Re: [PATCH v1 3/3] ARM64 LPC: update binding doc

[Rongrong Zou]

On 2016/1/13 18:09, liviu.dudau@xxxxxxx wrote:
> On Tue, Jan 12, 2016 at 11:54:59PM +0100, Arnd Bergmann wrote:
> > On Tuesday 12 January 2016 10:14:18 liviu.dudau@xxxxxxx wrote:
> > > OK, looking at of_translate_one() comments it looks like a missing "ranges" property is
> > > only accepted on PowerPC. I suggest you have an empty "ranges" property in your isa
> > > parent node, that will signal to the OF parsing code that the mapping is 1:1. Then have
> > > the IPMI node use the reg = <0x0 0xe4 4>; property values instead of reg = <0x1 0xe4 4>;
> >
> > A missing ranges property means that there is no translation, while an
> > empty ranges means a 1:1 translation to the parent bus.
> >
> > We really want the former here, as I/O port addresses are not mapped into
> > the MMIO space of the parent bus.
>
> Agree. However of_translate_one()'s behaviour doesn't match our expectations and I have no
> useful suggestions on what the right behaviour should be.

I had tried to modify the drivers/of/address.c to address this problem, but it looks
not so general. I'm not sure you have seen this: https://lkml.org/lkml/2016/1/10/89 .

Regards,
Rongrong