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arm64: Allow for different DMA and CPU bus offsets

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On arm64, all SoCs we supported so far either have an IOMMU or have bus
addresses equal to CPU addresses.

However, with the Raspberry Pi 3 coming up, this is no longer true. To
allow DMA to work with an AArch64 kernel on those devices, let's allow
devices to have DMA offsets again.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Alexander Graf 2016-06-03 08:18:22 +02:00 committed by Eric Anholt
parent 1a695a905c
commit 1a9a0536d8
1 changed files with 15 additions and 2 deletions
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17
arch/arm64/include/asm/dma-mapping.h
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@ -66,12 +66,16 @@ static inline bool is_device_dma_coherent(struct device *dev)
static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
return (dma_addr_t)paddr;
dma_addr_t dev_addr = (dma_addr_t)paddr;
return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
}
static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
{
return (phys_addr_t)dev_addr;
phys_addr_t paddr = (phys_addr_t)dev_addr;
return paddr + ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
}
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
@ -86,5 +90,14 @@ static inline void dma_mark_clean(void *addr, size_t size)
{
}
/* Override for dma_max_pfn() */
static inline unsigned long dma_max_pfn(struct device *dev)
{
dma_addr_t dma_max = (dma_addr_t)*dev->dma_mask;
return (ulong)dma_to_phys(dev, dma_max) >> PAGE_SHIFT;
}
#define dma_max_pfn(dev) dma_max_pfn(dev)
#endif /* __KERNEL__ */
#endif /* __ASM_DMA_MAPPING_H */