lkml.org 
[lkml]   [2011]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] ARM: gic: add OF based initialization
On Mon, Sep 26, 2011 at 03:49:11PM -0500, Rob Herring wrote:
> On 09/26/2011 02:57 PM, Jamie Iles wrote:
> > Hi Rob,
> >
> > On Tue, Sep 20, 2011 at 03:24:04PM -0500, Rob Herring wrote:
> > [...]
> >> +int __init gic_of_init(struct device_node *node, struct device_node *parent)
> >> +{
> >> + void __iomem *cpu_base;
> >> + void __iomem *dist_base;
> >> + int irq;
> >> + struct irq_domain *domain = &gic_data[gic_cnt].domain;
> >> +
> >> + if (WARN_ON(!node))
> >> + return -ENODEV;
> >> +
> >> + dist_base = of_iomap(node, 0);
> >> + WARN(!dist_base, "unable to map gic dist registers\n");
> >> +
> >> + cpu_base = of_iomap(node, 1);
> >> + WARN(!cpu_base, "unable to map gic cpu registers\n");
> >> +
> >> + domain->nr_irq = gic_irq_count(dist_base);
> >> + /* subtract off SGIs. Also subtract off PPIs for secondary GICs */
> >> + if (parent)
> >> + domain->nr_irq -= 32;
> >> + else
> >> + domain->nr_irq -= 16;
> >> +
> >> + domain->irq_base = irq_alloc_descs(-1, 16, domain->nr_irq, numa_node_id());
> >
> > The way I understand irq_alloc_descs() (probably not very well) is that
> > having the irq parameter < 0 and the from parameter 16 means that it
> > needs to find domain->nr_irq descs starting from at least 16. But if
> > the base is greater than 16, does this still work with the gic entry
> > macros as they are?
>
> No, but that would only happen if a platform calls irq_alloc_descs prior
> to this code. The root controller must be initialized first (for other
> reasons as well). There are no calls to irq_alloc_descs in arch/arm.
>
> With the MULTI_IRQ GIC support Marc Z is working on, we could make the
> GIC irq mapping be completely dynamic. Although, there's probably not
> much reason to do so for the root controller.

OK, that makes sense. I think that if you were to do
irq_alloc_descs(16, 16, domain->nr_irqs, num_node_id()) then that will
guarantee the descriptors start from 16 (if they are available) which is
probably nicer.

Jamie


\
 
 \ /
  Last update: 2011-09-26 23:13    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site