Re: [PATCH] xen/arm: Correctly read the GICv3 Re-Distributor stride

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-09-30 at 11:29 +0000, Shameerali Kolothum Thodi wrote:
> 
> > -----Original Message-----
> > From: Ian Campbell [mailto:ian.campbell@citrix.com]
> > Sent: 30 September 2015 12:04
> > To: Shameerali Kolothum Thodi; xen-devel@lists.xenproject.org
> > Cc: julien.grall@citrix.com; vijaya.kumar@caviumnetworks.com
> > Subject: Re: [PATCH] xen/arm: Correctly read the GICv3 Re-Distributor
> > stride
> > 
> > On Wed, 2015-09-30 at 11:54 +0100, Shameerali Kolothum Thodi wrote:
> > > The GICv3 driver read a 32 bit value for the re-distributor stride,
> > > but the dts binding is a two-cell property.
> > 
> > The binding doc I have says:
> > 
> > - redistributor-stride : If using padding pages, specifies the stride
> >   of consecutive redistributors. Must be a multiple of 64kB.
> > 
> > i.e. it doesn't say anything about the size. The _example_ is 2 cells,
> > but I don't think that is normative.
> > 
> > Unless you can point to a bindings update which specifies strictly two
> > cells then I think the right answer is the use dt_read_number.
> 
> You are right. The binding text is not clear. But Linux gic driver from the
> beginning is using the 64 bit value.

The Linux gic driver is also not a normative declaration of the spec.

I think the spec needs to be clarified and then Linux and/or Xen need to be
fixed to follow the spec.

Ian.