diff options
| -rw-r--r-- | include/linux/dma-mapping.h | 5 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 23 |
2 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index de41a4f0b9f6..10dc9ac3cccb 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -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; diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index c8b4e46407ba..18ba1ac93fc1 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -223,6 +223,29 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, } /** + * 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 * @vma: vm_area_struct describing requested user mapping |