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Message-ID: <20151012135350.0f127fa3@xhacker>
Date: Mon, 12 Oct 2015 13:53:50 +0800
From: Jisheng Zhang <jszhang@...vell.com>
To: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
CC: <linux@....linux.org.uk>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND 1/2] arm: berlin: use non-self-cleared reset
register to reset cpu
Dear Sebastian,
On Mon, 21 Sep 2015 10:18:25 +0800
Jisheng Zhang <jszhang@...vell.com> wrote:
> Dear Sebastian,
>
> On Sun, 20 Sep 2015 20:04:01 +0200
> Sebastian Hesselbarth <sebastian.hesselbarth@...il.com> wrote:
>
> > On 14.09.2015 08:47, Jisheng Zhang wrote:
> > > In Berlin SoCs, there are two kinds of cpu reset control registers: the
> > > first one's corresponding bits will be self-cleared after some cycles,
> > > while the second one's bits won't. Previously the first kind of reset
> > > control register is used, this patch uses the second kind one to prepare
> > > for the next hotplug commit.
> > >
> > > Signed-off-by: Jisheng Zhang <jszhang@...vell.com>
> > > ---
> > > arch/arm/mach-berlin/platsmp.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c
> > > index 34a3753..bde327b 100644
> > > --- a/arch/arm/mach-berlin/platsmp.c
> > > +++ b/arch/arm/mach-berlin/platsmp.c
> > > @@ -17,7 +17,7 @@
> > > #include <asm/smp_plat.h>
> > > #include <asm/smp_scu.h>
> > >
> > > -#define CPU_RESET 0x00
> > > +#define CPU_RESET 0x20
> >
> > Jisheng,
> >
> > I am fine with the patch itself, except that I'd like to rather
> > rename the 0x00-register to CPU_RESET_SC with a comment about
> > the self-clearing nature. The 0x20-register would then be named
> > CPU_RESET_NON_SC and used the way you propose.
>
> Good idea. And such comment would let people understand why do we change
> as that.
>
> >
> > Are you fine with me naming the registers accordingly while
> > applying the patches?
>
> Sure, I'm fine. Thank you very much.
I found these two patches are missing in your round 1 berlin pull request. Do
you want me send v2 patches applying the above changes you suggested?
Thanks,
Jisheng
>
> >
> > Sebastian
> >
> > > #define RESET_VECT 0x00
> > > #define SW_RESET_ADDR 0x94
> > > @@ -31,6 +31,8 @@ static inline void berlin_perform_reset_cpu(unsigned int cpu)
> > > u32 val;
> > >
> > > val = readl(cpu_ctrl + CPU_RESET);
> > > + val &= ~BIT(cpu_logical_map(cpu));
> > > + writel(val, cpu_ctrl + CPU_RESET);
> > > val |= BIT(cpu_logical_map(cpu));
> > > writel(val, cpu_ctrl + CPU_RESET);
> > > }
> > >
> >
>
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