Re: [PATCH v2] irqchip: xilinx: Add support for multiple instances

[Marc Zyngier]

On 2020-02-06 09:11, Michal Simek wrote:
> On 06. 02. 20 10:09, Marc Zyngier wrote:
> > On 2020-02-06 07:06, Michal Simek wrote:
> > > On 05. 02. 20 17:53, Marc Zyngier wrote:
> > > > On 2020-02-05 14:05, Mubin Usman Sayyed wrote:
> >
> > [...]
> >
> > > > > Âunsigned int xintc_get_irq(void)
> > > > > Â{
> > > > > -ÂÂÂÂÂÂ unsigned int hwirq, irq = -1;
> > > > > +ÂÂÂÂÂÂ int hwirq, irq = -1;
> > > > >
> > > > > -ÂÂÂÂÂÂ hwirq = xintc_read(IVR);
> > > > > +ÂÂÂÂÂÂ hwirq = xintc_read(primary_intc->base + IVR);
> > > > > ÂÂÂÂÂÂÂ if (hwirq != -1U)
> > > > > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ irq = irq_find_mapping(xintc_irqc->root_domain, 
> > > > > hwirq);
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ irq = irq_find_mapping(primary_intc->root_domain,
> > > > > hwirq);
> > > > >
> > > > > ÂÂÂÂÂÂÂ pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);
> > > >
> > > > I have the ugly feeling I'm reading the same code twice... Surely 
> > > > you
> > > > can
> > > > make these two functions common code.
> > >
> > > I have some questions regarding this.
> > > I have updated one patchset which is adding support for Microblaze 
> > > SMP.
> > > And when I was looking at current wiring of this driver I have 
> > > decided
> > > to change it.
> > >
> > > I have enabled GENERIC_IRQ_MULTI_HANDLER and HANDLE_DOMAIN_IRQ.
> > > This driver calls set_handle_irq(xil_intc_handle_irq)
> > > and MB do_IRQ() call handle_arch_irq()
> > > and IRQ routine here is using handle_domain_irq().
> > >
> > > I would expect that this chained IRQ handler can also use
> > > handle_domain_irq().
> > >
> > > Is that correct understanding?
> >
> > handle_domain_irq() implies that you have a set of pt_regs, 
> > representing
> > the context you interrupted. You can't fake that up, so I can't see 
> > how
> > you use it in a chained context.
>
> ok. What's your recommendation for chained controller? Just go with
> irq_find_mapping?

For now, yes. I have (distant) plans to improve this.

        M.
--
Jazz is not dead. It just smells funny...