Hi all. I have question about mapping memory page in l4linux. I think “dma_map_page” function seem malfunction in below code. struct page *new_page; u32 linux_phys_addr; new_page = alloc_page(GFP_HIGHUSER | __GFP_ZERO | __GFP_NORETRY | __GFP_NOWARN | __GFP_COLD); linux_phys_addr = dma_map_page(NULL, new_page, 0, PAGE_SIZE, DMA_BIDIRECTIONAL); ////// PAGE_SIZE is 4KB _______________________________________________________________ new_page | linux_phys_addr | correct linux_phys_addr | ----------------|----------------------------|------------------------------ | 0xe54b20 0x325d9000 0x48b54b20 0xe54b40 0x325da000 0x48b54b40 0xe54b60 0x325db000 0x48b54b60 as H/W ram-base is 0x40000000, 0x30000000 base address can’t be mapped. Does anybody know a way to work dma_map_page? Best.