/* -------------------------------------------------- 
 |  NAME
 |    devices
 |  PURPOSE
 |    handle exec devices in a standard way.
 |  NOTES
 | 
 |  COPYRIGHT
 |    Copyright (C) 1993  Christian E. Hopps
 |
 |    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.
 |    
 |  HISTORY
 |    chopps - Oct 9, 1993: Created.
 +--------------------------------------------------- */

#include "util.h"
#include "devices.h"

/* returns structure with device open. */
struct device_data *
alloc_device (char *name, ulong unit, ulong flags, ulong iosize)
{
    struct device_data *dd = zmalloc (sizeof (*dd));
    if (NULL == dd) {
	return (NULL);
    }
    dd->port = CreateMsgPort ();
    if (NULL == dd->port) {
	free_device (dd);
	return (NULL);
    }
    dd->io = CreateIORequest (dd->port, iosize);
    if (NULL == dd->io) {
	free_device (dd);
	return (NULL);
    }
    dd->name = copy_string (name);
    if (NULL == dd->name) {
	free_device (dd);
	return (NULL);
    }
    dd->unit = unit;
    dd->flags = flags;

    if (open_device (dd)) {
	free_device (dd);
	return (NULL);
    }
      
    return (dd);
}

void
free_device (struct device_data *dd)
{
    if (dd) {
	close_device (dd);
	DeleteIORequest (dd->io);
	DeleteMsgPort (dd->port);
	zfree (dd->name);	
    }
}

int
open_device (struct device_data *dd)
{
    int error = -1;
    if (dd && !dd->open) {
	error = OpenDevice (dd->name, dd->unit, dd->io, dd->flags);
	if (!error) {
	    dd->open = 1;
	} else {
	    if (-1 != error) {
		D(debug_message ("warn: unable to open \"%s\" unit: %ld flags 0x%lx",
				 dd->name, dd->unit, dd->flags));
		D(debug_message ("      reason: error %ld", error));
	    }
	    dd->open = 0;
	}
    }
    return (error);
}

void
close_device (struct device_data *dd)
{
    if (dd) {
	if (dd->open) {
	    if(!CheckIO (dd->io)) {
		AbortIO (dd->io);
		WaitIO (dd->io);
	    }
	    CloseDevice (dd->io);
	    dd->open = 0;
	}
    }
}

/* returns actual number of bytes written or -1 for error. */
ulong
device_read (struct device_data *dd, ulong offset, ulong bytes, void *buffer)
{
    struct IOStdReq *io = (struct IOStdReq *)dd->io;
    io->io_Length = bytes;
    io->io_Offset = offset;
    io->io_Data = buffer;

    if (!device_do_command (dd, CMD_READ)) {
	return (io->io_Actual);
    }
    return (-1);
}

/* returns actual number of bytes written or -1 for error. */
ulong
device_write (struct device_data *dd, ulong offset, ulong bytes, void *buffer)
{
    struct IOStdReq *io = (struct IOStdReq *)dd->io;
    io->io_Length = bytes;
    io->io_Offset = offset;
    io->io_Data = buffer;
    if (!device_do_command (dd, CMD_WRITE)) {
	return (io->io_Actual);
    }
    return (-1);
}

/* returns the error from DoIO () */
int
device_do_command (struct device_data *dd, UWORD command)
{
    int error = -1;
    if (dd) {
	if (dd->open) {
	    dd->io->io_Command = command;
	    error = (int) DoIO (dd->io);
	} else {
	    dd->io->io_Error = -1;
	}
    }
    return (error);
}