Diff: targets/TARGET_Cypress/TARGET_PSOC6/trng_api.c

Revision:

189:f392fc9709a3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Cypress/TARGET_PSOC6/trng_api.c	Wed Feb 20 22:31:08 2019 +0000
@@ -0,0 +1,73 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 Cypress Semiconductor Corporation
+ * 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.
+ */
+
+/*  Hardware entropy collector for the PSoC6A families */
+
+#if DEVICE_TRNG
+
+#include "trng_api.h"
+#include "psoc6_utils.h"
+#include "cy_crypto_core_trng.h"
+
+/* Initialization polynomial values fro True Random Generator */
+#define GARO31_INITSTATE          (0x04c11db7u)
+#define FIRO31_INITSTATE          (0x04c11db7u)
+
+#define MAX_TRNG_BIT_SIZE         (32UL)
+
+void trng_init(trng_t *obj)
+{
+    (void)obj;
+
+    cy_reserve_crypto(CY_CRYPTO_TRNG_HW);
+}
+
+void trng_free(trng_t *obj)
+{
+    /* Deinitialization is not needed for the driver */
+    (void)obj;
+
+    cy_free_crypto(CY_CRYPTO_TRNG_HW);
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    int ret = 0;
+    *output_length = 0;
+
+    /* temporary random data buffer */
+    uint32_t random;
+
+    (void)obj;
+
+    /* Get Random byte */
+    while ((*output_length < length) && (ret == 0)) {
+        if (Cy_Crypto_Core_Trng(CRYPTO, GARO31_INITSTATE, FIRO31_INITSTATE, MAX_TRNG_BIT_SIZE, &random) != CY_CRYPTO_SUCCESS) {
+            ret = -1;
+        } else {
+            for (uint8_t i = 0; (i < 4) && (*output_length < length) ; i++) {
+                *output++ = ((uint8_t *)&random)[i];
+                *output_length += 1;
+            }
+        }
+    }
+    random = 0uL;
+
+    return (ret);
+}
+
+#endif