参照元†
- DMA アドレス
- アーキテクチャにより 64bit の場合と 32bit の場合がある。
/*
* A dma_addr_t can hold any valid DMA address, i.e., any address 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.
*/
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
typedef u64 dma_addr_t;
#else
typedef u32 dma_addr_t;
#endif
コメント†