192 lines
6.9 KiB
C
192 lines
6.9 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
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2011,2012,2013,2014 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file chvt.c
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* @brief Time and Virtual Timers module code.
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*
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* @addtogroup time
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* @details Time and Virtual Timers related APIs and services.
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* @{
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*/
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#include "ch.h"
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/*===========================================================================*/
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/* Module local definitions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module exported variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local variables. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module local functions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Module exported functions. */
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/*===========================================================================*/
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/**
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* @brief Virtual Timers initialization.
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* @note Internal use only.
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*
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* @notapi
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*/
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void _vt_init(void) {
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ch.vtlist.vt_next = ch.vtlist.vt_prev = (void *)&ch.vtlist;
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ch.vtlist.vt_delta = (systime_t)-1;
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#if CH_CFG_ST_TIMEDELTA == 0
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ch.vtlist.vt_systime = 0;
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#else /* CH_CFG_ST_TIMEDELTA > 0 */
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ch.vtlist.vt_lasttime = 0;
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#endif /* CH_CFG_ST_TIMEDELTA > 0 */
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}
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/**
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* @brief Enables a virtual timer.
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* @details The timer is enabled and programmed to trigger after the delay
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* specified as parameter.
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* @pre The timer must not be already armed before calling this function.
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* @note The callback function is invoked from interrupt context.
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*
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* @param[out] vtp the @p virtual_timer_t structure pointer
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* @param[in] delay the number of ticks before the operation timeouts, the
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* special values are handled as follow:
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* - @a TIME_INFINITE is allowed but interpreted as a
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* normal time specification.
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* - @a TIME_IMMEDIATE this value is not allowed.
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* .
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* @param[in] vtfunc the timer callback function. After invoking the
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* callback the timer is disabled and the structure can
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* be disposed or reused.
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* @param[in] par a parameter that will be passed to the callback
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* function
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*
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* @iclass
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*/
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void chVTDoSetI(virtual_timer_t *vtp, systime_t delay,
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vtfunc_t vtfunc, void *par) {
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virtual_timer_t *p;
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chDbgCheckClassI();
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chDbgCheck((vtp != NULL) && (vtfunc != NULL) && (delay != TIME_IMMEDIATE));
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vtp->vt_par = par;
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vtp->vt_func = vtfunc;
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p = ch.vtlist.vt_next;
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#if CH_CFG_ST_TIMEDELTA > 0 || defined(__DOXYGEN__)
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{
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systime_t now = port_timer_get_time();
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/* If the requested delay is lower than the minimum safe delta then it
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is raised to the minimum safe value.*/
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if (delay < CH_CFG_ST_TIMEDELTA)
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delay = CH_CFG_ST_TIMEDELTA;
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if (&ch.vtlist == (virtual_timers_list_t *)p) {
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/* The delta list is empty, the current time becomes the new
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delta list base time.*/
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ch.vtlist.vt_lasttime = now;
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port_timer_start_alarm(ch.vtlist.vt_lasttime + delay);
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}
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else {
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/* Now the delay is calculated as delta from the last tick interrupt
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time.*/
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delay += now - ch.vtlist.vt_lasttime;
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/* If the specified delay is closer in time than the first element
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in the delta list then it becomes the next alarm event in time.*/
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if (delay < p->vt_delta)
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port_timer_set_alarm(ch.vtlist.vt_lasttime + delay);
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}
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}
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#endif /* CH_CFG_ST_TIMEDELTA > 0 */
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/* The delta list is scanned in order to find the correct position for
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this timer. */
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while (p->vt_delta < delay) {
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delay -= p->vt_delta;
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p = p->vt_next;
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}
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/* The timer is inserted in the delta list.*/
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vtp->vt_prev = (vtp->vt_next = p)->vt_prev;
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vtp->vt_prev->vt_next = p->vt_prev = vtp;
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vtp->vt_delta = delay
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/* Special case when the timer is in last position in the list, the
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value in the header must be restored.*/;
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p->vt_delta -= delay;
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ch.vtlist.vt_delta = (systime_t)-1;
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}
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/**
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* @brief Disables a Virtual Timer.
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* @pre The timer must be in armed state before calling this function.
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*
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* @param[in] vtp the @p virtual_timer_t structure pointer
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*
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* @iclass
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*/
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void chVTDoResetI(virtual_timer_t *vtp) {
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chDbgCheckClassI();
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chDbgCheck(vtp != NULL);
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chDbgAssert(vtp->vt_func != NULL, "timer not set or already triggered");
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/* Removing the element from the delta list.*/
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vtp->vt_next->vt_delta += vtp->vt_delta;
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vtp->vt_prev->vt_next = vtp->vt_next;
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vtp->vt_next->vt_prev = vtp->vt_prev;
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vtp->vt_func = (vtfunc_t)NULL;
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/* The above code changes the value in the header when the removed element
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is the last of the list, restoring it.*/
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ch.vtlist.vt_delta = (systime_t)-1;
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#if CH_CFG_ST_TIMEDELTA > 0 || defined(__DOXYGEN__)
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{
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if (&ch.vtlist == (virtual_timers_list_t *)ch.vtlist.vt_next) {
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/* Just removed the last element in the list, alarm timer stopped.*/
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port_timer_stop_alarm();
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}
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else {
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/* The alarm is set to the next element in the delta list.*/
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port_timer_set_alarm(ch.vtlist.vt_lasttime +
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ch.vtlist.vt_next->vt_delta);
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}
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}
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#endif /* CH_CFG_ST_TIMEDELTA > 0 */
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}
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/** @} */
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