Import Mbed OS hard-float snapshot

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/trng_api.c

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2017 Nordic Semiconductor ASA
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list
+ *      of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA
+ *      integrated circuit in a product or a software update for such product, must reproduce
+ *      the above copyright notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the distribution.
+ *
+ *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be
+ *      used to endorse or promote products derived from this software without specific prior
+ *      written permission.
+ *
+ *   4. This software, with or without modification, must only be used with a
+ *      Nordic Semiconductor ASA integrated circuit.
+ *
+ *   5. Any software provided in binary or object form under this license must not be reverse
+ *      engineered, decompiled, modified and/or disassembled.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#if DEVICE_TRNG
+#if !defined(FEATURE_CRYPTOCELL310)
+#include "hal/trng_api.h"
+#include "hal/critical_section_api.h"
+
+#include "nrf_drv_rng.h"
+
+/* Keep track of instantiated FlashIAP objects. */
+static int nordic_trng_counter = 0;
+
+void trng_init(trng_t *obj)
+{
+    MBED_ASSERT(obj);
+
+    /* Increment global counter. */
+    nordic_trng_counter++;
+
+    /* Initialize TRNG on first object only. */
+    if (nordic_trng_counter == 1) {
+        nrf_drv_rng_init(NULL);
+    }
+}
+
+void trng_free(trng_t *obj)
+{
+    MBED_ASSERT(obj);
+
+    /* Decrement global counter. */
+    nordic_trng_counter--;
+
+    /* Deinitialize TRNG when all objects have been freed. */
+    if (nordic_trng_counter == 0) {
+        nrf_drv_rng_uninit();
+    }
+}
+
+/* Get random data from NRF5x TRNG peripheral.
+ *
+ * This implementation returns num of random bytes in range <1, length>.
+ * For parameters description see trng_api.h file.
+ */
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    MBED_ASSERT(obj);
+    MBED_ASSERT(output);
+    MBED_ASSERT(output_length);
+
+    int result = 0;
+
+    /* Return immediately if requested length is zero. */
+    if (length != 0) {
+
+        /* Query how many bytes are available. */
+        uint8_t bytes_available;
+        nrf_drv_rng_bytes_available(&bytes_available);
+
+        /* If no bytes are cached, block until at least 1 byte is available. */
+        if (bytes_available == 0) {
+            nrf_drv_rng_block_rand(output, 1);
+            *output_length = 1;
+        } else {
+
+            /* Get up to the requested number of bytes. */
+            if (bytes_available > length) {
+                bytes_available = length;
+            }
+
+            ret_code_t result = nrf_drv_rng_rand(output, bytes_available);
+
+            /* Set output length with available bytes. */
+            if (result == NRF_SUCCESS) {
+                *output_length = bytes_available;
+            } else {
+                *output_length = 0;
+            }
+        }
+
+        /* Set return value based on how many bytes were read. */
+        result = (*output_length == 0) ? -1 : 0;
+    }
+
+    return result;
+}
+#endif/* !FEATURE_CRYPTOCELL310 */
+#endif