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Line 68... |
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int i;
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int i;
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TRNG_CT = 0; // reset
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TRNG_CT = 0; // reset
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for (i=0; i<1000; i++) {
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for (i=0; i<256; i++) {
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asm volatile ("nop");
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asm volatile ("nop");
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}
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}
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TRNG_CT = 1 << TRNG_CT_EN; // activate
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TRNG_CT = 1 << TRNG_CT_EN; // activate
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for (i=0; i<1000; i++) {
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for (i=0; i<256; i++) {
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asm volatile ("nop");
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asm volatile ("nop");
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}
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}
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Disable true random number generator.
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* Disable true random number generator.
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**************************************************************************/
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**************************************************************************/
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void neorv32_trng_disable(void) {
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void neorv32_trng_disable(void) {
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TRNG_CT &= ~((uint32_t)(1 << TRNG_CT_EN));
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TRNG_CT = 0;
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Get random data from TRNG.
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* Get random data byte from TRNG.
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*
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*
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* @note The TRNG is automatically reset if a stuck-at-one/stuck-at-zero error is detected.
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* @param[in,out] data uint8_t pointer for storing random data byte.
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*
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* @return Data is valid when 0 and invalid otherwise.
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* @param[in,out] data uint8_t pointer for storing random data word
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* @return Data is valid when 0, stuck-at-zero error when 1, stuck-at-one error when 2, data not (yet) valid when 3
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**************************************************************************/
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**************************************************************************/
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int neorv32_trng_get(uint8_t *data) {
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int neorv32_trng_get(uint8_t *data) {
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uint32_t trng_ct_reg = TRNG_CT;
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const int retries = 3;
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int i;
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if (trng_ct_reg & (1<<TRNG_CT_ERROR_0)) { // stuck at zero error
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uint32_t ct_reg;
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neorv32_trng_enable(); // reset TRNG
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return 1;
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}
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if (trng_ct_reg & (1<<TRNG_CT_ERROR_1)) { // stuck at one error
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for (i=0; i<retries; i++) {
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neorv32_trng_enable(); // reset TRNG
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ct_reg = TRNG_CT;
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return 2;
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}
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if ((trng_ct_reg & (1<<TRNG_CT_VALID)) == 0) { // output data valid (yet)?
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if ((ct_reg & (1<<TRNG_CT_VALID)) == 0) { // output data valid?
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return 3;
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continue;
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}
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}
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*data = (uint8_t)(trng_ct_reg >> TRNG_CT_DATA_LSB);
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*data = (uint8_t)(ct_reg >> TRNG_CT_DATA_LSB);
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return 0; // valid data
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return 0; // valid data
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}
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}
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return -1; // no valid data available
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}
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No newline at end of file
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No newline at end of file
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