On Tue, Sep 23, 2014 at 2:56 AM, Arnd Bergmann [off-list ref] wrote:

On Monday 22 September 2014 12:43:17 Liviu Dudau wrote:

quoted

quoted

From e798af4fc2f664d1aff7e863489b8298f90e716e Mon Sep 17 00:00:00 2001
From: Robert Richter <redacted>
Date: Mon, 22 Sep 2014 10:46:01 +0200
Subject: [PATCH] OF: PCI: Fix creation of mem-mapped pci host bridges

The pci host bridge was not created if io_base was not set when
calling of_pci_get_host_bridge_resources(). This is esp. the case for
mem-mapped io (IORESOURCE_MEM). This patch fixes this. Function
parameter io_base is optional now.

I think the message is misleading. What you want to do is make io_base
optional for the case where the PCI host bridge only expects to have only
IORESOURCE_MEM ranges and doesn't care about IORESOURCE_IO ones.

As I'm going to touch this area again to address a comment from Bjorn,
do you mind if I roll this patch into mine with your Signed-off-by and
the mention that you have made io_base optional?

I think the best way to deal with this is to move the check for
io_base down into the place where it is used: As long as the DT only
specifies IORESOURCE_MEM windows, we don't need to look at io_base,
but if the host controller driver does not support IORESOURCE_IO
while the DT specifies it, I guess it would be nice to return an
error.

The DT may specify it, but the h/w could be broken in some way so the
host driver chooses to ignore it. I don't think we should force the
host driver to provide a pointer in that case. Also, would we want it
added to the resource list if it is not going to be used?

Rob