ztimer's machinery depends on figuring out if a timer is currently set
or not. It does that using _is_set(), which is also exposed as
ztimer_is_set().
Now when a timer expired and got taken of the timer queue using
_now_next(), the `next` pointer wasn't unset. This caused _is_set() to
wrongly return `true` for that timer.
Internally in ztimer, this didn't cause breakage, just an unnecessary
iteration of the timer queue by _delete_timer_from_list().
But this also broke the public ztimer_is_set().
This commit fixes the issue by correctly NULLing the timer's `next`
pointer when the timer triggers.
MSEC and SEC are now usable on TIMER(0) without having USEC
pm is configured by used hardware
OLD configuration values are translated for backward compatibility
prefer rtt for ZTIMER_SEC
avoid doing partial ztimer setup if auto_init_ztimer is disabled
before this patch some const pointers might have been definend to values
that a user who disables auto_init for ztimer does not like.
wire up ZTIMER_SEC to the existing RTC backend, or RTT backend, or periph_timer
backend (in this order of preference).
Update sys/ztimer/auto_init.c
Co-authored-by: Leandro Lanzieri <leandro.lanzieri@haw-hamburg.de>
Replace direct accesses to sched_active_thread and sched_active_pid with
the helper functions thread_getpid() and thread_get_active(). This serves
two purposes:
1. It makes accidental writes to those variable from outside core less likely.
2. Casting off the volatile qualifier is now well contained to those two
functions
When using convert_frac to slow down a timer, the extension machinery is
used to prevent converting values that would be larger than, after
conversion, 2**32. In order to calculate the maximum value, UINT32_MAX
is converted.
Previously, this was mistakenly converted by multiplying with the
fraction used to scale up a value. E.g., when using convert_frac to
slow down a 1us timer to provide a 1ms timer, UINT32_MAX was multiplied
by 1000. As the result is used % UINT32_MAX, this lead to a wrong value
close to UINT32_MAX, as ((UINT32_MAX * N) % UINT32_MAX = (UINT32_MAX - N - 1)).
This PR fixes the calculation so max_value is determined by multiplying
with the fraction used to scale down a value.
