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- /****************************************************************************
- * sched/wdog/wd_create.c
- *
- * Copyright (C) 2007-2009, 2014, 2016 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 <stdbool.h>
- #include <queue.h>
- #include <nuttx/irq.h>
- #include <nuttx/wdog.h>
- #include <nuttx/wdog.h>
- #include <nuttx/kmalloc.h>
- #include "wdog/wdog.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: wd_create
- *
- * Description:
- * The wd_create function will create a watchdog timer by allocating one
- * from the list of free watchdog timers.
- *
- * Input Parameters:
- * None
- *
- * Returned Value:
- * Pointer to watchdog (i.e., the watchdog ID), or NULL if insufficient
- * watchdogs are available.
- *
- ****************************************************************************/
- WDOG_ID wd_create (void)
- {
- FAR struct wdog_s *wdog;
- irqstate_t flags;
- /* These actions must be atomic with respect to other tasks and also with
- * respect to interrupt handlers that may be allocating or freeing watchdog
- * timers.
- */
- flags = enter_critical_section();
- /* If we are in an interrupt handler -OR- if the number of pre-allocated
- * timer structures exceeds the reserve, then take the next timer from
- * the head of the free list.
- */
- if (g_wdnfree > CONFIG_WDOG_INTRESERVE || up_interrupt_context())
- {
- /* Remove the watchdog timer from the free list */
- wdog = (FAR struct wdog_s *)sq_remfirst(&g_wdfreelist);
- /* Did we get one? */
- if (wdog != NULL)
- {
- /* Yes.. decrement the count of free, pre-allocated timers (all
- * with interrupts disabled).
- */
- DEBUGASSERT(g_wdnfree > 0);
- g_wdnfree--;
- /* Clear the forward link and all flags */
- wdog->next = NULL;
- wdog->flags = 0;
- }
- else
- {
- /* We didn't get one... The count should then be exactly zero */
- DEBUGASSERT(g_wdnfree == 0);
- }
- leave_critical_section(flags);
- }
- /* We are in a normal tasking context AND there are not enough unreserved,
- * pre-allocated watchdog timers. We need to allocate one from the kernel
- * heap.
- */
- else
- {
- /* We do not require that interrupts be disabled to do this. */
- leave_critical_section(flags);
- wdog = (FAR struct wdog_s *)kmm_malloc(sizeof(struct wdog_s));
- /* Did we get one? */
- if (wdog)
- {
- /* Yes.. Clear the forward link and set the allocated flag */
- wdog->next = NULL;
- wdog->flags = WDOGF_ALLOCED;
- }
- }
- return (WDOG_ID)wdog;
- }
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