[PATCH net-next] net: stmmac: allow ethtool action on PCI devices if device is down

[Corinna Vinschen <vinschen@redhat.com>]

So far stmmac is only able to handle ethtool commands if the device
is UP.  However, PCI devices usually just have to be in the active
state for ethtool commands.

Rename stmmac_check_if_running to stmmac_ethtool_begin and add a
stmmac_ethtool_complete action.  Check if the device is connected
to PCI and if so, just make sure the device is active.  Reset it
to idle state as complete action.

Tested on Intel Elkhart Lake system.

Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
---
 .../ethernet/stmicro/stmmac/stmmac_ethtool.c  | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 35c8dd92d369..5a57970dc06a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -14,6 +14,7 @@
 #include <linux/mii.h>
 #include <linux/phylink.h>
 #include <linux/net_tstamp.h>
+#include <linux/pm_runtime.h>
 #include <asm/io.h>
 
 #include "stmmac.h"
@@ -429,13 +430,27 @@ 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)
 {
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	if (priv->plat->pdev) {
+		pm_runtime_get_sync(&priv->plat->pdev->dev);
+		return 0;
+	}
 	if (!netif_running(dev))
 		return -EBUSY;
 	return 0;
 }
 
+static void stmmac_ethtool_complete(struct net_device *dev)
+{
+	struct stmmac_priv *priv = netdev_priv(dev);
+
+	if (priv->plat->pdev)
+		pm_runtime_put(&priv->plat->pdev->dev);
+}
+
 static int stmmac_ethtool_get_regs_len(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
@@ -1152,7 +1167,8 @@ 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,
-- 
2.39.2