/********************************************************************************
* sched/timer_create.c
*
* Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
********************************************************************************/
/********************************************************************************
* Included Files
********************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <wdog.h>
#include <errno.h>
#include <nuttx/kmalloc.h>
#include "timer_internal.h"
#ifndef CONFIG_DISABLE_POSIX_TIMERS
/********************************************************************************
* Definitions
********************************************************************************/
/********************************************************************************
* Private Data
********************************************************************************/
/********************************************************************************
* Public Data
********************************************************************************/
/********************************************************************************
* Private Functions
********************************************************************************/
/********************************************************************************
* Name: timer_allocate
*
* Description:
* Allocate one POSIX timer and place it into the allocated timer list.
*
********************************************************************************/
static struct posix_timer_s *timer_allocate(void)
{
struct posix_timer_s *ret;
irqstate_t flags;
uint8_t pt_flags;
/* Try to get a preallocated timer from the free list */
#if CONFIG_PREALLOC_TIMERS > 0
flags = irqsave();
ret = (struct posix_timer_s*)sq_remfirst((sq_queue_t*)&g_freetimers);
irqrestore(flags);
/* Did we get one? */
if (ret)
{
pt_flags = PT_FLAGS_PREALLOCATED;
}
else
#endif
{
/* Allocate a new timer from the heap */
ret = (struct posix_timer_s*)kmalloc(sizeof(struct posix_timer_s));
pt_flags = 0;
}
/* If we have a timer, then put it into the allocated timer list */
if (ret)
{
/* Initialize the timer structure */
memset(ret, 0, sizeof(struct posix_timer_s));
ret->pt_flags = pt_flags;
/* And add it to the end of the list of allocated timers */
flags = irqsave();
sq_addlast((sq_entry_t*)ret, (sq_queue_t*)&g_alloctimers);
irqrestore(flags);
}
return ret;
}
/********************************************************************************
* Public Functions
********************************************************************************/
/********************************************************************************
* Name: timer_create
*
* Description:
* The timer_create() function creates per-thread timer using the specified
* clock, clock_id, as the timing base. The timer_create() function returns, in
* the location referenced by timerid, a timer ID of type timer_t used to identify
* the timer in timer requests. This timer ID is unique until the timer is
* deleted. The particular clock, clock_id, is defined in <time.h>. The timer
* whose ID is returned will be in a disarmed state upon return from
* timer_create().
*
* The evp argument, if non-NULL, points to a sigevent structure. This structure
* is allocated by the called and defines the asynchronous notification to occur.
* If the evp argument is NULL, the effect is as if the evp argument pointed to
* a sigevent structure with the sigev_notify member having the value SIGEV_SIGNAL,
* the sigev_signo having a default signal number, and the sigev_value member
* having the value of the timer ID.
*
* Each implementation defines a set of clocks that can be used as timing bases
* for per-thread timers. All implementations shall support a clock_id of
* CLOCK_REALTIME.
*
* Parameters:
* clockid - Specifies the clock to use as the timing base.
* evp - Refers to a user allocated sigevent structure that defines the
* asynchronous notification. evp may be NULL (see above).
* timerid - The pre-thread timer created by the call to timer_create().
*
* Return Value:
* If the call succeeds, timer_create() will return 0 (OK) and update the
* location referenced by timerid to a timer_t, which can be passed to the
* other per-thread timer calls. If an error occurs, the function will return
* a value of -1 (ERROR) and set errno to indicate the error.
*
* EAGAIN - The system lacks sufficient signal queuing resources to honor the
* request.
* EAGAIN - The calling process has already created all of the timers it is
* allowed by this implementation.
* EINVAL - The specified clock ID is not defined.
* ENOTSUP - The implementation does not support the creation of a timer attached
* to the CPU-time clock that is specified by clock_id and associated with a
* thread different thread invoking timer_create().
*
* Assumptions:
*
********************************************************************************/
int timer_create(clockid_t clockid, FAR struct sigevent *evp, FAR timer_t *timerid)
{
struct posix_timer_s *ret;
WDOG_ID wdog;
/* Sanity checks. Also, we support only CLOCK_REALTIME */
if (!timerid || clockid != CLOCK_REALTIME)
{
errno = EINVAL;
return ERROR;
}
/* Allocate a watchdog to provide the underling CLOCK_REALTIME timer */
wdog = wd_create();
if (!wdog)
{
errno = EAGAIN;
return ERROR;
}
/* Allocate a timer instance to contain the watchdog */
ret = timer_allocate();
if (!ret)
{
errno = EAGAIN;
return ERROR;
}
/* Initialize the timer instance */
ret->pt_crefs = 1;
ret->pt_owner = getpid();
ret->pt_delay = 0;
ret->pt_wdog = wdog;
if (evp)
{
ret->pt_signo = evp->sigev_signo;
#ifdef CONFIG_CAN_PASS_STRUCTS
ret->pt_value = evp->sigev_value;
#else
ret->pt_value.sival_ptr = evp->sigev_value.sival_ptr;
#endif
}
else
{
ret->pt_signo = SIGALRM;
ret->pt_value.sival_ptr = ret;
}
/* Return the timer */
*timerid = ret;
return OK;
}
#endif /* CONFIG_DISABLE_POSIX_TIMERS */
