[PATCH net v3 1/4] net: phy: as21xxx: handle stale link status during autoneg

[Christian Marangi <ansuelsmth@gmail.com>]

When autonegotiation is restarted, MDIO_STAT1_ANEGCOMPLETE may be
cleared before MDIO_STAT1_LSTATUS. In this case, the link status bit
may still indicate link up even though autonegotiation has not
completed.

Force the link down when autonegotiation is enabled but has not
completed, preventing as21xxx_read_status() from reporting a link up
with an unknown or stale speed.

Fixes: 830877d89edc ("net: phy: Add support for Aeonsemi AS21xxx PHYs")
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/phy/as21xxx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/phy/as21xxx.c b/drivers/net/phy/as21xxx.c
index d5738117eca6..0db82da8dbdf 100644
--- a/drivers/net/phy/as21xxx.c
+++ b/drivers/net/phy/as21xxx.c
@@ -658,6 +658,13 @@ static int as21xxx_read_link(struct phy_device *phydev, int *bmcr)
 		return status;
 
 	phydev->link = !!(status & MDIO_STAT1_LSTATUS);
+	phydev->autoneg_complete = !!(status & MDIO_AN_STAT1_COMPLETE);
+
+	/* Consider the case that autoneg was started and "aneg complete"
+	 * bit has been reset, but "link up" bit not yet.
+	 */
+	if (phydev->autoneg == AUTONEG_ENABLE && !phydev->autoneg_complete)
+		phydev->link = 0;
 
 	return 0;
 }
-- 
2.55.0