Merge pull request #8029 from OpenNuvoton/nuvoton_fix_lpticker_wrapper

Fix issues with LowPowerTickerWrapper
ARMmbed · Sep 19, 2018 · 962273c · 962273c
2 parents 3d94fb8 + 5b90b4c
commit 962273c
Showing 1 changed file with 12 additions and 3 deletions.
diff --git a/hal/LowPowerTickerWrapper.cpp b/hal/LowPowerTickerWrapper.cpp
@@ -207,7 +207,14 @@ void LowPowerTickerWrapper::_timeout_handler()
  _pending_timeout = false;
 
  timestamp_t current = _intf->read();
- if (_ticker_match_interval_passed(_last_set_interrupt, current, _cur_match_time)) {
+ /* Add extra check for '_last_set_interrupt == _cur_match_time'
+ * 
+ * When '_last_set_interrupt == _cur_match_time', _ticker_match_interval_passed sees it as
+ * one-round interval rather than just-pass, so add extra check for it. In rare cases, we
+ * may trap in _timeout_handler/_schedule_match loop. This check can break it.
+ */
+ if ((_last_set_interrupt == _cur_match_time) ||
+ _ticker_match_interval_passed(_last_set_interrupt, current, _cur_match_time)) {
  _intf->fire_interrupt();
  } else {
  _schedule_match(current);
@@ -223,7 +230,9 @@ bool LowPowerTickerWrapper::_match_check(timestamp_t current)
  if (!_pending_match) {
  return false;
  }
- return _ticker_match_interval_passed(_last_set_interrupt, current, _cur_match_time);
+ /* Add extra check for '_last_set_interrupt == _cur_match_time' as above */
+ return (_last_set_interrupt == _cur_match_time) ||
+ _ticker_match_interval_passed(_last_set_interrupt, current, _cur_match_time);
 }
 
 uint32_t LowPowerTickerWrapper::_lp_ticks_to_us(uint32_t ticks)
@@ -245,7 +254,7 @@ void LowPowerTickerWrapper::_schedule_match(timestamp_t current)
  }
  }
 
- uint32_t cycles_until_match = (_cur_match_time - _last_set_interrupt) & _mask;
+ uint32_t cycles_until_match = (_cur_match_time - current) & _mask;
  bool too_close = cycles_until_match < _min_count_until_match;
 
  if (!_set_interrupt_allowed) {