163 lines
7.0 KiB
C
163 lines
7.0 KiB
C
|
// #################################################################################################
|
||
|
|
// # << NEORV32: neorv32_trng.c - True Random Number Generator (TRNG) HW Driver >> #
|
||
|
|
// # ********************************************************************************************* #
|
||
|
|
// # BSD 3-Clause License #
|
||
|
|
// # #
|
||
|
|
// # Copyright (c) 2023, Stephan Nolting. 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 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. #
|
||
|
|
// # ********************************************************************************************* #
|
||
|
|
// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
|
||
|
|
// #################################################################################################
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* @file neorv32_trng.c
|
||
|
|
* @brief True Random Number Generator (TRNG) HW driver source file.
|
||
|
|
*
|
||
|
|
* @note These functions should only be used if the TRNG unit was synthesized (IO_TRNG_EN = true).
|
||
|
|
**************************************************************************/
|
||
|
|
|
||
|
|
#include "neorv32.h"
|
||
|
|
#include "neorv32_trng.h"
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Check if TRNG unit was synthesized.
|
||
|
|
*
|
||
|
|
* @return 0 if TRNG was not synthesized, 1 if TRNG is available.
|
||
|
|
**************************************************************************/
|
||
|
|
int neorv32_trng_available(void) {
|
||
|
|
|
||
|
|
if (NEORV32_SYSINFO->SOC & (1 << SYSINFO_SOC_IO_TRNG)) {
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Reset, configure and enable TRNG.
|
||
|
|
*
|
||
|
|
* @param[in] irq_mask Interrupt configuration mask (CTRL's irq_* bits).
|
||
|
|
**************************************************************************/
|
||
|
|
void neorv32_trng_enable(uint32_t irq_mask) {
|
||
|
|
|
||
|
|
int i;
|
||
|
|
|
||
|
|
NEORV32_TRNG->CTRL = 0; // reset
|
||
|
|
|
||
|
|
// wait for all internal components to reset
|
||
|
|
for (i=0; i<256; i++) {
|
||
|
|
asm volatile ("nop");
|
||
|
|
}
|
||
|
|
|
||
|
|
NEORV32_TRNG->CTRL = 1 << TRNG_CTRL_EN; // activate
|
||
|
|
|
||
|
|
// "warm-up"
|
||
|
|
for (i=0; i<256; i++) {
|
||
|
|
asm volatile ("nop");
|
||
|
|
}
|
||
|
|
|
||
|
|
// flush random data "pool"
|
||
|
|
neorv32_trng_fifo_clear();
|
||
|
|
|
||
|
|
// set interrupt mask
|
||
|
|
const uint32_t tmp = (1 << TRNG_CTRL_IRQ_FIFO_NEMPTY) |
|
||
|
|
(1 << TRNG_CTRL_IRQ_FIFO_HALF) |
|
||
|
|
(1 << TRNG_CTRL_IRQ_FIFO_FULL);
|
||
|
|
NEORV32_TRNG->CTRL |= irq_mask & tmp;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Reset and disable TRNG.
|
||
|
|
**************************************************************************/
|
||
|
|
void neorv32_trng_disable(void) {
|
||
|
|
|
||
|
|
NEORV32_TRNG->CTRL = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Flush TRNG random data FIFO.
|
||
|
|
**************************************************************************/
|
||
|
|
void neorv32_trng_fifo_clear(void) {
|
||
|
|
|
||
|
|
NEORV32_TRNG->CTRL |= 1 << TRNG_CTRL_FIFO_CLR; // bit auto clears
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Get TRNG FIFO depth.
|
||
|
|
*
|
||
|
|
* @return TRNG FIFO size (number of entries).
|
||
|
|
**************************************************************************/
|
||
|
|
int neorv32_trng_get_fifo_depth(void) {
|
||
|
|
|
||
|
|
uint32_t tmp = (NEORV32_TRNG->CTRL >> TRNG_CTRL_FIFO_LSB) & 0x0f;
|
||
|
|
return (int)(1 << tmp);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Get random data byte from TRNG.
|
||
|
|
*
|
||
|
|
* @param[in,out] data uint8_t pointer for storing random data byte. Will be set to zero if no valid data available.
|
||
|
|
* @return Data is valid when 0 and invalid otherwise.
|
||
|
|
**************************************************************************/
|
||
|
|
int neorv32_trng_get(uint8_t *data) {
|
||
|
|
|
||
|
|
uint32_t tmp = NEORV32_TRNG->CTRL;
|
||
|
|
*data = (uint8_t)(tmp >> TRNG_CTRL_DATA_LSB);
|
||
|
|
|
||
|
|
if (tmp & (1<<TRNG_CTRL_VALID)) { // output data valid?
|
||
|
|
return 0; // valid data
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/**********************************************************************//**
|
||
|
|
* Check if TRNG is implemented using SIMULATION mode.
|
||
|
|
*
|
||
|
|
* @warning In simulation mode the physical entropy source is replaced by a PRNG (LFSR) with very bad random quality.
|
||
|
|
*
|
||
|
|
* @return Simulation mode active when not zero.
|
||
|
|
**************************************************************************/
|
||
|
|
int neorv32_trng_check_sim_mode(void) {
|
||
|
|
|
||
|
|
if (NEORV32_TRNG->CTRL & (1<<TRNG_CTRL_SIM_MODE)) {
|
||
|
|
return -1; // simulation mode (PRNG)
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return 0; // real TRUE random number generator mode
|
||
|
|
}
|
||
|
|
}
|