[RFC 16/18] arm: msm: add arch_has_speculative_dfetch()

[Russell King - ARM Linux]

On Mon, Jan 11, 2010 at 02:47:35PM -0800, Daniel Walker wrote:
> From: Steve Muckle <smuckle at quicinc.com>
> 
> The Scorpion CPU speculatively reads data into the cache. This
> may occur while a region of memory is being written via DMA, so
> that region must be invalidated when it is brought under CPU
> control after the DMA transaction finishes, assuming the DMA
> was either bidirectional or from the device.
> 
> Currently both a clean and invalidate are being done for
> DMA_BIDIRECTIONAL in dma_unmap_single. Only an invalidate should be
> required here. There are drivers that currently rely on the clean
> however so this will be removed when those drivers are updated.

NAK.  There are patches around (and potentially queued) for the next
merge window which properly address this.