1 /******************************************************************************
2 * Filename: trng.c
3 * Revised: 2017-04-26 18:27:45 +0200 (Wed, 26 Apr 2017)
4 * Revision: 48852
5 *
6 * Description: Driver for the TRNG module
7 *
8 * Copyright (c) 2015 - 2017, Texas Instruments Incorporated
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions are met:
13 *
14 * 1) Redistributions of source code must retain the above copyright notice,
15 * this list of conditions and the following disclaimer.
16 *
17 * 2) Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 *
21 * 3) Neither the name of the ORGANIZATION nor the names of its contributors may
22 * be used to endorse or promote products derived from this software without
23 * specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
26 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
29 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 *
37 ******************************************************************************/
38
39 #include "trng.h"
40
41 //*****************************************************************************
42 //
43 // Handle support for DriverLib in ROM:
44 // This section will undo prototype renaming made in the header file
45 //
46 //*****************************************************************************
47 #if !defined(DOXYGEN)
48 #undef TRNGConfigure
49 #define TRNGConfigure NOROM_TRNGConfigure
50 #undef TRNGNumberGet
51 #define TRNGNumberGet NOROM_TRNGNumberGet
52 #endif
53
54 //*****************************************************************************
55 //
56 // Configure the true random number generator
57 //
58 //*****************************************************************************
59 void
TRNGConfigure(uint32_t ui32MinSamplesPerCycle,uint32_t ui32MaxSamplesPerCycle,uint32_t ui32ClocksPerSample)60 TRNGConfigure(uint32_t ui32MinSamplesPerCycle,
61 uint32_t ui32MaxSamplesPerCycle,
62 uint32_t ui32ClocksPerSample)
63 {
64 uint32_t ui32Val;
65
66 // Make sure the TRNG is disabled.
67 ui32Val = HWREG(TRNG_BASE + TRNG_O_CTL) & ~TRNG_CTL_TRNG_EN;
68 HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val;
69
70 // Configure the startup number of samples.
71 ui32Val &= ~TRNG_CTL_STARTUP_CYCLES_M;
72 ui32Val |= ((( ui32MaxSamplesPerCycle >> 8 ) << TRNG_CTL_STARTUP_CYCLES_S ) & TRNG_CTL_STARTUP_CYCLES_M );
73 HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val;
74
75 // Configure the minimum and maximum number of samples pr generated number
76 // and the number of clocks per sample.
77 HWREG(TRNG_BASE + TRNG_O_CFG0) = (
78 ((( ui32MaxSamplesPerCycle >> 8 ) << TRNG_CFG0_MAX_REFILL_CYCLES_S ) & TRNG_CFG0_MAX_REFILL_CYCLES_M ) |
79 ((( ui32ClocksPerSample ) << TRNG_CFG0_SMPL_DIV_S ) & TRNG_CFG0_SMPL_DIV_M ) |
80 ((( ui32MinSamplesPerCycle >> 6 ) << TRNG_CFG0_MIN_REFILL_CYCLES_S ) & TRNG_CFG0_MIN_REFILL_CYCLES_M ) );
81 }
82
83 //*****************************************************************************
84 //
85 // Get a random number from the generator
86 //
87 //*****************************************************************************
88 uint32_t
TRNGNumberGet(uint32_t ui32Word)89 TRNGNumberGet(uint32_t ui32Word)
90 {
91 uint32_t ui32RandomNumber;
92
93 // Check the arguments.
94 ASSERT((ui32Word == TRNG_HI_WORD) ||
95 (ui32Word == TRNG_LOW_WORD));
96
97 // Return the right requested part of the generated number.
98 if(ui32Word == TRNG_HI_WORD)
99 {
100 ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT1);
101 }
102 else
103 {
104 ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT0);
105 }
106
107 // Initiate generation of new number.
108 HWREG(TRNG_BASE + TRNG_O_IRQFLAGCLR) = 0x1;
109
110 // Return the random number.
111 return ui32RandomNumber;
112 }
113
