[ARM] dma: provide a better dma_map_page() implementation
We can translate a struct page directly to a DMA address using page_to_dma(). No need to use page_address() followed by virt_to_dma(). Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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@ -412,6 +412,19 @@ dma_map_single(struct device *dev, void *ptr, size_t size,
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return dma_addr;
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}
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dma_addr_t dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir)
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{
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dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n",
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__func__, page, offset, size, dir);
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BUG_ON(dir == DMA_NONE);
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return map_single(dev, page_address(page) + offset, size, dir);
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}
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EXPORT_SYMBOL(dma_map_page);
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/*
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* see if a mapped address was really a "safe" buffer and if so, copy
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* the data from the safe buffer back to the unsafe buffer and free up
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@ -227,13 +227,22 @@ extern dma_addr_t dma_map_single(struct device *,void *, size_t, enum dma_data_d
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* can regain ownership by calling dma_unmap_page() or
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* dma_sync_single_for_cpu().
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*/
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#ifndef CONFIG_DMABOUNCE
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static inline dma_addr_t
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dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir)
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{
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return dma_map_single(dev, page_address(page) + offset, size, dir);
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if (!arch_is_coherent())
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dma_cache_maint(page_address(page) + offset, size, dir);
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return page_to_dma(dev, page) + offset;
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}
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#else
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extern dma_addr_t dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir);
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#endif
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/**
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* dma_unmap_single - unmap a single buffer previously mapped
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