Messages in this thread | | | Date | Sun, 1 Jan 2012 21:29:38 +0800 | From | Richard Zhao <> | Subject | Re: [PATCH] dma/imx-sdma: add wmb before enable/run a channel |
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On Sun, Jan 01, 2012 at 08:14:25AM +0100, Uwe Kleine-König wrote: > Hello Richard, > > On Sun, Jan 01, 2012 at 11:27:40AM +0800, Richard Zhao wrote: > > dma_alloc_coherent memory may be bufferable. We need to add > > nececcary memory barrier. > necessary > > > > > Signed-off-by: Richard Zhao <richard.zhao@linaro.org> > > --- > > drivers/dma/imx-sdma.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c > > index 2ebb2bc..8cd9492 100644 > > --- a/drivers/dma/imx-sdma.c > > +++ b/drivers/dma/imx-sdma.c > > @@ -403,6 +403,7 @@ static int sdma_run_channel(struct sdma_channel *sdmac) > > > > init_completion(&sdmac->done); > > > > + wmb(); > > __raw_writel(1 << channel, sdma->regs + SDMA_H_START); > > > > ret = wait_for_completion_timeout(&sdmac->done, HZ); > > @@ -809,6 +810,7 @@ out: > > > > static void sdma_enable_channel(struct sdma_engine *sdma, int channel) > > { > > + wmb(); > > __raw_writel(1 << channel, sdma->regs + SDMA_H_START); > > } > I don't know the sdma code very well, but wouldn't it be nice to call > sdma_enable_channel() in sdma_run_channel() instead of open coding it? right. > > As you probably need some rearrangements to have sdma_enable_channel() > declared in sdma_run_channel() this might be better done with a seperate > patch. It'll save one wmb.
Thanks Richard > > Best regards > Uwe > > -- > Pengutronix e.K. | Uwe Kleine-König | > Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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