linux-kernel - Re: [PATCH] mmc: sdhci-msm: pervent access to suspended controller

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Date: Wed, 27 Mar 2024 16:17:43 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: Mantas Pucka <mantas@...vices.com>, Bjorn Andersson <andersson@...nel.org>, 
	Konrad Dybcio <konrad.dybcio@...aro.org>, Georgi Djakov <djakov@...nel.org>, 
	Pramod Gurav <pramod.gurav@...aro.org>, Ritesh Harjani <ritesh.list@...il.com>, 
	linux-mmc@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] mmc: sdhci-msm: pervent access to suspended controller

On Tue, 26 Mar 2024 at 11:25, Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 21/03/24 16:30, Mantas Pucka wrote:
> > Generic sdhci code registers LED device and uses host->runtime_suspended
> > flag to protect access to it. The sdhci-msm driver doesn't set this flag,
> > which causes a crash when LED is accessed while controller is runtime
> > suspended. Fix this by setting the flag correctly.
> >
> > Cc: stable@...r.kernel.org
> > Fixes: 67e6db113c90 ("mmc: sdhci-msm: Add pm_runtime and system PM support")
> > Signed-off-by: Mantas Pucka <mantas@...vices.com>
>
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>

Looks like this problem may exist for other sdhci drivers too. In
particular for those that enables runtime PM, don't set
SDHCI_QUIRK_NO_LED and don't use sdhci_runtime|suspend_resume_host().

Don't know if there is a better way to address this, if not on a case
by case basis. Do you have any thoughts about this?

Kind regards
Uffe

>
> > ---
> >  drivers/mmc/host/sdhci-msm.c | 16 +++++++++++++++-
> >  1 file changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > index 668e0aceeeba..e113b99a3eab 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -2694,6 +2694,11 @@ static __maybe_unused int sdhci_msm_runtime_suspend(struct device *dev)
> >       struct sdhci_host *host = dev_get_drvdata(dev);
> >       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> >       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> > +     unsigned long flags;
> > +
> > +     spin_lock_irqsave(&host->lock, flags);
> > +     host->runtime_suspended = true;
> > +     spin_unlock_irqrestore(&host->lock, flags);
> >
> >       /* Drop the performance vote */
> >       dev_pm_opp_set_rate(dev, 0);
> > @@ -2708,6 +2713,7 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
> >       struct sdhci_host *host = dev_get_drvdata(dev);
> >       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> >       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> > +     unsigned long flags;
> >       int ret;
> >
> >       ret = clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
> > @@ -2726,7 +2732,15 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
> >
> >       dev_pm_opp_set_rate(dev, msm_host->clk_rate);
> >
> > -     return sdhci_msm_ice_resume(msm_host);
> > +     ret = sdhci_msm_ice_resume(msm_host);
> > +     if (ret)
> > +             return ret;
> > +
> > +     spin_lock_irqsave(&host->lock, flags);
> > +     host->runtime_suspended = false;
> > +     spin_unlock_irqrestore(&host->lock, flags);
> > +
> > +     return ret;
> >  }
> >
> >  static const struct dev_pm_ops sdhci_msm_pm_ops = {
> >
> > ---
> > base-commit: e8f897f4afef0031fe618a8e94127a0934896aba
> > change-id: 20240321-sdhci-mmc-suspend-34f4af1d0286
> >
> > Best regards,
>