[PATCH 09/24] gtrace: Add port-level start/stop driver callbacks
From: Zane Leung
Date: Thu Oct 22 2026 - 23:17:43 EST
Add start_port() and stop_port() callbacks to gtrace_driver so
multi-port link components like funnel and replicator can enable a
specific input/output port the first time a path uses it, tracked by
the per-connection src_refcnt/dest_refcnt fields.
Signed-off-by: Zane Leung <liangzhen@xxxxxxxxxxxxxxxxxx>
---
drivers/hwtracing/gtrace/gtrace-core.c | 66 ++++++++++++++++++++------
include/linux/gtrace.h | 12 +++++
2 files changed, 64 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/gtrace/gtrace-core.c b/drivers/hwtracing/gtrace/gtrace-core.c
index 3f55d8b7302d..231d06218d8e 100644
--- a/drivers/hwtracing/gtrace/gtrace-core.c
+++ b/drivers/hwtracing/gtrace/gtrace-core.c
@@ -654,7 +654,9 @@ static void gtrace_release_path_nodes(struct gtrace_path *path)
}
static int __gtrace_comp_start(struct gtrace_component *comp,
- struct gtrace_path *path)
+ struct gtrace_path *path,
+ struct gtrace_connection *inconn,
+ struct gtrace_connection *outconn)
{
struct gtrace_comp_priv *cpriv = to_gtrace_comp_priv(comp);
const struct gtrace_driver *gtdrv = to_gtrace_driver(comp->dev.driver);
@@ -690,6 +692,12 @@ static int __gtrace_comp_start(struct gtrace_component *comp,
cpriv->owner = task_pid_nr(path->event->owner);
}
+ if (gtdrv->start_port) {
+ ret = gtdrv->start_port(comp, inconn, outconn);
+ if (ret)
+ goto out;
+ }
+
cpriv->start_count++;
out:
raw_spin_unlock_irqrestore(&cpriv->lock, flags);
@@ -697,7 +705,9 @@ static int __gtrace_comp_start(struct gtrace_component *comp,
}
static int __gtrace_comp_stop(struct gtrace_component *comp,
- struct gtrace_path *path)
+ struct gtrace_path *path,
+ struct gtrace_connection *inconn,
+ struct gtrace_connection *outconn)
{
struct gtrace_comp_priv *cpriv = to_gtrace_comp_priv(comp);
const struct gtrace_driver *gtdrv = to_gtrace_driver(comp->dev.driver);
@@ -715,13 +725,16 @@ static int __gtrace_comp_stop(struct gtrace_component *comp,
goto out;
}
+ if (!gtdrv) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ if (gtdrv->stop_port)
+ gtdrv->stop_port(comp, inconn, outconn);
+
cpriv->start_count--;
if (!cpriv->start_count) {
- if (!gtdrv) {
- ret = -ENODEV;
- goto out;
- }
-
if (gtdrv->stop)
ret = gtdrv->stop(comp);
comp->path = NULL;
@@ -734,19 +747,36 @@ static int __gtrace_comp_stop(struct gtrace_component *comp,
int gtrace_path_start(struct gtrace_path *path)
{
- struct gtrace_path_node *node;
+ struct gtrace_path_node *node, *prev;
+ struct gtrace_connection *inconn;
int ret = 0;
list_for_each_entry_reverse(node, &path->comp_list, head) {
- ret = __gtrace_comp_start(node->comp, path);
+ if (node->comp == gtrace_path_source(path)) {
+ inconn = NULL;
+ } else {
+ prev = list_prev_entry(node, head);
+ inconn = prev->conn;
+ }
+
+ ret = __gtrace_comp_start(node->comp, path, inconn, node->conn);
if (ret)
break;
}
/* If a component failed to start, stop all the components that were started before it */
- if (ret)
- list_for_each_entry_continue(node, &path->comp_list, head)
- __gtrace_comp_stop(node->comp, path);
+ if (ret) {
+ list_for_each_entry_continue(node, &path->comp_list, head) {
+ if (node->comp == gtrace_path_source(path)) {
+ inconn = NULL;
+ } else {
+ prev = list_prev_entry(node, head);
+ inconn = prev->conn;
+ }
+
+ __gtrace_comp_stop(node->comp, path, inconn, node->conn);
+ }
+ }
return ret;
}
@@ -754,11 +784,19 @@ EXPORT_SYMBOL_GPL(gtrace_path_start);
int gtrace_path_stop(struct gtrace_path *path)
{
- struct gtrace_path_node *node;
+ struct gtrace_path_node *node, *prev;
+ struct gtrace_connection *inconn;
int ret = 0, err;
list_for_each_entry(node, &path->comp_list, head) {
- err = __gtrace_comp_stop(node->comp, path);
+ if (node->comp == gtrace_path_source(path)) {
+ inconn = NULL;
+ } else {
+ prev = list_prev_entry(node, head);
+ inconn = prev->conn;
+ }
+
+ err = __gtrace_comp_stop(node->comp, path, inconn, node->conn);
if (err && !ret)
ret = err;
}
diff --git a/include/linux/gtrace.h b/include/linux/gtrace.h
index 4bbe5ac835ec..ee60585ef65c 100644
--- a/include/linux/gtrace.h
+++ b/include/linux/gtrace.h
@@ -55,9 +55,11 @@ enum gtrace_format {
* @src_port: A connection's source port number.
* @src_fwnode: Source component's fwnode handle.
* @src_comp: Source component's pointer.
+ * @src_refcnt: Number of paths currently using this connection's source port.
* @dest_port: A connection's destination port number.
* @dest_fwnode: Destination component's fwnode handle.
* @dest_comp: Destination component's pointer.
+ * @dest_refcnt: Number of paths currently routing data into the destination port.
*/
struct gtrace_connection {
int src_port;
@@ -66,6 +68,8 @@ struct gtrace_connection {
struct fwnode_handle *dest_fwnode;
struct gtrace_component *src_comp;
struct gtrace_component *dest_comp;
+ u32 src_refcnt;
+ u32 dest_refcnt;
};
struct gtrace_platform_data;
@@ -363,6 +367,8 @@ int gtrace_path_copyto_auxbuf(struct gtrace_path *path,
* via @format (see PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK).
* @start: Callback to start tracing.
* @stop: Callback to stop tracing.
+ * @start_port: Callback to start a specific component port.
+ * @stop_port: Callback to stop a specific component port.
* @probe: Driver probe() function.
* @remove: Driver remove() function.
* @get_trace_id: Get/allocate a trace ID.
@@ -376,6 +382,12 @@ struct gtrace_driver {
u64 *format);
int (*start)(struct gtrace_component *comp);
int (*stop)(struct gtrace_component *comp);
+ int (*start_port)(struct gtrace_component *comp,
+ struct gtrace_connection *inconn,
+ struct gtrace_connection *outconn);
+ void (*stop_port)(struct gtrace_component *comp,
+ struct gtrace_connection *inconn,
+ struct gtrace_connection *outconn);
int (*probe)(struct gtrace_component *comp);
void (*remove)(struct gtrace_component *comp);
int (*get_trace_id)(struct gtrace_component *comp,
--
2.34.1