Merge tag 'v6.17.8' into linux-6.17.ylinux-6.17.y

This is the 6.17.8 stable release

1 files changed, 38 insertions, 1 deletions

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index 623292948fa7..0ea366c1217e 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -1902,6 +1902,43 @@ error:
 	return err;
 }
 
+/* m88e1510_resume
+ *
+ * The 88e1510 PHY has an erratum where the phy downshift counter is not cleared
+ * after phy being suspended(BMCR_PDOWN set) and then later resumed(BMCR_PDOWN
+ * cleared). This can cause the link to intermittently downshift to a lower speed.
+ *
+ * Disabling and re-enabling the downshift feature clears the counter, allowing
+ * the PHY to retry gigabit link negotiation up to the programmed retry count
+ * before downshifting. This behavior has been observed on copper links.
+ */
+static int m88e1510_resume(struct phy_device *phydev)
+{
+	int err;
+	u8 cnt = 0;
+
+	err = marvell_resume(phydev);
+	if (err < 0)
+		return err;
+
+	/* read downshift counter value */
+	err = m88e1011_get_downshift(phydev, &cnt);
+	if (err < 0)
+		return err;
+
+	if (cnt) {
+		/* downshift disabled */
+		err = m88e1011_set_downshift(phydev, 0);
+		if (err < 0)
+			return err;
+
+		/* downshift enabled, with previous counter value */
+		err = m88e1011_set_downshift(phydev, cnt);
+	}
+
+	return err;
+}
+
 static int marvell_aneg_done(struct phy_device *phydev)
 {
 	int retval = phy_read(phydev, MII_M1011_PHY_STATUS);
@@ -3923,7 +3960,7 @@ static struct phy_driver marvell_drivers[] = {
 		.handle_interrupt = marvell_handle_interrupt,
 		.get_wol = m88e1318_get_wol,
 		.set_wol = m88e1318_set_wol,
-		.resume = marvell_resume,
+		.resume = m88e1510_resume,
 		.suspend = marvell_suspend,
 		.read_page = marvell_read_page,
 		.write_page = marvell_write_page,