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SubjectRe: [PATCH v4 04/11] coresight-tpdm: Add reset node to TPDM node
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On 27/04/2023 10:00, 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.
>
> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
> ---
> .../ABI/testing/sysfs-bus-coresight-devices-tpdm | 10 ++++++++
> drivers/hwtracing/coresight/coresight-tpdm.c | 27 ++++++++++++++++++++++
> 2 files changed, 37 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> index 4a58e64..686bdde 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
> @@ -11,3 +11,13 @@ Description:
> Accepts only one of the 2 values - 1 or 2.
> 1 : Generate 64 bits data
> 2 : Generate 32 bits data
> +
> +What: /sys/bus/coresight/devices/<tpdm-name>/reset
> +Date: March 2023
> +KernelVersion 6.3
> +Contact: Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Tao Zhang (QUIC) <quic_taozha@quicinc.com>
> +Description:
> + (Write) Reset the dataset of the tpdm, and disable the tpdm.
> +
> + Accepts only one value - 1.
> + 1 : Reset the dataset of the tpdm
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 6f8a8ab..2e64cfd 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -164,6 +164,32 @@ static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
> return 0;
> }
>
> +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 || val != 1)
> + return -EINVAL;
> +
> + spin_lock(&drvdata->spinlock);
> + tpdm_reset_datasets(drvdata);
> +
> + spin_unlock(&drvdata->spinlock);
> +
> + /* Disable tpdm if enabled */
> + if (drvdata->enable)
> + coresight_disable_source(drvdata->csdev, NULL);

I am not really keen on doing this behind the back. What about the path
of components ? We could simply reject the request when the TPDA is
enabled and let the user alway follow :
1) Disable the TPDM manually via sysfs
2) Reset the TPDM.

So, please remove the disable step here.

Suzuki


> +
> + return size;
> +}
> +static DEVICE_ATTR_WO(reset);
> +
> /*
> * value 1: 64 bits test data
> * value 2: 32 bits test data
> @@ -204,6 +230,7 @@ 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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