hw_rng.c
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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-04-25 tyx the first version
*/
#include <rtthread.h>
#include <rtdevice.h>
#include <hw_rng.h>
/* Used to save default RNG Context */
static struct rt_hwcrypto_ctx *ctx_default;
/**
* @brief Creating RNG Context
*
* @param device Hardware crypto device
*
* @return RNG context
*/
struct rt_hwcrypto_ctx *rt_hwcrypto_rng_create(struct rt_hwcrypto_device *device)
{
struct rt_hwcrypto_ctx *ctx;
ctx = rt_hwcrypto_ctx_create(device, HWCRYPTO_TYPE_RNG, sizeof(struct hwcrypto_rng));
return ctx;
}
/**
* @brief Destroy RNG Context
*
* @param ctx RNG context
*/
void rt_hwcrypto_rng_destroy(struct rt_hwcrypto_ctx *ctx)
{
/* Destroy the defaule RNG Context ? */
if (ctx == ctx_default)
{
ctx_default = RT_NULL;
}
rt_hwcrypto_ctx_destroy(ctx);
}
/**
* @brief Setting RNG default devices
*
* @return RT_EOK on success.
*/
rt_err_t rt_hwcrypto_rng_default(struct rt_hwcrypto_device *device)
{
struct rt_hwcrypto_ctx *tmp_ctx;
/* if device is null, destroy default RNG Context */
if (device == RT_NULL)
{
if (ctx_default)
{
rt_hwcrypto_rng_destroy(ctx_default);
ctx_default = RT_NULL;
}
return RT_EOK;
}
/* Try create RNG Context */
tmp_ctx = rt_hwcrypto_rng_create(device);
if (tmp_ctx == RT_NULL)
{
return -RT_ERROR;
}
/* create RNG Context success, update default RNG Context */
rt_hwcrypto_rng_destroy(ctx_default);
ctx_default = tmp_ctx;
return RT_EOK;
}
/**
* @brief Getting Random Numbers from RNG Context
*
* @param ctx RNG context
*
* @return Random number
*/
rt_uint32_t rt_hwcrypto_rng_update_ctx(struct rt_hwcrypto_ctx *ctx)
{
if (ctx)
{
return ((struct hwcrypto_rng *)ctx)->ops->update((struct hwcrypto_rng *)ctx);
}
return 0;
}
/**
* @brief Return a random number
*
* @return Random number
*/
rt_uint32_t rt_hwcrypto_rng_update(void)
{
/* Default device does not exist ? */
if (ctx_default == RT_NULL)
{
/* try create Context from default device */
rt_hwcrypto_rng_default(rt_hwcrypto_dev_default());
}
return rt_hwcrypto_rng_update_ctx(ctx_default);
}