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trng.c
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1 /******************************************************************************
2 * Filename: trng.c
3 * Revised: 2015-01-13 16:59:55 +0100 (ti, 13 jan 2015)
4 * Revision: 42365
5 *
6 * Description: Driver for the TRNG module
7 *
8 * Copyright (c) 2015, 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 <driverlib/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 #ifndef DRIVERLIB_GENERATE_ROM
48 #undef TRNGConfigure
49 #define TRNGConfigure NOROM_TRNGConfigure
50 #undef TRNGNumberGet
51 #define TRNGNumberGet NOROM_TRNGNumberGet
52 #endif
53
54 //*****************************************************************************
55 //
57 //
58 //*****************************************************************************
59 void
60 TRNGConfigure(uint32_t ui32MinSamplesPerCycle,
61 uint32_t ui32MaxSamplesPerCycle,
62 uint32_t ui32ClocksPerSample)
63 {
64 uint32_t ui32Val;
65
66 //
67 // Make sure the TRNG is disabled.
68 //
69 ui32Val = HWREG(TRNG_BASE + TRNG_O_CTL) & ~TRNG_CTL_TRNG_EN;
70 HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val;
71
72 //
73 // Configure the startup number of samples.
74 //
75 ui32Val &= ~TRNG_CTL_STARTUP_CYCLES_M;
76 ui32Val |= ((ui32MaxSamplesPerCycle >> 8) & 0xFFFF) << 16;
77 HWREG(TRNG_BASE + TRNG_O_CTL) = ui32Val;
78
79 //
80 // Configure the minimum and maximum number of samples pr generated number
81 // and the number of clocks per sample.
82 //
83 HWREG(TRNG_BASE + TRNG_O_CFG0) =
84 (((ui32MaxSamplesPerCycle >> 8) & 0xFFFF) << 16) |
85 ((ui32ClocksPerSample & 0xFF) << 8) |
86 ((ui32MinSamplesPerCycle >> 6) & 0xFF);
87 }
88
89 //*****************************************************************************
90 //
92 //
93 //*****************************************************************************
94 uint32_t
95 TRNGNumberGet(uint32_t ui32Word)
96 {
97 uint32_t ui32RandomNumber;
98
99 //
100 // Check the arguments.
101 //
102 ASSERT((ui32Word == TRNG_HI_WORD) ||
103 (ui32Word == TRNG_LOW_WORD));
104
105 //
106 // Return the right requested part of the generated number.
107 //
108 if(ui32Word == TRNG_HI_WORD)
109 {
110 ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT1);
111 }
112 else
113 {
114 ui32RandomNumber = HWREG(TRNG_BASE + TRNG_O_OUT0);
115 }
116
117 //
118 // Initiate generation of new number.
119 //
120 HWREG(TRNG_BASE + TRNG_O_IRQFLAGCLR) = 0x1;
121
122 //
123 // Return the random number.
124 //
125 return ui32RandomNumber;
126 }
TRNG_HI_WORD
#define TRNG_HI_WORD
Definition: trng.h:99
ASSERT
#define ASSERT(expr)
Definition: debug.h:65
TRNGNumberGet
uint32_t TRNGNumberGet(uint32_t ui32Word)
Get a random number from the generator.
Definition: trng.c:95
TRNGConfigure
void TRNGConfigure(uint32_t ui32MinSamplesPerCycle, uint32_t ui32MaxSamplesPerCycle, uint32_t ui32ClocksPerSample)
Configure the true random number generator.
Definition: trng.c:60
TRNG_LOW_WORD
#define TRNG_LOW_WORD
Definition: trng.h:100
trng.h