[PATCH 6/8] arm: mach-armada: add support for Armada XP board with device tree

On 15/05/12 16:32, Arnd Bergmann wrote:

On Tuesday 15 May 2012, Ben Dooks wrote:

quoted

quoted

Agreed. When looking at the code, I wasn't sure why PCI mappings were
needed so early. Surely, the minimal mappings to get an UART are quite
useful to have very early, but why PCI?

I think it was because that PCI was initialised early and requires a
large mapping space. It is very likely to be legacy kernel stuff that
people have kept copying through.

No, as Rob pointed out, we might not need them early, but we definitely
want a fixed address for the PIO window, which ioremap does not
provide.

Yes, I can see a not a lot of fun with multiple PCIe busses and the
need for a single IO space. You'll probably have to reserve a VM
area for people to use for legacy-IO accesses.

With PCIe, there should be less old-style IO as PCIe devices are
encouraged to go 32bit MMIO.

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius