static uint8_t random_mutex;
+static void
+ao_trng_start(void)
+{
+ if (!trng_running) {
+ ao_mutex_get(&random_mutex);
+ if (!trng_running) {
+ AO_TICK_TYPE delay;
+
+ delay = trng_power_time + TRNG_ENABLE_DELAY - ao_time();
+ if (delay > TRNG_ENABLE_DELAY)
+ delay = TRNG_ENABLE_DELAY;
+
+ /* Delay long enough for the HV power supply
+ * to stabilize so that the first bits we read
+ * aren't of poor quality
+ */
+ ao_delay(delay);
+ trng_running = true;
+ }
+ ao_mutex_put(&random_mutex);
+ }
+}
+
#if AO_USB_HAS_IN2
static struct ao_task ao_trng_send_raw_task;
static void
ao_trng_send_raw(void)
{
- static uint16_t *buffer[2];
+ uint16_t *buffer[2];
int usb_buf_id;
- if (!buffer[0]) {
- buffer[0] = ao_usb_alloc();
- buffer[1] = ao_usb_alloc();
- if (!buffer[0])
- ao_exit();
- }
-
- usb_buf_id = 0;
+ usb_buf_id = ao_usb_alloc2(buffer);
for (;;) {
- ao_mutex_get(&random_mutex);
- if (!trng_running) {
- AO_TICK_TYPE delay;
-
- delay = trng_power_time + TRNG_ENABLE_DELAY - ao_time();
- if (delay > TRNG_ENABLE_DELAY)
- delay = TRNG_ENABLE_DELAY;
-
- /* Delay long enough for the HV power supply
- * to stabilize so that the first bits we read
- * aren't of poor quality
- */
- ao_delay(delay);
- trng_running = TRUE;
- }
+ ao_trng_start();
#ifdef AO_LED_TRNG_RAW
ao_led_on(AO_LED_TRNG_RAW);
#endif
#ifdef AO_LED_TRNG_RAW
ao_led_off(AO_LED_TRNG_RAW);
#endif
- ao_mutex_put(&random_mutex);
- ao_usb_write2(buffer[usb_buf_id], AO_USB_IN_SIZE);
- usb_buf_id = 1-usb_buf_id;
+ usb_buf_id = ao_usb_write2(AO_USB_IN_SIZE);
}
}
#endif
-/* Make sure there's at least 8 bits of variance in the samples */
-#define MIN_VARIANCE (128 * 128)
-
-/* Make sure the signal is spread around a bit */
-#define MAX_VARIANCE (512 * 512)
-
-#define ADD_STATS(value) do { \
- sum += (value); \
- sum2 += (value) * (value); \
- } while(0)
-
-#define VARIANCE(n) ((sum2 - (sum / (n) * sum)) / (n))
+static uint32_t previous[AO_USB_IN_SIZE / sizeof (uint16_t)];
static int
ao_trng_get_cooked(uint16_t *buf)
{
uint16_t i;
uint16_t t;
- uint32_t *rnd = (uint32_t *) ao_adc_ring;
- int32_t sum, sum2, var;
+ uint32_t *rnd = (uint32_t *) (void *) ao_adc_ring;
+ uint8_t mismatch = 1;
- sum = sum2 = 0;
t = ao_adc_get(AO_USB_IN_SIZE) >> 1; /* one 16-bit value per output byte */
for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
uint32_t v;
- uint16_t v1, v2;
/* Fetch two values in one operation */
v = rnd[t];
+ if (v != previous[i]) {
+ mismatch = 1;
+ previous[i] = v;
+ }
t = (t + 1) & ((AO_ADC_RING_SIZE >> 1) - 1);
*buf++ = ao_crc_in_32_out_16(v);
-
- v1 = v;
- v2 = v >> 16;
-
- ADD_STATS(v1);
- ADD_STATS(v2);
}
ao_adc_ack(AO_USB_IN_SIZE);
- var = VARIANCE(2 * AO_USB_IN_SIZE / sizeof (uint16_t));
- return var >= MIN_VARIANCE && var <= MAX_VARIANCE;
+ return mismatch;
}
#define AO_TRNG_START_WAIT 1024
static void
ao_trng_send(void)
{
- static uint16_t *buffer[2];
- int usb_buf_id;
- int good_bits;
- int failed;
- int s;
-
- if (!buffer[0]) {
- buffer[0] = ao_usb_alloc();
- buffer[1] = ao_usb_alloc();
- if (!buffer[0])
- ao_exit();
- }
+ uint16_t *buffer[2];
+ int usb_buf_id;
+ int good_bits;
+ int failed;
+ int s;
- usb_buf_id = 0;
+ usb_buf_id = ao_usb_alloc(buffer);
#ifdef AO_TRNG_ENABLE_PORT
ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
ao_crc_reset();
- ao_delay(TRNG_ENABLE_DELAY);
-
for (s = 0; s < AO_TRNG_START_WAIT; s++) {
- if (ao_trng_get_cooked(buffer[0]))
+ int i;
+ uint16_t min, max;
+ uint16_t buf[AO_USB_IN_SIZE>>1];
+
+ ao_trng_get_raw(buf);
+ min = max = buf[0];
+ for (i = 1; i < (AO_USB_IN_SIZE>>1); i++) {
+ uint16_t v = buf[i];
+ if (v < min) min = v;
+ if (v > max) max = v;
+ }
+ /* Wait for at least 10 bits of range */
+ if ((uint16_t) (max - min) >= 1024)
break;
ao_delay(AO_MS_TO_TICKS(10));
}
#endif
for (;;) {
- ao_mutex_get(&random_mutex);
- if (!trng_running) {
- AO_TICK_TYPE delay;
-
- delay = trng_power_time + TRNG_ENABLE_DELAY - ao_time();
- if (delay > TRNG_ENABLE_DELAY)
- delay = TRNG_ENABLE_DELAY;
-
- /* Delay long enough for the HV power supply
- * to stabilize so that the first bits we read
- * aren't of poor quality
- */
- ao_delay(delay);
- trng_running = TRUE;
- }
+ ao_trng_start();
#ifdef AO_LED_TRNG_COOKED
ao_led_on(AO_LED_TRNG_COOKED);
#endif
#ifdef AO_LED_TRNG_COOKED
ao_led_off(AO_LED_TRNG_COOKED);
#endif
- ao_mutex_put(&random_mutex);
if (good_bits) {
- ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
- usb_buf_id = 1-usb_buf_id;
+ usb_buf_id = ao_usb_write(AO_USB_IN_SIZE);
failed = 0;
} else {
failed++;
- ao_delay(AO_MS_TO_TICKS(10));
if (failed > 10) {
ao_usb_disable();
ao_panic(AO_PANIC_DMA);
#ifdef AO_TRNG_ENABLE_PORT
ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 0);
#endif
- trng_running = FALSE;
+ trng_running = false;
}
static void ao_trng_resume(void *arg)
projects / fw / altos / blobdiff