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

On 15/05/12 15:58, Thomas Petazzoni wrote:

Le Tue, 15 May 2012 15:32:36 +0100,
Ben Dooks[off-list ref]  a ?crit :

quoted

Yes, the number of times I've viewed the kernel and seen very similar
code replicated multiple times tends to make me burst into tears.

quoted

   * Maybe those mappings can be done using a normal ioremap() rather
     than in ->map_io(), according to DT informations (but most
other ARM SoC support at the moment seem to do PCI mappings using
static mappings in ->map_io)

That's a very old way of doing it. I'm pretty sure there's no reason
to get these allocated so early.

I believe you can probably leave the PCI/PCIe bindings until you have
enough kernel state to do ioremap() or similar and then associate the
necessary mappings with the bus creation.

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.

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