[RFC PATCH 4/8] coresight: configfs: Allow configfs to activate configuration.

[Mike Leach <mike.leach@linaro.org>]

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          |   5 +
 .../coresight/coresight-syscfg-configfs.c     |  67 +++++++++
 .../coresight/coresight-syscfg-configfs.h     |   2 +
 .../hwtracing/coresight/coresight-syscfg.c    | 129 ++++++++++++++----
 .../hwtracing/coresight/coresight-syscfg.h    |   7 +-
 5 files changed, 182 insertions(+), 28 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index b7a4aeaa2bc7..2637096c4621 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -688,6 +688,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
 	struct etm4_enable_arg arg = { };
 	int ret;
 
+	/* enable any config activated by configfs */
+	ret = cscfg_csdev_enable_active_config(csdev, 0, 0);
+	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..ae79ae8b1d7e 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_activation(fs_config->config_desc, val);
+	if (!err) {
+		fs_config->active = val;
+		if (val)
+			cscfg_config_sysfs_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_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 26c1a244c2b1..ab74e33b892b 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -743,32 +743,23 @@ 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 */
 			err = cscfg_owner_get(config_desc->load_owner);
 			if (err)
@@ -790,6 +781,88 @@ 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_activation(struct cscfg_config_desc *config_desc, bool activate)
+{
+	unsigned long cfg_hash_desc;
+	int err = 0;
+
+	mutex_lock(&cscfg_mutex);
+
+	cfg_hash_desc = (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_desc);
+		if (!err)
+			cscfg_mgr->sysfs_active_config = cfg_hash_desc;
+	} else {
+		/* disable if matching current value */
+		if (cscfg_mgr->sysfs_active_config == cfg_hash_desc) {
+			_cscfg_deactivate_config(cfg_hash_desc);
+			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_preset(int preset)
+{
+	mutex_lock(&cscfg_mutex);
+	cscfg_mgr->sysfs_active_preset = preset;
+	mutex_unlock(&cscfg_mutex);
+}
+
+/**
+ * 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;
@@ -805,19 +878,8 @@ 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);
@@ -826,7 +888,8 @@ EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
  * cscfg_csdev_enable_active_config - Enable matching active configuration for device.
  *
  * Enables the configuration selected by @cfg_hash if the configuration is supported
- * on the device and has been activated.
+ * on the device and has been activated. A @cfg_hash value of 0 is used if the device
+ * is being programmed from sysfs, to select the current sysfs active config.
  *
  * If active and supported the CoreSight device @csdev will be programmed with the
  * configuration, using @preset parameters.
@@ -850,6 +913,16 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 		return 0;
 
 	mutex_lock(&cscfg_csdev_mutex);
+
+	/* sysfs controlled coresight will call with cfg_hash == 0 */
+	if (!cfg_hash) {
+		if (!cscfg_mgr->sysfs_active_config)
+			goto exit_unlock;
+
+		cfg_hash = cscfg_mgr->sysfs_active_config;
+		preset = cscfg_mgr->sysfs_active_preset;
+	}
+
 	list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
 		config_desc = config_csdev_item->config_desc;
 		if ((atomic_read(&config_desc->active_cnt)) &&
@@ -863,6 +936,8 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 		if (!err)
 			csdev->active_cscfg_ctxt = (void *)config_csdev_active;
 	}
+
+exit_unlock:
 	mutex_unlock(&cscfg_csdev_mutex);
 	return err;
 }
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 1da37874f70f..e07e1b872806 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_activation(struct cscfg_config_desc *cfg_desc, bool activate);
+void cscfg_config_sysfs_preset(int preset);
 
 /* syscfg manager external API */
 int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
-- 
2.17.1


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