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- /****************************************************************************
- * drivers/timers/arch_alarm.c
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership. The
- * ASF licenses this file to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance with the
- * License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <nuttx/arch.h>
- #include <nuttx/clock.h>
- #include <nuttx/timers/arch_alarm.h>
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- #define CONFIG_BOARD_LOOPSPER100USEC ((CONFIG_BOARD_LOOPSPERMSEC+5)/10)
- #define CONFIG_BOARD_LOOPSPER10USEC ((CONFIG_BOARD_LOOPSPERMSEC+50)/100)
- #define CONFIG_BOARD_LOOPSPERUSEC ((CONFIG_BOARD_LOOPSPERMSEC+500)/1000)
- #define timespec_to_usec(ts) \
- ((uint64_t)(ts)->tv_sec * USEC_PER_SEC + (ts)->tv_nsec / NSEC_PER_USEC)
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- static FAR struct oneshot_lowerhalf_s *g_oneshot_lower;
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- static inline void timespec_from_usec(FAR struct timespec *ts,
- uint64_t microseconds)
- {
- ts->tv_sec = microseconds / USEC_PER_SEC;
- microseconds -= (uint64_t)ts->tv_sec * USEC_PER_SEC;
- ts->tv_nsec = microseconds * NSEC_PER_USEC;
- }
- static void udelay_accurate(useconds_t microseconds)
- {
- struct timespec now;
- struct timespec end;
- struct timespec delta;
- ONESHOT_CURRENT(g_oneshot_lower, &now);
- timespec_from_usec(&delta, microseconds);
- clock_timespec_add(&now, &delta, &end);
- while (clock_timespec_compare(&now, &end) < 0)
- {
- ONESHOT_CURRENT(g_oneshot_lower, &now);
- }
- }
- static void udelay_coarse(useconds_t microseconds)
- {
- volatile int i;
- /* We'll do this a little at a time because we expect that the
- * CONFIG_BOARD_LOOPSPERUSEC is very inaccurate during to truncation in
- * the divisions of its calculation. We'll use the largest values that
- * we can in order to prevent significant error buildup in the loops.
- */
- while (microseconds > 1000)
- {
- for (i = 0; i < CONFIG_BOARD_LOOPSPERMSEC; i++)
- {
- }
- microseconds -= 1000;
- }
- while (microseconds > 100)
- {
- for (i = 0; i < CONFIG_BOARD_LOOPSPER100USEC; i++)
- {
- }
- microseconds -= 100;
- }
- while (microseconds > 10)
- {
- for (i = 0; i < CONFIG_BOARD_LOOPSPER10USEC; i++)
- {
- }
- microseconds -= 10;
- }
- while (microseconds > 0)
- {
- for (i = 0; i < CONFIG_BOARD_LOOPSPERUSEC; i++)
- {
- }
- microseconds--;
- }
- }
- static void oneshot_callback(FAR struct oneshot_lowerhalf_s *lower,
- FAR void *arg)
- {
- struct timespec now;
- #ifdef CONFIG_SCHED_TICKLESS
- ONESHOT_CURRENT(g_oneshot_lower, &now);
- nxsched_alarm_expiration(&now);
- #else
- struct timespec delta;
- do
- {
- static uint64_t tick = 1;
- struct timespec next;
- nxsched_process_timer();
- timespec_from_usec(&next, ++tick * USEC_PER_TICK);
- ONESHOT_CURRENT(g_oneshot_lower, &now);
- clock_timespec_subtract(&next, &now, &delta);
- }
- while (delta.tv_sec == 0 && delta.tv_nsec == 0);
- ONESHOT_START(g_oneshot_lower, oneshot_callback, NULL, &delta);
- #endif
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- void up_alarm_set_lowerhalf(FAR struct oneshot_lowerhalf_s *lower)
- {
- #ifdef CONFIG_SCHED_TICKLESS
- struct timespec maxts;
- uint64_t maxticks;
- g_oneshot_lower = lower;
- ONESHOT_MAX_DELAY(g_oneshot_lower, &maxts);
- maxticks = timespec_to_usec(&maxts) / USEC_PER_TICK;
- g_oneshot_maxticks = maxticks < UINT32_MAX ? maxticks : UINT32_MAX;
- #else
- struct timespec ts;
- g_oneshot_lower = lower;
- timespec_from_usec(&ts, USEC_PER_TICK);
- ONESHOT_START(g_oneshot_lower, oneshot_callback, NULL, &ts);
- #endif
- }
- /****************************************************************************
- * Name: up_timer_gettime
- *
- * Description:
- * Return the elapsed time since power-up (or, more correctly, since
- * the archtecture-specific timer was initialized). This function is
- * functionally equivalent to:
- *
- * int clock_gettime(clockid_t clockid, FAR struct timespec *ts);
- *
- * when clockid is CLOCK_MONOTONIC.
- *
- * This function provides the basis for reporting the current time and
- * also is used to eliminate error build-up from small errors in interval
- * time calculations.
- *
- * Provided by platform-specific code and called from the RTOS base code.
- *
- * Input Parameters:
- * ts - Provides the location in which to return the up-time.
- *
- * Returned Value:
- * Zero (OK) is returned on success; a negated errno value is returned on
- * any failure.
- *
- * Assumptions:
- * Called from the normal tasking context. The implementation must
- * provide whatever mutual exclusion is necessary for correct operation.
- * This can include disabling interrupts in order to assure atomic register
- * operations.
- *
- ****************************************************************************/
- #ifdef CONFIG_CLOCK_TIMEKEEPING
- int up_timer_getcounter(FAR uint64_t *cycles)
- {
- int ret = -EAGAIN;
- if (g_oneshot_lower != NULL)
- {
- struct timespec now;
- ret = ONESHOT_CURRENT(g_oneshot_lower, &now);
- if (ret == 0)
- {
- *cycles = timespec_to_usec(&now) / USEC_PER_TICK;
- }
- }
- return ret;
- }
- void up_timer_getmask(FAR uint64_t *mask)
- {
- *mask = 0;
- if (g_oneshot_lower != NULL)
- {
- struct timespec maxts;
- uint64_t maxticks;
- ONESHOT_MAX_DELAY(g_oneshot_lower, &maxts);
- maxticks = timespec_to_usec(&maxts) / USEC_PER_TICK;
- for (; ; )
- {
- uint64_t next = (*mask << 1) | 1;
- if (next > maxticks)
- {
- break;
- }
- *mask = next;
- }
- }
- }
- #endif
- #if defined(CONFIG_SCHED_TICKLESS)
- int up_timer_gettime(FAR struct timespec *ts)
- {
- int ret = -EAGAIN;
- if (g_oneshot_lower != NULL)
- {
- ret = ONESHOT_CURRENT(g_oneshot_lower, ts);
- }
- return ret;
- }
- #endif
- /****************************************************************************
- * Name: up_alarm_cancel
- *
- * Description:
- * Cancel the alarm and return the time of cancellation of the alarm.
- * These two steps need to be as nearly atomic as possible.
- * nxsched_alarm_expiration() will not be called unless the alarm is
- * restarted with up_alarm_start().
- *
- * If, as a race condition, the alarm has already expired when this
- * function is called, then time returned is the current time.
- *
- * NOTE: This function may execute at a high rate with no timer running (as
- * when pre-emption is enabled and disabled).
- *
- * Provided by platform-specific code and called from the RTOS base code.
- *
- * Input Parameters:
- * ts - Location to return the expiration time. The current time should
- * returned if the alarm is not active. ts may be NULL in which
- * case the time is not returned.
- *
- * Returned Value:
- * Zero (OK) is returned on success. A call to up_alarm_cancel() when
- * the timer is not active should also return success; a negated errno
- * value is returned on any failure.
- *
- * Assumptions:
- * May be called from interrupt level handling or from the normal tasking
- * level. Interrupts may need to be disabled internally to assure
- * non-reentrancy.
- *
- ****************************************************************************/
- #ifdef CONFIG_SCHED_TICKLESS
- int up_alarm_cancel(FAR struct timespec *ts)
- {
- int ret = -EAGAIN;
- if (g_oneshot_lower != NULL)
- {
- ret = ONESHOT_CANCEL(g_oneshot_lower, ts);
- ONESHOT_CURRENT(g_oneshot_lower, ts);
- }
- return ret;
- }
- #endif
- /****************************************************************************
- * Name: up_alarm_start
- *
- * Description:
- * Start the alarm. nxsched_alarm_expiration() will be called when the
- * alarm occurs (unless up_alaram_cancel is called to stop it).
- *
- * Provided by platform-specific code and called from the RTOS base code.
- *
- * Input Parameters:
- * ts - The time in the future at the alarm is expected to occur. When the
- * alarm occurs the timer logic will call nxsched_alarm_expiration().
- *
- * Returned Value:
- * Zero (OK) is returned on success; a negated errno value is returned on
- * any failure.
- *
- * Assumptions:
- * May be called from interrupt level handling or from the normal tasking
- * level. Interrupts may need to be disabled internally to assure
- * non-reentrancy.
- *
- ****************************************************************************/
- #ifdef CONFIG_SCHED_TICKLESS
- int up_alarm_start(FAR const struct timespec *ts)
- {
- int ret = -EAGAIN;
- if (g_oneshot_lower != NULL)
- {
- struct timespec now;
- struct timespec delta;
- ONESHOT_CURRENT(g_oneshot_lower, &now);
- clock_timespec_subtract(ts, &now, &delta);
- ret = ONESHOT_START(g_oneshot_lower, oneshot_callback, NULL, &delta);
- }
- return ret;
- }
- #endif
- /****************************************************************************
- * Name: up_critmon_*
- *
- * Description:
- * The first interface simply provides the current time value in unknown
- * units. NOTE: This function may be called early before the timer has
- * been initialized. In that event, the function should just return a
- * start time of zero.
- *
- * Nothing is assumed about the units of this time value. The following
- * are assumed, however: (1) The time is an unsigned integer value, (2)
- * the time is monotonically increasing, and (3) the elapsed time (also
- * in unknown units) can be obtained by subtracting a start time from
- * the current time.
- *
- * The second interface simple converts an elapsed time into well known
- * units.
- ****************************************************************************/
- #ifdef CONFIG_SCHED_CRITMONITOR
- uint32_t up_critmon_gettime(void)
- {
- uint32_t ret = 0;
- if (g_oneshot_lower != NULL)
- {
- struct timespec ts;
- ONESHOT_CURRENT(g_oneshot_lower, &ts);
- ret = timespec_to_usec(&ts);
- }
- return ret;
- }
- void up_critmon_convert(uint32_t elapsed, FAR struct timespec *ts)
- {
- timespec_from_usec(ts, elapsed);
- }
- #endif
- /****************************************************************************
- * Name: up_mdelay
- *
- * Description:
- * Delay inline for the requested number of milliseconds.
- * *** NOT multi-tasking friendly ***
- *
- ****************************************************************************/
- void up_mdelay(unsigned int milliseconds)
- {
- up_udelay(USEC_PER_MSEC * milliseconds);
- }
- /****************************************************************************
- * Name: up_udelay
- *
- * Description:
- * Delay inline for the requested number of microseconds.
- *
- * *** NOT multi-tasking friendly ***
- *
- ****************************************************************************/
- void up_udelay(useconds_t microseconds)
- {
- if (g_oneshot_lower != NULL)
- {
- udelay_accurate(microseconds);
- }
- else /* Oneshot timer hasn't been initialized yet */
- {
- udelay_coarse(microseconds);
- }
- }
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