Re: [PATCH V1] mmc: sdhci-msm: Add system suspend/resume callbacks

[sbhanu]

On 2020-01-22 22:27, Stephen Boyd wrote:
> Quoting Shaik Sajida Bhanu (2020-01-21 06:30:22)
> > Add system suspend/resume callbacks to sdhci-msm platform driver.
>
> Yes, but why? There are already suspend/resume callbacks so this is
> replacing them too.

Sure. Will update the commit text.

The present suspend/resume callbacks are only disabling the clocks.

Since eMMC/SDcard would be powered off during system suspend, we can do 
little more like

resetting controller, disabling interrupts. So updating the existing 
callbacks.

> > Signed-off-by: Shaik Sajida Bhanu <sbhanu@xxxxxxxxxxxxxx>
> > ---
> >  drivers/mmc/host/sdhci-msm.c | 47 
> > ++++++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 45 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-msm.c 
> > b/drivers/mmc/host/sdhci-msm.c
> > index 71f29ba..4984857 100644
> > --- a/drivers/mmc/host/sdhci-msm.c
> > +++ b/drivers/mmc/host/sdhci-msm.c
> > @@ -2028,9 +2028,52 @@ static __maybe_unused int 
> > sdhci_msm_runtime_resume(struct device *dev)
> >         return 0;
> >  }
> >
> > +static int sdhci_msm_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);
> > +       int ret = 0;
> > +
> > +       if (host->mmc->caps2 & MMC_CAP2_CQE) {
>
> It would be nice if this if check was rolled into cqhci_suspend so that
> all the callers wouldn't have to check it.
>
> > +               ret = cqhci_suspend(host->mmc);
> > +               if (ret)
> > +                       return ret;
> > +       }
> > +
> > +       disable_irq(msm_host->pwr_irq);
>
> Why is the irq disabled? Please add a comment.

Will add a comment.

During system suspend all SDHC interrupts can be disabled since device 
would be

in power down state.

> > +       ret = sdhci_suspend_host(host);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return sdhci_msm_runtime_suspend(dev);
>
> pm_runtime_force_suspend() does different things than just call the
> runtime suspend function for the driver. For example, it disables
> runtime PM on the device. Can you explain in the commit text how this 
> is
> a correct conversion?

Will invoke pm_runtime_force_suspend() here instead of 
sdhci_msm_runtime_suspend()

> > +}
> > +
> > +static int sdhci_msm_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);
> > +       int ret = 0;
> > +
> > +       ret = sdhci_msm_runtime_resume(dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = sdhci_resume_host(host);
> > +       if (ret < 0)
> > +               return ret;
> > +       enable_irq(msm_host->pwr_irq);
>
> Same question here about irq. Deserves a comment.
>
> > +
> > +       if (host->mmc->caps2 & MMC_CAP2_CQE)
> > +               ret = cqhci_resume(host->mmc);
> > +
> > +       return ret;
> > +}
> > +
> >  static const struct dev_pm_ops sdhci_msm_pm_ops = {
> > -       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > -                               pm_runtime_force_resume)
> > +       SET_SYSTEM_SLEEP_PM_OPS(sdhci_msm_suspend,
> > +                               sdhci_msm_resume)
> >         SET_RUNTIME_PM_OPS(sdhci_msm_runtime_suspend,
> >                            sdhci_msm_runtime_resume,
> >                            NULL)