Except for software sources (e.g. STM), other sources treat multiple enables as equivalent to a single enable. The device mode already tracks the binary state, so it is redundant to operate refcount.
Introduce a helper coresight_is_software_source() for check software source. Refactor to maintain the refcount only for software sources. This simplifies future CPU PM handling without refcount logic.
Tested-by: James Clark james.clark@linaro.org Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Reviewed-by: James Clark james.clark@linaro.org Tested-by: Jie Gan jie.gan@oss.qualcomm.com Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-sysfs.c | 39 +++++++++++++++++---------- include/linux/coresight.h | 6 +++++ 2 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c index 21196ee1d2bdf6ccba4afbde2c188432bc4932b1..80b6b634a70d3cec98dfa3e5fd146cd254b96d6f 100644 --- a/drivers/hwtracing/coresight/coresight-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-sysfs.c @@ -39,6 +39,26 @@ ssize_t coresight_simple_show32(struct device *_dev, } EXPORT_SYMBOL_GPL(coresight_simple_show32);
+static void coresight_source_get_refcnt(struct coresight_device *csdev) +{ + /* + * There could be multiple applications driving the software + * source. So keep the refcount for each such user when the + * source is already enabled. + * + * No need to increment the reference counter for other source + * types, as multiple enables are the same as a single enable. + */ + if (coresight_is_software_source(csdev)) + csdev->refcnt++; +} + +static void coresight_source_put_refcnt(struct coresight_device *csdev) +{ + if (coresight_is_software_source(csdev)) + csdev->refcnt--; +} + static int coresight_enable_source_sysfs(struct coresight_device *csdev, enum cs_mode mode, struct coresight_path *path) @@ -57,14 +77,14 @@ static int coresight_enable_source_sysfs(struct coresight_device *csdev, return ret; }
- csdev->refcnt++; + coresight_source_get_refcnt(csdev);
return 0; }
/** - * coresight_disable_source_sysfs - Drop the reference count by 1 and disable - * the device if there are no users left. + * coresight_disable_source_sysfs - Drop the reference count by 1 for software + * sources. Disable the device if there are no users left. * * @csdev: The coresight device to disable * @data: Opaque data to pass on to the disable function of the source device. @@ -79,7 +99,7 @@ static bool coresight_disable_source_sysfs(struct coresight_device *csdev, if (coresight_get_mode(csdev) != CS_MODE_SYSFS) return false;
- csdev->refcnt--; + coresight_source_put_refcnt(csdev); if (csdev->refcnt == 0) { coresight_disable_source(csdev, data); return true; @@ -156,9 +176,6 @@ int coresight_enable_sysfs(struct coresight_device *csdev) int ret = 0; struct coresight_device *sink; struct coresight_path *path; - enum coresight_dev_subtype_source subtype; - - subtype = csdev->subtype.source_subtype;
mutex_lock(&coresight_mutex);
@@ -173,13 +190,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev) * doesn't hold coresight_mutex. */ if (coresight_get_mode(csdev) == CS_MODE_SYSFS) { - /* - * There could be multiple applications driving the software - * source. So keep the refcount for each such user when the - * source is already enabled. - */ - if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) - csdev->refcnt++; + coresight_source_get_refcnt(csdev); goto out; }
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 58d474b269806d32cad6ed87da96550b06f1f30f..76ef4c0965125cd11830df0151a6707d3e3b638d 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -611,6 +611,12 @@ static inline bool coresight_is_percpu_source(struct coresight_device *csdev) (csdev->subtype.source_subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_PROC); }
+static inline bool coresight_is_software_source(struct coresight_device *csdev) +{ + return csdev && coresight_is_device_source(csdev) && + (csdev->subtype.source_subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE); +} + static inline bool coresight_is_percpu_sink(struct coresight_device *csdev) { return csdev && (csdev->type == CORESIGHT_DEV_TYPE_SINK) &&