bacnet_stack/ports/xplained/ASF/xmega/services/timeout/timeout.c

/**
 * \file  timeout.c
 *
 * \brief Timeout service for XMEGA
 *
 * Copyright (C) 2011-2012 Atmel Corporation. All rights reserved.
 *
 * \asf_license_start
 *
 * \page License
 *
 * 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. The name of Atmel may not be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 4. This software may only be redistributed and used in connection with an
 *    Atmel microcontroller product.
 *
 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 *
 * \asf_license_stop
 *
 */
#include <asf.h>
#include <conf_timeout.h>

/* Check if RTC32 is defined, otherwise use RTC as default */
#if defined(CLOCK_SOURCE_RTC32)
  #include <rtc32.h>
#else
  #include <rtc.h>
#endif

/** \brief Timeout timekeeping data */
struct timeout_struct {
	/**
	 * Current count-down value. Counts down for every tick.
	 * Will be considered as expired when it reaches 0, and
	 * may then be reloaded with period.
	 */
	uint16_t count;

	/**
	 * Period between expires. Used to reload count.
	 * If 0, the count won't be reloaded.
	 */
	uint16_t period;
};

/** Array of configurable timeout timekeeping data */
static struct timeout_struct timeout_array[TIMEOUT_COUNT];

/** Bitmask of active timeouts */
static uint8_t timeout_active;

/** Bitmask of expired timeouts */
static uint8_t timeout_expired;

/**
 * \brief Callback function for RTC compare interrupt handler
 *
 * The function executes when the RTC compare interrupt occurs and loop
 * through all timeout channels. The timeout_array[channel_index] which
 * contains the remaining ticks before timeout is decremented and the timeout
 * active/expired masks are updated.
 */
static void tick_handler(uint32_t time)
{
	uint8_t i;

	/* Loop through all timeout channels */
	for (i = 0; i < TIMEOUT_COUNT; i++) {
		/* Skip processing on current channel if not active */
		if (!(timeout_active & (1 << i))) {
			continue;
		}

		/* Decrement current channel with one tick */
		timeout_array[i].count--;

		/* Skip further processing on current channel if not expired */
		if (timeout_array[i].count) {
			continue;
		} else {
			/* Update expired bit mask with current channel */
			timeout_expired |= 1 << i;

			/* If Periodic timer, reset timeout counter to period
			 * time */
			if (timeout_array[i].period) {
				timeout_array[i].count
					= timeout_array[i].period;
			}
			/* If not periodic timeout, set current channel to
			 * in-active */
			else {
				timeout_active &= ~(1 << i);
			}
		}
	}
	/* Reset RTC before next tick */
	rtc_set_time(0);
	rtc_set_alarm(TIMEOUT_COMP);
}

/**
 * \brief Initialize timeout
 *
 * Initializes timeout counter for desired tick rate and starts it. The device
 * interrupt controller should be initialized prior to calling this function,
 * and global interrupts must be enabled.
 *
 * \note If the service is configured to use the asynchronous RTC32 module,
 *       there are restrictions on the timeout period that can be used - see
 *       to \ref rtc32_min_alarm_time for details.
 */
void timeout_init(void)
{
	rtc_init();
	rtc_set_callback(tick_handler);
	rtc_set_time(0);
	rtc_set_alarm(TIMEOUT_COMP);
}

/**
 * \brief Start periodic timeout with a specific start timeout
 *
 * \param id            \ref timeout_id_t
 * \param period        Time period in number of ticks
 * \param offset        Time to first timeout in number of ticks
 */
void timeout_start_offset(timeout_id_t id, uint16_t period, uint16_t offset)
{
	/* Check that ID within the TIMEOUT_COUNT range */
	if (id < TIMEOUT_COUNT) {
		/* Disable interrupts before tweaking the bitmasks */
		irqflags_t flags;
		flags = cpu_irq_save();

		/* Update timeout struct with offset and period */
		timeout_array[id].count = offset;
		timeout_array[id].period = period;

		/* Set current timeout channel bitmasks to active and not
		 * expired */
		timeout_active |= 1 << id;
		timeout_expired &= ~(1 << id);

		/* Restore interrupts */
		cpu_irq_restore(flags);
	}
}

/**
 * \brief Start singleshot timeout
 *
 * \param id       \ref timeout_id_t
 * \param timeout  Timeout in number of ticks
 */
void timeout_start_singleshot(timeout_id_t id, uint16_t timeout)
{
	timeout_start_offset(id, 0, timeout);
}

/**
 * \brief Start periodic timeout
 *
 * \param id      \ref timeout_id_t
 * \param period  Time period in number of ticks
 */
void timeout_start_periodic(timeout_id_t id, uint16_t period)
{
	timeout_start_offset(id, period, period);
}

/**
 * \brief Test and clear expired flag for running timeout
 *
 * \param id      \ref timeout_id_t
 * \retval true   Timer have expired; clearing expired flag
 * \retval false  Timer still running
 */
bool timeout_test_and_clear_expired(timeout_id_t id)
{
	/* Check that ID within the TIMEOUT_COUNT range */
	if (id < TIMEOUT_COUNT) {
		irqflags_t flags;

		/* Check if timeout has expired */
		if (timeout_expired & (1 << id)) {
			flags = cpu_irq_save();
			timeout_expired &= ~(1 << id);
			cpu_irq_restore(flags);
			return true;
		}
	}

	return false;
}

/**
 * \brief Stop running timeout
 *
 * \param id \ref timeout_id_t
 */
void timeout_stop(timeout_id_t id)
{
	irqflags_t flags;
	flags = cpu_irq_save();
	timeout_active &= ~(1 << id);
	cpu_irq_restore(flags);
}