diff options
Diffstat (limited to 'include/linux/dma-mapping.h')
| -rw-r--r-- | include/linux/dma-mapping.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 4d450672b7d6..da90f20e11c1 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -71,6 +71,14 @@ #define DMA_ATTR_PRIVILEGED (1UL << 9) /* + * This is a hint to the DMA-mapping subsystem that the device is expected + * to overwrite the entire mapped size, thus the caller does not require any + * of the previous buffer contents to be preserved. This allows + * bounce-buffering implementations to optimise DMA_FROM_DEVICE transfers. + */ +#define DMA_ATTR_OVERWRITE (1UL << 10) + +/* * 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 |