| /****************************************************************************** |
| * Filename: trng.c |
| * Revised: 2015-02-10 22:32:28 +0100 (Tue, 10 Feb 2015) |
| * Revision: 42645 |
| * |
| * Description: Driver for the TRNG module |
| * |
| * Copyright (c) 2015 - 2016, Texas Instruments Incorporated |
| * 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 ORGANIZATION 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 <driverlib/trng.h> |
| |
| //***************************************************************************** |
| // |
| // Handle support for DriverLib in ROM: |
| // This section will undo prototype renaming made in the header file |
| // |
| //***************************************************************************** |
| #if !defined(DOXYGEN) |
| #undef TRNGConfigure |
| #define TRNGConfigure NOROM_TRNGConfigure |
| #undef TRNGNumberGet |
| #define TRNGNumberGet NOROM_TRNGNumberGet |
| #endif |
| |
| //***************************************************************************** |
| // |
| //! Configure the true random number generator |
| // |
| //***************************************************************************** |
| void |
| TRNGConfigure(uint32_t ui32MinSamplesPerCycle, |
| uint32_t ui32MaxSamplesPerCycle, |
| uint32_t ui32ClocksPerSample) |
| { |
| uint32_t ui32Val; |
| |
| // |
| // Make sure the TRNG is disabled. |
| // |
| ui32Val = HWREG(TRNG_BASE + TRNG_O_CTL) & ~TRNG_CTL_TRNG_EN; |
| HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val; |
| |
| // |
| // Configure the startup number of samples. |
| // |
| ui32Val &= ~TRNG_CTL_STARTUP_CYCLES_M; |
| ui32Val |= ((( ui32MaxSamplesPerCycle >> 8 ) << TRNG_CTL_STARTUP_CYCLES_S ) & TRNG_CTL_STARTUP_CYCLES_M ); |
| HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val; |
| |
| // |
| // Configure the minimum and maximum number of samples pr generated number |
| // and the number of clocks per sample. |
| // |
| HWREG(TRNG_BASE + TRNG_O_CFG0) = ( |
| ((( ui32MaxSamplesPerCycle >> 8 ) << TRNG_CFG0_MAX_REFILL_CYCLES_S ) & TRNG_CFG0_MAX_REFILL_CYCLES_M ) | |
| ((( ui32ClocksPerSample ) << TRNG_CFG0_SMPL_DIV_S ) & TRNG_CFG0_SMPL_DIV_M ) | |
| ((( ui32MinSamplesPerCycle >> 6 ) << TRNG_CFG0_MIN_REFILL_CYCLES_S ) & TRNG_CFG0_MIN_REFILL_CYCLES_M ) ); |
| } |
| |
| //***************************************************************************** |
| // |
| //! Get a random number from the generator |
| // |
| //***************************************************************************** |
| uint32_t |
| TRNGNumberGet(uint32_t ui32Word) |
| { |
| uint32_t ui32RandomNumber; |
| |
| // |
| // Check the arguments. |
| // |
| ASSERT((ui32Word == TRNG_HI_WORD) || |
| (ui32Word == TRNG_LOW_WORD)); |
| |
| // |
| // Return the right requested part of the generated number. |
| // |
| if(ui32Word == TRNG_HI_WORD) |
| { |
| ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT1); |
| } |
| else |
| { |
| ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT0); |
| } |
| |
| // |
| // Initiate generation of new number. |
| // |
| HWREG(TRNG_BASE + TRNG_O_IRQFLAGCLR) = 0x1; |
| |
| // |
| // Return the random number. |
| // |
| return ui32RandomNumber; |
| } |