coresight: syscfg: Add initial configfs support

Adds configfs subsystem and attributes to the configuration manager
to enable the listing of loaded configurations and features.

The default values of feature parameters can be accessed and altered
from these attributes to affect all installed devices using the feature.

Link: https://lore.kernel.org/r/20210723165444.1048-10-mike.leach@linaro.org
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210818194022.379573-10-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index c0f764d85f20..fc0760f55c53 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -9,6 +9,7 @@
 #include "coresight-config.h"
 #include "coresight-etm-perf.h"
 #include "coresight-syscfg.h"
+#include "coresight-syscfg-configfs.h"
 
 /*
  * cscfg_ API manages configurations and features for the entire coresight
@@ -286,6 +287,72 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc)
 	return 0;
 }
 
+/* get a feature descriptor by name */
+const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name)
+{
+	const struct cscfg_feature_desc *feat_desc = NULL, *feat_desc_item;
+
+	mutex_lock(&cscfg_mutex);
+
+	list_for_each_entry(feat_desc_item, &cscfg_mgr->feat_desc_list, item) {
+		if (strcmp(feat_desc_item->name, name) == 0) {
+			feat_desc = feat_desc_item;
+			break;
+		}
+	}
+
+	mutex_unlock(&cscfg_mutex);
+	return feat_desc;
+}
+
+/* called with cscfg_mutex held */
+static struct cscfg_feature_csdev *
+cscfg_csdev_get_feat_from_desc(struct coresight_device *csdev,
+			       struct cscfg_feature_desc *feat_desc)
+{
+	struct cscfg_feature_csdev *feat_csdev;
+
+	list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) {
+		if (feat_csdev->feat_desc == feat_desc)
+			return feat_csdev;
+	}
+	return NULL;
+}
+
+int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
+				int param_idx, u64 value)
+{
+	int err = 0;
+	struct cscfg_feature_csdev *feat_csdev;
+	struct cscfg_registered_csdev *csdev_item;
+
+	mutex_lock(&cscfg_mutex);
+
+	/* check if any config active & return busy */
+	if (atomic_read(&cscfg_mgr->sys_active_cnt)) {
+		err = -EBUSY;
+		goto unlock_exit;
+	}
+
+	/* set the value */
+	if ((param_idx < 0) || (param_idx >= feat_desc->nr_params)) {
+		err = -EINVAL;
+		goto unlock_exit;
+	}
+	feat_desc->params_desc[param_idx].value = value;
+
+	/* update loaded instances.*/
+	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
+		feat_csdev = cscfg_csdev_get_feat_from_desc(csdev_item->csdev, feat_desc);
+		if (feat_csdev)
+			feat_csdev->params_csdev[param_idx].current_value = value;
+	}
+
+unlock_exit:
+	mutex_unlock(&cscfg_mutex);
+	return err;
+}
+
 /**
  * cscfg_load_config_sets - API function to load feature and config sets.
  *
@@ -307,6 +374,8 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 	if (feat_descs) {
 		while (feat_descs[i]) {
 			err = cscfg_load_feat(feat_descs[i]);
+			if (!err)
+				err = cscfg_configfs_add_feature(feat_descs[i]);
 			if (err) {
 				pr_err("coresight-syscfg: Failed to load feature %s\n",
 				       feat_descs[i]->name);
@@ -321,6 +390,8 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 	if (config_descs) {
 		while (config_descs[i]) {
 			err = cscfg_load_config(config_descs[i]);
+			if (!err)
+				err = cscfg_configfs_add_config(config_descs[i]);
 			if (err) {
 				pr_err("coresight-syscfg: Failed to load configuration %s\n",
 				       config_descs[i]->name);
@@ -734,6 +805,7 @@ static void cscfg_clear_device(void)
 	list_for_each_entry(cfg_desc, &cscfg_mgr->config_desc_list, item) {
 		etm_perf_del_symlink_cscfg(cfg_desc);
 	}
+	cscfg_configfs_release(cscfg_mgr);
 	device_unregister(cscfg_device());
 	mutex_unlock(&cscfg_mutex);
 }
@@ -747,6 +819,10 @@ int __init cscfg_init(void)
 	if (err)
 		return err;
 
+	err = cscfg_configfs_init(cscfg_mgr);
+	if (err)
+		goto exit_err;
+
 	INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
 	INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
 	INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);