* [PATCH] dma/imx-sdma: add wmb before enable/run a channel
@ 2012-01-01 3:27 Richard Zhao
2012-01-01 7:14 ` Uwe Kleine-König
0 siblings, 1 reply; 3+ messages in thread
From: Richard Zhao @ 2012-01-01 3:27 UTC (permalink / raw)
To: linux-kernel, linux-arm-kernel
Cc: kernel, shawn.guo, vinod.koul, dan.j.williams, eric.miao, patches,
Richard Zhao
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(-)
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);
}
--
1.7.4.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] dma/imx-sdma: add wmb before enable/run a channel
2012-01-01 3:27 [PATCH] dma/imx-sdma: add wmb before enable/run a channel Richard Zhao
@ 2012-01-01 7:14 ` Uwe Kleine-König
2012-01-01 13:29 ` Richard Zhao
0 siblings, 1 reply; 3+ messages in thread
From: Uwe Kleine-König @ 2012-01-01 7:14 UTC (permalink / raw)
To: Richard Zhao
Cc: linux-kernel, linux-arm-kernel, kernel, shawn.guo, vinod.koul,
dan.j.williams, eric.miao, patches
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
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dma/imx-sdma: add wmb before enable/run a channel
2012-01-01 7:14 ` Uwe Kleine-König
@ 2012-01-01 13:29 ` Richard Zhao
0 siblings, 0 replies; 3+ messages in thread
From: Richard Zhao @ 2012-01-01 13:29 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: linux-kernel, linux-arm-kernel, kernel, shawn.guo, vinod.koul,
dan.j.williams, eric.miao, patches
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/ |
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-01-01 3:27 [PATCH] dma/imx-sdma: add wmb before enable/run a channel Richard Zhao
2012-01-01 7:14 ` Uwe Kleine-König
2012-01-01 13:29 ` Richard Zhao
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