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/*

 * sound/pas2_midi.c

 *

 * The low level driver for the PAS Midi Interface.

 */

#include <linux/config.h>

#include "sound_config.h"

#if defined(CONFIG_PAS) && defined(CONFIG_MIDI)

static int      midi_busy = 0, input_opened = 0;

static int      my_dev;

static volatile int ofifo_bytes = 0;

static unsigned char tmp_queue[256];

static volatile int qlen;

static volatile unsigned char qhead, qtail;

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

static int

pas_midi_open (int dev, int mode,

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

               void            (*output) (int dev)

)

{

  int             err;

  unsigned long   flags;

  unsigned char   ctrl;

  if (midi_busy)

    {

      printk ("PAS2: Midi busy\n");

      return -(EBUSY);

    }

  /*

   * Reset input and output FIFO pointers

   */

  pas_write (0x20 | 0x40,

             0x178b);

  save_flags (flags);

  cli ();

  if ((err = pas_set_intr (0x10)) < 0)

    return err;

  /*

   * Enable input available and output FIFO empty interrupts

   */

  ctrl = 0;

  input_opened = 0;

  midi_input_intr = input;

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

    {

      ctrl |= 0x04;             /*

                                   * Enable input

                                 */

      input_opened = 1;

    }

  if (mode == OPEN_WRITE || mode == OPEN_READWRITE)

    {

      ctrl |= 0x08 |            /*

                                   * Enable output

                                 */

        0x10;

    }

  pas_write (ctrl,

             0x178b);

  /*

   * Acknowledge any pending interrupts

   */

  pas_write (0xff, 0x1B88);

  ofifo_bytes = 0;

  restore_flags (flags);

  midi_busy = 1;

  qlen = qhead = qtail = 0;

  return 0;

}

static void

pas_midi_close (int dev)

{

  /*

   * Reset FIFO pointers, disable intrs

   */

  pas_write (0x20 | 0x40, 0x178b);

  pas_remove_intr (0x10);

  midi_busy = 0;

}

static int

dump_to_midi (unsigned char midi_byte)

{

  int             fifo_space, x;

  fifo_space = ((x = pas_read (0x1B89)) >> 4) & 0x0f;

  if (fifo_space == 15 || (fifo_space < 2 && ofifo_bytes > 13))         /*

                                                                           * Fifo

                                                                           * full

                                                                         */

    {

      return 0;                  /*

                                 * Upper layer will call again

                                 */

    }

  ofifo_bytes++;

  pas_write (midi_byte, 0x178A);

  return 1;

}

static int

pas_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

pas_midi_start_read (int dev)

{

  return 0;

}

static int

pas_midi_end_read (int dev)

{

  return 0;

}

static int

pas_midi_ioctl (int dev, unsigned cmd, caddr_t arg)

{

  return -(EINVAL);

}

static void

pas_midi_kick (int dev)

{

  ofifo_bytes = 0;

}

static int

pas_buffer_status (int dev)

{

  return qlen;

}

#define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi"

#define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT

#include "midi_synth.h"

static struct midi_operations pas_midi_operations =

{

  {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},

  &std_midi_synth,

  {0},

  pas_midi_open,

  pas_midi_close,

  pas_midi_ioctl,

  pas_midi_out,

  pas_midi_start_read,

  pas_midi_end_read,

  pas_midi_kick,

  NULL,                         /*

                                 * command

                                 */

  pas_buffer_status,

  NULL

};

void

pas_midi_init (void)

{

  if (num_midis >= MAX_MIDI_DEV)

    {

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

      return;

    }

  std_midi_synth.midi_dev = my_dev = num_midis;

  midi_devs[num_midis++] = &pas_midi_operations;

}

void

pas_midi_interrupt (void)

{

  unsigned char   stat;

  int             i, incount;

  unsigned long   flags;

  stat = pas_read (0x1B88);

  if (stat & 0x04)              /*

                                   * Input byte available

                                 */

    {

      incount = pas_read (0x1B89) & 0x0f;       /*

                                                   * Input FIFO count

                                                 */

      if (!incount)

        incount = 16;

      for (i = 0; i < incount; i++)

        if (input_opened)

          {

            midi_input_intr (my_dev, pas_read (0x178A));

          }

        else

          pas_read (0x178A);    /*

                                 * Flush

                                 */

    }

  if (stat & (0x08 | 0x10))

    {

      if (!(stat & 0x08))

        {

          ofifo_bytes = 8;

        }

      else

        {

          ofifo_bytes = 0;

        }

      save_flags (flags);

      cli ();

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

        {

          qlen--;

          qhead++;

        }

      restore_flags (flags);

    }

  if (stat & 0x40)

    {

      printk ("MIDI output overrun %x,%x,%d \n", pas_read (0x1B89), stat, ofifo_bytes);

      ofifo_bytes = 100;

    }

  pas_write (stat, 0x1B88);     /*

                                   * Acknowledge interrupts

                                 */

}

#endif