Re: [Xen-devel] [PATCH v9 01/18] arm: make SWIOTLB available

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 30 Oct 2013, Stefano Stabellini wrote:
> On Tue, 29 Oct 2013, Russell King - ARM Linux wrote:
> > So... what I'm saying is please fix xgmac to use the DMA API properly
> > rather than working around such problems. :)
>  
> OK.
> Would the appended patch fix your concerns?

ping?

> ---
> 
> arm: make SWIOTLB available
> 
> IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
> provided by lib/iommu_helper.c.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> 
> Changes in v9:
> - remove uneeded include asm/cacheflush.h;
> - just return 0 if !dev->dma_mask in dma_capable.
> 
> ---
>  arch/arm/Kconfig                   |    6 ++++++
>  arch/arm/include/asm/dma-mapping.h |   33 +++++++++++++++++++++++++++++++++
>  2 files changed, 39 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 1ad6fb6..b08374f 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1872,6 +1872,12 @@ config CC_STACKPROTECTOR
>         neutralized via a kernel panic.
>         This feature requires gcc version 4.2 or above.
>  
> +config SWIOTLB
> +     def_bool y
> +
> +config IOMMU_HELPER
> +     def_bool SWIOTLB
> +
>  config XEN_DOM0
>       def_bool y
>       depends on XEN
> diff --git a/arch/arm/include/asm/dma-mapping.h 
> b/arch/arm/include/asm/dma-mapping.h
> index 5b579b9..1ad2c17 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -86,6 +86,39 @@ static inline dma_addr_t virt_to_dma(struct device *dev, 
> void *addr)
>  }
>  #endif
>  
> +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> +     unsigned int offset = paddr & ~PAGE_MASK;
> +     return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
> +}
> +
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t 
> dev_addr)
> +{
> +     unsigned int offset = dev_addr & ~PAGE_MASK;
> +     return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
> +}
> +
> +static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t 
> size)
> +{
> +     u64 limit, mask;
> +
> +     if (!dev->dma_mask)
> +             return 0;
> +
> +     mask = *dev->dma_mask;
> +
> +     limit = (mask + 1) & ~mask;
> +     if (limit && size > limit)
> +             return 0;
> +
> +     if ((addr | (addr + size - 1)) & ~mask)
> +             return 0;
> +
> +     return 1;
> +}
> +
> +static inline void dma_mark_clean(void *addr, size_t size) { }
> +
>  /*
>   * DMA errors are defined by all-bits-set in the DMA address.
>   */
> -- 
> 1.7.2.5
> 

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