/* Remote serial interface for local (hardwired) serial ports for GO32.
   Copyright 1992, 1993 Free Software Foundation, Inc.

This file is part of GDB.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "defs.h"
#include "serial.h"
#include <sys/dos.h>

#define SIGNATURE 0x4154
#define VERSION 1
#define OFFSET 0x104

#define peek(a,b) (*(unsigned short *)(0xe0000000 + (a)*16 + (b)))

typedef struct {
  short jmp_op;
  short signature;
  short version;
  short buffer_start;
  short buffer_end;
  short getp;
  short putp;
  short iov;
} ASYNC_STRUCT;

static ASYNC_STRUCT *async;
static int iov;
#define com_rb	iov
#define com_tb	iov
#define com_ier	iov+1
#define com_ifr	iov+2
#define com_bfr	iov+3
#define com_mcr	iov+4
#define com_lsr	iov+5
#define com_msr	iov+6

static int fd;

static char *
aptr(p)
     short p;
{
  return (char *)((unsigned)async - OFFSET + p);
}

static ASYNC_STRUCT *
getivec(int which)
{
  ASYNC_STRUCT *a;

  if (peek(0, which*4) != OFFSET)
    return 0;
  a = (ASYNC_STRUCT *)(0xe0000000 + peek(0, which*4+2)*16 + peek(0, which*4));

  if (a->signature != SIGNATURE)
    return 0;
  if (a->version != VERSION)
    return 0;
  return a;
}

static int
dos_async_init()
{
  int i;
  ASYNC_STRUCT *a1;
  ASYNC_STRUCT *a2;
  a1 = getivec(12);
  a2 = getivec(11);
  async = 0;
  if (a1)
    async = a1;
  if (a2)
    async = a2;
  if (a1 && a2)
  {
    if (a1 < a2)
      async = a1;
    else
      async = a2;
  }
  if (async == 0)
  {
    error("GDB can not connect to asynctsr program, check that it is installed\n\
and that serial I/O is not being redirected (perhaps by NFS)\n\n\
example configuration:\n\
C> mode com2:9600,n,8,1,p\n\
C> asynctsr 2\n\
C> gdb \n");

  }
  iov = async->iov;
  outportb(com_ier, 0x0f);
  outportb(com_bfr, 0x03);
  outportb(com_mcr, 0x0b);
  async->getp = async->putp = async->buffer_start;
  
  if (iov > 0x300)
    return 1;
  else
    return 2;
}

static void
dos_async_tx(c)
     const char c;
{
  while (~inportb(com_lsr) & 0x20);

  outportb(com_tb, c);
}

static int
dos_async_ready()
{
  return (async->getp != async->putp);
}

static int
dos_async_rx()
{
  char rv;

  while (!dos_async_ready())
    if (kbhit())
      {
	printf("abort!\n");
	return 0;
      }

  rv = *aptr(async->getp++);
  if (async->getp >= async->buffer_end)
    async->getp = async->buffer_start;

  return rv;
}

static int
dosasync_read (fd, buf, len, timeout)
     int fd;
     char *buf;
     int len;
     int timeout;
{
  long now, then;
  int l = len;

  time (&now);
  then = now + timeout;

  while (l--)
    {
      if (timeout)
	{
	  while (!dos_async_ready())
	    {
	      time (&now);
	      if (now >= then)
		return len - l - 1;
	    }
	}
      *buf++ = dos_async_rx();
    }

  return len;
}

static int
dosasync_write(fd, buf, len)
     int fd;
     const char *buf;
     int len;
{
  int l = len;

  while (l--)
    dos_async_tx (*buf++);

  return len;
}

static int
go32_open (scb, name)
     serial_t scb;
     const char *name;
{
  scb->fd = dos_async_init();
  if (scb->fd)
    return 1;

  return 0;
}

static void
go32_raw (scb)
     serial_t scb;
{
  /* Always in raw mode */
}

static int
go32_readchar (scb, timeout)
     serial_t scb;
     int timeout;
{
  char buf;

  if (dosasync_read(scb->fd, &buf, 1, timeout))  
    return buf;
  else
    return -2; /* Timeout, I guess */
}

static int
go32_setbaudrate (scb, rate)
     serial_t scb;
     int rate;
{
  return 0;
}

static int
go32_write (scb, str, len)
     serial_t scb;
     const char *str;
     int len;
{
  dosasync_write(scb->fd, str, len);
}

static void
go32_close ()
{
}

static void
go32_restore (scb)
     serial_t scb;
{
}

static struct serial_ops go32_ops =
{
  "hardwire",
  0,
  go32_open,
  go32_close,
  go32_readchar,
  go32_write,
  go32_raw,
  go32_restore,
  go32_setbaudrate
};

_initialize_ser_go32 ()
{
  serial_add_interface (&go32_ops);
}