--- /dev/null
+/*
+ * 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 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;
+ uint16_t t;
+ uint32_t *rnd = (uint32_t *) ao_adc_ring;
+
+ 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--) {
+ 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[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);
+ 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 const struct ao_cmds ao_trng_cmds[] = {
+ { ao_trng_fetch, "f <kbytes>\0Fetch a block of numbers" },
+ { 0, NULL },
+};
+
+void
+ao_trng_init(void)
+{
+ ao_cmd_register(ao_trng_cmds);
+}