| Message ID | 1662626705-13097-5-git-send-email-quic_taozha@quicinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add support to configure TPDM DSB subunit | expand |
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, > };
Hi Suzuki, 在 10/24/2022 6:10 PM, Suzuki K Poulose 写道: > 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. For example, we usually reset the configuration through the "reset" node before using a TPDM, so as to avoid the previous configuration affecting the current use. And in some scenarios, it may be necessary to reset the TPDM configuration to complete the verification of certain function. >> >> 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 > I will update this in the next patch series. >> +{ >> + 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". > Make sense, I will update this in the next patch series. > >> + 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 ? > We usually reset the configuration through the "reset" node at the beginning of using a TPDM. DSB related elements need to be initialized before configuring them. The TPDM is usually to be used by the following sequence. Reset(initialization) -> Configure -> Enable to use >> + >> + 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 ? > In some scenarios, it may be necessary to reset the TPDM configuration in the process of verification and re-configure the TPDM. If this is the case, we need to disable the TPDM first, and re-configure before enabling it again. > > 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, >> }; > Best Regards Tao
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) +{ + int ret = 0; + unsigned long val; + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent); + + ret = kstrtoul(buf, 10, &val); + 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); + + spin_unlock(&drvdata->spinlock); + + /* Disable tpdm if enabled */ + if (drvdata->enable) + coresight_disable(drvdata->csdev); + + 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, };
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. Signed-off-by: Tao Zhang <quic_taozha@quicinc.com> --- drivers/hwtracing/coresight/coresight-tpdm.c | 32 ++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)