[U-Boot] [PATCH 2/4] cache_v7: Check for dcache enablement in dcache flush functions

Tom Rini
2012-06-15T15:20:51Z

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.

--
Tom