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/* ckinit.c
*
* This file provides a template for the clock device driver initialization.
*
* COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
* On-Line Applications Research Corporation (OAR).
* All rights assigned to U.S. Government, 1994.
*
* This material may be reproduced by or for the U.S. Government pursuant
* to the copyright license under the clause at DFARS 252.227-7013. This
* notice must appear in all copies of this file and its derivatives.
*
* $Id$
*/
#include <stdlib.h>
#include <rtems.h>
#include <bsp.h>
#include <clockdrv.h>
/*
* The interrupt vector number associated with the clock tick device
* driver.
*/
#define CLOCK_VECTOR 4
/*
* Clock_driver_ticks is a monotonically increasing counter of the
* number of clock ticks since the driver was initialized.
*/
volatile rtems_unsigned32 Clock_driver_ticks;
/*
* Clock_isrs is the number of clock ISRs until the next invocation of
* the RTEMS clock tick routine. The clock tick device driver
* gets an interrupt once a millisecond and counts down until the
* length of time between the user configured microseconds per tick
* has passed.
*/
rtems_unsigned32 Clock_isrs; /* ISRs until next tick */
/*
* The previous ISR on this clock tick interrupt vector.
*/
rtems_isr_entry Old_ticker;
/*
* Clock_initialize
*
* Device driver entry point for clock tick driver initialization.
*/
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp,
rtems_id tid,
rtems_unsigned32 *rval
)
{
Install_clock( Clock_isr );
}
/*
* Reinstall_clock
*
* Install a clock tick handler without reprogramming the chip. This
* is used by the polling shared memory device driver.
*/
void ReInstall_clock(
rtems_isr_entry clock_isr
)
{
rtems_unsigned32 isrlevel = 0;
/*
* Disable interrupts and install the clock ISR vector using the
* BSP dependent set_vector routine. In the below example, the clock
* ISR is on vector 4 and is an RTEMS interrupt.
*/
rtems_interrupt_disable( isrlevel );
(void) set_vector( clock_isr, CLOCK_VECTOR, 1 );
rtems_interrupt_enable( isrlevel );
}
/*
* Install_clock
*
* Install a clock tick handler and reprograms the chip. This
* is used to initially establish the clock tick.
*/
void Install_clock(
rtems_isr_entry clock_isr
)
{
/*
* Initialize the clock tick device driver variables
*/
Clock_driver_ticks = 0;
Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
/*
* If ticks_per_timeslice is configured as non-zero, then the user
* wants a clock tick.
*/
if ( BSP_Configuration.ticks_per_timeslice ) {
Old_ticker = ( rtems_isr_entry ) set_vector( clock_isr, CLOCK_VECTOR, 1 );
/*
* Hardware specific initialize goes here
*/
/* XXX */
}
/*
* Schedule the clock cleanup routine to execute if the application exits.
*/
atexit( Clock_exit );
}
/*
* Clean up before the application exits
*/
void Clock_exit( void )
{
if ( BSP_Configuration.ticks_per_timeslice ) {
/* XXX: turn off the timer interrupts */
/* XXX: If necessary, restore the old vector */
}
}
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