sfc: Fix unreliable link detection in some loopback modes

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 24 insertions, 13 deletions

diff --git a/drivers/net/sfc/mdio_10g.c b/drivers/net/sfc/mdio_10g.c
index 037601e0b9d7..f131ad2b6832 100644
--- a/drivers/net/sfc/mdio_10g.c
+++ b/drivers/net/sfc/mdio_10g.c
@@ -167,7 +167,7 @@ int mdio_clause45_check_mmds(struct efx_nic *efx,
 bool mdio_clause45_links_ok(struct efx_nic *efx, unsigned int mmd_mask)
 {
         int phy_id = efx->mii.phy_id;
-        int status;
+        u32 reg;
         bool ok = true;
         int mmd = 0;
 
@@ -179,12 +179,17 @@ bool mdio_clause45_links_ok(struct efx_nic *efx, unsigned int mmd_mask)
                 return false;
         else if (efx_phy_mode_disabled(efx->phy_mode))
                 return false;
-        else if (efx->loopback_mode == LOOPBACK_PHYXS)
+        else if (efx->loopback_mode == LOOPBACK_PHYXS) {
                 mmd_mask &= ~(MDIO_MMDREG_DEVS_PHYXS |
                               MDIO_MMDREG_DEVS_PCS |
                               MDIO_MMDREG_DEVS_PMAPMD |
                               MDIO_MMDREG_DEVS_AN);
-        else if (efx->loopback_mode == LOOPBACK_PCS)
+                if (!mmd_mask) {
+                        reg = mdio_clause45_read(efx, phy_id, MDIO_MMD_PHYXS,
+                                                 MDIO_PHYXS_STATUS2);
+                        return !(reg & (1 << MDIO_PHYXS_STATUS2_RX_FAULT_LBN));
+                }
+        } else if (efx->loopback_mode == LOOPBACK_PCS)
                 mmd_mask &= ~(MDIO_MMDREG_DEVS_PCS |
                               MDIO_MMDREG_DEVS_PMAPMD |
                               MDIO_MMDREG_DEVS_AN);
@@ -196,12 +201,11 @@ bool mdio_clause45_links_ok(struct efx_nic *efx, unsigned int mmd_mask)
                 if (mmd_mask & 1) {
                         /* Double reads because link state is latched, and a
                          * read moves the current state into the register */
-                        status = mdio_clause45_read(efx, phy_id,
-                                                    mmd, MDIO_MMDREG_STAT1);
-                        status = mdio_clause45_read(efx, phy_id,
-                                                    mmd, MDIO_MMDREG_STAT1);
-
-                        ok = ok && (status & (1 << MDIO_MMDREG_STAT1_LINK_LBN));
+                        reg = mdio_clause45_read(efx, phy_id,
+                                                 mmd, MDIO_MMDREG_STAT1);
+                        reg = mdio_clause45_read(efx, phy_id,
+                                                 mmd, MDIO_MMDREG_STAT1);
+                        ok = ok && (reg & (1 << MDIO_MMDREG_STAT1_LINK_LBN));
                 }
                 mmd_mask = (mmd_mask >> 1);
                 mmd++;
diff --git a/drivers/net/sfc/mdio_10g.h b/drivers/net/sfc/mdio_10g.h
index 409118228b1d..09bf801d0569 100644
--- a/drivers/net/sfc/mdio_10g.h
+++ b/drivers/net/sfc/mdio_10g.h
@@ -133,6 +133,10 @@
 #define MDIO_PMAPMD_10GBT_TXPWR_SHORT_LBN (0)
 #define MDIO_PMAPMD_10GBT_TXPWR_SHORT_WIDTH (1)
 
+/* PHY XGXS Status 2 */
+#define MDIO_PHYXS_STATUS2              (8)
+#define MDIO_PHYXS_STATUS2_RX_FAULT_LBN 10
+
 /* PHY XGXS lane state */
 #define MDIO_PHYXS_LANE_STATE           (0x18)
 #define MDIO_PHYXS_LANE_ALIGNED_LBN     (12)
diff --git a/drivers/net/sfc/tenxpress.c b/drivers/net/sfc/tenxpress.c
index b3ca2dc8040d..1567ab538e27 100644
--- a/drivers/net/sfc/tenxpress.c
+++ b/drivers/net/sfc/tenxpress.c
@@ -445,14 +445,13 @@ static bool sft9001_link_ok(struct efx_nic *efx, struct ethtool_cmd *ecmd)
         int phy_id = efx->mii.phy_id;
         u32 reg;
 
-        if (efx->loopback_mode == LOOPBACK_GPHY)
-                return true;
-        else if (efx_phy_mode_disabled(efx->phy_mode))
+        if (efx_phy_mode_disabled(efx->phy_mode))
                 return false;
+        else if (efx->loopback_mode == LOOPBACK_GPHY)
+                return true;
         else if (efx->loopback_mode)
                 return mdio_clause45_links_ok(efx,
                                               MDIO_MMDREG_DEVS_PMAPMD |
-                                              MDIO_MMDREG_DEVS_PCS |
                                               MDIO_MMDREG_DEVS_PHYXS);
 
         /* We must use the same definition of link state as LASI,
@@ -588,6 +587,10 @@ static void tenxpress_phy_poll(struct efx_nic *efx)
                                 change = true;
                 }
                 sfx7101_check_bad_lp(efx, link_ok);
+        } else if (efx->loopback_mode) {
+                bool link_ok = sft9001_link_ok(efx, NULL);
+                if (link_ok != efx->link_up)
+                        change = true;
         } else {
                 u32 status = mdio_clause45_read(efx, efx->mii.phy_id,
                                                 MDIO_MMD_PMAPMD,