Now that mode is in struct coresight_device, this pattern can be wrapped
in a helper.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-etm3x-core.c | 8 +++-----
drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 +++-----
drivers/hwtracing/coresight/coresight-stm.c | 8 +++-----
include/linux/coresight.h | 11 +++++++++++
4 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index a8be115636f0..ce2b3ed90fb9 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -556,14 +556,12 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
enum cs_mode mode)
{
int ret;
- u32 val;
struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- val = local_cmpxchg(&drvdata->csdev->mode, CS_MODE_DISABLED, mode);
-
- /* Someone is already using the tracer */
- if (val)
+ if (!coresight_take_mode(csdev, mode)) {
+ /* Someone is already using the tracer */
return -EBUSY;
+ }
switch (mode) {
case CS_MODE_SYSFS:
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 3480b563981c..8fca7fc379e6 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -840,13 +840,11 @@ static int etm4_enable(struct coresight_device *csdev, struct perf_event *event,
enum cs_mode mode)
{
int ret;
- u32 val;
- val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode);
-
- /* Someone is already using the tracer */
- if (val)
+ if (!coresight_take_mode(csdev, mode)) {
+ /* Someone is already using the tracer */
return -EBUSY;
+ }
switch (mode) {
case CS_MODE_SYSFS:
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index af9b21224246..80fed4c377f1 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -193,17 +193,15 @@ static void stm_enable_hw(struct stm_drvdata *drvdata)
static int stm_enable(struct coresight_device *csdev, struct perf_event *event,
enum cs_mode mode)
{
- u32 val;
struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
if (mode != CS_MODE_SYSFS)
return -EINVAL;
- val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode);
-
- /* Someone is already using the tracer */
- if (val)
+ if (!coresight_take_mode(csdev, mode)) {
+ /* Someone is already using the tracer */
return -EBUSY;
+ }
pm_runtime_get_sync(csdev->dev.parent);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index c5be46d7f85c..175d184b3a1b 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -580,6 +580,17 @@ static inline bool coresight_is_percpu_sink(struct coresight_device *csdev)
(csdev->subtype.sink_subtype == CORESIGHT_DEV_SUBTYPE_SINK_PERCPU_SYSMEM);
}
+/*
+ * Atomically try to take the device and set a new mode. Returns true on
+ * success, false if the device is already taken by someone else.
+ */
+static inline bool coresight_take_mode(struct coresight_device *csdev,
+ enum cs_mode new_mode)
+{
+ return local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, new_mode) ==
+ CS_MODE_DISABLED;
+}
+
extern struct coresight_device *
coresight_register(struct coresight_desc *desc);
extern void coresight_unregister(struct coresight_device *csdev);
--
2.34.1