/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 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 "gpio_api.h"

#define CRC16
#include "crc.h"
#include "fsl_rtc.h"
#include "fsl_clock_config.h"

// called before main
void mbed_sdk_init()
{
    rtc_config_t rtc_basic_config;
    uint32_t u32cTPR_counter = 0;

    BOARD_BootClockRUN();

    CLOCK_EnableClock(kCLOCK_Rtc0);

    /* Check if the Rtc oscillator is enabled */
    if ((RTC->CR & RTC_CR_OSCE_MASK) == 0u) {
        /*Init the RTC with default configuration*/
        RTC_GetDefaultConfig(&rtc_basic_config);

        /* Setup the 32K RTC OSC */
        RTC_Init(RTC, &rtc_basic_config);

        /* Enable the RTC 32KHz oscillator */
        RTC->CR |= RTC_CR_OSCE_MASK;

        /* Start the RTC time counter */
        RTC_StartTimer(RTC);

        /* Verify TPR register reaches 4096 counts */
        while (u32cTPR_counter < 4096) {
            u32cTPR_counter = RTC->TPR;
        }
        /* 32kHz Oscillator is ready. */
        RTC_Deinit(RTC);
    }

    CLOCK_DisableClock(kCLOCK_Rtc0);
}

// Change the NMI pin to an input. This allows NMI pin to
//  be used as a low power mode wakeup.  The application will
//  need to change the pin back to NMI_b or wakeup only occurs once!
void NMI_Handler(void)
{
    gpio_t gpio;
    gpio_init_in(&gpio, PTA4);
}

// Provide ethernet devices with a semi-unique MAC address from the UUID
void mbed_mac_address(char *mac)
{
    uint16_t MAC[3];                        // 3 16 bits words for the MAC

    // get UID via SIM_UID macros defined in the K64F MCU CMSIS header file
    uint32_t UID[4];
    UID[0] = SIM->UIDH;
    UID[1] = SIM->UIDMH;
    UID[2] = SIM->UIDML;
    UID[3] = SIM->UIDL;

    // generate three CRC16's using different slices of the UUID
    MAC[0] = crcSlow((const uint8_t *)UID, 8);  // most significant half-word
    MAC[1] = crcSlow((const uint8_t *)UID, 12);
    MAC[2] = crcSlow((const uint8_t *)UID, 16); // least significant half word

    // The network stack expects an array of 6 bytes
    // so we copy, and shift and copy from the half-word array to the byte array
    mac[0] = MAC[0] >> 8;
    mac[1] = MAC[0];
    mac[2] = MAC[1] >> 8;
    mac[3] = MAC[1];
    mac[4] = MAC[2] >> 8;
    mac[5] = MAC[2];

    // We want to force bits [1:0] of the most significant byte [0]
    // to be "10"
    // http://en.wikipedia.org/wiki/MAC_address

    mac[0] |= 0x02; // force bit 1 to a "1" = "Locally Administered"
    mac[0] &= 0xFE; // force bit 0 to a "0" = Unicast

}