int usb_buf_id;
uint16_t i;
uint16_t *buf;
- uint32_t *rnd;
+ uint16_t t;
+ uint32_t *rnd = (uint32_t *) ao_adc_ring;
if (!buffer[0]) {
buffer[0] = ao_usb_alloc();
ao_led_on(AO_LED_TRNG_READ);
while (count--) {
- rnd = (uint32_t *) ao_adc_get(AO_USB_IN_SIZE); /* one 16-bit value per output byte */
+ 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++);
+ 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);
+ }
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);
int usb_buf_id;
uint16_t i;
uint16_t *buf;
- uint32_t *rnd;
+ uint16_t t;
+ uint32_t *rnd = (uint32_t *) ao_adc_ring;
if (!buffer[0]) {
buffer[0] = ao_usb_alloc();
for (;;) {
ao_led_on(AO_LED_TRNG_ACTIVE);
- rnd = (uint32_t *) ao_adc_get(AO_USB_IN_SIZE); /* one 16-bit value per output byte */
+ 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++);
+ 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);
+ }
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);
/* Maximum number of samples fetched per _ao_adc_start call */
#define AO_ADC_RING_CHUNK (AO_ADC_RING_SIZE >> 1)
-uint16_t ao_adc_ring_head, ao_adc_ring_tail;
+uint16_t ao_adc_ring_head, ao_adc_ring_remain;
uint16_t ao_adc_running;
/*
{
(void) index;
ao_adc_ring_head += ao_adc_running;
+ ao_adc_ring_remain += ao_adc_running;
if (ao_adc_ring_head == AO_ADC_RING_SIZE)
ao_adc_ring_head = 0;
ao_adc_running = 0;
#define ao_adc_ring_step(pos,inc) (((pos) + (inc)) & (AO_ADC_RING_SIZE - 1))
-extern uint16_t ao_adc_ring_head, ao_adc_ring_tail;
+extern uint16_t ao_adc_ring_head, ao_adc_ring_remain;
extern uint16_t ao_adc_running;
-void
-_ao_adc_start(void);
-
+/*
+ * Place to start fetching values from
+ */
static inline uint16_t
-_ao_adc_remain(void)
+ao_adc_ring_tail(void)
{
- if (ao_adc_ring_tail > ao_adc_ring_head)
- return AO_ADC_RING_SIZE - ao_adc_ring_tail;
- return ao_adc_ring_head - ao_adc_ring_tail;
+ return (ao_adc_ring_head - ao_adc_ring_remain) & (AO_ADC_RING_SIZE - 1);
}
+void
+_ao_adc_start(void);
+
+/*
+ * Space available to write ADC values into
+ */
static inline uint16_t
_ao_adc_space(void)
{
- if (ao_adc_ring_head >= ao_adc_ring_tail)
+ /* Free to end of buffer? */
+ if (ao_adc_ring_remain <= ao_adc_ring_head)
return AO_ADC_RING_SIZE - ao_adc_ring_head;
- return ao_adc_ring_tail - ao_adc_ring_head;
+
+ /* no, return just the unused entries beyond head */
+ return AO_ADC_RING_SIZE - ao_adc_ring_remain;
}
-static inline uint16_t *
+static inline uint16_t
ao_adc_get(uint16_t n)
{
- if (ao_adc_ring_tail + n > AO_ADC_RING_SIZE)
- ao_panic(AO_PANIC_ADC);
ao_arch_block_interrupts();
- while (_ao_adc_remain() < n) {
+ while (ao_adc_ring_remain < n) {
if (!ao_adc_running)
_ao_adc_start();
ao_sleep(&ao_adc_ring_head);
}
ao_arch_release_interrupts();
- return &ao_adc_ring[ao_adc_ring_tail];
+ return ao_adc_ring_tail();
}
static inline void
ao_adc_ack(uint16_t n)
{
- if (ao_adc_ring_tail + n > AO_ADC_RING_SIZE)
- ao_panic(AO_PANIC_ADC);
ao_arch_block_interrupts();
- ao_adc_ring_tail += n;
- if (ao_adc_ring_tail == AO_ADC_RING_SIZE)
- ao_adc_ring_tail = 0;
+ ao_adc_ring_remain -= n;
if (!ao_adc_running)
_ao_adc_start();
ao_arch_release_interrupts();