coresight: configfs: Allow configfs to activate configuration

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>
Link: https://lore.kernel.org/r/20211124200038.28662-6-mike.leach@linaro.org
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

1 files changed, 100 insertions, 26 deletions

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 678ee8250d85..098fc34c4829 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -745,30 +745,20 @@ unlock_exit:
 }
 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 */
@@ -792,6 +782,101 @@ 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;
@@ -807,19 +892,8 @@ 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);