From: Shiju Jose <shiju.jose@huawei.com>

Add generic EDAC device feature controls supporting the registration
of RAS features available in the system. The driver exposes control
attributes for these features to userspace in
/sys/bus/edac/devices/<dev-name>/<ras-feature>/

Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 drivers/edac/edac_device.c | 101 +++++++++++++++++++++++++++++++++++++
 include/linux/edac.h       |  30 +++++++++++
 2 files changed, 131 insertions(+)

diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index 621dc2a5d034..e9229b5f8afe 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -570,3 +570,104 @@ void edac_device_handle_ue_count(struct edac_device_ctl_info *edac_dev,
 		      block ? block->name : "N/A", count, msg);
 }
 EXPORT_SYMBOL_GPL(edac_device_handle_ue_count);
+
+/* EDAC device feature */
+static void edac_dev_release(struct device *dev)
+{
+	struct edac_dev_feat_ctx *ctx = container_of(dev, struct edac_dev_feat_ctx, dev);
+
+	kfree(ctx->dev.groups);
+	kfree(ctx);
+}
+
+const struct device_type edac_dev_type = {
+	.name = "edac_dev",
+	.release = edac_dev_release,
+};
+
+static void edac_dev_unreg(void *data)
+{
+	device_unregister(data);
+}
+
+/**
+ * edac_dev_register - register device for RAS features with EDAC
+ * @parent: parent device.
+ * @name: parent device's name.
+ * @private: parent driver's data to store in the context if any.
+ * @num_features: number of RAS features to register.
+ * @ras_features: list of RAS features to register.
+ *
+ * Return:
+ *  * %0       - Success.
+ *  * %-EINVAL - Invalid parameters passed.
+ *  * %-ENOMEM - Dynamic memory allocation failed.
+ *
+ */
+int edac_dev_register(struct device *parent, char *name,
+		      void *private, int num_features,
+		      const struct edac_dev_feature *ras_features)
+{
+	const struct attribute_group **ras_attr_groups;
+	struct edac_dev_feat_ctx *ctx;
+	int attr_gcnt = 0;
+	int ret, feat;
+
+	if (!parent || !name || !num_features || !ras_features)
+		return -EINVAL;
+
+	/* Double parse to make space for attributes */
+	for (feat = 0; feat < num_features; feat++) {
+		switch (ras_features[feat].ft_type) {
+		/* Add feature specific code */
+		default:
+			return -EINVAL;
+		}
+	}
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ras_attr_groups = kcalloc(attr_gcnt + 1, sizeof(*ras_attr_groups), GFP_KERNEL);
+	if (!ras_attr_groups) {
+		ret = -ENOMEM;
+		goto ctx_free;
+	}
+
+	attr_gcnt = 0;
+	for (feat = 0; feat < num_features; feat++, ras_features++) {
+		switch (ras_features->ft_type) {
+		/* Add feature specific code */
+		default:
+			ret = -EINVAL;
+			goto groups_free;
+		}
+	}
+
+	ctx->dev.parent = parent;
+	ctx->dev.bus = edac_get_sysfs_subsys();
+	ctx->dev.type = &edac_dev_type;
+	ctx->dev.groups = ras_attr_groups;
+	ctx->private = private;
+	dev_set_drvdata(&ctx->dev, ctx);
+
+	ret = dev_set_name(&ctx->dev, name);
+	if (ret)
+		goto groups_free;
+
+	ret = device_register(&ctx->dev);
+	if (ret) {
+		put_device(&ctx->dev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
+
+groups_free:
+	kfree(ras_attr_groups);
+ctx_free:
+	kfree(ctx);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(edac_dev_register);
diff --git a/include/linux/edac.h b/include/linux/edac.h
index b4ee8961e623..e19706311ec0 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -661,4 +661,34 @@ static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,
 
 	return mci->dimms[index];
 }
+
+/* EDAC device features */
+
+#define EDAC_FEAT_NAME_LEN	128
+
+/* RAS feature type */
+enum edac_dev_feat {
+	RAS_FEAT_MAX
+};
+
+/* EDAC device feature information structure */
+struct edac_dev_data {
+	u8 instance;
+	void *private;
+};
+
+struct edac_dev_feat_ctx {
+	struct device dev;
+	void *private;
+};
+
+struct edac_dev_feature {
+	enum edac_dev_feat ft_type;
+	u8 instance;
+	void *ctx;
+};
+
+int edac_dev_register(struct device *parent, char *dev_name,
+		      void *parent_pvt_data, int num_features,
+		      const struct edac_dev_feature *ras_features);
 #endif /* _LINUX_EDAC_H_ */
-- 
2.34.1