+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nvdimm_bus_descriptor *nd_desc;
+ ssize_t rc = -ENXIO;
+
+ device_lock(dev);
+ nd_desc = dev_get_drvdata(dev);
+ if (nd_desc) {
+ struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+ rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+ (work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+ }
+ device_unlock(dev);
+ return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct nvdimm_bus_descriptor *nd_desc;
+ ssize_t rc;
+ long val;
+
+ rc = kstrtol(buf, 0, &val);
+ if (rc)
+ return rc;
+ if (val != 1)
+ return -EINVAL;
+
+ device_lock(dev);
+ nd_desc = dev_get_drvdata(dev);
+ if (nd_desc) {
+ struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+ rc = acpi_nfit_ars_rescan(acpi_desc);
+ }
+ device_unlock(dev);
+ if (rc)
+ return rc;
+ return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+ struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+ const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+ | 1 << ND_CMD_ARS_STATUS;
+
+ return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+ if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+ return 0;
+ return a->mode;
+}
+