X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=src%2Fdrivers%2Fao_trng_send.c;h=e8df4cea8e69f25861a73a81acfedcc5f372dfad;hp=00efa8d9e336ff5787a507c76b65e1af56152000;hb=684741765117611b7d666efbdfafd87c6199752c;hpb=1085ec5d57e0ed5d132f2bbdac1a0b6a32c0ab4a

diff --git a/src/drivers/ao_trng_send.c b/src/drivers/ao_trng_send.c
index 00efa8d9..e8df4cea 100644
--- a/src/drivers/ao_trng_send.c
+++ b/src/drivers/ao_trng_send.c
@@ -31,6 +31,29 @@ static AO_TICK_TYPE	trng_power_time;
 
 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;
@@ -54,34 +77,13 @@ ao_trng_get_raw(uint16_t *buf)
 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
@@ -89,56 +91,38 @@ ao_trng_send_raw(void)
 #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
@@ -147,20 +131,13 @@ ao_trng_get_cooked(uint16_t *buf)
 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);
@@ -169,10 +146,20 @@ ao_trng_send(void)
 
 	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));
 	}
@@ -197,21 +184,7 @@ ao_trng_send(void)
 #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
@@ -219,14 +192,11 @@ ao_trng_send(void)
 #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);
@@ -243,7 +213,7 @@ static void ao_trng_suspend(void *arg)
 #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)