linux-kernel - Re: [PATCH 2/3] drivers: thermal: tsens: Add watchdog support

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Message-ID: <CAHLCerN1n7c76MicKWCWE8aSpxrwrMEuN1mAtPwXykFWi2vEuQ@mail.gmail.com>
Date:   Fri, 29 Nov 2019 00:46:26 +0530
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Eduardo Valentin <edubezval@...il.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, sivaa@...eaurora.org,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 2/3] drivers: thermal: tsens: Add watchdog support

On Fri, Nov 15, 2019 at 4:08 AM Stephen Boyd <swboyd@...omium.org> wrote:
>
> Quoting Amit Kucheria (2019-11-11 11:21:28)
> > TSENS IP v2.3 onwards adds support for a watchdog to detect if the TSENS
> > HW FSM is frozen. Add support to detect and restart the FSM in the
>
> Maybe 'frozen' is an ambiguous term? Maybe 'stuck' or 'has stopped
> making progress'?

Alright, let's keep Disney out of this. Will use 'stuck'.

> > driver. The watchdog is configured by the bootloader, we just enable the
> > feature in the kernel.
>
> Does it work to enable it if we don't configure it in the bootloader?

TBH, I don't know. Getting modified firmware to test this will be a
bit of a challenge.

> >
> > Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
> > ---
> >  drivers/thermal/qcom/tsens-common.c | 41 +++++++++++++++++++++++++++++
> >  drivers/thermal/qcom/tsens-v2.c     | 10 +++++++
> >  drivers/thermal/qcom/tsens.h        | 12 +++++++++
> >  3 files changed, 63 insertions(+)
> >
> > diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
> > index 2989cb952cdb..9432518502a7 100644
> > --- a/drivers/thermal/qcom/tsens-common.c
> > +++ b/drivers/thermal/qcom/tsens-common.c
> > @@ -794,6 +820,21 @@ int __init init_common(struct tsens_priv *priv)
> >                 }
> >         }
> >
> > +       if (tsens_version(priv) > VER_1_X &&  ver_minor > 2) {
> > +               /* Watchdog is present only on v2.3+ */
> > +               for (i = 0, j = WDOG_BARK_STATUS; j <= CC_MON_MASK; i++, j++) {
>
> The variable 'i' is not actually used in this loop. What's going on?

Sorry, left over from a botched copy-paste job from the loop above
this. Will fix.

>
> > +                       priv->rf[j] = devm_regmap_field_alloc(dev, priv->tm_map,
> > +                                                             priv->fields[j]);
> > +                       if (IS_ERR(priv->rf[j])) {
> > +                               ret = PTR_ERR(priv->rf[j]);
> > +                               goto err_put_device;
> > +                       }
> > +               }
> > +               /* Enable WDOG and disable cycle completion monitoring */
> > +               regmap_field_write(priv->rf[WDOG_BARK_MASK], 0);
> > +               regmap_field_write(priv->rf[CC_MON_MASK], 1);
> > +       }