[PATCH v9 01/18] arm: make SWIOTLB available

[Stefano Stabellini]

Russell,
this is the only patch that needs an ack at the moment.
As you commented on it before and I have already addressed your comments
few versions ago, unless you have any complaints I am going to add it to
linux-next and I am thinking of merging it during the next merge window.

On Fri, 25 Oct 2013, Stefano Stabellini wrote:
> IOMMU_HELPER is needed because SWIOTLB calls iommu_is_span_boundary,
> provided by lib/iommu_helper.c.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> CC: will.deacon at arm.com
> CC: linux at arm.linux.org.uk
> 
> 
> Changes in v8:
> - use __phys_to_pfn and __pfn_to_phys.
> 
> Changes in v7:
> - dma_mark_clean: empty implementation;
> - in dma_capable use coherent_dma_mask if dma_mask hasn't been
>   allocated.
> 
> Changes in v6:
> - check for dev->dma_mask being NULL in dma_capable.
> 
> Changes in v5:
> - implement dma_mark_clean using dmac_flush_range.
> 
> Changes in v3:
> - dma_capable: do not treat dma_mask as a limit;
> - remove SWIOTLB dependency on NEED_SG_DMA_LENGTH.
> ---
>  arch/arm/Kconfig                   |    6 +++++
>  arch/arm/include/asm/dma-mapping.h |   37 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 43 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..01b5a3d 100644
> --- a/arch/arm/include/asm/dma-mapping.h
> +++ b/arch/arm/include/asm/dma-mapping.h
> @@ -10,6 +10,7 @@
>  
>  #include <asm-generic/dma-coherent.h>
>  #include <asm/memory.h>
> +#include <asm/cacheflush.h>
>  
>  #define DMA_ERROR_CODE	(~0)
>  extern struct dma_map_ops arm_dma_ops;
> @@ -86,6 +87,42 @@ 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)
> +		mask = *dev->dma_mask;
> +	else 
> +		mask = dev->coherent_dma_mask;
> +
> +	if (mask == 0)
> +		return 0;
> +
> +	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
>