On Mon, 2011-04-04 at 22:08 +0200, Linus Walleij wrote: > 2011/4/4 Marc Zyngier <Marc.Zyngier@xxxxxxx>: > > On Mon, 2011-04-04 at 14:31 +0100, Russell King - ARM Linux wrote: > >> > >> If ARM are going to architect a set of timers into the hardware, let's > >> make sure that all such hardware has them so we can dig ourselves out > >> of this crappy mess that we find ourselves in today. > > > > As far as I know, A15 always has a set of generic timers. > > > > It may be that they are not available (frequency not programmed into the > > CNTFREQ register), or that someone decided to use a better alternative > > (for some particular interpretation of "better"). > > I guess this thing is inside that A15 core? > > First, what happens the day any vendors start making SoCs on this is > they turn the A15 core off whenever it is not used, loosing all state > including this timer, I believe. The main counter is located in an ALWAYS_ON power domain, and should keep going whatever happens in the system. [...] > Second, have you taken into account the effect of changing the > frequency of the A15 core, which is something every vendor also > does, as you know Colin Cross already has a patch pending > for that on the TWD localtimer which has not yet reached > the kernel. (Or is A15 fixed frequency? Forgive my ignorance...) Fixed frequency, with a minimal roll-over time of 40 years. M. -- Reality is an implementation detail. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
