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.