Subversion Repositories openrisc_me

/*  timer.c

 *

 *  NOTE: These routines will not work if the optimizer is enabled

 *        for some compilers.  The multiple writes to the Z8036

 *        may be optimized away.

 *

 *        It is important that the timer start/stop overhead be

 *        determined when porting or modifying this code.

 *

 *  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: timer.c,v 1.2 2001-09-27 12:00:01 chris Exp $

 */

#include <rtems.h>

#include <bsp.h>

int Ttimer_val;

rtems_boolean Timer_driver_Find_average_overhead;

rtems_isr timerisr();

void Timer_initialize()

{

  rtems_unsigned8 data;

  (void) set_vector( timerisr, TIMER_VECTOR, 0 );  /* install ISR */

  Ttimer_val = 0;                          /* clear timer ISR count */

  Z8x36_READ ( TIMER, MASTER_INTR, data );

  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x01) );

  Z8x36_WRITE( TIMER, MASTER_CFG, 0xd4 );

  Z8x36_READ ( TIMER, MASTER_INTR, data );

  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x7E) );

  Z8x36_WRITE( TIMER, CT1_TIME_CONST_MSB, 0x00 );

  Z8x36_WRITE( TIMER, CT1_TIME_CONST_LSB, 0x00 );

  Z8x36_WRITE( TIMER, CT1_MODE_SPEC, 0x87 );

  Z8x36_WRITE( TIMER, CNT_TMR_VECTOR, TIMER_VECTOR );

  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0x20 );

  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0x26 );

  Z8x36_READ ( TIMER, MASTER_INTR, data );

  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0xDA) | 0x80 );

  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0xC6 );

  /*

   * ACC_IC54 - interrupt 5 will be vectored and mapped to level 6

   */

  data = (*(rtems_unsigned8 *)0x0D00000B);

  (*(rtems_unsigned8 *)0x0D00000B) = (data & 0x0F) | 0x60;

}

#define AVG_OVERHEAD      9  /* It typically takes 3.65 microseconds */

                             /* (9 countdowns) to start/stop the timer. */

#define LEAST_VALID       10 /* Don't trust a value lower than this */

int Read_timer()

{

  rtems_unsigned8 data;

  rtems_unsigned8  msb, lsb;

  rtems_unsigned32 remaining, total;

  Z8x36_WRITE( TIMER, CT1_CMD_STATUS,  0xce ); /* read the counter value */

  Z8x36_READ(  TIMER, CT1_CUR_CNT_MSB, msb );

  Z8x36_READ(  TIMER, CT1_CUR_CNT_LSB, lsb );

  remaining = 0x10000 - ((msb << 8) + lsb);

  total = (Ttimer_val * 0x10000) + remaining;

  Z8x36_READ ( TIMER, MASTER_INTR, data );

  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x01) );

  /* do not restore old vector */

  if ( Timer_driver_Find_average_overhead == 1 )

    return total;          /* in countdown units */

  if ( total < LEAST_VALID )

    return 0;            /* below timer resolution */

  /* Clocked at 2.4615 Mhz */

  return (int)(((float)(total-AVG_OVERHEAD)) / 2.4615 * 2.0);

}

rtems_status_code Empty_function( void )

{

  return RTEMS_SUCCESSFUL;

}

void Set_find_average_overhead(

  rtems_boolean find_flag

)

{

  Timer_driver_Find_average_overhead = find_flag;

}