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From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= <mans@mansr.com>
To: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>, Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
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        Sebastian Frias <sf84@laposte.net>
Subject: Re: [RFC PATCH v3] irqchip: Add support for Tango interrupt controller
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Date: Wed, 20 Jan 2016 16:38:32 +0000
In-Reply-To: <569FB7A9.9080309@sigmadesigns.com> (Marc Gonzalez's message of
	"Wed, 20 Jan 2016 17:36:57 +0100")
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Marc Gonzalez <marc_gonzalez@sigmadesigns.com> writes:

> On 20/01/2016 17:25, Måns Rullgård wrote:
>
>> Marc Zyngier <marc.zyngier@arm.com> writes:
>> 
>>> On 20/01/16 16:10, Måns Rullgård wrote:
>>>
>>>> Marc Zyngier <marc.zyngier@arm.com> writes:
>>>>
>>>>>> +	if (of_property_read_u32(node, "reg", &ctl))
>>>>>> +		panic("%s: failed to get reg base", node->name);
>>>>>> +
>>>>>> +	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
>>>>>> +	chip->ctl = ctl;
>>>>>> +	chip->base = base;
>>>>
>>>> As I said before, this assumes the outer DT node uses a ranges
>>>> property.  Normally reg properties work the same whether they specify an
>>>> offset within an outer "ranges" or have a full address directly.  It
>>>> would be easy enough to make this work with either, so I don't see any
>>>> reason not to.
>>>
>>> Yup, that is a good point. I guess Marc can address this in the next
>>> round, since we need a DT binding anyway.
>> 
>> I'd suggest using of_address_to_resource() on both nodes and subtracting
>> the start addresses returned.
>
> For my own reference, Marc Zyngier suggested:
> "you should use of_iomap to map the child nodes, and not mess with
> the parent one."

That's going to get very messy since the generic irqchip code needs all
the registers as offsets from a common base address.

-- 
Måns Rullgård