[linuxsh-dev] Running TMU1

[Jeremy S. <js...@mv...>]

I'd like to include the following timer.c patch to set up TMU1 as a
free-running timer for timestamp or instrumentation purposes (or maybe a
future port of hi-res timers to the SH kernel).  This'll be in our
distribution under ifdefs specific to features that use it; in this patch
it's just under CONFIG_START_TMU1 since that seemed more general (could be
turned on by features needing it).  [I've also attached a modified
preem_latency.h file, just as an example of how it'd be used; it seems
simpler than what's currently in the preempt_stats patch for SH.]

To Masahiro Abe: is this usage similar enough to your usage in RT-Linux
that it doesn't conflict?  Would it help to
put the startup code under a conditional check on whether the timer has
already been activated?

Last month I sent out a query about this, and one question I had was that
even TMU0 seems to be running faster
than the specs allow, and I've been running both TMU1 and TMU0 at the same
speed w/o apparent problems yet...
again, I'm assuming that aspect of the spec is incorrect (irrelvant to
SH3/SH4) but if that's a bad assumption
please let me know!

Any objections to the timer.c change?

Thanks,
  --Jeremy Siegel