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Commit e29ccc18 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-mapping: add a dma_can_mmap helper



Add a helper to check if DMA allocations for a specific device can be
mapped to userspace using dma_mmap_*.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent f9f3232a
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+5 −0
Original line number Diff line number Diff line
@@ -463,6 +463,7 @@ int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		unsigned long attrs);
bool dma_can_mmap(struct device *dev);
int dma_supported(struct device *dev, u64 mask);
int dma_set_mask(struct device *dev, u64 mask);
int dma_set_coherent_mask(struct device *dev, u64 mask);
@@ -554,6 +555,10 @@ static inline int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
{
	return -ENXIO;
}
static inline bool dma_can_mmap(struct device *dev)
{
	return false;
}
static inline int dma_supported(struct device *dev, u64 mask)
{
	return 0;
+23 −0
Original line number Diff line number Diff line
@@ -222,6 +222,29 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
#endif /* !CONFIG_ARCH_NO_COHERENT_DMA_MMAP */
}

/**
 * dma_can_mmap - check if a given device supports dma_mmap_*
 * @dev: device to check
 *
 * Returns %true if @dev supports dma_mmap_coherent() and dma_mmap_attrs() to
 * map DMA allocations to userspace.
 */
bool dma_can_mmap(struct device *dev)
{
	const struct dma_map_ops *ops = get_dma_ops(dev);

	if (IS_ENABLED(CONFIG_ARCH_NO_COHERENT_DMA_MMAP))
		return false;

	if (dma_is_direct(ops)) {
		return dev_is_dma_coherent(dev) ||
			IS_ENABLED(CONFIG_ARCH_HAS_DMA_COHERENT_TO_PFN);
	}

	return ops->mmap != NULL;
}
EXPORT_SYMBOL_GPL(dma_can_mmap);

/**
 * dma_mmap_attrs - map a coherent DMA allocation into user space
 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices