mbed-os/features/nfc/nfc/NFCEEPROM.h

/* mbed Microcontroller Library
 * Copyright (c) 2018 ARM Limited
 *
 * 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.
 */

#ifndef MBED_NFC_EEPROM_H
#define MBED_NFC_EEPROM_H

#include <stdint.h>
#include "events/EventQueue.h"

#include "NFCDefinitions.h"
#include "NFCTarget.h"
#include "NFCEEPROMDriver.h"

namespace mbed {
namespace nfc {

/**
 * @addtogroup nfc
 * @{
 */

/**
 * The NFC EEPROM class represents a NFC target device connected using a wired
 * link (I2C, SPI, etc).
 *
 * These EEPROMs essentially provide addressable memory that can be accessed
 * using either a wired or NFC interface.
 *
 * In NFC mode these most often conform to one of the NFC tag types defined
 * by the NFC Forum, therefore encoding NDEF data in these EEPROMs will
 * ensure that it is understandable by a NFC reader.
 */
class NFCEEPROM : public NFCTarget, public NFCEEPROMDriver::Delegate {
public:
    /**
     * Construct a NFCEEPROM instance.
     *
     * @param[in] driver a pointer to a NFCEEPROMDriver instance
     * @param[in] queue a pointer to the events queue to use
     * @param[in] ndef_buffer a bytes array used to store NDEF messages
     */
    NFCEEPROM(NFCEEPROMDriver *driver, events::EventQueue *queue, const Span<uint8_t> &ndef_buffer);

    /**
     * The NFCEEPROM delegate. Users of the NFCEEPROM class need to implement this delegate's methods to receive events.
     */
    struct Delegate : NFCTarget::Delegate {
        /**
         * The NDEF message erasing request completed.
         *
         * @param[in] result NFC_OK or an error code on failure
         */
        virtual void on_ndef_message_erased(nfc_err_t result) {}

        /**
         * The NDEF message writing request completed.
         *
         * @param[in] result NFC_OK or an error code on failure
         */
        virtual void on_ndef_message_written(nfc_err_t result) {}

        /**
         * The NDEF message reading request completed.
         *
         * @param[in] result NFC_OK or an error code on failure
         */
        virtual void on_ndef_message_read(nfc_err_t result) {}

    protected:
        ~Delegate() {}
    };

    /**
     * Initialize the NFC EEPROM
     *
     * This method must be called before any other method call.
     *
     * @return NFC_OK, or an error.
     */
    nfc_err_t initialize();

    /**
     * Set the delegate that will receive events generated by this EEPROM.
     *
     * @param[in] delegate the delegate instance to use
     */
    void set_delegate(Delegate *delegate);

    // Implementation of NFCTarget
    virtual void write_ndef_message();
    virtual void read_ndef_message();
    virtual void erase_ndef_message();

private:
    // Implementation of NFCEEPROMDriver::Delegate
    virtual void on_session_started(bool success);
    virtual void on_session_ended(bool success);
    virtual void on_bytes_read(size_t count);
    virtual void on_bytes_written(size_t count);
    virtual void on_size_written(bool success);
    virtual void on_size_read(bool success, size_t size);
    virtual void on_bytes_erased(size_t count);

    void handle_error(nfc_err_t ret);
    void continue_write();
    void continue_read();
    void continue_erase();

    // NFCNDEFCapable implementation
    virtual NFCNDEFCapable::Delegate *ndef_capable_delegate();

    enum nfc_eeprom_operation_t {
        nfc_eeprom_idle,

        nfc_eeprom_write_start_session,
        nfc_eeprom_write_write_size,
        nfc_eeprom_write_write_bytes,
        nfc_eeprom_write_end_session,

        nfc_eeprom_read_start_session,
        nfc_eeprom_read_read_size,
        nfc_eeprom_read_read_bytes,
        nfc_eeprom_read_end_session,

        nfc_eeprom_erase_start_session,
        nfc_eeprom_erase_write_max_size,
        nfc_eeprom_erase_erase_bytes,
        nfc_eeprom_erase_write_0_size,
        nfc_eeprom_erase_end_session
    };

    Delegate *_delegate;
    NFCEEPROMDriver *_driver;
    bool _initialized;

    nfc_eeprom_operation_t _current_op;
    ac_buffer_t _ndef_buffer_reader;
    size_t _ndef_buffer_read_sz;
    uint32_t _eeprom_address;
    nfc_err_t _operation_result;
};

/**
 * @}
 */


} // namespace nfc
} // namespace mbed

#endif