The RTC on TI CC13X2/CC26X2 is a 32 KHz clock for which the minimum
compare delay is 3 ticks. When using it as the system clock, we need
to relax the upper bound to ensure the test succeeds.
Signed-off-by: Vincent Wan <vincent.wan@linaro.org>
Nordic platforms measure ticks in cycles of a 32 KiHz clock for which
the minimum compare delay is 2 ticks. The test assumed an upper bound
of four ticks delay per loop iteration, resulting from alignment at
various layers. This delay is met on Nordic for tick rates at or below
16384, but is too short for the default 32768 Hz tick rate.
Instrumentation confirms that the usleep test loop body on Nordic at 32
KiHz ticks takes 3 ticks as the optimum delay, only when a debug probe
is active. In other circumstances it can take either 5 or 6 ticks,
depending on timer alignment and stability.
Relax the upper bound for platforms using this system timer at the
highest rate.
Closes#17965.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
The logic about minimal sleep sizes due to "tick" aliasing was
correct, but drivers also have similar behavior with "cycle" aliasing
too. When cycles are 3-4 orders of magnitude faster than ticks, it's
undetectable noise. But now on nRF they're exactly the same and we
need to correct for that, essentially doubling the number of ticks a
usleep() might wait for.
The logic here was simply too strict, basically. Fast tick rates
can't guarantee what the test promised.
Note that this relaxes the test bounds on the other side of the
equation too: it's no longer an error to usleep() for only one tick
(i.e. an improved sleep/timeout implementation no longer gets detected
as a test failure).
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Test that k_usleep() allows sleep durations near the limit of what
the platform's tick rate will allow.
Signed-off-by: Charles E. Youse <charles.youse@intel.com>
