linux-kernel - Re: [PATCH v3 04/11] coresight-tpdm: Add reset node to TPDM node

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Date:   Thu, 23 Mar 2023 14:41:29 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Tao Zhang <quic_taozha@...cinc.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Konrad Dybcio <konradybcio@...il.com>,
        Mike Leach <mike.leach@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
Cc:     Jinlong Mao <quic_jinlmao@...cinc.com>,
        Leo Yan <leo.yan@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Tingwei Zhang <quic_tingweiz@...cinc.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Trilok Soni <quic_tsoni@...cinc.com>,
        Hao Zhang <quic_hazha@...cinc.com>,
        linux-arm-msm@...r.kernel.org, bjorn.andersson@...aro.org
Subject: Re: [PATCH v3 04/11] coresight-tpdm: Add reset node to TPDM node

On 23/03/2023 06:04, 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@...cinc.com>
> ---
>   drivers/hwtracing/coresight/coresight-tpdm.c | 28 ++++++++++++++++++++++++++++
>   1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 5e1e2ba..104638d 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -161,6 +161,33 @@ static void tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
>   	drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 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);
> +	/* Reset all datasets to ZERO, and init the default data*/
> +	tpdm_init_datasets(drvdata);

With the suggested rename in the previous patch, you wouldn't need
a comment here.

> +
> +	spin_unlock(&drvdata->spinlock);
> +


> +	/* Disable tpdm if enabled */
> +	if (drvdata->enable)
> +		coresight_disable(drvdata->csdev);

Couldn't this be done via disable_source ? Please don't overload
the sysfs handle.

> +
> +	return size;
> +}
> +static DEVICE_ATTR_WO(reset);

Documentation for the sysfs node please ?

Suzuki