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

Daniel Walker dwalker at codeaurora.org
Mon Jan 11 19:28:53 EST 2010


On Mon, 2010-01-11 at 23:33 +0000, Russell King - ARM Linux wrote:
> 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.

Do you have any hints on who's doing the development ?

Daniel




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