coresight: Add helper for atomically taking the device

Now that mode is in struct coresight_device, this pattern can be wrapped
in a helper.

Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20240129154050.569566-11-james.clark@arm.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
This commit is contained in:
James Clark 2024-01-29 15:40:41 +00:00 committed by Suzuki K Poulose
parent 812265e26e
commit d724f65218
4 changed files with 20 additions and 15 deletions

View File

@ -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:

View File

@ -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:

View File

@ -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);

View File

@ -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);