From e72ef8c943b3a335fe4354e6451be99ab1346081 Mon Sep 17 00:00:00 2001
From: Giovanni Di Sirio <gdisirio@gmail.com>
Date: Sun, 7 Oct 2018 07:58:29 +0000
Subject: STM32 TRNG driver, not tested yet.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@12342 110e8d01-0319-4d1e-a829-52ad28d1bb01
---
 os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c | 179 ++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c

(limited to 'os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c')

diff --git a/os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c b/os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c
new file mode 100644
index 000000000..ac6d39838
--- /dev/null
+++ b/os/hal/ports/STM32/LLD/RNGv1/hal_trng_lld.c
@@ -0,0 +1,179 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/**
+ * @file    hal_trng_lld.c
+ * @brief   STM32 TRNG subsystem low level driver source.
+ *
+ * @addtogroup TRNG
+ * @{
+ */
+
+#include "hal.h"
+
+#if (HAL_USE_TRNG == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   TRNGD1 driver identifier.
+ */
+#if (STM32_TRNG_USE_RNG1 == TRUE) || defined(__DOXYGEN__)
+TRNGDriver TRNGD1;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables and types.                                         */
+/*===========================================================================*/
+
+static const TRNGConfig default_cfg = {0};
+
+/*===========================================================================*/
+/* Driver local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Low level TRNG driver initialization.
+ *
+ * @notapi
+ */
+void trng_lld_init(void) {
+
+#if STM32_TRNG_USE_RNG1 == TRUE
+  /* Driver initialization.*/
+  trngObjectInit(&TRNGD1);
+  TRNGD1.rng = RNG;
+#endif
+}
+
+/**
+ * @brief   Configures and activates the TRNG peripheral.
+ *
+ * @param[in] trngp      pointer to the @p TRNGDriver object
+ *
+ * @notapi
+ */
+void trng_lld_start(TRNGDriver *trngp) {
+
+  /* There is no real configuration but setting up a valid pointer anyway.*/
+  if (trngp->config == NULL) {
+    trngp->config = &default_cfg;
+  }
+
+  if (trngp->state == TRNG_STOP) {
+    /* Enables the peripheral.*/
+#if STM32_TRNG_USE_RNG1 == TRUE
+    if (&TRNGD1 == trngp) {
+      rccEnableRNG(false);
+    }
+#endif
+  }
+  /* Configures the peripheral.*/
+  trngp->rng->CR |= RNG_CR_RNGEN;
+}
+
+/**
+ * @brief   Deactivates the TRNG peripheral.
+ *
+ * @param[in] trngp      pointer to the @p TRNGDriver object
+ *
+ * @notapi
+ */
+void trng_lld_stop(TRNGDriver *trngp) {
+
+  if (trngp->state == TRNG_READY) {
+    /* Resets the peripheral.*/
+    trngp->rng->CR &= ~RNG_CR_RNGEN;
+
+    /* Disables the peripheral.*/
+#if STM32_TRNG_USE_RNG1 == TRUE
+    if (&TRNGD1 == trngp) {
+      rccDisableRNG();
+    }
+#endif
+  }
+}
+
+/**
+ * @brief   True random numbers generator.
+ * @note    The function is blocking and likely performs polled waiting
+ *          inside the low level implementation.
+ *
+ * @param[in] trngp             pointer to the @p TRNGDriver object
+ * @param[in] size              size of output buffer
+ * @param[out] out              output buffer
+ * @return                      The operation status.
+ * @retval false                if a random number has been generated.
+ * @retval true                 if an HW error occurred.
+ *
+ * @api
+ */
+bool trng_lld_generate(TRNGDriver *trngp, size_t size, uint8_t *out) {
+
+  while (true) {
+    uint32_t r, tmo;
+    size_t i;
+
+    /* Waiting for error conditions to be cleared.*/
+    tmo = STM32_TRNG_ERROR_CLEAR_ATTEMPTS;
+    while ((tmo > 0) && ((trngp->rng->SR & (RNG_SR_CECS | RNG_SR_SECS)) != 0)) {
+      tmo--;
+      if (tmo == 0) {
+        return true;
+      }
+    }
+
+    /* Waiting for a random number in data register.*/
+    tmo = STM32_DATA_FETCH_ATTEMPTS;
+    while ((tmo > 0) && ((trngp->rng->SR & RNG_SR_DRDY) != 0)) {
+      tmo--;
+      if (tmo == 0) {
+        return true;
+      }
+    }
+
+    /* Getting the generated random number.*/
+    r = trngp->rng->DR;
+
+    /* Writing in the output buffer.*/
+    for (i = 0; i < sizeof (uint32_t) / sizeof (uint8_t); i++) {
+      *out++ = (uint8_t)r;
+      r = r >> 8;
+      size--;
+      if (size == 0) {
+        return false;
+      }
+    }
+  }
+}
+
+#endif /* HAL_USE_TRNG == TRUE */
+
+/** @} */
-- 
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