tree d67682d6f5d2af7d1ee7f3574c3253dc44410185
parent 0cb6664d29f9172fad65e6771f7aa6b0867b1920
author Fabio Utzig <utzig@apache.org> 1629281576 -0300
committer Fabio Utzig <utzig@apache.org> 1629316157 -0300

trng: kinetis: update TRNG to be interrupt driven

When TRNG HW (not RNGA) is present, it can be used in an interrupt
driven manner, where interrupts are generated for data available or on
errors. With this commit the poller task is updated so it only runs when
woken by an interrupt instead of polling constantly to fill in the
cache. This fixes issues with task starvation, since the poller task is
very high priority and the TRNG is very slow in the standard
configuration.

A new syscfg was added to allow faster generation of entropy by
changing the value of `KINETIS_TRNG_ENTROPY_DELAY`.

This commit also refactors the TRNG queue to be simpler and better
abstracted.

PS: the commit does not touch the functionality of RNGA based HW (eg
K64F).

Signed-off-by: Fabio Utzig <utzig@apache.org>