FROMLIST: coresight-tgu: add reset node to initialize

Add reset node to initialize the value of
priority/condition_decode/condition_select/timer/counter nodes

Link: https://lore.kernel.org/all/20250423-tgu_patch-v5-7-3b52c105cc63@quicinc.com/
Signed-off-by: Songwei Chai <quic_songchai@quicinc.com>

Author: Songwei Chai

Documentation/ABI/testing/sysfs-bus-coresight-devices-tgu

@@ -42,3 +42,10 @@ KernelVersion   6.15
 Contact:        Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Sam Chai (QUIC) <quic_songchai@quicinc.com>
 Description:
                 (RW) Set/Get the counter value with specific step for TGU.
+
+What:           /sys/bus/coresight/devices/<tgu-name>/reset_tgu
+Date:           February 2025
+KernelVersion   6.15
+Contact:        Jinlong Mao (QUIC) <quic_jinlmao@quicinc.com>, Sam Chai (QUIC) <quic_songchai@quicinc.com>
+Description:
+                (Write) Write 1 to reset the dataset for TGU.

drivers/hwtracing/coresight/coresight-tgu.c

@@ -477,6 +477,80 @@ 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);
+
+	tgu_writel(drvdata, 0, 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,
@@ -488,6 +562,7 @@ static const struct coresight_ops tgu_ops = {
 
 static struct attribute *tgu_common_attrs[] = {
 	&dev_attr_enable_tgu.attr,
+	&dev_attr_reset_tgu.attr,
 	NULL,
 };