[U-Boot] [PATCH v4] nios2: convert dma_alloc_coherent to use malloc_cache_aligned
Thomas Chou
thomas at wytron.com.tw
Mon Oct 19 10:18:06 CEST 2015
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.
Best regards,
Thomas
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