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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [m68k/] [dmv152/] [timer/] [timer.c] - Blame information for rev 173

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1 30 unneback
/*  timer.c
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 *
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 *  NOTE: These routines will not work if the optimizer is enabled
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 *        for some compilers.  The multiple writes to the Z8036
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 *        may be optimized away.
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 *
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 *        It is important that the timer start/stop overhead be
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 *        determined when porting or modifying this code.
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 *
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 *  COPYRIGHT (c) 1989-1999.
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 *  On-Line Applications Research Corporation (OAR).
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 *
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 *  The license and distribution terms for this file may be
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 *  found in the file LICENSE in this distribution or at
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 *  http://www.OARcorp.com/rtems/license.html.
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 *
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 *  $Id: timer.c,v 1.2 2001-09-27 12:00:01 chris Exp $
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 */
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#include <rtems.h>
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#include <bsp.h>
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int Ttimer_val;
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rtems_boolean Timer_driver_Find_average_overhead;
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rtems_isr timerisr();
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void Timer_initialize()
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{
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  rtems_unsigned8 data;
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  (void) set_vector( timerisr, TIMER_VECTOR, 0 );  /* install ISR */
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  Ttimer_val = 0;                          /* clear timer ISR count */
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  Z8x36_READ ( TIMER, MASTER_INTR, data );
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  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x01) );
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  Z8x36_WRITE( TIMER, MASTER_CFG, 0xd4 );
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  Z8x36_READ ( TIMER, MASTER_INTR, data );
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  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x7E) );
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  Z8x36_WRITE( TIMER, CT1_TIME_CONST_MSB, 0x00 );
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  Z8x36_WRITE( TIMER, CT1_TIME_CONST_LSB, 0x00 );
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  Z8x36_WRITE( TIMER, CT1_MODE_SPEC, 0x87 );
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  Z8x36_WRITE( TIMER, CNT_TMR_VECTOR, TIMER_VECTOR );
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  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0x20 );
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  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0x26 );
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  Z8x36_READ ( TIMER, MASTER_INTR, data );
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  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0xDA) | 0x80 );
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  Z8x36_WRITE( TIMER, CT1_CMD_STATUS, 0xC6 );
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  /*
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   * ACC_IC54 - interrupt 5 will be vectored and mapped to level 6
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   */
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  data = (*(rtems_unsigned8 *)0x0D00000B);
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  (*(rtems_unsigned8 *)0x0D00000B) = (data & 0x0F) | 0x60;
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}
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#define AVG_OVERHEAD      9  /* It typically takes 3.65 microseconds */
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                             /* (9 countdowns) to start/stop the timer. */
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#define LEAST_VALID       10 /* Don't trust a value lower than this */
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int Read_timer()
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{
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  rtems_unsigned8 data;
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  rtems_unsigned8  msb, lsb;
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  rtems_unsigned32 remaining, total;
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  Z8x36_WRITE( TIMER, CT1_CMD_STATUS,  0xce ); /* read the counter value */
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  Z8x36_READ(  TIMER, CT1_CUR_CNT_MSB, msb );
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  Z8x36_READ(  TIMER, CT1_CUR_CNT_LSB, lsb );
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  remaining = 0x10000 - ((msb << 8) + lsb);
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  total = (Ttimer_val * 0x10000) + remaining;
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  Z8x36_READ ( TIMER, MASTER_INTR, data );
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  Z8x36_WRITE( TIMER, MASTER_INTR, (data & 0x01) );
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  /* do not restore old vector */
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  if ( Timer_driver_Find_average_overhead == 1 )
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    return total;          /* in countdown units */
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  if ( total < LEAST_VALID )
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    return 0;            /* below timer resolution */
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  /* Clocked at 2.4615 Mhz */
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  return (int)(((float)(total-AVG_OVERHEAD)) / 2.4615 * 2.0);
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}
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rtems_status_code Empty_function( void )
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{
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  return RTEMS_SUCCESSFUL;
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}
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void Set_find_average_overhead(
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  rtems_boolean find_flag
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)
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{
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  Timer_driver_Find_average_overhead = find_flag;
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}

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