arm64: default to the direct mapping in get_arch_dma_ops

Otherwise the direct mapping won't work at all given that a NULL
dev->dma_ops causes a fallback.  Note that we already explicitly set
dev->dma_ops to dma_dummy_ops for dma-incapable devices, so this
fallback should not be needed anyway.

Fixes: 356da6d0cd ("dma-mapping: bypass indirect calls for dma-direct")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
index 273e778..95dbf3e 100644 (file)
--- a/arch/arm64/include/asm/dma-mapping.h
+++ b/arch/arm64/include/asm/dma-mapping.h
@@ -26,11 +26,7 @@
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 {
-       /*
-        * We expect no ISA devices, and all other DMA masters are expected to
-        * have someone call arch_setup_dma_ops at device creation time.
-        */
-       return &dma_dummy_ops;
+       return NULL;
 }
 
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,