Hi Suzuki,
On Thu, 4 Mar 2021 at 16:49, Suzuki K Poulose suzuki.poulose@arm.com wrote:
On 1/28/21 5:09 PM, Mike Leach wrote:
Configurations are first activated, then when any coresight device is enabled, the active configurations are checked and any matching one is enabled.
This patch provides the activation / enable API.
Signed-off-by: Mike Leach mike.leach@linaro.org
.../hwtracing/coresight/coresight-config.h | 2 + .../hwtracing/coresight/coresight-syscfg.c | 127 ++++++++++++++++++ .../hwtracing/coresight/coresight-syscfg.h | 10 +- include/linux/coresight.h | 2 + 4 files changed, 140 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h index 98380b496046..26396b70c826 100644 --- a/drivers/hwtracing/coresight/coresight-config.h +++ b/drivers/hwtracing/coresight/coresight-config.h @@ -156,6 +156,7 @@ struct cscfg_config_feat_ref {
- @presets: Array of preset values.
- @id_ea: Extended attribute for perf configid value
- @event_ea: Extended attribute for perf event value
*/ struct cscfg_config_desc { const char *name;
- @active_cnt: ref count for activate on this configuration.
@@ -168,6 +169,7 @@ struct cscfg_config_desc { const u64 *presets; /* nr_presets * nr_total_params */ struct dev_ext_attribute *id_ea; struct dev_ext_attribute *event_ea;
atomic_t active_cnt;
};
/**
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index a070f135eca3..d79cf5b36758 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -298,6 +298,7 @@ static int cscfg_load_config(struct cscfg_config_desc *cfg_desc) return err;
list_add(&cfg_desc->item, &cscfg_mgr->data.config_desc_list);
}atomic_set(&cfg_desc->active_cnt, 0); return 0;
@@ -477,6 +478,131 @@ void cscfg_unregister_csdev(struct coresight_device *csdev) } EXPORT_SYMBOL_GPL(cscfg_unregister_csdev);
+void cscfg_csdev_reset_feats(struct coresight_device *csdev) +{
struct cscfg_feature_csdev *feat;
mutex_lock(&cscfg_csdev_mutex);
if (list_empty(&csdev->feature_csdev_list))
goto unlock_exit;
list_for_each_entry(feat, &csdev->feature_csdev_list, node)
cscfg_reset_feat(feat);
+unlock_exit:
mutex_unlock(&cscfg_csdev_mutex);
+} +EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
+/**
- Mark a config descriptor as active.
- This will be seen when csdev devices are activated in the system.
- 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) +{
struct cscfg_config_desc *curr_item, *match_item = 0;
nit: s/0/NULL
OK.
mutex_lock(&cscfg_mutex);
list_for_each_entry(curr_item, &cscfg_mgr->data.config_desc_list, item) {
if ((unsigned long)curr_item->id_ea->var == cfg_hash) {
match_item = curr_item;
atomic_inc(&cscfg_mgr->data.sys_active_cnt);
break;
}
}
mutex_unlock(&cscfg_mutex);
if (!match_item)
return -EINVAL;
dev_dbg(to_device_cscfg(), "Activate config %s.\n", match_item->name);
/* mark the descriptors as active so enable config will use them */
mutex_lock(&cscfg_csdev_mutex);
atomic_inc(&match_item->active_cnt);
mutex_unlock(&cscfg_csdev_mutex);
Is there a guarantee that this item is active and present in the list after we dropped the mutex above ? We could certainly nest the mutex as long as we follow the order everywhere to prevent such a race.
Although removal not supported in this set, the rule is that nothing can be removed while any configuration is active (count on sys_active_cnt). - but a comment here could be added. That said, given this is an atomic, not sure that the mutex is necessary (I think previous versions did more than just update the count), & perhaps the increment should be moved to the main list_for_each loop.
return 0;
+} +EXPORT_SYMBOL_GPL(cscfg_activate_config);
+void cscfg_deactivate_config(unsigned long cfg_hash) +{
struct cscfg_config_desc *curr_item, *match_item = 0;
mutex_lock(&cscfg_mutex);
list_for_each_entry(curr_item, &cscfg_mgr->data.config_desc_list, item) {
if ((unsigned long)curr_item->id_ea->var == cfg_hash) {
match_item = curr_item;
break;
}
}
mutex_unlock(&cscfg_mutex);
if (!match_item)
return;
dev_dbg(to_device_cscfg(), "Deactivate config %s.\n", match_item->name);
mutex_lock(&cscfg_csdev_mutex);
atomic_dec(&match_item->active_cnt);
mutex_unlock(&cscfg_csdev_mutex);
atomic_dec(&cscfg_mgr->data.sys_active_cnt);
+} +EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
+/* Find and program any active config for the supplied device.*/ +int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
unsigned long id_hash, int preset)
+{
struct cscfg_config_csdev *cfg = NULL, *item;
const struct cscfg_config_desc *desc;
int err = 0;
/* quickly check global count */
if (!atomic_read(&cscfg_mgr->data.sys_active_cnt))
return 0;
mutex_lock(&cscfg_csdev_mutex);
list_for_each_entry(item, &csdev->config_csdev_list, node) {
desc = item->desc;
if ((atomic_read(&desc->active_cnt)) &&
((unsigned long)desc->id_ea->var == id_hash)) {
cfg = item;
break;
}
}
if (cfg) {
err = cscfg_csdev_enable_config(cfg, preset);
if (!err)
csdev->active_cfg_ctxt = (void *)cfg;
}
mutex_unlock(&cscfg_csdev_mutex);
return err;
+} +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
+/* save and disable the active config for the device */ +void cscfg_csdev_disable_active_config(struct coresight_device *csdev) +{
struct cscfg_config_csdev *cfg;
mutex_lock(&cscfg_csdev_mutex);
cfg = (struct cscfg_config_csdev *)csdev->active_cfg_ctxt;
if (cfg)
cscfg_csdev_disable_config(cfg);
mutex_unlock(&cscfg_csdev_mutex);
+} +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config);
/* Initialise system configuration management device. */
struct device *to_device_cscfg(void)
@@ -546,6 +672,7 @@ int __init cscfg_init(void) INIT_LIST_HEAD(&cscfg_mgr->data.feat_desc_list); INIT_LIST_HEAD(&cscfg_mgr->data.config_desc_list); cscfg_mgr->data.nr_csdev = 0;
atomic_set(&cscfg_mgr->data.sys_active_cnt, 0); dev_info(to_device_cscfg(), "CoreSight Configuration manager initialised"); return 0;
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h index ebf5e1491d86..301e26e1e98f 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.h +++ b/drivers/hwtracing/coresight/coresight-syscfg.h @@ -17,13 +17,15 @@
- @csdev_list: List of coresight devices registered with the configuration manager.
- @feat_desc_list: List of feature descriptors to load into registered devices.
nit: Is this aligned ? (It is from Patch 1, though).
- @config_desc_list: List of system configuration descriptors to load into registered devices.
- @nr_csdev: Number of registered devices with the cscfg system
- @nr_csdev: Number of registered devices with the cscfg system
Spurious change ?
This struct disappears in the v5 respin, so the comments will too.
- @sys_active_cnt: Total number of active config descriptor references.
*/ struct cscfg_api_data { struct list_head csdev_desc_list; struct list_head feat_desc_list; struct list_head config_desc_list; int nr_csdev;
atomic_t sys_active_cnt;
};
/**
@@ -53,6 +55,12 @@ int cscfg_register_csdev(struct coresight_device *csdev, struct cscfg_match_desc *info, struct cscfg_csdev_feat_ops *ops); void cscfg_unregister_csdev(struct coresight_device *csdev); +int cscfg_activate_config(unsigned long cfg_hash); +void cscfg_deactivate_config(unsigned long cfg_hash); +void cscfg_csdev_reset_feats(struct coresight_device *csdev); +int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
unsigned long id_hash, int preset);
+void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
/**
- System configuration manager device.
diff --git a/include/linux/coresight.h b/include/linux/coresight.h index d0126ed326a6..3941854e8280 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -221,6 +221,7 @@ struct coresight_sysfs_link {
- @has_conns_grp: Have added a "connections" group for sysfs links.
- @feature_csdev_list: List of complex feature programming added to the device.
- @config_csdev_list: List of system configurations added to the device.
*/ struct coresight_device { struct coresight_platform_data *pdata;
- @active_cfg_ctxt: Context information for current active congfig.
@@ -245,6 +246,7 @@ struct coresight_device { /* system configuration and feature lists */ struct list_head feature_csdev_list; struct list_head config_csdev_list;
};void *active_cfg_ctxt;
Suzuki
Thanks for the review.
Mike