net: phy: Optionally force master mode for RTL PHY
This patch introduces CONFIG_RTL8211X_PHY_FORCE_MASTER. If this
define is set, RTL8211x PHYs (except for the RTL8211F) will have their
1000BASE-T master/slave autonegotiation disabled and forced to master
mode.
This is helpful for PHYs like the RTL8211C which produce unstable links
in slave mode. Such problems have been found on the A20-Olimex-SOM-EVB
and A20-OLinuXino-Lime2.
There is no proper way to identify affected PHYs in software as the
RTL8211C shares its UID with the RTL8211B. Thus, this fix requires
the introduction of an #ifdef.
CC: fradav@gmail.com
CC: merker@debian.org
CC: hdegoede@redhat.com
CC: ijc@hellion.org.uk
CC: joe.hershberger@ni.com
Signed-off-by: Michael Haas <haas@computerlinguist.org>
Tested-by: Karsten Merker <merker@debian.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 259a87f..359ec50 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -12,6 +12,10 @@
#define PHY_AUTONEGOTIATE_TIMEOUT 5000
+/* RTL8211x 1000BASE-T Control Register */
+#define MIIM_RTL8211x_CTRL1000T_MSCE (1 << 12);
+#define MIIM_RTL8211X_CTRL1000T_MASTER (1 << 11);
+
/* RTL8211x PHY Status Register */
#define MIIM_RTL8211x_PHY_STATUS 0x11
#define MIIM_RTL8211x_PHYSTAT_SPEED 0xc000
@@ -53,7 +57,14 @@
*/
phy_write(phydev, MDIO_DEVAD_NONE, MIIM_RTL8211x_PHY_INER,
MIIM_RTL8211x_PHY_INTR_DIS);
-
+#ifdef CONFIG_RTL8211X_PHY_FORCE_MASTER
+ unsigned int reg = phy_read(phydev, MDIO_DEVAD_NONE, MII_CTRL1000);
+ /* force manual master/slave configuration */
+ reg |= MIIM_RTL8211x_CTRL1000T_MSCE;
+ /* force master mode */
+ reg |= MIIM_RTL8211X_CTRL1000T_MASTER;
+ phy_write(phydev, MDIO_DEVAD_NONE, MII_CTRL1000, reg);
+#endif
/* read interrupt status just to clear it */
phy_read(phydev, MDIO_DEVAD_NONE, MIIM_RTL8211x_PHY_INER);