linux-kernel - RE: [PATCH 1/4] soc/fsl/qbman: Check if CPU is offline when initializing portals

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Message-ID: <AM6PR04MB400829AD9740850D5EF93E51EC170@AM6PR04MB4008.eurprd04.prod.outlook.com>
Date:   Mon, 24 Sep 2018 08:54:58 +0000
From:   Madalin-cristian Bucur <madalin.bucur@....com>
To:     Leo Li <leoyang.li@....com>, Roy Pledge <roy.pledge@....com>
CC:     Claudiu Manoil <claudiu.manoil@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Scott Wood <oss@...error.net>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/4] soc/fsl/qbman: Check if CPU is offline when
 initializing portals

> -----Original Message-----
> From: Li Yang [mailto:leoyang.li@....com]
> Sent: Saturday, September 22, 2018 1:15 AM
> To: Madalin-cristian Bucur <madalin.bucur@....com>
> Subject: Re: [PATCH 1/4] soc/fsl/qbman: Check if CPU is offline when
> initializing portals
> 
> On Thu, Sep 20, 2018 at 10:09 AM Madalin Bucur <madalin.bucur@....com>
> wrote:
> >
> > From: Roy Pledge <roy.pledge@....com>
> >
> > If the affine portal for a specific CPU is offline at boot time
> > affine its interrupt to CPU 0. If the CPU is later brought online
> > the hotplug handler will correctly adjust the affinity.
> 
> Although this does provide better compatibility with cpu hotplug, we
> still have a problem.  You are assuming the CPU0 is always online
> which is not the case for arm64.  How about not setting the affinity
> and let the system decide if the dedicated CPU is offline?

I can change the hardcoding of CPU 0 with raw_smp_processor_id().
While we're at it, I'd move the introduced code into a helper function
to avoid duplication:

static inline void dpaa_set_portal_irq_affinity(struct device* dev,
								int cpu, int irq)

> >
> > Signed-off-by: Roy Pledge <roy.pledge@....com>
> > Signed-off-by: Madalin Bucur <madalin.bucur@....com>
> > ---
> >  drivers/soc/fsl/qbman/bman.c | 17 +++++++++++++----
> >  drivers/soc/fsl/qbman/qman.c | 18 +++++++++++++-----
> >  2 files changed, 26 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/soc/fsl/qbman/bman.c b/drivers/soc/fsl/qbman/bman.c
> > index f9485cedc648..2e6e682bf16b 100644
> > --- a/drivers/soc/fsl/qbman/bman.c
> > +++ b/drivers/soc/fsl/qbman/bman.c
> > @@ -562,10 +562,19 @@ static int bman_create_portal(struct bman_portal
> *portal,
> >                 dev_err(c->dev, "request_irq() failed\n");
> >                 goto fail_irq;
> >         }
> > -       if (c->cpu != -1 && irq_can_set_affinity(c->irq) &&
> > -           irq_set_affinity(c->irq, cpumask_of(c->cpu))) {
> > -               dev_err(c->dev, "irq_set_affinity() failed\n");
> > -               goto fail_affinity;
> > +       if (cpu_online(c->cpu) && c->cpu != -1 &&
> > +           irq_can_set_affinity(c->irq)) {
> > +               if (irq_set_affinity(c->irq, cpumask_of(c->cpu))) {
> > +                       dev_err(c->dev, "irq_set_affinity() failed
> %d\n",
> > +                               c->cpu);
> > +                       goto fail_affinity;
> > +               }
> > +       } else {
> > +               /* CPU is offline, direct IRQ to CPU 0 */
> > +               if (irq_set_affinity(c->irq, cpumask_of(0))) {
> > +                       dev_err(c->dev, "irq_set_affinity() cpu 0
> failed\n");
> > +                       goto fail_affinity;
> > +               }
> >         }
> >
> >         /* Need RCR to be empty before continuing */
> > diff --git a/drivers/soc/fsl/qbman/qman.c b/drivers/soc/fsl/qbman/qman.c
> > index ecb22749df0b..7dbcb475a59c 100644
> > --- a/drivers/soc/fsl/qbman/qman.c
> > +++ b/drivers/soc/fsl/qbman/qman.c
> > @@ -935,7 +935,6 @@ static inline int qm_mc_result_timeout(struct
> qm_portal *portal,
> >                         break;
> >                 udelay(1);
> >         } while (--timeout);
> > -
> >         return timeout;
> >  }
> >
> > @@ -1210,10 +1209,19 @@ static int qman_create_portal(struct qman_portal
> *portal,
> >                 dev_err(c->dev, "request_irq() failed\n");
> >                 goto fail_irq;
> >         }
> > -       if (c->cpu != -1 && irq_can_set_affinity(c->irq) &&
> > -           irq_set_affinity(c->irq, cpumask_of(c->cpu))) {
> > -               dev_err(c->dev, "irq_set_affinity() failed\n");
> > -               goto fail_affinity;
> > +       if (cpu_online(c->cpu) && c->cpu != -1 &&
> > +           irq_can_set_affinity(c->irq)) {
> > +               if (irq_set_affinity(c->irq, cpumask_of(c->cpu))) {
> > +                       dev_err(c->dev, "irq_set_affinity() failed
> %d\n",
> > +                               c->cpu);
> > +                       goto fail_affinity;
> > +               }
> > +       } else {
> > +               /* CPU is offline, direct IRQ to CPU 0 */
> > +               if (irq_set_affinity(c->irq, cpumask_of(0))) {
> > +                       dev_err(c->dev, "irq_set_affinity() cpu 0
> failed\n");
> > +                       goto fail_affinity;
> > +               }
> >         }
> >
> >         /* Need EQCR to be empty before continuing */
> > --
> > 2.1.0
> >