shithub: choc

ref: 074026b37ee26e78ae1c25907d2b7211b3e5fe91
dir: /opl/opl_linux.c/

//
// Copyright(C) 2005-2014 Simon Howard
//
// 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.
//
// DESCRIPTION:
//     OPL Linux interface.
//

#include "config.h"

#ifdef HAVE_IOPERM

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/io.h>

#include "opl.h"
#include "opl_internal.h"
#include "opl_timer.h"

static unsigned int opl_port_base;

static int OPL_Linux_Init(unsigned int port_base)
{
    // Try to get permissions:

    if (ioperm(port_base, 2, 1) < 0)
    {
        fprintf(stderr, "Failed to get I/O port permissions for 0x%x: %s\n",
                        port_base, strerror(errno));

        if (errno == EPERM)
        {
            fprintf(stderr,
                    "\tYou may need to run the program as root in order\n"
                    "\tto acquire I/O port permissions for OPL MIDI playback.\n");
        }

        return 0;
    }

    opl_port_base = port_base;

    // Start callback thread

    if (!OPL_Timer_StartThread())
    {
        ioperm(port_base, 2, 0);
        return 0;
    }

    return 1;
}

static void OPL_Linux_Shutdown(void)
{
    // Stop callback thread

    OPL_Timer_StopThread();

    // Release permissions

    ioperm(opl_port_base, 2, 0);
}

static unsigned int OPL_Linux_PortRead(opl_port_t port)
{
    return inb(opl_port_base + port);
}

static void OPL_Linux_PortWrite(opl_port_t port, unsigned int value)
{
    outb(value, opl_port_base + port);
}

opl_driver_t opl_linux_driver =
{
    "Linux",
    OPL_Linux_Init,
    OPL_Linux_Shutdown,
    OPL_Linux_PortRead,
    OPL_Linux_PortWrite,
    OPL_Timer_SetCallback,
    OPL_Timer_ClearCallbacks,
    OPL_Timer_Lock,
    OPL_Timer_Unlock,
    OPL_Timer_SetPaused,
    OPL_Timer_AdjustCallbacks,
};

#endif /* #ifdef HAVE_IOPERM */