From 809fd8a17a0d19e1880d57e51d7a7d3092befccb Mon Sep 17 00:00:00 2001
From: Romain Goyet <romain.goyet@numworks.com>
Date: Thu, 16 Feb 2017 11:36:29 +0100
Subject: [PATCH] [ion] Ion::random()

Change-Id: Ib85055ab3b4bf3dfce991f9990659c744be20f39
---
 ion/include/ion.h          |  3 +++
 ion/src/device/device.cpp  | 16 ++++++++++++++++
 ion/src/shared/random.cpp  |  6 ++++++
 ion/src/simulator/Makefile |  1 +
 4 files changed, 26 insertions(+)
 create mode 100644 ion/src/shared/random.cpp

diff --git a/ion/include/ion.h b/ion/include/ion.h
index 3c7b281ad..5ae753fb6 100644
--- a/ion/include/ion.h
+++ b/ion/include/ion.h
@@ -33,6 +33,9 @@ void reset();
 // Only accepts whole 32bit values
 uint32_t crc32(const uint32_t * data, size_t length);
 
+// Provides a true random number
+uint32_t random();
+
 }
 
 #endif
diff --git a/ion/src/device/device.cpp b/ion/src/device/device.cpp
index cd302e99c..c87a2c142 100644
--- a/ion/src/device/device.cpp
+++ b/ion/src/device/device.cpp
@@ -41,6 +41,22 @@ uint32_t Ion::crc32(const uint32_t * data, size_t length) {
   return result;
 }
 
+uint32_t Ion::random() {
+  bool initialRNGEngineState = RCC.AHB2ENR()->getRNGEN();
+  RCC.AHB2ENR()->setRNGEN(true);
+
+  RNG.CR()->setRNGEN(true);
+
+  while (RNG.SR()->getDRDY() == 0) {
+  }
+  uint32_t result = RNG.DR()->get();
+
+  RNG.CR()->setRNGEN(false);
+  RCC.AHB2ENR()->setRNGEN(initialRNGEngineState);
+
+  return result;
+}
+
 void Ion::reset() {
   CM4.AIRCR()->requestReset();
 }
diff --git a/ion/src/shared/random.cpp b/ion/src/shared/random.cpp
new file mode 100644
index 000000000..9ec8feb00
--- /dev/null
+++ b/ion/src/shared/random.cpp
@@ -0,0 +1,6 @@
+#include <ion.h>
+#include <stdlib.h>
+
+uint32_t Ion::random() {
+  return rand();
+}
diff --git a/ion/src/simulator/Makefile b/ion/src/simulator/Makefile
index 19466fbe0..cfaf469ad 100644
--- a/ion/src/simulator/Makefile
+++ b/ion/src/simulator/Makefile
@@ -12,6 +12,7 @@ objs += $(addprefix ion/src/shared/, \
   events_keyboard.o \
   log_printf.o \
   power.o \
+  random.o \
 )
 
 SFLAGS += `fltk-config --cflags`