| Message ID | 1325388460-20678-1-git-send-email-richard.zhao@linaro.org |
|---|---|
| State | Changes Requested |
| Headers | show |
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? 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. Best regards Uwe
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/ |
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); }
dma_alloc_coherent memory may be bufferable. We need to add nececcary memory barrier. Signed-off-by: Richard Zhao <richard.zhao@linaro.org> --- drivers/dma/imx-sdma.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)