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authorChristoph Hellwig <hch@lst.de>2018-04-16 15:24:51 +0200
committerChristoph Hellwig <hch@lst.de>2018-05-19 08:46:12 +0200
commit782e6769c0df744e773dc2acff71c974b3bba4e9 (patch)
tree4b7f513da50a3bce1cca7a28949258642e9c8ab7 /include/asm-generic
parent35ddb69cd223eea5b1c68af753ed014208b6144e (diff)
downloadlinux-782e6769c0df744e773dc2acff71c974b3bba4e9.tar.gz
dma-mapping: provide a generic dma-noncoherent implementation
Add a new dma_map_ops implementation that uses dma-direct for the
address mapping of streaming mappings, and which requires arch-specific
implemenations of coherent allocate/free.

Architectures have to provide flushing helpers to ownership trasnfers
to the device and/or CPU, and can provide optional implementations of
the coherent mmap functionality, and the cache_flush routines for
non-coherent long term allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/dma-mapping.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/asm-generic/dma-mapping.h b/include/asm-generic/dma-mapping.h
index 880a292d792f..ad2868263867 100644
--- a/include/asm-generic/dma-mapping.h
+++ b/include/asm-generic/dma-mapping.h
@@ -4,7 +4,16 @@
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 {
+	/*
+	 * Use the non-coherent ops if available.  If an architecture wants a
+	 * more fine-grained selection of operations it will have to implement
+	 * get_arch_dma_ops itself or use the per-device dma_ops.
+	 */
+#ifdef CONFIG_DMA_NONCOHERENT_OPS
+	return &dma_noncoherent_ops;
+#else
 	return &dma_direct_ops;
+#endif
 }
 
 #endif /* _ASM_GENERIC_DMA_MAPPING_H */