net: phy: marvell: support downshift as PHY tunable

So far downshift is implemented for one small use case only and can't
be controlled from userspace. So let's implement this feature properly
as a PHY tunable so that it can be controlled via ethtool.
More Marvell PHY's may support downshift, but I restricted it for now
to the ones where I have the datasheet.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index a7796134e3be0e287dbaa65d96e163c073b703e3..9716b39484c144ef3ed376008ee0269b52a41205 100644 (file)
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -54,11 +54,15 @@
 #define MII_M1011_PHY_SCR                      0x10
 #define MII_M1011_PHY_SCR_DOWNSHIFT_EN         BIT(11)
 #define MII_M1011_PHY_SCR_DOWNSHIFT_SHIFT      12
-#define MII_M1011_PHY_SRC_DOWNSHIFT_MASK       0x7800
+#define MII_M1011_PHY_SRC_DOWNSHIFT_MASK       GENMASK(14, 12)
+#define MII_M1011_PHY_SCR_DOWNSHIFT_MAX                8
 #define MII_M1011_PHY_SCR_MDI                  (0x0 << 5)
 #define MII_M1011_PHY_SCR_MDI_X                        (0x1 << 5)
 #define MII_M1011_PHY_SCR_AUTO_CROSS           (0x3 << 5)
 
+#define MII_M1011_PHY_SSR                      0x11
+#define MII_M1011_PHY_SSR_DOWNSHIFT            BIT(5)
+
 #define MII_M1111_PHY_LED_CONTROL      0x18
 #define MII_M1111_PHY_LED_DIRECT       0x4100
 #define MII_M1111_PHY_LED_COMBINE      0x411c
@@ -833,6 +837,79 @@ static int m88e1111_config_init(struct phy_device *phydev)
        return genphy_soft_reset(phydev);
 }
 
+static int m88e1111_get_downshift(struct phy_device *phydev, u8 *data)
+{
+       int val, cnt, enable;
+
+       val = phy_read(phydev, MII_M1011_PHY_SCR);
+       if (val < 0)
+               return val;
+
+       enable = FIELD_GET(MII_M1011_PHY_SCR_DOWNSHIFT_EN, val);
+       cnt = FIELD_GET(MII_M1011_PHY_SRC_DOWNSHIFT_MASK, val) + 1;
+
+       *data = enable ? cnt : DOWNSHIFT_DEV_DISABLE;
+
+       return 0;
+}
+
+static int m88e1111_set_downshift(struct phy_device *phydev, u8 cnt)
+{
+       int val;
+
+       if (cnt > MII_M1011_PHY_SCR_DOWNSHIFT_MAX)
+               return -E2BIG;
+
+       if (!cnt)
+               return phy_clear_bits(phydev, MII_M1011_PHY_SCR,
+                                     MII_M1011_PHY_SCR_DOWNSHIFT_EN);
+
+       val = MII_M1011_PHY_SCR_DOWNSHIFT_EN;
+       val |= FIELD_PREP(MII_M1011_PHY_SRC_DOWNSHIFT_MASK, cnt - 1);
+
+       return phy_modify(phydev, MII_M1011_PHY_SCR,
+                         MII_M1011_PHY_SCR_DOWNSHIFT_EN |
+                         MII_M1011_PHY_SRC_DOWNSHIFT_MASK,
+                         val);
+}
+
+static int m88e1111_get_tunable(struct phy_device *phydev,
+                               struct ethtool_tunable *tuna, void *data)
+{
+       switch (tuna->id) {
+       case ETHTOOL_PHY_DOWNSHIFT:
+               return m88e1111_get_downshift(phydev, data);
+       default:
+               return -EOPNOTSUPP;
+       }
+}
+
+static int m88e1111_set_tunable(struct phy_device *phydev,
+                               struct ethtool_tunable *tuna, const void *data)
+{
+       switch (tuna->id) {
+       case ETHTOOL_PHY_DOWNSHIFT:
+               return m88e1111_set_downshift(phydev, *(const u8 *)data);
+       default:
+               return -EOPNOTSUPP;
+       }
+}
+
+static void m88e1111_link_change_notify(struct phy_device *phydev)
+{
+       int status;
+
+       if (phydev->state != PHY_RUNNING)
+               return;
+
+       /* we may be on fiber page currently */
+       status = phy_read_paged(phydev, MII_MARVELL_COPPER_PAGE,
+                               MII_M1011_PHY_SSR);
+
+       if (status > 0 && status & MII_M1011_PHY_SSR_DOWNSHIFT)
+               phydev_warn(phydev, "Downshift occurred! Cabling may be defective.\n");
+}
+
 static int m88e1318_config_init(struct phy_device *phydev)
 {
        if (phy_interrupt_is_valid(phydev)) {
@@ -1117,6 +1194,8 @@ static int m88e1540_get_tunable(struct phy_device *phydev,
        switch (tuna->id) {
        case ETHTOOL_PHY_FAST_LINK_DOWN:
                return m88e1540_get_fld(phydev, data);
+       case ETHTOOL_PHY_DOWNSHIFT:
+               return m88e1111_get_downshift(phydev, data);
        default:
                return -EOPNOTSUPP;
        }
@@ -1128,6 +1207,8 @@ static int m88e1540_set_tunable(struct phy_device *phydev,
        switch (tuna->id) {
        case ETHTOOL_PHY_FAST_LINK_DOWN:
                return m88e1540_set_fld(phydev, data);
+       case ETHTOOL_PHY_DOWNSHIFT:
+               return m88e1111_set_downshift(phydev, *(const u8 *)data);
        default:
                return -EOPNOTSUPP;
        }
@@ -2220,6 +2301,9 @@ static struct phy_driver marvell_drivers[] = {
                .get_sset_count = marvell_get_sset_count,
                .get_strings = marvell_get_strings,
                .get_stats = marvell_get_stats,
+               .get_tunable = m88e1111_get_tunable,
+               .set_tunable = m88e1111_set_tunable,
+               .link_change_notify = m88e1111_link_change_notify,
        },
        {
                .phy_id = MARVELL_PHY_ID_88E1318S,
@@ -2359,6 +2443,7 @@ static struct phy_driver marvell_drivers[] = {
                .get_stats = marvell_get_stats,
                .get_tunable = m88e1540_get_tunable,
                .set_tunable = m88e1540_set_tunable,
+               .link_change_notify = m88e1111_link_change_notify,
        },
        {
                .phy_id = MARVELL_PHY_ID_88E1545,
@@ -2421,6 +2506,7 @@ static struct phy_driver marvell_drivers[] = {
                .get_stats = marvell_get_stats,
                .get_tunable = m88e1540_get_tunable,
                .set_tunable = m88e1540_set_tunable,
+               .link_change_notify = m88e1111_link_change_notify,
        },
 };