].bitoffs-(*iomap)[dev][LEFT_CHN].nbits+1;

	*regval &= ~(mask << shift);	/* Filter out the previous value */
	*regval |= (newval & mask) << shift; /* Set the new value */
}

static int
sb_mixer_get(int dev)
{
	if (!((1<<dev) & supported_devices)) 
	   return RET_ERROR(EINVAL);

	return levels[dev];
}

static int
sb_mixer_set (int dev, int value)
{
	int left = value & 0x000000ff;
	int right = (value & 0x0000ff00) >> 8;

	int regoffs;
	unsigned char val;

	if (left > 100) left = 100;
	if (right > 100) right = 100;

	if (dev > 31) return RET_ERROR(EINVAL);

	if (!(supported_devices & (1 << dev)))	/* Not supported */
	   return RET_ERROR(EINVAL);

	regoffs = (*iomap)[dev][LEFT_CHN].regno;

	if (regoffs == 0)
	   return RET_ERROR(EINVAL);

	val = sb_getmixer(regoffs);
	change_bits(&val, dev, LEFT_CHN, left);

	levels[dev] = left|(left << 8);

	if ((*iomap)[dev][RIGHT_CHN].regno != regoffs) /* Change register */
	{
		sb_setmixer(regoffs, val);	/* Save the old one */
		regoffs = (*iomap)[dev][RIGHT_CHN].regno;

		if (regoffs == 0)
		   return left|(left << 8); /* Just left channel present */

		val = sb_getmixer(regoffs);	/* Read the new one */
	}

	change_bits(&val, dev, RIGHT_CHN, right);
	sb_setmixer(regoffs, val);

	levels[dev] = left | (right << 8);
	return left | (right << 8);
}

static void
set_recsrc(int src)
{
	sb_setmixer(RECORD_SRC, (sb_getmixer(RECORD_SRC)&~7) | (src&0x7));
}

static int
set_recmask(int mask)
{
      int devmask, i;
      unsigned char regimageL, regimageR;

      devmask = mask & supported_rec_devices;

      switch (mixer_model)
      {
      case 3:

      if (devmask != SOUND_MASK_MIC &&
	  devmask != SOUND_MASK_LINE &&
	  devmask != SOUND_MASK_CD)
	{			/* More than one devices selected. Drop the
				 * previous selection */
	  devmask &= ~recmask;
	}

      if (devmask != SOUND_MASK_MIC &&
	  devmask != SOUND_MASK_LINE &&
	  devmask != SOUND_MASK_CD)
	{			/* More than one devices selected. Default to
				 * mic */
	  devmask = SOUND_MASK_MIC;
	}


      if (devmask ^ recmask)/* Input source changed */
	{
	  switch (devmask)
	    {

	    case SOUND_MASK_MIC:
	      set_recsrc (SRC_MIC);
	      break;

	    case SOUND_MASK_LINE:
	      set_recsrc (SRC_LINE);
	      break;

	    case SOUND_MASK_CD:
	      set_recsrc (SRC_CD);
	      break;

	    default:
	      set_recsrc (SRC_MIC);
	    }
	}

      break;

      case 4:
	if (!devmask) devmask = SOUND_MASK_MIC;

        regimageL = regimageR = 0;
	for (i=0;i<SOUND_MIXER_NRDEVICES;i++)
	  if ((1<<i) & devmask)
	  {
	    regimageL |= sb16_recmasks_L[i];
	    regimageR |= sb16_recmasks_R[i];
	  }
	sb_setmixer(SB16_IMASK_L, regimageL);
	sb_setmixer(SB16_IMASK_R, regimageR);
      break;
      }

      recmask = devmask;
      return recmask;
}

static int
sb_mixer_ioctl (int dev, unsigned int cmd, unsigned int arg)
{
  if (((cmd >> 8) & 0xff) == 'M')
    {
      if (cmd & IOC_IN)
        switch (cmd & 0xff)
        {
        case SOUND_MIXER_RECSRC:
           return IOCTL_OUT(arg, set_recmask(IOCTL_IN(arg)));
           break;

	default:
	   return IOCTL_OUT (arg, sb_mixer_set (cmd & 0xff, IOCTL_IN (arg)));
        }
      else
	  switch (cmd & 0xff)	/* Return parameters */
	    {

	    case SOUND_MIXER_RECSRC:
	      return IOCTL_OUT (arg, recmask);
	      break;

	    case SOUND_MIXER_DEVMASK:
	      return IOCTL_OUT (arg, supported_devices);
	      break;

	    case SOUND_MIXER_STEREODEVS:
	      return IOCTL_OUT (arg, supported_devices & 
	                              ~(SOUND_MASK_MIC|SOUND_MASK_SPEAKER));
	      break;

	    case SOUND_MIXER_RECMASK:
	      return IOCTL_OUT (arg, supported_rec_devices);
	      break;

	    case SOUND_MIXER_CAPS:
	      return IOCTL_OUT (arg, mixer_caps);
	      break;

	    default:
	      return IOCTL_OUT (arg, sb_mixer_get (cmd & 0xff));
	    }
    }
  else
    return RET_ERROR (EINVAL);
}

static struct mixer_operations sb_mixer_operations =
{
  sb_mixer_ioctl
};

static void
sb_mixer_reset(void)
{
  int i;

  for (i = 0; i < SOUND_MIXER_NRDEVICES; i++)
    sb_mixer_set (i, levels[i]);
  set_recmask(SOUND_MASK_MIC);
}

void
sb_mixer_init(int major_model)
{
	sb_setmixer(0x00, 0);	/* Reset mixer */

	if (!detect_mixer()) return;	/* No mixer. Why? */

	mixer_initialized = 1;
	mixer_model = major_model;

        switch (major_model)
        {
        case 3:
	  mixer_caps = SOUND_CAP_EXCL_INPUT;
	  supported_devices = SBPRO_MIXER_DEVICES;
	  supported_rec_devices = SBPRO_RECORDING_DEVICES;
	  iomap = &sbpro_mix;
	  break;

	case 4:
	  mixer_caps = 0;
	  supported_devices = SB16_MIXER_DEVICES;
	  supported_rec_devices = SB16_RECORDING_DEVICES;
	  iomap = &sb16_mix;
	  break;

	default:
	  printk("SB Warning: Unsupported mixer type\n");
	  return;
	}

        mixer_devs[num_mixers++] = &sb_mixer_operations;
        sb_mixer_reset();
}

#endif