[PATCH] mmc: mediatek: Add system suspend/resume interface

[Nicolas Boichat]

This causes a 0-day warning (on our chromeos-5.4 backports but I don't
see why upstream would not be affected):
https://groups.google.com/g/cros-kernel-buildreports/c/MfS3SInT5jg/m/Hkzxh_U7AwAJ

Didn't look at the details of the config, but SET_SYSTEM_SLEEP_PM_OPS
is a noop if CONFIG_PM_SLEEP is not set (while SET_RUNTIME_PM_OPS is
noop-ed by CONFIG_PM).

So I guess msdc_suspend/msdc_resume should be guarded by
CONFIG_PM_SLEEP instead of CONFIG_PM.

On Wed, Nov 25, 2020 at 9:12 AM Wenbin Mei <wenbin.mei at mediatek.com> wrote:
>
> On Mon, 2020-11-23 at 17:06 +0100, Ulf Hansson wrote:
> > On Wed, 18 Nov 2020 at 07:34, Wenbin Mei <wenbin.mei at mediatek.com> wrote:
> > >
> > > Before we got these errors on MT8192 platform:
> > > [   59.153891] Restarting tasks ...
> > > [   59.154540] done.
> > > [   59.159175] PM: suspend exit
> > > [   59.218724] mtk-msdc 11f60000.mmc: phase: [map:fffffffe] [maxlen:31]
> > > [final:16]
> > > [  119.776083] mmc0: cqhci: timeout for tag 9
> > > [  119.780196] mmc0: cqhci: ============ CQHCI REGISTER DUMP ===========
> > > [  119.786709] mmc0: cqhci: Caps:      0x100020b6 | Version:  0x00000510
> > > [  119.793225] mmc0: cqhci: Config:    0x00000101 | Control:  0x00000000
> > > [  119.799706] mmc0: cqhci: Int stat:  0x00000000 | Int enab: 0x00000000
> > > [  119.806177] mmc0: cqhci: Int sig:   0x00000000 | Int Coal: 0x00000000
> > > [  119.812670] mmc0: cqhci: TDL base:  0x00000000 | TDL up32: 0x00000000
> > > [  119.819149] mmc0: cqhci: Doorbell:  0x003ffc00 | TCN:      0x00000200
> > > [  119.825656] mmc0: cqhci: Dev queue: 0x00000000 | Dev Pend: 0x00000000
> > > [  119.832155] mmc0: cqhci: Task clr:  0x00000000 | SSC1:     0x00001000
> > > [  119.838627] mmc0: cqhci: SSC2:      0x00000000 | DCMD rsp: 0x00000000
> > > [  119.845174] mmc0: cqhci: RED mask:  0xfdf9a080 | TERRI:    0x0000891c
> > > [  119.851654] mmc0: cqhci: Resp idx:  0x00000000 | Resp arg: 0x00000000
> > > [  119.865773] mmc0: cqhci: : ===========================================
> > > [  119.872358] mmc0: running CQE recovery
> > > From these logs, we found TDL base was back to the default value.
> > >
> > > After suspend, the mmc host is powered off by HW, and bring CQE register
> > > to the default value, so we add system suspend/resume interface, then bring
> > > CQE to deactivated state before suspend, it will be enabled by CQE first
> > > request after resume.
> > >
> > > Signed-off-by: Wenbin Mei <wenbin.mei at mediatek.com>
> >
> > I took the liberty of renaming msdc_sys_suspend|resume to
> > msdc_suspend|resume, as I think the "_sys" is a bit superfluous.
> >
> > Additionally, I added a fixes+stable tag, then I applied this for fixes, thanks!
> >
> > Please tell me, if there is anything you would like me to change.
> >
> > Kind regards
> > Uffe
> >
> > It is OK for me, thanks for your help.
>
> > > ---
> > >  drivers/mmc/host/mtk-sd.c | 22 ++++++++++++++++++++--
> > >  1 file changed, 20 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > > index fc5ee5df91ad..c5f9cd6fc951 100644
> > > --- a/drivers/mmc/host/mtk-sd.c
> > > +++ b/drivers/mmc/host/mtk-sd.c
> > > @@ -2758,11 +2758,29 @@ static int msdc_runtime_resume(struct device *dev)
> > >         msdc_restore_reg(host);
> > >         return 0;
> > >  }
> > > +
> > > +static int msdc_sys_suspend(struct device *dev)
> > > +{
> > > +       struct mmc_host *mmc = dev_get_drvdata(dev);
> > > +       int ret;
> > > +
> > > +       if (mmc->caps2 & MMC_CAP2_CQE) {
> > > +               ret = cqhci_suspend(mmc);
> > > +               if (ret)
> > > +                       return ret;
> > > +       }
> > > +
> > > +       return pm_runtime_force_suspend(dev);
> > > +}
> > > +
> > > +static int msdc_sys_resume(struct device *dev)
> > > +{
> > > +       return pm_runtime_force_resume(dev);
> > > +}
> > >  #endif
> > >
> > >  static const struct dev_pm_ops msdc_dev_pm_ops = {
> > > -       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> > > -                               pm_runtime_force_resume)
> > > +       SET_SYSTEM_SLEEP_PM_OPS(msdc_sys_suspend, msdc_sys_resume)
> > >         SET_RUNTIME_PM_OPS(msdc_runtime_suspend, msdc_runtime_resume, NULL)
> > >  };
> > >
> > > --
> > > 2.18.0
> > >
>