On Tue, 27 Mar 2012 11:24:51 -0700, David Daney <david.daney@xxxxxxxxxx> wrote:
> On 03/26/2012 06:56 PM, Rob Herring wrote:
> > On 03/26/2012 02:31 PM, David Daney wrote:
> >> From: David Daney<david.daney@xxxxxxxxxx>
> [...]
> >> +static int octeon_irq_ciu_map(struct irq_domain *d,
> >> + unsigned int virq, irq_hw_number_t hw)
> >> +{
> >> + unsigned int line = hw>> 6;
> >> + unsigned int bit = hw& 63;
> >> +
> >> + if (virq>= 256)
> >> + return -EINVAL;
> >
> > Drop this. You should not care what the virq numbers are.
>
>
> I care that they don't overflow the width of octeon_irq_ciu_to_irq (a u8).
>
> So really I want to say:
>
> if (virq >= (1 << sizeof (octeon_irq_ciu_to_irq[0][0]))) {
> WARN(...);
> return -EINVAL;
> }
>
>
> I need a map external to any one irq_domain. The irq handling code
> handles sources that come from two separate irq_domains, as well as irqs
> that are not part of any domain.
You can get past this limitation by using the struct irq_data .hwirq and
.domain members for the irq ==> hwirq translation, and for hwirq ==>
irq the code should already have the context to know which user it is.
For the irqs that are not covered by an irq_domain, the driver is free
to set the .hwirq value directly. Ultimately however, it will
probably be best to add an irq domain for those users also.
...
Howver, I don't understand where the risk is in overflowing
octeon_irq_ciu_to_irq[][]. From what I can see, the virq value isn't
used at all to calculate the array dereference. line and bit are
calculated from the hwirq value. What am I missing?
g.
