Re: [PATCH 3/3] MIPS: DMA: Add plat_extra_sync_for_cpu()

[Sergei Shtylyov]

Hello.

On 09-09-2010 3:02, Kevin Cernekee wrote:

> On noncoherent processors with a readahead cache, an extra platform-
> specific invalidation is required during the dma_sync_*_for_cpu()
> operations to keep drivers from seeing stale prefetched data.

> Signed-off-by: Kevin Cernekee<cernekee@xxxxxxxxx>
[...]
> diff --git a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> index 17d5794..8192683 100644
> --- a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> @@ -52,6 +52,19 @@ static inline void plat_extra_sync_for_device(struct device *dev)
>   	mb();
>   }
>
> +static inline void plat_extra_sync_for_cpu(struct device *dev,
> +	dma_addr_t dma_handle, unsigned long offset, size_t size,
> +	enum dma_data_direction direction)
> +{
> +	return;

   Why not just empty function bodies?

WBR, Sergei
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