app_timer_freertos.c

/**
 * Copyright (c) 2014 - 2017, Nordic Semiconductor ASA
 * 
 * All rights reserved.
 * 
 * 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, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, 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 name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 * 
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA 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.
 * 
 */
#include "sdk_common.h"
#if NRF_MODULE_ENABLED(APP_TIMER)
#include "FreeRTOS.h"
#include "task.h"
#include "timers.h"

#include "app_timer.h"
#include <stdlib.h>
#include <string.h>
#include "nrf.h"
#include "app_error.h"

/**
 * Note that this implementation is made only for enable SDK components which interacts with app_timer to work with FreeRTOS.
 * It is more suitable to use native FreeRTOS timer for other purposes.
 */
/* Check if RTC FreeRTOS version is used */
#if configTICK_SOURCE != FREERTOS_USE_RTC
#error app_timer in FreeRTOS variant have to be used with RTC tick source configuration. Default configuration have to be used in other case.
#endif

/**
 * @brief Waiting time for the timer queue
 *
 * Number of system ticks to wait for the timer queue to put the message.
 * It is strongly recommended to set this to the value bigger than 1.
 * In other case if timer message queue is full - any operation on timer may fail.
 * @note
 * Timer functions called from interrupt context would never wait.
 */
#define APP_TIMER_WAIT_FOR_QUEUE 2

/**@brief This structure keeps information about osTimer.*/
typedef struct
{
    void                      * argument;
    TimerHandle_t               osHandle;
    app_timer_timeout_handler_t func;
    /**
     * This member is to make sure that timer function is only called if timer is running.
     * FreeRTOS may have timer running even after stop function is called,
     * because it processes commands in Timer task and stopping function only puts command into the queue. */
    bool                        active;
}app_timer_info_t;


/* Check if freeRTOS timers are activated */
#if configUSE_TIMERS == 0
    #error app_timer for freeRTOS requires configUSE_TIMERS option to be activated.
#endif

/* Check if app_timer_t variable type can held our app_timer_info_t structure */
STATIC_ASSERT(sizeof(app_timer_info_t) <= sizeof(app_timer_t));


/**
 * @brief Internal callback function for the system timer
 *
 * Internal function that is called from the system timer.
 * It gets our parameter from timer data and sends it to user function.
 * @param[in] xTimer Timer handler
 */
static void app_timer_callback(TimerHandle_t xTimer)
{
    app_timer_info_t * pinfo = (app_timer_info_t*)(pvTimerGetTimerID(xTimer));
    ASSERT(pinfo->osHandle == xTimer);
    ASSERT(pinfo->func != NULL);

    if (pinfo->active)
        pinfo->func(pinfo->argument);
}


uint32_t app_timer_init(void)
{
    return NRF_SUCCESS;
}


uint32_t app_timer_create(app_timer_id_t const *      p_timer_id,
                          app_timer_mode_t            mode,
                          app_timer_timeout_handler_t timeout_handler)
{
    app_timer_info_t * pinfo = (app_timer_info_t*)(*p_timer_id);
    uint32_t      err_code = NRF_SUCCESS;
    unsigned long timer_mode;

    if ((timeout_handler == NULL) || (p_timer_id == NULL))
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    if (pinfo->active)
    {
        return NRF_ERROR_INVALID_STATE;
    }

    if (pinfo->osHandle == NULL)
    {
        /* New timer is created */
        memset(pinfo, 0, sizeof(app_timer_info_t));

        if (mode == APP_TIMER_MODE_SINGLE_SHOT)
            timer_mode = pdFALSE;
        else
            timer_mode = pdTRUE;

        pinfo->func = timeout_handler;
        pinfo->osHandle = xTimerCreate(" ", 1000, timer_mode, pinfo, app_timer_callback);

        if (pinfo->osHandle == NULL)
            err_code = NRF_ERROR_NULL;
    }
    else
    {
        /* Timer cannot be reinitialized using FreeRTOS API */
        return NRF_ERROR_INVALID_STATE;
    }

    return err_code;
}


uint32_t app_timer_start(app_timer_id_t timer_id, uint32_t timeout_ticks, void * p_context)
{
    app_timer_info_t * pinfo = (app_timer_info_t*)(timer_id);
    TimerHandle_t hTimer = pinfo->osHandle;

    if (hTimer == NULL)
    {
        return NRF_ERROR_INVALID_STATE;
    }
    if (pinfo->active && (xTimerIsTimerActive(hTimer) != pdFALSE))
    {
        // Timer already running - exit silently
        return NRF_SUCCESS;
    }

    pinfo->argument = p_context;

    if (__get_IPSR() != 0)
    {
        BaseType_t yieldReq = pdFALSE;
        if (xTimerChangePeriodFromISR(hTimer, timeout_ticks, &yieldReq) != pdPASS)
        {
            return NRF_ERROR_NO_MEM;
        }

        if ( xTimerStartFromISR(hTimer, &yieldReq) != pdPASS )
        {
            return NRF_ERROR_NO_MEM;
        }

        portYIELD_FROM_ISR(yieldReq);
    }
    else
    {
        if (xTimerChangePeriod(hTimer, timeout_ticks, APP_TIMER_WAIT_FOR_QUEUE) != pdPASS)
        {
            return NRF_ERROR_NO_MEM;
        }

        if (xTimerStart(hTimer, APP_TIMER_WAIT_FOR_QUEUE) != pdPASS)
        {
            return NRF_ERROR_NO_MEM;
        }
    }

    pinfo->active = true;
    return NRF_SUCCESS;
}


uint32_t app_timer_stop(app_timer_id_t timer_id)
{
    app_timer_info_t * pinfo = (app_timer_info_t*)(timer_id);
    TimerHandle_t hTimer = pinfo->osHandle;
    if (hTimer == NULL)
    {
        return NRF_ERROR_INVALID_STATE;
    }

    if (__get_IPSR() != 0)
    {
        BaseType_t yieldReq = pdFALSE;
        if (xTimerStopFromISR(hTimer, &yieldReq) != pdPASS)
        {
            return NRF_ERROR_NO_MEM;
        }
        portYIELD_FROM_ISR(yieldReq);
    }
    else
    {
        if (xTimerStop(hTimer, APP_TIMER_WAIT_FOR_QUEUE) != pdPASS)
        {
            return NRF_ERROR_NO_MEM;
        }
    }

    pinfo->active = false;
    return NRF_SUCCESS;
}
#endif //NRF_MODULE_ENABLED(APP_TIMER)