/*
 * Copyright (c) 2019-2023 Beijing Hanwei Innovation Technology Ltd. Co. and
 * its subsidiaries and affiliates (collectly called MKSEMI).
 *
 * 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, except as embedded into an MKSEMI
 *    integrated circuit in a product or a software update for such product,
 *    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. Neither the name of MKSEMI nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    MKSEMI integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be
 *    reverse engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY MKSEMI "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL MKSEMI OR CONTRIBUTORS 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.
 */

#include "mk_trng.h"
#include "mk_clock.h"
#include "mk_reset.h"

static struct TRNG_HANDLE_T trng_handle = {
    .base = TRNG,
    .irq = TRNG_IRQn,
    .cfg = TRNG_CFG_1LSB_VN,
    .data = 0,
    .number = 0,
    .int_en = false,
    .callback = NULL,
};

int trng_open(void)
{
    // enable TRNG clock
    clock_enable(CLOCK_TRNG);
    reset_module(RESET_MODULE_TRNG);

    trng_handle.base->CTRL0 = TRNG_CTRL0_LSB_CFG(trng_handle.cfg);

#if TRNG_INT_MODE_EN
    if (trng_handle.int_en)
    {
        NVIC_SetPriority(trng_handle.irq, IRQ_PRIORITY_NORMAL);
        NVIC_ClearPendingIRQ(trng_handle.irq);
        NVIC_EnableIRQ(trng_handle.irq);
    }
#endif

    trng_handle.state = TRNG_STATE_READY;
    return DRV_OK;
}

int trng_close(void)
{
#if TRNG_INT_MODE_EN
    if (trng_handle.int_en)
    {
        NVIC_DisableIRQ(trng_handle.irq);
        NVIC_ClearPendingIRQ(trng_handle.irq);
    }
#endif

    // disable TRNG clock
    clock_disable(CLOCK_TRNG);

    trng_handle.state = TRNG_STATE_RESET;
    return DRV_OK;
}

int trng_get(uint32_t *data, uint32_t number, drv_callback_t callback)
{
    uint32_t lock = int_lock();

    // update state
    switch (trng_handle.state)
    {
    case TRNG_STATE_READY:
        trng_handle.state = TRNG_STATE_BUSY;
        break;
    case TRNG_STATE_BUSY:
        int_unlock(lock);
        return DRV_BUSY;
    case TRNG_STATE_RESET:
    case TRNG_STATE_TIMEOUT:
    case TRNG_STATE_ERROR:
        int_unlock(lock);
        return DRV_ERROR;
    }

    trng_handle.data = data;
    trng_handle.number = number;
    trng_handle.count = number;
    trng_handle.callback = callback;

    int_unlock(lock);

    if (trng_handle.int_en)
    {
#if TRNG_INT_MODE_EN
        // enable interrupt
        trng_handle.base->INTR_EN = TRNG_INTR_EN_MSK;
        trng_handle.base->CTRL1 = TRNG_CTRL1_TRNG_REQ_MSK;
#endif
    }
    else
    {
#if TRNG_POLL_MODE_EN
        // polling
        while (trng_handle.count > 0)
        {
            trng_handle.base->CTRL1 = TRNG_CTRL1_TRNG_REQ_MSK;
            while ((trng_handle.base->STATUS & TRNG_STATUS_DONE_MSK) == 0)
            {
            }

            for (uint8_t i = 0; i < 4; i++)
            {
                if (trng_handle.count)
                {
                    *trng_handle.data++ = trng_handle.base->DATA[i];
                    trng_handle.count--;
                }
                else
                {
                    break;
                }
            }
        }

        // update state
        trng_handle.state = TRNG_STATE_READY;

        if (trng_handle.callback)
        {
            trng_handle.callback(trng_handle.data - trng_handle.number, trng_handle.number);
        }
#endif
    }

    return DRV_OK;
}

void TRNG_IRQHandler(void)
{
#if TRNG_INT_MODE_EN
    trng_handle.base->INTR_CLR = TRNG_INTR_CLR_MSK;

    for (uint8_t i = 0; i < 4; i++)
    {
        if (trng_handle.count)
        {
            *trng_handle.data++ = trng_handle.base->DATA[i];
            trng_handle.count--;
        }
        else
        {
            break;
        }
    }

    if (trng_handle.count)
    {
        // continue
        trng_handle.base->CTRL1 = TRNG_CTRL1_TRNG_REQ_MSK;
    }
    else
    {
        // finished - update state
        trng_handle.state = TRNG_STATE_READY;
        if (trng_handle.callback)
        {
            trng_handle.callback(trng_handle.data - trng_handle.number, trng_handle.number);
        }
    }
#endif
}