2 * Copyright © 2015 Keith Packard <keithp@keithp.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
19 #include <ao_adc_fast.h>
21 #include <ao_trng_send.h>
25 static uint8_t trng_running;
26 static AO_TICK_TYPE trng_power_time;
29 ao_trng_send_raw(uint16_t *buf)
33 uint16_t *rnd = (uint16_t *) ao_adc_ring;
35 t = ao_adc_get(AO_USB_IN_SIZE>>1); /* one 16-bit value per two output bytes */
36 for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
38 t = (t + 1) & (AO_ADC_RING_SIZE - 1);
43 ao_trng_send_cooked(uint16_t *buf)
47 uint32_t *rnd = (uint32_t *) ao_adc_ring;
49 t = ao_adc_get(AO_USB_IN_SIZE) >> 1; /* two 16-bit values per two output bytes */
50 for (i = 0; i < AO_USB_IN_SIZE / sizeof (uint16_t); i++) {
51 *buf++ = ao_crc_in_32_out_16(rnd[t]);
52 t = (t + 1) & ((AO_ADC_RING_SIZE>>1) - 1);
59 return !ao_gpio_get(AO_RAW_PORT, AO_RAW_BIT, AO_RAW_PIN);
65 static uint16_t *buffer[2];
69 buffer[0] = ao_usb_alloc();
70 buffer[1] = ao_usb_alloc();
77 #ifdef AO_TRNG_ENABLE_PORT
78 ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
80 trng_power_time = ao_time();
88 delay = trng_power_time + AO_MS_TO_TICKS(100) - ao_time();
89 if (delay > AO_MS_TO_TICKS(100))
90 delay = AO_MS_TO_TICKS(100);
92 /* Delay long enough for the HV power supply
93 * to stabilize so that the first bits we read
94 * aren't of poor quality
100 ao_led_on(AO_LED_TRNG_RAW);
101 ao_trng_send_raw(buffer[usb_buf_id]);
102 ao_led_off(AO_LED_TRNG_RAW);
104 ao_led_on(AO_LED_TRNG_COOKED);
105 ao_trng_send_cooked(buffer[usb_buf_id]);
106 ao_led_off(AO_LED_TRNG_COOKED);
108 ao_adc_ack(AO_USB_IN_SIZE);
109 ao_usb_write(buffer[usb_buf_id], AO_USB_IN_SIZE);
110 usb_buf_id = 1-usb_buf_id;
114 static struct ao_task ao_trng_send_task;
116 #if AO_POWER_MANAGEMENT
118 static void ao_trng_suspend(void *arg)
121 #ifdef AO_TRNG_ENABLE_PORT
122 ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 0);
124 trng_running = FALSE;
127 static void ao_trng_resume(void *arg)
130 #ifdef AO_TRNG_ENABLE_PORT
131 ao_gpio_set(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 1);
133 trng_power_time = ao_time();
136 static struct ao_power ao_trng_power = {
137 .suspend = ao_trng_suspend,
138 .resume = ao_trng_resume
144 ao_trng_send_init(void)
146 #ifdef AO_TRNG_ENABLE_PORT
147 ao_enable_output(AO_TRNG_ENABLE_PORT, AO_TRNG_ENABLE_BIT, AO_TRNG_ENABLE_PIN, 0);
148 ao_power_register(&ao_trng_power);
150 ao_enable_input(AO_RAW_PORT, AO_RAW_BIT, AO_EXTI_MODE_PULL_UP);
151 ao_add_task(&ao_trng_send_task, ao_trng_send, "trng_send");