Re: [PATCH v4 09/10] coresight: syscfg: Add initial configfs support

On Sun, Feb 28, 2021 at 05:02:28PM -0700, Mathieu Poirier wrote:

On Thu, Jan 28, 2021 at 05:09:35PM +0000, Mike Leach wrote:

...

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.

Signed-off-by: Mike Leach mike.leach@linaro.org

I get the following warning when applying this patch:

Applying: coresight: syscfg: Add initial configfs support .git/rebase-apply/patch:34: new blank line at EOF. + warning: 1 line adds whitespace errors.

Please address.

...

---

drivers/hwtracing/coresight/Makefile | 3 +- .../hwtracing/coresight/coresight-config.c | 1 + .../coresight/coresight-syscfg-configfs.c | 399 ++++++++++++++++++ .../coresight/coresight-syscfg-configfs.h | 45 ++ .../hwtracing/coresight/coresight-syscfg.c | 77 ++++ .../hwtracing/coresight/coresight-syscfg.h | 7 + 6 files changed, 531 insertions(+), 1 deletion(-) create mode 100644 drivers/hwtracing/coresight/coresight-syscfg-configfs.c create mode 100644 drivers/hwtracing/coresight/coresight-syscfg-configfs.h

diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile index 2707bfef1b76..391c93a08902 100644 --- a/drivers/hwtracing/coresight/Makefile +++ b/drivers/hwtracing/coresight/Makefile @@ -5,7 +5,8 @@ obj-$(CONFIG_CORESIGHT) += coresight.o coresight-y := coresight-core.o coresight-etm-perf.o coresight-platform.o \ coresight-sysfs.o coresight-syscfg.o coresight-config.o \

• coresight-cfg-preload.o coresight-cfg-afdo.o
  

• coresight-cfg-preload.o coresight-cfg-afdo.o \
  

• coresight-syscfg-configfs.o
  

obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \ coresight-tmc-etr.o diff --git a/drivers/hwtracing/coresight/coresight-config.c b/drivers/hwtracing/coresight/coresight-config.c index 6cc4b213d9b6..225ceca1428c 100644 --- a/drivers/hwtracing/coresight/coresight-config.c +++ b/drivers/hwtracing/coresight/coresight-config.c @@ -243,3 +243,4 @@ void cscfg_csdev_disable_config(struct cscfg_config_csdev *cfg) cfg->enabled = false; } }

Spurious change

...

diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c new file mode 100644 index 000000000000..79a11ebd6782 --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright (c) 2020 Linaro Limited, All rights reserved.
• • Author: Mike Leach mike.leach@linaro.org
• */

+#include <linux/configfs.h>

+#include "coresight-syscfg-configfs.h"

+/* create a default ci_type. */ +static inline struct config_item_type *cscfg_create_ci_type(void) +{

• struct config_item_type *ci_type;
• ci_type = devm_kzalloc(to_device_cscfg(), sizeof(*ci_type), GFP_KERNEL);
• if (ci_type)

• ci_type->ct_owner = THIS_MODULE;
  

• return ci_type;

+}

+/* configurations sub-group */

+/* attributes for the config view group */ +static ssize_t cscfg_cfg_description_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, "%s\n", fs_config->desc->brief);

+} +CONFIGFS_ATTR_RO(cscfg_cfg_, description);

+static ssize_t cscfg_cfg_feature_refs_show(struct config_item *item, char *page) +{

• struct cscfg_fs_config *fs_config = container_of(to_config_group(item),

• 					 struct cscfg_fs_config, group);
  

• const struct cscfg_config_desc *desc = fs_config->desc;
• ssize_t ch_used = 0;
• int i;
• if (desc->nr_refs) {

• for (i = 0; i < desc->nr_refs; i++) {
  

• 	ch_used += scnprintf(page + ch_used, PAGE_SIZE - ch_used,
  

• 			     "%s\n", desc->refs[i].name);
  

• }
  

• }
• return ch_used;

+} +CONFIGFS_ATTR_RO(cscfg_cfg_, feature_refs);

+/* list preset values in order of features and params */ +static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page) +{

• const struct cscfg_feature_desc *feat;
• const struct cscfg_config_desc *cfg;
• struct cscfg_fs_preset *fs_preset;
• int i, j, val_idx, preset_idx;
• ssize_t used = 0;
• fs_preset = container_of(to_config_group(item), struct cscfg_fs_preset, group);
• cfg = fs_preset->desc;
• if (!cfg->nr_presets)

• return 0;
  

• preset_idx = fs_preset->preset_num - 1;
• /* start index on the correct array line */
• val_idx = cfg->nr_total_params * preset_idx;
• /*

• * A set of presets is the sum of all params in used features,
  

• * in order of declaration of features and params in the features
  

• */
  

• for (i = 0; i < cfg->nr_refs; i++) {

• feat = cscfg_get_named_feat_desc(cfg->refs[i].name);
  

• for (j = 0; j < feat->nr_params; j++) {
  

• 	used += scnprintf(page + used, PAGE_SIZE - used,
  

• 			  "%s.%s = 0x%llx ",
  

• 			  feat->name, feat->params[j].name,
  

• 			  cfg->presets[val_idx++]);
  

• }
  

• }
• used += scnprintf(page + used, PAGE_SIZE - used, "\n");
• return used;

+} +CONFIGFS_ATTR_RO(cscfg_cfg_, values);

+static struct configfs_attribute *cscfg_config_view_attrs[] = {

• &cscfg_cfg_attr_description,
• &cscfg_cfg_attr_feature_refs,
• NULL,

+};

+static struct config_item_type cscfg_config_view_type = {

• .ct_owner = THIS_MODULE,
• .ct_attrs = cscfg_config_view_attrs,

+};

+static struct configfs_attribute *cscfg_config_preset_attrs[] = {

• &cscfg_cfg_attr_values,
• NULL,

+};

+static struct config_item_type cscfg_config_preset_type = {

• .ct_owner = THIS_MODULE,
• .ct_attrs = cscfg_config_preset_attrs,

+};

Extra line

...

+static int cscfg_add_preset_groups(struct cscfg_fs_config *cfg_view) +{

• int preset_num;
• struct cscfg_fs_preset *cfg_preset;
• struct cscfg_config_desc *cfg_desc = cfg_view->desc;
• char name[CONFIGFS_ITEM_NAME_LEN];
• if (!cfg_desc->nr_presets)

• return 0;
  

• for (preset_num = 1; preset_num <= cfg_desc->nr_presets; preset_num++) {

• cfg_preset = devm_kzalloc(to_device_cscfg(),
  

• 			  sizeof(struct cscfg_fs_config), GFP_KERNEL);
  

• if (!cfg_preset)
  

• 	return -ENOMEM;
  

• snprintf(name, CONFIGFS_ITEM_NAME_LEN, "preset%d", preset_num);
  

• cfg_preset->preset_num = preset_num;
  

• cfg_preset->desc = cfg_view->desc;
  

• config_group_init_type_name(&cfg_preset->group, name,
  

• 			    &cscfg_config_preset_type);
  

• configfs_add_default_group(&cfg_preset->group, &cfg_view->group);
  

• }
• return 0;

+}

+static struct config_group *cscfg_create_config_group(struct cscfg_config_desc *cfg_desc) +{

• struct cscfg_fs_config *cfg_view;
• struct device *dev = to_device_cscfg();
• int err;
• if (!dev)

• return ERR_PTR(-EINVAL);
  

• cfg_view = devm_kzalloc(dev, sizeof(struct cscfg_fs_config), GFP_KERNEL);
• if (!cfg_view)

• return ERR_PTR(-ENOMEM);
  

• cfg_view->desc = cfg_desc;
• config_group_init_type_name(&cfg_view->group, cfg_desc->name, &cscfg_config_view_type);
• /* add in a preset<n> dir for each preset */
• err = cscfg_add_preset_groups(cfg_view);
• if (err)

• return ERR_PTR(err);
  

• return &cfg_view->group;

+}

+/* attributes for features view */

+static ssize_t cscfg_feat_description_show(struct config_item *item, char *page) +{

• struct cscfg_fs_feature *fs_feat = container_of(to_config_group(item),

• 					struct cscfg_fs_feature, group);
  

• return scnprintf(page, PAGE_SIZE, "%s\n", fs_feat->desc->brief);

+} +CONFIGFS_ATTR_RO(cscfg_feat_, description);

+static ssize_t cscfg_feat_matches_show(struct config_item *item, char *page) +{

• struct cscfg_fs_feature *fs_feat = container_of(to_config_group(item),

• 					struct cscfg_fs_feature, group);
  

• u32 match_flags = fs_feat->desc->match_flags;
• int used = 0;
• if (match_flags & CS_CFG_MATCH_CLASS_SRC_ALL)

• used = scnprintf(page, PAGE_SIZE, "SRC_ALL ");
  

• if (match_flags & CS_CFG_MATCH_CLASS_SRC_ETM4)

• used += scnprintf(page + used, PAGE_SIZE - used, "SRC_ETMV4 ");
  

• used += scnprintf(page + used, PAGE_SIZE - used, "\n");
• return used;

+} +CONFIGFS_ATTR_RO(cscfg_feat_, matches);

+static ssize_t cscfg_feat_nr_params_show(struct config_item *item, char *page) +{

• struct cscfg_fs_feature *fs_feat = container_of(to_config_group(item),

• 					struct cscfg_fs_feature, group);
  

• return scnprintf(page, PAGE_SIZE, "%d\n", fs_feat->desc->nr_params);

+} +CONFIGFS_ATTR_RO(cscfg_feat_, nr_params);

+/* base feature desc attrib structures */ +static struct configfs_attribute *cscfg_feature_view_attrs[] = {

• &cscfg_feat_attr_description,
• &cscfg_feat_attr_matches,
• &cscfg_feat_attr_nr_params,
• NULL,

+};

+static struct config_item_type cscfg_feature_view_type = {

• .ct_owner = THIS_MODULE,
• .ct_attrs = cscfg_feature_view_attrs,

+};

+static ssize_t cscfg_param_value_show(struct config_item *item, char *page) +{

• struct cscfg_fs_param *param_item = container_of(to_config_group(item),

• 					 struct cscfg_fs_param, group);
  

• int param_idx = param_item->param_idx;
• struct cscfg_feature_desc *desc = param_item->desc;
• return scnprintf(page, PAGE_SIZE, "0x%llx\n", desc->params[param_idx].value);

+}

+static ssize_t cscfg_param_value_store(struct config_item *item,

• 		       const char *page, size_t size)
  

+{

• struct cscfg_fs_param *param_item = container_of(to_config_group(item),

• 					 struct cscfg_fs_param, group);
  

• struct cscfg_feature_desc *desc = param_item->desc;
• int param_idx = param_item->param_idx;
• u64 val;
• int err;
• err = kstrtoull(page, 0, &val);
• if (!err)

• err = cscfg_update_feat_param_val(desc, param_idx, val);
  

• return err ? err : size;

+} +CONFIGFS_ATTR(cscfg_param_, value);

+static struct configfs_attribute *cscfg_param_view_attrs[] = {

• &cscfg_param_attr_value,
• NULL,

+};

+static struct config_item_type cscfg_param_view_type = {

• .ct_owner = THIS_MODULE,
• .ct_attrs = cscfg_param_view_attrs,

+};

+/*

• • configfs has far less functionality provided to add attributes dynamically than sysfs,
• • and the show and store fns pass the enclosing config_item so the actual attribute cannot
• • be determined. Therefore we add each item as a group directory, with a value attribute.
• */

+static int cscfg_create_params_group_items(struct cscfg_feature_desc *feat_desc,

• 			   struct config_group *params_group)
  

+{

• struct device *dev = to_device_cscfg();
• struct cscfg_fs_param *param_item;
• int i;
• /* parameter items - as groups with default_value attribute */
• for (i = 0; i < feat_desc->nr_params; i++) {

• param_item = devm_kzalloc(dev, sizeof(struct cscfg_fs_param), GFP_KERNEL);
  

• if (!param_item)
  

• 	return -ENOMEM;
  

• param_item->desc = feat_desc;
  

• param_item->param_idx = i;
  

• config_group_init_type_name(&param_item->group, feat_desc->params[i].name,
  

• 			    &cscfg_param_view_type);
  

• configfs_add_default_group(&param_item->group, params_group);
  

• }
• return 0;

+}

+static struct config_group *cscfg_create_feature_group(struct cscfg_feature_desc *feat_desc) +{

• struct cscfg_fs_feature *feat_view;
• struct config_item_type *params_group_type;
• struct config_group *params_group = NULL;
• struct device *dev = to_device_cscfg();
• int item_err;
• if (!dev)

• return ERR_PTR(-EINVAL);
  

• feat_view = devm_kzalloc(dev, sizeof(struct cscfg_fs_feature), GFP_KERNEL);
• if (!feat_view)

• return ERR_PTR(-ENOMEM);
  

• if (feat_desc->nr_params) {

• params_group = devm_kzalloc(dev, sizeof(struct config_group), GFP_KERNEL);
  

• if (!params_group)
  

• 	return ERR_PTR(-ENOMEM);
  

• params_group_type = cscfg_create_ci_type();
  

• if (!params_group_type)
  

• 	return ERR_PTR(-ENOMEM);
  

• }
• feat_view->desc = feat_desc;
• config_group_init_type_name(&feat_view->group,

• 		    feat_desc->name,
  

• 		    &cscfg_feature_view_type);
  

• if (params_group) {

• config_group_init_type_name(params_group, "params", params_group_type);
  

• configfs_add_default_group(params_group, &feat_view->group);
  

• item_err = cscfg_create_params_group_items(feat_desc, params_group);
  

• if (item_err)
  

• 	return ERR_PTR(item_err);
  

• }
• return &feat_view->group;

+}

+static struct config_item_type cscfg_configs_type = {

• .ct_owner = THIS_MODULE,

+};

+static struct config_group cscfg_configs_grp = {

• .cg_item = {

• .ci_namebuf = "configurations",
  

• .ci_type = &cscfg_configs_type,
  

• },

+};

+/* add configuration to configurations group */ +int cscfg_configfs_add_config(struct cscfg_config_desc *cfg_desc) +{

• struct config_group *new_group;
• int err;
• new_group = cscfg_create_config_group(cfg_desc);
• if (IS_ERR(new_group))

• return PTR_ERR(new_group);
  

• err = configfs_register_group(&cscfg_configs_grp, new_group);
• return err;

+}

+static struct config_item_type cscfg_features_type = {

• .ct_owner = THIS_MODULE,

+};

+static struct config_group cscfg_features_grp = {

• .cg_item = {

• .ci_namebuf = "features",
  

• .ci_type = &cscfg_features_type,
  

• },

+};

+/* add feature to features group */ +int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc) +{

• struct config_group *new_group;
• int err;
• new_group = cscfg_create_feature_group(feat_desc);
• if (IS_ERR(new_group))

• return PTR_ERR(new_group);
  

• err = configfs_register_group(&cscfg_features_grp, new_group);
• return err;

+}

+int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr) +{

• struct configfs_subsystem *subsys;
• struct config_item_type *ci_type;
• if (!cscfg_mgr)

• return -EINVAL;
  

• ci_type = cscfg_create_ci_type();
• if (!ci_type)

• return -ENOMEM;
  

• subsys = &cscfg_mgr->cfgfs_subsys;
• config_item_set_name(&subsys->su_group.cg_item, CSCFG_FS_SUBSYS_NAME);
• subsys->su_group.cg_item.ci_type = ci_type;
• config_group_init(&subsys->su_group);
• mutex_init(&subsys->su_mutex);
• /* Add default groups to subsystem */
• config_group_init(&cscfg_configs_grp);
• configfs_add_default_group(&cscfg_configs_grp, &subsys->su_group);
• config_group_init(&cscfg_features_grp);
• configfs_add_default_group(&cscfg_features_grp, &subsys->su_group);
• return configfs_register_subsystem(subsys);

+}

+void cscfg_configfs_release(struct cscfg_manager *cscfg_mgr) +{

• configfs_unregister_subsystem(&cscfg_mgr->cfgfs_subsys);

+} diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h new file mode 100644 index 000000000000..5e49819b80fc --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/*

• • Coresight system configuration driver - support for configfs.
• */

+#ifndef CORESIGHT_SYSCFG_CONFIGFS_H +#define CORESIGHT_SYSCFG_CONFIGFS_H

+#include <linux/configfs.h> +#include "coresight-syscfg.h"

+#define CSCFG_FS_SUBSYS_NAME "coresight-syscfg"

We have cs_etm under /sys/bus/events/device/. Would it make sense to call this cs-syscfg?

...

+/* container for configuration view */ +struct cscfg_fs_config {

• struct cscfg_config_desc *desc;
• struct config_group group;

+};

+/* container for feature view */ +struct cscfg_fs_feature {

• struct cscfg_feature_desc *desc;
• struct config_group group;

+};

+/* container for parameter view */ +struct cscfg_fs_param {

• int param_idx;
• struct cscfg_feature_desc *desc;
• struct config_group group;

+};

+/* container for preset view */ +struct cscfg_fs_preset {

• int preset_num;
• struct cscfg_config_desc *desc;
• struct config_group group;

+};

+int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr); +void cscfg_configfs_release(struct cscfg_manager *cscfg_mgr); +int cscfg_configfs_add_config(struct cscfg_config_desc *cfg_desc); +int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc);

+#endif /* CORESIGHT_SYSCFG_CONFIGFS_H */ diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index d79cf5b36758..c0707c31fc31 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

@@ -302,6 +303,70 @@ static int cscfg_load_config(struct cscfg_config_desc *cfg_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 = NULL, *feat_item;
• mutex_lock(&cscfg_mutex);
• list_for_each_entry(feat_item, &cscfg_mgr->data.feat_desc_list, item) {

• if (strcmp(feat_item->name, name) == 0) {
  

• 	feat = feat_item;
  

• 	break;
  

• }
  

• }
• mutex_unlock(&cscfg_mutex);
• return feat;

+}

+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 = NULL, *item;
• list_for_each_entry(item, &csdev->feature_csdev_list, node) {

• if (item->desc == feat_desc) {
  

• 	feat_csdev = item;
  

• 	break;
  

• }
  

• }
• return feat_csdev;

+}

+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_csdev_register *item;
• mutex_lock(&cscfg_mutex);
• /* check if any config active & return busy */
• if (atomic_read(&cscfg_mgr->data.sys_active_cnt)) {

• err = -EBUSY;
  

• goto unlock_exit;
  

• }
• /* set the value */
• feat_desc->params[param_idx].value = value;
• /* update loaded instances.*/
• list_for_each_entry(item, &cscfg_mgr->data.csdev_desc_list, item) {

• feat_csdev = cscfg_csdev_get_feat_from_desc(item->csdev, feat_desc);
  

• if (feat_csdev)
  

• 	feat_csdev->params[param_idx].current_value = value;
  

• }

+unlock_exit:

• mutex_unlock(&cscfg_mutex);
• return err;

+}

Extra line

...

/*

• External API function to load feature and config sets.
• Take a 0 terminated array of feature descriptors and/or configuration

@@ -324,6 +389,7 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, feat_descs[i]->name); goto do_unlock; }

• 	cscfg_configfs_add_feature(feat_descs[i]);
  i++;
  

  } }

@@ -338,6 +404,7 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, cfg_descs[i]->name); goto do_unlock; }

• 	cscfg_configfs_add_config(cfg_descs[i]);
  i++;
  

  } }

@@ -613,6 +680,7 @@ struct device *to_device_cscfg(void) /* Must have a release function or the kernel will complain on module unload */ void cscfg_dev_release(struct device *dev) {

• cscfg_configfs_release(cscfg_mgr); kfree(cscfg_mgr); cscfg_mgr = NULL;

} @@ -639,6 +707,7 @@ int cscfg_create_device(void) dev->init_name = "system_cfg"; err = device_register(dev);

Extra line

I have run out of time for this patchset. Please spin off another revision and we'll go from there.

The core of the feature works and I think we should move forward with it.

Thanks, Mathieu

...

if (err) cscfg_dev_release(dev); @@ -668,6 +737,10 @@ int __init cscfg_init(void) if (err) return err;

• err = cscfg_configfs_init(cscfg_mgr);
• if (err)

• goto exit_dev_clear;
  

• INIT_LIST_HEAD(&cscfg_mgr->data.csdev_desc_list); INIT_LIST_HEAD(&cscfg_mgr->data.feat_desc_list); INIT_LIST_HEAD(&cscfg_mgr->data.config_desc_list);

@@ -676,6 +749,10 @@ int __init cscfg_init(void) dev_info(to_device_cscfg(), "CoreSight Configuration manager initialised"); return 0;

+exit_dev_clear:

• cscfg_clear_device();
• return err;

} void __exit cscfg_exit(void) diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h index a8a6b21315d8..62700e4e9e05 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.h +++ b/drivers/hwtracing/coresight/coresight-syscfg.h @@ -6,6 +6,7 @@ #ifndef CORESIGHT_SYSCFG_H #define CORESIGHT_SYSCFG_H +#include <linux/configfs.h> #include <linux/coresight.h> #include <linux/device.h> @@ -48,6 +49,10 @@ struct cscfg_csdev_register { int __init cscfg_init(void); void __exit cscfg_exit(void); int cscfg_preload(void); +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);
  

/* syscfg manager external API */ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, @@ -71,10 +76,12 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev);

• @dev: The device.
• @data: The API data.

• • @cfgfs_subsys: configfs subsystem used to manage configurations.
  */

struct cscfg_manager { struct device dev; struct cscfg_api_data data;

• struct configfs_subsystem cfgfs_subsys;

}; /* get reference to dev in cscfg_manager */ -- 2.17.1