acpi/nfit: Add support of NVDIMM memory error notification in ACPI 6.2

ACPI 6.2 defines a new ACPI notification value to NVDIMM Root Device
in Table 5-169.

 0x81 Unconsumed Uncorrectable Memory Error Detected
      Used to pro-actively notify OSPM of uncorrectable memory errors
      detected (for example a memory scrubbing engine that continuously
      scans the NVDIMMs memory). This is an optional notification. Only
      locations that were mapped in to SPA by the platform will generate
      a notification.

Add support of this notification value by initiating an ARS scan. This
will find new error locations and add their badblocks information.

Link: http://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/acpi/nfit/core.c

@@ -3016,7 +3016,7 @@ static int acpi_nfit_remove(struct acpi_device *adev)
 	return 0;
 }
 
-void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
+static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle)
 {
 	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(dev);
 	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -3024,11 +3024,6 @@ void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
 	acpi_status status;
 	int ret;
 
-	dev_dbg(dev, "%s: event: %d\n", __func__, event);
-
-	if (event != NFIT_NOTIFY_UPDATE)
-		return;
-
 	if (!dev->driver) {
 		/* dev->driver may be null if we're being removed */
 		dev_dbg(dev, "%s: no driver found for dev\n", __func__);
@@ -3065,6 +3060,27 @@ void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
 		dev_err(dev, "Invalid _FIT\n");
 	kfree(buf.pointer);
 }
+
+static void acpi_nfit_uc_error_notify(struct device *dev, acpi_handle handle)
+{
+	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(dev);
+
+	acpi_nfit_ars_rescan(acpi_desc);
+}
+
+void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
+{
+	dev_dbg(dev, "%s: event: 0x%x\n", __func__, event);
+
+	switch (event) {
+	case NFIT_NOTIFY_UPDATE:
+		return acpi_nfit_update_notify(dev, handle);
+	case NFIT_NOTIFY_UC_MEMORY_ERROR:
+		return acpi_nfit_uc_error_notify(dev, handle);
+	default:
+		return;
+	}
+}
 EXPORT_SYMBOL_GPL(__acpi_nfit_notify);
 
 static void acpi_nfit_notify(struct acpi_device *adev, u32 event)

drivers/acpi/nfit/nfit.h

@@ -79,6 +79,7 @@ enum {
 
 enum nfit_root_notifiers {
 	NFIT_NOTIFY_UPDATE = 0x80,
+	NFIT_NOTIFY_UC_MEMORY_ERROR = 0x81,
 };
 
 enum nfit_dimm_notifiers {