linux-kernel - Re: [PATCH v9 7/7] qcom-tgu: Add reset node to initialize

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Message-ID: <aa3ee735-8ef1-4f44-9528-e93ebec2a215@oss.qualcomm.com>
Date: Thu, 25 Dec 2025 13:56:37 +0800
From: Jie Gan <jie.gan@....qualcomm.com>
To: Songwei Chai <songwei.chai@....qualcomm.com>, andersson@...nel.org,
        alexander.shishkin@...ux.intel.com, mike.leach@...aro.org,
        suzuki.poulose@....com, james.clark@....com, krzk+dt@...nel.org,
        conor+dt@...nel.org
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, coresight@...ts.linaro.org,
        devicetree@...r.kernel.org, gregkh@...uxfoundation.org
Subject: Re: [PATCH v9 7/7] qcom-tgu: Add reset node to initialize



On 12/19/2025 2:59 PM, Songwei Chai wrote:
> Add reset node to initialize the value of
> priority/condition_decode/condition_select/timer/counter nodes.
> 
> Signed-off-by: Songwei Chai <songwei.chai@....qualcomm.com>
> ---
>   .../ABI/testing/sysfs-bus-amba-devices-tgu    |  7 ++
>   drivers/hwtracing/qcom/tgu.c                  | 74 +++++++++++++++++++
>   2 files changed, 81 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> index 010eade0a1c5..0733b3e07b45 100644
> --- a/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> +++ b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> @@ -42,3 +42,10 @@ KernelVersion	6.19
>   Contact:	Jinlong Mao <jinlong.mao@....qualcomm.com>, Songwei Chai <songwei.chai@....qualcomm.com>
>   Description:
>   		(RW) Set/Get the counter value with specific step for TGU.
> +
> +What:		/sys/bus/amba/devices/<tgu-name>/reset_tgu
> +Date:		December 2025
> +KernelVersion	6.19
> +Contact:	Jinlong Mao <jinlong.mao@....qualcomm.com>, Songwei Chai <songwei.chai@....qualcomm.com>
> +Description:
> +		(Write) Write 1 to reset the dataset for TGU.
> diff --git a/drivers/hwtracing/qcom/tgu.c b/drivers/hwtracing/qcom/tgu.c
> index d4210869556e..5a8c6af9b719 100644
> --- a/drivers/hwtracing/qcom/tgu.c
> +++ b/drivers/hwtracing/qcom/tgu.c
> @@ -425,8 +425,82 @@ static ssize_t enable_tgu_store(struct device *dev,
>   }
>   static DEVICE_ATTR_RW(enable_tgu);
>   
> +/* reset_tgu_store - Reset Trace and Gating Unit (TGU) configuration. */
> +static ssize_t reset_tgu_store(struct device *dev,
> +			       struct device_attribute *attr, const char *buf,
> +			       size_t size)
> +{
> +	unsigned long value;
> +	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
> +	int i, j, ret;
> +
> +	if (kstrtoul(buf, 0, &value) || value == 0)
> +		return -EINVAL;
> +
> +	if (!drvdata->enable) {
> +		ret = pm_runtime_get_sync(drvdata->dev);
> +		if (ret < 0) {
> +			pm_runtime_put(drvdata->dev);
> +			return ret;
> +		}
> +	}
> +
> +	guard(spinlock)(&drvdata->lock);
> +	TGU_UNLOCK(drvdata->base);
> +
> +	writel(0, drvdata->base + TGU_CONTROL);

Better move TGU_LOCK(drvdata->base) here

Thanks,
Jie

> +
> +	if (drvdata->value_table->priority)
> +		memset(drvdata->value_table->priority, 0,
> +			    MAX_PRIORITY * drvdata->max_step *
> +				drvdata->max_reg * sizeof(unsigned int));
> +
> +	if (drvdata->value_table->condition_decode)
> +		memset(drvdata->value_table->condition_decode, 0,
> +			    drvdata->max_condition_decode * drvdata->max_step *
> +				sizeof(unsigned int));
> +
> +		/* Initialize all condition registers to NOT(value=0x1000000) */
> +	for (i = 0; i < drvdata->max_step; i++) {
> +		for (j = 0; j < drvdata->max_condition_decode; j++) {
> +			drvdata->value_table
> +			->condition_decode[calculate_array_location(
> +			drvdata, i, TGU_CONDITION_DECODE, j)] =
> +			0x1000000;
> +		}
> +	}
> +
> +	if (drvdata->value_table->condition_select)
> +		memset(drvdata->value_table->condition_select, 0,
> +				drvdata->max_condition_select * drvdata->max_step *
> +				sizeof(unsigned int));
> +
> +	if (drvdata->value_table->timer)
> +		memset(drvdata->value_table->timer, 0,
> +			    (drvdata->max_step) *
> +				(drvdata->max_timer) *
> +				sizeof(unsigned int));
> +
> +	if (drvdata->value_table->counter)
> +		memset(drvdata->value_table->counter, 0,
> +			    (drvdata->max_step) *
> +				(drvdata->max_counter) *
> +				sizeof(unsigned int));
> +
> +	dev_dbg(dev, "Coresight-TGU reset complete\n");
> +
> +	TGU_LOCK(drvdata->base);
> +
> +	drvdata->enable = false;
> +	pm_runtime_put(drvdata->dev);
> +
> +	return size;
> +}
> +static DEVICE_ATTR_WO(reset_tgu);
> +
>   static struct attribute *tgu_common_attrs[] = {
>   	&dev_attr_enable_tgu.attr,
> +	&dev_attr_reset_tgu.attr,
>   	NULL,
>   };
>