[U-Boot] [PATCH v4] nios2: convert dma_alloc_coherent to use malloc_cache_aligned

Albert ARIBAUD
2015-10-19T08:27:00Z

Hello Thomas,

On Mon, 19 Oct 2015 16:18:06 +0800, Thomas Chou <thomas@wytron.com.tw>
wrote:
> Hi Albert,
>
> On 10/19/2015 01:52 PM, Albert ARIBAUD wrote:
> > Not sure I'm getting this, so for my own education: what prevents from
> > invalidating the cache, or IOW, what would happen if it was invalidated
> > at this point rather than flushed?
>
> This is a hardware limitation. The nios2 cpu with 4 bytes dcache line
> size does not support the initda instruction, which is needed to
> invalidate dcache.
>
> Recently we added a check, if the nios2 cpu support initda instruction,
> then we use invalidate_dcache, otherwise we use flush_dcache.

Now I understand. Thanks!

> Best regards,
> Thomas

Amicalement,
--
Albert.