Messages in this thread | | | From | Guo Ren <> | Date | Mon, 25 Oct 2021 21:33:27 +0800 | Subject | Re: [PATCH V5 3/3] irqchip/sifive-plic: Fixup thead,c900-plic request_threaded_irq with ONESHOT |
| |
On Mon, Oct 25, 2021 at 6:48 PM Marc Zyngier <maz@kernel.org> wrote: > > On Sun, 24 Oct 2021 02:33:03 +0100, > guoren@kernel.org wrote: > > > > From: Guo Ren <guoren@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 thead,c900-plic couldn't complete masked irq source which > > has been disabled in enable register. Add thead_plic_chip which fix up > > c906-plic irq source completion problem by unmask/mask wrapper. > > > > Here is the description of Interrupt Completion in PLIC spec [1]: > > > > 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. > > Given this bit of the spec... > > > +static void plic_thead_irq_eoi(struct irq_data *d) > > +{ > > + struct plic_handler *handler = this_cpu_ptr(&plic_handlers); > > + > > + 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); > > + } > > +} > > + > > ... it isn't obvious to me why this cannot happen on an SiFive PLIC. I'm not sure about SiFive PLIC. Maybe they didn't follow that to implement.
> > And it isn't only for threaded interrupts in oneshot mode. Any driver > can mask an interrupt from its handler after having set the > IRQ_DISABLE_UNLAZY flag, and the interrupt would need the exact same > treatment. Thx for mentioned here, and I'll add it in the comment of next version patch.
> > M. > > -- > Without deviation from the norm, progress is not possible.
-- Best Regards Guo Ren
ML: https://lore.kernel.org/linux-csky/
| |