On Wed, Jul 07, 2021 at 02:29:58PM +0100, 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 Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org
.../hwtracing/coresight/coresight-config.h | 2 + .../hwtracing/coresight/coresight-syscfg.c | 197 ++++++++++++++++++ .../hwtracing/coresight/coresight-syscfg.h | 8 + include/linux/coresight.h | 4 + 4 files changed, 211 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h index 0667581822c1..25eb6c632692 100644 --- a/drivers/hwtracing/coresight/coresight-config.h +++ b/drivers/hwtracing/coresight/coresight-config.h @@ -127,6 +127,7 @@ struct cscfg_feature_desc {
- @nr_total_params: Sum of all parameters declared by used features
- @presets: Array of preset values.
- @event_ea: Extended attribute for perf event value
*/
- @active_cnt: ref count for activate on this configuration.
struct cscfg_config_desc { @@ -139,6 +140,7 @@ struct cscfg_config_desc { int nr_total_params; const u64 *presets; /* nr_presets * nr_total_params */ 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 b93f2b4a777e..4e9804875a9b 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -282,6 +282,7 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc) return err; list_add(&config_desc->item, &cscfg_mgr->config_desc_list);
- atomic_set(&config_desc->active_cnt, 0); return 0;
} @@ -468,6 +469,201 @@ void cscfg_unregister_csdev(struct coresight_device *csdev) } EXPORT_SYMBOL_GPL(cscfg_unregister_csdev); +/**
- cscfg_csdev_reset_feats - reset features for a CoreSight device.
- Resets all parameters and register values for any features loaded
- into @csdev to their default values.
- @csdev: The CoreSight device.
- */
+void cscfg_csdev_reset_feats(struct coresight_device *csdev) +{
- struct cscfg_feature_csdev *feat_csdev;
- unsigned long flags;
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- if (list_empty(&csdev->feature_csdev_list))
goto unlock_exit;
- list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node)
cscfg_reset_feat(feat_csdev);
+unlock_exit:
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+} +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.
- 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) +{
- 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) {
/*
* increment the global active count - control changes to
* active configurations
*/
atomic_inc(&cscfg_mgr->sys_active_cnt);
/*
* mark the descriptor as active so enable config on a
* device instance will use it
*/
atomic_inc(&config_desc->active_cnt);
err = 0;
dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name);
break;
}
- }
- mutex_unlock(&cscfg_mutex);
- return err;
+} +EXPORT_SYMBOL_GPL(cscfg_activate_config);
+/**
- cscfg_deactivate_config - Mark a config descriptor as inactive.
- Decrement the configuration and global active counts.
- @cfg_hash: Hash value of the selected configuration name.
- */
+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);
dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
break;
}
- }
- mutex_unlock(&cscfg_mutex);
+} +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.
- If active and supported the CoreSight device @csdev will be programmed with the
- configuration, using @preset parameters.
- Should be called before driver hardware enable for the requested device, prior to
- programming and enabling the physical hardware.
- @csdev: CoreSight device to program.
- @cfg_hash: Selector for the configuration.
- @preset: Preset parameter values to use, 0 for current / default values.
- */
+int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
unsigned long cfg_hash, int preset)
+{
- struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item;
- const struct cscfg_config_desc *config_desc;
- unsigned long flags;
- int err = 0;
- /* quickly check global count */
- if (!atomic_read(&cscfg_mgr->sys_active_cnt))
return 0;
- /* look for matching config - set in_enable flag if found */
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- 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)) &&
((unsigned long)config_desc->event_ea->var == cfg_hash)) {
config_csdev_active = config_csdev_item;
csdev->cscfg_in_enable = true;
break;
}
- }
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags)
In the previous revision the mutex wasn't dropped and cscfg_csdev_enable_config() was called with the mutex held. Any reason for not doing that with the spinlock implemenation? If anything it should be more efficient because the spinlock is on a per csdev basis. It would also keep things simple and avoid adding a new ->cscfg_in_enable field to the coresight_device structure. That last point really concerns me - if holding the spinlock is not possible than a new approach should be considered.
Thanks, Mathieu
- /*
* If found, attempt to enable and then set as enabled if no error
* and in enable flag still set.
*/
- if (config_csdev_active) {
/*
* Call the generic routine that will program up the internal
* driver structures prior to programming up the hardware.
* This routine takes the driver spinlock saved in the configs.
*/
err = cscfg_csdev_enable_config(config_csdev_active, preset);
if (!err) {
/*
* Successful programming. re-check in_enable flag
* to avoid potential race with disable config.
*/
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
if (csdev->cscfg_in_enable)
csdev->active_cscfg_ctxt = (void *)config_csdev_active;
csdev->cscfg_in_enable = false;
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
}
- }
- return err;
+} +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
+/**
- cscfg_csdev_disable_active_config - disable an active config on the device.
- Disables the active configuration on the CoreSight device @csdev.
- Disable will save the values of any registers marked in the configurations
- as save on disable.
- Should be called after driver hardware disable for the requested device,
- after disabling the physical hardware and reading back registers.
- @csdev: The CoreSight device.
- */
+void cscfg_csdev_disable_active_config(struct coresight_device *csdev) +{
- struct cscfg_config_csdev *config_csdev;
- unsigned long flags;
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- csdev->cscfg_in_enable = false;
- config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
- csdev->active_cscfg_ctxt = NULL;
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
- if (config_csdev)
cscfg_csdev_disable_config(config_csdev);
+} +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config);
/* Initialise system configuration management device. */ struct device *cscfg_device(void) @@ -536,6 +732,7 @@ int __init cscfg_init(void) INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list); INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list); INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
- atomic_set(&cscfg_mgr->sys_active_cnt, 0);
dev_info(cscfg_device(), "CoreSight Configuration manager initialised"); return 0; diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h index 5bcae3b374c6..a52775890670 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.h +++ b/drivers/hwtracing/coresight/coresight-syscfg.h @@ -24,12 +24,14 @@
- @csdev_desc_list: List of coresight devices registered with the configuration manager.
- @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.
struct cscfg_manager { struct device dev; struct list_head csdev_desc_list; struct list_head feat_desc_list; struct list_head config_desc_list;
- atomic_t sys_active_cnt;
}; /* get reference to dev in cscfg_manager */ @@ -61,5 +63,11 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs, int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags, 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 cfg_hash, int preset);
+void cscfg_csdev_disable_active_config(struct coresight_device *csdev); #endif /* CORESIGHT_SYSCFG_H */ diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 16544ae2b532..e66e1a5fd803 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -223,6 +223,8 @@ struct coresight_sysfs_link {
- @feature_csdev_list: List of complex feature programming added to the device.
- @config_csdev_list: List of system configurations added to the device.
- @cscfg_csdev_lock: Protect the lists of configurations and features.
- @active_cscfg_ctxt: Context information for current active system configuration.
*/
- @cscfg_in_enable: Flag to indicate we are in the process of enabling.
struct coresight_device { struct coresight_platform_data *pdata; @@ -248,6 +250,8 @@ struct coresight_device { struct list_head feature_csdev_list; struct list_head config_csdev_list; spinlock_t cscfg_csdev_lock;
- void *active_cscfg_ctxt;
- bool cscfg_in_enable;
}; /* -- 2.17.1