[U-Boot] [RFC/PATCH] davinci: disable dcache on boards with EMAC

[Tom Rini]

On Sun, Nov 27, 2011 at 11:43 AM, Wolfgang Denk <wd at denx.de> wrote:
> Dear Tom Rini,
>
> In message <CA+M6bX=F0s3yuxZDnR+x0adi+eiE2dHW2qxZoDie_U7xSRkWMQ at mail.gmail.com> you wrote:
>>
>> > For example, booting from NAND is probably MUCH faster with caches on.
>> > Why should we make this slower than necessary?
>>
>> To encourage someone with the domain knowledge to finish cache support
>> for the processor?
>
> That would be unfair.  If you want to push for fixes, then push the
> where the problems are coming from.  If it's the EMAC driver, then
> let's disable the EMAC driver until it gets fixed.

Would this series, but with removing emac from the davinci config
files instead, be OK then?

> Alternatively, let's add enough fixes to make it compile, and have
> people switch cahces off before using the driver.

This was the first iteration, and was NAK'd by someone else (I don't
recall who right now).

>> > We cannot _compile_ the driver?  That's even worse and needs to be
>> > fixed.
>>
>> That's what this patch was doing, by disabling the cache so it would
>> build.  To be clear, today it builds but doesn't work with cache on.
>
> NO, it is NOT a fix. It is a dirty workaround that makes everybody
> suffer, even if he is not interested in this driver at all.
>
> Rather disable the driver in the config files.
>
>
> Hm... actually I don't understand you.  First you write: "we can't
> compile the driver", then you write "it builds but doesn't work with
> cache on".

I was unclear, sorry.  Let me summarize:
- Today, the driver builds for davinci platforms, but anecdotal
evidence says it doesn't function without 'dc off'.
- With this series, fully, davinci builds, and works, because dcache
is off, and am35x now has ethernet, with dcache on.
- With this series, minus this single part, davinci fails to link with
this driver enabled because of missing cache functions.

-- 
Tom