On Wednesday, May 25, 2011, Wolfgang Denk <w...@denx.de> wrote: > Dear Graeme Russ, > > In message <4ddcf926.1050...@gmail.com> you wrote: >> >> Many platforms have a hardware counter which is incremented without >> assistance from software - not by an ISR, nothing (I mentioned this before, >> but I can't track down the exact email) - THIS is the tick counter returned >> by get_ticks() which the prescaler uses to update the timer when you either: >> >> - Explicitly call get_timer() >> - Call the prescaler from an ISR >> >> The thing is, I have now highlighted that relying on interrupts to keep >> get_timer() working is a really bad idea - We have no way of stopping >> anyone from calling disable_interrupts() before using the timer > > There may be code which doe snot call get_timer() for _long_ times. > And somebody disables interrupts. What's then? > We're hosed, but at least we are one better than relying on interrupts alone ;)
And what about platforms that do not support interrupts? Are you mandating that get_timer() MUST always be supported by a timer updated by an ISR? Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
