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

Thomas Chou thomas at wytron.com.tw
Mon Oct 12 14:55:03 CEST 2015


Hi Marek,

On 10/12/2015 06:32 PM, Marek Vasut wrote:
> Wouldn't invalidate_dcache_range() be enough here ? You don't care about the
> data in the newly allocated area at this point I guess -- either you fill them
> in and then flush, for DMA from CPU to device OR you receive data from device
> to CPU and then you invalidate this buffer again.

No. We cannot use invalidate cache here. This is related to cache design 
of nios2, kind of direct mapped cache.

Best regards,
Thomas


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