MAX_DMA_PFN        93 arch/mips/include/asm/dma.h #define MAX_DMA_PFN		PFN_DOWN(virt_to_phys((void *)MAX_DMA_ADDRESS))
MAX_DMA_PFN        74 arch/x86/include/asm/dma.h #define MAX_DMA_PFN   ((16UL * 1024 * 1024) >> PAGE_SHIFT)