[PATCH v4] net: stmmac: fix 'ethtool -P' return -EBUSY

[Hao Chen]

The permanent mac address should be available for query when the device
is not up.
NetworkManager, the system network daemon, uses 'ethtool -P' to obtain
the permanent address after the kernel start. When the network device
is not up, it will return the device busy error with 'ethtool -P'. At
that time, it is unable to access the Internet through the permanent
address by NetworkManager.
I think that the '.begin' is not used to check if the device is up.

Signed-off-by: Hao Chen <chenhaoa@xxxxxxxxxxxxx>
---
 .../ethernet/stmicro/stmmac/stmmac_ethtool.c  | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index d0ce608b81c3..25c44c1ecbd6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -15,6 +15,7 @@
 #include <linux/phylink.h>
 #include <linux/net_tstamp.h>
 #include <asm/io.h>
+#include <linux/pm_runtime.h>
 
 #include "stmmac.h"
 #include "dwmac_dma.h"
@@ -410,13 +411,22 @@ static void stmmac_ethtool_setmsglevel(struct net_device *dev, u32 level)
 
 }
 
-static int stmmac_check_if_running(struct net_device *dev)
+static int stmmac_ethtool_begin(struct net_device *dev)
 {
-	if (!netif_running(dev))
-		return -EBUSY;
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	pm_runtime_get_sync(priv->device);
+
 	return 0;
 }
 
+static void stmmac_ethtool_complete(struct net_device *dev)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	pm_runtime_put(priv->device);
+}
+
 static int stmmac_ethtool_get_regs_len(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
@@ -1073,7 +1083,8 @@ static int stmmac_set_tunable(struct net_device *dev,
 static const struct ethtool_ops stmmac_ethtool_ops = {
 	.supported_coalesce_params = ETHTOOL_COALESCE_USECS |
 				     ETHTOOL_COALESCE_MAX_FRAMES,
-	.begin = stmmac_check_if_running,
+	.begin = stmmac_ethtool_begin,
+	.complete = stmmac_ethtool_complete,
 	.get_drvinfo = stmmac_ethtool_getdrvinfo,
 	.get_msglevel = stmmac_ethtool_getmsglevel,
 	.set_msglevel = stmmac_ethtool_setmsglevel,
-- 
2.20.1