sfc: Test for PHYXS faults whenever we cannot test link state bits

Depending on the loopback mode, there may be no pertinent link state
bits.  In this case we test the PHYXS RX fault bit instead.  Make
sure to do this in all cases where there are no link state bits.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/sfc/mdio_10g.c

@@ -180,17 +180,12 @@ 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);
-		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)
+	else if (efx->loopback_mode == LOOPBACK_PCS)
 		mmd_mask &= ~(MDIO_MMDREG_DEVS_PCS |
 			      MDIO_MMDREG_DEVS_PMAPMD |
 			      MDIO_MMDREG_DEVS_AN);
@@ -198,6 +193,13 @@ bool mdio_clause45_links_ok(struct efx_nic *efx, unsigned int mmd_mask)
 		mmd_mask &= ~(MDIO_MMDREG_DEVS_PMAPMD |
 			      MDIO_MMDREG_DEVS_AN);
 
+	if (!mmd_mask) {
+		/* Use presence of XGMII faults in leui of link state */
+		reg = mdio_clause45_read(efx, phy_id, MDIO_MMD_PHYXS,
+					 MDIO_PHYXS_STATUS2);
+		return !(reg & (1 << MDIO_PHYXS_STATUS2_RX_FAULT_LBN));
+	}
+
 	while (mmd_mask) {
 		if (mmd_mask & 1) {
 			/* Double reads because link state is latched, and a