linux-kernel - Re: [PATCH v3 7/7] ARM: sun8i: smp: Remove the disabling of CPU0

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Message-ID: <20180219115031.77a0a1ca@dell-desktop.home>
Date:   Mon, 19 Feb 2018 11:50:31 +0100
From:   Mylène Josserand <mylene.josserand@...tlin.com>
To:     Maxime Ripard <maxime.ripard@...tlin.com>
Cc:     wens@...e.org, linux@...linux.org.uk, robh+dt@...nel.org,
        mark.rutland@....com, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        clabbe.montjoie@...il.com, thomas.petazzoni@...tlin.com,
        quentin.schulz@...tlin.com
Subject: Re: [PATCH v3 7/7] ARM: sun8i: smp: Remove the disabling of CPU0

Hi,

On Mon, 19 Feb 2018 09:54:08 +0100
Maxime Ripard <maxime.ripard@...tlin.com> wrote:

> On Mon, Feb 19, 2018 at 09:18:37AM +0100, Mylène Josserand wrote:
> > On sun8i-a63t, hotplug CPU for CPU0 is currently not working.
> > Remove the possibility to disable CPU0 only for sun8i-a83t.
> > 
> > Signed-off-by: Mylène Josserand <mylene.josserand@...tlin.com>
> > ---
> >  arch/arm/mach-sunxi/mc_smp.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/mach-sunxi/mc_smp.c b/arch/arm/mach-sunxi/mc_smp.c
> > index fec592bf68b4..69d5ae5b3d72 100644
> > --- a/arch/arm/mach-sunxi/mc_smp.c
> > +++ b/arch/arm/mach-sunxi/mc_smp.c
> > @@ -661,8 +661,12 @@ static int sunxi_mc_smp_cpu_kill(unsigned int l_cpu)
> >  	return !ret;
> >  }
> >  
> > -static bool sunxi_mc_smp_cpu_can_disable(unsigned int __unused)
> > +static bool sunxi_mc_smp_cpu_can_disable(unsigned int cpu)
> >  {
> > +	/* CPU0 hotplug handled only for sun9i */
> > +	if (of_machine_is_compatible("allwinner,sun8i-a83t"))
> > +		if (cpu == 0)
> > +			return false;  
> 
> This also means that you have a window in your patch sequence where
> you can disable the CPU0 on the A83t. This patch should be earlier.

It is true.
With your comment in my first patch, it will be done earlier.

Thanks,

Mylène

-- 
Mylène Josserand, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com