[PATCH V6] irqchip/sifive-plic: Fixup EOI failed when masked

[Guo Ren]

On Mon, Nov 1, 2021 at 9:47 PM Nikita Shubin <nikita.shubin at maquefel.me> wrote:
>
> On Mon,  1 Nov 2021 21:17:36 +0800
> guoren at kernel.org wrote:
>
> Hi Guo Ren,
>
> Thank you for your patch.
>
> May be it should be applied to stable ?
Yes, I would Cc stable next.

>
> Tested-by: Nikita Shubin <nikita.shubin at maquefel.me>
>
> > From: Guo Ren <guoren at linux.alibaba.com>
> >
> > When using "devm_request_threaded_irq(,,,,IRQF_ONESHOT,,)" in the
> > driver, only the first interrupt could be handled, and continue irq
> > is blocked by hw. Because the riscv plic couldn't complete masked irq
> > source which has been disabled in enable register. The bug was
> > firstly reported in [1].
> >
> > Here is the description of Interrupt Completion in PLIC spec [2]:
> >
> > The PLIC signals it has completed executing an interrupt handler by
> > writing the interrupt ID it received from the claim to the
> > claim/complete register. The PLIC does not check whether the
> > completion ID is the same as the last claim ID for that target. If
> > the completion ID does not match an interrupt source that is
> > currently enabled for the target, the ^^ ^^^^^^^^^ ^^^^^^^
> > completion is silently ignored.
> >
> > [1]
> > http://lists.infradead.org/pipermail/linux-riscv/2021-July/007441.html
> > [2]
> > https://github.com/riscv/riscv-plic-spec/blob/8bc15a35d07c9edf7b5d23fec9728302595ffc4d/riscv-plic.adoc
> >
> > Reported-by: Vincent Pelletier <plr.vincent at gmail.com>
> > Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> > Cc: Anup Patel <anup at brainfault.org>
> > Cc: Thomas Gleixner <tglx at linutronix.de>
> > Cc: Marc Zyngier <maz at kernel.org>
> > Cc: Palmer Dabbelt <palmer at dabbelt.com>
> > Cc: Atish Patra <atish.patra at wdc.com>
> > Cc: Nikita Shubin <nikita.shubin at maquefel.me>
> > Cc: incent Pelletier <plr.vincent at gmail.com>
> >
> > ---
> >
> > Changes since V6:
> >  - Propagate to plic_irq_eoi for all riscv,plic by Nikita Shubin
> >  - Remove thead related codes
> >
> > Changes since V5:
> >  - Move back to mask/unmask
> >  - Fixup the problem in eoi callback
> >  - Remove allwinner,sun20i-d1 IRQCHIP_DECLARE
> >  - Rewrite comment log
> >
> > Changes since V4:
> >  - Update comment by Anup
> >
> > Changes since V3:
> >  - Rename "c9xx" to "c900"
> >  - Add sifive_plic_chip and thead_plic_chip for difference
> >
> > Changes since V2:
> >  - Add a separate compatible string "thead,c9xx-plic"
> >  - set irq_mask/unmask of "plic_chip" to NULL and point
> >    irq_enable/disable of "plic_chip" to plic_irq_mask/unmask
> >  - Add a detailed comment block in plic_init() about the
> >    differences in Claim/Completion process of RISC-V PLIC and C9xx
> >    PLIC.
> > ---
> >  drivers/irqchip/irq-sifive-plic.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/irqchip/irq-sifive-plic.c
> > b/drivers/irqchip/irq-sifive-plic.c index cf74cfa82045..259065d271ef
> > 100644 --- a/drivers/irqchip/irq-sifive-plic.c
> > +++ b/drivers/irqchip/irq-sifive-plic.c
> > @@ -163,7 +163,13 @@ static void plic_irq_eoi(struct irq_data *d)
> >  {
> >       struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
> >
> > -     writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
> > +     if (irqd_irq_masked(d)) {
> > +             plic_irq_unmask(d);
> > +             writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
> > +             plic_irq_mask(d);
> > +     } else {
> > +             writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
> > +     }
> >  }
> >
> >  static struct irq_chip plic_chip = {
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/