| /* |
| * Copyright (c) 2017, The OpenThread Authors. |
| * 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 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 the copyright holder nor the |
| * names of its contributors may be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * 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. |
| */ |
| |
| #include <utils/code_utils.h> |
| |
| #include <driverlib/prcm.h> |
| #include <driverlib/trng.h> |
| |
| #include <openthread/platform/random.h> |
| |
| #include <mbedtls/entropy_poll.h> |
| |
| enum |
| { |
| CC2650_TRNG_MIN_SAMPLES_PER_CYCLE = (1 << 6), |
| CC2650_TRNG_MAX_SAMPLES_PER_CYCLE = (1 << 24), |
| CC2650_TRNG_CLOCKS_PER_SAMPLE = 0, |
| }; |
| |
| /** |
| * \note if more than 32 bits of entropy are needed, the TRNG core produces |
| * 64 bytes of random data, we just ignore the upper 32 bytes |
| */ |
| |
| /** |
| * Function documented in platform-cc2650.h |
| */ |
| void cc2650RandomInit(void) |
| { |
| PRCMPowerDomainOn(PRCM_DOMAIN_PERIPH); |
| |
| while (PRCMPowerDomainStatus(PRCM_DOMAIN_PERIPH) != PRCM_DOMAIN_POWER_ON) |
| ; |
| |
| PRCMPeripheralRunEnable(PRCM_PERIPH_TRNG); |
| PRCMPeripheralSleepEnable(PRCM_DOMAIN_PERIPH); |
| PRCMPeripheralDeepSleepEnable(PRCM_DOMAIN_PERIPH); |
| PRCMLoadSet(); |
| TRNGConfigure(CC2650_TRNG_MIN_SAMPLES_PER_CYCLE, CC2650_TRNG_MAX_SAMPLES_PER_CYCLE, CC2650_TRNG_CLOCKS_PER_SAMPLE); |
| TRNGEnable(); |
| } |
| |
| /** |
| * Function documented in platform/random.h |
| */ |
| uint32_t otPlatRandomGet(void) |
| { |
| while (!(TRNGStatusGet() & TRNG_NUMBER_READY)) |
| ; |
| |
| return TRNGNumberGet(TRNG_LOW_WORD); |
| } |
| |
| /** |
| * Fill an arbitrary area with random data |
| * |
| * @param [out] aOutput area to place the random data |
| * @param [in] aLen size of the area to place random data |
| * @param [out] oLen how much of the output was written to |
| * |
| * @return indication of error |
| * @retval 0 no error occured |
| */ |
| static int TRNGPoll(unsigned char *aOutput, size_t aLen) |
| { |
| size_t length = 0; |
| union |
| { |
| uint32_t u32[2]; |
| uint8_t u8[8]; |
| } buffer; |
| |
| while (length < aLen) |
| { |
| if (length % 8 == 0) |
| { |
| /* we've run to the end of the buffer */ |
| while (!(TRNGStatusGet() & TRNG_NUMBER_READY)) |
| ; |
| |
| /* |
| * don't use TRNGNumberGet here because it will tell the TRNG to |
| * refil the entropy pool, instad we do it ourself. |
| */ |
| buffer.u32[0] = HWREG(TRNG_BASE + TRNG_O_OUT0); |
| buffer.u32[1] = HWREG(TRNG_BASE + TRNG_O_OUT1); |
| HWREG(TRNG_BASE + TRNG_O_IRQFLAGCLR) = 0x1; |
| } |
| |
| aOutput[length] = buffer.u8[length % 8]; |
| |
| length++; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * Function documented in platform/random.h |
| */ |
| otError otPlatRandomGetTrue(uint8_t *aOutput, uint16_t aOutputLength) |
| { |
| otError error = OT_ERROR_NONE; |
| size_t length = aOutputLength; |
| |
| otEXPECT_ACTION(aOutput, error = OT_ERROR_INVALID_ARGS); |
| |
| otEXPECT_ACTION(TRNGPoll((unsigned char *)aOutput, length) != 0, error = OT_ERROR_FAILED); |
| |
| exit: |
| return error; |
| } |