Support TRNG function for GR-LYCHEE

I supported the TRNG function when target is GR-LYCHEE.
GR-LYCHEE generates TRNG by acquiring the random number of Wifi module(ESP32) incorporated in it using I2C.

targets/TARGET_RENESAS/TARGET_RZ_A1XX/TARGET_GR_LYCHEE/trng_api_esp32.cpp

@@ -0,0 +1,86 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2017 ARM Limited
+ *
+ * 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 defined(DEVICE_TRNG)
+#include "drivers/I2C.h"
+#include "platform/mbed_wait_api.h"
+
+#define ESP32_I2C_ADDR    (0x28<<1)
+
+extern "C" void trng_init_esp32(void)
+{
+    /* P5_3(EN), P3_14(IO0) */
+    if (((GPIOP5   & 0x0008) == 0)
+     || ((GPIOPMC5 & 0x0008) != 0)
+     || ((GPIOPM5  & 0x0008) != 0)
+     || ((GPIOP3   & 0x4000) == 0)
+     || ((GPIOPMC3 & 0x4000) != 0)
+     || ((GPIOPM3  & 0x4000) != 0)) {
+
+        /* P5_3(EN) */
+        GPIOP5   &= ~0x0008;         /* Outputs low level */
+        GPIOPMC5 &= ~0x0008;         /* Port mode */
+        GPIOPM5  &= ~0x0008;         /* Output mode */
+
+        /* P3_14(IO0) */
+        GPIOP3   &= ~0x4000;         /* Outputs low level */
+        GPIOPMC3 &= ~0x4000;         /* Port mode */
+        GPIOPM3  &= ~0x4000;         /* Output mode */
+
+        GPIOP3   |=  0x4000;         /* Outputs hi level */
+        wait_ms(5);
+        GPIOP5   |=  0x0008;         /* Outputs hi level */
+    }
+}
+
+extern "C" void trng_free_esp32(void)
+{
+    // do nothing
+}
+
+extern "C" int trng_get_bytes_esp32(uint8_t *output, size_t length, size_t *output_length)
+{
+    mbed::I2C mI2c(I2C_SDA, I2C_SCL);
+    int ret;
+    char send_data[1];
+    char recv_data[4];
+    size_t idx = 0;
+    int i;
+    int err_cnt = 0;
+
+    while (idx < length) {
+        send_data[0] = 0;
+        ret = mI2c.write(ESP32_I2C_ADDR, send_data, 1);
+        if (ret == 0) {
+            mI2c.read(ESP32_I2C_ADDR, recv_data, sizeof(recv_data));
+            for (i = 0; (i < 4) && (idx < length); i++) {
+                output[idx++] = recv_data[i];
+            }
+        } else {
+            err_cnt++;
+            if (err_cnt >= 20) {
+                break;
+            }
+            wait_ms(100);
+        }
+    }
+    if (output_length != NULL) {
+        *output_length = idx;
+    }
+
+    return (idx != 0 ? 0 : -1);
+}
+#endif

targets/TARGET_RENESAS/TARGET_RZ_A1XX/objects.h

@@ -77,6 +77,10 @@ struct can_s {
     uint32_t ch;
 };
 
+struct trng_s {
+    uint8_t dummy;
+};
+
 #ifdef __cplusplus
 }
 #endif

targets/TARGET_RENESAS/TARGET_RZ_A1XX/trng_api.c

@@ -0,0 +1,43 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2017 ARM Limited
+ *
+ * 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 defined(DEVICE_TRNG)
+#include "trng_api.h"
+
+#if defined(TARGET_GR_LYCHEE)
+
+extern void trng_init_esp32(void);
+extern void trng_free_esp32(void);
+extern int trng_get_bytes_esp32(uint8_t *output, size_t length, size_t *output_length);
+
+void trng_init(trng_t *obj)
+{
+    trng_init_esp32();
+}
+
+void trng_free(trng_t *obj)
+{
+    trng_free_esp32();
+}
+
+int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
+{
+    return trng_get_bytes_esp32(output, length, output_length);
+}
+#else
+#error "There is no initialization processing."
+#endif
+#endif

targets/targets.json

@@ -2535,6 +2535,7 @@
         "inherits": ["RZ_A1XX"],
         "supported_form_factors": ["ARDUINO"],
         "extra_labels_add": ["RZA1UL", "MBRZA1LU"],
+        "device_has_add": ["TRNG"],
         "device_has_remove": ["ETHERNET"],
         "features_remove": ["LWIP"],
         "release_versions": ["2", "5"]