RE: [PATCH] phy: renesas: phy-rzg3e-usb3: Fix runtime PM underflow during suspend

[Ovidiu Panait <ovidiu.panait.rb@renesas.com>]

Hi Vinod,

> 
> On 27-04-26, 19:47, Ovidiu Panait wrote:
> > On the Renesas RZ/V2H platform, if the xhcd driver is unbound and the
> > system is suspended afterwards, a PM underflow error will occur:
> >
> >  # echo 15850000.usb > /sys/bus/platform/drivers/xhci-renesas-hcd/unbind
> >  # systemctl suspend
> >  15870000.usb-phy: PM: dpm_run_callback(): genpd_resume_noirq returns -
> 13
> >  15870000.usb-phy: PM: failed to resume noirq: error -13
> >  15870000.usb-phy: Runtime PM usage count underflow!
> >
> > Since the PHY framework is managing the runtime PM of the PHY via
> > phy_power_on()/phy_power_off(), there is no need for the PHY driver to
> > manipulate the runtime PM state during suspend.
> >
> > To fix this, remove the runtime PM calls from the suspend/resume paths
> > and add a get/put pair inside rzg3e_phy_usb3_init_helper() to make sure
> > the clock is enabled during init, even when there is no consumer for
> > the PHY.
> 
> Ok
> 
> >
> > Also, change the suspend ops from NOIRQ_SYSTEM_SLEEP_PM_OPS to
> > SYSTEM_SLEEP_PM_OPS because runtime PM is disabled during the noirq
> phase
> > and pm_runtime_resume_and_get() would not actually enable the device
> clock.
> 
> This is a fix, so split this up please
> 
> >
> > Fixes: ee5f1a3f90a4 ("phy: renesas: Add Renesas RZ/G3E USB3.0 PHY
> driver")
> > Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
> > ---
> >  drivers/phy/renesas/phy-rzg3e-usb3.c | 31 ++++++++++++++++------------
> >  1 file changed, 18 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/phy/renesas/phy-rzg3e-usb3.c
> b/drivers/phy/renesas/phy-rzg3e-usb3.c
> > index 6b3453ea0004..055775e1a0f7 100644
> > --- a/drivers/phy/renesas/phy-rzg3e-usb3.c
> > +++ b/drivers/phy/renesas/phy-rzg3e-usb3.c
> > @@ -64,6 +64,7 @@
> >  #define USB3_TEST_LANECONFIG0_DEFAULT		(0xd)
> >
> >  struct rz_usb3 {
> > +	struct device *dev;
> 
> This does not belong in a fix, please split
> 

Thanks for your review, I'll split this up into multiple patches.

> >  	void __iomem *base;
> >  	struct reset_control *rstc;
> >  	bool skip_reinit;
> > @@ -130,11 +131,21 @@ static int rzg3e_phy_usb3test_phy_init(void
> __iomem *base)
> >  	return 0;
> >  }
> >
> > -static int rzg3e_phy_usb3_init_helper(void __iomem *base)
> > +static int rzg3e_phy_usb3_init_helper(struct rz_usb3 *r)
> >  {
> > -	rzg3e_phy_usb2test_phy_init(base);
> > +	int ret;
> > +
> > +	ret = pm_runtime_resume_and_get(r->dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	rzg3e_phy_usb2test_phy_init(r->base);
> >
> > -	return rzg3e_phy_usb3test_phy_init(base);
> > +	ret = rzg3e_phy_usb3test_phy_init(r->base);
> > +
> > +	pm_runtime_put_sync(r->dev);
> > +
> > +	return ret;
> >  }
> >
> >  static int rzg3e_phy_usb3_init(struct phy *p)
> > @@ -143,7 +154,7 @@ static int rzg3e_phy_usb3_init(struct phy *p)
> >  	int ret = 0;
> >
> >  	if (!r->skip_reinit)
> > -		ret = rzg3e_phy_usb3_init_helper(r->base);
> > +		ret = rzg3e_phy_usb3_init_helper(r);
> >
> >  	return ret;
> >  }
> > @@ -187,6 +198,7 @@ static int rzg3e_phy_usb3_probe(struct
> platform_device *pdev)
> >
> >  	platform_set_drvdata(pdev, r);
> >  	phy_set_drvdata(phy, r);
> > +	r->dev = dev;
> >
> >  	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> >  	if (IS_ERR(provider))
> > @@ -199,7 +211,6 @@ static int rzg3e_phy_usb3_suspend(struct device
> *dev)
> >  {
> >  	struct rz_usb3 *r = dev_get_drvdata(dev);
> >
> > -	pm_runtime_put(dev);
> >  	reset_control_assert(r->rstc);
> >  	r->skip_reinit = false;
> >
> > @@ -215,27 +226,21 @@ static int rzg3e_phy_usb3_resume(struct device
> *dev)
> >  	if (ret)
> >  		return ret;
> >
> > -	ret = pm_runtime_resume_and_get(dev);
> > +	ret = rzg3e_phy_usb3_init_helper(r);
> >  	if (ret)
> >  		goto reset_assert;
> >
> > -	ret = rzg3e_phy_usb3_init_helper(r->base);
> > -	if (ret)
> > -		goto pm_put;
> > -
> >  	r->skip_reinit = true;
> 
> https://sashiko.dev/#/patchset/20260427194741.161533-1-
> ovidiu.panait.rb%40renesas.com
> 

I think this is not applicable for our platforms, as the power domain only
gates the clock during runtime suspend, so the register state is not lost
across runtime suspend/resume.

The power domain (drivers/clk/renesas/rzv2h-cpg.c) is marked as
GENPD_FLAG_ALWAYS_ON.

Thanks,
Ovidiu

> 
> --
> ~Vinod

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