Messages in this thread | | | Date | Thu, 29 Sep 2011 12:15:40 -0500 | From | Grant Likely <> | Subject | Re: [PATCH 1/2] ARM: gic: add irq_domain support |
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On Wed, Sep 28, 2011 at 10:53:55PM -0500, Rob Herring wrote: > From: Rob Herring <rob.herring@calxeda.com> > > Convert the gic interrupt controller to use irq domains in preparation > for device-tree binding and MULTI_IRQ. This allows for translation between > GIC interrupt IDs and Linux irq numbers. > > The meaning of irq_offset has changed. It now is just the number of skipped > GIC interrupt IDs for the controller. It will be 16 for primary GIC and 32 > for secondary GICs.
[...]
> /* > @@ -81,7 +82,7 @@ static inline unsigned int gic_irq(struct irq_data *d) > */ > static void gic_mask_irq(struct irq_data *d) > { > - u32 mask = 1 << (d->irq % 32); > + u32 mask = 1 << (gic_irq(d) % 32);
This can probably change simply to d->hwirq if irq_offset is eliminated as I describe below.
> void __init gic_init(unsigned int gic_nr, unsigned int irq_start, > void __iomem *dist_base, void __iomem *cpu_base) > { > struct gic_chip_data *gic; > + struct irq_domain *domain; > + int gic_irqs; > > BUG_ON(gic_nr >= MAX_GIC_NR); > > gic = &gic_data[gic_nr]; > + domain = &gic->domain; > gic->dist_base = dist_base; > gic->cpu_base = cpu_base; > - gic->irq_offset = (irq_start - 1) & ~31; > > - if (gic_nr == 0) > + /* > + * For primary GICs, skip over SGIs. > + * For secondary GICs, skip over PPIs, too. > + */ > + if (gic_nr == 0) { > gic_cpu_base_addr = cpu_base; > + gic->irq_offset = 16; > + irq_start = (irq_start & ~31) + 16;
With the switch to irq_domain, there should no longer be any need for a ~31 mask on the irq_start number. Yes, you'll want to make sure that it doesn't allocate below irq 16, but the driver should completely use the irq_domain to manage the mapping from linux-irq number to hwirq number. The ~31 mask appears to have been an optimization to quickly calculate hwirq number from the linux one, but that value is now found in irq_data->hwirq.
irq_offset could almost be dropped entirely outside of probe because it no longer matters. Instead, populate the to_irq() hook so that the hwirq value gets set correctly from the outset.
It would be better in general to have a consistent view of what the hwirq number means regardless of if it is a root GIC.
g.
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