net: phy: Allow loopback speed selection for PHY drivers

PHY drivers support loopback mode, but it is not possible to select the
speed of the loopback mode. The speed is chosen by the set_loopback()
operation of the PHY driver. Same is valid for genphy_loopback().

There are PHYs that support loopback with different speeds. Extend
set_loopback() to make loopback speed selection possible.

Signed-off-by: Gerhard Engleder <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/phy/adin1100.c

···
 	return adin_set_powerdown_mode(phydev, false);
 }
 
-static int adin_set_loopback(struct phy_device *phydev, bool enable)
+static int adin_set_loopback(struct phy_device *phydev, bool enable, int speed)
 {
+	if (enable && speed)
+		return -EOPNOTSUPP;
+
 	if (enable)
 		return phy_set_bits_mmd(phydev, MDIO_MMD_PCS, MDIO_PCS_10T1L_CTRL,
 					BMCR_LOOPBACK);

drivers/net/phy/dp83867.c

···
 	}
 }
 
-static int dp83867_loopback(struct phy_device *phydev, bool enable)
+static int dp83867_loopback(struct phy_device *phydev, bool enable, int speed)
 {
+	if (enable && speed)
+		return -EOPNOTSUPP;
+
 	return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
 			  enable ? BMCR_LOOPBACK : 0);
 }

drivers/net/phy/marvell.c

···
 		data[i] = marvell_get_stat_simple(phydev, i);
 }
 
-static int m88e1510_loopback(struct phy_device *phydev, bool enable)
+static int m88e1510_loopback(struct phy_device *phydev, bool enable, int speed)
 {
 	int err;
 
 	if (enable) {
 		u16 bmcr_ctl, mscr2_ctl = 0;
+
+		if (speed == SPEED_10 || speed == SPEED_100 ||
+		    speed == SPEED_1000)
+			phydev->speed = speed;
+		else if (speed)
+			return -EINVAL;
 
 		bmcr_ctl = mii_bmcr_encode_fixed(phydev->speed, phydev->duplex);
 

drivers/net/phy/mxl-gpy.c

···
 	wol->wolopts = priv->wolopts;
 }
 
-static int gpy_loopback(struct phy_device *phydev, bool enable)
+static int gpy_loopback(struct phy_device *phydev, bool enable, int speed)
 {
 	struct gpy_priv *priv = phydev->priv;
 	u16 set = 0;
···
 
 	if (enable) {
 		u64 now = get_jiffies_64();
+
+		if (speed)
+			return -EOPNOTSUPP;
 
 		/* wait until 3 seconds from last disable */
 		if (time_before64(now, priv->lb_dis_to))
···
 	return 0;
 }
 
-static int gpy115_loopback(struct phy_device *phydev, bool enable)
+static int gpy115_loopback(struct phy_device *phydev, bool enable, int speed)
 {
 	struct gpy_priv *priv = phydev->priv;
 
 	if (enable)
-		return gpy_loopback(phydev, enable);
+		return gpy_loopback(phydev, enable, speed);
 
 	if (priv->fw_minor > 0x76)
-		return gpy_loopback(phydev, 0);
+		return gpy_loopback(phydev, 0, 0);
 
 	return genphy_soft_reset(phydev);
 }

drivers/net/phy/phy-c45.c

···
 }
 EXPORT_SYMBOL_GPL(gen10g_config_aneg);
 
-int genphy_c45_loopback(struct phy_device *phydev, bool enable)
+int genphy_c45_loopback(struct phy_device *phydev, bool enable, int speed)
 {
+	if (enable && speed)
+		return -EOPNOTSUPP;
+
 	return phy_modify_mmd(phydev, MDIO_MMD_PCS, MDIO_CTRL1,
 			      MDIO_PCS_CTRL1_LOOPBACK,
 			      enable ? MDIO_PCS_CTRL1_LOOPBACK : 0);

drivers/net/phy/phy_device.c

···
 	}
 
 	if (phydev->drv->set_loopback)
-		ret = phydev->drv->set_loopback(phydev, enable);
+		ret = phydev->drv->set_loopback(phydev, enable, 0);
 	else
-		ret = genphy_loopback(phydev, enable);
+		ret = genphy_loopback(phydev, enable, 0);
 
 	if (ret)
 		goto out;
···
 }
 EXPORT_SYMBOL(genphy_resume);
 
-int genphy_loopback(struct phy_device *phydev, bool enable)
+int genphy_loopback(struct phy_device *phydev, bool enable, int speed)
 {
 	if (enable) {
 		u16 ctl = BMCR_LOOPBACK;
 		int ret, val;
+
+		if (speed == SPEED_10 || speed == SPEED_100 ||
+		    speed == SPEED_1000)
+			phydev->speed = speed;
+		else if (speed)
+			return -EINVAL;
 
 		ctl |= mii_bmcr_encode_fixed(phydev->speed, phydev->duplex);
 

drivers/net/phy/xilinx_gmii2rgmii.c

···
 	return 0;
 }
 
-static int xgmiitorgmii_set_loopback(struct phy_device *phydev, bool enable)
+static int xgmiitorgmii_set_loopback(struct phy_device *phydev, bool enable,
+				     int speed)
 {
 	struct gmii2rgmii *priv = mdiodev_get_drvdata(&phydev->mdio);
 	int err;
 
 	if (priv->phy_drv->set_loopback)
-		err = priv->phy_drv->set_loopback(phydev, enable);
+		err = priv->phy_drv->set_loopback(phydev, enable, speed);
 	else
-		err = genphy_loopback(phydev, enable);
+		err = genphy_loopback(phydev, enable, speed);
 	if (err < 0)
 		return err;
 

include/linux/phy.h

···
 	int (*set_tunable)(struct phy_device *dev,
 			    struct ethtool_tunable *tuna,
 			    const void *data);
-	/** @set_loopback: Set the loopback mood of the PHY */
-	int (*set_loopback)(struct phy_device *dev, bool enable);
+	/**
+	 * @set_loopback: Set the loopback mode of the PHY
+	 * enable selects if the loopback mode is enabled or disabled. If the
+	 * loopback mode is enabled, then the speed of the loopback mode can be
+	 * requested with the speed argument. If the speed argument is zero,
+	 * then any speed can be selected. If the speed argument is > 0, then
+	 * this speed shall be selected for the loopback mode or EOPNOTSUPP
+	 * shall be returned if speed selection is not supported.
+	 */
+	int (*set_loopback)(struct phy_device *dev, bool enable, int speed);
 	/** @get_sqi: Get the signal quality indication */
 	int (*get_sqi)(struct phy_device *dev);
 	/** @get_sqi_max: Get the maximum signal quality indication */
···
 int genphy_read_master_slave(struct phy_device *phydev);
 int genphy_suspend(struct phy_device *phydev);
 int genphy_resume(struct phy_device *phydev);
-int genphy_loopback(struct phy_device *phydev, bool enable);
+int genphy_loopback(struct phy_device *phydev, bool enable, int speed);
 int genphy_soft_reset(struct phy_device *phydev);
 irqreturn_t genphy_handle_interrupt_no_ack(struct phy_device *phydev);
 
···
 int genphy_c45_read_status(struct phy_device *phydev);
 int genphy_c45_baset1_read_status(struct phy_device *phydev);
 int genphy_c45_config_aneg(struct phy_device *phydev);
-int genphy_c45_loopback(struct phy_device *phydev, bool enable);
+int genphy_c45_loopback(struct phy_device *phydev, bool enable, int speed);
 int genphy_c45_pma_resume(struct phy_device *phydev);
 int genphy_c45_pma_suspend(struct phy_device *phydev);
 int genphy_c45_fast_retrain(struct phy_device *phydev, bool enable);