[U-Boot] [PATCH v2] ARM926ejs: Add routines to invalidate D-Cache

[Albert ARIBAUD]

Le 08/08/2011 10:24, Aneesh V a écrit :
> Hi Albert,
>
> On Sunday 07 August 2011 12:25 PM, Albert ARIBAUD wrote:
>> Hi Aneesh,
>>
>> (cutting quotation for readability)
>>
>> Le 05/08/2011 16:59, Aneesh V a écrit :
>>> Hi Albert,
>>
>>> I don't dispute that having buffers aligned is the ideal scenario. The
>>> question is about error-handling the situation when this requirement is
>>> not met.
>>
>> I understand what you're trying to achieve in this respect, that is,
>> make the code as correct as it can be under unspecified conditions. I
>> believe we are differing in how we construe 'as correct as it can be':
>> you want to make the implementation of the called function as correct as
>> it can be' at the expense of introducing a non-intuitive behavior (flush
>> while invalidating), while I prefer the overall system to be as correct
>> as it can be by 'doing exactly what it says on the tin', i.e.
>> invalidating only.
>
> I understand your point of view now. I shall update my cache fix series
> to invalidate only the aligned part of the buffer and to print a big
> warning when the buffer is not aligned.

Thanks Aneesh.

Another point I raised with Hong Xu's patch: for range-limited 
operations, in case of a misalignment, why not try to *reduce* to 
aligned addresses rather than *expand* it? Moving start up to the next 
cache line boundary, and moving stop down, would still cause an 
imperfect situation (can't help it anyway) but it would not affect third 
party data any more, only the data which the cache range operation was 
supposed to affect.

What do you (and others) think?

> best regards,
> Aneesh

Amicalement,
-- 
Albert.