forked from Imagelibrary/rtems
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
/*
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* This routine initailizes the periodic interrupt timer on
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* the Motorola 68332.
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*/
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/*
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* COPYRIGHT (c) 1989-2014.
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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.rtems.org/license/LICENSE.
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*/
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#include <stdlib.h>
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#include <bsp.h>
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#include <mrm332.h>
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#include <rtems/clockdrv.h>
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#include <rtems/m68k/sim.h>
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#define CLOCK_VECTOR MRM_PIV
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uint32_t Clock_isrs; /* ISRs until next tick */
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volatile uint32_t Clock_driver_ticks; /* ticks since initialization */
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static rtems_isr_entry Old_ticker;
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void Clock_exit( void );
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static rtems_isr Clock_isr(rtems_vector_number vector)
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{
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Clock_driver_ticks += 1;
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if ( Clock_isrs == 1 ) {
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rtems_clock_tick();
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Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
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}
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else
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Clock_isrs -= 1;
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}
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static void Install_clock(rtems_isr_entry clock_isr)
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{
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Clock_driver_ticks = 0;
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Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
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Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
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/* enable 1mS interrupts */
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*PITR = (unsigned short int)( SAM(0x09,0,PITM) );/* load counter */
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*PICR = (unsigned short int) /* enable interrupt */
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( SAM(ISRL_PIT,8,PIRQL) | SAM(CLOCK_VECTOR,0,PIV) );
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atexit( Clock_exit );
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}
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void Clock_exit( void )
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{
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/* shutdown the periodic interrupt */
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*PICR = (unsigned short int)
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( SAM(0,8,PIRQL) | SAM(CLOCK_VECTOR,0,PIV) );
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/* ^^ zero disables interrupt */
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/* do not restore old vector */
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}
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rtems_device_driver Clock_initialize(
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rtems_device_major_number major,
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rtems_device_minor_number minor,
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void *pargp
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)
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{
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Install_clock( Clock_isr );
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return RTEMS_SUCCESSFUL;
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}
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