[PATCH 3/4] x86: allow dma_get_required_mask() to be overridden

From: David Vrabel
Date: Fri Dec 05 2014 - 09:08:25 EST


Use dma_ops->get_required_mask() if provided, defaulting to
dma_get_requried_mask_from_max_pfn().

This is needed on systems (such as Xen PV guests) where the DMA
address and the physical address are not equal.

ARCH_HAS_DMA_GET_REQUIRED_MASK is defined in asm/device.h instead of
asm/dma-mapping.h because linux/dma-mapping.h uses the define before
including asm/dma-mapping.h

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
arch/x86/include/asm/device.h | 2 ++
arch/x86/kernel/pci-dma.c | 8 ++++++++
2 files changed, 10 insertions(+)

diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
index 03dd729..10bc628 100644
--- a/arch/x86/include/asm/device.h
+++ b/arch/x86/include/asm/device.h
@@ -13,4 +13,6 @@ struct dev_archdata {
struct pdev_archdata {
};

+#define ARCH_HAS_DMA_GET_REQUIRED_MASK
+
#endif /* _ASM_X86_DEVICE_H */
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index a25e202..5154400 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -140,6 +140,14 @@ void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
free_pages((unsigned long)vaddr, get_order(size));
}

+u64 dma_get_required_mask(struct device *dev)
+{
+ if (dma_ops->get_required_mask)
+ return dma_ops->get_required_mask(dev);
+ return dma_get_required_mask_from_max_pfn(dev);
+}
+EXPORT_SYMBOL_GPL(dma_get_required_mask);
+
/*
* See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
* parameter documentation.
--
1.7.10.4

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