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

[Tom Rini]

On 06/15/2012 07:25 AM, Marek Vasut wrote:
> Dear Tom Rini,
> 
>> On 06/14/2012 10:48 PM, R, Sricharan wrote:
>>> Hi Tom,
>>>
>>> On Fri, Jun 15, 2012 at 12:31 AM, Tom Rini <trini at ti.com> wrote:
>>>> If we are built with D-CACHE enabled but have run 'dcache off' and then
>>>> attempt to flush unaligned regions we spam the console with problems
>>>> that aren't true (as the cache was off).
>>>>
>>>   Today we do cache maintenance operations after the dcache is turned
>>>   off. One example is before jumping to kernel, we try to invalidate the
>>>   caches, in cache turned off state. So with this patch those
>>>   maintenance calls will do nothing, which is not correct.
>>
>> Ah yes,  But, shouldn't we be doing these same operations as part of
>> turning the cache off?
>>
>>>    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.
> 
> I think we should augment uboot to disallow tftp, fatload etc. to cache-
> unaligned address when caches are on ... this'd squash away the need for any 
> shitty bounce buffers right away. Tom, will you be able to implement it, pretty 
> please?

But that's not the problem.  The problem is all of the stuff going on
within the USB/networking stack.

-- 
Tom