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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;
}