rp2/mbedtls: Add support for ssl module with MICROPY_SSL_MBEDTLS.

Signed-off-by: Andrew Leech <andrew@alelec.net>

ports/rp2/mbedtls/mbedtls_port.c

@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <py/mpconfig.h>
+
+#ifdef MICROPY_SSL_MBEDTLS
+
+#include "mbedtls_config.h"
+
+extern uint8_t rosc_random_u8(size_t cycles);
+
+int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len, size_t *olen) {
+    *olen = len;
+    for (size_t i = 0; i < len; i++) {
+        output[i] = rosc_random_u8(8);
+    }
+    return 0;
+}
+
+#endif