/**
 * @file
 * @brief This file implements the MLME-SYNC.request.
 *
 * $Id: sync.c,v 1.24 2006/12/22 07:27:25 sschneid Exp $
 */
/**
 *  \author
 *      Atmel Corporation: http://www.atmel.com
 *      Support email: avr@atmel.com
 */
/*
 * Copyright (c) 2006, Atmel Corporation 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 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.
 *
 * THIS SOFTWARE IS PROVIDED BY ATMEL ``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 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.
 */

/* === Includes ============================================================ */

#include "mac.h"
#include "timer_const.h"

#if APP_TYPE >= APP_L2 || defined(DOXYGEN)

/* === Globals ============================================================= */


/* === Prototypes ========================================================== */


/* === Implementation ====================================================== */

/**
 * @brief   This function implements the MLME-SYNC request.
 *
 * The MLME-SYNC.request primitive requests to synchronize with the coordinator by
 * acquiring and, if specified, tracking its beacons.
 * The MLME-SYNC.request primitive is generated by the next higher layer of a device
 * on a beacon-enabled PAN and issued to its MLME to synchronize with the coordinator.
 *
 * Enable receiver and search for beacons for at most an interval of
 * [aBaseSuperframeDuration * (2^(n) +1)] symbols where n is the value of
 * macBeaconOrder. If a beacon frame containing
 * the current PAN identifier of the device is not received, the MLME shall
 * repeat this search. Once the number of missed beacons reaches
 * aMaxLostBeacons, the MLME shall notify the next higher layer by issuing the
 * MLME-SYNC-LOSS.indication primitive with a loss reason of BEACON_LOSS.
 *
 * @param m Pointer to the sync request parameters
 */
void mlme_sync_request(uint8_t *m)
{
    plme_set_trx_state_req_t txr;

    mlme_sync_req_t *syr = (mlme_sync_req_t *)m;

    uint8_t        psr_buffer[sizeof(plme_set_req_t) + sizeof(uint8_t)];
    plme_set_req_t *psr = (plme_set_req_t *)psr_buffer;

    if (mac_i_pan_coordinator)
    {
        return;
    }

    // We need to be in a non-transient state to be able to properly process a sync request
    if (!((mac_state == MAC_A) || (mac_state == MAC_Tracking_Beacon)))
    {
        mac_sync_loss(MAC_BEACON_LOSS);
        return;
    }

    // Stop potential timers for beacon tracking
    bios_stoptimer(T_bt_missedbeacon);
    bios_stoptimer(T_btp);

    // Set the channel, we'll pick up the sync in an intermediate function.
    psr->size = sizeof(plme_set_req_t) - sizeof(psr->size) + sizeof(uint8_t);
    psr->cmdcode = PLME_SET_REQUEST;
    psr->PIBAttribute = phyCurrentChannel;
    psr->data[0]      = sizeof(uint8_t);
    psr->data[1]      = syr->LogicalChannel;
    bios_pushback_event((uint8_t *) psr);

    // Turn the radio on.
    txr.size = sizeof(plme_set_trx_state_req_t) - sizeof(txr.size);
    txr.cmdcode = PLME_SET_TRX_STATE_REQUEST;
    txr.state = PHY_RX_ON;
    bios_pushback_event((uint8_t *) &txr);

    // Set mac_state to MAC_Tracking_Beacon. This will cause the FSM to pick
    // up beacon processing in data_ind.c when a beacon is received.
    // Record a global track beacon by setting the mac_state and mac_trackBeacons.
    if(syr->TrackBeacon)
    {
        mac_trackBeacons = SYNC_CONTINUOUSLY;
        mac_state = MAC_Tracking_Beacon;
    }
    else
    {
        mac_trackBeacons = SYNC_ONCE;
        // we need to restore mac state from continuous beacon tracking to associated state
        // or we will keep tracking forever
        mac_state = MAC_A;
    }

    mac_missed_beacons = 0;

    if (!bios_starttimer(T_bt_missedbeacon,
                         MAC_CALCULATE_SYMBOL_TIME_BEACONINTERVAL(mac_pib_macBeaconOrder)))
    {
        // Scan timer that checks whether we are actually receiving beacon frames could not be started
        // Indicate sync loss indication
        mac_sync_loss(MAC_BEACON_LOSS);
        mac_trackBeacons = SYNC_NEVER;
        mac_state = MAC_A;
    }
}



/**
 * @brief Timer function after sync request to wake up radio at beacon time
 *
 * This function implements the RX timer service function during sync and enables the receiver before
 * the next beacon reception is expected.
 */
void mac_t_tracking_beacons(void)
{
    plme_set_trx_state_req_t txr;

    if(mac_trackBeacons != SYNC_NEVER)
    {
        bios_stoptimer(T_btp);
    }

    // Turn the radio on.
    txr.size = sizeof(plme_set_trx_state_req_t) - sizeof(txr.size);
    txr.cmdcode = PLME_SET_TRX_STATE_REQUEST;
    txr.state = PHY_RX_ON;
    bios_pushback_event((uint8_t *) &txr);
}



/**
 * @brief Timer function after sync request to count missed beacon frames
 *
 * This function implements the counting of missed beacon frames during sync.
 */
void mac_t_missed_beacons(void)
{
    if (mac_state == MAC_W)
    {
        // have been disassociated meanwhile and are in idle state
        mac_sync_loss(MAC_BEACON_LOSS);
        mac_trackBeacons = SYNC_NEVER;
    }

    if(mac_trackBeacons != SYNC_NEVER)
    {
        mac_missed_beacons++;
        if (mac_missed_beacons >= aMaxLostBeacons)
        {
            mac_sync_loss(MAC_BEACON_LOSS);
            mac_trackBeacons = SYNC_NEVER;
            mac_state = MAC_A;
        }
        else
        {
            uint32_t duration = MAC_CALCULATE_SYMBOL_TIME_BEACONINTERVAL(mac_pib_macBeaconOrder);
            /* Wait a bit longer, duration = beacon interval * 1.25 */
            if (!bios_starttimer(T_bt_missedbeacon, duration + (duration >> 2)))
            {
                // Scan timer that checks whether we are actually receiving beacon frames could not be started
                // Indicate sync loss indication
                mac_sync_loss(MAC_BEACON_LOSS);
                mac_trackBeacons = SYNC_NEVER;
                mac_state = MAC_A;
            }
        }
    }
}



/**
 * @brief Function to initiate a MLME-SYNC-LOSS.indication to the higher layer
 *
 * @param uint8_t loss_reason LossReason to be indicated within the primitive
 */
void mac_sync_loss(uint8_t loss_reason)
{
        mlme_sync_loss_ind_t msli;
        msli.size       = sizeof(mlme_sync_loss_ind_t) - sizeof(msli.size);
        msli.cmdcode    = MLME_SYNC_LOSS_INDICATION;
        msli.LossReason = loss_reason;
        bios_pushback_event(&msli);
}

#endif // APP_TYPE >= APP_L2 || defined(DOXYGEN)


/* EOF */