X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Fdrivers%2Fao_trng_send.c;fp=src%2Fdrivers%2Fao_trng_send.c;h=171a345fbe2db047feebaab19c25a55ba03410e9;hb=05fcb717bfc44aba3c1cfd43281e323505a46402;hp=f82229934c177f11e724d773afebd54433f7e82a;hpb=05354b8fee6a9af05d66bb7f4761f597da038fdd;p=fw%2Faltos diff --git a/src/drivers/ao_trng_send.c b/src/drivers/ao_trng_send.c index f8222993..171a345f 100644 --- a/src/drivers/ao_trng_send.c +++ b/src/drivers/ao_trng_send.c @@ -22,54 +22,97 @@ #include #include +static struct ao_task ao_trng_send_task, ao_trng_send_raw_task; 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) +static uint8_t random_mutex; + +static void +ao_trng_get_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); + } + ao_adc_ack(AO_USB_IN_SIZE>>1); +} + +static void +ao_trng_send_raw(void) +{ + static uint16_t *buffer[2]; + int usb_buf_id; - ADD_STATS(v); + if (!buffer[0]) { + buffer[0] = ao_usb_alloc(); + buffer[1] = ao_usb_alloc(); + if (!buffer[0]) + ao_exit(); + } + + usb_buf_id = 0; + + 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; + } +#ifdef AO_LED_TRNG_RAW + ao_led_on(AO_LED_TRNG_RAW); +#endif + ao_trng_get_raw(buffer[usb_buf_id]); +#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; } - return GOOD_STATS(AO_USB_IN_SIZE / sizeof (uint16_t)); } +/* 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 int -ao_trng_send_cooked(uint16_t *buf) +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; - DECLARE_STATS; - + 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; @@ -86,14 +129,13 @@ ao_trng_send_cooked(uint16_t *buf) ADD_STATS(v1); ADD_STATS(v2); } - return GOOD_STATS(2 * AO_USB_IN_SIZE / sizeof (uint16_t)); + ao_adc_ack(AO_USB_IN_SIZE); + var = VARIANCE(2 * AO_USB_IN_SIZE / sizeof (uint16_t)); + return var >= MIN_VARIANCE && var <= MAX_VARIANCE; } -static inline int -ao_send_raw(void) -{ - return !ao_gpio_get(AO_RAW_PORT, AO_RAW_BIT, AO_RAW_PIN); -} +#define AO_TRNG_START_WAIT 1024 +#define AO_TRNG_START_CHECK 32 static void ao_trng_send(void) @@ -101,13 +143,14 @@ ao_trng_send(void) static uint16_t *buffer[2]; int usb_buf_id; int good_bits; - int failed = 0; + int failed; + int s; if (!buffer[0]) { buffer[0] = ao_usb_alloc(); buffer[1] = ao_usb_alloc(); if (!buffer[0]) - return; + ao_exit(); } usb_buf_id = 0; @@ -119,7 +162,33 @@ 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])) + break; + ao_delay(AO_MS_TO_TICKS(10)); + } + + /* Validate the hardware before enabling USB */ + failed = 0; + for (s = 0; s < AO_TRNG_START_CHECK; s++) { + if (!ao_trng_get_cooked(buffer[0])) { + failed++; + ao_delay(AO_MS_TO_TICKS(10)); + } + } + if (failed > AO_TRNG_START_CHECK / 4) + ao_panic(AO_PANIC_DMA); + + ao_add_task(&ao_trng_send_raw_task, ao_trng_send_raw, "trng_send_raw"); + +#ifdef AO_USB_START_DISABLED + ao_usb_enable(); +#endif + for (;;) { + ao_mutex_get(&random_mutex); if (!trng_running) { AO_TICK_TYPE delay; @@ -134,16 +203,14 @@ ao_trng_send(void) 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); +#ifdef AO_LED_TRNG_COOKED + ao_led_on(AO_LED_TRNG_COOKED); +#endif + good_bits = ao_trng_get_cooked(buffer[usb_buf_id]); +#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; @@ -159,8 +226,6 @@ ao_trng_send(void) } } -static struct ao_task ao_trng_send_task; - #if AO_POWER_MANAGEMENT static void ao_trng_suspend(void *arg)