@@ -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;
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@nvidia.com> --- include/linux/types.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)