48 lines
1.1 KiB
C
48 lines
1.1 KiB
C
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// Use hardware RNG peripheral
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// Working with HAL, LL Driver (untested)
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#ifdef STM32F4
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#include "stm32f4xx.h"
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static int
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hydro_random_init(void)
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{
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const char ctx[hydro_hash_CONTEXTBYTES] = { 'h', 'y', 'd', 'r', 'o', 'P', 'R', 'G' };
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hydro_hash_state st;
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uint16_t ebits = 0;
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__IO uint32_t tmpreg;
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// Enable RNG clock source
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SET_BIT(RCC->AHB2ENR, RCC_AHB2ENR_RNGEN);
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// Delay after an RCC peripheral clock enabling
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tmpreg = READ_BIT(RCC->AHB2ENR, RCC_AHB2ENR_RNGEN);
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UNUSED(tmpreg);
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// RNG Peripheral enable
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SET_BIT(RNG->CR, RNG_CR_RNGEN);
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hydro_hash_init(&st, ctx, NULL);
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while (ebits < 256) {
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while (!(READ_BIT(RNG->SR, RNG_SR_DRDY))) {
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}
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uint32_t r = RNG->DR;
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hydro_hash_update(&st, (const uint32_t*) &r, sizeof r);
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ebits += 32;
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}
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hydro_hash_final(&st, hydro_random_context.state, sizeof hydro_random_context.state);
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hydro_random_context.counter = ~LOAD64_LE(hydro_random_context.state);
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return 0;
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}
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#else
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# error SMT32 implementation missing!
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#endif
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