detectxp1541.c

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/*
 *      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.
 *
 *  Copyright 2005 Spiro Trikaliotis
 *  Based on code by Wolfgang Moser
 *
*/

#define DBG_USERMODE

#define DBG_PROGNAME "OPENCBM.DLL"

#include "debug.h"

#include <stdlib.h>

#define DLL
#include "opencbm.h"
#include "archlib.h"

#include "arch.h"


static int
pia_to_inputmode(CBM_FILE HandleDevice, unsigned char Drive, unsigned int PiaAddress)
{
    int ret = -1;
    unsigned char byteval = 0x00;

    FUNC_ENTER();

    if (cbm_upload(HandleDevice, Drive, PiaAddress + 2, &byteval, 1) == 1)
        ret = 0;
    else
        ret = 1;

    FUNC_LEAVE_INT(ret);
}

static int
output_pia(CBM_FILE HandleDevice, unsigned char Drive, unsigned int PiaAddress, unsigned char Value)
{
    int ret = -1;

    FUNC_ENTER();

    do {
        unsigned char byteval = 0xff;

        /*
         * Set the PIA port to output
         */
        if (cbm_upload(HandleDevice, Drive, PiaAddress + 2, &byteval, 1) != 1)
            break;

        /*
         * Output the value via the PIA port
         */
        if (cbm_upload(HandleDevice, Drive, PiaAddress , &Value, 1) != 1)
            break;

        /*
         * Give the drive time to be able to execute this command
         */
        arch_usleep(10000);

        /*
         * Read back the value. Hopefully, it is exactly what we just have written.
         */
        ret = cbm_pp_read(HandleDevice) != Value;

        if (ret)
        {
            /*
             * The test was unsuccessfull. To make sure the PIA
             * is not stuck at output mode, set it back to input mode.
             */
            pia_to_inputmode(HandleDevice, Drive, PiaAddress);
        }

    } while (0);

    FUNC_LEAVE_INT(ret);
}

int CBMAPIDECL 
cbm_identify_xp1541(CBM_FILE HandleDevice, __u_char DeviceAddress,
                    enum cbm_device_type_e *CbmDeviceType,
                    enum cbm_cable_type_e *CableType)
{
    int ret = 0;
    enum cbm_device_type_e localDummyDeviceType = cbm_dt_unknown;

    FUNC_ENTER();
 
    do
    {
        unsigned int piaAddress;
        int value;

        if (!CableType)
        {
            /*
             * We do not have a possibility to send back the
             * cable type: This is an error!
             */
            DBG_ASSERT(("CableType is NULL", 0));
            ret = 1;
            break;
        }

        *CableType = cbm_ct_none;

        /*
         * If needed, determine the type of the drive
         */
        if (!CbmDeviceType)
            CbmDeviceType = &localDummyDeviceType;

        if (*CbmDeviceType == cbm_dt_unknown)
        {
            ret = cbm_identify(HandleDevice, DeviceAddress,
                 CbmDeviceType, NULL);
        }

        if (ret)
        {
            /*
             * We could not even determine the device type;
             * we do not dare trying to determine the cable
             * type, as writing into wrong locations can
             * make the drive hang.
             */
            *CableType = cbm_ct_unknown;
            break;
        }

        /*
         * Now that we know the drive type, use this to find the PIA/VIA/CIA address
         */
        switch (*CbmDeviceType)
        {
        case cbm_dt_cbm1541:
            piaAddress = 0x1801;
            break;

        case cbm_dt_cbm1570:
        case cbm_dt_cbm1571:
            piaAddress = 0x4001;
            break;

        default:
            piaAddress = 0;
            break;
        }

        /*
         * If we do not have a PIA address, we do not know where a parallel
         * cable could be located. This, report "no parallel cable".
         */
        if (piaAddress == 0)
            break;

        /*
         * Set parallel port into input mode.
         * This prevents us (PC) and the drive driving the lines simultaneously.
         */
        value = cbm_pp_read(HandleDevice);
        DBG_PRINT((DBG_PREFIX "Setting Parport into input mode", value));

        /*
         * Try to write some patterns and check if we see them:
         */
        if (output_pia(HandleDevice, DeviceAddress, piaAddress, 0x55))
            break;

        if (output_pia(HandleDevice, DeviceAddress, piaAddress, 0xAA))
            break;

        /*
         * Ok, it has worked: We have a parallel cable.
         */
        *CableType = cbm_ct_xp1541;

        /*
         * Set PIA back to input mode.
         * Again, this prevents PC and drive driving the lines simultaneously
         * (in the future).
         */
        if (piaAddress)
        {
            pia_to_inputmode(HandleDevice, DeviceAddress, piaAddress);
        }

    } while (0);

    FUNC_LEAVE_INT(ret);
}

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