[v14,02/14] EDAC: Add scrub control feature

diff --git a/Documentation/ABI/testing/sysfs-edac-scrub b/Documentation/ABI/testing/sysfs-edac-scrub
new file mode 100644
index 000000000000..183a9c4e7139
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-edac-scrub
@@ -0,0 +1,74 @@ 
+What:		/sys/bus/edac/devices/<dev-name>/scrubX
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		The sysfs EDAC bus devices /<dev-name>/scrubX subdirectory
+		belongs to an instance of memory scrub control feature,
+		where <dev-name> directory corresponds to a device/memory
+		region registered with the EDAC device driver for the
+		scrub control feature.
+		The sysfs scrub attr nodes are only present if the
+		client driver has implemented the corresponding attr
+		callback function and passed in ops to the EDAC RAS feature
+		driver during registration.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/addr
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RW) The base address of the memory region to be scrubbed
+		for on-demand scrubbing. Setting address would start
+		scrubbing. The size must be set before that.
+		The readback addr value would be non-zero if the requested
+		on-demand scrubbing is in progress, zero otherwise.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/size
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RW) The size of the memory region to be scrubbed
+		(on-demand scrubbing).
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/enable_background
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RW) Start/Stop background(patrol) scrubbing if supported.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/enable_on_demand
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RW) Start/Stop on-demand scrubbing the memory region
+		if supported.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/min_cycle_duration
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RO) Supported minimum scrub cycle duration in seconds
+		by the memory scrubber.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/max_cycle_duration
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RO) Supported maximum scrub cycle duration in seconds
+		by the memory scrubber.
+
+What:		/sys/bus/edac/devices/<dev-name>/scrubX/current_cycle_duration
+Date:		Jan 2025
+KernelVersion:	6.13
+Contact:	linux-edac@vger.kernel.org
+Description:
+		(RW) The current scrub cycle duration in seconds and must be
+		within the supported range by the memory scrubber.
+		Scrub has an overhead when running and that may want to be
+		reduced by taking longer to do it.
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index faf310eec4a6..188501e676c7 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -10,6 +10,7 @@  obj-$(CONFIG_EDAC)			:= edac_core.o
 
 edac_core-y	:= edac_mc.o edac_device.o edac_mc_sysfs.o
 edac_core-y	+= edac_module.o edac_device_sysfs.o wq.o
+edac_core-y	+= scrub.o
 
 edac_core-$(CONFIG_EDAC_DEBUG)		+= debugfs.o
 
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index e9229b5f8afe..91552271b34a 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -576,6 +576,7 @@  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->scrub);
 	kfree(ctx->dev.groups);
 	kfree(ctx);
 }
@@ -609,6 +610,8 @@  int edac_dev_register(struct device *parent, char *name,
 		      const struct edac_dev_feature *ras_features)
 {
 	const struct attribute_group **ras_attr_groups;
+	int scrub_cnt = 0, scrub_inst = 0;
+	struct edac_dev_data *dev_data;
 	struct edac_dev_feat_ctx *ctx;
 	int attr_gcnt = 0;
 	int ret, feat;
@@ -619,7 +622,10 @@  int edac_dev_register(struct device *parent, char *name,
 	/* Double parse to make space for attributes */
 	for (feat = 0; feat < num_features; feat++) {
 		switch (ras_features[feat].ft_type) {
-		/* Add feature specific code */
+		case RAS_FEAT_SCRUB:
+			attr_gcnt++;
+			scrub_cnt++;
+			break;
 		default:
 			return -EINVAL;
 		}
@@ -635,13 +641,35 @@  int edac_dev_register(struct device *parent, char *name,
 		goto ctx_free;
 	}
 
+	if (scrub_cnt) {
+		ctx->scrub = kcalloc(scrub_cnt, sizeof(*ctx->scrub), GFP_KERNEL);
+		if (!ctx->scrub) {
+			ret = -ENOMEM;
+			goto groups_free;
+		}
+	}
+
 	attr_gcnt = 0;
 	for (feat = 0; feat < num_features; feat++, ras_features++) {
 		switch (ras_features->ft_type) {
-		/* Add feature specific code */
+		case RAS_FEAT_SCRUB:
+			if (!ras_features->scrub_ops ||
+			    scrub_inst != ras_features->instance)
+				goto data_mem_free;
+			dev_data = &ctx->scrub[scrub_inst];
+			dev_data->instance = scrub_inst;
+			dev_data->scrub_ops = ras_features->scrub_ops;
+			dev_data->private = ras_features->ctx;
+			ret = edac_scrub_get_desc(parent, &ras_attr_groups[attr_gcnt],
+						  ras_features->instance);
+			if (ret)
+				goto data_mem_free;
+			scrub_inst++;
+			attr_gcnt++;
+			break;
 		default:
 			ret = -EINVAL;
-			goto groups_free;
+			goto data_mem_free;
 		}
 	}
 
@@ -654,7 +682,7 @@  int edac_dev_register(struct device *parent, char *name,
 
 	ret = dev_set_name(&ctx->dev, name);
 	if (ret)
-		goto groups_free;
+		goto data_mem_free;
 
 	ret = device_register(&ctx->dev);
 	if (ret) {
@@ -664,6 +692,8 @@  int edac_dev_register(struct device *parent, char *name,
 
 	return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
 
+data_mem_free:
+	kfree(ctx->scrub);
 groups_free:
 	kfree(ras_attr_groups);
 ctx_free:
diff --git a/drivers/edac/scrub.c b/drivers/edac/scrub.c
new file mode 100755
index 000000000000..bf76d95382af
--- /dev/null
+++ b/drivers/edac/scrub.c
@@ -0,0 +1,211 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic EDAC scrub driver in order to control the memory
+ * scrubbers in the system and the common sysfs scrub interface
+ * abstracts the control of an arbitrary scrubbing functionality
+ * to a common set of functions.
+ *
+ * Copyright (c) 2024 HiSilicon Limited.
+ */
+
+#define pr_fmt(fmt)     "EDAC SCRUB: " fmt
+
+#include <linux/edac.h>
+
+enum edac_scrub_attributes {
+	SCRUB_ADDRESS,
+	SCRUB_SIZE,
+	SCRUB_ENABLE_BACKGROUND,
+	SCRUB_MIN_CYCLE_DURATION,
+	SCRUB_MAX_CYCLE_DURATION,
+	SCRUB_CUR_CYCLE_DURATION,
+	SCRUB_MAX_ATTRS
+};
+
+struct edac_scrub_dev_attr {
+	struct device_attribute dev_attr;
+	u8 instance;
+};
+
+struct edac_scrub_context {
+	char name[EDAC_FEAT_NAME_LEN];
+	struct edac_scrub_dev_attr scrub_dev_attr[SCRUB_MAX_ATTRS];
+	struct attribute *scrub_attrs[SCRUB_MAX_ATTRS + 1];
+	struct attribute_group group;
+};
+
+#define TO_SCRUB_DEV_ATTR(_dev_attr)      \
+		container_of(_dev_attr, struct edac_scrub_dev_attr, dev_attr)
+
+#define EDAC_SCRUB_ATTR_SHOW(attrib, cb, type, format)				\
+static ssize_t attrib##_show(struct device *ras_feat_dev,			\
+			     struct device_attribute *attr, char *buf)		\
+{										\
+	u8 inst = TO_SCRUB_DEV_ATTR(attr)->instance;				\
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);		\
+	const struct edac_scrub_ops *ops = ctx->scrub[inst].scrub_ops;		\
+	type data;								\
+	int ret;								\
+										\
+	ret = ops->cb(ras_feat_dev->parent, ctx->scrub[inst].private, &data);	\
+	if (ret)								\
+		return ret;							\
+										\
+	return sysfs_emit(buf, format, data);					\
+}
+
+EDAC_SCRUB_ATTR_SHOW(addr, read_addr, u64, "0x%llx\n")
+EDAC_SCRUB_ATTR_SHOW(size, read_size, u64, "0x%llx\n")
+EDAC_SCRUB_ATTR_SHOW(enable_background, get_enabled_bg, bool, "%u\n")
+EDAC_SCRUB_ATTR_SHOW(min_cycle_duration, get_min_cycle, u32, "%u\n")
+EDAC_SCRUB_ATTR_SHOW(max_cycle_duration, get_max_cycle, u32, "%u\n")
+EDAC_SCRUB_ATTR_SHOW(current_cycle_duration, get_cycle_duration, u32, "%u\n")
+
+#define EDAC_SCRUB_ATTR_STORE(attrib, cb, type, conv_func)			\
+static ssize_t attrib##_store(struct device *ras_feat_dev,			\
+			      struct device_attribute *attr,			\
+			      const char *buf, size_t len)			\
+{										\
+	u8 inst = TO_SCRUB_DEV_ATTR(attr)->instance;				\
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);		\
+	const struct edac_scrub_ops *ops = ctx->scrub[inst].scrub_ops;		\
+	type data;								\
+	int ret;								\
+										\
+	ret = conv_func(buf, 0, &data);						\
+	if (ret < 0)								\
+		return ret;							\
+										\
+	ret = ops->cb(ras_feat_dev->parent, ctx->scrub[inst].private, data);	\
+	if (ret)								\
+		return ret;							\
+										\
+	return len;								\
+}
+
+EDAC_SCRUB_ATTR_STORE(addr, write_addr, u64, kstrtou64)
+EDAC_SCRUB_ATTR_STORE(size, write_size, u64, kstrtou64)
+EDAC_SCRUB_ATTR_STORE(enable_background, set_enabled_bg, unsigned long, kstrtoul)
+EDAC_SCRUB_ATTR_STORE(current_cycle_duration, set_cycle_duration, unsigned long, kstrtoul)
+
+static umode_t scrub_attr_visible(struct kobject *kobj, struct attribute *a, int attr_id)
+{
+	struct device *ras_feat_dev = kobj_to_dev(kobj);
+	struct device_attribute *dev_attr = container_of(a, struct device_attribute, attr);
+	u8 inst = TO_SCRUB_DEV_ATTR(dev_attr)->instance;
+	struct edac_dev_feat_ctx *ctx = dev_get_drvdata(ras_feat_dev);
+	const struct edac_scrub_ops *ops = ctx->scrub[inst].scrub_ops;
+
+	switch (attr_id) {
+	case SCRUB_ADDRESS:
+		if (ops->read_addr) {
+			if (ops->write_addr)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case SCRUB_SIZE:
+		if (ops->read_size) {
+			if (ops->write_size)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case SCRUB_ENABLE_BACKGROUND:
+		if (ops->get_enabled_bg) {
+			if (ops->set_enabled_bg)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	case SCRUB_MIN_CYCLE_DURATION:
+		if (ops->get_min_cycle)
+			return a->mode;
+		break;
+	case SCRUB_MAX_CYCLE_DURATION:
+		if (ops->get_max_cycle)
+			return a->mode;
+		break;
+	case SCRUB_CUR_CYCLE_DURATION:
+		if (ops->get_cycle_duration) {
+			if (ops->set_cycle_duration)
+				return a->mode;
+			else
+				return 0444;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+#define EDAC_SCRUB_ATTR_RO(_name, _instance)       \
+	((struct edac_scrub_dev_attr) { .dev_attr = __ATTR_RO(_name), \
+					.instance = _instance })
+
+#define EDAC_SCRUB_ATTR_WO(_name, _instance)       \
+	((struct edac_scrub_dev_attr) { .dev_attr = __ATTR_WO(_name), \
+					.instance = _instance })
+
+#define EDAC_SCRUB_ATTR_RW(_name, _instance)       \
+	((struct edac_scrub_dev_attr) { .dev_attr = __ATTR_RW(_name), \
+					.instance = _instance })
+
+static int scrub_create_desc(struct device *scrub_dev,
+			     const struct attribute_group **attr_groups, u8 instance)
+{
+	struct edac_scrub_context *scrub_ctx;
+	struct attribute_group *group;
+	int i;
+	struct edac_scrub_dev_attr dev_attr[] = {
+		[SCRUB_ADDRESS] = EDAC_SCRUB_ATTR_RW(addr, instance),
+		[SCRUB_SIZE] = EDAC_SCRUB_ATTR_RW(size, instance),
+		[SCRUB_ENABLE_BACKGROUND] = EDAC_SCRUB_ATTR_RW(enable_background, instance),
+		[SCRUB_MIN_CYCLE_DURATION] = EDAC_SCRUB_ATTR_RO(min_cycle_duration, instance),
+		[SCRUB_MAX_CYCLE_DURATION] = EDAC_SCRUB_ATTR_RO(max_cycle_duration, instance),
+		[SCRUB_CUR_CYCLE_DURATION] = EDAC_SCRUB_ATTR_RW(current_cycle_duration, instance)
+	};
+
+	scrub_ctx = devm_kzalloc(scrub_dev, sizeof(*scrub_ctx), GFP_KERNEL);
+	if (!scrub_ctx)
+		return -ENOMEM;
+
+	group = &scrub_ctx->group;
+	for (i = 0; i < SCRUB_MAX_ATTRS; i++) {
+		memcpy(&scrub_ctx->scrub_dev_attr[i], &dev_attr[i], sizeof(dev_attr[i]));
+		scrub_ctx->scrub_attrs[i] = &scrub_ctx->scrub_dev_attr[i].dev_attr.attr;
+	}
+	sprintf(scrub_ctx->name, "%s%d", "scrub", instance);
+	group->name = scrub_ctx->name;
+	group->attrs = scrub_ctx->scrub_attrs;
+	group->is_visible  = scrub_attr_visible;
+
+	attr_groups[0] = group;
+
+	return 0;
+}
+
+/**
+ * edac_scrub_get_desc - get EDAC scrub descriptors
+ * @scrub_dev: client device, with scrub support
+ * @attr_groups: pointer to attribute group container
+ * @instance: device's scrub instance number.
+ *
+ * Return:
+ *  * %0	- Success.
+ *  * %-EINVAL	- Invalid parameters passed.
+ *  * %-ENOMEM	- Dynamic memory allocation failed.
+ */
+int edac_scrub_get_desc(struct device *scrub_dev,
+			const struct attribute_group **attr_groups, u8 instance)
+{
+	if (!scrub_dev || !attr_groups)
+		return -EINVAL;
+
+	return scrub_create_desc(scrub_dev, attr_groups, instance);
+}
diff --git a/include/linux/edac.h b/include/linux/edac.h
index e19706311ec0..3620a09c0476 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -668,11 +668,43 @@  static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,
 
 /* RAS feature type */
 enum edac_dev_feat {
+	RAS_FEAT_SCRUB,
 	RAS_FEAT_MAX
 };
 
+/**
+ * struct edac_scrub_ops - scrub device operations (all elements optional)
+ * @read_addr: read base address of scrubbing range.
+ * @read_size: read offset of scrubbing range.
+ * @write_addr: set base address of the scrubbing range.
+ * @write_size: set offset of the scrubbing range.
+ * @get_enabled_bg: check if currently performing background scrub.
+ * @set_enabled_bg: start or stop a bg-scrub.
+ * @get_min_cycle: get minimum supported scrub cycle duration in seconds.
+ * @get_max_cycle: get maximum supported scrub cycle duration in seconds.
+ * @get_cycle_duration: get current scrub cycle duration in seconds.
+ * @set_cycle_duration: set current scrub cycle duration in seconds.
+ */
+struct edac_scrub_ops {
+	int (*read_addr)(struct device *dev, void *drv_data, u64 *base);
+	int (*read_size)(struct device *dev, void *drv_data, u64 *size);
+	int (*write_addr)(struct device *dev, void *drv_data, u64 base);
+	int (*write_size)(struct device *dev, void *drv_data, u64 size);
+	int (*get_enabled_bg)(struct device *dev, void *drv_data, bool *enable);
+	int (*set_enabled_bg)(struct device *dev, void *drv_data, bool enable);
+	int (*get_min_cycle)(struct device *dev, void *drv_data,  u32 *min);
+	int (*get_max_cycle)(struct device *dev, void *drv_data,  u32 *max);
+	int (*get_cycle_duration)(struct device *dev, void *drv_data, u32 *cycle);
+	int (*set_cycle_duration)(struct device *dev, void *drv_data, u32 cycle);
+};
+
+int edac_scrub_get_desc(struct device *scrub_dev,
+			const struct attribute_group **attr_groups,
+			u8 instance);
+
 /* EDAC device feature information structure */
 struct edac_dev_data {
+	const struct edac_scrub_ops *scrub_ops;
 	u8 instance;
 	void *private;
 };
@@ -680,11 +712,13 @@  struct edac_dev_data {
 struct edac_dev_feat_ctx {
 	struct device dev;
 	void *private;
+	struct edac_dev_data *scrub;
 };
 
 struct edac_dev_feature {
 	enum edac_dev_feat ft_type;
 	u8 instance;
+	const struct edac_scrub_ops *scrub_ops;
 	void *ctx;
 };