/*
 * sound/uart6850.c
 *
 * Copyright by Hannu Savolainen 1993
 *
 * Mon Nov 22 22:38:35 MET 1993 marco@driq.home.usn.nl:
 *      added 6850 support, used with COVOX SoundMaster II and custom cards.
 *
 * 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"

#ifdef CONFIGURE_SOUNDCARD

#if !defined(EXCLUDE_UART6850) && !defined(EXCLUDE_MIDI)

#define	DATAPORT   (uart6850_base)	/*
					   * * * Midi6850 Data I/O Port on IBM
					   *  */
#define	COMDPORT   (uart6850_base+1)	/*
					   * * * Midi6850 Command Port on IBM   */
#define	STATPORT   (uart6850_base+1)	/*
					   * * * Midi6850 Status Port on IBM   */

#define uart6850_status()		INB(STATPORT)
#define input_avail()		((uart6850_status()&INPUT_AVAIL))
#define output_ready()		((uart6850_status()&OUTPUT_READY))
#define uart6850_cmd(cmd)	OUTB(cmd, COMDPORT)
#define uart6850_read()		INB(DATAPORT)
#define uart6850_write(byte)	OUTB(byte, DATAPORT)

#define	OUTPUT_READY	0x02	/*
				   * * * Mask for Data Read Ready Bit   */
#define	INPUT_AVAIL	0x01	/*
				   * * * Mask for Data Send Ready Bit   */

#define	UART_RESET	0x95	/*
				   * * * 6850 Total Reset Command   */
#define	UART_MODE_ON	0x03	/*
				   * * * 6850 Send/Receive UART Mode   */

static int      uart6850_opened = 0;
static int      uart6850_base = 0x330;
static int      uart6850_irq;
static int      uart6850_detected = 0;
static int      my_dev;

static int      reset_uart6850 (void);
static void     (*midi_input_intr) (int dev, unsigned char data);

static void
uart6850_input_loop (void)
{
  int             count;

  count = 10;

  while (count)			/*
				 * Not timed out
				 */
    if (input_avail ())
      {
	unsigned char   c = uart6850_read ();

	count = 100;

	if (uart6850_opened & OPEN_READ)
	  midi_input_intr (my_dev, c);
      }
    else
      while (!input_avail () && count)
	count--;
}

void
m6850intr (int unit, struct pt_regs * regs)
{
  printk ("M");
  if (input_avail ())
    uart6850_input_loop ();
}

/*
 * It looks like there is no input interrupts in the UART mode. Let's try
 * polling.
 */

static void
poll_uart6850 (unsigned long dummy)
{
  unsigned long   flags;

  DEFINE_TIMER (uart6850_timer, poll_uart6850);

  if (!(uart6850_opened & OPEN_READ))
    return;			/*
				 * No longer required
				 */

  DISABLE_INTR (flags);

  if (input_avail ())
    uart6850_input_loop ();

  ACTIVATE_TIMER (uart6850_timer, poll_uart6850, 1);	/*
							 * Come back later
							 */

  RESTORE_INTR (flags);
}

static int
uart6850_open (int dev, int mode,
	       void            (*input) (int dev, unsigned char data),
	       void            (*output) (int dev)
)
{
  if (uart6850_opened)
    {
      printk ("Midi6850: Midi busy\n");
      return RET_ERROR (EBUSY);
    }

  uart6850_cmd (UART_RESET);

  uart6850_input_loop ();

  midi_input_intr = input;
  uart6850_opened = mode;
  poll_uart6850 (0);		/*
				 * Enable input polling
				 */

  return 0;
}

static void
uart6850_close (int dev)
{
  uart6850_cmd (UART_MODE_ON);

  uart6850_opened = 0;
}

static int
uart6850_out (int dev, unsigned char midi_byte)
{
  int             timeout;
  unsigned long   flags;

  /*
   * Test for input since pending input seems to block the output.
   */

  DISABLE_INTR (flags);

  if (input_avail ())
    uart6850_input_loop ();

  RESTORE_INTR (flags);

  /*
   * Sometimes it takes about 13000 loops before the output becomes ready
   * (After reset). Normally it takes just about 10 loops.
   */

  for (timeout = 30000; timeout > 0 && !output_ready (); timeout--);	/*
									 * Wait
									 */

  if (!output_ready ())
    {
      printk ("Midi6850: Timeout\n");
      return 0;
    }

  uart6850_write (midi_byte);
  return 1;
}

static int
uart6850_command (int dev, unsigned char *midi_byte)
{
  return 1;
}

static int
uart6850_start_read (int dev)
{
  return 0;
}

static int
uart6850_end_read (int dev)
{
  return 0;
}

static int
uart6850_ioctl (int dev, unsigned cmd, unsigned arg)
{
  return RET_ERROR (EINVAL);
}

static void
uart6850_kick (int dev)
{
}

static int
uart6850_buffer_status (int dev)
{
  return 0;			/*
				 * No data in buffers
				 */
}

#define MIDI_SYNTH_NAME	"6850 UART Midi"
#define MIDI_SYNTH_CAPS	SYNTH_CAP_INPUT
#include "midi_synth.h"

static struct midi_operations uart6850_operations =
{
  {"6850 UART", 0, 0, SNDCARD_UART6850},
  &std_midi_synth,
  uart6850_open,
  uart6850_close,
  uart6850_ioctl,
  uart6850_out,
  uart6850_start_read,
  uart6850_end_read,
  uart6850_kick,
  uart6850_command,
  uart6850_buffer_status
};


long
attach_uart6850 (long mem_start, struct address_info *hw_config)
{
  int             ok, timeout;
  unsigned long   flags;

  if (num_midis >= MAX_MIDI_DEV)
    {
      printk ("Sound: Too many midi devices detected\n");
      return mem_start;
    }

  uart6850_base = hw_config->io_base;
  uart6850_irq = hw_config->irq;

  if (!uart6850_detected)
    return RET_ERROR (EIO);

  DISABLE_INTR (flags);

  for (timeout = 30000; timeout < 0 && !output_ready (); timeout--);	/*
									 * Wait
									 */
  uart6850_cmd (UART_MODE_ON);

  ok = 1;

  RESTORE_INTR (flags);

  printk (" <6850 Midi Interface>");

  std_midi_synth.midi_dev = my_dev = num_midis;
  midi_devs[num_midis++] = &uart6850_operations;
  return mem_start;
}

static int
reset_uart6850 (void)
{
  uart6850_read ();
  return 1;			/*
				 * OK
				 */
}


int
probe_uart6850 (struct address_info *hw_config)
{
  int             ok = 0;

  uart6850_base = hw_config->io_base;
  uart6850_irq = hw_config->irq;

  if (snd_set_irq_handler (uart6850_irq, m6850intr) < 0)
    return 0;

  ok = reset_uart6850 ();

  uart6850_detected = ok;
  return ok;
}

#endif

#endif