/*----------------------------------------------------------------------------
 * Copyright (c) Huawei Technologies Co., Ltd. 2013-2020. All rights reserved.
 * Description: Hal Rng
 * Author: Huawei LiteOS Team
 * Create: 2013-01-01
 * 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. Neither the name of the copyright holder nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific prior written
 * permission.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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 <string.h>
#include "hal_rng.h"
#include "stm32l4xx.h"
#include "stm32l4xx_hal_rng.h"

#ifdef HAL_RNG_MODULE_ENABLED

RNG_HandleTypeDef g_rng_handle;

void hal_rng_config(void)
{
    __HAL_RCC_RNG_CLK_ENABLE();
    g_rng_handle.Instance = RNG;
    (void)HAL_RNG_Init(&g_rng_handle);
}

int hal_rng_generate_number()
{
    uint32_t random_number;

    if (HAL_RNG_GenerateRandomNumber(&g_rng_handle, &random_number) != HAL_OK) {
        return 0U;
    }

    return (int)random_number;
}

int hal_rng_generate_buffer(void *buf, size_t len)
{
    size_t i;
    uint32_t random_number;
    uint8_t *pbuf;

    if (buf == NULL) {
        return -1;
    }

    pbuf = (uint8_t *)buf;

    for (i = 0; i < len; i += sizeof(uint32_t)) {
        if (HAL_RNG_GenerateRandomNumber(&g_rng_handle, &random_number) != HAL_OK) {
            return -1;
        }
        memcpy(pbuf + i, &random_number, sizeof(uint32_t) > len - i ? len - i : sizeof(uint32_t));
    }

    return 0;
}

#endif /* HAL_RNG_MODULE_ENABLED */
