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From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 02/11] coresight: syscfg: Add registration and feature loading for cs devices
Date:   Wed, 18 Aug 2021 13:40:13 -0600
Message-Id: <20210818194022.379573-3-mathieu.poirier@linaro.org>
In-Reply-To: <20210818194022.379573-1-mathieu.poirier@linaro.org>
References: <20210818194022.379573-1-mathieu.poirier@linaro.org>
MIME-Version: 1.0
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From: Mike Leach <mike.leach@linaro.org>

API for individual devices to register with the syscfg management
system is added.

Devices register with matching information, and any features or
configurations that match will be loaded into the device.

The feature and configuration loading is extended so that on load these
are loaded into any currently registered devices. This allows
configuration loading after devices have been registered.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20210723165444.1048-3-mike.leach@linaro.org
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../hwtracing/coresight/coresight-config.h    |  98 +++++
 .../hwtracing/coresight/coresight-syscfg.c    | 338 +++++++++++++++++-
 .../hwtracing/coresight/coresight-syscfg.h    |  19 +
 include/linux/coresight.h                     |   7 +
 4 files changed, 461 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
index 21aa7464dcdc..685fb46ce893 100644
--- a/drivers/hwtracing/coresight/coresight-config.h
+++ b/drivers/hwtracing/coresight/coresight-config.h
@@ -139,4 +139,102 @@ struct cscfg_config_desc {
 	const u64 *presets; /* nr_presets * nr_total_params */
 };
 
+/**
+ * config register instance - part of a loaded feature.
+ *                            maps register values to csdev driver structures
+ *
+ * @reg_desc:		value to use when setting feature on device / store for
+ *			readback of volatile values.
+ * @driver_regval:	pointer to internal driver element used to set the value
+ *			in hardware.
+ */
+struct cscfg_regval_csdev {
+	struct cscfg_regval_desc reg_desc;
+	void *driver_regval;
+};
+
+/**
+ * config parameter instance - part of a loaded feature.
+ *
+ * @feat_csdev:		parent feature
+ * @reg_csdev:		register value updated by this parameter.
+ * @current_value:	current value of parameter - may be set by user via
+ *			sysfs, or modified during device operation.
+ * @val64:		true if 64 bit value
+ */
+struct cscfg_parameter_csdev {
+	struct cscfg_feature_csdev *feat_csdev;
+	struct cscfg_regval_csdev *reg_csdev;
+	u64 current_value;
+	bool val64;
+};
+
+/**
+ * Feature instance loaded into a CoreSight device.
+ *
+ * When a feature is loaded into a specific device, then this structure holds
+ * the connections between the register / parameter values used and the
+ * internal data structures that are written when the feature is enabled.
+ *
+ * Since applying a feature modifies internal data structures in the device,
+ * then we have a reference to the device spinlock to protect access to these
+ * structures (@drv_spinlock).
+ *
+ * @feat_desc:		pointer to the static descriptor for this feature.
+ * @csdev:		parent CoreSight device instance.
+ * @node:		list entry into feature list for this device.
+ * @drv_spinlock:	device spinlock for access to driver register data.
+ * @nr_params:		number of parameters.
+ * @params_csdev:	current parameter values on this device
+ * @nr_regs:		number of registers to be programmed.
+ * @regs_csdev:		Programming details for the registers
+ */
+struct cscfg_feature_csdev {
+	const struct cscfg_feature_desc *feat_desc;
+	struct coresight_device *csdev;
+	struct list_head node;
+	spinlock_t *drv_spinlock;
+	int nr_params;
+	struct cscfg_parameter_csdev *params_csdev;
+	int nr_regs;
+	struct cscfg_regval_csdev *regs_csdev;
+};
+
+/**
+ * Configuration instance when loaded into a CoreSight device.
+ *
+ * The instance contains references to loaded features on this device that are
+ * used by the configuration.
+ *
+ * @config_desc:reference to the descriptor for this configuration
+ * @csdev:	parent coresight device for this configuration instance.
+ * @enabled:	true if configuration is enabled on this device.
+ * @node:	list entry within the coresight device
+ * @nr_feat:	Number of features on this device that are used in the
+ *		configuration.
+ * @feats_csdev:references to the device features to enable.
+ */
+struct cscfg_config_csdev {
+	const struct cscfg_config_desc *config_desc;
+	struct coresight_device *csdev;
+	bool enabled;
+	struct list_head node;
+	int nr_feat;
+	struct cscfg_feature_csdev *feats_csdev[0];
+};
+
+/**
+ * Coresight device operations.
+ *
+ * Registered coresight devices provide these operations to manage feature
+ * instances compatible with the device hardware and drivers
+ *
+ * @load_feat:	Pass a feature descriptor into the device and create the
+ *		loaded feature instance (struct cscfg_feature_csdev).
+ */
+struct cscfg_csdev_feat_ops {
+	int (*load_feat)(struct coresight_device *csdev,
+			 struct cscfg_feature_csdev *feat_csdev);
+};
+
 #endif /* _CORESIGHT_CORESIGHT_CONFIG_H */
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 417db3f92c2f..2c0d4906e226 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -25,6 +25,198 @@ static struct cscfg_manager *cscfg_mgr;
 
 /* load features and configuations into the lists */
 
+/* get name feature instance from a coresight device list of features */
+static struct cscfg_feature_csdev *
+cscfg_get_feat_csdev(struct coresight_device *csdev, const char *name)
+{
+	struct cscfg_feature_csdev *feat_csdev = NULL;
+
+	list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) {
+		if (strcmp(feat_csdev->feat_desc->name, name) == 0)
+			return feat_csdev;
+	}
+	return NULL;
+}
+
+/* allocate the device config instance - with max number of used features */
+static struct cscfg_config_csdev *
+cscfg_alloc_csdev_cfg(struct coresight_device *csdev, int nr_feats)
+{
+	struct cscfg_config_csdev *config_csdev = NULL;
+	struct device *dev = csdev->dev.parent;
+
+	/* this is being allocated using the devm for the coresight device */
+	config_csdev = devm_kzalloc(dev,
+				    offsetof(struct cscfg_config_csdev, feats_csdev[nr_feats]),
+				    GFP_KERNEL);
+	if (!config_csdev)
+		return NULL;
+
+	config_csdev->csdev = csdev;
+	return config_csdev;
+}
+
+/* Load a config into a device if there are any feature matches between config and device */
+static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
+			       struct cscfg_config_desc *config_desc)
+{
+	struct cscfg_config_csdev *config_csdev = NULL;
+	struct cscfg_feature_csdev *feat_csdev;
+	unsigned long flags;
+	int i;
+
+	/* look at each required feature and see if it matches any feature on the device */
+	for (i = 0; i < config_desc->nr_feat_refs; i++) {
+		/* look for a matching name */
+		feat_csdev = cscfg_get_feat_csdev(csdev, config_desc->feat_ref_names[i]);
+		if (feat_csdev) {
+			/*
+			 * At least one feature on this device matches the config
+			 * add a config instance to the device and a reference to the feature.
+			 */
+			if (!config_csdev) {
+				config_csdev = cscfg_alloc_csdev_cfg(csdev,
+								     config_desc->nr_feat_refs);
+				if (!config_csdev)
+					return -ENOMEM;
+				config_csdev->config_desc = config_desc;
+			}
+			config_csdev->feats_csdev[config_csdev->nr_feat++] = feat_csdev;
+		}
+	}
+	/* if matched features, add config to device.*/
+	if (config_csdev) {
+		spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+		list_add(&config_csdev->node, &csdev->config_csdev_list);
+		spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+	}
+
+	return 0;
+}
+
+/*
+ * Add the config to the set of registered devices - call with mutex locked.
+ * Iterates through devices - any device that matches one or more of the
+ * configuration features will load it, the others will ignore it.
+ */
+static int cscfg_add_cfg_to_csdevs(struct cscfg_config_desc *config_desc)
+{
+	struct cscfg_registered_csdev *csdev_item;
+	int err;
+
+	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
+		err = cscfg_add_csdev_cfg(csdev_item->csdev, config_desc);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/*
+ * Allocate a feature object for load into a csdev.
+ * memory allocated using the csdev->dev object using devm managed allocator.
+ */
+static struct cscfg_feature_csdev *
+cscfg_alloc_csdev_feat(struct coresight_device *csdev, struct cscfg_feature_desc *feat_desc)
+{
+	struct cscfg_feature_csdev *feat_csdev = NULL;
+	struct device *dev = csdev->dev.parent;
+	int i;
+
+	feat_csdev = devm_kzalloc(dev, sizeof(struct cscfg_feature_csdev), GFP_KERNEL);
+	if (!feat_csdev)
+		return NULL;
+
+	/* parameters are optional - could be 0 */
+	feat_csdev->nr_params = feat_desc->nr_params;
+
+	/*
+	 * if we need parameters, zero alloc the space here, the load routine in
+	 * the csdev device driver will fill out some information according to
+	 * feature descriptor.
+	 */
+	if (feat_csdev->nr_params) {
+		feat_csdev->params_csdev = devm_kcalloc(dev, feat_csdev->nr_params,
+							sizeof(struct cscfg_parameter_csdev),
+							GFP_KERNEL);
+		if (!feat_csdev->params_csdev)
+			return NULL;
+
+		/*
+		 * fill in the feature reference in the param - other fields
+		 * handled by loader in csdev.
+		 */
+		for (i = 0; i < feat_csdev->nr_params; i++)
+			feat_csdev->params_csdev[i].feat_csdev = feat_csdev;
+	}
+
+	/*
+	 * Always have registers to program - again the load routine in csdev device
+	 * will fill out according to feature descriptor and device requirements.
+	 */
+	feat_csdev->nr_regs = feat_desc->nr_regs;
+	feat_csdev->regs_csdev = devm_kcalloc(dev, feat_csdev->nr_regs,
+					      sizeof(struct cscfg_regval_csdev),
+					      GFP_KERNEL);
+	if (!feat_csdev->regs_csdev)
+		return NULL;
+
+	/* load the feature default values */
+	feat_csdev->feat_desc = feat_desc;
+	feat_csdev->csdev = csdev;
+
+	return feat_csdev;
+}
+
+/* load one feature into one coresight device */
+static int cscfg_load_feat_csdev(struct coresight_device *csdev,
+				 struct cscfg_feature_desc *feat_desc,
+				 struct cscfg_csdev_feat_ops *ops)
+{
+	struct cscfg_feature_csdev *feat_csdev;
+	unsigned long flags;
+	int err;
+
+	if (!ops->load_feat)
+		return -EINVAL;
+
+	feat_csdev = cscfg_alloc_csdev_feat(csdev, feat_desc);
+	if (!feat_csdev)
+		return -ENOMEM;
+
+	/* load the feature into the device */
+	err = ops->load_feat(csdev, feat_csdev);
+	if (err)
+		return err;
+
+	/* add to internal csdev feature list */
+	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	list_add(&feat_csdev->node, &csdev->feature_csdev_list);
+	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+
+	return 0;
+}
+
+/*
+ * Add feature to any matching devices - call with mutex locked.
+ * Iterates through devices - any device that matches the feature will be
+ * called to load it.
+ */
+static int cscfg_add_feat_to_csdevs(struct cscfg_feature_desc *feat_desc)
+{
+	struct cscfg_registered_csdev *csdev_item;
+	int err;
+
+	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
+		if (csdev_item->match_flags & feat_desc->match_flags) {
+			err = cscfg_load_feat_csdev(csdev_item->csdev, feat_desc, &csdev_item->ops);
+			if (err)
+				return err;
+		}
+	}
+	return 0;
+}
+
 /* check feature list for a named feature - call with mutex locked. */
 static bool cscfg_match_list_feat(const char *name)
 {
@@ -53,8 +245,14 @@ static int cscfg_check_feat_for_cfg(struct cscfg_config_desc *config_desc)
  */
 static int cscfg_load_feat(struct cscfg_feature_desc *feat_desc)
 {
-	list_add(&feat_desc->item, &cscfg_mgr->feat_desc_list);
+	int err;
+
+	/* add feature to any matching registered devices */
+	err = cscfg_add_feat_to_csdevs(feat_desc);
+	if (err)
+		return err;
 
+	list_add(&feat_desc->item, &cscfg_mgr->feat_desc_list);
 	return 0;
 }
 
@@ -71,6 +269,11 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc)
 	if (err)
 		return err;
 
+	/* add config to any matching registered device */
+	err = cscfg_add_cfg_to_csdevs(config_desc);
+	if (err)
+		return err;
+
 	list_add(&config_desc->item, &cscfg_mgr->config_desc_list);
 	return 0;
 }
@@ -125,6 +328,139 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 }
 EXPORT_SYMBOL_GPL(cscfg_load_config_sets);
 
+/* Handle coresight device registration and add configs and features to devices */
+
+/* iterate through config lists and load matching configs to device */
+static int cscfg_add_cfgs_csdev(struct coresight_device *csdev)
+{
+	struct cscfg_config_desc *config_desc;
+	int err = 0;
+
+	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
+		err = cscfg_add_csdev_cfg(csdev, config_desc);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/* iterate through feature lists and load matching features to device */
+static int cscfg_add_feats_csdev(struct coresight_device *csdev,
+				 u32 match_flags,
+				 struct cscfg_csdev_feat_ops *ops)
+{
+	struct cscfg_feature_desc *feat_desc;
+	int err = 0;
+
+	if (!ops->load_feat)
+		return -EINVAL;
+
+	list_for_each_entry(feat_desc, &cscfg_mgr->feat_desc_list, item) {
+		if (feat_desc->match_flags & match_flags) {
+			err = cscfg_load_feat_csdev(csdev, feat_desc, ops);
+			if (err)
+				break;
+		}
+	}
+	return err;
+}
+
+/* Add coresight device to list and copy its matching info */
+static int cscfg_list_add_csdev(struct coresight_device *csdev,
+				u32 match_flags,
+				struct cscfg_csdev_feat_ops *ops)
+{
+	struct cscfg_registered_csdev *csdev_item;
+
+	/* allocate the list entry structure */
+	csdev_item = kzalloc(sizeof(struct cscfg_registered_csdev), GFP_KERNEL);
+	if (!csdev_item)
+		return -ENOMEM;
+
+	csdev_item->csdev = csdev;
+	csdev_item->match_flags = match_flags;
+	csdev_item->ops.load_feat = ops->load_feat;
+	list_add(&csdev_item->item, &cscfg_mgr->csdev_desc_list);
+
+	INIT_LIST_HEAD(&csdev->feature_csdev_list);
+	INIT_LIST_HEAD(&csdev->config_csdev_list);
+	spin_lock_init(&csdev->cscfg_csdev_lock);
+
+	return 0;
+}
+
+/* remove a coresight device from the list and free data */
+static void cscfg_list_remove_csdev(struct coresight_device *csdev)
+{
+	struct cscfg_registered_csdev *csdev_item, *tmp;
+
+	list_for_each_entry_safe(csdev_item, tmp, &cscfg_mgr->csdev_desc_list, item) {
+		if (csdev_item->csdev == csdev) {
+			list_del(&csdev_item->item);
+			kfree(csdev_item);
+			break;
+		}
+	}
+}
+
+/**
+ * cscfg_register_csdev - register a coresight device with the syscfg manager.
+ *
+ * Registers the coresight device with the system. @match_flags used to check
+ * if the device is a match for registered features. Any currently registered
+ * configurations and features that match the device will be loaded onto it.
+ *
+ * @csdev:		The coresight device to register.
+ * @match_flags:	Matching information to load features.
+ * @ops:		Standard operations supported by the device.
+ */
+int cscfg_register_csdev(struct coresight_device *csdev,
+			 u32 match_flags,
+			 struct cscfg_csdev_feat_ops *ops)
+{
+	int ret = 0;
+
+	mutex_lock(&cscfg_mutex);
+
+	/* add device to list of registered devices  */
+	ret = cscfg_list_add_csdev(csdev, match_flags, ops);
+	if (ret)
+		goto reg_csdev_unlock;
+
+	/* now load any registered features and configs matching the device. */
+	ret = cscfg_add_feats_csdev(csdev, match_flags, ops);
+	if (ret) {
+		cscfg_list_remove_csdev(csdev);
+		goto reg_csdev_unlock;
+	}
+
+	ret = cscfg_add_cfgs_csdev(csdev);
+	if (ret) {
+		cscfg_list_remove_csdev(csdev);
+		goto reg_csdev_unlock;
+	}
+
+	pr_info("CSCFG registered %s", dev_name(&csdev->dev));
+
+reg_csdev_unlock:
+	mutex_unlock(&cscfg_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cscfg_register_csdev);
+
+/**
+ * cscfg_unregister_csdev - remove coresight device from syscfg manager.
+ *
+ * @csdev: Device to remove.
+ */
+void cscfg_unregister_csdev(struct coresight_device *csdev)
+{
+	mutex_lock(&cscfg_mutex);
+	cscfg_list_remove_csdev(csdev);
+	mutex_unlock(&cscfg_mutex);
+}
+EXPORT_SYMBOL_GPL(cscfg_unregister_csdev);
+
 /* Initialise system configuration management device. */
 
 struct device *cscfg_device(void)
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 18be9b58cd0b..5bcae3b374c6 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -35,6 +35,22 @@ struct cscfg_manager {
 /* get reference to dev in cscfg_manager */
 struct device *cscfg_device(void);
 
+/**
+ * List entry for Coresight devices that are registered as supporting complex
+ * config operations.
+ *
+ * @csdev:	 The registered device.
+ * @match_flags: The matching type information for adding features.
+ * @ops:	 Operations supported by the registered device.
+ * @item:	 list entry.
+ */
+struct cscfg_registered_csdev {
+	struct coresight_device *csdev;
+	u32 match_flags;
+	struct cscfg_csdev_feat_ops ops;
+	struct list_head item;
+};
+
 /* internal core operations for cscfg */
 int __init cscfg_init(void);
 void cscfg_exit(void);
@@ -42,5 +58,8 @@ void cscfg_exit(void);
 /* syscfg manager external API */
 int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
 			   struct cscfg_feature_desc **feat_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);
 
 #endif /* CORESIGHT_SYSCFG_H */
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 85008a65e21f..16544ae2b532 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -220,6 +220,9 @@ struct coresight_sysfs_link {
  * @nr_links:   number of sysfs links created to other components from this
  *		device. These will appear in the "connections" group.
  * @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.
+ * @cscfg_csdev_lock:	Protect the lists of configurations and features.
  */
 struct coresight_device {
 	struct coresight_platform_data *pdata;
@@ -241,6 +244,10 @@ struct coresight_device {
 	int nr_links;
 	bool has_conns_grp;
 	bool ect_enabled; /* true only if associated ect device is enabled */
+	/* system configuration and feature lists */
+	struct list_head feature_csdev_list;
+	struct list_head config_csdev_list;
+	spinlock_t cscfg_csdev_lock;
 };
 
 /*
-- 
2.25.1