[U-Boot] [PATCH] OMAP3: workaround for ARM Cortex-A8 erratum 725233

[Siarhei Siamashka <siarhei.siamashka@gmail.com>]

On Sunday 07 February 2010, Tom wrote:
> Siarhei Siamashka wrote:
> > 725233: PLD instructions executed with PLD data forwarding
> > enabled can result in a processor deadlock
> >
> > Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
>
> Please add a detailed comment on the errata.

The short summary is pretty much complete (PLD data forwarding is not working
correctly and needs to be turned off to prevent problems). Though it really
makes sense to add that:
1. only r1pX revisions of Cortex-A8 are affected
2. performance impact is practically non-existant

The detailed description of this erratum is available in the official
Cortex-A8 errata list. I'm not sure about directly copying full erratum
description text here. Anyway, this workaround would be better submitted
by somebody TI. I'm just "guilty" of triggering this deadlock with some
ARM NEON optimizations from pixman library, so feel a bit of responsibility
for it too.

> Also looks like this jumping to ROM code.
> Can this be done without a ROM code call ?

I just added it to the part of code which is already doing similar things
(sets L1NEON and other bits from AUXCR with some icky looking assembly via
ROM code call). Most likely it can be also done in some other way.

-- 
Best regards,
Siarhei Samashka