1 /******************************************************************************
2 * Copyright (c) 2022 Telink Semiconductor (Shanghai) Co., Ltd. ("TELINK")
3 * All rights reserved.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 *****************************************************************************/
18 #include "trng.h"
19 #include "compiler.h"
20 /**********************************************************************************************************************
21 * local constants *
22 *********************************************************************************************************************/
23
24 /**********************************************************************************************************************
25 * local macro *
26 *********************************************************************************************************************/
27
28 /**********************************************************************************************************************
29 * local data type *
30 *********************************************************************************************************************/
31
32 /**********************************************************************************************************************
33 * global variable *
34 *********************************************************************************************************************/
35
36 _attribute_data_retention_sec_ unsigned int g_rnd_m_w = 0;
37 _attribute_data_retention_sec_ unsigned int g_rnd_m_z = 0;
38
39 /**********************************************************************************************************************
40 * local variable *
41 *********************************************************************************************************************/
42 /**********************************************************************************************************************
43 * local function prototype *
44 *********************************************************************************************************************/
45 /**********************************************************************************************************************
46 * global function implementation *
47 *********************************************************************************************************************/
48 /**
49 * @brief This function performs to get one random number.If chip in suspend TRNG module should be close.
50 * else its current will be larger.
51 * @return the value of one random number.
52 */
trng_init(void)53 void trng_init(void)
54 {
55 // TRNG module Reset clear
56 reg_rst2 |= FLD_RST2_TRNG;
57 // turn on TRNG clock
58 reg_clk_en2 |= FLD_CLK2_TRNG_EN;
59
60 reg_trng_cr0 &= ~(FLD_TRNG_CR0_RBGEN); // disable
61 reg_trng_rtcr = 0x00; // TCR_MSEL
62 reg_trng_cr0 |= (FLD_TRNG_CR0_RBGEN); // enable
63
64 while (!(reg_rbg_sr & FLD_RBG_SR_DRDY)) {
65 }
66
67 g_rnd_m_w = reg_rbg_dr; // get the random number
68 while (!(reg_rbg_sr & FLD_RBG_SR_DRDY)) {
69 }
70
71 g_rnd_m_z = reg_rbg_dr;
72
73 // Reset TRNG module
74 reg_rst2 &= (~FLD_RST2_TRNG);
75 // turn off TRNG module clock
76 reg_clk_en2 &= ~(FLD_CLK2_TRNG_EN);
77
78 reg_trng_cr0 &=
79 ~(FLD_TRNG_CR0_RBGEN | FLD_TRNG_CR0_ROSEN0 | FLD_TRNG_CR0_ROSEN1 | FLD_TRNG_CR0_ROSEN2 | FLD_TRNG_CR0_ROSEN3);
80 }
81
82 /**
83 * @brief This function performs to get one random number.
84 * @return the value of one random number.
85 */
trng_rand(void)86 _attribute_ram_code_sec_noinline_ unsigned int trng_rand(void) // 16M clock, code in flash 23us, code in sram 4us
87 {
88 g_rnd_m_w = 18000 * (g_rnd_m_w & 0xffff) + (g_rnd_m_w >> 16);
89 g_rnd_m_z = 36969 * (g_rnd_m_z & 0xffff) + (g_rnd_m_z >> 16);
90 unsigned int result = (g_rnd_m_z << 16) + g_rnd_m_w;
91
92 return (unsigned int)(result ^ stimer_get_tick());
93 }
94 /**********************************************************************************************************************
95 * local function implementation *
96 *********************************************************************************************************************/
97