Re: [net-next PATCH 04/27] arch/arc: Add option to skip sync on DMA mapping

[Vineet Gupta]

On 10/25/2016 02:38 PM, Alexander Duyck wrote:
> This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
> avoid invoking cache line invalidation if the driver will just handle it
> later via a sync_for_cpu or sync_for_device call.
>
> Cc: Vineet Gupta 
> Cc: linux-snps-...@lists.infradead.org
> Signed-off-by: Alexander Duyck 
> ---
>  arch/arc/mm/dma.c |5 -

Acked-by: Vineet Gupta 

>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
> index 20afc65..6303c34 100644
> --- a/arch/arc/mm/dma.c
> +++ b/arch/arc/mm/dma.c
> @@ -133,7 +133,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, 
> struct page *page,
>   unsigned long attrs)
>  {
>   phys_addr_t paddr = page_to_phys(page) + offset;
> - _dma_cache_sync(paddr, size, dir);
> +
> + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
> + _dma_cache_sync(paddr, size, dir);
> +
>   return plat_phys_to_dma(dev, paddr);
>  }
>  
>
>

[net-next PATCH 04/27] arch/arc: Add option to skip sync on DMA mapping

[Alexander Duyck]

This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Cc: Vineet Gupta 
Cc: linux-snps-...@lists.infradead.org
Signed-off-by: Alexander Duyck 
---
 arch/arc/mm/dma.c |5 -
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 20afc65..6303c34 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -133,7 +133,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, 
struct page *page,
unsigned long attrs)
 {
phys_addr_t paddr = page_to_phys(page) + offset;
-   _dma_cache_sync(paddr, size, dir);
+
+   if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+   _dma_cache_sync(paddr, size, dir);
+
return plat_phys_to_dma(dev, paddr);
 }