Re: [PATCH v2] Staging: Correct tsi-148 VME interrupt free routine

[Martyn Welch]

Jiri Slaby wrote:
> On 08/05/2009 06:38 PM, Martyn Welch wrote:
>   
> >  	if (tsi148_bridge->irq[level - 1].count == 0) {
> > -		tmp = ioread32be(tsi148_bridge->base + TSI148_LCSR_INTEO);
> > -		tmp &= ~TSI148_LCSR_INTEO_IRQEO[level - 1];
> > -		iowrite32be(tmp, tsi148_bridge->base + TSI148_LCSR_INTEO);
> > -
> >  		tmp = ioread32be(tsi148_bridge->base + TSI148_LCSR_INTEN);
> >  		tmp &= ~TSI148_LCSR_INTEN_IRQEN[level - 1];
> >  		iowrite32be(tmp, tsi148_bridge->base + TSI148_LCSR_INTEN);
> > +
> > +		tmp = ioread32be(tsi148_bridge->base + TSI148_LCSR_INTEO);
> > +		tmp &= ~TSI148_LCSR_INTEO_IRQEO[level - 1];
> > +		iowrite32be(tmp, tsi148_bridge->base + TSI148_LCSR_INTEO);
> >     
>
> I have no idea what the registers do and I suppose it's behind some PCI
> bridge anywhere. If it is not true, ignore the further.
>
> Is it OK that the second write to INTEO doesn't reach the device before
> you set func to NULL? I mean, is it enough to prevent the interrupt
> raising only by twiddling INTEN? Otherwise you need to put some read
> right here to push non-completed writes on bridges (flush posted
> writes). (I mentioned this in the former mail too.)
>   

Yes, this is fine:

TSI148_LCSR_INTEN = Interrupt Enable
TSI148_LCSR_INTEO = Interrupt Output Enable

If an interrupt source is completely disabled, it doesn't matter whether or not it is stopped from generating a PCI interrupt.

Martyn

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Martyn Welch MEng MPhil MIET (Principal Software Engineer)   T:+44(0)1327322748
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