forked from Imagelibrary/rtems
a6b2080e1c
This function is no longer supported by the standard clock driver implementation (clockimpl.h). Update #3436.
105 lines
2.2 KiB
C
105 lines
2.2 KiB
C
/*
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* This routine initializes the MC68340/349 Periodic Interval Timer
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*/
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/*
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* Based on the `gen68360' board support package, and covered by the
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* original distribution terms.
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*
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* Geoffroy Montel
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* France Telecom - CNET/DSM/TAM/CAT
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* 4, rue du Clos Courtel
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* 35512 CESSON-SEVIGNE
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* FRANCE
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*
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* e-mail: g_montel@yahoo.com
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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> /* for atexit() */
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#include <bsp.h>
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#include <m68340.h>
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#include <rtems/clockdrv.h>
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#define CLOCK_VECTOR 120 /* clock isr routine vector in the vbr */
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#define CLOCK_IRQ_LEVEL 6 /* clock isr level */
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/*
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* Clock_driver_ticks is a monotonically increasing counter of the
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* number of clock ticks since the driver was initialized.
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*/
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volatile uint32_t Clock_driver_ticks;
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/*
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* Periodic interval timer interrupt handler
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*/
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static rtems_isr
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Clock_isr (rtems_vector_number vector)
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{
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/*
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* Announce the clock tick
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*/
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Clock_driver_ticks++;
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rtems_clock_tick();
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}
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static void
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Clock_exit (void)
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{
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/*
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* Turn off periodic interval timer
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*/
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SIMPITR = 0;
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}
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static void
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Install_clock (rtems_isr_entry clock_isr)
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{
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uint32_t pitr_tmp;
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uint32_t usecs_per_tick;
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Clock_driver_ticks = 0;
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set_vector (clock_isr, CLOCK_VECTOR, 1);
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/* sets the Periodic Interrupt Control Register PICR */
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SIMPICR = ( CLOCK_IRQ_LEVEL << 8 ) | ( CLOCK_VECTOR );
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/* sets the PITR count value */
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/* this assumes a 32.765 kHz crystal */
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usecs_per_tick = rtems_configuration_get_microseconds_per_tick();
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/* find out whether prescaler should be enabled or not */
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if ( usecs_per_tick <= 31128 ) {
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pitr_tmp = ( usecs_per_tick * 8192 ) / 1000000 ;
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} else {
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pitr_tmp = ( usecs_per_tick / 1000000 ) * 16;
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/* enable it */
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pitr_tmp |= 0x100;
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}
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SIMPITR = (unsigned char) pitr_tmp;
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atexit (Clock_exit);
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}
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rtems_device_driver
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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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