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

1 files changed, 43 insertions, 0 deletions

diff --git a/include/linux/edac.h b/include/linux/edac.h
index 8c4b6ca2a994..1cbab08720df 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -662,13 +662,54 @@ static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,
 	return mci->dimms[index];
 }
 
+#define EDAC_FEAT_NAME_LEN	128
+
 /* 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);
+};
+
+#if IS_ENABLED(CONFIG_EDAC_SCRUB)
+int edac_scrub_get_desc(struct device *scrub_dev,
+			const struct attribute_group **attr_groups,
+			u8 instance);
+#else
+static inline int edac_scrub_get_desc(struct device *scrub_dev,
+				      const struct attribute_group **attr_groups,
+				      u8 instance)
+{ return -EOPNOTSUPP; }
+#endif /* CONFIG_EDAC_SCRUB */
+
 /* EDAC device feature information structure */
 struct edac_dev_data {
+	const struct edac_scrub_ops *scrub_ops;
 	u8 instance;
 	void *private;
 };
@@ -676,11 +717,13 @@ 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;
 };