Re: [PATCH] of/irq: Add a quirk for controllers with their own definition of interrupt-map

[Marc Zyngier <maz@kernel.org>]

On Mon, 22 Nov 2021 13:10:32 +0000,
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> 
> Hi Marc,
> 
> On Mon, Nov 22, 2021 at 11:30 AM Marc Zyngier <maz@kernel.org> wrote:
> > Since 041284181226 ("of/irq: Allow matching of an interrupt-map local
> > to an interrupt controller"), a handful of interrupt controllers have
> > stopped working correctly. This is due to the DT exposing a non-sensical
> > interrupt-map property, and their drivers relying on the kernel ignoring
> > this property.
> >
> > Since we cannot realistically fix this terrible behaviour, add a quirk
> > for the limited set of devices that have implemented this monster,
> > and document that this is a pretty bad practice.
> >
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: John Crispin <john@phrozen.org>
> > Cc: Biwen Li <biwen.li@nxp.com>
> > Cc: Chris Brandt <chris.brandt@renesas.com>
> > Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> 
> Thanks for your patch!
> 
> > --- a/drivers/of/irq.c
> > +++ b/drivers/of/irq.c
> > @@ -76,6 +76,36 @@ struct device_node *of_irq_find_parent(struct device_node *child)
> >  }
> >  EXPORT_SYMBOL_GPL(of_irq_find_parent);
> >
> > +/*
> > + * These interrupt controllers abuse interrupt-map for unspeakable
> > + * reasons and rely on the core code to *ignore* it (the drivers do
> > + * their own parsing of the property).
> > + *
> > + * If you think of adding to the list for something *new*, think
> > + * again. There is a high chance that you will be sent back to the
> > + * drawing board.
> > + */
> > +static const char * const of_irq_imap_abusers[] = {
> > +       "CBEA,platform-spider-pic",
> > +       "sti,platform-spider-pic",
> > +       "realtek,rtl-intc",
> > +       "fsl,ls1021a-extirq",
> > +       "fsl,ls1043a-extirq",
> > +       "fsl,ls1088a-extirq",
> > +       "renesas,rza1-irqc",
> > +};
> 
> Are you sure "renesas,rza1-irqc" handles this wrong? How should it
> be handled instead? I read the other thread[1], but didn't became
> any wiser: interrupts are mapped one-to-one with the RZ/A1 IRQC.
> 
> In both v5.15 and v5.16-rc1, interrupts seem to work fine on RSK+RZA1
> and RZA2MEVB, both with gpio-keys and when used as a wake-up interrupt.

This is odd. 5.16-rc1 should actively breaks the behaviour, as each
interrupt is directly routed to the GIC. Here's an extract of the DT
for r7s9210:

    interrupt-map = <0 0 &gic GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>,
                    <1 0 &gic GIC_SPI 5 IRQ_TYPE_LEVEL_HIGH>,
                    <2 0 &gic GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
                    <3 0 &gic GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
                    <4 0 &gic GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
                    <5 0 &gic GIC_SPI 9 IRQ_TYPE_LEVEL_HIGH>,
                    <6 0 &gic GIC_SPI 10 IRQ_TYPE_LEVEL_HIGH>,
                    <7 0 &gic GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>;

I expect v5.16-rc1 to honour the routing described here and not
involve rza1-irqc, because that's what the DT says.

> With this patch applied, I see double keypresses with evtest: when
> pressing a key, I get a key-down event, immediately followed by a
> key-up event. When releasing the key, I again get two events.
> 
> Good (v5.15 or v5.16-rc1):
> 
>     Event: time 1637585631.288990, type 1 (EV_KEY), code 2 (KEY_1), value 1
>     Event: time 1637585631.288990, -------------- SYN_REPORT ------------
>     Event: time 1637585631.499924, type 1 (EV_KEY), code 2 (KEY_1), value 0
>     Event: time 1637585631.499924, -------------- SYN_REPORT ------------
> 
> Bad (v5.16-rc1 + this patch):
> 
>     Event: time 1637585341.946647, type 1 (EV_KEY), code 2 (KEY_1), value 1
>     Event: time 1637585341.946647, -------------- SYN_REPORT ------------
>     Event: time 1637585341.960256, type 1 (EV_KEY), code 2 (KEY_1), value 0
>     Event: time 1637585341.960256, -------------- SYN_REPORT ------------
>     Event: time 1637585342.146775, type 1 (EV_KEY), code 2 (KEY_1), value 1
>     Event: time 1637585342.146775, -------------- SYN_REPORT ------------
>     Event: time 1637585342.160092, type 1 (EV_KEY), code 2 (KEY_1), value 0
>     Event: time 1637585342.160092, -------------- SYN_REPORT ------------

Is there any chance you could trace whether rza1-irqc gets called at
all when setting up and handling the interrupt?

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.