[Xen-devel] [PATCH v4 03/10] arm: make SWIOTLB available

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

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 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 |   30 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ba412e0..c0bfb33 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1832,6 +1832,12 @@ 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..5b8eef9 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -86,6 +86,36 @@ 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, paddr >> PAGE_SHIFT) + 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 (dma_to_pfn(dev, dev_addr) << PAGE_SHIFT) + offset;
+}
+
+static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t 
size)
+{
+       u64 limit, 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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