periph: added a random-data driver interface

drivers/include/periph/random.h

@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup     driver_periph
+ * @{
+ *
+ * @file
+ * @brief       (Pseudo) random number generator low-level driver interface
+ *
+ * NOTE: The quality of the random data read from this interface is highly
+ * dependent on hardware dependent implementation. Most platforms utilize a
+ * hardware (Pseudo) Random Number Generator. The quality of the generated
+ * random data can be however very different.
+ *
+ * @note REFER TO YOUR PLATFORMS IMPLEMENTATION ABOUT INFORMATION ABOUT THE
+ *       QUALITY OF RANDOMNES!
+ *
+ * @author      Christian Mehlis <mehlis@inf.fu-berlin.de>
+ */
+
+#ifndef __RANDOM_H
+#define __RANDOM_H
+
+#include "periph_conf.h"
+
+/* only include this file if a random number generator is defined */
+#if RANDOM_NUMOF
+
+/**
+ * @brief Initializes the source of randomness
+ *
+ * In case of a hardware random number generator, this peripheral
+ * is initialized and powered on. If such a device is not present,
+ * it depends on the implementation how a source for randomness
+ * is created and initialized.
+ */
+void random_init(void);
+
+/**
+ * @brief Reads num or less bytes of randomness from the source, will
+ *        block until random data is available
+ *
+ * @param[in] buf   destination buffer to write the bytes to
+ * @param[in] num   number of bytes to get from device,
+ *                  only values >0 are valid
+ *
+ * @return          the number of bytes written to buf
+ * @return          0 on error
+ */
+int random_read(char *buf, unsigned int num);
+
+/**
+ * @brief Power on the random number generator
+ */
+void random_poweron(void);
+
+/**
+ * @brief Power off the random number generator
+ */
+void random_poweroff(void);
+
+#endif /* RANDOM_NUMOF */
+
+#endif /* __RANDOM_H */
+/** @} */