nrf: Remove custom "random" module and use extmod version instead.

Hardware RNG code is moved to drivers/rng.[ch].

Author: dpgeorge

ports/nrf/Makefile

@@ -56,7 +56,6 @@ INC += -I./../../lib/cmsis/inc
 INC += -I./modules/machine
 INC += -I./modules/ubluepy
 INC += -I./modules/music
-INC += -I./modules/random
 INC += -I./modules/ble
 INC += -I./modules/board
 INC += -I../../lib/mp-readline
@@ -230,6 +229,7 @@ SRC_C += \
 	pin_named_pins.c \
 	fatfs_port.c \
 	drivers/flash.c \
+	drivers/rng.c \
 	drivers/softpwm.c \
 	drivers/ticker.c \
 	drivers/bluetooth/ble_drv.c \
@@ -292,7 +292,6 @@ DRIVERS_SRC_C += $(addprefix modules/,\
 	music/modmusic.c \
 	music/musictunes.c \
 	ble/modble.c \
-	random/modrandom.c \
 	)
 
 # Custom micropython startup file with smaller interrupt vector table

ports/nrf/drivers/rng.c

@@ -0,0 +1,79 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 Glenn Ruben Bakke
+ * Copyright (c) 2018 Ayke van Laethem
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/mpconfig.h"
+
+#if MICROPY_PY_RANDOM_HW_RNG
+
+#include "nrf_rng.h"
+#include "drivers/rng.h"
+
+#if BLUETOOTH_SD
+#include "nrf_soc.h"
+#include "ble_drv.h"
+#define BLUETOOTH_STACK_ENABLED() (ble_drv_stack_enabled())
+#endif
+
+static inline uint32_t generate_hw_random(void) {
+    uint32_t retval = 0;
+    uint8_t * p_retval = (uint8_t *)&retval;
+
+    nrf_rng_event_clear(NRF_RNG_EVENT_VALRDY);
+    nrf_rng_task_trigger(NRF_RNG_TASK_START);
+
+    for (uint16_t i = 0; i < 4; i++) {
+        while (!nrf_rng_event_get(NRF_RNG_EVENT_VALRDY)) {
+            ;
+        }
+
+        nrf_rng_event_clear(NRF_RNG_EVENT_VALRDY);
+        p_retval[i] = nrf_rng_random_value_get();
+    }
+
+    nrf_rng_task_trigger(NRF_RNG_TASK_STOP);
+
+    return retval;
+}
+
+uint32_t rng_generate_random_word(void) {
+
+#if BLUETOOTH_SD
+    if (BLUETOOTH_STACK_ENABLED() == 1) {
+        uint32_t retval = 0;
+        uint32_t status;
+        do {
+            status = sd_rand_application_vector_get((uint8_t *)&retval, 4); // Extract 4 bytes
+        } while (status != 0);
+
+        return retval;
+    }
+#endif
+
+    return generate_hw_random();
+}
+
+#endif // MICROPY_PY_RANDOM_HW_RNG

ports/nrf/modules/random/modrandom.h ports/nrf/drivers/rng.h

@@ -24,4 +24,4 @@
  * THE SOFTWARE.
  */
 
-uint32_t machine_rng_generate_random_word(void);
+uint32_t rng_generate_random_word(void);

ports/nrf/modules/random/modrandom.c

@@ -31,7 +31,7 @@
 
 #include "microbitfs.h"
 #include "drivers/flash.h"
-#include "modrandom.h"
+#include "drivers/rng.h"
 #include "py/obj.h"
 #include "py/stream.h"
 #include "py/runtime.h"
@@ -175,7 +175,7 @@ STATIC void init_limits(void) {
 }
 
 STATIC void randomise_start_index(void) {
-    start_index = machine_rng_generate_random_word() % chunks_in_file_system + 1;
+    start_index = rng_generate_random_word() % chunks_in_file_system + 1;
 }
 
 void microbit_filesystem_init(void) {

ports/nrf/modules/uos/microbitfs.c

@@ -42,7 +42,7 @@
 //#include "portmodules.h"
 
 #if MICROPY_HW_ENABLE_RNG
-#include "modrandom.h"
+#include "drivers/rng.h"
 #endif // MICROPY_HW_ENABLE_RNG
 
 /// \module os - basic "operating system" services
@@ -105,7 +105,7 @@ STATIC mp_obj_t os_urandom(mp_obj_t num) {
     vstr_t vstr;
     vstr_init_len(&vstr, n);
     for (int i = 0; i < n; i++) {
-        vstr.buf[i] = (uint8_t)(machine_rng_generate_random_word() & 0xFF);
+        vstr.buf[i] = (uint8_t)(rng_generate_random_word() & 0xFF);
     }
     return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
 }