[RFC 16/18] arm: msm: add arch_has_speculative_dfetch()
Russell King - ARM Linux
linux at arm.linux.org.uk
Tue Jan 12 03:59:38 EST 2010
On Mon, Jan 11, 2010 at 04:28:53PM -0800, Daniel Walker wrote:
> 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 ?
Me, and they've been posted to this mailing list a few times in the last
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