[PATCH net-next] net: renesas: rswitch: cleanup max_speed setting

[Nikita Yushchenko]

It was observed on spider board that with upstream kernel, PHY
auto-negotiation takes almost 1 second longer than with renesas BSP
kernel. This was tracked down to upstream kernel allowing more PHY modes
than renesas BSP kernel.

To avoid that effect when possible, always set max_speed to not more
than phy_interface allows.

While at this, also ensure that etha->speed always gets a supported
value, even if max_speed in device tree is set to something else.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/renesas/rswitch.c | 48 ++++++++++++++------------
 drivers/net/ethernet/renesas/rswitch.h |  1 +
 2 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
index 84d09a8973b7..4b4e174e3abb 100644
--- a/drivers/net/ethernet/renesas/rswitch.c
+++ b/drivers/net/ethernet/renesas/rswitch.c
@@ -1308,37 +1308,41 @@ static struct device_node *rswitch_get_port_node(struct rswitch_device *rdev)
 
 static int rswitch_etha_get_params(struct rswitch_device *rdev)
 {
-	u32 max_speed;
+	struct rswitch_etha *etha = rdev->etha;
 	int err;
 
 	if (!rdev->np_port)
 		return 0;	/* ignored */
 
-	err = of_get_phy_mode(rdev->np_port, &rdev->etha->phy_interface);
+	err = of_get_phy_mode(rdev->np_port, &etha->phy_interface);
 	if (err)
 		return err;
 
-	err = of_property_read_u32(rdev->np_port, "max-speed", &max_speed);
-	if (!err) {
-		rdev->etha->speed = max_speed;
-		return 0;
-	}
-
-	/* if no "max-speed" property, let's use default speed */
-	switch (rdev->etha->phy_interface) {
-	case PHY_INTERFACE_MODE_MII:
-		rdev->etha->speed = SPEED_100;
-		break;
+	switch (etha->phy_interface) {
 	case PHY_INTERFACE_MODE_SGMII:
-		rdev->etha->speed = SPEED_1000;
+		etha->max_speed = SPEED_1000;
 		break;
 	case PHY_INTERFACE_MODE_USXGMII:
-		rdev->etha->speed = SPEED_2500;
+	case PHY_INTERFACE_MODE_5GBASER:
+		etha->max_speed = SPEED_2500;
 		break;
 	default:
 		return -EINVAL;
 	}
 
+	/* Allow max_speed override */
+	of_property_read_u32(rdev->np_port, "max-speed", &etha->max_speed);
+
+	/* Set etha->speed to one of values expected by the driver */
+	if (etha->max_speed < SPEED_100)
+		return -EINVAL;
+	else if (etha->max_speed < SPEED_1000)
+		etha->speed = SPEED_100;
+	else if (etha->max_speed < SPEED_2500)
+		etha->speed = SPEED_1000;
+	else
+		etha->speed = SPEED_2500;
+
 	return 0;
 }
 
@@ -1412,6 +1416,13 @@ static void rswitch_adjust_link(struct net_device *ndev)
 static void rswitch_phy_remove_link_mode(struct rswitch_device *rdev,
 					 struct phy_device *phydev)
 {
+	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_10baseT_Half_BIT);
+	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_10baseT_Full_BIT);
+	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_100baseT_Half_BIT);
+	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_1000baseT_Half_BIT);
+
+	phy_set_max_speed(phydev, rdev->etha->max_speed);
+
 	if (!rdev->priv->etha_no_runtime_change)
 		return;
 
@@ -1431,8 +1442,6 @@ static void rswitch_phy_remove_link_mode(struct rswitch_device *rdev,
 	default:
 		break;
 	}
-
-	phy_set_max_speed(phydev, rdev->etha->speed);
 }
 
 static int rswitch_phy_device_init(struct rswitch_device *rdev)
@@ -1462,11 +1471,6 @@ static int rswitch_phy_device_init(struct rswitch_device *rdev)
 	if (!phydev)
 		goto out;
 
-	phy_set_max_speed(phydev, SPEED_2500);
-	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_10baseT_Half_BIT);
-	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_10baseT_Full_BIT);
-	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_100baseT_Half_BIT);
-	phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_1000baseT_Half_BIT);
 	rswitch_phy_remove_link_mode(rdev, phydev);
 
 	phy_attached_info(phydev);
diff --git a/drivers/net/ethernet/renesas/rswitch.h b/drivers/net/ethernet/renesas/rswitch.h
index 532192cbca4b..09f5d5e1933e 100644
--- a/drivers/net/ethernet/renesas/rswitch.h
+++ b/drivers/net/ethernet/renesas/rswitch.h
@@ -920,6 +920,7 @@ struct rswitch_etha {
 	bool external_phy;
 	struct mii_bus *mii;
 	phy_interface_t phy_interface;
+	u32 max_speed;
 	u32 psmcs;
 	u8 mac_addr[MAX_ADDR_LEN];
 	int link;
-- 
2.39.5