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

From: Qais Yousef
Date: Thu Oct 29 2015 - 06:40:35 EST


On 10/28/2015 03:46 PM, Qais Yousef wrote:
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?

I think I can fix this in the GIC driver by using my own irq_domain->ops->match() function to ignore when of_node is NULL to cope with platforms without DT.

Sorry for the noise.

Thanks,
Qais
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/