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@xxxxxxxxxxx>
---
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
