Re: [PATCH v5 3/7] pmdomain: rockchip: forward rockchip_do_pmu_set_power_domain errors

[Sebastian Reichel]

Hi,

On Thu, Dec 12, 2024 at 12:26:42PM +0100, Ulf Hansson wrote:
> On Thu, 12 Dec 2024 at 00:11, Peter Geis <pgwipeout@xxxxxxxxx> wrote:
> > On Wed, Dec 11, 2024 at 3:46 PM Sebastian Reichel
> > <sebastian.reichel@xxxxxxxxxxxxx> wrote:
> > > On Wed, Dec 11, 2024 at 02:53:34PM -0500, Peter Geis wrote:
> > > > On Wed, Dec 11, 2024 at 9:32 AM Sebastian Reichel
> > > > <sebastian.reichel@xxxxxxxxxxxxx> wrote:
> > > > >
> > > > > Currently rockchip_do_pmu_set_power_domain prints a warning if there
> > > > > have been errors turning on the power domain, but it does not return
> > > > > any errors and rockchip_pd_power() tries to continue setting up the
> > > > > QOS registers. This usually results in accessing unpowered registers,
> > > > > which triggers an SError and a full system hang.
> > > > >
> > > > > This improves the error handling by forwarding the error to avoid
> > > > > kernel panics.
> > > >
> > > > I think we should merge your patch here with my patch for returning
> > > > errors from rockchip_pmu_set_idle_request [1].
> > >
> > > I will have a look.
> > >
> > > > > Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > > > Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
> > > > > Tested-by: Adrian Larumbe <adrian.larumbe@xxxxxxxxxxxxx> # On Rock 5B
> > > > > Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> > > > > ---
> > > > >  drivers/pmdomain/rockchip/pm-domains.c | 34 +++++++++++++++++---------
> > > > >  1 file changed, 22 insertions(+), 12 deletions(-)
> > > > >
> > > > > diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
> > > > > index a161ee13c633..8f440f2883db 100644
> > > > > --- a/drivers/pmdomain/rockchip/pm-domains.c
> > > > > +++ b/drivers/pmdomain/rockchip/pm-domains.c
> > > > > @@ -533,16 +533,17 @@ static int rockchip_pmu_domain_mem_reset(struct rockchip_pm_domain *pd)
> > > > >         return ret;
> > > > >  }
> > > > >
> > > > > -static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
> > > > > -                                            bool on)
> > > > > +static int rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
> > > > > +                                           bool on)
> > > > >  {
> > > > >         struct rockchip_pmu *pmu = pd->pmu;
> > > > >         struct generic_pm_domain *genpd = &pd->genpd;
> > > > >         u32 pd_pwr_offset = pd->info->pwr_offset;
> > > > >         bool is_on, is_mem_on = false;
> > > > > +       int ret;
> > > > >
> > > > >         if (pd->info->pwr_mask == 0)
> > > > > -               return;
> > > > > +               return 0;
> > > > >
> > > > >         if (on && pd->info->mem_status_mask)
> > > > >                 is_mem_on = rockchip_pmu_domain_is_mem_on(pd);
> > > > > @@ -557,16 +558,21 @@ static void rockchip_do_pmu_set_power_domain(struct rockchip_pm_domain *pd,
> > > > >
> > > > >         wmb();
> > > > >
> > > > > -       if (is_mem_on && rockchip_pmu_domain_mem_reset(pd))
> > > > > -               return;
> > > > > +       if (is_mem_on) {
> > > > > +               ret = rockchip_pmu_domain_mem_reset(pd);
> > > > > +               if (ret)
> > > > > +                       return ret;
> > > > > +       }
> > > > >
> > > > > -       if (readx_poll_timeout_atomic(rockchip_pmu_domain_is_on, pd, is_on,
> > > > > -                                     is_on == on, 0, 10000)) {
> > > > > -               dev_err(pmu->dev,
> > > > > -                       "failed to set domain '%s', val=%d\n",
> > > > > -                       genpd->name, is_on);
> > > > > -               return;
> > > > > +       ret = readx_poll_timeout_atomic(rockchip_pmu_domain_is_on, pd, is_on,
> > > > > +                                       is_on == on, 0, 10000);
> > > > > +       if (ret) {
> > > > > +               dev_err(pmu->dev, "failed to set domain '%s' %s, val=%d\n",
> > > > > +                       genpd->name, on ? "on" : "off", is_on);
> > > > > +               return ret;
> > > > >         }
> > > > > +
> > > > > +       return 0;
> > > > >  }
> > > > >
> > > > >  static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)
> > > > > @@ -592,7 +598,11 @@ static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)
> > > > >                         rockchip_pmu_set_idle_request(pd, true);
> > > > >                 }
> > > > >
> > > > > -               rockchip_do_pmu_set_power_domain(pd, power_on);
> > > > > +               ret = rockchip_do_pmu_set_power_domain(pd, power_on);
> > > > > +               if (ret < 0) {
> > > > > +                       clk_bulk_disable(pd->num_clks, pd->clks);
> > > > > +                       return ret;
> > > >
> > > > Looking at it, we shouldn't return directly from here because the
> > > > mutex never gets unlocked.
> > >
> > > Yes, we should do that after patch 2/7 from this series :)
> >
> > That's excellent!
> >
> > >
> > > > Instead of repeating clk_bulk_disable and return ret for each failure,
> > > > we can initialize ret = 0, have a goto: out pointing to
> > > > clk_bulk_disable, and change return 0 to return ret at the end.
> > >
> > > Right now there is only a single clk_bulk_disable() in an error
> > > case, so I did not use the typical error goto chain. I suppose
> > > it makes a lot more sense with proper error handling for the calls
> > > to rockchip_pmu_set_idle_request().
> >
> > If you'd like, I can base my v2 on this patch series with the changes
> > I'm suggesting?
> 
> I leave you guys to decide the best way forward, but please keep in
> mind that fixes/stable patches are easier managed if they are as
> simple as possible and without relying on cleanup patches. Better fix
> the problem first, then clean up the code.

I had this ordered the other way around initially and as Heiko
pointed out that makes things more complicated overall:

https://lore.kernel.org/linux-rockchip/4864529.A9s0UXYOmP@diego/

Greetings,

-- Sebastian

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