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/*
* Clock Tick Device Driver Shell
*
* COPYRIGHT (c) 1989-2006.
* 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.rtems.com/license/LICENSE.
*
* $Id$
*/
#include <stdlib.h>
#include <bsp.h>
#if defined(CLOCK_DRIVER_USE_FAST_IDLE) && defined(CLOCK_DRIVER_ISRS_PER_TICK)
#error "clockdrv_shell.c: fast idle and N ISRs per tick is not supported"
#endif
/*
* This method is rarely used so default it.
*/
#ifndef Clock_driver_support_find_timer
#define Clock_driver_support_find_timer()
#endif
/*
* ISRs until next clock tick
*/
#ifdef CLOCK_DRIVER_ISRS_PER_TICK
volatile uint32_t Clock_driver_isrs;
#endif
/*
* Clock ticks since initialization
*/
volatile uint32_t Clock_driver_ticks;
/*
* ISR formerly installed.
*/
rtems_isr_entry Old_ticker;
void Clock_exit( void );
/*
* Major and minor number.
*/
rtems_device_major_number rtems_clock_major = UINT32_MAX;
rtems_device_minor_number rtems_clock_minor;
/*
* Clock_isr
*
* This is the clock tick interrupt handler.
*
* Input parameters:
* vector - vector number
*
* Output parameters: NONE
*
* Return values: NONE
*
*/
rtems_isr Clock_isr(
rtems_vector_number vector
)
{
/*
* Accurate count of ISRs
*/
Clock_driver_ticks += 1;
#ifdef CLOCK_DRIVER_USE_FAST_IDLE
do {
rtems_clock_tick();
} while ( _Thread_Executing == _Thread_Idle &&
_Thread_Heir == _Thread_Executing);
Clock_driver_support_at_tick();
return;
#else
/*
* Do the hardware specific per-tick action.
*
* The counter/timer may or may not be set to automatically reload.
*/
Clock_driver_support_at_tick();
#ifdef CLOCK_DRIVER_ISRS_PER_TICK
/*
* The driver is multiple ISRs per clock tick.
*/
if ( !Clock_driver_isrs ) {
rtems_clock_tick();
Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK;
}
Clock_driver_isrs--;
#else
/*
* The driver is one ISR per clock tick.
*/
rtems_clock_tick();
#endif
#endif
}
/*
* Install_clock
*
* This routine actually performs the hardware initialization for the clock.
*
* Input parameters:
* clock_isr - clock interrupt service routine entry point
*
* Output parameters: NONE
*
* Return values: NONE
*
*/
static void Install_clock(
rtems_isr_entry clock_isr
)
{
Clock_driver_ticks = 0;
/*
* Find timer -- some BSPs search buses for hardware timer
*/
Clock_driver_support_find_timer();
/*
* Install vector
*/
Clock_driver_support_install_isr( clock_isr, Old_ticker );
#if defined(Clock_driver_nanoseconds_since_last_tick)
rtems_clock_set_nanoseconds_extension(
Clock_driver_nanoseconds_since_last_tick
);
#endif
/*
* Now initialize the hardware that is the source of the tick ISR.
*/
Clock_driver_support_initialize_hardware();
atexit( Clock_exit );
}
/*
* Clock_exit
*
* This routine allows the clock driver to exit by masking the interrupt and
* disabling the clock's counter.
*
* Input parameters: NONE
*
* Output parameters: NONE
*
* Return values: NONE
*
*/
void Clock_exit( void )
{
Clock_driver_support_shutdown_hardware();
/* do not restore old vector */
}
/*
* Clock_initialize
*
* This routine initializes the clock driver.
*
* Input parameters:
* major - clock device major number
* minor - clock device minor number
* parg - pointer to optional device driver arguments
*
* Output parameters: NONE
*
* Return values:
* rtems_device_driver status code
*/
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
/*
* If we are counting ISRs per tick, then initialize the counter.
*/
#ifdef CLOCK_DRIVER_ISRS_PER_TICK
Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK;
#endif
return RTEMS_SUCCESSFUL;
}
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