linux-kernel - Re: [PATCH 3/9] irq: convert generic-chip to use irq

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Date:	Thu, 15 Dec 2011 09:39:34 -0700
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Rob Herring <robherring2@...il.com>
Cc:	Shawn Guo <shawn.guo@...escale.com>, Kevin Hilman <khilman@...com>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Tony Lindgren <tony@...mide.com>,
	Linus Walleij <linus.ml.walleij@...il.com>,
	devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	Rob Herring <rob.herring@...xeda.com>,
	Barry Song <baohua.song@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/9] irq: convert generic-chip to use irq_domain

On Thu, Dec 15, 2011 at 9:17 AM, Rob Herring <robherring2@...il.com> wrote:
> On 12/15/2011 09:55 AM, Grant Likely wrote:
>> On Thu, Dec 15, 2011 at 6:56 AM, Rob Herring <robherring2@...il.com> wrote:
>>> Shawn,
>>>
>>> On 12/15/2011 07:39 AM, Rob Herring wrote:
>>>> On 12/14/2011 11:55 PM, Shawn Guo wrote:
>>>>> On Thu, Dec 15, 2011 at 01:25:20PM +0800, Shawn Guo wrote:
>>>>>> On Wed, Dec 14, 2011 at 09:28:52AM -0600, Rob Herring wrote:
>>>>>>> From: Rob Herring <rob.herring@...xeda.com>
>>>>>>>
>>>>>>> Add irq domain support to irq generic-chip. This enables users of
>>>>>>> generic-chip to support dynamic irq assignment needed for DT interrupt
>>>>>>> binding. Users must be converted to use irq_data.hwirq for determining
>>>>>>> local interrupt numbers rather than using the Linux irq number.
>>>>>>>
>>>>>>> irq_base is kept for now as there are a few users of it. Once they
>>>>>>> are converted to use the irq domain, it can be removed.
>>>>>>>
>>>>>>> Signed-off-by: Rob Herring <rob.herring@...xeda.com>
>>>>>>> Cc: Thomas Gleixner <tglx@...utronix.de>
>>>>>>> ---
>>>>>>
>>>>>> Tested-by: Shawn Guo <shawn.guo@...aro.org>
>>>>>>
>>>>> Sorry, I have to take that tag back after I correct my test setup.
>>>>> It does not work for imx5 TZIC case, because the following change
>>>>> I suggested before is missed.
>>>>>
>>>>> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
>>>>> index eb763f7..2a2aac1 100644
>>>>> --- a/kernel/irq/irqdomain.c
>>>>> +++ b/kernel/irq/irqdomain.c
>>>>> @@ -39,7 +39,7 @@ void irq_domain_add(struct irq_domain *domain)
>>>>>                         return;
>>>>>                 }
>>>>>                 d->domain = domain;
>>>>> -               d->hwirq = hwirq;
>>>>> +               d->hwirq = hwirq - domain->hwirq_base;
>>>>
>>>> This is a problem. It entirely defeats the point of hwirq_base and it
>>>> would break the GIC. We need to fix this in the generic irq chip.
>>>>
>>>
>>> I think I found a fix. Can you try 's/d->hwirq/(d->hwirq % 32)/' in
>>> generic-chip.c.
>>
>> Ugh, but that hard codes an assumption that a domain cannot have more
>> that 32 irqs.
>>
>> /me goes to dig into irq_domain code...
>
> No, it hard codes that generic irq chip is 32 interrupts at most which
> is already the case. That's why the TZIC uses 5 generic irq chip instances.

Oops, you're right.  I wasn't paying close enough attention. Sorry for
the noise.

g.
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