Hi, On Thu, Sep 15, 2011 at 10:41 AM, Mike Frysinger <[email protected]> wrote: > On Thursday, September 15, 2011 13:30:09 Albert ARIBAUD wrote: >> I agree on the need and interest to support cache. I disagree on the way >> to get there. Turning cache off indiscriminately and hoping that board >> developers/maintainer turn their caches off will only lead to U-Boot >> failing in interesting ways and cluttering the mailing list with >> requests for help until someone figures out the cache is the culprit. > > if code only works when cache is turned on, that usually means the code is > broken and is missing appropriate barriers/flushes. turning cache on doesnt > fix the underlying issue, it ignores it. ive seen this in the past with > Blackfin parts where our testers will do some operation with caches on, and > then try things with caches off, and trigger bugs in drivers due to missing > syncs but things work due to implicit timings with cache on. > >> We have started outlining a solution (weak generic cache (non-)functions >> in arch/arm/lib/cache.c which only warn about cache not being enabled, >> and cpu/SoC/board specific versions that enable cache where it works. > > which is causing the copy & paste i'm whining about > >> We also have started discussing minimizing cache code copy -- admittedly >> spinned off a patch submission discussion, so it may have been missed, >> and I will repost the RFC in its own thread -- whereby the cache >> functions would be defined as weak function in the lib, and could be >> overriden by ISA-level function, which themselves could be overriden by >> CPU-level functions, and SoC (or even board) level functions could >> override them all. > > i guess i did miss it. it doesnt matter to me how we get to the ultimate > destination ({I,D}CACHE_ON/etc...), just that ultimately the crappy/dead SoC's > are not bogging down the modern/maintained ones by forcing the common > implementation to suck. > -mike >
Right, I am going to resubmit this patch in the arch/arm/cpu/armv7/tegra2 directory and see how that looks. Regards, Simon _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
