Hello, On Wed, May 18, 2011 at 4:41 PM, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote: > On Wed, May 18, 2011 at 03:02:30PM +0200, Leon Woestenberg wrote: >> >> 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? > > You are going to use the physical address from the CPU side. So not > the bus address. Instead use the virtual address and find the > physical address from that. page_to_pfn() does a good job. > pci_alloc_consistent() returns a kernel virtual address. To find the page I think virt_to_page() suits me better, right? #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) > Then you can call 'vm_insert_page(vma...)' > > Or 'vm_insert_mixed' Thanks, that opens a whole new learning curve experience. Can I call vmalloc_to_page() on memory allocated with pci_alloc_consistent()? If so, then remap_vmalloc_range() looks promising. I could not find PCI driver examples calling vm_insert_page() and I am know I can trip into the different memory type pointers easily. How does your suggestion relate to using the vma ops fault() (formerly known as nopage() to mmap memory allocated by pci_alloc_consistent()? i.e. Such as suggested in http://www.gossamer-threads.com/lists/linux/kernel/702127#702127 > Use 'cscope' on the Linux kernel. Thanks for the suggestion. How would cscope help me find vm_insert_page() given my question? On hind-sight all questions seem to be easy once finding the correct Documentation / source-code in the first place. I usually use http://lxr.linux.no/ and friends. Regards, -- Leon -- 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
