X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Fdrivers%2Fao_trng_send.c;h=f82229934c177f11e724d773afebd54433f7e82a;hb=bab082605e3fca6b6d11447c45cd948ddfe74bb9;hp=bac6035cd8dbde1b09fdb929debc5fc4b67a8c80;hpb=b1b69c8b73cbffb56c688f6a968d144b642cdff2;p=fw%2Faltos

diff --git a/src/drivers/ao_trng_send.c b/src/drivers/ao_trng_send.c
index bac6035c..f8222993 100644
--- a/src/drivers/ao_trng_send.c
+++ b/src/drivers/ao_trng_send.c
@@ -19,17 +19,90 @@
 #include <ao_adc_fast.h>
 #include <ao_crc.h>
 #include <ao_trng_send.h>
+#include <ao_exti.h>
+#include <ao_power.h>
 
-static void
-ao_trng_send(void)
+static uint8_t		trng_running;
+static AO_TICK_TYPE	trng_power_time;
+
+/* Make sure there's at least 8 bits of variance in the samples */
+#define MIN_VARIANCE		(128 * 128)
+
+#define DECLARE_STATS	int32_t sum = 0, sum2 = 0
+
+#define ADD_STATS(value) do {			\
+		sum += (value);			\
+		sum2 += (value) * (value);	\
+	} while(0)
+
+#define GOOD_STATS(i)	(((sum2 - (sum * sum) / i) / i) >= MIN_VARIANCE)
+
+#define TRNG_ENABLE_DELAY	AO_MS_TO_TICKS(100)
+
+static int
+ao_trng_send_raw(uint16_t *buf)
+{
+	uint16_t	i;
+	uint16_t	t;
+	uint16_t	v;
+
+	DECLARE_STATS;
+
+	t = ao_adc_get(AO_USB_IN_SIZE>>1);	/* one 16-bit value per two output bytes */
+	for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
+		v = ao_adc_ring[t];
+		*buf++ = v;
+		t = (t + 1) & (AO_ADC_RING_SIZE - 1);
+
+		ADD_STATS(v);
+	}
+	return GOOD_STATS(AO_USB_IN_SIZE / sizeof (uint16_t));
+}
+
+static int
+ao_trng_send_cooked(uint16_t *buf)
 {
-	static uint16_t	*buffer[2];
-	int		usb_buf_id;
 	uint16_t	i;
-	uint16_t	*buf;
 	uint16_t	t;
 	uint32_t	*rnd = (uint32_t *) ao_adc_ring;
 
+	DECLARE_STATS;
+
+	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];
+		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);
+	}
+	return GOOD_STATS(2 * AO_USB_IN_SIZE / sizeof (uint16_t));
+}
+
+static inline int
+ao_send_raw(void)
+{
+	return !ao_gpio_get(AO_RAW_PORT, AO_RAW_BIT, AO_RAW_PIN);
+}
+
+static void
+ao_trng_send(void)
+{
+	static uint16_t	*buffer[2];
+	int	usb_buf_id;
+	int	good_bits;
+	int	failed = 0;
+
 	if (!buffer[0]) {
 		buffer[0] = ao_usb_alloc();
 		buffer[1] = ao_usb_alloc();
@@ -39,27 +112,89 @@ ao_trng_send(void)
 
 	usb_buf_id = 0;
 
+#ifdef AO_TRNG_ENABLE_PORT
+	ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
+#endif
+	trng_power_time = ao_time();
+
 	ao_crc_reset();
 
 	for (;;) {
-		ao_led_on(AO_LED_TRNG_ACTIVE);
-		t = ao_adc_get(AO_USB_IN_SIZE) >> 1;	/* one 16-bit value per output byte */
-		buf = buffer[usb_buf_id];
-		for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
-			*buf++ = ao_crc_in_32_out_16(rnd[t]);
-			t = (t + 1) & ((AO_ADC_RING_SIZE>>1) - 1);
+		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;
+		}
+		if (ao_send_raw()) {
+			ao_led_on(AO_LED_TRNG_RAW);
+			good_bits = ao_trng_send_raw(buffer[usb_buf_id]);
+			ao_led_off(AO_LED_TRNG_RAW);
+		} else {
+			ao_led_on(AO_LED_TRNG_COOKED);
+			good_bits = ao_trng_send_cooked(buffer[usb_buf_id]);
+			ao_led_off(AO_LED_TRNG_COOKED);
 		}
 		ao_adc_ack(AO_USB_IN_SIZE);
-		ao_led_off(AO_LED_TRNG_ACTIVE);
-		ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
-		usb_buf_id = 1-usb_buf_id;
+		if (good_bits) {
+			ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
+			usb_buf_id = 1-usb_buf_id;
+			failed = 0;
+		} else {
+			failed++;
+			ao_delay(AO_MS_TO_TICKS(10));
+			if (failed > 10) {
+				ao_usb_disable();
+				ao_panic(AO_PANIC_DMA);
+			}
+		}
 	}
 }
 
 static struct ao_task ao_trng_send_task;
 
+#if AO_POWER_MANAGEMENT
+
+static void ao_trng_suspend(void *arg)
+{
+	(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;
+}
+
+static void ao_trng_resume(void *arg)
+{
+	(void) arg;
+#ifdef AO_TRNG_ENABLE_PORT
+	ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
+#endif
+	trng_power_time = ao_time();
+}
+
+static struct ao_power ao_trng_power = {
+	.suspend = ao_trng_suspend,
+	.resume = ao_trng_resume
+};
+
+#endif
+
 void
 ao_trng_send_init(void)
 {
+#ifdef AO_TRNG_ENABLE_PORT
+	ao_enable_output(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 0);
+	ao_power_register(&ao_trng_power);
+#endif
+	ao_enable_input(AO_RAW_PORT, AO_RAW_BIT, AO_EXTI_MODE_PULL_UP);
 	ao_add_task(&ao_trng_send_task, ao_trng_send, "trng_send");
 }