Re: struct page to 36 (or 64) bit bus address?

[Alan Cox]

> I have a 64 bit PCI card which I'd like to do 64 bit DMA with. I have a
> struct page, but I don't see an easy way of determining what the bus
> address for that page is.
> 
> Is there a way to do it at all?

Yes but its not the right way to do it (bttv does it for example). You want 
to be using the pci or kiovec apis (Documentation/DMA-mapping.txt)

Thats important because it may well be an iommu that handles the mapping to
make the stuff visible - not the cpu