Driver for random number generator peripheral

meson.build

@@ -227,6 +227,7 @@ stm32f405_src = ['platform/mcu/STM32F4xx/boot/startup.cpp',
                  'platform/mcu/STM32F4xx/drivers/SPI2.c',
                  'platform/mcu/STM32F4xx/drivers/USART3.cpp',
                  'platform/mcu/STM32F4xx/drivers/flash.c',
+                 'platform/mcu/STM32F4xx/drivers/rng.c',
                  'platform/drivers/audio/stm32_dac.cpp',
                  'platform/drivers/audio/stm32_adc.cpp',
                  'platform/drivers/audio/stm32_pwm.cpp',
@@ -250,6 +251,7 @@ mk22fn512_src = ['platform/mcu/MK22FN512xxx12/boot/startup.cpp',
                  'platform/mcu/MK22FN512xxx12/drivers/gpio.c',
                  'platform/mcu/MK22FN512xxx12/drivers/delays.cpp',
                  'platform/mcu/MK22FN512xxx12/drivers/I2C0.c',
+                 'platform/mcu/MK22FN512xxx12/drivers/rng.c',
                  'platform/mcu/MK22FN512xxx12/drivers/usb/usb_device_cdc_acm.c',
                  'platform/mcu/MK22FN512xxx12/drivers/usb/usb_device_ch9.c',
                  'platform/mcu/MK22FN512xxx12/drivers/usb/usb_device_dci.c',
@@ -280,6 +282,7 @@ linux_platform_src = ['platform/targets/linux/emulator/emulator.c',
                       'platform/drivers/NVM/nvmem_linux.c',
                       'platform/drivers/GPS/GPS_linux.c',
                       'platform/mcu/x86_64/drivers/delays.c',
+                      'platform/mcu/x86_64/drivers/rng.cpp',
                       'platform/drivers/baseband/radio_linux.cpp',
                       'platform/drivers/audio/audio_linux.c',
                       'platform/targets/linux/platform.c',

openrtx/include/peripherals/rng.h

@@ -0,0 +1,55 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#ifndef RNG_H
+#define RNG_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Driver for Random Number Generator.
+ */
+
+/**
+ * Initialise the RNG driver.
+ */
+void rng_init();
+
+/**
+ * Shut down the RNG module.
+ */
+void rng_terminate();
+
+/**
+ * Generate a 32 bit random number.
+ *
+ * @return random number.
+ */
+uint32_t rng_get();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* INTERFACES_GPS_H */

platform/mcu/MK22FN512xxx12/drivers/rng.c

@@ -0,0 +1,41 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <peripherals/rng.h>
+#include <MK22F51212.h>
+
+void rng_init()
+{
+    SIM->SCGC6 |= SIM_SCGC6_RNGA(1);
+    RNG->CR    |= RNG_CR_GO(1);
+}
+
+void rng_terminate()
+{
+    SIM->SCGC6 &= ~SIM_SCGC6_RNGA(1);
+}
+
+uint32_t rng_get()
+{
+    // Wait until there is some data
+    while((RNG->SR & RNG_SR_OREG_LVL_MASK) == 0) ;
+
+    return RNG->OR;
+}

platform/mcu/STM32F4xx/drivers/rng.c

@@ -0,0 +1,76 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <interfaces/delays.h>
+#include <peripherals/rng.h>
+#include <stm32f4xx.h>
+#include <pthread.h>
+
+static uint32_t oldValue = 0;
+
+void rng_init()
+{
+    RCC->AHB2ENR |= RCC_AHB2ENR_RNGEN;
+    __DSB();
+}
+
+void rng_terminate()
+{
+    RCC->AHB2ENR &= ~RCC_AHB2ENR_RNGEN;
+    __DSB();
+}
+
+uint32_t rng_get()
+{
+    uint32_t value;
+
+    RNG->CR = RNG_CR_RNGEN;
+
+    /*
+     * The datasheet says that the RNG takes 40 clock cycles of the 48MHz
+     * clock to generate a number, that is around 0.83us. It has not much
+     * sense to put a delay here, we can just spin a bit and wait.
+     */
+    while(1)
+    {
+        uint32_t status = RNG->SR;
+
+        // Got a new number, return it only if different from the previous one
+        if((status & RNG_SR_DRDY) != 0)
+        {
+            value = RNG->DR;
+            if(value != oldValue)
+                break;
+        }
+
+        // Error, "power cycle" the RNG and retry
+        if((status & (RNG_SR_SECS | RNG_SR_CECS)) != 0)
+        {
+            RNG->CR = 0;
+            delayUs(1);
+            RNG->CR = RNG_CR_RNGEN;
+        }
+    }
+
+    RNG->CR = 0;
+    oldValue = value;
+
+    return value;
+}

platform/mcu/x86_64/drivers/rng.cpp

@@ -0,0 +1,44 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <peripherals/rng.h>
+#include <random>
+#include <limits>
+
+static std::mt19937 rng;
+
+void rng_init()
+{
+    std::random_device seed;
+    rng.seed(seed());
+}
+
+void rng_terminate()
+{
+
+}
+
+uint32_t rng_get()
+{
+    std::uniform_int_distribution< uint32_t >
+    distribution(0, std::numeric_limits<uint32_t>::max());
+
+    return distribution(rng);
+}