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nrf: Call into sd as many times as necessary to fill urandom request

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Generating 51200 bytes in one go takes 4.966s, so that's a rate of about
10KiB/s.
This commit is contained in:
Jeff Epler 2020-01-08 10:06:55 -06:00
parent 6735283d8f
commit b3fb024301
1 changed files with 20 additions and 2 deletions
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22
ports/nrf/common-hal/os/__init__.c
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@ -31,6 +31,7 @@
#ifdef BLUETOOTH_SD
#include "nrf_sdm.h"
#include "tick.h"
#endif
#include "nrf_rng.h"
@ -66,8 +67,25 @@ bool common_hal_os_urandom(uint8_t *buffer, uint32_t length) {
uint8_t sd_en = 0;
(void) sd_softdevice_is_enabled(&sd_en);
if (sd_en)
return NRF_SUCCESS == sd_rand_application_vector_get(buffer, length);
if (sd_en) {
while (length != 0) {
uint8_t available = 0;
sd_rand_application_bytes_available_get(&available);
if (available) {
uint32_t request = MIN(length, available);
uint32_t result = sd_rand_application_vector_get(buffer, request);
if (result != NRF_SUCCESS) {
return false;
}
buffer += request;
length -= request;
} else {
RUN_BACKGROUND_TASKS;
tick_delay(500);
}
}
return true;
}
#endif
nrf_rng_event_clear(NRF_RNG, NRF_RNG_EVENT_VALRDY);