Subject: clocks on mips
To: None <,,>
From: Garrett D'Amore <>
List: port-mips
Date: 09/08/2006 09:02:13
I've been looking at arc.

It appears that all arc systems have a MIPS 3 clock and can handle clock
interrupts on CP0 counter.  I think this is probably also true of
hpcmips.  For pmax and company, it is probably true for _some_ models.

I'd like to recommend the following:

1) convert those models that can do it to common mips3 clock code in
mips/mips/mips3_clock.c, modulo the following comments

2) this means in the short term, loss of statclock.  i propose that the
statclock be handled by the external clocks (whatever are present) when
they exist.  i.e. I'm suggesting that the statclock timer be the
"optional" clock, and that the mips3_cp0_clock always be used. 
statclock/stathz, etc. should be set up by the MD code.

3) this probably means cleaning up mips3_clock.c somewhat -- the
statclock needs to move out of it, and the delay() needs to rename to

4) for systems that can just use mips3_delay as is, I would use a weak
symbol alias so that at link time delay() is resolved to mips3_delay.

5) I'd like to rename cpu_initclocks() to mips3_initclocks() and weak
alias it as well.

6) I'd like to move the resulting mips3_initclocks() and
mips3_clockintr() into a new file, mips3_hardclock.c or
mips3_clockintr.c, so that ports which for some reason can't use these
(ews4800mips?) don't have to carry the baggage, but can still use the
rest of the code in mips3_clock.c


Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191