[PATCH v12 7/7] qcom-tgu: Add reset node to initialize

[Jie Gan]

On 3/17/2026 11:26 AM, 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 at oss.qualcomm.com>
> ---
>   .../ABI/testing/sysfs-bus-amba-devices-tgu    |  7 ++
>   drivers/hwtracing/qcom/tgu.c                  | 77 +++++++++++++++++++
>   2 files changed, 84 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> index 5370882333bc..1dcb8fb71cd9 100644
> --- a/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> +++ b/Documentation/ABI/testing/sysfs-bus-amba-devices-tgu
> @@ -42,3 +42,10 @@ KernelVersion	7.1
>   Contact:	Jinlong Mao <jinlong.mao at oss.qualcomm.com>, Songwei Chai <songwei.chai at oss.qualcomm.com>
>   Description:
>   		(RW) Set/Get the counter value with specific step for TGU.
> +
> +What:		/sys/bus/amba/devices/<tgu-name>/reset_tgu
> +Date:		March 2026
> +KernelVersion	7.1
> +Contact:	Jinlong Mao <jinlong.mao at oss.qualcomm.com>, Songwei Chai <songwei.chai at oss.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 4539415571f6..e28e6d27cf56 100644
> --- a/drivers/hwtracing/qcom/tgu.c
> +++ b/drivers/hwtracing/qcom/tgu.c
> @@ -410,8 +410,85 @@ 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)
> +{
> +	struct tgu_drvdata *drvdata = dev_get_drvdata(dev);
> +	struct value_table *vt = drvdata->value_table;
> +	u32 *cond_decode = drvdata->value_table->condition_decode;
> +	bool need_pm_put = false;
> +	unsigned long value;
> +	int i, j, ret;
> +
> +	if (kstrtoul(buf, 0, &value) || value != 1)
> +		return -EINVAL;
> +
> +	spin_lock(&drvdata->lock);
> +	if (!drvdata->enabled) {
> +		spin_unlock(&drvdata->lock);
> +		ret = pm_runtime_resume_and_get(drvdata->dev);
> +		if (ret)
> +			return ret;
> +		need_pm_put = true;
> +		spin_lock(&drvdata->lock);
> +	}
> +
> +	tgu_do_disable(drvdata);

need_pm_put flag is not set when reset a enabled device. I think we also 
need do pm_runtime_put after we did tgu_do_disable for an enabled device 
because we have pm_runtime_resume_and_get while enabling it.

Thanks,
Jie

> +
> +	if (vt->priority) {
> +		size_t size = MAX_PRIORITY * drvdata->num_step *
> +				drvdata->num_reg * sizeof(unsigned int);
> +		memset(vt->priority, 0, size);
> +	}
> +
> +	if (vt->condition_decode) {
> +		size_t size = drvdata->num_condition_decode *
> +			      drvdata->num_step * sizeof(unsigned int);
> +		memset(vt->condition_decode, 0, size);
> +	}
> +
> +	/* Initialize all condition registers to NOT(value=0x1000000) */
> +	for (i = 0; i < drvdata->num_step; i++) {
> +		for (j = 0; j < drvdata->num_condition_decode; j++) {
> +			cond_decode[calculate_array_location(drvdata, i,
> +			TGU_CONDITION_DECODE, j)] = 0x1000000;
> +		}
> +	}
> +
> +	if (vt->condition_select) {
> +		size_t size = drvdata->num_condition_select *
> +			      drvdata->num_step * sizeof(unsigned int);
> +		memset(vt->condition_select, 0, size);
> +	}
> +
> +	if (vt->timer) {
> +		size_t size = (drvdata->num_step) * (drvdata->num_timer) *
> +				sizeof(unsigned int);
> +		memset(vt->timer, 0, size);
> +	}
> +
> +	if (vt->counter) {
> +		size_t size = (drvdata->num_step) * (drvdata->num_counter) *
> +			      sizeof(unsigned int);
> +		memset(vt->counter, 0, size);
> +	}
> +
> +	spin_unlock(&drvdata->lock);
> +
> +	dev_dbg(dev, "Qualcomm-TGU reset complete\n");
> +
> +	if (need_pm_put)
> +		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,
>   };
>