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Diffstat (limited to 'os/kernel/src/chtm.c')
| -rw-r--r-- | os/kernel/src/chtm.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/os/kernel/src/chtm.c b/os/kernel/src/chtm.c new file mode 100644 index 000000000..a42223da3 --- /dev/null +++ b/os/kernel/src/chtm.c @@ -0,0 +1,197 @@ +/*
+ 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 chtm.c
+ * @brief Time Measurement module code.
+ *
+ * @addtogroup time_measurement
+ * @details Time Measurement APIs and services.
+ * @{
+ */
+
+#include "ch.h"
+
+#if CH_CFG_USE_TM || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module local definitions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported variables. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local types. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local variables. */
+/*===========================================================================*/
+
+/**
+ * @brief Subsystem calibration value.
+ */
+static rtcnt_t measurement_offset;
+
+/*===========================================================================*/
+/* Module local functions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Initializes the realtime counter unit.
+ *
+ * @init
+ */
+void _rt_init(void) {
+ time_measurement_t tm;
+
+ /* Time Measurement subsystem calibration, it does a null measurement
+ and calculates the call overhead which is subtracted to real
+ measurements.*/
+ measurement_offset = 0;
+ chRTTimeMeasurementObjectInit(&tm);
+ chRTTimeMeasurementStartX(&tm);
+ chRTTimeMeasurementStopX(&tm);
+ measurement_offset = tm.last;
+}
+
+/**
+ * @brief Realtime window test.
+ * @details This function verifies if the current realtime counter value
+ * lies within the specified range or not. The test takes care
+ * of the realtime counter wrapping to zero on overflow.
+ * @note When start==end then the function returns always true because the
+ * whole time range is specified.
+ * @note This function can be called from any context.
+ *
+ * @par Example 1
+ * Example of a guarded loop using the realtime counter. The loop implements
+ * a timeout after one second.
+ * @code
+ * rtcnt_t start = chSysGetRealtimeCounterX();
+ * rtcnt_t timeout = start + S2RTC(RTCCLK, 1);
+ * while (my_condition) {
+ * if (!chTMIsCounterWithin(start, timeout)
+ * return TIMEOUT;
+ * // Do something.
+ * }
+ * // Continue.
+ * @endcode
+ *
+ * @par Example 2
+ * Example of a loop that lasts exactly 50 microseconds.
+ * @code
+ * rtcnt_t start = chSysGetRealtimeCounterX();
+ * rtcnt_t timeout = start + US2RTC(RTCCLK, 50);
+ * while (chTMIsCounterWithin(start, timeout)) {
+ * // Do something.
+ * }
+ * // Continue.
+ * @endcode
+ *
+ * @param[in] start the start of the time window (inclusive)
+ * @param[in] end the end of the time window (non inclusive)
+ * @retval true current time within the specified time window.
+ * @retval false current time not within the specified time window.
+ *
+ * @special
+ */
+bool chTMIsCounterWithin(rtcnt_t start, rtcnt_t end) {
+ rtcnt_t now = chSysGetRealtimeCounterX();
+
+ return end > start ? (now >= start) && (now < end) :
+ (now >= start) || (now < end);
+}
+
+/**
+ * @brief Polled delay.
+ * @note The real delay is always few cycles in excess of the specified
+ * value.
+ * @note This function can be called from any context.
+ *
+ * @param[in] cycles number of cycles
+ *
+ * @special
+ */
+void chTMPolledDelay(rtcnt_t cycles) {
+ rtcnt_t start = chSysGetRealtimeCounterX();
+ rtcnt_t end = start + cycles;
+ while (chRTIsCounterWithin(start, end))
+ ;
+}
+
+/**
+ * @brief Initializes a @p TimeMeasurement object.
+ *
+ * @param[out] tmp pointer to a @p TimeMeasurement structure
+ *
+ * @init
+ */
+void chTMObjectInit(time_measurement_t *tmp) {
+
+ tmp->best = (rtcnt_t)-1;
+ tmp->worst = (rtcnt_t)0;
+ tmp->cumulative = (rtcnt_t)0;
+ tmp->last = (rtcnt_t)0;
+}
+
+/**
+ * @brief Starts a measurement.
+ * @pre The @p time_measurement_t structure must be initialized.
+ * @note This function can be invoked from any context.
+ *
+ * @param[in,out] tmp pointer to a @p TimeMeasurement structure
+ *
+ * @special
+ */
+NOINLINE void chTMStartX(time_measurement_t *tmp) {
+
+ tmp->last = chSysGetRealtimeCounterX();
+}
+
+/**
+ * @brief Stops a measurement.
+ * @pre The @p time_measurement_t structure must be initialized.
+ * @note This function can be invoked from any context.
+ *
+ * @param[in,out] tmp pointer to a @p time_measurement_t structure
+ *
+ * @special
+ */
+NOINLINE void chTMStopX(time_measurement_t *tmp) {
+
+ rtcnt_t now = chSysGetRealtimeCounterX();
+ tmp->last = now - tmp->last - measurement_offset;
+ tmp->cumulative += tmp->last;
+ if (tmp->last > tmp->worst)
+ tmp->worst = tmp->last;
+ else if (tmp->last < tmp->best)
+ tmp->best = tmp->last;
+}
+
+#endif /* CH_CFG_USE_TM */
+
+/** @} */
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