net: renesas: rswitch: Add runtime speed change support

The latest SoC version can support runtime speed change. So,
add detect SoC version by using soc_device_match() and then
reconfigure the hardware of this and SerDes if needed.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230807003231.1552062-2-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/renesas/rswitch.c

@@ -20,6 +20,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/sys_soc.h>
 
 #include "rswitch.h"
 
@@ -1243,7 +1244,6 @@ static void rswitch_adjust_link(struct net_device *ndev)
 	struct rswitch_device *rdev = netdev_priv(ndev);
 	struct phy_device *phydev = ndev->phydev;
 
-	/* Current hardware has a restriction not to change speed at runtime */
 	if (phydev->link != rdev->etha->link) {
 		phy_print_status(phydev);
 		if (phydev->link)
@@ -1252,13 +1252,23 @@ static void rswitch_adjust_link(struct net_device *ndev)
 			phy_power_off(rdev->serdes);
 
 		rdev->etha->link = phydev->link;
+
+		if (!rdev->priv->etha_no_runtime_change &&
+		    phydev->speed != rdev->etha->speed) {
+			rdev->etha->speed = phydev->speed;
+
+			rswitch_etha_hw_init(rdev->etha, rdev->ndev->dev_addr);
+			phy_set_speed(rdev->serdes, rdev->etha->speed);
+		}
 	}
 }
 
 static void rswitch_phy_remove_link_mode(struct rswitch_device *rdev,
 					 struct phy_device *phydev)
 {
-	/* Current hardware has a restriction not to change speed at runtime */
+	if (!rdev->priv->etha_no_runtime_change)
+		return;
+
 	switch (rdev->etha->speed) {
 	case SPEED_2500:
 		phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_1000baseT_Full_BIT);
@@ -1347,7 +1357,8 @@ static int rswitch_ether_port_init_one(struct rswitch_device *rdev)
 		err = rswitch_etha_hw_init(rdev->etha, rdev->ndev->dev_addr);
 		if (err < 0)
 			return err;
-		rdev->etha->operated = true;
+		if (rdev->priv->etha_no_runtime_change)
+			rdev->etha->operated = true;
 	}
 
 	err = rswitch_mii_register(rdev);
@@ -1853,8 +1864,14 @@ static int rswitch_init(struct rswitch_private *priv)
 	return err;
 }
 
+static const struct soc_device_attribute rswitch_soc_no_speed_change[]  = {
+	{ .soc_id = "r8a779f0", .revision = "ES1.0" },
+	{ /* Sentinel */ }
+};
+
 static int renesas_eth_sw_probe(struct platform_device *pdev)
 {
+	const struct soc_device_attribute *attr;
 	struct rswitch_private *priv;
 	struct resource *res;
 	int ret;
@@ -1869,6 +1886,10 @@ static int renesas_eth_sw_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
+	attr = soc_device_match(rswitch_soc_no_speed_change);
+	if (attr)
+		priv->etha_no_runtime_change = true;
+
 	priv->ptp_priv = rcar_gen4_ptp_alloc(pdev);
 	if (!priv->ptp_priv)
 		return -ENOMEM;

drivers/net/ethernet/renesas/rswitch.h

@@ -1011,6 +1011,7 @@ struct rswitch_private {
 	struct rswitch_etha etha[RSWITCH_NUM_PORTS];
 	struct rswitch_mfwd mfwd;
 
+	bool etha_no_runtime_change;
 	bool gwca_halt;
 };