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/*
* Copyright © 2015 Keith Packard <keithp@keithp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <ao.h>
#include <ao_adc_fast.h>
#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;
static void
ao_blink_green(void)
{
for (;;) {
while (!ao_blinking_green)
ao_sleep(&ao_blinking_green);
while (ao_blinking_green) {
ao_led_toggle(AO_LED_GREEN);
ao_delay(AO_MS_TO_TICKS(1000));
}
}
}
static void
ao_blink_green_toggle(void)
{
ao_blinking_green = !ao_blinking_green;
if (!ao_blinking_green)
ao_led_off(AO_LED_GREEN);
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];
}
/* NOTE: the reset function also functions as the Power On Self Test */
void
ao_reset(void)
{
uint32_t count;
printf("Power On Self Test\n"); /* DEBUGGING */
ao_failed = 0;
ao_led_off(AO_LED_RED);
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)
{
static uint16_t *buffer[2];
uint32_t kbytes = 1;
uint32_t count;
int usb_buf_id;
uint16_t i;
uint16_t *buf;
if (!buffer[0]) {
buffer[0] = ao_usb_alloc();
buffer[1] = ao_usb_alloc();
if (!buffer[0])
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);
ao_crc_reset();
ao_led_on(AO_LED_TRNG_READ);
while (count--) {
buf = buffer[usb_buf_id];
for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++)
*buf++ = fetch16(0);
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);
ao_led_toggle(AO_LED_TRNG_READ|AO_LED_TRNG_WRITE);
usb_buf_id = 1-usb_buf_id;
}
ao_led_off(AO_LED_TRNG_READ|AO_LED_TRNG_WRITE);
flush();
}
static void
ao_trng_word(void)
{
printf("%d\n", fetch16(0));
}
static void
ao_status(void)
{
if (ao_failed)
printf("FAILED\n");
else
printf("NOMINAL\n");
}
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_blink_green_toggle, "G\0Toggle green LED blinking" },
{ ao_status, "s\0show status" },
{ ao_simulate_failure, "z\0simulate failure" },
{ 0, NULL },
};
void
ao_trng_init(void)
{
ao_add_task(&ao_blink_red_task, ao_blink_red, "blink_red");
ao_add_task(&ao_blink_green_task, ao_blink_green, "blink_green");
ao_cmd_register(ao_trng_cmds);
}
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