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/*

 *  Clock Tick Device Driver

 *

 *  This routine utilizes the Decrementer Register common to the PPC family.

 *

 *  The tick frequency is directly programmed to the configured number of

 *  microseconds per tick.

 *

 *  COPYRIGHT (c) 1989-1997.

 *  On-Line Applications Research Corporation (OAR).

 *  Copyright assigned to U.S. Government, 1994.

 *

 *  The license and distribution terms for this file may in

 *  the file LICENSE in this distribution or at

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

 *

 *  Modified to support the MPC750.

 *  Modifications Copyright (c) 1999 Eric Valette valette@crf.canon.fr

 *

 *  $Id: c_clock.c,v 1.2 2001-09-27 12:01:24 chris Exp $

 */

#include <rtems.h>

#include <rtems/libio.h>

#include <stdlib.h>                     /* for atexit() */

#include <assert.h>

#include <libcpu/cpu.h>

#include <libcpu/c_clock.h>

/*

 *  Clock ticks since initialization

 */

volatile rtems_unsigned32 Clock_driver_ticks;

/*

 *  This is the value programmed into the count down timer.

 */

rtems_unsigned32 Clock_Decrementer_value;

/*

 * 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 clockOff(void* unused)

{

  /*

   * Nothing to do as we cannot disable all interrupts and

   * the decrementer interrupt enable is MSR_EE

   */

}

void clockOn(void* unused)

{

  PPC_Set_decrementer( Clock_Decrementer_value );

}

/*

 *  Clock_isr

 *

 *  This is the clock tick interrupt handler.

 *

 *  Input parameters:

 *    vector - vector number

 *

 *  Output parameters:  NONE

 *

 *  Return values:      NONE

 *

 */

void clockIsr()

{

  /*

   *  The driver has seen another tick.

   */

  PPC_Set_decrementer( Clock_Decrementer_value );

  Clock_driver_ticks += 1;

  /*

   *  Real Time Clock counter/timer is set to automatically reload.

   */

  rtems_clock_tick();

}

int clockIsOn(void* unused)

{

  unsigned32 msr_value;

  _CPU_MSR_GET( msr_value );

  if (msr_value & MSR_EE) return 1;

  return 0;

}

/*

 *  Clock_exit

 *

 *  This routine allows the clock driver to exit by masking the interrupt and

 *  disabling the clock's counter.

 *

 *  Input parameters:   NONE

 *

 *  Output parameters:  NONE

 *

 *  Return values:      NONE

 *

 */

void Clock_exit( void )

{

  (void) BSP_disconnect_clock_handler ();

}

/*

 *  Clock_initialize

 *

 *  This routine initializes the clock driver.

 *

 *  Input parameters:

 *    major - clock device major number

 *    minor - clock device minor number

 *    parg  - pointer to optional device driver arguments

 *

 *  Output parameters:  NONE

 *

 *  Return values:

 *    rtems_device_driver status code

 */

rtems_device_driver Clock_initialize(

  rtems_device_major_number major,

  rtems_device_minor_number minor,

  void *pargp

)

{

  Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)*

                            (BSP_Configuration.microseconds_per_tick/1000);

  if (!BSP_connect_clock_handler ()) {

    printk("Unable to initialize system clock\n");

    rtems_fatal_error_occurred(1);

  }

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

  rtems_clock_major = major;

  rtems_clock_minor = minor;

  return RTEMS_SUCCESSFUL;

} /* Clock_initialize */

/*

 *  Clock_control

 *

 *  This routine is the clock device driver control entry point.

 *

 *  Input parameters:

 *    major - clock device major number

 *    minor - clock device minor number

 *    parg  - pointer to optional device driver arguments

 *

 *  Output parameters:  NONE

 *

 *  Return values:

 *    rtems_device_driver status code

 */

rtems_device_driver Clock_control(

  rtems_device_major_number major,

  rtems_device_minor_number minor,

  void *pargp

)

{

    rtems_libio_ioctl_args_t *args = pargp;

    if (args == 0)

        goto done;

    Clock_Decrementer_value = (BSP_bus_frequency/BSP_time_base_divisor)*

      (BSP_Configuration.microseconds_per_tick/1000);

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

      clockIsr();

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

    {

      if (!BSP_connect_clock_handler ()) {

        printk("Error installing clock interrupt handler!\n");

        rtems_fatal_error_occurred(1);

      }

    }

done:

    return RTEMS_SUCCESSFUL;

}