Re: [PATCH v2 2/3] coresight: cti: Add PM runtime call in enable_store

[Jinlong Mao]

On 1/10/2023 12:47 AM, Suzuki K Poulose wrote:
> On 06/01/2023 15:23, James Clark wrote:
> > From: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> >
> > In commit 6746eae4bbad ("coresight: cti: Fix hang in cti_disable_hw()")
> > PM runtime calls are removed from cti_enable_hw/cti_disable_hw. When
> > enabling CTI by writing enable sysfs node, clock for accessing CTI
> > register won't be enabled. Device will crash due to register access
> > issue. Add PM runtime call in enable_store to fix this issue.
> >
> > Fixes: 6746eae4bbad ("coresight: cti: Fix hang in cti_disable_hw()")
> > Signed-off-by: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
> > [Change to only call pm_runtime_put if a disable happened]
> > Signed-off-by: James Clark <james.clark@xxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-cti-sysfs.c | 13 +++++++++++--
> >   1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c 
> > b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > index 6d59c815ecf5..71e7a8266bb3 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > @@ -108,10 +108,19 @@ static ssize_t enable_store(struct device *dev,
> >       if (ret)
> >           return ret;
> >   -    if (val)
> > +    if (val) {
> > +        ret = pm_runtime_resume_and_get(dev->parent);
> > +        if (ret)
> > +            return ret;
> >           ret = cti_enable(drvdata->csdev);
> > -    else
> > +        if (ret)
> > +            pm_runtime_put(dev->parent);
> > +    } else {
> >           ret = cti_disable(drvdata->csdev);
> > +        if (!ret)
> > +            pm_runtime_put(dev->parent);
> > +    }
> > +
> >       if (ret)
> >           return ret;
> >       return size;
>
> Looks good to me.
>
> @Mao Jinolong,
>
> Are you able to test the patches 1 & 2 and confirm they solve your 
> issue ?

Hi Suzuki,

Tested from my side. Patch 1 & 2 can solve the issue when enable CTI by 
writing 1 to enable sysfs node.

Thanks
Jinlong Mao
> Suzuki