x86: Introduce CONFIG_X86_DMA_REMAP (f7219a53) · Commits · 戴 / test

The default functions phys_to_dma, dma_to_phys implement identity mapping as fast inline functions. Some systems, however, may need a custom function to implement its own mapping between CPU addresses and device addresses. This new configuration option allows the functions to be external when needed (such as for the ConneXt device) Signed-off-by:

Alessandro Rubini <rubini@gnudd.com> Link: http://lkml.kernel.org/r/6e4329b772df675f1c442f68e59e844e4dd8c965.1333560789.git.rubini@gnudd.com Acked-by:

Giancarlo Asnaghi <giancarlo.asnaghi@st.com> Cc: Alan Cox <alan@linux.intel.com> Signed-off-by:

H. Peter Anvin <hpa@zytor.com>

arch/x86/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -2220,6 +2220,9 @@ config X86_DEV_DMA_OPS
		bool
		depends on X86_64

		config X86_DMA_REMAP
		bool

		source "net/Kconfig"

		source "drivers/Kconfig"

arch/x86/include/asm/dma-mapping.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -62,6 +62,12 @@ extern void dma_generic_alloc_coherent(struct device dev, size_t size,
		dma_addr_t *dma_addr, gfp_t flag,
		struct dma_attrs *attrs);

		#ifdef CONFIG_X86_DMA_REMAP /* Platform code defines bridge-specific code */
		extern bool dma_capable(struct device *dev, dma_addr_t addr, size_t size);
		extern dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
		extern phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
		#else

		static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
		{
		if (!dev->dma_mask)
		@@ -79,6 +85,7 @@ static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
		{
		return daddr;
		}
		#endif /* CONFIG_X86_DMA_REMAP */

		static inline void
		dma_cache_sync(struct device dev, void vaddr, size_t size,

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