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/*

 * sound/gus2_midi.c

 *

 * The low level driver for the GUS Midi Interface.

 */

/*

 * Copyright (C) by Hannu Savolainen 1993-1996

 *

 * USS/Lite for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)

 * Version 2 (June 1991). See the "COPYING" file distributed with this software

 * for more info.

 */

#include <linux/config.h>

#include "sound_config.h"

#include "gus_hw.h"

#if defined(CONFIG_GUS) && defined(CONFIG_MIDI)

static int      midi_busy = 0, input_opened = 0;

static int      my_dev;

static int      output_used = 0;

static volatile unsigned char gus_midi_control;

static void     (*midi_input_intr) (int dev, unsigned char data);

static unsigned char tmp_queue[256];

static volatile int qlen;

static volatile unsigned char qhead, qtail;

extern int      gus_base, gus_irq, gus_dma;

extern int     *gus_osp;

static int

GUS_MIDI_STATUS (void)

{

  return inb (u_MidiStatus);

}

static int

gus_midi_open (int dev, int mode,

               void            (*input) (int dev, unsigned char data),

               void            (*output) (int dev)

)

{

  if (midi_busy)

    {

      printk ("GUS: Midi busy\n");

      return -(EBUSY);

    }

  outb (MIDI_RESET, u_MidiControl);

  gus_delay ();

  gus_midi_control = 0;

  input_opened = 0;

  if (mode == OPEN_READ || mode == OPEN_READWRITE)

    {

      gus_midi_control |= MIDI_ENABLE_RCV;

      input_opened = 1;

    }

  outb (gus_midi_control, u_MidiControl);       /* Enable */

  midi_busy = 1;

  qlen = qhead = qtail = output_used = 0;

  midi_input_intr = input;

  return 0;

}

static int

dump_to_midi (unsigned char midi_byte)

{

  unsigned long   flags;

  int             ok = 0;

  output_used = 1;

  save_flags (flags);

  cli ();

  if (GUS_MIDI_STATUS () & MIDI_XMIT_EMPTY)

    {

      ok = 1;

      outb (midi_byte, u_MidiData);

    }

  else

    {

      /*

       * Enable Midi xmit interrupts (again)

       */

      gus_midi_control |= MIDI_ENABLE_XMIT;

      outb (gus_midi_control, u_MidiControl);

    }

  restore_flags (flags);

  return ok;

}

static void

gus_midi_close (int dev)

{

  /*

   * Reset FIFO pointers, disable intrs

   */

  outb (MIDI_RESET, u_MidiControl);

  midi_busy = 0;

}

static int

gus_midi_out (int dev, unsigned char midi_byte)

{

  unsigned long   flags;

  /*

   * Drain the local queue first

   */

  save_flags (flags);

  cli ();

  while (qlen && dump_to_midi (tmp_queue[qhead]))

    {

      qlen--;

      qhead++;

    }

  restore_flags (flags);

  /*

   * Output the byte if the local queue is empty.

   */

  if (!qlen)

    if (dump_to_midi (midi_byte))

      return 1;                 /*

                                 * OK

                                 */

  /*

   * Put to the local queue

   */

  if (qlen >= 256)

    return 0;                    /*

                                 * Local queue full

                                 */

  save_flags (flags);

  cli ();

  tmp_queue[qtail] = midi_byte;

  qlen++;

  qtail++;

  restore_flags (flags);

  return 1;

}

static int

gus_midi_start_read (int dev)

{

  return 0;

}

static int

gus_midi_end_read (int dev)

{

  return 0;

}

static int

gus_midi_ioctl (int dev, unsigned cmd, caddr_t arg)

{

  return -(EINVAL);

}

static void

gus_midi_kick (int dev)

{

}

static int

gus_midi_buffer_status (int dev)

{

  unsigned long   flags;

  if (!output_used)

    return 0;

  save_flags (flags);

  cli ();

  if (qlen && dump_to_midi (tmp_queue[qhead]))

    {

      qlen--;

      qhead++;

    }

  restore_flags (flags);

  return (qlen > 0) | !(GUS_MIDI_STATUS () & MIDI_XMIT_EMPTY);

}

#define MIDI_SYNTH_NAME "Gravis Ultrasound Midi"

#define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT

#include "midi_synth.h"

static struct midi_operations gus_midi_operations =

{

  {"Gravis UltraSound Midi", 0, 0, SNDCARD_GUS},

  &std_midi_synth,

  {0},

  gus_midi_open,

  gus_midi_close,

  gus_midi_ioctl,

  gus_midi_out,

  gus_midi_start_read,

  gus_midi_end_read,

  gus_midi_kick,

  NULL,                         /*

                                 * command

                                 */

  gus_midi_buffer_status,

  NULL

};

void

gus_midi_init (void)

{

  if (num_midis >= MAX_MIDI_DEV)

    {

      printk ("Sound: Too many midi devices detected\n");

      return;

    }

  outb (MIDI_RESET, u_MidiControl);

  std_midi_synth.midi_dev = my_dev = num_midis;

  midi_devs[num_midis++] = &gus_midi_operations;

  return;

}

void

gus_midi_interrupt (int dummy)

{

  volatile unsigned char stat, data;

  unsigned long   flags;

  int             timeout = 10;

  save_flags (flags);

  cli ();

  while (timeout-- > 0 && (stat = GUS_MIDI_STATUS ()) & (MIDI_RCV_FULL | MIDI_XMIT_EMPTY))

    {

      if (stat & MIDI_RCV_FULL)

        {

          data = inb (u_MidiData);

          if (input_opened)

            midi_input_intr (my_dev, data);

        }

      if (stat & MIDI_XMIT_EMPTY)

        {

          while (qlen && dump_to_midi (tmp_queue[qhead]))

            {

              qlen--;

              qhead++;

            }

          if (!qlen)

            {

              /*

               * Disable Midi output interrupts, since no data in the buffer

               */

              gus_midi_control &= ~MIDI_ENABLE_XMIT;

              outb (gus_midi_control, u_MidiControl);

              outb (gus_midi_control, u_MidiControl);

            }

        }

    }

  restore_flags (flags);

}

#endif