Messages in this thread | | | Date | Mon, 24 Oct 2022 11:10:48 +0100 | Subject | Re: [PATCH 4/9] coresight-tpdm: Add reset node to TPDM node | From | Suzuki K Poulose <> |
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On 08/09/2022 09:45, Tao Zhang wrote: > TPDM device need a node to reset the configurations and status of > it. This change provides a node to reset the configurations and > disable the TPDM if it has been enabled.
It is not clear to me *why* this is needed. Please could you elaborate on the use case of this ? See my questions below.
> > Signed-off-by: Tao Zhang <quic_taozha@quicinc.com> > --- > 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 69ea453..74cc653 100644 > --- a/drivers/hwtracing/coresight/coresight-tpdm.c > +++ b/drivers/hwtracing/coresight/coresight-tpdm.c > @@ -152,6 +152,37 @@ 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)
minor nit: Alignment
> +{ > + int ret = 0; > + unsigned long val; > + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent); > + > + ret = kstrtoul(buf, 10, &val);
So, any integer value written to the sysfs knob triggers the rest ? It may be better to restrict this to "1".
> + if (ret) > + return ret; > + > + 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 */ > + tpdm_init_default_data(drvdata);
Why is this needed ? Does the DSB device configuration change on the fly ?
> + > + spin_unlock(&drvdata->spinlock); > + > + /* Disable tpdm if enabled */ > + if (drvdata->enable) > + coresight_disable(drvdata->csdev);
Why is this needed ? Isn't this supposed to be triggered from the "path" when the trace session is complete ?
Suzuki
> + > + return size; > +} > +static DEVICE_ATTR_WO(reset); > + > /* > * value 1: 64 bits test data > * value 2: 32 bits test data > @@ -192,6 +223,7 @@ 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, > };
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