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/**
* @file drivers/entropy.h
*
* @brief Public APIs for the entropy driver.
*/
/*
* Copyright (c) 2016 ARM Ltd.
* Copyright (c) 2017 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_DRIVERS_ENTROPY_H_
#define ZEPHYR_INCLUDE_DRIVERS_ENTROPY_H_
/**
* @brief Entropy Interface
* @defgroup entropy_interface Entropy Interface
* @since 1.10
* @version 1.0.0
* @ingroup io_interfaces
* @{
*/
#include <errno.h>
#include <zephyr/types.h>
#include <zephyr/device.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @brief Driver is allowed to busy-wait for random data to be ready */
#define ENTROPY_BUSYWAIT BIT(0)
/**
* @typedef entropy_get_entropy_t
* @brief Callback API to get entropy.
*
* @note This call has to be thread safe to satisfy requirements
* of the random subsystem.
*
* See entropy_get_entropy() for argument description
*/
typedef int (*entropy_get_entropy_t)(const struct device *dev,
uint8_t *buffer,
uint16_t length);
/**
* @typedef entropy_get_entropy_isr_t
* @brief Callback API to get entropy from an ISR.
*
* See entropy_get_entropy_isr() for argument description
*/
typedef int (*entropy_get_entropy_isr_t)(const struct device *dev,
uint8_t *buffer,
uint16_t length,
uint32_t flags);
/**
* @brief Entropy driver API structure.
*
* This is the mandatory API any Entropy driver needs to expose.
*/
__subsystem struct entropy_driver_api {
entropy_get_entropy_t get_entropy;
entropy_get_entropy_isr_t get_entropy_isr;
};
/**
* @brief Fills a buffer with entropy. Blocks if required in order to
* generate the necessary random data.
*
* @param dev Pointer to the entropy device.
* @param buffer Buffer to fill with entropy.
* @param length Buffer length.
* @retval 0 on success.
* @retval -ERRNO errno code on error.
*/
__syscall int entropy_get_entropy(const struct device *dev,
uint8_t *buffer,
uint16_t length);
static inline int z_impl_entropy_get_entropy(const struct device *dev,
uint8_t *buffer,
uint16_t length)
{
const struct entropy_driver_api *api =
(const struct entropy_driver_api *)dev->api;
__ASSERT(api->get_entropy != NULL,
"Callback pointer should not be NULL");
return api->get_entropy(dev, buffer, length);
}
/**
* @brief Fills a buffer with entropy in a non-blocking or busy-wait manner.
* Callable from ISRs.
*
* @param dev Pointer to the device structure.
* @param buffer Buffer to fill with entropy.
* @param length Buffer length.
* @param flags Flags to modify the behavior of the call.
* @retval number of bytes filled with entropy or -error.
*/
static inline int entropy_get_entropy_isr(const struct device *dev,
uint8_t *buffer,
uint16_t length,
uint32_t flags)
{
const struct entropy_driver_api *api =
(const struct entropy_driver_api *)dev->api;
if (unlikely(!api->get_entropy_isr)) {
return -ENOTSUP;
}
return api->get_entropy_isr(dev, buffer, length, flags);
}
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#include <zephyr/syscalls/entropy.h>
#endif /* ZEPHYR_INCLUDE_DRIVERS_ENTROPY_H_ */