From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH v2 08/15] xen/arm: use device api to detect
	GIC version
Date: Thu, 10 Apr 2014 10:05:28 +0100
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To: Julien Grall <julien.grall@linaro.org>
Cc: Vijay Kilari <vijay.kilari@gmail.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Prasun Kapoor <Prasun.Kapoor@caviumnetworks.com>, Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>, xen-devel@lists.xen.org, Stefano Stabellini <stefano.stabellini@citrix.com>
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On Wed, 2014-04-09 at 15:32 +0100, Julien Grall wrote:
> On 04/09/2014 03:28 PM, Vijay Kilari wrote:
> >>> +
> >>> +    dt_for_each_device_node(dt_host, node)
> >>> +    {
> >>> +        rc = device_init(node, DEVICE_GIC, NULL);
> >>> +        if ( !rc )
> >>> +            num_gics++;
> >>
> >> Xen only supports a single GIC for now. You have to initialized the
> >> correct one (see dt_find_interrupt_controller).
> > 
> > dt_find_interrupt_controller expects compatibility string as below to fetch
> > the gic node which can be passed to device_init().
> > 
> > static const struct dt_device_match gic_ids[] __initconst =
> >     {
> >         DT_MATCH_GIC,
> >         { /* sentinel */ },
> >     };
> > 
> > In such case, generic driver has to pass compatibility strings of both
> > GIC v3 & GIC v2 to find the node in dt. Is this ok?
> > 
> > Other way is to break when num_gics = 1 when it finds the first gic node.
> 
> Why can't you modify dt_find_interrupt_controller? Or even better, take
> the code from it and use it directly in your function...

The patch here looks like a pretty natural use of the DT device API to
me, I think all that is needed is for gicv2_init to call
dt_get_parent(np) and skip any non-root gic with a warning message and
return error.

Something should also check for the "interrupt-controller" property,
either the inner or outer init function.

Ian.