Re: [PATCHv3 2/6] irqchip/irq-pruss-intc: Add a PRUSS irqchip driver for PRUSS interrupts

[Marc Zyngier]

On 2020-07-05 14:26, Grzegorz Jaszczyk wrote:
> On Sat, 4 Jul 2020 at 11:39, Marc Zyngier <maz@xxxxxxxxxx> wrote:
> > On 2020-07-03 15:28, Grzegorz Jaszczyk wrote:

[...]

> > It still begs the question: if the HW can support both edge and level
> > triggered interrupts, why isn't the driver supporting this diversity?
> > I appreciate that your HW may only have level interrupts so far, but
> > what guarantees that this will forever be true? It would imply a 
> > change
> > in the DT binding, which isn't desirable.
>
> Ok, I've got your point. I will try to come up with something later
> on. Probably extending interrupt-cells by one and passing interrupt
> type will be enough for now. Extending this driver to actually support
> it can be handled later if needed. Hope it works for you.

Writing a set_type callback to deal with this should be pretty easy.
Don't delay doing the right thing.

[...]

> > >> > +             hwirq = hipir & GENMASK(9, 0);
> > >> > +             virq = irq_linear_revmap(intc->domain, hwirq);
> > >>
> > >> And this is where I worry. You seems to have a single irqdomain
> > >> for all the muxes. Are you guaranteed that you will have no
> > >> overlap between muxes? And please use irq_find_mapping(), as
> > >> I have top-secret plans to kill irq_linear_revmap().
> > >
> > > Regarding irq_find_mapping - sure.
> > >
> > > Regarding irqdomains:
> > > It is a single irqdomain since the hwirq (system event) can be mapped
> > > to different irq_host (muxes). Patch #6
> > > https://lkml.org/lkml/2020/7/2/616 implements and describes how input
> > > events can be mapped to some output host interrupts through 2 levels
> > > of many-to-one mapping i.e. events to channel mapping and channels to
> > > host interrupts. Mentioned implementation ensures that specific system
> > > event (hwirq) can be mapped through PRUSS specific channel into a
> > > single host interrupt.
> >
> > Patch #6 is a nightmare of its own, and I haven't fully groked it yet.
> > Also, this driver seems to totally ignore the 2-level routing. Where
> > is it set up? map/unmap in this driver do exactly *nothing*, so
> > something somewhere must set it up.
>
> The map/unmap is updated in patch #6 and it deals with those 2-level
> routing setup. Map is responsible for programming the Channel Map
> Registers (CMRx) and Host-Interrupt Map Registers (HMRx) basing on
> provided configuration from the one parsed in the xlate function.
> Unmap undo whatever was done on the map. More details can be found in
> patch #6.
>
> Maybe it would be better to squash patch #6 with this one so it would
> be less confusing. What is your advice?

So am I right in understanding that without patch #6, this driver does
exactly nothing? If so, it has been a waste of review time.

Please split patch #6 so that this driver does something useful
for Linux, without any of the PRU interrupt routing stuff. I want
to see a Linux-only driver that works and doesn't rely on any other
exotic feature.

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