| Message ID | 1325428692-11473-3-git-send-email-richard.zhao@linaro.org |
|---|---|
| State | Changes Requested |
| Headers | show |
On Sun, Jan 01, 2012 at 10:38:12PM +0800, Richard Zhao wrote: > 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 | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c > index f8e87b5..9301bff 100644 > --- a/drivers/dma/imx-sdma.c > +++ b/drivers/dma/imx-sdma.c > @@ -394,6 +394,7 @@ static int sdma_config_ownership(struct sdma_channel *sdmac, > > static void sdma_enable_channel(struct sdma_engine *sdma, int channel) > { > + wmb(); > __raw_writel(1 << channel, sdma->regs + SDMA_H_START); Use writel(). That's what it's there for: #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE #define __iowmb() wmb() #endif #define writel_relaxed(v,c) ((void)__raw_writel((__force u32) \ cpu_to_le32(v),__mem_pci(c))) #define writel(v,c) ({ __iowmb(); writel_relaxed(v,c); })
On Tue, Jan 03, 2012 at 05:46:39PM +0000, Russell King - ARM Linux wrote: > On Sun, Jan 01, 2012 at 10:38:12PM +0800, Richard Zhao wrote: > > 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 | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c > > index f8e87b5..9301bff 100644 > > --- a/drivers/dma/imx-sdma.c > > +++ b/drivers/dma/imx-sdma.c > > @@ -394,6 +394,7 @@ static int sdma_config_ownership(struct sdma_channel *sdmac, > > > > static void sdma_enable_channel(struct sdma_engine *sdma, int channel) > > { > > + wmb(); > > __raw_writel(1 << channel, sdma->regs + SDMA_H_START); > > Use writel(). That's what it's there for: > > #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE > #define __iowmb() wmb() > #endif > #define writel_relaxed(v,c) ((void)__raw_writel((__force u32) \ > cpu_to_le32(v),__mem_pci(c))) > #define writel(v,c) ({ __iowmb(); writel_relaxed(v,c); }) Why does writel always call wmb? ioremap memory needs mb too? Isn't it supposed to be when there's prior touch of dma memory? Thanks Richard > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
Hi Sascha, On Wed, Jan 04, 2012 at 10:31:58AM +0800, Richard Zhao wrote: > On Tue, Jan 03, 2012 at 05:46:39PM +0000, Russell King - ARM Linux wrote: > > On Sun, Jan 01, 2012 at 10:38:12PM +0800, Richard Zhao wrote: > > > 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 | 1 + > > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c > > > index f8e87b5..9301bff 100644 > > > --- a/drivers/dma/imx-sdma.c > > > +++ b/drivers/dma/imx-sdma.c > > > @@ -394,6 +394,7 @@ static int sdma_config_ownership(struct sdma_channel *sdmac, > > > > > > static void sdma_enable_channel(struct sdma_engine *sdma, int channel) > > > { > > > + wmb(); > > > __raw_writel(1 << channel, sdma->regs + SDMA_H_START); > > > > Use writel(). That's what it's there for: > > > > #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE > > #define __iowmb() wmb() > > #endif > > #define writel_relaxed(v,c) ((void)__raw_writel((__force u32) \ > > cpu_to_le32(v),__mem_pci(c))) > > #define writel(v,c) ({ __iowmb(); writel_relaxed(v,c); }) > Why does writel always call wmb? ioremap memory needs mb too? > Isn't it supposed to be when there's prior touch of dma memory? What do you think? Thanks Richard > > Thanks > Richard > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index f8e87b5..9301bff 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -394,6 +394,7 @@ static int sdma_config_ownership(struct sdma_channel *sdmac, 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 | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)