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/*  Clock

 *

 *  This routine generates clock ticks using standard POSIX services.

 *  The tick frequency is specified by the bsp.

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: clock.c,v 1.2 2001-09-27 12:01:14 chris Exp $

 */

#include <bsp.h>

#include <rtems/libio.h>

#include <stdlib.h>

void Clock_exit(void);

volatile rtems_unsigned32 Clock_driver_ticks;

rtems_unsigned32 Clock_driver_vector;

/*

 * These are set by clock driver during its init

 */

rtems_device_major_number rtems_clock_major = ~0;

rtems_device_minor_number rtems_clock_minor;

void Install_clock(rtems_isr_entry clock_isr)

{

    Clock_driver_ticks = 0;

    (void) set_vector( clock_isr, Clock_driver_vector, 1 );

    _CPU_Start_clock( BSP_Configuration.microseconds_per_tick );

    atexit(Clock_exit);

}

void Clock_isr(int vector)

{

    Clock_driver_ticks++;

    rtems_clock_tick();

}

/*

 * Called via atexit()

 * Remove the clock signal

 */

void Clock_exit(void)

{

  _CPU_Stop_clock();

  (void) set_vector( 0, Clock_driver_vector, 1 );

}

rtems_device_driver Clock_initialize(

  rtems_device_major_number major,

  rtems_device_minor_number minor,

  void *pargp

)

{

    Clock_driver_vector = _CPU_Get_clock_vector();

    Install_clock((rtems_isr_entry) Clock_isr);

    /*

     * make major/minor avail to others such as shared memory driver

     */

    rtems_clock_major = major;

    rtems_clock_minor = minor;

    return RTEMS_SUCCESSFUL;

}

rtems_device_driver Clock_control(

  rtems_device_major_number major,

  rtems_device_minor_number minor,

  void *pargp

)

{

    rtems_unsigned32 isrlevel;

    rtems_libio_ioctl_args_t *args = pargp;

    if (args == 0)

        goto done;

    /*

     * This is hokey, but until we get a defined interface

     * to do this, it will just be this simple...

     */

    if (args->command == rtems_build_name('I', 'S', 'R', ' '))

    {

        Clock_isr(Clock_driver_vector);

    }

    else if (args->command == rtems_build_name('N', 'E', 'W', ' '))

    {

      rtems_interrupt_disable( isrlevel );

       (void) set_vector( args->buffer, Clock_driver_vector, 1 );

      rtems_interrupt_enable( isrlevel );

    }

done:

    return RTEMS_SUCCESSFUL;

}