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

From: Stefano Stabellini
Date: Fri Oct 25 2013 - 07:09:37 EST


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@xxxxxxxxxxxxx>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> CC: will.deacon@xxxxxxx
> CC: linux@xxxxxxxxxxxxxxxx
>
>
> 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
>
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