EDAC: Add scrub control feature

Add a scrub control to manage memory scrubbers in the system.

Devices with a scrub feature register with the EDAC device driver which
retrieves the scrub descriptor from the scrub driver and exposes the
control attributes for a instance to userspace at

  /sys/bus/edac/devices/<dev-name>/scrubX/.

The common sysfs scrub control interface abstracts the control of
arbitrary scrubbing functionality into a common set of functions. The
attribute nodes are only present if the client driver has implemented
the corresponding attribute callback function and passed the operations
to the device driver during registration.

  [ bp: Massage commit message, docs and code, simplify text a bit.
    Integrate fixup for: https://lore.kernel.org/r/202502251009.0sGkolEJ-lkp@intel.com
    Reported-by: kernel test robot <lkp@intel.com>
    Reported-by: Dan Carpenter <dan.carpenter@linaro.org> ]

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>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Daniel Ferguson <danielf@os.amperecomputing.com>
Tested-by: Fan Ni <fan.ni@samsung.com>
Link: https://lore.kernel.org/r/20250212143654.1893-3-shiju.jose@huawei.com

4 files changed, 255 insertions, 4 deletions

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 2051a7c944a5..175d706168ab 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -75,6 +75,15 @@ config EDAC_GHES
 
 	  In doubt, say 'Y'.
 
+config EDAC_SCRUB
+	bool "EDAC scrub feature"
+	help
+	  The EDAC scrub feature is optional and is designed to control the
+	  memory scrubbers in the system. The common sysfs scrub interface
+	  abstracts the control of various arbitrary scrubbing functionalities
+	  into a unified set of functions.
+	  Say 'y/n' to enable/disable EDAC scrub feature.
+
 config EDAC_AMD64
 	tristate "AMD64 (Opteron, Athlon64)"
 	depends on AMD_NB && EDAC_DECODE_MCE
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 89789ba8275f..cdbd0a07b9e6 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -12,6 +12,7 @@ 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-$(CONFIG_EDAC_DEBUG)		+= debugfs.o
+edac_core-$(CONFIG_EDAC_SCRUB)		+= scrub.o
 
 ifdef CONFIG_PCI
 edac_core-y	+= edac_pci.o edac_pci_sysfs.o
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index 6af0893cadc9..54c1e2d024ac 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -575,6 +575,7 @@ 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);
 }
@@ -610,9 +611,11 @@ int edac_dev_register(struct device *parent, char *name,
 		      const struct edac_dev_feature *ras_features)
 {
 	const struct attribute_group **ras_attr_groups;
+	struct edac_dev_data *dev_data;
 	struct edac_dev_feat_ctx *ctx;
 	int attr_gcnt = 0;
 	int ret = -ENOMEM;
+	int scrub_cnt = 0;
 	int feat;
 
 	if (!parent || !name || !num_features || !ras_features)
@@ -621,7 +624,10 @@ 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 +641,37 @@ int edac_dev_register(struct device *parent, char *name,
 	if (!ras_attr_groups)
 		goto ctx_free;
 
+	if (scrub_cnt) {
+		ctx->scrub = kcalloc(scrub_cnt, sizeof(*ctx->scrub), GFP_KERNEL);
+		if (!ctx->scrub)
+			goto groups_free;
+	}
+
 	attr_gcnt = 0;
+	scrub_cnt = 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_cnt != ras_features->instance) {
+				ret = -EINVAL;
+				goto data_mem_free;
+			}
+
+			dev_data = &ctx->scrub[scrub_cnt];
+			dev_data->instance = scrub_cnt;
+			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_cnt++;
+			attr_gcnt++;
+			break;
 		default:
 			ret = -EINVAL;
-			goto groups_free;
+			goto data_mem_free;
 		}
 	}
 
@@ -654,7 +684,7 @@ 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 +694,8 @@ 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..e421d3ebd959
--- /dev/null
+++ b/drivers/edac/scrub.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * The generic EDAC scrub driver controls the memory scrubbers in the
+ * system. The common sysfs scrub interface abstracts the control of
+ * various arbitrary scrubbing functionalities into a unified set of
+ * functions.
+ *
+ * Copyright (c) 2024-2025 HiSilicon Limited.
+ */
+
+#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);
+}