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/*  Clock_init()

 *

 *

 *  This is modified by Doug McBride to get it to work for the MC68EC040

 *  IDP board.  The below comments are kept to show that some prior work

 *  was done in the area and the modifications performed was application

 *  specific for the IDP board to port it to.

 *

 *  This routine initializes the mc68230 on the MC68EC040 board.

 *  The tick frequency is 40 milliseconds.

 *

 *  Input parameters:  NONE

 *

 *  Output parameters:  NONE

 *

 *  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: ckinit.c,v 1.2 2001-09-27 12:00:09 chris Exp $

 */

#include <stdlib.h>

#include <bsp.h>

#include <rtems/libio.h>

rtems_unsigned32 Clock_isrs;        /* ISRs until next tick */

volatile rtems_unsigned32 Clock_driver_ticks;

                                    /* ticks since initialization */

rtems_isr_entry  Old_ticker;

extern rtems_configuration_table Configuration;

extern void led_putnum();

void Disable_clock();

#define CLOCK_VECTOR 0x4D

void Clock_exit( void );

/*

 * These are set by clock driver during its init

 */

rtems_device_major_number rtems_clock_major = ~0;

rtems_device_minor_number rtems_clock_minor;

/*

 *  ISR Handler

 *

 *

 * ((1ms * 6.5 MHz) / 2^5) = 203.125) where 6.5 MHz is the clock rate of the

 * MC68230, 2^5 is the prescaler factor, and 1ms is the common interrupt

 * interval for the Clock_isr routine.

 * Therefore, 203 (decimal) is the number to program into the CPRH-L registers

 * of the MC68230 for countdown.  However, I have found that 193 instead of

 * 203 provides greater accuracy -- why?  The crystal should be more accurate

 * than that

 */

rtems_isr Clock_isr(

  rtems_vector_number vector

)

{

  Clock_driver_ticks += 1;

  /* acknowledge interrupt

        TSR = 1; */

  MC68230_WRITE (TSR, 1);

  if ( Clock_isrs == 1 ) {

    rtems_clock_tick();

        /* Cast to an integer so that 68EC040 IDP which doesn't have an FPU doesn't

           have a heart attack -- if you use newlib1.6 or greater and get

           libgcc.a for gcc with software floating point support, this is not

           a problem */

    Clock_isrs =

      (int)(BSP_Configuration.microseconds_per_tick / 1000);

  }

  else

    Clock_isrs -= 1;

}

void Disable_clock()

{

        /* Disable timer */

        MC68230_WRITE (TCR, 0x00);

}

void Install_clock( clock_isr )

rtems_isr_entry clock_isr;

{

  Clock_driver_ticks = 0;

  Clock_isrs = (int)(Configuration.microseconds_per_tick / 1000);

/*    led_putnum('c'); * for debugging purposes */

    Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );

  /* Disable timer for initialization */

  MC68230_WRITE (TCR, 0x00);

  /* some PI/T initialization stuff here -- see comment in the ckisr.c

     file in this directory to understand why I use the values that I do */

  /* Set up the interrupt vector on the MC68230 chip:

  TIVR = CLOCK_VECTOR; */

  MC68230_WRITE (TIVR, CLOCK_VECTOR);

  /* Set CPRH through CPRL to 193 (not 203) decimal for countdown--see ckisr.c

        CPRH = 0x00;

        CPRM = 0x00;

        CPRL = 0xC1; */

  MC68230_WRITE (CPRH, 0x00);

  MC68230_WRITE (CPRM, 0x00);

  MC68230_WRITE (CPRL, 0xC1);

  /* Enable timer and use it as an external periodic interrupt generator

        TCR = 0xA1; */

/*    led_putnum('a'); * for debugging purposes */

  MC68230_WRITE (TCR, 0xA1);

  /*

   *  Schedule the clock cleanup routine to execute if the application exits.

   */

  atexit( Clock_exit );

}

/* The following was added for debugging purposes */

void Clock_exit( void )

{

  rtems_unsigned8 data;

  /* disable timer

        data = TCR;

        TCR = (data & 0xFE); */

  MC68230_READ (TCR, data);

  MC68230_WRITE (TCR, (data & 0xFE));

  /* do not restore old vector */

}

rtems_device_driver Clock_initialize(

  rtems_device_major_number major,

  rtems_device_minor_number minor,

  void *pargp

)

{

  Install_clock( 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_VECTOR);

    }

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

    {

      rtems_interrupt_disable( isrlevel );

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

      rtems_interrupt_enable( isrlevel );

    }

done:

    return RTEMS_SUCCESSFUL;

}