[PATCH] ARM: rockchip: keep reset control around

[Philipp Zabel]

On Fr, 2026-05-22 at 09:20 +0200, Heiko Stuebner wrote:
> Am Donnerstag, 21. Mai 2026, 23:09:15 Mitteleuropäische Sommerzeit schrieb Heiko Stuebner:
> > Do not put the reset control, retain exclusive control over it.
> > After turning on a CPU, the corresponding reset line must stay
> > deasserted.
> > 
> > This also avoids calling reset_control_put() before workqueues
> > are operational.
> > 
> > Fixes: 78ebbff6d1a0 ("reset: handle removing supplier before consumers")
> > Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> > Tested-by: Steven Price <steven.price at arm.com>
> > Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> > ---
> >  arch/arm/mach-rockchip/platsmp.c | 16 ++++++++++------
> >  1 file changed, 10 insertions(+), 6 deletions(-)
> > 
> > diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
> > index f432d22bfed8..f659d894bfae 100644
> > --- a/arch/arm/mach-rockchip/platsmp.c
> > +++ b/arch/arm/mach-rockchip/platsmp.c
> > @@ -34,6 +34,7 @@ static int ncores;
> >  
> >  static struct regmap *pmu;
> >  static int has_pmu = true;
> > +static struct reset_control *cpu_rstc[4];
> 
> After sleeping on that, this should be cpu_rstc[5];
> 
> Coretx-A9 SoCs need to enable the SCU power-domain which thankfully
> sits at index 4 of the power-domain register.
> 
> So while we (already) expect no reset control for that, we need at least
> make sure, it's not reading into undefined memory

The access in pmu_set_power_domain() is gated by
(pd < ARRAY_SIZE(cpu_rstc)). And ncores in rockchip_smp_prepare_cpus()
can not be larger than 4.

> and thus need that empty field in the array.

We could drop the ARRAY_SIZE check and add a placeholder to the array,
but it would need to be set to ERR_PTR(-EINVAL). Otherwise we'd have to
replace all the IS_ERR(rstc) checks as well. I think that would be a
good follow-up change.

regards
Philipp