watchdog.c

#include <stdint.h>
#include <dev/watchdog.h>
#include <sys/clock.h>
#include <core/pm.h>
#include <core/mwork.h>
#include <core/irq-prio.h>
#include <nrf52.h>
#include <hal/nrf_wdt.h>

#define WATCHDOG_TIMEOUT_S      4

struct watchdog_state_t
{
  unsigned dt;
  struct mwork_t work;
};

static void watchdog_work_cb(struct mwork_t *work);

static struct watchdog_state_t watchdog_state;

void watchdog_init(void)
{
  nrf_wdt_behaviour_set(NRF_WDT_BEHAVIOUR_PAUSE_SLEEP_HALT);
  nrf_wdt_reload_value_set(32768UL * WATCHDOG_TIMEOUT_S - 1);
  nrf_wdt_reload_request_enable(0);
  nrf_wdt_int_enable(NRF_WDT_INT_TIMEOUT_MASK);
  watchdog_state.work = MWORK_INIT_TYPED(watchdog_state.work, watchdog_work_cb);

  sd_nvic_ClearPendingIRQ(WDT_IRQn);
  sd_nvic_SetPriority(WDT_IRQn, EVE_IRQ_PRIORITY_HIGH);
  sd_nvic_EnableIRQ(WDT_IRQn);
}

void watchdog_start(void)
{
  nrf_wdt_task_trigger(NRF_WDT_TASK_START);
}

void watchdog_periodic(void)
{
  nrf_wdt_reload_request_set(0);
  if (watchdog_state.dt)
  {
    SWINT_AUTO_LOCK();
    watchdog_state.work.at = mwork_now() + watchdog_state.dt;
    mwork_schedule(&watchdog_state.work);
  }
}

extern void watchdog_stop_should_never_be_called(void);
void watchdog_stop(void)
{
  watchdog_stop_should_never_be_called();
}

void watchdog_reboot(void)
{
  /* Loop until reboot by wdog */
  watchdog_init();
  watchdog_start();
  __disable_irq();
  while(1);
}

void watchdog_keepalive(uint32_t duty)
{
  watchdog_state.dt = MS_TO_TICKS(1000 * WATCHDOG_TIMEOUT_S * 3 / 4) * duty;
  if (duty)
  {
    SWINT_AUTO_LOCK();
    watchdog_state.work.at = mwork_now() + watchdog_state.dt;
    mwork_schedule(&watchdog_state.work);
  }
  else
  {
    mwork_cancel(&watchdog_state.work);
  }
}

static void watchdog_work_cb(struct mwork_t *work)
{
  pm_wakeup();
}

void WDT_IRQHandler(void) __attribute__((section(".text"),interrupt));
void WDT_IRQHandler(void)
{
  __BKPT(0);
}