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References: <20210316180400.7184-1-mike.leach@linaro.org> <20210316180400.7184-10-mike.leach@linaro.org>
 <20210405205613.GE145043@xps15>
In-Reply-To: <20210405205613.GE145043@xps15>
From:   Mike Leach <mike.leach@linaro.org>
Date:   Tue, 6 Apr 2021 12:08:19 +0100
Message-ID: <CAJ9a7Vj==w=4ai=DCbT=Ssn=xucvbMFCtsWCVEf3FbBgmHdpPw@mail.gmail.com>
Subject: Re: [PATCH v5 09/10] coresight: syscfg: Add initial configfs support
To:     Mathieu Poirier <mathieu.poirier@linaro.org>
Cc:     linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Coresight ML <coresight@lists.linaro.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        "Suzuki K. Poulose" <suzuki.poulose@arm.com>,
        Yabin Cui <yabinc@google.com>,
        Jonathan Corbet <corbet@lwn.net>, Leo Yan <leo.yan@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Tingwei Zhang <tingwei@codeaurora.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Mathieu,

On Mon, 5 Apr 2021 at 21:56, Mathieu Poirier <mathieu.poirier@linaro.org> wrote:
>
> On Tue, Mar 16, 2021 at 06:03:59PM +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>
> > ---
> >  drivers/hwtracing/coresight/Makefile          |   3 +-
> >  .../coresight/coresight-syscfg-configfs.c     | 399 ++++++++++++++++++
> >  .../coresight/coresight-syscfg-configfs.h     |  45 ++
> >  .../hwtracing/coresight/coresight-syscfg.c    |  77 ++++
> >  .../hwtracing/coresight/coresight-syscfg.h    |   7 +
> >  5 files changed, 530 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-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> > new file mode 100644
> > index 000000000000..7cefad81d1f6
> > --- /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(cscfg_device(), 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->config_desc->description);
> > +}
> > +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 *config_desc = fs_config->config_desc;
> > +     ssize_t ch_used = 0;
> > +     int i;
> > +
> > +     if (config_desc->nr_feat_refs) {
>
> This check isn't needed.
>
Agreed.

> > +             for (i = 0; i < config_desc->nr_feat_refs; i++) {
> > +                     ch_used += scnprintf(page + ch_used, PAGE_SIZE - ch_used,
> > +                                          "%s\n", config_desc->feat_ref_names[i]);
> > +             }
> > +     }
> > +     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_desc;
> > +     const struct cscfg_config_desc *config_desc;
> > +     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);
> > +     config_desc = fs_preset->config_desc;
> > +
> > +     if (!config_desc->nr_presets)
> > +             return 0;
> > +
> > +     preset_idx = fs_preset->preset_num - 1;
> > +
> > +     /* start index on the correct array line */
> > +     val_idx = config_desc->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 < config_desc->nr_feat_refs; i++) {
> > +             feat_desc = cscfg_get_named_feat_desc(config_desc->feat_ref_names[i]);
> > +             for (j = 0; j < feat_desc->nr_params; j++) {
> > +                     used += scnprintf(page + used, PAGE_SIZE - used,
> > +                                       "%s.%s = 0x%llx ",
> > +                                       feat_desc->name,
> > +                                       feat_desc->params_desc[j].name,
> > +                                       config_desc->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,
> > +};
> > +
> > +static int cscfg_add_preset_groups(struct cscfg_fs_config *cfg_view)
> > +{
> > +     int preset_num;
> > +     struct cscfg_fs_preset *cfg_fs_preset;
> > +     struct cscfg_config_desc *config_desc = cfg_view->config_desc;
> > +     char name[CONFIGFS_ITEM_NAME_LEN];
> > +
> > +     if (!config_desc->nr_presets)
> > +             return 0;
> > +
> > +     for (preset_num = 1; preset_num <= config_desc->nr_presets; preset_num++) {
> > +             cfg_fs_preset = devm_kzalloc(cscfg_device(),
> > +                                          sizeof(struct cscfg_fs_preset), GFP_KERNEL);
> > +
> > +             if (!cfg_fs_preset)
> > +                     return -ENOMEM;
> > +
> > +             snprintf(name, CONFIGFS_ITEM_NAME_LEN, "preset%d", preset_num);
> > +             cfg_fs_preset->preset_num = preset_num;
> > +             cfg_fs_preset->config_desc = cfg_view->config_desc;
> > +             config_group_init_type_name(&cfg_fs_preset->group, name,
> > +                                         &cscfg_config_preset_type);
> > +             configfs_add_default_group(&cfg_fs_preset->group, &cfg_view->group);
> > +     }
> > +     return 0;
> > +}
> > +
> > +static struct config_group *cscfg_create_config_group(struct cscfg_config_desc *config_desc)
> > +{
> > +     struct cscfg_fs_config *cfg_view;
> > +     struct device *dev = cscfg_device();
> > +     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->config_desc = config_desc;
> > +     config_group_init_type_name(&cfg_view->group, config_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->feat_desc->description);
>
> Either remove the '\n' at the end of fs_feat->feat_desc->description or above,
> with a preference toward the former.  The same thing should be done for
> cscfg_cfg_description_show().
>
> Otherwise it creates and exta new line when quering from the command line and it
> is only a matter of time before the automated tools point it out.
>

Will remove here - we cannot control what users are going to put in
their own descriptions. Moreover - it seems that multi-line is
permissible in configfs - see descriptions in the sample code in
./samples/configfs.


> > +}
> > +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->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->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);
> > +     u64 value = param_item->feat_desc->params_desc[param_item->param_idx].value;
> > +
> > +     return scnprintf(page, PAGE_SIZE, "0x%llx\n", 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 *feat_desc = param_item->feat_desc;
> > +     int param_idx = param_item->param_idx;
> > +     u64 value;
> > +     int err;
> > +
> > +     err = kstrtoull(page, 0, &value);
> > +     if (!err)
> > +             err = cscfg_update_feat_param_val(feat_desc, param_idx, value);
> > +
> > +     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 = cscfg_device();
> > +     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->feat_desc = feat_desc;
> > +             param_item->param_idx = i;
> > +             config_group_init_type_name(&param_item->group,
> > +                                         feat_desc->params_desc[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 = cscfg_device();
> > +     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->feat_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 *config_desc)
> > +{
> > +     struct config_group *new_group;
> > +     int err;
> > +
> > +     new_group = cscfg_create_config_group(config_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..7d6ffe35ca4c
> > --- /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 "cs-syscfg"
> > +
> > +/* container for configuration view */
> > +struct cscfg_fs_config {
> > +     struct cscfg_config_desc *config_desc;
> > +     struct config_group group;
> > +};
> > +
> > +/* container for feature view */
> > +struct cscfg_fs_feature {
> > +     struct cscfg_feature_desc *feat_desc;
> > +     struct config_group group;
> > +};
> > +
> > +/* container for parameter view */
> > +struct cscfg_fs_param {
> > +     int param_idx;
> > +     struct cscfg_feature_desc *feat_desc;
> > +     struct config_group group;
> > +};
> > +
> > +/* container for preset view */
> > +struct cscfg_fs_preset {
> > +     int preset_num;
> > +     struct cscfg_config_desc *config_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 *config_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 befc379b85b9..3be3828a40a7 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
> > @@ -288,6 +289,72 @@ 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;
> > +}
> > +
> >  /*
> >   * External API function to load feature and config sets.
> >   * Take a 0 terminated array of feature descriptors and/or configuration
> > @@ -305,6 +372,8 @@ 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);
> > @@ -319,6 +388,8 @@ 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);
> > @@ -608,6 +679,7 @@ int cscfg_create_device(void)
> >       dev->init_name = "cs_system_cfg";
> >
> >       err = device_register(dev);
> > +
>
> Spurious change
>
> I am done reviewing your work.  Before sending another revision please
> ensure everything works properly when applied on top of the ETE/TRBE patchset[1].
> It applies correctly but I'm not sure it does the right thing, especially in
> etm_setup_aux() with the per CPU handle changes that have been introduced.
>

I didn't spot anything that would conflict between the two sets when
reviewing ETE/TRBE a couple of weeks ago - but will check & test
against the suggested branch prior to releasing a v6.

Thanks for the reviews.

Mike


> Thanks,
> Mathieu
>
> [1]. https://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git/log/?h=next-ETE-TRBE
>
>
> >       if (err)
> >               cscfg_dev_release(dev);
> >
> > @@ -624,6 +696,7 @@ 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);
> >  }
> > @@ -637,6 +710,10 @@ 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);
> > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
> > index 7bb8c8e497ba..8d018efd6ead 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>
> >
> > @@ -25,6 +26,7 @@
> >   * @feat_desc_list:  List of feature descriptors to load into registered devices.
> >   * @config_desc_list:        List of system configuration descriptors to load into registered devices.
> >   * @sys_active_cnt:  Total number of active config descriptor references.
> > + * @cfgfs_subsys:    configfs subsystem used to manage configurations.
> >   */
> >  struct cscfg_manager {
> >       struct device dev;
> > @@ -32,6 +34,7 @@ struct cscfg_manager {
> >       struct list_head feat_desc_list;
> >       struct list_head config_desc_list;
> >       atomic_t sys_active_cnt;
> > +     struct configfs_subsystem cfgfs_subsys;
> >  };
> >
> >  /* get reference to dev in cscfg_manager */
> > @@ -57,6 +60,10 @@ struct cscfg_registered_csdev {
> >  int __init cscfg_init(void);
> >  void 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,
> > --
> > 2.17.1
> >


-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK