diff mbox series

[v2,4/5] coresight: configfs: Allow configfs to activate configuration

Message ID 20211019191351.10242-5-mike.leach@linaro.org (mailing list archive)
State New, archived
Headers show
Series coresight: syscfg: dynamic load | expand

Commit Message

Mike Leach Oct. 19, 2021, 7:13 p.m. UTC 
Adds configfs attributes to allow a configuration to be enabled for use
when sysfs is used to control CoreSight.

perf retains independent enabling of configurations.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 .../coresight/coresight-etm4x-core.c          |  11 +-
 .../coresight/coresight-syscfg-configfs.c     |  67 ++++++++++
 .../coresight/coresight-syscfg-configfs.h     |   2 +
 .../hwtracing/coresight/coresight-syscfg.c    | 126 ++++++++++++++----
 .../hwtracing/coresight/coresight-syscfg.h    |   8 +-
 5 files changed, 186 insertions(+), 28 deletions(-)

Comments

Mathieu Poirier Nov. 11, 2021, 5:23 p.m. UTC | #1 
Good day Mike,

On Tue, Oct 19, 2021 at 08:13:50PM +0100, Mike Leach wrote:
> Adds configfs attributes to allow a configuration to be enabled for use
> when sysfs is used to control CoreSight.
> 
> perf retains independent enabling of configurations.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
>  .../coresight/coresight-etm4x-core.c          |  11 +-
>  .../coresight/coresight-syscfg-configfs.c     |  67 ++++++++++
>  .../coresight/coresight-syscfg-configfs.h     |   2 +
>  .../hwtracing/coresight/coresight-syscfg.c    | 126 ++++++++++++++----
>  .../hwtracing/coresight/coresight-syscfg.h    |   8 +-
>  5 files changed, 186 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 86a313857b58..bf18128cf5de 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -722,7 +722,16 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>  {
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>  	struct etm4_enable_arg arg = { };
> -	int ret;
> +	unsigned long cfg_hash;
> +	int ret, preset;
> +
> +	/* enable any config activated by configfs */
> +	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
> +	if (cfg_hash) {
> +		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	spin_lock(&drvdata->spinlock);
>  
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> index 345a62f1b728..c388a77a2683 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> @@ -6,6 +6,7 @@
>  
>  #include <linux/configfs.h>
>  
> +#include "coresight-config.h"
>  #include "coresight-syscfg-configfs.h"
>  
>  /* create a default ci_type. */
> @@ -87,9 +88,75 @@ static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page)
>  }
>  CONFIGFS_ATTR_RO(cscfg_cfg_, values);
>  
> +static ssize_t cscfg_cfg_activate_show(struct config_item *item, char *page)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +
> +	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->active);
> +}
> +
> +static ssize_t cscfg_cfg_activate_store(struct config_item *item,
> +					const char *page, size_t count)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +	int err;
> +	bool val;
> +
> +	err = kstrtobool(page, &val);
> +	if (!err)
> +		err = cscfg_config_sysfs_activate(fs_config->config_desc, val);
> +	if (!err) {
> +		fs_config->active = val;
> +		if (val)
> +			cscfg_config_sysfs_set_preset(fs_config->preset);
> +	}
> +	return err ? err : count;
> +}
> +CONFIGFS_ATTR(cscfg_cfg_, activate);

I would call this "enable" to follow what is already done for coresight in
sysfs.

> +
> +static ssize_t cscfg_cfg_active_preset_show(struct config_item *item, char *page)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +
> +	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->preset);
> +}
> +
> +static ssize_t cscfg_cfg_active_preset_store(struct config_item *item,
> +					     const char *page, size_t count)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +	int preset, err;
> +
> +	err = kstrtoint(page, 0, &preset);
> +	if (!err) {
> +		/*
> +		 * presets start at 1, and go up to max (15),
> +		 * but the config may provide fewer.
> +		 */
> +		if ((preset < 1) || (preset > fs_config->config_desc->nr_presets))
> +			err = -EINVAL;
> +	}
> +
> +	if (!err) {
> +		/* set new value */
> +		fs_config->preset = preset;
> +		/* set on system if active */
> +		if (fs_config->active)
> +			cscfg_config_sysfs_set_preset(fs_config->preset);
> +	}
> +	return err ? err : count;
> +}
> +CONFIGFS_ATTR(cscfg_cfg_, active_preset);

And I would call this "preset" since this is what is used on the perf cmd line.

Please add a new "Using Configurations from configfs" section in [1] to
show how "enable" and "preset" should be used.

With that:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>


[1]. Documentation/trace/coresight/coresight-config.rst

> +
>  static struct configfs_attribute *cscfg_config_view_attrs[] = {
>  	&cscfg_cfg_attr_description,
>  	&cscfg_cfg_attr_feature_refs,
> +	&cscfg_cfg_attr_activate,
> +	&cscfg_cfg_attr_active_preset,
>  	NULL,
>  };
>  
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> index ea1e54d29f7f..373d84d43268 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> @@ -15,6 +15,8 @@
>  struct cscfg_fs_config {
>  	struct cscfg_config_desc *config_desc;
>  	struct config_group group;
> +	bool active;
> +	int preset;
>  };
>  
>  /* container for feature view */
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index 4b91d8d9bc37..759c32889efd 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -744,30 +744,20 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
>  }
>  EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
>  
> -/**
> - * cscfg_activate_config -  Mark a configuration descriptor as active.
> - *
> - * This will be seen when csdev devices are enabled in the system.
> - * Only activated configurations can be enabled on individual devices.
> - * Activation protects the configuration from alteration or removal while
> - * active.
> - *
> - * Selection by hash value - generated from the configuration name when it
> - * was loaded and added to the cs_etm/configurations file system for selection
> - * by perf.
> +/*
> + * This activate configuration for either perf or sysfs. Perf can have multiple
> + * active configs, selected per event, sysfs is limited to one.
>   *
>   * Increments the configuration descriptor active count and the global active
>   * count.
>   *
>   * @cfg_hash: Hash value of the selected configuration name.
>   */
> -int cscfg_activate_config(unsigned long cfg_hash)
> +static int _cscfg_activate_config(unsigned long cfg_hash)
>  {
>  	struct cscfg_config_desc *config_desc;
>  	int err = -EINVAL;
>  
> -	mutex_lock(&cscfg_mutex);
> -
>  	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
>  		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
>  			/* must ensure that config cannot be unloaded in use */
> @@ -791,6 +781,101 @@ int cscfg_activate_config(unsigned long cfg_hash)
>  			break;
>  		}
>  	}
> +	return err;
> +}
> +
> +static void _cscfg_deactivate_config(unsigned long cfg_hash)
> +{
> +	struct cscfg_config_desc *config_desc;
> +
> +	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> +		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> +			atomic_dec(&config_desc->active_cnt);
> +			atomic_dec(&cscfg_mgr->sys_active_cnt);
> +			cscfg_owner_put(config_desc->load_owner);
> +			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
> +			break;
> +		}
> +	}
> +}
> +
> +/*
> + * called from configfs to set/clear the active configuration for use when
> + * using sysfs to control trace.
> + */
> +int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool activate)
> +{
> +	unsigned long cfg_hash;
> +	int err = 0;
> +
> +	mutex_lock(&cscfg_mutex);
> +
> +	cfg_hash = (unsigned long)config_desc->event_ea->var;
> +
> +	if (activate) {
> +		/* cannot be a current active value to activate this */
> +		if (cscfg_mgr->sysfs_active_config) {
> +			err = -EBUSY;
> +			goto exit_unlock;
> +		}
> +		err = _cscfg_activate_config(cfg_hash);
> +		if (!err)
> +			cscfg_mgr->sysfs_active_config = cfg_hash;
> +	} else {
> +		/* disable if matching current value */
> +		if (cscfg_mgr->sysfs_active_config == cfg_hash) {
> +			_cscfg_deactivate_config(cfg_hash);
> +			cscfg_mgr->sysfs_active_config = 0;
> +		} else
> +			err = -EINVAL;
> +	}
> +
> +exit_unlock:
> +	mutex_unlock(&cscfg_mutex);
> +	return err;
> +}
> +
> +/* set the sysfs preset value */
> +void cscfg_config_sysfs_set_preset(int preset)
> +{
> +	mutex_lock(&cscfg_mutex);
> +	cscfg_mgr->sysfs_active_preset = preset;
> +	mutex_unlock(&cscfg_mutex);
> +}
> +
> +/*
> + * Used by a device to get the config and preset selected as active in configfs,
> + * when using sysfs to control trace.
> + */
> +void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
> +{
> +	mutex_lock(&cscfg_mutex);
> +	*preset = cscfg_mgr->sysfs_active_preset;
> +	*cfg_hash = cscfg_mgr->sysfs_active_config;
> +	mutex_unlock(&cscfg_mutex);
> +}
> +EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
> +
> +/**
> + * cscfg_activate_config -  Mark a configuration descriptor as active.
> + *
> + * This will be seen when csdev devices are enabled in the system.
> + * Only activated configurations can be enabled on individual devices.
> + * Activation protects the configuration from alteration or removal while
> + * active.
> + *
> + * Selection by hash value - generated from the configuration name when it
> + * was loaded and added to the cs_etm/configurations file system for selection
> + * by perf.
> + *
> + * @cfg_hash: Hash value of the selected configuration name.
> + */
> +int cscfg_activate_config(unsigned long cfg_hash)
> +{
> +	int err = 0;
> +
> +	mutex_lock(&cscfg_mutex);
> +	err = _cscfg_activate_config(cfg_hash);
>  	mutex_unlock(&cscfg_mutex);
>  
>  	return err;
> @@ -806,19 +891,8 @@ EXPORT_SYMBOL_GPL(cscfg_activate_config);
>   */
>  void cscfg_deactivate_config(unsigned long cfg_hash)
>  {
> -	struct cscfg_config_desc *config_desc;
> -
>  	mutex_lock(&cscfg_mutex);
> -
> -	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> -		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> -			atomic_dec(&config_desc->active_cnt);
> -			atomic_dec(&cscfg_mgr->sys_active_cnt);
> -			cscfg_owner_put(config_desc->load_owner);
> -			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
> -			break;
> -		}
> -	}
> +	_cscfg_deactivate_config(cfg_hash);
>  	mutex_unlock(&cscfg_mutex);
>  }
>  EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
> index 1da37874f70f..9106ffab4833 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.h
> @@ -28,6 +28,8 @@
>   * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
>   * @sys_active_cnt:	Total number of active config descriptor references.
>   * @cfgfs_subsys:	configfs subsystem used to manage configurations.
> + * @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
> + * @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
>   */
>  struct cscfg_manager {
>  	struct device dev;
> @@ -37,6 +39,8 @@ struct cscfg_manager {
>  	struct list_head load_order_list;
>  	atomic_t sys_active_cnt;
>  	struct configfs_subsystem cfgfs_subsys;
> +	u32 sysfs_active_config;
> +	int sysfs_active_preset;
>  };
>  
>  /* get reference to dev in cscfg_manager */
> @@ -88,7 +92,8 @@ int cscfg_preload(void *owner_handle);
>  const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
>  int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>  				int param_idx, u64 value);
> -
> +int cscfg_config_sysfs_activate(struct cscfg_config_desc *cfg_desc, bool activate);
> +void cscfg_config_sysfs_set_preset(int preset);
>  
>  /* syscfg manager external API */
>  int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
> @@ -104,5 +109,6 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev);
>  int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
>  				     unsigned long cfg_hash, int preset);
>  void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
> +void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset);
>  
>  #endif /* CORESIGHT_SYSCFG_H */
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 86a313857b58..bf18128cf5de 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -722,7 +722,16 @@  static int etm4_enable_sysfs(struct coresight_device *csdev)
 {
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	struct etm4_enable_arg arg = { };
-	int ret;
+	unsigned long cfg_hash;
+	int ret, preset;
+
+	/* enable any config activated by configfs */
+	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
+	if (cfg_hash) {
+		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
+		if (ret)
+			return ret;
+	}
 
 	spin_lock(&drvdata->spinlock);
 
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
index 345a62f1b728..c388a77a2683 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
@@ -6,6 +6,7 @@ 
 
 #include <linux/configfs.h>
 
+#include "coresight-config.h"
 #include "coresight-syscfg-configfs.h"
 
 /* create a default ci_type. */
@@ -87,9 +88,75 @@  static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page)
 }
 CONFIGFS_ATTR_RO(cscfg_cfg_, values);
 
+static ssize_t cscfg_cfg_activate_show(struct config_item *item, char *page)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+
+	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->active);
+}
+
+static ssize_t cscfg_cfg_activate_store(struct config_item *item,
+					const char *page, size_t count)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+	int err;
+	bool val;
+
+	err = kstrtobool(page, &val);
+	if (!err)
+		err = cscfg_config_sysfs_activate(fs_config->config_desc, val);
+	if (!err) {
+		fs_config->active = val;
+		if (val)
+			cscfg_config_sysfs_set_preset(fs_config->preset);
+	}
+	return err ? err : count;
+}
+CONFIGFS_ATTR(cscfg_cfg_, activate);
+
+static ssize_t cscfg_cfg_active_preset_show(struct config_item *item, char *page)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+
+	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->preset);
+}
+
+static ssize_t cscfg_cfg_active_preset_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+	int preset, err;
+
+	err = kstrtoint(page, 0, &preset);
+	if (!err) {
+		/*
+		 * presets start at 1, and go up to max (15),
+		 * but the config may provide fewer.
+		 */
+		if ((preset < 1) || (preset > fs_config->config_desc->nr_presets))
+			err = -EINVAL;
+	}
+
+	if (!err) {
+		/* set new value */
+		fs_config->preset = preset;
+		/* set on system if active */
+		if (fs_config->active)
+			cscfg_config_sysfs_set_preset(fs_config->preset);
+	}
+	return err ? err : count;
+}
+CONFIGFS_ATTR(cscfg_cfg_, active_preset);
+
 static struct configfs_attribute *cscfg_config_view_attrs[] = {
 	&cscfg_cfg_attr_description,
 	&cscfg_cfg_attr_feature_refs,
+	&cscfg_cfg_attr_activate,
+	&cscfg_cfg_attr_active_preset,
 	NULL,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
index ea1e54d29f7f..373d84d43268 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
@@ -15,6 +15,8 @@ 
 struct cscfg_fs_config {
 	struct cscfg_config_desc *config_desc;
 	struct config_group group;
+	bool active;
+	int preset;
 };
 
 /* container for feature view */
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 4b91d8d9bc37..759c32889efd 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -744,30 +744,20 @@  void cscfg_csdev_reset_feats(struct coresight_device *csdev)
 }
 EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
 
-/**
- * cscfg_activate_config -  Mark a configuration descriptor as active.
- *
- * This will be seen when csdev devices are enabled in the system.
- * Only activated configurations can be enabled on individual devices.
- * Activation protects the configuration from alteration or removal while
- * active.
- *
- * Selection by hash value - generated from the configuration name when it
- * was loaded and added to the cs_etm/configurations file system for selection
- * by perf.
+/*
+ * This activate configuration for either perf or sysfs. Perf can have multiple
+ * active configs, selected per event, sysfs is limited to one.
  *
  * Increments the configuration descriptor active count and the global active
  * count.
  *
  * @cfg_hash: Hash value of the selected configuration name.
  */
-int cscfg_activate_config(unsigned long cfg_hash)
+static int _cscfg_activate_config(unsigned long cfg_hash)
 {
 	struct cscfg_config_desc *config_desc;
 	int err = -EINVAL;
 
-	mutex_lock(&cscfg_mutex);
-
 	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
 		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
 			/* must ensure that config cannot be unloaded in use */
@@ -791,6 +781,101 @@  int cscfg_activate_config(unsigned long cfg_hash)
 			break;
 		}
 	}
+	return err;
+}
+
+static void _cscfg_deactivate_config(unsigned long cfg_hash)
+{
+	struct cscfg_config_desc *config_desc;
+
+	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
+		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
+			atomic_dec(&config_desc->active_cnt);
+			atomic_dec(&cscfg_mgr->sys_active_cnt);
+			cscfg_owner_put(config_desc->load_owner);
+			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
+			break;
+		}
+	}
+}
+
+/*
+ * called from configfs to set/clear the active configuration for use when
+ * using sysfs to control trace.
+ */
+int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool activate)
+{
+	unsigned long cfg_hash;
+	int err = 0;
+
+	mutex_lock(&cscfg_mutex);
+
+	cfg_hash = (unsigned long)config_desc->event_ea->var;
+
+	if (activate) {
+		/* cannot be a current active value to activate this */
+		if (cscfg_mgr->sysfs_active_config) {
+			err = -EBUSY;
+			goto exit_unlock;
+		}
+		err = _cscfg_activate_config(cfg_hash);
+		if (!err)
+			cscfg_mgr->sysfs_active_config = cfg_hash;
+	} else {
+		/* disable if matching current value */
+		if (cscfg_mgr->sysfs_active_config == cfg_hash) {
+			_cscfg_deactivate_config(cfg_hash);
+			cscfg_mgr->sysfs_active_config = 0;
+		} else
+			err = -EINVAL;
+	}
+
+exit_unlock:
+	mutex_unlock(&cscfg_mutex);
+	return err;
+}
+
+/* set the sysfs preset value */
+void cscfg_config_sysfs_set_preset(int preset)
+{
+	mutex_lock(&cscfg_mutex);
+	cscfg_mgr->sysfs_active_preset = preset;
+	mutex_unlock(&cscfg_mutex);
+}
+
+/*
+ * Used by a device to get the config and preset selected as active in configfs,
+ * when using sysfs to control trace.
+ */
+void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
+{
+	mutex_lock(&cscfg_mutex);
+	*preset = cscfg_mgr->sysfs_active_preset;
+	*cfg_hash = cscfg_mgr->sysfs_active_config;
+	mutex_unlock(&cscfg_mutex);
+}
+EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
+
+/**
+ * cscfg_activate_config -  Mark a configuration descriptor as active.
+ *
+ * This will be seen when csdev devices are enabled in the system.
+ * Only activated configurations can be enabled on individual devices.
+ * Activation protects the configuration from alteration or removal while
+ * active.
+ *
+ * Selection by hash value - generated from the configuration name when it
+ * was loaded and added to the cs_etm/configurations file system for selection
+ * by perf.
+ *
+ * @cfg_hash: Hash value of the selected configuration name.
+ */
+int cscfg_activate_config(unsigned long cfg_hash)
+{
+	int err = 0;
+
+	mutex_lock(&cscfg_mutex);
+	err = _cscfg_activate_config(cfg_hash);
 	mutex_unlock(&cscfg_mutex);
 
 	return err;
@@ -806,19 +891,8 @@  EXPORT_SYMBOL_GPL(cscfg_activate_config);
  */
 void cscfg_deactivate_config(unsigned long cfg_hash)
 {
-	struct cscfg_config_desc *config_desc;
-
 	mutex_lock(&cscfg_mutex);
-
-	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
-		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
-			atomic_dec(&config_desc->active_cnt);
-			atomic_dec(&cscfg_mgr->sys_active_cnt);
-			cscfg_owner_put(config_desc->load_owner);
-			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
-			break;
-		}
-	}
+	_cscfg_deactivate_config(cfg_hash);
 	mutex_unlock(&cscfg_mutex);
 }
 EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 1da37874f70f..9106ffab4833 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -28,6 +28,8 @@ 
  * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
  * @sys_active_cnt:	Total number of active config descriptor references.
  * @cfgfs_subsys:	configfs subsystem used to manage configurations.
+ * @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
+ * @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
  */
 struct cscfg_manager {
 	struct device dev;
@@ -37,6 +39,8 @@  struct cscfg_manager {
 	struct list_head load_order_list;
 	atomic_t sys_active_cnt;
 	struct configfs_subsystem cfgfs_subsys;
+	u32 sysfs_active_config;
+	int sysfs_active_preset;
 };
 
 /* get reference to dev in cscfg_manager */
@@ -88,7 +92,8 @@  int cscfg_preload(void *owner_handle);
 const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
 int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 				int param_idx, u64 value);
-
+int cscfg_config_sysfs_activate(struct cscfg_config_desc *cfg_desc, bool activate);
+void cscfg_config_sysfs_set_preset(int preset);
 
 /* syscfg manager external API */
 int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
@@ -104,5 +109,6 @@  void cscfg_csdev_reset_feats(struct coresight_device *csdev);
 int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 				     unsigned long cfg_hash, int preset);
 void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
+void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset);
 
 #endif /* CORESIGHT_SYSCFG_H */