[PATCH 1/2] ARM: gic: add irq_domain support
Grant Likely
grant.likely at secretlab.ca
Fri Sep 30 10:27:51 EST 2011
On Thu, Sep 29, 2011 at 04:02:44PM -0500, Rob Herring wrote:
> On 09/29/2011 12:15 PM, Grant Likely wrote:
> > On Wed, Sep 28, 2011 at 10:53:55PM -0500, Rob Herring wrote:
> >> From: Rob Herring <rob.herring at 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.
>
> I started out exactly this way removing irq_offset. The problem is the
> core irq domain code assumes that hwirq starts at 0, but for the gic it
> starts at 16 or 32.
>
> It could be fixed in the domain core, but that would effectively mean
> moving irq_offset into the core.
Fix irq_domain. If it cannot handle this trivial case, then it won't
be able to handle the complex powerpc use cases.
g.
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