net: phy: Mask-out non-compatible modes when setting the max-speed

When setting a PHY's max speed using either the max-speed DT property
or ethtool, we should mask-out all non-compatible modes according to the
settings table, instead of just the 10/100BASET modes.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index cdea028d1328..855abf487279 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -4,6 +4,7 @@
  */
 #include <linux/export.h>
 #include <linux/phy.h>
+#include <linux/of.h>
 
 const char *phy_speed_to_str(int speed)
 {
@@ -338,6 +339,50 @@ size_t phy_speeds(unsigned int *speeds, size_t size,
 	return count;
 }
 
+static int __set_phy_supported(struct phy_device *phydev, u32 max_speed)
+{
+	const struct phy_setting *p;
+	int i;
+
+	for (i = 0, p = settings; i < ARRAY_SIZE(settings); i++, p++) {
+		if (p->speed > max_speed)
+			linkmode_clear_bit(p->bit, phydev->supported);
+		else
+			break;
+	}
+
+	return 0;
+}
+
+int phy_set_max_speed(struct phy_device *phydev, u32 max_speed)
+{
+	int err;
+
+	err = __set_phy_supported(phydev, max_speed);
+	if (err)
+		return err;
+
+	linkmode_copy(phydev->advertising, phydev->supported);
+
+	return 0;
+}
+EXPORT_SYMBOL(phy_set_max_speed);
+
+void of_set_phy_supported(struct phy_device *phydev)
+{
+	struct device_node *node = phydev->mdio.dev.of_node;
+	u32 max_speed;
+
+	if (!IS_ENABLED(CONFIG_OF_MDIO))
+		return;
+
+	if (!node)
+		return;
+
+	if (!of_property_read_u32(node, "max-speed", &max_speed))
+		__set_phy_supported(phydev, max_speed);
+}
+
 /**
  * phy_resolve_aneg_linkmode - resolve the advertisements into phy settings
  * @phydev: The phy_device struct