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Diffstat (limited to 'os/rt/src/chvt.c')
| -rw-r--r-- | os/rt/src/chvt.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/os/rt/src/chvt.c b/os/rt/src/chvt.c new file mode 100644 index 000000000..d20e20d91 --- /dev/null +++ b/os/rt/src/chvt.c @@ -0,0 +1,191 @@ +/*
+ ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
+ 2011,2012,2013 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 <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @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 {
+ /* The alarm is set to the next element in the delta list.*/
+ port_timer_set_alarm(ch.vtlist.vt_lasttime +
+ ch.vtlist.vt_next->vt_delta);
+ }
+ }
+#endif /* CH_CFG_ST_TIMEDELTA > 0 */
+}
+
+/** @} */
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