On Wed, Sep 23, 2020 at 02:48:18PM +0200, Wolfgang Denk wrote: > Dear Rasmus, > > In message <afea5640-9d95-bf92-316a-0d674a512...@prevas.dk> you wrote: > > On 04/06/2020 12.31, Stefan Roese wrote: > > > On 04.06.20 11:30, Rasmus Villemoes wrote: > > >> Calling WATCHDOG_RESET for each and every cache line is overkill. > > >> > > >> In our case, the kernel image is a little over 7MB, and the almost > > >> 500000 calls of WATCHDOG_RESET() adds about one second to the > > >> boottime. > > >> > > >> I very highly doubt there's any real hardware where flushing 64K > > >> from cache to memory takes more than a few milliseconds, so this > > >> should be completely safe. Since it reduces the number of > > Maybe it is, maybe it is not. I remember boards where the watchdog > trigger had to happen in pretty tight intervals, something like min > 20, max 60 milliseconds. > > > >> + if ((addr & (SZ_64K - 1)) == 0) > > In any case, please write readable code. The use of SZ_ here is not > a good idea. Also, you might want to make the actual parameter > configurable, so boards with specific timing requirements can adjust > this as needed.
We should add a comment somewhere here to match the commit message, but since we're flushing on 64K chunks, SZ_64K makes sense. If we make it build-time configurable then it's not a concern. I assume we don't want to make this run time configurable. -- Tom
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