Call POST / ao_trng_reset() lazily

renamed ao_reset() to ao_trng_reset() and
  ao_status() to ao_trng_status()
moved the failure handling to ao_trng_failure()

CAUTION: this version 1.6.3 will fail to load the command processor!

3 files changed, 72 insertions, 104 deletions

diff --git a/src/drivers/ao_trng.c b/src/drivers/ao_trng.c
index b8e25e28..d3c2823a 100644
--- a/src/drivers/ao_trng.c
+++ b/src/drivers/ao_trng.c
@@ -20,23 +20,6 @@
 #include <ao_crc.h>
 #include <ao_trng.h>
 
-
-static struct ao_task ao_blink_red_task;
-static uint8_t ao_failed = 0;
-
-static void
-ao_blink_red(void)
-{
-	for (;;) {
-		while (!ao_failed)
-			ao_sleep(&ao_failed);
-		while (ao_failed) {
-			ao_led_toggle(AO_LED_RED);
-			ao_delay(AO_MS_TO_TICKS(500));
-		}
-	}
-}
-
 static struct ao_task ao_blink_green_task;
 static uint8_t ao_blinking_green = 0;
 
@@ -63,86 +46,31 @@ ao_blink_green_toggle(void)
 	ao_wakeup(&ao_blinking_green);
 }
 
-#define ADC_WORDS (AO_USB_IN_SIZE / sizeof (uint16_t))
-static uint16_t prev16 = 0;
-static uint16_t	adc_values[ADC_WORDS];
-static uint8_t	adc_i = ADC_WORDS;
-
-static uint16_t
-fetch16(uint8_t initialize)
-{
-	uint32_t	*rnd;
-	uint8_t		i;
-
-	if (ao_failed)
-		return 0;
-	if (initialize)
-		adc_i = ADC_WORDS;
-	if (adc_i == ADC_WORDS) {
-		rnd = (uint32_t *) ao_adc_get(AO_USB_IN_SIZE);	/* one 16-bit value per output byte */
-		adc_i = 0;
-		for (i = 0; i < ADC_WORDS; i++) {
-			adc_values[i] = ao_crc_in_32_out_16(*rnd++);
-		}
-	}
-	if (initialize)
-		prev16 = adc_values[adc_i++];
-	if (adc_values[adc_i] == prev16) {
-		/* FAILED: how do we prevent spewing bad data? */
-		printf("FAILED value %d repeated\n", prev16);
-		ao_failed = 1;
-		ao_wakeup(&ao_failed);
-		return 0;
-	}
-	prev16 = adc_values[adc_i];
-	adc_i++;
-	return prev16;
-}
-
-static void
-ao_simulate_failure(void)
-{
-	if (adc_i == ADC_WORDS)
-		fetch16(0);
-	prev16 = adc_values[adc_i];
-}
+static struct ao_task ao_blink_red_task;
+static int8_t ao_failed = -1; /* -1 need POST, 0 NOMINAL, 1 FAILED */
 
-/* NOTE: the reset function also functions as the Power On Self Test */
+/* On handling failure, keithp said:
+ We could disconnect from USB easily enough, or disconnect and come back
+ with a different setup that the kernel driver could report as an
+ error. Lots of options.
+*/
 void
-ao_reset(void)
+ao_trng_failure(void)
 {
-	uint32_t	count;
-
-	printf("Power On Self Test\n"); /* DEBUGGING */
-	ao_failed = 0;
-	ao_led_off(AO_LED_RED);
+	ao_failed = 1;
 	ao_wakeup(&ao_failed);
-	fetch16(1);
-	/* get the first 1k bits and ensure there are no duplicates */
-	count = 1024 / sizeof (uint16_t);
-	while (count-- && !ao_failed) {
-		fetch16(0);
-	}
-	if (ao_failed) { /* show failure */
-		printf("FAILED self test\n");
-	} else { /* show success */
-		printf("PASS - operation NOMINAL\n");
-		/* this blocks! */
-		ao_led_on(AO_LED_GREEN);
-		ao_delay(AO_MS_TO_TICKS(1000));
-		ao_led_off(AO_LED_GREEN);
-	}
 }
 
 static void
-ao_trng_fetch(void)
+ao_trng_fetch(uint32_t kbytes)
 {
 	static uint16_t	*buffer[2];
-	uint32_t	kbytes = 1;
 	uint32_t	count;
 	int		usb_buf_id;
 	uint16_t	i;
 	uint16_t	*buf;
+	uint32_t        *rnd;
+	uint32_t        prev, cur;
 
 	if (!buffer[0]) {
 		buffer[0] = ao_usb_alloc();
@@ -151,11 +79,6 @@ ao_trng_fetch(void)
 			return;
 	}
 
-	ao_cmd_decimal();
-	if (ao_cmd_status == ao_cmd_success)
-		kbytes = ao_cmd_lex_u32;
-	else
-		ao_cmd_status = ao_cmd_success;
 	usb_buf_id = 0;
 	count = kbytes * (1024/AO_USB_IN_SIZE);
 
@@ -163,9 +86,17 @@ ao_trng_fetch(void)
 
 	ao_led_on(AO_LED_TRNG_READ);
 	while (count--) {
+		/* one 16-bit value per output byte */
+		rnd = (uint32_t *) ao_adc_get(AO_USB_IN_SIZE + 2);
 		buf = buffer[usb_buf_id];
-		for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++)
-			*buf++ = fetch16(0);
+		prev = *rnd++;
+		for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
+			cur = *rnd++;
+			if (cur == prev)
+				ao_trng_failure();
+			*buf++ = ao_crc_in_32_out_16(cur);
+			prev = cur;
+		}
 		ao_adc_ack(AO_USB_IN_SIZE);
 		ao_led_toggle(AO_LED_TRNG_READ|AO_LED_TRNG_WRITE);
 		ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
@@ -177,13 +108,56 @@ ao_trng_fetch(void)
 }
 
 static void
-ao_trng_word(void)
+ao_trng_fetch_cmd(void)
 {
-	printf("%d\n", fetch16(0));
+	uint32_t kbytes = 1;
+
+	ao_cmd_decimal();
+	if (ao_cmd_status == ao_cmd_success)
+		kbytes = ao_cmd_lex_u32;
+	else
+		ao_cmd_status = ao_cmd_success;
+	ao_trng_fetch(kbytes);
+}
+
+/* NOTE: the reset function also functions as the Power On Self Test */
+void
+ao_trng_reset(void)
+{
+	printf("Power On Self Test\n"); /* DEBUGGING */
+	ao_failed = 0;
+	ao_led_off(AO_LED_RED);
+	ao_wakeup(&ao_failed);
+	/* get the first 1k bits and ensure there are no duplicates */
+	ao_trng_fetch(1);
+	if (ao_failed) { /* show failure */
+		printf("FAILED self test\n");
+	} else { /* show success */
+		printf("PASS - operation NOMINAL\n");
+		/* this blocks! */
+		ao_led_on(AO_LED_GREEN);
+		ao_delay(AO_MS_TO_TICKS(1000));
+		ao_led_off(AO_LED_GREEN);
+	}
+}
+
+static void
+ao_blink_red(void)
+{
+	if (ao_failed < 0)
+		ao_trng_reset(); /* lazy POST */
+	for (;;) {
+		while (!ao_failed)
+			ao_sleep(&ao_failed);
+		while (ao_failed) {
+			ao_led_toggle(AO_LED_RED);
+			ao_delay(AO_MS_TO_TICKS(500));
+		}
+	}
 }
 
 static void
-ao_status(void)
+ao_trng_status(void)
 {
 	if (ao_failed)
 		printf("FAILED\n");
@@ -192,12 +166,11 @@ ao_status(void)
 }
 
 static const struct ao_cmds ao_trng_cmds[] = {
-	{ ao_trng_fetch, "f <kbytes>\0Fetch a block of numbers" },
-	{ ao_trng_word, "F\0Fetch 16 bit unsigned int" },
-	{ ao_reset, "R\0reset" },
+	{ ao_trng_fetch_cmd, "f <kbytes>\0Fetch a block of numbers" },
+	{ ao_trng_reset, "R\0Reset" },
 	{ ao_blink_green_toggle, "G\0Toggle green LED blinking" },
-	{ ao_status, "s\0show status" },
-	{ ao_simulate_failure, "z\0simulate failure" },
+	{ ao_trng_status, "s\0Show status" },
+	{ ao_trng_failure, "z\0Simulate failure" },
 	{ 0, NULL },
 };
 
diff --git a/src/drivers/ao_trng.h b/src/drivers/ao_trng.h
index 089c70c6..78577428 100644
--- a/src/drivers/ao_trng.h
+++ b/src/drivers/ao_trng.h
@@ -21,7 +21,4 @@
 void
 ao_trng_init(void);
 
-void
-ao_reset(void);
-
 #endif /* _AO_TRNG_H_ */
diff --git a/src/usbtrng-v2.0/ao_usbtrng.c b/src/usbtrng-v2.0/ao_usbtrng.c
index d4a75197..42713b6e 100644
--- a/src/usbtrng-v2.0/ao_usbtrng.c
+++ b/src/usbtrng-v2.0/ao_usbtrng.c
@@ -40,6 +40,4 @@ void main(void)
 	ao_led_off(AO_LED_RED);
 
 	ao_start_scheduler();
-
-	ao_reset(); /* Power On Self Test */
 }