mbed-os/connectivity/nfc/source/NFCController.cpp

/* mbed Microcontroller Library
 * Copyright (c) 2018 ARM Limited
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "NFCController.h"
#include "NFCControllerDriver.h"
#include "Type4RemoteInitiator.h"

#include "stack/transceiver/transceiver.h"

using std::milli;
using namespace std::chrono;
using namespace mbed;
using namespace mbed::nfc;

NFCController::NFCController(NFCControllerDriver *driver, events::EventQueue *queue, const Span<uint8_t> &ndef_buffer) :
    _driver(driver), _queue(queue), _transceiver(NULL), _scheduler(NULL), _delegate(NULL), _discovery_running(false), _ndef_buffer(ndef_buffer)
{
    _driver->set_delegate(this);
}

nfc_err_t NFCController::initialize()
{
    MBED_ASSERT(_transceiver == NULL); // Initialize should only be called once
    _transceiver = _driver->initialize((nfc_scheduler_timer_t *)&_timer); // See implementation below

    if (_transceiver == NULL) {
        // Initialization error
        return NFC_ERR_CONTROLLER; // Controller error
    }

    // Recover scheduler
    _scheduler = transceiver_get_scheduler(_transceiver);

    // Run scheduler for the first time
    _queue->call(this, &NFCController::scheduler_process, false);

    return NFC_OK;
}

void NFCController::set_delegate(Delegate *delegate)
{
    _delegate = delegate;
}

nfc_rf_protocols_bitmask_t NFCController::get_supported_rf_protocols() const
{
    // nfc_rf_protocols_bitmask_t is mapped on NFC Forum types, nfc_tech_t is mapped on the underlying RF techs
    // We therefore need to convert these

    nfc_rf_protocols_bitmask_t rf_protocols = {0};
    nfc_tech_t initiator_tech;
    nfc_tech_t target_tech;
    _driver->get_supported_nfc_techs(&initiator_tech, &target_tech);

    // Note: we only support ISO-DEP tag emulation in this release,
    // so mask out all other protocols

    // rf_protocols.initiator_t1t = initiator_tech.nfc_type1;
    // rf_protocols.initiator_t2t = initiator_tech.nfc_type2;
    // rf_protocols.initiator_t3t = initiator_tech.nfc_type3;
    // rf_protocols.initiator_iso_dep = initiator_tech.nfc_iso_dep_a || initiator_tech.nfc_iso_dep_b;
    // rf_protocols.initiator_nfc_dep = initiator_tech.nfc_nfc_dep_a || initiator_tech.nfc_nfc_dep_f_212 || initiator_tech.nfc_nfc_dep_f_424;

    // rf_protocols.target_t1t = target_tech.nfc_type1;
    // rf_protocols.target_t2t = target_tech.nfc_type2;
    // rf_protocols.target_t3t = target_tech.nfc_type3;
    rf_protocols.target_iso_dep = target_tech.nfc_iso_dep_a || target_tech.nfc_iso_dep_b;
    // rf_protocols.target_nfc_dep = target_tech.nfc_nfc_dep_a || target_tech.nfc_nfc_dep_f_212 || target_tech.nfc_nfc_dep_f_424;

    return rf_protocols;
}

nfc_err_t NFCController::configure_rf_protocols(nfc_rf_protocols_bitmask_t rf_protocols)
{
    if (_discovery_running) {
        // Cannot configure RF protocols if discovery is running
        return NFC_ERR_BUSY;
    }

    // Map to NFC techs
    nfc_tech_t initiator_tech = {0};
    nfc_tech_t target_tech = {0};

    // Note: we only support ISO-DEP tag emulation in this release,
    // so mask out all other protocols

    target_tech.nfc_iso_dep_a = target_tech.nfc_iso_dep_b =  true;

    // Configure polling options (no need to set bailing flags as we're only using target mode)
    polling_options_t options = {0};
    options.listen_for = -1; // Listen forever

    transceiver_set_protocols(_transceiver, initiator_tech, target_tech, options);

    return NFC_OK;
}

nfc_err_t NFCController::start_discovery()
{
    if (_discovery_running) {
        // Cannot start discovery if it's already running
        return NFC_ERR_BUSY;
    }

    transceiver_poll(_transceiver, &NFCController::s_polling_callback, this /* use this as callback argument */);

    return NFC_OK;
}

nfc_err_t NFCController::cancel_discovery()
{
    if (!_discovery_running) {
        return NFC_OK;
    }

    transceiver_abort(_transceiver);

    return NFC_OK;
}

nfc_transceiver_t *NFCController::transceiver() const
{
    return _transceiver;
}

void NFCController::polling_callback(nfc_err_t ret)
{
    // Polling has completed
    _discovery_running = false;

    NFC_DBG("Polling finished with result %u", ret);

    if (ret == NFC_OK) {
        // Check if a remote initiator was detected and if so, instantiate it
        if (!transceiver_is_initiator_mode(_transceiver)) {
            nfc_tech_t active_tech = transceiver_get_active_techs(_transceiver);
            if ((active_tech.nfc_iso_dep_a || active_tech.nfc_iso_dep_b) && (_delegate != NULL)) {
                Type4RemoteInitiator *type4_remote_initiator_ptr = new (std::nothrow) Type4RemoteInitiator(this, _ndef_buffer);
                if (type4_remote_initiator_ptr != NULL) {
                    SharedPtr<NFCRemoteInitiator> type4_remote_initiator(type4_remote_initiator_ptr);
                    _delegate->on_nfc_initiator_discovered(type4_remote_initiator);
                }
            }
        }
    }

    if (_delegate != NULL) {
        Delegate::nfc_discovery_terminated_reason_t reason;

        // Map reason
        switch (ret) {
            case NFC_OK:
                reason = Delegate::nfc_discovery_terminated_completed;
                break;
            case NFC_ERR_ABORTED:
                reason = Delegate::nfc_discovery_terminated_canceled;
                break;
            default:
                // Any other error code means there was an error during the discovery process
                reason = Delegate::nfc_discovery_terminated_rf_error;
                break;
        }

        _delegate->on_discovery_terminated(reason);
    }
}

void NFCController::scheduler_process(bool hw_interrupt)
{
    _timeout.detach(); // Cancel timeout - if it triggers, it's ok as we'll have an "early" iteration which will likely be a no-op

    // Process stack events
    duration<uint32_t, milli> timeout{nfc_scheduler_iteration(_scheduler, hw_interrupt ? EVENT_HW_INTERRUPT : EVENT_NONE)};

    _timeout.attach(callback(this, &NFCController::on_timeout), timeout);
}

void NFCController::on_hw_interrupt()
{
    // Run scheduler - this is called in interrupt context
    _timeout.detach(); // Cancel timeout - if it triggers anyways, it's ok
    _queue->call(this, &NFCController::scheduler_process, true);
}

void NFCController::on_timeout()
{
    // Run scheduler - this is called in interrupt context
    _queue->call(this, &NFCController::scheduler_process, false);
}

void NFCController::s_polling_callback(nfc_transceiver_t *pTransceiver, nfc_err_t ret, void *pUserData)
{
    NFCController *self = (NFCController *) pUserData;
    self->polling_callback(ret);
}

// Implementation nfc_scheduler_timer_t
void nfc_scheduler_timer_init(nfc_scheduler_timer_t *timer)
{
    (void)timer; // This is a no-op
}

void nfc_scheduler_timer_start(nfc_scheduler_timer_t *timer)
{
    Timer *mbed_timer = (Timer *)timer;
    mbed_timer->start();
}

uint32_t nfc_scheduler_timer_get(nfc_scheduler_timer_t *timer)
{
    Timer *mbed_timer = (Timer *)timer;
    return (uint32_t)std::chrono::duration_cast<std::chrono::milliseconds>(
               mbed_timer->elapsed_time()
           ).count();
}

void nfc_scheduler_timer_stop(nfc_scheduler_timer_t *timer)
{
    Timer *mbed_timer = (Timer *)timer;
    mbed_timer->stop();
}

void nfc_scheduler_timer_reset(nfc_scheduler_timer_t *timer)
{
    Timer *mbed_timer = (Timer *)timer;
    mbed_timer->reset();
}