FASTMODEL: add simulated TRNG implementation to fastmodel

Author: Qinghao Shi

targets/TARGET_ARM_FM/TARGET_FVP_MPS2/objects.h

@@ -78,6 +78,10 @@ struct flash_s {
     uint8_t not_used;
 };
 
+struct trng_s {
+    uint8_t not_used;
+};
+
 #include "gpio_object.h"
 
 #ifdef __cplusplus

targets/TARGET_ARM_FM/TARGET_FVP_MPS2/trng_api.c

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2017-2019 ARM Limited
+ * 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.
+ */
+
+#include "trng_api.h"
+#include "device.h"
+#include <stdlib.h>
+
+
+
+void trng_init(trng_t *obj)
+{
+    srand(0);
+    (void)obj;
+}
+
+
+void trng_free(trng_t *obj)
+{
+    (void)obj;
+}
+
+/** 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)
+{
+    (void)obj;
+    (void)output;
+
+    for (int i = 0; i < length; ++i) {
+        output[i] = rand() % 256;
+    }
+    *output_length = length;
+
+    return 0;
+
+}