On Wed, 2011-05-18 at 21:02 +0800, Leon Woestenberg wrote: > Hello all, > > memory allocated with pci_alloc_consistent() returns the (kernel) > virtual address and the bus address (which may be different from the > physical memory address). > > What is the correct implementation of the driver mmap (file operation > method) for such memory? > > I assume remap_pfn_range() must be used, but how can I find out the > correct arguments, such as the physical address? > > Some plainly use the bus address as the physical address to > remap_pfn_range, but that seems plain wrong to be in general. > > This questions seems a FAQ, but I found different (and > contradictionary) answers on Google. why use pci_alloc_consistent? you can allocate pages and mmap it to userspace. when you want to do dma, you can use pci_map_page to get dma address for the pages and do whatever. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
