Re: PCI DMA to small buffers on cache-incoherent arch

[Benjamin Herrenschmidt]

>   Those would be designed so they could be shared between
>   devices, invisibly to code talking to a struct device.
>
>   Example:  all USB devices connected to a given bus would
>   normally delegate to the PCI device underlying that bus.
>   (Except for non-PCI host controllers, of course!)
>
>   And the PCI versions of those methods have rather obvious
>   implementations ... :)

Yup. The simplest way I see here is to have a device automatically
inherit, by default, his parent device ones. The arch will provide
default "root" allocators, so a fully coherent or fully non-coherent
arch may not have to do anything but these.

Now, if a given bus in the arch need specific quirks, it's up to
the bus device node to put it's own versions to be used by it's
childs.

Ben.