| Message ID | 1484040220-11517-1-git-send-email-jun.nie@linaro.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Tue, Jan 10, 2017 at 05:23:40PM +0800, Jun Nie wrote: > Fix build warning that related to PAGE_SIZE. The maximum DMA > length has nothing to do with PAGE_SIZE, just use a fix number > for the definition. > > drivers/dma/zx_dma.c: In function 'zx_dma_prep_memcpy': > drivers/dma/zx_dma.c:523:8: warning: division by zero [-Wdiv-by-zero] > drivers/dma/zx_dma.c: In function 'zx_dma_prep_slave_sg': > drivers/dma/zx_dma.c:567:11: warning: division by zero [-Wdiv-by-zero] > > Signed-off-by: Jun Nie <jun.nie@linaro.org> HDMI audio works fine with the change, so: Tested-by: Shawn Guo <shawn.guo@linaro.org> But out of curiosity ... > --- > drivers/dma/zx_dma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma/zx_dma.c b/drivers/dma/zx_dma.c > index 42ff3e6..2bb6953 100644 > --- a/drivers/dma/zx_dma.c > +++ b/drivers/dma/zx_dma.c > @@ -26,7 +26,7 @@ > > #define DRIVER_NAME "zx-dma" > #define DMA_ALIGN 4 > -#define DMA_MAX_SIZE (0x10000 - PAGE_SIZE) > +#define DMA_MAX_SIZE (0x10000 - 512) Why do we need to minus some amount of bytes from 64KiB size for DMA_MAX_SIZE at all? > #define LLI_BLOCK_SIZE (4 * PAGE_SIZE) Why do we need to have LLI_BLOCK_SIZE vary with PAGE_SIZE? Shawn > > #define REG_ZX_SRC_ADDR 0x00 > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2017年01月11日 08:57, Shawn Guo wrote: > On Tue, Jan 10, 2017 at 05:23:40PM +0800, Jun Nie wrote: >> Fix build warning that related to PAGE_SIZE. The maximum DMA >> length has nothing to do with PAGE_SIZE, just use a fix number >> for the definition. >> >> drivers/dma/zx_dma.c: In function 'zx_dma_prep_memcpy': >> drivers/dma/zx_dma.c:523:8: warning: division by zero [-Wdiv-by-zero] >> drivers/dma/zx_dma.c: In function 'zx_dma_prep_slave_sg': >> drivers/dma/zx_dma.c:567:11: warning: division by zero [-Wdiv-by-zero] >> >> Signed-off-by: Jun Nie <jun.nie@linaro.org> > > HDMI audio works fine with the change, so: > > Tested-by: Shawn Guo <shawn.guo@linaro.org> > > But out of curiosity ... > >> --- >> drivers/dma/zx_dma.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/dma/zx_dma.c b/drivers/dma/zx_dma.c >> index 42ff3e6..2bb6953 100644 >> --- a/drivers/dma/zx_dma.c >> +++ b/drivers/dma/zx_dma.c >> @@ -26,7 +26,7 @@ >> >> #define DRIVER_NAME "zx-dma" >> #define DMA_ALIGN 4 >> -#define DMA_MAX_SIZE (0x10000 - PAGE_SIZE) >> +#define DMA_MAX_SIZE (0x10000 - 512) > > Why do we need to minus some amount of bytes from 64KiB size for > DMA_MAX_SIZE at all? For better alignment of DMA transfer size. Maximum size 0xFFFF minus 32 or 64 shall be OK, but I prefer to 512 for better performance and safe. > >> #define LLI_BLOCK_SIZE (4 * PAGE_SIZE) > > Why do we need to have LLI_BLOCK_SIZE vary with PAGE_SIZE? It is a trade off for dmam_pool size. 4 pages size does introduce pressure to memory management and allocation, and size is enough for most of DMA descriptor usage. > > Shawn > >> >> #define REG_ZX_SRC_ADDR 0x00 >> -- >> 1.9.1 >> -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jan 10, 2017 at 05:23:40PM +0800, Jun Nie wrote: > Fix build warning that related to PAGE_SIZE. The maximum DMA > length has nothing to do with PAGE_SIZE, just use a fix number > for the definition. > > drivers/dma/zx_dma.c: In function 'zx_dma_prep_memcpy': > drivers/dma/zx_dma.c:523:8: warning: division by zero [-Wdiv-by-zero] > drivers/dma/zx_dma.c: In function 'zx_dma_prep_slave_sg': > drivers/dma/zx_dma.c:567:11: warning: division by zero [-Wdiv-by-zero] Applied, thanks
diff --git a/drivers/dma/zx_dma.c b/drivers/dma/zx_dma.c index 42ff3e6..2bb6953 100644 --- a/drivers/dma/zx_dma.c +++ b/drivers/dma/zx_dma.c @@ -26,7 +26,7 @@ #define DRIVER_NAME "zx-dma" #define DMA_ALIGN 4 -#define DMA_MAX_SIZE (0x10000 - PAGE_SIZE) +#define DMA_MAX_SIZE (0x10000 - 512) #define LLI_BLOCK_SIZE (4 * PAGE_SIZE) #define REG_ZX_SRC_ADDR 0x00
Fix build warning that related to PAGE_SIZE. The maximum DMA length has nothing to do with PAGE_SIZE, just use a fix number for the definition. drivers/dma/zx_dma.c: In function 'zx_dma_prep_memcpy': drivers/dma/zx_dma.c:523:8: warning: division by zero [-Wdiv-by-zero] drivers/dma/zx_dma.c: In function 'zx_dma_prep_slave_sg': drivers/dma/zx_dma.c:567:11: warning: division by zero [-Wdiv-by-zero] Signed-off-by: Jun Nie <jun.nie@linaro.org> --- drivers/dma/zx_dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)