linux-kernel - Re: [PATCH v2 3/4] irqchip: sifive-plic: Differentiate between PLIC handler and context

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Message-ID: <CAAhSdy2GP+VqfQPJ4Bif81jWJG8v+b9NF-kTNqmjtT_JuOQu+w@mail.gmail.com>
Date:   Fri, 30 Nov 2018 09:25:06 +0530
From:   Anup Patel <anup@...infault.org>
To:     Atish Patra <atish.patra@....com>
Cc:     Palmer Dabbelt <palmer@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Christoph Hellwig <hch@...radead.org>,
        linux-riscv@...ts.infradead.org,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] irqchip: sifive-plic: Differentiate between PLIC
 handler and context

On Fri, Nov 30, 2018 at 7:27 AM Atish Patra <atish.patra@....com> wrote:
>
> On 11/27/18 2:04 AM, Anup Patel wrote:
> > We explicitly differentiate between PLIC handler and context because
> > PLIC context is for given mode of HART whereas PLIC handler is per-CPU
> > software construct meant for handling interrupts from a particular
> > PLIC context.
> >
> > Signed-off-by: Anup Patel <anup@...infault.org>
> > ---
> >   drivers/irqchip/irq-sifive-plic.c | 21 +++++++++++++--------
> >   1 file changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> > index 95b4b92ca9b8..ffd4deaca057 100644
> > --- a/drivers/irqchip/irq-sifive-plic.c
> > +++ b/drivers/irqchip/irq-sifive-plic.c
> > @@ -66,8 +66,8 @@ static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
> >
> >   struct plic_hw {
> >       u32                     nr_irqs;
> > +     u32                     nr_contexts;
> >       u32                     nr_handlers;
> > -     u32                     nr_mapped;
> >       void __iomem            *regs;
> >       struct irq_domain       *irqdomain;
> >   };
> > @@ -191,10 +191,10 @@ static int __init plic_init(struct device_node *node,
> >       if (WARN_ON(!plic.nr_irqs))
> >               goto out_iounmap;
> >
> > -     plic.nr_handlers = of_irq_count(node);
> > -     if (WARN_ON(!plic.nr_handlers))
> > +     plic.nr_contexts = of_irq_count(node);
> > +     if (WARN_ON(!plic.nr_contexts))
> >               goto out_iounmap;
> > -     if (WARN_ON(plic.nr_handlers < num_possible_cpus()))
> > +     if (WARN_ON(plic.nr_contexts < num_possible_cpus()))
> >               goto out_iounmap;
> >
> >       plic.irqdomain = irq_domain_add_linear(node, plic.nr_irqs + 1,
> > @@ -202,7 +202,7 @@ static int __init plic_init(struct device_node *node,
> >       if (WARN_ON(!plic.irqdomain))
> >               goto out_iounmap;
> >
> > -     for (i = 0; i < plic.nr_handlers; i++) {
> > +     for (i = 0; i < plic.nr_contexts; i++) {
> >               struct of_phandle_args parent;
> >               struct plic_handler *handler;
> >               irq_hw_number_t hwirq;
> > @@ -225,6 +225,11 @@ static int __init plic_init(struct device_node *node,
> >
> >               cpu = riscv_hartid_to_cpuid(hartid);
> >               handler = per_cpu_ptr(&plic_handlers, cpu);
> > +             if (handler->present) {
> > +                     pr_warn("handler not available for context %d.\n", i);
> > +                     continue;
> > +             }
> > +
>
> Ahh you have the handler->present check here in this patch. This should
> be in the 2nd patch. This change doesn't match the commit text anyways.

Sure, will do.

>
> Everything else just variable renaming which can be separated.
> nr_handlers->nr_contexts
> nr_mapped->nr_handlers
>

Sure, will update commit text.

Thanks,
Anup