Re: [PATCH v2] sunxi: psci: Fix sunxi_power_switch on sun8i-r40 platform

[Andre Przywara <andre.przywara@arm.com>]

On Sat, 14 May 2022 11:52:01 +0800
Chen-Yu Tsai <wens@kernel.org> wrote:

Hi,

> On Sat, May 14, 2022 at 11:19 AM <qianfanguijin@163.com> wrote:
> >
> > From: qianfan Zhao <qianfanguijin@163.com>
> >
> > linux system will die if we offline one of the cpu on R40 based board:
> > eg: echo 0 > /sys/devices/system/cpu/cpu3/online
> >
> > Fixed sunxi_power_switch based on allwinner lichee 3.10 kernel driver.
> >
> > Signed-off-by: qianfan Zhao <qianfanguijin@163.com>  
> 
> Please add a Fixes tag.
> 
> > ---
> > v2 changes: Fix the commit message, the source code doesn't change.
> >
> >  arch/arm/cpu/armv7/sunxi/psci.c | 24 +++++++++++++++++++-----
> >  1 file changed, 19 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/arm/cpu/armv7/sunxi/psci.c b/arch/arm/cpu/armv7/sunxi/psci.c
> > index 1ac50f558a..63186a9388 100644
> > --- a/arch/arm/cpu/armv7/sunxi/psci.c
> > +++ b/arch/arm/cpu/armv7/sunxi/psci.c
> > @@ -79,8 +79,7 @@ static void __secure __mdelay(u32 ms)
> >  static void __secure clamp_release(u32 __maybe_unused *clamp)
> >  {
> >  #if defined(CONFIG_MACH_SUN6I) || defined(CONFIG_MACH_SUN7I) || \
> > -       defined(CONFIG_MACH_SUN8I_H3) || \
> > -       defined(CONFIG_MACH_SUN8I_R40)
> > +       defined(CONFIG_MACH_SUN8I_H3)
> >         u32 tmp = 0x1ff;
> >         do {
> >                 tmp >>= 1;
> > @@ -88,15 +87,30 @@ static void __secure clamp_release(u32 __maybe_unused *clamp)
> >         } while (tmp);
> >
> >         __mdelay(10);
> > +#elif defined(CONFIG_MACH_SUN8I_R40)
> > +       u8 i, tmp = 0xfe;
> > +
> > +       for (i = 0; i < 5; i++) { /* 0xfe, 0xf8, 0xe0, 0x80, 0x00 */
> > +               writel(tmp, clamp);
> > +               tmp <<= 2;
> > +       }
> > +
> > +       while (0x00 != readl(clamp)) {
> > +               ;
> > +       }
> >  #endif
> >  }
> >
> >  static void __secure clamp_set(u32 __maybe_unused *clamp)
> >  {
> >  #if defined(CONFIG_MACH_SUN6I) || defined(CONFIG_MACH_SUN7I) || \
> > -       defined(CONFIG_MACH_SUN8I_H3) || \
> > -       defined(CONFIG_MACH_SUN8I_R40)
> > +       defined(CONFIG_MACH_SUN8I_H3)
> >         writel(0xff, clamp);
> > +#elif defined(CONFIG_MACH_SUN8I_R40)
> > +       writel(0xff, clamp);
> > +       while (0xff != readl(clamp)) {
> > +               ;
> > +       }
> >  #endif
> >  }
> >
> > @@ -153,7 +167,7 @@ static void __secure sunxi_cpu_set_power(int cpu, bool on)
> >
> >         sunxi_power_switch((void *)cpucfg + SUN8I_R40_PWR_CLAMP(cpu),
> >                            (void *)cpucfg + SUN8I_R40_PWROFF,
> > -                          on, 0);
> > +                          on, cpu);  
> 
> I think this is the only change that is needed. Looking again at the
> R40 user manual, the original code turned off core 0 regardless of
> which core was being brought down.

Reduced the patch to this one change, adjusted and extended the commit
message, and applied to sunxi/master, for v2022.07.

Thanks,
Andre

> 
> Could you give that a try? The power clamp stuff shouldn't change
> much, as the end result is the same. The readback might make a
> difference, but if it does, it should be applied to all SoCs.
> 
> 
> Regards
> ChenYu
> 
> >  }
> >  #else /* ! CONFIG_MACH_SUN7I && ! CONFIG_MACH_SUN8I_R40 */
> >  static void __secure sunxi_cpu_set_power(int cpu, bool on)
> > --
> > 2.25.1
> >