Mike, On Tue, May 24, 2011 at 2:24 PM, Mike Frysinger <vap...@gentoo.org> wrote: > rather than inventing our own set of terms, how about piggybacking what Linux > has already done ? they have "cycle counters" and "timer counters" (which > bubble up into "clock sources", but i dont think we need those).
I only put the terms in to clarify them within the scope of the document to avoid the inevitable 'but that means x' arguments ;) > further, Linux probably already has implementations we can steal for the arch- > specific "cycle counters", and the common code which takes care of scaling > those into actual measurements of time. Maybe - but I think the Linux implementation might be a bit too heavy handed - We only need a very lightweight, simple implementation. Despite the appearance of my write-up, the suggested implementation is very simple: - A common software prescaler in /lib/ (not needed if hardware provides an exact 1ms period counter) - Arch specific implementation of tick counter (already there) - Arch specific hook into prescaler (not needed if tick counter has a 'long enough' roll-over period or is 1ms, otherwise a tiny ISR which simply calls the prescaler) Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
