s390/pci: add recover sysfs knob

Add an arch specific attribute to recover a pci function from an
error state or config space blockage.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci.c

@@ -791,6 +791,8 @@ int zpci_enable_device(struct zpci_dev *zdev)
 	rc = zpci_dma_init_device(zdev);
 	if (rc)
 		goto out_dma;
+
+	zdev->state = ZPCI_FN_STATE_ONLINE;
 	return 0;
 
 out_dma:
@@ -819,8 +821,6 @@ int zpci_create_device(struct zpci_dev *zdev)
 		rc = zpci_enable_device(zdev);
 		if (rc)
 			goto out_free;
-
-		zdev->state = ZPCI_FN_STATE_ONLINE;
 	}
 	rc = zpci_scan_bus(zdev);
 	if (rc)

arch/s390/pci/pci_sysfs.c

@@ -48,11 +48,38 @@ static ssize_t show_pfgid(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR(pfgid, S_IRUGO, show_pfgid, NULL);
 
+static void recover_callback(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct zpci_dev *zdev = get_zdev(pdev);
+	int ret;
+
+	pci_stop_and_remove_bus_device(pdev);
+	ret = zpci_disable_device(zdev);
+	if (ret)
+		return;
+
+	ret = zpci_enable_device(zdev);
+	if (ret)
+		return;
+
+	pci_rescan_bus(zdev->bus);
+}
+
+static ssize_t store_recover(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	int rc = device_schedule_callback(dev, recover_callback);
+	return rc ? rc : count;
+}
+static DEVICE_ATTR(recover, S_IWUSR, NULL, store_recover);
+
 static struct device_attribute *zpci_dev_attrs[] = {
 	&dev_attr_function_id,
 	&dev_attr_function_handle,
 	&dev_attr_pchid,
 	&dev_attr_pfgid,
+	&dev_attr_recover,
 	NULL,
 };
 

drivers/pci/hotplug/s390_pci_hpc.c

@@ -79,8 +79,6 @@ static int enable_slot(struct hotplug_slot *hotplug_slot)
 	if (rc)
 		goto out_deconfigure;
 
-	slot->zdev->state = ZPCI_FN_STATE_ONLINE;
-
 	pci_scan_slot(slot->zdev->bus, ZPCI_DEVFN);
 	pci_bus_add_devices(slot->zdev->bus);