/**
 * @file
 * @brief Implement the MLME-RX-ENABLE messages.
 *
 * $Id: rx_enable.c,v 1.15 2007/05/15 09:02:48 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 "phy.h"
#include "timer_const.h"

#if APP_TYPE >= APP_L2 || defined(DOXYGEN)
/* === Globals ============================================================= */

/*
 * This variable temporarily remembers the duration for which the receiver
 * is to be enabled
 */
static uint32_t RxOnDurationTime;

/*
 * This variable temporarily remembers the time when the receiver is
 * due to be turned off.
 */
static uint32_t RxOffTime;

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

/* === Implementation ====================================================== */
/**
 * @brief   Implement the MLME-RX-ENABLE.request primitive.
 *
 * The MLME-RX-ENABLE.request primitive is generated by the next
 * higher layer and issued to the MLME to enable the receiver for a
 * fixed duration, at a time relative to the start of the current or
 * next superframe on a beacon-enabled PAN or immediately on a
 * nonbeacon-enabled PAN. The receiver is enabled exactly once per
 * primitive request.
 *
 * @param m Pointer to the MLME-RX-ENABLE.request message
 */
void mlme_rx_enable_request(uint8_t *m)
{
    uint32_t symbols_since_beacon;
    uint32_t symbols_remaining_in_cap;
    uint32_t start_time;
    uint16_t offTime;
    mlme_rx_enable_req_t *rxe = (mlme_rx_enable_req_t *)m;
    mlme_rx_enable_conf_t rec;

    // Reject the request when the MAC is currently in any of the
    // transient states (scan, CSMA-CA).
    switch (mac_state)
    {
    case MAC_W:
    case MAC_Ya:
    case MAC_Za:
    case MAC_Zp:
    case MAC_A:
    case MAC_Tracking_Beacon:
        /* OK to enable receiver here. */
        break;

    default:
        // Send the confirm immediately.
        rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
        rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
        rec.status = MAC_TX_ACTIVE;
        bios_pushback_event(&rec);
        return;
    }

    // Remember the duration for which the receiver is to be enabled
    RxOnDurationTime = rxe->RxOnDuration;

    // Handle rxe->RxOnDuration == 0 and non-beacon enabled PANs because
    // the PHY has to be awake in both cases.
    if ( (rxe->RxOnDuration == 0) ||
        (mac_pib_macBeaconOrder == NON_BEACON_NETWORK) )
    {
        // remember the original MAC state
        mac_original_state = mac_state;

        // do we need to wake up the radio first?
        if (mac_radio_sleep_state == RADIO_SLEEPING)
        {
            mac_state = MAC_WAKEUP_RX_ENABLE;

            // wake up radio first
            mac_phy_wakeup();
        }
        else
        {
            mac_awake_rx_enable();
        }

        return;
    }

    // Handle beacon enabled PANs

    /*
     * Deterimine if (RxOnTime + RxOnDuration) is less than the beacon
     * interval. mac_RollOverTimeThis holds the BI in symbol time. According
     * to 7.1.10.1.3:
     *
     * On a beacon-enabled PAN, the MLME first determines whether
     * (RxOnTime + RxOnDuration) is less than the beacon interval, defined
     * by macBeaconOrder. If it is not less, the MLME issues the
     * MLME-RX-ENABLE.confirm primitive with a status of INVALID_PARAMETER.
     */

    offTime = rxe->RxOnTime + rxe->RxOnDuration;
    if (offTime >= mac_RollOverTime)
    {
        // Send the confirm immediately.
        rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
        rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
        rec.status = MAC_INVALID_PARAMETER;
        bios_pushback_event(&rec);

        return;
    }

    // mac_pib_macBeaconTxTime contains the system (symbol) time when
    // the last beacon was sent or received.
    symbols_since_beacon  = bios_sub_time(bios_gettime(), mac_pib_macBeaconTxTime);

    // Actually, MLME-RX-ENABLE.requests in a beacon enabled PAN do
    // only make sense if this MAC is currently tracking beacons, so
    // that mac_pib_macBeaconTxTime is up to date.  If it appears that
    // the last known mac_pib_macBeaconTxTime does not relate to the
    // current superframe, reject the request.
    if (symbols_since_beacon > mac_RollOverTime)
    {
        // Send the confirm immediately.
        rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
        rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
        rec.status = MAC_INVALID_PARAMETER;
        bios_pushback_event(&rec);

        return;
    }

    // Determine the number of symbols remaining in the CAP.
    symbols_remaining_in_cap = (mac_SOInactiveTime / aNumSuperframeSlots) * (mac_FinalCapSlot + 1);
    symbols_remaining_in_cap -= symbols_since_beacon;

    if (symbols_remaining_in_cap < offTime)
    {
        // If it doesn't fit into the CAP, see whether deferred
        // handling is allowed or not.
        if (rxe->DeferPermit)
        {
            start_time = bios_add_time(mac_pib_macBeaconTxTime,
                                       mac_RollOverTime + rxe->RxOnTime);
        }
        else
        {
            rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
            rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
            rec.status = MAC_OUT_OF_CAP;
            bios_pushback_event(&rec);

            return;
        }
    }
    else
    {
        // Request fits into the CAP.
        start_time = bios_add_time(mac_pib_macBeaconTxTime, rxe->RxOnTime);
    }

    // Start a timer to turn on RX at the appointed time
    // "rxe->RxOnTime" from the start of the next superframe.
    bios_start_absolute_timer(T_RxOnTime, start_time);

    // Remember the time we are supposed to turn off the receiver.
    RxOffTime = bios_add_time(start_time, rxe->RxOnDuration);

    // We were successful so far.  The MLME-RX-ENABLE.confirm message
    // will be generated once the T_RxOnTime timer expired, and the
    // receiver has actually been enabled.
}


/**
 * @brief Continues handling of MLME-RX-ENABLE.request once the radio is awake
 */
void mac_awake_rx_enable(void)
{
    plme_set_trx_state_req_t txr;
    plme_set_trx_state_conf_t tsc;
    mlme_rx_enable_conf_t rec;

    // If RxOnDurationTime is 0 we are supposed to disable the
    // receiver.
    if (RxOnDurationTime == 0)
    {
        // Turn the radio off.
        txr.size = sizeof(plme_set_trx_state_req_t) - sizeof(txr.size);
        txr.cmdcode = PLME_SET_TRX_STATE_REQUEST;
        txr.state = PHY_TRX_OFF;
        plme_set_trx_state_request_internal(&txr, &tsc);

        // Send the confirm immediately.
        rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
        rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
        if ((tsc.status == PHY_SUCCESS) || (tsc.status == PHY_TRX_OFF))
        {
            rec.status = MAC_SUCCESS;
        }
        else
        {
            rec.status = MAC_TX_ACTIVE;
        }

        // set the MAC state to it's original state
        mac_state = mac_original_state;

        // go to sleep?
        if(!mac_pib_macRxOnWhenIdle)
        {
            // set sleep=true
            mac_phy_init_sleep();
        }

        bios_pushback_event(&rec);

        return;
    }

    // Handle non-beacon enabled and beacon enabled PANs firstly together

    // Turn the receiver on immediately.
    txr.size = sizeof(plme_set_trx_state_req_t) - sizeof(txr.size);
    txr.cmdcode = PLME_SET_TRX_STATE_REQUEST;
    txr.state = PHY_RX_ON;
    plme_set_trx_state_request_internal(&txr, &tsc);

    // Send the confirm immediately.
    rec.size = sizeof(mlme_rx_enable_conf_t) - sizeof(rec.size);
    rec.cmdcode = MLME_RX_ENABLE_CONFIRM;
    if ((tsc.status == PHY_SUCCESS) || (tsc.status == PHY_RX_ON))
    {
        rec.status = MAC_SUCCESS;
        // Set a timer event upon exipry the receiver will be turned off.
        // RxOnDuration is contained in the incomming message.
        // Distinction of non-beacon enabled and beacon enabled PANs at this point.
        if (mac_pib_macBeaconOrder == NON_BEACON_NETWORK)
        {
            // Handle non-beacon enabled PANs
            bios_starttimer(T_RxOffTime, RxOnDurationTime);
        }
        else
        {
            // Handle beacon enabled PANs
            bios_start_absolute_timer(T_RxOffTime, RxOffTime);
        }
    }
    else
    {
        rec.status = MAC_TX_ACTIVE;
    }

    // set the MAC state to it's original state
    mac_state = mac_original_state;

    bios_pushback_event(&rec);

    return;
}

/**
 * @brief The RX "on" timer.
 *
 * This actually turns the radio receiver on - i.e. this is the
 * beginning of the RX_ON period.
 */
void mac_t_rx_enable_duration_start(void)
{
    // remember the original MAC state
    mac_original_state = mac_state;

    // do we need to wake up the radio first?
    if (mac_radio_sleep_state == RADIO_SLEEPING)
    {
        mac_state = MAC_WAKEUP_RX_ENABLE;

        // wake up radio first
        mac_phy_wakeup();
    }
    else
    {
        mac_awake_rx_enable();
    }
}


/**
 * @brief   The RX "off" timer.
 *
 * This actually turns the radio receiver off - i.e. this is the end
 * of the RX_ON period.
 */
void mac_t_rx_enable_duration_expired(void)
{
    plme_set_trx_state_req_t txr;
    plme_set_trx_state_conf_t tsc;

    // Turn off the radio now.
    txr.size = sizeof(plme_set_trx_state_req_t) - sizeof(txr.size);
    txr.cmdcode = PLME_SET_TRX_STATE_REQUEST;
    txr.state = PHY_TRX_OFF;
    plme_set_trx_state_request_internal(&txr, &tsc);

    // Nobody is going to be interested in the success of that.

    // go to sleep?
    if(!mac_pib_macRxOnWhenIdle)
    {
        // set sleep=true
        mac_phy_init_sleep();
    }
}

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