Re: [RFC PATCH v3] irqchip: Add support for Tango interrupt controller

From: Måns Rullgård
Date: Wed Jan 20 2016 - 13:09:29 EST

Marc Gonzalez <marc_gonzalez@xxxxxxxxxxxxxxxx> writes:

> On 20/01/2016 17:38, Måns Rullgård wrote:
>> Marc Gonzalez <marc_gonzalez@xxxxxxxxxxxxxxxx> writes:
>>> On 20/01/2016 17:25, Måns Rullgård wrote:
>>>> Marc Zyngier <marc.zyngier@xxxxxxx> writes:
>>>>> On 20/01/16 16:10, Måns Rullgård wrote:
>>>>>> Marc Zyngier <marc.zyngier@xxxxxxx> 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.
> The two suggestions are over my head at the moment.
> Do you want to submit v4 and have Marc Z take a look?

Done. If this isn't acceptable either, I'm out of ideas that don't end
up being far uglier than anything suggested so far.

Måns Rullgård