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

Benjamin Herrenschmidt
2002-06-12T15:00:55Z

> 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.