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