Merge branch 'support-loopback-mode-speed-selection'

Gerhard Engleder says:

====================
Support loopback mode speed selection

Previously to commit 6ff3cddc365b ("net: phylib: do not disable autoneg
for fixed speeds >= 1G") it was possible to select the speed of the
loopback mode by configuring a fixed speed before enabling the loopback
mode. Now autoneg is always enabled for >= 1G and a fixed speed of >= 1G
requires successful autoneg. Thus, the speed of the loopback mode depends
on the link partner for >= 1G. There is no technical reason to depend on
the link partner for loopback mode. With this behavior the loopback mode
is less useful for testing.

Allow PHYs to support optional speed selection for the loopback mode.
This support is implemented for the generic loopback support and for PHY
drivers, which obviously support speed selection for loopback mode.
Additionally, loopback support according to the data sheet is added to
the KSZ9031 PHY.

Extend phy_loopback() to signal link up and down if speed changes,
because a new link speed requires link up signalling.

Use this loopback speed selection in the tsnep driver to select the
loopback mode speed depending the previously active speed. User space
tests with 100 Mbps and 1 Gbps loopback are possible again.
====================

Link: https://patch.msgid.link/20250312203010.47429-1-gerhard@engleder-embedded.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/include/linux/phy.h b/include/linux/phy.h
index c24e1a565819..60d3b8860ea2 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1136,8 +1136,16 @@ struct phy_driver {
 	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 */
@@ -1800,7 +1808,7 @@ int phy_init_hw(struct phy_device *phydev);
 int phy_suspend(struct phy_device *phydev);
 int phy_resume(struct phy_device *phydev);
 int __phy_resume(struct phy_device *phydev);
-int phy_loopback(struct phy_device *phydev, bool enable);
+int phy_loopback(struct phy_device *phydev, bool enable, int speed);
 int phy_sfp_connect_phy(void *upstream, struct phy_device *phy);
 void phy_sfp_disconnect_phy(void *upstream, struct phy_device *phy);
 void phy_sfp_attach(void *upstream, struct sfp_bus *bus);
@@ -1915,7 +1923,7 @@ int genphy_read_status(struct phy_device *phydev);
 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);
 
@@ -1957,7 +1965,7 @@ int genphy_c45_pma_baset1_read_master_slave(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);