[PATCHv2 02/10] ARM: vic: MULTI_IRQ_HANDLER handler

Russell King - ARM Linux linux at arm.linux.org.uk
Fri Nov 4 02:11:34 EST 2011


On Thu, Nov 03, 2011 at 03:03:37PM +0000, Jamie Iles wrote:
> On Thu, Nov 03, 2011 at 01:31:02PM +0000, Russell King - ARM Linux wrote:
> > On Thu, Nov 03, 2011 at 02:00:15PM +0100, Linus Walleij wrote:
> > > On Thu, Nov 3, 2011 at 1:51 PM, Russell King - ARM Linux
> > > <linux at arm.linux.org.uk> wrote:
> > > 
> > > >        stat = readl_relaxed(vic->base + VIC_IRQ_STATUS);
> > > >        while (stat) {
> > > >                while (stat) {
> > > >                        irq = ffs(stat) - 1;
> > > >                        stat &= ~(1 << irq);
> > > >                        handle_irq(irq);
> > > >                }
> > > >                stat = readl_relaxed(vic->base + VIC_IRQ_STATUS);
> > > >        }
> > > >
> > > > This ensures that we process all interrupts found pending before we
> > > > re-check for any new interrupts pending.  Arguably this is a much
> > > > fairer implementation (and may mean if things get irrevokably stuck,
> > > > things like sysrq via the console uart may still work.)
> > > 
> > > I really like the looks of this, Jamie can you do it like that?
> > > 
> > > Maybe some smallish comment about what's going on can be
> > > good for future generations reading that code...
> > 
> > Bear in mind that it gets a little more complex when you have more
> > than one VIC, because the outer loop should be across all VICs.
> 
> OK, so I think what I posted yesterday does that (updated for slightly 
> better naming) and with a description.  In the spirit of fairness 
> iterating over the VIC's this way seemed right to me.

Yes.


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