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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_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);
}
static struct ao_task ao_blink_red_task;
static int8_t ao_failed = -1; /* -1 need POST, 0 NOMINAL, 1 FAILED */
/* 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_trng_failure(void)
{
ao_failed = 1;
ao_wakeup(&ao_failed);
}
static void
ao_trng_fetch(uint32_t kbytes)
{
static uint16_t *buffer[2];
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();
buffer[1] = ao_usb_alloc();
if (!buffer[0])
return;
}
usb_buf_id = 0;
count = kbytes * (1024/AO_USB_IN_SIZE);
ao_crc_reset();
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];
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);
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_fetch_cmd(void)
{
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_trng_status(void)
{
if (ao_failed)
printf("FAILED\n");
else
printf("NOMINAL\n");
}
static const struct ao_cmds ao_trng_cmds[] = {
{ 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_trng_status, "s\0Show status" },
{ ao_trng_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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