net: phy: marvell-88q2xxx: add cable test support

Add cable test support for Marvell 88Q222x devices. Reported distance
granularity is 1m.

1m cable, open:
  Cable test started for device eth0.
  Cable test completed for device eth0.
  Pair A code Open Circuit
  Pair A, fault length: 1.00m

1m cable, shorted:
  Cable test started for device eth0.
  Cable test completed for device eth0.
  Pair A code Short within Pair
  Pair A, fault length: 1.00m

6m cable, open:
  Cable test started for device eth0.
  Cable test completed for device eth0.
  Pair A code Open Circuit
  Pair A, fault length: 6.00m

6m cable, shorted:
  Cable test started for device eth0.
  Cable test completed for device eth0.
  Pair A code Short within Pair
  Pair A, fault length: 6.00m

Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240218075753.18067-10-dima.fedrau@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/marvell-88q2xxx.c b/drivers/net/phy/marvell-88q2xxx.c
index 2ca1b47e8f8f5f4c0c5a277a508ef6d7f8ba2509..11963d8176b2ec5afda8cb7a0fe403c75a7f1cc3 100644 (file)
--- a/drivers/net/phy/marvell-88q2xxx.c
+++ b/drivers/net/phy/marvell-88q2xxx.c
@@ -72,6 +72,27 @@
 
 #define MDIO_MMD_PCS_MV_RX_STAT                        33328
 
+#define MDIO_MMD_PCS_MV_TDR_RESET                      65226
+#define MDIO_MMD_PCS_MV_TDR_RESET_TDR_RST              0x1000
+
+#define MDIO_MMD_PCS_MV_TDR_OFF_SHORT_CABLE            65241
+
+#define MDIO_MMD_PCS_MV_TDR_OFF_LONG_CABLE             65242
+
+#define MDIO_MMD_PCS_MV_TDR_STATUS                     65245
+#define MDIO_MMD_PCS_MV_TDR_STATUS_MASK                        0x0003
+#define MDIO_MMD_PCS_MV_TDR_STATUS_OFF                 0x0001
+#define MDIO_MMD_PCS_MV_TDR_STATUS_ON                  0x0002
+#define MDIO_MMD_PCS_MV_TDR_STATUS_DIST_MASK           0xff00
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_MASK       0x00f0
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_SHORT      0x0030
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_OPEN       0x00e0
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_OK         0x0070
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_IN_PROGR   0x0080
+#define MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_NOISE      0x0050
+
+#define MDIO_MMD_PCS_MV_TDR_OFF_CUTOFF                 65246
+
 struct mmd_val {
        int devad;
        u32 regnum;
@@ -715,6 +736,89 @@ static int mv88q222x_revb0_config_init(struct phy_device *phydev)
        return 0;
 }
 
+static int mv88q222x_cable_test_start(struct phy_device *phydev)
+{
+       int ret;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS,
+                           MDIO_MMD_PCS_MV_TDR_OFF_CUTOFF, 0x0058);
+       if (ret < 0)
+               return ret;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS,
+                           MDIO_MMD_PCS_MV_TDR_OFF_LONG_CABLE, 0x00eb);
+       if (ret < 0)
+               return ret;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS,
+                           MDIO_MMD_PCS_MV_TDR_OFF_SHORT_CABLE, 0x010e);
+       if (ret < 0)
+               return ret;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS, MDIO_MMD_PCS_MV_TDR_RESET,
+                           0x0d90);
+       if (ret < 0)
+               return ret;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS, MDIO_MMD_PCS_MV_TDR_STATUS,
+                           MDIO_MMD_PCS_MV_TDR_STATUS_ON);
+       if (ret < 0)
+               return ret;
+
+       /* According to the Marvell API the test is finished within 500 ms */
+       msleep(500);
+
+       return 0;
+}
+
+static int mv88q222x_cable_test_get_status(struct phy_device *phydev,
+                                          bool *finished)
+{
+       int ret, status;
+       u32 dist;
+
+       status = phy_read_mmd(phydev, MDIO_MMD_PCS, MDIO_MMD_PCS_MV_TDR_STATUS);
+       if (status < 0)
+               return status;
+
+       ret = phy_write_mmd(phydev, MDIO_MMD_PCS, MDIO_MMD_PCS_MV_TDR_RESET,
+                           MDIO_MMD_PCS_MV_TDR_RESET_TDR_RST | 0xd90);
+       if (ret < 0)
+               return ret;
+
+       /* Test could not be finished */
+       if (FIELD_GET(MDIO_MMD_PCS_MV_TDR_STATUS_MASK, status) !=
+           MDIO_MMD_PCS_MV_TDR_STATUS_OFF)
+               return -ETIMEDOUT;
+
+       *finished = true;
+       /* Fault length reported in meters, convert to centimeters */
+       dist = FIELD_GET(MDIO_MMD_PCS_MV_TDR_STATUS_DIST_MASK, status) * 100;
+       switch (status & MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_MASK) {
+       case MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_OPEN:
+               ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                       ETHTOOL_A_CABLE_RESULT_CODE_OPEN);
+               ethnl_cable_test_fault_length(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                             dist);
+               break;
+       case MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_SHORT:
+               ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                       ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT);
+               ethnl_cable_test_fault_length(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                             dist);
+               break;
+       case MDIO_MMD_PCS_MV_TDR_STATUS_VCT_STAT_OK:
+               ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                       ETHTOOL_A_CABLE_RESULT_CODE_OK);
+               break;
+       default:
+               ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A,
+                                       ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC);
+       }
+
+       return 0;
+}
+
 static struct phy_driver mv88q2xxx_driver[] = {
        {
                .phy_id                 = MARVELL_PHY_ID_88Q2110,
@@ -732,6 +836,7 @@ static struct phy_driver mv88q2xxx_driver[] = {
        {
                PHY_ID_MATCH_EXACT(PHY_ID_88Q2220_REVB0),
                .name                   = "mv88q2220",
+               .flags                  = PHY_POLL_CABLE_TEST,
                .probe                  = mv88q2xxx_probe,
                .get_features           = mv88q2xxx_get_features,
                .config_aneg            = mv88q222x_config_aneg,
@@ -742,6 +847,8 @@ static struct phy_driver mv88q2xxx_driver[] = {
                .config_intr            = mv88q2xxx_config_intr,
                .handle_interrupt       = mv88q2xxx_handle_interrupt,
                .set_loopback           = genphy_c45_loopback,
+               .cable_test_start       = mv88q222x_cable_test_start,
+               .cable_test_get_status  = mv88q222x_cable_test_get_status,
                .get_sqi                = mv88q2xxx_get_sqi,
                .get_sqi_max            = mv88q2xxx_get_sqi_max,
                .suspend                = mv88q2xxx_suspend,