powerpc/eeh: Add restore_config operation

After reset on the specific PE or PHB, we never configure AER
correctly on PowerNV platform. We needn't care it on pSeries
platform. The patch introduces additional EEH operation eeh_ops::
restore_config() so that we have chance to configure AER correctly
for PowerNV platform.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/eeh.h

@@ -157,6 +157,7 @@ struct eeh_ops {
 	int (*read_config)(struct device_node *dn, int where, int size, u32 *val);
 	int (*write_config)(struct device_node *dn, int where, int size, u32 val);
 	int (*next_error)(struct eeh_pe **pe);
+	int (*restore_config)(struct device_node *dn);
 };
 
 extern struct eeh_ops *eeh_ops;

arch/powerpc/kernel/eeh_pe.c

@@ -736,6 +736,9 @@ static void *eeh_restore_one_device_bars(void *data, void *flag)
 	else
 		eeh_restore_device_bars(edev, dn);
 
+	if (eeh_ops->restore_config)
+		eeh_ops->restore_config(dn);
+
 	return NULL;
 }
 

arch/powerpc/platforms/powernv/eeh-powernv.c

@@ -359,7 +359,8 @@ static struct eeh_ops powernv_eeh_ops = {
 	.configure_bridge       = powernv_eeh_configure_bridge,
 	.read_config            = pnv_pci_cfg_read,
 	.write_config           = pnv_pci_cfg_write,
-	.next_error		= powernv_eeh_next_error
+	.next_error		= powernv_eeh_next_error,
+	.restore_config		= NULL
 };
 
 /**

arch/powerpc/platforms/pseries/eeh_pseries.c

@@ -689,7 +689,9 @@ static struct eeh_ops pseries_eeh_ops = {
 	.get_log		= pseries_eeh_get_log,
 	.configure_bridge       = pseries_eeh_configure_bridge,
 	.read_config		= pseries_eeh_read_config,
-	.write_config		= pseries_eeh_write_config
+	.write_config		= pseries_eeh_write_config,
+	.next_error		= NULL,
+	.restore_config		= NULL
 };
 
 /**