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

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Message-Id: <20251021025909.3627254-8-songwei.chai@oss.qualcomm.com>
Date: Mon, 20 Oct 2025 19:59:09 -0700
From: Songwei Chai <songwei.chai@....qualcomm.com>
To: andersson@...nel.org, alexander.shishkin@...ux.intel.com,
        kernel@....qualcomm.com, mike.leach@...aro.org, suzuki.poulose@....com
Cc: Songwei Chai <songwei.chai@....qualcomm.com>, 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
Subject: [RESEND RFC PATCH 7/7] qcom-tgu: Add reset node to initialize

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>
---
 .../testing/sysfs-bus-coresight-devices-tgu   |  7 ++
 drivers/hwtracing/qcom/tgu.c                  | 75 +++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
index a57bf9783641..c9e12b298b23 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu
@@ -42,3 +42,10 @@ KernelVersion	6.18
 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/coresight/devices/<tgu-name>/reset_tgu
+Date:		October 2025
+KernelVersion	6.18
+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 c4ae1f27d9ff..9bef9d8b4690 100644
--- a/drivers/hwtracing/qcom/tgu.c
+++ b/drivers/hwtracing/qcom/tgu.c
@@ -434,6 +434,80 @@ 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->parent);
+	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;
+		}
+	}
+
+	spin_lock(&drvdata->spinlock);
+	CS_UNLOCK(drvdata->base);
+
+	writel(0, drvdata->base + TGU_CONTROL);
+
+	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");
+
+	CS_LOCK(drvdata->base);
+
+	drvdata->enable = false;
+	spin_unlock(&drvdata->spinlock);
+	pm_runtime_put(drvdata->dev);
+
+	return size;
+}
+static DEVICE_ATTR_WO(reset_tgu);
+
 static const struct coresight_ops_helper tgu_helper_ops = {
 	.enable = tgu_enable,
 	.disable = tgu_disable,
@@ -445,6 +519,7 @@ static const struct coresight_ops tgu_ops = {
 
 static struct attribute *tgu_common_attrs[] = {
 	&dev_attr_enable_tgu.attr,
+	&dev_attr_reset_tgu.attr,
 	NULL,
 };