146 lines
4.6 KiB
C
146 lines
4.6 KiB
C
/****************************************************************************
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* sched/wdog/wd_create.c
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*
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* Copyright (C) 2007-2009, 2014, 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdbool.h>
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#include <queue.h>
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#include <nuttx/irq.h>
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#include <nuttx/wdog.h>
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#include <nuttx/wdog.h>
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#include <nuttx/kmalloc.h>
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#include "wdog/wdog.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: wd_create
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*
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* Description:
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* The wd_create function will create a watchdog timer by allocating one
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* from the list of free watchdog timers.
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*
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* Parameters:
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* None
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*
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* Return Value:
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* Pointer to watchdog (i.e., the watchdog ID), or NULL if insufficient
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* watchdogs are available.
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*
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****************************************************************************/
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WDOG_ID wd_create (void)
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{
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FAR struct wdog_s *wdog;
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irqstate_t flags;
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/* These actions must be atomic with respect to other tasks and also with
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* respect to interrupt handlers that may be allocating or freeing watchdog
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* timers.
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*/
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flags = enter_critical_section();
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/* If we are in an interrupt handler -OR- if the number of pre-allocated
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* timer structures exceeds the reserve, then take the next timer from
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* the head of the free list.
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*/
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if (g_wdnfree > CONFIG_WDOG_INTRESERVE || up_interrupt_context())
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{
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/* Remove the watchdog timer from the free list */
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wdog = (FAR struct wdog_s *)sq_remfirst(&g_wdfreelist);
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/* Did we get one? */
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if (wdog != NULL)
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{
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/* Yes.. decrement the count of free, pre-allocated timers (all
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* with interrupts disabled).
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*/
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DEBUGASSERT(g_wdnfree > 0);
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g_wdnfree--;
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/* Clear the forward link and all flags */
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wdog->next = NULL;
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wdog->flags = 0;
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}
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else
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{
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/* We didn't get one... The count should then be exactly zero */
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DEBUGASSERT(g_wdnfree == 0);
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}
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leave_critical_section(flags);
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}
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/* We are in a normal tasking context AND there are not enough unreserved,
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* pre-allocated watchdog timers. We need to allocate one from the kernel
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* heap.
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*/
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else
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{
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/* We do not require that interrupts be disabled to do this. */
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leave_critical_section(flags);
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wdog = (FAR struct wdog_s *)kmm_malloc(sizeof(struct wdog_s));
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/* Did we get one? */
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if (wdog)
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{
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/* Yes.. Clear the forward link and set the allocated flag */
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wdog->next = NULL;
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wdog->flags = WDOGF_ALLOCED;
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}
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}
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return (WDOG_ID)wdog;
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}
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