[U-Boot] [PATCH] nios2: convert cache flush to use dm cpu data

Marek Vasut
2015-10-10T18:12:43Z

On Saturday, October 10, 2015 at 07:55:45 AM, Thomas Chou wrote:
> Hi Marek,

Hi,

> On 10/09/2015 10:42 PM, Marek Vasut wrote:
> >> In nios2, we don't skip the flushing when the inputs are not aligned
> >> like that of arm926ejs. We always flush all cache lines in the range,
> >> even if a single byte to flush is in request. So the inputs are rounded
> >> to get the lower and upper cache lines range inside the cache flush
> >> functions. The caller need not be aware of the detail.
> >
> > This is incorrect and all the places which produce these unaligned cache
> > operations must be fixed.
>
> I take a look into the cache flush operations in every arch of u-boot.
> It turns out that the arm926ejs is the only platform that does such
> cache line range check and skip. All other ARM and all other arch don't.

Yes, everyone else doesn't do the checks and if there is unaligned cache
flush/invalidation, that platform also suffers from various obscure and hard
to debug errors. I submitted patch to add the same check for ARMv7, but it
didn't receive attention :-( I should repost it I guess.

> And the cache flush in Linux don't.

Because the buffers there are always correctly aligned during allocation.

Best regards,
Marek Vasut