/*****************************************************************************/
/*                                                                           */
/*                                ser_load.c                                 */
/*                                                                           */
/*                     Loader module for serial drivers                      */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2003-2006, Ullrich von Bassewitz                                      */
/*                Römerstrasse 52                                            */
/*                D-70794 Filderstadt                                        */
/* EMail:         uz@cc65.org                                                */
/*                                                                           */
/*                                                                           */
/* This software is provided 'as-is', without any expressed or implied       */
/* warranty.  In no event will the authors be held liable for any damages    */
/* arising from the use of this software.                                    */
/*                                                                           */
/* Permission is granted to anyone to use this software for any purpose,     */
/* including commercial applications, and to alter it and redistribute it    */
/* freely, subject to the following restrictions:                            */
/*                                                                           */
/* 1. The origin of this software must not be misrepresented; you must not   */
/*    claim that you wrote the original software. If you use this software   */
/*    in a product, an acknowledgment in the product documentation would be  */
/*    appreciated but is not required.                                       */
/* 2. Altered source versions must be plainly marked as such, and must not   */
/*    be misrepresented as being the original software.                      */
/* 3. This notice may not be removed or altered from any source              */
/*    distribution.                                                          */
/*                                                                           */
/*****************************************************************************/



#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <modload.h>
#include <serial.h>



/*****************************************************************************/
/*     	      	    	  	     Data	     			     */
/*****************************************************************************/



/* Pointer to serial driver, exported from ser-kernel.s */
extern void* ser_drv;

/* Function that clears the driver pointer (ser-kernel.s) */
void ser_clear_ptr (void);



/*****************************************************************************/
/*     	      	    	  	     Code	     			     */
/*****************************************************************************/



/* Use static local variables, since the module is not reentrant anyway */
#pragma staticlocals (on);



unsigned char __fastcall__ ser_load_driver (const char* name)
/* Load a serial driver and return an error code */
{
    static struct mod_ctrl ctrl = {
        read            /* Read from disk */
    };
    unsigned char Res;

    /* Check if we do already have a driver loaded. If so, remove it. */
    if (ser_drv != 0) {
        ser_uninstall ();
    }

    /* Now open the file */
    ctrl.callerdata = open (name, O_RDONLY);
    if (ctrl.callerdata >= 0) {

        /* Load the module */
        Res = mod_load (&ctrl);

        /* Close the input file */
        close (ctrl.callerdata);

        /* Check the return code */
        if (Res == MLOAD_OK) {

            /* Check the driver signature, install the driver */
            Res = ser_install (ctrl.module);

	    /* If the driver did not install correctly, remove it from
	     * memory again.
	     */
	    if (Res != SER_ERR_OK) {
                /* Do not call ser_uninstall here, since the driver is not
                 * correctly installed.
                 */
                mod_free (ser_drv);
                ser_clear_ptr ();
            }

            /* Return the error code */
            return Res;
        }
    }

    /* Error loading the driver */
    return SER_ERR_CANNOT_LOAD;
}