/**************************************************************************** * arch/arm/src/stm32/stm32_oneshot.c * * Copyright (C) 2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the names NuttX nor Atmel nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include "stm32_oneshot.h" #ifdef CONFIG_STM32_ONESHOT /**************************************************************************** * Private Date ****************************************************************************/ static struct stm32_oneshot_s *g_oneshot; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: stm32_oneshot_handler * * Description: * Timer interrupt callback. When the oneshot timer interrupt expires, * this function will be called. It will forward the call to the next * level up. * * Input Parameters: * tch - The handle that represents the timer state * arg - An opaque argument provided when the interrupt was registered * sr - The value of the timer interrupt status register at the time * that the interrupt occurred. * * Returned Value: * None * ****************************************************************************/ static int stm32_oneshot_handler(int irq, void *context) { struct stm32_oneshot_s *oneshot = g_oneshot; oneshot_handler_t oneshot_handler; void *oneshot_arg; tmrinfo("Expired...\n"); DEBUGASSERT(oneshot != NULL && oneshot->handler); /* The clock was stopped, but not disabled when the RC match occurred. * Disable the TC now and disable any further interrupts. */ STM32_TIM_SETISR(oneshot->tch, NULL, 0); STM32_TIM_DISABLEINT(oneshot->tch, 0); STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_DISABLED); STM32_TIM_ACKINT(oneshot->tch, 0); /* The timer is no longer running */ oneshot->running = false; /* Forward the event, clearing out any vestiges */ oneshot_handler = (oneshot_handler_t)oneshot->handler; oneshot->handler = NULL; oneshot_arg = (void *)oneshot->arg; oneshot->arg = NULL; oneshot_handler(oneshot_arg); return OK; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: stm32_oneshot_initialize * * Description: * Initialize the oneshot timer wrapper * * Input Parameters: * oneshot Caller allocated instance of the oneshot state structure * chan Timer counter channel to be used. * resolution The required resolution of the timer in units of * microseconds. NOTE that the range is restricted to the * range of uint16_t (excluding zero). * * Returned Value: * Zero (OK) is returned on success; a negated errno value is returned * on failure. * ****************************************************************************/ int stm32_oneshot_initialize(struct stm32_oneshot_s *oneshot, int chan, uint16_t resolution) { uint32_t frequency; tmrinfo("chan=%d resolution=%d usec\n", chan, resolution); DEBUGASSERT(oneshot && resolution > 0); /* Get the TC frequency the corresponds to the requested resolution */ frequency = USEC_PER_SEC / (uint32_t)resolution; oneshot->frequency = frequency; oneshot->tch = stm32_tim_init(chan); if (!oneshot->tch) { tmrerr("ERROR: Failed to allocate TIM%d\n", chan); return -EBUSY; } STM32_TIM_SETCLOCK(oneshot->tch, frequency); /* Initialize the remaining fields in the state structure and return * success. */ oneshot->chan = chan; oneshot->running = false; oneshot->handler = NULL; oneshot->arg = NULL; g_oneshot = oneshot; return OK; } /**************************************************************************** * Name: stm32_oneshot_max_delay * * Description: * Determine the maximum delay of the one-shot timer (in microseconds) * ****************************************************************************/ int stm32_oneshot_max_delay(struct stm32_oneshot_s *oneshot, uint64_t *usec) { DEBUGASSERT(oneshot != NULL && usec != NULL); *usec = (uint64_t)(UINT32_MAX / oneshot->frequency) * (uint64_t)USEC_PER_SEC; return OK; } /**************************************************************************** * Name: stm32_oneshot_start * * Description: * Start the oneshot timer * * Input Parameters: * oneshot Caller allocated instance of the oneshot state structure. This * structure must have been previously initialized via a call to * stm32_oneshot_initialize(); * handler The function to call when when the oneshot timer expires. * arg An opaque argument that will accompany the callback. * ts Provides the duration of the one shot timer. * * Returned Value: * Zero (OK) is returned on success; a negated errno value is returned * on failure. * ****************************************************************************/ int stm32_oneshot_start(struct stm32_oneshot_s *oneshot, oneshot_handler_t handler, void *arg, const struct timespec *ts) { uint64_t usec; uint64_t period; irqstate_t flags; tmrinfo("handler=%p arg=%p, ts=(%lu, %lu)\n", handler, arg, (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec); DEBUGASSERT(oneshot && handler && ts); DEBUGASSERT(oneshot->tch); /* Was the oneshot already running? */ flags = enter_critical_section(); if (oneshot->running) { /* Yes.. then cancel it */ tmrinfo("Already running... cancelling\n"); (void)stm32_oneshot_cancel(oneshot, NULL); } /* Save the new handler and its argument */ oneshot->handler = handler; oneshot->arg = arg; /* Express the delay in microseconds */ usec = (uint64_t)ts->tv_sec * USEC_PER_SEC + (uint64_t)(ts->tv_nsec / NSEC_PER_USEC); /* Get the timer counter frequency and determine the number of counts need * to achieve the requested delay. * * frequency = ticks / second * ticks = seconds * frequency * = (usecs * frequency) / USEC_PER_SEC; */ period = (usec * (uint64_t)oneshot->frequency) / USEC_PER_SEC; tmrinfo("usec=%llu period=%08llx\n", usec, period); DEBUGASSERT(period <= UINT32_MAX); /* Set up to receive the callback when the interrupt occurs */ STM32_TIM_SETISR(oneshot->tch, stm32_oneshot_handler, 0); /* Set timer period */ oneshot->period = (uint32_t)period; STM32_TIM_SETPERIOD(oneshot->tch, (uint32_t)period); /* Start the counter */ STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_PULSE); STM32_TIM_ACKINT(oneshot->tch, 0); STM32_TIM_ENABLEINT(oneshot->tch, 0); /* Enable interrupts. We should get the callback when the interrupt * occurs. */ oneshot->running = true; leave_critical_section(flags); return OK; } /**************************************************************************** * Name: stm32_oneshot_cancel * * Description: * Cancel the oneshot timer and return the time remaining on the timer. * * NOTE: This function may execute at a high rate with no timer running (as * when pre-emption is enabled and disabled). * * Input Parameters: * oneshot Caller allocated instance of the oneshot state structure. This * structure must have been previously initialized via a call to * stm32_oneshot_initialize(); * ts The location in which to return the time remaining on the * oneshot timer. A time of zero is returned if the timer is * not running. ts may be zero in which case the time remaining * is not returned. * * Returned Value: * Zero (OK) is returned on success. A call to up_timer_cancel() when * the timer is not active should also return success; a negated errno * value is returned on any failure. * ****************************************************************************/ int stm32_oneshot_cancel(struct stm32_oneshot_s *oneshot, struct timespec *ts) { irqstate_t flags; uint64_t usec; uint64_t sec; uint64_t nsec; uint32_t count; uint32_t period; /* Was the timer running? */ flags = enter_critical_section(); if (!oneshot->running) { /* No.. Just return zero timer remaining and successful cancellation. * This function may execute at a high rate with no timer running * (as when pre-emption is enabled and disabled). */ ts->tv_sec = 0; ts->tv_nsec = 0; leave_critical_section(flags); return OK; } /* Yes.. Get the timer counter and period registers and stop the counter. * If the counter expires while we are doing this, the counter clock will * be stopped, but the clock will not be disabled. * * The expected behavior is that the the counter register will freezes at * a value equal to the RC register when the timer expires. The counter * should have values between 0 and RC in all other cased. * * REVISIT: This does not appear to be the case. */ tmrinfo("Cancelling...\n"); count = STM32_TIM_GETCOUNTER(oneshot->tch); period = oneshot->period; /* Now we can disable the interrupt and stop the timer. */ STM32_TIM_DISABLEINT(oneshot->tch, 0); STM32_TIM_SETISR(oneshot->tch, NULL, 0); STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_DISABLED); oneshot->running = false; oneshot->handler = NULL; oneshot->arg = NULL; leave_critical_section(flags); /* Did the caller provide us with a location to return the time * remaining? */ if (ts) { /* Yes.. then calculate and return the time remaining on the * oneshot timer. */ tmrinfo("period=%lu count=%lu\n", (unsigned long)period, (unsigned long)count); /* REVISIT: I am not certain why the timer counter value sometimes * exceeds RC. Might be a bug, or perhaps the counter does not stop * in all cases. */ if (count >= period) { /* No time remaining (?) */ ts->tv_sec = 0; ts->tv_nsec = 0; } else { /* The total time remaining is the difference. Convert the that * to units of microseconds. * * frequency = ticks / second * seconds = ticks * frequency * usecs = (ticks * USEC_PER_SEC) / frequency; */ usec = (((uint64_t)(period - count)) * USEC_PER_SEC) / oneshot->frequency; /* Return the time remaining in the correct form */ sec = usec / USEC_PER_SEC; nsec = ((usec) - (sec * USEC_PER_SEC)) * NSEC_PER_USEC; ts->tv_sec = (time_t)sec; ts->tv_nsec = (unsigned long)nsec; } tmrinfo("remaining (%lu, %lu)\n", (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec); } return OK; } #endif /* CONFIG_STM32_ONESHOT */