From d9a3d8493cf1df85a7690737755e295de80e8578 Mon Sep 17 00:00:00 2001
From: Stephane D'Alu <sdalu@sdalu.com>
Date: Mon, 8 Feb 2016 23:45:59 +0100
Subject: Random Number Generator driver

---
 os/hal/ports/NRF51/NRF51822/rng_lld.c | 155 ++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 os/hal/ports/NRF51/NRF51822/rng_lld.c

(limited to 'os/hal/ports/NRF51/NRF51822/rng_lld.c')

diff --git a/os/hal/ports/NRF51/NRF51822/rng_lld.c b/os/hal/ports/NRF51/NRF51822/rng_lld.c
new file mode 100644
index 0000000..b22b9fc
--- /dev/null
+++ b/os/hal/ports/NRF51/NRF51822/rng_lld.c
@@ -0,0 +1,155 @@
+/*
+    RNG for ChibiOS - Copyright (C) 2016 Stephane D'Alu
+
+    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    NRF51/RNGv1/rng_lld.c
+ * @brief   NRF51 RNG subsystem low level driver source.
+ *
+ * @addtogroup RNG
+ * @{
+ */
+
+#include "hal.h"
+
+#if (HAL_USE_RNG == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions.                                                 */
+/*===========================================================================*/
+
+/**
+ * @brief   RNG default configuration.
+ */
+static const RNGConfig default_config = {
+    .digital_error_correction = 1,
+    .power_on_write           = 1,
+};
+
+/*===========================================================================*/
+/* Driver exported variables.                                                */
+/*===========================================================================*/
+
+/** @brief RNG1 driver identifier.*/
+#if NRF51_RNG_USE_RNG1 || defined(__DOXYGEN__)
+RNGDriver RNGD1;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Low level RNG driver initialization.
+ *
+ * @notapi
+ */
+void rng_lld_init(void) {
+  rngObjectInit(&RNGD1);
+  RNGD1.rng    = NRF_RNG;
+}
+
+/**
+ * @brief   Configures and activates the RNG peripheral.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @notapi
+ */
+void rng_lld_start(RNGDriver *rngp) {
+  if (rngp->config == NULL)
+    rngp->config = &default_config;
+
+  rngp->rng->POWER = 1;
+
+  if (rngp->config->digital_error_correction) 
+    rngp->rng->CONFIG |=  RNG_CONFIG_DERCEN_Msk;
+  else
+    rngp->rng->CONFIG &= ~RNG_CONFIG_DERCEN_Msk;
+
+  rngp->rng->INTENSET    = RNG_INTENSET_VALRDY_Msk;
+  rngp->rng->TASKS_START = 1;
+}
+
+
+/**
+ * @brief   Deactivates the RNG peripheral.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @notapi
+ */
+void rng_lld_stop(RNGDriver *rngp) {
+  rngp->rng->TASKS_STOP = 1;
+  rngp->rng->POWER = 0;
+}
+
+
+/**
+ * @brief   Write random bytes;
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ * @param[in] n         size of buf in bytes
+ * @param[in] buf       @p buffer location
+ *
+ * @notapi
+ */
+msg_t rng_lld_write(RNGDriver *rngp, uint8_t *buf, size_t n,
+		    systime_t timeout) {
+  size_t i;
+  if (n == 0)
+    return MSG_OK;
+
+  if (n == 1)
+	rngp->rng->SHORTS |= RNG_SHORTS_VALRDY_STOP_Msk;
+
+  
+
+  NRF_RNG->EVENTS_VALRDY = 0;
+    
+  for (i = 0 ; i < n ; i++) {
+    /* sleep until number is generated */
+    while (NRF_RNG->EVENTS_VALRDY == 0) {
+      /* enable wake up on events for __WFE CPU sleep */
+      SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
+      /* sleep until next event */
+      __SEV();
+      __WFE();
+      __WFE();
+    }
+
+    buf[i] = (char)NRF_RNG->VALUE;
+
+    NRF_RNG->EVENTS_VALRDY = 0;
+    nvicClearPending(RNG_IRQn);
+  }
+  return MSG_OK;
+}
+
+#endif /* HAL_USE_RNG */
+
+/** @} */
-- 
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