/* * Copyright (c) 2017 Nordic Semiconductor ASA * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this list * of conditions and the following disclaimer. * * 2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA * integrated circuit in a product or a software update for such product, must reproduce * the above copyright notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the distribution. * * 3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be * used to endorse or promote products derived from this software without specific prior * written permission. * * 4. This software, with or without modification, must only be used with a * Nordic Semiconductor ASA integrated circuit. * * 5. Any software provided in binary or object form under this license must not be reverse * engineered, decompiled, modified and/or disassembled. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #if DEVICE_TRNG #if !defined(FEATURE_CRYPTOCELL310) #include "hal/trng_api.h" #include "hal/critical_section_api.h" #include "nrf_drv_rng.h" /* Keep track of instantiated FlashIAP objects. */ static int nordic_trng_counter = 0; void trng_init(trng_t *obj) { MBED_ASSERT(obj); /* Increment global counter. */ nordic_trng_counter++; /* Initialize TRNG on first object only. */ if (nordic_trng_counter == 1) { nrf_drv_rng_init(NULL); } } void trng_free(trng_t *obj) { MBED_ASSERT(obj); /* Decrement global counter. */ nordic_trng_counter--; /* Deinitialize TRNG when all objects have been freed. */ if (nordic_trng_counter == 0) { nrf_drv_rng_uninit(); } } /* Get random data from NRF5x TRNG peripheral. * * This implementation returns num of random bytes in range <1, length>. * For parameters description see trng_api.h file. */ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length) { MBED_ASSERT(obj); MBED_ASSERT(output); MBED_ASSERT(output_length); int result = 0; /* Return immediately if requested length is zero. */ if (length != 0) { /* Query how many bytes are available. */ uint8_t bytes_available; nrf_drv_rng_bytes_available(&bytes_available); /* If no bytes are cached, block until at least 1 byte is available. */ if (bytes_available == 0) { nrf_drv_rng_block_rand(output, 1); *output_length = 1; } else { /* Get up to the requested number of bytes. */ if (bytes_available > length) { bytes_available = length; } ret_code_t result = nrf_drv_rng_rand(output, bytes_available); /* Set output length with available bytes. */ if (result == NRF_SUCCESS) { *output_length = bytes_available; } else { *output_length = 0; } } /* Set return value based on how many bytes were read. */ result = (*output_length == 0) ? -1 : 0; } return result; } #endif/* !FEATURE_CRYPTOCELL310 */ #endif