Re: [PATCH] MIPS: DMA: fix coherent alloc in non-coherent systems

[Markos Chandras]

Hi,

On 10/30/2014 01:48 AM, Leonid Yegoshin wrote:
> A default dma_alloc_coherent() fails to alloc a coherent memory on non-coherent
> systems in case of device->coherent_dma_mask covering the whole memory space.
> 
> In case of non-coherent systems the coherent memory on MIPS is restricted by
> size of un-cachable segment and should be located in ZONE_DMA.
> 
> Added __GFP_DMA flag in case of non-coherent systems to enforce an allocation
> of coherent memory in ZONE_DMA.
> 
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
> ---
>  .../include/asm/mach-cavium-octeon/dma-coherence.h |    2 +-
>  arch/mips/include/asm/mach-generic/dma-coherence.h |    2 +-
>  arch/mips/include/asm/mach-ip27/dma-coherence.h    |    2 +-
>  arch/mips/include/asm/mach-ip32/dma-coherence.h    |    2 +-
>  arch/mips/include/asm/mach-jazz/dma-coherence.h    |    2 +-
>  .../mips/include/asm/mach-loongson/dma-coherence.h |    2 +-
>  arch/mips/mm/dma-default.c                         |   11 ++++++++---
>  7 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> index f9f4486..fe0b465 100644
> --- a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> @@ -52,7 +52,7 @@ static inline int plat_dma_supported(struct device *dev, u64 mask)
>  	return 0;
>  }
>  
> -static inline int plat_device_is_coherent(struct device *dev)
> +static inline int plat_device_is_coherent(const struct device *dev)

Why adding const here?

>  {
>  	return 1;
>  }
> diff --git a/arch/mips/include/asm/mach-generic/dma-coherence.h b/arch/mips/include/asm/mach-generic/dma-coherence.h
> index b4563df..2283996 100644
> --- a/arch/mips/include/asm/mach-generic/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-generic/dma-coherence.h
> @@ -47,7 +47,7 @@ static inline int plat_dma_supported(struct device *dev, u64 mask)
>  	return 1;
>  }
>  
> -static inline int plat_device_is_coherent(struct device *dev)
> +static inline int plat_device_is_coherent(const struct device *dev)

likewise

>  {
>  #ifdef CONFIG_DMA_COHERENT
>  	return 1;
> diff --git a/arch/mips/include/asm/mach-ip27/dma-coherence.h b/arch/mips/include/asm/mach-ip27/dma-coherence.h
> index 4ffddfd..c7767e3 100644
> --- a/arch/mips/include/asm/mach-ip27/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-ip27/dma-coherence.h
> @@ -58,7 +58,7 @@ static inline int plat_dma_supported(struct device *dev, u64 mask)
>  	return 1;
>  }
>  
> -static inline int plat_device_is_coherent(struct device *dev)
> +static inline int plat_device_is_coherent(const struct device *dev)

likewise

>  {
>  	return 1;		/* IP27 non-cohernet mode is unsupported */
>  }
> diff --git a/arch/mips/include/asm/mach-ip32/dma-coherence.h b/arch/mips/include/asm/mach-ip32/dma-coherence.h
> index 104cfbc..a6b6a55 100644
> --- a/arch/mips/include/asm/mach-ip32/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-ip32/dma-coherence.h
> @@ -80,7 +80,7 @@ static inline int plat_dma_supported(struct device *dev, u64 mask)
>  	return 1;
>  }
>  
> -static inline int plat_device_is_coherent(struct device *dev)
> +static inline int plat_device_is_coherent(const struct device *dev)

likewise etc

Is it just a matter of consistence with the rest of the interfaces? Do
you need to move these into a separate patch since they don't quite fit
here.

-- 
markos
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