[PATCH 11/24] gtrace: Add RISC-V trace timestamp support

23 Oct 2026

Add a shared timestamp component for the RISC-V trace encoder and
funnel.
Signed-off-by: Zane Leung liangzhen@linux.spacemit.com
---
 drivers/hwtracing/gtrace/Makefile             |   3 +-
 .../hwtracing/gtrace/rvtrace-encoder-core.c   |  16 +-
 .../hwtracing/gtrace/rvtrace-encoder-sysfs.c  |  33 ++
 drivers/hwtracing/gtrace/rvtrace-encoder.h    |   8 +
 drivers/hwtracing/gtrace/rvtrace-funnel.c     |  55 +++
 drivers/hwtracing/gtrace/rvtrace-funnel.h     |   8 +
 drivers/hwtracing/gtrace/rvtrace-timestamp.c  | 336 ++++++++++++++++++
 drivers/hwtracing/gtrace/rvtrace-timestamp.h  |  44 +++
 8 files changed, 500 insertions(+), 3 deletions(-)
 create mode 100644 drivers/hwtracing/gtrace/rvtrace-timestamp.c
 create mode 100644 drivers/hwtracing/gtrace/rvtrace-timestamp.h

diff --git a/drivers/hwtracing/gtrace/Makefile b/drivers/hwtracing/gtrace/Makefile
index 9c99d917b9f4..b60d3cfe5248 100644
--- a/drivers/hwtracing/gtrace/Makefile
+++ b/drivers/hwtracing/gtrace/Makefile
@@ -4,7 +4,8 @@ obj-$(CONFIG_GTRACE) += gtrace.o
 gtrace-y := gtrace-core.o gtrace-perf.o gtrace-sysfs.o
 gtrace-$(CONFIG_OF) += gtrace-of.o
-obj-$(CONFIG_RVTRACE) += rvtrace-platform.o
+obj-$(CONFIG_RVTRACE) += rvtrace.o
+rvtrace-y := rvtrace-platform.o rvtrace-timestamp.o
 obj-$(CONFIG_RVTRACE_ENCODER) += rvtrace-encoder.o
 rvtrace-encoder-y := rvtrace-encoder-core.o rvtrace-encoder-sysfs.o
 obj-$(CONFIG_RVTRACE_RAMSINK) += rvtrace-ramsink.o
diff --git a/drivers/hwtracing/gtrace/rvtrace-encoder-core.c b/drivers/hwtracing/gtrace/rvtrace-encoder-core.c
index 17a3dde1314c..c0541fee6b93 100644
--- a/drivers/hwtracing/gtrace/rvtrace-encoder-core.c
+++ b/drivers/hwtracing/gtrace/rvtrace-encoder-core.c
@@ -127,6 +127,10 @@ static int rvtrace_encoder_probe(struct gtrace_component *comp)
    	val |= BIT(RVTRACE_COMPONENT_CTRL_INHIBITSRC_SHIFT);
    	gtrace_write32(pdata, val, RVTRACE_COMPONENT_CTRL_OFFSET);
    }
+
+	priv->has_timestamp = rvtrace_timestamp_reset(pdata) == 0;
+	if (priv->has_timestamp)
+		rvtrace_timestamp_init(pdata, &priv->ts_priv);
    dev_set_drvdata(&comp->dev, priv);
ret = gtrace_perf_symlink(comp, true);
@@ -155,6 +159,8 @@ static void rvtrace_encoder_parse_event_config(struct rvtrace_encoder_priv *priv
    u64 config = event->attr.config;
    enum rvtrace_encoder_syncmode syncmode;
+	if (priv->has_timestamp)
+		priv->ts_ctrl = config & BIT(GTRACE_PMU_ATTR_CFG_TIMESTAMP_SHIFT);
    if (priv->has_context)
    	priv->context = config & BIT(GTRACE_PMU_ATTR_CFG_CONTEXT_SHIFT);
@@ -170,11 +176,17 @@ static int rvtrace_encoder_start(struct gtrace_component *comp)
    struct rvtrace_encoder_priv *priv = dev_get_drvdata(&comp->dev);
    struct gtrace_platform_data *pdata = comp->pdata;
    struct gtrace_path *path = comp->path;
+	struct perf_event *event = NULL;
    int ret;
    u32 val;
-	if (path->mode == GTRACE_COMPONENT_MODE_PERF)
-		rvtrace_encoder_parse_event_config(priv, path->event);
+	if (path->mode == GTRACE_COMPONENT_MODE_PERF) {
+		event = path->event;
+		rvtrace_encoder_parse_event_config(priv, event);
+	}
+
+	if (priv->has_timestamp)
+		rvtrace_timestamp_setup(pdata, &priv->ts_priv, event, priv->ts_ctrl);
if (priv->srcbits)
    	rvtrace_encoder_set_srcid(pdata, priv->srcbits);
diff --git a/drivers/hwtracing/gtrace/rvtrace-encoder-sysfs.c b/drivers/hwtracing/gtrace/rvtrace-encoder-sysfs.c
index e973d0e43036..638759be2987 100644
--- a/drivers/hwtracing/gtrace/rvtrace-encoder-sysfs.c
+++ b/drivers/hwtracing/gtrace/rvtrace-encoder-sysfs.c
@@ -84,8 +84,40 @@ static ssize_t cpu_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(cpu);
+static ssize_t ts_ctrl_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_encoder_priv *priv = dev_get_drvdata(&comp->dev);
+
+	return sysfs_emit(buf, "%u\n", priv->ts_ctrl);
+}
+
+static ssize_t ts_ctrl_store(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t size)
+{
+	int ret;
+	unsigned long val;
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_encoder_priv *priv = dev_get_drvdata(&comp->dev);
+
+	if (!priv->has_timestamp)
+		return -EINVAL;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	priv->ts_ctrl = !!val;
+
+	return size;
+}
+static DEVICE_ATTR_RW(ts_ctrl);
+
 static struct attribute *rvtrace_encoder_attrs[] = {
    &dev_attr_cpu.attr,
+	&dev_attr_ts_ctrl.attr,
    NULL,
 };
@@ -285,6 +317,7 @@ const struct attribute_group *rvtrace_encoder_groups[] = {
    &rvtrace_encoder_mgmt_group,
    &rvtrace_encoder_control_group,
    &rvtrace_encoder_features_group,
+	&rvtrace_timestamp_group,
    NULL,
 };
 EXPORT_SYMBOL_GPL(rvtrace_encoder_groups);
diff --git a/drivers/hwtracing/gtrace/rvtrace-encoder.h b/drivers/hwtracing/gtrace/rvtrace-encoder.h
index 733d44c0e641..579567dabb3a 100644
--- a/drivers/hwtracing/gtrace/rvtrace-encoder.h
+++ b/drivers/hwtracing/gtrace/rvtrace-encoder.h
@@ -3,6 +3,8 @@
 #ifndef __RVTRACE_ENCODER_H__
 #define __RVTRACE_ENCODER_H__
+#include "rvtrace-timestamp.h"
+
 #define RVTRACE_COMPONENT_CTRL_ITRACE_SHIFT     2
 #define RVTRACE_COMPONENT_CTRL_INSTMODE_MASK	GENMASK(6, 4)
 #define RVTRACE_COMPONENT_CTRL_INSTMODE_OPIT	0x6
@@ -38,6 +40,9 @@ enum rvtrace_encoder_syncmode {
  * @has_context: Hardware flag for scontext/mcontext and privilege tracking.
  * @context:     Current configuration for scontext/mcontext and privilege tracking.
  * @boot_enable: Flag to automatically enable tracing on boot.
+ * @has_timestamp: Hardware flag indicating if timestamp generation is supported.
+ * @ts_ctrl:       Current configuration state of timestamp control.
+ * @ts_priv:       Private configuration data specific to the timestamp unit.
  */
 struct rvtrace_encoder_priv {
    bool syncmode_hw[RVTRACE_ENCODER_SYNCMODE_MAX];
@@ -48,6 +53,9 @@ struct rvtrace_encoder_priv {
    bool has_context;
    bool context;
    bool boot_enable;
+	bool has_timestamp;
+	bool ts_ctrl;
+	struct rvtrace_timestamp_priv ts_priv;
 };
#endif/* __RVTRACE_ENCODER_H__ */
diff --git a/drivers/hwtracing/gtrace/rvtrace-funnel.c b/drivers/hwtracing/gtrace/rvtrace-funnel.c
index 941cd3360395..c4b3396568f7 100644
--- a/drivers/hwtracing/gtrace/rvtrace-funnel.c
+++ b/drivers/hwtracing/gtrace/rvtrace-funnel.c
@@ -9,10 +9,28 @@
 #include "rvtrace.h"
 #include "rvtrace-funnel.h"
+static void rvtrace_funnel_parse_event_config(struct rvtrace_funnel_priv *priv,
+					      struct perf_event *event)
+{
+	u64 config = event->attr.config;
+
+	priv->ts_ctrl = config & BIT(GTRACE_PMU_ATTR_CFG_TIMESTAMP_SHIFT);
+}
+
 static int rvtrace_funnel_start(struct gtrace_component *comp)
 {
+	struct gtrace_path *path = comp->path;
+	struct rvtrace_funnel_priv *priv = dev_get_drvdata(&comp->dev);
+	struct perf_event *event = NULL;
    int ret;
+	if (path->mode == GTRACE_COMPONENT_MODE_PERF) {
+		event = path->event;
+		rvtrace_funnel_parse_event_config(priv, event);
+	}
+	if (priv->has_timestamp)
+		rvtrace_timestamp_setup(comp->pdata, &priv->ts_priv, event, priv->ts_ctrl);
+
    ret = gtrace_enable_component(comp);
    if (ret)
    	dev_err(&comp->dev, "failed to start rvtrace funnel.\n");
@@ -99,8 +117,40 @@ static ssize_t disinput_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(disinput);
+static ssize_t ts_ctrl_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_funnel_priv *priv = dev_get_drvdata(&comp->dev);
+
+	return sysfs_emit(buf, "%u\n", priv->ts_ctrl);
+}
+
+static ssize_t ts_ctrl_store(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t size)
+{
+	int ret;
+	unsigned long val;
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_funnel_priv *priv = dev_get_drvdata(&comp->dev);
+
+	if (!priv->has_timestamp)
+		return -EINVAL;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	priv->ts_ctrl = !!val;
+
+	return size;
+}
+static DEVICE_ATTR_RW(ts_ctrl);
+
 static struct attribute *rvtrace_funnel_attrs[] = {
    &dev_attr_disinput.attr,
+	&dev_attr_ts_ctrl.attr,
    NULL,
 };
@@ -110,6 +160,7 @@ static struct attribute_group rvtrace_funnel_group = {
const struct attribute_group *rvtrace_funnel_groups[] = {
    &rvtrace_funnel_group,
+	&rvtrace_timestamp_group,
    NULL,
 };
 EXPORT_SYMBOL_GPL(rvtrace_funnel_groups);
@@ -123,6 +174,10 @@ static int rvtrace_funnel_probe(struct gtrace_component *comp)
    if (!priv)
    	return -ENOMEM;
+	priv->has_timestamp = rvtrace_timestamp_reset(pdata) == 0;
+	if (priv->has_timestamp)
+		rvtrace_timestamp_init(pdata, &priv->ts_priv);
+
    gtrace_write32(pdata, RVTRACE_FUNNEL_DISINPUT_MASK, RVTRACE_FUNNEL_DISINPUT_OFFSET);
    priv->disinput_mask = gtrace_read32(pdata, RVTRACE_FUNNEL_DISINPUT_OFFSET);
    dev_set_drvdata(&comp->dev, priv);
diff --git a/drivers/hwtracing/gtrace/rvtrace-funnel.h b/drivers/hwtracing/gtrace/rvtrace-funnel.h
index 41547c8971ba..dddab5db8bef 100644
--- a/drivers/hwtracing/gtrace/rvtrace-funnel.h
+++ b/drivers/hwtracing/gtrace/rvtrace-funnel.h
@@ -6,16 +6,24 @@
 #ifndef __RVTRACE_HENNEL_H__
 #define __RVTRACE_HENNEL_H__
+#include "rvtrace-timestamp.h"
+
 #define RVTRACE_FUNNEL_DISINPUT_OFFSET	0x008
 #define RVTRACE_FUNNEL_DISINPUT_MASK	0xffff
/**
  * struct rvtrace_encoder_priv - Private driver data for the rvtrace funnel
  * @disinput_mask: Bitmask of inputs supporting disable.
+ * @has_timestamp: Hardware flag indicating if timestamp generation is supported.
+ * @ts_ctrl:       Current configuration state of timestamp control.
+ * @ts_priv:       Private configuration data specific to the timestamp unit.
  */
struct rvtrace_funnel_priv {
    u32 disinput_mask;
+	bool has_timestamp;
+	bool ts_ctrl;
+	struct rvtrace_timestamp_priv ts_priv;
 };
#endif /* __RVTRACE_ENCODER_H__ */
diff --git a/drivers/hwtracing/gtrace/rvtrace-timestamp.c b/drivers/hwtracing/gtrace/rvtrace-timestamp.c
new file mode 100644
index 000000000000..0ec7436add16
--- /dev/null
+++ b/drivers/hwtracing/gtrace/rvtrace-timestamp.c
@@ -0,0 +1,336 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(C) 2026 Spacemit Technologies, Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/gtrace.h>
+#include <linux/bitfield.h>
+#include "rvtrace.h"
+#include "rvtrace-timestamp.h"
+#include "rvtrace-encoder.h"
+#include "rvtrace-funnel.h"
+
+int rvtrace_timestamp_reset(struct gtrace_platform_data *pdata)
+{
+	gtrace_write32(pdata, 0, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+	gtrace_write32(pdata, RVTRACE_COMPONENT_CTRL_ACTIVE_MASK, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+	return gtrace_poll_bit(pdata, RVTRACE_TIMESTAMP_CTRL_OFFSET,
+			       RVTRACE_COMPONENT_CTRL_ACTIVE_SHIFT, 1,
+			       pdata->control_poll_timeout_usecs);
+}
+EXPORT_SYMBOL_GPL(rvtrace_timestamp_reset);
+
+void rvtrace_timestamp_init(struct gtrace_platform_data *pdata,
+			    struct rvtrace_timestamp_priv *priv)
+{
+	u32 ctrl, val;
+	enum rvtrace_timestamp_mode mode;
+
+	ctrl = gtrace_read32(pdata, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+	priv->mode = FIELD_GET(RVTRACE_TIMESTAMP_MODE_MASK, ctrl);
+
+	/* get timestamp mode hw */
+	for (mode = RVTRACE_TIMESTAMP_MODE_NONE; mode < RVTRACE_TIMESTAMP_MODE_MAX; mode++) {
+		val = ctrl & ~RVTRACE_TIMESTAMP_MODE_MASK;
+		val |= FIELD_PREP(RVTRACE_TIMESTAMP_MODE_MASK, mode);
+		gtrace_write32(pdata, val, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+		val = gtrace_read32(pdata, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+		val = FIELD_GET(RVTRACE_TIMESTAMP_MODE_MASK, val);
+		priv->mode_hw[mode] = (mode == val);
+	}
+
+	gtrace_write32(pdata, ctrl, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+}
+EXPORT_SYMBOL_GPL(rvtrace_timestamp_init);
+
+static bool rvtrace_timestamp_is_internal(struct rvtrace_timestamp_priv *priv)
+{
+	return (priv->mode == RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM ||
+		priv->mode == RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE);
+}
+
+static void rvtrace_timestamp_parse_event_config(struct rvtrace_timestamp_priv *priv,
+						 struct perf_event *event)
+{
+	u64 config = event->attr.config;
+
+	if (priv->mode_hw[FIELD_GET(GTRACE_PMU_ATTR_CFG_TSMODE_MASK, config)])
+		priv->mode = FIELD_GET(GTRACE_PMU_ATTR_CFG_TSMODE_MASK, config);
+	if (rvtrace_timestamp_is_internal(priv))
+		priv->prescale = FIELD_GET(GTRACE_PMU_ATTR_CFG_TSPRESCALE_MASK, config);
+}
+
+void rvtrace_timestamp_setup(struct gtrace_platform_data *pdata,
+			     struct rvtrace_timestamp_priv *priv,
+			     struct perf_event *event,
+			     bool enable)
+{
+	u32 val;
+
+	if (event)
+		rvtrace_timestamp_parse_event_config(priv, event);
+
+	val = gtrace_read32(pdata, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+	val &= ~RVTRACE_TIMESTAMP_MODE_MASK;
+	val &= ~RVTRACE_TIMESTAMP_PRESCALE_MASK;
+	val |= FIELD_PREP(RVTRACE_TIMESTAMP_MODE_MASK, priv->mode);
+	val |= FIELD_PREP(RVTRACE_TIMESTAMP_PRESCALE_MASK, priv->prescale);
+
+	val &= ~BIT(RVTRACE_TIMESTAMP_COUNT_SHIFT);
+	val &= ~BIT(RVTRACE_TIMESTAMP_ENABLE_SHIFT);
+	if (enable) {
+		val |= BIT(RVTRACE_TIMESTAMP_COUNT_SHIFT);
+		val |= BIT(RVTRACE_TIMESTAMP_ENABLE_SHIFT);
+	}
+
+	gtrace_write32(pdata, val, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+}
+EXPORT_SYMBOL_GPL(rvtrace_timestamp_setup);
+
+static struct rvtrace_timestamp_priv *get_timestamp_priv(struct gtrace_component *comp)
+{
+	enum gtrace_component_type gtype = comp->id.type;
+
+	if (gtype == GTRACE_RVTRACE_ENCODER) {
+		struct rvtrace_encoder_priv *priv = dev_get_drvdata(&comp->dev);
+		return &priv->ts_priv;
+	} else if (gtype == GTRACE_RVTRACE_FUNNEL) {
+		struct rvtrace_funnel_priv *priv = dev_get_drvdata(&comp->dev);
+		return &priv->ts_priv;
+	}
+
+	return NULL;
+}
+
+static struct gtrace_component *rvtrace_find_funnel(struct gtrace_component *comp)
+{
+	struct gtrace_platform_data *pdata = comp->pdata;
+	struct gtrace_connection *conn = NULL;
+	int i;
+
+	if (comp->id.type == GTRACE_RVTRACE_FUNNEL)
+		return comp;
+
+	if (!pdata->nr_outconns)
+		return NULL;
+
+	for (i = 0; i < pdata->nr_outconns; i++) {
+		conn = pdata->outconns[i];
+		if (conn && conn->dest_comp)
+			break;
+	}
+
+	if (!conn)
+		return NULL;
+
+	return rvtrace_find_funnel(conn->dest_comp);
+}
+
+static struct gtrace_component *rvtrace_timestamp_get_source(struct gtrace_component *comp)
+{
+	struct gtrace_component *dest = comp;
+
+	if (dest->id.type == GTRACE_RVTRACE_ENCODER) {
+		struct rvtrace_encoder_priv *priv = dev_get_drvdata(&dest->dev);
+
+		if (priv && priv->has_timestamp)
+			return dest;
+
+		dest = rvtrace_find_funnel(dest);
+		if (!dest)
+			return NULL;
+	}
+
+	if (dest->id.type == GTRACE_RVTRACE_FUNNEL) {
+		struct rvtrace_funnel_priv *priv = dev_get_drvdata(&dest->dev);
+
+		if (priv && priv->has_timestamp)
+			return dest;
+	}
+
+	return NULL;
+}
+
+static ssize_t source_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	return sysfs_emit(buf, "%s\n", dev_name(&comp->dev));
+}
+static DEVICE_ATTR_RO(source);
+
+static const char * const modes_str[] = {
+	[RVTRACE_TIMESTAMP_MODE_NONE] = "none",
+	[RVTRACE_TIMESTAMP_MODE_EXTERNAL] = "external",
+	[RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM] = "internal_system",
+	[RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE] = "internal_core",
+	[RVTRACE_TIMESTAMP_MODE_SHARED] = "shared",
+};
+
+static ssize_t modes_available_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_timestamp_priv *priv;
+	enum rvtrace_timestamp_mode mode;
+	ssize_t size = 0;
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	priv = get_timestamp_priv(comp);
+
+	for (mode = RVTRACE_TIMESTAMP_MODE_NONE; mode < RVTRACE_TIMESTAMP_MODE_MAX; mode++) {
+		if (priv->mode_hw[mode])
+			size += sysfs_emit_at(buf, size, "%s ", modes_str[mode]);
+	}
+
+	size += sysfs_emit_at(buf, size, "\n");
+	return size;
+}
+static DEVICE_ATTR_RO(modes_available);
+
+static ssize_t mode_preferred_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_timestamp_priv *priv;
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	priv = get_timestamp_priv(comp);
+
+	return sysfs_emit(buf, "%s\n", modes_str[priv->mode]);
+}
+
+static ssize_t mode_preferred_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t size)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_timestamp_priv *priv;
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	priv = get_timestamp_priv(comp);
+
+	if (sysfs_streq(buf, modes_str[RVTRACE_TIMESTAMP_MODE_NONE]) &&
+			priv->mode_hw[RVTRACE_TIMESTAMP_MODE_NONE])
+		priv->mode = RVTRACE_TIMESTAMP_MODE_NONE;
+	else if (sysfs_streq(buf, modes_str[RVTRACE_TIMESTAMP_MODE_EXTERNAL]) &&
+			priv->mode_hw[RVTRACE_TIMESTAMP_MODE_EXTERNAL])
+		priv->mode = RVTRACE_TIMESTAMP_MODE_EXTERNAL;
+	else if (sysfs_streq(buf, modes_str[RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM]) &&
+			priv->mode_hw[RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM])
+		priv->mode = RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM;
+	else if (sysfs_streq(buf, modes_str[RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE]) &&
+			priv->mode_hw[RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE])
+		priv->mode = RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE;
+	else if (sysfs_streq(buf, modes_str[RVTRACE_TIMESTAMP_MODE_SHARED]) &&
+			priv->mode_hw[RVTRACE_TIMESTAMP_MODE_SHARED])
+		priv->mode = RVTRACE_TIMESTAMP_MODE_SHARED;
+	else
+		return -EINVAL;
+	return size;
+}
+static DEVICE_ATTR_RW(mode_preferred);
+
+static ssize_t prescale_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_timestamp_priv *priv;
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	priv = get_timestamp_priv(comp);
+
+	return sysfs_emit(buf, "%u\n", priv->prescale);
+}
+
+static ssize_t prescale_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct gtrace_component *comp = to_gtrace_component(dev);
+	struct rvtrace_timestamp_priv *priv;
+	unsigned long val;
+	int ret;
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > RVTRACE_TIMESTAMP_PRESCALE_MAX)
+		return -EINVAL;
+
+	priv = get_timestamp_priv(comp);
+	if (!rvtrace_timestamp_is_internal(priv))
+		return -EINVAL;
+
+	priv->prescale = val;
+
+	return size;
+}
+static DEVICE_ATTR_RW(prescale);
+
+static ssize_t control_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	u32 val;
+	struct gtrace_component *comp = to_gtrace_component(dev);
+
+	comp = rvtrace_timestamp_get_source(comp);
+	if (!comp)
+		return -EINVAL;
+
+	val = gtrace_read32(comp->pdata, RVTRACE_TIMESTAMP_CTRL_OFFSET);
+
+	return sysfs_emit(buf, "0x%x\n", val);
+}
+static DEVICE_ATTR_RO(control);
+
+static struct attribute *rvtrace_timestamp_attrs[] = {
+	&dev_attr_source.attr,
+	&dev_attr_modes_available.attr,
+	&dev_attr_mode_preferred.attr,
+	&dev_attr_prescale.attr,
+	&dev_attr_control.attr,
+	NULL,
+};
+
+static umode_t timestamp_attr_is_visible(struct kobject *kobj,
+					 struct attribute *attr, int idx)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct gtrace_component *comp = to_gtrace_component(dev);
+
+	if (rvtrace_timestamp_get_source(comp))
+		return attr->mode;
+
+	return 0;
+}
+
+struct attribute_group rvtrace_timestamp_group = {
+	.attrs = rvtrace_timestamp_attrs,
+	.name = "timestamp",
+	.is_visible = timestamp_attr_is_visible,
+};
+EXPORT_SYMBOL_GPL(rvtrace_timestamp_group);
diff --git a/drivers/hwtracing/gtrace/rvtrace-timestamp.h b/drivers/hwtracing/gtrace/rvtrace-timestamp.h
new file mode 100644
index 000000000000..75924d397996
--- /dev/null
+++ b/drivers/hwtracing/gtrace/rvtrace-timestamp.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(C) 2026 Spacemit Technologies, Inc.
+ */
+
+#ifndef __RVTRACE_TIMESTAMP_H__
+#define __RVTRACE_TIMESTAMP_H__
+
+#include <linux/types.h>
+
+#define RVTRACE_TIMESTAMP_CTRL_OFFSET		0x040
+#define RVTRACE_TIMESTAMP_COUNT_SHIFT		1
+#define RVTRACE_TIMESTAMP_MODE_MASK		GENMASK(6, 4)
+#define RVTRACE_TIMESTAMP_PRESCALE_MASK		GENMASK(9, 8)
+#define RVTRACE_TIMESTAMP_PRESCALE_MAX		3
+#define RVTRACE_TIMESTAMP_ENABLE_SHIFT		15
+#define RVTRACE_TIMESTAMP_WIDTH_MASK		GENMASK(29, 24)
+
+enum rvtrace_timestamp_mode {
+	RVTRACE_TIMESTAMP_MODE_NONE,
+	RVTRACE_TIMESTAMP_MODE_EXTERNAL,
+	RVTRACE_TIMESTAMP_MODE_INTERNAL_SYSTEM,
+	RVTRACE_TIMESTAMP_MODE_INTERNAL_CORE,
+	RVTRACE_TIMESTAMP_MODE_SHARED,
+	RVTRACE_TIMESTAMP_MODE_MAX
+};
+
+struct rvtrace_timestamp_priv {
+	bool mode_hw[RVTRACE_TIMESTAMP_MODE_MAX];
+	enum rvtrace_timestamp_mode mode;
+	u32 prescale;
+};
+
+int rvtrace_timestamp_reset(struct gtrace_platform_data *pdata);
+void rvtrace_timestamp_init(struct gtrace_platform_data *pdata,
+			    struct rvtrace_timestamp_priv *priv);
+void rvtrace_timestamp_setup(struct gtrace_platform_data *pdata,
+			     struct rvtrace_timestamp_priv *priv,
+			     struct perf_event *event,
+			     bool enable);
+
+extern struct attribute_group rvtrace_timestamp_group;
+
+#endif/* __RVTRACE_TIMESTAMP_H__ */
-- 
2.34.1


    

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[PATCH 11/24] gtrace: Add RISC-V trace timestamp support