Re: [RFC v2 PATCH 07/14] irq: add a new generic IPI reservation code to irq core

[Qais Yousef <qais.yousef@imgtec.com>]

Hi Thomas,

On 10/13/2015 03:38 PM, Qais Yousef wrote:
> On 10/13/2015 02:37 PM, Thomas Gleixner wrote:
>> On Tue, 13 Oct 2015, Qais Yousef wrote:
>>
>>> +    if (domain == NULL)
>>> +        domain = irq_default_domain; /* need a separate 
>>> ipi_default_domain? */
>> No tail comments please.
>>
>> We should neither use irq_default_domain nor have an
>> ipi_default_domain.
>
> OK though I understood that you were OK with using the 
> irq_default_domain.
>
> This means that arch code must parse the DT for an IPI domain. I think 
> I've seen arch code using the root FDT to search for a specific node. 
> I'll try to do something similar to search for an IPI domain.

I'm having an issue here. I made the arch code look for an IPI domain 
but we have some platforms on MIPS that don't support device tree. I 
can't find how I can go away with that without using irq_default_domain.

Also irq_default_domain is understandably only visible within irqdomain 
code, so I can't make the arch code fallback to passing 
irq_default_domain if the platform doesn't support DT.

Are you OK with keeping this in irq_reserve_ipi()? Alternatively I could 
modify irq_find_host(), which I'm using to find the IPI domain, return 
irq_default_domain() if the passed node is NULL.

Or maybe there's a better option I couldn't think of?

Thanks,
Qais