Added Random Number Generator for stm32 autopilots

conf/airframes/AGGIEAIR/aggieair_ark_hexa_1-8.xml

@@ -56,6 +56,7 @@ Aggie Air ARK
 
   <modules>
     <module name="sys_mon"/>
+    <module name="rng"/>
     <module name="copilot"/>
     <module name="extra_dl">
       <!-- in order to use uart1 without chibios we need to remap the peripheral-->

conf/airframes/examples/quadrotor_lisa_mx.xml

@@ -53,6 +53,7 @@
     <module name="gps" type="ubx_ucenter"/>
     <module name="geo_mag"/>
     <module name="air_data"/>
+    <module name="rng"/>
   </modules>
 
   <servos driver="Pwm">

conf/modules/rng.xml

@@ -0,0 +1,17 @@
+<!DOCTYPE module SYSTEM "module.dtd">
+
+<module name="rng" dir="mcu_periph" task="mcu">
+  <doc>
+    <description>
+      Random Number Generator
+    </description>
+  </doc>
+  <header>
+    <file name="rng.h" dir="mcu_periph"/>
+  </header>
+  <makefile>
+    <define name="USE_RNG"/>
+    <file_arch name="rng_arch.c" dir="mcu_periph"/>
+  </makefile>
+</module>
+

sw/airborne/arch/stm32/mcu_periph/rng_arch.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2017 Michal Podhradsky <mpodhradsky@galois.com>
+ *
+ * This file is part of Paparazzi.
+ *
+ * Paparazzi 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 2, or (at your option)
+ * any later version.
+ *
+ * Paparazzi 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 Paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+/** \file rng_arch.c
+ *  \brief arch specific Random Number Generator API
+ *
+ */
+#include "mcu_periph/rng.h"
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/rng.h>
+
+uint32_t last;
+
+void rng_init(void) {
+  rcc_periph_clock_enable(RCC_RNG);
+  rng_enable();
+  // dont forget to throw away the first generated number
+  last = rng_wait_and_get();
+}
+
+void rng_deinit(void) {
+  rng_disable();
+  rcc_periph_clock_disable(RCC_RNG);
+}
+
+// Return true only if we got a new number
+// that is different from the previous one
+bool rng_get(uint32_t *rand_nr) {
+  uint32_t tmp = 0;
+  if (rng_get_random(&tmp) && (tmp != last)) {
+    last = tmp;
+    *rand_nr = tmp;
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// Wait until we get a new number that is different
+// from the previous one. We can wait forever here if
+// the clocks are not setup properly.
+uint32_t rng_wait_and_get(void) {
+  uint32_t tmp = last;
+  while (tmp == last) {
+    tmp = rng_get_random_blocking();
+  }
+  last = tmp;
+  return tmp;
+}

sw/airborne/mcu.c

@@ -61,6 +61,9 @@
 #ifdef USE_DAC
 #include "mcu_periph/dac.h"
 #endif
+#ifdef USE_RNG
+#include "mcu_periph/rng.h"
+#endif
 #endif /* PERIPHERALS_AUTO_INIT */
 
 void WEAK board_init(void)
@@ -219,6 +222,10 @@ void mcu_init(void)
   udp_arch_init();
 #endif
 
+#ifdef USE_RNG
+  rng_init();
+#endif
+
 #else
   INFO("PERIPHERALS_AUTO_INIT not enabled! Peripherals (including sys_time) need explicit initialization.")
 #endif /* PERIPHERALS_AUTO_INIT */

sw/airborne/mcu_periph/rng.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2017 Michal Podhradsky <mpodhradsky@galois.com>
+ *
+ * This file is part of Paparazzi.
+ *
+ * Paparazzi 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 2, or (at your option)
+ * any later version.
+ *
+ * Paparazzi 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 Paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+/** \file rng.h
+ *  \brief arch independent Random Number Generator API
+ *
+ */
+
+#ifndef MCU_PERIPH_RNG_H
+#define MCU_PERIPH_RNG_H
+
+#include <inttypes.h>
+#include "std.h"
+
+void rng_init(void);
+void rng_deinit(void);
+bool rng_get(uint32_t *rand_nr);
+uint32_t rng_wait_and_get(void);
+
+#endif /* MCU_PERIPH_RNG_H */