400 lines
13 KiB
C
400 lines
13 KiB
C
/**
|
|
******************************************************************************
|
|
* @file stm32f4xx_rng.c
|
|
* @author MCD Application Team
|
|
* @version V1.0.0
|
|
* @date 30-September-2011
|
|
* @brief This file provides firmware functions to manage the following
|
|
* functionalities of the Random Number Generator (RNG) peripheral:
|
|
* - Initialization and Configuration
|
|
* - Get 32 bit Random number
|
|
* - Interrupts and flags management
|
|
*
|
|
* @verbatim
|
|
*
|
|
* ===================================================================
|
|
* How to use this driver
|
|
* ===================================================================
|
|
* 1. Enable The RNG controller clock using
|
|
* RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_RNG, ENABLE) function.
|
|
*
|
|
* 2. Activate the RNG peripheral using RNG_Cmd() function.
|
|
*
|
|
* 3. Wait until the 32 bit Random number Generator contains a valid
|
|
* random data (using polling/interrupt mode). For more details,
|
|
* refer to "Interrupts and flags management functions" module
|
|
* description.
|
|
*
|
|
* 4. Get the 32 bit Random number using RNG_GetRandomNumber() function
|
|
*
|
|
* 5. To get another 32 bit Random number, go to step 3.
|
|
*
|
|
*
|
|
*
|
|
* @endverbatim
|
|
*
|
|
******************************************************************************
|
|
* @attention
|
|
*
|
|
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
|
|
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
|
|
* TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
|
|
* DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
|
|
* FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
|
|
* CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
|
|
*
|
|
* <h2><center>© COPYRIGHT 2011 STMicroelectronics</center></h2>
|
|
******************************************************************************
|
|
*/
|
|
|
|
/* Includes ------------------------------------------------------------------*/
|
|
#include "stm32f4xx_rng.h"
|
|
#include "stm32f4xx_rcc.h"
|
|
|
|
/** @addtogroup STM32F4xx_StdPeriph_Driver
|
|
* @{
|
|
*/
|
|
|
|
/** @defgroup RNG
|
|
* @brief RNG driver modules
|
|
* @{
|
|
*/
|
|
|
|
/* Private typedef -----------------------------------------------------------*/
|
|
/* Private define ------------------------------------------------------------*/
|
|
/* Private macro -------------------------------------------------------------*/
|
|
/* Private variables ---------------------------------------------------------*/
|
|
/* Private function prototypes -----------------------------------------------*/
|
|
/* Private functions ---------------------------------------------------------*/
|
|
|
|
/** @defgroup RNG_Private_Functions
|
|
* @{
|
|
*/
|
|
|
|
/** @defgroup RNG_Group1 Initialization and Configuration functions
|
|
* @brief Initialization and Configuration functions
|
|
*
|
|
@verbatim
|
|
===============================================================================
|
|
Initialization and Configuration functions
|
|
===============================================================================
|
|
This section provides functions allowing to
|
|
- Initialize the RNG peripheral
|
|
- Enable or disable the RNG peripheral
|
|
|
|
@endverbatim
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @brief Deinitializes the RNG peripheral registers to their default reset values.
|
|
* @param None
|
|
* @retval None
|
|
*/
|
|
void RNG_DeInit(void)
|
|
{
|
|
/* Enable RNG reset state */
|
|
RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, ENABLE);
|
|
|
|
/* Release RNG from reset state */
|
|
RCC_AHB2PeriphResetCmd(RCC_AHB2Periph_RNG, DISABLE);
|
|
}
|
|
|
|
/**
|
|
* @brief Enables or disables the RNG peripheral.
|
|
* @param NewState: new state of the RNG peripheral.
|
|
* This parameter can be: ENABLE or DISABLE.
|
|
* @retval None
|
|
*/
|
|
void RNG_Cmd(FunctionalState NewState)
|
|
{
|
|
/* Check the parameters */
|
|
assert_param(IS_FUNCTIONAL_STATE(NewState));
|
|
|
|
if (NewState != DISABLE)
|
|
{
|
|
/* Enable the RNG */
|
|
RNG->CR |= RNG_CR_RNGEN;
|
|
}
|
|
else
|
|
{
|
|
/* Disable the RNG */
|
|
RNG->CR &= ~RNG_CR_RNGEN;
|
|
}
|
|
}
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @defgroup RNG_Group2 Get 32 bit Random number function
|
|
* @brief Get 32 bit Random number function
|
|
*
|
|
|
|
@verbatim
|
|
===============================================================================
|
|
Get 32 bit Random number function
|
|
===============================================================================
|
|
This section provides a function allowing to get the 32 bit Random number
|
|
|
|
@note Before to call this function you have to wait till DRDY flag is set,
|
|
using RNG_GetFlagStatus(RNG_FLAG_DRDY) function.
|
|
|
|
@endverbatim
|
|
* @{
|
|
*/
|
|
|
|
|
|
/**
|
|
* @brief Returns a 32-bit random number.
|
|
*
|
|
* @note Before to call this function you have to wait till DRDY (data ready)
|
|
* flag is set, using RNG_GetFlagStatus(RNG_FLAG_DRDY) function.
|
|
* @note Each time the the Random number data is read (using RNG_GetRandomNumber()
|
|
* function), the RNG_FLAG_DRDY flag is automatically cleared.
|
|
* @note In the case of a seed error, the generation of random numbers is
|
|
* interrupted for as long as the SECS bit is '1'. If a number is
|
|
* available in the RNG_DR register, it must not be used because it may
|
|
* not have enough entropy. In this case, it is recommended to clear the
|
|
* SEIS bit(using RNG_ClearFlag(RNG_FLAG_SECS) function), then disable
|
|
* and enable the RNG peripheral (using RNG_Cmd() function) to
|
|
* reinitialize and restart the RNG.
|
|
* @note In the case of a clock error, the RNG is no more able to generate
|
|
* random numbers because the PLL48CLK clock is not correct. User have
|
|
* to check that the clock controller is correctly configured to provide
|
|
* the RNG clock and clear the CEIS bit (using RNG_ClearFlag(RNG_FLAG_CECS)
|
|
* function) . The clock error has no impact on the previously generated
|
|
* random numbers, and the RNG_DR register contents can be used.
|
|
*
|
|
* @param None
|
|
* @retval 32-bit random number.
|
|
*/
|
|
uint32_t RNG_GetRandomNumber(void)
|
|
{
|
|
/* Return the 32 bit random number from the DR register */
|
|
return RNG->DR;
|
|
}
|
|
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/** @defgroup RNG_Group3 Interrupts and flags management functions
|
|
* @brief Interrupts and flags management functions
|
|
*
|
|
@verbatim
|
|
===============================================================================
|
|
Interrupts and flags management functions
|
|
===============================================================================
|
|
|
|
This section provides functions allowing to configure the RNG Interrupts and
|
|
to get the status and clear flags and Interrupts pending bits.
|
|
|
|
The RNG provides 3 Interrupts sources and 3 Flags:
|
|
|
|
Flags :
|
|
----------
|
|
1. RNG_FLAG_DRDY : In the case of the RNG_DR register contains valid
|
|
random data. it is cleared by reading the valid data
|
|
(using RNG_GetRandomNumber() function).
|
|
|
|
2. RNG_FLAG_CECS : In the case of a seed error detection.
|
|
|
|
3. RNG_FLAG_SECS : In the case of a clock error detection.
|
|
|
|
|
|
Interrupts :
|
|
------------
|
|
if enabled, an RNG interrupt is pending :
|
|
|
|
1. In the case of the RNG_DR register contains valid random data.
|
|
This interrupt source is cleared once the RNG_DR register has been read
|
|
(using RNG_GetRandomNumber() function) until a new valid value is
|
|
computed.
|
|
|
|
or
|
|
2. In the case of a seed error : One of the following faulty sequences has
|
|
been detected:
|
|
- More than 64 consecutive bits at the same value (0 or 1)
|
|
- More than 32 consecutive alternance of 0 and 1 (0101010101...01)
|
|
This interrupt source is cleared using RNG_ClearITPendingBit(RNG_IT_SEI)
|
|
function.
|
|
|
|
or
|
|
3. In the case of a clock error : the PLL48CLK (RNG peripheral clock source)
|
|
was not correctly detected (fPLL48CLK< fHCLK/16).
|
|
This interrupt source is cleared using RNG_ClearITPendingBit(RNG_IT_CEI)
|
|
function.
|
|
@note In this case, User have to check that the clock controller is
|
|
correctly configured to provide the RNG clock.
|
|
|
|
Managing the RNG controller events :
|
|
------------------------------------
|
|
The user should identify which mode will be used in his application to manage
|
|
the RNG controller events: Polling mode or Interrupt mode.
|
|
|
|
1. In the Polling Mode it is advised to use the following functions:
|
|
- RNG_GetFlagStatus() : to check if flags events occur.
|
|
- RNG_ClearFlag() : to clear the flags events.
|
|
|
|
@note RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag(). it is cleared only
|
|
by reading the Random number data.
|
|
|
|
2. In the Interrupt Mode it is advised to use the following functions:
|
|
- RNG_ITConfig() : to enable or disable the interrupt source.
|
|
- RNG_GetITStatus() : to check if Interrupt occurs.
|
|
- RNG_ClearITPendingBit() : to clear the Interrupt pending Bit
|
|
(corresponding Flag).
|
|
|
|
|
|
@endverbatim
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @brief Enables or disables the RNG interrupt.
|
|
* @note The RNG provides 3 interrupt sources,
|
|
* - Computed data is ready event (DRDY), and
|
|
* - Seed error Interrupt (SEI) and
|
|
* - Clock error Interrupt (CEI),
|
|
* all these interrupts sources are enabled by setting the IE bit in
|
|
* CR register. However, each interrupt have its specific status bit
|
|
* (see RNG_GetITStatus() function) and clear bit except the DRDY event
|
|
* (see RNG_ClearITPendingBit() function).
|
|
* @param NewState: new state of the RNG interrupt.
|
|
* This parameter can be: ENABLE or DISABLE.
|
|
* @retval None
|
|
*/
|
|
void RNG_ITConfig(FunctionalState NewState)
|
|
{
|
|
/* Check the parameters */
|
|
assert_param(IS_FUNCTIONAL_STATE(NewState));
|
|
|
|
if (NewState != DISABLE)
|
|
{
|
|
/* Enable the RNG interrupt */
|
|
RNG->CR |= RNG_CR_IE;
|
|
}
|
|
else
|
|
{
|
|
/* Disable the RNG interrupt */
|
|
RNG->CR &= ~RNG_CR_IE;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Checks whether the specified RNG flag is set or not.
|
|
* @param RNG_FLAG: specifies the RNG flag to check.
|
|
* This parameter can be one of the following values:
|
|
* @arg RNG_FLAG_DRDY: Data Ready flag.
|
|
* @arg RNG_FLAG_CECS: Clock Error Current flag.
|
|
* @arg RNG_FLAG_SECS: Seed Error Current flag.
|
|
* @retval The new state of RNG_FLAG (SET or RESET).
|
|
*/
|
|
FlagStatus RNG_GetFlagStatus(uint8_t RNG_FLAG)
|
|
{
|
|
FlagStatus bitstatus = RESET;
|
|
/* Check the parameters */
|
|
assert_param(IS_RNG_GET_FLAG(RNG_FLAG));
|
|
|
|
/* Check the status of the specified RNG flag */
|
|
if ((RNG->SR & RNG_FLAG) != (uint8_t)RESET)
|
|
{
|
|
/* RNG_FLAG is set */
|
|
bitstatus = SET;
|
|
}
|
|
else
|
|
{
|
|
/* RNG_FLAG is reset */
|
|
bitstatus = RESET;
|
|
}
|
|
/* Return the RNG_FLAG status */
|
|
return bitstatus;
|
|
}
|
|
|
|
|
|
/**
|
|
* @brief Clears the RNG flags.
|
|
* @param RNG_FLAG: specifies the flag to clear.
|
|
* This parameter can be any combination of the following values:
|
|
* @arg RNG_FLAG_CECS: Clock Error Current flag.
|
|
* @arg RNG_FLAG_SECS: Seed Error Current flag.
|
|
* @note RNG_FLAG_DRDY can not be cleared by RNG_ClearFlag() function.
|
|
* This flag is cleared only by reading the Random number data (using
|
|
* RNG_GetRandomNumber() function).
|
|
* @retval None
|
|
*/
|
|
void RNG_ClearFlag(uint8_t RNG_FLAG)
|
|
{
|
|
/* Check the parameters */
|
|
assert_param(IS_RNG_CLEAR_FLAG(RNG_FLAG));
|
|
/* Clear the selected RNG flags */
|
|
RNG->SR = ~(uint32_t)(((uint32_t)RNG_FLAG) << 4);
|
|
}
|
|
|
|
/**
|
|
* @brief Checks whether the specified RNG interrupt has occurred or not.
|
|
* @param RNG_IT: specifies the RNG interrupt source to check.
|
|
* This parameter can be one of the following values:
|
|
* @arg RNG_IT_CEI: Clock Error Interrupt.
|
|
* @arg RNG_IT_SEI: Seed Error Interrupt.
|
|
* @retval The new state of RNG_IT (SET or RESET).
|
|
*/
|
|
ITStatus RNG_GetITStatus(uint8_t RNG_IT)
|
|
{
|
|
ITStatus bitstatus = RESET;
|
|
/* Check the parameters */
|
|
assert_param(IS_RNG_GET_IT(RNG_IT));
|
|
|
|
/* Check the status of the specified RNG interrupt */
|
|
if ((RNG->SR & RNG_IT) != (uint8_t)RESET)
|
|
{
|
|
/* RNG_IT is set */
|
|
bitstatus = SET;
|
|
}
|
|
else
|
|
{
|
|
/* RNG_IT is reset */
|
|
bitstatus = RESET;
|
|
}
|
|
/* Return the RNG_IT status */
|
|
return bitstatus;
|
|
}
|
|
|
|
|
|
/**
|
|
* @brief Clears the RNG interrupt pending bit(s).
|
|
* @param RNG_IT: specifies the RNG interrupt pending bit(s) to clear.
|
|
* This parameter can be any combination of the following values:
|
|
* @arg RNG_IT_CEI: Clock Error Interrupt.
|
|
* @arg RNG_IT_SEI: Seed Error Interrupt.
|
|
* @retval None
|
|
*/
|
|
void RNG_ClearITPendingBit(uint8_t RNG_IT)
|
|
{
|
|
/* Check the parameters */
|
|
assert_param(IS_RNG_IT(RNG_IT));
|
|
|
|
/* Clear the selected RNG interrupt pending bit */
|
|
RNG->SR = (uint8_t)~RNG_IT;
|
|
}
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
|
|
/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/
|