Re: [PATCH v2 4/9] coresight-tpdm: Add reset node to TPDM node

[Tao Zhang]

在 2/28/2023 7:22 PM, Suzuki K Poulose 写道:
> On 19/01/2023 07:41, Tao Zhang wrote:
> > TPDM device need a node to reset the configurations and status of
> > it. So as to avoid the previous configurations affecting the
> > current use, the configurations need to be reset first. And in
> > some scenarios, it may be necessary to reset the TPDM
> > configurations to complete the verification of certain function.
> > This change provides a node to reset the configurations and
> > disable the TPDM if it has been enabled.
> >
> > Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
> > Signed-off-by: Tao Zhang <taozha@xxxxxxxxxxxxxxxx>
> > ---
> >   drivers/hwtracing/coresight/coresight-tpdm.c | 32 
> > ++++++++++++++++++++++++++++
> >   1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
> > b/drivers/hwtracing/coresight/coresight-tpdm.c
> > index 6befc87..c29d667d 100644
> > --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> > +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> > @@ -161,6 +161,37 @@ static void tpdm_init_default_data(struct 
> > tpdm_drvdata *drvdata)
> >       }
> >   }
> >   +static ssize_t reset_store(struct device *dev,
> > +                      struct device_attribute *attr,
> > +                      const char *buf,
> > +                      size_t size)
> > +{
> > +    int ret = 0;
> > +    unsigned long val;
> > +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > +
> > +    ret = kstrtoul(buf, 0, &val);
> > +    if (ret || (val != 1))
> > +        return -EINVAL;
> > +
> > +    spin_lock(&drvdata->spinlock);
> > +    /* Reset all datasets to ZERO */
> > +    if (drvdata->dsb != NULL)
> > +        memset(drvdata->dsb, 0, sizeof(struct dsb_dataset));
> > +
> > +    /* Init the default data */
>
> Code is self explanatory, don't need a comment here.
OK, got it.
> > +    tpdm_init_default_data(drvdata);
>
> Could this be helper be renamed to
>
>     tpdm_reset_dsb_data() ?
>
> Because, that is what it does now.

Sure, I will change its name as "tpdm_reset_data()" since DSB is only 
one of the data type which TPDM supports.

> > +
> > +    spin_unlock(&drvdata->spinlock);
> > +
> > +    /* Disable tpdm if enabled */
> > +    if (drvdata->enable)
> > +        coresight_disable(drvdata->csdev);
>
> Woh, where did that come from ? Don't you have a disable handle ?

The function "coresight_disable" is defined in the file "coresight-core.c".

This is a generic disablement handle.

> > +
> > +    return size;
> > +}
> > +static DEVICE_ATTR_WO(reset);
> > +
>
> This looks a bit pointless to me, given we have separate controls for 
> all that is being achieved above.

I will move the function of resetting all datasets to zero to 
"tpdm_disable".

Thanks for your advice.

> Suzuki
>
> >   /*
> >    * value 1: 64 bits test data
> >    * value 2: 32 bits test data
> > @@ -201,6 +232,7 @@ static ssize_t integration_test_store(struct 
> > device *dev,
> >   static DEVICE_ATTR_WO(integration_test);
> >     static struct attribute *tpdm_attrs[] = {
> > +    &dev_attr_reset.attr,
> >       &dev_attr_integration_test.attr,
> >       NULL,
> >   };
Best,

Tao