Import Mbed OS hard-float snapshot

targets/TARGET_GigaDevice/TARGET_GD32F4XX/trng_api.c

@@ -0,0 +1,87 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2018 GigaDevice Semiconductor Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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.
+ */
+#if DEVICE_TRNG
+
+#include "trng_api.h"
+
+/** Initialize the TRNG peripheral
+ *
+ * @param obj The TRNG object
+ */
+void trng_init(trng_t *obj)
+{
+    (void)obj;
+    /* TRNG module clock enable */
+    rcu_periph_clock_enable(RCU_TRNG);
+
+    /* TRNG registers reset */
+    trng_deinit();
+    trng_enable();
+}
+
+/** Deinitialize the TRNG peripheral
+ *
+ * @param obj The TRNG object
+ */
+void trng_free(trng_t *obj)
+{
+    (void)obj;
+    trng_disable();
+}
+
+/** Get random data from TRNG peripheral
+ *
+ * @param obj The TRNG object
+ * @param output The pointer to an output array
+ * @param length The size of output data, to avoid buffer overwrite
+ * @param output_length The length of generated data
+ * @return 0 success, -1 fail
+ */
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    int reval = 0;
+    volatile uint8_t tmp[4];
+    uint32_t timeout = 0;
+
+    (void)obj;
+    *output_length = 0;
+
+    while ((*output_length < length) && (0 == reval)) {
+        while (0 == trng_flag_get(TRNG_FLAG_DRDY) && timeout < 0x1FFFF) {
+            timeout++;
+        }
+        if (timeout == 0x1FFFF) {
+            reval = -1;
+            break;
+        }
+        *(uint32_t *)tmp = trng_get_true_random_data();
+        for (uint8_t i = 0; (i < 4) && (*output_length < length) ; i++) {
+            *output++ = tmp[i];
+            *output_length += 1;
+            tmp[i] = 0;
+        }
+    }
+
+    /* Determines the status error current and error current */
+    if ((1 == trng_flag_get(TRNG_FLAG_CECS)) || (1 == trng_flag_get(TRNG_FLAG_SECS))) {
+        reval = -1;
+    }
+
+    return reval;
+}
+#endif /* DEVICE_TRNG */