[RFC] ARM DMA mapping TODO, v1

[Benjamin Herrenschmidt]

> As I said above, I don't think bus code can do it.  Take my example
> above of a tulip pci device on x86 and a tulip pci device on ARM.  Both
> use the same PCI code.
> 
> Maybe something in asm/pci.h - but that invites having lots of bus
> specific header files in asm/.
> 
> A better solution imho would be to have an architecture callback for
> struct device which gets registered, which can inspect the type of
> the device, and set the flag depending on where it appears in the
> tree.

Now -that's gross :-)

For PCI you can have the flag propagate from the PHB down, for busses
without a bus type (platform) then whoever instanciate them (the
platform code) can set that appropriately.

Ben.