* [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state
@ 2021-06-25 22:54 Bjorn Andersson
2021-06-28 5:42 ` Vinod Koul
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Bjorn Andersson @ 2021-06-25 22:54 UTC (permalink / raw)
To: Andy Gross, Bjorn Andersson, Michael Turquette, Stephen Boyd,
Vinod Koul, dmitry.baryshkov
Cc: linux-arm-msm, linux-clk, linux-kernel, stable
As GDSCs are registered and found to be already enabled
gdsc_toggle_logic() will be invoked for votable GDSCs and ensure that
the vote is matching the hardware state. Part of this the related
regulator will be enabled.
But for non-votable GDSCs the regulator and GDSC status will be out of
sync and as the GDSC is later disabled regulator_disable() will face an
unbalanced enable-count, or something might turn off the supply under
the feet of the GDSC.
So ensure that the regulator is enabled even for non-votable GDSCs.
Cc: stable@vger.kernel.org
Fixes: 37416e554961 ("clk: qcom: gdsc: Handle GDSC regulator supplies")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
drivers/clk/qcom/gdsc.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 51ed640e527b..f7e7759cdb90 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -359,10 +359,17 @@ static int gdsc_init(struct gdsc *sc)
/*
* Votable GDSCs can be ON due to Vote from other masters.
- * If a Votable GDSC is ON, make sure we have a Vote.
+ * If a Votable GDSC is ON, make sure we have a Vote. If
+ * non-votable, ensure that the supply is kept enabled (as
+ * is done by gdsc_enable).
*/
- if ((sc->flags & VOTABLE) && on)
+ if ((sc->flags & VOTABLE) && on) {
gdsc_enable(&sc->pd);
+ } else if (on) {
+ ret = regulator_enable(sc->rsupply);
+ if (ret < 0)
+ return ret;
+ }
/*
* Make sure the retain bit is set if the GDSC is already on, otherwise
--
2.29.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state
2021-06-25 22:54 [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state Bjorn Andersson
@ 2021-06-28 5:42 ` Vinod Koul
2021-06-29 6:34 ` Stephen Boyd
2021-06-29 21:05 ` Bjorn Andersson
2 siblings, 0 replies; 5+ messages in thread
From: Vinod Koul @ 2021-06-28 5:42 UTC (permalink / raw)
To: Bjorn Andersson
Cc: Andy Gross, Michael Turquette, Stephen Boyd, dmitry.baryshkov,
linux-arm-msm, linux-clk, linux-kernel, stable
On 25-06-21, 15:54, Bjorn Andersson wrote:
> As GDSCs are registered and found to be already enabled
> gdsc_toggle_logic() will be invoked for votable GDSCs and ensure that
> the vote is matching the hardware state. Part of this the related
> regulator will be enabled.
>
> But for non-votable GDSCs the regulator and GDSC status will be out of
> sync and as the GDSC is later disabled regulator_disable() will face an
> unbalanced enable-count, or something might turn off the supply under
> the feet of the GDSC.
>
> So ensure that the regulator is enabled even for non-votable GDSCs.
Reviewed-by: Vinod Koul <vkoul@kernel.org>
--
~Vinod
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state
2021-06-25 22:54 [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state Bjorn Andersson
2021-06-28 5:42 ` Vinod Koul
@ 2021-06-29 6:34 ` Stephen Boyd
2021-06-29 21:13 ` Bjorn Andersson
2021-06-29 21:05 ` Bjorn Andersson
2 siblings, 1 reply; 5+ messages in thread
From: Stephen Boyd @ 2021-06-29 6:34 UTC (permalink / raw)
To: Andy Gross, Bjorn Andersson, Michael Turquette, Vinod Koul,
dmitry.baryshkov
Cc: linux-arm-msm, linux-clk, linux-kernel, stable
Quoting Bjorn Andersson (2021-06-25 15:54:14)
> As GDSCs are registered and found to be already enabled
> gdsc_toggle_logic() will be invoked for votable GDSCs and ensure that
> the vote is matching the hardware state. Part of this the related
> regulator will be enabled.
>
> But for non-votable GDSCs the regulator and GDSC status will be out of
> sync and as the GDSC is later disabled regulator_disable() will face an
> unbalanced enable-count, or something might turn off the supply under
> the feet of the GDSC.
>
> So ensure that the regulator is enabled even for non-votable GDSCs.
>
> Cc: stable@vger.kernel.org
> Fixes: 37416e554961 ("clk: qcom: gdsc: Handle GDSC regulator supplies")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> drivers/clk/qcom/gdsc.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> index 51ed640e527b..f7e7759cdb90 100644
> --- a/drivers/clk/qcom/gdsc.c
> +++ b/drivers/clk/qcom/gdsc.c
> @@ -359,10 +359,17 @@ static int gdsc_init(struct gdsc *sc)
>
> /*
> * Votable GDSCs can be ON due to Vote from other masters.
> - * If a Votable GDSC is ON, make sure we have a Vote.
> + * If a Votable GDSC is ON, make sure we have a Vote. If
> + * non-votable, ensure that the supply is kept enabled (as
> + * is done by gdsc_enable).
> */
> - if ((sc->flags & VOTABLE) && on)
> + if ((sc->flags & VOTABLE) && on) {
> gdsc_enable(&sc->pd);
> + } else if (on) {
> + ret = regulator_enable(sc->rsupply);
> + if (ret < 0)
> + return ret;
Looking at this makes me think we've messed something up with
gdsc_enable() being called or cherry-picking the regulator enable (and
other stuff in this gdsc_init()) out of the enable path. Maybe we should
have a followup patch that replaces the gdsc_enable() with
gdsc_toggle_logic(sc, GDSC_ON) so that we know it isn't doing anything
else during init like asserting a reset when presumably all we want to
do is toggle the enable bit to assert our vote.
And I notice that we already call gdsc_toggle_logic() in gdsc_init(), so
then we'll have a double regulator_enable() in the case of PWRSTS_ON?
And then if the flag is ALWAYS_ON we'll call regulator_enable() yet
again, but luckily only if it isn't on initially, phew! This code is
quite twisted.
It would be super nice to make it more like
if (on) {
/* It was on in hardware, sync kernel state */
regulator_enable();
if (votable)
write bit, why do any wait?
if (retain ff)
write bit
} else if (always_on) {
/* Force on */
gdsc_enable();
on = true;
}
if (on || ...)
> + }
>
> /*
> * Make sure the retain bit is set if the GDSC is already on, otherwise
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state
2021-06-25 22:54 [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state Bjorn Andersson
2021-06-28 5:42 ` Vinod Koul
2021-06-29 6:34 ` Stephen Boyd
@ 2021-06-29 21:05 ` Bjorn Andersson
2 siblings, 0 replies; 5+ messages in thread
From: Bjorn Andersson @ 2021-06-29 21:05 UTC (permalink / raw)
To: Andy Gross, Michael Turquette, Stephen Boyd, Vinod Koul,
dmitry.baryshkov
Cc: linux-arm-msm, linux-clk, linux-kernel, stable
On Fri 25 Jun 17:54 CDT 2021, Bjorn Andersson wrote:
> As GDSCs are registered and found to be already enabled
> gdsc_toggle_logic() will be invoked for votable GDSCs and ensure that
> the vote is matching the hardware state. Part of this the related
> regulator will be enabled.
>
> But for non-votable GDSCs the regulator and GDSC status will be out of
> sync and as the GDSC is later disabled regulator_disable() will face an
> unbalanced enable-count, or something might turn off the supply under
> the feet of the GDSC.
>
> So ensure that the regulator is enabled even for non-votable GDSCs.
>
> Cc: stable@vger.kernel.org
> Fixes: 37416e554961 ("clk: qcom: gdsc: Handle GDSC regulator supplies")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> drivers/clk/qcom/gdsc.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> index 51ed640e527b..f7e7759cdb90 100644
> --- a/drivers/clk/qcom/gdsc.c
> +++ b/drivers/clk/qcom/gdsc.c
> @@ -359,10 +359,17 @@ static int gdsc_init(struct gdsc *sc)
>
> /*
> * Votable GDSCs can be ON due to Vote from other masters.
> - * If a Votable GDSC is ON, make sure we have a Vote.
> + * If a Votable GDSC is ON, make sure we have a Vote. If
> + * non-votable, ensure that the supply is kept enabled (as
> + * is done by gdsc_enable).
> */
> - if ((sc->flags & VOTABLE) && on)
> + if ((sc->flags & VOTABLE) && on) {
> gdsc_enable(&sc->pd);
> + } else if (on) {
I somehow lost the check for sc->rsupply != NULL while trying to make
this readable. In other words, this is broken.
Regards,
Bjorn
> + ret = regulator_enable(sc->rsupply);
> + if (ret < 0)
> + return ret;
> + }
>
> /*
> * Make sure the retain bit is set if the GDSC is already on, otherwise
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state
2021-06-29 6:34 ` Stephen Boyd
@ 2021-06-29 21:13 ` Bjorn Andersson
0 siblings, 0 replies; 5+ messages in thread
From: Bjorn Andersson @ 2021-06-29 21:13 UTC (permalink / raw)
To: Stephen Boyd
Cc: Andy Gross, Michael Turquette, Vinod Koul, dmitry.baryshkov,
linux-arm-msm, linux-clk, linux-kernel, stable
On Tue 29 Jun 01:34 CDT 2021, Stephen Boyd wrote:
> Quoting Bjorn Andersson (2021-06-25 15:54:14)
> > As GDSCs are registered and found to be already enabled
> > gdsc_toggle_logic() will be invoked for votable GDSCs and ensure that
> > the vote is matching the hardware state. Part of this the related
> > regulator will be enabled.
> >
> > But for non-votable GDSCs the regulator and GDSC status will be out of
> > sync and as the GDSC is later disabled regulator_disable() will face an
> > unbalanced enable-count, or something might turn off the supply under
> > the feet of the GDSC.
> >
> > So ensure that the regulator is enabled even for non-votable GDSCs.
> >
> > Cc: stable@vger.kernel.org
> > Fixes: 37416e554961 ("clk: qcom: gdsc: Handle GDSC regulator supplies")
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> > drivers/clk/qcom/gdsc.c | 11 +++++++++--
> > 1 file changed, 9 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> > index 51ed640e527b..f7e7759cdb90 100644
> > --- a/drivers/clk/qcom/gdsc.c
> > +++ b/drivers/clk/qcom/gdsc.c
> > @@ -359,10 +359,17 @@ static int gdsc_init(struct gdsc *sc)
> >
> > /*
> > * Votable GDSCs can be ON due to Vote from other masters.
> > - * If a Votable GDSC is ON, make sure we have a Vote.
> > + * If a Votable GDSC is ON, make sure we have a Vote. If
> > + * non-votable, ensure that the supply is kept enabled (as
> > + * is done by gdsc_enable).
> > */
> > - if ((sc->flags & VOTABLE) && on)
> > + if ((sc->flags & VOTABLE) && on) {
> > gdsc_enable(&sc->pd);
> > + } else if (on) {
> > + ret = regulator_enable(sc->rsupply);
> > + if (ret < 0)
> > + return ret;
>
> Looking at this makes me think we've messed something up with
> gdsc_enable() being called or cherry-picking the regulator enable (and
> other stuff in this gdsc_init()) out of the enable path. Maybe we should
> have a followup patch that replaces the gdsc_enable() with
> gdsc_toggle_logic(sc, GDSC_ON) so that we know it isn't doing anything
> else during init like asserting a reset when presumably all we want to
> do is toggle the enable bit to assert our vote.
>
> And I notice that we already call gdsc_toggle_logic() in gdsc_init(), so
> then we'll have a double regulator_enable() in the case of PWRSTS_ON?
> And then if the flag is ALWAYS_ON we'll call regulator_enable() yet
> again, but luckily only if it isn't on initially, phew! This code is
> quite twisted.
>
> It would be super nice to make it more like
>
> if (on) {
> /* It was on in hardware, sync kernel state */
> regulator_enable();
>
> if (votable)
> write bit, why do any wait?
>
> if (retain ff)
> write bit
> } else if (always_on) {
> /* Force on */
> gdsc_enable();
> on = true;
> }
>
> if (on || ...)
>
This does look cleaner, I will dig through the logic here once more
before figuring out what to do for v2.
Thanks,
Bjorn
> > + }
> >
> > /*
> > * Make sure the retain bit is set if the GDSC is already on, otherwise
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-06-29 21:14 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2021-06-25 22:54 [PATCH] clk: qcom: gdsc: Ensure regulator init state matches GDSC state Bjorn Andersson
2021-06-28 5:42 ` Vinod Koul
2021-06-29 6:34 ` Stephen Boyd
2021-06-29 21:13 ` Bjorn Andersson
2021-06-29 21:05 ` Bjorn Andersson
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