diff options
| -rw-r--r-- | include/linux/dma-mapping.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 51e93d44b826..943479fb77f6 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -67,12 +67,6 @@ */ #define DMA_ATTR_PRIVILEGED (1UL << 9) -/* - * A dma_addr_t can hold any valid DMA or bus address for the platform. - * It can be given to a device to use as a DMA source or target. A CPU cannot - * reference a dma_addr_t directly because there may be translation between - * its physical address space and the bus address space. - */ struct dma_map_ops { void* (*alloc)(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, @@ -131,6 +125,16 @@ struct dma_map_ops { unsigned long (*get_merge_boundary)(struct device *dev); }; +/* + * A dma_addr_t can hold any valid DMA or bus address for the platform. It can + * be given to a device to use as a DMA source or target. It is specific to a + * given device and there may be a translation between the CPU physical address + * space and the bus address space. + * + * DMA_MAPPING_ERROR is the magic error code if a mapping failed. It should not + * be used directly in drivers, but checked for using dma_mapping_error() + * instead. + */ #define DMA_MAPPING_ERROR (~(dma_addr_t)0) extern const struct dma_map_ops dma_virt_ops; |