[PATCH v10 05/20] coresight: etm4x: Set per-CPU path on local CPU

[Leo Yan]

Introduce the coresight_set_percpu_local_path() helper to set the path
pointer on the local CPU.  This helper is used during ETMv4 enable and
disable operations.

Tested-by: James Clark <james.clark at linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun at arm.com>
Reviewed-by: James Clark <james.clark at linaro.org>
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-core.c       |  8 ++++++++
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 18 +++++++++++++++---
 drivers/hwtracing/coresight/coresight-priv.h       |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 6907da35ed02fa58f8d30f5576627a6ce3b88362..74c9f0dd43784dd735885249c1e50fc86f610582 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -35,6 +35,8 @@
 DEFINE_MUTEX(coresight_mutex);
 static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
 
+static DEFINE_PER_CPU(struct coresight_path *, percpu_path);
+
 /**
  * struct coresight_node - elements of a path, from source to sink
  * @csdev:	Address of an element.
@@ -423,6 +425,12 @@ int coresight_resume_source(struct coresight_device *csdev)
 }
 EXPORT_SYMBOL_GPL(coresight_resume_source);
 
+void coresight_set_percpu_local_path(struct coresight_path *path)
+{
+	this_cpu_write(percpu_path, path);
+}
+EXPORT_SYMBOL_GPL(coresight_set_percpu_local_path);
+
 /*
  * coresight_disable_path_from : Disable components in the given path beyond
  * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index a776ebb3b2b0360c99a8dadacfde4c2303dd59d6..7b91fab9895d7b2a65ebb1161b117d9d3f5fca1b 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -234,6 +234,7 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
 
 struct etm4_enable_arg {
 	struct etmv4_drvdata *drvdata;
+	struct coresight_path *path;
 	int rc;
 };
 
@@ -621,8 +622,12 @@ static void etm4_enable_sysfs_smp_call(void *info)
 	arg->rc = etm4_enable_hw(arg->drvdata);
 
 	/* The tracer didn't start */
-	if (arg->rc)
+	if (arg->rc) {
 		coresight_set_mode(csdev, CS_MODE_DISABLED);
+		return;
+	}
+
+	coresight_set_percpu_local_path(arg->path);
 }
 
 /*
@@ -890,9 +895,13 @@ static int etm4_enable_perf(struct coresight_device *csdev,
 
 out:
 	/* Failed to start tracer; roll back to DISABLED mode */
-	if (ret)
+	if (ret) {
 		coresight_set_mode(csdev, CS_MODE_DISABLED);
-	return ret;
+		return ret;
+	}
+
+	coresight_set_percpu_local_path(path);
+	return 0;
 }
 
 static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
@@ -922,6 +931,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa
 	 * ensures that register writes occur when cpu is powered.
 	 */
 	arg.drvdata = drvdata;
+	arg.path = path;
 	ret = smp_call_function_single(drvdata->cpu,
 				       etm4_enable_sysfs_smp_call, &arg, 1);
 	if (!ret)
@@ -1063,6 +1073,7 @@ static void etm4_disable_sysfs_smp_call(void *info)
 
 	etm4_disable_hw(drvdata);
 
+	coresight_set_percpu_local_path(NULL);
 	coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
 }
 
@@ -1092,6 +1103,7 @@ static int etm4_disable_perf(struct coresight_device *csdev,
 	/* TRCVICTLR::SSSTATUS, bit[9] */
 	filters->ssstatus = (control & BIT(9));
 
+	coresight_set_percpu_local_path(NULL);
 	coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
 
 	/*
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 1ea882dffd703b2873e41b4ce0c2564d2ce9bbad..ff8a720339deb854ac3b4eb916f49e844f442d34 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -251,5 +251,6 @@ struct coresight_device *coresight_get_percpu_sink(int cpu);
 void coresight_disable_source(struct coresight_device *csdev, void *data);
 void coresight_pause_source(struct coresight_device *csdev);
 int coresight_resume_source(struct coresight_device *csdev);
+void coresight_set_percpu_local_path(struct coresight_path *path);
 
 #endif

-- 
2.34.1