coresight: syscfg: Add API to activate and enable configurations

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.

Link: https://lore.kernel.org/r/20210723165444.1048-6-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/20210818194022.379573-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index b93f2b4a777e..795dba576fea 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 +469,219 @@ 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 configuration - set the active configuration
+	 * context 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->active_cscfg_ctxt = (void *)config_csdev_active;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+
+	/*
+	 * If found, attempt to enable
+	 */
+	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. Check the active_cscfg_ctxt
+			 * pointer to ensure no pre-emption disabled it via
+			 * cscfg_csdev_disable_active_config() before
+			 * we could start.
+			 *
+			 * Set enabled if OK, err if not.
+			 */
+			spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+			if (csdev->active_cscfg_ctxt)
+				config_csdev_active->enabled = true;
+			else
+				err = -EBUSY;
+			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;
+
+	/*
+	 * Check if we have an active config, and that it was successfully enabled.
+	 * If it was not enabled, we have no work to do, otherwise mark as disabled.
+	 * Clear the active config pointer.
+	 */
+	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
+	if (config_csdev) {
+		if (!config_csdev->enabled)
+			config_csdev = NULL;
+		else
+			config_csdev->enabled = false;
+	}
+	csdev->active_cscfg_ctxt = NULL;
+	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+
+	/* true if there was an enabled active config */
+	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 +750,7 @@ 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;