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/**
* @file
*
* @brief Schedule Alarm
* @ingroup POSIXAPI
*/
/*
* COPYRIGHT (c) 1989-2008.
* 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.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <signal.h>
#include <unistd.h>
#include <rtems/score/todimpl.h>
#include <rtems/score/watchdogimpl.h>
#include <rtems/config.h>
ISR_LOCK_DEFINE( static, _POSIX_signals_Ualarm_lock, "POSIX Ualarm" )
static uint32_t _POSIX_signals_Ualarm_interval;
static void _POSIX_signals_Ualarm_TSR( Watchdog_Control *the_watchdog )
{
int status;
ISR_lock_Context lock_context;
status = kill( getpid(), SIGALRM );
#if defined(RTEMS_DEBUG)
/*
* There is no reason to think this might fail but we should be
* cautious.
*/
_Assert(status == 0);
#else
(void) status;
#endif
_ISR_lock_ISR_disable_and_acquire(
&_POSIX_signals_Ualarm_lock,
&lock_context
);
/*
* If the reset interval is non-zero, reschedule ourselves.
*/
if ( _POSIX_signals_Ualarm_interval != 0 ) {
_Watchdog_Per_CPU_insert_relative(
the_watchdog,
_Per_CPU_Get(),
_POSIX_signals_Ualarm_interval
);
}
_ISR_lock_Release_and_ISR_enable(
&_POSIX_signals_Ualarm_lock,
&lock_context
);
}
static Watchdog_Control _POSIX_signals_Ualarm_watchdog = WATCHDOG_INITIALIZER(
_POSIX_signals_Ualarm_TSR
);
static uint32_t _POSIX_signals_Ualarm_us_to_ticks( useconds_t us )
{
uint32_t us_per_tick = rtems_configuration_get_microseconds_per_tick();
return ( us + us_per_tick - 1 ) / us_per_tick;
}
useconds_t ualarm(
useconds_t useconds,
useconds_t interval
)
{
useconds_t remaining;
Watchdog_Control *the_watchdog;
ISR_lock_Context lock_context;
ISR_lock_Context lock_context2;
Per_CPU_Control *cpu;
uint64_t now;
uint32_t ticks_initial;
uint32_t ticks_interval;
the_watchdog = &_POSIX_signals_Ualarm_watchdog;
ticks_initial = _POSIX_signals_Ualarm_us_to_ticks( useconds );
ticks_interval = _POSIX_signals_Ualarm_us_to_ticks( interval );
_ISR_lock_ISR_disable_and_acquire(
&_POSIX_signals_Ualarm_lock,
&lock_context
);
cpu = _Watchdog_Get_CPU( the_watchdog );
_Watchdog_Per_CPU_acquire_critical( cpu, &lock_context2 );
now = cpu->Watchdog.ticks;
remaining = (useconds_t) _Watchdog_Cancel(
&cpu->Watchdog.Header[ PER_CPU_WATCHDOG_RELATIVE ],
the_watchdog,
now
);
if ( ticks_initial != 0 ) {
_POSIX_signals_Ualarm_interval = ticks_interval;
cpu = _Per_CPU_Get();
_Watchdog_Set_CPU( the_watchdog, cpu );
_Watchdog_Insert(
&cpu->Watchdog.Header[ PER_CPU_WATCHDOG_RELATIVE ],
the_watchdog,
now + ticks_initial
);
}
_Watchdog_Per_CPU_release_critical( cpu, &lock_context2 );
_ISR_lock_Release_and_ISR_enable(
&_POSIX_signals_Ualarm_lock,
&lock_context
);
remaining *= rtems_configuration_get_microseconds_per_tick();
return remaining;
}
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