Random Number Generator driver

8 files changed, 671 insertions, 2 deletions

diff --git a/os/hal/hal.mk b/os/hal/hal.mk
index 013a8db..8ac84dd 100644
--- a/os/hal/hal.mk
+++ b/os/hal/hal.mk
@@ -4,6 +4,7 @@ HALSRC += ${CHIBIOS_CONTRIB}/os/hal/src/hal_community.c \
           ${CHIBIOS_CONTRIB}/os/hal/src/nand.c \

           ${CHIBIOS_CONTRIB}/os/hal/src/onewire.c \

           ${CHIBIOS_CONTRIB}/os/hal/src/eicu.c \

-          ${CHIBIOS_CONTRIB}/os/hal/src/crc.c

+          ${CHIBIOS_CONTRIB}/os/hal/src/crc.c \

+          ${CHIBIOS_CONTRIB}/os/hal/src/rng.c

 

 HALINC += ${CHIBIOS_CONTRIB}/os/hal/include

diff --git a/os/hal/include/hal_community.h b/os/hal/include/hal_community.h
index 426fadd..d11e4c9 100644
--- a/os/hal/include/hal_community.h
+++ b/os/hal/include/hal_community.h
@@ -32,6 +32,7 @@
 /* Normal drivers.*/

 #include "nand.h"

 #include "eicu.h"

+#include "rng.h"

 

 /* Complex drivers.*/

 #include "onewire.h"

diff --git a/os/hal/include/rng.h b/os/hal/include/rng.h
new file mode 100644
index 0000000..ab0e363
--- /dev/null
+++ b/os/hal/include/rng.h
@@ -0,0 +1,141 @@
+/*
+    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.
+*/
+
+#ifndef _RNG_H_
+#define _RNG_H_
+
+#if (HAL_USE_RNG == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver constants.                                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/**
+ * @name    Configuration options
+ * @{
+ */
+
+/**
+ * @brief   Enables the @p rngAcquireBus() and @p rngReleaseBus() APIs.
+ * @note    Disabling this option saves both code and data space.
+ */
+#if !defined(RNG_USE_MUTUAL_EXCLUSION) || defined(__DOXYGEN__)
+#define RNG_USE_MUTUAL_EXCLUSION        TRUE
+#endif
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+#if NRF51_RNG_USE_RNG1 != TRUE && RNGSW_USE_RNG1 != TRUE
+#error "RNG requires at least one LLD driver."
+#endif
+
+/*===========================================================================*/
+/* Driver data structures and types.                                         */
+/*===========================================================================*/
+
+/**
+ * @brief   Driver state machine possible states.
+ */
+typedef enum {
+  RNG_UNINIT,                /* Not initialized.                           */
+  RNG_STOP,                  /* Stopped.                                   */
+  RNG_READY,                 /* Ready.                                     */
+} rngstate_t;
+
+#include "rng_lld.h"
+//#include "rngsw.h" /* Include software LL driver */
+
+
+/*===========================================================================*/
+/* Driver macros.                                                            */
+/*===========================================================================*/
+
+/**
+ * @name    Low level driver helper macros
+ * @{
+ */
+
+/**
+ * @brief   Wakes up the waiting thread.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @notapi
+ */
+#define _rng_wakeup_isr(rngp) {                                             \
+  osalSysLockFromISR();                                                     \
+  osalThreadResumeI(&(rngp)->thread, MSG_OK);                               \
+  osalSysUnlockFromISR();                                                   \
+}
+
+/**
+ * @brief   Common ISR code.
+ * @details This code handles the portable part of the ISR code:
+ *          - Callback invocation.
+ *          - Waiting thread wakeup, if any.
+ *          - Driver state transitions.
+ *          .
+ * @note    This macro is meant to be used in the low level drivers
+ *          implementation only.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @notapi
+ */
+#define _rng_isr_code(rngp, rng) {                                          \
+  if ((rngp)->config->end_cb) {                                             \
+    (rngp)->state = RNG_COMPLETE;                                           \
+    (rngp)->config->end_cb(rngp, rng);                                      \
+    if ((rngp)->state == RNG_COMPLETE)                                      \
+      (rngp)->state = RNG_READY;                                            \
+  }                                                                         \
+  else                                                                      \
+    (rngp)->state = RNG_READY;                                              \
+  _rng_wakeup_isr(rngp);                                                    \
+}
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void rngInit(void);
+  void rngObjectInit(RNGDriver *rngp);
+  void rngStart(RNGDriver *rngp, const RNGConfig *config);
+  void rngStop(RNGDriver *rngp);
+  msg_t rngWriteI(RNGDriver *rngp, uint8_t *buf, size_t n, systime_t timeout);
+  msg_t rngWrite(RNGDriver *rngp, uint8_t *buf, size_t n, systime_t timeout);
+#if RNG_USE_MUTUAL_EXCLUSION == TRUE
+  void rngAcquireUnit(RNGDriver *rngp);
+  void rngReleaseUnit(RNGDriver *rngp);
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* HAL_USE_RNG */
+
+#endif /* _RNG_H_ */
+
+/** @} */
diff --git a/os/hal/ports/NRF51/NRF51822/platform.mk b/os/hal/ports/NRF51/NRF51822/platform.mk
index 4fb50bc..96dd630 100644
--- a/os/hal/ports/NRF51/NRF51822/platform.mk
+++ b/os/hal/ports/NRF51/NRF51822/platform.mk
@@ -28,6 +28,9 @@ endif
 ifneq ($(findstring HAL_USE_GPT TRUE,$(HALCONF)),)
 PLATFORMSRC += ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/gpt_lld.c
 endif
+ifneq ($(findstring HAL_USE_RNG TRUE,$(HALCONF)),)
+PLATFORMSRC += ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/rng_lld.c
+endif
 else
 PLATFORMSRC  = ${CHIBIOS}/os/hal/ports/common/ARMCMx/nvic.c \
                ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/hal_lld.c \
@@ -39,7 +42,8 @@ PLATFORMSRC  = ${CHIBIOS}/os/hal/ports/common/ARMCMx/nvic.c \
                ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/ext_lld.c \
                ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/i2c_lld.c \
                ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/adc_lld.c \
-               ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/gpt_lld.c
+               ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/gpt_lld.c \
+               ${CHIBIOS_CONTRIB}/os/hal/ports/NRF51/NRF51822/rng_lld.c
 endif
 
 # Required include directories
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 */
+
+/** @} */
diff --git a/os/hal/ports/NRF51/NRF51822/rng_lld.h b/os/hal/ports/NRF51/NRF51822/rng_lld.h
new file mode 100644
index 0000000..a586ad4
--- /dev/null
+++ b/os/hal/ports/NRF51/NRF51822/rng_lld.h
@@ -0,0 +1,178 @@
+/*
+    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/NRF51822/rng_lld.h
+ * @brief   NRF51 RNG subsystem low level driver header.
+ *
+ * @addtogroup RNG
+ * @{
+ */
+
+#ifndef _RNG_LLD_H_
+#define _RNG_LLD_H_
+
+#if (HAL_USE_RNG == TRUE) || defined(__DOXYGEN__)
+
+/*
+ * This error check must occur outsite of RNGSW_USE_RNG1 to check if
+ * two LLD drivers are enabled at the same time
+ */
+#if (NRF51_RNG_USE_RNG1 == TRUE) && (RNGSW_USE_RNG1 == TRUE)
+#error "Software RNG can't be enable with NRF51_RNG_USE_RNG1"
+#endif
+
+/**
+ * Allow RNG Software override.
+ */
+#if RNGSW_USE_RNG1 != TRUE
+
+/*===========================================================================*/
+/* Driver constants.                                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/**
+ * @name    Configuration options
+ * @{
+ */
+/**
+ * @brief   RNG1 driver enable switch.
+ * @details If set to @p TRUE the support for RNG1 is included.
+ * @note    The default is @p FALSE.
+ */
+#if !defined(NRF51_RNG_USE_RNG1) || defined(__DOXYGEN__)
+#define NRF51_RNG_USE_RNG1                  FALSE
+#endif
+
+/**
+ * @brief   RNG1 driver enable switch.
+ * @details If set to @p TRUE the support for RNG1 is included.
+ * @note    The default is @p FALSE.
+ */
+#if !defined(NRF51_RNG_USE_RNG1) || defined(__DOXYGEN__)
+#define NRF51_RNG_USE_POWER_ON_WRITE        FALSE
+#endif
+
+/**
+ * @brief   RNG1 interrupt priority level setting.
+ */
+#if !defined(NRF51_RNG_RNG1_IRQ_PRIORITY) || defined(__DOXYGEN__)
+#define NRF51_RNG_RNG1_IRQ_PRIORITY     8
+#endif
+
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+
+/*===========================================================================*/
+/* Driver data structures and types.                                         */
+/*===========================================================================*/
+
+/**
+ * @brief   Type of a structure representing an RNG driver.
+ */
+typedef struct RNGDriver RNGDriver;
+
+/**
+ * @brief   Driver configuration structure.
+ */
+typedef struct {
+  /* End of the mandatory fields.*/
+  /**
+   * @brief   Activate the digital error correction
+   *
+   * @details A digital corrector algorithm is employed to remove any
+   *          bias toward '1' or '0'. Disabling it offers a substantial
+   *          speed advantage, but may result in a statistical distribution
+   *          that is not perfectly uniform.
+   *
+   * @note    On average, it take 167µs to get a byte without digitial
+   *          error correction and 677µs with, but no garantee is made
+   *          on the necessary time to generate one byte.
+   */
+  uint8_t digital_error_correction:1;
+  /**
+   * @brief   Only power the RNG device when requeting random bytes
+   *
+   * @details Device will not be powered when started/stopped 
+   *          but only when writint bytes.
+   */
+  uint8_t power_on_write:1;
+} RNGConfig;
+
+
+/**
+ * @brief   Structure representing an RNG driver.
+ */
+struct RNGDriver {
+  /**
+   * @brief Driver state.
+   */
+  rngstate_t                state;
+  /**
+   * @brief Current configuration data.
+   */
+  const RNGConfig           *config;
+#if RNG_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
+  /**
+   * @brief   Mutex protecting the peripheral.
+   */
+  mutex_t                   mutex;
+#endif /* RNG_USE_MUTUAL_EXCLUSION */
+  /* End of the mandatory fields.*/
+  /**
+   * @brief Pointer to the RNGx registers block.
+   */
+  NRF_RNG_Type             *rng;
+};
+
+/*===========================================================================*/
+/* Driver macros.                                                            */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#if NRF51_RNG_USE_RNG1 && !defined(__DOXYGEN__)
+extern RNGDriver RNGD1;
+#endif /* NRF51_RNG_USE_RNG1 */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void rng_lld_init(void);
+  void rng_lld_start(RNGDriver *rngp);
+  void rng_lld_stop(RNGDriver *rngp);
+  msg_t rng_lld_write(RNGDriver *rngp, uint8_t *buf, size_t n,
+		      systime_t timeout);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* RNGSW_USE_RNG1 */
+
+#endif /* HAL_USE_RNG */
+
+#endif /* _RNG_LLD_H_ */
+
+/** @} */
diff --git a/os/hal/src/hal_community.c b/os/hal/src/hal_community.c
index a24d26e..210df69 100644
--- a/os/hal/src/hal_community.c
+++ b/os/hal/src/hal_community.c
@@ -64,6 +64,10 @@ void halCommunityInit(void) {
 #if HAL_USE_CRC || defined(__DOXYGEN__)

   crcInit();

 #endif

+

+#if HAL_USE_RNG || defined(__DOXYGEN__)

+  rngInit();

+#endif

 }

 

 #endif /* HAL_USE_COMMUNITY */

diff --git a/os/hal/src/rng.c b/os/hal/src/rng.c
new file mode 100644
index 0000000..f9c3811
--- /dev/null
+++ b/os/hal/src/rng.c
@@ -0,0 +1,185 @@
+/*
+    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.
+*/
+
+/*
+ * Hardware Abstraction Layer for RNG Unit
+ */
+#include "hal.h"
+
+#if (HAL_USE_RNG == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local variables and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   RNG Driver initialization.
+ *
+ * @init
+ */
+void rngInit(void) {
+  rng_lld_init();
+}
+
+/**
+ * @brief   Initializes the standard part of a @p RNGDriver structure.
+ *
+ * @param[out] rngp    Pointer to the @p RNGDriver object
+ *
+ * @init
+ */
+void rngObjectInit(RNGDriver *rngp) {
+  rngp->state  = RNG_STOP;
+  rngp->config = NULL;
+#if RNG_USE_MUTUAL_EXCLUSION == TRUE
+  osalMutexObjectInit(&rngp->mutex);
+#endif
+#if defined(RNG_DRIVER_EXT_INIT_HOOK)
+  RNG_DRIVER_EXT_INIT_HOOK(rngp);
+#endif
+}
+
+/**
+ * @brief   Configures and activates the RNG peripheral.
+ *
+ * @param[in] rngp      Pointer to the @p RNGDriver object
+ * @param[in] config    Pointer to the @p RNGConfig object
+ *                      @p NULL if the low level driver implementation
+ *                      supports a default configuration
+ *
+ * @api
+ */
+void rngStart(RNGDriver *rngp, const RNGConfig *config) {
+  osalDbgCheck(rngp != NULL);
+
+  osalSysLock();
+  osalDbgAssert((rngp->state == RNG_STOP) || (rngp->state == RNG_READY),
+                "invalid state");
+  rngp->config = config;
+  rng_lld_start(rngp);
+  rngp->state = RNG_READY;
+  osalSysUnlock();
+}
+
+/**
+ * @brief   Deactivates the RNG peripheral.
+ *
+ * @param[in] rngp     Pointer to the @p RNGDriver object
+ *
+ * @api
+ */
+void rngStop(RNGDriver *rngp) {
+  osalDbgCheck(rngp != NULL);
+
+  osalSysLock();
+  osalDbgAssert((rngp->state == RNG_STOP) || (rngp->state == RNG_READY),
+                "invalid state");
+  rng_lld_stop(rngp);
+  rngp->state = RNG_STOP;
+  osalSysUnlock();
+}
+
+/**
+ * @brief   Performs a RNG calculation.
+ * @details This synchronous function performs a rng calculation operation.
+ * @pre     In order to use this function the driver must have been configured
+ *          without callbacks (@p end_cb = @p NULL).
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ * @param[in] n         number of bytes to send
+ * @param[in] buf       the pointer to the buffer
+ *
+ * @api
+ */
+msg_t rngWrite(RNGDriver *rngp, uint8_t *buf, size_t n, systime_t timeout) {
+  msg_t msg;
+  osalSysLock();
+  msg = rngWriteI(rngp, buf, n, timeout);
+  osalSysUnlock();
+  return msg;
+}
+
+/**
+ * @brief   Performs a RNG calculation.
+ * @details This synchronous function performs a rng calcuation operation.
+ * @pre     In order to use this function the driver must have been configured
+ *          without callbacks (@p end_cb = @p NULL).
+ * @post    At the end of the operation the configured callback is invoked.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ * @param[in] n         number of bytes to send
+ * @param[in] buf       the pointer to the buffer
+ *
+ * @iclass
+ */
+msg_t rngWriteI(RNGDriver *rngp, uint8_t *buf, size_t n, systime_t timeout) {
+  osalDbgCheck((rngp != NULL) && (n > 0U) && (buf != NULL));
+  osalDbgAssert(rngp->state == RNG_READY, "not ready");
+  return rng_lld_write(rngp, buf, n, timeout);
+}
+
+
+#if (RNG_USE_MUTUAL_EXCLUSION == TRUE) || defined(__DOXYGEN__)
+/**
+ * @brief   Gains exclusive access to the RNG unit.
+ * @details This function tries to gain ownership to the RNG, if the RNG is
+ *          already being used then the invoking thread is queued.
+ * @pre     In order to use this function the option @p RNG_USE_MUTUAL_EXCLUSION
+ *          must be enabled.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @api
+ */
+void rngAcquireUnit(RNGDriver *rngp) {
+  osalDbgCheck(rngp != NULL);
+
+  osalMutexLock(&rngp->mutex);
+}
+
+/**
+ * @brief   Releases exclusive access to the RNG unit.
+ * @pre     In order to use this function the option @p RNG_USE_MUTUAL_EXCLUSION
+ *          must be enabled.
+ *
+ * @param[in] rngp      pointer to the @p RNGDriver object
+ *
+ * @api
+ */
+void rngReleaseUnit(RNGDriver *rngp) {
+  osalDbgCheck(rngp != NULL);
+
+  osalMutexUnlock(&rngp->mutex);
+}
+#endif /* RNG_USE_MUTUAL_EXCLUSION == TRUE */
+
+#endif /* HAL_USE_RNG */