linux-kernel - Re: [PATCH 4/9] sh: intc: Drop the use of irq_create_identity

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Message-ID: <87im4zpnv2.wl-maz@kernel.org>
Date:   Tue, 06 Apr 2021 14:02:41 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Linux-sh list <linux-sh@...r.kernel.org>,
        Daniel Mack <daniel@...que.org>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Michael Ellerman <mpe@...erman.id.au>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 4/9] sh: intc: Drop the use of irq_create_identity_mapping()

On Tue, 06 Apr 2021 11:32:13 +0100,
Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> 
> Hi Marc,
> 
> On Tue, Apr 6, 2021 at 11:44 AM Marc Zyngier <maz@...nel.org> wrote:
> > Instead of playing games with using irq_create_identity_mapping()
> > and irq_domain_associate(), drop the use of the former and only
> > use the latter, together with the allocation of the irq_desc
> > as needed.
> >
> > It doesn't make the code less awful, but at least the intent
> > is clearer.
> >
> > Signed-off-by: Marc Zyngier <maz@...nel.org>
> 
> Thanks for your patch!
> 
> > --- a/drivers/sh/intc/core.c
> > +++ b/drivers/sh/intc/core.c
> > @@ -179,6 +179,23 @@ static unsigned int __init save_reg(struct intc_desc_int *d,
> >         return 0;
> >  }
> >
> > +static bool __init intc_map(struct irq_domain *domain, int irq)
> > +{
> > +       int res;
> 
> warning: unused variable ‘res’ [-Wunused-variable]
> 
> > +
> > +       if (!irq_to_desc(irq) && irq_alloc_desc_at(irq, NUMA_NO_NODE) != irq) {
> > +               pr_err("uname to allocate IRQ %d\n", irq);
> > +               return false;
> > +       }
> > +
> > +       if (irq_domain_associate(domain, irq, irq)) {
> > +               pr_err("domain association failure\n");
> > +               return false;
> > +       }
> > +
> > +       return true;
> > +}
> > +
> >  int __init register_intc_controller(struct intc_desc *desc)
> >  {
> >         unsigned int i, k, smp;
> > @@ -316,19 +333,8 @@ int __init register_intc_controller(struct intc_desc *desc)
> 
> warning: unused variable ‘res’ [-Wunused-variable]

Ah, thanks for spotting these.

> 
> >                 if (!vect->enum_id)
> >                         continue;
> >
> > -               res = irq_create_identity_mapping(d->domain, irq);
> 
> 
> > -               if (unlikely(res)) {
> > -                       if (res == -EEXIST) {
> > -                               res = irq_domain_associate(d->domain, irq, irq);
> > -                               if (unlikely(res)) {
> > -                                       pr_err("domain association failure\n");
> > -                                       continue;
> > -                               }
> > -                       } else {
> > -                               pr_err("can't identity map IRQ %d\n", irq);
> > -                               continue;
> > -                       }
> > -               }
> > +               if (!intc_map(d->domain, irq))
> > +                       continue;
> >
> >                 intc_irq_xlate_set(irq, vect->enum_id, d);
> >                 intc_register_irq(desc, d, vect->enum_id, irq);
> 
> Otherwise this seems to work fine on real hardware (landisk) and qemu
> (rts7751r2d).  I did verify that the new function intc_map() is called.
> 
> Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>

Awesome, thanks Geert.

	M.

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