sequencer.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

/*
 * sound/sequencer.c
 * 
 * The sequencer personality manager.
 * 
 * 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.
 * 
 */

#define SEQUENCER_C
#include "sound_config.h"

#ifdef CONFIGURE_SOUNDCARD

#ifndef EXCLUDE_SEQUENCER

static int      sequencer_ok = 0;

DEFINE_WAIT_QUEUE (seq_sleeper, seq_sleep_flag);
/* DEFINE_WAIT_QUEUE (midi_sleeper, midi_sleep_flag); */
#define midi_sleeper seq_sleeper
#define midi_sleep_flag seq_sleep_flag

static int      midi_opened[MAX_MIDI_DEV] =
{0};				/* 1 if the process has opened MIDI */
static int      midi_written[MAX_MIDI_DEV] =
{0};

long            seq_time = 0;	/* Reference point for the timer */

#include "tuning.h"

#define EV_SZ	8
#define IEV_SZ	4
static unsigned char *queue = NULL;	/* SEQ_MAX_QUEUE * EV_SZ bytes */
static unsigned char *iqueue = NULL;	/* SEQ_MAX_QUEUE * IEV_SZ bytes */

static volatile int qhead = 0, qtail = 0, qlen = 0;
static volatile int iqhead = 0, iqtail = 0, iqlen = 0;
static volatile int seq_playing = 0;
static int      sequencer_busy = 0;
static int      output_treshold;
static unsigned synth_open_mask;

static int      seq_queue (unsigned char *note);
static void     seq_startplay (void);
static int      seq_sync (void);
static void     seq_reset (void);
static int      pmgr_present[MAX_SYNTH_DEV] =
{0};

#if MAX_SYNTH_DEV > 15
#error Too many synthesizer devices
#endif

int
sequencer_read (int dev, struct fileinfo *file, snd_rw_buf * buf, int count)
{
  int             c = count, p = 0;

  dev = dev >> 4;

  if (dev)			/* Patch manager device */
    return pmgr_read (dev - 1, file, buf, count);

  while (c > 3)
    {
      if (!iqlen)
	{
	  DO_SLEEP (midi_sleeper, midi_sleep_flag, 0);

	  if (!iqlen)
	    return count - c;
	}

      COPY_TO_USER (buf, p, &iqueue[iqhead * IEV_SZ], IEV_SZ);
      p += 4;
      c -= 4;

      iqhead = (iqhead + 1) % SEQ_MAX_QUEUE;
      iqlen--;
    }

  return count - c;
}

static void
sequencer_midi_output (int dev)
{
  /* Currently NOP */
}

static void
copy_to_input (unsigned char *event)
{
  unsigned long   flags;

  if (iqlen >= (SEQ_MAX_QUEUE - 1))
    return;			/* Overflow */

  memcpy (&iqueue[iqtail * IEV_SZ], event, IEV_SZ);
  iqlen++;
  iqtail = (iqtail + 1) % SEQ_MAX_QUEUE;

  DISABLE_INTR (flags);
  if (SOMEONE_WAITING (midi_sleeper, midi_sleep_flag))
    {
      WAKE_UP (midi_sleeper, midi_sleep_flag);
    }
  RESTORE_INTR (flags);
}

static void
sequencer_midi_input (int dev, unsigned char data)
{
  int             tstamp;
  unsigned char   event[4];

  if (data == 0xfe)		/* Active sensing */
    return;			/* Ignore */

  tstamp = GET_TIME () - seq_time;	/* Time since open() */
  tstamp = (tstamp << 8) | SEQ_WAIT;

  copy_to_input ((unsigned char *) &tstamp);

  event[0] = SEQ_MIDIPUTC;
  event[1] = data;
  event[2] = dev;
  event[3] = 0;

  copy_to_input (event);
}

int
sequencer_write (int dev, struct fileinfo *file, snd_rw_buf * buf, int count)
{
  unsigned char   event[EV_SZ], ev_code;
  int             p = 0, c, ev_size;
  int             err;
  int             mode = file->mode & O_ACCMODE;

  dev = dev >> 4;

  DEB (printk ("sequencer_write(dev=%d, count=%d)\n", dev, count));

  if (mode == OPEN_READ)
    return RET_ERROR (EIO);

  if (dev)			/* Patch manager device */
    return pmgr_write (dev - 1, file, buf, count);

  c = count;

  while (c >= 4)
    {
      COPY_FROM_USER (event, buf, p, 4);
      ev_code = event[0];

      if (ev_code == SEQ_FULLSIZE)
	{
	  int             err;

	  dev = *(unsigned short *) &event[2];
	  if (dev < 0 || dev >= num_synths)
	    return RET_ERROR (ENXIO);

	  if (!(synth_open_mask & (1 << dev)))
	    return RET_ERROR (ENXIO);

	  err = synth_devs[dev]->load_patch (dev, *(short *) &event[0], buf, p + 4, c, 0);
	  if (err < 0)
	    return err;

	  return err;
	}

      if (ev_code == SEQ_EXTENDED || ev_code == SEQ_PRIVATE)
	{

	  ev_size = 8;

	  if (c < ev_size)
	    {
	      if (!seq_playing)
		seq_startplay ();
	      return count - c;
	    }

	  COPY_FROM_USER (&event[4], buf, p + 4, 4);

	}
      else
	ev_size = 4;

      if (event[0] == SEQ_MIDIPUTC)
	{

	  if (!midi_opened[event[2]])
	    {
	      int             mode;
	      int             dev = event[2];

	      if (dev >= num_midis)
		{
		  printk ("Sequencer Error: Nonexistent MIDI device %d\n", dev);
		  return RET_ERROR (ENXIO);
		}

	      mode = file->mode & O_ACCMODE;

	      if ((err = midi_devs[dev]->open (dev, mode,
			  sequencer_midi_input, sequencer_midi_output)) < 0)
		{
		  seq_reset ();
		  printk ("Sequencer Error: Unable to open Midi #%d\n", dev);
		  return err;
		}

	      midi_opened[dev] = 1;
	    }

	}

      if (!seq_queue (event))
	{

	  if (!seq_playing)
	    seq_startplay ();
	  return count - c;
	}

      p += ev_size;
      c -= ev_size;
    }

  if (!seq_playing)
    seq_startplay ();

  return count;
}

static int
seq_queue (unsigned char *note)
{

  /* Test if there is space in the queue */

  if (qlen >= SEQ_MAX_QUEUE)
    if (!seq_playing)
      seq_startplay ();		/* Give chance to drain the queue */

  if (qlen >= SEQ_MAX_QUEUE && !SOMEONE_WAITING (seq_sleeper, seq_sleep_flag))
    {
      /* Sleep until there is enough space on the queue */
      DO_SLEEP (seq_sleeper, seq_sleep_flag, 0);
    }

  if (qlen >= SEQ_MAX_QUEUE)
    return 0;			/* To be sure */

  memcpy (&queue[qtail * EV_SZ], note, EV_SZ);

  qtail = (qtail + 1) % SEQ_MAX_QUEUE;
  qlen++;

  return 1;
}

static int
extended_event (unsigned char *q)
{
  int             dev = q[2];

  if (dev < 0 || dev >= num_synths)
    return RET_ERROR (ENXIO);

  if (!(synth_open_mask & (1 << dev)))
    return RET_ERROR (ENXIO);

  switch (q[1])
    {
    case SEQ_NOTEOFF:
      synth_devs[dev]->kill_note (dev, q[3], q[5]);
      break;

    case SEQ_NOTEON:
      if (q[4] > 127 && q[4] != 255)
	return 0;

      synth_devs[dev]->start_note (dev, q[3], q[4], q[5]);
      break;

    case SEQ_PGMCHANGE:
      synth_devs[dev]->set_instr (dev, q[3], q[4]);
      break;

    case SEQ_AFTERTOUCH:
      synth_devs[dev]->aftertouch (dev, q[3], q[4]);
      break;

    case SEQ_BALANCE:
      synth_devs[dev]->panning (dev, q[3], (char) q[4]);
      break;

    case SEQ_CONTROLLER:
      synth_devs[dev]->controller (dev, q[3], q[4], *(short *) &q[5]);
      break;

    default:
      return RET_ERROR (EINVAL);
    }

  return 0;
}

static void
seq_startplay (void)
{
  int             this_one;
  unsigned long  *delay;
  unsigned char  *q;

  while (qlen > 0)
    {
      qhead = ((this_one = qhead) + 1) % SEQ_MAX_QUEUE;
      qlen--;

      q = &queue[this_one*EV_SZ];

      switch (q[0])
	{
	case SEQ_NOTEOFF:
	  if (synth_open_mask & (1 << 0))
	    if (synth_devs[0])
	      synth_devs[0]->kill_note (0, q[1], q[3]);
	  break;

	case SEQ_NOTEON:
	  if (q[4] < 128 || q[4] == 255)
	    if (synth_open_mask & (1 << 0))
	      if (synth_devs[0])
		synth_devs[0]->start_note (0, q[1], q[2], q[3]);
	  break;

	case SEQ_WAIT:
	  delay = (unsigned long *) q;	/* Bytes 1 to 3 are containing the
					 * delay in GET_TIME() */
	  *delay = (*delay >> 8) & 0xffffff;

	  if (*delay > 0)
	    {
	      long            time;

	      seq_playing = 1;
	      time = *delay;

	      request_sound_timer (time);

	      if ((SEQ_MAX_QUEUE - qlen) >= output_treshold)
		{
		  unsigned long   flags;

		  DISABLE_INTR (flags);
		  if (SOMEONE_WAITING (seq_sleeper, seq_sleep_flag))
		    {
		      WAKE_UP (seq_sleeper, seq_sleep_flag);
		    }
		  RESTORE_INTR (flags);
		}
	      return;		/* Stop here. Timer routine will continue
				 * playing after the delay */
	    }
	  break;

	case SEQ_PGMCHANGE:
	  if (synth_open_mask & (1 << 0))
	    if (synth_devs[0])
	      synth_devs[0]->set_instr (0, q[1], q[2]);
	  break;

	case SEQ_SYNCTIMER:	/* Reset timer */
	  seq_time = GET_TIME ();
	  break;

	case SEQ_MIDIPUTC:	/* Put a midi character */
	  if (midi_opened[q[2]])
	    {
	      int             dev;

	      dev = q[2];

	      if (!midi_devs[dev]->putc (dev, q[1]))
		{
		  /*
		   * Output FIFO is full. Wait one timer cycle and try again.
		   */

		  qlen++;
		  qhead = this_one;	/* Restore queue */
		  seq_playing = 1;
		  request_sound_timer (-1);
		  return;
		}
	      else
		midi_written[dev] = 1;
	    }
	  break;

	case SEQ_ECHO:
	  copy_to_input (q);	/* Echo back to the process */
	  break;

	case SEQ_PRIVATE:
	  if (q[1] < num_synths)
	    synth_devs[q[1]]->hw_control (q[1], q);
	  break;

	case SEQ_EXTENDED:
	  extended_event (q);
	  break;

	default:;
	}

    }

  seq_playing = 0;

  if ((SEQ_MAX_QUEUE - qlen) >= output_treshold)
    {
      unsigned long   flags;

      DISABLE_INTR (flags);
      if (SOMEONE_WAITING (seq_sleeper, seq_sleep_flag))
	{
	  WAKE_UP (seq_sleeper, seq_sleep_flag);
	}
      RESTORE_INTR (flags);
    }

}

int
sequencer_open (int dev, struct fileinfo *file)
  {
    int             retval, mode, i;

    dev = dev >> 4;
    mode = file->mode & O_ACCMODE;

    DEB (printk ("sequencer_open(dev=%d)\n", dev));

    if (!sequencer_ok)
      {
	printk ("Soundcard: Sequencer not initialized\n");
	return RET_ERROR (ENXIO);
      }

    if (dev)			/* Patch manager device */
      {
	int             err;

	dev--;
	if (pmgr_present[dev])
	  return RET_ERROR (EBUSY);
	if ((err = pmgr_open (dev)) < 0)
	  return err;		/* Failed */

	pmgr_present[dev] = 1;
	return err;
      }

    if (sequencer_busy)
      {
	printk ("Sequencer busy\n");
	return RET_ERROR (EBUSY);
      }

    if (!(num_synths + num_midis))
      return RET_ERROR (ENXIO);

    synth_open_mask = 0;

    if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
      for (i = 0; i < num_synths; i++)	/* Open synth devices */
	if (synth_devs[i]->open (i, mode) < 0)
	  printk ("Sequencer: Warning! Cannot open synth device #%d\n", i);
	else
	  synth_open_mask |= (1 << i);

    seq_time = GET_TIME ();

    for (i = 0; i < num_midis; i++)
      {
	midi_opened[i] = 0;
	midi_written[i] = 0;
      }

    if (mode == OPEN_READ || mode == OPEN_READWRITE)
      {				/* Initialize midi input devices */
	if (!num_midis)
	  {
	    printk ("Sequencer: No Midi devices. Input not possible\n");
	    return RET_ERROR (ENXIO);
	  }

	for (i = 0; i < num_midis; i++)
	  {
	    if ((retval = midi_devs[i]->open (i, mode,
			 sequencer_midi_input, sequencer_midi_output)) >= 0)
	      midi_opened[i] = 1;
	  }
      }

    sequencer_busy = 1;
    RESET_WAIT_QUEUE (seq_sleeper, seq_sleep_flag);
    RESET_WAIT_QUEUE (midi_sleeper, midi_sleep_flag);
    output_treshold = SEQ_MAX_QUEUE / 2;

    for (i = 0; i < num_synths; i++)
      if (pmgr_present[i])
	pmgr_inform (i, PM_E_OPENED, 0, 0, 0, 0);

    return 0;
  }

void
seq_drain_midi_queues (void)
{
  int             i, n;

  /*
   * Give the Midi drivers time to drain their output queues
   */

  n = 1;

  while (!PROCESS_ABORTING (midi_sleeper, midi_sleep_flag) && n)
    {
      n = 0;

      for (i = 0; i < num_midis; i++)
	if (midi_opened[i] && midi_written[i])
	  if (midi_devs[i]->buffer_status != NULL)
	    if (midi_devs[i]->buffer_status (i))
	      n++;

      /*
       * Let's have a delay
       */
      if (n)
	{
	  DO_SLEEP (seq_sleeper, seq_sleep_flag, HZ / 10);
	}
    }
}