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/*
* Watchdog
*
* Copyright (c) 2018-2020 Michael Buesch <m@bues.ch>
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "compat.h"
#include "debug.h"
#include "watchdog.h"
#include "main.h"
#include "util.h"
#include "arithmetic.h"
#include "battery.h"
static struct {
uint8_t state;
uint8_t transition_delay;
uint8_t active_wdto;
bool standby;
} watchdog;
static const __flash struct {
uint8_t wdto;
uint16_t ms;
} watchdog_timeouts[] = {
{ .wdto = WDTO_60MS, .ms = 60, }, /* First normal state */
{ .wdto = WDTO_120MS, .ms = 120, },
{ .wdto = WDTO_250MS, .ms = 250, },
{ .wdto = WDTO_500MS, .ms = 500, }, /* Last normal state */
/* ----------------------------------- */
{ .wdto = WDTO_2S, .ms = 2000, }, /* Battery-low state */
};
#define WATCHDOG_FIRST_NORMAL_STATE 0u
#define WATCHDOG_INIT_STATE (WATCHDOG_FIRST_NORMAL_STATE + 1u)
#define WATCHDOG_LAST_NORMAL_STATE (ARRAY_SIZE(watchdog_timeouts) - 2u)
#define WATCHDOG_BATCRIT_STATE (ARRAY_SIZE(watchdog_timeouts) - 1u)
/* Watchdog state transition delay */
#define WATCHDOG_TRANS_DELAY 100 /* Watchdog cycles */
/* Get the currently active watchdog interrupt trigger interval, in milliseconds. */
uint16_t watchdog_interval_ms(void)
{
if (USE_WATCHDOG_IRQ)
return watchdog_timeouts[watchdog.state].ms;
return watchdog_timeouts[WATCHDOG_INIT_STATE].ms;
}
/* Reconfigure the watchdog interval.
* Interrupts shall be disabled before calling this function. */
static void watchdog_reconfigure(void)
{
uint8_t wdto;
if (USE_DEEP_SLEEP) {
if (battery_voltage_is_critical()) {
/* If the battery voltage is critical,
* enforce the slowest watchdog interval. */
watchdog.state = WATCHDOG_BATCRIT_STATE;
watchdog.transition_delay = WATCHDOG_TRANS_DELAY;
} else if (!watchdog.standby) {
/* If the system is fully running,
* enforce the fastest watchdog interval. */
watchdog.state = WATCHDOG_FIRST_NORMAL_STATE;
watchdog.transition_delay = WATCHDOG_TRANS_DELAY;
} else {
/* Limit the state to the normal range. */
watchdog.state = min(watchdog.state,
WATCHDOG_LAST_NORMAL_STATE);
}
/* Program the hardware, if required. */
wdto = watchdog_timeouts[watchdog.state].wdto;
if (wdto != watchdog.active_wdto) {
watchdog.active_wdto = wdto;
wdt_setup(wdto, true, USE_WATCHDOG_IRQ);
}
}
}
/* Enable/disable watchdog standby state.
* Interrupts shall be disabled before calling this function. */
void watchdog_set_standby(bool standby)
{
if (USE_DEEP_SLEEP) {
watchdog.standby = standby;
watchdog_reconfigure();
}
}
/* Watchdog timer interrupt service routine. */
#if USE_WATCHDOG_IRQ
ISR(WDT_vect)
{
memory_barrier();
// dprintf("WDT_vect\r\n");
/* Notify the system. */
system_handle_watchdog_interrupt();
if (USE_DEEP_SLEEP) {
/* Go to the next watchdog interval state,
* if the system is in standby. */
if (watchdog.standby) {
watchdog.transition_delay = sub_sat_u8(watchdog.transition_delay, 1u);
if (watchdog.transition_delay == 0u) {
watchdog.transition_delay = WATCHDOG_TRANS_DELAY;
if (watchdog.state < WATCHDOG_LAST_NORMAL_STATE)
watchdog.state++;
}
}
/* Configure the new interval, if required. */
watchdog_reconfigure();
}
memory_barrier();
WDTCR |= (1 << WDIE);
memory_barrier();
}
#endif /* USE_WATCHDOG_IRQ */
/* Early watchdog timer initialization. */
static void section_init3 wdt_early_init(void)
{
/* Clear WDRF (and all other reset info bits). */
MCUSR = 0;
/* Enable the watchdog. */
watchdog.active_wdto = watchdog_timeouts[WATCHDOG_INIT_STATE].wdto;
wdt_setup(watchdog_timeouts[WATCHDOG_INIT_STATE].wdto,
true, USE_WATCHDOG_IRQ);
/* Enable watchdog interrupt for wake up from deep sleep. */
if (USE_DEEP_SLEEP) {
watchdog.state = WATCHDOG_INIT_STATE;
watchdog.transition_delay = WATCHDOG_TRANS_DELAY;
}
}
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