On some platforms, a dma_addr_t is only 32 bits wide, but the bus addresses can be 64 bits wide. For peer-to-peer DMA, a device needs to use the full 64-bit address. Therefore, introduce a DMA address type that is not constrained by the CPU DMA address size. This is only needed for peer-to-peer DMA, so guard this definition with a CONFIG_HAS_DMA_P2P check. Signed-off-by: Will Davis <wdavis@xxxxxxxxxx> --- include/linux/types.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/include/linux/types.h b/include/linux/types.h index 8715287..dd85173 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -140,13 +140,13 @@ typedef unsigned long blkcnt_t; #define pgoff_t unsigned long /* - * A dma_addr_t can hold any valid DMA address, i.e., any address returned + * A dma_addr_t can hold any valid DMA address, i.e., most addresses returned * by the DMA API. * * If the DMA API only uses 32-bit addresses, dma_addr_t need only be 32 * bits wide. Bus addresses, e.g., PCI BARs, may be wider than 32 bits, * but drivers do memory-mapped I/O to ioremapped kernel virtual addresses, - * so they don't care about the size of the actual bus addresses. + * so they don't care about the size of the actual bus addresses in most cases. */ #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT typedef u64 dma_addr_t; @@ -154,6 +154,15 @@ typedef u64 dma_addr_t; typedef u32 dma_addr_t; #endif +/* + * Unlike dma_addr_t, a dma_peer_addr_t can hold any bus address for the + * platform. Drivers should only need this for peer-to-peer use cases, where + * the DMA target is also on the bus. + */ +#ifdef CONFIG_HAS_DMA_P2P +typedef u64 dma_peer_addr_t; +#endif + typedef unsigned __bitwise__ gfp_t; typedef unsigned __bitwise__ fmode_t; typedef unsigned __bitwise__ oom_flags_t; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
