On 06/18/2012 07:13 AM, R, Sricharan wrote: > Hi Tom, > > On Fri, Jun 15, 2012 at 8:50 PM, Tom Rini <tr...@ti.com> wrote: >> On 06/15/2012 08:18 AM, R, Sricharan wrote: >>> Hi, >>> [snip..] >>>>>>> If it is a problem with unaligned regions, then that is the only >>>>>>> thing to be fixed >>>>>>> right ?. Just trying to understand why this change is required ? >>>>>> >>>>>> The problem is that within the USB/network/filesystem stacks we have a >>>>>> lot of not cache safe alignments apparently. Without this every '#' of >>>>>> a tftp gives a screen full of error printfs. So tftp'ing a kernel takes >>>>>> minutes, not seconds, to complete. >>>>>> >>>>> Ok,but when buffers are not aligned >>>>> isn't that you are going to have coherency problems ? >>>> >>>> Exactly. USB requires dcache to be turned off today. With it turned >>>> off it spams these messages making tftp to an aligned address take >>>> minutes because the console is busy printing all of these messages about >>>> flushes it didn't need to do. The alternative is to build >>>> omap4/omap5/etc with dcache disabled or USB disabled. >>>> >>> Ok, but who is calling cache maintenance in your case after >>> turning off caches ? >> >> The USB stack currently. > > Ok, in that case if > 1) Alignment issue has to be fixed USB stack, (or)
This is the correct, long term solution. > 2) Better to turn off caches when say USB-EHCI is enabled ? Doing that is what showed the issue to start with. Running 'dcache off' doesn't turn off attempted cache flushing. > (or) > > 3) Turn of caches until cache library is fixed so that > we will not require any maintenance after turning it off. > ( I will work on this some time, this week) This is also a good thing. It just needs to make sure attempted flushes don't spam the console, when cache is off :) > I am not sure which one to do, but definitely we should not > prevent it from executing as in the above patch. This may > lead to other issues. OK. I'll see how badly boot time goes up when dcache is off to start with on a few boards. -- Tom _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot